Valve device

Abstract

A solenoid valve (1) is provided with a sleeve (22), a spool (23), and a filter (31). The filter (31) has a first filter (32) and a second filter (33). The first filter (32) is wound around the outer peripheral surface of the sleeve (22) in a state in which a part of the outer peripheral surface in the circumferential direction is exposed. The second filter (33) is wound around the outer peripheral side of the first filter (32), and both ends (33A, 33B) in the circumferential direction are fixed to the outer peripheral surface of the sleeve (22) and exposed from the first filter (32).

Description

Technical Field

[0001] The present disclosure relates to a valve device incorporated in a hydraulic circuit of a construction machine such as a hydraulic excavator or a wheel loader. Background Art

[0002] In recent years, the demand for automatic driving has been increasing in construction machinery represented by hydraulic excavators, and the electronic control of construction machinery has been continuously promoted. As an example of electronic control of construction machinery, there is a known method of operating a control valve (Control Valve) for controlling an actuator (hydraulic cylinder, hydraulic motor) of a construction machinery using a hydraulic pressure controlled by a solenoid valve (solenoid valve). On the other hand, Patent Document 1 discloses a solenoid valve (solenoid valve) for advancing or retarding the valve timing of an engine. The port of the sleeve (valve sleeve) of the solenoid valve of Patent Document 1 is covered with a filter.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-22816 Summary of the invention

[0006] The solenoid valve described in Patent Document 1 has a filter wound around the outer circumference of the sleeve at a position corresponding to the port. In contrast, in order to ensure the strength of the filter or to improve the filtering performance of the filter, it is considered to wind multiple filters around the outer circumference of the sleeve. However, in a structure where multiple filters are wound in an overlapping manner, it is difficult to stably fix each filter.

[0007] One of the objects of the present invention is to provide a valve device capable of stably mounting a plurality of filters on a sleeve.

[0008] Preferably, the valve device of the present invention comprises: a sleeve provided with a port and a valve core hole connected to the port; a valve core inserted into the valve core hole of the sleeve and moving axially in the valve core hole; and a filter wound circumferentially on the outer peripheral side of the sleeve and at a position corresponding to the port. In the valve device, the filter comprises: a first filter wound on the outer peripheral surface of the sleeve with a portion of the outer peripheral surface exposed in the circumferential direction, and both ends in the circumferential direction are fixed to the outer peripheral surface of the sleeve; and a second filter wound on the outer peripheral side of the first filter, and both ends in the circumferential direction are fixed to the portion of the outer peripheral surface of the sleeve exposed from the first filter between the two ends in the circumferential direction of the first filter.

[0009] According to the present invention, a plurality of filters can be stably mounted on the sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view showing a valve device (solenoid valve) according to the embodiment.

[0011] Figure 2 It is a cross-sectional view showing the valve device in a state of being assembled to the control valve.

[0012] Figure 3 It is a partial cross-sectional view showing the valve portion of the valve device.

[0013] Figure 4 yes Figure 3 An enlarged cross-sectional view of part (IV).

[0014] Figure 5 It is a front view showing the sleeve to which the first filter is fixed.

[0015] Figure 6 It is a front view showing the sleeve to which the first filter and the second filter are fixed.

[0016] Figure 7 is from Figure 5 A cross-sectional view of the first filter, sleeve, valve column, etc. observed in the direction of arrow VII-VII.

[0017] Figure 8 is from Figure 6 A cross-sectional view of the first filter, the second filter, the sleeve, the valve column, etc. observed in the direction of arrows VIII-VIII.

[0018] Fig. 9 It is an explanatory diagram showing the first filter and the second filter in an expanded form.

[0019] Fig.10 1 is a diagram showing a first filter, a second filter, a sleeve, a valve column, etc. of a first modified example. Figure 8 Section view at the same location.

[0020] Fig.11 is a diagram showing a filter according to a second modification example. Figure 4 Section view at the same location.

[0021] Fig.12 It is a half-sectional view showing a valve device (safety valve) according to a third modified example. DETAILED DESCRIPTION

[0022] Hereinafter, the valve device according to the embodiment will be described in detail with reference to the drawings, taking as an example a case where the valve device is applied to a solenoid valve incorporated in a hydraulic circuit of a construction machine.

[0023] Figures 1 to 9 An embodiment is shown. Figure 1 and Figure 2In the embodiment, the electromagnetic valve 1 as a valve device is configured as an electromagnetic valve (solenoid valve). The electromagnetic valve 1 uses the plunger 9 of the solenoid part 2 to drive the valve column 23 of the valve part 21 in the axial direction to open and close the flow path. The electromagnetic valve 1 is assembled in the control port part of the device that controls the flow and pressure of the control fluid (such as working oil). For example, Figure 2 As shown, the solenoid valve 1 is assembled in a control valve 41 of a hydraulic excavator (not shown) which is a typical example of a construction machine. In this case, the solenoid valve 1 is attached to a housing 42 of the control valve 41, for example.

[0024] The control valve 41 of the hydraulic excavator is a control valve group (control valve device) composed of multiple directional control valves. The control valve 41 of the hydraulic excavator distributes the pressure oil ejected from the hydraulic pump (not shown) to multiple hydraulic actuators (hydraulic cylinders, hydraulic motors) such as the boom cylinder, the arm cylinder, the bucket cylinder, the travel hydraulic motor, and the rotation hydraulic motor (not shown) according to the operation of the travel operating lever, the pedal, and the working operating lever (not shown) operated by the operator. The solenoid valve 1 opens and closes the flow path based on the supply of power from the control device (not shown) that controls the solenoid valve 1. As a result, the solenoid valve 1 can control the pilot pressure oil that causes the valve column (not shown) of the control valve 41 to displace (move).

[0025] like Figures 1 to 3 As shown, the solenoid valve 1 includes a solenoid portion 2 as an actuator and a valve portion 21 driven by the solenoid portion 2. The solenoid valve 1 is configured as a pressure control valve (proportional solenoid valve, proportional solenoid valve) that switches the positions of three ports of the valve portion 21 by using the solenoid portion 2. The solenoid portion 2 and the valve portion 21 are coaxially arranged.

