JPH0348927Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an actuator of an anti-skid device for a vehicle, in particular, a hydraulic circuit that connects a brake master cylinder and a wheel brake cylinder of a vehicle. a cut valve for selectively separating the circuit portion and the wheel brake cylinder side hydraulic pressure circuit portion; an accumulator for accumulating power hydraulic pressure equal to or higher than the maximum value of brake hydraulic pressure at which the wheel is close to being locked; and the wheel brake cylinder side hydraulic pressure circuit portion; It is moved forward by the hydraulic pressure of the hydraulic pressure circuit part on the brake cylinder side and moved backward by the power hydraulic pressure, and the forward and backward movements close and open the cut valve and the volume of the hydraulic pressure circuit part on the wheel brake cylinder side. a piston that increases and restores the power, and a power hydraulic pressure circuit that connects the accumulator to a fluid chamber formed on one side of the piston to which the power hydraulic pressure is supplied, and a power hydraulic pressure circuit that connects the accumulator to the accumulator. The present invention relates to an actuator for a so-called closed type anti-skid device for a vehicle, which is provided with a switching valve that removes the power hydraulic pressure in the liquid chamber when the temperature is low and supplies the power hydraulic pressure into the liquid chamber in other conditions.

[Conventional technology]

In a conventional closed type actuator, nothing is interposed between the accumulator and the switching valve, and when the wheels are nearly locked due to brake operation, the power hydraulic pressure in the liquid chamber is removed. However, in other states, the high power hydraulic pressure in the accumulator is supplied to the liquid chamber through the switching valve regardless of whether the brake is activated or not.

[Problem that the invention attempts to solve]

In a conventional closed type actuator, the hydraulic pressure supplied to the liquid chamber is the high power hydraulic pressure in the accumulator, so the pressure inside the liquid chamber changes rapidly during its operation (pressure reduction/repressurization operation). Not only does this cause shock and abnormal noise, but the control valve is difficult to operate. Although pressure changes within the liquid chamber can be suppressed by providing an orifice or the like in the liquid inflow passage and liquid outflow passage, the reality is that such means cannot sufficiently suppress the change. Furthermore, in the conventional closed type actuator, the high power hydraulic pressure in the accumulator is repeatedly supplied to the liquid chamber as it is, and this is removed to obtain depressurization/repressurization operation. During operation, the high power hydraulic pressure in the accumulator is consumed in large quantities. Furthermore, in the conventional closed type actuator, the high power hydraulic pressure in the accumulator is supplied to the liquid chamber through the switching valve even when the brake is not operated for a much longer time than when the brake is operated. A large load is applied to the sealing member attached to the piston due to the power hydraulic pressure.

[Means for solving problems]

In order to deal with the above-mentioned problems, the present invention provides, in the above-described actuator, a power hydraulic pressure circuit that connects the accumulator and the switching valve to a master cylinder hydraulic pressure applied from the brake master cylinder when the brake is applied. Accordingly, the power hydraulic pressure supplied from the accumulator is reduced to a hydraulic pressure that is a predetermined amount higher than the master cylinder hydraulic pressure and is supplied to the switching valve, and when the brake is not operated, the hydraulic pressure is reduced to a hydraulic pressure that is higher than the master cylinder hydraulic pressure by a predetermined amount, and when the brake is not operated, the hydraulic pressure is reduced through the switching valve to the fluid chamber. A control valve was provided to maintain the hydraulic pressure in the pressure circuit at a relatively low set point.

[Functions and effects of the idea]

In the present invention, when the brake is applied, the control valve reduces the high power hydraulic pressure in the accumulator to a predetermined value according to the master cylinder hydraulic pressure and supplies it to the switching valve. Since hydraulic pressure is supplied, the pressure change in the liquid chamber during operation of the actuator is suppressed, the generation of shock and abnormal noise is suppressed, and the operation of the actuator becomes easier to control. In addition, in the present invention, the high power hydraulic pressure in the accumulator is reduced by the control valve and applied to the actuator, and this is removed to obtain the operation of the actuator, so the power hydraulic pressure accumulated in the accumulator is consumed. The amount will be reduced compared to before. Furthermore, in the present invention, when the brake is not activated and there is no need to keep the actuator in an operable state, the control valve always maintains the hydraulic pressure in the hydraulic circuit leading to the liquid chamber through the switching valve to a relatively low set value. Therefore, the load due to hydraulic pressure on the seal member attached to the piston can be greatly reduced, and the durability of the seal member can be greatly improved. Even if pressure fluid leaks from the member, the piston, cut valve, etc. can be positioned and fixed in their original positions using hydraulic pressure.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows that the front fluid chamber of a tandem brake master cylinder (hereinafter simply referred to as master cylinder) 12 operated by a brake pedal 10 and a brake booster 11 passes through a brake fluid pressure circuit B1 to a left front wheel brake cylinder (hereinafter simply referred to as master cylinder). right rear wheel cylinder 2 through a brake hydraulic pressure circuit B4 branched from the brake hydraulic pressure circuit B1.
4, and the rear fluid chamber of the master cylinder 12 is connected to the right front wheel cylinder 22 through the brake fluid pressure circuit B2, and is also connected to the left rear wheel cylinder 23 through the brake fluid pressure circuit B3 branched from the brake fluid pressure circuit B2. Each wheel cylinder 21, 22, 2
This figure shows an anti-skid device in which the brake fluid pressures of brakes No. 3 and 24 are independently controlled. Although not shown, a known proportioning valve is interposed in the brake hydraulic pressure circuits B3 and B4.

