KR102086109B1 - Proportional pressure-reducing valve with spool having improved shape of land portion - Google Patents

Abstract

According to one embodiment of the present invention, a proportional pressure reducing valve, comprising: a cylindrical body having a predetermined diameter having a first end and a second end, and first to fourth lands spaced apart from each other with a diameter larger than the diameter of the body; A spool having a portion; A cylindrical shape having a cylindrical shape having an open first end and a second end, the cylindrical sleeve being coaxially aligned with the spool to surround the spool and having first to third through holes formed therein; An actuator coupled to the second end of the sleeve and capable of forcing a second end of the spool to move the spool in the sleeve; A housing having an inner space accommodating the sleeve and having first to third flow paths communicating with first to third through holes of the sleeve; And a spring interposed between the inner wall of the housing and the first end of the spool, wherein the first and second land portions of the spool open and close the first through hole of the sleeve and the fourth land portion of the spool The third through hole may be opened and closed, and the third land part disposed between the second land part and the fourth land part includes one or more grooves formed from one end to the other end of the third land part along a length direction on a surface thereof. Disclosed is a proportional pressure reducing valve.

Description

Proportional pressure-reducing valve with spool having improved shape of land portion

The present invention relates to a proportional pressure reducing valve, and more particularly, to a proportional pressure reducing valve having a spool and an actuator having an improved shape of a land portion, which is easy to manufacture, advantageous in miniaturizing the valve, and also improves control precision. .

In general, industrial equipment such as excavators, cranes, forklifts, and the like have a hydraulic system for driving the equipment, which includes an electronic proportional pressure reducing valve for controlling the working fluid pressure in the system. Proportional pressure reducing valve is a valve that can obtain a secondary control pressure proportional to the electromagnetic force generated in the actuator having a solenoid coil, the main components and operation principle is, for example, Korean Patent Laid-Open No. 1999-0010175, 2014-0010251 and the like.

By the way, the main component of the conventional proportional pressure reducing valve (spool) is formed of a cylindrical body and a plurality of lands (land) of a larger diameter than this body, it was not easy to manufacture a conventional spool. In addition, in the case of the conventional proportional pressure reducing valve, since the electromagnetic force generated in the solenoid actuator is not symmetrical with respect to the central axis, the plunger cannot be precisely controlled, and thus the flow rate of the valve cannot be precisely controlled.

Patent Document 1: Korean Patent Publication No. 2014-0010251 (published January 24, 2014)

The present invention has been made to solve the above problems, by providing a spool and actuator having an improved shape of the land portion to provide a proportional pressure reducing valve that is easy to manufacture, advantageous in miniaturizing the valve, and also improves the control precision For the purpose of

According to one embodiment of the present invention, a proportional pressure reducing valve, comprising: a cylindrical body having a predetermined diameter having a first end and a second end, and first to fourth lands spaced apart from each other with a diameter larger than the diameter of the body; A spool having a portion; A cylindrical shape having a cylindrical shape having an open first end and a second end, the cylindrical sleeve being coaxially aligned with the spool to surround the spool and having first to third through holes formed therein; An actuator coupled to the second end of the sleeve and capable of forcing a second end of the spool to move the spool in the sleeve; A housing having an inner space accommodating the sleeve and having first to third flow paths communicating with first to third through holes of the sleeve; And a spring interposed between the inner wall of the housing and the first end of the spool, wherein the first and second land portions of the spool open and close the first through hole of the sleeve and the fourth land portion of the spool The third through hole may be opened and closed, and the third land part disposed between the second land part and the fourth land part includes one or more grooves formed from one end to the other end of the third land part along a length direction on a surface thereof. Disclosed is a proportional pressure reducing valve.

According to the proportional pressure reducing valve according to an embodiment of the present invention as described above, by removing the protrusion of the tip of the spool and engaging the spring to the groove of the tip, it is possible to miniaturize the valve, the land to guide the movement of the spool By forming the cylindrical portion and forming a groove through which the fluid passes, the ease of manufacturing the spool compared to the conventional land portion can be improved.

In addition, according to an embodiment of the present invention, by forming a plurality of drains on the flange of the actuator, each drain is disposed in a position symmetrical with respect to the central axis to form a magnetic field symmetrical about the central axis to precisely control the valve flow rate There is an advantage in improving sex.

