KR101946926B1 - Oil pressure adjustment valve with prevention function of spool driving reisistance - Google Patents

Abstract

The configuration of the present invention includes a case (3) having a discharge passage (14) and at least one supply passage (12); at least one spool (8) inserted in the case (3) so as to be longitudinally movable through the supply passage (12) and the discharge passage (14) to regulate the flow of the working oil; a spool hole (18) is provided in the case (3) so as to guide reciprocating (5GD) of the spool (8) in the longitudinal direction and communicated with or disconnected from the discharge passage (14) by the longitudinal reciprocating motion of the spool (8); a pushing cam (10) connected to an upper side of the case (3) through a joint (2JT)(2) and performing a see-saw motion with respect to the joint (2JT)(2); a lever (1) connected to the pushing cam (10) to perform a see-saw motion on the pushing cam (10) as a result of operation thereof and reciprocating the spool (8) in the spool hole (18) to open and close the supply passage (12) with respect to the discharge passage (14); a bypass space (20) provided in the case (3) and communicating with the spool hole (18) where the spool (8) is lifted and lowered to bypass the working oil remaining between the spool (8) and the spool hole (18) when the spool (8) is pressed to prevent an interference pressure when the spool (8) is lowered; and a bush (30) provided with a hydraulic oil space (32), the hydraulic oil space (32) being embedded in the case (3) by communicating with the bypass space (20) through a hydraulic oil pass hole (34).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hydraulic pressure control valve,

The present invention relates to a hydraulic control valve having a spool operation resistance preventing function, and more particularly, to a hydraulic control valve with a spool operation resistance preventing function of a new configuration capable of reducing a resistance when a spool is pushed and reducing friction with a valve inner wall surface The present invention relates to a hydraulic control valve.

  Generally, a hydraulic operation system is provided with an actuator such as a hydraulic motor or a hydraulic cylinder, and a hydraulic operation valve is provided for controlling the direction and flow rate of the fluid supplied to the actuator to control the operation of the actuator.

Such a hydraulic control valve may have various structures depending on the hydraulic system. For example, the hydraulic control valve may be used in various heavy equipment such as an excavator for operation of a driving drive unit, boom, arm, bucket, or turning of a vehicle.

In the conventional hydraulic control valve, the pushing cam is moved in a seesaw motion by means of an operation stick or a mechanical operation means operated by an operator such as a pedal in some cases to press down the spools on both sides, and the lowered spool is returned upward by the springs And the flow of the working fluid through the internal flow path is controlled according to the movement of the spool.

In the hydraulic control valve, a spool chamber is formed in a lower portion of the valve housing to insert a lower end of the spool while the spool is moved. As the spool moves, hydraulic oil flows into the spool chamber, The back pressure is caught and the operation of the spool can not be properly performed. Therefore, a means for preventing this is required.

However, conventionally, when the spool is depressed, the resisting force due to the hydraulic pressure (operating oil) is relatively large, which makes it difficult to operate the hydraulic control valve. In addition, in the prior art, only one side of the spool is formed with an internal flow path, so that when the spool is pushed and the hydraulic oil is discharged, the spool is discharged only in one direction. .

Korean Patent Publication No. 1998-087734 (published on December 5, 1998) Domestic registered patent No. 10-0803963 (registered on February 11, 2008)

It is an object of the present invention to reduce the manufacturing cost by simplifying the structure so that the operating fluid remaining in the spool chamber can be discharged through the existing flow path provided inside the valve and is easy to install and maintain, Which is capable of reducing the resistance of the valve body and reducing the friction between the valve body and the inner wall surface of the valve.

According to an aspect of the present invention, there is provided a vacuum cleaner comprising: a case having a discharge passage, a discharge passage and a port therein; At least one spool inserted into the case longitudinally movably through the supply passage and the discharge passage to adjust the flow of the hydraulic fluid; A spool hole provided in the case and guided to reciprocate the spool in a longitudinal direction, the spool hole being communicated with or disconnected from the discharge passage by longitudinal reciprocation of the spool; A pushing cam connected to an upper side of the case via a joint and performing a seesaw motion based on the joint; A lever connected to the pushing cam to seesaw the pushing cam according to the operation, reciprocates the spool in the spool hole to open / close the supply passage with respect to the discharge passage; And a spool which is provided inside the case and communicates with the spool hole in which the spool moves up and down to thereby bypass the operating fluid staying between the spool hole and the spool when the spool is pressed, A bypass space for preventing an overheating phenomenon; And a bush installed in the case to communicate with the bypass space through a hydraulic oil pass hole. The hydraulic control valve according to claim 1, Is provided.

