JP2005319848A - Brake system - Google Patents

Abstract

A brake system capable of easily recognizing a change in operability of a service brake in a vehicle equipped with a service hydraulic brake and an electric parking brake.
EPB14 is released using a pressure greater than a predetermined value obtained from a part of hydraulic piping of a service hydraulic brake. In this case, when the hydraulic pressure or the like due to the normal operation of the service hydraulic brake 12 is reduced and the operability is changed, a clear phenomenon appears that it becomes difficult to release the EPB 14, and the driver must start before starting the vehicle. It is possible to recognize changes in the function of the regular hydraulic brake.
[Selection] Figure 1

Description

  The present invention relates to a brake system, and in particular, a brake system capable of easily recognizing changes in operability of a service brake in a vehicle brake system equipped with a service hydraulic brake operated by operating a brake pedal and an electric parking brake. Regarding improvements.

  2. Description of the Related Art Conventionally, a vehicle brake device is equipped with a service hydraulic brake that uses hydraulic pressure so that smooth and safe braking can be performed. For example, a disc brake or a drum brake is used as the regular hydraulic brake. These brake systems operate a master cylinder when a driver depresses a brake pedal, and a predetermined pressure is transmitted to a cylinder in a wheel of a disc brake or a drum brake to generate a braking force.

  On the other hand, the vehicle is equipped with a parking brake in addition to the regular hydraulic brake. The simplest type of parking brake is to drive a wire by pulling an operation lever to operate a brake pad and brake a wheel. Some parking brakes of this type can release the parking brake by depressing the brake pedal of the service hydraulic brake, simplifying the operability and releasing the parking brake. There is one that provides a structure that prevents creep start or sudden start by operating (see, for example, Patent Document 1).

Recently, an electric parking brake (EPB) has been proposed in which a motor or the like is driven by pressing an operation switch or the like to wind or unwind a wire and switch between a braking state and a non-braking state. In this case, the parking brake can be easily operated by a switch operation, etc., and the parking brake operation can be electrically controlled, and smooth and easy automatic start control using the parking brake when starting on a slope. Enabling automatic on / off control of the parking brake. Some vehicles equipped with this type of EPB have a structure in which the parking brake is released by manual operation when a failure occurs in the electric system on the EPB side (for example, Patent Document 2).
Japanese Utility Model Publication No. 1-29063 JP 2000-309255 A

  By the way, in the brake system for a vehicle having the above-described regular hydraulic brake and EPB, the EPB has a remarkable phenomenon that the release of the EPB cannot be smoothly performed when the operation of the wire becomes dull or the control becomes inconvenient. Appears, and the driver can clearly recognize the change in the operability of the EPB at an early stage. That is, it is possible to respond quickly by recognizing the change in operation. On the other hand, in the case of regular hydraulic brakes, when the operating hydraulic pressure drops due to a booster failure or hydraulic piping failure, the brake pedal depression load changes slightly or the depression amount slightly decreases at the initial stage. Only a phenomenon such as an increase appears, and the braking force itself of the service hydraulic brake can be sufficiently secured so that the vehicle can be stopped safely. In addition, various measures are taken based on the concept of fail-safe.

  However, as described above, the change in the stepping load and the stroke is very small, and it is often difficult for the driver to recognize the change. In particular, there is a problem that it is difficult to recognize the change in operability of the service hydraulic brake operated in the running state.

  Accordingly, the present invention provides a brake system with an easy configuration that allows a driver to quickly and clearly recognize changes in the operability of a service hydraulic brake in a vehicle equipped with a service hydraulic brake and an electric parking brake. It aims at that.

  The present invention relates to a service hydraulic brake that operates by operating a brake pedal, and a brake system for a vehicle equipped with an electric parking brake, and a lock piece fixed to a drive wire for braking and releasing the electric parking brake; A lock member that is engageable with a lock piece and that is capable of advancing and retracting to maintain a braking state of the electric parking brake. The lock member is connected to a part of hydraulic piping of the service hydraulic brake, The lock member is retracted from the lock piece by a pressure equal to or higher than a predetermined value provided from a hydraulic pipe of the service hydraulic brake, and shifts to a brake release state of the electric parking brake.

