JPH0542589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a pressure control valve, and particularly to a pressure control valve such as a relief valve that controls flow in response to pressure on the inlet side.

(Prior art) As a specific example of a pressure control valve, for example,
There is a proportional electromagnetic relief valve described in Publication No. -90229. The configuration is schematically shown in FIG. 2, and as shown in the figure, an electromagnetic solenoid 52 is attached to one end surface (the left end surface in the figure) of the valve body 51.
In addition, a central through hole 5 is provided in the valve body 51 coaxially with a push rod 53 extending from the solenoid 52.
4 is drilled. A seat member 55 is disposed on the right end side of the center through hole 54 and is in contact with the inner peripheral surface of the center through hole 54. A valve body 55 is disposed between the seat member 55 and the push rod 53 of the solenoid 52.
6 is arranged so as to be freely slidable in the axial direction. A valve seat 57 is formed at the axial position of the end surface of the seat member 55 on the side of the valve body 56, and an oil passage 58 opening from the valve seat 57 to the outer peripheral wall surface of the seat member 55 is formed inside the seat member 55. It is set in. The inlet port 59 is connected to the oil passage 5 by the inflow passage 60.
8, and the outlet port 61 communicates with the outflow path 6.
2 communicates with the center through hole 54 on the side of the valve body 56 rather than the valve seat 57. Therefore, when the tapered valve portion 63 at the right end of the valve body 56 comes into contact with and separates from the valve seat 57, the inflow passage 60 and the outflow passage 62 are communicated through the valve seat 57. controlled. The electromagnetic force when energizing the solenoid 52 causes the valve body 56 to move to the right in the axial direction in the figure via the push rod 53, thus moving the valve body 56 in the valve closing direction where the valve portion 63 comes into contact with the valve seat 57. Acts as a pressing force. That is, by controlling the current supplied to the solenoid 52, the pressing force that urges the valve body 56 in the valve closing direction, that is, the relief pressure, is varied. When the pressure of the pressure oil introduced from the inlet port 59 into the oil passage 58 of the seat member 55 through the inflow passage 60 exceeds a pressure equivalent to the pressing force by the solenoid 52, the valve body 56 resists the pressing force. The inlet port 59 communicates with the outlet port 61 and a part of the pressure oil flows into the valve body 51.
by-passing through the inlet port 5
The pressure of the pressure oil supplied to the 9 side is controlled to be substantially constant.

(Problems to be Solved by the Invention) However, the conventional proportional electromagnetic relief valve described above has a problem in that it cannot be configured as a high-pressure, large-capacity relief valve. In other words, a force equal to the pressure of the pressure oil introduced into the oil passage 58 multiplied by the aperture area of the valve seat 57 acts on the valve body 56 in the closed state in the valve opening direction. The electromagnetic solenoid 52 needs to provide a force exceeding that amount. However, there is a limit to the pushing force that can be obtained with the electromagnetic solenoid 52, and in order to control with the pushing force that can be obtained with the electromagnetic solenoid 52, it is necessary to
It becomes necessary to make the opening area of 7 small. If the opening area of the valve seat 57 is configured to be small in this way, the flow path area will be small even when the pressure of the supply pressure oil exceeds the set value and the valve opens. The necessary bypass flow rate cannot be obtained, and as a result, the pressure of the supplied pressure oil exceeds the set pressure, making it impossible to perform the relief function.

The present invention has been made in view of the above, and an object thereof is to provide a pressure control valve capable of controlling high pressure and large flow rate.

(Means for Solving the Problems) Therefore, in the pressure control valve of the present invention, a spool sliding chamber 2 is provided in the valve body 1, and an inflow passage 14 and an outflow passage 15 are provided in the spool sliding chamber 2, respectively. The inflow passage 14 and the outflow passage 15 are opened, and the annular sliding surface 8 provided in the spool sliding chamber 2
A land portion 4 is provided on the spool 6 arranged in the spool sliding chamber 2 so that the land portion 4 can be slid on the sliding surface 8. By moving the spool 6 in the axial direction, the land portion 4 is moved into and out of the sliding surface 8, whereby the inflow path 14 and the outflow path 15 communicate with each other through the flow path, and are in a blocked state. The spool 6 is provided with a biasing means 20 for pressing the spool 6 in the valve closing direction, and the spool 6 is provided with a fluid introduction passage 25 opening at its end surface. and communicate this fluid introduction path 25 with the inflow path 14 through a flow path bored inside the spool 6,
A pressure receiving member 28 is slidably disposed within the fluid introduction passage 25, and the outward movement of the pressure receiving member 28 in the axial direction is restricted by the inner wall surface of the valve body 1. The spool 6 is configured to be able to be pushed in the valve opening direction by fluid pressure introduced into the valve.

