JPH1130253A - Brake device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device, which uses a load of a hydraulic pump so as to dispense with a friction member, for a vehicle. SOLUTION: A closed circuit is constructed by connecting a left hydraulic pump 3L, which is connected to a left wheel, and a right hydraulic pump 3R, which is connected to a right wheel, together via a first and second oil passages 21, 22, and a braking variable throttle valve 8B is arranged in a fifth oil passage diverged to a tank 6 from the first and second oil passages 21, 22 via a first and second switching valves 25L, 25R. In a non-braking time, oil is circulated in the left oil pressure pump 3L, the first oil passage 21, the right oil pressure pump 3R, and the second oil passage 3R with no load, so that both hydraulic pumps 3L, 3R generate no braking force. In a braking time, oil discharged to the first and second oil passages 21, 22 by means of both hydraulic pump 3L, 3R is returned to the tank 6 via the braking variable throttle valve 8B from the first and the second switching valves 25L, 25R, and as a result, both the hydraulic pumps 3L, 3R receive loads so as to generate braking force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular braking system for generating a braking force by applying a load to a rotating hydraulic pump connected to wheels.

[0002]

2. Description of the Related Art A yaw moment control device for a vehicle which controls a yaw moment by generating a braking force and a driving force on one and the other of a left hydraulic pump and a right hydraulic pump which are connected to right and left wheels and rotates, respectively. It has already been proposed by the present applicant (see Japanese Patent Application No. 8-324323).

[0003]

Generally, a brake system for a vehicle transmits a brake oil pressure generated by a master cylinder to a brake cylinder by operating a brake pedal, thereby pressing a brake pad against a brake disk by a driving force of the brake cylinder. Brake. In the case of performing braking based on such a frictional force, wear of a friction member such as a brake pad is inevitable, and there is a problem that replacement and maintenance thereof require much labor and cost.

The present invention has been made in view of the above circumstances, and has as its object to provide a vehicular braking device that does not require a friction member by utilizing a hydraulic pump used in the yaw moment control device. I do.

[0005]

In order to achieve the above object, the invention described in claim 1 comprises a left hydraulic pump connected to a left wheel and rotating, and a right hydraulic pump connected to a right wheel and rotating. A first hydraulic path connecting a discharge port of the left hydraulic pump and a suction port of the right hydraulic pump, a second hydraulic path connecting a discharge port of the right hydraulic pump and a suction port of the left hydraulic pump, A first switching valve for returning oil discharged from the discharge port of the pump to the first oil passage to the tank, a second switching valve for returning oil discharged to the second oil passage from the discharge port of the right hydraulic pump to the tank, A variable throttle valve for braking provided between the first and second switching valves and the tank;
A braking force control means for controlling the operation of the switching valve and the variable throttle valve for braking to generate a braking force on the left hydraulic pump and the right hydraulic pump is provided.

According to the above configuration, the hydraulic closed circuit including the discharge port of the left hydraulic pump, the first oil passage, the suction port of the right hydraulic pump, the discharge port of the right hydraulic pump, the second oil passage, and the suction port of the left hydraulic pump. When the oil circulates without load, the left and right hydraulic pumps do not generate a braking force. By switching the first and second switching valves, the oil discharged from the discharge port of the left hydraulic pump to the first oil passage and the oil discharged to the second oil passage from the discharge port of the right hydraulic pump are used for braking. When the oil returns to the tank via the variable throttle valve, the left and right hydraulic pumps generate a braking force due to the load when the oil passes through the variable throttle valve for braking, and the wheels connected to the left and right hydraulic pumps are braked. .

According to a second aspect of the present invention, in addition to the first aspect, a first variable throttle valve provided between the first oil passage and the tank, and a second oil passage and the tank are provided. A second variable throttle valve provided between the first variable throttle valve, a first displacement control means for increasing the discharge capacity of the left hydraulic pump in response to closing of the first variable throttle valve, and a second variable throttle valve in response to closing of the second variable throttle valve. And a second displacement control means for increasing the discharge displacement of the right hydraulic pump.

According to the above configuration, when both the first variable throttle valve and the second variable throttle valve are opened in a state where the braking force according to the first aspect of the present invention is not generated, the first oil passage and the second variable throttle valve are opened. The oil passage is connected to the tank, the left hydraulic pump and the right hydraulic pump are both in a no-load state, and no driving force or braking force is generated on the left and right wheels.

