JP2001315631A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the braking force from being excessively reduced in brake control in the case that an automatic parking brake and a hydraulic brake are simultaneously actuated during the travel of a vehicle. SOLUTION: In the case that a first braking force generating means actuated by the operation of a brake pedal, and a second braking force generating means actuated by a driving means, are simultaneously actuated during the travel of the vehicle, at least one control out of the control of a first braking force reducing means and the control of a second braking force reducing means is changed by a control changing means with respect to the case of only one of the first braking force generating means and second braking force generating means being actuated. This results in preventing the braking force from being educed more than necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device capable of applying an appropriate braking force to wheels of a vehicle.

[0002]

2. Description of the Related Art There is an automatic parking brake device that activates a parking brake by, for example, driving a motor by operating a switch or detecting a stopped state of a vehicle. The automatic parking brake device may be operated as a backup of, for example, a hydraulic brake operated by a brake pedal when the vehicle is running. When the automatic parking brake is actuated while the vehicle is running, the braking force may act and the wheels may be locked. When a locked state is detected, control may be performed to reduce the braking force of the automatic parking brake so as to release the locked state.

[0003]

By the way, among vehicles equipped with the above-mentioned automatic parking brake device, there is a vehicle equipped with an anti-lock brake system for performing anti-lock control. In this vehicle, for example, when the automatic parking brake is activated while the vehicle is running, the occupant may simultaneously depress the brake pedal to activate the hydraulic brake. In this case, when the locked state of the wheel is detected, the braking force of the automatic parking brake is controlled so as to release the locked state, and simultaneously the anti-lock control may be performed. In some cases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a brake when a wheel is locked when an automatic parking brake and a hydraulic brake are simultaneously operated during running of a vehicle. The control is to prevent the braking force from being reduced more than necessary.

[0005]

In order to achieve this object, a first aspect of the present invention is a first braking force generating means for generating a braking force on wheels in response to an operation of a brake pedal; Second braking force generating means for applying a braking force to at least one of a pair of left and right front wheels by a driving means, wheel rotation speed detecting means for detecting a rotation speed of the wheel, and wheel rotation speed detection First braking force reducing means for performing control to reduce the braking force of the first braking force generating means based on the rotation speed of the wheel detected by the means;
A second braking force reduction unit configured to perform control for reducing a braking force of the second braking force generation unit based on a wheel rotation speed detected by the wheel rotation speed detection unit; When the first braking force generation unit and the second braking force generation unit are simultaneously operated, at least one of the control of the first braking force reduction unit and the control of the second braking force reduction unit is controlled. The control is changed by the changing means when only one of the first braking force generating means and the second braking force generating means is operating.

In the apparatus according to the first aspect of the present invention, when the first braking force generating means by the operation of the brake pedal and the second braking force generating means by the driving means are simultaneously operated during running of the vehicle, Control of the first braking force reducing means and the second
At least one of the controls of the braking force reducing means is controlled by the control changing means, when only one of the first braking force generating means and the second braking force generating means is operating. Control changes. Therefore, it is possible to prevent the braking force from being reduced more than necessary.

According to a second aspect of the present invention, the control changing means according to the first aspect changes the control when it is determined that rotation of at least one of the pair of wheels is stopped. Features.

In the apparatus according to the second aspect of the present invention, the control changing means changes the control when it is determined that the rotation of at least one of the set of wheels is stopped. Frequency is reduced. Therefore, the durability of the control changing means can be improved.

A third aspect of the present invention is characterized in that the control changing means according to the first or second aspect limits the control of one of the braking force reducing means.

In the device according to the third aspect of the present invention, the control of the braking force reducing means is performed by the one braking force reducing means, but the control of the one braking force reducing means is restricted. Therefore, the vehicle can be braked with an appropriate braking force by a simple control. Here, the restriction includes prohibition.