(Function) In the above pressure control valve, the fluid introduced into the inflow path 14 side is further introduced into the fluid introduction path 25 provided in the spool 6, and the pressure receiving member inserted into this fluid introduction path 25. The pressure of the fluid acting on the end face of 28 generates a pressing force against the spool 6 in the valve opening direction. In other words, this pressing force is equal to the pressure of the fluid multiplied by the area of the end surface of the pressure receiving member 28. Therefore, even when the fluid pressure is large, by configuring the end face shape of the pressure receiving member 28 inserted into the spool 6 to be small, it is possible to reduce the pressing force. urging means 20 for pressing the spool 6 in the valve closing direction by
In this case, the axial movement of the spool 6 can be controlled by such a biasing means 20. When the pressing force due to the fluid pressure exceeds the pressing force of the urging means 20 and the spool 6 moves in the valve opening direction, the fluid flowing from the inflow path 14 to the outflow path 15 is changed by the spool 6. The flow will depend on the area of the channel.

Apart from the flow path controlled by the movement of the spool 6, a fluid introduction path 25 for controlling the movement of the spool 6 is formed in the spool 6, and this fluid introduction path 25 is connected to the flow path. Since the pressure control valve can be configured independently and small, it is possible to configure the pressure control valve as a high-pressure, large-capacity pressure control valve even when the pressing force in the valve-closing direction is small, such as in the case of an electromagnetic solenoid.

(Embodiments) Next, specific embodiments of the pressure control valve of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a pressure control valve according to an embodiment of the present invention configured as a proportional electromagnetic relief valve. In the figure, 1 is the valve body,
A spool sliding chamber 2 is provided inside the valve body 1 and extends through the valve body 1 in the left-right direction in the drawing. Part 4, right land part 5
A spool 6 having a spool 6 is arranged so as to be slidable in the axial direction. On the inner wall surface of the spool sliding chamber 2, first, second, and third sliding surfaces 7, 8, and 9, which are in contact with the respective lands 3, 4, and 5, are formed spaced apart from each other in the axial direction. At the same time, the large diameter region between the first and second sliding surfaces 7 and 8 in the spool sliding chamber 2 is connected to the inflow port chamber 10.
Also, the large diameter region between the second and third sliding surfaces 8 and 9 is formed as an outflow port chamber 11, respectively. On the other hand, an inlet port 12 and an outlet port 13 are provided on the outer peripheral wall surface of the valve body 1, and an inflow passage 14 that opens into the inflow port chamber 10 is provided.
is bored from the inlet port 12, and an outflow passage 15 that opens into the outflow port chamber 11 is bored from the outlet port 13.

The central land portion 4 of the spool 6 is provided with a plurality of passage holes 16 on its circumferential surface, which are directed toward the axis and communicate with the outflow port chamber 11 inwardly. Therefore, when the spool 6 is positioned as shown in FIG. Room 1
When located on the 0 side, the inflow port chamber 10 and the outflow port chamber 1 have a flow path area corresponding to the sum of the opening areas of the flow path holes 16 to the inflow port chamber 10.
1 will be in communication. By moving the spool 6 to the right side from the position shown in FIG.
0 becomes smaller, the communication flow area between the inflow port chamber 10 and the outflow port chamber 11 decreases, and furthermore, all of the flow path holes 16 are connected to the second sliding surface 8. When covered, communication between the inflow port chamber 10 and the outflow port chamber 11 is cut off, resulting in a closed valve state.

On the other hand, a blind plug 1 is located at the right end of the spool sliding chamber 2.
7 are screwed together to form an oil-tight state, and a valve spring 18 is disposed between this blind plug 17 and the right land portion 5 of the spool 6.
As a result, the spool 6 is pushed to the left in the axial direction. Further, an electromagnetic solenoid 20 serving as a biasing means is attached to the left end surface of the valve body 1, and the tip of a push rod 21 extending from inside the solenoid 20 into the spool sliding chamber 2 is connected to the spool 6.
is connected to the left end side. Above solenoid 20
By energizing the push rod 21,
An electromagnetic force is generated that tries to move the
This applies a force that presses the spool 6 in the valve closing direction.

