JP2020203526A - Fluid pressure control unit of brake system for vehicle - Google Patents

Abstract

To provide a brake fluid pressure control device which enables a brake fluid to flow bypassing a damper which absorbs pulsation according to a vehicle brake force required.SOLUTION: A brake fluid pressure control device (20) according to the invention includes: a discharge duct line (38) to which a brake fluid boosted by a pump (45) is discharged; a damper (27) into which the brake fluid flows from the discharge duct line (38); and a bypass valve (39) which guides the brake fluid so that the brake fluid selectively flows through one of a damper duct line (36) into which the brake fluid flowing into the damper (27) flows and a bypass duct line (37) which bypasses the damper (27). The bypass valve (39) includes a piston (391) having a damper duct line opening (393) leading to the damper duct line (36) and a bypass duct line opening (394) leading to the bypass duct line (37).SELECTED DRAWING: Figure 3

Description

The present invention relates to a brake fluid pressure control device for a vehicle brake system, and more particularly to a brake hydraulic pressure device including a pump for increasing the hydraulic pressure of the brake fluid.

A conventional brake fluid pressure control device, a main flow path that communicates the master cylinder and the wheel cylinder, a sub-flow path that allows the brake fluid in the main flow path to escape, and a supply that supplies the brake fluid from the pump in the sub-flow path to the main flow path. Some have a flow path and a hydraulic circuit to have.

For example, the upstream end of the brake fluid flow in the sub-flow path is connected to the wheel cylinder side region of the main flow path with reference to the booster valve, and the downstream end of the sub-flow path is It is connected to the area of the main flow path on the master cylinder side with respect to the booster valve. Further, the upstream end of the brake fluid flow in the supply flow path communicates with the master cylinder, and the downstream end of the supply flow path is the downstream region of the secondary flow path with reference to the pressure reducing valve. And it is connected to the suction side of the pump provided in that area. Further, a circuit control valve is provided in the region of the main flow path on the master cylinder side with reference to the connection portion with the downstream end of the sub flow path, and the suction control valve is provided in the middle of the supply flow path. Is provided.

For example, a brake fluid pressure control device is composed of a pressure boosting valve, a pressure reducing valve, a pump, a circuit control valve, a suction control valve, a housing in which they are incorporated, and an electronic control unit that controls their operation. In the brake hydraulic pressure control device, the hydraulic pressure of the hydraulic pressure circuit is controlled by controlling the operations of the pressure boosting valve, the pressure reducing valve, the pump, the circuit control valve, and the suction control valve.

In particular, when it becomes necessary to increase the hydraulic pressure of the brake fluid of the wheel cylinder regardless of the state of brake operation at the input part of the brake system (for example, the brake pedal), the pressure boosting valve opens and the pressure reducing valve closes. The pump is driven with the circuit control valve closed and the suction control valve open.

When the pump is driven, the pulsation generated in the brake fluid is transmitted from the braking system to the engine compartment of the vehicle, which may generate noise. This noise may be so loud that the user (driver) feels uncomfortable. For this reason, a conventional hydraulic pressure control device for a brake system has been proposed in which the pulsation generated when the pump is driven is reduced. For example, the brake fluid pressure control device described in Patent Document 1 includes one pump in one hydraulic pressure circuit, and has a damper on the discharge side of the pump to reduce the pulsation of the brake fluid discharged from the pump. I have.

Special Table 2017-537020

The damper described in Patent Document 1 reduces the pulsation by temporarily accommodating the pulsation of the brake fluid discharged from the pump in a tubular, elastically deformable suppressing element. However, the brake fluid flowing into the restraining element does not contribute to the increase in the hydraulic pressure of the wheel cylinder that brakes the vehicle. Therefore, when the vehicle is braked by automatically pressurizing the brake fluid with a pump, until a desired braking force is obtained. There is a delay in the time. This means that if you want to brake the vehicle suddenly to avoid an imminent collision, collision avoidance or mitigation should be prioritized over noise, reducing the braking force rise time, depending on the vehicle conditions. It is desirable that the system is capable of doing so.

