JPH0210748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control device for an anti-skid device which controls the brake fluid pressure of a wheel brake device according to the skid condition of a wheel, and in particular, to a hydraulic pressure control device for an anti-skid device that controls the brake fluid pressure of a wheel brake device depending on the skid state of a wheel. intervene,
A hydraulic pressure control valve that controls the brake fluid pressure of the wheel brake device in response to a command from the control unit; a hydraulic pump that pressurizes the brake fluid discharged into the fluid reservoir and returns it to a fluid passage connecting the master cylinder and the hydraulic pressure control valve; The present invention relates to a hydraulic pressure control device for an anti-skid device, including an accumulator connected to a discharge side liquid passage of a hydraulic pump and storing brake pressure fluid discharged from the hydraulic pump.

In this type of hydraulic control device, a gas-filled accumulator has been proposed as an accumulator for accumulating the discharge pressure liquid of the hydraulic pump in order to make the hydraulic control device smaller and lighter.

However, in a gas-filled accumulator, the pressure storage chamber that stores pressurized liquid and the gas pressure chamber that is filled with high-pressure gas are separated by a membrane member made of rubber material, but the gas in the gas pressure chamber is small. However, since the gas passes through the membrane member and diffuses, the gas pressure in the gas pressure chamber gradually decreases. This rate of decrease varies greatly depending on the fluid pressure value in the pressure accumulator; if high-pressure fluid is always stored in the pressure accumulator, the rate of decrease will be very small; If no pressure fluid is stored in the chamber,
The rate of decline increases significantly.

By the way, in the hydraulic pressure control device for an anti-skid device, pressure fluid is supplied to the pressure accumulation chamber of the accumulator only when the anti-skid device is operating, and the pressure in the pressure accumulation chamber is normally zero. Therefore, there is a disadvantage that the gas pressure in the gas pressure chamber decreases over a relatively short period of time.

In the above type of hydraulic pressure control device for an anti-skid device, the brake fluid pressure of the wheel brake device is lowered by discharging the brake fluid of the wheel brake device to the fluid reservoir, and the brake fluid is discharged to the fluid reservoir. At the same time, the brake fluid is pressurized by a hydraulic pump and stored in an accumulator, and when the brake fluid pressure of the wheel brake system is to be increased again, the pressure fluid stored in the accumulator is pumped through a hydraulic pressure control valve. In other words, the brake fluid discharged from the wheel brake device is pressurized and returned to the wheel brake device.
However, when the gas pressure in the accumulator decreases and the hydraulic pressure of the brake fluid stored in the accumulator becomes lower than the hydraulic pressure generated in the master cylinder, when the brake fluid pressure of the wheel brake system is increased again, it is not from the accumulator but from the master cylinder. Since pressure fluid is supplied from the cylinder, the stroke of the master cylinder increases each time the brake pressure increases, and eventually the brake pedal reaches its full stroke, making it impossible to generate sufficient brake fluid pressure. There is a risk.

Additionally, if a check valve is not provided between the master cylinder and the accumulator to prevent the flow of liquid from the master cylinder to the accumulator, if the gas pressure in the accumulator becomes low, the brake pressure generated in the master cylinder will There is a risk that fluid will be absorbed into the accumulator and the wheels will not be adequately braked.

The present invention has been made in view of the above-mentioned problems, and it minimizes the drop in gas pressure due to gas dissipation in a gas-filled accumulator, and
The purpose of this device is to provide a hydraulic pressure control device for an anti-skid device that is equipped with a mechanism that prevents the accumulated liquid pressure from decreasing even when the gas pressure decreases. A check valve whose forward direction is from the discharge side of the hydraulic pump to the accumulator side is interposed in the upstream connection path of the accumulator between the discharge side liquid passage and the accumulator. A pressure holding valve for maintaining the hydraulic pressure in the pressure accumulating chamber of the accumulator at a predetermined value is interposed between the accumulator and the downstream connection path of the accumulator, and the anti-skid device controls the hydraulic pressure in the accumulating chamber of the accumulator. The gas pressure in the gas pressure chamber is maintained at a predetermined value even when not in operation, thereby reducing the pressure difference between the gas pressure chamber and the pressure accumulation chamber and reducing the natural dissipation of gas in the gas pressure chamber. When the pressure drops below a predetermined value, the hydraulic pressure in the pressure accumulator is maintained at a predetermined value by allowing brake pressure fluid to remain in the pressure accumulator, thereby eliminating malfunction of the hydraulic pressure control device due to a drop in gas pressure in the accumulator. It's what I chose to do.

