JPH0699798A - Brake liquid pressure control device - Google Patents

Abstract

PURPOSE:To prevent an uncomfortable feeling from being exerted on a drive by arranging a check valve to allow only the flow of brake liquid through an orifice communication port to the orifice side between the orifice communication port of a control valve and an orifice. CONSTITUTION:During re-boosting of antiskid control, even when the master cylinder communication port 13 of a control valve 7 is communicated with an orifice communication port 15, brake liquid discharged from a pump is prevented from flowing through the orifice communication port 15 to the control valve 7 by means of a check valve 38. Namely, the brake liquid is caused to flow from an orifice 27 to a wheel cylinder 3 through a switching valve 32 without being returned to a master cylinder 1 through the master cylinder communication port 13. This constitution causes prevention of the delivery pressure of a pump to the master cylinder 1 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for antiskid control, which is mainly used in vehicles.

[0002]

2. Description of the Related Art As a brake hydraulic pressure control device for anti-skid control adopted for the purpose of preventing a tire from falling into a locked state during brake operation, there is a device shown in FIG. The brake fluid pressure control device 60 is provided between a master cylinder 61 that produces a brake fluid pressure and a wheel cylinder 62 that produces a braking force by the brake fluid pressure. To the master cylinder 61, a switching valve 64 that is switched to a position for communicating the wheel cylinder 62 and a position for communicating the variable volume reservoir 63, a pump 65 that sucks and discharges the brake fluid on the reservoir 63 side, and the master cylinder 61. Master cylinder communication port 66, switching valve communication port 67 communicating with switching valve 64, wheel cylinder 62
Between the wheel cylinder communication port 68 and the switching valve communication port 67 communicating with the switch valve 64, and the orifice 69.
A control valve 71 having an orifice communication port 70 connected via the control valve 71 is provided. In addition, in this thing,
The discharge side of the pump 65 has a master cylinder 61 and a control valve 71.
Is connected to the master cylinder communication port 66.

When the anti-skid control depressurizes the switching valve 64 and the wheel cylinder 62 and the reservoir 63 communicate with each other to reduce the brake fluid pressure of the wheel cylinder 62, the control valve 71 is moved to the wheel cylinder communication port 68 side. The liquid pressure of will decrease. In this state, when the anti-skid control repressurizes, the control valve 71 shuts off the communication between the master cylinder communication port 66 and the switching valve communication port 67 and connects the master cylinder communication port 66 and the orifice. Port 70
And the brake fluid pressure generated by the master cylinder 61 from the master cylinder communication port 66 to the orifice communication port 7
0 to the wheel cylinder 62 via the orifice 69 and the switching valve 64 switched again.

[0004]

In the above brake fluid pressure control device, as described above, the discharge side of the pump 65 is connected between the master cylinder 61 and the master cylinder communication port 66 of the control valve 71. Therefore, the discharge pressure of the pump 65 is directly transmitted to the master cylinder 61,
As a result, pedal kickback occurs in the brake pedal and vibrations occur in the brake pedal due to pump pulsation, which causes a problem that the driver is uncomfortable.

Therefore, an object of the present invention is to provide a brake fluid pressure control device which suppresses the occurrence of pedal kickback and the vibration of the brake pedal due to pump pulsation and does not cause the driver to feel uncomfortable. .

[0006]

In order to achieve the above object, a brake fluid pressure control device of the present invention comprises a master cylinder in which a brake fluid pressure is generated and a wheel cylinder in which a braking force is generated by the brake fluid pressure. A switching valve that is provided between the wheel cylinder and the master cylinder side or that connects the wheel cylinder and a variable volume reservoir; and a pump that sucks and discharges the brake fluid on the reservoir side, Master cylinder communication port communicating with the master cylinder, switching valve communication port communicating with the switching valve, wheel cylinder communication port communicating with the wheel cylinder, and connection between the switching valve communication port and the switching valve via an orifice Has an orifice communication port, and at least the wheel cylinder communication port side A control valve that cuts off the communication between the master cylinder communication port and the switching valve communication port and connects the master cylinder communication port and the orifice communication port at the time of re-pressurization of the anti-skid control in which only the pressure is reduced; A check valve that allows only the flow of brake fluid from the orifice communication port to the orifice side is provided between the orifice communication port and the orifice, and the check valve and the orifice Between the discharge side of the pump and a bypass path that bypasses the discharge side of the pump and the reservoir side, and the brake fluid pressure on the discharge side of the pump is on the master cylinder side. A relief valve is provided which opens when a predetermined value is higher than the brake fluid pressure and releases the residual pressure to the reservoir side. There.

