JP2000136802A - Pressure reducing valve type pilot valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure reducing valve type pilot valve capable of creating an oil groove in a pusher without needing chamfering machining of a curved surface or inside face machining of an inside of a hole. SOLUTION: An operating lever 26 is swung, a pusher 16 is pressed by means of a cam 23, and a spool 13 is slid by means of a pressure setting spring 19. Oil grooves to make a cylindrical part 16A of the above pusher 16 smoothly slide within a sliding hole 30 includes spiral grooves 16C and 16D, both of which have the same width and are symmetric with respect to an axis 60 of the cylindrical body 16A any cut in height position and along diametrical direction and grooves are positioned on a straight line including axis center. These spiral grooves 16C and 16D are formed in an outer surface of the cylindrical body 16A by means of a lathe with a specified tool, conducting feeding operation in an axial direction of the cylindrical body 16A and rotating operation.

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 suitable for use in, for example, switching control of a direction control valve in a main circuit for driving an actuator.

[0002]

2. Description of the Related Art In recent years, in construction machines and civil engineering machines,
With an increase in size, speed, and performance, the hydraulic circuit is complicated, and the flow rate of hydraulic oil flowing in the hydraulic circuit is also increasing. In order to easily and smoothly perform switching control of the direction control valve of these hydraulic circuits and tilt control of the variable displacement pump, for example, a pressure reducing valve type pilot valve as described in JP-A-9-189301 is employed. ing.

[0003] Here, this type of prior art pressure reducing valve type pilot valve has a pump port, a tank port, and an output port, and has a casing having a spring chamber therein. A spool slidably provided in the casing for communication with any one of the above, and having a distal end extending into the spring chamber; and a pusher provided on the casing and operated to push and displace the spool. A spring seat provided at the distal end of the spool so as to be movable in the axial direction and pushed by a pusher; and a spring seat located between the spring seat and the spool, provided in a spring chamber, and output in response to a push operation of the pusher. A pressure setting spring for setting a discharge pressure from the port; and a return spring located between the spring seat and the casing and provided in the spring chamber.

[0004] In this pressure reducing valve type pilot valve, when the pusher is pushed, the spool is slid downwardly via the pressure setting spring, and the output port and the pump port communicate with each other. Then, the pressure oil from the hydraulic pump is discharged to the output port. At this time, the high pressure of the output port acts on the spool, and the spool slides upward against the elastic force of the pressure setting spring to make the output port communicate with the tank port. Then, when the pressure at the output port decreases, the spool is slid downward by the pressure setting spring, and the output port and the tank port communicate again.

In this way, while the spool repeatedly slides and displaces the output port so that the output port communicates with one of the pump port and the tank port, the discharge pressure from the output port increases with the spring load of the pressure setting spring. The balance is balanced so that the pressure of the pressure oil discharged from the output port is controlled according to the operation amount of the pusher.

As another prior art, for example, Japanese Utility Model Application Laid-Open No. Sho 58-66410 discloses a spool provided with a large diameter portion and a small diameter portion, and a hydraulic pressure is provided between the end surface of the large diameter portion of the spool and the casing. There is disclosed a pressure reducing valve type pilot valve configured to form a chamber and communicate between the hydraulic chamber and an output port via an oil passage provided in a spool.

In this conventional pressure reducing valve type pilot valve, the pressure of the output port is applied to the hydraulic chamber through the oil passage, so that the pushing operation force on the pusher can be reduced.

Further, as another prior art, for example, in Japanese Patent Application Laid-Open No. 7-55048, a pusher is provided with a rod portion and a cylindrical portion connected to the rod portion and accommodating a spring seat. A pilot valve is disposed between a cylindrical portion and a casing, and two linear oil grooves having a uniform width along the axial direction are formed at positions opposed to each other across the axis of the cylindrical portion. Have been.

The oil groove may be formed by chamfering the outer peripheral surface of the cylindrical portion of the pusher, or may be provided with a recess having a semicircular cross section on the sliding surface of the casing on which the cylindrical portion of the pusher slides. It is formed as described above.

In the pressure reducing valve type pilot valve in which the oil groove is formed as described above, when the pusher slides in the casing, a gap formed between the upper end surface of the cylindrical portion and the casing, The space located between the lower side and the casing communicates. As a result, the pressure oil moves between the space and the space through the oil groove.

