JP2011063266A - Vehicular brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a brake pedal stroke amount when a brake pedal is operated under the condition that a boosting function of a fluid pressure booster is failed and seal failure is occurred on a normally closed solenoid opening/closing valve of a circulating hydraulic modulator so as not to increase more than a brake pedal stroke amount under normal conditions. <P>SOLUTION: The output of a pressure sensor 17 detecting the pressure in a constant pressure chamber of a negative pressure type booster 14 and the output of a brake switch 18 switched from an off state to an on state according to the operation of a brake pedal 13 are input in an electronic control device 19. The electronic control device detects a booster function failure on the basis of the output of the pressure sensor, and drives an electric motor 16m of a circulating hydraulic modulator 16 when the brake pedal is operated in the booster function failure state, thereby driving circulating pumps 16k, 16l. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle brake device.

  As a vehicle brake device, a wheel cylinder that applies a braking torque to a wheel according to an input hydraulic pressure, a master cylinder that outputs a hydraulic pressure according to an input operation force to the wheel cylinder, and a brake pedal The hydraulic booster that boosts the operating force applied to the cylinder and inputs it to the master cylinder, and the master cylinder and the wheel cylinder to adjust the hydraulic pressure of the wheel cylinder to a hydraulic pressure different from the hydraulic pressure that the master cylinder outputs. 2. Description of the Related Art A vehicle brake device including a reflux type hydraulic pressure modulator interposed in a connected hydraulic pressure path is in widespread use.

  The reflux-type hydraulic pressure modulator is a component of an anti-lock control device or the like, and includes an auxiliary reservoir, a normally open electromagnetic on-off valve for blocking communication between the master cylinder and the wheel cylinder, and a wheel cylinder. A normally-closed electromagnetic on-off valve for communicating with the auxiliary reservoir, a recirculation pump for recirculating brake fluid accumulated in the auxiliary reservoir to a hydraulic path between the normally-open electromagnetic on-off valve and the master cylinder, and the recirculation pump And an electric motor for driving the motor.

  A seal failure of the normally closed electromagnetic on / off valve may occur due to a foreign matter caught between the valve body and the valve seat of the normally closed electromagnetic on / off valve of the reflux type hydraulic pressure modulator. When the brake pedal is operated in a state where the normally closed electromagnetic on-off valve seal is defective, the brake fluid sent from the master cylinder to the wheel cylinder leaks to the auxiliary reservoir, so that a desired wheel braking torque is obtained. Therefore, the brake pedal stroke amount required for this is significantly larger than the brake pedal stroke amount at the normal time when the seal failure is not generated in the normally closed electromagnetic on-off valve. In addition, when the boost function of the fluid pressure booster fails, the brake pedal operation force required to obtain the desired wheel braking torque is greater than the brake pedal operation force when the boost function of the fluid pressure booster is normal. Increase significantly. Therefore, when a driver who does not know that has a seal failure in the normally closed solenoid valve and the boost function of the fluid pressure booster has failed, There is a possibility that the stroke amount becomes insufficient and the desired wheel braking torque cannot be obtained.

  In the invention of this application, when the brake pedal is operated in a state where the boosting function of the fluid pressure booster has failed and the normally closed electromagnetic on-off valve of the reflux hydraulic pressure modulator is defective. An object of the present invention is to suppress an increase in the brake pedal stroke amount of the brake pedal stroke amount from the normal time.

  The invention according to claim 1 of the present application includes a wheel cylinder that applies a braking torque to a wheel according to an input hydraulic pressure, and a master cylinder that outputs a hydraulic pressure according to an input operation force to the wheel cylinder. In order to adjust the hydraulic pressure of the wheel cylinder to a hydraulic pressure different from the hydraulic pressure output from the master cylinder, and the hydraulic booster that boosts the operating force applied to the brake pedal and inputs the same to the master cylinder In the vehicle brake device including a reflux type hydraulic pressure modulator interposed in a hydraulic pressure path connecting the master cylinder and the wheel cylinder, the return type hydraulic pressure modulator includes an auxiliary reservoir, the master cylinder, A normally open electromagnetic on-off valve for blocking communication with the wheel cylinder, and the wheel cylinder as the auxiliary reserve A normally closed electromagnetic on-off valve for communicating with the auxiliary reservoir, a recirculation pump for recirculating brake fluid accumulated in the auxiliary reservoir to a hydraulic pressure path between the normally open electromagnetic on-off valve and the master cylinder, and the recirculation An electric motor for driving the pump, a booster function failure detecting means for detecting a function failure of the fluid pressure type booster, a brake pedal operation detecting means for detecting an operation of the brake pedal, An electric motor that drives the reflux pump of the reflux hydraulic pressure modulator in response to the booster function failure detecting means detecting the booster function failure and the brake operation detecting means detecting the brake pedal operation And an electric motor control means for driving the vehicle.

