JPH10169832A - Pilot valve - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the size of a device by enabling a plunger to have a small diameter. A plurality of plungers 30 are provided in a casing c.
Is slidably provided, an elastic means is interposed between the plunger and a push rod 22 provided coaxially, and by operating an operation lever 28 provided rotatably with respect to the casing, the push rod is pushed in. The plunger is moved against the elastic force of the elastic means while controlling the opening of the pump port according to the amount of movement of the plunger while balancing the pressure and elastic force of the output port acting on the pressure receiving surface of the plunger. And an annular groove formed on the outer periphery of the plunger by sequentially forming the tank port 10, the output port 2, and the pump port 7 toward the tip of the plunger.
While the output port communicates with the tank port or the pump port via 31, the tip of the plunger faces the pressure chamber 32 formed in the casing, and the pressure chamber communicates with the output port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot valve used in various industrial machines, and more particularly to a pilot valve whose output can be controlled in accordance with an operation amount of an operation lever.

[0002]

2. Description of the Related Art In the conventional example shown in FIG. 3, four valve mechanisms are incorporated in a casing C.
Only one valve mechanism appears. However, since the configurations of these valve mechanisms are the same, a description will be given below of the two valve mechanisms shown in FIG. The casing C is composed of the body 1 and four cylindrical members 20. Body 1
An output port 2 is formed at the bottom of the plunger, and a plunger insertion hole 3 and an assembly chamber 4 are formed in series with the output port 2. Note that a tank port 10 is formed in the body 1, and the assembly chamber 4 is always in communication with the tank port 10.

A plunger 5 is slidably inserted into the plunger insertion hole 3. In this plunger 5,
An opening 5 a is formed on the side surface, and a passage 5 b is formed along the axis of the plunger 5. The opening 5a is always in communication with the output port 2 via the passage 5b. In the middle of the plunger insertion hole 3,
An annular pump flow path 6 is formed, and this pump flow path 6 communicates with a pump port 7 formed in the body 1. The upper end of the plunger 5 is made to protrude into the assembling chamber 4 formed above the plunger insertion hole 3, and the cylindrical member 12 is fixed to the protruding portion. This cylindrical member 12
A collar is formed at the upper end of the first member, and a first spring 13 is interposed between the collar and the bottom of the assembly chamber 4.

On the other hand, a guide member 9 having a lower cylindrical portion is attached to the upper end of the assembly chamber 4, and a shaft member 11 is slidably inserted into the guide member 9. The shaft member 11 has a large-diameter portion on the upper side and a small-diameter portion on the lower side, and has a step at the boundary between the large-diameter portion and the small-diameter portion. In the small-diameter portion, a disk-shaped receiving member 17 having a cylindrical portion and a cylindrical member 1 having a brim are formed.
8 are slidably provided, and these two members 17,
18 are opposed vertically. The cylindrical member 18
Is prevented from coming off the shaft member 11 by a ring fixed to the lower end of the shaft member 11.

[0005] A second spring 14 holding an extension force is interposed between the two members 17 and 18 as described above. Therefore, by the action of the spring force of the second spring, the receiving member 17 normally comes into pressure contact with the step portion, and the cylindrical member 18 comes into pressure contact with the ring. The cylindrical member 1 thus constructed
8 is in contact with the upper end surface of the cylindrical member 12 pushed up by the first spring 13. Therefore, the plunger 5 and the shaft member 11 maintain the illustrated normal position by the action of the first spring 13 and the second spring 14. The plunger 5 at the normal position positions the opening 5a at an intermediate position between the pump flow path 6 and the assembly chamber 4, and maintains the opening 5a in a closed state. On the other hand, the shaft member 11 at the normal position is regulated by the receiving member 17 and keeps the step at the same level as the bottom of the guide member 9.

A third spring 1 separate from the second spring 14 is provided between the receiving member 17 and the cylindrical member 18.
5 is interposed. However, this third spring 15
Is shorter than the length between the members 17 and 18 maintaining the maximum distance. Therefore, when the shaft member 11 is pushed down, the second spring 14 bends first, and after a short time, the third spring 15 bends.

