DE102005063689B3 - Brake system with an electric motor-driven piston-cylinder system - Google Patents

Abstract

Brake system, having an actuating device, namely a brake pedal, and a control and regulating device, the control and regulating device using the movement and / or position of the actuating device to control an electromotive drive device, the drive device having a piston of a piston-cylinder system via a Adjusted non-hydraulic transmission device so that a pressure is set in the working chamber of the cylinder, the working chamber being connected to wheel brakes, in particular to two or four wheel brakes, via a pressure line or several pressure lines, with sensors and a travel simulator being provided to provide a to regulate variable pedal characteristics, whereby an assignment of the pressure to a pedal force is freely variable and takes place in a recuperable braking by means of a generator taking into account a correction value, so that the braking effect of the generator is taken into account ng of the brake system, is a brushless electric motor, in which three strings are controlled by means of a microcontroller, taking into account a determination of the position of the piston and a current measurement.

Description

According to claim 1, the present invention relates to a brake system, an actuating device, namely a brake pedal, and a control and regulating device.

State of the art:

Modern braking systems contain brake boosters, i. H. The pedal force is converted into a correspondingly increased braking torque on the wheel brakes and braking force regulation via open or closed regulation and control circuits. With a few exceptions in the passenger car sector, the hydraulic line is used as the transmission medium for generating the brake pressure from the pedal force.

A division into structural units between brake force boosting (BKV) or brake force control and brake force regulation in a hydraulic unit (HE) is widespread. This configuration is mainly used in systems such as anti-lock braking systems (ABS), anti-slip systems (ASR), electronic stability programs (ESP) or electro-hydraulic brakes (EHB).

The hydraulic unit (HE) usually consists of solenoid valves, multi-piston pumps for 2-circuit brake systems (front axle and rear axle), an electric motor for the pump drive, hydraulic accumulator and several pressure transducers. The pressure control is carried out in such a way that, in order to reduce the braking torque, pressure medium is drained from the wheel brakes into a reservoir via magnetic valves and is pumped back into the master brake cylinder by the pump, which causes a pedal movement. A corresponding system is out U.S. 4,057,301 A known.

Both rise and fall in pressure are controlled by solenoid valves, some of which use pressure transducers for solenoid valve control. With the exception of the EHB, the brake force amplification takes place with the vacuum BKV, which partly contains switching means and sensors for the so-called brake assistant function and also for the detection of the so-called control point. The internal combustion engine is used as the energy source for the vacuum in Otto engines, but as a direct injection engine, especially at great heights, it only delivers a weak vacuum. A mechanical or electrically driven vacuum pump is used in diesel engines. The latest ESP systems are able to achieve additional brake force boosting by switching the solenoid valves and pump or, if the BKV fails, brake force boosting with a larger time constant. The description of these systems and functions is described in detail in the brake manual Vieweg Verlag, edition 2003.

In the mid-1980s, Teves used the so-called Mark II and Bosch used the ABS3, which, as integrated units, contained all the components for brake booster and control with a hydraulic brake system, see Bosch Automotive Handbook 1986, 20th edition. For reasons of cost, these systems have not caught on, except for use in special protection vehicles. The same applies to fully electric brake systems, so-called EMB, with electric motors on the wheel brakes, which were developed intensively in connection with the 42 V on-board network. In addition to the additional costs, a new redundant on-board network is necessary for the energy supply in order to ensure the braking capability of a brake circuit in the event of a fault.

The type of EMB systems also includes the wedge brake with an electric motor drive. A redundant on-board network is also necessary for this despite the lower energy requirement. The structural implementation of the wedge brake, which for reasons of hysteresis requires additional roles that require integration into the brake caliper, has not been solved at the moment. The wedge brake with its electromotive drives with sensors has to withstand the harsh environmental conditions (dust, water, high temperatures). Furthermore, some development efforts within the industry focused on improved pedal characteristics. The US 6 315 371 B1 teaches that an interrupt device and a corresponding controller between the master brake cylinder and the actuating device can be used to achieve an advantageous pedal characteristic in the sense of the shortest possible pedal travel.

Another important control / regulation for improving the pedal characteristics goes from the US 2003/0 160 503 A1 emerged. It describes that the rate of pressure reduction can advantageously be reduced in such a way that the compression modulus of the liquid does not change and thus negative, microscopic bubbles in the pressure chamber of the brake system can be avoided.

The systems for BKV and HE are very well developed, especially the control and regulation functions for ABS to ESP. For example, the pressure-controlled control of the solenoid valves enables very fine dosing of the Brake pressure possible, with which a variable brake force adjustment EBV is possible. A braking system is out of the DE 33 42 552 A1 known. In this brake system, the main brake cylinder is used to generate a pedal-dependent pressure that serves as a reference variable for an electronic control and regulating device which regulates the output pressure of an electrohydraulic servo device directly connected to the brake circuit to a value determined by the reference variable. If the control device or the servo device itself fails, the pressure in the brake circuit is generated by the master cylinder. Instead of the reference variable generated in normal operation by means of the master brake cylinder, it is possible to have a reference variable generated within the scope of an anti-lock braking system or as part of a slip control of the drive control of the motor vehicle act on the electronic control and regulation device and thus on the electrohydraulic servo device. The servo device has an electrically operated hydraulic piston-cylinder unit, the working space of which is connected to the brake circuit and the piston of which is axially adjustable by means of an electric motor. The rotary movement of the electric motor is converted into a longitudinal movement of the piston via a spindle connected to the piston. Another system is from the DE 33 42 552 A1 known that when the front axle locks, the brake pressure of the rear axle increases accordingly so that there is a reduced pressure on the front axle, which causes the front wheel to lock. A similar system is also from the DE 39 14 401 A1 known.

Out WO 2004/005 095 A1 a brake system is previously known in which an electric motor drives the pistons of a piston-cylinder system via a spindle drive. The pistons are not permanently coupled to the spindle, so that the maximum piston speed when the spindle retracts and thus the maximum pressure reduction speed is determined by the strength of the compression springs in the piston-cylinder system. The brake pressure to be set in the wheel brakes is determined by means of a pressure sensor, the pressure being the control variable of the brake pressure control.

The DE 37 23 916 A1 and DE 34 40 972 A1 show systems with a hydraulic brake booster which, in addition to pure brake booster, also implements the ABS function. In the pressure line, which connects the piston-cylinder system and the respective wheel brake, only one valve is arranged, which is opened to change the pressure in the wheel brake and closed to maintain the wheel brake pressure. With this brake pressure control, too, the pressure is the controlled variable.

Out DE 195 00 544 A1 an electronically controllable brake actuation system for anti-lock motor vehicle brake systems is previously known, in which a master brake cylinder can be actuated by means of a brake pedal. The actuation path of the brake pedal is determined by means of a sensor, which represents an input variable for a control unit which controls several brake pressure transducers to which the vehicle brakes are connected directly or via solenoid valves by means of hydraulic lines. The connection of the hydraulic lines to the master brake cylinder can be shut off by a valve device. In order to increase the functional reliability, especially in the event of an electrical defect or failure of the vehicle electronics, the piston of the master cylinder can be adjusted in the fallback level directly by means of the brake pedal to build up pressure in the wheel brakes, the valve device being open for this purpose. The brake pressure transducers each have an electric drive which adjusts a piston in a cylinder so that a pressure is established in the brake circuit which is determined by means of a pressure sensor and fed to the control unit as an input variable. The pressure is also the controlled variable in this brake pressure control. A similar braking system is off DE 103 04 145 A1 and the DE 195 43 583 C1 previously known. Out DE 44 45 975 A1 a brake system for motor vehicles is known in which the brake pressure in a wheel brake is regulated by means of an electric motor-driven piston of a piston-cylinder system, a pressure sensor for measuring the controlled variable also being provided in this brake system. A 2/2-way valve is used to hold the brake pressure in the wheel brake, by means of which the hydraulic line between the piston-cylinder system and the wheel brake can be shut off.

DE 103 18 401 A1 discloses a motor-driven vehicle brake device in which the position of the brake pedal is determined by means of a travel sensor and transmitted to a control unit. Depending on the driving condition and the brake pedal position, the control unit controls an electromotive drive of a piston-cylinder system, which is used to build up pressure in the brake circuits. A mechanical connection between the piston of the piston-cylinder system and the brake pedal is not provided, so that in the fall-back level no pressure can be built up in the wheel brakes by means of the brake pedal. The pressure in the wheel brakes is regulated by means of inlet and outlet valves assigned to the respective wheel brakes. A similar braking system is off DE 32 41 662 A1 and DE 197 50 977 A1 known.

DE 199 36 433 A1 and DE 100 57 557 A1 disclose brake systems in which on the piston of the master cylinder, which can be adjusted by the brake pedal, by means of electromagnetic drives, a supporting Force can be applied. In these brake systems, too, the pressure in the master cylinder is the controlled variable of the brake pressure control process.

Furthermore, from the EP 08 40 441 B1 a field-oriented control is known which allows a rotary field machine that works in both drive and generator mode to be controlled in such a way that unfavorable overcurrents are avoided. It describes the possibilities of a controller-based solution for regulating a specified generator (braking) torque. In this way, it is possible in the case of a rotary field machine, knowing the stator currents, the motor speed, the rotor speed and the flux-dependent inductances, to set a desired braking torque by means of the voltage components.

