JP4137226B2 - Hydraulic brake device for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of this application relates to a hydraulic brake device for a vehicle configured to supply a wheel brake with a hydraulic pressure higher than the hydraulic pressure of a master cylinder during vehicle braking.
[0002]
[Prior art]
This type of vehicle hydraulic brake device is already known, and is described in, for example, Japanese Patent Application Laid-Open No. 8-230634. The hydraulic brake device includes a wheel brake for applying a braking force having a magnitude corresponding to the magnitude of the supplied hydraulic pressure to the wheel, a brake fluid reservoir, and brake fluid supplied from the brake fluid reservoir as a brake pedal. A master cylinder that boosts the pressure by stepping on the brake and supplies it to the wheel brake; a hydraulic pump driven by an electric motor that boosts the brake fluid supplied from the brake fluid reservoir via the master cylinder and supplies the brake to the wheel brake; Brake fluid is supplied from the master cylinder to the suction side of the hydraulic pump, and a first open / close solenoid valve interposed in the first passage for supplying boosted brake fluid to the wheel brake without passing through the hydraulic pump. And a second open / close solenoid valve interposed in the second passage.
[0003]
Normally, the second open / close solenoid valve is closed and the first open / close solenoid valve is opened. Therefore, when the driver of the vehicle depresses the brake pedal, the master cylinder boosts the brake fluid supplied from the reservoir to the first. The hydraulic pressure in the wheel brake is increased or decreased according to the increase or decrease in the pedal effort of the brake pedal.
[0004]
Further, when the hydraulic pressure of the wheel brake is increased higher than the hydraulic pressure generated by the master cylinder under the state where the brake pedal is depressed as described above, the first opening / closing solenoid valve is closed and the second opening / closing solenoid valve is closed. The solenoid valve is opened and the hydraulic pump is activated. The hydraulic pump further boosts the boosted brake fluid supplied from the master cylinder via the second open / close solenoid valve, and supplies the boosted brake fluid to the wheel brake via the third open / close solenoid valve. The hydraulic pressure of the wheel brake at this time can be adjusted to an arbitrary hydraulic pressure by controlling the opening / closing of the first opening / closing electromagnetic valve by duty control or by controlling the rotation speed of the hydraulic pump by duty control. However, in general, the hydraulic pressure is adjusted to a hydraulic pressure amplified at a constant amplification factor with respect to the hydraulic pressure of the master cylinder.
[0005]
[Problems to be solved by the invention]
However, when the duty control of the first open / close solenoid valve is performed, hydraulic pressure vibration is generated, abnormal noise and vibration of the brake pedal are generated, which causes the driver to feel uncomfortable and leads to deterioration of the durability performance of the open / close solenoid valve. In addition, since the flow rate passing through the open / close solenoid valve changes due to the pressure difference between the wheel brake and the master cylinder, the control of the open / close solenoid valve is complicated, or a wheel brake hydraulic pressure sensor is required. On the other hand, when the rotational speed of the hydraulic pump is controlled, there is a problem that the control is complicated, or a heat generation countermeasure is required for the drive circuit of the electric motor that drives the hydraulic pump.
[0006]
The invention of this application aims to solve the above-mentioned problems.
[0007]
[Means for Solving the Problems]
The invention of claim 1 of the present application provides a wheel brake for applying a braking force having a magnitude corresponding to the magnitude of the supplied hydraulic pressure to the wheel, a brake fluid reservoir, and a brake fluid supplied from the brake fluid reservoir. A master cylinder that boosts pressure by depressing a brake pedal and supplies the wheel brake, and a hydraulic pump that boosts brake fluid supplied from the brake fluid reservoir via the master cylinder and supplies the brake fluid to the wheel brake; First valve means interposed in the first passage for opening and closing a first passage for supplying boosted brake fluid from the master cylinder to the wheel brake without passing through the hydraulic pump; and the master A second passage for opening and closing a second passage for supplying brake fluid from the cylinder to the suction side of the hydraulic pump is interposed in the second passage. In the vehicle hydraulic brake device including the second valve means, the first valve means is disposed in parallel with the first valve means in a direction from the downstream side to the upstream side. A relief valve that allows only a flow, and has a relief valve configured to increase or decrease in response to an increase or decrease in the upstream hydraulic pressure of the first valve means. The vehicle hydraulic brake device is characterized.