When the first variable throttle valve is throttled, hydraulic pressure is generated in the first oil passage, and the discharge capacity of the left hydraulic pump is increased by the first displacement control means. As a result, braking force is generated on the left wheel,
The right hydraulic pump is in a motor state driven by oil discharged from the left hydraulic pump, and a driving force is generated on the right wheel. As a result, a yaw moment in the left turning direction is generated, and the understeering tendency can be eliminated when the vehicle is turning left, and the oversteering tendency can be eliminated when the vehicle is turning right.

When the second variable throttle valve is throttled, hydraulic pressure is generated in the second oil passage, and the discharge capacity of the right hydraulic pump is increased by the second displacement control means. As a result, a braking force is generated on the right wheel, and the left hydraulic pump is in a motor state driven by oil discharged from the right hydraulic pump to generate a driving force on the left wheel.
As a result, a yaw moment in the right turning direction is generated, and the oversteering tendency can be eliminated when the vehicle is turning left, and the understeering tendency can be eliminated when the vehicle is turning right.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, there is provided a master cylinder for generating a brake hydraulic pressure based on an operation of a brake pedal, and a tread force detecting means for detecting a tread force of the brake pedal. A brake oil pressure adjusting means for adjusting the brake oil pressure generated by the master cylinder under the control of the control means, and a brake cylinder for braking the wheels with the brake oil pressure from the brake oil pressure adjusting means, wherein the control means detects A braking force corresponding to the applied pedaling force is generated by being distributed to the two hydraulic pumps and the brake cylinder.

According to the above configuration, a part of the hydraulic braking force by the brake cylinder is replaced by the braking force generated by the left and right hydraulic pumps, thereby extending the life of the brake pad of the brake cylinder.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 8 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle provided with a driving force / braking force control device, and FIG. 2 is a driving force / braking force control device. FIG. 3 is an explanatory diagram of an operation at the time of oversteer, FIG. 4 is an explanatory diagram of an operation at the time of understeer, FIG. 5 is an explanatory diagram of an operation at the time of reverse running, and FIG. 7
Is a graph showing the braking force distribution characteristics of the rear wheels, and FIG. 8 is an explanatory diagram of the operation during braking.

As shown in FIG. 1, a front engine / front drive vehicle has left and right front wheels W _FL , W as driving wheels driven by an engine E mounted on the front of the vehicle body.
_FR and left and right rear wheels W _RL , W _RR as driven wheels that rotate as the vehicle travels and whose rotation speed is controlled by the driving force / braking force control device 1.

The driving force / braking force control device 1 includes a left rear wheel _WRL.
Pump unit PL having a left hydraulic pump 3L directly connected to and driven by the axle 2L of the right rear wheel _{WRR and} the axle 2R of the right rear wheel WRR
Pump unit PR having a right hydraulic pump 3R, which is directly connected to and driven by, and a discharge port 4 of a left hydraulic pump 3L
L, a first oil passage 21 connecting the suction port 5R of the right hydraulic pump 3R, a second oil passage 22 connecting the discharge port 4R of the right hydraulic pump 3R, and the suction port 5L of the left hydraulic pump 3L, Third oil passage 2 connecting oil passage 21 to tank 6
3 and a fourth oil passage 24 connecting the second oil passage 22 to the tank 6.
A check valve 7L provided in the first oil passage 21 to allow oil to flow from a discharge port 4L of the left hydraulic pump 3L to a suction port 5R of the right hydraulic pump 3R;
A check valve 7R provided in the second hydraulic pump 3R and allowing a flow of oil from the discharge port 4R of the right hydraulic pump 3R to the suction port 5L of the left hydraulic pump 3L, and a first valve comprising a solenoid valve provided in the third oil passage 23. A variable throttle valve 8L, a second variable throttle valve 8R formed of a solenoid valve provided in the fourth oil passage 24, a first switching valve 25L formed of a solenoid valve provided in the first oil passage 21, and a second oil valve. A second switching valve 25R formed of a solenoid valve provided in the passage 22 and a fifth oil passage 26 connecting the first and second switching valves 25L and 25R to the tank 6
And a variable throttle valve 8B for braking composed of a solenoid valve provided in the fifth oil passage 26.