[0026] First, the solenoid unit 2 will be described. Figure 2 As shown, the solenoid part 2 includes a coil 3, a shell 4 as a fixing part, an anchor 5, a yoke 6, an abutment part 7 and a connecting part 8, a plunger 9 as a movable part, a working pin 10, a spring 11, and a socket 12. The coil 3 is formed by winding a conductive wire in a ring shape. The coil 3 generates a magnetic force by supplying power (energization) from the outside. The shell 4 is formed in a bottomed cylindrical shape. The shell 4 is arranged on the inner circumference side of the coil 3. The shell 4 extends along the axial direction of the coil 3, and one end side ( Figure 2 A connecting component 8 is fixed to one end of the housing 4.

[0027] The anchor 5 is formed into a cylindrical shape with both ends of the axial direction open. The anchor 5 is provided on one side of the moving direction of the plunger 9 ( Figure 2 On the right side of the anchor 5 at one end side in the axial direction ( Figure 2The sleeve 22 of the valve part 21 is installed on the right end side of the anchor 5. That is, an internal thread 5A is formed on the inner periphery of one end side of the anchor 5. The external thread 22N of the sleeve 22 is threadedly engaged with the internal thread 5A of the anchor 5. On the other hand, the other end side ( Figure 2 The left end side of the anchor 5) extends axially toward the housing 4 on the inner circumference side of the coil 3. Figure 2 The left end side of the fixing connecting part 8.

[0028] The yoke 6 is formed in a cylindrical shape with both ends of the axial direction open. The yoke 6 is arranged radially outside the housing 4 and the anchor 5. One end side of the yoke 6 in the axial direction ( Figure 2 The yoke 6 is mounted on the housing 42 of the control valve 41 (right end side). That is, an external thread 6A is formed on the outer periphery of one end side of the yoke 6. The external thread 6A of the yoke 6 is threadedly engaged with the internal thread 42E of the control port portion 42A provided in the housing 42 of the control valve 41. In addition, the yoke 6 is fitted on the inner periphery of one end side of the yoke 6. That is, the inner peripheral surface of one end side of the yoke 6 abuts against the outer peripheral surface of one end side of the anchor 5.

[0029] On the other hand, the other end side of the yoke 6 ( Figure 2 The left end side of the yoke 6 extends axially toward the socket 12 on the outer peripheral side of the coil 3. The yoke 6 is a magnetic component that forms a magnetic circuit (magnetic path) together with the shell 4 throughout the inner and outer peripheral sides of the coil 3. In this case, an abutment component 7 is arranged on the other end side of the yoke 6, which is located between the inner periphery of the yoke 6 and the outer periphery of the shell 4 and forms a magnetic circuit between the above-mentioned yoke 6 and the shell 4. The inner periphery of the abutment component 7 abuts against the outer periphery of the shell 4 throughout the entire circumference, and a circumferential portion of the outer periphery of the abutment component 7 abuts against the inner periphery of the yoke 6. As a result, magnetic flux can be exchanged between the yoke 6 and the shell 4.

[0030] The connecting member 8 is formed into a cylindrical shape with both ends opened in the axial direction. The connecting member 8 is made of a non-magnetic material. One side of the connecting member 8 in the axial direction ( Figure 2 The right side of the axial direction is fixed to the anchor 5, and the other side ( Figure 2 The plunger 9 is formed into a cylindrical shape with both ends open in the axial direction. The plunger 9 is configured to be movable along the axial direction of the coil 3. That is, the plunger 9 is arranged on the inner side of the housing 4 and is movable in the axial direction between the housing 4 and the anchor 5. The working pin 10 is fixed to the plunger 9. The working pin 10 moves integrally with the plunger 9. The working pin 10 transmits the thrust of the plunger 9 to the valve column 23 of the valve portion 21.

[0031] The spring 11 is arranged between the bottom of the housing 4 and the plunger 9. The spring 11 allows one end of the working pin 10 ( Figure 2 The right end of the valve stem 23 will not be far away from the other end ( Figure 2The working pin 10 is pressed toward the valve column 23 via the plunger 9 in a manner of moving the valve rod 23 to the left end of the valve rod 23. A cable (not shown) for supplying power to the coil 3 of the solenoid part 2 is connected to the socket 12. The coil 3 excites or demagnetizes the anchor 5 by supplying power to move the plunger 9 closer to or farther from the anchor 5. As a result, the valve column 23 of the valve part 21 is driven in the axial direction by the solenoid part 2 (plunger 9).

[0032] Next, the valve portion 21 will be described. Figure 2 and Figure 3 As shown in FIG. 2 , the valve portion 21 includes a sleeve 22 serving as a valve sleeve, a valve stem 23 serving as a valve core, and a return spring 24. Figure 2 As shown, the valve portion 21 is mounted together with the solenoid portion 2 in the housing 42 of the control valve 41. That is, the housing 42 of the control valve 41 is provided with a control port portion 42A to which the solenoid valve 1 is mounted. The control port portion 42A is provided with an internal thread 42E so as to be located on the opening side.

[0033] The valve portion 21 is inserted into the control port portion 42A. The valve portion 21 and the solenoid portion 2 are fixed to the housing 42 of the control valve 41 by threading the external thread 6A of the solenoid portion 2 with the internal thread 42E of the control port portion 42A. That is, the solenoid valve 1 is fixed to the housing 42 of the control valve 41 by threading the external thread 6A of the solenoid portion 2 with the internal thread 42E of the control port portion 42A. A sealing ring 43 (O-ring) is provided between the inner peripheral surface of the control port portion 42A and the outer peripheral surface of the valve portion 21 to seal them.