A cylindrical member 19 having an annular projection is incorporated in the lower inner periphery of the guide member 9. Although the upward movement of the cylindrical member 19 is restricted from the position shown in the figure, the cylindrical member 19 is slidable downward. A fourth spring 16 is interposed between the annular projection of the cylindrical member 19 and the middle part of the assembly chamber 4. When the shaft member 11 is at the normal position, a constant interval is maintained between the upper end of the cylindrical member 19 and the disk portion of the receiving member 17. When the receiving member 17 descends together with the shaft member 11, the disk portion of the receiving member 17 and the cylindrical member 19 collide,
Thereafter, the fourth spring 16 is bent.

A pedestal 24 is fixed to the upper opening of the assembly chamber 4 formed in the body 1, and the pedestal 24 is attached to the cylindrical member 2.
0 is fixed. An electromagnetic detent 21 is fixed to the upper end of the tubular member 20. A push rod 22 is slidably inserted into the electromagnetic detent 21,
At the lower end of the push rod 22, an adsorption member 23 made of a magnetic material is fixed. And the pedestal 24
And a suction member 23, a fifth spring 25 is interposed. Therefore, the push rod 22 maintains the illustrated normal position in which the tip protrudes from the electromagnetic detent 21.

A fixing member 26 having a function of bundling the plurality of electromagnetic detents 21 is fixed to the electromagnetic detent 21. Moreover, an operation lever 28 is rotatably attached to the center of the fixing member 26,
A flange 27 is fixed to the operation lever 28.
The push rod 2 pushed upward by the action of the plurality of springs is attached to the flange 27.
2 is configured to be in constant contact. Therefore, by making the push-up forces on all the push rods 22 equal, the operating lever 28 is kept vertical during normal operation.

If the operating lever 28 is tilted in the direction of the arrow in the drawing, the flange 27 tilts rightward in the drawing, and pushes the push rod 22 on the right side in the drawing. At this time, the left push rod 22 and the suction member 23 are pushed upward. When the suction member 23 hits the electromagnetic detent 21, the operation angle of the operation lever 28 is maximized.
Adsorb 3. Therefore, the operation lever 28 is maintained in the state where the maximum angle is maintained.

Next, the operation of the valve will be described. When the plunger 5 is in the illustrated normal position, the opening 5
a conflicts with the pump flow path 6 formed in the body 1 and the communication between the pump port 7 and the output port 2 is cut off. On the other hand, a communication hole 5c formed in the upper part of the passage 5b is open to the assembly chamber 4 side. Therefore, in this normal position, the output port 2 communicates with the tank port 10 via the passage 5b → the communication hole 5c → the assembly chamber 4.

When the operating lever 28 is operated in the direction of the arrow to push the push rod 22, the shaft member 11 is also pushed. When the shaft member 11 is pushed in this way, first, the first spring 13
While bending, according to the operation amount of the operation lever 28,
Other springs also bend sequentially. When the shaft member 11 is pushed in as described above, the plunger 5 is also lowered. When the plunger 5 moves downward in the figure, the communication hole 5c separates from the assembly chamber 4 and cuts off the communication between the passage 5b and the tank port 10. When the opening 5a overlaps the pump flow path 6, the pressure oil from the pump port 7 is supplied to the output port 2 via the passage 5b. The supply pressure to the output port 2 at this time is determined by the amount of wrap between the opening 5a and the pump port 7, that is, the opening degree of the pump port 7 and the flow rate flowing therethrough.

The pressure on the output port 2 side acts on the pressure receiving surface 8 which is the bottom surface of the plunger 5. At the same time, the elastic force of a plurality of springs provided in the assembly chamber 4 acts on the plunger 5 downward. Therefore, the plunger 5 has a pressure acting on the pressure receiving surface 8,
The position where the elastic force of the spring is balanced is maintained.
The opening of the pump port 7 is controlled according to the position of the plunger 5. If the pressure on the pressure receiving surface 8 of the plunger 5 is larger than the above-mentioned elastic force, the plunger 5 is pushed up to reduce the opening degree of the opening 5a with respect to the pump port 7. Conversely, if the pressure on the pressure receiving surface 8 is smaller than the elastic force, the plunger 5 is pushed down by the elastic force, and the opening 5a
To increase the opening. Thus, the pressure corresponding to the operation amount of the operation lever 8 is kept constant.