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

In a piping system diagram including a partial sectional view showing an embodiment of the present invention, one hydraulic pressure generation chamber of a master cylinder 1 operated by a brake pedal 2 is connected to a wheel brake (not shown) via a piping 3. The other hydraulic pressure generating chamber is connected to the device, and the other hydraulic pressure generating chamber is connected to the piping 4a,
The first check valve 5 is connected to the input port 6a of the 3-position solenoid valve 6 via the pipe 4b, and is further connected to the input port 6a of the 3-position solenoid valve 6.
It is connected to a hydraulic cylinder 8 of a disc brake 7 constituting a wheel brake device through a pipe 4c from the outlet 6b. Further, the discharge port 6c of the three-position solenoid valve 6 is connected to the connection port 10a of the liquid reservoir 10 via a pipe 9.

The 3-position solenoid valve 6 is connected to the control unit 1
1 to the solenoid 60 via the line 12, it constitutes a hydraulic control valve that controls the brake hydraulic pressure supplied to the hydraulic cylinder 8 of the disc brake 7, and the solenoid 60 When no voltage is applied, it takes the first position A, which connects the input port 6a and the outlet port 6b and blocks the discharge port 6c, and when 1/2 of the total voltage is applied to the solenoid 60, When the input port 6a, the outlet port 6b, and the outlet port 6c are respectively cut off at the second position B, and the full voltage is applied to the solenoid 60, the input port 6a and the outlet port 6b are cut off, and the outlet port 6b is cut off. A third position C is taken which connects the outlet 6b to the outlet 6c. When a brake release signal is generated in the control unit 11, full voltage is applied to the solenoid 60 to take the third position C, and when a brake pressure hold signal is generated, 1/2 voltage is applied to the second position. It takes position B, and when a brake pressure increase signal is generated, no voltage is applied and it takes the first position A.
Further, a second check valve 13 whose forward direction is directed toward the master cylinder 1 is connected between the outlet 6b of the 3-position solenoid valve 6 and the master cylinder 1 via pipes 4d and 4e. . Note that the position of the electromagnetic valve 6 may be changed according to the magnitude of current instead of changing the position according to the magnitude of voltage.

The liquid reservoir 10 includes a main body 15 having a cylinder hole 14 therein, a piston 18 that is slidably inserted into the cylinder hole 14 with a seal ring 16 attached to its outer periphery, and forms a reserve chamber 17 on the upper side. ,
The spring 19 is disposed below the piston 18 and presses the piston 18 toward the reserve chamber 17 with a relatively weak spring force. When the piston 18 is discharged through the hydraulic cylinder 8 , the piston 18 compresses the spring 19 and moves downward, storing the brake fluid from the hydraulic cylinder 8 in the reserve chamber 17 .

The pipe 9 also connects to the suction port 21 of the hydraulic pump 20.
The hydraulic pump 20 is driven by a motor 23 which is started by a current transmitted from the control unit 11 via a line 22. The discharge port 24 of the hydraulic pump 20 is connected to a gas-filled accumulator 26 via piping 25.
is connected to the connection port 28 of the mounting member 27, and further connected from the connection port 29 to the pipe 4b via a pipe 30. The pipes 25 and 30 constitute a discharge side liquid passage of the hydraulic pump 20.

The mounting member 27 is provided with a communication hole 31 for communicating the connection ports 28 and 29 and a mounting hole 32 for mounting the gas-filled accumulator 26 therein, and a threaded portion 33 is formed at the opening of the mounting hole 32. ing.

Between the communication hole 31 and the mounting hole 32, there are first and second stepped holes 34 and 35 that communicate between the two holes.
is provided. A ball valve 37 is disposed in the large diameter portion of the first stepped hole 34 so as to be seated on a valve seat 36 formed in the stepped portion, and is screwed into the large diameter opening.
Valve spring 4 supported at one end by a stopper 39 having 8
0 toward the valve seat side, and the valve seat 36,
The communication hole 31 is connected by the ball valve 37 and the valve spring 40.
Check valve 4 whose forward direction is the direction from to the mounting hole 32
1.