  Here, the operating pressure equal to or higher than a predetermined value is a pressure that can sufficiently generate a braking force by the service hydraulic brake and function normally, and is preferably determined based on a design value of the service hydraulic brake.

  According to this configuration, a part of the hydraulic piping for operating the service hydraulic brake is used for releasing the braking of the electric parking brake. That is, the operation of the service hydraulic brake and the release operation of the electric parking brake can be associated with each other. For example, when a decrease in the pressure supplied to the service hydraulic brake occurs, it appears as a clear phenomenon that it is difficult to release the electric parking brake even if the pressure decrease is very small. By recognizing this clear phenomenon, it becomes possible to make the driver recognize the change in the operability of the service hydraulic brake quickly and clearly before the start of traveling.

  In the above configuration, the pressure provided from the hydraulic piping of the service hydraulic brake is generated based on an operation force that is greater than the normal operation of the brake pedal.

  For example, when the pressure supplied to the service hydraulic brake decreases, it is possible to compensate for the pressure decrease by increasing the depression force of the brake pedal or lengthening the depression stroke, and to generate a pressure above a predetermined value. . Drivers easily and sensitively to the fact that it was difficult to release the electric parking brake and the fact that the brake pedal depressing force increased or the depressing stroke became longer in order to release the electric parking brake. I can feel it. As a result, it is possible for the driver to recognize a change in the operability of the brake system, in particular, the regular hydraulic brake, clearly and reliably before starting the travel with an easy configuration.

  Further, in the above configuration, the lock member is engaged with an engagement pin that is operated by a release operation of the electric parking brake, and the lock member is provided from the hydraulic piping of the normal hydraulic brake. After the brake release preparation state is reached by a pressure equal to or greater than a predetermined value, the lock member is retracted and allowed to shift to the brake release state.

  According to this configuration, the engagement pin is retracted from the lock member only after the lock member is supplied with a pressure greater than or equal to a predetermined value. Therefore, the operation of releasing the electric parking brake and providing the pressure greater than the predetermined value from the normal hydraulic brake side are provided. Since the transition to the brake release state of the lock member is performed through two types of operations, for example, operations exceeding the normal operation of the brake pedal, attention is paid to the change in the operation in consideration of the difficulty in releasing the electric parking brake. As a result, it is possible for the driver to clearly and reliably recognize the change in the operability of the brake system with a simple configuration before the start of traveling.

  In the above configuration, the service hydraulic brake is an electronic control brake that controls a braking force by a pressure stored in the accumulator, and the pressure provided to the lock member is a control valve that controls a pressure supply amount from the accumulator. It is derived from the downstream side.

  According to this configuration, when there is no change in the operability of the service hydraulic brake, the electric parking brake is released smoothly. On the other hand, when there is a change in operability in the normal hydraulic brake, for example, a decrease in generated pressure due to normal operation, it becomes difficult to release the electric parking brake. For example, a strong depression of the brake pedal or a long stroke is required. Due to such a phenomenon that it is difficult to release the electric parking brake and a pressure supply operation exceeding a predetermined value, the driver can clearly and quickly recognize that the operability of the service hydraulic brake has changed. it can.

  In the above configuration, the service hydraulic brake is an electronic control brake that controls a braking force by a pressure stored in the accumulator, and the pressure provided to the lock member is a control valve that controls a pressure supply amount from the accumulator. It is derived from the upstream side.

  According to this configuration, when a failure of the accumulator system occurs, the lock member cannot be retracted from the lock piece. In other words, the release of the electric parking brake is prohibited, and the complete securing of the vehicle can be ensured.

  In the above configuration, the engagement pin and the lock member are engaged with each other by a tapered surface, and when the engagement pin cannot be operated, the lock member has a pressure based on an operation force higher than the normal operation of the brake pedal. By providing, the engagement pin is forcibly retracted, and the electric parking brake is shifted to a brake release state.

