JP2010101336A - Spool valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of an impact or the like by increasing a damping effect on the axial displacement of a spool. <P>SOLUTION: This spool valve includes a variable restriction mechanism 15 serving as a resistance generating means to provide the damping effect on the axial displacement of the spool 7. The variable restriction mechanism 15 comprises a radial oil path 16 drilled in the spool 7 between the piston sliding hole 7A of the spool 7 and a spring chamber 13, and a piston 17 which is fixed to a cover 6 side and changes the flow path area of the oil path 16 according to the axial displacement of the spool 7. The plunger section 17B of the piston 17 restricts the opening area (flow path area) of the oil path 16 smaller on the end surface 17C side of the plunger section 17B when the spool 7 is positioned at one axial end than when the spool 7 is positioned midway in the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spool valve that is used in a construction machine such as a hydraulic excavator, for example, and that provides a shock absorbing damping action to a spool that is displaced in the axial direction according to a pressure change in a hydraulic circuit.

  In general, a hydraulic circuit used for construction machines such as a hydraulic excavator is provided with, for example, a spool valve known as a pressure control valve, a flow rate control valve, a direction control valve, or the like. A spool valve according to this type of prior art has a configuration in which a spool is inserted into a spool hole formed in a valve housing and an oil chamber as a pressure chamber is provided on the end side of the spool. (For example, refer to Patent Document 1).

  In this case, according to the prior art, a plurality of throttle grooves extending in the axial direction are formed at different positions in the axial direction on the outer periphery of the end portion of the spool, and between the plurality of throttle grooves along the outer periphery of the spool. In this way, they communicate with each other via an annular groove extending in the circumferential direction. At this time, the plurality of throttle grooves are provided in series between the oil chamber and the outflow port, and exhibit a damping effect on the movement of the spool by generating a throttle resistance for the flowing oil liquid. It is.

JP 2001-153237 A

  By the way, the above-described spool valve according to the prior art can exert a damping effect by applying a squeezing action to the oil liquid by a plurality of squeezing grooves provided on the outer periphery of the end of the spool. However, the damping effect at this time is kept substantially constant regardless of the axial displacement of the spool, and the damping effect does not change when the distance from the stroke end is approached. Further, the damping effect may decrease as the spool approaches the stroke end.

  For this reason, when emphasizing responsiveness during the movement of the spool, a sufficient damping effect cannot be obtained, and when the spool reaches one end (stroke end) in the axial direction, the displacement speed of the spool increases. In some cases, the spool may collide with the valve housing and cause an impact.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to increase the damping effect against the axial displacement of the spool and to suppress the occurrence of an impact or the like. Is to provide.

  In order to solve the above-described problems, the present invention provides a valve housing having a spool hole extending in the axial direction and provided with a plurality of passages spaced apart in the axial direction of the spool hole, and the inside of the spool hole of the valve housing. And a spool that is inserted and displaceable in the axial direction so as to communicate and block the plurality of passages with each other, and an oil that is provided on the valve housing and is filled with an oil liquid on one side of the spool hole in the axial direction. The present invention is applied to a spool valve having a chamber and resistance generating means for causing an oil liquid to flow in and out of the oil chamber in accordance with the axial displacement of the spool and to generate a throttling resistance in the circulating oil liquid.

  The feature of the configuration adopted by the invention of claim 1 is that when the spool is positioned at one end in the axial direction as compared to when the spool is in the midway position in the axial direction, the resistance generating means is This is because it is constituted by a variable throttle mechanism that reduces the flow area of the oil liquid.

  According to a second aspect of the present invention, the variable throttle mechanism is provided on the side of the valve housing, and an oil passage that is provided in the spool and flows into and out of the spool between the oil chamber and the oil chamber. The flow path variable member changes the flow path area of the oil path in accordance with the axial displacement of the spool.

  On the other hand, according to the invention of claim 3, the variable throttle mechanism is provided on the spool housing side with a plurality of pores that are provided in the spool and through which oil flows into and out of the spool. The flow path variable member is provided to change the flow path area by opening or closing any of the pores according to the axial displacement of the spool.