The present invention has been made in the context of the above-mentioned problems, and allows the brake fluid discharged from the pump to flow to the wheel cylinder according to the braking mode of the vehicle and the required braking force without using a damper. It is an object of the present invention to provide a brake fluid pressure control device that enables the above.

In the brake fluid pressure control device according to the present invention, a discharge pipeline in which the brake fluid boosted by the pump is discharged, a damper in which the brake fluid flows from the discharge pipeline, and the brake fluid flow into the damper. In a brake fluid pressure control device including a bypass valve that selectively guides a damper line through which brake fluid flows out or a bypass line that bypasses the damper, the bypass valve is the damper pipe. A piston having a damper line opening leading to the road and a bypass line opening leading to the bypass line is provided.

The brake hydraulic pressure control device according to the present invention includes a brake liquid including a bypass valve that guides the brake liquid that has flowed into the damper to selectively pass through either the damper pipe that flows out or the bypass pipe that bypasses the damper. In the pressure control device, the bypass valve includes a piston having a damper line opening leading to the damper line and a bypass line opening leading to the bypass line.
In other words, depending on the braking mode of the vehicle and the required braking force, the brake fluid pressurized by the pump and accompanied by pulsation is selectively selected as a damper pipe that reduces pulsation or a bypass pipe that bypasses the damper. It is possible to pass through and improve the degree of freedom in the arrangement of dampers, damper pipelines, and bypass pipelines.

It is a figure which shows an example of the structure of the brake fluid pressure control device which concerns on embodiment of this invention. It is a figure which shows the arrangement of the damper member of the conventional brake fluid pressure control device. It is a figure which shows the arrangement of the damper member of the brake fluid pressure control device which concerns on embodiment of this invention. It is a figure which shows the cross section of the bypass valve of the brake fluid pressure control device which concerns on embodiment of this invention. It is a figure explaining the movement of the bypass valve of the brake fluid pressure control device which concerns on embodiment of this invention. It is a figure explaining the movement of the bypass valve of the brake fluid pressure control device which concerns on embodiment of this invention.

Hereinafter, the hydraulic pressure control unit according to the present invention will be described with reference to the drawings.

In the following, a case where the brake system including the brake fluid pressure control device according to the present invention is mounted on a four-wheeled vehicle will be described, but the brake system including the brake fluid pressure control device according to the present invention will be described. It may be mounted on a vehicle other than a four-wheeled vehicle (two-wheeled vehicle, truck, bus, etc.). Further, the configuration, operation, etc. described below are examples, and the brake system including the hydraulic pressure control unit according to the present invention is not limited to such a configuration, operation, and the like. Further, in each figure, the same or similar members or parts are designated by the same reference numerals, or the reference numerals are omitted. Further, for the detailed structure, the illustration is simplified or omitted as appropriate.
<Structure explanation of brake system and brake fluid pressure control device>

The brake system shown in FIG. 1 is a diagram showing only the brake system for one wheel in the hydraulic circuit of the brake system for a four-wheeled vehicle. In FIG. 1, the brake system is applied to a brake system that amplifies the pedal effort of a driver's brake pedal and transmits it to a wheel cylinder without using a booster. However, the brake system may be an example of using a booster.

The brake fluid pressure control device 20 has four hydraulic circuits from the first to the fourth. Since the second to fourth hydraulic circuits have the same configuration as the first hydraulic circuit, they are omitted from FIG. Brake fluid is supplied from the master cylinder 13 to the wheel cylinders 14 of each of the four wheels via the first to fourth hydraulic circuits.

The first hydraulic circuit 30 includes a pump 45 driven by a motor 49. The first hydraulic circuit 30 includes an accumulator 25 and a damper 27.

