JP3208242B2 - Lock prevention device for servo valve in hydraulic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric actuator for generating an operating force corresponding to an input, and a spool valve in which a spool valve element is operated from a closed position to a valve opening direction by the operating force of the electric actuator. Configure the servo valve,
The present invention relates to a lock prevention device for a spool valve in a hydraulic operating device that connects a hydraulic supply source and a hydraulic actuator via the spool valve.

[0002]

2. Description of the Related Art The hydraulic operating device is disclosed in, for example,
As disclosed in Japanese Patent No. 107369, it is known that the present invention is applied to a hydraulic braking device for an automobile.

[0003]

By the way, in a hydraulic braking system for an automobile, if the hydraulic pressure of a hydraulic supply source is set as high as possible, even a wheel brake having a relatively compact oil chamber can exert a large braking force. Therefore, the wheel brake can be made more compact. However, when the hydraulic pressure of the hydraulic pressure supply source becomes higher than a certain value, when the spool pressure of the servo valve receives the hydraulic pressure in a closed state, the spool cylinder and the spool valve body receive an eccentric load due to the hydraulic pressure, and thus the spool pressure is increased. In some cases, the valve locks and does not open when the solenoid is energized, or the opening of the valve is significantly delayed.

The present invention has been made in view of such circumstances, and in a closed state of a spool valve of a servo valve, the hydraulic pressure of a hydraulic supply source is reduced to act on the spool valve. It is an object of the present invention to provide a servo valve lock preventing device in a hydraulic operating device, wherein the lock is prevented from being locked.

[0005]

In order to achieve the above object, the present invention provides an electric actuator for generating an operating force in accordance with an input, and an operating force of the electric actuator for opening a spool valve from a closed position. configure the servo valve and a spool valve which is actuated to the valve direction, the hydraulic actuators formed by connecting the hydraulic source and the hydraulic actuator via the spool valve, between the pressure source and the servo valve, servo When the valve is closed , lock the servo valve.
A pressure reducing valve that reduces the hydraulic pressure of the hydraulic pressure supply source and transmits it to the servo valve in order to avoid blockage.
Switch the pressure reducing valve to the fully open state in response to the output oil pressure from the valve
A first feature is that a hydraulic adjustment device having a valve opening means is provided.

According to the present invention, there is provided an electric actuator for generating an operating force according to the output hydraulic pressure of a master cylinder, and a spool valve in which a spool valve element is operated from a closed position to a valve opening direction by the operating force of the electric actuator. configure the servo valve from the hydraulic actuators formed by connecting the hydraulic source and the hydraulic actuator via the spool valve, between the pressure source and the servo valve, the locking of the servo valve during non-operation of the master cylinder reduction of transmitting to the servo valve to depressurize the hydraulic pressure of <br/> hydraulic supply source in order to avoid
When the pressure valve and the master cylinder are
The pressure reducing valve is switched to the fully open state in response to the output oil pressure
The second is that the hydraulic adjustment device having the valve opening means is interposed.
The feature of.

[0007]

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

First, the first embodiment of the present invention shown in FIGS.
An example will be described. FIG. 1 is an overall view of a vehicle braking device to which the present invention is applied. In FIG. 1, a piston 3 of a master cylinder M is connected to a brake pedal 1 via a push rod 2. Output port 4 of the master cylinder M is connected to the first inlet ₆₁ of the electromagnetic switching valve 5, Doben 5
Is connected to a wheel brake B (hydraulic actuator). The second inlet 6 ₂ Doben 5 servovalve S
Is connected to the output port 9. Electromagnetic switching valve 5 is in a demagnetized state is adapted to communicate between the first inlet ₆₁ and communicates between the outlet 7 and is energized second inlet 6 ₂ and the outlet 7. Thus, the excited state of the electromagnetic switching valve 5, that is, the first inlet 6
When between ₁ and outlet 7 are in the cutoff state, the stroke accumulators A _S for by accumulating the output hydraulic pressure of the master cylinder M to ensure a depression stroke of the brake pedal 1, the output port 4 and the electromagnetic switching of the master cylinder M Connected between valves 5.

A hydraulic supply P is connected to an input port 8 of the servo valve S via a hydraulic adjustment device R. That is, the hydraulic pressure source P is connected to the input port 15 of the hydraulic pressure adjusting device R, and the input port 8 is connected to the output port 16 thereof.

