JP2002067909A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance cooperation between a hydraulic brake device and an electric brake device and exact utilization of these brake devices. SOLUTION: The hydraulic brake device HB is applied to right and left front wheels FR, FL, and the electric brake device EB is applied to right and left rear wheels RR, RL. When malfunction is generated in the hydraulic brake device HB, braking force of the right and left rear wheels RR, RL by the electric brake device EB is increased thereby compensating a shortage of the braking force of the right and left front wheels FR, FL, or generation of an angular moment of the vehicle due to the braking force is restrained by applying the braking force only to the wheels positioned in an diagonal relationship. Further, when the vehicle is in an extremely low speed running state or stopped state, or a parking brake is in an operating state, the operation of the electric brake device EB is stopped or restrained thereby restraining power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake device for braking a vehicle by applying a braking torque to each wheel.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No. Hei.
No. 8 and Japanese Patent Application Laid-Open No. 1-164662, hydraulic brakes driven by wheel cylinders are disposed at the front, rear, left and right wheel positions of a vehicle, respectively, in response to depression of a brake pedal. 2. Description of the Related Art A vehicle brake device that operates a hydraulic brake by brake hydraulic pressure supplied to each wheel cylinder to apply a braking force to each wheel according to the brake hydraulic pressure is well known. In recent years, for example, Japanese Patent Application Laid-Open No. H11-43041
As shown in the publication, an electric brake using an electric motor as a drive source is disposed at the front, rear, left and right wheel positions of the vehicle, and the electric brake is rotated by rotating the electric motor in response to a depression operation of a brake pedal. A vehicle brake device that is operated to apply a braking force to each wheel according to the rotation of an electric motor is well known.

[0003]

However, in the former vehicle brake device, only the hydraulic brake is provided, and if a failure occurs in the hydraulic system, the driver is required to depress the brake pedal when depressing the brake pedal. Feels strange between the amount of depression of the brake pedal and the feeling of deceleration. Even in the latter vehicle brake device, only the electric brake is provided, and if a failure occurs in the electric system, the driver feels the above-mentioned uncomfortable feeling when depressing the brake pedal. In addition, when the vehicle is stopped by the brake pedal, an unnecessary large current flows through the electric motor even though a large braking torque for braking the wheels is not required, so that electric power is consumed wastefully. In addition, heat and breakage of the electric motor were caused.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and an object of the present invention is to provide a vehicle brake device in which a hydraulic brake device and an electric brake device cooperate with each other. An object of the present invention is to provide a vehicular brake device that appropriately utilizes a pressure brake device and an electric brake device.

In order to achieve the above object, a structural feature of the present invention is applied to a wheel belonging to a first group among a plurality of wheels, and a hydraulic fluid is applied to wheels belonging to the first group in response to a brake operation. A hydraulic brake device that applies a braking force by pressure; and a wheel that belongs to a second group that is different from the first group among the plurality of wheels, and is applied to wheels that belong to the second group according to a brake operation. An electric brake device for applying a braking force by electric power is provided. In this case, for example, the braking member (friction member) is rotated together with the wheel by a hydraulic actuator such as a hydraulic cylinder in a hydraulic brake device or by an electric actuator such as an electric motor in an electric brake device. The wheel may be braked by a frictional force with the member to be braked by pressing against the member to be braked.

In the present invention configured as described above,
By mixing different brake devices of hydraulic pressure and electricity, even in the case of hydraulic system failure such as leakage of various pipes or a negative pressure of the booster, electrical sensors such as abnormalities of sensors and battery voltage drop etc. Even when the system is abnormal, the vehicle can be stopped by using the braking force of either one of the systems, that is, by applying the braking force to the wheels belonging to one of the first and second groups. The vehicle can be stopped, and the driver can obtain a feeling of deceleration corresponding to the brake operation, and the driving safety of the vehicle can be ensured well. In addition, the hydraulic and electric brake devices can brake the vehicle while compensating for each other's weak points such as a response delay of the hydraulic brake device at a low temperature or the like, so that the braking control characteristics can be improved.

In the above-mentioned vehicle brake device,
It is preferable to provide hydraulic-electric distribution control means for changing and controlling the distribution of the braking force by the hydraulic braking device and the braking force by the electric braking device according to the state of the vehicle.
Then, for example, when an abnormality occurs in the state of application of the braking force to the wheels, the hydraulic pressure-electric distribution control means determines the distribution of the braking force by the hydraulic braking device and the braking force by the electric braking device. It is better to change the value as compared to when no abnormality occurs. Specifically, if an abnormality has occurred in the hydraulic brake device, the distribution of the braking force to the wheels belonging to the second group is increased, and if an abnormality has occurred in the electric brake device, the first group is assigned. Increase the distribution of braking force to the wheels to which it belongs.

According to this, if an abnormality occurs in the application of the braking force to the wheels in one of the first and second groups, the braking force of the wheels belonging to the same group decreases, but the other group does not. As a result of the increase in the distribution of the braking force of the wheels belonging to the group, the decrease in the braking force of the wheels belonging to the one group can be compensated for by the braking force of the wheels belonging to the other group. Therefore, even in such a case, the vehicle can be stopped accurately, and the running stability of the vehicle is ensured.

Also, for example, the plurality of wheels are constituted by front wheels and rear wheels, and the wheels belonging to the first group are either one of the front wheels and rear wheels and belong to the wheels belonging to the second group. Is the other of the front wheel and the rear wheel, the hydraulic pressure-electric distribution control means requests distribution of a braking force by the hydraulic brake device and a braking force by the electric brake device in accordance with a brake operation. It may be changed according to the magnitude of the braking force to be performed. According to this, the distribution of the braking force between the front wheels and the rear wheels can be controlled so as to be close to the ideal distribution, and the locking of the wheels, particularly the locking of the rear wheels, can be avoided, and the vehicle Driving stability can be ensured. Also,
In this case, the ideal distribution of the braking force changes, for example, according to the load on the front and rear wheels of the vehicle. The allocation should be determined.

Further, when the distribution of the braking force of the wheels belonging to the first group and the braking force of the wheels belonging to the second group is controlled as described above, the braking force by the hydraulic brake device and the braking force by the electric brake device are controlled. When controlling the distribution with the braking force, the braking force of the wheels belonging to the second group, that is, the braking force by the electric brake device may be controlled. Since controlling the electric brake device electrically is simpler than controlling the hydraulic brake device electrically, the braking force of the wheels belonging to the first group and the braking force of the wheels belonging to the second group are controlled. Power and distribution can be easily controlled.

Further, in a vehicle brake device in which a hydraulic brake device is applied to wheels belonging to a first group and an electric brake device is applied to wheels belonging to a second group, the first and second groups may be provided. At least one of the groups is configured to include a left wheel and a right wheel, and controls the hydraulic brake device or the electric brake device according to the state of the vehicle,
It is preferable to provide a left-right distribution control means for controlling distribution of each braking force applied to the left wheel and the right wheel belonging to the one group. In this case, for example, when an abnormality occurs in the application state of the braking force to the wheels, the left / right distribution control unit changes the distribution of the braking force applied to the left wheel and the right wheel to an abnormal state in the application state of the braking force. It is good to change it according to the position of the wheel where the occurrence has occurred.

According to this, when an abnormality occurs in the application of the braking force to one wheel and the braking force of only one wheel is insufficient, the braking force is applied to one wheel on the same left and right side where the abnormality has occurred. Can be controlled to be greater than the braking force on one wheel on the left and right opposite sides.
As a result, the rotational moment of the vehicle due to the application of the braking force imbalanced in the left and right direction can be suppressed, and the vehicle can be stopped while the running stability of the vehicle is ensured.

[0013] In addition to the above, the left-right distribution control means may change the distribution of the braking force applied to the left wheel and the right wheel depending on the running state of the vehicle. The traveling state amount of the vehicle is, for example, a vehicle speed, a steering angle, or the like.Thus, the distribution of the braking force applied to the left wheel and the right wheel is determined depending on the traveling speed of the vehicle, the turning state, and the like. You. As a result, the vehicle can be stopped in a state in which the running stability of the vehicle is better ensured.

When the second group includes a left wheel and a right wheel, the electric brake device is constituted by a pair of electric actuators that independently apply a braking force to the left wheel and the right wheel. , The right and left distribution control means,
The same pair of electric actuators may be controlled in different modes. Also in this case, since only the electric actuator needs to be electrically controlled, the distribution of the braking force between the left wheel and the right wheel can be easily controlled.

Further, in a vehicle brake device in which a hydraulic brake device is applied to wheels belonging to a first group and an electric brake device is applied to wheels belonging to a second group, the electric brake device may be used in accordance with the state of the vehicle. It is preferable to provide stop suppression means for stopping or suppressing the operation of the brake device. In this case, for example, when the vehicle is in an extremely low speed running state or a stopped state, or when the parking brake is in an operating state, the operation of the electric brake device may be stopped or suppressed.

According to this, a large braking force is not required, but it may be necessary to apply the braking force for a long time. In the middle, since the operation of the electric brake device is stopped or suppressed, it is possible to prevent heat generation, damage, wasteful power consumption, and the like of the electric brake device due to continuous energization.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an entire vehicle brake device according to the embodiment.

The vehicular brake system comprises front left and right wheels F
It comprises a hydraulic brake device HB for applying a braking force to L and FR, and an electric brake device EB for applying a braking force to the left and right rear wheels RL and RR. Further, the vehicle brake device includes a brake pedal 11 as a brake operation member for a service brake, and a parking pedal 12 as a brake operation member for a parking brake. When the brake pedal 11 is operated, the hydraulic brake device HB and the electric brake device EB are operated, and the operation amount (or operation force) F of the pedal 11 is applied to the left and right front wheels FL, FR and the left and right rear wheels RL, RR. Is applied. The brake pedal 11 is biased to a reference position by a spring (not shown).

When the parking pedal 12 is operated, the electric brake device EB is operated, and the left and right rear wheels RL and RR are operated.
, A braking force corresponding to the operation amount (or operation force) of the pedal 12 is applied and maintained. However, the application of the braking force corresponding to the operation of the parking pedal 12 is not electrically controlled, but is performed mechanically via the parking brake cables 14a and 14b by the parking brake mechanism 13 to which the pedal 12 is assembled. It is controlled by an appropriate pulling force. A release lever 15 is also attached to the parking brake mechanism 13, and the operation of the parking pedal 12 is released by operating the lever 15,
The braking force of the left and right rear wheels RL, RR is also released.