1 is an exploded perspective view of a proportional pressure reducing valve according to an embodiment of the present invention;
2 is a side cross-sectional view of a proportional pressure reducing valve according to one embodiment;
3 and 4 are views for explaining the spool according to the first embodiment;
5 and 6 are views for explaining the spool according to the second embodiment;
7 is a view for explaining a flange according to one embodiment, and
8 is a view for explaining the technical effect of the flange according to an embodiment.

Objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art.

In the drawings of the present specification, the length, thickness, width, etc. of the components may be exaggerated for the effective description of the technical content.

In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the words "comprise" and / or "comprising" do not exclude the presence or addition of one or more other elements.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In describing the specific embodiments below, various specific details are set forth in order to explain the invention in more detail and aid in understanding. However, one of ordinary skill in the art can understand that the present invention can be used without these various specific details. In some cases, it is mentioned in advance that parts of the invention which are commonly known in the description and which are not highly related to the invention are not described in order to avoid confusion in describing the invention.

1 is an exploded perspective view of a proportional pressure reducing valve according to an embodiment of the present invention, Figure 2 is a side cross-sectional view of the proportional pressure reducing valve.

Referring to the drawings, the proportional pressure reducing valve according to one embodiment may include a housing 10, an actuator 20, a sleeve 300, and a spool 40. As shown in Fig. 2, the housing 10 may be a plurality of pressure reducing valves. A block of hexahedron having an inner space for accommodating the sleeve 30, and a plurality of flow paths may be formed therein. In the illustrated embodiment, the housing 10 includes first to third flow paths 101, 102, and 103, which will be described later. As will be appreciated, each of these flow paths 101, 102, 103 is configured to communicate with the first through third through holes 301, 302, 303 of the sleeve 30, respectively.

In one embodiment, the first flow path 101 may be connected to the fluid tank for supplying the fluid, the second flow path 102 may be connected to the cylinder, and the third flow path 103 may be connected to the storage tank where the fluid is returned. Fluid is supplied to the cylinder through the second flow path 102 in the first flow path 101 to operate the cylinder, or the fluid of the cylinder is stored through the third flow path 103 in the second flow path 102. You can return to the tank.

The actuator 20 is coupled to one end of the sleeve 30 and may apply a force to the spool 40 such that the spool 40 disposed inside the sleeve 30 moves within the sleeve 30. In one embodiment, the actuator 20 may include a case 210, a flange 220, a plunger 230, and a piston rod 240. The case 10 is a cylindrical housing member surrounding the plunger 230 and including a solenoid coil therein. The flange 220 is interposed between the sleeve 30 and the case 210 to couple the case 210 and the sleeve 30. The plunger 230 may be a cylindrical member and may reciprocate in the case 10 by electromagnetic force. The piston rod 240 is coupled to one end of the plunger 230.

The piston rod 240 penetrates the flange 220 and protrudes out of the flange 220 and is configured such that an end of the piston rod 240 contacts the spool 40 disposed in the sleeve 30. The first spring 120 interposed between the spool 40 and the end and the inner wall of the housing 10 is disposed on the left side of the spool 40, and the plunger 230 and the case 210 are disposed on the right side of the plunger 230. The second spring 215 interposed therebetween is disposed, and the plunger 230, the piston rod 240, and the spool 40 are supported by the elastic force of the first spring 120 and the second spring 215. It is becoming. Accordingly, when a current is applied to the solenoid coil, the plunger 230 and the piston rod 240 move to the left side (in FIG. 2) by electromagnetic force to push the spool 40 to the left side, and the current supply applied to the solenoid coil If stopped, the plunger 230 and the piston rod 240 may move to the right to return.

The sleeve 30 is a cylindrical member having an open first end and a second end. The sleeve 30 is arranged coaxially with the spool 40 to surround the spool 40, and a plurality of through holes may be formed on the surface of the sleeve 30. In the illustrated embodiment, the sleeve 30 includes first to third through holes 301, 302, 303. Each of the first to third through holes 301, 302, 303 of the sleeve 30 is formed at a position in communication with each of the first to third flow paths 101, 102, 103 of the housing 10.

The spool 40 is a member disposed inside the sleeve 30 and capable of reciprocating left and right by the operation of the actuator 20. 3 and 4, the spool 40 according to the first embodiment will now be described.

Referring to the drawings, the spool 40 is formed of a cylindrical body 400 having a predetermined diameter having a first end 401 and a second end 402, and a material having a diameter larger than the diameter of the body and spaced apart from each other. The first to fourth land portions 410, 420, 430, and 440 are provided. In one embodiment, the diameters of the first to fourth land portions 410, 420, 430, and 440 may be the same as the inner diameter of the sleeve 30.

