JPH0321557A - Valve control method for air over hydraulic brake - Google Patents

Abstract

PURPOSE:To reduce the air consumption by turning on an electromagnetic hold valve immediately when a brake switch is put off, thereby encapsulating the air in an air pressure chamber, turning off the valve, and holding the valve closed condition with the pressure in the air pressure chamber. CONSTITUTION:A control valve according to the present invention includes an electromagnetic hold valve 4, which is interposed between an air pressure chamber 2 of a modulator 1 for air-over hydraulic brake and brake valve 3 and which is energized in the direction of opening by a valve spring 5. When brakes are disengaged and a brake switch is put OFF, this electromagnetic hold valve 4 is turned ON for a certain period of time. Thereby the valve 4 is once closed against the action of the valve spring 5 to boost the internal pressure of the air pressure chamber 2, and then the valve 4 is turned off. Thereafter the valve 4 is kept in closed condition by the pressure fed from the air pressure chamber 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a valve for air-over-hydraulic brakes.

[Conventional technology]

As a structure of this type of conventional air-over-hydraulic brake modulator 1, one having a schematic mechanism shown in FIG. 2 is known.

In the figure, a pneumatic chamber 2 that also serves as a cylinder for a piston P is provided in this air over hydraulic brake modulator 1, and the rear end of this piston P constitutes another piston PC. , this piston PC
The pressure of the foil cylinder W/C can be increased or decreased through the . An electromagnetic hold valve 4 operated by a solenoid S is inserted between the pneumatic chamber 2 and the brake valve 3. This electromagnetic hold valve 4 is provided with a valve body 4a that is biased in the opening direction by a valve spring 5, and when the solenoid S is in the OFF state, the valve body 4a is
The pneumatic chamber 2 in the figure is moved by the biasing force of the valve spring 5.
At this time, with the electromagnetic hold valve 4 open, air can flow from the brake valve 3 through passage A and passage B in the electromagnetic hold valve 4 into the pneumatic chamber 2. It becomes.

By the way, in this type of mechanism, while the internal pressure of the pneumatic chamber 2 drops to the same level as atmospheric pressure when braking is not applied, it must be increased to a corresponding level when braking is applied. As a result, there was a fear that the brake response would decrease.

Therefore, in order to improve the brake response and brake braking efficiency, the air pressure chamber 2 of the modulator 1 is always filled with air above a certain level, and when braking, the air pressure chamber 2 is further filled with air from this constant pressure. The inside was pressurized.

That is, at the time when the brake valve 3 is opened, the air in the pneumatic chamber 2 is released from the brake valve 3 into the atmosphere through the passage B and the passage A in the electromagnetic hold valve 4. At this time, the valve body 4a is attracted to the valve 1iBa side (the right side in the figure) in the electromagnetic hold valve 4 due to the flow velocity of the air in the passage B, the electromagnetic hold valve 4 is closed, and air is released into the pneumatic chamber 2. I was starting to feel trapped.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, when the brake valve is slowly opened, for example, the predetermined flow velocity cannot be obtained in the passage B, so the valve body 4a cannot be attracted to the valve seat 6a side, and the pneumatic chamber There were cases where sufficient air could not be contained within the unit.

The present invention has been made in view of the above-mentioned problems, and is an air-over system that can always contain air above a certain pressure in the pneumatic chamber of the modulator and reduce air consumption by simply adding a simple control procedure. An object of the present invention is to provide a valve device for hydraulic brakes.

[Means to solve the problem]

The present invention has the following means to solve the above problems.

That is, the air over hydraulic brake has an electromagnetic hold valve 4 inserted between the pneumatic chamber 2 of the air over hydraulic brake modulator 1 and the brake valve 3 and biased in the opening direction by a valve spring 5.・In the brake control valve, when the brake is released and the brake switch is OFF, the electromagnetic hold valve 4 is kept ON for a predetermined period of time, and the electromagnetic hold valve 4 is once closed against the valve spring 5 and then emptied. After increasing the internal pressure of the pressure chamber 2, the electromagnetic hold valve 4 is turned off, and then the pneumatic chamber 2 is turned off.
The closed state of the electromagnetic hold valve 4 is maintained by the pressure from the valve.

[Effect]

According to the above-described means, the electromagnetic hold valve 4 is turned on immediately after the brake switch is turned off, and the air in the air pressure chamber 2 is forcibly held. In this way, once the electromagnetic hold valve 4 is turned on and the valve body 4a is attracted to the valve seat 6a side, the electromagnetic hold valve 4 is turned off. After this, the increased air pressure in the pneumatic chamber 2 maintains the adsorption state of the valve body 4a, so that the containment of the air in the pneumatic chamber 2 is maintained.

In this way, since the air is reliably contained,
It is possible to reduce air consumption and improve braking efficiency.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a control device III of an air over hydraulic brake valve device which is an embodiment of the present invention, and FIG. Over◆Hydraulic◆Shows the schematic structure of a brake valve device.

Air over of this embodiment ◆ A pneumatic chamber 2 that also serves as a cylinder is provided in the hydraulic brake modulator 1, and a piston P is accommodated in this pneumatic chamber 2 so as to be slidable in the axial direction. ing.