  According to this configuration, when a problem occurs in the control on the electric parking brake side, the lock member is slid on the tapered surface with respect to the engagement pin by providing a pressure higher than a predetermined value, so that the electric parking brake is Forced release is possible. At this time, the pressure for forcibly retracting the engagement pin is larger than when the electric parking brake control is functioning normally, so that a change in operability occurs on the regular hydraulic brake side. It is possible to easily recognize the distinction between the case and an abnormality occurring on the electric parking brake side. In this case, the normal hydraulic brake can generate a pressure that can forcibly retract the engagement pin.For example, it is possible to ensure a sufficient braking force only by increasing the amount of depression of the brake pedal or the pressure derived from the accumulator. Needless to say.

  According to the present invention, a part of the hydraulic piping for operating the service hydraulic brake is connected to the release mechanism of the electric parking brake, and is used for releasing the braking of the electric parking brake. The release action is related. As a result, when there is a change in the operability of the service hydraulic brake, it is possible to present to the driver as a clear change that the parking brake has become difficult to release when the vehicle is stopped. The change in the operability of the brake can be recognized quickly and clearly by the driver.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram illustrating a schematic configuration of a brake system 10 according to the present embodiment. The brake system 10 of the present embodiment includes a service hydraulic brake (service brake) 12 that performs deceleration, stop when the vehicle is running, and maintenance of a stopped state when the vehicle is stopped, and an electric parking brake (EPB) that maintains the stopped state of the vehicle. ) 14.

  The service hydraulic brake 12 has a known configuration using, for example, a vacuum booster, and a hydraulic pressure is generated by a master cylinder 18 that is operated by a driver depressing the brake pedal 16, and the hydraulic pressure is applied to the brake pipe 20. Is transmitted to the cylinder of the brake device 22 of each wheel (only one wheel is shown), and the brake shoe or brake pad is pressed against the brake drum or brake disc to generate a braking force. In the case of the present embodiment shown in FIG. 1, an anti-lock brake system (ABS) 24 is interposed in the route of the brake pipe 20, and each brake device 22 is optimal based on the running state of the vehicle, the road surface condition, and the like. The braking force, the braking timing, and the like can be controlled so as to realize the braking state.

  On the other hand, the EPB 14 has a drive wire 30 that is wound or unwound by a winding device 28 that rotates by driving of a driving device (for example, a motor) 26. A lock piece 32 that is engaged with a lock member of a lock mechanism described later is fixed to the distal end of the drive wire 30. Furthermore, drive wires 30a and 30b are fixed to the lock piece 32, and the tips thereof are connected to brake devices 34a and 34b incorporated in the rear wheel, for example. Therefore, by driving the motor 26 and winding up the drive wire 30 and further the drive wires 30a and 30b, the brake devices 34a and 34b can be operated, and the brake devices 34a and 34b can be shifted to the braking state. The motor 26 is subjected to a predetermined amount of forward rotation control or reverse rotation control by the EPB-ECU 36 in accordance with the pressed state of the EPB switch 38.

  In the case of FIG. 1, the brake device 22 of the service hydraulic brake 12 and the brake devices 34 a and 34 b of the EPB 14 are shown as separate configurations as the configuration of the brake device that operates with the service hydraulic brake 12 and the EPB 14. For example, the brake device 22 of the service hydraulic brake 12 is a disc brake type that clamps a disc that rotates with the wheel, and the brake device 34a, 34b of the EPB 14 is a drum brake that presses a pad against a drum formed on the inner peripheral side of the disc. Can be a type. The same applies when the disc brake type and the drum brake type are reversed. Further, the service brake 12 and EPB 14 may share the same brake device. In other words, the cylinder of the brake device 22 that is hydraulically driven by the service hydraulic brake 12 may be operated by the drive wires 30a and 30b. In this case, either the disc brake type or the drum brake type can be selected.

