JP4462038B2 - Brake hydraulic pressure control device - Google Patents

Description

  The present invention relates to a brake fluid pressure control device that pressurizes an assist fluid pressure formed by controlling a fluid pressure discharged from a pump with a fluid pressure control valve to a master cylinder fluid pressure generated by a master cylinder in accordance with a brake operation force. It is about.

  In the vehicle deceleration feedback electronic control brake device described in Patent Document 1 shown below, the initial vehicle deceleration G0 at the start of the brake operation is detected, and the control target addition amount Gadd is based on the operation input amount C of the driver. Is set, the control target addition amount Gadd is added to the initial vehicle deceleration G0 to set the control target amount Gt, and the difference between the vehicle deceleration G detected by the vehicle deceleration detector 41 and the control target amount Gt is calculated. Feedback to the control command output unit 45, the drive circuit 5 controls each actuator A1 to A4 connected to the hydraulic pressure source 6 based on the control command signal D from the control command output unit 45, to the brake device of each wheel The supplied hydraulic pressure is controlled.

  Further, the brake for the vehicle generates a master cylinder hydraulic pressure by the force obtained by boosting the brake operating force by the negative pressure assist device, and applies the master cylinder hydraulic pressure to the wheel cylinders of the respective wheels connected to the master cylinder. In the device, the negative pressure type assisting device cannot boost the brake operating force by the boost ratio when the boost limit point is exceeded, and boosts the brake operating force at the boost limit point by the boost ratio. A force obtained by adding an increment of the brake operation force after the limit point is output, and the master cylinder generates a master cylinder hydraulic pressure by this force.

Accordingly, in the vehicle brake device that boosts the brake operation force with the negative pressure assist device, the vehicle deceleration is fed back to control the brake hydraulic pressure supplied to each actuator A1 to A4 as described in Patent Document 1. When trying to do so, it is preferable to control the brake hydraulic pressure in which the brake operation force is increased at the same ratio before and after the boost limit point based on the control command signal D from the control command output unit 45. For this purpose, the assist hydraulic pressure formed by controlling the hydraulic pressure discharged from the pump with a hydraulic pressure control valve connected between the master cylinder and the wheel cylinder is increased to the master cylinder hydraulic pressure. Yes.
JP-A-6-166365 (page 3, FIG. 1)

  However, the actual boost limit point of the negative pressure assist device is generally a design double due to the operating conditions of the engine that is the source of the negative pressure, the tolerance in the production of the negative pressure assist device, the secular change due to use, etc. It changes with respect to the force limit point. Therefore, in order to obtain the brake fluid pressure that increases the brake operation force in accordance with the design boost ratio after the design boost limit point, the assist fluid pressure with respect to the brake operation force is calculated and the assist fluid pressure is calculated. When the pressure is applied to the master cylinder hydraulic pressure generated by the brake operating force after the designed boost limit point, the brake hydraulic pressure increases according to the boost ratio before and after the actual boost limit point. Can't get.

   The present invention has been made to solve the conventional problems, and after the actual boost limit point of the negative pressure assist device that boosts the brake operation force, the brake operation force is increased according to the boost ratio. A brake fluid pressure control device capable of obtaining a brake fluid pressure is provided.

In order to solve the above problems, the structural feature of the invention according to claim 1 is that the master cylinder generates a master cylinder hydraulic pressure by a force obtained by boosting the brake operating force by the negative pressure type assisting device, and the master cylinder In a vehicle brake device that applies a hydraulic pressure to a wheel cylinder of each wheel connected to the master cylinder, a hydraulic pressure control valve connected between the master cylinder and the wheel cylinder controls a discharge hydraulic pressure from a pump. Controlling to form an assist hydraulic pressure, pressurizing the assist hydraulic pressure to the master cylinder hydraulic pressure to obtain a brake hydraulic pressure, an operating force detecting means for detecting the brake operating force, and boosting limit point detecting means for negative pressure assisting device detects boost actual boost limit point no longer in power ratio of the brake operating force, the negative pressure boosting device Bradenton A storage means for preliminarily storing a design boost limit point at which the operation force is not boosted by a boost ratio, and a deviation amount between the actual boost limit point and the design boost limit point is calculated. In order to obtain a brake fluid pressure that increases the brake operation force in accordance with the boost ratio after the actual boost limit point when the shift amount exceeds a reference, when the shift amount exceeds a reference , There is provided pressurization calculation output means for calculating the assist hydraulic pressure with respect to the brake operation force, causing the hydraulic pressure generating device to form the assist hydraulic pressure and pressurizing the master cylinder hydraulic pressure.

