JPH0355079Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a differential pressure detection valve suitable for detecting a pressure difference between two types of high and low pressure fluids.

Generally, various devices are operated by the differential pressure between a high-voltage circuit and a low-voltage circuit. Since detection is performed by calculation, there is a drawback that the detection device is relatively complicated or expensive. Therefore, the applicant first proposed a high pressure inlet a and a low pressure inlet b as shown in the first diagram.
In the valve housing e in which a differential pressure port c and a drain port d are formed, a first sliding position connects the differential pressure port c to the high pressure inlet a, and connects the differential pressure port c to the drain port d. a second sliding position;
A slidable spool f is provided at an intermediate position between the second sliding position, and a first pressure receiving surface g on which the fluid pressure of the high pressure inlet a acts on one end side of the spool f, and a first pressure receiving surface g on which the fluid pressure of the high pressure inlet a acts on the other end side. Second and third pressure receiving surfaces h, i having the same area and facing the first pressure receiving surface g, on which the fluid pressure of the inlet b and the fluid pressure of the differential pressure port c act, respectively.
The above-mentioned drawbacks were solved by proposing a valve in which a pressure difference is required between the fluid pressures acting on the high-pressure inlet a and the low-pressure inlet b at the differential pressure port c of the valve.

However, in this device, there is a restriction that high pressure must act on high pressure inlet a and low pressure must act on low pressure inlet b. For example, high pressure and low pressure must be alternated, such as in a circuit where a hydraulic motor rotates in forward and backward directions. There is an inconvenience that it cannot be used in such cases.

The purpose of the present invention is to provide a differential pressure detection valve that does not have such inconveniences.
A first sliding position that connects the differential pressure port 3 to the high pressure inlet 1 and a second sliding position that connects the differential pressure port 3 to the drain port 4 in the valve housing 5 formed with the
A slidable spool 6 is provided between the first and second sliding positions, and one end of the spool 6 has a first pressure receiving surface 7 on which the fluid pressure of the high pressure inlet 1 acts, and the other end The fluid pressure of the low pressure inlet 2 and the fluid pressure of the differential pressure port 3 act on the side, and second and third surfaces having the same area and facing the first pressure receiving surface 7 are provided.
The pressure receiving surfaces 8 and 9 are provided, and the valve housing 5
A circuit 19, 2 is formed between the two pressure measurement ports 10, 11 in the valve housing 5 and the high pressure inlet 1 and the low pressure inlet 2.
A high/low pressure selection spool 14 is provided which moves with the pressure of each pressure measurement port 10, 11 acting on both ends 12, 13, respectively, through 0;
At the intermediate position of the movement, the high pressure introduction port 1 and the low pressure introduction port 2 are closed, and at the movement position to one side, one pressure measurement port 10 is connected to the high pressure introduction port 1, and the other pressure measurement port 11 is connected to the low pressure introduction port. 2, and in the other moving position, the other pressure measurement port 11 is connected to the high pressure inlet 1, and one pressure measurement port 10 is connected to the selection spool 1.
The two land portions 14a, 14 are connected to the low pressure inlet 2 via the cross passage 21 formed in the 4.
b.

The embodiment of the present invention is as shown in the second figure, in which a flow path 15 is formed at one end of the spool 6, and the high pressure of the high pressure inlet 1 is passed through the flow path 15 to the first
A land portion 16 is formed which acts on the pressure receiving surface 7 and is large enough to close the differential pressure port 3. Furthermore, a step portion 17 is formed on the other end side of the spool 6, and each surface of the land portion 16 acts on the pressure receiving surface 7 and closes the differential pressure port 3. The fluid pressure between the second pressure receiving surface 8 and the differential pressure port 3, on which the fluid pressure of
The third pressure-receiving surface 9 acts through the third pressure-receiving surface 9. Since each pressure receiving surface 7, 8, and 9 has the same area, the first sliding position, that is, the high pressure inlet 1 is connected to the differential pressure port 3 only when the pressure at the high pressure inlet 1 is lower than the pressure at the high pressure inlet 1. When the pressure of the low pressure inlet 2 is higher than the pressure of the high pressure inlet 1, the second sliding position, that is, the differential pressure port 3 is moved to the drain port 4. to prevent pressure from being led out from the high pressure inlet 1 to the differential pressure port 3, and to discharge the pressure in the differential pressure port 3. Furthermore, when both inlets 1 and 2 are at the same pressure, The spool 6 is located at an intermediate position between the first and second sliding positions, and no pressure is led out to the differential pressure port 3. In the illustrated example, the spool 6 is composed of two separate left and right members 6a and 6b, but it may be an integral member.