[0014]

In the above-mentioned conventional pilot valve, the passage 5b for communicating the output port 2 with the pump port 7 or the tank port 10 is formed in the plunger 5, so that the passage is formed. The diameter of the plunger 5 must be increased by 5b. In particular, the diameter of the passage 5 must be increased to some extent so that a sufficient amount of oil can be supplied to the output port 2.
The plunger diameter must be increased. As described above, when the diameter of the plunger is large, the pressure receiving area 8 becomes large, and accordingly, the elastic force of the spring to be balanced with the pressure must be increased. Therefore, there is a problem that the operation becomes heavy. In addition, when the plunger diameter is large, the sliding area between the side surface of the plunger 5 and the plunger insertion hole 2 becomes large, so that the frictional force becomes large and the operation becomes heavy.

If the size of the spring is increased in order to increase the elastic force of the spring, other parts such as the spring receiver are also increased in size, and the cost of the parts is increased. In addition, the plunger diameter and other parts are increased in size, the overall weight is increased, and the suction force of the electromagnetic detent 21 for maintaining the operation state must be increased. Therefore, the coil must be large, and the cost of parts increases. An object of the present invention is to provide a valve which can reduce the diameter of the plunger, reduce the size of the device, and solve the above-mentioned conventional problems.

[0016]

According to the present invention, a tank port, a pump port, and an output port are formed in a casing, a plurality of plungers are slidably provided, and the casing is provided coaxially with the plungers. By interposing elastic means between the push rod and the operating lever provided rotatably with respect to the casing, the plunger is moved against the elastic force of the elastic means while pushing the push rod, It is assumed that the pilot valve is configured to control the opening degree of the pump port according to the amount of movement of the plunger while balancing the pressure on the output port side acting on the pressure receiving surface of the plunger and the elastic force. While presuming the above-mentioned valve, the present invention provides each port with a tank port, an output port,
The pump port is formed in this order, and an annular groove is formed on the outer periphery of the plunger. Through this annular groove, the output port communicates with the tank port or the pump port. And the pressure chamber is connected to the output port.

As described above, the annular groove is formed on the outer periphery of the plunger, and the output port communicates with the tank port or the pump port through the annular groove. Therefore, the passage for communicating the output port with the tank port is provided. Need not be formed inside the plunger. Since no passage is formed inside the plunger, the diameter of the plunger can be reduced.
Further, since the annular groove is formed on the outer periphery of the plunger, the area of the sliding portion between the plunger and the body is reduced. The second invention is based on the pilot valve of the first invention, and is characterized in that a pressure introduction passage for introducing pressure on the output port side is formed in the plunger between the pressure receiving surface and the output port. Unlike the flow path for supplying the flow rate to the output port, the pressure introduction path does not need to be so thick, so that even if it is formed in the plunger, the diameter of the plunger does not increase. The pilot valve according to a third aspect of the present invention provides a pressure introduction path,
It is characterized in that it is formed on the body. Since the pressure introduction passage is formed not in the plunger but in the body, the diameter of the plunger can be further reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment shown in FIG. 1, the output port 2 is located between the tank port 10 and the pump port 7. Further, the plunger 30 is slidably inserted into the plunger insertion hole 3, but the tip of the insertion hole 3 is closed with a plug, and a pressure chamber 32 is formed between the plug and the plunger 30. I have. An annular groove 31 is formed on the outer periphery of the plunger 30. The annular groove 31 is always in communication with the output port 2 regardless of the movement position of the plunger 30. However, the annular groove 31 wraps around the assembly chamber 4 when the plunger 30 is at the normal position. However, when the plunger 30 is lowered, the annular groove 31 and the
The communication between them is cut off.

A pressure introducing passage 30b is formed in the plunger 30 in the axial direction.
b communicates with the annular groove 31 through an opening 30 a formed in the plunger 30. The plunger 30 protrudes from below into the assembly chamber 4, and the lower end of the shaft member 37 protrudes from above. The first to fourth springs 33 to 36 are provided outside the shaft member 37 and the plunger 30, and their positions are as follows.