As shown in the drawing, the surface of the first land portion 410 may include one or more grooves 411 along the circumference of the land portion 410. The groove 411 may be filled with fluid while the spool 40 is fitted inside the sleeve 30, and the fluid filled in the groove 411 may be lubricated when the spool 40 moves in the sleeve 30. Can be. In one embodiment, the body 400 and the first to fourth land portions 410, 420, 430, and 440 may be integrally manufactured. In an alternative embodiment, the body 400 and the land portions may be separately manufactured and then combined.

In the illustrated embodiment, the first land portion 410, the second land portion 420, the third land portion 430, in the direction from the first end 401 to the second end 402 of the spool 40, And the fourth land portion 440 are sequentially disposed. The width or the separation distance of each land portion 410, 420, 430, 440 may vary depending on the formation position of the through holes 301, 302, 303 of the sleeve 30. In an embodiment, the first through hole 301 of the sleeve 30 is positioned between the first land portion 410 and the second land portion 420, and the second land portion 420 and the fourth land portion 440 are located in the first land portion 410 and the second land portion 420. The second through hole 302 of the sleeve 30 is positioned between the second land openings 302, and the fourth land part 440 may overlap at least partially with the third through hole 303 of the sleeve 30. 410, 420, 430, and 440 are disposed. With this configuration, as the spool 40 reciprocates from side to side, the first and second land portions 410 and 420 of the spool 40 open and close the first through hole 301 of the sleeve 30 and the spool 40. The fourth land portion 440 of) may open and close the third through hole 303 of the sleeve 30.

The third land part 430 serves to guide the reciprocating motion of the spool 40. That is, while the spool 40 reciprocates in the sleeve 30, the central axes of the spool 40 and the sleeve 30 are guided to move in alignment. Accordingly, at least one groove 431 may be formed on the surface of the third land portion 430 to freely move the fluid in the space between the second land portion 420 and the fourth land portion 440 in the sleeve 30. Formed. The groove 431 is formed on the surface of the third land portion 430 from one end to the other end of the land portion 430 along the length direction, and thus, between the second land portion 420 and the fourth land portion 440. Fluid in the space may flow freely to the left and right of the third land portion 430 through the groove 431.

Although the illustrated embodiment shows four grooves 431 spaced at intervals of 90 degrees with respect to the central axis of the spool 40, this is exemplary, and according to a specific embodiment, one or a plurality of grooves 431 may have a third shape. It may be formed along the longitudinal direction at any position of the surface of the land portion 430.

Meanwhile, referring to FIGS. 2 to 4, the inside of the main body 400 of the spool 40 includes a first hole 404 formed in the longitudinal direction and a second hole 405 formed in the radial direction. The first hole 404 is opened toward the first end 401 of the spool body 400 and has a predetermined length in the longitudinal direction inside the body 400. The second hole 405 is formed in the radial direction inside the spool body 400 between the second land portion 420 and the fourth land portion 440 and communicates with the first hole 404.

In one embodiment, the inner wall of the housing 10 may further include a pin 110 installed to be partially inserted into the first hole 404 of the spool 40. One end of the pin 110 is inserted into the first hole 404 of the spool 30 and the other end is attached and fixed to the inner wall surface of the housing 10. The outer diameter of the pin 110 is equal to the inner diameter of the first hole 404 of the spool. Thus, for example, when the fluid is filled in the inner space of the sleeve 30, some of the fluid is also filled in the first hole 404 and the second hole 405, so that the pressure of the fluid is applied to one end of the pin 110.

The pin 110 partially fitted into the first hole 404 may also serve to guide the movement of the spool 40 while the spool 40 reciprocates from side to side within the sleeve 30. That is, since at least a portion of the pin 110 is inserted into the first hole 404 of the spool 40 while the spool 40 is moving, it is possible to prevent the spool 40 from deviating from the central axis and misaligning.

In one embodiment, the fin 110 may further include one or more grooves 111 formed along the circumference of the fin 110. When the valve is operated, the fluid is filled in the groove 111, and the fluid may serve as a lubrication when the spool 40 reciprocates.

Meanwhile, in the illustrated embodiment, an annular groove 403 is formed along the circumference of the end surface on the surface of the first end 401 of the spool 40. The annular groove 403 is for fitting the first spring 120. One end of the first spring 120 is fixed to the inner wall of the housing 10 and the other end is fitted into the annular groove 403 of the first end of the spool 40 so that the inner wall of the housing 10 and the spool It may be interposed between the 40.