[0017] electronic control unit U comprising a microcomputer includes a steering angle sensor S ₁ for detecting the steering angle based on the rotation angle of the steering wheel H, a yaw rate sensor S ₂ for detecting the vehicle body yaw rate, wheel W _FL ,
Wheel speed sensor S ₃ for detecting the wheel speed of W _FR , W _RL , W _RR
… And the operation of the brake pedal P causes the master cylinder M
The magnitude of the braking oil pressure generated by C, that is, the brake pedal P
A pedal pressure sensor S ₄ for detecting a pedaling force is connected.

The brake hydraulic pressure generated by the master cylinder MC is applied to the brake cylinders B _FL , B _FR , B _RL , and B _RR provided on the four wheels W _FL , W _FR , W _RL , and W _RR , respectively. It is transmitted via the adjusting means 27.

The electronic control unit U is provided with each of the sensors S₁
~ S_FourForce / braking force control device 1 based on signals from
First and second variable throttle valves 8L and 8R, variable throttle valve for braking
8B and controls the operation of the first and second switching valves 25L and 25R.
By doing, the left and right rear wheels W_RL, W_RRBraking force between
While controlling the yaw moment by distributing the driving force,
Left and right rear wheels W_RL, W_RRTo generate braking force
Linda B_FL, B_FR, B _RL, B_RRPart of the braking force generated
To bear. The braking oil pressure adjusting means 27 is provided with an electronic control unit.
Four wheels W based on instructions from knit U_FL, W_FR, W_RL,
W_RRBraking force can be controlled individually,
Anti-lock brake to reduce braking force on lost wheels
Control and between the driving force / braking force control device 1
Controls the distribution of braking force.

Next, the detailed structure of the left and right pump units PL, PR will be described with reference to FIG.

The left hydraulic pump 3L of the left pump unit PL
Comprises a comprises three working chambers 9L ₁ ~9L _3, each working chamber 9L ₁ ~9L ₃ and each discharge port 4L ₁ ~4L ₃ and intake port 5L ₁ ~5L _3. The right hydraulic pump 3R of the right pump unit PR has three working chambers 9R ₁ to 9R ₁ .
Includes a 9R _3, the working chambers 9R ₁ ~9R ₃ each discharge port 4R ₁ ~4R ₃ and the suction port 5R ₁ ~5R
₃ is provided. 3 discharge ports 4 of left hydraulic pump 3L
L ₁ ~4L _3, the first oil passage 21 having a check valve 7L
Through the three suction ports 5R _1-of the right hydraulic pump 3R
Is connected to the 5R _3, the right hydraulic pumps 3 of the discharge port 4R ₁ ~4R ₃ of 3R, the three intake ports 5L ₁ of the left hydraulic pump 3L via the second oil passage 22 having a check valve 7R It is connected to the ~5L _3. An intermediate portion of the first oil passage 21 is connected to the tank 6 via a third oil passage 23 having a first variable throttle valve 8L, and an intermediate portion of the second oil passage 22 is a fourth oil passage having a second variable throttle valve 8R. It is connected to the tank 6 via an oil passage 24.

The left hydraulic pressure branches from the upstream side of the first oil passage 21
Three discharge ports 4L of pump 3L ₁~ 4L_ThreeLinked to
Three oil passages 21L₁~ 21L_ThreeAnd each check valve
Are provided at the downstream side of the first oil passage 21.
Oil passages 21R branching from₁~ 21R_ThreeIs the right hydraulic port
3R suction port 5R of pump 3R₁~ 5R_ThreeCommunicate with
You. Also, the right hydraulic pump branches from the upstream side of the second oil passage 22
3R three discharge ports 4R₁~ 4R_ThreeThree in a row
Oil passage 22R₁~ 22R_ThreeIn addition, each check valve 10
R are provided, and from the downstream side of the second oil passage 22
Three branched oil passages 22L₁~ 22L_ThreeThe left hydraulic pump
3L 3L suction port 5L₁~ 5L_ThreeCommunicate with

The two working chambers 9L _{2 of} the left hydraulic pump 3L,
The suction port 5L _2, 2 pieces of oil passages 22L ₂ leading to 4L _3, 22L ₃ of 9 L _3, the first on-off valve 11L of the first capacity control means consisting of a pilot valve actuated by the hydraulic oil pressure in the oil passage 21L ₁ Provided. The suction ports 5R ₁ , 5R of the two working chambers 9R ₁ , 9R ₃ of the right hydraulic pump 3R.
_The two oil passages 21R ₁ and 21R _{3 connected} to
Second on-off valve 11R as a second capacity control means consisting of a pilot valve actuated by hydraulic pressure of R ₂ is provided.

