JP2010151158A - Flow control valve of fluid pressure pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow control valve which suppresses pressure relief by thermal expansion. <P>SOLUTION: The flow control valve 100, which is interposed in a supply passage 12 that leads hydraulic oil discharged from a vane pump 101 as a fluid pressure pump to hydraulic equipment 10 to control the flow rate of the hydraulic oil supplied to the hydraulic equipment 10, includes: a valve body 27, which constitutes a body of a flow control valve 100; a sleeve 25, which is fitted in the valve body 27 to form a spool hole 31 on inside circumference; and a spool 30, which is inserted slidably in the spool hole 31 to move according to the pressure of the hydraulic oil discharged from the vane pump 101 and to return a part of the hydraulic oil discharged from the vane pump 101 to a return passage 33 communicated with the suction side of the vane pump 101. The sleeve 25 is fitted in the valve body 27 by the clearance fit and provided with a movement restraining means that seals a space between the valve body 27 and sleeve 25 and restrains the movement of a sleeve 25 in the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow rate control valve that controls the flow rate of a working fluid supplied from a fluid pressure pump to a fluid pressure device.

  2. Description of the Related Art Conventionally, fluid pressure devices that are driven using fluid pressure have been used for vehicles such as automobiles. Since the fluid pressure pump discharges the working fluid by the rotation of the engine, the flow rate of the working fluid increases in proportion to the engine speed. Therefore, in order to optimize the flow rate of the working fluid supplied to the fluid pressure device when the flow rate of the pressure oil discharged from the fluid pressure pump is excessive, the flow rate for adjusting the supply amount of the working fluid to the fluid pressure device A control valve is provided. As the flow control valve, a valve that obtains a valve action by moving a cylindrical spool in a cylindrical sleeve having suction and discharge ports is widely used.

  By the way, an aluminum body is used for the flow control valve to reduce weight, and an iron sleeve is press-fitted into the aluminum body to suppress the occurrence of erosion (erosion) due to high-pressure working fluid, making it durable. Some have improved the sexiness.

  Patent Document 1 discloses a flow control valve that uses a valve body made of aluminum and that drives and fixes a cylindrical sleeve made of another metal that is easy to process into a housing.

There is also known a press-fitting method by so-called shrink fitting, in which an iron sleeve is press-fitted into an aluminum valve body heated to a high temperature and thermally expanded.
Japanese Patent Laid-Open No. 5-87061

  However, when the sleeve is press-fitted into the valve body by shrink fitting, the sleeve is in a state of receiving a compressive load from the valve body after cooling, and the inner diameter of the sleeve at this time corresponds to the outer diameter of the spool. However, when the temperature of the flow control valve rises, the valve body holding the sleeve is thermally expanded, and the sleeve is deformed so that the inner diameter is expanded by internal stress. As a result, there is a problem that a gap is generated between the sleeve and the spool, and so-called pressure loss occurs due to leakage of hydraulic oil from the gap.

  In view of the above problems, an object of the present invention is to provide a flow control valve that can suppress pressure loss due to thermal expansion.

  The present invention is a flow rate control valve that is interposed in a supply passage that guides a working fluid discharged from a fluid pressure pump to a fluid pressure device, and controls the flow rate of the working fluid supplied to the fluid pressure device. A valve body constituting a main body of the valve, a sleeve fitted into the valve body and forming a spool hole on an inner periphery thereof, and a working fluid which is slidably inserted into the spool hole and discharged from the fluid pressure pump. A spool that moves according to pressure and returns a part of the working fluid discharged from the fluid pressure pump to a return passage that communicates with a suction side of the fluid pressure pump, and the sleeve includes the valve body. It is fitted with a clearance fit, seals between the valve body and the sleeve, and has a movement restricting means for restricting the movement of the sleeve in the axial direction.