Wherein a plurality of spool holes are arranged radially with respect to a central portion of the case and the bypass space is formed in a lower side of the case so that the spool holes and the bypass space are communicated with each other, And the spool is movably coupled to the spool hole.

 The bypass space is formed in a pulley shape on the lower end side of the spool disposed in the radial direction with respect to the center of the case.

The case is detachably connected to a lower cap at a lower portion thereof, and the bypass space is formed between a front surface of the space forming cap provided below the case and an upper surface of the lower cap.

The case is provided with a bushing hole to be vertically and coaxially aligned with the lower cap, a lower end of the bushing hole communicates with the bypass space, a bushing is coupled to the bushing hole, And a hydraulic oil passage hole communicating the bypass space and the hydraulic oil space is provided at a lower end of the bush.

Wherein the bush has a threaded portion on an outer circumferential surface thereof, the bush hole formed in the case has a threaded portion on an inner circumferential surface thereof, a tool groove is formed in a lower end portion of the bush, The bush is inserted into the bush connection hole by the screw portions, and the lower cap is coupled to the lower cap engagement hole.

A threaded portion is formed on an inner peripheral surface of the lower cap engagement hole and a threaded portion is formed on an outer peripheral surface of the lowered cap so that the lower cap is bolted to the lower cap engagement hole by the threaded portions.

And the lower end of the lower cap is provided with a tool groove.

Wherein a spool passage for communicating the bypass space and the discharge passage is formed in the spool.

Wherein the delivery passage includes a center feed passage extending along the longitudinal direction from the center portion of the spool to the inside of the spool; And a plurality of balance oil drains extending in the radial direction from the center oil channel.

The present invention reduces the resistance force when the spool is depressed due to the oil pressure of the bypass space being drawn into the discharge passage through the oil passage inside the spool when the spool is pressed, The oil pressure in the bypass space is released through the oil passage, thereby further reducing the resistance force when the spool is pressed, thereby further improving the operation of the spool. It is possible to reduce the resistance force when the spool is pressed by the oil passage which is the oil passage inside the spool and to further reduce the resistance force when the spool is pressed by adding the oil hydraulic oil pass hole and the oil hydraulic oil space to the bush, have.

1 is a sectional view of a hydraulic control valve according to the present invention;
Figure 2 is an enlarged cross-sectional view of the main part of Figure 1
Fig. 3 is a sectional view showing the operating state of the main part shown in Fig. 2
4 (a) is a view schematically showing the operating state of the spool which is a main part of the conventional hydraulic pressure control valve
4 (b) is a view conceptually showing the operating state of the spool which is a main part of the hydraulic pressure control valve according to the present invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. For example, if a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, It is to be understood that other components may be "connected "," coupled "

Referring to the drawings, a hydraulic control valve having a function of preventing the spool 8 from being operated according to the present invention is provided with a plurality of (at least two or four) spools 8 And operating means for reciprocating the spool 8 up and down. The operating means includes a push rod 5 mounted on the upper portion of each spool 8, a pushing cam 10 pushing the push rod 5 inwardly of the case 3, And a spring (13). The present invention includes a spool hole 18 in which the spool 8 is operated to move up and down and a bypass space 20 provided below the spool hole 18 and below the spool hole 18. In addition, the present invention includes a hydraulic oil pass hole 34 for communicating the bypass space 20 of the case 3 with the hydraulic oil space 32 therein as main characteristic components. At this time, the present invention can be applied to a common working machine or a hydraulic system having a hydraulically actuated actuator such as an excavator, a hydraulic motor, and a hydraulic cylinder.

The case 3 has a structure in which a supply passage 12 connected to an external hydraulic pump and an actuator is provided at an inner lower side and a discharge passage 14 connected to an external hydraulic oil tank is provided at an upper side thereof, A connecting flow path 16 is formed between the supply flow path 12 and the discharge flow path 14 in which the spool 8 is movably inserted and the lower end of the spool 8 is connected to the lower side of the connecting flow path 16, A spool hole 18 into which a part of the spool hole 18 is inserted is formed. Although not shown, the supply passage 12 is formed with a pump port connected with a hydraulic pump, and the discharge passage 14 is formed with a tank port connected to a working oil tank.