The pump 45 is driven by the motor 49 to discharge the brake fluid. The drive of the motor 49 is controlled by the electronic control unit 10. The number of pumps 45 provided in the first hydraulic circuit 30 is not limited to one.

A first pressure sensor 17 is provided in the pipeline communicating with the master cylinder 13. The first pressure sensor 17 detects the internal pressure of the master cylinder 13.

A second pressure sensor 16 is provided in a pipeline communicating with the wheel cylinder 14 of the wheel hydraulic brake 15. The second pressure sensor 16 detects the internal pressure of the wheel cylinder 14.

The first hydraulic circuit 30 includes a plurality of electromagnetic control valves. The plurality of electromagnetic control valves are a circuit control valve 22 that is normally closed and can be linearly controlled, a suction control valve 26 that is normally closed and can be controlled on and off, a pressure booster valve 23 that is normally open and can be linearly controlled, and is normally closed. Includes a pressure reducing valve 24 that is controlled on and off by the mold.

The circuit control valve 22 is arranged in the flow path 32 connecting the master cylinder 13 and the discharge side of the pump 45. The circuit control valve 22 can be linearly controlled, and continuously adjusts the flow path area between the master cylinder 13 and the booster valve 23.

The suction control valve 26 is arranged in a pipeline 31 connecting the master cylinder 13 and the suction side of the pump 45. The suction control valve 26 communicates or shuts off between the master cylinder 13 and the suction side of the pump 45.

The pressure boosting valve 23 is arranged in a pipeline 33 connecting the circuit control valve 22 and the wheel cylinder 14. The pressure boosting valve 23 is linearly controllable, and continuously adjusts the flow rate of hydraulic oil from the master cylinder 13 and the circuit control valve 22 side to the wheel cylinder 14 side of the wheel hydraulic brake 15.

The pressure reducing valve 24 is arranged in a flow path 34 connecting the suction side of the pump 45 and the wheel cylinder 14. The pressure reducing valve 24 communicates or shuts off between the suction side of the pump 45 and the wheel cylinder 14. The pressure reducing valve 24 reduces the pressure by supplying the brake fluid supplied to the wheel cylinder 14 of the wheel hydraulic brake 15 to the accumulator 25 in the valve open state. By intermittently opening and closing the pressure reducing valve 24, the flow rate of the brake fluid flowing from the wheel cylinder 14 to the accumulator 25 can be adjusted.

The electronic control unit 10 performs the following hydraulic pressure control operations in addition to the well-known hydraulic pressure control operations (ABS control operation, ESP control operation, etc.), for example.
When the pressure boosting valve 23 is opened, the pressure reducing valve 24 is closed, the circuit control valve 22 is opened, the suction control valve 26 is closed, and the brake pedal 11 is operated, the brake lever switch BLS of the brake pedal 11 is operated. When it is detected that the hydraulic pressure of the wheel cylinder 14 is insufficient or the possibility of insufficient hydraulic pressure is detected from the detection signal and the detection signals of the pressure sensors 17 and 18 of the first hydraulic pressure circuit 30, the electronic control unit 10 controls the active pressure increase. Start operation.

In the active pressure boosting control operation, the electronic control unit 10 drives the motor 49 with the circuit control valve 22 closed, the suction control valve 26 open, and the pressure booster valve 23 open. This makes it possible for the brake fluid from the master cylinder 13 to flow to the wheel cylinder 14 via the pipeline 31 and the pipeline 33. At this time, the electronic control unit 10 limits the flow of the brake fluid from the wheel cylinder 14 to the accumulator 25 by keeping the pressure reducing valve 24 in the closed state. Further, the electronic control unit 10 adjusts the hydraulic pressure of the brake fluid of the wheel cylinder 14 by linearly controlling the pressure boosting valve 23.