The hydraulic supply source P includes a hydraulic pump 12 for pumping hydraulic oil from a reservoir 11, an accumulator 13 connected to the discharge side of the hydraulic pump 12, and a hydraulic pump 1
And a pressure switch 14 for controlling the operation of the servo valve S.
0 is released.

The push rod 2 has a tread force sensor 1 for detecting the amount of tread force applied to the brake pedal 1.
The output signal of the pedaling force sensor 17 is input to a control unit 18. The control unit 18 converts the input signal into an electric quantity and applies it to the servo valve S.

A brake sensor 19 for detecting an operation state of the brake pedal 6 is provided opposite to the brake pedal 6, and an output signal of the brake sensor 19 is input to a control unit 18. When the control unit 18 receives a signal from the brake sensor 19 during normal times, the control unit 18 excites the electromagnetic switching valve 5. However, when the control unit 18 receives an output signal from the failure sensor 20 that detects a failure of the hydraulic pressure supply source P or the servo valve S, Brake sensor 1
9 is invalidated.

FIG. 2 is a longitudinal sectional view of the servo valve S. In the figure, a servo valve S is a spool valve 21.
And a linear solenoid 22 (electric actuator) connected to the upper part thereof. Spool valve 21
Is a housing 23, a valve cylinder 24 fitted to the housing 23, a spool valve body 25 fitted to the valve cylinder 24 so as to be able to move up and down, and a return for urging the spool valve body 25 in the ascending direction. A spring 26 and a housing 23
The input port 8, the output port 9 and the discharge port 10
Is provided. Thus, when the spool valve element 25 occupies the upper limit closing position, the input port 8 is shut off and the output port 9 is opened to the discharge port 10, but the spool valve element 25 is lowered. Then, the discharge port 10 is shut off to communicate between the input port 8 and the output port 9 to increase the opening degree.

At the lower part of the valve cylinder 24, there is provided a reaction force device 27 for applying an upward reaction force to the spool valve body 25 in accordance with an increase in the hydraulic pressure of the output port 9.

The linear solenoid 22 has a cylindrical outer yoke 28 connected to the housing 23, an end yoke 29 fixed to the upper end of the outer yoke 28, and a fixed core fixed to the lower end of the outer yoke 28. 30, a coil 31 disposed in an outer peripheral yoke 28, a movable core 32 opposed to the fixed core 30 and fitted to the end yoke 29 so as to be able to move up and down, and fixed to the movable core 32 and And an operating rod 33 projecting from both end faces.
3 is supported by the end yoke 29 and the fixed core 30 via a pair of upper and lower ball bearings 34 and 35 so as to be able to move up and down, and abuts on the upper end of the spool valve body 25. Thus, the linear solenoid 22 generates an electromagnetic force proportional to the amount of electricity applied to the coil 31 between the fixed core 30 and the movable core 32, and applies a downward thrust to the operating rod 33. I have.

FIG. 3 is a longitudinal sectional view of the hydraulic pressure adjusting device R. In the figure, the casing 36 of the hydraulic adjustment device R
Is a stepped cylinder hole 37 with a large diameter portion 37a at the center.
And the input port 15 connected to the right end of the cylinder hole 37 and the output port 16 connected to the left end of the cylinder hole 37. The input port 15 is connected to the hydraulic pump 1
The output port 16 is connected to the input port 8 of the servo valve S.

The cylinder hole 37 has a large diameter portion 37.
A hollow control piston 40 is slidably fitted with a step having a large diameter portion 40a at the center corresponding to the large diameter portion 4a.
The inside of the large diameter portion 37a of the cylinder hole 37 is divided into a right hydraulic chamber 41 and a left atmospheric chamber 42 by Oa, and the hydraulic chamber 41 is connected to the output port 9 of the servo valve S.

The control piston 40 has an annular inward stopper wall 43 at the right end and an annular inward partition wall 44 at an intermediate portion, and the input port 15 can be opened and closed between the stopper wall 43 and the partition wall 44. The valve element 45 and the valve element 45
And a pressure adjusting spring 46 for urging the shutter in a closing direction with a predetermined set load. The partition wall 44 and the cylinder hole 3
A return spring 47 for urging the control piston 40 rightward with a set load greater than that of the pressure adjusting spring 46 is accommodated between the left end walls of the pressure adjusting spring 46.