[0007]

According to the brake fluid pressure control device of the present invention, a check valve is provided between the orifice communication port of the control valve and the orifice to allow only the flow of the brake fluid from the orifice communication port to the orifice side. Since the discharge side of the pump is connected between the check valve and the orifice, even when the master cylinder communication port and the orifice communication port of the control valve are in communication when the pressure is increased again in anti-skid control, the pump The brake fluid discharged from the orifice will flow from the orifice to the wheel cylinder through the switching valve without flowing from the orifice communication port to the control valve (that is, without being returned to the master cylinder through the master cylinder communication port). . Therefore, the discharge pressure of the pump is not transmitted to the master cylinder side.

Moreover, when the brake fluid pressure on the discharge side of the pump becomes higher than the brake fluid pressure on the master cylinder side by a predetermined value in the bypass path that bypasses the discharge side and the suction side of the pump, the residual pressure is released to the reservoir side. Since the relief valve is provided, the pump discharge pressure that always follows the hydraulic pressure on the master cylinder side is transmitted to the wheel cylinder through the orifice.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A brake fluid pressure control device according to an embodiment of the present invention will be described below with reference to FIGS.

In the figure, reference numeral 1 is connected to a brake pedal 2 to generate hydraulic pressure in response to depression of the brake pedal 2 or the like.
The figure shows a tandem master cylinder having two hydraulic pressure generating chambers (not shown) for transmitting these to, for example, two systems of hydraulic pressure control circuits A and B that are cross-piped. Since the hydraulic pressure control circuit B side has the same configuration as the hydraulic pressure control circuit A side, only the hydraulic pressure control circuit A side will be described.

The hydraulic pressure control circuit A is further divided into two branch systems connected to the respective wheel cylinders 3, and the brake hydraulic pressure control is performed on the hydraulic pressure control circuit A between the master cylinder 1 and the wheel cylinders 3. A device 4 is provided. Here, the wheel cylinder 3 is, for example, a hydraulic operating device for a disc brake or a drum brake. The hydraulic pressure control circuit A has a path 5 connected to a hydraulic pressure generation chamber (not shown) of the master cylinder 1, and the path 5 is divided into two branch system paths 6, each path 6 having a control valve. 7 are provided respectively.

Each of these control valves 7 is provided with a casing 9 having a cylinder hole 8 each having a circular cross section and a plurality of ports for communicating the cylinder hole 8 with the outside. Here, the cylinder hole portion 8 has a large diameter hole portion 10,
A small-diameter hole portion 11 having a smaller diameter than this is provided on the other side, and a tapered hole portion 12 having a tapered shape is connected between them.

Here, the port is a first port 13 provided at a predetermined position orthogonal to the axis of the cylinder hole 8 so that the large diameter hole 10 communicates with the master cylinder 1 via the path 6. The second port 15 provided at a predetermined position orthogonal to the axis of the cylinder hole 8 so that the diameter hole 10 communicates with the passage 14, and the cylinder so that the taper hole 12 side of the small diameter hole 11 communicates with the passage 16. Third port 17 and small diameter hole 11 provided at predetermined positions orthogonal to the axis of hole 8.
The fourth port 19 is provided along the axial direction of the cylinder hole portion 8 so that the bottom side opposite to the tapered hole portion 12 is communicated with the path 18.

A piston 20 is inserted in the casing 9. The piston 20 is slidably fitted in a large diameter shaft portion 21 which is inserted into the large diameter hole portion 10 with a gap and a small diameter hole portion 11. The large-diameter shaft portion 2 has a small-diameter shaft portion 22 and a connecting shaft portion 23 that connects them and has a smaller diameter than these.
A flange portion 24 slidably fitted into the large-diameter hole portion 10 is formed at a predetermined position near the end of the No. 1 opposite to the connecting shaft portion 23. A seal ring (not shown) that seals these gaps is provided between the small diameter shaft portion 22 and the small diameter hole portion 11. A spring 26 having a predetermined biasing force is provided between the flange 24 and the step 25 at the boundary between the large diameter hole 10 and the tapered hole 12 of the casing 9. The piston 20 is urged by a spring 26 so that the end of the large-diameter shaft portion 21 is attached to the casing 9
In the state in which the first port 13, the second port 15 and the third port 17 are in contact with each other, only the hydraulic pressure on the side of the fourth port 19 is reduced to a predetermined level on both sides thereof. When a differential pressure equal to or more than a value is generated and the spring 26 moves against the biasing force of the spring 26, the large diameter shaft portion 21 is brought into contact with the tapered hole portion 12 to communicate the first port 13 and the second port 15 with each other. While maintaining the above, communication between the third port 17 and the first port 13 and the second port 15 is cut off.