[0034] like Figure 2 and Figure 3 As shown, the sleeve 22 is formed into a bottomed cylindrical shape. That is, the sleeve 22 is provided with a sliding hole 22A as a valve core hole into which the valve column 23 can be slidably inserted. The sleeve 22 has one side ( Figure 2 and Figure 3 The large diameter cylinder portion 22B located on the other side in the axial direction ( Figure 2 and Figure 3 The sleeve 22 is formed into a cylindrical shape with a bottom and a step, and extends in the axial direction. Moreover, the end (one end) of the sleeve 22 opposite to the solenoid part 2 is closed by the bottom 22D.

[0035] The large diameter cylinder 22B is provided with a pump port 22E, a tank port 22F, and an actuator port 22G through which a control fluid passes. The pump port 22E, which serves as a supply port, is formed in the large diameter cylinder 22B as an oil passage extending in the radial direction of the large diameter cylinder 22B. One side of the pump port 22E opens on the outer diameter side of the large diameter cylinder 22B, and the other side opens in the sliding hole 22A. The opening on one side of the pump port 22E opens in an annular recess 22H provided on the outer peripheral surface of the large diameter cylinder 22B.

[0036] The annular recess 22H is formed on the outer peripheral surface of the large diameter cylinder 22B as a groove having a smaller outer diameter than the adjacent portion in the axial direction. The pump port 22E is connected to a hydraulic pump (not shown), such as a pilot pump of a hydraulic excavator, via a pump oil passage 42B provided in the housing 42 of the control valve 41. As will be described below, the annular recess 22H opened in the pump port 22E is provided with a filter 31 in a manner covering the opening of the pump port 22E.

[0037] The tank port 22F, which serves as a drain port, is also formed in the large diameter cylinder 22B as an oil passage extending in the radial direction of the large diameter cylinder 22B. The tank port 22F is located on the small diameter cylinder 22C side relative to the pump port 22E. One side of the tank port 22F opens on the outer diameter side of the large diameter cylinder 22B, and the other side opens in the sliding hole 22A. One side of the tank port 22F opens in the annular recess 22J provided on the outer peripheral surface of the large diameter cylinder 22B.

[0038] The annular recess 22J is formed on the outer peripheral surface of the large diameter cylinder 22B as a groove having a smaller outer diameter than an adjacent portion in the axial direction. The tank port 22F is connected to a tank (not shown), such as a hydraulic oil tank of a hydraulic excavator, via a tank oil passage 42C provided in the housing 42 of the control valve 41.

[0039] The actuator port 22G, which serves as an output port, is formed in the large diameter cylinder portion 22B as an oil passage extending in the axial direction of the large diameter cylinder portion 22B. One side of the actuator port 22G opens at the bottom portion 22D, and the other side opens at the sliding hole 22A. The other side opening of the actuator port 22G opens at the annular recessed portion 22K provided on the inner peripheral surface of the sliding hole 22A. The annular recessed portion 22K is formed in the sliding hole 22A as a full-circumferential groove having an inner diameter larger than that of an adjacent portion in the axial direction.

[0040] The annular recess 22K is located between the pump port 22E and the tank port 22F. The actuator port 22G is connected to a hydraulic actuator (not shown), for example, a hydraulic pilot chamber of a control valve (directional control valve) of a hydraulic excavator, via an actuator oil passage 42D provided in a housing 42 of the control valve 41 .

[0041] Furthermore, seal grooves 22L and 22M that are full-circumferential grooves are formed at two locations on the outer peripheral surface of the large-diameter cylinder 22B. That is, a front-end side seal groove 22L in which a front-end side seal ring 44 (O-ring) is mounted is provided on the front end side (bottom 22D side) of the large-diameter cylinder 22B. A base end side seal groove 22M in which a base end side seal ring 45 (O-ring) is mounted is provided on the base end side (small-diameter cylinder 22C side) of the large-diameter cylinder 22B and between the pump port 22E and the tank port 22F.

[0042] The distal seal ring 44 seals between the actuator port 22G (actuator oil passage 42D) and the pump port 22E (pump oil passage 42B), and the proximal seal ring 45 seals between the pump port 22E (pump oil passage 42B) and the tank port 22F (tank oil passage 42C).

[0043] The small diameter cylinder 22C of the sleeve 22 is fixed to the anchor 5 of the solenoid 2. That is, an external thread 22N is formed on the outer periphery of the small diameter cylinder 22C. The external thread 22N of the small diameter cylinder 22C is threadedly engaged with the internal thread 5A of the anchor 5 provided on the solenoid 2. Thus, the valve part 21 and the solenoid 2 can be connected as one body in a state where the valve column 23 is inserted into the sleeve 22.

[0044] The valve stem 23 is disposed in the sliding hole 22A of the sleeve 22. The valve stem 23 can move axially in the sliding hole 22A. The valve stem 23 is formed as a long rod-shaped body and extends axially on the inner peripheral side of the sleeve 22. An axial flow path 23A extending axially is formed at the axial center position of the valve stem 23.

[0045] On the other axial end side of the valve stem 23 ( Figure 2 and Figure 3 The left end side of the valve stem 23 is provided with a flange portion 23B protruding radially outward over the entire circumference. The flange portion 23B faces the end surface (opening side end surface) of the small diameter cylinder portion 22C of the sleeve 22. In addition, a return spring 24 is provided between the flange portion 23B of the valve stem 23 and the small diameter cylinder portion 22C of the sleeve 22.

[0046] The valve column 23 is pressed toward the anchor 5 side of the solenoid part 2 by the urging force of the return spring 24. For example, in a non-energized state in which power is not supplied to the coil 3 of the solenoid part 2, the other end face of the valve column 23 abuts against the end face of the anchor 5 by the urging force of the return spring 24. In this state, one end face of the operating pin 10 abuts against the other end face of the valve column 23 by the spring 11 of the solenoid part 2. That is, even when the solenoid part 2 is in a non-energized state, the abutment between the other end face of the valve column 23 and one end face of the operating pin 10 is maintained by the spring 11 of the solenoid part 2.