  According to a fourth aspect of the present invention, the variable throttle mechanism is provided on the spool housing side with a plurality of pores that are provided in the spool and through which oil flows into and out of the spool. All the pores are opened when the spool is in the middle of the axial direction, and a part of the pores is at least partially closed when the spool is displaced to one end in the axial direction. And the flow path variable member that changes the flow path area.

  According to the invention of claim 5, the variable throttle mechanism is provided on the spool housing side with a plurality of pores that are provided in the spool and through which oil liquid flows into and out of the spool. All the pores are opened when the spool is in the middle of the axial direction, and at least one of the pores is closed when the spool is displaced to one end in the axial direction. It is comprised with the flow-path variable member which changes the said flow-path area.

  According to a sixth aspect of the present invention, the spool is configured as a cylindrical valve body that opens on one side in the axial direction as a piston sliding hole and communicates with at least one of the passages on the other side. The variable path member is configured by a piston having one side integrally or separately provided with the valve housing and the other side inserted into the piston sliding hole.

  As described above, according to the first aspect of the present invention, when the spool is positioned at one end in the axial direction as compared with the case where the spool is positioned in the middle of the axial direction within the spool hole, the flow path area of the oil liquid A variable aperture mechanism is provided to reduce the. As a result, the variable throttling mechanism has a damping effect so that when the spool is slid and displaced from the midway position in the axial direction toward one end, the flow area of the oil liquid is reduced and the throttling resistance is gradually increased. And the displacement speed of the spool can be reduced. As a result, the collision of the spool with the end face of the valve housing can be decelerated and buffered before this, and the occurrence of an impact can be satisfactorily suppressed.

  According to a second aspect of the present invention, the variable throttle mechanism is constituted by an oil passage provided on the spool side and a flow passage variable member provided on the valve housing side. Thus, the flow path variable member can change the flow path area of the oil path in accordance with the axial displacement of the spool, and can exhibit a damping effect by generating a throttle resistance according to the flow path area. it can.

  On the other hand, according to the invention of claim 3, the flow path variable member of the variable throttle mechanism can change the flow path area by opening and closing any of the plurality of pores according to the axial displacement of the spool. Even in this case, a damping effect can be exhibited by generating a diaphragm resistance according to the flow path area. In addition, the total opening area, which is the sum of the opening areas of multiple pores, can be changed so as to gradually decrease according to the axial displacement of the spool. Depending on the number, etc., it can be appropriately changed.

  According to the invention of claim 4, the flow path variable member of the variable throttle mechanism opens all the plurality of pores when the spool is positioned in the middle of the axial direction, and the spool is positioned at the end on one side in the axial direction. In this case, since a part of each of the pores is at least partially closed, in this case as well, the flow area of the oil liquid can be changed according to the axial displacement of the spool, and a throttling resistance corresponding to the flow area is generated. As a result, the damping effect can be enhanced as the spool approaches the end on one side in the axial direction, and the characteristics of the damping effect can be changed variously.

  According to the invention of claim 5, the flow path variable member of the variable throttle mechanism opens all of the plurality of pores when the spool is in the middle position in the axial direction, and the spool is at one end in the axial direction. When at least one of the pores is closed, the flow area of the oil liquid can be changed and the characteristics of the damping effect can be changed variously.

  According to the sixth aspect of the present invention, when the spool formed of the cylindrical valve body is displaced so as to approach the end on the one axial side in the valve housing, the piston provided on the valve housing side slides the piston of the spool. Relative displacement is performed so as to enter the hole, and for example, a part of the pore can be closed by the piston, so that the damping effect can be enhanced. Therefore, since the variable throttle mechanism is configured using the piston, the variable throttle mechanism can be provided inside the spool, and the entire spool valve can be reduced in size and configured in a compact manner.

  Hereinafter, a case where a spool valve according to an embodiment of the present invention is used as a sequence valve will be described as an example, and will be described in detail with reference to the accompanying drawings.

  Here, FIG. 1 to FIG. 3 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a valve housing that constitutes a main body portion (outer shell) of the spool valve. The valve housing 1 includes a housing body 2 formed as a block body as shown in FIG. It is configured.