The anti-skid device includes a sensor 31 that detects the rotation speed of the left front wheel, a sensor 32 that detects the rotation speed of the right front vehicle, a sensor 33 that detects the rotation speed of the left rear wheel, and a sensor 34 that detects the rotation speed of the right rear vehicle.
, a computer 40 , and an actuator 50 . The actuator 50 is connected to the reservoir 5
1. High pressure pump 52, electric motor 53, check valve 54, accumulator 55, control valve 56, solenoid valves 57A, 57B, 57C, cut valve-piston parts 58A, 58B, 58C, 5
8D, bypass valve 59A, 59B, 59C,
It is equipped with 59D.

The reservoir 51 stores the same brake fluid as the brake fluid in the hydraulic circuit extending from the master cylinder 12 to each of the wheel cylinders 21 to 24 as a power hydraulic medium. High-pressure pump 52 is driven by electric motor 52 to pump power hydraulic medium in reservoir 51 through check valve 54 and into accumulator 55 . The accumulator 55 is a gas type equipped with a diaphragm 55a, and when the power hydraulic pressure inside the accumulator 55 is lower than the set value, the pressure switch 55b is turned off and a signal to that effect is sent to the computer 40. , computer 4
0 turns on the drive circuit of the electric motor 52. When the power hydraulic pressure in the accumulator 55 reaches the set value due to the operation of the high pressure pump 52, the pressure switch 5
5b is turned on, the computer 40 rotates the electric motor 53 for a set time after the pressure switch 55b is turned on, and then turns off the drive circuit of the electric motor 53. As a result, the accumulator 55
The power hydraulic pressure ranges from a set value to a value increased by a substantially constant pressure by operating the high pressure pump 52 for the set time period. The set value is set to the maximum brake fluid pressure at which the wheels are nearly locked during braking. This maximum brake fluid pressure is the brake fluid pressure at which the wheels are nearly locked when the road surface is least slippery.

The control valve 56 includes the accumulator 55, each solenoid valve 57A to 57C, and the bypass valve 5.
The valve seat member 56a is interposed in the power hydraulic circuit connecting the valves 9A to 59D, and is assembled into the cylinder 50a provided in the body 50A of the actuator 50, as shown in detail in FIG. , stopper 56b, holder 56c, and plug 56d
, a retainer 56e assembled to the left end of the valve seat member 56a, a spring 56f, and a ball-shaped valve 5.
6g, a valve body 56i that is movably incorporated in the valve seat member 56a in the axial direction and is biased to the right by a spring 56h and abuts against the ball-shaped valve 56g and abuts against the stopper 56b, and the inside of the holder 56c. A first piston 56l is assembled to be slidable in the axial direction in an inner hole provided in the first piston 56, is biased leftward by a spring 56j, and is restricted from moving to the left by a clip 56k, and a first piston 56l is provided in a plug 56d. A second member is slidably assembled in the inner hole in the axial direction.
The piston 56m and the pistons 56l and 56m are assembled to be slidable in the axial direction at their axes, and are biased leftward by a spring 56n to abut against the ball valve portion of the valve body 56i, closing the through hole. Spool 5
6p etc. In addition, the control valve 5
6, a liquid chamber 56q is formed on the left side of the valve seat member 56a and is always in communication with the accumulator 55, and is always in communication with the solenoid valves 57A to 57C and the bypass valves 59A to 59D between the valve seat member 56a and the holder 56c. A liquid chamber 56r that can communicate with the liquid chamber 56q is formed, and a liquid chamber 56s that can communicate with the reservoir 51 at all times and can communicate with the liquid chamber 56r is formed between the holder 56c, the plug 56d, and both pistons 56l and 56m, and the liquid chamber 56s that can communicate with the liquid chamber 56r at all times. A fluid chamber 56t is formed between the brake fluid pressure circuit B1 and the second piston 56m, and is constantly in communication with the front fluid chamber of the foil cylinder 12 through a fluid pressure circuit B5 branched from the brake fluid pressure circuit B1 (see FIG. 1).