[0047] Welding pads 23C and 23D are provided on the outer peripheral surface of the valve stem 23 and are separated in the axial direction. In a state (non-energized state) where the other end (the other end surface) of the valve stem 23 abuts against the anchor 5 of the solenoid portion 2, the pump port 22E and the actuator port 22G are disconnected by the welding pad 23C, and the actuator port 22G and the tank port 22F are connected via the small diameter portion 23E between the welding pads 23C and 23D. In this case, the pressure oil of the actuator oil path 42D is guided to the tank oil path 42C via the actuator port 22G and the tank port 22F, and returns to the tank (working oil tank) not shown.

[0048] On the other hand, when power is supplied to the coil 3 of the solenoid portion 2, the valve stem 23 overcomes the urging force of the return spring 24 via the plunger 9 and the operating pin 10 and moves to one side in the axial direction ( Figure 2 and Figure 3 At this time, that is, when the valve stem 23 moves to one side in the axial direction, the pump port 22E and the actuator port 22G are connected via the small diameter portion 23E between the pads 23C and 23D, and the actuator port 22G and the tank port 22F are disconnected by the pad 23D. In this case, the pressure oil of the pump oil path 42B is guided to the actuator oil path 42D via the pump port 22E and the actuator port 22G, and is supplied to the hydraulic actuator (hydraulic pilot chamber of the control valve) not shown.

[0049] The valve column 23 is provided with radial flow paths 23F and 23G which penetrate in the radial direction and are separated in the axial direction. The radial flow paths 23F and 23G are connected to the axial flow path 23A. Thus, the tank (working oil tank) is connected to the inner peripheral side of the anchor 5 of the solenoid part 2 via the tank port 22F, the radial flow path 23F, the axial flow path 23A, and the radial flow path 23G. Furthermore, the inner peripheral side of the anchor 5 is connected to the inside of the plunger 9 through the inner periphery of the anchor 5 and the outer periphery of the working pin 10, and the flow path 10A provided in the working pin 10. In this way, the interior of the solenoid part 2 is configured to be connected to the tank via the valve part 21 (the interior of the valve column 23).

[0050] However, the solenoid valve described in the above-mentioned patent document 1 has a filter wound on the outer peripheral side of the sleeve and at a position corresponding to the port. In contrast, in order to ensure the strength against deformation of the filter or to improve the filtering performance of the filter, it is considered to wind multiple filters on the outer peripheral side of the sleeve. However, if the filter is only wound into two or three layers, the installation state of the filter relative to the sleeve may become unstable. In particular, when filters with different mesh sizes are fixed to the sleeve by welding or bonding, in this state, the overlap between the filters varies depending on the fixed position, and the fixed state is prone to become unstable.

[0051] In contrast, in the embodiment, the filter 31 is composed of two filters 32 and 33, namely, the first filter 32 located radially inside and the second filter 33 located radially outside. Figure 7 As shown in FIG. 1 , the first filter 32 is wound around the outer circumference of the sleeve 22 in a notched annular shape (C-shaped). Figure 5 As shown, the first filter 32 is wound around the outer peripheral surface of the sleeve 22 in a state where a portion of the outer peripheral surface of the sleeve 22 in the circumferential direction is exposed.

[0052] More specifically, the first filter 32 is wound around the outer circumferential surface (bottom surface of the annular recess 22H) of the sleeve 22, with the two circumferential ends 32A and 32B facing each other in a circumferentially separated state. Thus, the outer circumferential surface of the sleeve 22 between the one circumferential end 32A and the other circumferential end 32B of the first filter 32 is exposed from the first filter 32.

[0053] On this basis, if Figure 6 and Figure 8 As shown, the second filter 33 is wound around the outer circumference of the first filter 32 in an annular shape (O-shaped) and radially outward of the first filter 32. In addition, the second filter 33 may also be as follows Fig.10 In any case, both ends 33A and 33B of the second filter 33 in the circumferential direction are fixed to the portion of the outer circumferential surface of the sleeve 22 between the two ends 32A and 32B of the first filter 32 that is exposed from the first filter 32 (the portion not covered by the first filter 32). Thus, in the embodiment, both the first filter 32 and the second filter 33 can be stably fixed to the outer circumferential surface of the sleeve 22. This point will be described in detail below.

[0054] First, in the embodiment, the solenoid valve 1 as a valve device includes a sleeve 22, a valve rod 23 as a valve core, and a filter 31. The sleeve 22 is provided with ports 22E, 22F, 22G and a sliding hole 22A as a valve core hole communicating with the ports 22E, 22F, 22G. The valve rod 23 is inserted into the sliding hole 22A of the sleeve 22. The valve rod 23 moves axially in the sliding hole 22A. In this case, the valve rod 23 is displaced relative to the sleeve 22 by the solenoid part 2 as an actuator driven by the supply of electric power.

[0055] The filter 31 is provided on the outer peripheral side of the sleeve 22 and at a position corresponding to the pump port 22E. In this case, the filter 31 is provided in the annular recess 22H where the pump port 22E opens. Moreover, the filter 31 is wound in the annular recess 22H in the circumferential direction of the sleeve 22. In the embodiment, the filter 31 includes a first filter 32 and a second filter 33.

[0056] The first filter 32 is wound on the outer peripheral surface of the sleeve 22 (the bottom surface of the annular recess 22H) with a portion of the outer peripheral surface exposed in the circumferential direction. That is, when the first filter 32 is wound on the outer peripheral surface of the sleeve 22, both ends 32A and 32B in the circumferential direction face each other in a state of being separated in the circumferential direction. Moreover, both ends 32A and 32B in the circumferential direction of the first filter 32 are fixed to the outer peripheral surface of the sleeve 22.

[0057] Thus, the first filter 32 is fixed to the outer peripheral surface of the sleeve 22, and the portion of the outer peripheral surface of the sleeve 22 between the one end 32A and the other end 32B in the circumferential direction of the first filter 32 is exposed. That is, the one end 32A and the other end 32B in the circumferential direction of the first filter 32 do not overlap in the radial direction on the outer peripheral surface of the sleeve 22. Figure 7 As shown, the cross-sectional shape of the first filter 32 is a notched circular ring shape (C-shape).