The hydraulic brake device HB includes left and right front wheels F
Hydraulic brakes 21a and 21b for applying a braking force to L and FR are provided. These hydraulic brakes 21a, 21b are provided with friction pads, which are non-rotatably held by a mounting bracket, which is a vehicle body-side member, as a friction engagement member with a disk rotor which rotates together with the wheels by the operation of the wheel cylinders 22a, 22b. By doing so, the rotation of the wheels is suppressed. In each wheel cylinder 22a, 22b, a brake oil pressure corresponding to the operation amount (or operation force) F of the brake pedal 11 is applied to each of the liquid chambers 23a, 23 of the tandem master cylinder 23.
b. These liquid chambers 23
Reference numerals a and b respectively communicate with an oil tank 24 storing brake oil.

In this embodiment, the disc-type hydraulic brakes 21a and 21b are employed. However, the disc-type hydraulic brakes 21a and 21b can be replaced with drum-type hydraulic brakes. . Also in this case, the drum-type hydraulic brake has a built-in wheel cylinder, and applies a braking force to the left and right front wheels FL and FR by supplying brake hydraulic pressure to the wheel cylinder.

Each liquid chamber 23 of the tandem master cylinder 23
Electromagnetic valves 25a and 25b are interposed between the wheel cylinders 22a and 22b and the wheel cylinders 22a and 22b, respectively. The electromagnetic valves 25a and 25b are maintained in the illustrated communication state when not energized, respectively, and are switched to the non-communication state when energized. These electromagnetic valves 25a and 25b include:
Return check valves 26a and 26b are connected in parallel. Check valves 26a, 26b
Releases the hydraulic pressure supplied to the wheel cylinders 22a and 22b in response to the release of the depression operation of the brake pedal 11 when the electromagnetic valves 25a and 25b are in the non-communication state, respectively.

The wheel cylinders 22a and 22b have electromagnetic valves 27a and 27b and reservoirs 28a and 28b, respectively.
8b are connected in series. Electromagnetic valve 27
a, 27b are respectively kept in a non-communication state in the drawing when the power is not supplied, and the reservoirs 2a, 27b
The brake oil is prevented from flowing out to 8a and 28b, and is switched to the communication state by energization to allow the brake oil to flow out. Pumps 32a and 32b driven by the electric motor 31 are connected to the reservoirs 28a and 28b, respectively. Pumps 32a, 32b are connected to reservoirs 28a,
Pumping the brake oil in 28b, the electromagnetic valve 25
a, 25b.

Next, an electric control device of the hydraulic brake device HB will be described. This electric control device includes a hydraulic brake controller 40. The hydraulic brake controller 40 is mainly configured by a computer 41 including a CPU, a ROM, and a RAM. The computer 41 of the hydraulic brake controller 40 detects an abnormality of the hydraulic brake device HB and controls the electromagnetic valves 25a, 25b, 27a, 27b and the electric motor 31 by executing a program described later stored in the ROM. Thus, the brake hydraulic pressure supplied to the wheel cylinders 22a and 22b is controlled in accordance with the operation of the brake pedal 11 or independently of the operation of the pedal 11. On the input side of the hydraulic brake controller 40, an operation amount sensor 51,
Brake pedal switch 52, oil pressure sensors 53a, 53
b, 54a, 54b, a vehicle speed sensor 55, and wheel speed sensors 56a, 56b are connected.

The operation amount sensor 51 is connected to the brake pedal 11
The amount of depressing operation (or operating force) F is detected. In addition,
The operation amount F corresponds to the operation force applied to the brake pedal 11 because the brake pedal 11 is biased to a reference position by a spring (not shown). In addition,
The operation amount sensor 51 may be replaced with a sensor for detecting the actual operation force F applied to the brake pedal 11, or the operation amount (or operation force) F may be calculated from the oil pressure value in the tandem master cylinder 23. You may make it detect.

The brake pedal switch 52 is switched according to the operation of the brake pedal 11, and is turned off when the pedal 11 is not operated and turned on when the pedal 11 is operated. The hydraulic pressure sensors 53a and 53b detect brake hydraulic pressures (MP1 and MP2) of both the liquid chambers 23a and 23b of the tandem master cylinder 23, respectively. The oil pressure sensors 54a and 54b detect the brake oil pressure in the wheel cylinders 22a and 22b, respectively. The vehicle speed sensor 55 detects the vehicle speed V by detecting the rotation of the output shaft of the transmission. The wheel speed sensors 56a and 56b are provided on the left and right front wheels FL and FR, respectively, and the wheel speeds Vw1 and Vw of the left and right front wheels FL and FR are respectively provided.
This is to detect w2.

The electric brake device EB includes left and right rear wheels R
Electric brakes 60a, 60b including electric motors 61a, 61b to apply a braking force to L and RR, respectively.
Are provided. In the present embodiment, the electric motors 61a and 61b are DC motors, but may be ultrasonic motors. Further, in this embodiment, a drum-type electric brake 60a, 60b, which will be described in detail later, is adopted as the electric brake 60a, 60b.
A disk-type electric brake can be used in place of 60b.

Here, the electric brakes 60a and 60b used in this embodiment will be described in detail. These electric brakes 60a and 60b are of a duo servo type as shown in FIG. Electric brakes 60a, 60b
The backing plate 200 has the same configuration, and has a substantially disc-shaped backing plate 200.
, A pair of brake shoes 202a and 202b having a generally arc shape, a drum 206 having a friction surface 204 on an inner peripheral surface and rotating with wheels, and a pair of shoes 2
02a, 202b and an electric actuator 207 for expanding one end of each other. The backing plate 200 is non-rotatably attached to a vehicle-side member (not shown).

A pair of brake shoes 202a, 202b
By being engaged with anchor pins 208 fixed to the backing plate 200 at one end portions facing each other, each is rotatably held in a state where it is prevented from rotating with the drum 206. The other ends are connected by struts 210. The force acting on one shoe is transmitted to the other shoe by the strut 210. Note that the pair of brake shoes 202a, 202b can be moved along the surface of the backing plate 200 by the shoe hold-down devices 212a, 212b.

A pair of brake shoes 202a, 202b
As shown in the drawing, the other ends of the pair are biased in a direction approaching each other by a spring 214, and the one end is biased toward the anchor pin 208 by each of the shoe return springs 215a and 215b. The strut 216 and the return spring 21 are provided at one end.
8 is also provided.

Brake linings 219a and 219b as friction engagement members are held on the outer peripheral surface of each of the brake shoes 202a and 202b, and the pair of brake linings 219a and 219b are connected to the drum 206.
The frictional force is generated between the brake linings 219 a and 219 b and the drum 206 by frictionally engaging the inner peripheral surface 204 of the drum 206. In the present embodiment, the strut 210 is provided with an adjusting mechanism, and the brake linings 219a and 219b and the drum inner peripheral surface 20 are changed according to wear of the brake linings 219a and 219b.
Adjust the gap with 4.

Each of the brake shoes 202a and 202b is
Rim 224a, 224b and web 222a, 2 respectively
22b, and one end of a lever 230a, 230b is attached to a pin 232 on the web 222a, 222b, respectively.
a, 232b so as to be rotatable. Opposite portions of the levers 230a, 230b and the webs 222a, 222b are provided with cutouts, respectively, and the struts 216 are provided with the cutouts 216 at both ends thereof.
Is provided in a state of being engaged with.

The other end of the lever 230a has an electric actuator 207 including the electric motor 61a (or 61b).
And one end of a parking brake cable 14a (or 14b) is connected to the other end of the lever 230b. Brake pedal 11 for service brake
Is operated, the lever 230a is rotated by driving the electric motor 61a or 61b (electric actuator 207), and the strut 216 causes the pair of brake shoes 202a and 202b to expand. Also,
When the parking pedal 12 is operated, the lever 230b
Is rotated, and the pair of brake shoes 202a and 202b are expanded by the strut 216. The other end of the lever 230b and the backing plate 20
The return spring 244 is disposed coaxially with the parking brake cable 14a (or 14b).

The electric actuator 207 includes a speed reducer and a motion conversion mechanism in addition to the electric motor 61a (or 61b). The rotation of the output shaft of the electric motor 61a (or 61b) is reduced by the speed reducer, and the rotational motion is converted to linear motion by the ball screw mechanism.
The other end of the lever 230a is connected to the output member of the ball screw mechanism.

The parking brake cable 14a (or 14b) is connected to the parking brake mechanism 13 at the other end as described above, and applies a pulling force corresponding to the operation force (operation amount) of the parking pedal 12. Is done. By this pulling force, the pair of brake shoes 20
The lever 230b is rotated in a direction in which the 2a and 202b expand.

Next, an electric control device of the electric brake device EB will be described. This electric control device includes an electric brake controller 70. The electric brake controller 70 is also configured mainly by a computer 71 including a CPU, a ROM, and a RAM. The computer 71 of the electric brake controller 70 detects the abnormality of the electric brake device EB and controls the electric motors 61a and 61b to brake the left and right rear wheels RL and RR by executing a program described later stored in the ROM. Braking control is performed according to the operation of the pedal 11. The electric brake controller 70 is connected to the hydraulic brake controller 40 to transmit and receive signals, and has a parking brake switch 81, braking torque sensors 82a and 82b, wheel speed sensors 83a and 83 on its input side.
b, motor current sensors 84a, 84b, steering angle sensor 85
And a shift position sensor 86. The operation amount sensor 51, the brake pedal switch 52, and the vehicle speed sensor 55 are also connected to the electric brake controller 70.

The parking brake switch 81 is constituted by a changeover switch mounted on the parking brake mechanism, and is normally kept in an off state. State. The braking torque sensors 82a and 82b are constituted by distortion sensors attached to the anchor pins 208 of the electric brakes 60a and 60b, and detect the braking torque generated by the electric brakes 60a and 60b based on the distortion of the anchor pins 208. When an electric disc brake is used instead of the drum type electric brakes 60a and 60b, the braking torque sensors 82a and 82b are constituted by strain sensors attached to a mounting bracket.