[0008]
A second aspect of the present invention is the vehicle hydraulic brake device according to the first aspect, wherein the relief valve receives the hydraulic pressure on the upstream side of the first valve means and closes the valve. A hydraulic brake device for a vehicle, comprising a piston for increasing the amount of bending of the spring.
[0009]
In order to perform anti-lock control or the like, a third passage for supplying the brake fluid discharged from the hydraulic pump between the first valve means of the first passage and the wheel brake; A third valve means interposed between a connection portion of the first passage with the third passage and the wheel brake, and opens and closes the first passage; It is preferable to further include a fourth passage for allowing the pressure pump to flow out to the suction side, and a fourth valve means interposed in the fourth passage for opening and closing the fourth passage.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a two-system hydraulic brake device for a vehicle according to the invention of this application. The configuration of one system for applying a braking force to the front left wheel FL and the rear right wheel RR and the front right wheel and the rear left wheel (not shown) are shown. Since the configuration of the other system for applying the braking force to the same is the same, only one hydraulic system is shown, and the other system is not shown. One system of the two-system hydraulic brake device 10 for a vehicle includes wheel brakes 11 and 12 that apply a braking force of a magnitude corresponding to the magnitude of the supplied hydraulic pressure to the wheels FL and RR, a brake fluid reservoir 13, The brake fluid supplied from the brake fluid reservoir 13 is boosted by depressing the brake pedal 14 and supplied to the wheel brakes 11 and 12 (hereinafter simply referred to as “master cylinder”) 15. A hydraulic pump 16 that boosts the brake fluid supplied through the cylinder 15 and supplies the brakes 11 and 12 is provided. Between the brake pedal 14 and the master cylinder 15, a booster (a booster) 17 is provided for amplifying the pedal force applied to the brake pedal 14 and inputting it to the master cylinder 15. The hydraulic pump 16 has only a piston pump action and is driven by an electric motor (not shown).
[0011]
A normally open on-off solenoid valve 19 at the 2-port 2 position is interposed in the passage 18 for supplying the pressurized brake fluid from the master cylinder 15 to the wheel brakes 11 and 12 without going through the hydraulic pump 16. The passage 18 corresponds to the first passage, and the open / close electromagnetic valve 19 corresponds to the first valve means.
[0012]
In the passage 20 for supplying brake fluid from the master cylinder 15 to the suction side of the hydraulic pump 16, a normally closed on-off electromagnetic valve 21 at the 2-port 2 position is interposed. The passage 21 corresponds to the second passage, and the open / close electromagnetic valve 21 corresponds to the second valve means.
[0013]
In order to reduce hydraulic pulsation on the discharge side of the hydraulic pump 16, the passage 22 supplying brake fluid discharged from the hydraulic pump 16 between the open / close solenoid valve 19 of the passage 18 and the wheel brakes 11 and 12 is mutually connected. A series damper chamber 23 and orifice 24 are interposed. The passage 22 corresponds to the third passage.
[0014]
Between the connecting portion of the passage 18 to the passage 22 and the wheel brakes 11 and 12, normally opened and closed electromagnetic valves 25 and 26 at 2 ports and 2 positions are interposed, respectively, so that the brake fluid in the wheel brake 11 is fluid pressure. Normally closed on-off solenoid valves 29 and 30 at the 2-port 2 position are interposed in the passage 27 for flowing out to the suction side of the pump 18 and the passage 28 for flowing brake fluid in the wheel brake 12 to the passage 27, respectively.