When it is detected that the insufficient hydraulic pressure of the first hydraulic circuit 30 is resolved or avoided, the electronic control unit 10 opens the circuit control valve 22, closes the suction control valve 26, and drives the pump 45. By stopping, the active boost control operation is terminated.

Here, when the pump 45 is driven, the pulsation generated in the brake fluid may be transmitted to the wheel cylinder 14. Therefore, a hydraulic circuit is known in which a damper 27 is provided on the discharge side of the pump 45 to reduce the pulsation by temporarily accommodating the brake fluid accompanied by the pulsation in the damper. However, when it is necessary to immediately transmit the hydraulic pressure of the brake fluid to the wheel cylinder as in emergency braking, the brake fluid once stored in the damper does not flow to the wheel cylinder, so the rise of the vehicle braking force is delayed. There was a problem.
<Arrangement of conventional damper members>

The arrangement of the damper member and the flow of the brake fluid of the conventional brake fluid pressure control device will be described with reference to FIG.

The damper 27 is arranged on the discharge pipe 38 through which the brake fluid discharged from the pump 45 passes, and the throttle 28 and the check valve 29 are arranged downstream of the damper 27.

The pump 45 is configured as a plunger-type pump including two pump members (not shown), and these two pump members are driven by a motor 49 using an eccentric body. The pump member pumps the brake fluid through the discharge pipe 38 during operation, and at this time, causes a flow of the brake fluid accompanied by the hydraulic pressure. This brake fluid pulsates based on a plunger that acts alternately on the pump member. The pump 45 is arranged in the hydraulic housing 21 and pumps the pulsated brake fluid to the discharge pipe line.

The damper 27 is used to reduce the pulsation of the brake fluid, and therefore has a damping chamber inside. The brake fluid pumped by the pump once flows into the damping chamber. After that, the brake fluid that has flowed out of the damping chamber of the damper 27 flows out to the pipeline 33 via the throttle 28. The diaphragm 28 may be configured to be adjustable by a variable diaphragm action.
<Example of Arrangement of Damper Members According to the Present Invention>

The arrangement of the damper member and the flow of the brake fluid according to the present invention will be described with reference to FIG. As for the configuration similar to the arrangement of the conventional damper members, the same reference numerals are used in FIG. 3, and the same operations and functions as those described in FIG. 2 are obtained.

The arrangement of the damper members in FIG. 3 is different from the arrangement of FIG. 2, and the bypass pipe line 37 and the bypass valve 39 are provided. The bypass valve 39 can be controlled based on the hydraulic pressure P of the brake fluid with the hydraulic pressure generated by the pump 45. The bypass valve 39 is set so that the brake fluid discharged from the pump 45 passes through the damper pipe line 36 at a normal position (a position when there is no flow of the brake fluid accompanied by hydraulic pressure).

When the hydraulic pressure of the brake fluid passing through the bypass valve 39 is relatively low, for example, less than 20 bar, the bypass valve 39 remains in the normal position, so that the brake fluid passes through the damper pipe. On the other hand, when the hydraulic pressure of the brake fluid passing through the bypass valve 39 is relatively high, for example, 20 bar or more, the bypass valve 39 switches to a position where the brake fluid passes through the bypass pipe line 37. Therefore, the bypass valve 39 guides the brake fluid so as to bypass the damper 27 and the throttle 28 when the hydraulic pressure is relatively high.

Further, check valves 29 and 35 are provided downstream of the damper 27 provided in the damper pipe 36 and in the bypass pipe 37. The check valves 29 and 35 are configured to be closed when a hydraulic fluid pressure higher than that upstream is generated downstream of the check valves 29 and 35. When the check valves 29 and 35 are closed and the bypass valve 39 closes the damper pipeline 36, the damper 27 arranged downstream of the bypass valve 39 is used in the pipeline system of the brake fluid pressure control device. Completely fluidly separates from.
<Explanation of Cross-sectional View of Bypass Valve According to the Present Invention>