In this way, when the space is expanded and compressed due to the vertical displacement of the pusher, the resistance is small and the pusher can smoothly slide on the casing.

When the oil groove is formed by forming a chamfer on the outer peripheral surface of the cylindrical portion of the pusher in the above-mentioned oil groove, the cylindrical portion may be provided with an oil groove in advance in consideration of ease of manufacture. It can be made by casting. However, when made by casting, errors in the width dimension between the two oil grooves and misalignment of the cylindrical portion with respect to the axis are likely to occur. Therefore, in such a case, it is common to first form a cylindrical portion, and then perform machining to make two chamfers on the outer peripheral surface of the cylindrical portion. Similarly, in the case where an oil groove consisting of two depressions having a semicircular cross section is formed on the sliding surface of the casing on which the cylindrical portion of the pusher slides, first, the casing is made, and then the cross section is semicircular. Usually, machining is performed to form an oil groove composed of two depressions.

In any case of the above-described oil groove formed by two chamfers and the oil groove formed by two depressions having a semicircular cross section, a width error occurs between the two oil grooves. If the pusher slides and the pressure oil passes through the oil groove, the pressure of each of the two oil grooves Due to the oil, the magnitudes of the forces pushing the cylindrical portion of the pusher toward the axis differ from each other, or the direction in which the cylindrical portion is pushed does not coincide with the axis of the cylindrical portion, thereby causing either one of the cylindrical portions. The peripheral side is pressed strongly against the casing,
For this reason, the pusher may not be slid smoothly.

[0014]

In the above-mentioned prior art, two chamfers are applied to the outer peripheral surface of the cylindrical portion of the pusher with the axis of the cylindrical portion interposed therebetween so as to shift the position of the uniform width to each other. In the machining that creates a linear oil groove that does not occur, the outer peripheral surface of the curved surface is gradually flattened to cut out a predetermined width dimension at a predetermined position, and the cylindrical portion of the pusher slides. In machining which forms a linear oil groove consisting of two depressions having a semicircular cross section so as to face each other across the axis of a hole forming a sliding surface of a moving casing, the sliding surface of the casing is used. That is, since an oil groove having a predetermined width is cut at a predetermined position on an inner peripheral surface of a hole formed in the casing, extremely careful and difficult work is required in each case. Therefore, there is a problem that a large amount of work time and labor is required in the above-described conventional technology.

The present invention has been made in consideration of the above-described circumstances in the prior art, and has an object to form an oil groove in a pusher portion without requiring chamfering of a curved surface or inner working of a hole. It is to provide a pressure reducing valve type pilot valve.

[0016]

In order to achieve the above-mentioned object, the invention according to claim 1 comprises a casing having a pump port, a tank port and an output port, and having a spring chamber therein, and the output port. A large-diameter portion for communicating with the pump port and the tank port is provided slidably in the casing, and a small-diameter portion located at a tip of the large-diameter portion extends into the spring chamber. A pusher provided on the casing and pushed to slide the spool, and a spring seat provided axially movably on the small diameter portion of the spool and pushed by the pusher. , Provided between the spring seat and the spool in the spring chamber,
A pressure setting spring for setting a discharge pressure from the output port in accordance with a pushing operation of the pusher, and a return spring provided between the casing and a spring seat and provided in the spring chamber. The pusher has a rod portion that is pushed and operated, and a cylindrical portion that is connected to the rod portion and houses the spring seat, and an outer peripheral surface of the cylindrical portion has an upper end surface of the cylindrical portion. And a space formed between the casing and the lower side of the cylindrical portion and the casing, and a pressure for smoothly performing the sliding operation of the pusher with respect to the casing. In a pressure reducing valve type pilot valve in which an oil groove through which oil passes is formed, the oil groove includes a first spiral groove and a second spiral groove having uniform groove widths, and these first spiral grooves And the second helical groove with the cylinder Even when cut along the radial direction at any height position, the first spiral groove and the second spiral groove on the cut surface face each other so as to sandwich the axis of the cylindrical portion. The first helical groove, the axis of the cylindrical portion, and the second helical groove are formed so as to have a positional relationship of being located on a straight line.