An annular projection 37a is formed on the shaft member 37 projecting into the assembly chamber 4. And this annular projection 37
A receiving member 39 is provided so as to surround a, but the receiving member 39 is brought into direct contact with the guide member 9 similar to the conventional one. Further, a fourth spring 36 is interposed between the receiving member 39 and a step formed in the middle part of the assembly chamber 4. Therefore, receiving member 39
Keeps a state of direct contact with the guide member 9 in the normal position. At the lower end of the shaft member 37, a hollow portion 38 is formed. A flange formed at the upper end of the plunger 30 is slidably inserted into the hollow portion 38, and a stopper 40 is fixed below the hollow portion 38. The stopper 40 allows the plunger 30
Are prevented from falling out of the hollow portion 38. Then, a receiving member 41 is provided so as to cover the lower end of the shaft member 37.

The receiving member 41 as described above forms a first receiving portion 41a, a second receiving portion 41b, and a third receiving portion 41c from the inside thereof. And the third receiving portion 4
1c and the bottom of the assembly chamber 4 between the third spring 35
Is interposed. The receiving member 42 is slidably fitted to the plunger 30, and a step is formed in the middle of the plunger 30 to stop the receiving member 42.
The receiving member 42 includes first and second receiving portions 42a and 42b.
The first and second receiving portions 42a and 42
b is opposed to the first and second receiving portions 41a and 41b of the receiving member 41. A first spring 33 and a second spring 34 are interposed between the opposed receiving portions from the inside. In the normal state shown in the figure,
The first spring 33 is shorter than the facing distance between the upper and lower receiving portions, and the upper end is not in contact with the receiving member 41.

Next, the operation of the valve will be described. When the plunger 30 is at the normal position shown in the drawing, the annular groove 31 and the pump flow path 6 are not aligned, so that the pump port 7 and the output port 2 are shut off. On the other hand, since the annular groove 31 communicates with the assembly chamber 4, the output port 2 communicates with the tank port 10 via the annular groove 31. Also, the opening 30a opened in the annular groove 31 communicates with the tank port 10 as a matter of course.
2 is also maintained at tank pressure.

When the operating lever 28 is operated from the above state and the push rod 22 is pushed in, the plunger 30 moves accordingly. When the plunger 30 moves downward in the drawing, the annular groove 31 separates from the assembly chamber 4 and cuts off communication with the pump port 7. At the same time, the annular groove 31 wraps around both the pump flow path 6 and the output port 2, and the pressure oil from the pump port 7 is supplied to the output port 2 via the annular groove 31. The supply pressure to the output port 2 at this time is determined by the amount of wrap between the annular groove 31 and the pump flow path 6, that is, the opening degree of the pump port 7 and the flow rate flowing therethrough.

The supply pressure is introduced into the pressure chamber 32 through an opening 30a and a pressure introduction passage 30b. Therefore, the supply pressure on the output port 2 side acts on the pressure receiving surface 29 of the plunger 30. At the same time, the plunger 30
, The elastic force of the first to fourth springs 33, 34, 35, 36 installed in the assembly chamber 4 acts downward. Therefore, the plunger 30 is
And the elastic force of the spring are kept in a balanced position. The opening of the pump port 7 is controlled according to this position. This principle is the same as the conventional one.

The assembly chamber 4 and the cylindrical member 20 are
The five installed springs work stepwise as in the conventional example. First, when the push rod 22 is pushed in,
The shaft member 37 and the suction member 23 move, and the fifth spring 2
5 is compressed. As described above, the shaft member 37 moves integrally with the push rod 22, and accordingly, the receiving member 41 is pushed down, and the second spring 34 and the third spring
Press both springs 35. At this time, since the second spring 34 presses the receiving member 42, the plunger 30 also moves. When the receiving member 41 moves further downward together with the shaft member 37 and comes into contact with the upper end of the first spring 33, the pressing force of the first spring 33 acts. At the same time, the annular protruding portion 37a of the shaft member 37 abuts on a pressing portion 39a formed at the lower end of the receiving member 39, and presses the pressing portion 39a from above. When the pressing portion 39a is pressed down, the elastic force of the fourth spring 36 is also applied.