As such, when the groove 403 is formed on the surface of the first end 401 of the spool and the first spring 120 is inserted into the groove 403 to be fixed, the length of the spool 40 can be reduced as compared with the related art. It has the effect of reducing the overall valve size. That is, conventionally, there was no groove 403, and a protrusion to which the spring 120 could be fitted was formed on the surface of the first end 401 of the spool. Therefore, since the total length of the spool 40 was as long as the protruding length of this protrusion, it hindered the miniaturization of the spool 40. However, according to the exemplary embodiment of the present invention, instead of removing the protrusion, a groove is formed on the surface of the first end 401 of the spool, and the first spring 120 is fitted into the groove to reduce the spool length. In addition, the spool 40 is not only supported by the first spring 120 but also the front end portion of the pin 110 installed on the inner wall of the housing 10 is inserted into the first hole 404 of the spool to move the spool 40. Since the protrusion is removed at the first end 401 of the spool, it is possible to prevent the spool 40 from deviating from the central axis of the sleeve 30 during the reciprocating motion.

The operation of the proportional pressure reducing valve according to the embodiment as described above will be briefly described.

If no current is applied to the solenoid coil of the actuator 20, the spool 40 is placed in a position as shown in FIG. 2 within the sleeve 30. That is, the first flow path 101 is located between the first and second land portions 410 and 420 of the spool 40, and the first flow path 101 is closed and the fluid flows toward the second flow path 102 (for example, to the cylinder side). Does not flow. A communication space is formed between the fourth land portion 440 of the spool 40 and the third through hole 303 of the sleeve 30, so that the cylinder-side fluid flows from the second flow passage 102 to the sleeve 30. As it flows into the interior space and exits along the third flow path 103, the cylinder-side hydraulic pressure may be lowered.

If electricity is applied to the actuator 20, an electromagnetic force is generated as current flows in the solenoid coil, and the plunger 230 and the piston rod 240 coupled thereto move to the left and push the spool 40 to the left. . Accordingly, when the spool 40 moves a predetermined distance to the left, the first flow path 101 is opened to communicate with the inner space of the sleeve 30, and the third flow path 103 is closed by the fourth land part 440. When the fluid is filled up to the second flow path 102, the pressure in which the fluid pushes the second land portion 220 of the spool to the left in the space in the sleeve 30 causes the pressure to push the fourth land portion 240 to the right. At this time, since there is an area difference between the second land portion 420 and the fourth land portion 440 as much as the cross-sectional area of the pin 110, a force is generated toward the fourth land portion 440, so that the spool 40 In this state, for example, the driver may control the actuator 20 (i.e., adjust the current strength applied to the solenoid coil) so that the spool 40 does not move to the right.

5 and 6 show a spool according to an alternative embodiment. Referring to the drawings, the spool 50 according to an alternative embodiment has a cylindrical body 500 of predetermined diameter having a first end 501 and a second end 502 and a diameter larger than the diameter of the body. The first to fourth land portions 510, 520, 530, and 540 are spaced apart from each other.

In the illustrated embodiment, the first land portion 510, the second land portion 520, the fourth land portion 540, in the direction from the first end 501 to the second end 502 of the spool 50, And the third land portion 530 are sequentially arranged. That is, the embodiment of FIG. 5 differs from the embodiment of FIG. 3 in that the third land portion 530 is disposed on the rightmost side in the drawing.

The shape, arrangement, and role of the first land portion 510, the second land portion 520, and the fourth land portion 540 are the first, second, and fourth land portions 410, 420, 440 of the embodiment of FIG. 3. Is the same as or similar to). That is, the first through hole 301 of the sleeve 30 is located between the first land portion 510 and the second land portion 520 of the spool 50, and the second land portion 520 and the fourth land portion are located. The second through hole 302 of the sleeve 30 is positioned between the 540 and the fourth land portion 540 is disposed so as to be at least partially overlapping with the third through hole 303 of the sleeve 30. As the spool 50 reciprocates left and right by this configuration, the first and second land portions 510 and 520 of the spool 50 open and close the first through hole 301 of the sleeve 30 and the spool 50. The fourth land portion 540 of the) may open and close the third through hole 303 of the sleeve 30.

The third land portion 530 serves to guide the reciprocation of the spool 50 and is located between the fourth land portion 540 and the second end 502 of the spool. The outer diameter of the third land portion 530 may be the same as the inner diameter of the sleeve 30 surrounding the third land portion 530. Alternatively, for example, if the third land portion 530 is surrounded by the interior of the cylindrical sleeve engaging portion 222 projecting in the direction of the sleeve 30 from the surface of the flange 220 as shown in FIG. The outer diameter of the third land portion 530 may be the same as the inner diameter of the sleeve coupling portion 222.