The push rod 5 has a lower end portion connected to each spool 8 and an upper end portion projecting to the outside of the case 3 so as to be vertically movable by a guide 5GD in the shape of a single pipe. An annular support plate 5SP is provided at a connection portion of the spool 8 and the spring 13 is installed inside the discharge passage 14 to support the support plate 5SP upward.

The pushing cam 10 is connected to the center of the upper side of the case 3 by a joint 2JT (which may be a universal joint 2JT if necessary) And is arranged so as to be rotatable in a soothing manner. The pushing cam 10 pushes the upper portion of the push rod 5 protruding outward from the pivotal center (i.e., the joint 2JT). A connecting shaft 10TR having a threaded portion on the outer circumferential surface is provided at the upper side center portion of the pushing cam 10 and a screw portion is provided on the lower end side outer peripheral surface of the lever 1 disposed above the pushing cam 10, The lever 1 is connected to the pushing cam 10 by a nut 2 which is commonly coupled to the threaded portion of the lever 1 and the threaded portion of the connecting shaft of the pushing cam 10. A screw hole is formed in a central portion of the pushing cam 10 and a connecting shaft having a threaded portion on the outer circumferential surface is provided at the center of the upper surface of the joint 2JT so that the outer circumferential surface thread portion of the connecting shaft of the joint 2JT is pushed And a screw portion of the outer circumferential surface of the lever 1 and a screw portion of the outer circumferential surface of the lever 1 are integrally fixed to the screw 10 of the cam 10, So that the lever 1 and the pushing cam 10 are connected to each other.

The spool 8 has a conventional structure in which a diameter enlarged portion is formed at a predetermined interval so as to open or close the connection flow path 16 between the supply flow path 12 or the supply flow path 12 and the discharge flow path 14. The spool 8 is inserted into the case 3 so as to be longitudinally movable through the supply passage 12 and the discharge passage 14 to regulate fluid flow between the hydraulic pump, the actuator and the hydraulic oil tank, 3 are provided with a plurality of spools 8 on the basis of the central portion thereof. In the present invention, four spools (8) are provided with respect to the center of the case (3).

In the embodiment of the present invention, the supply passage 12 is formed in a pipe shape, the discharge passage 14 is formed in a room shape, and two flow paths, that is, two supply paths 12, However, the present invention is not limited to this, and it is natural that the present invention can be applied to a conventional valve having the supply passage 12 and the discharge passage 14 in various forms and positions.

In the embodiment of the present invention, the pushing cam 10 and the spring 13 are exemplified as actuating means for causing the spool 8 to reciprocate, And can be made of various structures for exercising.

The spool hole 18 is formed in the case 3 so as to allow the spool 8 to reciprocate in the longitudinal direction by a guide 5GD. And is vertically formed inside the case 3 so as to be raised and lowered relative to each other in the vertical direction. The case 3 is provided with the connecting passage 16 so as to be disposed above the spool hole 18 and the bypass space 20 is provided so as to extend to the spool chamber 19 at the lower end of the spool hole 18 . The connection passage 16 is opened or closed in accordance with the reciprocating movement of the spool 8 so that the supply passage 12 and the discharge passage 14 are connected or closed.

The case 3 is configured such that a discharge passage 14 is provided at an upper position of the interior of the spool hole 18. And the exhaust passage 14 is provided at the upper position of the connection passage 16 precisely. The spool hole 18 is provided above the discharge flow passage 14 and is provided with a guide hole 5GH which meets directly above. The lower end of the guide hole 5GH communicates with the discharge passage 14 and the upper end thereof communicates with the upper side of the case 3. [ A guide 5GD is provided in the guide hole 5GH and the push rod 5 is relatively slidably engaged with the guide 5GD. The upper end of the spool 8 is fixed to the lower end of the push rod 5, The push rod 5 is pushed in accordance with the seizing motion of the pushing cam 10 and the spool 8 is pushed down when the push rod 5 is pushed, The flow path between the flow path 14 and the supply flow path 12 can be opened.