This control valve 56 controls the hydraulic pressure in the front liquid chamber of the foil cylinder 12, that is, the foil cylinder hydraulic pressure pm.
When is zero (when the brake is not activated), the ball-shaped valve 56g is in the valve seat member 56 in the illustrated state.
The ball valve portion of the valve body 56i seats on the valve seat provided at the left end of the spool 56p and closes the communication between the liquid chambers 56q and 56r.
Communication between 56s and 56s is cut off. At this time,
A relatively low set value of hydraulic pressure P1 corresponding to the spring force of the spring 56n that biases the spool 56p remains in the liquid chamber 56r. Further, in the control valve 56, when the wheel cylinder hydraulic pressure pm reaches a set value 1 or more during brake operation, the ball-shaped valve 56g, the valve body 56i, both pistons 56l, 56m, and the spool 56p cooperate to each solenoid valve 57A to 56p. The liquid pressure (supply pressure) in the liquid chamber 56r supplied to the liquid chamber 57C and each of the bypass valves 59A to 59D is regulated as shown in FIG. This supply pressure regulation is based on the foil cylinder fluid pressure.
This is done by reducing the power hydraulic pressure pa supplied from the accumulator 55 to a hydraulic pressure that is higher than the foil cylinder hydraulic pressure pm by a predetermined amount in accordance with pm.

Each solenoid valve 57A, 57B, 57C
The operation of each cut valve-piston portion 58A, 58B, 58 is controlled by the computer 40.
These valves independently supply and discharge the hydraulic pressure supplied to C and 58D, and each has the same structure. The configuration of the solenoid valve 57A will be described below as an example. The solenoid valve 57A is composed of an inflow control valve 57a and an outflow control valve 57b, both control valves 57a and 57b.
are configured to be excited at the same time. The inflow control valve 57a assumes the illustrated position by the force of the spring when demagnetized, communicates the liquid chamber 56r of the control valve 56 with the liquid chamber 58a of the cut valve-piston portion 58A through the orifice 57c, and switches against the spring when energized. Communication between both liquid chambers 56r and 58a is cut off. The outflow control valve 57b assumes the illustrated position by the force of the spring during demagnetization to cut off communication between the liquid chamber 58a and the reservoir 51, and switches against the spring when energized to communicate the liquid chamber 58a with the reservoir 51.

Each cut valve - piston part 58A to 58D
have the same structure, and the structure will be explained below using the cut valve-piston portion 58A as an example. The cut valve-piston section 58A includes a cut valve including a valve seat 58b, a valve chamber 58c, a ball-shaped valve 58d, a spring 58e, etc., a control piston 58f, and the control piston 5.
Liquid chambers 58a and 58g formed on both sides of 8f,
A ring-shaped cup seal 58h for brake hydraulic pressure and a ring-shaped cup seal 58i for power hydraulic pressure are attached to the control piston 58f. In this cut valve-piston portion 58A, the liquid chamber 5 is passed through the control valve 56 and the solenoid valve 58A.
When a predetermined power is supplied to the valve 8a, the control piston 58f moves the valve 58d to the valve seat 5.
Notches and passages are provided in the valve chamber 58c, the liquid chamber 58g, and the control piston 58f to connect the master cylinder 12 side hydraulic pressure circuit B1a and the foil cylinder 21 side hydraulic pressure circuit B1b of the brake hydraulic circuit B1 to the valve chamber 58c, the liquid chamber 58g, and the control piston 58f. 58j, a liquid chamber 59f of a bypass valve 59A to be described later, and a valve chamber 59c, and the control piston 58f contacts the valve seat 58b to reduce the volume of the liquid chamber 58g, that is, the volume of the foil cylinder side hydraulic pressure circuit B1b. is minimized. Furthermore, when the fluid chamber 58a is cut off from communicating with the control valve 56 and communicated with the reservoir 51 to discharge the power fluid pressure due to the operation of the solenoid valve 57A, the control piston 58f
is moved to the left by the brake fluid pressure, the valve 58d is seated on the seat portion of the valve seat 58b, communication between the valve chamber 58c and the fluid chamber 58g is cut off, and the brake fluid pressure circuit B1 becomes the wheel cylinder side fluid pressure circuit B1.
The brake fluid pressure applied to the wheel cylinder 21 is reduced by increasing the volume of the wheel cylinder side hydraulic pressure circuit B1b and the master cylinder side hydraulic pressure circuit B1a.

