JP3138202B2 - Pressure reducing valve type pilot valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-reducing valve type pilot valve which is suitable for use in, for example, switching control of a directional control valve in a main circuit by reducing and outputting pressure oil from a pilot hydraulic pressure source. About the valve.

[0002]

2. Description of the Related Art An example in which a pressure reducing valve type pilot valve according to the prior art is used in a pilot hydraulic system of a hydraulic shovel will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a casing constituting a main body of a pressure reducing valve type pilot valve, and inside the casing 1, pressure reducing valve portions 2A and 2B having the same structure and other pressure reducing valve portions (not shown). ) Are realized. Hereinafter, constituent elements corresponding to the pressure reducing valve units 2A and 2B are indicated by subscripts A and B.

Here, the casing 1 is always in communication with a pump port 3 through which hydraulic oil flows from a hydraulic pump (not shown) as a pilot hydraulic pressure source, and a tank (not shown) in which the oil liquid is recirculated. Tank port 4, spring chambers 5 </ b> A, 5 </ b> B constantly communicating with the tank port 4,
A, 5B, guide tube mounting holes 6A, 6B, and guide tube 7A inserted into the guide tube mounting holes 6A, 6B.
7B, pusher insertion holes 8A, 8B formed in the guide cylinders 7A, 7B, into which pushers 13A, 13B described later are slidably inserted, and coaxial with the pusher insertion holes 8A, 8B. Output ports 9A and 9B provided on the lower end side of the casing 1 and connected to a direction switching valve (not shown) on the main circuit side, and the output ports 9A and 9B communicate with the pump port 3 and the tank port 4. And spring chamber 5
A, 5B and spool sliding holes 10A, 10B and the like formed between the output ports 9A, 9B.

On the other hand, the pressure reducing valve sections 2A and 2B are provided with spools 11A and 11B, pushers 13A and 13B, return springs 14A and 14B, and setting springs 16A and 16B.
It is roughly composed of The pressure reducing valve sections 2A, 2B
Have the same structure, only the configuration of the pressure reducing valve section 2A will be described below.

Reference numeral 11A denotes a spool slidably provided in a spool sliding hole 10A. In the spool 11A, an output port 9A is connected between the pump port 3 and the tank port 4 according to the position of the spool 11A. A flow path 12A communicating with one of them is formed in the radial direction and the axial direction.

13A has a guide cylinder 7A at one end (lower end).
A pusher slidably inserted into the pusher insertion hole 8A. The other end (upper end) of the pusher 13A is formed in a hemispherical shape and has a protruding end protruding outside the casing 1. . Further, a small gap (not shown) is formed between the pusher 13A and the guide cylinder 7A, and through this gap, the oil liquid in the casing 1 (spring chamber 5A) reaches a seal member 22A to be described later. It is being supplied.

Reference numeral 14A denotes a return spring disposed in the spring chamber 5A. The return spring 14A pivots the pusher 13A via a spring receiving member 15A to return the pusher 13A to the initial position shown in the figure. It is always urged upward.

16A is a pusher 13A and a spool 11A.
And a setting spring that sets the pressure of the spool 11A on the output port 9A side in accordance with the amount of pressing operation on the pusher 13A.
It is located inside the return spring 14A in the spring chamber 5A, and is disposed with a predetermined preset load between the spool 11A and the pusher 13A.

Reference numeral 17 denotes an operation lever which is tilted by a driver or the like in directions indicated by arrows A and B.
Is a rod-shaped lever body 18, a cam 19 integrally fixed to the lever body 18, and a connecting portion 20 composed of a cross joint or the like, which is disposed in a cab (not shown) of the excavator.
And a mounting member 21 and the like screwed to the casing 1 side. The base end side of the lever main body 18 is swingably connected to the mounting member 21 via a connecting portion 20.

The cam 19 projects radially outward from the base end of the lever main body 18, and the lower surface thereof is the pusher 1
It is in contact with the upper end (projecting end) side of 3A, 13B and the like. Then, the cam 19 tilts in response to a tilting operation performed by the driver or the like on the operation lever 17, whereby the pushers 13A,
13B is pressed.

