JPS63258250A - Brake controller for vehicle - Google Patents

Abstract

PURPOSE:To enable the elimination of a slip and the suitable control of braking force by setting a liquid pressure in a master cylinder at zero and increasing a check pressure toward a return chamber at the time of controlling the acceleration slip of wheels, while lowering the check pressure during lock preventing control. CONSTITUTION:During the operation of a brake 1, the risk of a wheel lock is detected in a logic circuit 7 with the aid of rotary sensors S1, S2 at a driving wheel Fr and a driven wheel Rr, and then a gate valve GV is closed by means of command from the logic circuit 7 so as to seal off brake pressures in wheel cylinders Cd, Cf and a liquid passage 3, and moreover, a built valve BV is closed while a decay valve DV is opened so as to exhaust a liquid pressure in a rear chamber R2 to a reservoir 5, so that lock preventing control starts. And, the shift of a piston P to the rear chamber R2 brings about increase in volume of a liquid feeding chamber R1 so as to reduce the liquid pressures in the cylinders Cd, Cf, so that braking force is reduced. And next, at the time of starting, when the wheel Fr begins to slip, valves GV, KV are closed and the valve BV is opened by means of a command from the circuit 7 so as to supply an accumulator pressure to the rear chamber R2 so that acceleration slip control starts, and the push of the piston P increases the pressure in the cylinder Cd, resulting in the operation of the brake.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vehicle brake control device used in automobiles, etc., which performs wheel lock prevention control during braking and wheel acceleration slip control during starting. The present invention proposes a brake control device with a simple configuration.

(Prior art) In wheel lock control and wheel acceleration slip control, the free space 5. is controlled based on information such as wheel lock or wheel slip. - The hydraulic pressure of the wheel cylinder is regulated in accordance with the hydraulic pressure of the muleta.

During the wheel lock prevention control, it is necessary for the driver to quickly interrupt the brake operation, and for this purpose, a return check valve is required to return the hydraulic pressure of the wheel cylinder to the master cylinder side.

On the other hand, it has become necessary to prevent the control hydraulic pressure for applying brake on the drive wheels from being transmitted to the master cylinder during wheel acceleration slip control.

(Problems to be Solved by the Invention) A function that allows the hydraulic pressure in the wheel cylinder to be reduced according to the driver's will during wheel lock prevention control, and a function that allows control pressure to be transmitted to the master cylinder during wheel acceleration slip control. The present invention proposes a brake control device that can perform the function of preventing this from happening by using a single return valve.

(Means for Solving the Problems) The configuration of the present invention for solving the above problems includes a master cylinder 2 that generates brake fluid pressure, wheel cylinders Cd and Cf of a brake device for driving wheels, and a master cylinder. 2, a normally open gate valve GV is provided in the fluid path a that connects the piston P, and is closed during wheel lock prevention control during braking or wheel acceleration slip control.
a hydraulic control device RC in which the liquid feeding chamber R1 is divided into a liquid feeding chamber R1 and a rear chamber R2, and the liquid feeding chamber R1 looks into a liquid passage 3 that connects the gate valve Gv and the wheel cylinders Cd and Cf;
The accumulator 6 is provided between the accumulator 6 and the rear chamber R2, which accumulates pressure during driving, and is configured to selectively transfer the hydraulic pressure of the accumulator 6 to the rear chamber R2 during wheel lock prevention control or wheel acceleration slip control. A valve device V for introducing or discharging, a return chamber C1 facing the master cylinder 2, and a return chamber C from the wheel cylinders Cd and Cf when the hydraulic pressure in the return chamber C4 is below the set value.
When the check pressure toward 1 is higher than the set value,
This is a vehicle brake control device including a return valve device CV consisting of a valve mechanism C2 that functions to reduce the check pressure.

(Function) In normal brake control using the brake pedal 1, the gate valve GV is open and the hydraulic pressure in the master cylinder 2 is as follows.
It is supplied to wheel cylinders Cd and Cf via gate valve GV.