  According to the present invention, since the sleeve is fitted into the valve body with a clearance fit, no internal stress is generated in the sleeve as in the case of press fitting during assembly. Therefore, the deformation amount of the sleeve due to thermal expansion is reduced, and leakage of the working fluid from between the spool and the sleeve can be suppressed.

  Here, when the sleeve is fitted into the valve body with a clearance fit, a gap exists between the valve body and the sleeve. However, since the movement restricting means restricts the movement of the sleeve in the axial direction and seals the working fluid between the valve body and the sleeve, the leakage of the working fluid can be prevented.

  Therefore, it is possible to obtain a flow control valve that can suppress pressure loss due to thermal expansion.

(First embodiment)
Hereinafter, the flow control valve 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of the side surface of the flow control valve 100. In this embodiment, hydraulic pressure is used as the fluid pressure.

  The flow rate control valve 100 controls the flow rate of the working fluid supplied from the fluid pressure pump, which is a hydraulic pressure supply source, to the hydraulic device 10 to have a predetermined characteristic. In the present embodiment, a case where the fluid pressure pump is a vane pump 101 driven by an engine of a vehicle will be described. The hydraulic device 10 is, for example, a power steering device or a transmission mounted on a vehicle. The hydraulic device 10 corresponds to a fluid pressure device.

  Although not shown, the vane pump 101 is configured such that engine power is transmitted to an end portion of a drive shaft, and a rotor connected to the drive shaft rotates. The vane pump 101 includes a plurality of vanes provided so as to be capable of reciprocating in the radial direction with respect to the rotor, and a cam ring that accommodates the rotor and in which the tip of the vane slides on the inner cam surface as the rotor rotates. Prepare. The cam ring is an annular member whose inner peripheral cam surface has an elliptical shape, and a plurality of pump chambers partitioned by adjacent vanes are defined in the cam ring. The cam ring has a suction region that expands the volume of the pump chamber and a discharge region that contracts the volume of the pump chamber.

  In the suction region, the vane pump 101 sucks hydraulic oil by utilizing the fact that the internal pressure is lowered by gradually expanding the volume of the oil chamber. Further, in the discharge region, hydraulic oil is discharged by utilizing the fact that the internal pressure rises as the volume of the oil chamber gradually contracts.

  The flow rate control valve 100 is interposed in a supply passage 12 that guides the hydraulic oil discharged from the vane pump 101 to the hydraulic device 10, and supplies the hydraulic oil according to the differential pressure across the variable throttle 20. A spool valve 21 for returning the hydraulic oil in the passage 12 to the pump suction side and a relief valve 22 provided on the downstream side of the variable throttle 20 are provided.

  The variable throttle 20, the spool valve 21, and the relief valve 22 are housed inside the valve body 27, and a cap 28 is screwed into the opening of the valve body 27.

  The valve body 27 constitutes the main body of the flow control valve 100 and is formed of a light material such as aluminum for weight reduction. In the present embodiment, the valve body 27 is made of aluminum. The valve body 27 is formed with a pump port 32 communicating with the vane pump 101 and into which the hydraulic oil discharged from the vane pump 101 flows in the circumferential direction. All or a part of the hydraulic oil flowing in from the pump port 32 is passed through the valve body 27. A through hole 37 penetrating in the axial direction from the supply port 29 that supplies the hydraulic device 10 is formed. A sleeve 25 constituting a spool hole 31 is fitted into the valve body 27.

  The sleeve 25 is a cylindrical member that is inserted from an opening formed in the valve body 27. The sleeve 25 is fitted into the valve body 27 with a clearance fit. The sleeve 25 is formed of a material having excellent erosion resistance such as iron so that erosion does not occur even when high-pressure hydraulic oil collides with the spool hole 31. In the present embodiment, the sleeve 25 is made of iron. That is, the valve body 27 is made of a material having a higher thermal expansion coefficient than the sleeve 25.