Object of the invention

The present invention has the object of providing a novel brake system.

This object is advantageously achieved by a brake system having the features of claim 1. Further advantageous embodiments of the brake system according to claim 1 result from the features of the subclaims.

The brake system according to the invention is advantageously characterized in that it realizes the brake force boosting and the servo device in the smallest space per brake circuit by means of only one piston-cylinder unit. The piston-cylinder unit can also be used to build up and reduce brake pressure, to implement ABS and anti-slip control, as well as in the event of failure of the power supply or malfunction of the drive device. This advantageously results in a small, integrated and cost-effective structural unit for the brake booster (BKV) and control, which results in savings in installation space, assembly costs and additional hydraulic and vacuum connecting lines. In addition, due to the short overall length, the spring dome, for example, does not have an advantageous effect on the master cylinder and the pedals in a front crash.

Thanks to the advantageous provision of a sensor system and a travel simulator, variable pedal characteristics such as brake-by-wire function, i.e. brake pressure increase independently of pedal actuation, can be regulated in a freely variable manner, also taking into account the braking effect of the generator in the case of regenerative brakes.

From the specialist literature, e.g. Schröder D., Electrical Drives Regulation of Drive Systems, 2nd Edition, Springer-Verlag Berlin Heidelberg, 2001, it is known that, with knowledge of the fixed, geometric variables (number of pole pairs), the motor-typical inductances (from the data sheet of the motor ) as well as the measurable currents I _E (or _{P, M} ); I _q ; I _d a generator braking torque can be estimated. A similar braking system that takes a regenerative braking torque into account DE 199 39 950 A1 known.

Likewise, with the corresponding design, there is no disadvantageous dropping of the brake pedal if the drive fails, since the pedal acts directly on the piston of the system. This also advantageously results in lower pedal forces if the power supply fails, since the pistons have a smaller effective area than conventional master brake cylinders. This is possible by separating the piston path when the reinforcement is intact and the reinforcement has failed. One speaks here of a gear ratio jump, which reduces the pedal force for the same braking effect by up to 40%. The reduction in the overall effort, including the electrical connections, also results in an advantageous reduction in the failure rate.

The electromotive drive can furthermore improve the ABS / ESP control by means of finely metered pressure control with variable pressure increase and, in particular, pressure decrease speeds. A pressure reduction below 1 bar in the area of the vacuum is also necessary for function with the smallest coefficients of friction, e.g. B. wet ice, possible. A rapid increase in pressure at the start of braking, e.g. 0 - 100 bar, can be achieved in less than 50 ms, which results in a considerable reduction in the braking distance.

Due to the advantageous provision of a 2/2-way valve for the brake booster and the control function, the brake system according to the invention requires considerably less energy.

It is also possible to provide a separate piston-cylinder system with an associated drive for each brake circuit or each wheel brake. It is also possible to use a piston-cylinder system in which two pistons are arranged axially displaceably in a cylinder, the cylinders are hydraulically coupled and only one piston is mechanically driven by the drive device by an electric motor.

Various configurations of the brake system according to the invention are explained in more detail below with reference to drawings.

• 1 : Eine erste Ausführungsform einer Bremsanlage mit einem Bremskreis für zwei Radbremsen;
• 2: eine zweite Ausführungsform der Bremsanlage mit zwei Kolben-Zylinder-Systemen für zwei Bremskreise für jeweils zwei Radbremsen;
• 3: einen Wegsimulator für das erfindungsgemäße Bremssystem;
• 4: ein Kolben-Zylinder-System mit einem Zylinder und zwei Kolben;
• 5 und 5a: Verbindung zwischen Betätigungseinrichtung und Kolben-Zylinder-Systemen;
• 6: eine Seitenansicht der integrierten Baueinheit mit Gehäuse;
• 7: Kennlinien des Bremssystems;
• 8 und 8a: Kolbenantrieb über eine Kurbelschwinge
• 9: Kolbenantrieb über eine Spindel
• 10: Kolbenbetätigung mit überlagerter Pedalkraft

Show it:

• 1 : A first embodiment of a brake system with a brake circuit for two wheel brakes;
• 2 : a second embodiment of the brake system with two piston-cylinder systems for two brake circuits for two wheel brakes each;
• 3rd : a travel simulator for the braking system according to the invention;
• 4th : a piston-cylinder system with one cylinder and two pistons;
• 5 and 5a : Connection between actuation device and piston-cylinder systems;
• 6th : a side view of the integrated unit with housing;
• 7th : Characteristics of the braking system;
• 8th and 8a : Piston drive via a crank arm
• 9 : Piston drive via a spindle
• 10 : Piston actuation with superimposed pedal force

The 1 shows a section of the integrated unit that is responsible for generating pressure or boosting the brake force. This is where the piston 1 with the usual seals 2 and 3rd in the cylinder housing 4th parallel to the piston via a specially designed rack 5a emotional. The seal 2 is designed in such a way that it can also operate when there is negative pressure in the piston chamber 4 ' seals. This rack 5a transfers the force to the front, spherical end of the piston 1 . This has a collar bolt at this point 1a over which the rack 5a with return spring 9 brings the piston to the starting position. Here the rack is on the cylinder housing 4a at. This external spring has the advantage that the cylinder is short and has little dead space, which is advantageous for ventilation. Because of the transverse forces, the rack has a bearing in the rollers 10 and 11 with slide 12th . The 1 clearly shows that the parallel arrangement of the rack to the piston results in a short overall length. The structural unit must be very short in order to be outside the crash zone. The rack is through an in 5a The H-profile shown is very rigid. The arrangement of the rollers is chosen so that the rack is in the end position 5b (shown in dashed lines) with the greatest bending force due to the offset pressure force has a relatively small bending length. The rack is over tooth profile 5a ' and gear 6th about the gear wheel 7th from the pinion of the motor 8th driven. This motor with a small time constant is preferably a brushless motor as a bell-shaped rotor with ironless winding or preferably a motor in accordance with the PCT patent applications WO 2006/000259 A1 and WO 2006/000260 A1 . This is from the power amplifiers 21 preferably via three lines from a microcontroller (MC) 22nd controlled. A shunt measures for this 23 the current and a sensor signal 24 and indicates the position of the rotor and, via corresponding counters, the position of the piston. In addition to the motor control, the current and position measurement is used for indirect pressure measurement, since the motor torque is proportional to the pressure force. For this purpose, a map must be created in the vehicle during commissioning and also during operation, in which the position of the piston is assigned to the various flow strengths. During operation, a position of the piston is then approached in accordance with the booster characteristic curve described later, which position corresponds to a specific pressure in accordance with the characteristic diagram. If the position and engine torque do not quite match, e.g. B. by the influence of temperature, the map is adapted during operation. This means that the map is continuously adapted. The output map is formed from the pressure-volume characteristic curve of the wheel brake, the engine parameter, the transmission efficiency and the vehicle deceleration. With the latter, a vehicle deceleration proportional to the pedal force can be achieved so that the driver does not have to adjust to different braking effects.

The piston 1 generated in the line 13th a corresponding pressure, which is generated via the 2/2 solenoid valve (MV) 14th to the wheel brake 15th or via solenoid valve MV 16 to the wheel brake 17th got. This arrangement described above has several advantages. Instead of the two inexpensive small solenoid valves, another piston-motor unit could be used, as shown in 4th is shown. However, this means considerably more costs, weight and installation space.

It is sufficient to use a piston-motor unit for each brake circuit.

The second advantage is the very low energy requirement and the design of the motor for pulse operation only. This is achieved by closing the solenoid valves when the setpoint value for the pressure or engine torque is reached and the motor is then only operated with a low current until a new setpoint value is specified by the brake pedal. This means that the energy requirement or the average output is extremely small. For example, in the case of a conventional design, when the brakes are fully applied from 100 km / h, the engine would 3rd draw a high current. According to the invention, the motor requires only approx. 0.05 s of current for the piston travel, which is 1.7%. If the values are related to the power, then in the conventional case the on-board network would be loaded with> 1000 W for at least 3 s and with the proposed impulse operation only approx. 50 W average power. An even greater energy saving results from emergency braking from 250 km / h with braking times of up to 10 s on a dry road. A storage capacitor can be used here to relieve the pulse load on the vehicle electrical system 27 can be used in the power supply, which can also be used for the other electric motors according to the line with the arrow.

In the pressure line 13th Pressure transducers can be used before or after the solenoid valve, which are not shown because they correspond to the state of the art.

The piston 1 is filled with liquid from the storage container through the sniffer hole 18th provided. There is a solenoid valve in this line 19th switched on. If the piston moves quickly to reduce the pressure, the seal could 3rd Sniff liquid from the reservoir, especially at low pressures, which is known to be disadvantageous. The low-pressure solenoid valve is used for this 19th switched on and the connection to the storage container interrupted. With this circuit, there can also be negative pressure in the wheel circles 15th / 17th can be achieved what the wheel control with very small coefficients of friction z. B. benefits on wet ice, since no braking torque is generated in the wheel brake. On the other hand, re-sniffing can be used deliberately in the event of vapor bubbles forming, when the piston is already at the stop without the corresponding pressure being reached. The pistons are controlled accordingly with the solenoid valves so that the oscillating piston builds up pressure. If this function is not used, the solenoid valve 19th a sniff-proof seal 3rd can be used.