The second stepped hole 35 has a large diameter portion on the communication hole 31 side and a small diameter portion on the mounting hole 32 side, and has a large diameter portion inside the large diameter portion.
A ball valve 43 is arranged so as to be seated on a valve seat 42 formed in the stepped portion. Further, a stepped-shaped intermediate member 44 is slidably fitted into the stepped hole 35 with its large diameter portion facing the atmosphere, and its end surface facing the atmosphere and the left end of the stepped hole 35 are fitted into the stepped hole 35 . Attached retaining ring 45
A load spring 46 set to a predetermined tension is tensioned between the ball valve 43 and the small diameter end surface of the load spring 46 which is in contact with the ball valve 43. Therefore, the ball valve 43 is pressed against the valve seat 42 with a predetermined pressing force by the load spring 46. A pressure holding valve 47 is constituted by a valve seat 42, a ball valve 43, a load spring 46, etc., and the mounting hole 32
Pressure holding valve 4 until the internal pressure reaches a predetermined value.
7 is closed, and when the pressure reaches a predetermined value or more, the pressure holding valve 47 opens and communicates the inside of the mounting hole 32 with the communication hole 31. Further, a part of the second stepped hole 35 forms a connection path 48 that communicates the discharge side liquid passage of the hydraulic pump 20 with the pressure accumulation chamber of the accumulator 26 .

The gas-filled accumulator 26 is of a known type and is partially shown in cross section.
The gas-filled accumulator 26 has, at its left end,
It has a fitting part 50 that fits into the mounting hole 32 of the mounting member 27 and has a threaded part 49 formed on the outer periphery to be screwed with the threaded part 33 thereof, and a hole 51 provided inside has a fitting part 50 formed with a threaded part 49 that is threadedly engaged with the threaded part 33 thereof. A membrane member 52 made of a material is disposed, and a gas pressure chamber 53 is formed inside the membrane member 52, and gas at a predetermined pressure is filled through a gas inlet 54. A pressure accumulation chamber 55 is provided outside the membrane member 52 inside the hole 51.
is formed, and this pressure accumulation chamber 55 communicates with the mounting hole 32 of the mounting member 27 through the through hole 56.

The protection plate 57 is arranged between the left side of the hole 51 and the membrane member 52, and protects the membrane member 52 from being pressed against the opening edge of the through hole 56 and being damaged. Also,
58 is a lock nut.

Further, 59 is a wheel speed detector that transmits a wheel speed signal proportional to the rotational speed of the wheel to the control unit 11.

The operation of this embodiment configured as described above will be explained next.

While the vehicle is running, when a brake pedal 2 is depressed to apply the brakes, brake fluid pressure is generated in the master cylinder 1. However, immediately after the brake pedal 2 is depressed, no wheel skid occurs and the 3-position solenoid valve 6 is demagnetized.
It is in position A. Therefore, the brake pressure fluid generated in the master cylinder 1 is supplied to the wheel brake device (not shown) through the pipe 3, and is also supplied to the wheel brake device (not shown) through the pipe 4.
It is supplied to the hydraulic cylinder 8 of the disc brake 7 through the first check valve 5, the piping 4b, the 3-position solenoid valve 6, and the piping 4c, and brakes the wheels.

When the brake pedal 2 is strongly depressed and the brake fluid pressure in the hydraulic cylinder 8 increases, causing a skid in the wheel, a brake pressure drop signal is generated in the control unit 11, and the full voltage is applied to the solenoid 60, causing the brake pressure to decrease. Position solenoid valve 6 switches to third position c. Then, the communication between the master cylinder 1 and the hydraulic cylinder 8 is cut off, and the brake pressure fluid of the hydraulic cylinder 8 is discharged from the discharge port 6c of the 3-position solenoid valve 6 through the pipe 9 into the reserve chamber 17 of the fluid reservoir 10. be done. At the same time, a motor drive signal is generated in the control unit 11, and the motor 23 is
starts and the hydraulic pump 20 operates. Therefore, the brake fluid discharged into the fluid reservoir 10 is
It is immediately pressurized by the hydraulic pump 20 and discharged from the discharge port 24 into the piping 25 . At this time, 3
Position solenoid valve 6 is in third position c, so piping 4b and 4
Since the flow from the pipe 4b to the pipe 4a is blocked by the first check valve 5, the pressure liquid discharged from the discharge port 24 of the hydraulic pump 20 is , the pressure is the accumulator 26
When the gas pressure becomes higher than the gas pressure in the gas pressure chamber 53, the connection port 28 of the mounting member 27, the communication hole 31, and the check valve 4
1. It flows into the pressure accumulation chamber 55 of the gas-filled accumulator 26 through the through hole 56 and is accumulated in the pressure accumulation chamber 55.