  Reference numeral 3 denotes a spool hole provided in the housing main body 2. The spool hole 3 is formed as a circular hole extending leftward and rightward (axial direction) in the housing main body 2, as shown in FIG. The side (one side) opens to the end surface 2A on one side of the housing body 2 so as to communicate with the inside of the cover 6 described later. Further, a hydraulic pilot portion 10 to be described later is provided on the other axial side (the other side) of the spool hole 3.

  Reference numerals 4 and 5 denote a plurality of passages (hereinafter referred to as oil passages 4 and 5) provided in the housing body 2. The oil passages 4 and 5 are arranged apart from each other in the axial direction of the spool hole 3. 3 communicates with the inside of the spool hole 3 via annular oil grooves 4A and 5A formed around the periphery of the spool hole 3. The oil passages 4 and 5 are communicated and blocked by a spool 7 described later via oil grooves 4A and 5A.

  Here, one of the oil passages 4 and 5 is formed to communicate with, for example, a discharge side of a hydraulic pump (not shown), and is configured as a so-called high-pressure side oil passage 4. The other oil passage 5 is configured as a low-pressure side oil passage 5 that is always in communication with a tank (not shown) or the like.

  Reference numeral 6 denotes a cover that constitutes the valve housing 1 together with the housing body 2, and the cover 6 is formed as a covered cylindrical body closed on one side with a lid portion 6A as shown in FIGS. Here, the cover 6 is detachably fixed to the end surface 2A of the housing body 2 using fastening means (not shown) such as bolts. And the cover 6 covers the axial direction one side part of the spool 7 mentioned later from the outer side, and the spring chamber 13 mentioned later is formed in the inner side.

  A spool 7 is slidably provided in the spool hole 3 of the valve housing 1. As shown in FIG. 1, the spool 7 has one side (one side) in the axial direction as a piston sliding hole 7A. It is formed as a cylindrical valve body whose inside is a drain passage 7B and whose other end 7C in the axial direction is closed. Further, on the outer peripheral side of the spool 7, an annular convex portion 7D for receiving a spring is provided on the opening end side of the cover 6, and a pressure setting spring 14 described later is in an elastically deformed state on the annular convex portion 7D. It is in contact.

  The spool 7 is provided with a plurality of oil holes 8 and 9 in the radial direction at positions between the piston sliding hole 7A and the other end 7C. The drain passage 7B in the spool 7 is always in communication. One of the oil holes 8 and 9 communicates with the oil passage 5 via the oil groove 5A as shown in FIG. 1, so that the drain passage 7B in the spool 7 It continues to communicate with the passage 5. Further, as shown in FIG. 3, the other oil hole 9 communicates with the high-pressure side oil passage 4 through an oil groove 4A and the like.

  Here, the spool 7 is slidably displaced in the axial direction along the spool hole 3 by a hydraulic pilot portion 10 and a pressure setting spring 14 which will be described later, and the annular convex portion 7D has an end surface 2A of the housing body 2 as shown in FIG. The spool 7 is in the valve closing position (stroke end in the valve closing direction). When the spool 7 is slidably displaced to the valve opening position (stroke end in the valve opening direction) as shown in FIG. 3, the oil hole 9 communicates with the oil passage 4 on the high pressure side via the oil groove 4A. Thus, the oil passages 4 and 5 are communicated with each other via the spool 7.

  Reference numeral 10 denotes a hydraulic pilot portion provided in the housing body 2, and the hydraulic pilot portion 10 is slidably provided on the other axial side of the spool hole 3 and is in contact with the other end portion 7 </ b> C of the spool 7. 11 and a pilot passage 12 for applying a pilot pressure to the end face of the pilot piston 11. Here, the pilot piston 11 is formed with a smaller diameter than the spool hole 3 and the spool 7, and drives the spool 7 in the axial direction according to the pilot pressure supplied from the pilot passage 12.

  Further, the pilot passage 12 is formed as a passage having a hole diameter smaller than the outer diameter of the pilot piston 11 and is formed to communicate with, for example, the oil passage 4 on the high pressure side. That is, a part of the pressure oil supplied to the high pressure side oil passage 4 is guided to the pilot passage 12 as a pilot pressure.