Here, the control change means according to the first aspect of the present invention is, for example, a method of weakening the degree of reduction of the braking force of the two braking force reduction means to the same degree, or, for example, a method of weakening the degree of reduction of the braking force of one of the braking force reduction means. Is made larger than the braking force reduction degree of the other braking force reduction means is made weaker. Also,
When the rotation of one of the wheels is predicted to stop, the control change is included.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

First, a first embodiment will be described. FIG. 1 shows the configuration of the brake system used in the first embodiment.
Is shown schematically in FIG. The brake system according to the present embodiment includes an anti-lock brake device for a hydraulic brake and an electric parking brake device.

An anti-lock brake device for a hydraulic brake is an anti-lock brake electronic control device (hereinafter referred to as ABS).
The ECU 83 includes an anti-lock brake control actuator (hereinafter referred to as ABSACT) 77 and the like. The electric parking brake device includes an electric parking brake electronic control device (hereinafter referred to as EPBECU) 150 and an electric parking brake actuator (hereinafter, referred to as EPBECU).
EPBACT) 130 and the like.

FIG. 2 shows details of the anti-lock brake device of the hydraulic brake. In FIG. 2, 10 is a brake pedal, 12 is a master cylinder as a hydraulic pressure source, and 14 to 20 are wheel cylinders. When the brake pedal 10 is depressed, a hydraulic pressure corresponding to the depressing force is generated in the two hydraulic chambers of the master cylinder 12,
These are supplied to the wheel cylinders 14 to 20 of the left front wheel 22, right rear wheel 24, right front wheel 26, and left rear wheel 28, respectively. One hydraulic chamber of master cylinder 12 and wheel cylinder 1
In the middle of the liquid passages 32 and 34 that connect the
Position solenoid valves 36 and 38 (hereinafter referred to as holding valves) are provided, and the holding valves 4 are similarly provided in the middle of the liquid passages 40 and 42 connecting the other hydraulic chambers and the wheel cylinders 18 and 20.
4 and 46 are provided.

In the middle of the liquid passages 50 and 52 connecting the wheel cylinders 14 and 16 and the reservoir 48,
Position electromagnetic valves 54 and 56 (hereinafter, referred to as pressure reducing valves) are provided, and pressure reducing valves 62 and 6 are provided in the middle of liquid passages 58 and 60 connecting the wheel cylinders 18 and 20 and the reservoir 48.
4 are provided. In the middle of the liquid passages 66 and 68 connecting the reservoir 48 and the master cylinder 12, a pump 72 having a motor 70 and check valves 74 and 76 are provided. During antilock control, the reservoir 4
The hydraulic fluid in 8 is pressurized and returned to master cylinder 12.

A bypass passage 78 for bypassing the holding valves 36, 38, 44, 46 is provided, and a check valve 80 is provided in the middle of the bypass passage 78. When the brake is released, the wheel cylinders 14-20
The brake fluid inside is quickly returned to the master cylinder 12 via the bypass passage 78 and the check valve 80.

The holding valve 46 and the pressure reducing valve 64 for the left and right rear wheels 28 and 24, and the holding valve 38 and the pressure reducing valve 56 are collectively referred to as a braking force control actuator 81, and the holding valve 36 for the left and right front wheels 22 and 26, The valve 54, the holding valve 44, and the pressure reducing valve 62 are collectively referred to as a braking force control actuator 82. Since the braking force control actuators 81 and 82 are the same, the operation of the braking force control actuator 81 for the left and right rear wheels 28 and 24 will be representatively described. Braking force control actuator 81
Is always in the pressure increasing state shown in the figure, and the wheel cylinder 2
0 and 16 communicate with the hydraulic chamber of the master cylinder 12. When the holding valves 46 and 38 and the pressure reducing valves 64 and 56 are switched together by excitation of a solenoid (not shown),
The braking force control actuator 81 is depressurized, and disconnects the wheel cylinders 20 and 16 from the master cylinder 12 and communicates with the reservoir 48. When the holding valves 46 and 38 are switched and the pressure reducing valves 64 and 56 are maintained at the original positions in the drawing, the braking force control actuator 81 is in the holding state, and the wheel cylinders 20 and 16 are moved to the master cylinder 12.
From the reservoir 48 as well.