The solenoid valves 14th , 16 , 19th are via power amplifiers 28 from the microcontroller 22nd controlled.

If the power supply or the electric motor fails, the piston is actuated by a lever 26th the actuator moves. Between this and the piston there is a built-in play that prevents the lever from hitting the piston before the motor moves the piston when the pedal is pressed quickly.

The control function with regard to wheel speed and wheel pressure with ABS / ASR or yaw rate and wheel pressure with ESP has been presented in various publications, so that it will not be described again. The main functions of the new system are to be shown in a table: print print Functions Electric motor Wheel brake 15 Solenoid valve 14 1 Wheel brake 17 Solenoid valve 15 1 BKV A construction 0 construction 0 partially energized P = constant 1 P = constant 1 partially energized Dismantling 0 Dismantling 0 Brake control A construction 0 construction 0 partially energized P = constant 1 P = constant 0 A construction 0 P = constant 1 partially energized Dismantling 0 P = constant 1 partially energized Dismantling 0 Dismantling 0

The amount of partial current flow depends on the rate of pressure increase or decrease desired by the BKV or the brake control. The decisive factor here is an extremely small time constant of the electric motor, ie a rapid increase in torque and torque reduction over small moving masses of the entire drive, since the piston speed determines the speed of pressure change. In addition, rapid and precise position control of the pistons is necessary for brake control. In the case of the rapid torque reduction, the pressure force originating from the brake caliper also has a supporting effect, but this is low at low pressures. But it is precisely here that the rate of pressure drop should also be large in order to avoid large deviations from the wheel speed on z. B. Avoid ice.

This concept has a decisive advantage over conventional pressure control via solenoid valves, since the piston speed determines the rate of pressure change. For example, if there is a small differential pressure at the outlet valve that determines the pressure reduction, the flow rate and thus the rate of pressure reduction are low. As already mentioned, the piston unit can be used separately for each wheel with and without a solenoid valve. In order to take advantage of the low energy consumption, the electric motor would have to be expanded with a fast electromagnetic brake, which is, however, more complex. The embodiment shown with a piston unit and two solenoid valves is preferable in terms of installation space and costs. In terms of control engineering, however, the restriction applies here that if there is a pressure reduction in one wheel, the other wheel cannot build up any pressure. However, since the pressure reduction time is approx. <10% of the pressure build-up time in the control cycle, this restriction has no significant disadvantage. The control algorithms must be adapted accordingly, e.g. after a phase of constant pressure from opening the solenoid valve, the electric motor must be excited with a current to which the appropriate pressure in the wheel brake is assigned according to the BKV characteristic curve or is e.g. 20% higher than the previous locking pressure in Control cycle. Alternatively, for example, an adaptive pressure level that is 20% higher than the highest locking pressure of the axle or the vehicle can also be set during control. The locking pressure is the pressure at which the wheel slips unstably.

The concept also offers new possibilities for pressure reduction in terms of control technology. In terms of control technology, the pressure reduction and braking torque reduction are essentially proportional to the rotational acceleration of the wheel, the hysteresis of the seal and inversely proportional to the moment of inertia of the wheel. The amount of the required pressure reduction can be calculated from these values and the piston can already provide the corresponding volume when the MV is closed, taking into account the characteristic diagram described. When the MV then opens, there is a very rapid drop in pressure practically in the vacuum. This is based on the fact that the MV has a smaller throttling effect in contrast to today's solutions due to the corresponding opening cross-sections. In this case, the pressure reduction can take place faster than with conventional solutions via a specially provided chamber volume in accordance with the pressure volume characteristic. Alternatively, a pressure reduction in a chamber volume that is slightly larger than the required pressure reduction is possible, e.g. by adjusting the piston accordingly. For precise regulation of the pressure reduction, a very short switching time is required to close the solenoid valve, which can preferably be achieved by pre-excitation and / or overexcitation. In addition, for special control cases, it is advantageous to bring the armature of the 2/2 solenoid valve into an intermediate position using known PWM processes in order to generate a throttling effect.

The very rapid reduction in pressure can possibly generate pressure oscillations that affect the wheel. In order to avoid this harmful effect, the piston travel can be controlled accordingly as a further alternative, e.g. 80% of the required pressure reduction (rapid pressure reduction). The remaining 20% of the pressure reduction required can then be done slowly by a subsequently controlled slow piston movement or, in the alternative, with pressure reduction control via solenoid valves by clocking the solenoid valve and stepped reduction. This avoids damaging wheel vibrations. The slow pressure reduction can be continued until the wheel accelerates again with the ABS control.

This means that very small control deviations in the wheel speed are possible. The method described above can also be applied to the pressure build-up. The speed of the pressure increase can be optimized according to control criteria. In this way, the goal can be achieved that the wheel is braked in the immediate vicinity of the maximum frictional force and thus optimal braking effect is achieved with optimal driving stability.

Special cases of regulation were mentioned above in which a throttling effect is advantageous. This is the case, for example, if both wheels need to be reduced in pressure at the same time. The throttling effect is advantageous here until the actuating piston has provided such a large chamber volume that the subsequent rapid pressure reduction into the vacuum can take place from different pressure levels. The procedure is similar, ie if the solenoid valves have a built-in throttle in the valve cross-section and pressure is to be built up on both wheel circles at the same time. However, the individual, alternating pressure build-up is to be preferred because of the metered pressure build-up with evaluation of the characteristic field and more regulated Adjustment speed of the piston. The same alternating method can be used as an alternative to the above with the throttling effect for the pressure reduction. As a further possibility, the piston can already be moved back with a control signal with a lower response threshold than the control signal for the pressure reduction. According to the state of the art, this is the signal at which the controller detects a tendency to block and the MV switches to pressure holding. This signal is issued 5-10 ms before the signal to reduce pressure. The proposed fast drive is able to provide a chamber volume for a pressure reduction of 10 bar within approx. 5 ms.

On the basis of the piston position for pressure reduction, the controller can decide whether there is sufficient chamber volume for the simultaneous pressure reduction for both wheel brakes.

These explanations show that the concept with the fast and variably regulated electromotive piston drive and the solenoid valve with the evaluation of the pressure and characteristic field represents a high potential for the controller, which enables additional braking distances and driving stability.

The 2 shows the entire integrated unit for BKV and control functions. The unit consists of two piston units with associated electric motors and gears in accordance with. 1 for two brake circuits and four wheel brakes. The piston units are in the housing 4th housed. This housing is on the front wall 29 attached.

The brake pedal 30th transmits the pedal force and movement via the bearing pin 31 on a fork piece 32 , which is attached to the actuating device via a ball joint 33 works. This has a cylindrical extension 34 with a pole 35 .

cylinder 34 and rod 35 are in a socket 37 stored. This takes the travel simulator springs 36 and 36a on, with one spring acting weakly and the other spring acting strongly progressively in the increase in force. The path simulator can also be constructed from even more springs or rubber elements. This specifies the pedal force characteristics. The pedal travel is determined by a sensor 38 detected, which in the example shown is built according to the eddy current principle, in which the rod 35 immersed with a target.

The pedal movement is on the elements 32 and 33 transferred to the piston 34 moves with the rod 35 in the socket 37 . There is a lever on the actuator 26th rotatably mounted, which hits the piston in the event of a power failure. The pedal travel sensor supplies the travel signal to the electronic control unit, which is generated according to the BKV characteristic curve as shown in 7th is described, causes a movement of the piston via the electric motor. The parameters of this characteristic are shown in 7th described in more detail. Between the lever 26th and the two pistons 1 there is provided a clearance s _o, as shown in 1 shown. The actuator has over the bolt 39 , which is shown offset, a rotation lock and a return spring 40 , which supports the pedal return spring, not shown. According to the state of the art, many travel simulator solutions are known, some of which are also actuated hydraulically via pistons and shut off via solenoid valves if the energy supply fails. This solution is complex and subject to hysteresis. Solutions are also known in which the path simulator path is included as a loss path in the event of failure of the energy supply when the piston is actuated to generate the brake pressure.

The aim of the invention is a simple solution in which the path simulator is switched off if the power supply fails. To do this, it is on the socket 37 with intact energy supply via the armature lever 41 with a large transmission ratio and the holding magnets 42 exerted a counterforce that is not applicable if the electrical power supply fails. Two-stage levers can also be used to reduce the magnet. This is detailed in 3rd described. In this case, the lever comes into contact with the two pistons via the brake pedal after passing through the play and can thus transmit the pedal force to the pistons. The pistons are dimensioned so that they generate a pressure at full pedal stroke, which still gives a good braking effect, e.g. B. 80%. However, the piston stroke is considerably greater than the pedal stroke and can generate much higher braking pressures if the energy supply and the electric drive are intact. However, the driver cannot apply the necessary pedal force. In this design, one speaks of a gear ratio jump, which is possible by decoupling the actuation unit with travel simulator from the piston. With a conventional design, in which the brake system and master brake cylinder with pistons are connected in series, the required pedal force increases by a factor if the power supply fails 5 for the same wheel brake pressure. In the new design, for. B. the factor can be reduced to 3. This case is e.g. B. relevant when towing a vehicle with a failed battery.

The lever 26th is rotatably mounted so that it can take into account tolerances in the movement of the pistons, e.g. B. due to different venting. This compensation can also be limited so that the lever hits a stop 33a the actuating device comes to rest.