Reference numeral 22A denotes an annular seal member. The seal member 22A is mounted in a circumferential groove formed in the inner peripheral surface (the pusher insertion hole 8A) of the guide cylinder 7A. This prevents foreign matter and the like from entering between the two from outside, and also prevents the oil liquid in the casing 1 from leaking to the outside.

An upper cover 23 covers the upper end side of the casing 1.
The guide cylinders 7A and 7B inserted into A and 6B are held in a retaining state.

The pressure-reducing valve type pilot valve according to the prior art has the above-described configuration, and its operation will be described below.

First, when the operating lever 17 is at the neutral position (initial position) as shown in the figure, the flow path 12A of the spool 11A shuts off the pump port 3 and the output port 9A, and connects the tank port 4 and the output port 9A. , The output port 9A is in a low pressure state. The same applies to the spool 11B, and the output port 9B is also in a low pressure state. As a result, the direction switching valve of the main circuit is held at the neutral position.

Next, when the driver or the like operates the operating lever 17 in one of the directions indicated by the arrows A and B, for example, the direction indicated by the arrow A, the cam 19 is tilted with the connecting portion 20 as a fulcrum, thereby pushing the pusher 13A. Is pressed downward in the axial direction, and the spool 11A is slid downward in the axial direction via the setting spring 16A according to the amount of pressing operation at this time. Thereby, the flow path 12A of the spool 11A makes the pump port 3 communicate with the output port 9A, and shuts off the tank port 4 and the output port 9A.

As a result, the pressure in the output port 9A is set to a high pressure state, and the pressure in the output port 9A acts on the spool 11A as feedback pressure.
1A slides upward in the axial direction against the spring load of the setting spring 16A, and at this time, the setting spring 16A is compressed from the preset state and bent.

The flow path 12A of the spool 11A is
When the pump port 3 and the output port 9A are shut off again and the tank port 4 and the output port 9A communicate with each other, the pressure in the output port 9A decreases, so that the setting spring 16A extends from the compressed state. The spool 11A is again slid downward in the axial direction by the spring load of the setting spring 16A. As a result, the flow path 12A of the spool 11A allows the pump port 3 and the output port 9A to communicate with each other and shuts off the tank port 4 and the output port 9A, so that the pressure in the output port 9A increases.

That is, a spring load corresponding to the amount of pressing operation on the pusher 13A is generated in the setting spring 16A, and the pressure in the output port 9A is controlled in accordance with the spring load. The switching valve is switched from the neutral position to the switching position with a stroke amount corresponding to the pressure (pilot pressure) in the output port 9A.

As described above, in the conventional pressure reducing valve type pilot valve, by controlling the switching of the direction switching valve by operating the pressure reducing valve section 2A, the flow rate of the pressure oil flowing into the main circuit via the direction switching valve is controlled. Can be gradually controlled from a small flow rate to a large flow rate. And the operation lever 17
Is tilted in the direction of arrow B, the arrow A
As in the case where the tilting operation is performed in the direction, the direction switching valve can be switched and controlled by the operation of the pressure reducing valve unit 2B, and the flow rate of the pressure oil in the main circuit can be controlled.

Accordingly, the driver tilts the operation lever 17 or the like to an appropriate position, and thereby operates the actuators such as the hydraulic cylinders and the turning motors connected to the main circuit in accordance with the operation speed corresponding to the tilting operation amount. The excavator can be operated by rotating the boom, the arm, the bucket, and the like of the excavator (up and down movement), and the upper revolving body can be swung.

[0022]

By the way, in the above-mentioned prior art, the driver tilts the operation lever 17 or the like to an appropriate position while sitting in the cab of the hydraulic excavator, so that the boom, arm, The bucket and the upper revolving superstructure are operated at an intended operation speed and operation amount, and excavation work of, for example, earth and sand is performed.

For this reason, in the prior art, the operation lever 17
The hydraulic pressure (pilot pressure) on the output port 9A side can be finely adjusted with high responsiveness by a slight tilting operation, so that the driver can finely operate the boom, arm, bucket, upper revolving superstructure, and the like. I can do it.