The rear end of this piston P (on the right side in the figure) constitutes a piston PC of another hydraulic system, and the pressure of the foil cylinder W/C can be increased or decreased via this piston PC.

Between the pneumatic chamber 2 and the brake valve 3, there is a return valve R for preventing an overpressure condition in the pneumatic chamber 2, an electromagnetic hold valve 4 for controlling the pressure condition in the pneumatic chamber 2, and a A decay valve 7 for forcibly exhausting the inside of the pressure chamber 2 is inserted.

A valve body 4 a is slidably accommodated inside the electromagnetic hold valve 4 , and this valve body 4 a is biased toward the pneumatic chamber 2 by a valve spring 5 . That is, when the solenoid S is not energized, the electromagnetic hold valve 4 is biased in the opening direction. The biasing force of the valve spring 5 is such that when there is no pressure in the pneumatic passage 12 connecting the electromagnetic hold valve 4 and the brake valve 3, the pressure maintained at a certain level in the pneumatic chamber 2 causes the valve body 4a to move toward the valve body. Compress the spring 5 to compress the valve seat 6
The strength is set to allow pressure contact with a.

A valve seat 6a that can come into contact with the valve body 4a is provided on the brake valve 3 side of the electromagnetic hold valve 4, and when the valve body 4a comes into contact with the valve 1i6a, the electromagnetic hold valve 4 is closed. The structure is such that the flow of air to the passage A is suppressed.

Next, the control method in the above structure will be explained using FIG.

First, when the brake is depressed, air from the brake valve 3 is sent into the pneumatic chamber 2 via the passage A and the passage B in the electromagnetic hold valve 4, and at this time, the inside of the pneumatic chamber 2 is A predetermined high pressure state is maintained (step 101).

Next, with the brake valve 3 open (102)
A signal from the brake switch is detected and the solenoid S is turned on for a predetermined period of time (103). This solenoid S
The valve body 4a is instantaneously attracted to the valve iBa side by the electromagnetic force, the passage B, that is, the electromagnetic hold valve 4 is closed, and the air in the pneumatic chamber 2 is sealed. By energizing the solenoid S in this manner, the electromagnetic hold valve 4 is instantaneously closed. Regarding this point, in the prior art, the valve element 4a was attracted to the valve 11i6a only by the pressure of the air from the pneumatic chamber 2;
When the brake is released slowly, the flow rate of air from the pneumatic chamber 2 to the passage B is insufficient, so the closing of the electromagnetic hold valve 4 is delayed or insufficient, resulting in air leakage, and the air inside the pneumatic chamber 2 is This made it difficult to maintain a predetermined pressure.

In this embodiment, as described above, by energizing the solenoid S, the valve body 4a is forcibly and instantaneously attracted to the valve seat 6a side, so that air leakage in the pneumatic chamber 2 can be prevented. A predetermined pressure within the pneumatic chamber 2 can be reliably maintained.

Next, in a state where the valve body 4a is attracted to the valve seat 6a, the energization to the solenoid S is cut off (104).

However, at this time, the valve element 4a is maintained in a state of adsorption against the valve seat 6a within the electromagnetic hold valve 4 due to the inflow pressure of air from the pneumatic chamber 2 against the valve spring 5. .

It should be noted that the valve body 4 that has become adsorbed (occluded) in this way
When the brake is pressed again, the pressure in the passage A increases and the valve spring 5 moves to the right in the figure to open the electromagnetic hold valve 4.

〔Effect of the invention〕

According to the present invention, air can be reliably trapped in the pneumatic chamber 2, the amount of air consumed can be reduced, and the braking efficiency of the brake can be increased.

[Brief explanation of the drawing]

Fig. 1 shows a control procedure for an air-over-hydraulic brake valve device according to an embodiment of the present invention, and Fig. 2 shows an outline of the air-over-hydraulic brake valve device to be controlled. It shows the structure. 1 ◆ 2◆ 3◆ 4◆ 4a 5◆ Modulator, pneumatic chamber, brake valve, electromagnetic hold valve, ・Valve body, valve spring, 6a...valve seat, 7...decay valve, 12・◆・Air pressure path, A...Passage, B...Passage, P...Piston, PC...Piston, R◆...Return valve, S...Solenoid, W/C・◆・Wheel cylinder,

Claims (1)

[Claims] (1) It has an electromagnetic hold valve 4 inserted between the pneumatic chamber 2 of the air over hydraulic brake modulator 1 and the brake valve 3 and biased in the opening direction by a valve spring 5, With the brake released and the brake switch turned OFF, the electromagnetic hold valve 4 is kept ON for a predetermined period of time, and the electromagnetic hold valve 4 is temporarily closed against the valve spring 5 to increase the internal pressure of the pneumatic chamber 2. After that, turn the electromagnetic hold valve 4 to O.
A method for controlling a valve for an air-over hydraulic brake, characterized in that the valve is brought into an FF state, and thereafter a closed state of an electromagnetic hold valve 4 is maintained by pressure from a pneumatic chamber 2.