The path 14 connected to the second port 15 is connected to the path 16 connected to the third port 17, and an orifice 27 is provided at a predetermined intermediate position thereof. Also, both paths 1 between the second port 15 and the orifice 27
The four are in communication with each other via a path 28.

The path 16 connected to the third port 17 is divided into two paths 29 and 30 on the side opposite to the control valve 7 side from the connection position of the path 14, and one of the divided paths 29 is each. The reservoirs 31 communicating with the corresponding wheel cylinders 3 and the other paths 30 join each other to have a variable capacity reservoir 31.
Is in communication with. An electromagnetic switching valve 32 is provided at the divided position, and the electromagnetic switching valve 32 is provided in the path 1
6 and the path 29 are communicated with each other and the path 30 is closed, and the demagnetization position is provided so that the path 29 and the path 30 are communicated with each other.
Can be switched to an excitation position that closes.

In this embodiment, the route 30 and the route 28 are connected by the route 33.
3 is provided with a pump 34. The pump 34 includes a pump main body 35 that performs suction and discharge, an intake valve 36 that allows only the flow of brake fluid from the passage 30 side to the pump main body 35, and only a flow of brake fluid from the pump main body 35 to the passage 28 side. And a discharge valve 37 that allows the brake fluid on the path 30 side to be sucked and discharged to the path 28 side.

The path 18 connected to the fourth port 19 is connected to a path 29 between the electromagnetic switching valve 32 and the wheel cylinder 3 and communicates with the wheel cylinder 3.

The first port 13 is a master cylinder communication port, the second port 15 is an orifice communication port, the third port 17 is a switching valve communication port, and the fourth port 19 is a wheel cylinder communication port. I am configuring.

Further, in the present embodiment, a reverse flow which allows the flow of the brake fluid from the second port 15 to the path 28 and the orifice 27 side is provided between the path 28 connection position of the path 14 and the second port 15. A stop valve 38 is provided.
As a result, the discharge side of the pump 34 is connected between the check valve 38 and the orifice 27.

Further, in this embodiment, a bypass path 39 for connecting the discharge side of the pump 34 and the suction side of the reservoir 31 and the pump 34 by bypass is provided between the paths 28 and 30. Provided on the bypass path 39 is a relief valve 40 that opens when the discharge pressure of the pump 34 becomes higher than the pressure on the master cylinder 1 side by a predetermined value to allow the residual pressure to escape to the reservoir 31 side.

Further, in the present embodiment, a path 41 connecting the path 6 and the path 30 is provided, and only the flow of the brake fluid from the path 30 side to the path 6 side is provided on the path 41. A return valve 42 is provided which allows it.

Here, as the relief valve 40 and the return valve 42, various configurations can be applied, for example,
As shown in FIG. 2, a relief valve 40 and a return valve 42 may be integrally formed. This is a pump communication chamber 45 having a pump discharge connection port 43 connected to the path 28 and connected to the discharge side of the pump 34, and a pump suction connection port 44 connected to the path 30 and connected to the suction side of the pump 34 and the reservoir 31. And a master cylinder communication chamber 46 that is provided in parallel with and spaced from the pump communication chamber 45 and is connected to the path 6 on the master cylinder 1 side. A communication hole 47 penetrates between the pump communication chamber 45 and the master cylinder communication chamber 46.
A generally cylindrical relief piston 48 is movably fitted in the communication hole 47.

Here, in the pump communication chamber 45, the seat portion 49 is seated and closed, and when the brake fluid pressure introduced from the pump discharge connection port 43 becomes high, the seat portion 49 is separated and pumped. A valve body 50 that connects the discharge connection port 43 and the pump suction connection port 44 is provided. Here, the valve body 50 is provided with a spring 51 for urging the valve body 50 in the seating direction, and the lower end of the relief piston 48 urged by the spring 52 is in contact therewith. As a result, the valve opening pressure of the valve element 50 becomes higher than the pressure on the master cylinder 1 side introduced into the master cylinder communication chamber 46 from the path 6 and applied to the relief piston 48 by a predetermined biasing force of the springs 51 and 52. ing.