However, there are still other error cases to be considered.

Failure of an electric motor.

In this case, the amplification and control are fully effective in the neighboring intact piston drive. Via the lever 26th Brake pressure is generated in the failed circuit after it hits the stop 33a is present. The amplifier characteristic curve of the second circuit can also be increased here, which reduces the pedal force required. However, this can also be done without a stop.

Brake circuit failure.

Here the piston moves to the stop in the housing 4th . The intact second circle is fully effective. Unlike conventional systems today, there is no falling pedal, which is known to be very irritating to the driver. The irritation can also lead to a complete loss of braking effect if he does not depress the pedal.

The 3rd describes the function of the travel simulator locking. In borderline cases, the driver can apply high pedal forces, which is the locking mechanism via the anchor lever 41 must raise. To avoid the magnet 42 with excitation coil 43 must fully apply these forces, the upper convex end engages 41a of the lever asymmetrically on the socket 37 at. Now press the pedal until it hits the bar 35 on the ground 37b deflected, this leverage causes a slight twisting of the bushing 37 what creates friction in the guide, with the addition of the nose 37a on the housing 4th can support. Thus, the magnetic force can be kept relatively small. The magnet is also used as a holding magnet 42 designed so that a small holding power is necessary due to the small air gap. If the power supply fails, the armature lever 41 from the socket 37 in the dot-dash position 41 ' deflected. When the actuator 33 goes back to the starting position, brings the return spring 44 the anchor lever back to its original position.

The sensor 38 was attached to the end of the bore of the socket in the housing 4th offset, which has advantages for contacting the electronic control unit, as shown in 6th is shown. The same goes for the brake light switch 46 . In this embodiment, the target is 45 drawn for the eddy current sensor.

The locking of the travel simulator via the socket 37 can be changed to match the in 7th to avoid the pedal reaction described in ABS. The lever 41 with its storage and magnet 42 with recording 42a via an electric motor 60 be moved by a spindle 60a via a transmission 60b drives. The lever is mounted on the extension of the spindle and the magnet housing is attached.

The 4th shows a basic representation of a solution with only one electric motor 7a . This description builds on 1 and 2 on. The drive pinion of the motor moves the rack 5c which similar 1 can also be offset in parallel. This is with a piston 1a connected what pressure in the brake circuit 13a builds up and at the same time the piston via the pressure 1a that moves in the brake circuit 13th Pressure builds up. This piston arrangement corresponds to a conventional master brake cylinder for whose piston and seal designs there are many variants. As in the previous figures, there are 2/2-way solenoid valves in the brake circuits 14th , 14a , 15th , 15a arranged. The ABS pressure modulation takes place in the manner described above. The BKV function takes place via a path simulation arranged in parallel 36 and displacement sensor 38 . Here, too, is between pistons 1a and brake pedal a play or idle stroke s _{0 is} provided. The brake fluid comes from the reservoir 18th , 18a into the piston chambers. This arrangement is inexpensive. The dynamics of the BKV function in the pressure build-up is less than in the variant with two motors, since the electric motor has to generate twice the torque. In addition, the redundancy function of the 2nd motor as shown in 7th including a pedal failing in the event of a brake circuit failure.

The 5 shows the view from the front wall of the integrated structural unit, its flange 4b by means of screws 47 is screwed to the front wall. The actuation unit can be seen here 33 , Lever 26th and a bolt not shown offset 39 as an anti-twist device. To compare the size, the outline of a 10 "vacuum BKV is drawn in. This shows an important advantage in the overall height with the cover 48 of the storage container. According to the distance A, the front wall could be lowered, which the Designers want. To the left of the flange is pointing out 5a , dashed the drive of the rack 5 drawn. This detail is enlarged as 5a shown on the right half of the picture. The pinion of the gear 6th engages in the H-shaped design of the rack on both sides 5 . The described transverse forces are exerted by the role 10 or. 11 corresponding 1 with storage 10a supported. For reasons of cost, the rack can be made of plastic. Since the surface pressure is not sufficient, hard metal strips are used here 49 inserted, which adapt to the roles with a slightly convex design of the support. In the pinion 6th is the gear 7th pressed in, which is in engagement with the motor pinion. The pinion is preferably in the motor housing 8a stored.

The 6th shows the side view of the integrated unit with housing 4th , Fork piece 32 for brake pedal 30th , Actuation unit 33 , Flange 45 , Fastening screws 47 , Cover 48 . This view shows the short overall length with the electronic control unit on the front 50 is appropriate. This is according to the prior art with the coils or part of the magnetic circuit of the solenoid valves 14th u. 16 connected in order to save additional contacting and electrical connection lines. This feature can be extended by all electrical components such as electric motor 8th , Solenoid 43 , Displacement sensor 38 , Brake light switch 46 , Brake fluid level sensor 53 can be contacted directly with the control unit without electrical connection lines. In this case, the control unit would have to be directed from above 50a to be built in. However, it's also headed 50b possible, which results in a changed arrangement of the solenoid.

The solenoid valves are preferably on a carrier plate 51 attached, as these are pressed into aluminum with high elongation at break for reasons of cost. The locking screws are placed in this carrier plate 52 screwed in for the brake lines. In the middle part of the control unit, the contact is drawn, which is in the area 54 a redundant power supply, in the area 55 the bus line, at 56 which includes sensors for ABS and ESP.

The 7th shows the main characteristics of the braking system. Pedal force F _P , braking force pressure p and pedal travel on the actuation unit are shown. Usually, a ratio of 4 to 5 is selected from here to the pedal foot. The pedal travel has its maximum at S _P and the piston, as already mentioned, at a higher value s _K. With 57 the so-called pressure-travel characteristic is shown, which here z. B. corresponds to a brake circuit. The non-linear course results from various elasticities such as those of the brake caliper, seals, lines, residual air inclusions and compressibility of the fluid. This line shows the mean value of a scatter band, which is also temperature-dependent, especially for the brake caliper. Therefore, a map must be created for the flow-proportional pressure control.

The characteristics 59 show the failure of the electric drive, in which the pistons are actuated _{after play S 0.} To achieve 100 bar, for example, the described considerably higher pedal forces F _PA of approx. 600 N are necessary, which corresponds to a pedal force that is more than 40% lower than with today's solutions.

From the pedal position and the brake pressure it can be seen that the pressure modulation of 10 bar does not affect the pedal at locking pressures> 50 bar, since the pedal hits the lock _{at S S.} In the case of lower blocking pressures, when the pressure is lowered and built up, there is a reaction on the pedal when the pedal is fully depressed, and is thus comparable with today's ESP and ABS systems. However, it is possible to reduce or avoid the retroactive effect by using an in 4th described electric motor 60 , which adjusts the locking of the travel simulator via a drive. About the piston drive 6th the pedal is moved back to lower the pressure. At this point in time, the motor adjusts the drive with little force. This also enables a pedal movement to warn the driver, e.g. B. in a traffic jam or the like. Even without this additional motor, a reaction is possible if the pedal movement is greater than the play S _o and the pistons are briefly retracted as a warning.

The thicker lines are the enhancer lines 58 and 58a , which shows the assignment of pedal force F _P to brake pressure. At approx. 50% of the maximum pedal travel, the travel simulator is fully _{controlled at S S.} This has the advantage that full braking is possible with a short pedal travel. The pedal travel is determined by the sensor 38 detected. The assignment of the pressure to the pedal force is freely variable and can, for. B. also take into account the vehicle deceleration in the dotted line by including this as a correction value in the gain, so that when the brake fades, a higher pressure is applied with the same pedal force. This correction is also necessary in systems with recuperation of the braking energy via the generator, since the braking effect of the generator must be taken into account. The same applies to panic braking with a high Pedal speed. Here, a much higher pressure can be fed in disproportionately to the pedal force, which with a time delay follows the static characteristic curve shown (solid line).

At F _P1 , a foot force of 200 N is usually set for the brake pressure of 100 bar. This pressure corresponds to the blocking limit on a dry road. In this area, the path simulator characteristic is almost linear, so that good metering is guaranteed. As a rule, a maximum pressure of 160 bar is sufficient, according to which the endurance strength of the elements is dimensioned. For infrequent loads, however, a reserve R can be kept, which can take effect, for example, if the blocking limit has not yet been reached at 160 bar.

In the event of a power failure, the electric drive can be viewed as more fail-safe than the vacuum BKV, since at least two electric motor drives are used for the proposed invention, i.e. one has a redundant effect and is known to be the total failure rate λ _g = λ ₁ λ ₂ . A failure of the power supply while driving can almost be ruled out, since the generator and battery practically never fail at the same time. A break in the electrical power supply is caused by the in 7th described redundant power supply prevented. The vacuum BKV is not redundant with amplifier elements, supply lines and possibly a pump.

The 8th shows another solution of the piston drive. Instead of the rack, a crank arm can be used 60 are used, which have a tension strut 61 over the bearing pin 62 is connected to the piston. The return spring 9 acts on the crank arm, whose starting position is determined by the stop 65 given is. The crank arm is via a multi-stage gear 63 from the engine 11 driven.

The 8a shows a two-armed rocker arm 60 and 60a with two tension struts 61 and 61a . This means that only small transverse forces act on the piston. The gear 63 is encapsulated here in an extended motor housing 64 and is from the drive pinion 11a of the motor 11 driven. The advantage of this solution lies in the encapsulation of the gearbox, which enables oil or grease to be filled, allows helical gearing and is therefore more resilient and quieter.