The wheel speed sensors 83a and 83b are provided on the left and right rear wheels RL and RR, respectively, and detect the wheel speeds Vw3 and Vw4 of the left and right rear wheels RL and RR. The motor current sensors 84a and 84b are incorporated in the drive circuit 62, and the electric motor 61 of the electric brakes 60a and 60b
The actual current I flowing through the coils a and 61b is detected. The steering angle sensor 85 is mounted on the handle shaft, and detects the rotation angle of the handle to set the front left and right wheels FL, FR.
Is detected. However, the steering angle θf represents “0” at the neutral position of the left and right front wheels FL and FR, rightward steering is represented by positive, and leftward steering is represented by negative. The shift position sensor 86 is mounted on the transmission to detect the position of the shift lever (particularly, the parking position).

On the other hand, the output side of the electric brake controller 70 is connected to the drive circuit 62. The drive circuit 62 receives an electric motor 61 from the battery 63 in response to a command signal from the electric brake controller 70.
a, 61b. In the present embodiment,
A command signal indicating a duty ratio is output from the electric brake controller 70 to the drive circuit 62, and a current according to the duty ratio is supplied to the electric motors 61a and 61b.

Although the detailed description is omitted in this specification, as shown by the broken line in FIG.
The position sensors 89a and 89b may be provided in the positions a and 60b. These position sensors 89a and 89b are
For example, by measuring the rotation angles of the electric motors 61a and 61b, the relative positions of the brake shoes 202a and 202b with respect to the drum 206 are detected and output. These position sensors 89a and 89b are used to control the electric motors 61a and 61b until the brake linings 219a and 219b contact the inner peripheral surface 204 of the drum 206.
Is rotated at a high speed to improve the response of the generation of the braking torque, to improve the control accuracy of the application of the braking force to the left and right rear wheels RL and RR, and to use the braking torque sensor 82.
The sensor is used as a substitute for the sensor used in the braking force application control such as a and 82b when the sensor is abnormal.

Hereinafter, the operation of the vehicle brake device configured as described above will be described. First, the hydraulic brake device H
The case where B and the electric brake device EB are also normal will be described. In the hydraulic brake device HB, the electromagnetic valves 25a, 25b, 27a, 27b are kept in the illustrated state by de-energization, and if the brake pedal 11 is not depressed, the wheel cylinders 22a, 22b are turned off.
b is not supplied with the brake oil pressure and the hydraulic brake 21
No braking force is applied to the left and right front wheels FL, FR by the a, 21b. When the brake pedal 11 is depressed,
The tandem master cylinder 23 supplies a brake hydraulic pressure according to the depression operation amount (or operation force) F of the pedal 11 to the wheel cylinders 22a and 22b. Therefore,
The hydraulic brakes 21a and 21b apply a braking force according to the operation amount (or operation force) F of the brake pedal 11 to the left and right front wheels F
L, FR. In this case as well, the hydraulic brake controller 40 executes a program (not shown) to detect the abnormality of the hydraulic brake device HB.

On the other hand, in the electric brake device EB, the electric brake controller 70 repeatedly executes the rear wheel braking program of FIG. 3 every predetermined short time.
The execution of this program is started in step S10, and in step S12, the brake pedal switch 52
It is determined whether or not the brake pedal 11 is depressed on the basis of the signal from. If the brake pedal 11 has not been depressed, "NO" is determined in the step S12, and the current "0" is determined in the step S14.
A command signal indicating (current off) is output to the drive circuit 62. Therefore, in this case, since the drive circuit 62 does not supply current to the electric motors 61a and 61b, the braking force by the electric brakes 60a and 60b is not applied to the left and right rear wheels RL and RL.
Not assigned to RR.

When the brake pedal 11 is depressed, "YES" is determined in step S12.
The program proceeds to step S16. Step S
In step 16, as described in detail later, it is determined whether or not the hydraulic brake device HB is abnormal based on a signal from the hydraulic brake controller 40. Now, since the hydraulic brake device HB is normal, step S1
It is determined "NO" in 6 and it is determined in step S18 whether the operation suppression condition of the electric brake device EB is satisfied. These operation suppression conditions determine whether or not the vehicle is stopped, the vehicle is traveling at extremely low speed such as during a traffic jam, and the parking brake is operating, based on the following determination conditions (1) to (5).

(1) The vehicle speed V detected by the vehicle speed sensor 55 is substantially "0" indicating the stopped state of the vehicle.
It should be noted that the vehicle speed V is determined by the wheel speed sensors 56a, 56b, 8
3a, 83b, the wheel speeds Vw1, Vw2,
The calculation may be performed using Vw3 and Vw4. Also,
To the condition (V = 0), that the depressing time of the brake pedal 11 is longer than a predetermined time may be added as an AND condition. The depressing time of the brake pedal 11 is detected by measuring the time during which the brake pedal switch 52 is kept on by a timer provided in the computer 71 or the like.

(2) The vehicle speed V detected by the vehicle speed sensor 55 is equal to or less than Vo indicating the extremely low speed state of the vehicle.
Also in this case, the vehicle speed V is determined by the wheel speed sensor 56.
The calculation may be performed using the wheel speeds Vw1, Vw2, Vw3, Vw4 detected by a, 56b, 83a, 83b.

(3) The operation amount (or operation force) F of the brake pedal 11 detected by the operation amount sensor 51 is equal to or smaller than a small predetermined value Fo. In addition, the condition (F ≦ F
In (o), the condition (2) (V ≦ Vo) may be added as an AND condition.

(4) The parking pedal 12 is depressed, and the parking brake switch 81 is on.

(5) The shift lever detected by the shift position sensor 86 is at the parking position. Further, the condition (4) (the parking brake switch 81 is in the ON state) may be added to this condition as an AND condition.

If none of the above conditions (1) to (5) is satisfied, "NO" is determined in step S18, that is, it is determined that the operation suppression condition is not satisfied.
At step 20, the normal control processing of the electric brake is executed, and at step S26, the execution of the rear wheel braking program is temporarily ended.

In the normal control processing of the electric brake in step S20, a target braking torque T * corresponding to the operation amount (or operation force) F of the brake pedal 11 detected by the operation amount sensor 51 is calculated, and the same calculation is performed. The current flowing through the electric motors 61a and 61b is controlled such that the actual braking torque T detected by the braking torque sensors 82a and 82b matches the target braking torque T * thus set. In this case, a command signal indicating a duty ratio for flowing the current to the electric motors 61a and 61b is supplied to the drive circuit 62, and the drive circuit 62 flows the current from the battery 63 to the electric motors 61a and 61b according to the command signal. .

The electric motors 61a and 61b rotate the lever 230a with a driving force corresponding to the supply current. A pair of shoes 202a, 202b is formed by the strut 216.
Is expanded, and the friction engagement member (the brake lining 2
19a, 219b) is pressed against the inner peripheral surface 204 of the drum 206. The friction engagement member is frictionally engaged with the drum inner peripheral surface 204, and a frictional force is generated therebetween. Therefore, rotation of the wheel is suppressed, and braking torque is applied to the wheel.

The swinging force based on the frictional force generated in one shoe 202b and the electric actuator 207
Is transmitted from the other end to the other end of the other shoe 202a via the strut 210. The other shoe 202a is pressed against the drum inner peripheral surface 204 by the sum of the twisting force and the expanding force, and the other shoe 202a is pressed.
A friction force greater than 02b occurs. As a result, the left and right rear wheels RL, RR are driven by the electric brakes 60a, 60b.
A braking torque equal to the target braking torque T * corresponding to the operation amount (or operation force) F of the brake pedal 11 is applied. Thus, the output of one shoe 202b becomes the input of the other shoe 202a, and a double servo effect is obtained, so that a large braking torque can be obtained in a duo servo type drum brake.

The application of the braking torque to the left and right rear wheels RL, RR by the electric brake controller 70 will be described in detail with reference to the functional block diagram of FIG. In block B1, the target braking torque T * is determined based on the operation amount (or operation force) F of the brake pedal 11 by the driver. In blocks B2 and B3,
A target current value I * is obtained according to the relationship between the target braking torque T * and the target current value I *, and a duty ratio is obtained according to the relationship between the target current value I * and the duty ratio. The signal is output to drive circuit 62. on the other hand,
Left and right rear wheels RL, R by electric brakes 60a, 60b
When a braking torque is applied to R, the braking torque is detected by the braking torque sensors 82a and 82b, and the detected actual braking torque T is fed back. Then, a control signal corresponding to the difference between the target braking torque T * and the actual braking torque T is added to the signal indicating the duty ratio, and a command signal indicating the result of the addition is output to the drive circuit 62. .

As a result, the current flowing through the electric motors 61a and 61b is feedback-controlled so that the deviation between the target braking torque T * and the actual braking torque T is eliminated, and the electric brakes 60a and 60b are moved right and left. Wheel RL,
RR is braked with a braking torque equal to the target braking torque T *. In the feedback control of the braking torque, the braking torque may be determined based on the actual difference, may be determined based on the differential value of the difference, or may be determined based on the integral value. Alternatively, it may be determined based on two or more of the actual difference, the differential value, and the integral value. Further, the aforementioned target braking torque T *
Table showing the relationship between the target current value I * and the duty ratio (when the friction coefficient is set to the basic value μo), the table showing the relationship between the target current value I * and the duty ratio, and the brake operation force F and the target braking torque T *. The table expressing the relationship of
Each value is stored in the ROM provided in 1 and is determined using each table. However, each value can be determined by calculation.

In the normal control process of the electric brake in step S20, the current I flowing through the electric motors 61a and 61b can be controlled by feedback instead of the torque feedback control. This current feedback control will be described with reference to a control function block diagram in the same manner as described above. FIG. 5 shows the control function block diagram. First, as shown in block B11, based on the brake operation force F, the target brake operation force D
* Is determined. The brake operating force is determined by the electric motors 61a, 61b and the electric brakes 60a, 60b.
0b, specifically the electric motor 61a,
This is the force exerted on lever 230a by 61b. Next, as shown in blocks B12 and B13, the target current value I * is determined based on the relationship between the target brake operating force D * and the target current value I *, and the relationship between the target current value I * and the duty ratio is determined. The duty ratio is determined based on
In this case, the motor current sensors 84a, 84
b, the actual motor current I detected is fed back, and a feedback control amount corresponding to the difference I * -I between the determined target current value I * and the actual motor current value I is added to the determined duty ratio. Is output to the drive circuit 62 as a command signal.