However, if the responsiveness of the pilot pressure to the tilting operation of the operation lever 17 is improved, vibrations during running, shocks when riding on unevenness of the road surface, centrifugal force due to the turning operation of the upper turning body, etc. In some cases, the driver's body shakes due to the action, and the operation lever 17 or the like grasped by the hand is erroneously tilted. If the pilot pressure of the pilot valve changes due to the tilting operation, the boom, arm, bucket And the upper revolving superstructure or the like is operated against the driver's will, and the maneuverability of the hydraulic shovel is deteriorated.

The present invention has been made in view of the above-described problems of the prior art, and can prevent a pusher from being erroneously pressed by an external vibration or the like, and can solve problems such as flapping and malfunction of an operation lever. It is another object of the present invention to provide a pressure reducing valve type pilot valve capable of improving the operability and stability of an operation lever.

[0026]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a casing having a pump port, a tank port, and an output port, and a slidably provided casing, wherein the output port is connected to a pump. A spool communicating with one of the port and the tank port, a pusher one end of which is slidably inserted into the casing for slidingly displacing the spool and the other end of which protrudes out of the casing; A setting spring, which is disposed between the spool and the pusher and sets the pressure of the output port side by the spool in accordance with the amount of pressing operation of the pusher; and for pressing the pusher against the setting spring. The present invention is applied to a pressure reducing valve type pilot valve comprising an operating lever having a cam abutting on a protruding end side of the pusher.

[0027] Then, in the invention according to claim 1, between the casing and the pusher gives a sliding resistance to the pusher with respect to the pressing operation of the pusher, and the Pusshi
A plurality of grooves or to allow the hydraulic fluid flows in the sliding direction of the turbocharger
A resistance ring having a through oil holes, as characterized in that the hydraulic fluid in than the resistance ring located in the projecting end toward the pusher the casing is provided with a sealing member for sealing the leakage to the outside I have.

With this configuration, the resistance phosphorus
When the pusher is pressed with a small pressing force than the sliding resistance due grayed (frictional force), the sliding resistance of the resistor ring
The pusher I can suppress e <br/> Rukoto from being slidably displaced in the housing. When the pusher is pressed with a pressing force larger than the sliding resistance, the pusher is slidably displaced within the casing, and a pressure corresponding to the pressing operation can be generated on the output port side. Also,
The resistance ring has a plurality of grooves or oil passages that allow the flow of oil liquid.
Since the oil passage having the hole is provided, the oil liquid in the casing can be supplied to the periphery of the pusher up to the position of the seal member disposed closer to the protruding end of the pusher than the resistance ring ,
The sliding surface between the pusher and the casing can be maintained in a lubricated state.

In the invention according to claim 2, the casing is provided with a guide tube which constitutes a part of the casing and guides the pusher slidably, and between the guide tube and the pusher. The resistance ring and the seal member are provided.

Thus, the resistance ring and the seal member can be disposed between the guide cylinder and the pusher with the guide cylinder removed from the casing, and thereafter, the resistance ring, the seal member and the pusher are disposed within the guide cylinder. In this state, by attaching this guide tube to the casing,
The work of assembling the resistance ring , the seal member, and the like can be easily performed.

[0031]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments, the same components as those in the related art are denoted by the same reference numerals, and description thereof will be omitted. Further, components corresponding to the pressure reducing valve sections 2A and 2B are indicated by subscripts A and B.

First, FIGS. 1 to 4 show a first embodiment of the present invention.

In the figure, reference numerals 31A and 31B denote guide cylinders according to the present embodiment. The guide cylinders 31A and 31B are formed in a substantially cylindrical shape, and the guide cylinder mounting holes 6A and 6B of the casing 1 are provided.
And is fixed to the casing 1 in a state where the casing 1 is inserted.
The guide cylinders 31A and 31B have resistance rings 40A and 40B, seal rings 44A and 44B and O
Rings 39A, 39B and the like are provided. Since the guide tube 31A and 31B have the same structure, only the configuration of the guide tube 31A will be described below.

