JP4207888B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device capable of controlling the working fluid pressure to the brake cylinder of each wheel separately from a master cylinder that boosts the working fluid pressure by depressing a brake pedal.

Conventional brake control devices include the following. For example, a normal operation of a hydraulic pump that includes a master cylinder that inputs a depression force according to the depression amount of a brake pedal through a return spring and outputs a braking pressure according to the input, and that supplies the braking pressure to the wheel cylinder. At times, the master cylinder and the wheel cylinder are shut off and the hydraulic pump is operated to control the wheel cylinder hydraulic pressure to the target hydraulic pressure calculated based on the detected value of the pedal force sensor, while the hydraulic pump In the case of failure, it is known that the wheel cylinder pressure is directly controlled by the master cylinder pressure by communicating the master cylinder and the wheel cylinder (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-157439

However, in the conventional brake control device, the return spring operates even when the hydraulic pump fails. As a result, when the master cylinder pressure is supplied directly to the wheel cylinder, the pedal stroke (loss stroke) for generating the wheel cylinder pressure is increased by the amount that the return spring contracts when the brake pedal is depressed, and the braking force is increased. There is an unsolved problem of becoming weak.
Accordingly, an object of the present invention is to provide a brake control device that can obtain an appropriate braking force according to depression of a brake pedal even when an abnormality occurs.

In order to achieve the above object, the brake control device according to the present invention communicates the master cylinder and the wheel cylinder when it is determined that the predetermined condition is satisfied, and restricts the expansion and contraction of the return spring by the expansion and contraction restricting means. The braking force of the wheel cylinder is controlled by the working fluid pressure output from the master cylinder.
At this time, it has a piston connected to one end of the return spring, and a cylinder connected to the other end of the return spring and in which the piston is slidably disposed. When it is determined that there is, the sliding restriction means regulates the expansion and contraction of the return spring by regulating the sliding of the piston with respect to the cylinder. The sliding restricting means has a permanent magnet installed on the piston and an electromagnet installed on the piston rod side of the cylinder, and activates the electromagnet when it is determined that the predetermined condition is satisfied. To regulate the sliding of the piston.

According to the present invention, when it is determined that the predetermined condition is satisfied , the return spring is not operated by fixing the piston energized by the return spring by operating the electromagnet. When supplying pressure directly to the wheel cylinder, it is possible to eliminate the loss stroke due to the return spring contracting according to the depression of the brake pedal, and to obtain an appropriate braking force according to the depression of the brake pedal. Is obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration diagram of a brake control device according to the first embodiment. In the figure, reference numeral 1 denotes a brake pedal, and reference numeral 2 denotes a master cylinder whose pressure is increased according to the depression amount of the brake pedal 1. .
The master cylinder 2 has two output systems, and outputs the working fluid pressure to these two output systems. Hereinafter, one output system is referred to as a primary system, and the other is referred to as a secondary system. These working fluid pressures generate braking force on the wheels 5a and 5b via the master cylinder cut valves (standby opening) 3a and 3b and the normally open solenoid valves (standby opening) 4a and 4b. It is supplied to the wheel cylinders 6a and 6b.

Master cylinder pressure sensors 7a and 7b, which are pressure sensors for detecting the working fluid pressure, are interposed on the output sides of the master cylinder 2.
On the other hand, a pump 9 is connected to a reservoir 8 arranged in parallel with the master cylinder 2. The pump 9 is composed of an electric motor 9a and a hydraulic pump 9b that is rotationally driven by the electric motor 9a. The braking pressure output from the pump 9 is between the master cylinder cut valve 3a and the normally open electromagnetic valve 4a. Supplied to the fluid path. The fluid path between the master cylinder cut valve 3a and the normally open solenoid valve 4a and the fluid path between the master cylinder cut valve 3b and the normally open solenoid valve 4b are normally closed (closed during standby). Are connected via a system shutoff valve 10 which is an electromagnetic on-off valve.
Further, the wheel cylinders 6a and 6b and the reservoir 8 are connected via normally closed solenoid valves (closed during standby) 11a and 11b, and control the discharge of hydraulic pressure from the wheel cylinders 6a and 6b to the reservoir 8. It is configured as follows.

  A stroke simulator 12 is connected to the upstream side of the master cylinder cut valve 3b on one output side of the master cylinder 2 via a stroke simulator cut valve 13 which is a normally closed (standby closed) electromagnetic on-off valve. ing. When the brake control device (brake-by-wire system) is activated and normal, the master cylinder cut valves 3a and 3b are closed to disconnect the master cylinder 2 and the wheel cylinders 6a and 6b, and the stroke simulator cut valve 13 is energized. In this state, the output side and the stroke simulator 12 are connected. When the stroke simulator cut valve 13 is in the open state, the stroke simulator 12 is configured to absorb the working fluid pressure output from the master cylinder 2.

The stroke simulator 12 includes a cylinder, a piston 12a slidably disposed in the cylinder, and a coil spring 12b that urges the piston 12a, and a pedal corresponding to the stroke of the brake pedal 1. Generate reaction force.
The master cylinder 2 has pressure generating chambers 2a and 2b, and these pressure generating chambers 2a and 2b are formed by pistons 2c and 2d in the cylinder. A spring 2e is installed in the pressure generation chamber 2a, and a spring 2f is installed in the pressure generation chamber 2b.

That is, the hydraulic fluid pressure is output from each of the pressure generating chambers 2a and 2b, the output system from the pressure generating chamber 2a corresponds to the primary system, and the output system from the pressure generating chamber 2b is the secondary system. It corresponds to.
The stepping force applied to the brake pedal 1 by the driver is input to the piston 2c via the return spring 14. Here, the spring constant of the return spring 14 is set smaller than the spring constants of the springs 2e and 2f. Therefore, the return spring 14 generates a pedal reaction force in a low pedaling force region before the stroke simulator 12 operates.

  A piston 15b is connected to one end of the return spring 14, and a cylinder 15a in which the piston 15b is slidably disposed is connected to the other end. That is, the return spring 14 moves the piston 15b slidably disposed in accordance with the depression of the brake pedal 1 within the cylinder 15a interposed between the brake pedal 1 and the master cylinder 2 to the master cylinder 2 side. It is energized from. The return spring 14 is fully extended in a non-braking state in which the stepping force by the brake pedal 1 is zero, and the position of the piston 15b at this time is referred to as an initial position of the piston 15b.

  Further, a permanent magnet 16 is installed on the piston 15b, and an electromagnet 17 is installed on the piston rod 15d side in the cylinder 15a, that is, at a position where it comes into contact with the permanent magnet 16 when the return spring 14 is fully extended. . The electromagnet 17 is configured to operate when a predetermined condition described later is satisfied, and to restrict the sliding by forcibly returning the piston 15b to the initial position. In this way, by restricting the sliding of the piston 15b, the operation of the return spring 14 when the brake pedal 1 is depressed is restricted.

The brake control device further includes a stroke sensor 18 for detecting the amount of depression of the brake pedal 1 and wheel cylinder pressure sensors 19a and 19b for detecting the working fluid pressure of the wheel cylinder.
Here, the state where the predetermined condition is satisfied in the present embodiment refers to a state where an abnormality (failure) has occurred in any of the master cylinder pressure sensors 7a, 7b, the pump 9, and the stroke sensor 18.

  Each of the master cylinder cut valves 3a and 3b, the normally open solenoid valves 4a and 4b, the system shutoff valve 10, the normally closed solenoid valves 11a and 11b, and the stroke simulator cut valve 13 is a control unit 30 that is supplied to a solenoid. The open / closed state is controlled by the control signal from, and when the control signal is in the off state (non-energized state), it is in the normal state, and when in the on state (energized state), it is configured to switch to the offset position Yes.