During wheel acceleration slip control, the hydraulic pressure in the master cylinder 2 is zero and the check pressure from the wheel cylinder Cd toward the return chamber C7 is large, making it possible to apply high pressure to the wheel cylinder Cd and drive. Wheel cylinder CdO hydraulic pressure is controlled to eliminate wheel slip.

In the wheel lock prevention control, since the hydraulic pressure of the master cylinder 2 due to the operation of the brake pedal 1 acts on the return chamber C1, the check pressure of the check valve mechanism C2 becomes low.

As a result, when the brake pedal 1 is released during wheel lock prevention control, the brake fluid in the wheel cylinders Cd, Cf passes through the check valve mechanism C2, which has a low check pressure, to the master cylinders Cd, Cf. The braking force is quickly returned to the desired braking force specified by the brake lever 1.

In this way, in the wheel lock prevention control, the brake force is controlled to be appropriate based on the judgment of the driver.

(Example) Next, an embodiment of the present invention will be described based on the drawings.

FIG. 1 shows the hydraulic circuit, and FIG. 2 shows its control block diagram.

Brake fluid pressure corresponding to the depression force of the brake pedal 1 is generated in the tandem master cylinder 2, and the brake fluid pressure in the fluid chamber A of the master cylinder 2 is applied to the left front drive wheel F, for example.
r and the A-system brake device of the right rear driven wheel Rr, fluid path a
and is supplied via a normally open gate valve GV.

The brake fluid pressure in the fluid chamber B is supplied to the B-system brake equipment of the front right driving wheel (not shown) and the rear left driven wheel, a fluid path, and a gate valve (not shown).

To explain system A representatively, the brake fluid pressure that has passed through the gate valve GV is transferred from the fluid passage 3 to the front left driving wheel F.
It is supplied to the wheel cylinder Cd of the brake device of wheel Rr, and is also supplied to the wheel cylinder Cf of the brake device of the right rear driven wheel Rr via the cut valve KV and the grating/J-lube PCv.

A liquid feeding chamber R4 of a hydraulic control device RC is connected to the liquid passageway 3, and a rear chamber R2 is provided in the hydraulic control device Rc and is separated from this liquid feeding chamber R6 by a piston P of the hydraulic control device RC. There is.

A pump 4 driven by a motor M pumps brake fluid from a reservoir 5 to an accumulator 6.
The fluid pressure is always stored at a constant level while the vehicle is running.

A valve device V composed of, for example, a normally closed built-in valve BV and a decay valve DV is connected to the rear chamber R2, and controls the hydraulic pressure in the rear chamber R2.

That is, the accumulator hydraulic pressure is increased when the built-in valve BV opens,
When the decay valve DV closes, the liquid is supplied to the rear chamber R2, and the piston P moves toward the liquid feed *R1.

The hydraulic pressure in the rear chamber R2 is held when both the build valve BV and the decay valve DV are closed, and the piston P stops.

When the decay valve DV opens while the built valve BV is closed,
The hydraulic pressure in the rear chamber R2 is discharged to the reservoir 5, and the piston P
moves toward the rear chamber R2.

Such opening/closing operations of the built valve BY and the decay valve DV are performed in each of the wheel lock prevention control and the wheel acceleration slip control according to commands from a logic circuit 7, which will be described later.

The liquid path a leading to the master cylinder 2 includes a return valve device Cv.
A return chamber C1 is connected to the wheel cylinders Cd and Cf.
The hydraulic pressure is determined by the check valve mechanism C2 provided in the return valve device CV.
The structure is such that it returns to the return chamber C1 by the operation of.

The illustrated check valve mechanism C2 has a liquid passage 3 in the return chamber C1.
A goal 9 opens and closes a valve seat 8 provided on the side closer to the valve.