The braking force control actuators 81 and 82 are A
It is controlled based on a command from the BSECU 83. ABSE
The CU 83 includes a computer 84 for calculating the vehicle speed and the like, a hydraulic control computer 86 for antilock control and control for suppressing a rear wheel hydraulic pressure rise gradient, and the like.

The input unit of the computer 84 for calculating the vehicle speed and the like is connected to wheel speed sensors 90 to 96 for detecting the rotational speeds of the wheels 22 to 28, and the output unit is connected to a hydraulic control computer 86. I have. The ROM also stores the wheel speed of each wheel, the wheel acceleration, the minimum wheel speed of the front wheel, the minimum wheel speed of the rear wheel, the estimated vehicle speed, the vehicle deceleration, the slip rate of each wheel, etc. from the output signals of the wheel speed sensors 90 to 96. Is stored.

The input section of the hydraulic control computer 86 includes:
A brake switch 98 that outputs an ON signal when the brake pedal 10 is depressed, and a master cylinder pressure sensor 100 that detects the hydraulic pressure of the master cylinder are connected in addition to the computer 84 for calculating the vehicle speed and the like.
The output of the hydraulic control computer 86 is connected to the solenoids of the braking force control actuators 81 and 82 and the motor 70 via a drive circuit (not shown). The ROM (not shown) stores a main program, an antilock control program, and the like.

Next, the operation of the anti-lock control of the hydraulic brake performed using this device will be described. The anti-lock control of the hydraulic brake is performed on each wheel 22 to
28 are performed independently. In the anti-lock control of the hydraulic brake, the output signal of the brake switch 98 is ON and the wheels 22 to 28 are in a state where the estimated vehicle speed is equal to or higher than the set value B (for example, B = 7 to 12 km / h). This is started when the slip rate of the vehicle becomes excessive. Thereafter, the braking force control actuator 81 is controlled based on both the slip ratio and the wheel acceleration, and the hydraulic pressure of the wheel cylinder is controlled so that the slip ratio falls within an appropriate range. The motor 70 is driven while the anti-lock control of the hydraulic brake is being performed, and the hydraulic fluid contained in the reservoir 48 is pressurized and returned to the master cylinder 12.

FIG. 3 shows details of the electric parking brake device. The electric parking brake device includes left and right rear wheels 28,
Parking brake unit 12 for applying a braking force to the vehicle 24
2, 124 and the parking brake units 122, 12
4 and a cable 126 connected to the
The EPBACT 130 is provided for operating the parking brake units 122 and 124 by winding the EPBACT and an EPBECU 150 for controlling the entire apparatus.

The length of the cable 126 is fixed to a length adjusting member 127 by a bolt 128 so as to be adjustable. That is, by rotating the bolt 128, the length adjusting member 1
By adjusting the distance between 27 and the EPBACT 130, the length of the cable 126 can be adjusted.

The EPBECU 150 is configured as a microprocessor mainly including a CPU 152, and includes a ROM 154 storing a processing program, a RAM 156 temporarily storing data, and an input / output port (not shown). . The EPBECU 150 has a wheel speed sensor 9 attached to the left and right rear wheels 28, 24.
6, 92, a wheel speed signal, an ON / OFF signal from an operation switch 166 disposed on the front panel of the driver's seat to instruct operation and release of the parking brake, and a shift position sensor 171 for detecting the position of the shift lever 170. Shift position signal and accelerator pedal 1
Accelerator opening sensor 173 for detecting the amount of depression of 72
Accelerator opening signal from the brake pedal 10
A brake signal or the like from a brake switch 98 for detecting depression of the vehicle is input via an input port. Further, a drive signal or the like to EPBACT 130 is output from EPBECU 150 via an output port.
Further, the EPBECU 150 and the ABS ECU 83 are connected by a communication line and communicate various information.