According to a second aspect of the present invention, there is provided a structural feature of the first aspect , further comprising: a hydraulic pressure detecting means for detecting the master cylinder hydraulic pressure, wherein the boost limit point detecting means is detected by the hydraulic pressure detecting means. The ratio between the master cylinder hydraulic pressure and the brake operation force detected by the operation force detection means is sequentially calculated, and the actual boost limit point is detected when the ratio decreases from the previous time.

According to a third aspect of the present invention, there is provided a structural feature of the first aspect, further comprising: deceleration detection means for detecting vehicle deceleration, wherein the boost limit point detection means is detected by the deceleration detection means. A ratio between the vehicle deceleration and the brake operation force detected by the operation force detector is sequentially calculated, and the actual boost limit point is detected when the ratio is lower than the previous time.

According to a fourth aspect of the present invention, there is provided a structural feature according to any one of the first to third aspects, wherein the storage means increases the brake operating force by a design double after a design boost limit point. The assist hydraulic pressure for obtaining the brake hydraulic pressure increased according to the force ratio is stored in advance, and the pressurization calculation output means is configured to calculate the boost limit point on the design and the actual boost limit point. Based on the amount of deviation and the assist hydraulic pressure with respect to the brake operating force stored in the storage means, the brake hydraulic pressure in which the brake operating force is increased in accordance with the boost ratio after the actual boost limit point is obtained. For this purpose, an assist hydraulic pressure with respect to the brake operation force is calculated, and the assist hydraulic pressure is formed in the hydraulic pressure generating device to increase the master cylinder hydraulic pressure.

According to a fifth aspect of the present invention, in any one of the first to third aspects, the pressurization calculation output means includes a master cylinder hydraulic pressure detected by the hydraulic pressure detection means and the operation. In order to obtain a ratio of the brake operation force detected by the force detection means and to obtain a brake fluid pressure in which the brake operation force is increased by the ratio after the actual boost limit point, the assist fluid with respect to the brake operation force is obtained. The pressure is calculated, and the hydraulic pressure generating device forms the assist hydraulic pressure and pressurizes the master cylinder hydraulic pressure.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the master cylinder hydraulic pressure at the actual boost limit point detected by the boost limit point detecting means is determined in advance. When the pressure is lower than the set control-permitted hydraulic pressure, a prohibiting means for prohibiting the operation of the pressurization calculation output means is provided.

In the invention according to claim 1 configured as described above, the master cylinder generates the master cylinder hydraulic pressure by the force obtained by boosting the brake operation force by the negative pressure type assisting device, and the hydraulic pressure generating device discharges liquid from the pump. The pressure is controlled by a hydraulic pressure control valve connected between the master cylinder and the wheel cylinder to increase the assist hydraulic pressure to the master cylinder hydraulic pressure. The actual boost limit point at which the negative pressure assist device does not boost the brake operating force at the boost ratio is detected by the boost limit point detection means, and this actual boost limit point and the designed boost limit point are Only when the amount of deviation exceeds the standard, after the actual boost limit point, to obtain the brake fluid pressure that increases the brake operation force according to the boost ratio, calculate the assist fluid pressure against the brake operation force The assist hydraulic pressure is increased by the hydraulic pressure generator to the master cylinder hydraulic pressure generated by the brake operation force.

As a result, the brake operating force and the master cylinder hydraulic pressure after the actual boost limit point of the negative pressure assist device are subject to the operating conditions of the engine that is the source of the negative pressure, manufacturing tolerances of the negative pressure assist device, and aging due to use. due to changes, even if offset relative boost limit point of the design, it is possible in actual boost limit point later, to obtain an increased brake fluid pressure in accordance with power ratio of the brake operating force.
Only when the deviation between the actual boost limit point detected by the boost limit point detection means and the designed boost limit point exceeds the standard, the brake operation force after the actual boost limit point is exceeded. In order to obtain an increased brake fluid pressure according to the boost ratio, the assist fluid pressure with respect to the brake operation force is calculated, and the assist fluid pressure is added to the master cylinder fluid pressure generated by the brake operation force by the fluid pressure generator. Since pressure is applied, control is simplified and responsiveness is improved.