  In such a configuration, when the boosting function of the fluid pressure booster is lost, the electric motor of the reflux hydraulic pressure modulator is driven and the reflux pump is driven while the brake pedal is operated. Therefore, if the normally closed electromagnetic on-off valve of the reflux-type hydraulic pressure modulator has a sealing failure and the brake fluid sent from the master cylinder to the wheel cylinder leaks into the auxiliary reservoir, it leaks into the auxiliary reservoir. Since the brake fluid is recirculated to the hydraulic pressure path between the normally open electromagnetic on-off valve of the recirculation type hydraulic pressure modulator and the master cylinder by the recirculation pump, an increase in the brake pedal stroke amount is suppressed and a desired braking force is produced. be able to.

  The vehicle brake device includes a pump load state detection unit that detects a load state of the reflux pump, and the electric motor control unit is configured such that the pump load state detection unit starts driving the electric motor. The electric motor may be stopped in response to detecting a pump no-load state. In this way, driving of the electric motor and the reflux pump when there is no seal failure in the normally closed electromagnetic on-off valve, that is, useless driving of the electric motor and the reflux pump is suppressed. That is, when the seal failure is not generated in the normally closed electromagnetic on-off valve and the brake fluid does not leak into the auxiliary reservoir, it is not necessary to drive the electric motor and the reflux pump. When the electric motor of the reflux hydraulic pressure modulator is driven and the reflux pump is driven in response to the failure of the boost function of the fluid pressure booster and the brake pedal operation, a seal failure has occurred in the normally closed electromagnetic on-off valve. Otherwise, the reflux pump is in an unloaded state because no brake fluid has leaked into the auxiliary reservoir, and the electric motor is stopped when the pump load detection state detecting means detects the unloaded state of the reflux pump.

  Further, the electric motor control means may not resume the driving of the electric motor after stopping the electric motor in response to the pump load state detecting means detecting a pump no-load state. In such a configuration, when there is no seal failure in the normally closed electromagnetic on-off valve, unnecessary driving of the electric motor and the reflux pump is suppressed to one time.

It is a figure showing the whole brake device composition concerning the embodiment of the invention of this application. It is a flowchart explaining the effect | action of an electronic control apparatus. It is a flowchart explaining the effect | action of an electronic control apparatus. It is a flowchart explaining the effect | action of an electronic control apparatus.

  Hereinafter, an embodiment of the invention of this application will be described with reference to the drawings. FIG. 1 shows an overall configuration of a vehicle brake device 10. FIG. 2 is a flowchart showing the operation of the electronic control unit 19 in FIG. As shown in FIG. 1, the vehicle brake device 10 includes a wheel cylinder 11 </ b> A that applies a braking torque corresponding to the input hydraulic pressure to the front left wheel, and a braking torque that corresponds to the input hydraulic pressure. A wheel cylinder 11B to be applied to the wheel, a wheel cylinder 11C to apply a braking torque according to the input hydraulic pressure to the rear left wheel, and a wheel cylinder to apply a braking torque according to the input hydraulic pressure to the rear right wheel 11D, a master cylinder 12 that outputs hydraulic pressure corresponding to the input operation force to the wheel cylinders 11A to 11D, and a negative that inputs the operation force applied to the brake pedal 13 to the master cylinder 12 The reflux type hydraulic pressure module 15A, 15B that connects the pressure type booster 14, the master cylinder 12 and the wheel cylinders 11A to 11D. And Regulator 16, and an electronic control unit 19 that drives the electric motor 16m which is a component of the reflux type hydraulic modulator 16.

  In the master cylinder 12, a front piston and a rear piston are accommodated in a cylinder to form a front pressure chamber and a rear pressure chamber. These pistons are advanced by an input from the negative pressure booster 14, so that both pressure chambers are formed. The front pressure chamber is connected to the hydraulic pressure passage 15A, and the rear pressure chamber is connected to the hydraulic pressure passage 15B.