  As a method of press-fitting the iron sleeve 25 into the aluminum valve body 27, a method of press-fitting by shrink fitting is widely used. This is because it is possible to easily press-fit the sleeve 25 into the valve body 27 made of aluminum which has been thermally expanded by utilizing the fact that the thermal expansion coefficient of aluminum is larger than that of iron.

  However, when the aluminum valve body 27 that has been greatly thermally expanded contracts after cooling, the sleeve 25 receives a compressive load from the valve body 27. As a result, when the sleeve 25 is press-fitted into the valve body 27 by shrink fitting, the sleeve 25 is compressed by the valve body 27 when cooled after the press-fitting, so that the inner diameter of the sleeve 25 is reduced after cooling. It is necessary to process the return hole 36 that leads to the return port 33. This is because, even if the return hole 36 is formed in the sleeve 25 in advance by press-fitting by shrink fitting, it is difficult to align the position of the return hole 36 and the return port 33 of the valve body 27. Depending on the need.

  On the other hand, by inserting the sleeve 25 into the valve body 27 with a clearance fit, processing for finishing the inner periphery is not necessary. This is because the sleeve 25 does not receive a compressive load from the valve body 27 and the inner diameter of the sleeve 25 after insertion is the same as that before insertion. Therefore, since the press-fitting process is eliminated and the inner peripheral finishing process is eliminated, the number of steps required for manufacturing the flow control valve 100 can be reduced and the cost can be reduced.

  In the insertion by clearance fitting, first, a pin (not shown) is inserted into the return hole 36 formed in the sleeve 25 from the return port 33 of the valve body 27 and positioned. Then, the position of the return hole 36 can be adjusted to the position of the return port 33 by press-fitting the stopper ring 60 while being positioned.

  Further, when the oil temperature of the hydraulic oil rises during operation, the temperature of the flow control valve 100 also rises. When the sleeve 25 is press-fit by shrink fitting, the valve body 27 made of aluminum has a larger coefficient of thermal expansion than the sleeve 25 made of iron, so that the valve body 27 expands more thermally than the sleeve 25. Therefore, the force with which the valve body 27 compresses the sleeve 25 is weakened, and the sleeve 25 is greatly expanded in diameter by internal stress. Accordingly, there is a problem that hydraulic oil leaks from between the spool 30 and the sleeve 25, that is, so-called pressure loss occurs.

  On the other hand, when the sleeve 25 is fitted with a clearance fit, the diameter of the sleeve 25 when the temperature rises is smaller than when the sleeve 25 is press-fit with a shrink fit. This is because the sleeve 25 does not receive a compressive load from the valve body 27 and no internal stress is generated in the sleeve 25. Therefore, even if the temperature of the hydraulic oil rises during operation, it is possible to suppress pressure loss due to the hydraulic oil leaking from between the spool 30 and the sleeve 25 due to thermal expansion.

  The hollow portion of the sleeve 25 is a spool hole 31 that allows the pump port 32 and the return port 33 to communicate with each other. The spool 30 is slidably inserted into the spool hole 31.

  A return hole 36 communicating with a return port 33 formed in the valve body 27 is formed in the sleeve 25. The return port 33 communicates with a return passage 35 that returns excess hydraulic oil discharged from the vane pump 101 to the tank 34. That is, the return hole 36 and the return passage 35 pass through the valve body 27 from the spool hole 31 and open to the outside.

  The notch 25 b is formed in an annular shape on the inner periphery of the end portion of the sleeve 25. An annular peripheral wall 25d is formed at the end of the sleeve 25 where the notch 25b is formed. The outer diameter of the peripheral wall 25d is the same as that of the sleeve 25, and the inner diameter is smaller than the inner diameter of the sleeve 25 by the notch 25b. A stopper ring 60 as a pressing member is press-fitted from the opening of the sleeve 25 into the inner periphery of the peripheral wall 25d. This stopper ring 60 corresponds to the movement restricting means. In order to secure an area where the stopper ring 60 is press-fitted, the notch 25b is formed such that the axial length is larger than the radial thickness.