[0015]
The open / close electromagnetic valves 25 and 26 correspond to the third valve means, the passages 27 and 28 correspond to the fourth passage, and the open / close electromagnetic valves 29 and 30 correspond to the fourth valve means.
[0016]
A check valve 31 for blocking the flow of brake fluid from the passage 20 to the passage 27 is interposed in the passage 27 and a low pressure accumulator 32 for temporarily storing the brake fluid flowing out from the wheel brakes 11 and 12 is connected. ing.
[0017]
A relief valve 33 and a check valve 34 are connected to the passage 18 so as to be in parallel with the open / close electromagnetic valve 19, and check valves 35 and 36 are connected in parallel with the open / close electromagnetic valves 25 and 26, respectively. It is connected to become. The check valve 34 can supply hydraulic pressure from the upstream side (master cylinder side) to the downstream side (wheel brake side) of the open / close solenoid valve 19 with the open / close solenoid valve 19 closed. Under the closed state of the valve 25, the hydraulic pressure can be discharged from the downstream side to the upstream side of the open / close electromagnetic valve 25, and the check valve 36 is connected from the downstream side to the upstream side of the open / close electromagnetic valve 26 under the closed state of the open / close electromagnetic valve 26. The hydraulic pressure can be discharged.
[0018]
2 to 5 show the configuration and operation of the relief valve 33. As shown in FIGS. 2 to 4, the relief valve 33 is a valve body 33B for opening and closing the inlet 33A1 in a body 33A having an inlet 33A1 and an outlet 33A2, and a valve closing valve for biasing the valve body 33B in the closing direction. Spring 33C, stepped piston 33D for increasing / decreasing the amount of deflection of the valve closing spring 33C in accordance with the increase / decrease of the hydraulic pressure upstream of the open / close solenoid valve 19 (hydraulic pressure of the master cylinder), and the stepped piston A return spring 33E that energizes 33D in a direction in which the amount of bending of the valve closing spring 33C decreases is accommodated. The left end surface of the large diameter portion of the stepped piston 33D is exposed to the air chamber 33F, the liquid chamber 33G where the right both end surfaces of the stepped piston 33D are exposed communicates with the outlet 33A2, and the left end surface of the stepped piston 33D is exposed. The liquid chamber 33H communicates with the outlet 33A2 via an orifice 33I for suppressing axial vibration of the valve body 33B and the stepped piston 33D.
[0019]
The state of FIG. 2 shows a state when the hydraulic pressure at the outlet 33A2 is the hydraulic pressure P1 of FIG. 5, and the hydraulic pressure at the outlet 33A2 is changed from the large-diameter cross-sectional area S1 to the small-diameter cross-sectional area of the stepped piston 33D. The sum of the force that urges the stepped piston 33D leftward in FIG. 2 by acting on the area minus S2 and the force of the return spring 33E and the force of the valve closing spring 33C is the stepped piston 33D. Is balanced at a position where the right end of the body abuts the body 33A. Accordingly, the length of the valve closing spring 33C is the maximum L0, that is, the amount of bending of the valve closing spring 33C is minimized, the force of the valve closing spring 33C is minimized, and the force of the valve closing spring 33C is reduced to the inlet 33A1. The relief pressure obtained by dividing the hydraulic pressure by the area S3 acting on the valve body 33B is almost zero.
[0020]
As the hydraulic pressure at the outlet 33A2 rises from the hydraulic pressure P1 to P2 in FIG. 5, the stepped piston 33D slides to the left as shown in FIG. 3, and the length of the valve closing spring 33C increases. L1 is smaller than L0, that is, the amount of bending of the valve closing spring 33C increases, and the relief pressure increases. When the hydraulic pressure at the outlet 33A2 reaches the hydraulic pressure P2 in FIG. 6, the left end of the large diameter portion of the stepped piston 33D comes into contact with the body 33A as shown in FIG. 4, and the length of the valve closing spring 33C Becomes the minimum L2, that is, the amount of bending of the valve closing spring 33C becomes the maximum, and the relief pressure becomes the maximum.
