JPS6318061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a double check valve connected to a pressure fluid piping line.

<Prior art> Due to the pressure difference between the pressure fluid flowing into the pressure fluid reception port from two directions, one reception port is closed with a valve body, and the pressure fluid flowing in from the other reception port is fed into one A double check valve that discharges from the outlet is known, for example, from Japanese Utility Model Application No. 52-14731.

This known double check valve is provided with a pressure fluid reception port at both ends of the valve casing in the axial direction, and a delivery port in a direction perpendicular to the axis at approximately the center between the two reception ports. communicates with the delivery port through a flow path within the valve casing,
This structure includes a valve body that opens and closes each of the receiving ports from inside, and a spring that biases each valve in a normally closed direction between the valve bodies.

<Problems to be Solved by the Invention> In the double check valve of the conventional structure described above, when the pressure fluid at both reception ports is equal pressure, both valve bodies open equally to send the pressure fluid flowing from both reception ports. The two flow paths in front of the outlet merge and flow out from the delivery port, but the pressure of the pressure fluid at one intake port drops, the valve body closes this one intake port, and the valve body of the other intake port closes. When the pressure fluid that flows in from the other intake port is opened and flows out from the delivery port, the two channels in front of the delivery port communicate with each other and into the casing in which the spring is installed, so the other The pressure fluid flowing in from the receiving port flows into the open back surface of the valve body via the flow path. By this,
In addition to the force acting in the closing direction from the spring, back pressure from the pressure fluid acts on the open valve body, pushing the valve body in the closing direction.As a result, pressure fluid is applied to the inlet and outlet sides. There are also problems such as a pressure difference between the two sides of the valve body, and the valve body opening and closing due to the pressure difference on both sides of the valve body, causing the flow of the pressure fluid to pulsate.

<Means for Solving the Problems> The present invention provides a double check valve that solves the above-mentioned conventional problems, and its characteristic structure is that pressure is applied to the valve casing at both ends in the axial direction. A fluid reception port and a fluid delivery port are provided in a direction perpendicular to the axis at an approximately intermediate position between the two reception ports, and a sleeve communicating with the two reception ports is fitted in the valve casing in the axial direction, A concave groove passage communicating with the outlet is provided in the axial direction on the outer circumferential surface of the sleeve facing the outlet, and a through hole is provided through which both ends of the groove passage communicate with the inside of the sleeve,
A first valve element that opens and closes each intake port from inside is slidably fitted in the sleeve, and the first valve element allows the passage of the sleeve only when the intake ports are open. A passage communicating with the hole is provided, and a second valve body is provided in the first valve body so as to be freely openable and closable on this passage, and a second valve body is pressed between the back faces of both the first valve bodies in a direction to close them. A first spring with a large set load is interposed, and a second spring with a small set load is installed on the back surface of both second valve bodies to press the respective second valve bodies in the closing direction. A breathing hole is bored in the sleeve and valve casing to communicate the space inside the sleeve with outside air.

<Function> With the above-described configuration, the present invention has the same pressure as the pressure fluid in both receiving ports, and when the pressure is higher than the pressing force of the first spring with a large set load, the first valve body and the second valve body The valve body opens and the pressurized fluid flows out from both of the through holes through the concave groove and the outlet. In addition, when the pressure fluid on the one side of the intake port drops to a pressure lower than the pressure of the second spring with a small set load, the second valve body immediately closes the passage of the first valve body, and the fluid flows in from the other intake port. All of the pressurized fluid flowing through the other hole flows out from the outlet through the concave groove passage. Further, the inside of the sleeve between the first valve bodies through the opening/closing operation of the first valve element performs a breathing action through a vent hole communicating with the atmosphere, thereby facilitating the opening/closing operation of the first valve element.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, 1 is a valve casing, and pressure fluid intake ports 2 are provided at both ends in the axial direction of the valve casing.
3, and a delivery port 4 is provided in a direction perpendicular to the axis at an approximately intermediate location between the receiving ports 2 and 3.