  The tip end portion 60 a of the stopper ring 60 presses the notch end portion 25 c of the notch 25 b in the axial direction of the sleeve 25. As a result, the sleeve 25 is pressed in the axial direction with the other end face in contact with the valve body 27, and the O-ring 26 a disposed between the sleeve 25 and the valve body 27 is compressed. At this time, the return port 33 and the return hole 36 are fixed so as to coincide with each other, and the stopper ring 60 is press-fitted.

  The stopper ring 60 presses the circumferential wall 25d toward the valve body 27 in the circumferential direction from the inner periphery to the outer periphery of the notch 25b. Thereby, the peripheral wall 25d is pressed against the valve body 27, and the movement of the sleeve 25 in the axial direction is restricted.

  Further, since the sleeve 25 is fitted into the valve body 27 by a clearance fit, there is a slight gap between them over the entire circumference. The hydraulic oil flows into this slight gap, but the stopper ring 60 is press-fitted, the peripheral wall 25d is pressed against the valve body 27, and the gap is closed, whereby the hydraulic oil is sealed.

  The stopper ring 60 can block the gap between the peripheral wall 25d and the valve body 27 and restrict the movement of the sleeve 25 in the axial direction even when the temperature of the hydraulic oil rises during operation and the valve body 27 is thermally expanded. It is formed with such a dimension. Thereby, the function of the stopper ring 60 is not impaired by the temperature rise during operation.

  The spool 30 slides in the spool hole 31 in the sleeve 25, but the stopper ring 60 is press-fitted into a position that does not overlap with the axial position where the spool 30 slides. Therefore, the sliding of the spool 30 is not affected. Further, the inner diameter of the stopper ring 60 is formed smaller than the inner diameter of the sleeve 25. This is to prevent interference when the spool 30 is inserted.

  From the opening of the stopper ring 60, a cap 28 having a substantially cylindrical shape and one end closed is screwed. A return spring 40 of the spool 30 is housed inside the cap 28.

  The return spring 40 abuts with the inside of the closed end of the cap 28 as the seat surface. The return spring 40 biases the spool 30 from the cap 28 in the axial direction.

  An annular notch 25 a is formed on the outer periphery of the other end of the sleeve 25. In the notch 25a, an O-ring 26 serving as a seal member is disposed by being compressed between the valve body 27 and the sleeve 25, and by closing between the outer periphery of the sleeve 25 and the inner periphery of the valve body 27, The flow of hydraulic oil between the return port 33 and the pump port 32 is blocked.

  As described above, there is a clearance due to clearance fitting between the sleeve 25 and the valve body 27. However, by pressing the stopper ring 60 into the inner periphery of the peripheral wall 25d, the peripheral wall 25d at the end of the sleeve 25 is pressed in the peripheral direction, so that the sleeve 25 is fixed and movement in the axial direction is restricted. Further, since the peripheral wall 25d is pressed against the valve body 27, the gap due to the clearance fit is closed. Thereby, the space between the sleeve 25 and the valve body 27 is sealed. That is, the stopper ring 60 has two functions of restricting movement of the sleeve 25 in the axial direction by pressing the peripheral wall 25d of the sleeve 25 in the circumferential direction and sealing between the sleeve 25 and the valve body 27.

  The spool 30 is a substantially cylindrical member that slides in the axial direction through the spool hole 31. The spool 30 and the spool hole 31 constitute a spool valve 21. The spool 30 can block communication between the pump port 32 and the return port 33 by sliding. Further, the flow rate of the working fluid that returns from the pump port 32 to the return port 33 by sliding of the spool 30 can be adjusted. That is, the spool 30 can adjust the opening area between the pump port 32 and the return port 33.

  An upstream chamber 42 that communicates with the pump port 32 and into which hydraulic oil discharged from the vane pump 101 is guided is defined at the front end side of the spool 30. Further, a spring chamber 39 for accommodating the return spring 40 is defined on the back side of the spool 30.

