JPH08113127A - Hydraulic control mechanism - Google Patents

Abstract

PURPOSE: To provide the hydraulic control mechanism which can control the operating hydraulic pressure in its hydraulic pressure circuit in three stages, the pressure reduction, the pressure maintaining, and the pressure increasing, by providing only one solenoid pipe to each wheel. CONSTITUTION: The hydraulic control mechanisms are provided to the wheels of a vehicle, and control the braking forces of the wheels by producing a specific hydraulic pressure, and each mechanism has a valve mechanism 20 to produce from the first hydraulic pressure PM produced depending on the braking operation of a driver, to the second hudraulic pressure PW to control the braking force; and a solenoid valve 10 provided to control directly a control pressure PX to operate the valve mechanism 20, as well as to regulate the second hydraulic pressure PW; and the second hydraulic pressure PW is maintained almost at a constant pressure until the control pressure PX and the first hydraulic pressure PM are made almost the same pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control mechanism constituting a hydric unit for controlling operating hydraulic pressure in a hydraulic circuit such as an antilock brake.

[0002]

2. Description of the Related Art As a conventional hydraulic control mechanism of this type, for example, an FF vehicle will be described. Each wheel of a vehicle is provided with a solenoid valve and a mechanical valve having a function of keeping a constant boosting speed in a hydraulic circuit. It is known that each vehicle has four solenoid valves and four mechanical valves. With this hydraulic control mechanism, the number of electrically controlled solenoid valves can be reduced, and the drive circuits, harnesses, and other parts required for the ABS control unit can be reduced due to the reduced number of solenoid valves, resulting in a total system cost reduction. There is an effect that can be down.

Further, as another conventional example, two solenoid valves are provided on each wheel of an automobile so that the vehicle as a whole has eight solenoid valves.
It is known to be composed of individual solenoid valves.
In this hydraulic control mechanism, by controlling the open / closed state of the two solenoid valves, it is possible to perform three-step control of increasing / decreasing the operating hydraulic pressure and maintaining the hydraulic pressure, and there is an effect that more excellent brake control can be realized.

[0004]

By the way, among the hydraulic control mechanisms used in the anti-lock brakes of automobiles and the like, in the former conventional example, as shown by the dotted line in FIG. 5, the solenoid valve is used. Since the operating hydraulic pressure can be controlled only by a certain amount of pressure increase or decrease, if the vehicle has unstable vibrations during traveling, the operating hydraulic pressure will be maintained for a certain period to keep the vehicle running in the future. There is a high possibility that the hydraulic pressure cannot be controlled after it is seen, and at the same time, the operating hydraulic pressure is increased or decreased by mistake. In addition, there is a drawback that the deceleration load becomes insufficient because the hydraulic pressure cannot be rapidly increased in response to the sudden tendency of the wheel to recover from the lock.

Further, in the latter conventional example, by providing two solenoid valves for each wheel, it is possible to perform hydraulic control in three stages of pressure increase, pressure reduction and holding, but it is possible to control electrically. Since the number of solenoid valves used is twice that of the former, there is a drawback that the total cost of the system increases. Therefore, the present invention was proposed in order to solve the above-mentioned drawbacks of the prior art. The purpose of the present invention is to reduce the operating oil pressure in the hydraulic circuit by providing only one solenoid valve for each wheel. The present invention proposes a hydraulic control mechanism capable of controlling in three stages of holding, holding, and increasing pressure.

[0006]

In order to solve the above problems and to achieve the object, a hydraulic control mechanism of the present invention has the following constitution. That is, it is a hydraulic control mechanism that is provided on each wheel of the vehicle and that generates a predetermined hydraulic pressure to control the braking force of the wheel, and that is generated based on the brake operation of the driver.
And a hydraulic pressure generating means for generating a second hydraulic pressure for controlling the braking force from the hydraulic pressure and a control pressure for operating the hydraulic pressure generating means while directly controlling the second hydraulic pressure. A hydraulic pressure control means is provided, and the second hydraulic pressure is maintained at a substantially constant pressure until the control pressure and the first hydraulic pressure become substantially the same pressure.

Further, preferably, the oil passage to which the first hydraulic pressure is supplied and the oil passage to which the control pressure is supplied are communicated with each other through a throttle orifice. Further, preferably, the control pressure for operating the hydraulic pressure generating means is directly controlled by one electromagnetic solenoid valve. Further, preferably, when increasing the second hydraulic pressure, the solenoid valve is closed, and when decreasing the second hydraulic pressure, the solenoid valve is opened.