  13 is a spring chamber as an oil chamber formed in the cover 6 at one side in the axial direction of the spool 7, and a pressure setting spring 14 is disposed in the spring chamber 13. Filled with oil. Here, the pressure setting spring 14 is attached in a pre-compressed (preset) state between a spring seat 17A of a piston 17 to be described later and an annular convex portion 7D of the spool 7, and the spool 7 is set to a predetermined valve opening setting. The valve is biased in the valve closing direction (left direction in FIG. 1) by pressure.

  When the pilot pressure supplied into the pilot passage 12 (that is, the pressure in the oil passage 4 on the high pressure side) exceeds the valve opening set pressure, the pilot piston 11 of the hydraulic pilot section 10 spools the spool. 7 is pressed against the pressure setting spring 14 in the valve opening direction (right direction in FIGS. 1 to 3). At this time, the pressure setting spring 14 is elastically bent and deformed as shown in FIGS. Is done.

  Reference numeral 15 denotes a variable throttle mechanism as a resistance generating means for giving a damping action to the axial displacement of the spool 7. The variable throttle mechanism 15 is fixed to the cover 6 and a radial oil passage 16 formed in the spool 7 so that the piston sliding hole 7A of the spool 7 and the spring chamber 13 communicate with each other. And a piston 17 as a flow path variable member that changes the flow path area of the oil path 16 in accordance with the axial displacement of the spool 7.

  Here, the piston 17 has a spring seat 17A made of an annular plate on one side in the axial direction, and the spring seat 17A is in contact with the lid portion 6A of the cover 6 by the pressure setting spring 14. Retained. The other side of the piston 17 is a plunger portion 17B that is integrally formed so as to be coaxial with the spring seat 17A and extends in the axial direction. And this plunger part 17B is inserted in the piston sliding hole 7A of the spool 7 so that relative displacement is possible, and the opening area (flow path area) of the oil path 16 is shown in FIG. 2 and FIG. Change as follows.

  As a result, the variable throttle mechanism 15 causes the oil liquid in the spring chamber 13 to move from the oil passage 16 to the piston sliding hole 7A and the drain passage 7B in the spool 7 according to the axial displacement of the spool 7, that is, in the spring chamber 13. An oil solution is caused to flow in and out to generate a squeezing resistance corresponding to the opening area of the oil passage 16 in the oil fluid flowing through the oil passage 16. The opening area of the oil passage 16 is larger when the spool 7 is positioned at one end in the axial direction as shown in FIG. 3 than when the spool 7 is in the middle of the axial direction as shown in FIG. It can be squeezed small.

  The spool valve according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, when the pilot pressure in the pilot passage 12 that is increased or decreased corresponding to the pressure in the oil passage 4 is low, the spool 7 is urged by the pressure setting spring 14 in the valve opening direction shown in FIG. The annular convex portion 7D is pressed against the end surface 2A of the housing body 2. At this time, the oil hole 9 of the spool 7 is blocked from the high-pressure side oil passage 4, so that no pressurized oil flows from the high-pressure side oil passage 4 toward the low-pressure side oil passage 5.

  However, for example, the pressure of the pressure oil supplied from the hydraulic pump or the like to the oil passage 4 increases, and an excessively high pressure exceeding the valve opening set pressure of the pressure setting spring 14 may be generated. When such a high pilot pressure is supplied to the pilot passage 12, the pilot piston 11 is displaced toward one side in the axial direction as shown in FIG. As a result, the spool 7 is slid and displaced toward the one side in the axial direction against the pressure setting spring 14 by the pilot piston 11.

  As a result, the oil hole 9 of the spool 7 starts to communicate with the annular oil groove 4A (the high-pressure side oil passage 4) through a notch or the like as shown in FIG. For this reason, the high-pressure side oil passage 4 begins to communicate with the low-pressure side oil passage 5 via the oil hole 9, the drain passage 7 </ b> B, and the oil hole 8 of the spool 7. Flows to 5. At this time, if the pilot pressure in the pilot passage 12 drops below the valve opening set pressure of the pressure setting spring 14, the spool 7 tries to return to the valve closing position shown in FIG.