Reference numeral 32A denotes a pusher insertion hole 32A into which the pusher 13A is slidably inserted. As shown in FIG. 2, the pusher insertion hole 32A is formed by the inner peripheral surface of the guide cylinder 31A. And the pusher insertion hole 32A
The opening end of one side (lower side) is enlarged stepwise to form a stepped portion 33.
A, the pusher 13A is inserted into the pusher insertion hole 32A, and the lower end of the flange shape is the stepped portion 33A.
Abuts on the outside of the casing 1.

A resistance ring groove 34A is formed as a concave circumferential groove at one end (lower end) of the pusher insertion hole 32A, and a seal ring groove 35A is substantially formed at the other end (upper end). A convex positioning portion 36A for positioning the seal ring 44A is formed so as to protrude from a bottom surface inside the seal ring groove 35A.

On the other hand, the outer peripheral side of the guide cylinder 31A is a large-diameter portion 37A whose lower end protrudes radially outward, and the large-diameter portion 37A is inserted into the guide cylinder mounting hole 6A of the casing 1. In this state, it is stopped by the upper lid 23. An annular O-ring groove 38A is formed in the large-diameter portion 37A, and an O-ring 39A made of an elastic material such as rubber or resin material is mounted in the O-ring groove 38A. Ring 39A is casing 1
By elastically contacting the guide cylinder mounting hole 6A and the guide cylinder 31A, the oil liquid in the casing 1 is prevented from leaking to the outside from between them.

40A is a resistance ring groove 3 of the guide cylinder 31A.
4A shows a resistance ring as a resistance member mounted in the resistance ring 40A. As shown in FIG. 3, the resistance ring 40A is made of an elastic resin material such as urethane rubber or the like. The pusher 13A has a through hole 41A at the center thereof. A plurality of recesses 42A, 42 having the same depth dimension are provided on the insertion hole 41A side.
Are formed at regular intervals, so that the convex portions 43A, 43A,... Are formed between the concave portions 42A.

The bottom side of each recess 42A is disposed on the same circumference having the recess hole diameter Do, and the tip side of each projection 43A is located on the circumference having the projection hole diameter Dt. Thus, the insertion hole 41A is formed as a gear-shaped hole having a concave hole diameter Do and a convex hole diameter Dt. Further, as shown in FIG. 4, each of the protrusions 43A is formed in a substantially triangular cross section with the tip end pointed toward the inner peripheral side, whereby the resistance ring 40A has a pentagonal cross section.

Here, the insertion hole 41A has a concave hole diameter D
o, the convex hole diameter Dt is the outer diameter Dp of the pusher 13A.
(See FIG. 2) so that Dt <Dp <Do.

As shown in FIG. 2, the resistance ring 40A is mounted in the resistance ring groove 34A of the guide cylinder 31A, and in this state, the pusher 13A is inserted into the pusher insertion hole 32A of the guide cylinder 31A. The outer peripheral side is disposed between the guide cylinder 31A on the casing 1 side and the pusher 13A with the inner peripheral side contacting the outer peripheral surface of the pusher 13A and the inner peripheral side contacting the resistance ring groove 34A side of the guide cylinder 31A. .

As a result, at the position of each convex portion 43A of the insertion hole 41A, the outer diameter Dp of the pusher 13A is changed to the insertion hole 41A.
Is larger than the convex hole diameter Dt of the convex portion 43A, each convex portion 43A is pressed by the pusher 13A so as to be pushed to the outer peripheral side, whereby the distal end side of each convex portion 43A has the outer diameter dimension Dp and the convex portion. In a state where the outer peripheral surface of the pusher 13A is elastically brought into contact with the outer peripheral surface of the pusher 13A with a pressing force corresponding to the deformed dimension in a state where the outer peripheral surface of the pusher 13A is deformed so as to be crushed to the outer peripheral side by a dimension difference from the hole diameter Dt. .