The above configuration is not particularly different from the one proposed earlier, but in the present invention, two pressure measurement ports 10, 11 and a high/low pressure selection spool 14 are further provided in the valve housing 5, and each port 10, 11 is actuation of said selection spool 14 allows both ports 10,
11, the high pressure side of one is connected to the high pressure inlet 1, and the other low pressure side is connected to the low pressure inlet 2.
so that it is connected to. The selection spool 14 has a respective pressure measuring port 10,
The spool 14 is actuated by the pressure introduced from the spool 11 through the circuits 19 and 20, and has lands 14a and 14b in the middle of the spool 14 that close the high pressure inlet 1 and the low pressure inlet 2 when the spool 14 is in the middle position. At the same time, on the outside of each land portion 14a, 14b, an end portion of a cross passage 21 connecting one port to one inlet when the spool 14 slides in one direction is opened. According to this configuration, for example, when the pressure of the pressure measurement port 10 is higher than the other port 11, the spool 14 is in the position shown in the figure, and the port 10 is connected to the high pressure inlet 1, and at the same time, the port 11 is connected to the low pressure inlet 2. However, if the pressure in port 10 is lower than the other port 11, spool 1
4 slides to the left in the drawing, port 10 crosses passage 2
1 to the low pressure inlet 2, and at the same time, the port 11 is connected to the high pressure inlet 1 via the land 14a.

In this way, according to the present invention, the differential pressure between the fluid pressures of the high pressure inlet 1 and the low pressure inlet 2 is obtained at the differential pressure port 3 by the operation of the spool 6, and the pressure measuring ports 10 and 11 are obtained by the high/low pressure selection spool 14. When high and low pressure is selected, the high pressure side port is connected to high pressure inlet 1 and the low pressure side port is connected to low pressure inlet 2, so when the pressure level of the two circuits whose differential pressure is to be measured is not constant. It is possible to detect differential pressure even if there is a problem, and its structure is simple and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of a conventional example, and FIG. 2 is a cutaway side view of an embodiment of the present invention. 1...High pressure inlet, 2...Low pressure inlet, 3...
Differential pressure port, 4...Drain port, 5...Valve housing,
6... Spool, 7... First pressure receiving surface, 8... Second
Pressure receiving surface, 9... Third pressure receiving surface, 10, 11... Pressure measurement port, 12, 13... Both ends, 14... High/low pressure selection spool.

Claims (1)

[Scope of utility model registration request] A first sliding position connecting the differential pressure port 3 to the high pressure inlet 1 is provided in the valve housing 5 in which the high pressure inlet 1, the low pressure inlet 2, the differential pressure port 3, and the drain port 4 are formed, and the differential pressure A slidable spool 6 is provided at a second sliding position connecting the port 3 to the drain port 4 and at an intermediate position between the first and second sliding positions, and the high pressure inlet is provided at one end of the spool 6. A first pressure receiving surface 7 on which the fluid pressure of No. 1 acts, and the low pressure inlet 2 on the other end side.
and a fluid pressure of the differential pressure port 3, respectively, and are provided with second and third pressure receiving surfaces 8 and 9 having the same area as the first pressure receiving surface 7 and facing the first pressure receiving surface 7. 5 to 2 pressure measurement ports 1
0, 11, and both ends 12, 13 are connected via circuits 19, 20 between both pressure measurement ports 10, 11 in the valve housing 5 and the high pressure inlet 1 and the low pressure inlet 2.
A high/low pressure selection spool 14 is provided which moves with the pressure of each pressure measurement port 10, 11 acting on the pressure measurement port 10, 11, respectively. In the movement position, one pressure measurement port 10 is connected to the high pressure inlet 1 and the other pressure measurement port 11 is connected to the low pressure inlet 2, and in the movement position to the other side, the other pressure measurement port 11 is connected to the high pressure inlet 1. Connected to high pressure inlet 1 and one pressure measurement port 1
0 formed in the selection spool 14
A differential pressure detection valve is provided with two land portions 14a and 14b so as to be connected to a low pressure inlet 2 via a pressure inlet 2.