The present invention comprises bypass space (20). The bypass space 20 is provided inside the case 3 and communicates with the spool chamber 19 provided at the lower end of the spool hole 18 in which the spool 8 ascends and descends, The working fluid staying between the spool hole 18 and the spool 8 is bypassed to prevent the interference pressure when the spool 8 is lowered. To this end, a plurality of spool holes 18 are radially arranged around the center of the case 3, and a bypass space 20 is formed inside the lower side of the case 3. A bypass space 20 is formed in the case 3 so as to communicate with the spool chamber 19 provided at the lower end of the spool 8 and the lower end of the spool hole 18 at the lower side of the case 3 will be. A lower end of each spool hole (18) formed in the case (3) communicates with the bypass space (20). At this time, the bypass space 20 may be configured as a pool having a wide space. The bypass space 20 may be formed in a plow shape so as to communicate with the lower end of the spool hole 18 arranged in the radial direction with respect to the center of the case 3. Since the bypass space 20 is formed in a pool shape ensuring a wide space, it is more advantageous for the interference pressure operating oil to be released from the spool chamber 19, It can be said that it is more preferable that it is formed in a pulley shape. In the present invention, a plurality of spool holes 18 are provided in the case 3 in the radial direction with respect to the center of the spool hole 18. A lower end of the spool 8, which is vertically coupled to the spool hole 18, A spool chamber 19 is provided between the lower end of the spool chamber 19 and the spool chamber 19 so that the operating oil normally enters the spool chamber 19, And has a structure in which the bypass spacer is formed on the inner lower side of the substrate 3. And a bypass space 20 of a wide room shape is disposed so as to communicate with the lower portion of each of the spool holes 18. [

The case 3 is detachably coupled to a lower portion of the case 3 so that a bypass space is formed between the front surface of the space forming cap provided at the lower side of the case 3 and the upper surface of the lower cap 22, (20). The lower cap 22 is coupled to the lower cap coupling hole formed at the center of the bottom surface of the case 3. A screw portion is formed on the inner circumferential surface of the lower cap engagement hole and a screw portion is formed on the outer circumferential surface of the lower cap 22 so that the lower cap 22 is bolted to the coupling hole of the lower cap 22 by the screw portions. . ≪ / RTI > At this time, the lower end of the lower cap 22 is provided with a tool groove. The tool groove may be a lancet groove or a deep groove groove. When the lancet is coupled to the lancet groove or the driver is coupled to the driver groove, the lower cap 22 is rotated by a wrench or a screwdriver, The lower cap 22 can be coupled to the lower cap engagement hole of the lower cap 22.

A bush 30 is provided in the case 3. The bush 30 is provided with a hydraulic oil space 32 therein and a hydraulic oil pass hole 34 communicated with the hydraulic oil space 32 is provided at a lower end of the bush 30.

A bushing 30 is provided in the case 3 so as to be vertically and horizontally aligned with the lower cap 22. The lower end of the bushing 30 is in communication with the bypass space 20, A bush 30 is coupled to the bush 30 and a hydraulic oil space 32 is provided in the bush 30 and a bypass space 20 and a hydraulic oil space Hydraulic oil pass holes 34 for communicating the hydraulic oil passages 32 are provided.

The bush 30 is provided with a threaded portion on the outer circumferential surface thereof. The bush 30 coupling hole formed in the case 3 is provided with a threaded portion on the inner circumferential surface thereof, and a tool groove is provided on the lower end portion of the bush 30 The bush 30 is inserted into the inside of the case 3 through the lower cap engagement hole formed at the lower end of the case 3 and disposed inside the bypass space 20, And is bolted to the bushing hole by the screw portions. At the lower end of the bush 30, a tool groove is provided. The tool groove may be a lancet groove or a deep groove groove. In the state where the lancet is coupled to the lancet groove of the bush 30 or the driver is coupled to the driver groove, the bush 30 is rotated by a wrench or a screwdriver, So that it can be engaged with the bushing hole in the case 3. Next, the lower cap engagement hole is coupled with the lower cap 22, so that a downwardly opened hole in the bypass space 20 blocks the lower cap engagement hole.

The overall operation of the flow control valve of the present invention constructed as described above is similar to that of the conventional one. That is, when the operator pushes or pulls the lever 1 to pivot the pushing cam 10, the push rod 5 selectively pushed down causes the spool 8 connected to the lower portion to descend, The spool 8 is returned upward by the spring 13 and the hydraulic pressure is supplied to the spool 8 through the supply passage 12 and the discharge passage 14 in accordance with the position of the spool 8. [ The direction and flow rate of the hydraulic fluid supplied between the pump, the actuator, and the hydraulic oil tank are adjusted, thereby operating the bucket and the like of the excavator.