Since the diameter Do of the recessed hole of the insertion hole 41A is larger than the outer diameter Dp of the pusher 13A, the position of each recessed portion 42A of the insertion hole 41A in this state is in contact with the bottom of the recessed portion 42A. Gaps G, G,... (Only two are shown) communicating between the seal ring 44A side and the inner side of the casing 1 are formed between the outer circumference of the insertion hole 41A and the outer circumference of the insertion hole 41A. I have.

Reference numeral 44A denotes a seal ring as a seal member mounted in the seal ring groove 35A of the guide cylinder 31A. As shown in FIG. 2, the seal ring 44A is formed of an elastic resin material such as rubber, for example. The outer peripheral side is the mounting portion 45A, and the inner peripheral side is bifurcated upward and downward in FIG.
An oil seal lip 47A is provided. A metal core 4 made of a metal material and having an L-shaped cross section is provided inside the mounting portion 45A.
8A is embedded, and the core metal 48A extends to the inner peripheral side of the seal ring 44A, whereby the seal ring 44A maintains sufficient strength.

The seal ring 44A is attached to the mounting portion 45.
A is fixed in the seal ring groove 35A of the guide cylinder 31A via the positioning portion 36A, and the dust seal lip 46
A, the tip side of the oil seal lip 47A is the pusher 13
In a state of sliding contact with the outer peripheral surface of A, it is disposed between the guide cylinder 31A and the pusher 13A at a position closer to the protruding end (upper end) of the pusher 13A than the resistance ring 40A. Thereby, the seal ring 44A prevents foreign matter and the like from the outside from entering between the guide cylinder 31A and the pusher 13A by the dust seal lip 46A, and also prevents the foreign matter or the like from entering between the guide cylinder 31A and the pusher 13A by the oil seal lip 47A. The leakage of the oil liquid interposed in the outside is sealed.

The pressure reducing valve type pilot valve according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

In this embodiment, however, the resistance ring 40A is disposed between the guide cylinder 31A provided on the casing 1 side and the pusher 13A, and the pusher 13A sliding in the guide cylinder 31A is attached to the resistance ring 40A. Since the sliding contact is provided, when the pusher 13A slides in the guide cylinder 31A, a certain sliding resistance can be given to the pusher 13A by the resistance ring 40A.

That is, the resistance ring groove 34 of the guide cylinder 31A
A, a resistance ring 40A is mounted in the resistance ring 40A.
Is configured such that the front end side of each convex portion 43A is elastically brought into contact (sliding contact) with the outer peripheral surface of the pusher 13A.
A is slid in the guide cylinder 31A by pushing the pusher 1
3A must be slid and displaced against a sliding resistance (frictional force) generated between the tip of each convex portion 43A of the resistance ring 40A, and the pusher 13A is pressed with a pressing force smaller than the sliding resistance. In this case, the pusher 13A can be reliably held at rest.

The insertion hole 41A of the resistance ring 40A
The convex hole diameter Dt is smaller than the outer diameter Dp of the pusher 13A to provide sliding resistance to the pusher 13A. Therefore, by changing the convex hole diameter Dt of the insertion hole 41A, The resistance ring 40 can easily adjust the magnitude of the sliding resistance with respect to the pusher 13A, and presses the pusher 13A reliably only when a tilting force is intentionally applied to the operation lever 17.
The sliding resistance by A can be set to an appropriate value.

Therefore, when the driver or the like intentionally tilts the operation lever 17, the pusher 13A can be reliably pushed through the operation lever 17 or the like.
On the other hand, when a slight tilting force is applied to the operation lever 17 by mistake, the pusher 13A is caused by this tilting force.
Can be reliably prevented from sliding displacement by the sliding resistance of the resistance ring 40A. As a result, the pressure-reducing valve-type pilot valve malfunctions due to an unintended lever operation of the driver, and it is possible to reliably prevent an unexpected operation of the arm, the boom, etc., and to greatly improve the maneuverability of the hydraulic shovel and the like. As well as the reliability and safety, it is possible to improve the reliability and safety.