As such, the outer diameter of the third land portion 530 of the spool 50 is configured to be equal to the inner diameter of the region surrounding the third land portion 530 of the sleeve 30 or the actuator 20 so that the spool 50 is formed. When moving, the central axis of the spool 50 is not twisted and can be guided integrally with the central axis of the sleeve 30.

5 and 6 again, the third land portion 530 may include one or more through holes 531 or one or more grooves formed from one end to the other end of the third land portion 530 along the longitudinal direction. have. In the drawing, four through holes 531 are formed along the length direction of the third land part 530. However, the size or number of through holes 531 may vary according to specific embodiments. In addition, instead of the through hole 531, for example, one or more grooves formed in the longitudinal direction along the surface of the third land portion 530 may be formed in the third land portion 530, as shown in FIG. This through hole 531 or groove (not shown) allows fluid in the sleeve 30 to move freely between the fourth land portion 540 and the second end 502 of the spool 50.

Meanwhile, as shown in FIG. 6, grooves 507 of any shape may be formed in the surface of the second end 502 of the spool 50 according to an alternative embodiment. As the piston rod 240 reciprocates during the operation of the actuator 20, the end surface of the piston rod 240 and the surface of the second end 502 of the spool 50 continuously contact each other and generate noise. . However, as shown in the drawing, when the groove 507 is formed on the surface of the second end 502, some of the fluid inside the sleeve 30 is filled in the groove 507 during valve operation, and the filled fluid is spool 50. ) And the piston rod 240 in contact with the shock absorber to act as a shock absorber to reduce the noise and to improve the durability of the spool (50).

In the illustrated embodiment, two grooves 507 each formed in a substantially “C” shape and facing each other are illustrated, but the shape, number, and arrangement of the grooves 507 may vary according to specific embodiments.

7 is a schematic cross-sectional perspective view of the flange 220 as a view for explaining the flange according to an embodiment. Referring to the drawings, the flange 220 according to an embodiment is a disk-shaped flange body 221, a sleeve coupling portion 222 of a cylindrical shape protruding from the flange body 221 toward the sleeve 30, and The flange body 221 may include a case coupling portion 223 of a cylindrical shape protruding in the direction of the case 210 side.

A through hole 224 is formed in the central portion of the flange body 221 so that the piston rod 240 can pass therethrough, and a plurality of drains 225 are formed along the circumference of the through hole 224.

The plurality of drains 225 are configured to penetrate the flange body 221 parallel to the through hole 224 to serve to communicate between the inner space of the sleeve 30 and the inner space of the case 210. Accordingly, when the plunger 230 and the piston rod 240 reciprocate in the case 210, the fluid may freely move between the sleeve 30 and the inside of the case 210.

In this case, preferably, each drain of the plurality of drains 225 is formed at a position symmetrical with respect to the central axis of the flange 220. For example, as illustrated, four drains 225 are formed in the flange body 221, and each drain 225 is disposed to be spaced 90 degrees apart from each other about the central axis of the flange 220.

In this way, the control performance of the actuator 20 can be improved by disposing the plurality of drains 225 at positions symmetrical with respect to the central axis of the flange. As shown in Fig. 8, when electricity is applied to the actuator 20, a current flows through the solenoid coil to form a magnetic field as indicated by an arrow in the figure. However, when the magnetic field passes through an empty space, for example, the drain 225, the low speed density is changed so that the shape of the magnetic field is distorted. Even if there is only one drain 225 or there are a plurality of drains 225, the drain 225 is the center of the flange. The magnetic field is also not symmetrical with respect to the central axis of the flange when it is arranged symmetrically with respect to the axis, so that the force in the direction coinciding with the central axis does not act by the plunger 230 and the unnecessary force in the radial direction is also plunger ( Acting on 230 interferes with control of the plunger 230.

Furthermore, when there is only one drain 225 or is disposed symmetrically with respect to the central axis, when disassembling and reassembling the actuator 20 for repair or the like, the position of the drain 225 is different from that of the state before disassembly. Since the direction of the force acting in the radial direction acting on the plunger 230 is also different from the direction of the state before disassembly, the control of the plunger 230 is further disturbed.