In the invention according to claim 2 configured as described above, when the ratio between the master cylinder hydraulic pressure detected by the hydraulic pressure detecting means and the brake operating force detected by the operating force detecting means is lower than the previous time, it is negative. Since the pressure assist device detects the actual boost limit point at which the brake operation force is not boosted by the boost ratio, the actual boost limit point can be detected with a simple configuration.

In the invention according to claim 3 configured as described above, when the ratio between the vehicle deceleration detected by the deceleration detecting means and the brake operating force detected by the operating force detecting means is lower than the previous time, the negative pressure type Since the assist device detects the actual boost limit point at which the brake operation force is not boosted by the boost ratio, the actual boost limit point can be detected with a simple configuration.

In the invention according to claim 4 configured as described above, the assist hydraulic pressure for obtaining the brake hydraulic pressure in which the brake operation force is increased in accordance with the designed boost ratio after the designed boost limit point. Is previously stored in the storage means. Based on the amount of deviation between the designed boost limit point and the actual boost limit point and the assist hydraulic pressure stored in the storage means, the brake operating force is increased to the boost ratio after the actual boost limit point. In order to obtain the brake fluid pressure increased according to the pressure, the assist fluid pressure is calculated with respect to the brake operation force, and the assist fluid pressure is increased to the master cylinder fluid pressure. Thus, the increased brake fluid pressure can be obtained with a simple means and with good responsiveness.

In the invention according to claim 5 configured as described above, a ratio between the master cylinder hydraulic pressure detected by the hydraulic pressure detecting means and the brake operating force detected by the operating force detecting means is obtained, and an actual boost limit is obtained. After that, in order to obtain a brake fluid pressure that increases the brake operation force by this ratio, an assist fluid pressure is calculated with respect to the brake operation force, and the assist fluid pressure is added to the master cylinder fluid pressure generated by the brake operation force. Therefore, even if the ratio deviates from the designed boost ratio, the brake hydraulic pressure can be increased at the same ratio with respect to the brake operating force before and after the boost limit point.

In the invention according to claim 6 configured as described above, when the master cylinder hydraulic pressure corresponding to the actual boost limit detected by the boost limit detecting means is lower than the preset control permission hydraulic pressure. Since the pressurization calculation output means is not operated, the hydraulic pressure generating device pressurizes the assist hydraulic pressure corresponding to the brake operation force to the master cylinder hydraulic pressure even though the negative pressure assist device is abnormal. Can be prevented.

   Embodiments of a brake fluid pressure control device according to the present invention will be described below with reference to the drawings. In the brake fluid pressure control device 1 for a vehicle brake device, a front-wheel brake system having substantially the same configuration that applies a braking force to the left and right front wheels 3fl and 3fr and the left and right rear wheels 3rl and 3rr when the driver steps on the brake pedal 2. 4f and the rear wheel brake system 4r are provided separately. In FIG. 1, the components constituting the front wheel and rear wheel brake systems 4f and 4r have the same configuration and operation, so that the corresponding components are given the same arithmetic numerals with Roman letters f and r, respectively. A reference symbol is assigned to distinguish between the front and rear. Furthermore, the same component parts in the left and right wheels are distinguished from each other by adding l and r after Roman letters f and r that distinguish the front and rear wheels. In the specification, when components are shown without distinction between front, back, left, and right, only the corresponding arithmetic numbers are given as reference numbers.

   Reference numeral 5 denotes a dual master cylinder. When the brake pedal 2 is depressed, the brake fluid of the master cylinder hydraulic pressure PMC corresponding to the brake operating force F is sent from the hydraulic chambers 5f and 5r for the front and rear wheels to the pipelines 6f and 6r. Reference numeral 7 denotes a vacuum booster which is a negative pressure type assisting device interposed between an operating rod axially moved by the brake pedal 2 and a piston rod of the master cylinder 5, and applies an intake negative pressure of the engine to the diaphragm. The brake operating force F acting on the brake pedal 2 is boosted. Reference numeral 8 denotes a reservoir for storing brake fluid, which replenishes the dual master cylinder 5 with brake fluid. As shown in FIG. 2, before the boost limit point D at which the valve mechanism is fully opened, the brake booster 7 boosts the brake operating force F at a predetermined boost ratio according to the valve opening of the valve mechanism of the brake booster 7. The master cylinder hydraulic pressure PMC is generated in the master cylinder 5 by the applied force, and after the boost limit point D, the brake operation force F after the boost limit point D is increased to the master cylinder hydraulic pressure PMC at the boost limit point D. The master cylinder hydraulic pressure PMC obtained by adding the increase in the master cylinder hydraulic pressure PMC by the minute is generated in the master cylinder 5.