The 9 shows a further alternative with a spindle drive which is arranged inside the rotor of the electric motor. This arrangement is from the DE 195 11 287 B4 known relating to electromechanically operated disc brakes. In the solution presented is the mother 67 as a separate component in the bore of the rotor 66 and leans on the flange 66a of the rotor. The pressure forces of the piston act on this 1 . The spindle drive also acts as a reduction gear, whereby the spindle 65 transfers the force to the piston. All drives shown so far have a reduction gear that is permanently coupled to the piston, which moves the brake pedal in the event of a power failure and has to be accelerated with the motor when the pedal is pressed quickly. These inertial forces prevent rapid pedal actuation and irritate the driver. To avoid this, the nut can move axially in the bore of the rotor so that the ball screw drive is switched off when the pedal is engaged. For normal operation with an electric motor, the nut is fixed by a 70 mm lever, which is effective when the piston is reset quickly, especially when there is a vacuum in the piston chamber. This lever is over the shaft 71 stored in the rotor and, when the motor is not rotating, is controlled by the spring 72 moved to a position in which the nut is free. Since the drive motor accelerates extremely quickly, the centrifugal force acts on the lever and the nut is enclosed by the lever for the movement of the piston.

This movement can also be brought about by an electromagnet shown in dashed lines, in which the lever represents a rotating armature. The torque generated by the nut on the spindle is provided by two bearing pins 69 and 69a caught. These pins are also carriers of the return spring 9 . The rotor is preferably in a ball bearing 74 stored, which absorbs the axial forces of the piston and in a plain bearing 75 , which can also be a roller bearing. This solution requires a greater overall length, which is in comparison with 9 It becomes clear that the length of immersion of the spindle in the nut is equal to the piston stroke. In order to keep this extension small, the motor housing is 74 directly on the piston housing 4th flanged. This also has the advantage of different material choices for the motor and piston housing.

The mother 67 can also be used directly with the rotor 66 be connected, e.g. B. by injection. A plastic nut with a low coefficient of friction can be used for the required forces.

If a motor or the power supply fails, the pedal (not shown) acts accordingly on the fork piece 2 and over the lever 26th after the idle travel so on the spindle 65 or piston 1 . Since a blocking of the drive has to be switched off with this solution, the stop can 33 have a smaller distance to the lever. This has the advantage that the pedal force acts fully on the piston when z. B. an electric motor fails. As soon as the lever is supported on the opposite end as it rotates, only half the pedal force acts on the piston. In the structural design, the spindle and piston are decoupled, which was not carried out separately.

The return of the piston to the starting position is important. If the motor fails in an intermediate position, the piston return spring can also be supported by a spiral spring 66a which at the end of the rotor 66 and the motor housing 74 is arranged and coupled to this. This is intended to compensate for the cogging torque and the frictional torque of the motor. This is particularly advantageous for small restoring forces of the pistons, which act on the pedal in the event of a power failure in connection with the in 9 described clutch lever.

The 10 shows a further simplified embodiment with an electromotive piston drive, in which the piston in turn 1 performs the brake booster and pressure modulation for ABS. The piston chambers 1' are according to the 1 to 9 over lines 13th and 13a connected to the wheel brakes (not shown) and to the solenoid valves, also not shown. The structure corresponds 8th with spindle drive 65 and with rotor 66 , firmly attached mother 67 , Separation of engine and piston, housing 74 or. 4th , Piston return springs 9 and bearing pin 69 , Coil spring 66a to reset the engine. The pedal force becomes similar 2 from a fork piece 26th on an actuator 34 with rod 35 transfer. This is in the motor housing 74 stored and carries a target in the extension 45 e.g. for an eddy current sensor 38 which measures the pedal travel. The actuation device is via a spring 79 deferred. On the actuation device 35 is again a lever 26th stored, which at the end in the connection to the piston is preferably leaf springs 76 carries, which with a strong leaf spring with a displacement transducer 77 or with a softer spring with a force transmitter 77a are connected. In both cases, the force transmitted by the lever or pedal is to be measured here. The leaf spring 76 has the task of using the pedal to avoid a hard reaction before the motor starts running. The function takes place in such a way that the motors exert a reinforcing force on the piston in a specific function of this pedal force, this force in turn being determined from the current and piston travel or a pressure transducer. Here, the pedal travel can be via the travel sensor 38 be processed in this amplifier function or characteristic curve. This sensor can also be used in conjunction with the return spring at the beginning of braking at low pressures 76 take over the amplifier function. Here the pen takes over 79 the function of the travel simulator spring.

The motor housing has a flange for fastening the unit via the screw bolts 78 in the front wall. This simplified concept does not have the expense of the travel simulator and locking. The disadvantage is the limited pedal travel characteristic of the booster characteristic, the pedal falling through if the brake circuit fails, and higher pedal forces if the boost fails, since the pedal travel and piston travel are identical. This version is mainly suitable for small vehicles.

In the embodiment according to. 10 are representative of all solutions safety valves 80 shown, which take effect if, for example, a piston drive jams when the pedal returns to its starting position. When the pedal is moved, a conical extension of the actuator 35 the two safety valves 80 operated, which the connection from the brake circuit 13th or. 13a close to return. This ensures that when the pedal is in the starting position, no brake pressure is built up in the brake circuit. These valves can also be operated electromagnetically.

Safety-relevant systems usually have a separate switch-off option for errors in the output stages, e.g. full current flow through failure. In this case, a switch-off option is built in, e.g. by means of a conventional relay. The diagnostic part of the electrical circuit detects this error and switches off the relay which normally supplies the output stages with power. The concepts proposed here must also include a switch-off option, which is implemented by a relay or a central MOSFET.

In view of the impulse control of the electric motors, a fuse can also be used, since the pulse-off ratio is very large.