  The control unit 30 is configured via an arithmetic processing device such as a microcomputer, for example. In the control unit 30, when the master cylinder 2 and the wheel cylinders 6a and 6b are in a normal state, the master cylinder cut valves 3a and 3b between the master cylinder 2 and the wheel cylinders 6a and 6b are closed to thereby connect the master cylinder 2 and the wheel cylinders 6a and 6b. The hydraulic pressure supplied to the wheel cylinders 6a and 6b by the pump 9 is generated. At this time, the stroke simulator cut valve 13 is opened, and the stroke simulator 12 absorbs the depression of the brake pedal 1.

When an abnormality occurs, the master cylinder cut valves 3a and 3b are opened to connect the master cylinder 2 and the wheel cylinders 6a and 6b, and the hydraulic pressure of the wheel cylinders 6a and 6b is directly generated by the hydraulic pressure of the master cylinder 2. Let At this time, by closing the system shut-off valve 10, the primary and secondary systems of the master cylinder generate hydraulic pressure independently.
When this abnormality occurs, the stroke simulator cut valve 13 is closed to prevent the brake fluid from flowing into the stroke simulator 12, thereby reducing the loss stroke caused by the stroke simulator 12.

Next, a brake fluid pressure control processing procedure executed by the control unit 30 will be described with reference to FIG.
This brake fluid pressure control process is executed as a timer interrupt process at a predetermined time (for example, 10 to 1000 msec) set in advance, and first, various data are read in step S1. Specifically, the detection values of the master cylinder pressure sensors 7a and 7b, the stroke sensor 18 and the wheel cylinder pressure sensors 19a and 19b are read.

  Next, the process proceeds to step S2 to determine whether or not the system is abnormal. This determination is made by determining whether the master cylinder pressure sensors 7a and 7b, the stroke sensor 18 and the pump 9 are abnormal. If any abnormality is detected, the process proceeds to step S3 and the failure control described later is performed. Timer interrupt processing ends. On the other hand, if no abnormality is detected, it is determined that the system is normal and the process proceeds to step S4.

In step S4, a control signal for controlling the master cylinder cut valves 3a and 3b to be closed is output, and a control signal for controlling the stroke simulator cut valve 13 to be opened is output, and the process proceeds to step S5.
In step S5, a brake fluid pressure command value is calculated from the master cylinder pressure sensor detection value and the stroke sensor detection value read in step S1, and the process proceeds to step S6.

In step S6, the pump 9 is operated to generate hydraulic pressure, and in step S7, the normally open solenoid valves 4a and 4b and the normally closed solenoid valves 11a and 11b are controlled to control the hydraulic pressure of the wheel cylinders 6a and 6b. Is controlled to be the brake fluid pressure command value calculated in step S5, and the timer interruption process is terminated.
Further, in the failure time control in step S3, the failure time control process shown in FIG. 3 is performed. First, in step S31, a control signal for closing the stroke simulator cut valve 13 is output, and then in step S32, A control signal for closing the system shutoff valve 10 is output to shut off the primary and secondary systems.

In step S33, a control signal for opening the normally open solenoid valves 4a and 4b is output, and then the process proceeds to step S34 to output a control signal for closing the normally closed solenoid valves 11a and 11b. Then, the process proceeds to step S35.
In step S35, a control signal for opening the master cylinder cut valves 3a and 3b is output to connect the master cylinder 2 and the wheel cylinders 6a and 6b, and the process proceeds to step S36.

In step S36, the electromagnet 17 is actuated, the piston 15b is forcibly returned to the initial position and fixed to the cylinder 15a to fix the return spring 14 to the fully extended state, and then the control at the time of failure is terminated. Return to the predetermined main program.
Step S36, the permanent magnet 16 and the electromagnet 17 in FIG. 3 correspond to the sliding restricting means, and the sliding restricting means constitutes an expansion / contraction restricting means.

Next, the operation of this embodiment will be described.
Now, it is assumed that the driver is not operating a brake and is in a non-braking state. In this case, since the brake pedal 1 is not depressed, the master cylinder 2 is in the state shown in FIG. At this time, the master cylinder cut valves 3a and 3b are closed, the system shutoff valve 10 and the stroke simulator cut valve 13 are opened, and the electromagnet 17 is inactive.

  From this state, when the driver depresses the brake pedal 1 and performs a braking operation, the electromagnet 17 is inactive, so the piston 15b is pushed and the return spring 14 is displaced as shown in FIG. B and displacement A on the primary side of the master cylinder occur. Since the master cylinder cut valve 3a is closed, the secondary side of the master cylinder is not displaced.

  That is, in the brake fluid pressure control process of FIG. 2, the brake fluid pressure command value is calculated based on the stroke sensor detected value and the master cylinder pressure sensor detected value in step S5, and then the pump 9 is operated in step S6 to operate the fluid. Pressure is generated and introduced into the wheel cylinders 6a and 6b. In step S7, the normally open solenoid valves 4a and 4b and the normally closed solenoid valves 11a and 11b are controlled to adjust the wheel cylinder pressure to the brake fluid pressure command value. In addition, the stroke simulator 12 generates a pedal reaction force corresponding to the stroke and absorbs and consumes the working fluid pressure output from the master cylinder 2 to ensure a feeling of depression of the brake pedal 1.

  On the other hand, if an abnormality occurs in the non-braking state shown in FIG. 4A, the process proceeds to step S3 based on the determination in step S2. In the failure time control process shown in FIG. 3, the electromagnet 17 is actuated to fix the piston 15b and the return spring 14 in the state shown in FIG. Therefore, when the driver depresses the brake pedal 1 to perform braking in this state, the return spring 14 is not displaced and pressure is applied to the piston of the master cylinder 2. Therefore, when the master cylinder pressure is directly supplied to the wheel cylinder, the loss stroke due to the return spring 14 is eliminated, and an appropriate braking force according to the depression of the brake pedal can be obtained.

  Further, when an abnormality occurs in the braking state shown in FIG. 4B, the piston 15b is returned to the initial position by operating the electromagnet 17 in the failure time control process. At this time, since the depression force is applied to the brake pedal 1, the piston 15b is not displaced as shown in FIG. 4C, and the external cylinder 15a and the rod 15c are displaced to apply pressure to the master cylinder 2. It will be. That is, the stroke amount C of the master cylinder 2 is the sum of the primary displacement A and the return spring displacement B. Note that, when an abnormality occurs, the master cylinder cut valve 3a is controlled to be in an open state, so that displacement also occurs on the secondary side of the master cylinder.

  By the way, when an abnormality occurs when the brake pedal is depressed, simply by fixing the return spring, no braking force is generated unless the brake pedal is further depressed. However, according to the present invention, the above configuration is advantageous in that the loss stroke of the return spring displacement due to depression of the brake pedal when an abnormality occurs is shortened. In addition, even when the pedal stroke is held when an abnormality occurs, the braking force corresponding to the pedal stroke can be generated immediately, so that appropriate brake control suitable for the driver's feeling can be performed. .

Thus, in the first embodiment, it communicates the master cylinder and the wheel cylinder when an abnormality occurs, when supplying the master cylinder pressure directly to the wheel cylinder, to fix the piston return spring biases Because of this configuration, the return spring can be deactivated in the event of an abnormality, and the pedal stroke (loss stroke) for the return spring operation before the wheel cylinder hydraulic pressure is generated can be shortened. An appropriate braking force can be obtained.