  In the EPB 14 described above, in order to maintain the state of the drive wire 30 wound up by driving the motor 26, that is, to maintain the state of the brake devices 34 a and 34 b after the motor 26 stops in the wound state of the drive wire 30. In addition, the lock piece 32 and the lock member 40 of the lock mechanism are engaged with each other. In the case of FIG. 1, the lock piece 32 has a sawtooth 32 a that faces downward in the figure, and the tip of the lock member 40 has a slope 40 a that meshes with the sawtooth 32 a. Details of the locking member 40 and its periphery are shown in FIG. As shown in FIGS. 1 and 2, the lock member 40 is configured as a piston of the cylinder 42, and the working oil enters and exits the pressure chamber 42 a from the brake pipe 20 through the pipe 44. The lock member 40 is always urged in the direction of the lock piece 32 (in the direction of arrow A in the figure) by an urging means (for example, a spring member) 46, and the inclined surface 40a of the lock member 40 is engaged with the saw tooth 32a. It is like that. Therefore, the lock member 40 moves in the direction away from the lock piece 32 (in the direction of arrow B in the figure) when the pressure supply greater than the urging force of the spring member 46 is received from the brake pipe 20 side, that is, the master cylinder 18. It becomes possible.

  1 and FIG. 2, the lock member 40 has a notch 40b at an intermediate position, and the notch 40b can be moved forward and backward by the operation of the solenoid 48 based on the operation of the EPB switch 38. The mating pin 50 is engaged. The engaging pin 50 is always urged in the direction of the notch 40b (in the direction of arrow C in the figure) by an urging member (for example, a spring member) 52. Further, as shown in FIG. 2, the tip 50a and the notch 40b of the engaging pin 50 have a tapered surface shape, and the locking member 40 urged in the direction A in FIG. 2 and C in FIG. In the region P, the engaging pins 50 biased in the direction are frictionally engaged with each other. That is, the lock member 40 cannot move due to the presence of the engagement pin 50 only by operating the normal brake pedal 16. Further, the engaging pin 50 that frictionally engages only by the operation of the EPB switch 38 cannot be retracted from the lock member 40, and the movement of the lock member 40 is prevented. That is, in this embodiment, in order to release the braking state of the EPB 14, an operation of pulling up the engagement pin 50 by operating the EPB switch 38 and a pressure equal to or higher than a predetermined value by operating the brake pedal 16 are performed. And the lock member 40 needs to be moved in the direction of arrow B in FIG. 2 to release the frictional engagement state.

  By configuring as described above, the brake system 10 is subject to fluctuations such as a decrease in operating hydraulic pressure due to a change in operability of the service hydraulic brake 12, such as a booster failure or a hydraulic piping failure on the service hydraulic brake 12 side. In this case, the release operation of the EPB 14 is affected. That is, when the hydraulic pressure generated by the operation of the brake pedal 16 is reduced, the retraction of the lock member 40 in the arrow B direction is restricted, and the release of the EPB 14 becomes difficult. As a result, the driver can recognize a change in operability of the service hydraulic brake 12. Of course, a pressure greater than a predetermined value can be generated by a strong operation of the brake pedal 16, the service hydraulic brake 12 can function normally, and the lock member 40 can be retracted to release the EPB 14. Can do.

  A procedure for causing the driver to recognize the operability of the service hydraulic brake 12 quickly and easily using the above-described brake system will be described with reference to the flowchart of FIG.

  When releasing the EPB 14, the driver first operates the EPB switch 38 (for example, pressing operation) (Y in S100). When the operation of the EPB switch 38 is performed, the solenoid 48 shifts to an operating state (S101) and tries to retract the engagement pin 50 from the lock member 40. As described above, at this time point, the friction force acts between the engagement pin 50 and the lock member 40, and therefore the engagement pin 50 does not move. Subsequently, the driver depresses the brake pedal 16, releases the frictional engagement between the engagement pin 50 and the lock member 40, retracts the engagement pin 50 from the lock member 40, and lock piece 32 of the lock member 40 itself. Evacuate from.

  At this time, if there is no failure of the hydraulic system (booster, hydraulic piping, etc.) of the service hydraulic brake 12 and it is functioning normally, the brake pedal 16 is operated with the normal brake depression force and normal depression stroke. Thus, the pressure (hydraulic pressure) reaches a predetermined value or more (Y in S102), and the lock member 40 is retracted from the lock piece 32. Thereafter, the winding device 28 is operated by the motor 26, and the brake devices 34a and 34b are released, that is, the EPB 14 is released via the drive wire 30, the lock piece 32, and the drive wires 30a and 30b (S103). That is, the EPB 14 can be released smoothly by operating the normal brake pedal 16. Note that, when the engagement between the lock member 40 and the lock piece 32 is released, the EPB 14 may be automatically released using an urging means or the like.