  However, even in the state shown in FIG. 2, the pilot pressure in the pilot passage 12 may not fall below the valve opening set pressure of the pressure setting spring 14. In this case, the spool 7 together with the pilot piston 11 is caused by the pilot pressure. However, as shown in FIG. 3, it further slides and displaces to one side in the axial direction against the pressure setting spring 14, and the tip of the spool 7 (end surface on the piston sliding hole 7 A side) is a spring seat of the piston 17. Attempts to collide strongly with 17A.

  Therefore, in the present embodiment, a variable throttle mechanism is provided as a resistance generating means for providing a damping action with respect to the axial displacement of the spool 7, and compared with the case where the spool 7 is in the midway position in the axial direction (see FIG. 2). When the spool 7 is positioned at one end in the axial direction as shown in FIG. 3, the flow passage area of the oil passage 16 is made smaller by the piston 17.

  In other words, the variable throttle mechanism 15 in this case is fixed to the radial oil passage 16 formed in the spool 7 between the piston sliding hole 7A of the spool 7 and the spring chamber 13, and fixed to the cover 6 side. And a piston 17 that changes the flow passage area of the oil passage 16 in accordance with the axial displacement of the spool 7. The plunger portion 17B of the piston 17 narrows the opening area (flow passage area) of the oil passage 16 to be small on the end surface 17C side as shown in FIG.

  As a result, the variable throttle mechanism 15 causes the oil liquid in the spring chamber 13 to flow from the oil passage 16 to the piston sliding hole 7A and the drain passage 7B in the spool 7 according to the axial displacement of the spool 7 (that is, the inside of the spring chamber 13). The oil solution is allowed to flow in and out to the outside, and a drawing resistance corresponding to the opening area of the oil passage 16 can be generated in the oil fluid flowing through the oil passage 16.

  As a result, the variable throttle mechanism 15 has an opening area of the oil passage 16 on the end surface 17C side of the piston 17 when the tip of the spool 7 (end surface on the piston sliding hole 7A side) approaches the spring seat 17A of the piston 17. The damping effect can be increased so that the aperture resistance is increased by gradually reducing the aperture resistance, and the displacement speed can be rapidly reduced.

  Therefore, according to the present embodiment, the tip of the spool 7 collides with the spring seat 17A of the piston 17 can be buffered by the damping effect of the variable throttle mechanism 15, and it is possible to satisfactorily generate an impact. Can be suppressed. Thereby, it is possible to prevent the tip of the spool 7, the spring seat 17A of the piston 17 or the cover 6A of the cover 6 from being damaged, and the durability and life of each component can be improved.

  Further, the spool 7 is formed as a cylindrical valve body, and the plunger portion 17B of the piston 17 is inserted into the piston sliding hole 7A provided on the inner peripheral side thereof. For this reason, the variable throttle mechanism 17 including the oil passage 16 of the spool 7 and the piston 17 can be provided so as to be housed inside the spool 7, and the entire spool valve can be reduced in size.

  Next, FIG. 4 and FIG. 5 show a second embodiment of the present invention. In the second embodiment, the same reference numerals are given to the same components as those in the first embodiment, and The explanation will be omitted.

  However, the present embodiment is characterized in that the variable throttle mechanism 21 is provided with a plurality of (for example, two) fine throttle mechanisms 21 provided in the axial direction in the piston 17 and spool 7 described in the first embodiment. This is because it is constituted by the holes 22 and 23. In this case, the pores 22 and 23 constitute an oil passage whose flow area is changed by the plunger portion 17B of the piston 17.

  Here, one pore 22 is formed at a position where the drain passage 7B of the spool 7 and the spring chamber 13 are always in communication, and the other pore 23 is formed between the piston sliding hole 7A of the spool 7 and the spring chamber 13. Is formed in the spool 7 at a position where the two are communicated. The fine holes 23 in this case are formed so that when the spool 7 slides and displaces to the stroke end in the valve opening direction as shown in FIG. 5 and the tip of the spool 7 comes into contact with the spring seat 17A of the piston 17, Is completely closed by the plunger portion 17B, and is blocked from the piston sliding hole 7A of the spool 7 and the drain passage 7B.

  Thus, also in the present embodiment configured in this way, the total opening area of the pores 22 and 23 is changed by the piston 17 of the variable throttle mechanism 21 in accordance with the axial displacement of the spool 7. It is possible to obtain substantially the same effect as that of the first embodiment.