That is, the piston 12 that slides into the cylinder 11 is provided with a rod 13 on the return chamber C1 side, and the small spring 14, which reduces the load stretched between the goal 9 and the piston 12, is provided with the rod 13. is biased in a direction away from the ball 9.

The piston assembly 2 is pushed toward the return chamber C4 by a heavily loaded spring 15. If the hydraulic pressure in the return chamber C1 is p, the elasticity of the spring 15 is f4, the elasticity of the small spring 14 is f2, and the cross-sectional area of the piston 12 is A, then (f2+PA)<fl, as shown in FIG. As shown, the rod 13 is in contact with the goal 9.

However, when the hydraulic pressure p rises and the relationship (f2+PA)>f holds, the rod 13 moves toward the ball 9 as shown in FIG.
The check pressure of the valve 9, which is in pressure contact with the valve seat 8 without being separated from the valve seat 8, is extremely low compared to the case shown in FIG.

When the pushing force on the piston 12 due to the hydraulic pressure of the master cylinder connected to the pick and return chamber C1 is less than the set value determined by the elasticities f1 and f2, the check pressure of the check valve mechanism C2 is high. On the other hand, when the pushing force exceeds the set value, the check pressure becomes low.

In a state in which the gate valve GV is closed, hydraulic pressure based on the operation of the hydraulic control device RC acts on the seal 9, and the driver's depression of the brake pedal 1 is also maintained, that is, in the wheel lock prevention control state. , check pressure is low.

During this wheel lock prevention control, when the brake lever 1 is returned to the brake, the hydraulic pressure in the return chamber C1 decreases, and the brake hydraulic pressure in the wheel cylinders Cd and Cf acting on the fluid passage 3 is reduced to 9 is pushed away from the valve seat 8 and is relieved into the return chamber C1, reducing the braking force.

In wheel acceleration slip control when the gate valve GV is closed and the brake target 1 is not operated, the check pressure is large and the goal 9 remains pressed against the valve seat 8 with a strong force. The brake fluid pressure acting on the wheel cylinders Cd and Cf due to the operation of R(> is not transmitted to the master cylinder by the check valve mechanism C2.

Next, an example of control operations in wheel lock prevention control and wheel acceleration slip control will be explained.

During operation of the brake pedal 1, there is a risk of wheel locking due to rotation sensors S1. When the doubling of S2 is detected by the logic circuit 7, the gate valve GV closes based on the logic circuit 70 command, and the wheel cylinder Cd,
Cf and the brake fluid pressure in the fluid path 3 are sealed, the built valve BV is closed, the decay valve DV is opened, the fluid pressure in the rear chamber R2 is discharged to the reservoir 5, and wheel lock prevention control begins.

As a result, the piston P moves toward the rear chamber R2, and as the volume of the liquid feeding chamber R1 increases, the wheel cylinder Cd.

The brake fluid pressure in Ct decreases, and the braking force decreases.

When the risk of wheel locking is eliminated, the logic circuit 7 closes the decay valve DV, so that the above movement of the piston P is stopped,
Brake force is held.

When the wheel speed recovers sufficiently, the built-in valve BV opens, and the accumulator hydraulic pressure is supplied to the rear chamber R2 and the piston P
is pushed toward the liquid feeding chamber R4, the volume of the liquid feeding chamber R1 decreases, the brake fluid pressure increases, and the braking force also increases.

This operation is reversed depending on whether or not the wheels are locked, and the vehicle decelerates.

During this time, the brake pedal 1 remains depressed, so the hydraulic pressure in the return chamber C1 of the return valve device CV remains high, and as mentioned above, the check pressure in the check valve mechanism C2 is low, and the brake pedal 1 By the operation, the brake fluid pressure in the wheel cylinders Cd and Cf is quickly discharged to the master cylinder 2, and the brake can be loosened according to the driver's will.

When the drive wheel Fr starts to slip when starting, the logic circuit 70 commands close the gate valve GV and the cut valve (KV, open the built valve BY (the degay valve DV remains closed), and reduce the accumulator fluid pressure to the rear chamber. R2 is supplied to start wheel acceleration slip control.