According to the first aspect of the present invention, when the pusher slides in the casing, a gap formed between the upper end surface of the cylindrical portion of the pusher and the casing and the lower portion of the cylindrical portion are formed. A space located between the side and the casing communicates via an oil groove. The pressurized oil moves between the space and the space through the oil groove. Thereby, the axial resistance generated at the time of the expansion / compression operation of the air gap due to the vertical displacement of the pusher is reduced, and the pusher can be smoothly slid in the casing.

When the pressure oil passes through the oil groove, the first
Pressure oil passing through the helical groove and the second helical groove, even when the cylindrical portion is cut along the radial direction at any height position,
The pressure oil passing through the first spiral groove on the cut surface and the second oil
Pressure oil passing through the helical groove of the cylindrical portion opposes the axis of the cylindrical portion, and passes through the first helical groove, the axis of the cylindrical portion, and the second helical groove. Pressure oil is located on a straight line, the force applied by the pressure oil from each of the first spiral groove and the second spiral groove toward the axis of the cylindrical portion is opposite to each other, In addition, since the pressure receiving areas are equal, the pressure receiving areas have the same size and are offset. Thereby, the axis of the cylindrical portion of the pusher substantially coincides with the axis of the hole of the casing in which the cylindrical portion slides, that is, one of the peripheral side surfaces of the cylindrical portion of the pusher slides in the casing. The cylindrical portion can be smoothly slid within the casing without being pressed against the surface.

In forming the above-described oil groove, the first
The oil groove including the spiral groove and the second spiral groove is easily formed by a lathe that cuts the outer peripheral surface of the cylindrical portion with a predetermined tool while performing an axial feeding operation and a rotating operation of the cylindrical portion. can do. This makes it possible to easily form a highly accurate oil groove without the need for chamfering a curved surface or processing the inner surface of a hole.

According to a second aspect of the present invention, in the first aspect, a plurality of combinations of the first spiral groove and the second spiral groove are provided.

According to a third aspect of the present invention, in the first or second aspect, the oil groove has the same positional relationship as the first spiral groove and the second spiral groove. It is characterized by including a third spiral groove and a fourth spiral groove which are oppositely wound to the first spiral groove and the second spiral groove.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pressure reducing valve type pilot valve according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a pressure reducing valve type pilot valve of the present invention, FIG. 2 is a perspective view showing a pusher provided in the embodiment shown in FIG. 1, and FIG. Exploded view showing an oil groove formed in the cylindrical portion of the pusher shown in FIG.
FIG. 4 is a sectional view taken along line XX of the pusher shown in FIG.

The present embodiment is applied to a hydraulic pilot operating device of a hydraulic shovel, for example, and is configured as follows. That is, as shown in FIG.
Inside, a pump port 5 connected to the hydraulic pump 4,
It has a tank port 7 connected to the tank 6 and an output port 8 connected to a directional control valve (not shown).

A spool sliding hole 9 in which a spool 13 having a large-diameter portion 14 and a small-diameter portion 15 slides is provided in the casing 1. The spool sliding hole 9 is connected to the output port 8. It is open. The spool 13 is slid and displaced by pushing a pusher 16 described later.

The sliding hole 9 for the spool has an upper part opening in a spring chamber 11 described later and a recess 10 formed therein. A hydraulic chamber 21 is formed between the recess 10 and the spool 13. It is. The hydraulic chamber 21 has a spool 1
3 slides in the sliding hole 9 for the spool.
3, a downward pressure is always applied.

The spool slide hole 9 is provided so as to be orthogonal to the pump port 5 and the tank port 7, and the large diameter portion 14 of the spool 13 is slidably provided. By sliding in the spool sliding hole 9, one of the tank port 5 and the pump port 7 communicates with the output port 8.

The large diameter portion 14 of the spool 13 communicates with the oil passage 14A extending in the axial direction and penetrates the oil passage 14A in the radial direction of the large diameter portion 14. An oil hole 14B communicating with one of the tank ports 7 is formed. An oil passage 22 that connects the output port 8 and the hydraulic chamber 21 is formed above the oil passage 14 </ b> A in the large diameter portion 14. The outer peripheral surface near the upper part of the large-diameter portion 14 where the opening of the oil passage 22 is located is for guiding the pressure oil sent from the oil passage 22 to the hydraulic chamber 21.
The diameter is set smaller by a predetermined dimension.