Then, when the brake fluid pressure in the hydraulic cylinder 8 decreases and the skid state of the wheel starts to recover, a 1/2 voltage, which is a brake holding signal, is applied from the control unit 11 to the solenoid 60, and the 3-position solenoid valve 6 takes the second position B. Therefore, the hydraulic cylinder 8 and the piping 4b and the piping 9 are respectively cut off, and the brake fluid pressure of the hydraulic cylinder 8 is maintained constant.

When the wheel speed approaches the vehicle speed and the skid condition is resolved, a brake pressure increase signal is generated in the control unit 11. That is, when the voltage applied to the solenoid 60 becomes zero, the three-position solenoid valve 6 returns to the first position A again and connects the input port 6a and the outlet port 6b. At this time, the gas pressure in the gas pressure chamber of the accumulator 26, that is, the pressure in the pressure accumulator 5
The hydraulic pressure of the brake fluid stored in the master cylinder 5 is set to be slightly larger than the predetermined opening pressure of the pressure holding valve 47, and the hydraulic pressure in the pressure accumulation chamber 55 is transmitted from the master cylinder 1 to the pipe 4a. Since the gas pressure in the gas chamber 53 is set to be sufficiently higher than the liquid pressure in the pressure storage chamber 55, the pressure liquid in the pressure storage chamber 55 flows through the through hole 5.
6. Pressure holding valve 47 opened by the hydraulic pressure of pressure accumulation chamber 55, communication hole 31, connection port 29, piping 3
The brake fluid pressure is supplied to the hydraulic cylinder 8 through the 0, piping 4b and the 3-position solenoid valve 6, and the brake fluid pressure of the hydraulic cylinder 8 increases.

Thereafter, by repeating the above-described operations, the brake fluid pressure in the hydraulic cylinder 8 is optimally controlled.

Then, in order to release the brake, the pedal force applied to the brake pedal 2 is removed and the hydraulic pressure in the master cylinder 1 decreases, and the brake pressure fluid that was being supplied to the hydraulic cylinder 8 of the disc brake 7 is transferred to the pipe 4d. , the second check valve 13 and the piping 4e, and the pressure liquid in the pressure accumulating chamber 55 of the gas-filled accumulator 26 is returned to the master cylinder 1 through the pressure holding valve 47, the communication hole 31, and the piping 30, 4.
It is returned to the master cylinder 1 through the b3 position solenoid valve 6, the pipes 4c and 4d, the second check valve 13, and the pipe 4e. When the hydraulic pressure of the master cylinder 1 becomes zero, the hydraulic pressure of the hydraulic cylinder 8 also becomes zero. However, when the pressure of the pressure liquid in the pressure accumulation chamber 55 decreases to a predetermined opening pressure of the pressure holding valve 47, the pressure holding valve 47 closes and the liquid pressure in the pressure accumulation chamber 55 is maintained at that pressure. Therefore, the pressure difference between the gas pressure in the gas pressure chamber 53 and the liquid pressure in the pressure accumulation chamber 55 is maintained at a small value, so that the gas is diffused from the gas pressure chamber 53 into the pressure accumulation chamber 55 through the membrane member 52. Gas leakage becomes extremely small.

Next, the effect when the gas pressure in the gas pressure chamber 53 decreases due to long-term use will be explained.

When the gas pressure in the gas pressure chamber 53 becomes lower than the opening pressure of the pressure holding valve 47 due to natural diffusion, it is discharged from the hydraulic pump 20 and the check valve 41 of the mounting device 27 is discharged.
The brake pressure fluid that has flowed into the pressure storage chamber 55 through the pressure storage chamber 55 flows out into the communication hole 31 through the pressure holding valve 47 only when the hydraulic pressure in the pressure storage chamber 55 is higher than the opening pressure of the pressure holding valve 47, and flows out into the communication hole 31 through the pressure holding valve 47. When the hydraulic pressure in the pressure storage chamber 55 becomes equal to the valve opening pressure, the pressure liquid in the pressure storage chamber 55 is prevented from flowing out by the pressure holding valve 47. That is, when the gas pressure in the gas pressure chamber 53 decreases, the pressure holding valve 47 causes the pressure liquid to remain in the pressure accumulation chamber 55, reduces the volume of the gas pressure chamber 53, and increases the gas pressure to the above-mentioned valve opening pressure. I have to. Since the gas pressure in the gas pressure chamber 53 decreases only gradually, the amount of liquid remaining in the pressure accumulation chamber 55 is reduced to a very small amount each time the hydraulic pump 20 discharges pressure liquid. It continues to increase.