As a result, the piston P is pushed toward the liquid feeding chamber R4 side, and the hydraulic pressure within the wheel cylinder Cd is increased, causing the drive wheel Fr
A brake is applied to the drive wheels Fr, and the driving force is suppressed.

When the slip of the drive wheel Fr decreases, the logic circuit 7 closes the built-in valve Bv, so the above-mentioned pushing movement of the piston P is stopped, and the valve 1/- is held.

When the slip disappears, the decay valve DV opens and the rear chamber R
2 is discharged to the reservoir 5, and the piston P is moved to the rear chamber R.
The brake fluid pressure in the wheel cylinder Cd decreases as the wheel moves to the second side, the brake force decreases, and the driving force recovers.

This operation is reversed depending on the magnitude of the slip, and the speed of the vehicle increases.

During this time, the hydraulic pressure of the master cylinder 2 and the hydraulic pressure of the return chamber C1 are zero, so as mentioned above, the check pressure of the check valve mechanism CV is high, and the brake hydraulic pressure of the wheel cylinder Cd is reduced to the return valve mechanism Cv. There is no escape to the master cylinder, and the braking force is controlled by the operation of the hydraulic control device RC.

The logic circuit 7 is constituted by, for example, a microcomputer, and the present invention can be applied to various logic configurations in addition to the control operations exemplified above.

(Effects of the Invention) The vehicle brake control device according to the present invention is configured as described above, and in wheel lock prevention control, the hydraulic pressure of the master cylinder 2 acts on the return chamber C1 of the return valve device Cv. Therefore, the check pressure of the check valve mechanism C2 is low.In wheel acceleration slip control, the hydraulic pressure in the return chamber C1 is zero, so the check pressure of the check valve mechanism C2 is high.

Therefore, when you want to loosen the brake during wheel lock prevention control, all you have to do is return the brake pedal 1, and the check valve mechanism C2 has a low check pressure.
is opened by a small pressure difference between the brake fluid pressure and the master cylinder fluid pressure, and the brake fluid pressure in the wheel cylinder Cd is released to the master cylinder 2 via the check valve mechanism C2.

In the wheel acceleration slip control, since the check pressure is high, the check valve mechanism C2 does not open under normal conditions and can reliably apply braking force to the drive wheels.

In this way, suitable functions for wheel lock prevention control and wheel acceleration slip control can be obtained by the return valve device CV, and a simple hydraulic circuit configuration is sufficient, so the brake control device can be constructed with a small number of parts and a common one. This invention can be controlled by a control method, and this invention has become particularly effective in reducing component costs and simplifying the control method.

[Brief explanation of the drawing]

The figure shows an embodiment of the present invention, and FIG. 1 is a hydraulic circuit diagram;
FIG. 2 is a longitudinal sectional front view of the return valve device.

Claims (1)

[Claims] A normally open valve that is installed in the fluid path that connects the master cylinder that generates brake fluid pressure and the wheel cylinder and master cylinder of the brake system for the driving wheels, and is closed during wheel lock prevention control during braking or wheel acceleration slip control. a hydraulic control device in which the liquid-feeding chamber is divided into a liquid-feeding chamber and a back chamber by a piston, and the liquid-feeding chamber is exposed to a liquid passageway connecting the gate valve and the wheel cylinder;
Provided between the accumulator that accumulates pressure during driving and the accumulator and the rear chamber, to selectively introduce or discharge the hydraulic pressure of the accumulator to the rear chamber during wheel lock prevention control or wheel acceleration slip control. When the hydraulic pressure in the return chamber and the return chamber facing the master cylinder is less than the set value, the check pressure from the wheel cylinder to the return chamber increases, and when it exceeds the set value, the above A brake control device for a vehicle, comprising a return valve device comprising a check valve mechanism that functions to reduce check pressure.