As a result, the drive circuit 62 is controlled by the command signal to
A current equal to the target current value I * is supplied to a and 61b. Therefore, the electric brakes 60a and 60b generate a target brake actuation force D * corresponding to the operation amount (or operation force) F of the brake pedal 11. A table representing the relationship between the target brake actuation force D * and the target current value I *, a table representing the relationship between the target current value I * and the duty ratio,
A table or the like representing the relationship between the brake operation amount (or operation force) F and the target brake operation force D * is stored in the ROM in advance. Even with such control, the electric brake 60
a and 60b can be controlled, but this control is not necessarily as accurate as the above-described control in that the actual braking torque T is not used as compared with the above-described torque feedback control. This is suitable for use when the detection accuracy of the braking torque T is not good.

In the current control, the current I actually flowing through the electric motors 61a and 61b is fed back. This current feedback may be omitted if this can be generated. In this case, the electric motors 61a, 61 in FIG.
A path for feeding back the current I of 1b may be omitted, and the command signal indicating the duty ratio determined in the block B13 may be directly supplied to the drive circuit 62.

On the other hand, if any of the conditions (1) to (5) is satisfied, "YES" is determined in step S18.
That is, it is determined that the operation suppression condition is satisfied, the electric brake prohibition (suppression) process is executed in step S22, and the execution of the rear wheel braking program is temporarily ended in step S26.

In step S22, the electric motor 6
1a and 61b are turned off, that is, the electric motor 6 is turned off.
A current is prevented from flowing through 1a and 61b. Therefore, in this case, the electric brakes 60a and 60b cause the right and left rear wheels R to be driven by the driving force of the electric motors 61a and 61b.
L and RR are not braked. However, when the parking pedal 12 is depressed and a pulling force is applied to the parking brake cables 14a and 14b, the cables 14a and 14b are moved in a direction in which the pair of brake shoes 202a and 202b expands. , The braking force due to the depressing operation of the parking pedal 12 is applied to the left and right rear wheels RL, RR. Also in this state, the braking force of the hydraulic brakes 21a and 21b is applied to the left and right front wheels FL and FR, and the parking pedal 12 is also applied to the left and right rear wheels RL and RR while the parking brake is operating. Of the electric brakes 60a and 60b.

As described above, a vehicle that does not require a large braking force but may need to apply a long-time braking force is stopped, the vehicle is traveling at extremely low speed during traffic jams, or the parking brake is operating. , The electric motor 61a,
Since current is prevented from flowing through 61b, it is possible to prevent heat generation of the electric motors 61a and 61b due to continuous energization, damage to coils, wasteful power consumption, and the like.

In the electric brake prohibition (suppression) processing in step S22, the electric motors 61a, 61
b, no current is allowed to flow.
A current that is at least smaller than the current value obtained by the normal control process of the 20 electric brakes may flow. In this case, a predetermined small current is supplied to the electric motors 61a and 61a.
1b. Also, brake pedal 1
1 is being operated, step S2
Calculate a target braking torque smaller by a predetermined amount than the target braking torque F * determined at 0 or a target braking torque obtained by multiplying the target braking torque F * by a predetermined ratio smaller than a predetermined “1”. Then, the current flowing through the electric motors 61a, 61b may be controlled so as to achieve the calculated target braking torque, and the current flowing through the motors 61a, 61b may be limited. In the case where control is performed so that the target current I * flows through the electric motors 61a and 61b in the step S20 (in the case of FIG. 5), the target current value I * is obtained in the same manner as the case of the target braking torque F *. May be set smaller than that in step S20 to limit the current flowing through the electric motors 61a and 61b to a small current value.

As a result, even when the vehicle is stopped, the vehicle is running at extremely low speed such as in a traffic jam, or the parking brake is being operated, the electric motor 6 is continuously energized.
Heat generation of 1a, 61b, breakage of the coil, wasteful power consumption, and the like can be prevented. In particular, (2) in the above conditions (1) to (5)
When the condition V ≦ Vo or the condition F ≦ Fo of (3) is satisfied, the electric brake is performed by suppressing the current flowing through the electric motors 61a and 61b to a smaller value than by preventing the current from flowing through the electric motors 61a and 61b. It is effective to limit the braking force by 60a, 60b to a small value.

Next, a case where an abnormality has occurred in the hydraulic brake device HB or the electric brake device EB will be described. Computer 41 of hydraulic brake controller 40
The hydraulic sensor 5
3a, 53b to the brake oil pressure and oil pressure sensor 54 in each of the liquid chambers 23a, 23b of the tandem master cylinder 23.
The brake hydraulic pressures in the wheel cylinders 22a and 22b are input from a and 54b, and an abnormality of the hydraulic brake device HB such as a hydraulic pressure failure is determined according to each brake hydraulic pressure.

In the determination of this abnormality, the operation amount (steering force) F of the brake pedal 11 is input from the operation amount sensor 51, and a signal indicating the presence or absence of the operation of the brake pedal 11 is input from the brake pedal switch 52. The determination is made based on whether or not the input brake hydraulic pressure indicates a value corresponding to the operation of the brake pedal 11. For example, when the brake pedal switch 52 is
The operation of the hydraulic pressure sensor 53
If the brake oil pressure from the a and 54a indicates the atmospheric pressure, it is determined that an abnormality has occurred in the brake system of the left front wheel FL, and if the brake oil pressure from the oil pressure sensors 53b and 54b indicates the atmospheric pressure. It is determined that an abnormality has occurred in the brake system of the right front wheel FR. Also, the hydraulic pressure sensor 53
If the brake hydraulic pressure from the a and 54a is smaller than the hydraulic pressure equivalent to the operation amount (or operation force) F from the operation amount sensor 51, it is determined that an abnormality has occurred in the brake system of the left front wheel FL, and the hydraulic pressure is determined. The brake hydraulic pressure from the sensors 53b and 54b is equal to the operation amount (or operation force) F from the operation amount sensor 51.
If the hydraulic pressure is smaller than the hydraulic pressure equivalent to, it is determined that an abnormality has occurred in the brake system of the right front wheel FR. When these abnormalities are detected, the hydraulic brake controller 40
From the computer 41 to the electric brake controller 70
A signal indicating the abnormality is output to the computer 71.

During the execution of the rear wheel braking program shown in FIG. 3, the computer 71 of the electric brake controller 70
At step S16, "YES", that is, it is determined that an abnormality has occurred in the hydraulic brake system, the hydraulic system abnormality routine of step S24 is executed, and the execution of the rear wheel braking program is temporarily terminated at step S26. I do.

This hydraulic system abnormality routine is shown in detail in FIG. 6, and its execution is started in step S30, and the target braking torque T * is calculated in step S32. The method of calculating the target braking torque T * is determined in accordance with the operation amount (or operation force) F as in the case of the normal control processing of the electric brake in step S20 (see block B1 in FIG. 4). Next, in step S34, the steering angle θf detected by the steering angle sensor 85 is input, and
By determining whether the absolute value | θf | of the steering angle θf is equal to or smaller than a small predetermined value θf0, it is determined whether the vehicle is in a straight running state.

If the vehicle is substantially in a straight running state and the absolute value | θf | of the steering angle θf is equal to or smaller than the small predetermined value θf0, it is determined “YES” in step S34, and the target braking calculated in step S36 is determined. A positive predetermined value α is added to the torque T *, and each target braking torque _TL * of the left and right rear wheels RL and RR is added.
(= T * + α), calculates _{T R * (= T * +} α) , respectively. Then, in step S48, step S2
As with the normal control process for the electric braking of 0, the electric brake 60a, the left and right rear wheels RL by 60b, the braking torque applied to RR target braking torque _{T L} *, _{T R} *
The current flowing through the electric motors 61a and 61b is controlled so as to be equal to (see blocks B2 and B3 in FIG. 4).
As a result, the left and right rear wheels RL and RR are provided with the step S
A braking torque larger by a predetermined value α is applied than in the case of the normal control processing of the 20 electric brakes.

On the other hand, when the vehicle is in a turning state and the steering angle θf
Is larger than the predetermined value θf0,
In step S34, "NO" is determined, and the program proceeds to steps S38 and S40. Step S38, S4
In the case of 0, it is determined which of the brake systems of the left and right front wheels FL and FR has an abnormality based on a signal indicating the abnormality from the computer 41 of the hydraulic brake controller 40.

If an abnormality occurs only in the brake system of the left front wheel FL, "YES" is determined in the step S38, and in the step S42, the calculated target braking torque T is calculated.
A positive predetermined value α is added to * to calculate a target braking torque _TL * (= T * + α) for the left rear wheel RL, and a positive predetermined value β is subtracted from the target braking torque T * to obtain a right braking torque _TL *. the rear wheels RR of the target braking torque _{T R * (= T * -β} ) is calculated. Then, at step S48, the similar to the above, the electric brake 60a, left and rear-right wheels RL, braking torque applied to RR said target braking torque _{T L} * by 60b, to be equal to _{T R} *, the electric motor The current flowing through 61a and 61b is controlled. Thereby, a braking torque larger by the predetermined value α is applied to the left rear wheel RL than in the case of the normal control processing of the electric brake in step S20, and
A braking torque smaller by a predetermined value β is applied to the right rear wheel RR than in the normal control processing of the electric brake in step S20.

The vehicle is in a turning state and the right front wheel FR
If an abnormality occurs only in the brake system of
It is determined as "YES" in S40, and in step S44
A positive predetermined value β is subtracted from the target braking torque T * to
Target braking torque T for rear wheel RL _L* (= T * -β) is calculated
And a positive predetermined value α is applied to the target braking torque T *.
Add the target braking torque T for the right rear wheel RR._R* (= T * +
α) is calculated. Then, in step S48,
Similarly, the left and right rear wheels are driven by the electric brakes 60a and 60b.
The braking torque applied to RL and RR is equal to the target braking torque.
K T_L*, T_R* So that the electric motor 61
a, 61b. With this,
Conversely, the left rear wheel RL is
It is smaller by a predetermined value β than in the normal brake control process.
Small braking torque is applied to the right rear wheel RR.
Is a normal control process of the electric brake in step S20.
Braking torque greater by the predetermined value α than in the case of
It is.