  The negative pressure type booster 14 is divided into a constant pressure chamber on the front side of the power piston and a variable pressure chamber on the rear side of the power piston by a power piston in the housing, and negative pressure is supplied to the constant pressure chamber from a negative pressure source 20 such as an intake manifold of the engine. The power piston is always input, and there are three positions in the power piston according to the relative displacement between the input rod 14a connected to the brake pedal 13 and the power piston (an output decreasing position that cuts off the variable pressure chamber from the atmosphere and communicates with the constant pressure chamber, A valve mechanism that switches between the output holding position that shuts off the chamber from both the atmosphere and the constant pressure chamber, and the output increasing position that shuts off the variable pressure chamber from the constant pressure chamber and communicates with the atmosphere). The forward force generated in the power piston due to the differential pressure between the two and the forward force applied to the input rod (the magnitude according to the operating force applied to the brake pedal) While output by the output rod to the master cylinder 14, is well known that reaction force corresponding to the output is configured to join to the input rod 14a.

  As is well known, the reflux-type hydraulic pressure modulator 16 is for adjusting the hydraulic pressure of the wheel cylinders 11A to 11D to a value different from the hydraulic pressure output from the master cylinder 12, and is a component such as an anti-lock control device. It is supposed to be.

  The recirculation type hydraulic pressure modulator 16 communicates the auxiliary reservoirs 16a and 16b, the normally open electromagnetic opening / closing valve 16c for shutting off the wheel cylinder 11A from the front pressure chamber of the master cylinder 12, and the wheel cylinder 11A to the auxiliary reservoir 16a. A normally closed electromagnetic on-off valve 16d for normally closing, a normally open electromagnetic on-off valve 16e for isolating the wheel cylinder 11B from the front pressure chamber of the master cylinder 12, and a normally closed for communicating the wheel cylinder 11B to the auxiliary reservoir 16a Type electromagnetic on / off valve 16f, normally open type electromagnetic on / off valve 16g for isolating the wheel cylinder 11C from the rear pressure chamber of the master cylinder 12, and normally closed type electromagnetic on / off valve for communicating the wheel cylinder 11C to the auxiliary reservoir 16b 16h, the wheel cylinder 11D is located behind the master cylinder 12. A normally open type electromagnetic on / off valve 16i for shutting off from the power chamber, a normally closed type electromagnetic on / off valve 16j for communicating the wheel cylinder 11D to the auxiliary reservoir 16b, and a brake fluid in the auxiliary reservoir 16a for normally opening type electromagnetic open / close A recirculation pump 16k for recirculating to a hydraulic pressure passage 15A between the valves 16c and 16e and the master cylinder 12 and a brake fluid in the auxiliary reservoir 16b between the normally open electromagnetic on-off valves 16g and 16i and the master cylinder 12 The main component is a reflux pump 16l for refluxing to the hydraulic pressure path 15B and an electric motor 16m for driving the reflux pumps 16k and 16l.

  The electromagnetic on-off valves 16c and 16d are driven when adjusting the hydraulic pressure of the wheel cylinder 11A, the electromagnetic on-off valves 16e and 16f are driven when adjusting the hydraulic pressure of the wheel cylinder 11B, and the electromagnetic on-off valves 16g and 16h are wheels. It is driven when adjusting the hydraulic pressure of the cylinder 11C, and the electromagnetic on-off valves 16i and 16j are driven when adjusting the hydraulic pressure of the wheel cylinder 11D. For example, when reducing the hydraulic pressure in the wheel cylinder 11A, the electromagnetic on-off valve 16c is closed and the electromagnetic on-off valve 16d is opened. As a result, the brake fluid is discharged from the wheel cylinder 11A to the auxiliary reservoir 16a, and the hydraulic pressure in the wheel cylinder 11A is reduced. When the hydraulic pressure in the wheel cylinder 11A is reduced and then increased again, the electromagnetic on-off valve 16d is closed and the electromagnetic on-off valve 16c is opened. As a result, brake fluid is supplied from the master cylinder 12 side of the electromagnetic on-off valve 16c to the wheel cylinder 11A, and the hydraulic pressure in the wheel cylinder 11A increases. When the hydraulic pressures of the wheel cylinders 11A to 11D are adjusted by driving the electromagnetic on-off valves 16c to 16j, the electric motor 16m is driven to drive the reflux pumps 16k and 16l, and the brake fluid discharged to the auxiliary reservoirs 16a and 16b. Are successively recirculated to the hydraulic pressure paths 15A and 15B between the electromagnetic on-off valves 16c, 16e, 16g and 16i and the master cylinder 12. Thereby, the increase in the stroke amount of the brake pedal 13 is suppressed.