  In addition, a permanent magnet is installed on the piston biased by the return spring, and an electromagnet is installed on the brake pedal side of the cylinder, which is the initial position of the piston. When an abnormality occurs, the electromagnet is activated to force the piston to the initial position. Since it is returned to the fixed state, it is possible to eliminate the loss stroke corresponding to the return spring operation, and it is possible to immediately generate the braking force corresponding to the pedal stroke when an abnormality occurs.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the piston is fixed using a permanent magnet and an electromagnet when an abnormality occurs in the first embodiment described above, whereas an air introduction valve and a negative pressure introduction valve are used. The piston is fixed.
That is, as shown in FIG. 5, the structure of the return spring portion in the second embodiment is provided with an air introduction hole 101 in the return spring 14 side chamber among the chambers formed in the cylinder 15a by the piston 15b, and the piston rod A negative pressure introduction valve 102 and an air introduction valve 103 are provided in the 15d side chamber. When normal, the negative pressure introduction valve 102 is closed, the atmospheric introduction valve 103 is opened, and the piston 15b is slidable, and the return spring 14 is activated. On the other hand, when an abnormality occurs, the negative pressure introduction valve 102 is opened, the atmospheric introduction valve 103 is closed, the piston 15b is returned to the initial position and fixed, and the return spring 14 is deactivated. .

Here, the hose or the like that connects the negative pressure introduction valve 102 and the engine 104 is configured to move flexibly, such as a rubber hose, and the outer cylinder 15a is movable.
Further, each of the negative pressure introduction valve 102 and the atmospheric introduction valve 103 is configured such that the open / close state is controlled by a control signal from the control unit 30 supplied to the solenoid. This negative pressure introduction valve 102 corresponds to the pressure control means.

  FIG. 6 is a flowchart showing a processing procedure of the failure time control process executed in step S3 of FIG. 2 in the second embodiment. In the failure time control process of FIG. 3, the process of step S36 is performed. The process is the same as that shown in FIG. 3 except that step S136 is output to output a control signal for opening the negative pressure introduction valve 102 after outputting a control signal for closing the air introduction valve 103. 3 are assigned the same reference numerals, and detailed descriptions thereof are omitted.

  That is, when an abnormality is detected, the atmospheric pressure introduction valve 103 is closed in step S136, and then the negative pressure introduction valve 102 is opened, so that negative pressure is applied to the piston rod 15d side chamber in the cylinder 15a. be introduced. In this way, the pressure difference between the chambers defined by the piston 15b is controlled, and the pressure in the chamber on the piston rod 15d side is controlled to be lower than the pressure in the other chamber, so that the piston 15b The return spring 14 is forcibly returned to the initial position, and the return spring 14 is fixed in the fully extended state.

Next, the operation of this embodiment will be described.
It is assumed that the driver is not operating a brake and is in a non-braking state. In this case, since the brake pedal 1 is not depressed, the master cylinder 2 is in the state shown in FIG. At this time, the master cylinder cut valves 3a and 3b are closed, the system shutoff valve 10 and the stroke simulator cut valve 13 are opened, the negative pressure introduction valve 102 is closed, and the air introduction valve 103 is opened. ing.

  From this state, when the driver depresses the brake pedal 1 to perform a braking operation, the air introduction valve 103 is in an open state, so that the piston 15b is pushed and the return is performed as shown in FIG. A displacement B of the spring 14 and a displacement A on the primary side of the master cylinder are generated. Since the master cylinder cut valve 3a is closed, the secondary side of the master cylinder is not displaced.

  On the other hand, when an abnormality occurs in the non-braking state shown in FIG. 5A, the process proceeds to step S3 based on the determination in step S2. Then, in the failure time control process shown in FIG. 6, the air introduction valve 103 is closed, and then the negative pressure introduction valve 102 is opened, so that the piston 15b and the return spring 14 are connected to each other as shown in FIG. ) Is fixed. Therefore, in this state, when the driver depresses the brake pedal 1 to perform braking, the return spring 14 is not displaced and pressure is applied to the piston of the master cylinder 2, so that the loss stroke due to the return spring 14 is eliminated. Thus, an appropriate braking force according to the depression of the brake pedal 1 can be obtained.

  Further, when an abnormality occurs in the braking state shown in FIG. 5B, the atmospheric introduction valve 103 is closed in the failure time control process, and then the negative pressure introduction valve 102 is opened. The negative pressure is introduced into the chamber on the piston rod 15d side of the cylinder 15a, and the piston 15b is returned to the initial position. At this time, since the depression force is applied to the brake pedal 1, the piston 15b is not displaced as shown in FIG. 5C, and the external cylinder 15a and the rod 15c are displaced to apply pressure to the master cylinder 2. It will be. That is, the stroke amount C of the master cylinder 2 is the sum of the primary displacement A and the return spring displacement B. Note that, when an abnormality occurs, the master cylinder cut valve 3a is controlled to be in an open state, so that displacement also occurs on the secondary side of the master cylinder.

As described above, in the second embodiment, the return spring portion includes the air introduction hole, the negative pressure introduction valve, and the air introduction valve, and these are used to fix the piston that is energized by the return spring when an abnormality occurs. Since it was set as the structure, the loss stroke for the return spring at the time of abnormality occurrence can be eliminated similarly to the first embodiment described above, and an appropriate braking force can be obtained.
In addition, since the negative pressure introduction valve is connected to the engine, it is possible to introduce negative pressure to the return spring if the engine is operating. Even in such a case, the piston can be fixed, and an appropriate braking force can be ensured even when an abnormality occurs during traveling.

  In the second embodiment, the case where the piston is fixed at the initial position by introducing the negative pressure has been described. However, the present invention is not limited to this, and the return return spring 14 in the cylinder 15a is arranged. A positive pressure introduction valve and an air introduction valve are provided in the chamber on the side where the air is provided, and an air introduction hole is provided in the other chamber. The piston may be fixed at the initial position by introducing a positive pressure.

Next, a third embodiment of the present invention will be described.
In the third embodiment, the piston is fixed using a permanent magnet and an electromagnet when an abnormality occurs in the first embodiment described above, whereas an external permanent magnet is used instead of the electromagnet. Is.
That is, as shown in FIG. 7 for the configuration of the return spring portion in the third embodiment, the electromagnet 17 shown in FIG. 4 is changed to a movable external permanent magnet 201 installed in the vicinity of the cylinder 15a. ing.
The external permanent magnet 201 is fixed by a spring at an initial position where no magnetic force is exerted on the permanent magnet 16 when normal, and is restored to the permanent magnet 16 by the restoring force of the spring attached to the external permanent magnet 201 when an abnormality occurs. On the other hand, it is configured to move to a position where the magnetic force is exerted.

FIG. 8 is a flowchart showing a processing procedure of the failure time control process executed in step S3 of FIG. 2 in the third embodiment. In the failure time control process of FIG. 3, the process of step S36 is performed. Except for being replaced with step S236 for operating the external permanent magnet 201, the same processing as in FIG. 3 is performed, and the same reference numerals are given to the corresponding portions with FIG. 3, and the detailed description thereof is omitted. .
That is, when an abnormality is detected, the piston 15b is forcibly returned to the initial position by moving the external permanent magnet 201 to a position where the magnetic force is applied to the permanent magnet 16 in step S236, and the return spring 14 is moved. It will be fixed in the fully extended state.

Next, the operation of this embodiment will be described.
It is assumed that the driver is not operating a brake and is in a non-braking state. In this case, since the brake pedal 1 is not depressed, the master cylinder 2 is in the state shown in FIG. At this time, the master cylinder cut valves 3 a and 3 b are closed, the system shutoff valve 10 and the stroke simulator cut valve 13 are opened, and the external permanent magnet 201 is in an initial position where no magnetic force is exerted on the permanent magnet 16. It is fixed.

  From this state, when the driver depresses the brake pedal 1 to perform a braking operation, the piston 15b is pushed, and the displacement B of the return spring 14 and the displacement of the primary side of the master cylinder as shown in FIG. 7B. A occurs. Since the master cylinder cut valve 3a is closed, the secondary side of the master cylinder is not displaced.