Further, a sleeve 5 that communicates with both the receiving ports 2 and 3 is fitted in the valve casing 1 in the axial direction. This sleeve 5 is provided with a concave groove passage 7 in the axial direction on the outer peripheral surface facing the outlet port 4 and communicating with the outlet port 4, and a through hole 6 through which both ends of the concave groove passage 7 communicate with the inside of the sleeve 5 is provided. It is provided.

Further, inside the sleeve 5 are first valve bodies 8a and 8b for opening and closing the respective receiving ports 2 and 3 from the inside.
are fitted so as to be slidable in the axial direction, and communicate with the through hole 6 of the sleeve 5 only when the receiving ports 2, 3 are opened in the first valve bodies 8a, 8b.
9b is provided. Second valve bodies 10a, 10b are provided inside the passages 9a, 9b so as to be openable and closable.

Next, a first spring 11 with a large set load for pressing both first valve bodies 8a, 8b in the closing direction is interposed between the back surfaces of both first valve bodies 8a, 8b, and both second valve bodies 10a, Second springs 12a and 12b with a small set load press the respective second valve bodies 10a and 10b in the closing direction on the back surface of the second valve body 10b.
It is installed. Further, a ventilation hole 13 is provided in the sleeve 5 and the valve casing 1 to communicate the space inside the sleeve 5 between the first valve bodies 8a and 8b with the outside air.

Since the present invention has the structure as described above, the pressure fluid introduced into both the receiving ports 2 and 3 is supplied to the first spring 1.
When the pressure is greater than the set load of No. 1 and the pressure is equal, both first valve bodies 8a, 8b open, and passages 9a, 8b open.
9b, the second valve bodies 10a and 10b are opened, and the liquid is sent out from the outlet via the through hole 6 and groove passage 7.
Here, in the event that one of the pressure tanks or piping connected to the intake ports 2 and 3 is damaged and released to atmospheric pressure, the second valve body 10a or 10b on the damaged side In addition to the pressure from the undamaged side, the passage 9a or 9b is immediately closed, creating a double check valve action that prevents the normal side pressure from being released into the atmosphere. Note that when the pressure on the damaged side becomes less than the set load of the first spring 11, the first valve body 8a or 8b closes the receiving port 2 or 3 on the damaged side.
will be closed. Therefore, the pressure from the normal side continues to be sent to the outlet 4.

Additionally, if the system from the outlet 4 is damaged, the pressure will gradually drop at the same rate in the intake ports 2, 3 and the outlet 4, but when the pressure decreases to the protection pressure of the set load of the first spring 11, the pressure will drop. The first valve bodies 8a and 8b close immediately to cut off the discharge from the outlet 4, and the piping system before the intake ports 2 and 3 never falls below the protection pressure.

Furthermore, a first
The back space of the valve bodies 8a, 8b communicates with the atmosphere through the vent hole 13, and the back pressure of the first valve bodies 8a, 8b is always open to atmospheric pressure, and breathing is prevented by opening and closing the first valve bodies 8a, 8b. The first valve body 8a, 8b
The movement is smooth.

Conventionally, a trailer brake system has a front tank 2 of an air tank 20 as shown in FIG.
0a and the rear tank 20b are connected to the inlet of a normal double check valve 21, and the protection valve 22 is connected to the outlet thereof, and the protection valve 22 is connected to the trailer via the air cock 23 to the emergency cut-off spring 24. was connected. Reference numeral 25 denotes a brake valve, and its operation supplies air pressure from the front tank 20a or rear tank 20b to the brake system of the tractor, and also supplies air pressure to the trailer via the double check valve 26, relay valve 27, and service coupling 28. It also supplies braking equipment. Therefore, if the front or rear brake chamber system of the tractor is damaged, double check valve 21
If the emergency line system of the trailer is damaged, the pressure in the air tank 20 is maintained without being released to the atmosphere by closing the protection valve 22. However, for this purpose, the double check valve 21 and the protection valve 22 are required to be separate parts as described above, which increases the cost and the number of man-hours for assembling the piping.

However, as shown in FIG. 3, by assembling only the double check valve 29 of the present invention having the above structure in place of the conventional double check valve 21, the installation of the conventional protection valve 22 is unnecessary and the emergency braking performance is satisfied. The brake system can be simplified while reducing costs, and costs can also be reduced.