   Thus, the master cylinder 5 generates the master cylinder hydraulic pressure PMC by the force boosted by the vacuum booster 7, and the hydraulic pressure sent from the master cylinder 5 is transmitted to the left and right wheel braking devices 9fl, 6f, 6r. 9fr, 9rl, and 9rr are supplied to the wheel cylinders 10fl, 10fr, 10rl, and 10rr, respectively. The left and right wheel braking devices 9fl, 9fr, 9rl, and 9rr have pistons that act as brake pads, brake shoes, and other friction members such as brake discs, brake drums, etc. by brake hydraulic pressure PWC supplied to the wheel cylinders 10fl, 10fr, 10rl, and 10rr. A braking force is generated on the left and right front and rear wheels 3fl, 3fr, 3rl, 3rr by being brought into pressure contact with each other.

   12f and 12r are solenoid hydraulic pressure proportional control valves that form hydraulic pressure control valves, and their inlet ports and outlet ports are connected to the hydraulic chambers 5f and 5r of the master cylinder 5 and to the wheel cylinders 10fl, 10fr and 10rl and 10rr with pipe lines 6f, 6r is connected to each other. The solenoid hydraulic pressure proportional control valve 12 controls the pressure so that the hydraulic pressure at the outlet port is higher than zero by the assist hydraulic pressure PA in accordance with the control current applied to the linear solenoid 14 from the master cylinder hydraulic pressure at the inlet port. is there. A check valve that allows liquid flow from the inlet port to the outlet port is connected between the inlet port and the outlet port of the solenoid hydraulic pressure proportional control valves 12f and 12r.

   The pipelines 6f and 6r connected to the outlets of the solenoid hydraulic pressure proportional control valves 12f and 12r are branched to the left and right front wheel cylinders 10fl and 10fr and the left and right rear wheel cylinders 10rl and 10rr, and the solenoid on-off valve 17fl. , 17fr and 17rl, 17rr, respectively. A check valve that allows liquid flow from the out-port side to the import side is connected between the import and out-ports of the solenoid on-off valves 17fl, 17fr, 17rl, and 17rr. Solenoid on-off valves 19fl, 19fr and 19rl, 19rr are connected between the respective outports of the solenoid on-off valves 17fl, 17fr and 17rl, 17rr and the reservoirs 18f and 18r, respectively. The reservoirs 18f and 18r are configured by sealing a bottomed casing with a piston urged by a weak compression spring. The solenoid valve 17 and 19 constitutes an ABS valve device 20 that increases, holds, and controls the pressure in the wheel cylinder 10, and the import / outport of the solenoid valve 17 serves as the import / outport of the ABS valve device 20. None, the out port of the solenoid opening / closing valve 19 is the discharge port of the ABS valve device 20.

   21f and 21r are hydraulic pressure pumps that are driven to rotate by the motor 22, and the outlets of the solenoid hydraulic pressure proportional control valves 12f and 12r have their discharge ports blocked by check valves 13f and 13r that block the liquid flow to the discharge ports. The intake port is connected to the inlet port of the solenoid hydraulic pressure proportional control valves 12f and 12r via the electromagnetic open / close valves 23f and 23r. The suction ports of the hydraulic pumps 21f and 21r are also connected between the discharge ports of the ABS valve devices 20f and 20r and the reservoirs 18f and 18r via check valves 15f and 15r that allow liquid flow to the suction ports. ing. 24f and 24r are dampers for absorbing the pulsation of the hydraulic pressure discharged from the hydraulic pumps 21f and 21r.

   Thus, the discharge liquid discharged from the pump 21 that is rotationally driven by the motor 22 with the electromagnetic on-off valve 23 switched to the open state is circulated through the solenoid hydraulic pressure proportional control valve 12 and the electromagnetic on-off valve 23. As a result, an assist hydraulic pressure PA corresponding to the control current applied to the linear solenoid 14 is generated, and the assist hydraulic pressure PA is pressurized to the master cylinder hydraulic pressure PMC to become the brake hydraulic pressure PWC. Is supplied to the wheel cylinder 10.