A cup 53, which constitutes the main part of the return valve 42, is inserted in the master cylinder communication chamber 46. Here, the cup 53 is connected to the master cylinder communication chamber 46.
When the pressure on the side is higher than the pressure on the side of the pump communication chamber 45, the pressure is expanded to cut off the communication between the master cylinder communication chamber 46 and the pump communication chamber 45, and in the case of the opposite pressure relationship, the master cylinder communication chamber 46 and the pump communication chamber 45 is made to communicate with each other through a gap between the communication hole 47 and the relief piston 48.

The operation of the brake fluid pressure control device 4 having the above configuration will be described below according to the control state.

When the anti-skid control is not activated, the control valve 7 is urged by the spring 26 to bring the large-diameter shaft portion 21 into contact with the casing 9, and the electromagnetic switching valve 32 is connected to the path 16 and the path. It is in a degaussing position where it communicates with 29. In this state, when the brake pedal 2 is depressed, the brake fluid introduced from the master cylinder 1 to the first port 13 of the control valve 7 via the path 6 is in the forward direction from the second port 15 to the path 14. Is introduced into the passage 16 through the check valve 38 and the orifice 27, and is introduced into the passage 16 from the third port 17 on the other hand,
The wheel cylinder 3 is pressurized via the electromagnetic switching valve 32 and the path 29. Almost at the same time, the brake fluid in the route 29 is passed through the route 18 to the fourth port 1 of the control valve 7.
9 and acts on the small diameter shaft portion 22 of the piston 20. In this way, the hydraulic pressure on the side of the fourth port 19 is changed to the piston 20.
The piston 20 does not move in the state where it is acting on. As a result, the brake fluid pressure generated by the master cylinder 1 is transmitted to the wheel cylinders 3.

During depressurization of the anti-skid control, the electromagnetic switching valve 32 is switched to the excitation position for connecting the path 29 and the path 30, so that the communication between the wheel cylinder 3 and the master cylinder 1 side is disconnected and the wheel cylinder 3 is disconnected.
And the reservoir 31 are communicated with each other, and the hydraulic pressure of the wheel cylinder 3 is introduced into the reservoir 31 to be reduced. At this time, the hydraulic pressure acting on the small-diameter shaft portion 22 of the piston 20 entering the control valve 7 from the fourth port 19 is also reduced, whereby a differential pressure is generated on both sides of the piston 20, This differential pressure causes the piston 20 to move toward the fourth port 19 side against the biasing force of the spring 26.

At the time of re-pressurization in the anti-skid control, the piston 20 of the control valve 7 is moved to the fourth port 19 side by the differential pressure generated on both sides as described above, and the large diameter shaft portion 21 is moved to the tapered hole portion of the casing 9. 12 is in contact with,
In this state, the electromagnetic switching valve 32 is switched to a position where the path 16 and the path 29 are communicated with each other. When the pump 34 inhales the brake fluid from the reservoir 31 side and discharges it to the path 28 side, the control valve 7 causes the first port 13 and the second port 1
5, but the check valve 38 is provided on the second port 15 side.
Therefore, the discharged brake fluid does not flow into the control valve 7 from the second port 15 and re-pressurizes the wheel cylinder 3 through the orifice 27. Here, the discharge pressure of the pump 34 is the relief valve 40.
As a result, the brake fluid pressure is always maintained at a level higher than the brake fluid pressure on the master cylinder 1 side by a predetermined value and is transmitted to the wheel cylinders 3.

When the brake pedal 2 is returned during the anti-skid control, the brake fluid pressure in the master cylinder 1 is reduced, so that the brake fluid pressure on the wheel cylinder 3 side is also transmitted via the control valve 7 to the master cylinder 1. I will run to the side. Further, when the brake fluid pressure in the path 6 decreases, the brake fluid pressure in the reservoir 31 is returned to the path 6 side via the return valve 42 provided in the path 41. As a result, it is possible to prevent the brake fluid from remaining in the reservoir 31.

As described above, according to this embodiment, the check valve 38 which allows only the flow of the brake fluid from the second port 15 to the orifice 27 side is provided between the second port 15 of the control valve 7 and the orifice 27. Since the discharge side of the pump 34 is connected between the check valve 38 and the orifice 27, the first port 13 of the control valve 7 is re-pressurized during antiskid control.
Even though the second port 15 and the second port 15 communicate with each other, the brake fluid discharged from the pump 34 flows from the second port 15 to the control valve 7
Orifice 27 without flowing through (ie, without being returned to the master cylinder 1 via the first port 13).
To the wheel cylinder 3. Therefore, since the discharge pressure of the pump 34 is not transmitted to the master cylinder 1 side, it is possible to prevent the generation of pedal kickback and the vibration of the brake pedal 2 due to the pump pulsation, which gives an unpleasant feeling to the driver. Will disappear.