Preferably, the control pressure is the first pressure.
The holding time of the second hydraulic pressure can be arbitrarily set by repeating the operation of temporarily opening the solenoid valve within a time period until the hydraulic pressure becomes substantially the same as the hydraulic pressure. Also, preferably, the vehicle is equipped with an anti-lock brake system.

[0009]

Since the hydraulic control system of this embodiment is configured as described above, when the pressure reducing command is output to the solenoid valve (solenoid valve ON state), even if the master cylinder pressure is stored inside the hydric unit, Even if an intermediate pressure that is not pressure is generated and the pressure increase command is output next (solenoid valve off state), the wheel cylinder pressure is not increased until the intermediate pressure rises to the master cylinder pressure. It is held at the pressure at which it was released, and then increases rapidly, so the holding time can be controlled by turning the solenoid valve on and off, there is no need to install a new solenoid valve in the hydraulic circuit, and the braking performance is improved at a lower cost. It is possible to simplify the circuit configuration and reduce costs.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment applied to a four-wheel disc brake of an FF vehicle equipped with an antilock brake system will be described below as a preferred embodiment of the present invention with reference to the accompanying drawings. Hydraulic Circuit and Valve Configuration FIG. 1 is a sectional view showing the entire hydraulic control mechanism of an embodiment based on the present invention. Since this embodiment is an example applied to a four-wheel disc brake, it is assumed that the hydraulic control mechanism of this embodiment is provided on the front, rear, left and right wheels. Further, the control procedure of the anti-lock brake system adopts a commonly used method, and thus detailed description in this embodiment will be omitted.

In FIG. 1, when the driver depresses the brake pedal, a predetermined hydraulic pressure P _M is input from the master cylinder 1 to the main line 100. This main line 1
00 is connected to a control line 300 communicating with the wheel cylinder 2 via a port A ₁ . In addition, the main line 100 and the control line 300 are bypass lines 60.
Bypassed by 0. The bypass line 600 is provided with the throttle orifice 50, and the main line 100
Also, the hydraulic pressure in the control line 300 is configured not to change suddenly. Further, the main line 100 and the control line 300 are connected by a branch line 200. A check valve 60 is provided in the middle of the branch line 200, and the hydraulic pressure is input from the control line 300 to the main line 100 via the branch line 200 to prohibit the oil flow in the reverse direction. The check valve 60 has a function of returning the residual pressure remaining in the wheel cylinder 2 to the master cylinder 1 when the driver releases the brake pedal. Opening and closing port A1
It is controlled by the port opening / closing valve 41 biased by the spring 42. The port opening / closing valve 41 is normally in a state in which the port A1 is closed by the urging force of the spring 42, and is in an open state by pressing in the opposite direction to the urging force of the spring. The port opening / closing valve 41 is pressed by the valve mechanism 20 provided in the vicinity thereof. The control line 300 is connected to the wheel cylinder 2 and inputs the brake pressure P _W to the brake disc, which is regulated via the port opening / closing valve 41, to the wheel cylinder 2 and is connected to the solenoid valve 10 further downstream.

The solenoid valve 10 is a generally used electromagnetic solenoid. Solenoid valve 1
The actuator 13 of 0 is configured to move in the S1 direction by the magnetic force generated when a current flows through the solenoid 15. A port opening / closing valve 11 is provided at one end of the actuator 13, and opens / closes a port A2 of a reservoir line 400 leading to the oil reservoir 3 for drain. A nozzle 12 is provided at the other end of the actuator 13 to open and close the port A3 of the line 500 connected to the valve mechanism 20.

A line 500 connecting the solenoid valve 10 and the valve mechanism 20 is provided with a port opening / closing valve 30 biased by a spring 31. Normally, the port A3 is closed by the biasing force of the spring 31, and the actuator 13 is operated. Is slid and the nozzle 12 pushes the port opening / closing valve 30, so that the port A3 is opened and communicated with the valve mechanism 20. In this electromagnetic solenoid valve 10, the current flowing through the solenoid 15 and the port opening / closing valve 3
Since the pressing force of the nozzle 12 to 0, that is, the opening area of the port A3 is in a proportional relationship, the hydraulic pressure to the valve mechanism 20 input via the control line 300 can be continuously changed by increasing or decreasing the current. it can. Further, the actuator 13 is biased by the spring 14 and moves in the direction to close the port A2 by turning off the current to the solenoid.