The small-diameter portion 15 of the spool 13 is provided at the upper end of the large-diameter portion 14 and extends to a spring chamber 11 described later. The hydraulic chamber 2 is provided above the sliding hole 9 for the spool.
1 to form the recess 10 of the sliding hole 9 for the spool.
Is formed. A connecting portion extends from the upper end of the hydraulic chamber forming portion 15A, and a guide shaft portion 15B for guiding the sliding of the spool 13 via the connecting portion is continuously provided. A head 15C is provided at the tip of the guide shaft 15B.

The above-mentioned hydraulic chamber 21 is provided with the concave portion 10 of the above-described spool sliding surface 9 and the large-diameter portion 14 of the spool 13.
Between the upper end surface of the hydraulic chamber forming portion 15A of the spool 13
Is formed in an annular shape around.

The spring chamber 11 in which the small-diameter portion 15 of the spool 13 extends is configured as follows. That is, a stepped disk-shaped spring seat 17 is provided on the guide shaft portion 15B of the small diameter portion 15 of the spool 13 so as to be able to reciprocate in the axial direction of the guide shaft portion 15B. It is locked. A pressure setting spring 19 is arranged on the outer peripheral side of the small diameter portion 15 of the spool 13,
It abuts on the step inside the spring seat 17 and is locked. On the outer peripheral side of the pressure setting spring 19, a return spring 20 is arranged,
The spring seat 17 is engaged with the outer step and locked.

The lower end of the pressure setting spring 19 abuts and is locked by an annular spring receiving plate 18 provided on the upper end surface of the hydraulic chamber forming portion 15A of the spool 13. Return spring 20
Of the spool 13 protruding from the concave portion 10 in the casing 1 abuts and is engaged with a spring seat surface 12 provided on the outer peripheral side of the hydraulic chamber forming portion 15A of the spool 13.

The pressure setting spring 19 thus arranged
Is to generate a spring load in accordance with the pushing operation amount of the pusher 16, and to set the pressure discharged from the output port 8 by the spring load. The return spring 20 is set to have a lower elastic force than the pressure setting spring 19, and
3 is always urged upward through the spring seat 17. The spring chamber 11 is configured as described above.

The pusher 16 for slidingly displacing the spool 13 is provided so as to protrude from the upper part of the casing 1 and always contact the cam 23. The pusher 16 is pushed by the cam 23 and has a rod 16B. A cylindrical portion 16A is provided which is connected to the rod portion 16B, is formed in a cylindrical shape, and is slidably provided in the pusher sliding hole 30.

A pusher 16 is provided on the outer peripheral surface of the cylindrical portion 16A.
And a gap formed between the upper end surface of the cylindrical portion 16A and the casing 1 when sliding, and a pusher sliding hole 30 located between the lower side of the cylindrical portion 16A and the casing 1.
Are formed, for example, a first spiral groove 16C and a second spiral groove 16D.

As shown in FIG. 2, the first spiral groove 16C has one end wound from the position 40a on the edge of the lower end face of the cylindrical portion 16A to the right in the paper of FIG. The other end is located at a position 40 on the edge of the upper end surface of the cylindrical portion 16A. Also, the second spiral groove 16D is wound in the same direction as the first spiral groove 16C, that is, as shown in FIG.
When the position 40b on the edge of the lower end surface of the cylindrical portion 16A where one end is disposed is viewed from the back side of the paper, the upper end is wound up to the right and the other end is the edge of the upper end surface of the cylindrical portion 16A. It is arranged at the upper position 40C. These first spiral grooves 16
C, the respective groove widths of the second spiral groove 16D are uniformly formed with each other.