  In particular, according to the present embodiment, the piston 17 of the variable throttle mechanism 21 is thinned at a position where the tip of the spool 7 (end surface on the piston sliding hole 7A side) is away from the spring seat 17A of the piston 17. Both the holes 22 and 23 are in an open state, and at a position before the tip of the spool 7 abuts against the spring seat 17A of the piston 17, the pore 23 is closed by the plunger portion 17B of the piston 17, and the hole 22 is opened. The configuration is maintained as it is.

  As a result, the total opening area obtained by adding the opening areas of the plurality of pores 22 and 23 can be reduced as the spool 7 approaches the position on one side in the axial direction where the spool 7 abuts against the spring seat 17A of the piston 17. By appropriately changing the number, arrangement, and the like of the pores 22 and 23, it is possible to variously change the damping force characteristics for buffering the impact by the damping effect.

  Next, FIGS. 6 and 7 show a third embodiment of the present invention. In the third embodiment, the same reference numerals are given to the same components as those in the first embodiment, and The explanation will be omitted.

  However, the feature of this embodiment is that the variable throttle mechanism 31 is provided with a plurality of (for example, two) fine apertures provided on the piston 17 and the spool 7 that are spaced apart from each other in the axial direction in the first embodiment. This is because it is constituted by the holes 32 and 33. In this case, the pores 32 and 33 constitute an oil passage whose flow area is changed by the plunger portion 17B of the piston 17.

  Here, one pore 32 is formed at a position where the drain passage 7B of the spool 7 and the spring chamber 13 are always in communication, and the other pore 33 is formed between the piston sliding hole 7A of the spool 7 and the spring chamber 13. Is formed in the spool 7 at a position where the two are communicated. Then, as shown in FIG. 7, when the spool 7 slides and displaces to the stroke end in the valve opening direction and the tip of the spool 7 comes into contact with the spring seat 17A of the piston 17 as shown in FIG. Is partially blocked by the plunger portion 17B, and the opening area (flow channel area) is narrowed down.

  Thus, also in the present embodiment configured as described above, the total opening area of the pores 32 and 33 is changed by the piston 17 of the variable throttle mechanism 31 in accordance with the axial displacement of the spool 7. It is possible to obtain substantially the same effect as that of the first embodiment.

  In particular, according to the present embodiment, the piston 17 of the variable throttle mechanism 31 is thinned at a position where the tip of the spool 7 (the end surface on the piston sliding hole 7A side) is away from the spring seat 17A of the piston 17. Both the holes 32 and 33 are opened, and at the position where the tip of the spool 7 abuts against the spring seat 17A of the piston 17, the fine hole 33 is partially closed by the plunger portion 17B of the piston 17, and the fine hole 32 is opened. The structure is kept as it is.

  As a result, the total opening area obtained by adding the opening areas of the plurality of pores 32 and 33 can be reduced as the spool 7 approaches the position on one side in the axial direction where the spool 7 abuts against the spring seat 17A of the piston 17. By appropriately changing the number, arrangement, and the like of the pores 32 and 33, it is possible to variously change the damping force characteristics for buffering the impact by the damping effect.

  In the second and third embodiments, the case where the number of the fine holes 22 and 23 of the variable throttle mechanism 21 and the number of the fine holes 32 and 33 of the variable throttle mechanism 31 are two is described as an example. did. However, the present invention is not limited to this, and for example, the number of pores can be increased to 3 or more. Then, by increasing the number of pores and adjusting the arrangement of the pores, the degree of freedom in adjusting the damping force characteristics can be increased so that the damping effect can be further improved.

  In the first to third embodiments, the pressure setting spring 14 is provided in the spring chamber 13 in order to always urge the spool 7 toward the valve closing position (neutral position) and determine the valve opening setting pressure. The case where the structure is provided is described as an example. However, the present invention is not limited to this. For example, the present invention may be applied to a spool valve that does not use the pressure setting spring 14 or the like.