The first oil passage 21 is provided with a first switching valve 25L composed of a solenoid valve.
By switching L, the oil discharged from the left hydraulic pump 3L to the first oil passage 21 is discharged to the tank 6 via the fifth oil passage 26 provided with the variable throttle valve 8B for braking. A second switching valve 2 made of a solenoid valve is provided in the second oil passage 22.
By switching the second switching valve 25R, the right hydraulic pump 3R discharges the oil discharged to the second oil passage 22 to the tank 6 via the braking variable throttle valve 8B.

Next, the yaw moment control of the vehicle by the driving force / braking force control device 1 will be described. When the yaw moment control is performed, the first and second switching valves 2
The fifth oil passage 26 is divided into the first and second oil passages 2 by 5L and 25R.
The variable throttle valve for braking 8B
Is not working.

The electronic control unit U includes a steering angle sensor S₁
Steering angle and wheel speed sensor S _Three… Detected vehicle speed
The reference yaw rate is calculated based on
The yaw rate sensor S_TwoWith the actual yaw rate detected in
The actual yaw rate matches the reference yaw rate
If so, it is determined that the vehicle is in neutral steer.
As shown, the first variable throttle valve 8L and the second variable throttle valve 8R
Are both kept open.

First variable throttle valve 8L and second variable throttle valve 8
In a state where R is opened, the first oil passage 21 and the second oil passage 22
Are connected through the third oil passage 23 and the fourth oil passage 24, respectively.
The pressure is equal to the atmospheric pressure to communicate with the work 6. This and
And the first and second on-off valves 11L and 11R are both closed.
Yes, 2 working chambers 9L of left hydraulic pump 3L_Two, 9L _Three
Is the suction port 5L_Two, 5L_ThreeIs shut off and operation stops
And two working chambers 9R of the right hydraulic pump 3R₁, 9R
_ThreeIs the suction port 5R₁, 5R_ThreeIs shut off and operation stops
I do.

Therefore, the left hydraulic pump 3L is connected to the second hydraulic passage 2
2 oil, the oil passage 22L ₁ intake port 5L _1, working chamber 9 L _1, supplied to the first oil passage 21 through the discharge port 4L ₁ and the oil passage 21L _1. The right hydraulic pump 3R is
The oil in the oil passage 21 is supplied to the oil passage 21 R ₂ and the suction port 5.
R ₂ , working chamber 9R ₂ , discharge port 4R ₂ and oil passage 22R
Supplied to the second溶油passage 22 via _two. At this time, the first
Since the oil passage 21 and the second oil passage 22 are at atmospheric pressure by opening the first variable throttle valve 8L and the second variable throttle valve 8R, the left hydraulic pump 3L and the right hydraulic pump 3R are connected to the left and right rear wheels W. _RL and W _RR rotate with no load, and neither driving force nor braking force is generated.

If the actual yaw rate exceeds the reference yaw rate, it is determined that the vehicle is over-steering. For example, if the vehicle is turning left, as shown in FIG.
And, the second variable throttle valve 8R connecting the tank 6 is throttled according to the degree of the oversteer tendency, thereby generating a flow path resistance in the fourth oil passage 24. As a result, the second oil passage 2
Increased second pressure, the second on-off valve 11R in the upstream side pressure of the oil passage 22R ₂ is opened, the three all operating conditions working chambers 9R ₁ ~9R ₃ of the right hydraulic pump 3R. On the other hand, since the first variable throttle valve 8L is in the open state and the first oil passage 21 is maintained at the atmospheric pressure, the first on-off valve 11L is in the closed state, and the left hydraulic pump 3L is operated by one operation. only the chamber 9L ₁ becomes the operating state.

The right hydraulic pump 3R connected to the outer turning wheel that is turning left is connected to the second oil passage 22 that is the discharge oil passage.
A load is generated by the increase in the pressure, and the load exerts a braking force on the turning outer wheel. The three working chambers 9R ₁ ~9R ₃
There the right hydraulic pump 3R operating, oil one working chamber 9 L ₁ corresponds to the difference between the discharge amount of the left hydraulic pump 3L operating is supplied to the working chamber 9 L ₁ of the left hydraulic pump 3L,
When the oil drives the left hydraulic pump 3L by motor, a driving force is generated on the turning inner wheel. in this way,
When a braking force is generated on the turning outer wheel and a driving force is generated on the turning inner wheel, a yaw moment that suppresses the turning of the vehicle acts to eliminate the oversteer tendency.