[0021]
The electrical control device 37 that controls the operation of the electric motor that drives the open / close solenoid valves 19, 21, 25, 26, 29, and 30 and the hydraulic pump 16 includes a detection output of a sensor 38 that detects the rotational speed of the wheel FL, The detection force of the sensor 39 that detects the rotational speed of the wheel RR, the detection output of the sensor 40 that detects the depression force of the brake pedal 14, and the like are input. The electrical control device 37 performs known antilock control, traction control, brake servo control, and the like based on the detection outputs of the sensors 38 to 40. In normal times, the open / close solenoid valves 19, 21, 25, 26, Both 29 and 30 and the motor are deactivated as shown in FIG.
[0022]
In the state of FIG. 1, when the driver depresses the brake pedal 14 to stop the traveling vehicle, the booster 17 is activated to activate the master cylinder 15, and the master cylinder 15 is supplied from the brake fluid reservoir 13. The brake fluid is boosted and supplied to the wheel brakes 11 and 12 via the passage 18, and the wheel brakes 11 and 12 have a braking force having a magnitude corresponding to the magnitude of the hydraulic pressure supplied to the wheels FL and RR, respectively. Add When the depressing force of the brake pedal 14 is increased beyond the level at which the hydraulic pressure of the master cylinder 14 becomes the hydraulic pressure P1 in FIG. 5, the electrical control device 37 activates the open / close solenoid valves 19 and 21. The electric motor that drives the hydraulic pump 16 is operated. As a result, the hydraulic pump 16 boosts the brake fluid supplied from the master cylinder 15 via the passage 20 and discharges it to the downstream side of the open / close solenoid valve 19, so that the hydraulic pressure of the wheel brakes 11 and 12 is increased by the master cylinder 15. Higher than the hydraulic pressure. In this case, the hydraulic pressure level of the wheel brakes 11 and 12 is controlled by the relief valve 33. 6 shows the master cylinder 15 when the hydraulic pressure of the master cylinder 15 is increased or decreased so that the relief valve 33 changes from the state shown in FIG. 2 to the state shown in FIG. 4 through the state shown in FIG. The relationship between the hydraulic pressure (M / C hydraulic pressure) and the wheel brakes 11 and 12 (W / B hydraulic pressure) is shown. When the hydraulic pressure in the master cylinder 15 is equal to or lower than the hydraulic pressure P1 in FIG. 5, the hydraulic pressure supplied to the wheel brakes 11 and 12 corresponds to the input of the master cylinder 15, that is, the output of the booster 17.
[0023]
At the time of vehicle braking, the braking force applied to the wheels FL and RR is excessive with respect to the frictional force between each wheel and the road surface, and the slip amount of one of the wheels FL and RR, for example, the wheel FL is excessive. When the tendency, that is, the tendency of the wheel RL to lock, appears, the electrical control device 37 detects this phenomenon and activates the open / close solenoid valves 25 and 29 and the motor. The hydraulic pressure supply from the master cylinder 15 to the wheel brake 11 is cut off by the operation of the open / close electromagnetic valve 25, and the boosted brake fluid in the wheel brake 11 is discharged to the passage 27 by the operation of the open / close electromagnetic valve 29. As the hydraulic pressure is reduced, the braking force applied to the wheel FL decreases, and the slip amount of the wheel FL decreases. The brake fluid that has flowed out into the passage 27 is returned to the passage 18 by the hydraulic pump 16 that is operated by the electric motor, and the amount of the outflow from the wheel brake 11 to the passage 27 is returned to the passage 18 from the passage 27 by the operation of the hydraulic pump 16. The brake fluid amount obtained by subtracting the flow rate is temporarily stored in the low pressure accumulator 32, and when the inflow amount to the passage 27 is smaller than the reflux amount, the brake fluid in the low pressure accumulator 32 is returned to the passage 18 by the hydraulic pump 16. The When the tendency of the wheel FL to be locked and the tendency of the slip amount of the wheel FL to become small due to the depressurization of the wheel brake 11 appears, this phenomenon is detected by the electrical control device 37 and the on-off solenoid valves 25 and 29 are deactivated. Alternatively, the switching solenoid valve 25 is repeatedly deactivated and activated while the switching solenoid valve 29 is deactivated. As a result, the boosted brake fluid supplied from the master cylinder 15 and the hydraulic pump 16 to the passage 18 is continuously or intermittently supplied to the wheel 11, and the hydraulic pressure in the wheel brake 11 is continuously or stepwise. The braking force applied to the wheel FL increases, and the slip amount of the wheel FL increases. In this way, the hydraulic pressure in the wheel brake 11 is automatically adjusted according to the degree of slippage of the wheel FL, so that a maximum braking force that does not lock the wheel is applied to the wheel FL.