  If a means such as a spring for pressing the spring seat 17A of the piston 17 is not used on the lid 6A side of the cover 6, the axially one side of the flow path variable member (for example, the piston 17) is screwed. What is necessary is just to set it as the structure fixed to a valve housing (cover part 6A of the cover 6), or integrally forming using means, such as adhesion | attachment and welding. Further, the flow path variable member is not limited to the piston 17 or the like. For example, a cylindrical member is provided integrally or separately on the cover 6 side, and one side of the spool can slide on the inner peripheral side of the cylindrical member. The oil passage 16 (the pores 22 and 33) may be opened and closed by a cylindrical member.

It is a longitudinal cross-sectional view which shows the spool valve by the 1st Embodiment of this invention in the state which the spool stopped in the valve closing position. FIG. 2 is a longitudinal sectional view showing a state in which the spool in FIG. 1 is displaced to an intermediate position in the axial direction toward the valve opening position. It is a longitudinal cross-sectional view which shows the state which carried out sliding displacement to the stroke end used as a valve open position. It is a longitudinal cross-sectional view which shows the spool valve by the 2nd Embodiment of this invention. FIG. 5 is a longitudinal sectional view showing a state in which the spool in FIG. 4 is slidably displaced to a stroke end at a valve opening position. It is a longitudinal cross-sectional view which shows the spool valve by the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view shown in the state which the spool in FIG. 6 slide-displaced to the stroke end of a valve opening position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve housing 2 Housing body 3 Spool hole 4 High pressure side oil passage 5 Low pressure side oil passage 6 Cover 7 Spool 7A Piston sliding hole 7B Drain passage 8,9 Oil hole 10 Hydraulic pilot part 13 Spring chamber (oil chamber)
14 Pressure setting spring 15, 21, 31 Variable throttle mechanism (resistance generating means)
16 Oil passage 17 Piston (Flow path variable member)
22, 23, 32, 33 pores

Claims (6)

A valve housing having a spool hole extending in the axial direction and provided with a plurality of passages spaced apart in the axial direction of the spool hole, and inserted into the spool hole of the valve housing so as to be axially displaceable. A spool that communicates with and shuts off the passage; an oil chamber that is located on one side of the spool hole in the axial direction and that is provided in the valve housing and is filled with oil; and the oil chamber according to the axial displacement of the spool In the spool valve provided with resistance generating means for causing the oil liquid to flow in and out, and to generate a squeezing resistance in the circulating oil liquid,
The resistance generating means is constituted by a variable throttle mechanism that reduces the flow area of the oil liquid when the spool is positioned at one end in the axial direction as compared to when the spool is in the middle of the axial direction. A spool valve characterized by that.   The variable throttle mechanism includes an oil passage that is provided in the spool and in which oil liquid flows into and out of the oil chamber, and an oil passage that is provided on the valve housing side according to the axial displacement of the spool. The spool valve according to claim 1, wherein the spool valve is configured by a flow path variable member that changes a flow path area of the first flow path.   The variable throttle mechanism is provided on the spool housing according to an axial displacement of a plurality of pores provided on the valve housing side and a plurality of pores through which oil liquid flows into and out of the spool. The spool valve according to claim 1, wherein the spool valve is configured by a flow path variable member that opens and closes each of the pores to change the flow path area.   The variable throttle mechanism includes a plurality of pores through which oil is introduced into and out of the spool between the variable throttle mechanism and the oil chamber, and the spool is provided on the valve housing side and is in the middle of the axial direction. A fluid passage variable member that opens all the pores when the fluid is in a position and changes the flow passage area by at least partially closing a portion of each pore when the spool is displaced to one side in the axial direction. The spool valve according to claim 1, comprising:   The variable throttle mechanism includes a plurality of pores through which oil is introduced into and out of the spool between the variable throttle mechanism and the oil chamber, and the spool is provided on the valve housing side and is in the middle of the axial direction. A fluid passage variable member that opens all of the pores when closed and closes at least one of the pores to change the flow passage area when the spool is displaced to one side in the axial direction. The spool valve according to claim 1, wherein the spool valve is configured.   The spool is configured as a cylindrical valve body that opens as a piston sliding hole on one side in the axial direction and communicates with at least one of the passages on the other side, and the flow path variable member has the valve housing on one side 6. The spool valve according to claim 2, 3, 4 or 5, wherein the spool valve is formed of a piston which is provided integrally or separately with the other side and is inserted into the piston sliding hole.

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