• Ausführungsbeispiel 1:
  • Bremsanlage, eine Betätigungseinrichtung, insbesondere ein Bremspedal, und eine Steuer- und Regeleinrichtung aufweisend, wobei die Steuer- und Regeleinrichtung anhand der Bewegung und/oder Position der Betätigungseinrichtung eine elektromotorische Antriebsvorrichtung steuert, wobei die Antriebsvorrichtung einen Kolben eines Kolben-Zylinder-Systems über eine nicht-hydraulische Getriebevorrichtung verstellt, so dass sich im Arbeitsraum des Zylinders ein Druck einstellt, wobei der Arbeitsraum über eine Druckleitung mit einer Radbremse in Verbindung ist, dadurch gekennzeichnet , dass bei Ausfall der Antriebsvorrichtung die Betätigungseinrichtung den Kolben (1) oder die Antriebsvorrichtung verstellt.
• Ausführungsbeispiel 2:
  • Bremsanlage nach Ausführungsbeispiel 1, dadurch gekennzeichnet , dass eine Sensoreinrichtung die Stellung der Betätigungseinrichtung ermittelt.
• Ausführungsbeispiel 3:
  • Bremsanlage nach Ausführungsbeispiel 1 oder 2, dadurch gekennzeichnet, dass eine Einrichtung, insbesondere eine Haptikeinrichtung, zur Vorgabe oder Einstellung einer Kraft/Weg-Charakteristik der Betätigungseinrichtung mit dieser in Wirkverbindung ist.
• Ausführungsbeispiel 4:
  • Bremsanlage nach einem der Ausführungsbeispiele 1 bis 3, dadurch gekennzeichnet , dass in der Druckleitung (13) zur Radbremse (15, 17) ein von der Steuer- und Regeleinrichtung (22) gesteuertes Ventil (14, 16) angeordnet ist.
• Ausführungsbeispiel 5:
  • Bremsanlage nach Ausführungsbeispiel 4, dadurch gekennzeichnet, dass das Ventil (14, 16) nach Erreichen des erforderlichen Bremsdrucks im Bremszylinder (15, 17) schließt und zur Einstellung eines neuen Bremsdrucks geöffnet ist.
• Ausführungsbeispiel 6:
  • Bremsanlage nach einem der Ausführungsbeispiele 1 bis 5, dadurch gekennzeichnet, dass der Kolben (1) die erforderliche Druckänderung für die Bremskraftverstärkung (BKV) und das Antiblockiersystem (ABS) erzeugt.
• Ausführungsbeispiel 7:
  • Bremsanlage nach einem der Ausführungsbeispiele 1 bis 6, dadurch gekennzeichnet, dass eine Feder (9) den Kolben (1) oder die Antriebsvorrichtung kraftbeaufschlagt, wobei die Federkraft in die Richtung wirkt, das der Arbeitsraum vergrößert wird.
• Ausführungsbeispiel 8:
  • Bremsanlage nach einem der Ausführungsbeispiele 1 bis 7, dadurch gekennzeichnet, dass die Antriebsvorrichtung mindestens einen Elektromotor (8) mit insbesondere kleiner Zeitkonstante und/oder ein großes Beschleunigungsvermögen aufweist.
• Ausführungsbeispiel 9:
  • Bremsanlage nach Ausführungsbeispiel 8, dadurch gekennzeichnet, dass der Elektromotor (8) bei geschlossenem Ventil (14, 16) mit einem Erregerstrom bestromt wird, der dazu ausreicht, den Kolben (1) gegen die Federkraft in Position zu halten.
• Ausführungsbeispiel 10:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass jeder Bremskreis ein Kolben-Zylinder-System aufweist.
• Ausführungsbeispiel 11:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass der Arbeitsraum (4') über zwei oder mehr Druckleitungen (13) mit mehreren Bremszylindern (15, 17) in Verbindung ist, wobei jeweils ein Ventil (14, 16) in jeder Druckleitung (13) angeordnet ist.
• Ausführungsbeispiel 12:
  • Bremsanlage nach einem der Ausführungsbeispiel 4 bis 11, dadurch gekennzeichnet, dass das Ventil (14, 16) ein 2/2-Wegeventil ist.
• Ausführungsbeispiel 13:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass das Kolben-Zylinder-System einen ersten und einen zweiten Kolben (1a, 1b) aufweist, welche in einem Zylinder axial verschieblich angeordnet sind, wobei der erste Kolben (1a) mechanisch mit der elektromotorischen Antriebsvorrichtung (7a, 6, 5c) und der zweite Kolben (1b) hydraulisch mit dem ersten Kolben (1a) gekoppelt ist, wobei die beiden Kolben (1a, 1b) zwischen sich einen Arbeitsraum (4a') bilden, der über mindestens eine Druckleitung (13a) mit mindestens einem Bremszylinder verbunden ist, und der zweite Kolben (1b) mit dem Zylinder einen zweiten Arbeitsraum (4b') bildet, der über mindestens eine weitere Druckleitung (13) mit mindestens einem weiteren Bremszylinder verbunden ist.
• Ausführungsbeispiel 14:
  • Bremsanlage nach Ausführungsbeispiel 13, dadurch gekennzeichnet, dass in den Druckleitungen (13, 13a) von der Steuer- und Regeleinrichtung gesteuerte Ventile 14, 15, 14a, 15a), insbesondere 2/2-Wegeventile, angeordnet sind.
• Ausführungsbeispiel 15:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, d a durc h gekennzeichnet, dass bei der Erzeugung der Bremskraftverstärkung die Betätigungsvorrichtung nicht oder nicht in direkter mechanischer Verbindung mit dem Kolben oder der Antriebseinrichtung ist, und lediglich bei Ausfall der Antriebsvorrichtung oder bei Aktivierung des ABS der Kolben in mechanischer Verbindung mit der Betätigungsvorrichtung ist.
• Ausführungsbeispiel 16:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass zwei Kolben-Zylinder-Systeme mit jeweils dazugehöriger Antriebsvorrichtung nebeneinander, insbesondere parallel zueinander angeordnet sind, wobei die Betätigungseinrichtung (30) direkt oder über zwischengeschaltete Mittel bei Ausfall mindestens einer Antriebsvorrichtung mindestens einen der beiden Kolben verstellt.
• Ausführungsbeispiel 17:
  • Bremsanlage nach Ausführungsbeispiel 16, dadurch gekennzeichnet, dass die Betätigungseinrichtung einen Hebel oder den Drehpunkt einer Wippe (26) parallel zum Verstellweg der Kolben (1) der Kolben-Zylinder-Systeme verstellt, und jedes freie Ende eines Arms der Wippe (26) jeweils einem Kolben (1) zugeordnet ist.
• Ausführungsbeispiel 18:
  • Bremsanlage nach Ausführungsbeispiel 17, dadurch gekennzeichnet, dass ein Begrenzungselement (33) den Verschwenkbereich der Wippe (26) begrenzt.
• Ausführungsbeispiel 19:
  • Bremsanlage nach einem der Ausführungsbeispiele 16 bis 18, dadurch gekennzeichnet, dass die Wippe (26) an einem Kolben (34) gelagert ist, welcher in einem Zylinder parallel zu den von den Antreiben angetriebenen Kolben (1) verschieblich gelagert ist, wobei der Kolben (34) mittels mindestens einer, insbesondere nichtlinearen Feder (36, 36a) in Richtung Bremspedal druckbeaufschlagt ist, und die Feder zusammen mit dem Kolben einen sog. Wegsimulator bildet, und ein Sensor die Position des Kolben bestimmt.
• Ausführungsbeispiel 20:
  • Bremsanlage nach Ausführungsbeispiel 19, dadurch gekennzeichnet, dass der Kolbenhub des mit der Wippe (26) verbundenen Kolbens (34) durch einen Anschlag begrenzt ist, wobei der Anschlag über eine insbesondere elektromagnetische Stelleinrichtung abschaltbar ist.
• Ausführungsbeispiel 21:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennze ich net, dass ein Kanal den Arbeitsraum (4') der Kolben-Zylindereinheit mit einem Reservoir (18) verbindet, wobei der Kolben (1) den Kanal (20) beim Einfahren in den Zylinder verschließt und der Kanal (20) in der Ausgangsstellung, d.h. lediglich bei fast oder vollständig zurückgefahrenem Kolben (1), geöffnet ist.
• Ausführungsbeispiel 22:
  • Bremsanlage nach Ausführungsbeispiel 21, dadurch gekennzeichnet, dass ein Absperrventil, insbesondere ein 2/2-Wegeventil (19) im Kanal (20) angeordnet ist.
• Ausführungsbeispiel 23
  • Bremsanlage nach Ausführungsbeispiel 22, dadurch gekennzeichnet, dass die Dichtung des Kolbens bei schneller Rückstellung des Kolbens aus dem Vorratsbehälter keine Flüssigkeit infolge Vakuum im Arbeitsraum nachschnüffelt.
• Ausführungsbeispiel 24:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass der Antrieb eine Zahnstange (5a) antreibt, welche parallel zum Verstellweg des Kolbens (1), insbesondere neben dem Kolben, verschieblich und insbesondere reibungsarm gelagert ist, wobei die Zahnstange über ein Koppelglied (5) mit dem Kolben (1) insbesondere fest in Verbindung ist.
• Ausführungsbeispiel 25:
  • Bremsanlage nach Ausführungsbeispiel 16, dadurch gekennzeichnet, dass eine Feder (9) das Koppelglied oder die Zahnstange druckbeaufschlagt.
• Ausführungsbeispiel 26:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuerung in Abhängigkeit der Bewegung und/oder Kraftbeaufschlagung des Bremspedals und/oder des Fahrzustandes und/oder Bremswirkung einer elektrischen Maschine eine entsprechende Bremskraftverstärkung einregelt.
• Ausführungsbeispiel 27:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekenn z eich n et, dass die Steuerung den Bremsdruck im Arbeitsraum des Zylinders aus das dem Antriebsstrom des Antriebs ermittelt.
• Ausführungsbeispiel 28:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele 1 bis 16, dadurch gekenn z eich n et, dass ein Drucksensor zur Ermittlung des Bremsdrucks im Arbeitsraum des Zylinders vorgesehen ist.
• Ausführungsbeispiel 29:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuer- und Regeleinrichtung einen Speicher hat, in dem ein Kennfeld mit verschiedenen Parametern zur Steuerung des Antriebs gespeichert ist.
• Ausführungsbeispiel 30:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuerung mittels mindestens eines Sensors, insbesondere eines Inkrementalgebers des Elektromotors die Kolbenposition ermittelt.
• Ausführungsbeispiel 31:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass der Antrieb den Kolben aus dem Zylinder herausfährt, damit dieser mechanisch mit dem Bremspedal in Verbindung kommt und eine Kraft auf das Bremspedal ausübt.
• Ausführungsbeispiel 32:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuerung zur Erzeugung eines schnellen Druckabbaus in der Radbremse vor dem Öffnen des jeweiligen Ventils ein Unterdruck mittels des zugehörigen Kolbens durch Vergrößern des Arbeitsraumes erzeugt.
• Ausführungsbeispiel 33:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuer- und Regeleinrichtung zum Aufbau eines erhöhten Blockierdrucks vor dem Öffnen des jeweiligen Ventils den Elektromotor der Antriebsvorrichtung mit ca. 120% des im Regelzyklus vorausgegangenen Blockierdrucks bestromt.
• Ausführungsbeispiel 34:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass schnelle Energiespeicher für das Speichern von elektrischer Energie, insbesondere Kondensatoren mit großer Kapazität, zur Erzeugung von Impulsströmen vorgesehen sind.
• Ausführungsbeispiel 35:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass ein zusätzlicher Antrieb die Betätigungseinrichtung oder den Anschlag des Wegsimulators verstellt, derart, das im Normalbetrieb die Betätigungseinrichtung nicht in mechanischer Verbindung zum Kolben ist.
• Ausführungsbeispiel 36:
  • Bremsanlage nach Ausführungsbeispiel 35, dadurch gekennzeichnet, dass der zusätzliche Antrieb auf einen Wegsimulator wirkt, wobei bei einem niedrigem Blockierdruck der zusätzliche Antrieb den Wegsimulator während der Druckabsenkung in die Ausgangsstellung zurückbewegt, derart, dass die Betätigungseinrichtung mechanisch nicht mit dem Kolben in Verbindung ist.
• Ausführungsbeispiel 37:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Steuer- und Regeleinrichtung das Ventil zum schnellen Schließen vorerregt, so dass das Ventil durch eine kleine Erregungsverstärkung unmittelbar schließt.
• Ausführungsbeispiel 38:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Antriebsvorrichtung mindestens eine Kolbenschwinge (60, 61) aufweist, mittels derer der Kolben verstellbar ist.
• Ausführungsbeispiel 39:
  • Bremsanlage nach Ausführungsbeispiel 38, dadurch gekennzeichnet, dass die Kolbenschwinge eine doppelarmige Kurbelschwinge (60, 60a) ist.
• Ausführungsbeispiel 40:
  • Bremsanlage nach Ausführungsbeispiel 38 oder 39, dadurch gekennzeichnet, dass das Getriebe ein abgekapseltes Getriebe ist und insbesondere im Motorgehäuse eingelagert ist.
• Ausführungsbeispiel 41:
  • Bremsanlage nach einem der Ausführungsbeispiele 1 bis 37, dadurch gekennzeichnet, dass der Kolben mittels eines innerhalb von dem Rotor eines Elektromotors angeordneten Spindelantrieb angetrieben ist.
• Ausführungsbeispiel 42:
  • Bremsanlage nach Ausführungsbeispiel 41, dadurch gekennzeichnet, dass der Rotor über eine axial im Rotor verschieblich gelagerte Mutter den Kolben antreibt, wobei die Mutter über einen insbesondere mittels Elektromagnet oder Fliehkraft betätigten Hebel bei Drehung des Rotors in axialer Position gehalten ist, und bei Ausfall des elektrischen Antriebs die Spindel mitsamt der Mutter axial im Rotor verschiebbar ist.
• Ausführungsbeispiel 43:
  • Bremsanlage nach Ausführungsbeispiel 41 oder 42, dadurch gekennzeichnet, dass eine Verdrehsicherung der Spindel über zwei Lagerstifte außerhalb des Kolbens, welche zugleich die Kolbenrückstellfedern aufnehmen, erfolgt.
• Ausführungsbeispiel 44:
  • Bremsanlage nach einem der Ausführungsbeispiele 41 bis 43, dadurch gekennzeichnet, dass eine Drehfeder den Motor zurückstellt.
• Ausführungsbeispiel 45:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass die Bremsanlage eine zur Pedalkraft proportionale Verstärkung einregelt, wobei die Bremsanlage die Pedalkraft am Kolben ermittelt.
• Ausführungsbeispiel 46:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass zwischen der Betätigungseinrichtung und dem jeweiligen Kolben ein Dämpfungselement, insbesondere in Form einer Blattfeder angeordnet ist, wobei die Blattfeder insbesondere an der Wippe (26) angeordnet ist, und dass an der Wippe oder dem Dämpfungselement ein Kraft und/oder Wegsensor zur Pedalkraftmessung angeordnet ist.
• Ausführungsbeispiel 47:
  • Bremsanlage nach einem der vorhergehenden Ausführungsbeispiele, dadurch gekennzeichnet, dass ein Kanal den Arbeitsraum (1') mit dem Reservoir verbindet, in dem ein Sicherheitsventil (80) angeordnet ist, welches im Falle eines klemmenden Kolbens öffnet und den Arbeitsraum (1') zum Druckabbau im Arbeitsraum mit dem Reservoir (18) verbindet.
• Ausführungsbeispiel 48:
  • Bremsanlage nach Ausführungsbeispiel 47, dadurch gekennzeichnet, dass das Sicherheitsventil ein mechanisch-hydraulisches oder ein elektromagnetisches Ventil ist.