The input port 15, the valve body 45, and the valve spring 46 constitute a pressure reducing valve 48 for introducing a value obtained by subtracting a predetermined value from the hydraulic pressure of the hydraulic pressure supply source P. When it moves, the stopper wall 43 prevents the valve body 45 from closing and stops the pressure reducing function of the pressure reducing valve 48.

Next, the operation of the first embodiment will be described. If the master cylinder M is not in operation, the wheel brake B is communicated with the oil chamber of the master cylinder M by the electromagnetic switching valve 5, so that the oil chamber of the wheel brake B is opened to the reservoir of the master cylinder M. .

On the other hand, if the hydraulic pressure supply source P is operating normally, the hydraulic pressure enters the input port 15 of the hydraulic pressure adjusting device R, and the control oil pressure is subtracted from the hydraulic pressure by the pressure reducing valve 48 to the control piston 40. Is introduced into the input port 8 of the servo valve S in the closed state through the hollow portion of the valve. Even if the reduced hydraulic pressure acts on the servo valve S in the closed state as an eccentric load, its influence is small and the servo valve S cannot be locked.

Here, when the master cylinder M is operated by depressing the brake pedal 1 in order to perform braking, the control unit 18 first receives the signal from the brake sensor 19, switches the electromagnetic switching valve 5, and The master cylinder M and the wheel brake B are cut off, and the output port 9 of the servo valve S and the wheel brake B are communicated with each other. Is actuated, the operating rod 33 presses the spool valve element 25 of the spool valve 21 with a thrust corresponding to the treading force, and the input port 8 and the output port 9 communicate with each other.

Accordingly, the oil pressure waiting at the input port 8 is output from the output port 9 and transmitted to the wheel brake B to operate it. The oil pressure from the output port 9 is also transmitted to the oil pressure chamber 41 of the oil pressure adjusting device R, and the control piston 40 is moved to the left, whereby the pressure reducing valve 48 is fully opened. Thus, the control piston 40 and the hydraulic chamber 4
1 is an output from the servo valve S when the valve is opened.
The present invention switches the pressure reducing valve 48 to a fully open state in response to oil pressure
The valve opening means of claim 1 is constituted.

For this reason, the hydraulic pressure of the hydraulic pressure source P is
Since the pressure is not depressurized at 8 and passes through the hydraulic pressure adjusting device R, the normal high hydraulic pressure of the hydraulic pressure supply source P is supplied to the wheel brake B via the servo valve S, and the wheel brake B is operated properly.

Next, when the pedaling force is released from the brake pedal 1, the control unit 18 returns the electromagnetic switching valve 5 to the original position, closes the servo valve S, and sets the output port 9
To the discharge port 10 and thus to the reservoir 11. Along with this, the hydraulic chamber 41 of the hydraulic adjustment device R communicating with the output port 9 is also opened to the reservoir 11, so that
The control piston 40 returns to the original position by the force of the return spring 47, and the pressure reducing valve 48 is again operated.

At the time of braking, if the hydraulic pressure source P or the servo valve S is out of order, the control unit 18 receives the signal from the fault sensor 20 and holds the electromagnetic switching valve 5 at the original position. The output hydraulic pressure of M can be transmitted directly to the wheel brake B via the electromagnetic switching valve 5. Therefore, fail safe is ensured.

FIG. 4 shows a second embodiment of the present invention.
The configuration is the same as that of the previous embodiment except that the output port 4 of the master cylinder M is communicated with the hydraulic chamber 41 of the hydraulic pressure adjustment device R. In the figure, portions corresponding to those of the previous embodiment are denoted by the same reference numerals.

According to the second embodiment, when the master cylinder M is not operated, the hydraulic pressure of the hydraulic pressure supply source P is reduced by the pressure reducing valve 48 of the hydraulic pressure adjusting device R in the closed state as in the previous embodiment. Since it acts on the servo valve S, the locked state of the servo valve S can be avoided. When the master cylinder M operates, the control piston 40 of the hydraulic adjustment device R is moved to the left by the output oil pressure of the master cylinder M, the pressure reducing valve 48 is fully opened, and the servo valve S Can be supplied to the wheel brake B via the Thus, the control piston 40 and the hydraulic chamber 4
1 indicates that the master cylinder M
The pressure reducing valve 48 is switched to the fully open state in response to the output hydraulic pressure of
This constitutes the valve opening means of the present invention (claim 2).