In addition, if the front tank 20a or rear tank 20b is damaged, the second valve body 10a or 10b on the damaged side is immediately moved to the receiving port 2 on the damaged side by the second spring 12a or 12b and the normal pressure. or 3 is closed, so there is no loss of pressure in the tank on the normal side and full pressure is maintained on both the emergency side and the tank.

<Effects of the Invention> As described above, according to the present invention, a sleeve that communicates with the receiving ports at both ends is fitted in the valve casing in the axial direction, and a sleeve that communicates with the receiving ports at both ends is fitted in the valve casing in the axial direction at a substantially intermediate portion between the receiving ports. A concave groove passage communicating with the outlet is provided in the axial direction on the outer circumferential surface of the sleeve on the side facing the outlet provided in a direction perpendicular to the outlet, and a through hole is provided through which both ends of the groove passage communicate with the inside of the sleeve. A first valve body for opening and closing the respective intake ports from the inside is fitted in the sleeve so as to be slidable in the axial direction. A passage communicating with the through hole is provided, and a second valve body is provided on the passage within the first valve body so as to be freely openable and closable, and a passageway is provided between the back surfaces of both the first valve bodies in the direction of closing both the first valve bodies. This is because a first spring with a large set load to press is interposed, and a second spring with a small set load to press each second valve body in the closing direction is installed on the back of both second valve bodies. , since the back surface between the first valve bodies is isolated from the pressure fluid flow path by the sleeve,
Pressure fluid does not go around to the back surface of the first valve body, and no back pressure due to the pressure fluid is applied to the opened first valve body. Therefore, the opened first valve body is urged in the closing direction by the back pressure of the pressure fluid to generate a pressure difference between the pressure fluid between the intake port and the delivery port, or the pressure fluid is generated by the opening and closing swing of the first valve body. This eliminates the inconvenience of flow pulsation.

Also, the second valve body always opens at the pressure at which the first valve body opens, but when the pressure at the inlet drops below the set load of the second spring, the second valve body opens even if the first valve body is open. Since the passage is immediately closed at the pressure drop, the response to the pressure drop can be quickly and reliably obtained.If the line to the intake port connecting the pressure tank is normal, the pressure tank on the side where the pressure has dropped will be at the normal pressure. This prevents pressure from accumulating in the system, and in the event of damage to the system, the pressure on the normal side is released from the damaged side to the atmosphere.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a double check valve according to the present invention, FIG. 2 is a piping diagram of a conventional trailer brake system, and FIG. 3 is a piping diagram of a trailer brake system equipped with the double check valve of the present invention. 1... Valve casing, 2, 3... Intake port,
4...Outlet port, 5...Sleeve, 6...Through hole, 7
...Concave groove passage, 8a, 8b...First valve body, 9a,
9b...Passage, 10a, 10b...Second valve body, 1
1...first spring, 12a, 12b...second
Spring, 13...Vent hole.

Claims (1)

[Claims] 1. The valve casing is provided with a pressure fluid reception port at both ends in the axial direction, and a delivery port in a direction perpendicular to the axis at an approximately intermediate position between the two reception ports, and the both reception ports are provided in the valve casing. A sleeve communicating with the outlet is fitted in the axial direction, and a concave groove passage communicating with the outlet is provided in the axial direction on the outer peripheral surface of the sleeve facing the outlet, and both ends of the concave groove passage communicate with the inside of the sleeve. A through hole is provided, and a first valve body for opening and closing the respective receiving ports from inside is fitted in the sleeve so as to be slidable in the axial direction.
The valve body is provided with a passage that communicates with the through hole of the sleeve only when the receiving port is open, and on this passage, a second valve body is provided in the first valve body so as to be freely openable and closable. A first spring with a large set load that presses both first valve bodies in the closing direction is interposed between the back surfaces of the valve bodies, and a first spring with a large set load that presses the respective second valve bodies in the closing direction is provided on the back surfaces of both the second valve bodies. A double check valve characterized in that a second spring with a small set load is installed, and a breathing hole is bored in the sleeve and the valve casing to communicate the space inside the sleeve between the first valve bodies and the outside air.