The bypass space 20 prevents the spool 8 from interfering with the operation of the spool 8. As the operator grips the lever 1 and operates the pusher cam 10 in a seesaw motion The push rod 5 is pushed and the spool 8 is lowered by the push rod 5 being pressed. The lower end of the spool 8 descends while the spool 8 descends. When the lower end of the spool 8 descends downward, the spool 8 between the inner bottom surface of the case 3 and the lower end of the spool 8, The hydraulic pressure (operating oil) received in the spool 8 is depressed and the hydraulic pressure (operating oil) pressed by the spool 8 falls into the bypass space 20 formed in the wide room shape below the spool 8, When the hydraulic pressure is discharged (bypassed) to the bypass space 20, the pressure action due to the residual hydraulic pressure (residual operating oil) in the spool 8 is not generated. The spool 8 smoothly descends without being disturbed by the operation.

In this case, in the present invention, a bush 30 is built in the case 3 so as to be disposed above the bypass space 20. A hydraulic oil space 32 is secured in the bush 30, The hydraulic oil space 32 in the hydraulic oil passage 30 is configured to communicate with the bypass space 20 through the hydraulic oil pass hole 34. [

Therefore, when the spool 8 is pressed, the hydraulic pressure (working oil) remaining in the spool chamber 19 and the hydraulic pressure (working oil) in the bypass space 20 are transmitted through the hydraulic oil pass hole 34, (Resisting force due to the residual oil pressure) when the spool 8 is pushed as it enters the hydraulic oil space 32 in the spool valve 30, so that the spool 8 can be operated more smoothly . The residual hydraulic pressure (residual operating fluid) is smoothly discharged and the operation of the spool 8 is further smoothened by adding the bush 30 which is a structure for internally discharging the residual hydraulic pressure as compared with the prior art. Further, It is effective.

In the present invention, the spool (8) is provided with an oil return passage (9) for communicating the bypass space (20) and the discharge flow passage (14). The oil discharge passage (9) And a plurality of balance oil feed passages 9BH.

The center discharge passage 9CH extends in the longitudinal direction from the center of the spool 8 to the inside of the spool 8. [ The center discharge passage 9CH extends from the lower end of the spool to the inside of the spool 8 by a predetermined length.

The base end of the balance drainage passage 9BH is connected to the center drainage passage 9CH and the tip end of the balance drainage passage 9BH communicates with the outer peripheral surface of the spool 8. [ A plurality of balance oil feed passages 9BH are radially arranged with respect to the center of the center feed passage 9CH.

Therefore, when the spool 8 is pushed, the hydraulic pressure (working oil) filled in the bypass space 20 is raised through the center discharge passage 9CH, and a plurality of radially arranged The oil is discharged into the discharge passage 14 in a uniform amount through the balanced oil passage 9BH. Therefore, when the spool 8 is pushed, the discharge of the hydraulic oil is balanced so that the oil can smoothly move without friction.

The oil supply passage 9 (internal oil passage) is formed so as to communicate with only one side of the spool 8 so that the oil is discharged only in one direction when the spool 8 is pushed and the hydraulic oil is discharged. Is tilted so that unilateral friction appears between the spool 8 and the wall surface of the spool hole 18, which may adversely affect the performance of the hydraulic control valve. 4 (a).

In the present invention, since the drainage passage 14 is formed in various directions (four directions) to allow hydraulic oil discharge to be balanced when the spool 8 is pushed, the tilt of the spool 8 does not occur, Since the spool 8 smoothly moves without any one-side friction between the wall surface of the spool hole 18 and the wall surface of the spool hole 18, the effect of adversely affecting the performance of the hydraulic pressure control valve can be prevented.

In the present invention, the bush 30 is provided with a threaded portion, the threaded portion is provided on the inner circumferential surface of the coupling hole of the bush 30 of the case 3, and a tool groove is provided on the lower end of the bush 30 So that the bush 30 can be inserted through the lower cap coupling hole communicated from the lower side of the case 3 to the lower side of the case 3, It is possible to separate the bush 30 from the bushing hole separately, so that a better result can be expected from various aspects such as maintenance. 4 (b).