   The hydraulic pressure control valve 12 (liquid pressure) is connected between the master cylinder 5 and the wheel cylinder 10 by the motor 22, the pump 21, the solenoid hydraulic pressure proportional control valve 12, the electromagnetic on-off valve 23 and the like. The hydraulic pressure generating device 32 is configured to form the assist hydraulic pressure PA by being controlled by the pressure control valve) and to apply the assist hydraulic pressure PA to the master cylinder hydraulic pressure PMC to obtain the brake hydraulic pressure PWC. Hydraulic pressure generating devices 32f and 32r are provided for each of the front wheel brake system 4f and the rear wheel brake system 4r.

   The electronic control unit 25 incorporating the CPU of the brake fluid pressure control device 1 includes a wheel speed sensor 26 that detects the wheel speed of each wheel 3, a foot brake sensor 27 that detects the depression of the brake pedal 2, and a master cylinder fluid pressure PMC. Detection signals are input from the hydraulic pressure sensor 16 that detects the braking force and the operating force sensor 28 that detects the brake operating force F. The operation force sensor 28 that constitutes an operation force detection means is configured by connecting a force sensor that detects a depression force (brake operation force F) of the brake pedal 2 to the brake pedal 2. The vehicle speed detecting means 29 provided in the electronic control unit 25 counts a pulse with a frequency proportional to the wheel rotational speed sent from the wheel speed sensor 26 mounted on the left and right non-driven wheels for a certain period and arithmetically averages. The vehicle speed V is obtained based on the value, and the deceleration detecting means 31 obtains the vehicle deceleration G by dividing the change amount of the vehicle speed V detected by the vehicle speed detecting means 29 in the minute time by the minute time.

   The electronic control unit 25 includes a wheel speed sensor 26, a foot brake sensor 27, a hydraulic pressure sensor 16, a detection signal input from the operation force sensor 28, and a vehicle speed V obtained by the vehicle speed detection means 29 and the deceleration detection means 31. Each program is executed based on the vehicle deceleration G, and a control signal is output to the solenoid hydraulic pressure proportional control valves 12r and 12f, the ABS valve devices 20f and 20r, the motor 22, the electromagnetic on-off valves 23f and 23r, etc. The braking force applied to the wheel 3 is controlled by controlling the hydraulic pressure in the wheel cylinder 10.

   As shown by a solid line in FIG. 2, after the boost limit point D0 on the design of the brake booster 7, the brake operation force F is increased according to the same boost ratio on the design as before the boost limit point D0. In order to obtain the pressure PWC, the assist hydraulic pressure PA pressurized to the master cylinder hydraulic pressure PMC generated by the brake operating force F is stored in the storage means 30 of the control device 25. The assist hydraulic pressure PA for the brake operation force F after the boost limit point D0 is stored in the storage means 30 as a map or a calculation formula. The storage means 30 also stores a brake operating force F0 and a master cylinder hydraulic pressure PMC0 at the designed boost limit point D0.

   When the brake operation force F detected by the operation force sensor 28 becomes the brake operation force F after the designed boost limit point D0, the assist hydraulic pressure PA with respect to the brake operation force F stored in the storage means 30 is obtained. Each assist hydraulic pressure PA is read from the map indicating the control pressure, a control current corresponding to each assist hydraulic pressure PA is applied to the linear solenoid 14, and the discharge hydraulic pressure from the pump 21 is controlled by the solenoid hydraulic pressure proportional control valve 12. Thus, each assist hydraulic pressure PA is pressurized to each master cylinder hydraulic pressure PMC.

  The boost limit point detection means 33 incorporated in the electronic control unit 25 is based on the brake operating force F detected by the operating force sensor 28 and the master cylinder hydraulic pressure PMC detected by the hydraulic pressure sensor 16, and the vacuum booster 7. Detects the actual boost limit point D at which the brake operating force F is not boosted at the boost ratio. The master cylinder hydraulic pressure PMC at the actual boost limit point D decreases considerably with changes in the operating conditions of the engine that is the source of negative pressure, for example, a decrease in the rotational speed, and the corresponding brake operating force F is from F0. Decrease to F1. The boost ratio slightly changes due to production tolerances of the vacuum booster 7, changes over time due to use, etc., and the brake operating force F corresponding to the actual boost limit point D slightly changes from F0 to F2, for example. Therefore, in such a case, every time the brake operation force F detected by the operation force sensor 28 becomes the brake operation force F after the design boost limit point D0 stored in the storage means 30, the memory is stored. When each assist hydraulic pressure PA stored in the means 30 is read and output to the hydraulic pressure generating device 32, the brake hydraulic pressure PWC obtained by increasing the brake operating force F after the actual boost limit point D according to the boost ratio is obtained. The wheel cylinder 10 cannot be supplied.