Embodiments of the invention follow.

• Embodiment 1:
  • Brake system, having an actuating device, in particular a brake pedal, and a control and regulating device, the control and regulating device controlling an electromotive drive device based on the movement and / or position of the actuating device, the drive device having a piston of a piston-cylinder system via a Adjusted non-hydraulic transmission device so that a pressure is set in the working space of the cylinder, the working space being connected to a wheel brake via a pressure line, characterized in that, if the drive device fails, the actuating device actuates the piston ( 1 ) or the drive device is adjusted.
• Embodiment 2:
  • Brake system according to the embodiment 1 , characterized in that a sensor device determines the position of the actuating device.
• Embodiment 3:
  • Brake system according to exemplary embodiment 1 or 2, characterized in that a device, in particular a haptic device, for specifying or setting a force / path characteristic of the actuating device is in operative connection therewith.
• Embodiment 4:
  • Brake system according to one of the exemplary embodiments 1 to 3, characterized in that in the pressure line ( 13th ) to the wheel brake ( 15th , 17th ) one from the control and regulation device ( 22nd ) controlled valve ( 14th , 16 ) is arranged.
• Embodiment 5:
  • Brake system according to embodiment 4, characterized in that the valve ( 14th , 16 ) after reaching the required brake pressure in the brake cylinder ( 15th , 17th ) closes and is open to set a new brake pressure.
• Embodiment 6:
  • Brake system according to one of the exemplary embodiments 1 to 5, characterized in that the piston ( 1 ) generates the pressure change required for the brake booster (BKV) and the anti-lock braking system (ABS).
• Embodiment 7:
  • Brake system according to one of the exemplary embodiments 1 to 6, characterized in that a spring ( 9 ) the piston ( 1 ) or force is applied to the drive device, the spring force acting in the direction that the working space is enlarged.
• Embodiment 8:
  • Brake system according to one of the exemplary embodiments 1 to 7, characterized in that the drive device has at least one electric motor ( 8th ) has a particularly small time constant and / or a high acceleration capacity.
• Embodiment 9:
  • Brake system according to embodiment 8, characterized in that the electric motor ( 8th ) with the valve closed ( 14th , 16 ) is energized with an excitation current that is sufficient to drive the piston ( 1 ) to hold against the spring force in position.
• Embodiment 10:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that each brake circuit has a piston-cylinder system.
• Embodiment 11:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the working space ( 4 ' ) via two or more pressure lines ( 13th ) with several brake cylinders ( 15th , 17th ) is connected, with one valve ( 14th , 16 ) in every pressure line ( 13th ) is arranged.
• Embodiment 12:
  • Brake system according to one of the exemplary embodiments 4 to 11, characterized in that the valve ( 14th , 16 ) is a 2/2-way valve.
• Embodiment 13:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the piston-cylinder system has a first and a second piston ( 1a , 1b ), which are arranged axially displaceably in a cylinder, the first piston ( 1a ) mechanically with the electromotive drive device ( 7a , 6th , 5c ) and the second piston ( 1b ) hydraulically with the first piston ( 1a ) is coupled, whereby the two pistons ( 1a , 1b ) between them a work space ( 4a ' ), which is connected via at least one pressure line ( 13a ) is connected to at least one brake cylinder, and the second piston ( 1b ) with the cylinder a second working space ( 4b ' ) forms, which via at least one further pressure line ( 13th ) is connected to at least one other brake cylinder.
• Embodiment 14:
  • Brake system according to embodiment 13, characterized in that in the pressure lines ( 13th , 13a ) valves controlled by the control and regulation device 14th , 15th , 14a , 15a ), in particular 2/2-way valves, are arranged.
• Embodiment 15:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that when generating the brake booster, the actuating device is not or not in direct mechanical connection with the piston or the drive device, and the piston is only mechanically connected if the drive device fails or the ABS is activated Connection to the actuator is.
• Embodiment 16:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that two piston-cylinder systems, each with an associated drive device, are arranged next to one another, in particular parallel to one another, the actuating device ( 30th ) adjusts at least one of the two pistons directly or via intermediary means in the event of failure of at least one drive device.
• Embodiment 17:
  • Brake system according to embodiment 16, characterized in that the actuating device is a lever or the pivot point of a rocker ( 26th ) parallel to the adjustment path of the pistons ( 1 ) of the piston-cylinder systems adjusted, and each free end of an arm of the rocker ( 26th ) one piston each ( 1 ) assigned.
• Embodiment 18:
  • Brake system according to embodiment 17, characterized in that a limiting element ( 33 ) the swivel range of the rocker ( 26th ) limited.
• Embodiment 19:
  • Brake system according to one of the exemplary embodiments 16 to 18, characterized in that the rocker ( 26th ) on a piston ( 34 ), which is mounted in a cylinder parallel to the pistons driven by the drives ( 1 ) is slidably mounted, whereby the piston ( 34 ) by means of at least one, in particular non-linear spring ( 36 , 36a ) is pressurized in the direction of the brake pedal, and the spring together with the piston forms a so-called travel simulator, and a sensor determines the position of the piston.
• Embodiment 20:
  • Brake system according to embodiment 19, characterized in that the piston stroke of the rocker ( 26th ) connected piston ( 34 ) is limited by a stop, the stop being able to be switched off via an in particular electromagnetic actuating device.
• Embodiment 21:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that a channel defines the working space ( 4 ' ) the piston-cylinder unit with a reservoir ( 18th ) connects, with the piston ( 1 ) the channel ( 20th ) closes when entering the cylinder and the channel ( 20th ) in the starting position, i.e. only when the piston is almost or completely retracted ( 1 ) is open.
• Embodiment 22:
  • Brake system according to embodiment 21, characterized in that a shut-off valve, in particular a 2/2-way valve ( 19th ) in the channel ( 20th ) is arranged.
• Embodiment 23
  • Brake system according to exemplary embodiment 22, characterized in that the seal of the piston does not sniff any liquid in the working space as a result of a vacuum when the piston is returned quickly from the reservoir.
• Embodiment 24:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the drive is a toothed rack ( 5a ) which drives parallel to the adjustment path of the piston ( 1 ), in particular next to the piston, is displaceably mounted and in particular with low friction, the rack via a coupling element ( 5 ) with the piston ( 1 ) in particular is firmly connected.
• Embodiment 25:
  • Brake system according to the embodiment 16 , characterized in that a spring ( 9 ) the coupling link or the rack is pressurized.
• Embodiment 26:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the control regulates a corresponding brake booster as a function of the movement and / or application of force to the brake pedal and / or the driving state and / or braking effect of an electrical machine.
• Embodiment 27:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the controller determines the brake pressure in the working chamber of the cylinder from the drive current of the drive.
• Embodiment 28:
  • Brake system according to one of the preceding exemplary embodiments 1 to 16, characterized in that a pressure sensor is provided for determining the brake pressure in the working space of the cylinder.
• Embodiment 29:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the control and regulating device has a memory in which a characteristic diagram with various parameters for controlling the drive is stored.
• Embodiment 30:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the controller determines the piston position by means of at least one sensor, in particular an incremental encoder of the electric motor.
• Embodiment 31:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the drive moves the piston out of the cylinder so that it comes into mechanical contact with the brake pedal and exerts a force on the brake pedal.
• Embodiment 32:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the control for generating a rapid pressure reduction in the wheel brake generates a negative pressure by means of the associated piston by enlarging the working space before the respective valve is opened.
• Embodiment 33:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the control and regulating device energizes the electric motor of the drive device with approximately 120% of the previous blocking pressure in the control cycle before the respective valve is opened.
• Embodiment 34:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that fast energy stores are provided for storing electrical energy, in particular capacitors with a large capacity, for generating pulse currents.
• Embodiment 35:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that an additional drive adjusts the actuating device or the stop of the travel simulator in such a way that the actuating device is not mechanically connected to the piston in normal operation.
• Embodiment 36:
  • Brake system according to embodiment 35, characterized in that the additional drive acts on a travel simulator, with the additional drive moving the travel simulator back into the starting position during the pressure reduction when the locking pressure is low, so that the actuating device is not mechanically connected to the piston.
• Embodiment 37:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the control and regulating device pre-excites the valve to close it quickly, so that the valve closes immediately through a small increase in excitation.
• Embodiment 38:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the drive device has at least one piston rocker ( 60 , 61 ), by means of which the piston can be adjusted.
• Embodiment 39:
  • Brake system according to embodiment 38, characterized in that the piston rocker is a double-armed crank rocker ( 60 , 60a ) is.
• Embodiment 40:
  • Brake system according to embodiment 38 or 39, characterized in that the transmission is an encapsulated transmission and is in particular embedded in the motor housing.
• Embodiment 41:
  • Brake system according to one of the exemplary embodiments 1 to 37, characterized in that the piston is driven by means of a spindle drive arranged inside the rotor of an electric motor.
• Embodiment 42:
  • Brake system according to embodiment 41, characterized in that the rotor drives the piston via a nut which is axially displaceably mounted in the rotor, the nut being held in the axial position when the rotor rotates via a lever operated in particular by means of an electromagnet or centrifugal force, and in the event of failure of the electrical Drive the spindle together with the nut is axially displaceable in the rotor.
• Embodiment 43:
  • Brake system according to embodiment 41 or 42, characterized in that the spindle is secured against rotation by means of two bearing pins outside the piston, which at the same time accommodate the piston return springs.
• Embodiment 44:
  • Brake system according to one of the exemplary embodiments 41 to 43, characterized in that a torsion spring resets the motor.
• Embodiment 45:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that the brake system regulates a gain proportional to the pedal force, the brake system determining the pedal force on the piston.
• Embodiment 46:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that a damping element, in particular in the form of a leaf spring, is arranged between the actuating device and the respective piston, the leaf spring in particular on the rocker ( 26th ) is arranged, and that a force and / or displacement sensor for pedal force measurement is arranged on the rocker or the damping element.
• Embodiment 47:
  • Brake system according to one of the preceding exemplary embodiments, characterized in that a duct opens the working space ( 1' ) connects to the reservoir, in which a safety valve ( 80 ) is arranged, which opens in the event of a jammed piston and the working space ( 1' ) to reduce pressure in the working area with the reservoir ( 18th ) connects.
• Embodiment 48:
  • Brake system according to embodiment 47, characterized in that the safety valve is a mechanical-hydraulic or an electromagnetic valve.