  When the brake pedal 13 is operated in a state where a seal failure has occurred in any one of the normally closed electromagnetic opening / closing valves 16d, 16f, 16h, 16j, for example, the normally closed electromagnetic opening / closing valve 16d, the wheel is moved from the master cylinder 12 to the wheel. Since the brake fluid sent to the cylinders 11A and 11B leaks to the auxiliary reservoir 16a, the amount of brake pedal stroke required to produce the desired braking force is not good enough for the normally closed electromagnetic on-off valve 16d. Not significantly increased than the normal brake pedal stroke amount. If the brake pedal 13 is operated under the condition that the normally closed electromagnetic on-off valve has a seal failure, if the boosting function of the negative pressure booster 14 is lost, the brake pedal 13 is sufficiently There is a possibility that a stroke cannot be made and a desired braking force cannot be produced.

  In order to cope with this problem, the output signal of the pressure sensor 17 for detecting the pressure P output from the negative pressure source 20 to the constant pressure chamber of the negative pressure booster 14 and the brake pedal 13 is depressed to turn off. An electronic control device 19 is installed to drive the electric motor 16m of the reflux hydraulic pressure modulator 16 based on the output signal of the brake switch 18 that is switched on.

  The electronic control unit 19 is configured by a microcomputer or the like, and executes a program corresponding to the flowchart of FIG. 2 at a predetermined cycle when the ignition switch of the vehicle is closed. In FIG. 2, first, initialization is performed in step S11, then, in step S12, the pressure P output from the negative pressure source 20 to the constant pressure chamber of the negative pressure booster 14 is detected, and then in step S13. The booster function failure of the negative pressure booster 14 is determined. In this boost function failure determination, the detected pressure P is compared with a predetermined threshold value Pr (the upper limit value of the constant pressure chamber pressure for the negative pressure booster 14 to perform the boost function), and the detected pressure P is If it is higher than the threshold value Pr, it is determined that the booster function has failed, and the process proceeds to step S14. If the detected pressure P is not higher than the threshold value Pr, the process returns to step S12.

  In step S14, it is determined whether the brake switch 18 is on. If the brake switch 18 is not on, that is, if the brake pedal 13 is not operated, step S14 is repeated. If the brake switch 18 is on, that is, if the brake pedal 13 is operated, the process proceeds to step S15. In step S16, the electric motor 16m of the reflux type hydraulic modulator 16 is driven.

  In step S16, it is determined whether or not the brake switch 18 is off. If the brake switch 18 is off, that is, if the operation of the brake pedal 13 is released, the electric motor 16m is stopped in step S17. After that, the process returns to step S12, but if the brake switch 18 is not OFF, the process returns to step S15.

  Thus, when the boosting function of the negative pressure type booster 14 is lost and the brake pedal 13 is depressed, the electric motor 16m is driven and the reflux pumps 16k and 16l are driven. The brake fluid sent from the master cylinder 12 to the wheel cylinders 11A to 11D to the auxiliary cylinders 16a and 16b due to a seal failure in any of the 16 normally closed electromagnetic on-off valves 16d, 16f, 16h and 16j. Even if it leaks, the brake fluid leaked into the auxiliary reservoirs 16a and 16b is caused to flow between the normally open electromagnetic on / off valves 16c, 16e, 16g and 16i of the reflux hydraulic pressure modulator 16 and the master cylinder 12 by the reflux pumps 16k and 16l. Since the fluid is recirculated to the hydraulic pressure paths 15A and 15B, an increase in the brake pedal stroke amount is suppressed. It is possible to produce the desired braking force.

  The pressure sensor 17 and the electronic control device 19 constitute booster function failure detection means, the brake switch 18 constitutes brake operation detection means, and the electronic control device 19 constitutes electric motor control means. .

  The electronic control device 19 may perform the operation shown in the flowchart of FIG. In this case, the electronic control device 19 includes a current sensor that detects the current value I of the electric motor 16m. 3 is different from the flowchart of FIG. 2 in that step S118 is added between step S115 corresponding to step S15 of FIG. 2 and step S116 corresponding to step S16 of FIG. In step S118, it is determined whether or not the current value I of the electric motor 16m is equal to the no-load current value Ir. If the current value I is not equal to the no-load current value Ir, the process proceeds to step S116. If it is equal to the no-load current value Ir, the routine proceeds to step S117 corresponding to step S17 in FIG. 2, and the electric motor 16m is stopped. Since the current value I of the electric motor 16m corresponds to the load of the reflux pumps 16k and 16l, the detection of the current value I corresponds to the detection of the load of the reflux pumps 16k and 16l. If the current value I is equal to the no-load current value Ir, it means that the reflux pumps 16k, 16l are not loaded, which means that there is no brake fluid in the auxiliary reservoirs 16a, 16b, and thus a normally closed type. It means that none of the electromagnetic on-off valves 16d, 16f, 16h, and 16j has a sealing failure. Steps S111 to S114 correspond to steps S11 to S14 in FIG.