Furthermore, the spool 6 has a small-diameter fluid introduction path 25 extending from the right end surface to the left about the axis position.
is drilled. The tip of this fluid introduction passage 25 extends to a small diameter shaft part 26 between the left land part 3 and the center land part 4 of the spool 6, and is bored radially in the radial direction at the position of this small diameter shaft part 26. It communicates with the inflow port chamber 10 via the communication hole 27 . On the other hand, on the right end side of the fluid introduction path 25, a piston 28 serving as a pressure receiving member is provided.
The left end side of is inserted and is in contact with the inner circumferential surface of the fluid introduction path 25 . The piston 28 and the spool 6 are movable relative to each other in the axial direction, and the enlarged diameter portion 29 formed on the right end side of the piston 28 is connected to the blind plug 17 that covers the right end side of the spool sliding chamber 2. The piston 28 is fitted into a recess formed at the axial center position of the end face of the piston 28, and the piston 28 is fitted into the bottom of the recess.
This piston 2
8 is restricted from moving to the right.

Next, the operating state of the proportional electromagnetic relief valve configured as described above will be explained.

First, when the electromagnetic solenoid 20 is de-energized, the spool 6 is pushed to the left by the spring force of the valve spring 18, so that the valve is in the open state shown in FIG. Hole 1
6 is located closer to the inflow port chamber 10 than the left end surface of the second sliding surface 8, so that the inflow path 14 and the outflow path 15 are in communication via the flow path hole 16. . And the above electromagnetic solenoid 2
By applying a predetermined current value to 0, the spool 6 moves from the valve opening position to the valve closing direction (first
(rightward in the figure) against the spring force of the valve spring 18, and the right end surface of the spool 6 is pushed against the blind stopper 1.
The valve is held in the closed position where it is in contact with the end face of the valve. At this time, the flow passage hole 16 in the central land portion 4 is covered with the second sliding surface 8, so that the communication state between the inflow passage 14 and the outflow passage 15 is cut off. In addition, in this valve closing position, the valve spring 1 is
A force obtained by subtracting the spring force of 8 is acting in the right direction.
As mentioned above, the valve spring 18 is provided to make this proportional electromagnetic relief valve a normally open type relief valve, that is, to provide an open state when the electromagnetic solenoid 20 is de-energized. , its spring force is relatively weak. Therefore, the pressing force in the valve closing direction when energized is equivalent to the electromagnetic force generated by the electromagnetic solenoid 20, and the following description will be made using this as the relief setting pressure.

When pressure fluid is introduced into the inflow port chamber 10 from the inlet port 12 through the inflow path 14 in the above-mentioned closed state, the fluid pressure generates a force that presses the spool 6 in the valve opening direction. That is, the fluid is further transferred from the inlet port chamber 10 to the spool 6.
The fluid is introduced into the fluid introduction path 25 through the communication hole 27 in the small diameter shaft portion 26, and a pressing force is generated on the end surface of the piston 28 that closes the right end side of the fluid introduction path 25. Since the piston 28 is restricted from moving in the right direction with respect to the valve body 1 via the blind plug 17, it is pushed in the left direction, that is, in the valve opening direction, with respect to the spool 6, which is movable in the axial direction within the spool sliding chamber 2. The pressure applied to the piston 28 acts as power. Therefore, when the pressure of the fluid flowing in from the inlet port 12 increases and the pressing force in the valve opening direction as described above also increases and exceeds the relief setting pressure by the electromagnetic solenoid 20,
The spool 6 is pushed to the left, that is, in the valve opening direction, and the left end side of the flow passage hole 16 in the central land portion 4 of the spool 6 is positioned within the inflow port chamber 10 beyond the left end surface of the second sliding surface 8. As a result, the inflow port chamber 10 flows through the flow path hole 16.
A bypass flow is generated from the outlet port chamber 11 to the outflow port chamber 11. The outlet port 13 leading to the outflow port chamber 11 is connected to a low-pressure pipe, so that the pressure increase in the inflow port chamber 10 is suppressed depending on the flow rate of the bypass flow, and the inflow fluid pressure at that time is suppressed. The spool 6 stops at a position where the pressure in the valve opening direction of the spool 6 and the relief set pressure by the electromagnetic solenoid 20 are balanced, and the spool 6 is held at that position.
The fluid pressure introduced into 2 is controlled to a predetermined pressure.

In the proportional electromagnetic relief valve described above, the force of the inflowing fluid that presses the spool 6 in the valve opening direction is given by multiplying that pressure by the area of the end surface of the piston 28 described above. Therefore, even when the inflow fluid has a high pressure exceeding, for example, 200 kg/cm ² , by configuring the diameter of the piston 28 to be small, the normal electromagnetic solenoid 2 can be used.
It is possible to control the movement of the spool 6 by balancing it with the electromagnetic force at
Regardless of the shape of the central land portion 4 of the spool 6
It is therefore possible to control the large flow rates obtained with conventional spool valves.