The valve mechanism 20 is connected to the line 500 at the port A5 and has a piston 23 and a spring 24 therein. The spring 24 fixes the piston 23 at a predetermined position by its urging force. An O-ring 22 is provided on the side wall of the piston 23 to seal the side wall and the piston. The piston 23 is configured to slide in the S2 direction due to the pressure difference between the hydraulic pressure P _X in the oil chamber 27 communicating with the line 500 and the master cylinder pressure P _M of the line 100. The nozzle 2 is provided at one end of the piston 23.
6 is provided, and the port A1 is opened by pressing the port opening / closing valve 41. A port opening / closing valve 21 that opens / closes the port A5 is provided at the other end of the piston 23. The piston 23 is provided with a throttle orifice 28,
A small gap A _X is formed by the orifice 28, and the oil chamber 2 connected to the line 500 of the valve mechanism 20.
7 and the line 100 are connected. Also, the oil chamber 27
Is provided with a port A4 and is connected to the main line 100 and the branch line 700. Operating State Next, the operating principle of the hydraulic circuit of the present embodiment will be described with reference to FIGS.

The hydraulic circuit of this embodiment has one solenoid.
By electrically controlling the valve, boosting, depressurizing and holding
It realizes the three-step control of the following.
The operation principle in the state will be described. <Increase of pressure> FIG. 2 shows the oil pressure P to the wheel cylinder 2._WTo
The state in the hydraulic circuit at the time of increasing the pressure is shown. Figure 2 Smell
Turn off the power to the solenoid valve 10 and
Port A2 leading to the port 3 and the port leading to the valve mechanism 20.
Close port A3 (actuator 13 is S3 in FIG. 2)
Move to). In this state, the main line 100 and the oil chamber 2
7 is communicated with port A4 of line 700, so
The hydraulic pressure PM of the star cylinder 1 and the hydraulic chamber 2 of the valve mechanism 20
Oil pressure P in 7_XAnd are equal. Also, the piston 23
Since the spring 24 urges it in the direction of arrow S4, the port
A1 is opened, and master cylinder pressure P_MControl line 3
It is input to the wheel cylinder 2 via 00. This ho
With the increased pressure on the oil cylinder, the pedal force on the brake pedal is increased.
Is the brake pressure P_WAnd the brake is activated
You. <When decompressing> FIG. 3 shows the hydraulic pressure P to the wheel cylinder 2._WTo
The state in a hydraulic circuit at the time of decompressing is shown. Figure 3
Power on the solenoid valve 10
Port A2 leading to the port 3 and the port leading to the valve mechanism 20.
Valve A3 is opened (actuator 13 is S5 in FIG. 3).
Move in the direction). In this state, the reservoir pressure P_RIs almost zero
Since there is, the oil pressure P in the oil chamber 27_XAre ports A5, A3,
It is introduced into the reservoir 3 via A2. This hydraulic pressure P_XBut
Intermediate pressure becomes master cylinder pressure P_MWhen smaller
(P_X<P_M), The piston 23 strikes against the urging force of the spring 24.
Since it wins and moves in the direction of arrow S6, ports A1 and A
4, A5 is closed, wheel cylinder pressure P _WIs the control
Reservoir pressure P via in 300_RIs equal to (P_W=
P_R). In the depressurized state of this wheel cylinder,
Pressure P_WIs the reservoir pressure P_RNext to the wheel cylinder 2
Pressurized hydraulic pressure P_WIs the reservoir pressure P_RDecompressed to.
By the way, the hydraulic pressure P_XIs the master cylinder pressure P_MSmaller
When (P_X<P_M), The hydraulic pressure P in the main line 100_MIs
It gradually flows into the hydraulic chamber 27 through the orifice 28,
Hydraulic pressure P_X(Intermediate pressure) is the master cylinder pressure P_MBe equivalent to
The piston 23 moves in the direction opposite to the arrow S6 to try.
However, due to the movement of the piston 23, the port A5
Open the valve, pressure P in the oil chamber_XDecreases (P_R<P_X<P_MWhen
Therefore, the piston 23 moves again in the direction of the arrow S6.
The pressure is reduced. <At the time of holding> FIG. 4 shows the hydraulic pressure P to the wheel cylinder 2._WTo
The state in a hydraulic circuit at the time of keeping constant is shown. In Figure 4
Then, turn off the power to the solenoid valve 10 and
Communicates with the port A2 leading to the server 3 and the valve mechanism 20
Port A3 is closed (actuator 13 is S in FIG. 4).
Move in 8 directions). In this state, the brake pedal is depressed
Since it is still entrapped, the hydraulic pressure P of the master cylinder 1_MIs
Hydraulic pressure P in the hydraulic chamber 27 of the valve mechanism 20_X(Intermediate pressure)
Becomes larger (P_X<P_M), Oil in the main line 100
Pressure P_MThrough the orifice 28 to the hydraulic chamber 27 little by little
Inflow and intermediate pressure oil pressure P_XIs the master cylinder pressure P_MEquivalent to
The piston 23 moves in the direction of arrow S7 until
Port A1 is closed. Port A1 and port A2 are closed
Since it is valved, the main line 100 to the control line 3
The oil flowing into 00 is the oil in the bypass line 600.
Only minute flow through the fis 50 will
Pressure P_WIs held substantially constant. Keep this hold
In order to do this, as shown in FIG. 5 and FIG.
Oil pressure P_MIs oil in the hydraulic chamber 27 of the valve mechanism 20.
Pressure P_XGreater state (P_X<P_M) To hydraulic pressure P_XIs the master
Cylinder pressure P_MWithin the time T until it becomes equivalent to
This solenoid should be turned on (Fig. 4).
(Movement in the direction of S9) is repeated at predetermined intervals T for a long time
(For example, time T1) can be held. Modifications The present invention can be modified in various ways without departing from the spirit thereof.
Is.