Further, if the vehicle is in a turning state and abnormality has occurred in both brake systems of the right and right front wheels FL and FR,
In steps S38 and S40, both are determined to be "NO"
In step S46, the rear left and right wheels RL, each target braking torque _{T L} of the RR *, _{T R} * Setting each target braking torque T * calculated by the processing in step S32. Then, by the processing in step S48, the electric brake 60
a, left and right rear wheels RL by 60b, the braking torque applied to RR, the step S20 in the same target braking torque in the case of the normal control process T of the electric brake _L *, is controlled to be T R _*.

FIG. 7 shows the braking force control of the left and right rear wheels RL, RR by the hydraulic system abnormality routine. In FIG. 7, a circle indicates a normal brake system,
The crosses indicate abnormal brake systems. An upward arrow indicates an increase in the braking force, a downward arrow indicates a decrease in the braking force, and a horizontal arrow indicates no increase or decrease in the braking force.
As will be understood from now on, when an abnormality occurs in a part of the hydraulic brake device HB in a state where the vehicle is in a substantially straight traveling state, both braking forces of the left and right rear wheels RL, RR by the electric brakes 60a, 60b are reduced. The control is greatly controlled as compared with the case where both the brake systems of both the left and right front wheels FL and FR are normal. Due to such a change in the braking force distribution ratio of the left and right rear wheels RL and RR to the left and right front wheels FL and FR, the lack of the braking force of the hydraulic brake device HB for the left and right front wheels FL and FR may be reduced. The vehicle is braked well, supplemented by an electric brake device EB for the vehicle.

During the turning of the vehicle, the left and right front wheels FL, F
If an abnormality occurs in only one of the brake systems R, the left rear wheel R on the same side as the front wheel on which the abnormality has occurred is located on the left and right sides.
L (or the right rear wheel RR) by the electric brake 60a (or the electric brake 60b) exerts a braking force on the left and right front wheels F
The control is greatly controlled as compared with the case where both the L and FR brake systems are normal. At the same time, the right rear wheel RR (or the left rear wheel RL) is located diagonally to the wheel where the abnormality has occurred.
Brake 60b (or the electric brake 60
The braking force according to a) is controlled to be smaller than when both the brake systems of the left and right front wheels FL and FR are normal. By such a change in the distribution of the braking force between the left and right rear wheels RL and RR, the generation of a rotational moment about the vertical axis acting on the vehicle body due to the application of the braking force to the wheels is suppressed, and the running stability can be secured. Depending on how the predetermined values α and β are applied, the braking force on the left and right rear wheels RL and RR is controlled to increase, and the lack of braking force of the hydraulic brake device HB for the left and right front wheels FL and FR is caused by the lack of the braking force on the left and right rear wheels. Supplemented by an electric brake device EB for RL, RR, the vehicle is braked well. During turning of the vehicle, the left and right front wheels FL, F
The reason why the braking force of the left and right rear wheels RL and RR is not increased when an abnormality occurs in both the brake systems of R is to avoid spinning of the vehicle.

Next, a description will be given of a modification in which the hydraulic system abnormality routine of FIG. 6 is modified as shown in FIG. Also in this case, after the execution of step S60 is started, the target braking torque T * is calculated in step S62 as in the case of FIG. However, in this case, left and rear-right wheels RL, each target braking torque T _L of the RR *, keep temporarily set to the target braking torque T * that the T R _* and the calculated. Next, steps S64, S
At 66, it is determined which of the left and right front wheels FL and FR has an abnormality based on a signal indicating an abnormality from the computer 41 of the hydraulic brake controller 40.

If an abnormality occurs only in the brake system of the left front wheel FL, "YES" is determined in the step S64, and in a step S68, the vehicle speed V and the steering angle are obtained from the vehicle speed sensor 55 and the steering angle sensor 85. By inputting θf and referring to the table A stored in the ROM, the vehicle speed V
Then, it is determined whether or not the current running state of the vehicle determined by the steering angle θf is in the braking force application prohibition region for the right rear wheel RR. As shown in FIG. 9A, the table A stores the vehicle speed V and the steering angle θ.
f, which defines a region where the braking force is applied to the right rear wheel RR and a region where the application of the braking force is prohibited (the hatched region in FIG. 9A) when the braking system of the left front wheel FL is abnormal. Data is stored. In this case, the steering angle θf
Is less than a positive small predetermined value, that is, if the vehicle is substantially straight ahead or turning left, the vehicle speed V is equal to or higher than the predetermined vehicle speed, that is, the vehicle is in a high-speed running state, and the vehicle is in a prohibited area. If the vehicle is in a turning state, even if the vehicle speed V decreases as the steering angle θf increases, it is regarded as a prohibited area.

Then, in step S68, "YE
If S "that is, the running state of the vehicle is determined to be in the prohibited area, changes the target braking torque T _{R *} of the right rear wheel RR at step S70 to" 0 ". Step S6
When the running state of "NO" or the vehicle is determined not to forbidden region at 8, of the right rear wheel RR target braking torque T _R *
Is kept at the value set in step S62, the program proceeds to step S72.

In step S72, by referring to the table C stored in the ROM, the current running state of the vehicle determined by the vehicle speed V and the steering angle θf is changed to the left rear wheel R.
It is determined whether the braking force is in the braking force increase allowable region of L. As shown in FIG. 9C, the table C stores the vehicle speed V and the steering angle θf.
When there is an abnormality in the brake system of the left front wheel FL or the right front wheel FR, the rear wheels on the same side as the left and right front wheels (except for the left and right front wheels FL and FR when the abnormality occurs). (Both regions) in which the braking force to be applied is increased (the hatched region in FIG. 9C).
And data defining an area in which an increase in the braking force is prohibited. In this case, the absolute value of the steering angle θf | θf |
Is increased, that is, as the turning radius of the vehicle decreases, the increase in the braking force is prohibited even when the vehicle speed decreases. In other words, as the turning radius of the vehicle increases and the vehicle approaches straight running, an increase in the braking force is allowed even if the vehicle speed V increases.

Then, in step S72, "YE
If S "that is, the running state of the vehicle is determined to be in the increase-allowed area, a predetermined positive value α only greater than the target brake torque T _{L *} of the left rear wheel RL same torque T _{L *} at step S74 Change to T _L * + α. Step S7
If it is determined in step 2 that “NO”, that is, that the running state of the vehicle is not in the increase allowable region, the target braking torque T
_The program proceeds to step S88 while keeping _L * at the value set in step S62. Step S
At 88, the left and right rear wheels R are driven by the electric brakes 60a and 60b as in the case of step S48 in FIG.
L, and the braking torque applied to RR is, the set target braking torque T _L *, is controlled to be equal to T R _*.

On the other hand, if an abnormality occurs only in the brake system of the right front wheel FR, "YES" is determined in the step S66, and in a step S76, the vehicle speed V and the vehicle speed V from the vehicle speed sensor 55 and the steering angle sensor 85 are determined. Input the steering angle θf and
By referring to the table B stored in M, it is determined whether the current running state of the vehicle determined by the vehicle speed V and the steering angle θf is in the braking force application prohibition region for the left rear wheel RL.
As shown in FIG. 9 (B), the table B is determined by the vehicle speed V and the steering angle θf, and when the brake system of the right front wheel FR is abnormal, a region for applying a braking force to the left rear wheel RL, and the braking force And data that defines an area (hatched area in FIG. 9 (B)) in which the addition of a character is prohibited. In this case, if the steering angle θf is larger than the negative predetermined value having a small absolute value, that is, if the vehicle is substantially in a straight running or right turning state, the vehicle speed V is equal to or higher than the predetermined vehicle speed, that is, the vehicle is in a prohibited area when the vehicle is running at high speed. If the steering angle θf is equal to or smaller than the predetermined value, that is, if the vehicle is turning left, the prohibited area is set even if the vehicle speed V decreases as the steering angle θf decreases (the absolute value | θf | of the steering angle θf increases). .

Then, in step S76, "YE
S ", that is, when it is determined that the running state of the vehicle is in the prohibited area, the target braking torque _TL * of the left rear wheel RL is changed to" 0 "in step S78. Step S7
If “NO” in step 6, that is, if it is determined that the running state of the vehicle is not in the prohibited area, the target braking torque _TL * of the left rear wheel RL * is determined.
Is kept at the value set in step S62, the program proceeds to step S80.

In step S80, by referring to the table C stored in the ROM, the current running state of the vehicle determined by the vehicle speed V and the steering angle θf is in the braking force increase allowable region of the left rear wheel RL. Is determined. When the running state of "YES" or vehicle at the step S80 is determined to be in the increase-allowed area, than the target brake torque T _{R *} the same torque T _{R *} of the right rear wheel RR at step S82 positive by a predetermined value alpha is changed to a larger value T _R * + α. Further, when the running state of "NO" or the vehicle is determined not to increase the allowable area in the step S80, keeping the value of the target braking torque T _{R *} set in the step S62 of the right rear wheel RR Then, the program proceeds to step S88. Then, the processing of step S88, the electric brake 60a, the left and right rear wheels RL by 60b, each braking torque applied to RR is, the set target braking torque _{T L} *, is controlled to be equal to _{T R} * .

If an abnormality has occurred in both brake systems of the left front wheel FL and the right front wheel FR, steps S64 and S6.
6 are determined to be “NO”, and in step S84,
By inputting the vehicle speed V and the steering angle θf from the vehicle speed sensor 55 and the steering angle sensor 85 and referring to the aforementioned table C provided in the ROM, the current running state of the vehicle determined by the vehicle speed V and the steering angle θf can be changed. It is determined whether or not the rear wheels RL and RR are in the braking force increase allowable region. When the "YES" or running state of the vehicle is determined to be in increased tolerance range at the step S84, the left and right rear wheels RL in step S86, the target braking torque T _L * of RR, the T R _* same torque _{T L} *, _{T R} * positive only large respective predetermined value gamma than the value _{T L} * + γ, is changed to _{T R} * + γ. Further, when the running state of "NO" or the vehicle is determined not to increase the allowable area in the step S84, the left and rear-right wheels RL, the target braking torque T _L * of RR, the T R _* in the step S62 While keeping the set value, execute the program in step S
Proceed to 88. Then, by the processing in step S88,
Left and right rear wheels RL, R by electric brakes 60a, 60b
Each braking torque applied to _R is controlled so as to be equal to the set target braking torques _TL * and TR *.

