JPH01314655A - Hydraulic pressure controlling method using solenoid valve - Google Patents

Abstract

PURPOSE:To make it possible to control liquid pressure by means of a single solenoid valve so as to lower the cost of an anti-lock controller and the like, by connecting a pressure reduction passage which allows pressure liquid to flow therethrough away to a main liquid passage leading to a pressure liquid supplied portion, and interposing a solenoid valve controlled with duty ratio on the lower portion of this pressure reduction passage. CONSTITUTION:In a brake hydraulic pressure controller equipped with an anti-lock and traction controller, a pressure reduction passage 8 which allows pressure liquid inside the pressure liquid supplied portion 1 (a wheel cylinder, etc.) of a wheel braking device to flow therethrough away to a reserver 7 is branchingly connected to a main liquid passage 3 which supplies pressure liquid generated in a liquid pressure source 10 (i.e. a tandem type master cylinder, etc.) to the pressure liquid supplied portion 1. And also a solenoid valve 9 is interposed in a certain place within the area from the branch point of this pressure reduction passage 8 and the main liquid passage 3 to the lower side of the pressure reduction passage 8. And liquid pressure of the pressure liquid supplied portion 1 is controlled by varying the duty ratio of pulse signals applied to the solenoid valve 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of controlling hydraulic pressure using a solenoid valve, and particularly to a method of controlling brake hydraulic pressure by controlling the drive of a solenoid valve used in an anti-lock control device or a traction control device. I'm concerned.

[Conventional technology]

Conventionally, in brake fluid pressure control devices such as anti-lock control devices and brake control devices, in order to increase or decrease brake fluid pressure, a normally open build valve and a normally closed decay valve are usually separated or 3-way. Prepared as a valve,
The basic method is to pressurize via a build valve, and to reduce pressure by closing the build valve and opening the decay valve to absorb pressurized liquid into the reservoir.

[Problem to be solved by the invention]

However, this method requires two valves, a build valve and a decay valve, which is uneconomical, and
Even if each valve were integrated into 30,000 valves, two valve parts would be required to select the pressurization route and the pressure reduction route, resulting in a complicated structure.

In addition, conventional valves have only two options: open or close, and cannot adjust the flow rate of the pressure fluid, making it impossible to finely adjust the pressure increase or decrease of the brake fluid pressure.

The present invention was developed in view of the above-mentioned problems, and its technical problem is to enable the adjustment of fluid pressure with a single valve, and also to enable delicate adjustment of the pressure. be.

[Means to solve the problem]

In order to solve the above problems, the present invention takes the following measures.

That is, the present invention connects a main fluid path connecting a hydraulic pressure source and a pressurized liquid supplied section that receives pressure liquid from this hydraulic pressure source with a depressurization path that releases the pressure liquid in the pressurized liquid supplied section. A solenoid valve that is turned on and off by applying a pulse signal is inserted at an arbitrary position from the intersection of the depressurization path and the main liquid path to the downstream side of the depressurization path, and the duty of the pulse signal applied to this solenoid valve is
This is a hydraulic pressure control method using an electromagnetic valve, which is characterized in that the hydraulic pressure of a pressurized liquid supplied part is controlled by changing the ratio.

[Effect]

For ease of understanding, the operation of the present invention will be explained with reference to FIG.

It is now assumed that pressure fluid is being supplied from the hydraulic pressure source 10 through the main fluid path 3. In the present invention, when the solenoid valve 9 is a normally closed type, the opening operation time/closing operation time of the solenoid valve 9 is proportional to the duty ratio of the pulse signal, and when the solenoid valve 9 is a normally open type, The closing operation time/opening operation time of the solenoid valve 9 is proportional to the duty ratio of the pulse signal, and as the ratio of the closing operation time increases, the pressure supplied from the hydraulic pressure source 10 decreases from the pressure reducing path 8. 7, the escape ratio decreases, and the amount of pressurized fluid supplied to the pressurized fluid supplied portion 1 increases, causing it to be pressurized, and when the ratio of the closing operation time decreases, the pressure is reduced by the opposite effect.

〔Example〕

Hereinafter, an example in which the present invention is applied to a brake fluid pressure control device with an anti-lock and traction control tall device installed in a so-called front-wheel drive vehicle will be described with reference to FIG.