  Therefore, the pressurization calculation output means 34 incorporated in the electronic control unit 25 reads a map indicating each assist hydraulic pressure PA with respect to each brake operation force F after the design boost limit point D0, and the design boost. Each brake operation force after the actual boost limit point D is shifted by shifting each brake operation force F with respect to each assist hydraulic pressure PA by the difference in brake operation force between the limit point D0 and the actual boost limit point D. Each assist hydraulic pressure PA for F is calculated. Each time the brake operation force F detected by the operation force sensor 28 becomes the brake operation force F after the actual boost limit point D, the calculated assist hydraulic pressure PA is supplied from the hydraulic pressure generator 32. The brake hydraulic pressure PWC that is output and increases the brake operation force F after the actual boost limit point D according to the boost ratio is supplied to the wheel cylinder 10.

   Next, the operation of the brake fluid pressure control apparatus 1 according to the above embodiment will be described. The master cylinder hydraulic pressure PMC sent from the pressure chambers 5f and 5r of the master cylinder 5 when the brake pedal 2 is depressed passes through the solenoid hydraulic pressure proportional control valves 12f and 12r and the solenoid on-off valve 17 shifted to the open position. Are supplied to each wheel cylinder 10 and a braking force is applied to each wheel 3. At this time, when the condition for requesting the anti-skid brake control is established, the electronic control unit 25 performs the anti-skid brake control to open and close the solenoid on-off valves 17 and 19 to control the hydraulic pressure in each wheel cylinder 10. The braking force applied to each wheel is increased, held and decreased so that the wheel 3 does not slip with respect to the road surface.

   When the depression of the brake pedal 2 is detected by the foot brake sensor 27, the hydraulic pump 21 is rotationally driven by the motor 22, and the electronic control unit 25 executes the brake hydraulic pressure control program shown in FIG. 3 at regular minute intervals. When the master cylinder hydraulic pressure PMC and the brake operating force F detected by the hydraulic pressure sensor 16 and the operating force sensor 28 are acquired in step S1, and the master cylinder hydraulic pressure PMC is lower than the preset control permission hydraulic pressure L, Since the master cylinder hydraulic pressure is too low to operate the pressurization calculation output means 34, the program ends (step S2).

   When the master cylinder hydraulic pressure PMC exceeds the control permission hydraulic pressure L, the electronic control unit 25 compares the ratio between the master cylinder hydraulic pressure PMC detected by the hydraulic pressure sensor 16 and the brake operating force F detected by the operating force sensor 28. Are sequentially calculated, and when this ratio decreases from the previous time, the actual boost limit point D is detected (step S3). If not, the program ends. The hydraulic pressure sensor 16 and step 3 constitute boost limit point detection means 33. When the master cylinder hydraulic pressure PMC corresponding to the actual boost limit point D detected by the boost limit point detection means 33 is lower than the control permission hydraulic pressure L, the operation of the pressurization calculation output means 34 is prohibited. The prohibiting means 35 is configured by Step 2 and Step S3.

   When the boost limit point detecting means 33 detects the actual boost limit point D, the electronic control unit 25 stores the actual boost limit point D and the storage means 30 in step S4 which constitutes the deviation amount calculating means. A deviation E from the design boost limit point D0 is calculated, and it is determined in step S5 whether or not the deviation is within the design standard. If it is within the reference, the pressure calculation output means 34 of the electronic control unit 25 reads each assist hydraulic pressure PA for each brake operation force F after the designed boost limit point D0 from the storage means 30 (step S6). ) Each time the brake operation force F detected by the operation force sensor 28 becomes each brake operation force F after the boost limit point D0, each assist hydraulic pressure PA for each brake operation force F is output, and each assist fluid A control current corresponding to the pressure PA is applied to the linear solenoid 14 (step S7).