FIG. 4 shows a cross section of a bypass valve that can be controlled depending on the hydraulic pressure of the brake fluid.
The bypass valve 39 has a cup-shaped piston 391 and a spring 392.
One end of the spring 392 is coupled to the bottom of the piston 391, the other end is coupled to the end of the discharge line 38, and the spring 391 pushes the piston 391 in the direction opposite to the inflow direction of the brake fluid boosted by the pump. I'm urging. Further, a seal ring 395 is provided on the outer wall of the piston 391 so that the brake fluid does not flow back into the discharge pipe 38 through the outer wall of the piston.

In FIG. 4, the piston 391 is shown to be in the normal position, and a metal ring 396 is provided in the opening of the piston so that the piston 391 is held in the normal state. The spring 392 is a coiled spring in the embodiment, and when the hydraulic pressure of the brake fluid passing through the bypass valve 39 is relatively low, specifically less than 20 bar, the spring is in the position shown in FIG. The spring constant is set so that it is held at. The spring constant is adjusted in advance so that the spring 392 contracts when a predetermined force is applied to the piston due to the hydraulic pressure of the brake fluid.

The piston 391 further comprises a damper line opening 393 and a bypass line opening 394 lateral to the axis of the piston. In the embodiment, the damper line opening 393 and the bypass line opening 394 are arranged at positions symmetrical with respect to the axial direction of the piston 391, and are formed so that the piston can be easily processed. However, the arrangement of the damper pipe opening 393 and the bypass pipe opening 394 is not limited to this embodiment, and the arrangement may be appropriately changed according to the arrangement of the damper pipe and the bypass pipe. In the normal position, the damper line opening leads to the damper line 36, and the bypass line opening 394 is closed by the discharge line 38.

When the hydraulic pressure of the brake fluid passing through the bypass valve 39 becomes relatively high, specifically 20 bar or more, the piston 391 moves downward in FIG. 4 against the urging force of the spring 392. At this time, the damper line opening 393 is closed by the discharge line 38, and the bypass line opening 394 leads to the bypass line 37. The damper pipe opening 393 and the bypass pipe opening 394 have a stepped portion as shown in FIG. 4, and are configured to exert a drawing effect.
<Explanation of bypass valve movement>

FIG. 5 shows two valve positions of the bypass valve 39. FIG. 5 shows the normal position of the bypass valve or the position of the bypass valve when the brake fluid having a relatively low hydraulic pressure passes through the bypass valve. FIG. 6 shows the position of the bypass valve when the brake fluid having a relatively high hydraulic pressure passes through the bypass valve.

Inside the damper 27, an elastically deformable restraining element 271 in which the pulsating brake fluid is housed is provided. Below the damper 27, a damper pipe line 36 is provided so as to connect the discharge pipe line 38 and the damper 27. In the embodiment, the damper inflow pipe 36a that passes when the brake fluid flows from the discharge pipe 38 to the damper 27 and the damper outflow pipe 36b that passes when the brake fluid flows out from the damper 27 are the damper 27. It is provided substantially parallel to the axis of. Further, the bypass pipe 37 is connected to the discharge pipe 38 in parallel with the damper inflow pipe 36a and the damper outflow pipe 36b.

In the embodiment, the damper inflow pipe 36a and the bypass pipe 37 are arranged on opposite sides of the discharge pipe 38, and the bypass valve 39 is arranged so as to be inclined with respect to the damper inflow pipe 36a and the bypass pipe 37. Has been done.
Specifically, the angle formed by the sliding direction of the bypass valve and the damper inflow pipe 36a is an acute angle, and the angle formed by the sliding direction of the bypass valve and the bypass pipe 37 is set. They are arranged so that they have an acute angle.