  A tapered rod 41 is formed at the tip of the spool 30 and is inserted into the through hole 37 of the valve body 27 and is increased in diameter toward the tip. As the spool 30 moves, the taper rod 41 moves relative to the through hole 37, and the opening area of the through hole 37 changes. The variable diaphragm 20 is configured by the taper rod 41 and the through-hole 37 whose opening area changes as the taper rod 41 moves.

  The variable throttle 20 is provided facing the upstream chamber 42 and imparts resistance to the hydraulic oil flowing through the supply passage 12. A downstream chamber 44 defined on the downstream side of the variable throttle 20 communicates with the spring chamber 39 through the through hole 43. Thus, the pressure on the upstream side of the variable throttle 20 acts on one end of the spool 30 and the pressure on the downstream side of the variable throttle 20 acts on the other end. Therefore, the spool 30 moves in accordance with the change in the differential pressure across the variable throttle 20, and balances the load based on the differential pressure across the variable throttle 20 and the urging force of the return spring 40 at a balanced position.

  The upstream chamber 42 and the downstream chamber 44 are partitioned by the separation wall 24 of the valve body 27. An opening 24 a through which the taper rod 41 is inserted is formed in the approximate center of the separation wall 24. The opening 24 a constitutes a part of the through hole 37. One surface of the separation wall 24 constitutes a seat 24b on which the spool 30 comes into contact.

  When the flow rate of hydraulic oil discharged from the vane pump 101 is large and the differential pressure across the variable throttle 20 increases, the spool 30 moves in a direction to compress the return spring 40, and the land portion 30 a of the spool 30 opens the return port 33. To do.

  When the spool 30 moves and the land portion 30 a opens the return port 33, the pump port 32 communicates with the return port 33 through the upstream chamber 42, and a part of the hydraulic oil discharged from the vane pump 101 returns to the return passage 35. To do. The flow rate of the hydraulic oil returning to the return passage 35 increases as the differential pressure across the variable throttle 20 increases, because the amount of movement of the spool 30 increases and the opening area of the return port 33 increases. That is, the engine speed increases and the flow rate of the hydraulic oil discharged from the vane pump 101 increases as the engine speed increases.

  A return hole 36 perpendicular to the spool hole 31 is formed through the sleeve 25 on the wall surface of the spool hole 31 facing the return port 33. The return hole 36 is provided in order to balance the pressure in the direction orthogonal to the axis of the spool 30 and to increase the area through which the hydraulic oil flows to suppress the flow velocity. The return hole 36 can communicate with the pump port 32 by sliding of the spool 30. One of the plurality of return holes 36 is formed on the moving shaft so as to penetrate from the return port 33 and communicates with the return port 33.

  In addition to the configuration in which two return holes 36 are provided at intervals of 180 degrees as in this embodiment, three return holes 36 are provided at intervals of 120 degrees, four at intervals of 90 degrees, six at intervals of 60 degrees, and many. It is also possible to provide a configuration. This is because the return hole 36 can be formed in the sleeve 25 in advance in the insertion by the clearance fit, unlike the press-fit by the shrink fit. If the opening area is increased by increasing the number of the return holes 36, the area of the flow path through which the hydraulic oil flows is expanded accordingly, so that the flow velocity of the hydraulic oil can be reduced and erosion can be suppressed. it can.

  At this time, in order to balance the pressure in the direction orthogonal to the axis of the spool 30, it is desirable to provide the return holes 36 at an equal pitch over the entire circumference. Since the return holes 36 can be formed in the sleeve 25 in advance, they can be provided at an equal pitch over the entire circumference.

  An annular oil chamber 50 formed in an annular shape with a substantially rectangular cross section is provided on the back side of the land portion 30 a of the spool 30, and an oil chamber is defined by the annular oil chamber 50 and the inner periphery of the spool hole 31.