The specific embodiments of the present invention have been described above. It is to be understood, however, that the scope and spirit of the present invention is not limited to these specific embodiments, and that various modifications and changes may be made without departing from the spirit of the present invention. If you have, you will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

1. Lever 2. Nut
2JT. Joint 3. Case
5. Push rod 8. Spool
9. 9CH with oil. Center drainage
9BH. Balanced oiling 10. Pushing cam
12. Supply flow 13. Spring
14. Discharge channel 16. Connection channel
18. Spool hole 19. Spool chamber
22. Lower cap 30. Bush
32. Hydraulic oil space 34. Hydraulic oil pass hole

Claims (10)

A case 3 in which a supply passage 12, a discharge passage 14 and a port are provided;
At least one spool (8) inserted in the case (3) so as to be longitudinally movable through the supply passage (12) and the discharge passage (14) to regulate the flow of the working oil;
The spool 8 is provided in the case 3 so as to be reciprocated in the longitudinal direction by a reciprocating motion guide 5GD and is communicated with or disconnected from the discharge passage 14 by a longitudinal reciprocating motion of the spool 8. [ A spool hole 18;
A pushing cam 10 connected to an upper side of the case 3 via a joint 2JT and performing a seesaw motion with reference to the joint 2JT;
The pushing cam 10 is connected to the pushing cam 10 so that the pushing cam 10 is seated and the spool 8 is reciprocated in the spool hole 18 so that the supply path 12 is connected to the discharge path 14 for opening and closing the lever 1;
The spool hole 18 communicates with the spool hole 18 which is provided in the case 3 and in which the spool 8 ascends and descends. When the spool 8 is pushed, A bypass space 20 for bypassing the operating fluid remaining between the spool 8 and the spool 8 to prevent an interference pressure when the spool 8 is lowered;
A hydraulic oil space 32 is provided in the case 3 and the hydraulic oil space 32 has a bush 30 built in the case 3 to communicate with the bypass space 20 through a hydraulic oil pass hole 34 Including,
A plurality of spool holes 18 are radially arranged with respect to a central portion of the case 3 and the bypass space 20 is formed in a lower side of the case 3, (18) is connected to the bypass space (20), the spool (8) is movably coupled to the spool hole (18)
Wherein the bypass space (20) is in the form of a pulley at the lower end side of the spool (8) arranged in the radial direction with respect to the center of the case (3). The spool valve.
delete delete The method according to claim 1,
The case 3 is detachably connected to a lower cap 22 at a lower portion of the case 3 so as to be positioned between the front face of the space forming cap provided at the lower side of the case 3 and the upper face of the lower cap 22, (20) is formed on the inner circumferential surface of the valve body (20).
5. The method of claim 4,
In the case 3, a bush hole 30 is provided so as to be vertically and horizontally aligned with the lower cap 22. The lower end of the bush hole is communicated with the bypass space 20, A hydraulic oil space 32 is provided in the bush 30 and the bypass space 20 and the hydraulic oil space 32 are connected to the lower end of the bush 30. The bush 30, And a hydraulic oil passage hole (34) communicating with the hydraulic oil passage hole (34).
6. The method of claim 5,
The bush 30 is provided with a threaded portion on the outer circumferential surface thereof. The bush 30 coupling hole formed in the case 3 is provided with a threaded portion on the inner circumferential surface thereof, and a tool groove is provided on the lower end portion of the bush 30 The bush 30 is inserted through a lower hole 22 formed at the lower end of the case 3 so that the bush 30 can be bolted to the bush 30 through the threaded portions, And the lower cap (22) is coupled to the lower cap (22) coupling hole.
The method according to claim 6,
A threaded portion is formed on the inner circumferential surface of the lower cap engagement hole and a threaded portion is formed on the outer circumferential surface of the lower cap 22. The lower cap 22 is inserted into the coupling hole of the lower cap 22 by the threaded portions. Wherein the valve body is configured to engage with the valve body in a bolt-coupled manner.
8. The method of claim 7,
And a tool groove is provided at a lower end of the lower cap (22).
The method according to claim 1,
Wherein the spool (8) is provided with an oil drain passage (9) for communicating the bypass space (20) with the discharge flow passage (14).
10. The method of claim 9,
The discharge passage (9)
A center discharge passage (9CH) extending in the longitudinal direction from the center of the spool (8) to the inside of the spool (8);
And a plurality of balance oil feed passages (9BH) extending in the radial direction from the center oil feed passage (9CH).

Images