First, from one hydraulic pressure generating chamber of the tandem type mask cylinder (M/C) to the wheel cylinder (W/C) side of the left front axle brake device as the pressurized liquid supplied part 1 and the right side through the main gate valve 2a. Wheel cylinder of rear wheel brake system (
A main liquid path 3a is provided which branches to the W/C side. Then, check the wheel cylinder (W) of the right rear wheel brake device.
A normally open cut valve 4a and a blotting valve (PCV) are sequentially inserted into the main liquid path 3a+ branching to the /C) side. A return path 6a is connected from the cut valve 4a and the proportioning valve (PCV) to the mask cylinder (M/C) via the check valve 5a.

In addition, the wheel cylinder (W/C) of the right rear wheel brake system
In the middle of the main liquid path 3a1 branched to the side, there is a pressure reducing path 8a leading to the reservoir 7 on the upstream side of the cut valve 4a.
is connected, and a normally closed decay valve 9a serving as a solenoid valve 9 according to the present invention is inserted in the middle of this pressure reducing path 8a. A pump 10a corresponding to the hydraulic pressure source 1o in the present invention is connected to the reservoir 7, and the pump 1a is connected to a wheel cylinder (W/C) of the left front wheel brake system via a check valve 1'1a. ) Main liquid path 3a between
It is also connected to the reservoir 7 via the relief valve 12a.

The same hydraulic pressure circuit as above is connected to the other hydraulic pressure generating chamber of the tandem mask cylinder (M/C), the wheel cylinder (W/C) of the right front wheel brake device, and the left rear wheel brake. It is provided between the foil cylinder (W/C) of the device. In addition, the same parts are indicated by the same numbers with a symbol.

On the other hand, in response to a signal from a wheel speed sensor (S) provided on each wheel, a risk of wheel locking or a wheel slip state is detected, and based on the detection results, the main gate valve 2a, cut valve 4a, and decay valve A microcomputer-based control unit (ECU) is provided to control the opening and closing of the pump 9a or to start and stop the pump.

A pulse generator 13 is provided between this control unit (ECU) and the Decay valve 9a, and generates a pulse signal to open and close the Decay valve 9a. The ratio is continuously variable in the range of 0 to 100%.

In this case, the decay valve 9a detects the period 6 of the pulse signal. The mode of operation changes as the wave number changes.

When the frequency of the pulse signal is equal to or higher than the response limit frequency of the decay valve 9a, the valve gi of the decay valve 9a
PJ (V) does not attach or detach from the valve seat following a pulse signal, but its stroke away from the valve seat is determined according to the integral value of the supplied power determined by the duty ratio of the pulse signal, and - [Depending on the degree of coke, the distance between the valve portion (V) and the valve seat is adjusted to be wide or narrow, and as a result, the area of the liquid path toward the pressure reducing path 8a is determined. In other words, the liquid path area changes in size in proportion to the duty ratio of the pulse signal. Therefore, the smaller the area of the liquid path toward the pressure reducing path 8a, the smaller the foil cylinder (
1,1/C) is applied, and vice versa, the liquid pressure is reduced.

In addition, when the frequency of the pulse signal is lower than the response limit frequency of the Decay valve 9a, the valve gA (V) of the Decay valve 9a follows the pulse signal and is attached to and detached from the valve seat, so the pulse signal has the same duty ratio as the pulse signal. The opening and closing are repeated at the time of the duty ratio of the signal - 7=, and as a result, the integral value of the flow rate of the pressure fluid per unit time changes in magnitude, so when this value is small, the foil cylinder as the hydraulic pressure supplied part 1 ( W/C)
The liquid pressure is increased, and when it increases, it is reduced. However, in this mode of operation, since the valve portion (V) is attached to and removed from the valve seat, pulsations occur in the pressure liquid flow.

Next, the operation of the brake fluid pressure control device described above will be explained.

First, anti-lock control will be explained.

Assume that the control device (ECtJ) receives the axle speed signal and determines that ``there is a risk of wheel lock on the left front wheel.'' Then, the main gate valve 2a is closed by a command from the control device (ECU), and the pump 10a is started.

First, the duty ratio of the pulse signal is set high and applied to the decay valve 9a. Then, the flow rate of the pressurized fluid passing through the decay valve 9a and escaping to the reservoir 7 increases, the fluid pressure in the foil cylinder (IJ/C) is reduced, and the fear of wheel locking is avoided. after that,
The duty ratio of the pulse signal is gradually reduced, the flow rate of the pressurized liquid passing through the decay valve 9a and escaping to the reservoir 7 is gradually reduced, and the liquid pressure of the foil cylinder (W/C) is increased in inverse proportion to this. and the brakes are applied again. The above operations are then repeated as necessary. Note that during the above period, the cut valve 4a remains open.