  On the other hand, when an abnormality occurs in the non-braking state shown in FIG. 7A, the process proceeds to step S3 based on the determination in step S2. In the failure time control process shown in FIG. 8, the external permanent magnet 201 is actuated and moved to a position where a magnetic force is exerted on the permanent magnet 16, whereby the piston 15b and the return spring 14 are moved to the position shown in FIG. It is fixed in the state of a). Therefore, in this state, when the driver depresses the brake pedal 1 to perform braking, the return spring 14 is not displaced and pressure is applied to the piston of the master cylinder 2, so that the loss stroke due to the return spring 14 is eliminated. Thus, an appropriate braking force according to the depression of the brake pedal 1 can be obtained.

  When an abnormality occurs in the braking state shown in FIG. 7B, the external permanent magnet 201 is actuated in the control process at the time of failure, so that a magnetic force is exerted on the permanent magnet 16 and the piston 15b. Is returned to the initial position. At this time, since the depression force is applied to the brake pedal 1, the piston 15b is not displaced as shown in FIG. 7C, and the external cylinder 15a and the rod 15c are displaced to apply pressure to the master cylinder 2. It will be. That is, the stroke amount C of the master cylinder 2 is the sum of the primary displacement A and the return spring displacement B. Note that, when an abnormality occurs, the master cylinder cut valve 3a is controlled to be in an open state, so that displacement also occurs on the secondary side of the master cylinder.

As described above, in the third embodiment, the return spring portion includes the permanent magnet and the external permanent magnet, and the piston is fixed when an abnormality occurs using the return magnet. Therefore, the first and second described above are used. Similar to the embodiment, it is possible to eliminate a loss stroke corresponding to the return spring when an abnormality occurs, and to obtain an appropriate braking force.
In addition, since an external permanent magnet is used to return the piston in the event of an abnormality to the initial position, a separate power source is not required, and even if an external power source cannot be obtained in the event of an abnormality, a return spring is always provided. It can be fixed, and an appropriate braking force can be obtained without a loss stroke.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, sliding of the piston with respect to the cylinder is restricted using a stopper.
That is, as shown in the schematic configuration diagram in the fourth embodiment in FIG. 9, in the schematic configuration diagram in the first to third embodiments described above, an accumulator 20 for accumulating the hydraulic pressure of the pump 9 is provided, and the cylinder 15a. And the accumulator 20 are connected via a normally closed solenoid valve (standby closing) 21, the cylinder 15 a and the reservoir 8 are connected via a normally closed solenoid valve (standby closing) 22, and the return spring portion is Except that the configuration is changed to the configuration shown in FIG. 10 described later, the configuration is the same as in FIG. 1, and the same reference numerals are given to the portions having the same configuration as in FIG. 1, and the detailed description thereof is omitted. To do.

  The accumulator 20 is always on standby with the pressure accumulated by the pump 9, and when a failure occurs, the normally closed solenoid valve 21 is opened, so that the hydraulic pressure of the accumulator 20 is introduced into the cylinder 15a. It is comprised so that. Further, when the failure state is shifted to the state in which the failure is eliminated, the normally closed solenoid valve 21 is closed and the normally closed solenoid valve 22 is opened, so that the hydraulic pressure in the cylinder 15a is discharged to the reservoir 8, and the cylinder After the hydraulic pressure in 15a is discharged, the normally closed electromagnetic valve 22 is closed to return to the normal state. The accumulator 20 and the normally closed electromagnetic valve 21 constitute a hydraulic pressure introducing means.

  FIG. 10 is a diagram illustrating a configuration of a return spring portion in the fourth embodiment. The cylinder 15 a includes a pedestal 23 protruding in the inner diameter direction at the center thereof, and one end of a return spring 14 is connected to the pedestal 23. That is, the return spring 14 is disposed on the brake pedal 1 side of the base 23 in the cylinder 15a.

  Further, on the master cylinder side of the pedestal 23, a stopper 24 is urged toward the master cylinder side by a stopper return spring 25 and is slidably disposed in the cylinder 15a. The stopper 24 has a back surface portion 24a as a piston portion having substantially the same cross-sectional shape and a predetermined thickness as the cylinder 15a, and extends from the center of the back surface portion 24a toward the piston 15b. And a pin 24b having a diameter smaller than the inner diameter of the spring 14. The pin 24b has a length equivalent to the length from the base 23 to the piston 15b in the non-braking state.

In normal operation, the piston 15b is disposed at a position where the stroke is possible, for example, the back surface 24a is brought into contact with the bottom of the cylinder 15a on the master cylinder side.
When a failure occurs, as described above, the normally closed solenoid valve 21 is opened and the hydraulic pressure is introduced into the cylinder 15a. At this time, of the chamber formed in the cylinder 15a by the back surface portion 24a, the liquid is placed between the chamber on the opposite side of the piston 15b, that is, between the bottom of the cylinder 15a on the master cylinder side and the back surface portion 24a of the stopper 24 (the back portion of the stopper 24). When the pressure is introduced, the stopper 24 moves in the cylinder 15a toward the brake pedal. This configuration corresponds to the stopper moving means.

  The stopper 24 is movable until the back surface portion 24a comes into contact with the pedestal 23. When the back surface portion 24a comes into contact with the pedestal 23, the brake pedal side end of the pin 24b is in an initial state when the piston 15b is not braked. It is configured to push back to the position. That is, when a failure occurs, sliding of the piston 15b with respect to the cylinder 15a is restricted by moving the stopper 24 toward the brake pedal.

  When the failure is resolved, the normally closed solenoid valve 21 is closed and the normally closed solenoid valve 22 is opened, whereby the hydraulic pressure in the cylinder 15a is discharged to the reservoir 8, and the spring reaction force of the stopper return spring 25 is released. As a result, the stopper 24 moves to the master cylinder side and returns to the initial position in the normal state. Thereby, piston 15b returns to the state which can slide in cylinder 15a.

Next, the operation of this embodiment will be described.
It is assumed that the driver is not operating a brake and is in a non-braking state. In this case, since the brake pedal 1 is not depressed, the master cylinder 2 is in the state shown in FIG. At this time, the stopper 24 is stuck to the bottom of the cylinder 15a on the master cylinder side by the urging force of the stopper return spring 25. Further, the normally closed solenoid valve 21 and the normally closed solenoid valve 22 are in a closed state (standby state), and the hydraulic pressure generated by the power hydraulic pressure source 9 is accumulated in the accumulator 20.

  From this state, when the driver depresses the brake pedal 1 to perform a braking operation, the piston 15b is pushed, and the displacement of the return spring 14 and the displacement of the master cylinder (not shown) on the primary side occur. Since the master cylinder cut valve 3a is closed during normal operation, the secondary side of the master cylinder is not displaced.

On the other hand, when a failure occurs in the non-braking state shown in FIG. 10 (a), the normally closed solenoid valve 21 is controlled to be in an open state, and the working fluid accumulated in the accumulator 20 is retained by the stopper 24 in the cylinder 15a. Introduced in the back. As a result, the stopper 24 strokes toward the brake pedal, and the brake pedal side end of the pin 24b continues to push the back surface of the piston 15b as shown in FIG. 10B, so that the piston 15b and the return spring 14 are in this state. Fixed.
Therefore, in this state, when the driver depresses the brake pedal 1 to perform braking, the return spring 14 is not displaced and pressure is directly applied to the piston of the master cylinder 2, so that the loss stroke by the return spring 14 is reduced. Thus, an appropriate braking force corresponding to the depression of the brake pedal 1 can be obtained.

  When a failure occurs in the braking state, the working fluid accumulated in the accumulator 20 is introduced into the back of the stopper 24 in the cylinder 15a, so that the stopper 24 moves to the brake pedal side. At this time, since the stepping force is applied to the brake pedal 1, the piston 15b is not displaced, and the external cylinder 15a and the rod 15c are displaced to the master cylinder side, and pressure is applied to the master cylinder 2. That is, the stroke amount of the master cylinder 2 is the sum of the primary displacement and the return spring displacement. Therefore, if the pedal stroke is held when a failure occurs, the braking force that has already been pedaled can be generated immediately.