Each of the bypass valves 59A to 59D has the same structure, and the structure thereof will be explained below using the bypass valve 59A as an example. Bypass valve 59
A indicates that when the necessary power hydraulic pressure is not applied to the fluid chamber 58a even when the brake pedal 10 is depressed, such as when the high-pressure pump 52 or the electric motor 53 breaks down or the power hydraulic circuit is defective, the cut valve--piston section 58A is the foil cylinder side hydraulic pressure circuit B1
A and the wheel cylinder side hydraulic pressure circuit B1b are separated, and the cut valve from the master cylinder 12 -
This is to cope with the fact that brake fluid pressure cannot be supplied to the wheel cylinder 21 via the piston portion 58A, and the valve seats 59a, 59b,
Valve chamber 59c, ball-shaped valve 59d, spring 58e (this is also used), operating piston 59e, liquid chambers 59f, 59g, seal ring 5
It is equipped with 9h. In this bypass valve 58A, when a predetermined power hydraulic pressure is supplied to the liquid chamber 59g, the piston 59e seats the valve 59d on the seat portion of the valve seat 59a, and the inner hole of the valve seat 59a, that is, the spring 58e
At the same time, the valve chamber 59c is passed through the liquid chamber 59f and the passage 58j, and the liquid chamber 58 of the cut valve-piston portion 58A is closed.
Connect to g. Further, when the power hydraulic pressure supplied to the liquid chamber 59g becomes lower than a predetermined value, the actuating piston 29e is moved to the right by the force of the spring 58e or the brake hydraulic pressure acting on the valve 59d or the actuating piston 59e. 59d separates from the seat portion of the valve seat 59a and passes through the inner hole of the valve seat 59a from the valve chamber 58c of the cut valve-piston portion 58A to the valve chamber 59c.
brake fluid is allowed to flow into the valve 59.
d is seated on the seat portion of the valve seat 59b, and the backflow of brake fluid from the valve chamber 59 to the fluid chamber 59f is stopped. In such a case, that is, the liquid chamber 5
When the power hydraulic pressure supplied to 9g becomes lower than a predetermined value, the cut valve-piston part 58
The hydraulic pressure in the A fluid chamber 58a also decreases, and the control piston 58f is moved forward by the brake fluid pressure, causing the valve 5 to close.
8d is seated on the seat portion of the valve seat 58b, both liquid chambers 58g and 58f are sealed and the same chamber 5
Fluid outflow to 8g and 58f is stopped, ensuring braking action.

The computer 40 controls the sensor 3 during braking.
The rotational states of the left front wheel, right front wheel, left rear wheel, and right rear wheel are individually detected by analyzing the signals from 1, 32, 33, and 34. For example, when the left front wheel is close to being locked, The solenoid valve 57A is energized to discharge all the power hydraulic pressure supplied to the cut valve-piston section 58A to the reservoir 51, and the brake hydraulic pressure in the wheel cylinder side hydraulic pressure circuit B1b is maintained continuously by the pressure reduction operation of the cut valve-piston section 58A. When the rotation of the left front wheel has sufficiently recovered due to the rotation of the front left wheel, the solenoid valve 57A is demagnetized and power hydraulic pressure is again supplied to the cut valve-piston portion 58A, and the wheel cylinder side is activated by the operation of the cut valve-piston portion 58A. The brake fluid pressure in the hydraulic pressure circuit B1b is increased again.
In this brake fluid pressure re-increase stroke, the computer 40 alternately repeats energization and demagnetization of the solenoid valve 57A, thereby controlling the rate of increase in brake fluid pressure, and the left front wheel is brought into a state close to lock again. Avoid things as much as possible.