The dashed arrow in FIG. 5 indicates the flow of the brake fluid when the brake fluid having a relatively low hydraulic pressure passes through the bypass valve. The brake fluid that has flowed into the piston 391 from the discharge pipe 38 is accommodated in the restraining element 271 of the damper 27 via the damper pipe opening 393 and the damper inflow pipe 36a. At this time, since the bypass pipe opening 394 is closed by the discharge pipe 38, the structure is such that the brake fluid does not flow out from the bypass pipe opening 394. After that, the brake fluid passes through the damper outflow pipe 36b having the throttle 28 and flows out to the pipe 33.

The broken line arrow in FIG. 6 indicates the flow of the brake fluid when the brake fluid with a relatively high hydraulic pressure passes through the bypass valve. The brake fluid that has flowed into the piston 391 from the discharge pipe 38 flows directly to the pipe 33 through the bypass pipe opening 394 and the bypass pipe 37. At this time, since the damper pipe opening 393 is closed by the discharge pipe, the brake fluid does not flow out through the damper pipe opening. Therefore, it is possible to bypass the damper 27 and the throttle 28 to reach the pipeline 33.
<Effect of Brake Fluid Pressure Control Device of the Present Invention>

The effect of the brake fluid pressure control device including the bypass valve and the bypass pipeline according to the present embodiment will be described.

The brake hydraulic pressure control device according to the present invention has a configuration in which the piston 391 of the bypass valve 39 has a damper pipe opening 393 leading to the damper pipe 36 and a bypass pipe opening 394 leading to the bypass pipe 37. Depending on the braking mode of the vehicle and the required braking force, it is possible to selectively pass through a damper pipe that reduces pulsation or a bypass pipe that bypasses the damper, and also a damper pipe and a bypass pipe. It is possible to improve the degree of freedom in arranging the roads.

In the brake hydraulic pressure control device according to the present invention, the bypass valve 39 is arranged so as to be inclined with respect to the damper line 36 or the bypass line 37, and the damper line opening 393 or the bypass line opening 394 is the piston 391. Since it is provided on the side of the shaft, the bypass valve 39, the damper pipe line 36, and the entire bypass pipe line can be housed compactly, and the sliding distance of the bypass valve can be reduced. ..

10 Electronic control unit, 20 Brake hydraulic pressure control device, 27 damper, 28 throttle, 36 damper line, 37 bypass line, 38 discharge line, 39 bypass valve, 45 pump, 391 piston, 392 spring, 393 damper line Opening, 394 bypass pipeline opening, 395 seal ring, 396 metal ring.

Claims (7)

A discharge line (38) through which the brake fluid boosted by the pump (45) is discharged, and
A damper (27) into which the brake fluid flows from the discharge pipe (38) and
The brake fluid is guided to selectively pass through either the damper pipe (36) through which the brake fluid that has flowed into the damper (27) flows out or the bypass pipe (37) that bypasses the damper (27). In a brake fluid pressure control device including a bypass valve (39)
The bypass valve (39) includes a piston (391) having a damper line opening (393) leading to the damper line (36) and a bypass line opening (394) leading to the bypass line (37). ,
Brake fluid pressure control device. The bypass valve (39) is arranged so as to be inclined with respect to the damper pipeline (36).
The brake fluid pressure control device according to claim 1. The bypass valve (39) is arranged at an angle with respect to the bypass line (37).
The brake fluid pressure control device according to claim 1 or 2. The damper pipeline opening (393) is provided laterally to the axis of the piston (391).
The brake fluid pressure control device according to any one of claims 1 to 3. The bypass line opening (394) is provided laterally to the axis of the piston (391).
The brake fluid pressure control device according to any one of claims 1 to 4. The brake fluid pressure according to any one of claims 1 to 5, wherein the damper line opening (393) and the bypass line opening (394) are located symmetrically with respect to the axis of the piston (391). Control device. The bypass valve (39) has a spring that urges the piston (391) in the direction opposite to the inflow direction of the brake fluid.
The brake fluid pressure control device according to any one of claims 1 to 6.

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