As described above, in the fourth embodiment, since the stopper is moved when a failure occurs, the sliding of the piston with respect to the cylinder can be surely restricted, and the loss stroke corresponding to the return spring can be eliminated.
In addition, when a failure occurs, the hydraulic pressure is introduced into the cylinder by the pressure accumulated during normal operation, so that the stopper can be reliably moved and an external power source is not required.

  In the fourth embodiment, the case where the stopper 24 is moved to the brake pedal side when a failure occurs due to the pressure accumulated during normal operation has been described. However, the present invention is not limited to this, and FIG. As shown, explosive 50 may be enclosed between cylinder 15a and the back surface of stopper 24, explosive explosive 50 may be expelled when a failure occurs, and stopper 24 may be moved to the brake pedal side by the explosive pressure. This corresponds to the hydraulic pressure introducing means. Thereby, when a failure occurs, the stopper 24 can be reliably moved to the brake pedal side by the explosive pressure of the explosive 50, and the sliding of the piston 15b with respect to the cylinder 15a can be reliably regulated.

  Further, as shown in FIG. 11B, the stopper 24 may be moved to the brake pedal side when a failure occurs by a mechanism using a linear guide including a speed reducer 51 and a motor 52. Thus, when a failure occurs, the stopper 24 can be reliably moved to the brake pedal side by the power source of the motor 52, and the sliding of the piston 15b with respect to the cylinder 15a can be reliably regulated.

  Furthermore, in the fourth embodiment, as shown in FIG. 12, a slide guide portion 26 of the stopper 24 may be provided on the stopper 24 side of the piston 15b. The slide guide portion 26 is opened to the stopper 24 side, and has a cross-sectional area such that the pin 24b of the stopper 24 can slide smoothly. With such a configuration, as shown in FIG. 12B, when the failure occurs, it is possible to make a stroke toward the brake pedal without twisting the stopper 24, and to reliably prevent contact between the return spring 14 and the stopper 24. Can do. Further, when such a slide guide is not provided, the thickness of the back surface portion 24a of the stopper 24 becomes a slide guide. Therefore, the back surface portion 24a requires a predetermined thickness, but the slide guide is provided on the piston 15b. Thus, the thickness of the back surface portion 24a of the stopper 24 can be reduced.

Next, a fifth embodiment of the present invention will be described.
In the fifth embodiment, a mechanism for mechanically locking the stopper with respect to the cylinder when the stopper is stroked to the brake pedal side when a failure occurs is provided in the fourth embodiment described above. .
That is, as shown in FIG. 13, the configuration of the return spring portion in the fifth embodiment is provided with a wedge 24c on the side surface of the back surface portion 24a of the stopper 24 and a hook for engaging with the wedge 24c on the inner peripheral surface of the cylinder 15a. Except that 27 is formed, it has the same configuration as in FIG. 12, and the same reference numerals are given to portions having the same configuration as in FIG. 12, and the detailed description thereof is omitted.

  The hook 27 provided on the inner peripheral surface of the cylinder 15a is formed at a position where it engages with a wedge 24c provided on the back surface portion 24a when the stopper 24 strokes to the position of the base 23 when a failure occurs. With such a configuration, when the stopper 24 strokes when a failure occurs, the stopper 24 is locked by the wedge 24c and the hook 27 so that the stopper 24 does not slide relative to the cylinder 15a. This configuration corresponds to the stopper fixing means.

  By the way, when the hydraulic pressure accumulated during normal operation or the explosive pressure of explosives is used as a means for stroking the stopper 24 when a failure occurs, there is airtightness for maintaining the pressure after the stopper 24 is stroked. Required. Further, when an airtight leak or the like of the pressure supply source occurs, there is a problem that the stroke position of the stopper 24 moves backward to the master cylinder side and the stroke of the piston 15b becomes possible when the brake pedal 1 is operated.

However, by providing the locking mechanism as in this embodiment, if a force until the stopper 24 is locked when a failure occurs is input, even if airtight leakage or the like subsequently occurs, the cylinder The state where the sliding of the piston 15b with respect to 15a is regulated can be reliably maintained.
In addition, when a mechanism using a linear guide is used as a means for stroking the stopper 24 when a failure occurs, power must be continuously supplied to maintain the state after the stopper 24 is stroked. By providing the lock mechanism as in the present embodiment, it is not necessary to supply power after the stopper 24 is in the locked state.

  As described above, in the fifth embodiment, a lock mechanism is provided to lock the stopper with respect to the cylinder when the stopper is stroked toward the brake pedal when a failure occurs. The cost for measures against airtight leakage when pressure is used can be reduced, and power supply can be reduced when a mechanism using a linear guide is applied as means for stroking the stopper when a failure occurs.

In addition, since a wedge is provided on the side surface of the back surface of the stopper and a hook is provided on the inner peripheral surface of the cylinder, and the wedge and the hook are engaged with each other, a locking mechanism is realized, so that the stopper can be reliably locked.
In the fifth embodiment, the description has been given of the case where the stopper locking mechanism is realized by the wedge 24c on the back surface of the stopper and the hook 27 of the cylinder, but the present invention is not limited to this. Instead of providing the hook 27, a press-fitting allowance may be provided between the outer diameter of the back portion 24a of the stopper and the inner diameter of the cylinder 15a. With such a configuration, when the stopper 24 strokes toward the brake pedal when a failure occurs, the stopper 24 is press-fitted into the cylinder 15a, and the stopper 24 can be reliably locked.

Next, a sixth embodiment of the present invention will be described.
In the sixth embodiment, the outer peripheral surface of the slide guide portion and the cylinder base are formed in a wedge shape, thereby realizing a stopper locking mechanism.
That is, as shown in FIG. 14 in the configuration of the return spring portion in the sixth embodiment, the pedestal 23 of the cylinder 15a has a wedge shape, and the stopper side end portion opens in the outer diameter direction of the cylinder 15a. 12 has a configuration similar to that of FIG. 12 except that a wedge is provided on the outer peripheral surface of the slide guide portion 26 and the stopper 24 is formed in a tapered shape. Reference numerals are assigned and detailed description thereof is omitted.

The slide guide portion 26 is provided with an opening / closing mechanism in which the axial cut of the cylinder 15a is formed in at least two locations, and the stopper 24 side can be opened in the outer diameter direction. And the wedge for meshing | engaging with the base 23 is formed in the outer peripheral surface of this slide guide part 26 at equal intervals in the axial direction.
Under normal conditions, the wedge of the slide guide portion 26 and the wedge of the base 23 are not engaged with each other, and the piston 15b slides in the cylinder 15a in response to the depression of the brake pedal 1. On the other hand, when a failure occurs, the stopper 24 strokes, and the slide guide portion 26 is opened in the outer diameter direction by the taper of the stopper 24. At this time, the wedge provided on the slide guide portion 26 and the wedge of the base 23 are engaged with each other.

That is, in the non-braking state where the driver does not operate the brake pedal, the return spring portion is in the state shown in FIG. When the driver depresses the brake pedal from this state, the wedge of the slide guide portion 26 and the wedge of the pedestal 23 do not mesh with each other, and the piston 15b strokes toward the master cylinder.
If a failure occurs in this state, the stopper 24 is moved to the brake pedal 1 side. Since the stopper 24 is formed in a tapered shape, the slide guide portion 26 opens in the outer diameter direction as the stopper 24 is inserted into the slide guide portion 26. As a result, the wedge of the slide guide portion 26 and the wedge of the pedestal 23 are engaged with each other, and the state shown in FIG.

Thereby, sliding of the piston 15b with respect to the cylinder 15a is restricted, and the stopper 24 is mechanically locked in a state where it is inserted into the slide guide portion 26.
By the way, in the fifth embodiment described above, once a failure occurs, the stopper 24 continues to be locked. However, in order to release the lock, the return spring portion must be disassembled or replaced. Therefore, there is a problem that the cost for parts replacement increases.