As described above, on the outer periphery of the plunger 30,
An annular groove 31 is formed, and the output port 2 communicates with the tank port 10 or the pump port 7 via the annular groove 31.
There is no need for a passage communicating the output port 2 and the tank port 10 inside 0. Therefore, the plunger diameter can be reduced. As the diameter of the plunger is reduced, the pressure receiving surface 29 of the plunger is also reduced, and the operating force can be reduced.

If the sliding area between the side surface of the plunger 30 and the plunger insertion hole 3 is large, the frictional force increases. In this embodiment, however, the frictional force decreases as the plunger diameter decreases. In addition, the sliding area between the plunger insertion hole 3 and the plunger 30 is further reduced by the formation of the annular groove 31 on the outer periphery of the plunger 30. In addition, unlike the flow path for supplying pressure oil to the output port 2, the pressure introduction path 30b does not need a flow rate,
There is no need to make it so thick. Therefore, plunger 3
Even if the pressure introduction passage 30b is formed in the cylinder 0, the diameter of the plunger does not need to be increased unlike the related art.

In the second embodiment shown in FIG. 2, the output port 2 and the pressure chamber 32 are directly connected to each other via a pressure introduction passage 43 formed in the body 1. This is the first embodiment. Is different from Other configurations and operations are the same as those of the first embodiment, and thus detailed description thereof will be omitted. In the second embodiment as described above, since the pressure introducing passage 43 is formed directly in the body 1, the plunger 44 does not need to have the pressure introducing passage as in the first embodiment. As a result, the diameter of the plunger can be further reduced as compared with the first embodiment. Therefore, the operation force for moving the plunger 44 can be reduced. Accordingly, the coil of the electromagnetic detent 21 can be made compact and cost can be reduced.

[0029]

According to the first to third aspects of the present invention, the output port communicates with the tank port or the pump port via the annular groove formed on the outer periphery of the plunger. Therefore, the output port communicates with the tank port. It is no longer necessary to form a passage inside the plunger. Therefore, the diameter of the plunger can be reduced. In particular, in the third aspect, since the pressure introduction passage is formed in the body, the diameter of the plunger can be further reduced. As a result, the pressure receiving area of the plunger is reduced, so that the pressure acting on the pressure receiving surface is reduced, and the elastic force for balancing the pressure can be reduced. Since the elastic force can be reduced, the size of the spring can be reduced, the structure of the spring receiving member can be simplified, and the cost of parts can be reduced. Further, when the diameter of the plunger is reduced, the area of the sliding portion between the plunger and the body is reduced, and the frictional force can be reduced. In addition, since the annular groove is formed on the outer periphery of the plunger, the area of the sliding portion between the plunger and the body is reduced, and the frictional force is further reduced. As a result, the operating resistance of the plunger was reduced, and the operating force could be reduced. Further, since the plunger and other components can be reduced in size, the size of the coil of the electromagnetic detent can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 C Casing 2 Output port 7 Pump port 10 Tank port 22 Push rod 25 Fifth spring 28 Operating lever 29 Pressure receiving surface 30, 44 Plunger 33-36 First to fourth spring 30b Pressure introducing path 31 Annular groove 43 Pressure introducing path

Claims (3)

[Claims] 1. A casing having a tank port, a pump port, and an output port, a plurality of plungers slidably provided, and elastic means provided between the plunger and a push rod provided coaxially. By operating an operating lever provided rotatably with respect to the casing, the plunger is moved against the elastic force of the elastic means while pushing the push rod, and an output acting on the pressure receiving surface of the plunger is provided. In a pilot valve configured to control the opening of the pump port according to the amount of movement of the plunger while balancing the pressure and the elastic force on the port side, in the pilot valve, each port is directed toward the tip of the plunger, a tank port, An output port and a pump port are formed in this order, and an annular groove is formed on the outer periphery of the plunger. A pilot valve, wherein the output port communicates with the tank port or the pump port, while the plunger tip faces a pressure chamber formed in the casing, and the pressure chamber communicates with the output port. . 2. The pilot valve according to claim 1, wherein a pressure introduction passage is formed in the plunger, and the output port and the pressure chamber are communicated via the pressure introduction passage. 3. The pilot valve according to claim 1, wherein a pressure introduction passage is formed in the casing, and the output port and the pressure chamber are communicated via the pressure introduction passage.