[0058] On this basis, the second filter 33 is wound around the outer circumference of the first filter 32. In this case, Figure 6 and Figure 8 As shown, the two ends 33A, 33B of the second filter 33 in the circumferential direction are fixed to the outer circumferential surface of the sleeve 22 between the two ends 32A, 32B of the first filter 32. Thus, the two ends 33A, 33B of the second filter 33 in the circumferential direction are fixed to the outer circumferential surface of the sleeve 22 exposed from the first filter 32.

[0059] In this case, the second filter 33 is wound around the entire outer circumference of the sleeve 22 on the radially outer side of the first filter 32. That is, the second filter 33 is wound around the outer circumference of the first filter 32 in an annular shape (O-shaped). In other words, one end 33A and the other end 33B of the second filter 33 overlap in the radial direction on the outer circumferential surface of the sleeve 22. As a result, Figure 8 As shown, the cross-sectional shape of the second filter 33 is an annular shape (O-shape).

[0060] The first filter 32 and the second filter 33 are fixed to the outer circumferential surface of the sleeve 22 by welding. That is, one end 32A of the first filter 32 in the circumferential direction is fixed to the outer circumferential surface of the sleeve 22 (the bottom surface of the annular recess 22H) by spot welding 34. The other end 32B of the first filter 32 in the circumferential direction is fixed to the outer circumferential surface of the sleeve 22 (the bottom surface of the annular recess 22H) by spot welding 35 in a state separated from the one end 32A in the circumferential direction (in other words, in a state opposed to the one end 32A with a circumferential gap therebetween). The second filter 33 is fixed to the outer circumferential surface of the sleeve 22 (the bottom surface of the annular recess 22H) by spot welding 36 in a state where the two ends 33A, 33B overlap in the radial direction. The spot weldings 34, 35, 36 correspond to the fixing parts of the filters 31 (the first filter 32, the second filter 33).

[0061] Fig. 9 FIG. 2 shows a state where the first filter 32 and the second filter 33 are unfolded, that is, before being wound around the outer peripheral surface of the sleeve 22 (the bottom surface of the annular recess 22H). Fig. 9 As shown, the length L1 of the first filter 32 is shorter than the length L2 of the second filter 33. The length L1 of the first filter 32 is shorter than the circumferential length of the outer peripheral surface of the sleeve 22, more specifically, the length of the outer periphery of the annular recess 22H.

[0062] Therefore, when the first filter 32 is wound in the annular recess 22H, the two ends 32A and 32B of the first filter 32 are circumferentially opposed via a gap. In contrast, the length dimension L2 of the second filter 33 is longer than the circumferential length of the outer peripheral surface of the sleeve 22, more specifically, the length of the outer periphery of the annular recess 22H. Therefore, when the second filter 33 is wound in the annular recess 22H, the two ends 33A and 33B of the second filter 33 overlap in the radial direction.

[0063] Furthermore, the first filter 32 and the second filter 33 are composed of mesh filters. In this case, the mesh of the first filter 32 is coarser than that of the second filter 33, and the first filter 32 has a higher strength against deformation than the second filter 33. On the contrary, the mesh of the second filter 33 is finer than that of the first filter 32, and the second filter 33 has a lower strength against deformation than the first filter 32. Here, the density of the mesh of the second filter 33 (for example, filtering performance, filtering accuracy) is set according to the size of the captured particles (contaminants) in the working oil, pressure loss, etc. Compared with such a second filter 33, the mesh of the first filter 32 is coarser.

[0064] That is, the filtering performance (filtering accuracy) of the first filter 32 is lower than the filtering performance (filtering accuracy) of the second filter 33, and the pressure loss is smaller. For example, when the particle size of the captured particles (pollutants) captured by the second filter 33 is set to 1, the particle size of the captured particles (pollutants) captured by the first filter 32 is 2 to 5 (more preferably 4 to 5). And, for example, when the pressure loss of the second filter 33 is set to 1, the pressure loss of the first filter 32 is 0.2 to 0.4 (more preferably 0.25 or less).

[0065] Furthermore, the strength of the first filter 32 can be set to ensure the required strength for both the first filter 32 and the second filter 33. In this case, when the strength of the second filter 33 is set to 1, the strength of the first filter 32 is 15 to 25 (more preferably 20 or more). Furthermore, the thickness of the filter material (constituent component) of the first filter 32 can be greater than the thickness of the filter material (constituent component) of the second filter 33. In this case, when the thickness of the filter material of the second filter 33 is set to 1, the thickness of the filter material of the first filter 32 is 2 to 5 (more preferably 2.5 or more). Furthermore, the first filter 32 can also use a filter material of a different material from that of the second filter 33.

[0066] Thus, in the embodiment, the first filter 32 has a function as a reinforcement filter that reinforces the second filter 33 on the inner diameter side of the second filter 33. In contrast, the second filter 33 has a function as a filter filter that blocks the passage of foreign matter in the working oil on the radially outer side of the first filter 32 that serves as a reinforcement filter. That is, the working oil (control fluid) flows from the pump oil passage 42B side to the pump port 22E where the first filter 32 and the second filter 33 are provided.

[0067] Therefore, the pressure on the upstream side of the second filter 33 is higher than the pressure on the downstream side of the first filter 32, and the difference in the pressure (pressure difference) is used to apply a force that presses the second filter 33 toward the first filter 32. In addition, since the second filter 33 is a mesh filter with a finer component (filter material), there is a concern that the second filter 33 may be excessively deformed, have reduced filtering performance, or be damaged due to the force based on the pressure difference. In contrast, the first filter 32 has a higher strength against deformation than the second filter 33. Therefore, the first filter 32 can suppress the deformation of the second filter 33 and can suppress the damage to the second filter 33. As a result, the filtering performance of the second filter 33 can be ensured, and the installation state of the second filter 33 can be stabilized.