If the actual yaw rate is lower than the reference yaw rate, it is determined that the vehicle is understeering. If the vehicle is turning left, for example, as shown in FIG.
And, the first variable throttle valve 8L connecting the tank 6 is throttled in accordance with the degree of the understeer tendency to generate a flow path resistance in the third oil passage 23. As a result, the first oil passage 2
Increased first pressure, the first on-off valve 11L in the pressure upstream of the oil passage 21L ₁ is opened, the three all operating conditions working chamber 9 L ₁ ～9L ₃ of the left hydraulic pump 3L. On the other hand, since the second variable throttle valve 8R is in the open state and the second oil passage 22 is kept at the atmospheric pressure, the second on-off valve 11R is in the closed state, and the right hydraulic pump 3R operates one operation. only chamber 9R ₂ is activated.

The left hydraulic pump 3L connected to the turning inner wheel during left turning is provided with the first oil passage 21 which is the discharge oil passage.
A load is generated due to the increase in the pressure, and the load exerts a braking force on the turning inner wheel. Also, three working chambers 9L _{1 to} 9L ₃
There a left hydraulic pump 3L operating, oil one working chamber 9R ₂ corresponds to the difference between the discharge amount of the right hydraulic pump 3R operating is supplied to the working chamber 9R ₂ of the right hydraulic pump 3R,
When the oil drives the right hydraulic pump 3R by motor, a driving force is generated on the turning outer wheel. in this way,
When a braking force is generated on the turning inner wheel and a driving force is generated on the turning outer wheel, a yaw moment that assists the turning of the vehicle acts to eliminate the understeer tendency.

Further, when the vehicle travels backward, FIG.
Direction of rotation of both motors 3L, 3R as shown in is reversed, the discharge port 4L ₁ ~4L _3; 4R ₁ inhaled oil from ～4R ₃ intake port 5L ₁ ~5L _3; 5R ₁ ~
It will be discharged from the 5R _3. However, since the suction of the oil is prevented by the check valves 10L ... provided in the oil passage 22L ₁ ~22L ₃ connecting to the discharge port 4L ₁ ~4L ₃ of the left hydraulic pump 3L, left hydraulic pump 3L
The vane retreats inward in the radial direction to be in a no-load state.
Similarly, the discharge port 4R ₁ ~4R ₃ of the right hydraulic pump 3R
Since inhalation of the oil is prevented by the oil passage 22R ₁ ~22R check valve provided in the ₃ 10R ... leading to the right hydraulic pump 3R vane is a no load condition to retract radially inward. As a result, the yaw moment is not controlled when the vehicle travels backward.

As described above, the yaw moment of the vehicle is arbitrarily controlled by the driving force / braking force control device 1 which is small, light and inexpensive only by connecting the left hydraulic pump 3L and the right hydraulic pump 3R by a hydraulic circuit. As a result, undesirable oversteer tendency and understeer tendency can be eliminated.

Next, the braking force control of the rear wheels W _RL and W _RR by the driving force / braking force control device 1 and the braking oil pressure adjusting means 27 will be described.

As shown in FIG. 8, the first and second switching valves 25
L, 25R are turned on, and the fifth oil passage 26 is connected to the first and second oil passages 2.
1 and 22, the left hydraulic pump 3L is connected to the first oil passage 2
The oil discharged to 1 is supplied to the fifth oil passage 26 via the first switching valve 25L without being supplied to the right hydraulic pump 3R. Similarly, the oil discharged to the second oil passage 22 by the right hydraulic pump 3R is Without being supplied to the left hydraulic pump 3L, the second
The oil is supplied to the fifth oil passage 26 via the switching valve 25R. The oil supplied to the fifth oil passage 26 passes through the variable throttle valve 8B for braking and is returned to the tank 6, and at this time, the left and right hydraulic pumps 3L and 3R are adjusted according to the throttle amount of the variable throttle valve 8B for braking. The left and right hydraulic pumps 3
Rear wheels W _RL and W _RR connected to L and 3R are braked.

Now, step S in the flowchart of FIG.
In step 1, when it is detected by a brake switch (not shown) that the brake pedal P is not depressed, in steps S2 and S3, the first and second switching valves 25L and 25R and the variable throttle valve 8B for braking are moved to the positions shown in FIGS. The state at the time of the yaw moment control shown in FIG. 5 is set. That is, the first and second switching valves 2
5L and 25R are in the OFF position (the fifth oil passage 26 is the first and second oil passages).
(A position to be shut off from the oil passages 21 and 22), and the throttle amount of the variable throttle valve 8B for braking is set to zero.