Next, the operation of the electric parking brake device will be described. In the electric parking brake device configured as described above, automatic parking brake control for automatically activating and releasing the parking brake according to the state of the vehicle is performed. The automatic operation of the parking brake is performed, for example, when the shift lever 170 is at the stop position of the P position or the N position, the vehicle speed is 0 km / h, the brake pedal 74 is depressed, and an ON signal is output from the brake switch 98. It is determined that the operating condition is satisfied when the signal is output, a driving signal is output from the EPB ECU 150 to the EPBACT 130, and the EPBACT 130 is driven.

In addition to the automatic parking brake control, when the operation switch 166 of the electric parking brake is operated, the operation of the parking brake is controlled based on the operation of the operation switch 166. When the operation switch 166 is turned on while the vehicle is running, the braking force can be applied to the left and right rear wheels 28 and 24, for example, as a backup of the braking force when the servo of the hydraulic brake fails. In this case, the anti-lock control of the electric parking brake is performed so that the braking force is suddenly generated in the left and right rear wheels 28 and 24 and the wheels are not locked. This antilock control is performed, for example, as follows. Left and right rear wheels 2
Based on the signals from the wheel speed sensors 96 and 92 of 8, 24, the EPBECU 150 determines whether any of the left and right rear wheels 28 and 24 is in the locked state. If it is not in the locked state, no particular control is performed. If it is in the locked state, a signal is transmitted from the EPBECU 150 to the EPBACT 130 so as to reduce the force for winding up the cable 126. With this signal, the EPBACT 130 reduces the force of winding the cable 126, and the left and right rear wheels 28, 24
The locked state is released because the braking force acting on the vehicle is reduced.

Next, the electrical configuration of the system of this embodiment will be described in detail with reference to FIG. Abs mentioned above
The ECU 83 and the EPBECU 150 are connected by communication lines, respectively, and communicate various information.

On the input side of the ABS ECU 83, wheel speed sensors 90 to 96, a brake switch 98 and the like are connected. On the other hand, on the output side of ABS ECU 83, ABS
ACT77 and the like are connected.

On the input side of the EPBECU 150, wheel speed sensors 92 and 96, a brake switch 98, an operation switch 166, a shift position sensor 171, an accelerator opening sensor 173, and the like are connected. Also, EPB
The output side of the ECU 150 is connected to the EPBACT 130 and the like.

Next, the flow of control in this embodiment will be described with reference to the flowchart of FIG.

This flowchart is started, for example, at the same time when the ignition switch is turned on.

First, at step 200, it is determined whether or not the related device is normal. For example, the abnormality of the related device is an abnormality of the anti-lock brake device or the electric parking brake device. The abnormality of the antilock brake device or the electric parking brake device can be determined by various signals input to the ABS ECU 83 and the EPBECU 150. If the associated device is normal, step 202 is executed. If there is an abnormality in the related device, the determination in step 200 is repeated.

In step 202, it is determined whether or not the vehicle is running. Whether or not the vehicle is running can be determined by the signals of the wheel speed sensors 90 to 96 provided for each wheel. If the vehicle is running, the next step 204 is executed. If the vehicle is not running,
The process returns to step 200 again.

In step 204, the brake pedal 10
It is determined whether or not is stepped on. Whether or not the brake pedal 10 is depressed can be determined by a signal from the brake switch 98. Further, for example, the determination may be made based on a signal from the master cylinder pressure sensor 100 that detects the pressure of the master cylinder 12. If the brake pedal 10 is depressed, the next step 206 is executed. If the brake pedal 10 has not been depressed, the process proceeds to step 224 described below.

In step 206, the left and right rear wheels 28, 24
It is determined whether or not is locked. Left and right rear wheels 2
Whether the left and right wheels 8 and 24 are locked is determined by the left and right rear wheels 28 and 2.
4 can be determined by the signals of the wheel speed sensors 96 and 92. If the left and right rear wheels 28, 24 are locked, the next step 208 is executed. If the left and right rear wheels 28 and 24 are not locked, the process returns to the determination in step 204.

In step 208, it is determined whether or not the operation switch 166 of the electric parking brake is ON. This is determined by the signal of the operation switch 166. If the operation switch 166 is ON, step 21
0 is executed. If the operation switch 166 is not ON, the process proceeds to step 212 described later. When the operation switch 166 is ON, the electric parking brake is operating.