[0068] The solenoid valve 1 according to the embodiment has the above-described structure, and the operation of the solenoid valve 1 will be described below.

[0069] First, the solenoid valve 1 is connected to a control device (not shown) that controls the solenoid valve 1. That is, a plug (not shown) of a cable extending from the control device is connected to the socket 12 of the solenoid valve 1. When the coil 3 of the solenoid part 2 is not powered, the valve column 23 of the valve part 21 is biased toward the solenoid part 2 by the return spring 24, and the other end face of the valve column 23 abuts against one end face of the solenoid part 2 (anchor 5). As a result, the pump port 22E of the sleeve 22 is disconnected from the actuator port 22G, and the actuator port 22G is kept in a state of communication with the tank port 22F (initial state).

[0070] When the coil 3 is powered from the control device, a magnetic field (excitation force) is generated by the coil 3, and the plunger 9 is attracted to the anchor 5 by an attraction force corresponding to the current value supplied to the coil 3. At this time, the plunger 9 moves toward the anchor 5 side in the housing 4. Then, the plunger 9 stops at a position where the hydraulic pressure acting on the valve rod 23, the spring force of the return spring 24, and the attraction force of the anchor 5 are balanced.

[0071] The displacement of the plunger 9 is transmitted to the spool 23 via the operating pin 10, so that the spool 23 moves in the sliding hole 22A of the sleeve 22. As a result, the pump port 22E of the sleeve 22 communicates with the actuator port 22G, and the actuator port 22G is disconnected from the tank port 22F.

[0072] Thus, pressure oil is supplied to the hydraulic actuator (for example, the hydraulic pilot chamber of the directional control valve) via the solenoid valve 1. At this time, the working oil after passing through the filter 31 (the first filter 32 and the second filter 33) flows into the pump port 22E from the radially outer side of the sleeve 22 to the inner side. When the power supply to the coil 3 is stopped, the magnetic field generated by the coil 3 disappears, and the valve rod 23 returns to the initial state due to the spring force of the return spring 24.

[0073] Here, in the embodiment, both ends 33A and 33B in the circumferential direction of the second filter 33 wound on the outer peripheral side of the first filter 32 are fixed to the outer peripheral surface of the sleeve 22 (the bottom surface of the annular recessed portion 22H). In this case, both ends 33A and 33B in the circumferential direction of the second filter 33 are fixed between both ends 32A and 32B in the circumferential direction of the first filter 32, that is, the portion of the outer peripheral surface of the sleeve 22 exposed from the first filter 32. Therefore, in addition to being able to stably fix the first filter 32 to the outer peripheral surface of the sleeve 22, the second filter 33 can also be stably fixed to the outer peripheral surface of the sleeve 22.

[0074] Thus, the two filters 32 and 33 can be stably mounted on the sleeve 22. That is, in the embodiment, the two filters 32 and 33 with different mesh sizes can be fixed to the outer peripheral surface of the sleeve 22 at the portion where the filters 32 and 33 do not overlap each other. Therefore, the two filters 32 and 33 can be stably mounted on the outer peripheral surface of the sleeve 22.

[0075] According to the embodiment, the second filter 33 is wound around the outer peripheral surface of the sleeve 22 in an annular shape (O-shaped) over the entire circumference. Therefore, both ends 33A and 33B of the second filter 33 in the circumferential direction can be fixed together to the outer peripheral surface of the sleeve 22. As a result, compared with the case where both ends 33A and 33B of the second filter 33 in the circumferential direction are fixed separately, the labor and time (process) for fixing can be reduced.

[0076] In particular, according to the embodiment, the second filter 33 has a sufficiently fine component (filter material) and a fine mesh compared to the first filter 32. Therefore, even if the two ends 33A and 33B of the second filter 33 are fixed to the outer peripheral surface of the sleeve 22 by spot welding in an overlapping manner, the second filter 33 can be stably fixed to the outer peripheral surface of the sleeve 22.

[0077] According to the embodiment, the mesh of the first filter 32 is coarser than that of the second filter 33 and the strength of the first filter 32 is higher than that of the second filter 33. Therefore, when the liquid flows from the radially outer side of the sleeve 22 toward the inner side into the pump port 22E, the first filter 32 located on the inner diameter side can suppress the deformation of the second filter 33 located on the outer diameter side. Thus, the filtering performance of the second filter 33 can be ensured and the damage of the second filter 33 can be suppressed.

[0078] According to the embodiment, the first filter 32 and the second filter 33 are fixed to the outer peripheral surface of the sleeve 22 by welding. Therefore, the first filter 32 and the second filter 33 can be stably fixed to the outer peripheral surface of the sleeve 22 by welding.

[0079] According to the embodiment, the valve element of the solenoid valve 1 (valve portion 21 ) serving as the valve device is the spool 23 . Therefore, in the valve device (spool valve) using the spool 23 as the valve element, the plurality of filters 32 , 33 can be stably mounted on the sleeve 22 .

[0080] According to the embodiment, the valve column 23 as the valve core is displaced relative to the sleeve 22 by the actuator (solenoid part 2) driven by the supply of electricity. Therefore, in a valve device (solenoid valve, electromagnetic valve, electric valve) having an actuator (solenoid) driven by the supply of electricity, multiple filters 32, 33 can be stably installed on the sleeve 22.

[0081] In addition, in the embodiment, the mesh of the first filter 32 is coarser than the mesh of the second filter 33 and the first filter 32 has a higher strength against deformation than the second filter 33. However, this is not limited to this. For example, the second filter may be a filter with a larger mesh than the first filter and a higher strength against deformation. That is, the relationship (characteristics) of the density (e.g., filtering performance, filtering accuracy), strength, and thickness of the filter material (constituent component) of the first filter and the second filter may be opposite to that of the embodiment. In this case, the first filter and the second filter may be provided in the annular recess 22J of the opening of the box port 22F, for example, in a manner that covers the opening of the box port 22F.