Further, even when the electromagnetic switching valve 5 is in a state in which the connection between the master cylinder M and the wheel brake B is shut off,
Since the output oil pressure of the master cylinder M acts on the oil pressure chamber 41 to move the control piston 40 of the oil pressure adjusting device R to the left, the oil pressure adjusting device R also functions as a stroke accumulator. the required stroke accumulator a _S becomes unnecessary.

Although the present invention has been described with reference to the case where the present invention is applied to a hydraulic braking device for an automobile, the present invention is also applicable to various hydraulic operating devices for industrial use. Further, the electric actuator according to the present invention is not limited to the linear solenoid, but may be an electric motor or the like.

[0031]

As described above, according to the first and second aspects of the present invention, when the spool valve of the servo valve is in the closed state, the pressure reducing valve specially provided between the servo valve and the hydraulic pressure supply source is operated.
The pressure reducing function reduces the hydraulic pressure of the hydraulic supply source to act on the spool valve. Therefore, even if the hydraulic pressure of the hydraulic supply source is set sufficiently high, locking in the closed state of the spool valve is avoided. It can be, therefore, the high pressure of the hydraulic supply source, it is possible to compact the hydraulic actuator without interfering with the servo valve.

According to the first feature, in particular, the servo valve
In response to the output oil pressure from the valve when the valve opens,
According to the second feature, when the master cylinder operates, the mass
Each pressure reducing valve responds to the output hydraulic pressure from the
Is equipped with valve opening means for switching the
When the valve is open or the master cylinder is operating,
In addition, the pressure reducing function of the pressure reducing valve can be stopped.
Therefore, a special pressure reducing valve is installed between the servo valve and the hydraulic pressure source.
Despite intervening, high without being disturbed by this
Supply hydraulic pressure to the wheel brakes quickly to ensure that the brakes
Can be activated.

[Brief description of the drawings]

FIG. 1 is an overall view of an automotive hydraulic braking device according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a servo valve in FIG. 1;

FIG. 3 is an enlarged vertical sectional view of a hydraulic pressure adjusting device in FIG. 1;

FIG. 4 is an overall view of an automotive hydraulic braking device according to a second embodiment of the present invention.

[Explanation of symbols]

21: spool valve 22: linear solenoid (electric actuator) 40: control piston (valve opening means) 41: hydraulic chamber (valve opening means) 48: pressure reducing valve B ···· Wheel brake (hydraulic actuator) M ··· Master cylinder P ··· Hydraulic supply source R ··· Hydraulic pressure adjusting device S ··· Servo valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 15/00-17/22 B60T 13/00-13/74 F16K 31/06 330 F16K 31/06 385

Claims (2)

(57) [Claims] An electric actuator (22) for generating an operating force according to an input, and the electric actuator (2).
A servo valve (S) is constituted by the spool valve (21), which is operated in the opening direction from the valve closing position by the spool valve element (25) by the operation force of 2), and the hydraulic pressure is set via the spool valve (21). in the hydraulic actuating device formed by connecting the source (P) and a hydraulic actuator (B), between a hydraulic pressure supply source (P) and a servo valve (S), the servo valve when the valve is closed servo valve (S) ( S) Lock
A pressure reducing valve (48) for reducing the hydraulic pressure of the hydraulic pressure supply source (P) and transmitting the reduced pressure to the servo valve (S) in order to avoid
When the valve (S) is open, it responds to the output hydraulic pressure from the valve (S).
Valve opening means for operating the pressure reducing valve (48) to a fully open state
A lock preventing device for a servo valve in a hydraulic operating device , wherein a hydraulic adjusting device (R) having (40, 41) is interposed. 2. An electric actuator (22) for generating an operating force according to an output oil pressure of a master cylinder (M), and a spool valve element (25) is opened from a closed position by an operating force of the electric actuator (22). A servo valve (S) is constituted by a spool valve (21) operated in the valve direction, and a hydraulic pressure is formed by connecting a hydraulic supply source (P) and a hydraulic actuator (B) via the spool valve (21). in actuators, hydraulic supply source (P) and between the servo valve (S), the servo valve during non-operation of the master cylinder (M) (S) b
A pressure reducing valve (48) for reducing the hydraulic pressure of the hydraulic pressure supply source (P) and transmitting the reduced pressure to the servo valve (S) in order to avoid
When the cylinder (M) is activated, the master cylinder (M)
The pressure reducing valve (48) is fully opened in response to the output hydraulic pressure of
A device for preventing lock of a servo valve in a hydraulic operating device , wherein a hydraulic adjusting device (R) having switching valve opening means (40, 41) is interposed.