  When the deviation amount E exceeds the design standard, the pressurization calculation output means 34 reads each assist hydraulic pressure PA for each brake operation force F after the designed boost limit point D0 from the storage means 30, and actually After the boost limit point D, in order to obtain the brake fluid pressure PWC in which the brake operation force F is increased in accordance with the designed boost ratio, the design boost limit point D0 and the actual boost limit point D Each assist hydraulic pressure PA for each brake operating force F after the actual boost limit point D is calculated on the basis of the amount of deviation E and each assist hydraulic pressure PA for each brake operating force F read from the storage means 30. (Step S8). For example, each brake operation force F after the design boost limit point D0 is shifted with respect to each assist hydraulic pressure PA by the difference in the brake operation force between the design boost limit point D0 and the actual boost limit point D. Good. Each time the brake operation force F detected by the operation force sensor 28 becomes each brake operation force F after the actual boost limit point D, each assist hydraulic pressure PA with respect to each brake operation force F is output. A control current corresponding to the assist hydraulic pressure PA is applied to the linear solenoid 14 (step S7). Thereby, the discharge hydraulic pressure from the pump 21 is controlled by the solenoid hydraulic pressure proportional control valve 12 so that each assist hydraulic pressure PA is pressurized to each master cylinder hydraulic pressure PMC, and the brake operation is performed after the actual boost limit point. The brake fluid pressure PWC in which the force F is increased according to the boost ratio can be supplied to the wheel cylinder.

   When the depression of the brake pedal 2 is no longer detected by the foot brake sensor 27, the hydraulic pump 22 is stopped and the execution of the brake hydraulic pressure control program is stopped.

   In the above embodiment, the actual boost limit point D is detected from the ratio between the master cylinder hydraulic pressure PMC detected by the hydraulic pressure sensor 16 and the brake operating force F detected by the operating force sensor 28. While the wheels are not locked, the vehicle deceleration G is approximately proportional to the master cylinder hydraulic pressure PMC. Therefore, the vehicle deceleration G detected by the deceleration detection means 31 and the brake operation force F detected by the operation force sensor 28 It is also possible to calculate the ratio of the first and second, and assume that the actual boost limit point D is detected when this ratio is lower than the previous ratio.

   In the above embodiment, after the designed boost limit point D0, each assist for each brake operating force F is obtained in order to obtain the brake hydraulic pressure PWC in which the brake operating force F is increased in accordance with the designed boost ratio. In order to obtain the brake hydraulic pressure PWC in which the hydraulic pressure PA is stored in advance in the storage means 30 and the brake operating force F is increased in accordance with the designed boost ratio after the actual boost limit point D, Based on the shift amount E between the boost limit point D0 and the actual boost limit point D and each assist hydraulic pressure PA for each brake operation force stored in the storage means 30, each of the actual boost limit points D and after Each assist hydraulic pressure PA with respect to the brake operation force F is calculated. However, unlike the above embodiment, the actual ratio between the master cylinder hydraulic pressure PMC detected by the hydraulic pressure sensor 16 and the brake operating force F detected by the operating force sensor 28 is obtained to determine the actual boost limit point D. The difference between each brake hydraulic pressure PWC obtained by multiplying each actual brake operation force F by the actual ratio and each master cylinder hydraulic pressure PMC generated by each brake operation force F is calculated as each assist hydraulic pressure PA. May be calculated as follows.

   In the above embodiment, when the depression of the brake pedal 2 is detected by the foot brake sensor 27, the hydraulic pump 21 is driven to rotate by the motor 22, but the master cylinder hydraulic pressure PMC is higher than the control permission hydraulic pressure L. Then, the hydraulic pump 21 may be driven.

1 is a hydraulic circuit diagram of a brake fluid pressure control device of the present embodiment. The figure which shows the master cylinder hydraulic pressure with respect to brake operation force, and brake hydraulic pressure. The figure which shows a brake fluid pressure control program.