However, if a plurality of drains 225 are formed as shown in the present invention, and each drain is formed at a position symmetrical with respect to the central axis of the flange, a magnetic field is formed in a uniform direction symmetrical with respect to the central axis of the flange, and the plunger 230 In addition, since only the force acting in the direction coinciding with the central axis enables precise control of the plunger 230, the flow rate control performance of the valve can be improved.

Meanwhile, referring again to FIG. 7, the flange 220 includes a sleeve coupling part 222 formed to protrude in the direction of the sleeve 30 from the surface of the flange body 221. The sleeve coupling portion 222 protrudes in a cylindrical shape and is configured such that the outer diameter of the sleeve coupling portion 222 and the inner diameter of the end 310 of the sleeve 30 are the same. Therefore, the actuator 20 may be coupled to the sleeve 30 by fitting the sleeve coupling portion 222 to the end 310 of the sleeve 30.

As will be appreciated by those skilled in the art to which the present invention pertains, various modifications and variations are possible from the description of this specification. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims.

10: housing 20: actuator
30: sleeve 40, 50: spool
110: pin 120: first spring
210: case 220: flange
230: plunger 240: piston rod
410, 420, 430, 440, 510, 520, 530, 540: land parts

Claims (7)

As a proportional pressure reducing valve,
Spool 40 having a cylindrical body 400 of a predetermined diameter having a first end and a second end, and first to fourth land portions 410, 420, 430, 440 having a diameter larger than the diameter of the body and spaced apart from each other. ;
A cylindrical sleeve having a cylindrical shape having an open first end and a second end, the cylindrical sleeve 30 being coaxially aligned with the spool 40 to surround the spool and having first to third through holes 301, 302, 303 formed therein;
An actuator (20) coupled to the second end of the sleeve and capable of forcing a second end of the spool to move the spool in the sleeve;
A housing (10) having an inner space for accommodating the sleeve (30) and having first to third flow paths (101, 102, 103) communicating with first to third through holes (301, 302, 303) of the sleeve, respectively; And
And a spring (120) interposed between the inner wall surface of the housing (10) and the first end (401) of the spool (40).
The first and second land portions 410 and 420 of the spool may open and close the first through hole 301 of the sleeve, and the fourth land portion 440 of the spool may open and close the third through hole 303 of the sleeve. ,
The third land portion 430 disposed between the second land portion 420 and the fourth land portion 440 may have at least one groove formed on one surface thereof from one end to the other end of the third land portion 430 along the length direction. 431, and
The actuator 20 includes a reciprocating plunger 230 and a piston rod 240 coupled thereto; A case 210 surrounding the plunger 230 and including a solenoid coil therein; And a flange 220 interposed between the sleeve 30 and the case 210.
The flange 220 includes at least four drains 225 that communicate between the inner space of the sleeve 30 and the inner space of the case 210 by passing through the main body 221 of the flange 220. and,
Each drain of the at least four drains 225 is formed one at a position symmetrical with respect to the central axis of the flange so that a magnetic field formed when current flows in the solenoid coil is symmetrically identical with respect to the central axis of the flange. Proportional pressure reducing valve, characterized in that formed. The method of claim 1,
Proportional pressure reducing valve, characterized in that the third land portion 430 of the spool has the same outer diameter as the inner diameter of the sleeve (30). The method of claim 1,
The first through hole 301 of the sleeve is positioned between the first land portion 410 and the second land portion 420 of the spool, and the sleeve is between the second land portion 420 and the fourth land portion 440. Of the second through hole 302, the fourth land portion 440 is located at least partially overlapping with the third through hole (303) of the sleeve. The method of claim 3, wherein the spool 40,
An annular groove 403 formed in the surface of the first end 401 of the spool;
A first hole 404 formed in the longitudinal direction of the spool and open toward the first end 401; And
And a second hole 405 formed radially in the spool between the second land part 420 and the fourth land part 440 and communicating with the first hole 404.
One end of the spring (120) is proportional pressure reducing valve, characterized in that arranged to be inserted into the annular groove (403). 5. The proportional pressure reducing valve according to claim 4, further comprising a pin (110) attached to the inner wall of the housing (10) and partially inserted into the first hole (404) of the spool (40). 6. The proportional pressure reducing valve according to claim 5, wherein an outer diameter of the pin (110) is equal to an inner diameter of the first hole (404) of the spool. The method of claim 6, further comprising at least one groove 111 formed along the circumference of the pin 110, characterized in that the fluid filled in the groove 111 during the operation of the proportional pressure reducing valve serves as a lubrication role Proportional pressure reducing valve.

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