Moreover, the discharge side of the pump 34 and the reservoir 3
The pump 34 is provided in the bypass path 39 that bypasses the first side.
When the brake fluid pressure on the discharge side becomes higher than the brake fluid pressure on the master cylinder 1 side by a predetermined value, the residual pressure is released to the reservoir 31.
Since a relief valve 40 is provided on the side of the wheel cylinder 3, the wheel cylinder 3 always follows the hydraulic pressure on the master cylinder 1 side, and a pump discharge pressure of a predetermined high pressure is transmitted via the orifice 27. In addition, it is possible to prevent overload of the motor that drives the pump 34 without impairing the anti-skid performance, thereby reducing noise generation.

[0033]

As described in detail above, according to the brake fluid pressure control device of the present invention, only the flow of the brake fluid from the orifice communication port to the orifice side is provided between the orifice communication port of the control valve and the orifice. Since a check valve that allows it is provided and the discharge side of the pump is connected between the check valve and the orifice, the master cylinder communication port and the orifice communication port of the control valve at the time of re-pressurization of anti-skid control. Brake fluid discharged from the pump does not flow from the orifice communication port to the control valve (that is, is not returned to the master cylinder via the master cylinder communication port), and the brake fluid discharged from the orifice is connected to the control valve. Through the wheel cylinder.
Therefore, since the discharge pressure of the pump is not transmitted to the master cylinder side, it is possible to prevent the generation of pedal kickback and the vibration of the brake pedal due to the pulsation of the pump, and the driver does not feel uncomfortable. .

Furthermore, when the brake fluid pressure on the discharge side of the pump becomes higher than the brake fluid pressure on the master cylinder side by a predetermined value in the bypass path that bypasses the discharge side and the suction side of the pump, the residual pressure is released to the reservoir side. Since the relief valve is provided, the wheel cylinder always follows the hydraulic pressure on the master cylinder side, and the pump discharge pressure that is higher by a predetermined value than this is transmitted via the orifice, impairing the anti-skid performance. Without overwhelming, it is possible to prevent overloading of the motor that drives the pump, thereby reducing noise generation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an integrated structure of a relief valve and a return valve of a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram schematically showing a conventional brake fluid pressure control device.

[Explanation of symbols]

 1 master cylinder 3 wheel cylinder 4 brake fluid pressure control device 7 control valve 13 first port (master cylinder communication port) 15 second port (orifice communication port) 17 third port (switch valve communication port) 19 fourth port (wheel) Cylinder communication port) 27 Orifice 31 Reservoir 32 Electromagnetic switching valve (switching valve) 34 Pump 38 Check valve 39 Bypass path 40 Relief valve

Claims (1)

[Claims] 1. A master cylinder in which a brake fluid pressure is generated and a wheel cylinder in which a braking force is generated by the brake fluid pressure are provided to connect the wheel cylinder and the master cylinder side or to the wheel cylinder. A switching valve that communicates with a variable capacity reservoir, a pump that sucks and discharges the brake fluid on the reservoir side, a master cylinder communication port that communicates with the master cylinder, a switching valve communication port that communicates with the switching valve, A wheel cylinder communication port communicating with the wheel cylinder and an orifice communication port connected via the orifice between the switching valve communication port and the switching valve are provided, and at least only the hydraulic pressure on the wheel cylinder communication port side has dropped. When re-pressurizing under anti-skid control, the master cylinder A brake fluid pressure control device comprising: a control valve that cuts off communication between the communication port and the switching valve communication port and that connects the master cylinder communication port and the orifice communication port, wherein the orifice communication port and the orifice A check valve that allows only the flow of the brake fluid from the orifice communication port to the orifice side is provided between the check valve and the discharge side of the pump, and the discharge side of the pump is connected between the check valve and the orifice. A bypass path that bypasses the discharge side of the pump and the reservoir side is provided, and when the brake fluid pressure on the discharge side of the pump becomes higher than the brake fluid pressure on the master cylinder side by a predetermined value, the bypass path is opened to release the residual pressure. A brake fluid pressure control device, characterized in that a relief valve for releasing the brake fluid to the side is provided.