That is, even if the first spiral groove 16C and the second spiral groove 16D are cut along the radial direction at any height position of the cylindrical portion 16A as shown in FIG. Certain first spiral groove 16C and second spiral groove 16D are cylindrical portion 1
As shown in FIG. 4, the first spiral groove 16C, the second spiral groove 16D, and the axial center 60 of the cylindrical portion 16A are located on a straight line. That is, the first
The spiral groove 16C and the second spiral groove 16D have a cylindrical portion 16A.
The outer peripheral surface of the cylindrical portion 16A is cut at an arbitrary position on the outer peripheral surface of the cylindrical portion 16A, for example, a position 40 and a position 40a shown in FIG. In the developed view shown in FIG. 3, they are alternately arranged in parallel at equal intervals. Then, as shown in FIG.
An arbitrary position 40d on C and the cylindrical portion 1
Each of the positions 40e on the second helical groove facing each other with the axis 60 of 6A interposed therebetween is located at the same height from the lower end surface of the cylindrical portion 16A. That is, as shown in FIG. 3, the position 40d on the first helical groove 16C and the position 40e on the second helical groove 16D are mutually cylindrical.
A is located at the same height L from the lower end face of A.

The first spiral groove 16 configured as described above
C and the second spiral groove 16D are formed by a lathe that cuts the outer peripheral surface of the cylindrical portion 16A with a predetermined tool while performing the feeding operation and the rotating operation of the cylindrical portion 16A.

As shown in FIG. 1, the cam 23, which is always in contact with the rod 16B of the pusher 16, is
It is provided via a universal joint 24 which is arranged and fitted on the upper part of the casing 1. An operation rod 26 is attached to the universal joint 24 via a nut 25. By tilting the operation rod 26, the rod 16 </ b> B is pushed through the cam 23.

The casing 1 is provided with a pump port 5,
The main body casing 2 is provided with the tank port 7 and the output port 8 and the like, and the lid side casing 3 is provided with the pusher 16 and the spring seat 17 and the like. That is, any position between the spring seat surface 12 provided on the main body side casing 2 and the spring seat 17 provided on the lid side casing 2, for example, the upper end face 2 </ b> B of the main body side casing 2
And it is formed so as to be dividable at the position of the lower end surface 3A of the lid side casing 3. The main body side casing 2 and the lid side casing 3 are assembled with bolts or the like (not shown).

An annular seal member 27 is provided between the main casing 2 and the lid casing 3, and an annular seal member 28 is provided between the lid casing 3 and the pusher 16. I have.

A relief valve 29 for setting the primary pressure of the hydraulic pump 4 is provided between the tank 6 and the pump port 5.

In this embodiment configured as described above,
When the operating rod 26 is tilted, the pusher 16 is pushed through the cam 23. Thereby, the pusher 16
Is displaced downward.

Accordingly, the cylindrical portion 16A of the pusher 16
Pressure oil in the pusher sliding hole 30 on the lower side of the pusher 16 passes through the first spiral groove 16C and the second spiral groove 16D of the cylindrical portion 16A of the pusher 16, passes through the upper end surface of the cylindrical portion 16A of the pusher 16 and the casing. 1 is led to the gap formed between the first and second cavities.

At this time, the pressure oil passing through the first spiral groove 16C and the second spiral groove 16D exerts a force in the radial direction of the cylindrical portion 16A. That is, the pressure oil passing through an arbitrary position on the first helical groove 16C and the second helical groove 16D facing the straight line including the axis 60 with the axis 60 interposed between the arbitrary positions. Respectively, and acts on the pressure receiving areas equal to each other, thereby generating forces in directions opposite to each other and toward the axis of the cylindrical portion 16A. The two forces generated in this way are equal in magnitude and in opposite directions and cancel each other out. For example, as shown in FIGS. 2 and 3 described above, the first spiral groove 16C
Pressure oil passing through the upper position 40d and the second spiral groove 16D
Each of the pressure oil passing through the upper position 40e is
It faces on a straight line including this axis 60 with 0 interposed. Forces in directions opposite to each other act from each of these positions 40d and 40e in the axial direction of the cylindrical portion 16A. And, as described above, the first spiral groove 16C,
Since the second spiral groove 16D is formed with a mutually uniform groove width, the positions 40d and 40e have the same area,
Accordingly, the pressure oil exerts an equal amount of force at each of the position 40d and the position 40e, and these forces cancel each other. As described above, the force acting in the radial direction of the cylindrical portion 16 by the pressurized oil is canceled out, and the cylindrical portion 16A maintains the balance of the radial force, that is, the axial center 60 of the cylindrical portion 16A is connected to the sliding hole 30 for the pusher. Of the pusher sliding hole 3
It slides smoothly within 0.