Explanation of symbols

   DESCRIPTION OF SYMBOLS 1 ... Brake hydraulic pressure control device, 2 ... Brake pedal, 3 ... Wheel, 4 ... Brake system, 5 ... Master cylinder, 9 ... Wheel brake device, 10 ... Wheel cylinder, 12 ... Solenoid hydraulic pressure proportional control valve (hydraulic pressure control Valve), 14 ... linear solenoid, 16 ... hydraulic pressure sensor, 17, 19, 23 ... solenoid open / close valve, 21 ... hydraulic pump, 22 ... motor, 25 ... electronic control unit, 26 ... wheel speed sensor, 27 ... foot brake Sensors 28... Operation force sensor 29. Vehicle speed detection means 30. Storage means 31. Deceleration detection means 32 32 Hydraulic pressure generator 33 33 Boost limit point detection means 34 34 Pressurization calculation output means 35 ... Prohibition means, E ... Deviation amount, PMC ... Master cylinder hydraulic pressure, PA ... Assist hydraulic pressure, F ... Brake operating force, PWC ... Brake hydraulic pressure.

Claims (6)

A brake device for a vehicle in which a master cylinder generates a master cylinder hydraulic pressure by a force obtained by boosting a brake operating force by a negative pressure type assisting device, and applies the master cylinder hydraulic pressure to a wheel cylinder of each wheel connected to the master cylinder. In
The hydraulic pressure discharged from the pump is controlled by a hydraulic pressure control valve connected between the master cylinder and the wheel cylinder to form an assist hydraulic pressure, and the assist hydraulic pressure is increased to the master cylinder hydraulic pressure. A hydraulic pressure generator for obtaining brake hydraulic pressure,
Operating force detecting means for detecting the brake operating force;
A boost limit point detecting means for detecting an actual boost limit point at which the negative pressure assist device does not boost the brake operating force at a boost ratio;
Storage means for preliminarily storing a design boost limit point at which the negative pressure assist device does not boost the brake operation force at a boost ratio;
A deviation amount calculating means for calculating a deviation amount between the actual boost limit point and the designed boost limit point;
In order to obtain the brake fluid pressure that increases the brake operation force according to the boost ratio after the actual boost limit point when the deviation amount exceeds a reference, the assist fluid with respect to the brake operation force A brake hydraulic pressure control device comprising: a pressure calculation output means for calculating a pressure and causing the hydraulic pressure generating device to form the assist hydraulic pressure and pressurizing the master cylinder hydraulic pressure. 2. The pressure detection means according to claim 1 , further comprising a hydraulic pressure detecting means for detecting the master cylinder hydraulic pressure, wherein the boost limit point detecting means is detected by the master cylinder hydraulic pressure detected by the hydraulic pressure detecting means and the operating force detecting means. A brake hydraulic pressure control device that sequentially calculates a ratio with a brake operating force to be detected, and detects the actual boost limit point when the ratio decreases from the previous time. 2. The vehicle according to claim 1 , further comprising deceleration detecting means for detecting vehicle deceleration, wherein the boost limit point detecting means is a vehicle deceleration detected by the deceleration detecting means and a brake detected by the operating force detecting means. A brake fluid pressure control device that sequentially calculates a ratio with an operating force and detects the actual boost limit point when the ratio decreases from the previous time. In any one of claims 1 to 3, wherein the storage means is the boosting limit point later in the design, for obtaining an increased brake fluid pressure in accordance with boosting ratio of the design the brake operating force The assist hydraulic pressure is stored in advance, and the pressurization calculation output means is configured so that a deviation amount between the designed boost limit point and the actual boost limit point and the brake operation force stored in the storage means are stored. On the basis of the assist hydraulic pressure with respect to the vehicle, the assist hydraulic pressure with respect to the brake operating force is calculated in order to obtain the brake hydraulic pressure with the brake operating force increased according to the boost ratio after the actual boost limit point. A brake fluid pressure control device that causes the fluid pressure generating device to form the assist fluid pressure and pressurize the master cylinder fluid pressure. The pressurization calculation output means according to any one of claims 1 to 3 , wherein a ratio between a master cylinder hydraulic pressure detected by the hydraulic pressure detection means and a brake operating force detected by the operating force detection means. In order to obtain a brake fluid pressure obtained by increasing the brake operation force by the ratio after the actual boost limit point, an assist fluid pressure with respect to the brake operation force is calculated, and the assist fluid is supplied to the fluid pressure generator. A brake fluid pressure control device characterized in that a pressure is formed to increase the master cylinder fluid pressure. 6. When the master cylinder hydraulic pressure at the actual boost limit point detected by the boost limit point detecting means is lower than a preset control permission hydraulic pressure in any one of claims 1 to 5 , A brake fluid pressure control device comprising a prohibiting means for prohibiting the operation of the pressure calculation output means.

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