As described above, in the above embodiment, the movement of the spool 6 for controlling the flow path from the inflow path 14 to the outflow path 15 is performed in the fluid introduction path 25 provided in the spool 6 separately from the flow path. Since it is configured to respond to the pressing force generated by the action of fluid, even in a configuration in which the biasing force in the valve closing direction of the spool 6 is applied, for example, by the electromagnetic solenoid 20, the configuration as a high-pressure, large-capacity pressure control valve can be achieved. is possible. Further, as in the above embodiment, by providing the fluid introduction path 25 in the spool 6 to generate a pressing force in the valve opening direction of the spool 6, only the piston 28 as a pressure receiving member is added. It is possible to configure the above-mentioned relief valve with a simple structure, and therefore, no additional space is required other than the main body of the spool valve structure, such as a pilot valve body, so it can be configured compactly. In addition, since the structure is simple, manufacturing costs can be reduced. Furthermore, in the embodiment described above, the fluid pressure introduced into the fluid introduction path 25 from the inflow port chamber 10 is configured to generate a force that directly presses the spool 6 in the valve opening direction. Therefore, it is also possible to configure it as a relief valve that is less likely to cause chattering or the like. For example, from the fluid introduction path 25 to the outflow path 1
Since the configuration is such that no fluid flows out to the valve 5, and the necessary bypass flow is generated only on the spool valve side, fluid loss can also be suppressed to the necessary minimum.

Note that the above embodiments do not limit the present invention, and various modifications can be made within the scope of the present invention. For example, in the above embodiment, an electromagnetic solenoid 20 is provided as a biasing means, and a proportional electromagnetic relief valve is configured. Although an example has been described, the present invention can be applied to other relief valves or other pressure control valves in which a spring is provided as a biasing means in the valve closing direction, for example. Moreover, although the pressure receiving member 28 is constructed as a separate member in the above, it is also possible to construct it integrally with the inner wall surface of the valve body 1.

(Effects of the Invention) As described above, in the pressure control valve of the present invention, the movement of the spool for controlling the flow path from the inflow path to the outflow path is achieved by the fluid introduction provided in the spool separately from the flow path. Since the pressure is controlled according to the pressing force generated by the action of the fluid in the passage, even when the inflowing fluid has a high pressure, the pressing force generated in the fluid introduction passage can be configured to be small. Even when an electromagnetic solenoid is used as a biasing means to apply a pressing force in the valve closing direction against pressure, it is possible to configure the valve as a high-pressure, large-capacity pressure control valve. Suitable as a back pressure control valve, etc.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a pressure control valve configured as a proportional electromagnetic relief valve to which the present invention is applied, and FIG. 2 is a sectional view of a conventional proportional electromagnetic relief valve. 1...Valve body, 2...Spool sliding chamber, 4...
Land part, 6... Spool, 8... Slip surface, 2
0... Electromagnetic solenoid (biasing means), 25... Fluid introduction path, 28... Piston (pressure receiving member).

Claims (1)

[Claims] 1. A spool sliding chamber 2 is provided in the valve body 1, and an inflow path 14 and an outflow path 15 are respectively opened to the spool sliding chamber 2, and the inflow path 14 and the outflow path 15 are connected to the spool sliding chamber 2. The spool 6 is arranged so as to be able to communicate with each other through a flow path defined and formed by an annular sliding surface 8 provided in the chamber 2, and a land portion 4 is provided on the spool 6 arranged in the spool sliding chamber 2. The land portion 4 is brought into sliding contact with the sliding surface 8, and the land portion 4 is moved into and out of the sliding surface 8 by axial movement of the spool 6,
This is a pressure control valve configured to control the communication and cutoff state between the inflow path 14 and the outflow path 15 via the flow path, and a biasing means 20 that presses the spool 6 in the valve closing direction. While providing
The spool 6 is provided with a fluid introduction path 25 that opens at its end face, and the fluid introduction path 25 is a flow path that is formed inside the spool 6.
4, a pressure receiving member 28 is slidably disposed within the fluid introduction path 25, and the outward movement of the pressure receiving member 28 in the axial direction is restricted by the inner wall surface of the valve body 1; A pressure control valve characterized in that the spool 6 can be pushed in the valve opening direction by the fluid pressure introduced into the fluid introduction path 25.