  The annular oil chamber 50 communicates with the return port 33 and the return hole 36. When the spool valve 21 is opened, hydraulic oil flows into the annular oil chamber 50 from the upstream chamber 42 through the return hole 36. The hydraulic oil that has flowed into the annular oil chamber 50 flows through the annular oil chamber 50 to the return port 33.

  As described above, the spool valve 21 returns a part of the hydraulic oil flowing from the pump port 32 to the return port 33 according to the differential pressure across the variable throttle 20.

  When the pressure on the downstream side of the variable throttle 20 reaches a predetermined value, the relief valve 22 is opened by compressing the spring 45 housed in the spool 30. When the relief valve 22 is opened, the hydraulic oil on the downstream side of the variable throttle 20 flows in the order of the downstream chamber 44, the through hole 43, the spring chamber 39, the relief valve 22, and the return port 33, and enters the return passage 35. Escaped.

  Hereinafter, operations of the variable throttle 20 and the spool valve 21 will be described.

  In the low speed range of the pump speed, the differential pressure across the variable throttle 20 is small, so the spool valve 21 is closed, and hydraulic oil proportional to the pump speed is supplied to the hydraulic device 10.

  When the pump speed reaches the middle speed range, the spool valve 21 is opened by the differential pressure across the variable throttle 20, and the pump port 32 and the return port 33 communicate with each other. It returns to the return passage 35 in accordance with the increase in the pump speed. For this reason, the flow rate of the hydraulic oil supplied to the hydraulic device 10 through the variable throttle 20 is kept substantially constant.

  When the pump speed reaches the high speed range, the differential pressure across the variable throttle 20 increases, so the spool 30 moves while compressing the return spring 40. Thereby, the opening area of the opening part of the through-hole 37 is gradually reduced by the movement of the taper rod 41, and the flow rate of the hydraulic oil supplied to the hydraulic device 10 is gradually reduced.

  Further, when the vane pump 101 is stopped when the pump rotation speed becomes zero, the spool 30 is seated on the seat 24 b of the separation wall 24 by the urging force of the return spring 40. As a result, the variable throttle 20 is fully closed, the return port 33 is closed by the land portion 30a of the spool 30, and the spool valve 21 is also fully closed.

  As described above, in the present embodiment, the spool 30 is moved according to the differential pressure across the variable throttle 20, and the spool valve 21 is opened and closed. However, the spool 30 may be moved by the balance between the pressure of the working fluid flowing from the pump port 32 and the urging force of the return spring 40 instead of depending on the differential pressure across the variable throttle 20.

  According to the above embodiment, the following effects are produced.

  Since the sleeve 25 is fitted into the valve body 27 with a clearance fit, no internal stress is generated in the sleeve 25 as in the case of press fitting during assembly. Therefore, the deformation amount of the sleeve 25 due to thermal expansion is reduced, and leakage of hydraulic oil from between the spool 30 and the sleeve 25 can be suppressed.

  Here, there is a gap between the valve body 27 and the sleeve 25 when the clearance is fitted. However, since the stopper ring 60 presses the peripheral wall 25d of the sleeve 25 against the valve body 27, the movement of the sleeve 25 in the axial direction is restricted, and the hydraulic oil between the sleeve 25 and the valve body 27 is sealed to operate. Oil leakage can be prevented.

  Therefore, it is possible to obtain the flow control valve 100 that can suppress pressure loss due to thermal expansion.

  In addition, when the sleeve 25 is formed by press fitting such as shrink fitting, the sleeve 25 is deformed at the time of press fitting, so that processing for finishing the inner periphery of the sleeve 25 to the design dimension after press fitting and processing of the return hole 36 are required. . On the other hand, by inserting the sleeve 25 by clearance fitting, the sleeve 25 is not deformed at the time of insertion, and finishing processing is unnecessary. Therefore, since the press-fitting process and the inner peripheral finishing process are eliminated, the man-hours necessary for manufacturing the flow control valve 100 can be reduced, and the cost can be reduced. Further, by forming a large number of return holes 36, the flow rate of hydraulic oil can be reduced, and erosion can be suppressed.