For example, in the above embodiment, the four-wheel disc brake of the FF vehicle has been described, but the invention is not limited to the above embodiment as long as the vehicle can be equipped with the anti-lock brake device, and it is controlled by the hydraulic circuit. The device can be applied not only to anti-lock brakes but also to limited slip differentials and the like.

[0017]

As described above, according to the hydraulic control mechanism of the present invention, when the pressure reducing command is output to the solenoid valve (solenoid valve ON state), even if the master cylinder pressure is present inside the hydric unit, the reservoir Even if an intermediate pressure that is not pressure is generated and the pressure increase command is output next (solenoid valve off state), the wheel cylinder pressure remains at that intermediate pressure until the intermediate pressure rises to the master cylinder pressure. Since it is held and then rapidly increases in pressure, the holding time can be controlled by turning on and off the solenoid valve, there is no need to install a new solenoid valve in the hydraulic circuit, it is cheaper and the braking performance is further improved, the circuit configuration is simplified and the cost is reduced. Can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire hydraulic control mechanism according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state in a hydraulic circuit when increasing hydraulic pressure to a wheel cylinder.

FIG. 3 is a diagram showing a state in a hydraulic circuit when the hydraulic pressure to a wheel cylinder is reduced.

FIG. 4 shows a state in the hydraulic circuit when the hydraulic pressure to the wheel cylinder is kept constant.

FIG. 5 is a timing chart showing an energized state of a solenoid and a change in hydraulic pressure to a wheel cylinder.

FIG. 6 is a timing chart showing energization control of a solenoid and a hydraulic pressure change to a wheel cylinder in a holding state.

[Explanation of symbols]

 1 ... Master cylinder 2 ... Wheel cylinder 3 ... Reservoir 10 ... Solenoid valve 11 ... Port opening / closing valve 15 ... Solenoid 20 ... Valve mechanism 21 ... Port opening / closing valve 22 ... O-ring 23 ... Piston 27 ... Hydraulic chamber 28, 50, 60 ... Throttle Orifice

Claims (6)

[Claims] 1. A hydraulic control mechanism which is provided on each wheel of a vehicle and which controls a braking force of the wheel by generating a predetermined hydraulic pressure, the first hydraulic pressure being generated based on a brake operation of a driver. Hydraulic pressure generating means for generating a second hydraulic pressure for controlling the braking force, and hydraulic pressure control means for adjusting the second hydraulic pressure and directly controlling a control pressure for operating the hydraulic pressure generating means. And a second hydraulic pressure is maintained at a substantially constant pressure until the control pressure and the first hydraulic pressure become substantially the same pressure. 2. The hydraulic control according to claim 1, wherein the oil passage to which the first hydraulic pressure is supplied and the oil passage to which the control pressure is supplied are communicated with each other through a throttle orifice. mechanism. 3. The hydraulic control mechanism according to claim 1, wherein the control pressure for operating the hydraulic pressure generating means is directly controlled by one electromagnetic solenoid valve. 4. The solenoid valve is closed when increasing the second hydraulic pressure, and the solenoid valve is opened when decreasing the second hydraulic pressure. Item 4. The hydraulic control mechanism according to Item 3. 5. The holding time of the second hydraulic pressure is changed by repeating an operation of temporarily opening the solenoid valve within a time period until the control pressure becomes substantially the same as the first hydraulic pressure. The hydraulic control mechanism according to claim 3, wherein the hydraulic control mechanism can be set arbitrarily. 6. The brake hydraulic control mechanism according to claim 1, wherein the vehicle is equipped with an anti-lock brake system.