  On the other hand, when a failure occurs in the hydraulic system of the service hydraulic brake 12, the normal brake depression force and the normal depression stroke cannot sufficiently secure the pressure supplied to the pressure chamber 42a via the pipe 44. The pressure due to the operation of the brake pedal 16 in (S102) does not reach a predetermined value. That is, the retracting operation of the lock member 40 is not performed, and the releasing operation of the EPB 14 is prevented.

  Here, in order to release the EPB 14, the driver needs to generate a larger hydraulic pressure by the master cylinder 18 and must depress the brake pedal 16 with a stronger and longer stroke than usual. . That is, the driver can recognize that the release of the EPB 14 has become more difficult than usual, and can easily recognize that a failure has occurred in the service hydraulic brake 12 before the vehicle travels.

  Of course, since the master cylinder 18 can generate a pressure higher than a predetermined value by depressing the brake pedal 16 stronger than usual and with a long stroke, the normal hydraulic brake 12 normally operates with a braking force although there is a slight sense of incongruity. And the vehicle can be safely stopped. Then, the driver can quickly perform vehicle maintenance and the like.

  In the case of the present embodiment, the situation where it becomes difficult to release the EPB 14 may be caused by a failure on the side of the regular hydraulic brake 12 as described above, or by a failure of the EPB-ECU 36. When the EPB-ECU 36 breaks down, the engagement pin 50 does not retract from the lock member 40, so the lock member 40 does not move even if the same pressure as when the engagement pin 50 retracts normally is supplied to the pressure chamber 42a. . Therefore, the driver depresses the brake pedal 16 with a longer and longer stroke. As described above, the engaging pin 50 is urged by the spring member 52 to the notch 40b of the lock member 40 and is in contact with each other via the tapered surface, so that the moving force that overcomes the urging force of the spring member 52 is exerted. If pressure is supplied to the pressure chamber 42a so as to be generated, the EPB 14 can be released by retracting the lock member 40 from the lock piece 32 while retracting the engagement pin 50 in the direction of arrow D in FIG. In this case, since the driver needs to step on the brake pedal 16 with a longer stroke than that when the service hydraulic brake 12 fails, it is possible to recognize the failure of the EPB 14. In this case, since the pressure by the operation of the brake pedal 16 can be ensured to the extent that the EPB 14 can be forcibly released, the braking force on the service hydraulic brake 12 side can be sufficiently ensured. In this case, it is desirable that the driver perform maintenance of the EPB 14 as soon as possible.

  In the configuration of the brake system 10 shown in FIG. 1, the service hydraulic brake 12 is a service hydraulic brake that obtains braking force by directly guiding the hydraulic pressure generated by the master cylinder 18 to the brake device 22, but as shown in FIG. 4, Even if an electronically controlled brake (ECB) 56 in which the hydraulic pressure supplied to the brake device 22 of each wheel is electrically controlled by the ECU 54 is used as a regular hydraulic brake, the brake system 10 similar to the above can be configured.

  The ECB 56 mainly includes a master cylinder 18 that is operated by the brake pedal 16, an actuator 62 to which a motor 58 and an accumulator 60 are connected, and a brake device 22. In the ECB 56, the pipe 64 extends from the master cylinder 18 to the front brake device 22, for example, and the hydraulic pressure from the master cylinder 18 is connected when the ECB 56 is not controlling. Therefore, if the ECU 54 malfunctions, the hydraulic pressure generated in the master cylinder 18 by the operation of the brake pedal 16 is directly introduced into the front brake device 22 so that a good braking force can be obtained. ing.