In step S1, the brake pedal P is depressed.
When it is detected that the pedal has been touched, a stepping force sensor is determined in step S4.
S_FourReads the output hydraulic pressure of master cylinder MC detected by
In step S5, the brake pedal P
Is calculated. Subsequently, in step S6, the first and second
By turning on the switching valves 25L and 25R, the fifth oil passage 26
While connecting to the second oil passages 21 and 22, step S7
Calculates the throttle amount of the variable throttle valve 8B for braking, and further
Rear wheel W at step S8_RL, W_RRBrake cylinder B _RL, B_RR
Is calculated. And step
In step S9, the throttle amount is output to the variable throttle valve 8B for braking.
This generates a braking force on the left and right hydraulic pumps 3L, 3R
And the rear wheel W_RL, W_RRBrake amount
The output to the dynamic oil pressure adjusting means 27 allows the rear wheel W_RL, W
_RRBrake cylinder B_RL, B_RRTo generate braking force
You.

As is clear from FIG. 7, the rear wheels W _RL , W _RR
The braking force increases as the pedaling force increases, and the pedaling force becomes a predetermined value P
It is set so that the rate of increase of the pedaling force decreases when it reaches ₀ . In order to obtain such braking force characteristics of the rear wheels W _RL , W _RR , the braking oil pressure adjusting means 27 is provided with a brake cylinder B _RL ,
Rear wheels W _RL by B _RR, braking force W _RR is, performs control so as to increase linearly with an increase in pedal effort. On the other hand, the left and right hydraulic pumps 3L, the braking force of the 3R linear increase with an increase in pedal effort, is held and pedaling force reaches the predetermined value P ₀ at a constant value. As a result, the characteristic shown by the broken line in FIG. 7 can be given to the total braking force of the rear wheels W _RL and W _RR .

As described above, a part of the braking force of the rear wheels W _RL , W _RR is _{replaced by} the braking force of the left and right hydraulic pumps 3L, 3R, whereby the brake cylinder B of the rear wheels W _RL , W _RR is replaced.
The load on _RL and B _RR is reduced, and the life of the brake pad is extended.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the driving force / braking force control device 1 is applied to automatic brake control. First, in step S11, a relative distance and a relative speed with respect to the preceding vehicle are read by a laser radar or the like (not shown), and the vehicle speed detected by the wheel speed sensors S ₃ . The electronic control unit U determines, based on the read data, whether or not it is necessary to perform braking in order to secure an inter-vehicle distance with a preceding vehicle, and if it is necessary to perform braking, it is necessary in step S12. Calculate the appropriate automatic braking amount. And step S13
, The first and second switching valves 25 of the driving force / braking force control device 1
L, 25R are turned ON, and further, in step S14, the throttle amount of the braking variable throttle valve 8B corresponding to the automatic braking amount is calculated, and in step S15, the throttle amount is output to operate the braking variable throttle valve 8B. . As a result, the left and right hydraulic pumps 3L, 3R can generate a braking force without operating the brake pedal P, and the inter-vehicle distance with the preceding vehicle can be ensured.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made.

For example, in the embodiment, the driving force / braking force control device 1 has both the yaw moment control function and the braking force control function. However, only the braking force control function may be provided. Also, in the embodiment, the throttle amount of the variable throttle valve 8B for braking is controlled by the electronic control unit U, but the throttle amount of the variable throttle valve 8B for brake can be controlled using the output oil pressure of the master cylinder MC as the pilot pressure. . In this way, it is possible to generate a braking force corresponding to the treading force on the left and right hydraulic pumps 3L, 3R.

[0045]

According to the first aspect of the present invention, by switching the first and second switching valves,
When oil discharged from the discharge port of the left hydraulic pump to the first oil passage and oil discharged to the second oil passage from the discharge port of the right hydraulic pump are returned to the tank via the variable throttle valve for braking, the oil The right and left hydraulic pumps generate a braking force due to the load when the vehicle passes through the variable throttle valve for braking, and the wheels connected to the left and right hydraulic pumps are braked. This allows
A braking device that does not require a friction member such as a conventional brake pad can be provided.