  Therefore, in this embodiment, the locked state of the stopper 24 when a failure occurs can be released. Specifically, when returning from the failed state, a force is applied to the stopper 24 to pull it back to the master cylinder side, which is the direction of the initial position in the normal state. The pulling force may be a motor driving source, a negative pressure tension and a spring reaction force. This configuration corresponds to the stopper fixing release means.

  In the locked state shown in FIG. 14B, if a force for pulling away from the slide guide portion 26 is applied to the stopper 24, the stopper 24 is returned to the initial position. Since the stopper 24 is formed in a taper shape, as the stopper 24 strokes toward the master cylinder, the slide guide portion 26 gradually closes in the inner diameter direction, and the engagement with the base 23 is released. As a result, the piston 15b can slide in the cylinder 15a in response to the depression of the brake pedal 1, and returns to a normal state.

  As described above, in the sixth embodiment, by opening the slide guide portion in the outer diameter direction using the taper of the stopper, the wedge formed on the slide guide portion and the wedge on the base of the cylinder are engaged with each other. Since the sliding of the piston with respect to is regulated, the time until the regulation of the sliding of the piston at the time of the failure is fast, and the delay in switching the rod at the time of the failure can be eliminated.

In addition, since the stopper is tapered, if the stopper strokes when a failure occurs, the stopper can be press-fitted into the slide guide portion and can be locked at that position.
Furthermore, by inputting the force that pulls the stopper away from the piston, the locked state can be released, allowing parts to be reused even after the failure has been resolved, reducing the cost of parts replacement. can do.

Next, a seventh embodiment of the present invention will be described.
In the seventh embodiment, a stopper locking mechanism and a lock releasing mechanism are provided in the event of a failure, and when a failure occurs in a braking state, a braking force that has already been pedal stroked is generated. It is.
That is, as shown in FIG. 15 in the configuration of the return spring portion in the seventh embodiment, the slide guide portion 26 has an opening / closing mechanism that can be opened in the outer diameter direction of the cylinder 15a. Further, a lock portion 26a for engaging with the pedestal 23 of the cylinder 15a is provided at the end of the slide guide portion 26 on the master cylinder side.

  A spherical protrusion 24d is provided on the brake pedal side end of the pin 24b of the stopper 24. When the stopper 24 strokes toward the brake pedal when a failure occurs, the protrusion 24d enters the slide guide part 26. The diameter of the protrusion 24d is formed larger than the diameter of the slide guide part 26 in a normal state, and the slide guide part 26 is configured to open in the outer diameter direction when the protrusion 24d enters the slide guide part 26. Yes.

When the protruding portion 24d of the stopper 24 is inserted to the back of the slide guide portion 26, the lock portion 26a at the tip of the slide guide portion and the pedestal 23 are engaged with each other, and the protruding portion 24d of the stopper 24 is at the base of the slide guide portion 26. It is fixed to the formed stopper lock portion 26b.
That is, in the non-braking state where the driver does not operate the brake pedal, the return spring portion is in the state shown in FIG. In this state, since there is no place where the lock portion 26a is engaged, when the driver steps on the brake pedal, the piston 15b strokes toward the master cylinder.

  When a failure occurs in this braking state, the stopper 24 is moved to the brake pedal 1 side. Since a protrusion 24d having a diameter larger than the diameter of the slide guide 26 is formed at the brake pedal side end of the stopper 24, the piston 15b is pushed back to the initial position by the protrusion 24d. At this time, since the stepping force is applied to the brake pedal 1, the piston 15b is not displaced, and the external cylinder 15a and the rod 15c are displaced toward the master cylinder to apply pressure to the master cylinder 2.

  The stopper 24 is further stroked to the brake pedal side even after the piston 15b is pushed back to the initial position, and the protrusion 24d is inserted while opening the slide guide portion 26 in the outer diameter direction. When the protruding portion 24d reaches the back surface of the piston 15b, the lock portion 26a meshes with the pedestal 23, so that a force for closing the opening / closing mechanism is generated in the slide guide portion 26 by the reaction force from the pedestal 23. Due to the force for closing the opening / closing mechanism, the protruding portion 24d is kept in the stopper lock portion 26b. As a result, the state shown in FIG.

In order to release the locked state of the stopper 24, a force for pulling away from the stopper 24 may be applied to the piston 15b. The pulling force may be a motor driving source, a negative pressure tension and a spring reaction force.
That is, in the locked state shown in FIG. 15B, if a force is applied to pull back the piston 15b toward the brake pedal, the locking portion 26a is first disengaged from the pedestal 23 so that the reaction force from the pedestal 23 is eliminated. The force for closing the opening / closing mechanism of the slide guide portion 26 is eliminated. Thereby, since the force which presses the projection part 24d becomes weak, if the stopper 24 is returned to the master cylinder side, it can return to a normal state.

Thus, in the seventh embodiment, when the stopper is moved when a failure occurs, the stopper can be fixed to the cylinder, and when the failure is resolved, the fixing can be released. Similar to the sixth embodiment, it is possible to reduce the cost for parts replacement.
In addition, when a failure occurs, the stopper regulates sliding after returning the piston to the initial position, so when a failure occurs in the braking state, the braking force that has already been pedal stroked is generated immediately. And an appropriate braking force can be obtained.

Next, an eighth embodiment of the present invention will be described.
In the eighth embodiment, the spring characteristic of the return spring is changed between when it is normal and when a failure occurs.
That is, as shown in FIG. 16 showing the configuration of the master cylinder and the return spring portion in the eighth embodiment, the rod 15c is connected to the cancel piston 28a disposed on the brake pedal side of the piston 2c of the master cylinder. A cancel spring chamber 28b is formed on the brake pedal side of the pressure generating chamber 2a by the cancel piston 28a.

A cancel spring 28c having a spring constant larger than that of the return spring 14 is provided in the cancel piston chamber 28b. In the cancel piston chamber 28b, a magnet 28d is installed on the piston 2c and an electromagnet 28e is installed on the cancel piston 28a.
In the normal state, as shown in FIG. 16A, the electromagnet 28e is operated to couple the magnet 28d and the electromagnet 28e by magnetic force, and the distance between the piston 2c and the cancel piston 28a is minimized. At this time, the cancel spring 28c is crushed by the piston 2c and the cancel piston 28a so as not to operate.

  When a failure occurs, the coupling between the piston 2c and the cancel piston 28a is released by cutting off the energization of the electromagnet 28e. Here, since the spring constant of the cancel spring 28c is larger than the spring constant of the return spring 14 as described above, the return spring 14 is crushed by releasing the cancel piston 28a, and as shown in FIG. 16B, the cancel spring 28c. Is activated, and the return spring 14 is deactivated.

That is, when a failure occurs, the spring interposed between the brake pedal 1 and the master cylinder 2 is switched from the return spring 14 to the cancel spring 28c. This configuration corresponds to the spring switching means. This is equivalent to changing the spring characteristics of the return spring between the normal time and the time of failure.
With such a configuration, the stepping force applied to the brake pedal 1 by the driver is input to the piston 2c via the return spring 14 and the cancel piston 28c. In FIG. 16, the return spring 14 and the cancel piston 28 c constitute a return spring that inputs a depression force corresponding to the depression amount of the brake pedal 1 to the master cylinder 2.

FIG. 17A is a diagram showing the relationship between the pedal stroke of the brake pedal and the master cylinder pressure. As shown by the broken line in FIG. 17B, in the conventional device, the stroke of the return spring 14 increases proportionally as the pedal stroke increases until the full stroke is reached.
Therefore, as shown by the broken line in FIG. 17A, the master cylinder pressure in the conventional device rises gently according to the pedal stroke until the return spring 14 reaches the full stroke, and the return spring 14 becomes the full stroke. After that, it rises with the same slope as the normal characteristic shown by the alternate long and short dash line. That is, there is a problem that a loss stroke of 14 minutes occurs for the return spring.