Therefore, according to this modification, the vehicle speed V
Is not so large and the absolute value | θf | of the steering angle θf is not so large, if an abnormality occurs in one or both of the left and right front wheels FL and FR, the abnormal front wheel When both the left and right front wheels FL and FR are abnormal, the braking force of the left and right front wheels FL and FR is reduced by the braking force of the left and right front wheels FL and FR. The control is largely performed as compared with the case where both are normal. Due to such a change in the braking force distribution ratio of the left and right rear wheels RL and RR to the left and right front wheels FL and FR, the shortage of the braking force by the hydraulic brake device HB for the left and right front wheels FL and FR is caused by the left and right rear wheels RL and RR. The vehicle is braked well, supplemented by an electric brake device EB for the vehicle. When the vehicle speed V is large or the absolute value | θf | of the steering angle θf is large and an abnormality occurs in one or both of the left and right front wheels FL and FR, the left and right rear wheels RL and RR Increase in braking force is prohibited,
Locking of the wheels due to an increase in the braking force is prevented beforehand, and the running stability of the vehicle is ensured.

When the vehicle speed V is high to some extent and the absolute value | θf | of the steering angle θf is high, the left and right front wheels FL,
If an abnormality occurs in one of the FR brake systems,
The application of the braking force to the left and right rear wheels RL, RR opposite to the side where the abnormality has occurred is prohibited. Such left and right rear wheels R
By changing the distribution of the braking force between L and RR, the generation of a rotational moment about the vertical axis acting on the vehicle body due to the application of the braking force to the wheels is suppressed, and traveling stability can be ensured.

In this modification, step S
In the processing of steps S70 and S78, the braking force of the rear wheel on the side opposite to the front wheel where the abnormality has occurred is set to "0". Instead, the braking torque of the rear wheel is reduced to the value of step S62.
Target braking torque T _L * set at, by suppressing to a value smaller than T R _*, it may be to suppress the occurrence of rotational moment of the vehicle due to the braking force. Further, also in the suppression of the braking force to the rear wheels, the vehicle speed V increases, and / or the absolute value of the steering angle .theta.f | .theta.f | target braking torque T _L * according to increases, the T R _* small ( It may be set to a value (approaching "0").

Next, a case where an abnormality has occurred in the electric brake device EB for the left and right rear wheels RL, RR will be described. Computer 71 of electric brake controller 70
Is stored in the ROM in parallel with the rear wheel braking program shown in FIG.
10 is repeatedly executed.

This electric system abnormality program includes step S
The process is started at 100, and at step S102, abnormality of the computer 71 and the operation amount sensor 51 is determined. The abnormality of the computer 71 means a runaway of the computer 71 detected by a watchdog timer (not shown) or the like. The abnormality of the operation amount sensor 51 is to detect a disconnection, a short circuit, and the like around the sensor 51. An abnormality has occurred in the computer 71 and the operation amount sensor 51, and "YES" in step S102.
When the determination is made, the program proceeds to step S104, and after the processing in step S104, the execution of the electrical system abnormality program is temporarily terminated in step S116.

In step S104, the operation stop of the electric brakes 60a and 60b is controlled. Stopping the operation of the electric brakes 60a and 60b means stopping the execution of the rear wheel braking program in FIG. 3 described above. Thus, even if the brake pedal 11 is depressed, the left and right rear wheels R
No braking force is applied to L and RR by the electric brakes 60a and 60b. As a result, the application of an erroneous braking force to the left and right rear wheels RL, RR is avoided, and the running stability of the vehicle is ensured.

On the other hand, if no abnormality has occurred in the computer 71 and the operation amount sensor 51, the process proceeds to step S10.
2 is determined as "NO", and the program proceeds to step S1.
It proceeds to 06. In step S106, it is determined whether an abnormality such as disconnection or short circuit around the braking torque sensors 82a, 82b has occurred. Braking torque sensors 82a, 82b
If no abnormality has occurred in step S106, "NO" is determined in step S106, and the program proceeds to step S112. In step S112, the wheel speed sensor 8
Abnormalities such as disconnection and short circuit around 3a and 83b are determined. If no abnormality has occurred in the wheel speed sensors 83a and 83b, “NO” is determined in the step S112, and the execution of the electric system abnormality program is ended in a step S116. In this state, the rear wheel braking program in FIG. 3 is executed as described above, and the braking force by the electric brakes 60a, 60b is applied to the left and right rear wheels RL, RR in the above-described manner in accordance with the depression operation of the brake pedal 11. Is done.

On the other hand, if an abnormality has occurred in the braking torque sensors 82a and 82b, based on the determination of "YES" in step S106, steps S108 and S
Step 110 is executed. The processing in step S108
Electric motors 61a, 61 according to the rear wheel braking program in FIG.
1b is instructed to switch the control mode. In the state where the braking torque sensors 82a and 82b are abnormal, the torque feedback control (step S20 in FIG. 3) using the electric brake normal control process and the actual braking torque T detected in the hydraulic pressure system abnormal routine in step S24. 4 (control of the functional block diagram of FIG. 4) cannot be performed. Therefore, in this case, it is necessary to perform control that does not use the actual braking torque T, such as the above-described current feedback control or current open loop control (control in the functional block diagram of FIG. 5). As described above, when the switching of the control mode of the electric motors 61a and 61b is instructed by the processing of step S108, the normal control processing of the electric brake of step S20 in FIG. 3 and the hydraulic pressure abnormality routine of step S24 are performed. At the time of execution, the electric motors 61a and 61a are controlled by current feedback control or current open loop control.
b is driven and controlled. As a result, the braking torque sensor 82
Even if an abnormality occurs in a and 82b, the application of the braking force to the left and right rear wheels RL and RR by the depressing operation of the brake pedal 11 is ensured.

The process in step S110 is for instructing a reduction in the gain of the control of the electric motors 61a and 61b by the rear wheel braking program in FIG. As a result, the current control gain of the electric motors 61a and 61b in the current feedback control or the current open loop control decreases, that is, the target current value I with respect to the operation amount (or operation force) F of the brake pedal 11 in the functional block diagram of FIG. * Is set low. Therefore, the left and right rear wheels R provided by the depression operation of the brake pedal 11
The braking force applied to the left and right rear wheels RL and RR is kept low with respect to the left and right front wheels FL and FR. Braking torque sensor 8
When abnormalities occur in the wheels 2a and 82b, the braking torque of the left and right rear wheels RL and RR may not be accurately controlled. However, the gain control prevents the left and right rear wheels RL and RR from being locked. As a result, the running stability of the vehicle is ensured.

If an abnormality has occurred in the wheel speed sensors 83a and 83b, the process of step S114 is executed based on the determination of "YES" in step S112. The processing in step S114 is for instructing a decrease in the gain of the control of the electric motors 61a and 61b by the rear wheel braking program in FIG. As a result, FIG.
Of the electric motor 61 in the torque feedback control (current feedback control or current open loop control in some cases) executed in steps S20 and S24 of FIG.
a, 61b decrease in the current control gain, that is, FIG.
The target braking torque T * with respect to the operation amount (or operating force) F of the brake pedal 11 in the functional block diagram of FIG. 6 (or FIG. 6) (or the operation amount (or operating force) F of the brake pedal 11 in the functional block diagram of FIG. 5). Target current value I
*) Is set low. Therefore, also in this case, the braking force applied to the left and right rear wheels RL and RR by the depression operation of the brake pedal 11 is suppressed to a low level.

In this electric brake device EB,
Antilock brake control (ABS control) is performed by executing a program (not shown), and the left and right rear wheels RL, R
The locking of R is avoided. However, when an abnormality occurs in the wheel speed sensors 83a and 83b, lock of the left and right rear wheels RL and RR cannot be detected.
Therefore, by reducing the control gain of the electric motors 61a, 61b in the process of step S114, a large braking force is not applied to the left and right rear wheels RL, RR, in other words, the left and right rear wheels RL for the left and right front wheels FL, FR. , RR is kept low and the left and right rear wheels R
Locking of L and RR is avoided beforehand, and the running stability of the vehicle is ensured.

As described above, when the electric brake device EB is abnormal, the braking force is not applied to the left and right rear wheels RL and RR, or the braking force to the rear wheels RL and RR is suppressed to a low level. On the other hand, in the left and right front wheels FL and FR, the braking force distribution to the left and right rear wheels RL and RR increases, and the vehicle
In accordance with the depression operation of the brake pedal 11, braking is performed by a braking force on each wheel according to the braking force distribution.
The hydraulic brake device HB for the front left and right wheels FL and FR
Also, the lock of the left and right front wheels FL and FR is avoided by anti-lock brake control (ABS control) (not shown) by the computer 41 of the hydraulic brake controller 40. The antilock brake control is performed when the lock of the left and right front wheels FL and FR is detected based on the wheel speeds Vw1 and Vw2 from the wheel speed sensors 56a and 56b.
a, 25b, 27a, 27b and the electric motor 31 are controlled.

Although not described in the description of the electric system abnormality routine in FIG. 10, when an abnormality occurs in a part or all of the electric brake device EB, the information indicating these abnormalities is stored in the electric brake controller. The computer 71 is supplied from the computer 71 to the computer 41 of the hydraulic brake controller 40. In response to this, the hydraulic brake controller 40 may change the manner in which the braking force is applied to the left and right front wheels FL, FR, and take measures with the hydraulic brake device HB.

For example, although not described above, when an abnormality occurs in only one of the electric motors 61a and 61b and braking force is applied to only one of the left and right rear wheels RL and RR, the left and right front wheels FL , FR, one of the braking forces is reduced, or the application of the braking force is stopped, so that the vehicle is mainly braked by the rear wheel on the normal side and the front wheel at the diagonal position. It is preferable that the rotational moment due to the braking force does not act. In this case, the electromagnetic valves 25a and 25b are determined based on the information indicating the rear wheel in which the abnormality has occurred, the vehicle speed V, and the steering angle θf by a method similar to the method described in the hydraulic system abnormality routine of FIGS. , 27a, 27b, the brake hydraulic pressure supplied to the wheel cylinders 22a, 22b corresponding to the rear wheel on which the abnormality has occurred and the front wheel on the right and left opposite sides may be stopped or reduced.