(Second Embodiment)
Hereinafter, a flow control valve 200 of a fluid pressure pump according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view of the side surface of the flow control valve 200. In each embodiment shown below, the same reference numeral is given to the configuration that performs the same function as the above-described embodiment, and the description thereof is omitted.

  The second embodiment is different from the first embodiment in that O-rings 26a and 226b are disposed at both ends of the sleeve 225 and fixed by a stopper ring 260 press-fitted from one end.

  The sleeve 225 is a cylindrical member that is inserted from the opening of the valve body 27 by clearance fitting. On the outer periphery of both ends of the sleeve 25, annular notches 25a and 225b are formed.

  An annular peripheral wall 225d is formed at the end of the sleeve 225 where the notch 225b is formed. The inner diameter of the peripheral wall 225d is the same as that of the sleeve 225, and the outer diameter is smaller than the outer diameter of the sleeve 225 by the notch 225b.

  An O-ring 226b is disposed in the notch 225b and is compressed by the valve body 227 and the peripheral wall 225d. The O-ring 226 b seals hydraulic fluid that tends to flow between the spring chamber 39 and a slight gap between the valve body 227 and the sleeve 225 due to clearance fitting.

  A stopper ring 260 having an outer diameter equal to or larger than the outer diameter of the sleeve 225 is press-fitted into the opening of the valve body 227 in which the sleeve 225 is fitted. The stopper ring 260 contacts the end of the peripheral wall 225d. The sleeve 225 is fitted into the valve body 227 with a clearance fit, while the stopper ring 260 is press-fitted into the valve body 227 with a tight fit. Thus, the outer diameter of the stopper ring 260 is larger than the outer diameter of the sleeve 225 by the difference in the fitting dimension.

  The sleeve 225 is fixed to the valve body 227 by press-fitting the stopper ring 260. Specifically, the stopper ring 260 is fixed by being pressed into the valve body 27 while pressing the sleeve 225 toward the valve body 227 in the axial direction, and restricts the movement of the sleeve 225 in the axial direction. This stopper ring 260 corresponds to the movement restricting means.

  According to the above embodiment, since the sleeve 225 is fitted into the valve body 227 with a clearance fit, no internal stress is generated in the sleeve 225 as in the case of press fitting during assembly. Therefore, the deformation amount of the sleeve 225 due to thermal expansion becomes small, and it is possible to suppress the hydraulic oil from leaking between the spool 30 and the sleeve 225.

  Here, there is a gap between the valve body 227 and the sleeve 225 when the clearance is fitted. However, the press-fitted stopper ring 260 restricts the movement of the sleeve 225 in the axial direction, and the O-ring 226b disposed between the peripheral wall 225d of the sleeve 225 and the valve body 227 seals the hydraulic oil. Therefore, leakage of hydraulic oil can be prevented.

  Therefore, it is possible to obtain the flow control valve 200 that can suppress pressure loss due to thermal expansion.

(Third embodiment)
Hereinafter, a flow control valve 300 of a fluid pressure pump according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of the side surface of the flow control valve 300.

  The third embodiment is different from the second embodiment in that the sleeve 225 is fixed by screwing a stopper screw 360 instead of the stopper ring 260 of the second embodiment.

  A female thread 327 a on the inner peripheral surface of the valve body 327 to which the cap 28 is screwed is formed up to the end face on the back side of the sleeve 225. A disc-shaped stopper screw 360 is screwed into the opening of the valve body 327 in which the sleeve 325 is inserted. The sleeve 225 is pressed against the valve body 327 in the axial direction by the fastening force of the stopper screw 360. The stopper screw 360 is fixed by being fastened to the valve body 327, and the sleeve 225 is restricted from moving in the axial direction. This stopper screw 360 corresponds to the movement restricting means.