On the other hand, the insertion hole 41A at the position of each recess 42A
Is formed to be larger than the outer diameter Dp of the pusher 13A so that each gap G is located at the position of the resistance ring 40A between the guide cylinder 31A and the pusher 13A.
Therefore, the oil liquid supplied between the guide cylinder 31A and the pusher 13A from the inside of the casing 1 flows toward the seal ring 44A from the resistance ring 40A through the gaps G. It can be reliably distributed.
Therefore, the space between the pusher 13A and the guide cylinder 31A can be maintained in a lubricated state from the inside of the casing 1 to the position of the seal ring 44A, and it is possible to reliably suppress wear of both.

Further, since the guide cylinder 31A is formed separately from the casing 1 and the pusher 13A is slid in the guide cylinder 31A fixed to the casing 1, the guide cylinder 31A is separated from the casing 1. In the detached state, the resistance ring 40A and the seal ring 44A can be easily attached to the small guide cylinder 31A.
By attaching the guide tube 31A to the guide tube mounting hole 6A of the casing 1 with the A and the pusher 13A provided, the resistance ring 40A and the seal ring 44A are provided.
And the like, the assembling work on the casing 1 side can be made much more efficient.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted. And
However, a feature of the resistance ring 51 according to the present embodiment is that concave portions 54, 54,... Are formed on the outer peripheral surface 53 side of the resistance ring 51.

Here, similarly to the first embodiment, the resistance ring 51 is formed in an annular shape having an insertion hole 52 from an elastic resin material such as urethane rubber, for example. A plurality of substantially V-shaped recesses 54, 54,... Are formed on the outer peripheral surface 53 side of each other, and convex portions 55, 55,.

The resistance ring 51 is connected to the guide cylinder 31A.
While being inserted in the resistance ring groove 34A (34B) of (31B), the insertion hole 52 (inner peripheral surface) is pushed into the pusher 13A.
The sliding resistance is given to the pusher 13A (13B) by making the sliding contact with the (13B) elastically. Also,
At this time, at the position of each recess 54 on the outer peripheral surface 53,
A gap is formed between the bottom surface of the casing 4 and the bottom surface of the resistance ring groove 34A (34B).
The oil liquid is supplied from the inner side toward the protruding end side of the pusher 13A (13B).

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as in the first embodiment can be obtained.

Next, FIG. 6 shows a third embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted. And
However, the feature of the resistance ring 61 according to the present embodiment is that the oil through holes 63, 63,... Are formed.

Here, as in the first embodiment, the resistance ring 61 is formed of an elastic resin material such as urethane rubber or the like, and is formed in an annular shape having an insertion hole 62 at the center. A plurality of oil holes 63, 63, 63,... Which are located around the insertion hole 62 and penetrate from the front side to the rear side.
Is formed on the resistance ring 61.

Thus, also in the present embodiment having the above-described structure, it is possible to obtain substantially the same operation and effect as those of the first and second embodiments.

In each of the above embodiments, the resistance ring 40
A, 40B, 51, and 61 have guide cylinders 31A (3
1B) is mounted in the resistance ring groove 34A (34B), and the insertion holes 41A (41B), 52, and 62 are pushed into the pusher 13A.
(13B), but the present invention is not limited to this, and the groove width of the resistance ring groove 34A (34B) is formed sufficiently larger than the axial dimension of the resistance rings 40A, 40B, 51, 61. By doing so, the insertion hole 41A (41
B), the outer peripheral sides of the resistance rings 40A, 40B, 51, 61 attached to the pushers 13A (13B) via the 52, 62 are brought into sliding contact with the bottom surfaces of the resistance ring grooves 34A (34B),
This may be configured to provide sliding resistance to the pusher 13A (13B).

In the first and second embodiments, the resistance rings 40A (40B) and 51 are formed from an elastic resin material such as urethane rubber. However, the present invention is not limited to this. 40B) and 51 are formed from, for example, a wear-resistant metal material or the like, and the insertion holes 41A (41
B), the pusher 13A (13)
B), the pusher 13A (13)
A configuration may be adopted in which sliding resistance is applied to B).