[0082] That is, the second filter has a function as a reinforcement filter that reinforces the first filter on the outer diameter side of the first filter. The first filter has a function as a filter filter that blocks the passage of foreign matter in the working oil on the radial inner side of the second filter that serves as a reinforcement filter. Thus, when the working oil flows out of the box port 22F from the radial inner side of the sleeve 22 toward the outer side, the second filter can suppress the first filter from deforming toward the outer diameter side.

[0083] In this way, when the mesh of the second filter is coarser than that of the first filter and the strength of the second filter is higher than that of the first filter, when the liquid flows out of the port from the radial inner side to the outer side of the sleeve, the second filter located on the outer diameter side can suppress the deformation of the first filter located on the inner diameter side. In this way, the filtering performance of the first filter can be ensured and damage to the first filter can be suppressed.

[0084] In the embodiment, the second filter 33 is wound around the outer peripheral surface (bottom surface of the annular recess 22H) of the sleeve 22 in an annular shape (O shape) over the entire circumference. However, this is not limited to this. For example, Fig.10 As in the first modified example shown, the second filter 33 is wound around the outer periphery of the sleeve 22 in a notched annular shape (C-shape).

[0085] That is, the second filter 33 may be wound on the outer peripheral surface (bottom surface of the annular recess 22H) of the sleeve 22 in a state where a portion of the outer peripheral surface is exposed in the circumferential direction. In this case, the second filter 33 is wound on the outer peripheral side of the first filter 32, and the two ends 33A and 33B in the circumferential direction face each other in a state separated in the circumferential direction. Thus, the outer peripheral surface of the sleeve 22 is exposed between one end 33A and the other end 33B in the circumferential direction of the second filter 33.

[0086] According to the first modified example, the second filter 33 is wound on the outer peripheral surface (bottom surface of the annular recess 22H) of the sleeve 22 with a portion of the outer peripheral surface exposed in the circumferential direction. Therefore, when the third filter is wound on the outer peripheral side of the second filter 33, the third filter can also be stably fixed to the outer peripheral surface of the sleeve 22.

[0087] That is, in Fig.11 In the second modified example shown, the filter 31 has a third filter 37 in addition to the first filter 32 and the second filter 33. In this case, Fig.10 As shown in the first modified example, the second filter 33 is wound around the outer peripheral surface of the sleeve 22 with a portion of the outer peripheral surface in the circumferential direction exposed. In addition, the third filter 37 is wound around the outer peripheral side of the second filter 33 .

[0088] Both ends (not shown) of the third filter 37 in the circumferential direction are fixed to the portions of the outer circumferential surface of the sleeve 22 exposed from the first filter 32 and the second filter 33. In addition, the third filter 37 may be wound in an annular shape (O-shaped) over the entire circumference of the outer circumferential surface of the sleeve 22. Furthermore, the third filter 37 may be wound on the outer circumferential surface of the sleeve 22 in a state where a portion of the circumferential surface is exposed (in a notched annular shape, a C-shaped shape).

[0089] In this case, the first filter 32 and the third filter 37 can be filters with a coarser mesh than the second filter 33 and a higher strength against deformation than the second filter. For example, when the particle size of the captured particles (pollutants) captured by the second filter 33 is set to 1, the particle size of the captured particles (pollutants) captured by the first filter 32 and the third filter 37 can be 2 to 5 (more preferably 4 to 5). For example, when the pressure loss of the second filter 33 is set to 1, the pressure loss of the first filter 32 and the third filter 37 can be 0.2 to 0.4 (more preferably 0.25 or less).

[0090] For example, when the strength of the second filter 33 is set to 1, the strengths of the first filter 32 and the third filter 37 can be 15 to 25 (more preferably 20 or more). For example, when the thickness of the filter material of the second filter 33 is set to 1, the thickness of the filter material of the first filter 32 and the third filter 37 can be 2 to 5 (more preferably 2.5 or more).

[0091] According to the second modification, the third filter 37 wound around the outer circumference of the first filter 32 and the second filter 33 can have both ends of the circumferential direction fixed to the outer circumferential surface of the sleeve 22 (the bottom surface of the annular recess 22H). Fig.10The portion between the two ends 33A and 33B in the circumferential direction of the second filter 33 shown is a portion of the outer circumferential surface of the sleeve 22 exposed from the first filter 32 and the second filter 33 .

[0092] Therefore, in addition to the first filter 32 and the second filter 33 being stably fixed to the outer peripheral surface of the sleeve 22, the third filter 37 can also be stably fixed to the outer peripheral surface of the sleeve 22. Thus, the three filters 32, 33, 37 can be stably mounted on the sleeve 22.

[0093] Furthermore, according to the second modified example, the meshes of the first filter 32 and the third filter 37 are coarser than the meshes of the second filter 33, and the strength of the first filter 32 and the third filter 37 is higher than the strength of the second filter 33. Therefore, when the liquid flows from the radially outer side of the sleeve 22 toward the inner side into the port 22E, the first filter 32 located at the innermost diameter side can suppress the deformation of the second filter 33. Furthermore, when the liquid flows out of the port 22E from the radially inner side of the sleeve 22 toward the outer side, the third filter 37 located at the outermost diameter side can suppress the deformation of the second filter 33. Thus, regardless of the flow direction of the liquid in the port 22E, the filtering performance of the second filter 33 can be ensured and the damage of the second filter 33 can be suppressed.

[0094] exist Fig.11 In the second modified example shown, the case where the port 22E is covered by three filters 32, 33, and 37 is described as an example. However, the present invention is not limited thereto, and the number of filters may be four or more. In such a case, the remaining filters located inside the outer filter can be wound around the outer periphery of the sleeve in a notched circular ring shape (C-shaped), so that the outer filter arranged at the outermost radial side can be fixed to the outer peripheral surface of the sleeve.