In the present embodiment, when a failure occurs, the spring interposed between the brake pedal 1 and the master cylinder 2 is switched from the return spring 14 to the cancel spring 28c having a large spring constant, so that the solid line in FIG. In addition, the stroke of the return spring 14 is always a full stroke.
As a result, the input (push rod thrust) to the master cylinder with respect to the pedal stroke increases, and as shown by the solid line in FIG. 17 (a), the rising gradient of the master cylinder pressure with respect to the pedal stroke becomes steep. It can be set as the characteristic equivalent to the normal time shown. That is, the characteristic gradient in the conventional apparatus is changed so as to approach the characteristic gradient in the normal state.

As described above, in the eighth embodiment, since the spring characteristic of the return spring is changed when a failure occurs, the master cylinder push rod thrust with respect to the pedal stroke can be increased, and the loss stroke corresponding to the return spring can be reduced. Can do.
In addition, the return spring is composed of two springs with different reaction force characteristics, and when a failure occurs, the spring with the higher reaction force is activated and the spring with the lower reaction force is deactivated, increasing the spring gain. Thus, it can be made closer to a rigid body, and the loss stroke can be reduced.
Furthermore, since this embodiment can simplify the structure, high-precision component processing is not required, and the design man-hours can be greatly reduced.

  In the eighth embodiment, the case where the cancel piston and the cancel spring are provided in the master cylinder has been described. However, the present invention is not limited to this, and as shown in FIG. 28a and a cancel spring 28c may be provided. Also in this case, as shown in FIG. 18 (a), the magnet 28d and the electromagnet 28e are coupled so that the distance between the bottom of the cylinder 15a on the master cylinder side and the cancel piston 28a becomes the shortest as shown in FIG. When it occurs, as shown in FIG. 18B, the energization of the electromagnet 28e may be cut off to release the coupling between the two. As a result, when a failure occurs, the spring interposed between the brake pedal 1 and the master cylinder 2 is switched from the return spring 14 to the cancel spring 28c having a large spring constant, thereby reducing the loss stroke for the return spring. can do.

  In the eighth embodiment, a case has been described in which the return spring for inputting the depression force corresponding to the depression amount of the brake pedal to the master cylinder is constituted by two springs of the return spring 14 and the cancel spring 28c. However, the present invention is not limited to this, and it may be configured by three or more springs having different reaction force characteristics.

Next, a ninth embodiment of the present invention will be described.
In the ninth embodiment, the return spring is forcibly crushed so as not to function when a failure occurs.
That is, as shown in FIG. 19, the configuration of the master cylinder and the return spring portion in the ninth embodiment is screwed into the cylinder 29a with the motor 29a, the spiral shaft 29b driven by the motor 29a, and the spiral shaft 29b. A cancel piston 29c that moves in the axial direction in the cylinder 15a by driving the spiral shaft 29b is disposed.

  One end of the return spring 14 is connected to the cancel piston 29c, and when it is normal, as shown in FIG. 19A, the cancel piston 29c is moved to the motor 29a side. Try to be stretched. Further, when normal, the cancel piston 29c is fixed by disabling the motor 29a and not driving the spiral shaft 29b.

  When a failure occurs, the motor 29a is operated to rotate the spiral shaft 29b. At this time, the cancel piston 29c is rotated in the direction of moving to the brake pedal side. Accordingly, as shown in FIG. 19B, the cancel piston 29c moves to the brake pedal side, and the return spring 14 is crushed. The motor 29a is operated until the return spring 14 is completely crushed. This configuration corresponds to the spring compression means.

When the return spring 14 is completely crushed, the operation of the motor 29a is stopped, and the movement of the cancel piston 29c is stopped and fixed. Therefore, when a braking operation is performed in this state, the return spring 14 is in a full stroke state, and thus pressure is directly applied to the piston of the master cylinder 2.
That is, when a failure occurs, the spring interposed between the brake pedal 1 and the master cylinder 2 is switched from the return spring 14 to a complete rigid body, so that the sliding of the piston 15b with respect to the cylinder 15a is completely restricted. The pedal stroke can be transmitted directly to the master cylinder.

FIG. 20A is a diagram showing the relationship between the pedal stroke of the brake pedal and the master cylinder pressure. As shown by the broken line in FIG. 20B, in the conventional device, the stroke of the return spring 14 increases proportionally as the pedal stroke increases until the full stroke is reached.
Therefore, as shown by the broken line in FIG. 20A, the master cylinder pressure in the conventional apparatus rises with the same gradient as the normal characteristic indicated by the one-dot chain line after the return spring 14 reaches the full stroke. Become.

  In the present embodiment, when a failure occurs, the spring interposed between the brake pedal 1 and the master cylinder 2 is switched from the return spring 14 to a completely rigid body, and therefore, as shown by the solid line in FIG. The characteristic of the master cylinder pressure with respect to can be made equal to the normal characteristic indicated by the one-dot chain line. That is, the characteristic in the conventional apparatus is offset so as to approach the characteristic gradient in the normal state.

As described above, in the ninth embodiment, by applying the motor and the spiral shaft, the spring characteristic of the return spring can be changed and a complete rigid body can be obtained when a failure occurs. The pressure characteristic can be brought into an optimum state.
In the ninth embodiment, the case where the return spring is completely crushed when a failure occurs has been described. However, the present invention is not limited to this. That is, if the return spring can be shortened even a little, the initial set load of the return spring increases, so that the master cylinder pressure characteristic can be brought close to the normal characteristic.

In each of the above embodiments, the case where the depression amount of the brake pedal is detected by applying the master cylinder pressure sensor or the stroke sensor is described, but the present invention is not limited to this, and the depression force applied to the brake pedal is not limited to this. The amount of depression of the brake pedal may be detected by detecting with a torque sensor such as a magnetostrictive sensor or a strain gauge.
Further, in each of the above embodiments, the case where the hydraulic pump 9b driven by the electric motor 9a is applied as the braking pressure generating means has been described. However, the present invention is not limited to this, and the rotational force of the engine is used. The hydraulic pump may be driven to rotate.

Further, in each of the above embodiments, the case where the piston is connected to the brake pedal side end of the return spring has been described. However, the present invention is not limited to this, and the piston is connected to the master cylinder side end of the return spring. A cylinder in which the piston is slidably disposed may be connected to the other end.
Further, in each of the above embodiments, a case has been described in which a means using a permanent magnet and an electromagnet, a means using a negative pressure introduction valve, and the like are individually provided as the sliding restriction means, but the invention is not limited to this. The sliding restriction means in the first to seventh embodiments described above may be provided in combination.

It is a schematic structure figure showing an embodiment of the present invention. It is a flowchart which shows the brake fluid pressure control process performed with a control unit. It is a flowchart which shows the control processing at the time of failure in 1st Embodiment. It is a figure explaining the operation | movement in 1st Embodiment. It is a figure explaining the operation | movement in 2nd Embodiment. It is a flowchart which shows the control processing at the time of a failure in 2nd Embodiment. It is a figure explaining the operation | movement in 3rd Embodiment. It is a flowchart which shows the control processing at the time of a failure in 3rd Embodiment. It is a schematic block diagram which shows 4th Embodiment. It is a figure explaining the operation | movement in 4th Embodiment. It is a figure explaining another example of the means to move a stopper. It is a figure explaining another example of 4th Embodiment. It is a figure explaining the operation | movement in 5th Embodiment. It is a figure explaining the operation | movement in 6th Embodiment. It is a figure explaining the operation | movement in 7th Embodiment. It is a figure explaining the operation | movement in 8th Embodiment. It is a figure which shows the master cylinder pressure characteristic in 8th Embodiment. It is a figure explaining another example of 8th Embodiment. It is a figure explaining the operation | movement in 9th Embodiment. It is a figure which shows the master cylinder pressure characteristic in 9th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Master cylinder 3a, 3b Master cylinder cut valve 4a, 4b Normally open type solenoid valve 5a, 5b Wheel 6a, 6b Wheel cylinder 7a, 7b Master cylinder pressure sensor 8 Reservoir 9 Pump 10 System shutoff valve 11a, 11b Normally closed Solenoid valve 12 Stroke simulator 13 Stroke simulator cut valve 14 Return spring 15a Cylinder 15b Piston 15c Rod 16 Permanent magnet 17 Electromagnet 18 Stroke sensor 19a, 19b Wheel cylinder pressure sensor 20 Accumulator 23 Base 24 Stopper 25 Stopper return spring 26 Slide guide portion 28a Cancel Piston 28b Return spring chamber 28c Cancel spring 28d Magnet 28e Electromagnet 29a Motor 29b Spy Rushafuto 29c cancel piston 30 control unit 101 the air inlet holes 102 a negative pressure introducing valve 103 the air introducing valve 201 outside the permanent magnet