  On the other hand, when the ECB 56 is operating normally, that is, in a state where electronic brake control can be performed, when the brake pedal 16 is depressed by the driver, the cut valve 66 disposed in the pipe 64 is closed, The depression amount of the brake pedal 16 is provided to the ECU 54 via a sensor (not shown). The ECU 54 controls the opening / closing amount of the pressure increasing valve (control valve) 68 in accordance with the provided depression amount of the brake pedal 16, and introduces a predetermined hydraulic pressure from the accumulator 60 to each brake device 22. The accumulator 60 can always output a desired pressure by driving a motor 58.

  When the ECB 56 configured in this way is used as a service hydraulic brake of the brake system 10 shown in FIG. 1, the pipe 44 in FIG. 1 is increased on, for example, a pipe 70 extending from the accumulator 60 to the brake device 22 on the front side. It can be connected to the downstream side of the pressure valve 68.

  In this case, when the ECB 56 operates normally and the operability of the service hydraulic brake 12 does not change (when it functions normally), as described with reference to FIGS. The lock member 40 can be retracted from the lock piece 32 by the depression amount and depression stroke, and the EPB 14 can be released by operating the normal brake pedal 16.

  On the other hand, when a failure occurs in the ECB 56 and a predetermined pressure cannot be supplied to the brake device 22, the pressure derived from the downstream side of the pressure increasing valve 68 also decreases, so that the normal depression amount and depression stroke of the brake pedal 16 are locked. The member 40 cannot be retracted from the lock piece 32. That is, the EPB 14 cannot be released. Therefore, in order to introduce a larger pressure into the pressure chamber 42a via the pipe 44, the driver needs to step on the brake pedal 16 with a longer stroke than the usual. As a result, the driver recognizes that the release of the EPB 14 is more difficult than usual, and recognizes the change in the operability of the service hydraulic brake before starting the vehicle.

  If a problem occurs in the EPB-ECU 36 or the like, the engaging pin 50 can be forcibly retracted by pushing the brake pedal 16 with a stronger and longer stroke in the same manner as described above, and the EPB 14 is released satisfactorily. be able to. Also in the above-described case, since the ECB 56 can generate a pressure that can release the EPB 14 by depressing the brake pedal 16 with a strong and long stroke, it goes without saying that the vehicle can secure a good braking force. .

  Further, when the ECB 56 is used as a regular hydraulic brake, it can be connected to the upstream side of the pressure increasing valve 68 on the pipe 70 extending from the accumulator 60 to the front brake device 22 as another connection form of the pipe 44. .

  In this case, the pressure from the accumulator 60 is controlled by the ECU 54 of the ECB 56 using, for example, the adjustment valve 72 and guided to the pipe 44. In this case, when the accumulator 60 or the like is functioning normally, the optimum pressure is introduced into the pipe 44, and the EPB 14 can be released as described above. On the other hand, when the accumulator 60 or the ECU 54 fails, that is, when the optimum pressure cannot be supplied to the brake device 22, the optimum pressure for the piping 44, that is, sufficient to retract the lock member 40 from the lock piece 32. Since it is impossible to supply a sufficient pressure, the release of the EPB 14 is prohibited. Based on the fact that the EPB 14 cannot be released, the driving vehicle is prohibited from starting the vehicle, and at the same time, it is possible to quickly recognize the abnormality of the service hydraulic brake.

  Even if the accumulator 60 or the like is functioning normally, if the EPB-ECU 36 is malfunctioning, the release of the EPB 14 is suppressed as described above, but the regulating valve 72 is controlled and the pressure from the accumulator 60 is controlled. By increasing the pressure, the engagement pin 50 can be forcibly retracted and the EPB 14 can be released. In this case, for example, by monitoring the adjustment state of the adjustment valve 72, the driver can recognize the malfunction on the EPB 14 side.

  In this way, the operability of the service hydraulic brake is changed (the oil pressure is changed) by configuring so that the release of the EPB is performed by receiving a pressure higher than a predetermined value from a part of the hydraulic piping of the service hydraulic brake. In this case, a clear phenomenon that it becomes difficult to release the EPB appears, and the driver can recognize the change in the operability of the service hydraulic brake before starting the vehicle.