Further, the above operation is the same when there is a possibility that the rear wheels may become locked.

Next, traction control will be explained.

If slip occurs on the drive shaft when the vehicle starts or accelerates, a signal from the wheel speed sensor (S) is sent to the control device (
ECU) or detect this.

Then, the main gate valve 2a and cut valve 4a are closed by a command from the control device (ECU), and the pump 10a is started.

First, the duty ratio of the pulse signal is set small, and the hydraulic pressure of the wheel cylinder (W/C) of the drive shaft (front wheel) is increased in the same manner as described above, thereby avoiding wheel slip. Thereafter, the duty ratio of the pulse signal is gradually increased, the hydraulic pressure in the wheel cylinder (W/C) of the drive shaft is reduced, and the brake is released. Then, the above operations are repeated as necessary.

As described above, the pressure liquid from the pump 10a is directly transferred to the foil cylinder (
An example in which the present invention is used to control the brake fluid pressure when applied to the mask cylinder (M/C) has been described, but as an anti-lock control device or traction control device, the brake fluid pressure from the mask cylinder (M/C) There is also a type of device that is controlled by a hydraulic pressure control device, and it is also possible to apply the present invention to a device of the type described above.

In other words, this type of device includes, although not shown, a pressurization chamber whose volume changes with the movement of the piston, and a hydraulic fluid chamber provided on the opposite side of the pressurization and depressurization chamber across the piston to move the piston. An example of such a structure is that a hydraulic pressure control device is equipped with a pressure control chamber, a pressurization chamber is connected to one wheel brake wheel cylinder, and a working fluid chamber is connected to a pump, an accumulator, or a reservoir via a solenoid valve. When the pressure fluid in the hydraulic fluid chamber is released to the reservoir, the volume of the pressure reduction chamber increases due to the movement of the piston, and the pressure fluid in the foil cylinder is absorbed into the pressure reduction chamber, reducing the brake fluid pressure. When the pressure fluid from the accumulator flows into the hydraulic fluid chamber and the piston moves, the volume of the pressure adjustment chamber becomes smaller, and the fluid pressure generated there is applied to the foil cylinder to increase brake fluid pressure.

Now, the hydraulic fluid chamber is regarded as the pressurized fluid supplied part of the present invention, the pump and the accumulator are regarded as the hydraulic pressure source of the present invention, and the solenoid valve is a pulse generator with a variable duty ratio as described above. When the operation is controlled, the hydraulic pressure in the hydraulic fluid chamber can be increased or decreased in the same manner as in the previous embodiment, and thereby the brake fluid pressure can be increased or decreased.

〔Effect of the invention〕

The present invention is economical because the hydraulic pressure can be controlled with one solenoid valve. In addition, there is only one valve part to open and close, which reduces the failure rate and ensures reliability compared to the conventional case where two valve parts are required.

Further, by continuously varying the duty ratio of the pulse signal, the hydraulic pressure can be increased and decreased continuously, and delicate adjustments can also be made.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an example of a device for realizing the method of the present invention, FIG. 2 is a hydraulic circuit diagram showing an example of an anti-lock and traction control device using the present invention, and FIG.
The figure is a block diagram of a control circuit centered around a microcomputer-based control device. 1...Pressure liquid supplied part, (IJ/C)...Foil cylinder as pressure liquid supplied part, 3 (3a, 3b, 3
at+ 3bT) -- Main liquid path, 8 (8a, 8b)
...Pressure reduction path, 9.. Solenoid valve, 9a, 9b.. Decay valve as a solenoid valve, 10.. Liquid pressure source, 10a, 10b.
...Pump as a source of hydraulic pressure.

Claims (1)

[Claims] (1) Connect a pressure reduction path that releases the pressure liquid in the pressure liquid supply part to the main liquid path that connects the hydraulic pressure source and the pressure liquid supply part that receives pressure liquid from this pressure source, and connect this pressure reduction path and A solenoid valve that is turned on and off by applying a pulse signal is inserted at an arbitrary position from the intersection of the main liquid path to the downstream side of the pressure reduction path, and the duty ratio of the pulse signal applied to this solenoid valve is changed. A method of controlling hydraulic pressure using a solenoid valve, characterized in that the hydraulic pressure of a part to which pressure liquid is supplied is controlled.