According to the second aspect of the present invention,
The yaw moment is controlled by generating a braking force and a driving force in one and the other of the left hydraulic pump and the right hydraulic pump which are connected to the right and left wheels and rotate, respectively, to arbitrarily adjust the oversteer tendency and the understeer tendency. Can be.

According to the invention described in claim 3,
By replacing a part of the hydraulic braking force by the brake cylinder with the braking force generated by the left and right hydraulic pumps, the life of the brake pad of the brake cylinder is extended.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle including a driving force / braking force control device.

FIG. 2 is a hydraulic circuit diagram of a driving force / braking force control device.

FIG. 3 is an explanatory diagram of an operation at the time of oversteering.

FIG. 4 is an explanatory diagram of an operation at the time of understeer.

FIG. 5 is an explanatory diagram of an operation during reverse running.

FIG. 6 is a flowchart of a rear wheel braking force control.

FIG. 7 is a graph showing braking force distribution characteristics of rear wheels.

FIG. 8 is an explanatory diagram of an operation during braking.

FIG. 9 is a flowchart of an automatic brake control according to a second embodiment.

[Description of Signs] 3L left hydraulic pump 3R right hydraulic pump 4L discharge port 4R discharge port 5L suction port 5R suction port 6 tank 8L first variable throttle valve 8R second variable throttle valve 8B variable throttle valve for braking 11L first open / close valve (1st capacity control means) 11R 2nd on-off valve (2nd capacity control means) 21 1st oil passage 22 2nd oil passage 25L 1st switching valve 25R 2nd switching valve 27 Brake hydraulic pressure adjustment means B _FL brake cylinder _BFR Brake cylinder B _RL Brake cylinder B _RR Brake cylinder MC Master cylinder P Brake pedal S ₄ Tread force sensor (Tread force detection means) U Electronic control unit (Brake force control means) W _FL Front wheel (wheel) W _FR Front wheel (wheel) W _RL Wheel (wheel, left wheel) W _RR Rear wheel (wheel, right wheel)

Claims (3)

[Claims] A left hydraulic pump (3L) connected to a left wheel (W _RL ) and rotating, and a right hydraulic pump (3L) connected to a right wheel (W _RR ) and rotating.
R), a first oil passage (21) connecting the discharge port (4L) of the left hydraulic pump (3L) and the suction port (5R) of the right hydraulic pump (3R), and the discharge of the right hydraulic pump (3R). A second oil passage (22) connecting the port (4R) and the suction port (5L) of the left hydraulic pump (3L), and a first oil passage (21) from the discharge port (4L) of the left hydraulic pump (3L). A first switching valve (25L) for returning the oil discharged to the tank (6) to the tank (6), and the oil discharged from the discharge port (4R) of the right hydraulic pump (3R) to the second oil passage (22). ), A variable throttle valve for braking (8B) provided between the first and second switching valves (25L, 25R) and the tank (6); The operation of the second switching valves (25L, 25R) and the variable throttle valve for braking (8B) is controlled to control the left hydraulic pressure. Amplifier (3
L) and braking force control means (U) for generating a braking force on the right hydraulic pump (3R). 2. A first variable throttle valve (8L) provided between a first oil passage (21) and a tank (6), and between a second oil passage (22) and a tank (6). A second variable throttle valve (8R) provided and a first displacement control means (1) for increasing the discharge displacement of the left hydraulic pump (3L) in response to closing of the first variable throttle valve (8L).
1L) and a second displacement control means (1) for increasing the discharge displacement of the right hydraulic pump (3R) in response to closing of the second variable throttle valve (8R).
1R). The vehicle braking device according to claim 1, further comprising: 3. A master cylinder (MC) for generating a braking oil pressure based on an operation of a brake pedal (P); a pedaling force detecting means (S ₄ ) for detecting a pedaling force of the brake pedal (P); U) The brake hydraulic pressure adjusting means (27) for controlling the brake hydraulic pressure generated by the master cylinder (MC) under the control of U), and the wheels (W _FL , W _FR , W _RL ) using the brake hydraulic pressure from the brake hydraulic pressure adjust means (27). , W _RR ) and brake cylinders (B _FL , B _FR , B _RL , B _RR ), and the control means (U) applies a braking force corresponding to the detected pedaling force to the two hydraulic pumps. The vehicle braking device according to claim 1, wherein the braking device is generated by being distributed to (3L, 3R) and the brake cylinders ( _BFL , _BFR , _BRL , _BRR ).