By the way, in this embodiment configured as described above, the accumulator 55, each of the solenoid valves 57A to 57C, and each of the bypass valves 59A to
A control valve 56 having a pressure regulation function and a residual pressure holding function is interposed in the power hydraulic circuit connecting 59D, and the control valve 56 transfers the high power hydraulic pressure Pa in the accumulator 55 to the master cylinder when the brake is applied. Each solenoid valve 57A to 57C and each bypass valve 5 are depressurized to a predetermined value according to the hydraulic pressure pm.
9A to 59D, each cut valve -
A reduced hydraulic pressure of a predetermined value is supplied to each liquid chamber 58a of the piston parts 28A to 58D,
Each liquid chamber 58 when the actuator is in operation
Pressure changes within a are suppressed, the occurrence of shock and abnormal noise is suppressed, and the operation of the actuator becomes easier to control. Also, Accumulator 5
5 is reduced by the control valve 56 and supplied to each liquid chamber 58a, and is removed to operate the actuator.
Power hydraulic pressure Pa accumulated in the accumulator 55
consumption will be reduced compared to before. Furthermore, when the brake is not in operation and there is no need to keep the actuator in an operable state, the control valve 56 disconnects the accumulator 55 from each of the solenoid valves 57A to 57C and each of the bypass valves 59A to 59D, and closes each cut valve to the piston portion. 58A~58
In order to remove the hydraulic pressure in the power hydraulic circuit leading to each liquid chamber 58a of C, leaving a slight residual pressure P1, cup seals 58h, 5 are attached to each piston 58f of each cut valve-piston section 58A to 58D.
8i and the seal ring 59h attached to each piston 59e of each bypass valve 59A to 59D, as well as the power hydraulic circuit from the control valve 56 to each liquid chamber 58a of each cut valve-piston portion 58A to 58D. The load on all seal members due to power hydraulic pressure can be greatly reduced, and their durability can be greatly improved.

In addition, in this embodiment, when the brake is not activated, a predetermined residual pressure P1 is maintained in the power hydraulic circuit leading to each liquid chamber 58a of each cut valve-piston portion 58A to 58D by the control valve 56. ,
Each cut valve - each piston 58f of piston portions 58A to 58D and each bypass valve 59A to 59
Each piston 59e of D is positioned at the original position shown and will not move unnecessarily. Furthermore, when the brake is not activated, the control valve 56 disconnects the accumulator 55 from each of the solenoid valves 57A to 57C and each bypass valve 59A to 59D, so that the control valve 56 penetrates through the diaphragm 55a of the accumulator 55 and enters the power hydraulic circuit. Accumulator 55
No gas flows into the brake hydraulic circuit.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention;
FIG. 2 is an enlarged sectional view of the control valve shown in FIG. 1, and FIG. 3 is a characteristic diagram of the control valve shown in FIGS. 1 and 2. Explanation of symbols, 10...brake pedal, 12...
...Brake master cylinder, 21, 22, 23,
24... Wheel brake cylinder, 50... Actuator, 55... Accumulator, 56...
Control valve, 57A, 57B, 57C... Solenoid valve (switching valve), 58A, 58B, 58C, 5
8D...Cut valve-piston part, 58a...
Liquid chamber, 58f... Piston, B1a... Brake master cylinder side hydraulic pressure circuit part, B1b... Wheel brake cylinder side hydraulic pressure circuit part.

Claims (1)

[Scope of utility model registration request] A cut valve for selectively separating a hydraulic circuit connecting a brake master cylinder and a wheel brake cylinder of a vehicle into a brake master cylinder side hydraulic pressure circuit section and a wheel brake cylinder side hydraulic pressure circuit section, and a wheel locking valve. An accumulator that accumulates a power hydraulic pressure equal to or higher than the maximum brake hydraulic pressure that will be in a near state, and an accumulator that is moved forward by the hydraulic pressure of the hydraulic pressure circuit section on the wheel brake cylinder side and is moved back by the power hydraulic pressure, and the forward movement is performed. and a piston that closes and opens the cut valve and increases and restores the volume of the wheel brake cylinder side hydraulic circuit portion by reciprocating movement, and a fluid chamber formed on one side of the piston to which the power hydraulic pressure is supplied. and a power hydraulic pressure circuit connecting the accumulator to remove the power hydraulic pressure in the liquid chamber when the wheels are close to being locked, and to supply the power hydraulic pressure in the liquid chamber in other conditions. In the actuator of the anti-skid device for a vehicle, the actuator is equipped with a switching valve that supplies, in the power hydraulic circuit connecting the accumulator and the switching valve,
When the brake is applied, the power hydraulic pressure supplied from the accumulator is reduced to a hydraulic pressure that is higher than the master cylinder hydraulic pressure by a predetermined amount according to the master cylinder hydraulic pressure applied from the brake master cylinder, and the reduced pressure is supplied to the switching valve. An actuator for an anti-skid device for a vehicle, further comprising a control valve that always maintains the hydraulic pressure in the hydraulic circuit leading to the liquid chamber through the switching valve at a relatively low set value when the brake is not in operation.