[0024]
As with the automatic adjustment of the hydraulic pressure in the wheel brake 11, the hydraulic pressure in the wheel brake 12 at the time of vehicle braking also activates / deactivates the open / close solenoid valves 26, 30 and the electric motor according to the degree of slip amount of the wheel RR. Thus, a maximum braking force that does not lock the wheel is applied to the wheel RR.
[0025]
【The invention's effect】
As described above, the hydraulic brake device for a vehicle according to the invention of this application is found in the conventional device because the amplification ratio of the hydraulic pressure of the wheel brake to the hydraulic pressure of the master cylinder is set by the relief valve. Such problems are resolved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a vehicular dual-system hydraulic brake device according to the invention of this application.
FIG. 2 is a diagram showing the configuration and operation of the relief valve in FIG. 1;
3 is a diagram showing the configuration and operation of the relief valve in FIG. 1. FIG.
4 is a diagram showing the configuration and action of the relief valve in FIG. 1. FIG.
FIG. 5 is a diagram showing the relationship between the hydraulic pressure of the machine cylinder and the hydraulic pressure of the wheel brake.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Two-system hydraulic brake device FL, RR for vehicles ... Wheel 11, 12 ... Wheel brake 13 ... Brake fluid reservoir 14 ... Brake pedal 15 ... Master cylinder 16 ...・ Hydraulic pump 18 ... passage 19 ... open / close solenoid valve 20 ... passage 21 ... open / close solenoid valve 33 ... relief valve

Claims (2)

The wheel brake for applying a braking force of a magnitude corresponding to the magnitude of the supplied hydraulic pressure to the wheel, the brake fluid reservoir, and the brake fluid supplied from the brake fluid reservoir are boosted by depressing the brake pedal, and A master cylinder that supplies the wheel brake, a hydraulic pump that boosts the brake fluid supplied from the brake fluid reservoir via the master cylinder and supplies the brake fluid to the wheel brake, and a master cylinder that passes through the hydraulic pump. First valve means interposed in the first passage for opening and closing a first passage for supplying boosted brake fluid to the wheel brake, and from the master cylinder to the suction side of the hydraulic pump. Vehicle having second valve means interposed in the second passage for opening and closing the second passage for supplying brake fluid In the hydraulic brake device, the relief valve is interposed in parallel with the first valve means in the first passage and allows only a flow from the downstream side to the upstream side of the first valve means, A vehicular hydraulic brake device comprising a relief valve configured to increase or decrease the relief pressure corresponding to the increase or decrease of the upstream hydraulic pressure of the first valve means. 2. The vehicle hydraulic brake device according to claim 1, wherein the relief valve includes a piston that receives the fluid pressure on the upstream side of the first valve means to increase a deflection amount of the valve closing spring. 3. A hydraulic brake device for a vehicle, comprising:

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