  The execution of the program corresponding to the flowchart of FIG. 3 starts driving the electric motor 16m in response to the detection of the boost function failure of the negative pressure booster 14 and the depression of the brake pedal 13. Since the electric motor 16m is stopped if there is no defective seal in any of the closed electromagnetic on-off valves 16d, 16f, 16h, 16j, useless driving of the electric motor 16m and the reflux pumps 16k, 16l is suppressed.

  The electronic control device 19 constitutes a pump load state detecting means.

  Further, the electronic control device 19 may perform the action shown in the flowchart of FIG. Also in this case, the electronic control device 19 includes a current sensor for detecting the current value I of the electric motor 16m. 4 differs from the flowchart of FIG. 3 in that the current value I of the electric motor 16m is determined to be equal to the no-load current value Ir in step S218 corresponding to step S118 of FIG. After stopping to stop the electric motor 16m, it is not returned to step S211 corresponding to step S111 in FIG. Thereby, useless driving of the electric motor 16m and the reflux pumps 16k and 16l is suppressed to one time. Steps S211 to S217 correspond to steps S111 to S117 in FIG. 3, respectively.

  In the vehicle brake device 10 of FIG. 1, the negative pressure booster 14 is used. However, it is also possible to use a hydraulic booster that performs a boost function using the power hydraulic pressure input from the power hydraulic pressure source. Good. In this case, the boost function failure of the hydraulic booster is detected by detecting the power hydraulic pressure output from the power hydraulic pressure source to the hydraulic booster by the pressure sensor, and the detected power hydraulic pressure is a predetermined threshold value. (The hydraulic booster is the lower limit value of the power hydraulic pressure for performing the boost function) and is detected, and when the detected power hydraulic pressure falls below a predetermined threshold It is determined that the booster function has failed.

  As described above, according to the invention of this application, the boosting function of the fluid pressure booster has failed, and the normally closed electromagnetic on-off valve of the reflux hydraulic pressure modulator has a poor seal. The brake pedal stroke amount when the brake pedal is operated can be suppressed from increasing more than the normal brake pedal stroke amount, and the situation where the desired wheel braking torque cannot be obtained can be suppressed. Can do.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle brake device, 11A-11D ... Wheel cylinder, 12 ... Master cylinder, 13 ... Brake pedal, 14 ... Negative pressure type booster, 16 ... Reflux type hydraulic pressure modulator, 16m ... Electric motor, 16k, 16l ... Reflux pump, 17 ... Pressure sensor, 18 ... Brake switch, 19 ... Electronic control unit.

Claims (2)

A wheel cylinder that applies a braking torque to the wheel according to the input hydraulic pressure, a master cylinder that outputs a hydraulic pressure according to the input operating force to the wheel cylinder, and an operating force applied to the brake pedal. Connects the master cylinder and the wheel cylinder in order to adjust the hydraulic pressure of the wheel cylinder to a hydraulic pressure different from the hydraulic pressure output by the master cylinder, and a hydraulic booster that boosts and inputs to the master cylinder An auxiliary reservoir, a normally open solenoid valve for blocking communication between the master cylinder and the wheel cylinder, and a normally closed valve for communicating the wheel cylinder to the auxiliary reservoir. Type electromagnetic on / off valve, and brake fluid accumulated in the auxiliary reservoir for the normally open type electromagnetic on / off valve and the master cylinder In the vehicle braking apparatus having a reflux pump for recirculating the liquid passage, and a reflux-type hydraulic modulator that is configured with an electric motor for driving the reflux pump between,
A booster function failure detecting means for detecting a function failure of the fluid pressure type booster;
Brake pedal operation detecting means for detecting operation of the brake pedal;
An electric motor that drives the reflux pump of the reflux hydraulic pressure modulator in response to the booster function failure detecting means detecting the booster function failure and the brake operation detecting means detecting the brake pedal operation And an electric motor control means for driving the vehicle. The vehicle brake device according to claim 1,
Pump load state detection means for detecting the load state of the reflux pump is provided, and the electric motor control means detects that the pump load state detection means has detected no pump load after starting to drive the electric motor. The electric motor is stopped according to the vehicle brake device.