Further, the pressure oil moves from the pusher sliding hole 30 located below the cylindrical portion 16A to the space formed between the upper end surface of the cylindrical portion 16A and the casing 1. The resistance in the axial direction to the pusher 16 generated when the airbag expands is reduced. Thereby, the pusher 16 slides smoothly.

As described above, when the pusher 16 is displaced downward, the spool 13 is displaced downward via the pressure setting spring 19. The spool 13 shuts off the output port 8 and the tank port 7 and connects the output port 8 with the pump port 5. Then, the hydraulic pump 4
The pressure by the pressure oil sent from the pump port 5 is discharged from the pump port 5 to the output port 8 through the oil hole 14B and the oil path 14A of the spool 13 and the sliding hole 9 for the spool.

When the pressure is discharged to the output port 8, an upward pressure acts on the spool 13 by the pressure oil in the output port 8. This pressure causes the spool 13 to be displaced upward while compressing the pressure setting spring 19. And
The spool 13 shuts off the output port 8 and the pump port 5 and connects the output port 8 with the tank port 7. At this time, the pressure oil is discharged from the output port 8 through the sliding hole 9 for the spool, through the oil path 14A and the oil hole 14B of the spool 13, and to the tank port 7. Thereby, the pressure of the output port 8 decreases, and the spool 13
It is displaced downward by the pressure setting spring 19. And
The output port 8 and the pump port 5 are communicated again.

As described above, while the spool 13 repeats reciprocating motion, the pressure of the output port 8 is increased by the pressure setting spring 19.
Will be balanced with the spring load. At this time, the pressure of the output port 8 is controlled by generating a spring load in accordance with the pushing operation amount of the pusher 16 by the pressure setting spring 19.

The pressure oil is supplied from the output port 8 to the oil passage 14.
A and the inside of the hydraulic chamber 21 through the oil passage 22. A part of the pressure of the output port 8 acts on the hydraulic oil in the hydraulic chamber 21 through the oil passage 14A of the spool 13 through the oil passage 22 at all times. This allows
The upward pressure acting on the spool 13 from the output port 8 is offset by the pressure acting downward on the spool 13 from the hydraulic chamber 21.

As described above, according to the present embodiment, the first spiral groove 16C and the second spiral groove 16D provided on the outer peripheral surface of the cylindrical portion 16A of the pusher 16 and having a uniform groove width.
No matter which height of the cylindrical portion 16A is cut along the radial direction, the first spiral groove 16C and the second
The spiral groove 16D faces the axis portion 60 of the cylindrical portion 16A so as to sandwich the axis 60. As shown in FIG. 4, the first spiral groove 16C, the second spiral groove 16D, and the axis 60 of the cylindrical portion 16A. Since it is formed on a straight line, the balance of the radial force of the cylindrical portion 16A of the pusher 16 is maintained, and the pusher 16 can slide smoothly.

The first helical groove 16C and the second helical groove 16D are provided with a pusher sliding hole 30 located between the lower side of the cylindrical portion 16A and the casing 1 and the upper end surface of the cylindrical portion 16A. By communicating with a gap formed between the casing 1 and the casing 1, the axial resistance to the pusher 16 generated when the gap is expanded and compressed can be reduced. Thereby, the pusher 16 can be slid smoothly.

Further, as described above, the first helical groove 16C and the second helical groove 16D allow the outer peripheral surface of the cylindrical portion 16A to be fixed while performing the axial feed operation and the rotation operation of the cylindrical portion 16A. It is formed using a lathe that cuts with a tool. Accordingly, the oil groove can be easily formed without the need for chamfering the outer peripheral surface of the cylindrical portion 16A, that is, the curved surface, and the inner surface processing for the pusher sliding hole 30. Therefore, the manufacturing operation of the pusher 13 is started. Time and effort can be reduced.

It should be noted that the cylindrical portion of the cylindrical portion 16A and the oil grooves 16C and 16D can be manufactured using the same lathe. Thus, the time required for the operation of manufacturing the pusher 16 can be further reduced.