In step 210, the left and right rear wheels 28, 24
Is performed to prohibit the anti-lock control of the hydraulic brake. In this step 210, the antilock control of the hydraulic brake is prohibited. Therefore, the anti-lock control of the electric parking brake and the anti-lock control of the hydraulic brake in step 218 described later are not performed simultaneously. By prohibiting the anti-lock control of the hydraulic brakes of the left and right rear wheels 28 and 24, the braking force by the hydraulic brake becomes a force corresponding to the brake pedaling force. Therefore, the braking force is not excessively reduced, and the antilock control of the two types of brakes does not interfere. When the execution of step 210 ends, step 218 described below is executed.

In step 212, the left and right rear wheels 28, 24
The control for performing the antilock control of the hydraulic brake is performed. The electric parking brake is not activated, but the left and right rear wheels 2
Since it is determined that the locks 8 and 24 are locked, the anti-lock control of the hydraulic brake is performed. Therefore, locking of the left and right rear wheels 28, 24 can be prevented. When the execution of step 212 is completed, step 214 is executed.

In step 214, the left and right rear wheels 28, 24
It is determined whether or not the anti-lock control of the hydraulic brake has been completed. If the anti-lock control for the left and right rear wheels 28, 24 has not been completed, the process returns to step 212. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination in step 204.

In step 218, anti-lock control by the electric parking brake is performed. The anti-lock control of the hydraulic brake is not performed, but the anti-lock control by the electric parking brake is performed.
4 can be prevented. When the execution of step 218 is completed, step 220 is executed.

In step 220, the left and right rear wheels 28, 24
It is determined whether or not the anti-lock control of the electric parking brake has been completed. If the anti-lock control for the left and right rear wheels 28, 24 has not been completed, the process returns to step 218. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination in step 204.

In step 224, similarly to step 208, it is determined whether or not the operation switch 166 of the electric parking brake is ON. Operation switch 166 is set to O
In the case of N, the brake pedal is not operated, but the electric parking brake is operated. Then, step 226 is executed. If the operation switch 166 is not ON, the process returns to step 200 again.

In step 226, the left and right rear wheels 28, 24
Step 20 determines whether or not is locked.
6 is performed. When the left and right rear wheels 28 and 24 are locked, the next step 228 is executed because antilock control is required. If the left and right rear wheels 28, 24 are not locked, the process returns to the next step 224.

In step 228, the anti-lock control using the electric parking brake is performed as in step 218. By this control, the locking of the left and right rear wheels 28, 24 can be prevented. When the execution of step 228 is completed, step 230 is executed.

In step 230, the left and right rear wheels 28, 24
It is determined whether or not the anti-lock control of the electric parking brake has been completed. If the anti-lock control for the left and right rear wheels 28, 24 has not been completed, the process returns to step 228. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination of step 224.

As described above, when the brake pedal 10 is depressed while the vehicle is running and a desired braking force cannot be obtained due to a servo failure or the like, the operation switch 166 of the electric parking brake is turned on and the electric parking brake is turned on. May be activated. In this case, the left and right rear wheels 28 and 24 may be locked, but the anti-lock control of the electric parking brake is permitted and the anti-lock control of the hydraulic brake is prohibited. Therefore, the antilock control of the two types of brakes is not performed simultaneously, and the braking force is not excessively reduced, and the mutual control does not interfere with each other. It doesn't get worse. When the operation switch 166 of the electric parking brake is not turned on, the left and right rear wheels 28,
In the case where 27 is locked, anti-lock control of the hydraulic brake is performed, and locking of the rear wheels can be prevented.
Further, when the operation switch 166 of the electric parking brake is turned on without operating the brake pedal 10 and the left and right rear wheels 28 and 24 are locked, the anti-lock control of the electric parking brake is performed and the rear wheel is controlled. Lock can be prevented.