In the above embodiment, the target braking torque F * or the target current value I * is calculated in accordance with the operation amount (or operation force) F of the brake pedal 11, and the calculated target braking torque F * or target current value I * is calculated. Electric motor 6 according to current value I *
By controlling the driving of the left and right rear wheels R
The braking force by the electric brake device EB is applied to L and RR. However, these left and right rear wheels RL, R
The braking force on R does not depend on the braking force applied to the left and right front wheels FL, FR.
Hydraulic brake device HB for FR and left and right rear wheels RL, RR
Is not fully coordinated with the electric brake device for the vehicle. Hereinafter, by determining the braking force on the left and right rear wheels RL, RR depending on the braking force applied to the left and right front wheels FL, FR, the hydraulic brake device HB for the left and right front wheels FL, FR and the left and right rear wheels RL, RR A modified example of the vehicle brake device in which the electric brake device for the vehicle is sufficiently coordinated will be described.

This modified example is also basically configured as shown in FIG. 1. In this case, the electric brake controller 70 detects the rear wheel load Wr acting on the left and right rear wheels RL and RR. The rear wheel load sensor 88 is connected, and the brake oil pressures M1 and M2 detected by the oil pressure sensors 53a and 53b are supplied. Then, the computer 71 of the electric brake controller 70 repeatedly executes the rear wheel braking program of FIG. 11 every predetermined short time instead of FIG.

The execution of the rear wheel braking program is started in step S120, and if the brake pedal 11 is not depressed as in the case of FIG.
In step S122, "NO" is determined,
At 124, the current of the electric motors 61a and 61b is turned off so that the braking force by the electric brakes 60a and 60b is not applied to the left and right rear wheels RL and RR. Then, in step S148, the execution of the rear wheel braking program is temporarily ended.

When the brake pedal 11 is depressed, "YES" is determined in the step S122, and
In step S126, an abnormality of the computer 71 due to runaway or the like is determined as in the case described above. If an abnormality has occurred in the computer 71, the process proceeds to step S126.
Is determined to be "YES" at step S124.
And the execution of the rear wheel braking program is temporarily terminated in step S148. Thereby, when an abnormality occurs in the computer 71, even if the brake pedal 11 is depressed, the braking force by the electric brakes 60a, 60b is not applied to the left and right rear wheels RL, RR.
Deterioration of running stability of the vehicle due to application of an erroneous braking force is prevented. In this case, the hydraulic brake device HB
The point that the vehicle is braked by the braking force of the left and right front wheels FL and FR is the same as in the above embodiment.

On the other hand, if no abnormality has occurred in the computer 71, "NO" is determined in the step S126, and the hydraulic pressure sensors 53a and 53b are determined in the step S128.
From both liquid chambers 23a, 23 of the tandem master cylinder 23
In addition to the input of the brake oil pressures MP1 and MP2 in b, the rear wheel load Wr is input from the rear wheel load sensor 88.
Next, in step S130, it is determined whether or not the braking torque sensors 82a and 82b are normal, as in the above case.

If the braking torque sensors 82a and 82b are normal, "YES" is determined in the step S130,
The program proceeds to step S132 and subsequent steps. In step S132, the input brake pressure MP1,
After deriving the master cylinder pressure MP (= (MP1 + MP2) / 2) by calculating the average value of MP2, RO
With reference to the braking torque table stored in M, the target braking torque T * corresponding to the master cylinder pressure MP of the tandem master cylinder 23 and the rear wheel load Wr is calculated. As shown by the solid line in the graph of FIG. 12, the braking torque table defines the target braking torque T * with respect to the master cylinder pressure MP for various magnitudes of the rear wheel load Wr. In this case, the master cylinder pressure MP corresponds to the braking force of the left and right front wheels FL and FR, while the target braking torque T * corresponds to the braking force of the left and right rear wheels RL and RR. This corresponds to the ideal braking force distribution between the front and rear wheels. Therefore, step S1
By the process at 32, the target braking torque T * of the left and right rear wheels RL, RR is determined according to the ideal braking force distribution with respect to the depression operation amount (or operation force) F of the brake pedal 11.

After the processing in step S132, in step S134, the wheel speed sensor 83
It is determined whether an abnormality has occurred in a and 83b. If no abnormality has occurred in the wheel speed sensors 83a and 83b, "NO" is determined in the step S134, and the program proceeds to a step S138. Wheel speed sensor 83a,
If an abnormality has occurred in 83b, the aforementioned step S134
Is determined to be "YES" at step S136, and a predetermined value (1-α) is set for the determined target braking torque T * at step S136.
To obtain the target braking torque T * as a value (1−α) · T *
Change to α is a positive small predetermined value. In this case, the target braking torque T * is changed to a value slightly smaller than the value determined in step S132 as shown by a broken line in FIG.

After the determination or change of the target braking torque T *, in step S138, the left and right rear wheels RL, RL,
The electric motors 61a and 61b are controlled such that the RR braking torque becomes the determined or changed target braking torque T *. This control corresponds to the control of blocks B2, B3, etc. other than the block B1 in FIG. Then, in step S148, the rear wheel braking program is temporarily ended.

On the other hand, if abnormality has occurred in braking torque sensors 82a and 82b, "NO" is determined in step S130.
Is determined, and the program proceeds to step S140 and subsequent steps. In step S140, the target current value I * corresponding to the master cylinder pressure MP (= (MP1 + MP2) / 2) and the rear wheel load Wr is calculated with reference to the current table stored in the ROM. I do. As shown in the graph of FIG. 13, the current table defines target current values I * with respect to the master cylinder pressure MP for various sizes of the rear wheel load Wr. And FIG.
The graph of FIG. 4 also corresponds to the ideal braking force distribution of the front and rear wheels. In this case, the target current value I * is set to avoid locking of the left and right rear wheels RL and RR due to a decrease in control accuracy. It is better to set the value slightly smaller than that determined by the ideal braking force distribution of the front and rear wheels. Accordingly, the target current value I * of the left and right rear wheels RL and RR according to the ideal braking force distribution with respect to the operation amount (or operation force) F of the brake pedal 11 is determined by the process of step S140.

After the processing in step S140, step S14 similar to the processing in steps S134 and S136 is performed.
2, the wheel speed sensors 83a, 83
13b, the target current value I * is calculated as shown in FIG.
As shown by a broken line, the value is changed to a value (1−α) · I * slightly smaller than the value determined in step S140. If no abnormality has occurred in the wheel speed sensors 83a and 83b, the target current value I * is kept at the value determined in step S140.

After the determination or change of the target current value I *, in step S146, as in the case of the above-described embodiment, the electric motors 61a and 61b are set so that a current equal to the target current value I * flows therethrough. , 61b. As a result, the electric brakes 60a and 60b
An actuation force corresponding to * is generated, and the left and right rear wheels RL, RR are braked with a braking force corresponding to the actuation force. This control is performed for blocks B12 and B12 other than the block B11 in FIG.
13 corresponds to the control. Then, step S148
, The rear wheel braking program is temporarily terminated. In this case, as in the case described above, the feedback control of the actual current value may be omitted, and the braking force of the left and right rear wheels RL and RR may be controlled only by the feedforward control.

As a result of controlling the braking force of the left and right rear wheels RL, RR by the rear wheel braking program of FIG. 11, the braking force of the left and right rear wheels RL, RR is reduced by the torque feedback control of steps S132 to S138. It is controlled according to the braking force distribution, that is, the left and right front wheels FL, F
Controlled in coordination with the braking force of R, the left and right rear wheels R
It is possible to prevent a situation in which the running stability of the vehicle is deteriorated due to the locking of L and RR and the like. Further, even when an abnormality occurs in the braking torque sensors 82a and 82b, the cooperative control with the left and right front wheels FL and FR is realized by the current control of steps S140 to S146. , Left and right rear wheels R
Locking of L and RR can be avoided.

If an abnormality occurs in the wheel speed sensors 83a, 83b, the above-mentioned steps S134, S13
6, the target braking torque T * or the target current value I * is reduced by the processing of S142 and S144. That is, the control gain of the electric brakes 60a and 60b with respect to the operation amount (or operation force) F of the brake pedal 11 is reduced. Therefore, in a state where an abnormality occurs in the wheel speed sensors 83a and 83b and locking of the left and right rear wheels RL and RR by anti-lock brake control (ABS control) not shown is not avoided, the left and right rear wheels RL and RR are left and right beforehand. Front wheel FL,
The distribution of braking force to FR is reduced, and the left and right rear wheels RL,
Locking of the RR is prevented beforehand, and good running stability of the vehicle is maintained.

In this modification, the left and right front wheels F
Although the case where an abnormality has occurred in the hydraulic brake device HB for L and FR has not been described, even in the case of this modification, when the hydraulic brake device is abnormal, the left and right front wheels of the left and right rear wheels RL and RR are also described. It is preferable to increase the distribution of braking force to FL and FR. In this case, the target braking torque T * determined in step S132 and the target current value I * determined in step S140 may be increased by a predetermined amount. Further, similarly to the case of the above-described embodiment, an abnormality occurs in a situation where an abnormality occurs in the hydraulic brake system of only one of the left and right front wheels FL and FR and no braking force is applied to only one of the front wheels. While increasing the braking force of the left and right rear wheels RL, RR on the same side as the left and right sides,
Reduce or eliminate the braking force of the RR, that is, the right and left rear wheels R
The braking force distribution of L and RR may be changed so that the vehicle is mainly braked by the braking force of the diagonally positioned wheels.

Also in this modification, the left and right rear wheels R
Left and right front wheels FL, FR when an abnormality occurs in L, RR
Is the same as in the above case.