Further, since the casing 1 is formed so as to be divided between the spring seat surface 12 provided on the main body casing 2 and the spring seat 17 provided on the lid casing 2, the pressure setting spring 19 and the return Spring 20, spool 1
Regardless of the length of 3 or the like, the small diameter portion 15 of the spool 13 assembled to the main body side casing 2 can be projected outside the main body side casing 2. As a result, the pressure setting spring 19, the return spring 20, the spring seat 17 and the like do not need to be assembled in the casing 1, and a large space can be secured and can be easily performed. Work efficiency can be improved.

The spool 13 and the sliding hole 9 for the spool
A hydraulic chamber 21 for applying a hydraulic pressure downward to the spool 13 is formed between the hydraulic chamber 21 and the recess 10 so that the pressure oil of the output port 8 is introduced into the hydraulic chamber through the oil passage, and the pressure in the hydraulic chamber 21 is reduced. Always acts on the end face of the large diameter portion 14 of the spool 13. Thereby, the force required for the pushing operation on the pusher 13 can be reduced. Therefore, the pusher 13 can be pushed and operated with a relatively small force, and the pressure reducing valve type pilot valve can be downsized.

In the above-described embodiment, FIGS.
A pair of the first spiral groove 16C and the second spiral groove 16 shown in FIG.
D, but the present invention is not limited to this, and the first spiral groove 16C and the second spiral groove 16C are not limited thereto.
As long as the same positional relationship as D is satisfied, a plurality of combinations of the first spiral groove and the second spiral groove may be provided. For example, as shown in FIG. 5, in addition to the first spiral groove 16C and the second spiral groove 16D described above, the first spiral groove 16C and the second spiral groove 16D are located at different positions, for example, at different positions. 40
f, 40g, the first spiral groove 16C and the second spiral groove 16C.
A first spiral groove 16 having the same groove width and positional relationship as D
E and the second spiral groove 16F may be provided.

Also, as shown in FIG.
4 in addition to the first spiral groove 16C and the second spiral groove 16D, the first spiral groove 16C and the second spiral groove 16D
Third spiral groove 16G made of reverse winding in the same positional relationship as
And a fourth spiral groove 16H, that is, a third spiral groove 16G wound up to the left from the position 40b with respect to the plane of FIG. , The fourth spiral groove 1 wound upward to the left from the position 40a
6H may be provided.

Also, as shown in FIG.
In addition to the first spiral groove 16C and the second spiral groove 16D, the angle of the spiral wound between the first spiral groove 16C and the second spiral groove 16D is different, and the first spiral groove 16C and the second spiral groove 16D have different spiral angles. 2
The first spiral groove 16J and the second spiral groove 16K having the same positional relationship as the spiral groove 16D of the above, that is, the spiral having the uniform groove width and being wound from the position 40a upward to the right with respect to the sheet of FIG. When viewed from the groove 16J and the back side of the paper,
A spiral groove 16K that is wound upward and to the right from the position 40b may be provided.

Further, in the above-described embodiment, the case where the casing 1 is divided into the main body side casing 2 and the lid side casing 3 has been described. However, the present invention is not limited to this. At least one of the casing 2 and the lid-side casing 3 may be composed of a plurality of divided bodies, and a casing that can be divided into three or more as a whole may be applied.

In the above-described embodiment, the pressure reducing valve type pilot valve in which two spools 13 and the like are provided in the casing 1 has been described as an example. However, the present invention is not limited to this. For example, one or three in the casing
The present invention may be applied to a pressure reducing pilot valve provided with more than one spool.

[0062]

As described above, according to the present invention, the oil groove formed on the outer peripheral surface of the cylindrical portion is formed by the first spiral groove and the second spiral groove having uniform groove widths. And is formed by a lathe that cuts with a predetermined tool while performing a feed operation in the axial direction of the cylindrical portion and a rotation operation. Accordingly, a highly accurate oil groove can be formed more easily than before without the need for chamfering a curved surface or processing the inner surface of a hole, thereby reducing the time and labor required for the pusher manufacturing operation as compared with the conventional case. be able to.

Further, the cylindrical portion of the cylindrical portion and the oil groove can be manufactured by using the same lathe, and in the case of using the same lathe, the cylindrical portion and the oil groove are connected by a series of operations. , And the time and labor required for the pusher manufacturing operation can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a pressure reducing valve type pilot valve of the present invention.