In the present embodiment, the ABS ECU 83 and the ABSACT 77 are examples of the first braking force reducing means in the claims, and the EPBECU 150 and the EPB
The ACT 130 is an example of a second braking force reducing unit in the claims. Step 210 in the flowchart in FIG. 5 is an example of the braking force changing means in the claims.

Next, a second embodiment will be described. The brake system used in the second embodiment is the same as the system used in the first embodiment. That is, FIGS.
The system shown in FIG.

Next, the control flow of this embodiment will be described with reference to the flowchart of FIG.

This flowchart starts, for example, at the same time when the ignition switch is turned on.

First, at step 300, it is determined whether or not the related device is normal. If the associated device is normal, step 302 is executed. If there is an abnormality in the related device, the determination in step 300 is repeated.

In step 302, it is determined whether or not the vehicle is running. If the vehicle is running, the next step 304 is executed. If the vehicle is not running, the process returns to step 300 again.

In step 304, it is determined whether or not the operation switch 166 of the electric parking brake is ON. If the operation switch 166 is ON, the next step 3
06 is executed. If the operation switch 166 is not ON, the determination in step 324 described below is made. In addition,
When the operation switch 166 is ON, the electric parking brake is operating.

In step 306, the left and right rear wheels 28, 24
It is determined whether or not is locked. Left and right rear wheels 2
If 8, 24 is locked, the next step 308 is performed. If the left and right rear wheels 28 and 24 are not locked, the process returns to step 304.

In step 308, the brake pedal 10
It is determined whether or not is stepped on. If the brake pedal 10 is depressed, the next step 310 is executed. If the brake pedal 10 has not been depressed, step 312 described below is executed.

In step 310, the left and right rear wheels 28, 24
Is performed to prohibit the anti-lock control of the electric parking brake. In step 310, the anti-lock control of the electric parking brake is prohibited, so that the anti-lock control of the electric parking brake and the hydraulic brake is not performed simultaneously. By prohibiting the anti-lock control of the electric parking brakes of the left and right rear wheels 28, 24, the braking force of the electric parking brake is maintained, and the braking force is not excessively reduced. Does not interfere. When the execution of step 310 ends, step 318 described below is executed.

In step 312, the left and right rear wheels 28, 24
Is performed to perform anti-lock control of the electric parking brake. Although the hydraulic brake is not operated, it is determined that the left and right rear wheels 28 and 24 are locked, so the anti-lock control of the electric parking brake is performed. Therefore, locking of the left and right rear wheels 28, 24 can be prevented. When the execution of step 312 is completed, step 31
4 is executed.

In step 314, the left and right rear wheels 28, 24
It is determined whether or not the anti-lock control of the electric parking brake has been completed. If the antilock control of the left and right rear wheels 28 and 24 has not been completed, the process returns to step 312. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination of step 304.

In step 318, anti-lock control is performed by a hydraulic brake. The anti-lock control of the electric parking brake is not performed, but the anti-lock control of the hydraulic brake is performed, so that the locking of the left and right rear wheels 28, 24 can be prevented. When the execution of step 318 ends, step 320 is executed.

At step 320, the left and right rear wheels 28, 24
It is determined whether the anti-lock control of the hydraulic brake has been completed. If the anti-lock control of the left and right rear wheels 28 and 24 has not been completed, the process returns to step 318. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination of step 304.

In step 324, it is determined whether or not the brake pedal 10 is depressed, as in step 308. When the brake pedal 10 is depressed,
The electric parking brake is not activated, but the hydraulic brake is activated. Then, step 326 is executed. If the brake pedal 10 has not been depressed, the process returns to step 300 again.

In step 326, the left and right rear wheels 28, 24
It is determined in step 30 whether or not the device is locked.
6 is performed. When the left and right rear wheels 28 and 24 are locked, anti-lock control is required, so the next step 328 is executed. If the left and right rear wheels 28, 24 are not locked, the process returns to the determination of step 324.

In step 328, antilock control of the hydraulic brake is performed as in step 318. By this control, the locking of the left and right rear wheels 28, 24 can be prevented. When the execution of step 328 is completed, step 330 is executed.