Further, in each of the above embodiments, the case where the pressure reducing valve type pilot valve is used as the pilot hydraulic power source of the hydraulic shovel has been described as an example. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention may be applied to a machine, or may be applied to a pilot hydraulic system of an industrial machine other than a construction machine.

[0062]

As described in detail above, according to the first aspect of the present invention, a plurality of grooves are provided between the casing and the pusher.
Or a resistance ring having an oil passage hole is provided , and the resistance ring is slid in contact with a pusher sliding in the casing with an appropriate sliding resistance. When the lever is intentionally operated, the pusher can be reliably slid in the casing against the sliding resistance, and if the operation lever is erroneously tilted due to external vibration or the like, the pusher is pushed. Pressing operation (sliding displacement) can be reliably prevented by the sliding resistance. Therefore, it is possible to reliably prevent the pusher from being pressed by a slight tilting force erroneously applied to the operation lever, and to prevent the pressure-reducing valve-type pilot valve from malfunctioning. Properties can be reliably improved. A groove or an oil passage hole provided in the resistance ring;
Oil fluid along the sliding direction of the pusher
By circulating, the oil liquid in the casing is pushed
Around the pusher and the casing between the pusher and the casing.
Keeping the moving surface in a lubricated state and suppressing the occurrence of wear, etc.
Can be.

According to the second aspect of the present invention, since the pusher is configured to slide within the guide cylinder provided in the casing, the resistance ring and the sealing member can be removed with the guide cylinder removed from the casing. Can be easily mounted on a small guide cylinder, and by attaching a guide cylinder provided with a resistance ring, a seal member and a pusher to the casing, the work of assembling the resistance ring, seal member, etc. to the casing can be greatly improved. Efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a pressure reducing valve type pilot valve according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part such as a guide cylinder and a pusher in FIG.

FIG. 3 is a plan view showing a resistance ring according to the first embodiment of the present invention.

FIG. 4 is a sectional view of the resistance ring shown in FIG. 3;

FIG. 5 is a plan view showing a resistance ring used in a pressure reducing valve type pilot valve according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a resistance ring used in a pressure reducing valve type pilot valve according to a third embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a pressure reducing valve type pilot valve according to the related art.

[Explanation of symbols]

 Reference Signs List 1 casing 3 pump port 4 tank port 9A, 9B output port 11A, 11B spool 13A, 13B pusher 16A, 16B setting spring 17 operating lever 19 cam 31A, 31B guide cylinder 40A, 40B, 51, 61 resistance ring (resistance member) 42A, 54 recesses 44A, 44B seal ring (seal member) 63 oil through hole G gap

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-294281 (JP, A) JP-A 7-22186 (JP, U) JP-A 3-39602 (JP, U) 22730 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F15B 13/042 F16K 31/44 F16K 35/04

Claims (2)

(57) [Claims] 1. A spool having a pump port, a tank port, and an output port, a spool slidably provided in the casing, and communicating the output port with one of the pump port and the tank port, and the spool. One end side is slidably inserted into the casing, and the other end side is disposed between the pusher and the spool, and the push operation amount of the pusher is displaced. A setting spring for setting the pressure on the output port side by the spool in accordance with the operation lever, and an operation lever having a cam abutting on a protruding end side of the pusher for pressing the pusher against the setting spring. A pressure-reducing valve-type pilot valve comprising: a pusher that slides between the casing and the pusher in response to a push operation of the pusher. A given anti-, and該Pu
A plurality of grooves which hydraulic fluid to the sliding direction of Ssha allows you to distribution or
Others a resistance ring having a through oil holes, that hydraulic fluid inside than the resistance ring located in the projecting end toward the pusher the casing is provided with a sealing member for sealing the leakage to the outside Characteristic pressure reducing valve type pilot valve. 2. A casing, which comprises a part of the casing and guides the pusher in a slidable manner, wherein the resistance ring is provided between the guide cylinder and the pusher.
The pressure reducing valve type pilot valve according to claim 1, wherein the pressure reducing valve type pilot valve is configured to dispose a ring and a seal member.