FIG. 2 is a perspective view showing a pusher provided in the embodiment shown in FIG.

FIG. 3 is a development view showing an oil groove formed in a cylindrical portion of the pusher shown in FIG.

4 is a sectional view of the pusher shown in FIG. 2 taken along line XX.

FIG. 5 is a perspective view showing a first example of a pusher constituting another embodiment of the pressure reducing valve type pilot valve of the present invention.

FIG. 6 is a perspective view showing a second example of a pusher constituting another embodiment of the pressure reducing valve type pilot valve of the present invention.

FIG. 7 is a perspective view showing a third example of a pusher constituting another embodiment of the pressure reducing valve type pilot valve of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Body side casing 2A Cylindrical hole 2B Upper end surface 3 Lid side casing 3A Lower end surface 4 Hydraulic pump 5 Pump port 6 Tank 7 Tank port 8 Output port 9 Spool sliding hole 10 Depression 11 Spring chamber 12 Spring seat 13 Spool 14 Large diameter portion 14A Oil path 14B Oil hole 15 Small diameter portion 15A Hydraulic chamber forming portion 15B Guide shaft portion 15C Head 16 Pusher 16A Cylindrical portion 16B Rod portion 16C First spiral groove 16D Second spiral groove 16E First Spiral groove 16F Second spiral groove 16G Third spiral groove 16H Fourth spiral groove 16J First spiral groove 16K Second spiral groove 17 Spring seat 18 Spring receiving plate 19 Pressure setting spring 20 Return spring 21 Hydraulic pressure Chamber 22 Oil passage 23 Cam 24 Universal joint 25 Nut 26 Operating rod 29 Relief valve for setting primary pressure 30 Pusher sliding hole 40 position 40a position 40b position 40c position 40d position 40e position 40f position 40g position 60 Shaft center

Continued on the front page F term (reference) 2D003 AA01 CA02 EA00 3H056 AA09 BB33 BB50 CA03 CB03 CB06 CD02 CE10 FF01 GG04 GG12 3H081 AA01 BB14 CC20 DD34 EE18 HH01 3H089 AA60 BB30 DB76 JJ01

Claims (3)

[Claims] A casing having a pump port, a tank port, and an output port, and having a spring chamber therein, and a large-diameter portion for communicating the output port with one of the pump port and the tank port. A spool slidably provided in the casing, and a small-diameter portion located at a tip of the large-diameter portion extends into the spring chamber;
A pusher provided on the casing and operated to push and displace the spool, a spring seat provided on the small diameter portion of the spool so as to be movable in the axial direction, and pushed by the pusher; A pressure setting spring provided between the casing and the spring seat, the pressure setting spring being provided between the spool and the spool, and setting a discharge pressure from the output port in accordance with a pushing operation of the pusher. And a return spring provided in the spring chamber and the pusher includes a rod portion that is pushed and operated, and a cylindrical portion that is connected to the rod portion and houses the spring seat. The outer peripheral surface of the cylindrical portion communicates a space formed between the upper end surface of the cylindrical portion and the casing, and a space located between the lower side of the cylindrical portion and the casing, Said In a pressure-reducing valve type pilot valve in which an oil groove through which pressure oil passes to smoothly perform a sliding operation of a pusher with respect to the casing, the oil groove includes a first spiral groove having a uniform groove width. A second spiral groove, and the first spiral groove and the second spiral groove are on the cut surface of the cylindrical portion at any height position along the radial direction when cut along the radial direction. The first spiral groove and the second spiral groove face each other so as to sandwich the axis of the cylindrical portion, and the first spiral groove, the axial center of the cylindrical portion, the second spiral groove, Are formed so as to have a positional relationship located on a straight line. 2. A plurality of combinations of the first spiral groove and the second spiral groove are provided.
The pressure-reducing valve type pilot valve as described in the above. 3. The oil groove according to claim 1, wherein the oil groove is a first spiral groove and a second spiral groove.
And a third spiral groove and a fourth spiral groove which have the same positional relationship as that of the first spiral groove and which are oppositely wound to the first spiral groove and the second spiral groove. 3. The pressure reducing valve type pilot valve according to 1 or 2.