  According to the above embodiment, since the sleeve 225 is fitted into the valve body 327 with a clearance fit, no internal stress is generated in the sleeve 225 as in the case of press fitting during assembly. Therefore, the deformation amount of the sleeve 225 due to thermal expansion becomes small, and it is possible to suppress the hydraulic oil from leaking between the spool 30 and the sleeve 325.

  Here, there is a gap between the valve body 327 and the sleeve 225 when fitted with a clearance fit. However, the screwed stopper screw 360 restricts the movement of the sleeve 225 in the axial direction, and an O-ring 226b disposed between the peripheral wall 225d of the sleeve 225 and the valve body 327 seals the hydraulic oil. Therefore, leakage of hydraulic oil can be prevented.

  Therefore, it is possible to obtain the flow control valve 300 that can suppress pressure loss due to thermal expansion. Here, by controlling the dimensional accuracy such as the axial length of the sleeve 225, the axial depth of the valve body 327, and the axial length of the cap 28, the stopper screw 360 and the cap 28 It is also possible to have an integrated structure. At this time, the movement restricting means is configured with the cap 28 itself screwed into a predetermined position of the valve body 327.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The flow control valve of the fluid pressure pump according to the present invention can be used for hydraulic equipment such as a power steering device for a vehicle and a transmission.

It is the figure which showed the side surface of the flow control valve which concerns on the 1st Embodiment of this invention with the cross section. It is the figure which showed the side surface of the flow control valve concerning the 2nd Embodiment of this invention in the cross section. It is the figure which showed the side surface of the flow control valve concerning the 3rd Embodiment of this invention in the cross section.

Explanation of symbols

100 Flow control valve 101 Vane pump 12 Supply passage 20 Variable throttle 21 Spool valve 24 Separating wall 25 Sleeve 25a Notch 27 Valve body 28 Cap 29 Supply port 30 Spool 31 Spool hole 32 Pump port 33 Return port 35 Return passage 36 Return hole 37 Through Hole 40 Return spring 41 Taper rod 42 Upstream chamber 44 Downstream chamber 45 Spring 50 Annular oil chamber 60 Stopper ring

Claims (8)

A flow rate control valve that is interposed in a supply passage that guides the working fluid discharged from the fluid pressure pump to the fluid pressure device, and controls the flow rate of the working fluid supplied to the fluid pressure device;
A valve body constituting the body of the fluid control valve;
A sleeve fitted into the valve body and forming a spool hole on the inner periphery;
A part of the working fluid discharged from the fluid pressure pump is slidably inserted into the spool hole and moved according to the pressure of the working fluid discharged from the fluid pressure pump. A spool that returns to a return passage that communicates with
The sleeve is fitted into the valve body with a clearance fit,
A flow control valve comprising a movement restricting means for sealing between the valve body and the sleeve and restricting movement of the sleeve in the axial direction.   2. The flow rate control according to claim 1, wherein the movement restricting means is a pressing member that is press-fitted into an inner periphery of one end of the sleeve and presses the end of the sleeve against the inner periphery of the valve body. valve.   The flow control valve according to claim 1, wherein the movement restricting means includes a stopper ring that is press-fitted into the inner periphery of the valve body and restricts the movement of the sleeve in the axial direction.   The flow control valve according to claim 1, wherein the movement restricting unit includes a stopper screw that is screwed into the inner periphery of the valve body and restricts the movement of the sleeve in the axial direction.   5. The seal member disposed so as to be compressed between the inner periphery of the valve body is attached to the outer periphery of the other end of the sleeve. Flow control valve.   The flow control valve according to any one of claims 1 to 5, wherein the movement restricting means is provided at a position that does not overlap with an axial position where the spool slides.   7. The apparatus according to claim 1, further comprising a plurality of return holes formed over the entire circumference of the sleeve that can communicate the supply passage and the return passage by movement of the spool. The flow control valve described in 1.   The flow control valve according to claim 7, wherein the plurality of return holes are formed at an equal pitch.

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