Therefore, the pressure fluid substantially equal to the opening pressure of the pressure holding valve 47 is stored in the pressure storage chamber 55 of the accumulator 26, and when a brake pressure increase signal is generated in the control unit 11, the pressure fluid is stored in the pressure storage chamber 55 of the accumulator 26. Brake pressure fluid with sufficiently high hydraulic pressure can be supplied from the pressure accumulation chamber 55 to the hydraulic cylinder 8 of the disc brake 7.

Also, from master cylinder 1 to accumulator 2
In this embodiment, in which no check valve is provided to prevent the flow of liquid to the pipes 4a and 6, even if a very high liquid pressure is generated in the master cylinder 1, the pipes 4a,
First check valve 5, piping 4b, 30, connection hole 29,
The pressure fluid can be replenished into the pressure storage chamber 55 of the accumulator 26 via the communication hole 31 and the check valve 41.

As is clear from the above description, according to this embodiment, a gas-filled accumulator that stores the discharge pressure liquid of the hydraulic pump is connected to the discharge side of the hydraulic pump, and the discharge side liquid path and the accumulator chamber of the accumulator are connected. In between, a pressure holding valve is installed to maintain the hydraulic pressure in the accumulator at a predetermined value, and the hydraulic pressure in the accumulator is maintained at a predetermined value. The pressure difference with the gas pressure chamber can always be kept at a small value, and the natural dissipation of gas in the gas pressure chamber can be made extremely small.

In addition, since the pressure holding valve prevents the liquid pressure in the accumulator's pressure chamber from falling below a predetermined value, the decrease in gas pressure due to the dissipation of gas in the gas pressure chamber can be avoided by increasing the amount of liquid remaining in the pressure chamber. Therefore, when a brake pressure increase signal is generated, brake pressure fluid of sufficiently high pressure can be supplied from the accumulator to the wheel brake device.

Note that the present invention is not limited to the above-described embodiments, and can be modified in many ways within the scope of its technical concept. For example, in this embodiment, the pressure holding valve is provided on the mounting member for mounting the accumulator, but it may be assembled integrally with the main body of the gas-filled accumulator. Further, the pressure holding valve is not limited to the type of the embodiment, but may be of a type that opens when the hydraulic pressure in the pressure storage chamber of the gas-filled accumulator exceeds a predetermined value.

As explained above, the present invention uses a pressure holding valve to maintain the hydraulic pressure in the pressure accumulation chamber at a predetermined value or higher, so that the gas-filled accumulator cannot always store hydraulic pressure at a pressure higher than a predetermined value. Therefore, the operation of the anti-skid device can be ensured irrespective of the natural pressure reduction of the gas in the accumulator.

[Brief explanation of drawings]

The figure is a piping system diagram including a partial cross-sectional view, showing an embodiment of the present invention. 1... Master cylinder, 5... First check valve,
6...3 position solenoid valve, 7...disc brake,
DESCRIPTION OF SYMBOLS 10...Liquid reservoir, 11...Control unit, 13...Second check valve, 20...Hydraulic pressure pump, 23...Motor, 24...Discharge port, 26...
...Gas-filled accumulator, 27... Mounting member, 32... Mounting hole, 41... Check valve, 47...
Pressure holding valve, 48...connection path, 52...membrane member,
53...Gas pressure chamber, 55...Pressure accumulation chamber.

Claims (1)

[Claims] 1 A hydraulic pressure control valve that is interposed between the master cylinder and the wheel brake device and controls the brake fluid pressure of the wheel brake device in response to a command from the control unit, and the hydraulic pressure control valve lowers the brake fluid pressure. At this time, a fluid reservoir is provided for storing brake fluid discharged from the wheel brake device via a fluid pressure control valve, and the brake fluid discharged into the reservoir is pressurized to connect the master cylinder and the fluid pressure control valve. Hydraulic pressure control for an anti-skid device, comprising: a hydraulic pump that returns to a liquid passageway to which the brake fluid flows; and a gas-filled accumulator that is connected to the discharge side liquid passage of the hydraulic pump and stores brake pressure fluid discharged from the hydraulic pump. In the apparatus, a check valve whose forward direction is from the discharge side of the hydraulic pump to the accumulator side is interposed in the upstream connection path of the accumulator between the discharge side liquid passage and the accumulator, and , for an anti-skid device comprising a pressure holding valve that maintains the liquid pressure in the pressure accumulation chamber of the accumulator at a predetermined value in a downstream connection path of the accumulator between the discharge side liquid passage and the accumulator. Hydraulic pressure control device.