JP2000264193A - Four-way protection valve for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain generation of abnormal sound caused by supply of air to a secondary chamber by differing the valve opening pressure between a first check valve and a second check valve constituting two supply passages extending from a primary chamber to the secondary chamber. SOLUTION: Taking the valve opening pressure of a first check valve D1 connected to a primary chamber A1 through an orifice E1 as a reference, the valve opening pressure of a secondary check valve D2 connected to the primary chamber A1 through a second orifice E2 is set about 150% to 500%. Thus, the supply of air from the primary chamber A1 to the secondary chamber A2 is concentrated on the first check valve D1. Accordingly, the supply of air to the secondary chamber A2 is mainly performed through the passage with the first check valve D1. When the supply flow rate of the first check valve D1 is short, the second check valve D2 is opened to secure the supply of air. Therefore, two check valves are alternately opened to restrain generation of abnormal sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-way protection valve for a vehicle, and more particularly to a four-way protection valve capable of avoiding generation of abnormal noise when air is supplied to a secondary side.

[0002]

2. Description of the Related Art In a vehicle in which a service brake, a parking brake, a clutch, a suspension, or other accessories are operated by air pressure, it is necessary to use a 4-way protection valve to increase the reliability of an air system. is there.

Such a four-way protection valve for a vehicle is configured as shown in FIGS. 1 and 2, for example, and a first piston valve B1 and a first piston valve B1 are supplied to a primary chamber A1 to which air is supplied from an air tank (not shown). The first output port C1 and the second output port C2 are connected via a two-piston valve B2.

The secondary side (output port C1) of the first piston valve B1 and the secondary side (second output port C2) of the second piston valve B2 are connected by a first check valve D1 and a second check valve D2, respectively. It is connected to the secondary chamber A2 via two supply paths, and a third check valve D3 and a fourth check valve D4 and a third piston valve B3 and a fourth check valve D4 are connected to the secondary chamber A2.
The third output port C3 and the fourth output port C4 are connected via a piston valve B4.

Therefore, the air supplied to the primary chamber A1 is:
First piston valve B1 and second piston valve B2
Through the first output port C1 and the second output port C2. At the same time, a part of the air sent from the first piston valve B1 and the second piston valve B2 is sent to the secondary chamber A2 through a supply path by the first check valve D1 and the second check valve D2.

Further, the fuel is sent from the secondary chamber A2 to the third output port C3 through the third check valve D3 and the third piston valve B3, and is also sent through the fourth check valve D4 and the fourth piston valve B4 to the fourth output port C4. Will be sent to E1, E2 and F1, F2 are a first piston valve B1 and a second piston valve B2.
And an orifice and a check valve connecting the primary side and the secondary side.

In the four-way protection valve having such a configuration, the first or second valve provided in the primary chamber A1 is provided.
If the air circuit connected to the output port fails, the piston valve of the failed circuit automatically closes to protect the air of other circuits, and at the same time, the first and second check valves D1, D2 are opened. The pressure in the secondary chamber E is maintained. When the air circuit connected to the third or fourth output port provided in the secondary chamber A2 fails, the check valve provided on the piston valve closes and fails in the same manner as when the primary side fails. Keep the air pressure in the circuit that is not being used.

Then, by refilling the primary chamber A1 with air, the air pressure in the primary chamber A1 and the secondary chamber A2 is increased until the opening pressure of the piston valve of the failed circuit is reached, and the primary chamber A1 is lost. In the event of a failure, other circuits can be refilled with air to a certain pressure, such as by supplying air to a circuit that does not have an output port.

By the way, the first and second check valves D1, D constituting the supply path to the secondary chamber A2 as described above.
The valve opening pressure of No. 2 cannot be made completely the same due to variations in machining or assembly even if the design is completely the same, and the orifice E
1, the pressure downstream of E2 is maintained the same when the check valves D1 and D2 are closed, but decreases as the check valves are opened.

For this reason, when air is supplied to the secondary chamber A2, the two check valves D1 and D2 do not open at the same time, but the valve opening pressure is slightly lower, for example, the first check valve D2.
1 opens first. Further, since the pressure downstream of the first orifice E1 becomes lower than the pressure downstream of the second orifice E2 with the opening of the check valve D1, the first check valve D1 which has been open up to that time is closed. The second check valve D2 opens.

Then, the pressure downstream of the second orifice E2 is reduced by opening the second check valve D2, and the first pressure is reduced by the supply of air from the primary chamber A1.
In order to increase the pressure downstream of the orifice E1 until it becomes equal to that of the primary chamber A1, the two check valves D1 and D2 are closed, so that the second check valve D2 is closed and the first check valve D1 is opened. D2 opens the valve alternately to generate an operation sound, which is transmitted outside the machine as an abnormal sound.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to suppress generation of abnormal noise from a vehicle 4-way protection valve accompanying supply of air to a secondary chamber. Is an issue.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first check valve and a second check which constitute two supply paths from a primary chamber to a secondary chamber in a 4-way protection valve for a vehicle. It is characterized by different valve opening pressures.

[0014]

Embodiments of the present invention will be described below in detail. That is, in the present invention, the first check valve D1 connected to the primary chamber A1 via the orifice E1.
By setting the valve opening pressure of the second check valve D2 connected to the primary chamber A1 via the second orifice E2 to about 150% to 500% on the basis of the valve opening pressure of the secondary chamber from the primary chamber A1 to the secondary chamber. The supply of air to A2 is concentrated on the first check valve D1.

Accordingly, the supply of air to the secondary chamber A2 is performed mainly through the path of the first check valve D1. When the supply flow rate of the first check valve D1 is insufficient, the second check valve D2 opens to secure the supply flow rate of air. For this reason, unlike the conventional case, the two check valves do not open alternately to generate abnormal noise. Further, since the two supply paths are provided to secure the supply flow rate as a whole, the air pressure in the secondary chamber A2 does not abnormally decrease even when a large amount of air is consumed. There is no loss of reliability.

In order to make the valve opening pressures of the first check valve D1 and the second check valve D2 different, it is general to make the spring characteristics of the set springs used for both valves different, but the same. In a case where the intended purpose is achieved by making the mounting dimensions of both springs different by using a set spring having specifications, there is an advantage that an increase in the number of parts can be suppressed.

[0017]

As is apparent from the above description, according to the present invention, an air supply path to the secondary chamber is formed through two supply paths each having a check valve. Because the valve opening pressure is different,
Normally, air supply to the secondary chamber is performed using only one supply path, and air is also supplied from the other supply path only when the flow rate of air supply from this supply path is insufficient. Because of this, the frequency of opening and closing of the check valve due to air supply is reduced, and the operating noise of the check valve transmitted as abnormal noise to the outside of the machine is reduced.

[Brief description of the drawings]

FIG. 1 is an air circuit diagram of a 4-way protection valve for a vehicle to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a specific example of a 4-way protection valve for a vehicle to which the present invention is applied.

[Explanation of symbols]

 A1 Primary chamber A2 Secondary chamber B1 First piston valve B2 Second piston valve B3 Third piston valve B4 Fourth piston valve C1 First output port C2 Second output port C3 Third output port C4 Fourth output port D1 First Check valve D2 Second check valve D3, D4 Check valve E1, E2 Orifice F1, F2 Check valve

Claims (1)

[Claims] A first chamber provided with a first and a second output port; and a secondary chamber provided with a third and a third output port. In a four-way protection valve for a vehicle connected via two supply paths including a first check valve and a second check valve, the opening pressures of the first check valve and the second check valve are different from each other. Way protection valve.