Claims (27)

Brake system, having an actuating device, namely a brake pedal, and a control and regulating device, wherein the control and regulating device controls an electromotive drive device based on the movement and / or position of the actuating device, the drive device adjusting a piston of a piston-cylinder system via a non-hydraulic transmission device, so that a pressure is established in the working space of the cylinder, the working space being connected to wheel brakes, in particular to two or four wheel brakes, via a pressure line or several pressure lines, with sensors and a travel simulator being provided in order to regulate a variable pedal characteristic, an assignment of the pressure to a pedal force is freely variable and, in the case of regenerative braking by means of a generator, takes place taking into account a correction value, so that the braking effect of the generator is taken into account, wherein the drive device of the brake system is a brushless electric motor, in which, taking into account a determination of the position of the piston and a current measurement, three strands are controlled by means of a microcontroller. Brake system after Claim 1 , characterized in that a sensor device determines the position of the actuating device. Brake system according to one of the Claims 1 or 2 , characterized in that valves (14, 16) controlled by the control and regulating device (22) are arranged in the pressure line (13) to the wheel brakes (15, 17). Brake system after Claim 3 , characterized in that a valve (14, 16) assigned to a wheel brake closes after reaching the required brake pressure in a brake cylinder (15, 17) of the respective wheel brake and is opened to set a new brake pressure. Brake system after Claim 3 or 4th , characterized in that the valves 2/2 comprise solenoid valves which are controlled via a PWM method in order to bring a magnet armature of the respective valve into an intermediate position in order to generate a throttling effect. Brake system according to one of the Claims 1 to 5 , characterized in that the brake system comprises two pistons with associated electric motors and gears for two brake circuits and four wheel brakes. Brake system according to one of the Claims 1 to 5 , characterized in that a spring (9) acts on the piston (1) or the drive device, the spring force acting in the direction that the working space is enlarged. Brake system according to one of the Claims 1 to 5 , 7th , characterized in that the drive device has at least one electric motor (8) with, in particular, a small time constant and / or a high acceleration capacity, the electric motor (8) being an electric motor controlled by output stages (21) via three strands of a microcontroller (MC). Brake system after Claim 8 , characterized in that the electric motor (8) is energized with a closed valve (14, 16) with an excitation current which is sufficient to hold the piston (1) in position against the spring force. Brake system according to one of the preceding claims, characterized in that each brake circuit has a piston-cylinder system. Brake system according to one of the preceding claims, characterized in that the working space (4 ') is connected to several brake cylinders (15, 17) via two or more pressure lines (13), with one valve (14, 16) in each pressure line ( 13) is arranged. Brake system according to one of the Claims 3 to 11 , characterized in that the valve (14, 16) is a 2/2-way valve. Brake system according to one of the preceding claims, characterized in that when generating the brake force boost, the actuating device is not or not in direct mechanical connection with the piston or the drive device, and the piston is only in mechanical connection with the actuation device if the drive device fails. Brake system according to one of the preceding claims, characterized in that a channel connects the working space (4 ') of the piston-cylinder unit with a reservoir (18), the piston (1) closing the channel (20) when entering the cylinder and the Channel (20) is open in the starting position, ie only when the piston (1) is almost or completely retracted. Brake system after Claim 14 , characterized in that a shut-off valve, in particular a 2/2-way valve (19) is arranged in the channel (20). Brake system according to one of the preceding claims, characterized in that the control regulates a corresponding brake force boost as a function of the movement and / or application of force to the brake pedal and / or the driving state and / or braking effect of an electrical machine. Brake system according to one of the preceding claims, characterized in that the control determines the brake pressure in the working chamber of the cylinder from the drive current of the drive. Brake system according to one of the Claims 1 to 16 , characterized in that a pressure sensor is provided for determining the brake pressure in the working space of the cylinder. Brake system according to one of the preceding claims, characterized in that the control and regulating device has a memory in which a map with various parameters for controlling the drive is stored. Brake system after a Claim 19 , characterized in that the map, different current strengths position of the piston and / or wherein an output map is formed from preferably pressure-volume characteristic of the wheel brake, engine parameter, transmission efficiency and vehicle deceleration. Brake system according to one of the Claims 19 or 20th , characterized in that the map is adapted during operation. Brake system according to one of the preceding claims, characterized in that the control determines the piston position by means of at least one sensor. Brake system according to one of the preceding claims, characterized in that fast energy stores are provided for storing electrical energy, in particular capacitors with a large capacity, for generating pulse currents. Brake system according to one of the preceding claims, characterized in that the piston is driven by means of a spindle drive arranged within the rotor of an electric motor. Brake system according to one of the preceding claims, characterized in that the brake system regulates a gain proportional to the pedal force, the brake system determining the pedal force on the piston. Brake system according to one of the preceding claims, characterized in that a channel connects the working space (1 ') with the reservoir, in which a safety valve (80) is arranged, which opens in the event of a jammed piston and the working space (1') for pressure reduction connects in the working space with the reservoir (18). Brake system after Claim 26 , characterized in that the safety valve is a mechanical-hydraulic or an electromagnetic valve.

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