Claims (10)

A master cylinder that inputs a depressing force corresponding to the amount of depression of the brake pedal via a return spring and outputs a working fluid pressure for braking according to the input; a fluid pressure supply source that generates a predetermined working fluid pressure; , and a wheel cylinder for generating a braking force for braking the wheels when a predetermined condition is determined to be not established, the working fluid the master cylinder and cut and said wheel cylinder, is generated from the fluid pressure supply source When the braking force of the wheel cylinder is controlled by pressure and it is determined that the predetermined condition is satisfied, the master cylinder communicates with the wheel cylinder, and the wheel fluid is output by the working fluid pressure output from the master cylinder. In the brake control device that controls the braking force of the cylinder,
When it is determined that the piston connected to one end of the return spring, the cylinder connected to the other end of the return spring and the piston is slidably disposed, and the predetermined condition is satisfied, the cylinder Expansion and contraction restricting means for restricting expansion and contraction of the return spring by a slide restricting means for restricting sliding of the piston with respect to the permanent magnet, and the slide restricting means includes a permanent magnet installed on the piston and a piston of the cylinder A brake control device comprising: an electromagnet installed on the rod side; and operating the electromagnet to restrict sliding of the piston when it is determined that the predetermined condition is satisfied . A master cylinder that inputs a depressing force corresponding to the amount of depression of the brake pedal via a return spring and outputs a working fluid pressure for braking according to the input; a fluid pressure supply source that generates a predetermined working fluid pressure; A wheel cylinder that generates a braking force for braking the wheel, and when it is determined that a predetermined condition is not satisfied, the master cylinder and the wheel cylinder are disconnected, and the working fluid generated from the fluid pressure supply source When the braking force of the wheel cylinder is controlled by pressure and it is determined that the predetermined condition is satisfied, the master cylinder communicates with the wheel cylinder, and the wheel fluid is output by the working fluid pressure output from the master cylinder. In the brake control device that controls the braking force of the cylinder,
When it is determined that the piston connected to one end of the return spring, the cylinder connected to the other end of the return spring and the piston is slidably disposed, and the predetermined condition is satisfied, the cylinder Expansion and contraction restricting means for restricting expansion and contraction of the return spring by a slide restricting means for restricting sliding of the piston with respect to the piston, the slide restricting means includes a first permanent magnet installed on the piston, and A second permanent magnet movably installed in the vicinity of the cylinder, and when it is determined that the predetermined condition is satisfied, the second permanent magnet is magnetized against the first permanent magnet. The brake control device is characterized by restricting sliding of the piston by moving to a position covered by. A master cylinder that inputs a depressing force corresponding to the amount of depression of the brake pedal via a return spring and outputs a working fluid pressure for braking according to the input; a fluid pressure supply source that generates a predetermined working fluid pressure; A wheel cylinder that generates a braking force for braking the wheel, and when it is determined that a predetermined condition is not satisfied, the master cylinder and the wheel cylinder are disconnected, and the working fluid generated from the fluid pressure supply source When the braking force of the wheel cylinder is controlled by pressure and it is determined that the predetermined condition is satisfied, the master cylinder communicates with the wheel cylinder, and the wheel fluid is output by the working fluid pressure output from the master cylinder. In the brake control device that controls the braking force of the cylinder,
When it is determined that the piston connected to one end of the return spring, the cylinder connected to the other end of the return spring and the piston is slidably disposed, and the predetermined condition is satisfied, the cylinder Expansion and contraction restricting means for restricting expansion and contraction of the return spring by a slide restricting means for restricting sliding of the piston with respect to the stopper, and the slide restricting means includes a stopper member arranged to be movable in the cylinder; A stopper moving means for moving the stopper member, and when it is determined that the predetermined condition is satisfied, the stopper moving means moves the stopper member to the piston side to restrict the sliding of the piston. To do,
The stopper member has a piston portion defining the inside of the cylinder, and the stopper moving means is a liquid for introducing hydraulic pressure into a chamber on the opposite side of the piston among the chambers formed in the cylinder by the piston portion. A brake control device comprising pressure introducing means, wherein the hydraulic pressure introducing means introduces hydraulic pressure into a chamber opposite to the piston and moves the stopper member toward the piston. The brake control device according to claim 3, wherein the stopper moving unit drives a motor to move the stopper member to the piston side. 5. The brake according to claim 3, wherein the sliding regulating unit includes a stopper fixing unit that fixes the stopper member to the cylinder when the stopper member is moved by the stopper moving unit. Control device. The brake control device according to claim 5, wherein the sliding restricting unit includes a stopper fixing releasing unit that releases the fixing of the stopper member by the stopper fixing unit. The sliding restriction means has pressure control means for controlling the pressure of the chamber on the piston rod side among the chambers formed in the cylinder by the piston to be lower than the pressure of the other chamber, and the predetermined condition When it is determined that the pressure is satisfied, the pressure control means lowers the pressure in the chamber on the piston rod side to restrict sliding of the piston. The brake control device according to item. The pressure control means includes a negative pressure introduction valve installed in the chamber on the piston rod side, opens the negative pressure introduction valve to introduce a negative pressure into the chamber on the piston rod side, and the pressure in the chamber is reduced. The brake control device according to claim 7, wherein the brake control device is controlled so as to be lower than the pressure in the other chamber. A master cylinder that inputs a depressing force corresponding to the amount of depression of the brake pedal via a return spring and outputs a working fluid pressure for braking according to the input; a fluid pressure supply source that generates a predetermined working fluid pressure; A wheel cylinder that generates a braking force for braking the wheel, and when it is determined that a predetermined condition is not satisfied, the master cylinder and the wheel cylinder are disconnected, and the working fluid generated from the fluid pressure supply source When the braking force of the wheel cylinder is controlled by pressure and it is determined that the predetermined condition is satisfied, the master cylinder communicates with the wheel cylinder, and the wheel fluid is output by the working fluid pressure output from the master cylinder. In the brake control device that controls the braking force of the cylinder,
When it is determined that the predetermined condition is satisfied, the return spring includes expansion / contraction restriction means for restricting expansion / contraction of the return spring by a characteristic change means for changing a spring characteristic of the return spring, and the return spring has a plurality of different reaction force characteristics. When the characteristic changing means determines that the predetermined condition is satisfied, the spring having a high reaction force is activated and the spring having a low reaction force is deactivated, and the predetermined condition is not satisfied. A spring switching means for changing the spring characteristics of the return spring by switching the plurality of springs by operating a spring having a low reaction force and operating a spring having a low reaction force when it is determined that there is a spring; Brake control device. The characteristic changing means has a spring compression means for forcibly shrinking the return spring, and when it is determined that the predetermined condition is satisfied, forcibly shrinking the return spring with the spring compression means, The brake control device according to claim 9, wherein a spring characteristic of the return spring is changed.

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