  Also, when the change in operability of the regular hydraulic brake is, for example, a booster failure or hydraulic piping failure, etc., which can be compensated by increasing the brake pedal depression force or depression stroke, etc., and ensuring sufficient braking force This makes it possible for the driver to recognize the change in the service hydraulic brake by the supplementary operation and allows the vehicle to run normally by allowing the EPB to be released. Further, in the case of a failure on the EPB side, forcible release is permitted by supplying a pressure higher than a predetermined value from a part of the hydraulic piping of the normal hydraulic brake, and normal vehicle travel is enabled. In these cases, it is desirable that the driver perform maintenance of the regular hydraulic brake and EPB as soon as possible.

  In the present embodiment, the configuration shown in each figure and the procedure shown in the flowchart are examples, and the EPB is released by receiving a pressure higher than a predetermined value from a part of the hydraulic piping of the normal hydraulic brake and operating the normal hydraulic brake. Any other configuration can be arbitrarily changed as long as it is a configuration that allows the driver to recognize the change in sex due to the phenomenon that it is difficult to cancel the EPB, and the same effect as in the present embodiment can be obtained.

It is explanatory drawing explaining schematic structure of the brake system which concerns on this embodiment. It is explanatory drawing explaining the structure of the locking member of the brake system which concerns on this embodiment, and its periphery. 5 is a flowchart illustrating a procedure for releasing an electric parking brake in the brake system according to the present embodiment. It is explanatory drawing explaining the structural concept of the electronically controlled brake applicable to the brake system which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Brake system, 12 Service hydraulic brake, 14 Electric parking brake, 16 Brake pedal, 18 Master cylinder, 20 Brake pipe, 22 Brake device, 24 Antilock brake (ABS), 26 Motor, 28 Hoisting device, 30 Drive wire, 30a , 30b Drive wire, 32 Lock piece, 32a Saw tooth, 34a, 34b Brake device, 36 EPB-ECU, 38 EPB switch, 40 Lock member, 40a Slope, 40b Notch, 42 Cylinder, 42a Pressure chamber, 44, 64, 70 Piping, 46, 52 Spring member, 48 Solenoid, 50 Engagement pin, 50a Tip, 58 Motor, 60 Accumulator, 62 Actuator, 66 Cut valve, 68 Booster valve, 72 Adjustment valve.

Claims (6)

In a brake system for vehicles equipped with a service hydraulic brake that operates by operating the brake pedal and an electric parking brake,
A locking piece fixed to a drive wire for braking and releasing the electric parking brake;
A lock member that is engageable with the lock piece and is capable of moving forward and backward to maintain a braking state of the electric parking brake;
Including
A part of the hydraulic piping of the service hydraulic brake is connected to the lock member, and the lock member is retracted from the lock piece by a pressure not less than a predetermined value provided from the hydraulic piping of the service hydraulic brake. Brake system characterized by shifting to a brake release state.   The brake system is characterized in that the pressure provided from the hydraulic piping of the service hydraulic brake is generated based on an operating force that is greater than the normal operation of the brake pedal.   The lock member is engaged with an engagement pin that is operated by a release operation of the electric parking brake. The engagement pin is caused by a pressure that is greater than or equal to a predetermined value provided by the lock member from the hydraulic piping of the service hydraulic brake. 3. The brake system according to claim 1, wherein after the brake release preparation state is established, the brake system is retracted from the lock member and allows the lock member to shift to the brake release state. The regular hydraulic brake is an electronically controlled brake that controls the braking force by the pressure stored in the accumulator,
4. The brake according to claim 1, wherein the pressure provided to the lock member is derived from a downstream side of a control valve that controls a pressure supply amount from an accumulator. 5. system. The regular hydraulic brake is an electronically controlled brake that controls the braking force by the pressure stored in the accumulator,
The brake according to any one of claims 1 to 3, wherein the pressure provided to the lock member is derived from an upstream side of a control valve that controls a pressure supply amount from an accumulator. system. The engagement pin and the lock member are engaged with each other by a tapered surface, and when the engagement pin cannot be operated, the lock member provides the engagement pin by providing pressure based on an operation force higher than the normal operation of the brake pedal. The brake system according to any one of claims 3 to 5, wherein the brake system is forcibly retracted and shifts to a brake release state of the electric parking brake.

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