As in the above embodiments and modifications, the hydraulic brake device HB is applied to the left and right front wheels FL and FR, and the electric brake device EB is applied to the left and right rear wheels RL and RR. The vehicle can be stopped using either one of the braking forces when the system is abnormal or when the electric system is abnormal, so that the running stability of the vehicle is properly secured. Also, the hydraulic brake device HB
By adopting both the electric brake device EB and the electric brake device EB, the disadvantages of the two brake devices HB and EB, such as the response delay of the hydraulic brake device HB at a low temperature, are compensated for each other, so that good braking characteristics of the vehicle can be obtained. it can.

In the above-described embodiment and the modified example, the hydraulic brake device HB is applied to the left and right front wheels FL and FR, and the electric brake device EB is applied to the left and right rear wheels RL and RR. Conversely, left and right front wheels F
The electric brake device EB may be applied to L and FR, and the hydraulic brake device HB may be applied to the left and right rear wheels RL and RR. In this case as well, when an abnormality occurs in the hydraulic brake device HB and the braking force of the left and right rear wheels RL and RR decreases, the electric brake device EB is electrically controlled to control the left and right front wheels FL and FR. Improve the braking force, that is, the left and right rear wheels R of the left and right front wheels FL and FR
It is preferable to increase the distribution of the braking force to L and RR so that the insufficient braking force of the left and right rear wheels RL and RR is supplemented by the braking force of the left and right front wheels FL and FR. As a result, the vehicle can be stopped accurately according to the depression operation of the brake pedal 11.

When an abnormality occurs in only one of the left and right rear wheels RL and RR of the hydraulic brake device HB and the braking force of only one of the left and right rear wheels RL and RR is insufficient, the abnormality is detected. The braking force generated by the electric brake device EB for the front wheel on the same side as the rear wheel is generated by increasing or decreasing the braking force generated by the electric brake device EB for the front wheel on the left and right sides, that is, the left and right front wheels FL and FR. The braking force distribution is changed so that the vehicle is mainly braked by the braking force of the wheels at the diagonal positions. As a result, as in the case described above, the generation of the rotational moment of the vehicle due to the braking force can be suppressed, and the running stability of the vehicle improves.

Also, in a modified example in which the electric brake device EB is applied to the left and right front wheels FL and FR, an abnormality occurs in only one of the left and right front wheels FL and FR due to an abnormality in the electric system, and the same wheel is used. When the braking force becomes insufficient or disappears, the hydraulic braking devices of the left and right rear wheels RL and RR are controlled to reduce or eliminate the braking force of the front wheel on which the abnormality has occurred and the rear wheel on the right and left opposite sides, That is, the left and right rear wheels RL,
It is preferable to change the RR braking force distribution so that the vehicle is mainly braked by the braking force of the diagonally positioned wheels.

Further, in implementing the present invention, the hydraulic brake device HB is applied to the left front wheel FL and the right rear wheel RR, and the electric brake device EB is applied to the right front wheel FR and the left rear wheel RL. The hydraulic brake device HB may be applied to the right front wheel FR and the left rear wheel RL, and the electric brake device EB may be applied to the left front wheel FL and the right rear wheel RR. That is, the hydraulic brake device HB and the electric brake device EB are “crossed” (crossed) with respect to the left and right front wheels FL, FR and the left and right rear wheels RL, RR.
May be applied.

The present invention also relates to a six-wheel, eight-wheel
The present invention is also applied to a truck having more than four wheels such as wheels, a trailer (towing vehicle), and the like. Also in this case, the hydraulic brake device HB may be applied to some of the plurality of wheels, and the electric brake device EB may be applied to some or all of the remaining wheels. And when applying the present invention to a trailer (towing vehicle),
It is preferable to apply the electric brake device EB to wheels located far away from the master cylinder so that the delay caused by piping in applying the braking force does not become a problem.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an entire vehicle brake device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the electric drum brake of FIG. 1 in detail.

FIG. 3 is a flowchart of a rear wheel braking program executed by the electric brake controller of FIG. 1;

FIG. 4 is a functional block diagram showing control by the electric brake device of FIG. 1;

FIG. 5 is a functional block diagram showing another control by the electric brake device.

FIG. 6 is a flowchart showing a hydraulic system abnormality routine of the rear wheel braking program of FIG. 3 in detail.

FIG. 7 is a diagram showing a state in which braking force is applied to each wheel according to the control shown in FIG. 6;

8 is a flowchart showing another example of the hydraulic system abnormality routine of FIG. 6 in detail.

FIGS. 9A to 9C are graphs showing control modes of the braking force of the left and right rear wheels that change according to the steering angle and the vehicle speed.

FIG. 10 is a flowchart of an electric system abnormality program executed by the electric brake controller of FIG. 1;

FIG. 11 is a flowchart illustrating another example of a rear wheel braking program executed by the electric brake controller of FIG. 1;

12 is a graph showing a change characteristic of a target braking torque with respect to a master cylinder oil pressure used by executing the program of FIG. 11;

FIG. 13 is a graph showing a change characteristic of a target current value with respect to a master cylinder oil pressure used by executing the program of FIG. 11;

[Explanation of symbols]

HB: hydraulic brake device, EB: electric brake device, 11: brake pedal, 12: parking pedal,
21a, 21b: hydraulic brake, 22a, 22b: wheel cylinder, 23: tandem master cylinder, 40:
Hydraulic brake controller, 41 ... Computer, 51
... Operation amount sensor, 52 ... Brake pedal switch, 53
a, 53, 54a, 54b: oil pressure sensor, 55: vehicle speed sensor, 56a, 56b: wheel speed sensor, 60a, 60b
... Electric brake, 61a, 61b ... Electric motor, 70 ...
Electric brake controller, 71 ... Computer, 81
... parking brake switches, 82a, 82b ... braking torque sensors, 83a, 83b ... wheel speed sensors, 84
a, 84b: motor current sensor, 85: steering angle sensor, 8
6: shift position sensor, 88: rear wheel load sensor.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60T 17/18 B60T 17/18 (72) Inventor Takayuki Yamamoto 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Stock Inside the company (72) Inventor Naoki Sawada 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (72) Inventor Seiichi Kojima 2-1-1, Asahi-cho, Kariya-shi, Aichi F-term ( Reference) 3D045 BB02 BB05 BB37 CC00 CC01 EE21 GG00 GG01 GG26 GG27 GG28 3D046 BB01 BB28 BB31 BB32 CC02 CC06 EE01 EE02 HH00 HH02 HH03 HH07 HH08 HH16 HH22 HH36 HH52 H03 HR03 BB01 MM03 BB01 CC RR35 3D049 BB02 BB05 CC02 CC07 HH20 HH47 HH51 HH53 RR01 RR04 RR05 RR10 RR11 RR13

Claims (12)

[Claims] 1. A hydraulic brake device applied to wheels belonging to a first group among a plurality of wheels, and applying a braking force by hydraulic fluid to wheels belonging to the first group in response to a brake operation; An electric brake device, which is applied to wheels belonging to a second group different from the first group among the plurality of wheels, and applies a braking force by electric power to wheels belonging to the second group in accordance with a brake operation. A brake device for a vehicle. 2. A vehicle brake device according to claim 1, wherein a distribution of a braking force by said hydraulic brake device and a braking force by said electric brake device is changed and controlled according to a state of the vehicle. A vehicle brake device provided with pressure-electric distribution control means. 3. The vehicle brake device according to claim 2, wherein the state of the vehicle is a state in which a braking force is applied to wheels in accordance with a brake operation, and the hydraulic pressure-electric distribution control means includes: When an abnormality occurs in the state of application of the braking force to any of the wheels, the distribution of the braking force by the hydraulic brake device and the braking force by the electric brake device is changed as compared to when the abnormality does not occur. A vehicle brake device. 4. The vehicle brake device according to claim 2, wherein the plurality of wheels include a front wheel and a rear wheel, and the wheel to which the first group belongs is any one of a front wheel and a rear wheel. On the other hand, the wheels belonging to the second group are the other of the front wheels and the rear wheels, and the state of the vehicle is related to a magnitude of a braking force required according to a brake operation, The hydraulic pressure-electric distribution control means changes distribution of a braking force by the hydraulic braking device and a braking force by the electric braking device in accordance with the magnitude of the requested braking force. Brake device. 5. The vehicle brake device according to claim 2, wherein the hydraulic pressure-electric distribution control means controls a braking force by the electric brake device. A brake device for a vehicle that realizes a change in the distribution of the braking force by using the brake device. 6. The vehicle brake device according to claim 1, wherein at least one of the first group and the second group includes a left wheel and a right wheel, and Right and left distribution control means for controlling the brake device or the electric brake device according to the state of the vehicle to control the distribution of each braking force applied to the left wheel and the right wheel belonging to the one group. Characteristic vehicle brake device. 7. The vehicle brake device according to claim 6, wherein the state of the vehicle is a state in which a braking force is applied to wheels in accordance with a brake operation, and the left / right distribution control unit controls the braking of the wheels. A vehicle that changes the distribution of each braking force applied to the left wheel and the right wheel according to the position of the wheel where the abnormality has occurred in the application state of the braking force when an abnormality occurs in the application state of the power. Brake equipment. 8. The vehicle brake device according to claim 7, wherein the left / right distribution control means changes a distribution of a braking force applied to the left wheel and the right wheel depending on a traveling state of the vehicle. Vehicle brake device. 9. The vehicle brake device according to claim 6, wherein the second group includes a left wheel and a right wheel, and The brake device comprises a pair of electric actuators that independently apply a braking force to the left wheel and the right wheel, and the left / right distribution control unit belongs to the second group by controlling the pair of electric actuators in different modes. A brake device for a vehicle that changes the distribution of the braking force applied to the left wheel and the right wheel. 10. A vehicle brake device according to claim 1, further comprising stop suppression means for stopping or suppressing the operation of said electric brake device according to the state of the vehicle. apparatus. 11. The vehicle brake device according to claim 10, wherein the state of the vehicle is an extremely low-speed running state or a stopped state of the vehicle, and the stop suppressing means is configured to control whether the vehicle is in an extremely low-speed running state or A vehicle brake device that stops or suppresses the operation of the electric brake device when in a stopped state. 12. The vehicle brake device according to claim 10, wherein the state of the vehicle is an operation state of a parking brake, and the stop suppressing means is configured to control the electric brake device during the operation of the parking brake. A vehicle brake device for stopping or suppressing the operation of a vehicle.