In step 330, the left and right rear wheels 28, 24
It is determined whether the anti-lock control of the hydraulic brake has been completed. If the anti-lock control for the left and right rear wheels 28, 24 has not been completed, the process returns to step 328. When the antilock control of the left and right rear wheels 28 and 24 has been completed, the process returns to the determination of step 324.

According to the above description, similarly to the first embodiment, when the brake pedal 10 is depressed while the vehicle is running and a desired braking force cannot be obtained due to a servo failure or the like, the operation switch of the electric parking brake is operated. 166 may be turned on to operate the electric parking brake. In this case, the left and right rear wheels 28 and 24 may be locked, but the antilock control of the hydraulic brake is permitted and the antilock control of the electric parking brake is prohibited. Therefore, the antilock control of the two types of brakes is not performed simultaneously, and the braking force is not excessively reduced and the controls do not interfere with each other. Further, the hydraulic brake is not actuated, and the operation switch 166 of the electric parking brake is turned on, and the left and right rear wheels 2 are turned on.
When the locks 8 and 27 are locked, the anti-lock control of the electric parking brake is performed, and the lock of the rear wheels can be prevented.

In this embodiment, the ABS ECU 83 and the ABSACT 77 are examples of the first braking force reducing means in the claims, and the EPBECU 150 and the EPB
The ACT 130 is an example of a second braking force reducing unit in the claims. Step 310 in the flowchart in FIG. 6 is an example of the braking force changing means in the claims.

In the first and second embodiments, the anti-lock control of either the electric parking brake or the hydraulic brake is prohibited, but the anti-lock control of either the electric parking brake or the hydraulic brake is prohibited. The reduction of the braking force caused by the braking force may be limited. In the above two embodiments, when the left and right rear wheels are locked, the anti-lock control of either the electric parking brake or the hydraulic brake is prohibited. If it is anticipated that anti-lock control of either the electric parking brake or the hydraulic brake will be performed, the anti-lock control may be prohibited.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention

SUMMARY OF THE INVENTION

The present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, including the embodiment described in the section of the Invention.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a brake system used in an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a configuration of an antilock brake device used in an embodiment of the present invention.

FIG. 3 is a diagram schematically showing a configuration of an electric parking brake device used in an embodiment of the present invention.

FIG. 4 is a block diagram showing an electrical configuration of a brake system used in the embodiment of the present invention.

FIG. 5 is a flowchart for performing control according to the first embodiment of the present invention.

FIG. 6 is a flowchart for controlling the second embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 brake pedal 14, 16, 18, 20 wheel cylinder 22, 24, 26, 28 wheel 77 anti-lock brake control actuator 83 anti-lock brake electronic control device 90, 92, 94, 96 wheel speed sensor 122, 124 parking brake unit 126 Cable 130 Electric parking brake actuator 150 Electric parking brake electronic control unit 166 Electric parking brake operation switch

Claims (3)

[Claims] A first braking force generating means for generating a braking force on a wheel in accordance with an operation of a brake pedal; and a driving means for applying a braking force to at least one of a pair of left and right front wheels or a rear wheel. Second braking force generation means to be added; wheel rotation speed detection means for detecting a rotation speed of the wheel; and a rotation speed of the first braking force generation means based on the rotation speed of the wheel detected by the wheel rotation speed detection means. First braking force reduction means for performing control for reducing braking force; and control for reducing the braking force of the second braking force generation means based on the rotation speed of the wheel detected by the wheel rotation speed detection means. A second braking force reducing unit that performs the control of the first braking force reducing unit when the first braking force generating unit and the second braking force generating unit operate simultaneously while the vehicle is traveling; The second braking force reduction At least one of the step controls is changed by the control changing means in a case where only one of the first braking force generating means and the second braking force generating means is operating. A brake control device characterized by the following. 2. The brake control device according to claim 1, wherein said control change means changes the control when it is determined that rotation of at least one of said wheels has stopped. 3. The brake control device according to claim 1, wherein the control changing means limits control of one of the braking force reducing means.