[0095] exist Fig.11 In the second modified example shown, the case where the mesh of the first filter 32 and the third filter 37 is coarser than the mesh of the second filter 33 and the strength of the first filter 32 and the third filter 37 is higher than the strength of the second filter 33 is described as an example. However, this is not limited to this. For example, the first filter can also be a filter with a coarser mesh than the second filter and the third filter and a higher strength. In addition, the third filter can also be a filter with a coarser mesh than the second filter and the first filter and a higher strength. That is, the mesh density, strength, thickness, material and other characteristics of each filter wound on the sleeve can be set to ensure the required filtering performance, pressure loss, strength, etc. The same is true for the case where the number of filter sheets is set to four or more.

[0096] In the embodiment, the valve core of the solenoid valve 1 as the valve device is set as the valve column 23. In addition, in the embodiment, the valve device is set as the solenoid valve 1 in which the valve column 23 as the valve core is displaced relative to the sleeve 22 by the solenoid part 2 (actuator) driven by the supply of electric power. However, this is not limited to this. For example, Fig.12 As in the third modified example shown in FIG. 1 , the valve device is set as a safety valve 51. That is, Fig.12 A third modified example is shown.

[0097] Fig.12 In the embodiment, the safety valve 51 as a valve device includes a sleeve 52 , a main poppet 53 as a valve element, and a filter 31 . Fig.12 The safety valve 51 is a safety valve for preventing overload of the hydraulic cylinder 71. The sleeve 52 is provided with a port 54 and a valve core hole 55 communicating with the port 54. The main poppet 53 is inserted into the valve core hole 55 of the sleeve 52. The main poppet 53 moves axially in the valve core hole 55. The filter 31 is wound circumferentially at a position corresponding to the port 54 on the outer peripheral side of the sleeve 52.

[0098] The filter 31 includes a first filter 32, a second filter 33, and a third filter 37. The first filter 32 and the second filter 33 are wound on the outer peripheral surface of the sleeve 52 in a state where a portion of the outer peripheral surface is exposed in the circumferential direction. Both ends of the first filter 32 and the second filter 33 in the circumferential direction are fixed to the outer peripheral surface of the sleeve 52. The third filter 37 is wound on the outer peripheral side of the first filter 32 and the second filter 33. Both ends of the third filter 37 in the circumferential direction are fixed to the portions exposed from the first filter 32 and the second filter 33. In this case, both ends of the third filter 37 in the circumferential direction are fixed to the portion of the outer peripheral surface of the sleeve 52 between the two ends of the first filter 32 and the second filter 33 in the circumferential direction.

[0099] like Fig.12 As shown, for example, one axial end side of the sleeve 52 ( Fig.12 The opening of the bottom side oil circuit 72 (on the right end side) is connected to the bottom side oil circuit 72 which is the actuator oil circuit. The bottom side oil circuit 72 connects the bottom side oil chamber 71A of the hydraulic cylinder 71 and the directional control valve 73. The directional control valve 73 is switched by supplying a pilot pressure to the hydraulic pilot chambers 73A and 73B. Thus, the directional control valve 73 supplies or discharges the pressure oil ejected from the hydraulic source to the bottom side oil chamber 71A or the rod side oil chamber 71B of the hydraulic cylinder 71. In addition, although not shown in the figure, the rod side oil circuit 74 which is the actuator oil circuit connecting the rod side oil chamber 71B of the hydraulic cylinder 71 and the directional control valve 73 is also connected to the same safety valve 51 as the bottom side oil circuit 72.

[0100] The port 54 of the sleeve 52 is connected to the tank 76 via the tank oil passage 75. When the pressure in the back pressure chamber 58 connected to the oil chamber 56 of the main poppet 53 via the orifice 57 which is a small hole is lower than the safety setting pressure, the axial end side ( Fig.12 The right end side of the pilot poppet 60 abuts (sits) on the cylindrical main valve seat member 59. Fig.12 The right end side of the bottom oil passage 72 is also in contact with (seated on) the cylindrical pilot valve seat member 61. In this case, the bottom oil passage 72 is disconnected from the tank oil passage 75.

[0101] On the other hand, if the pressure in the oil chamber 56 and the back pressure chamber 58 of the main poppet 53 rises, the pilot poppet 60 overcomes the pilot poppet spring 62 and moves to the other side in the axial direction ( Fig.12 If the main poppet 53 moves from the main valve seat member 59 to the other side in the axial direction ( Fig.12 When the bottom oil passage 72 is released (left side) from the main valve seat, the pressure oil of the bottom oil passage 72 is guided to the port 54 through the main poppet 53 and the main valve seat member 59. Thus, the pressure oil of the bottom oil passage 72 can be released (overflowed) to the tank oil passage 75.

[0102] Furthermore, the safety valve 51 also has a function as a negative pressure prevention valve for the hydraulic cylinder 71 (hydraulic actuator). For example, if the pressure of the tank oil circuit 75 is higher than the pressure of the bottom side oil circuit 72, the hydraulic pressure acting on the main valve seat component 59 overcomes the force of the biasing spring 63, and the main valve seat component 59 is separated from the main poppet 53. As a result, the working oil can be drawn from the tank 76 side to the hydraulic cylinder 71 side (bottom side oil circuit 72) via the tank oil circuit 75 and the port 54. In this way, the safety valve 51 also has a negative pressure prevention function, so the direction of the working oil flowing through the port 54 is opposite during the overflow action and the negative pressure prevention action. That is, a two-way flow is generated at the port 54. Therefore, in the third modified example, the filter 31 is set to a three-layer structure of the first filter 32, the second filter 33 and the third filter 37.

[0103] The third modification example is also similar to the embodiment, the first modification example, and the second modification example, and multiple filters 32, 33, and 37 can be stably mounted on the sleeve 52. In particular, according to the third modification example, the valve element of the safety valve 51 that becomes the valve device is a poppet (main poppet 53). Therefore, in the valve device (poppet valve) using a poppet (conical poppet, spherical poppet) as the valve element, multiple filters 32, 33, and 37 can be stably mounted on the sleeve 52.

[0104] In the embodiment and each modified example, the electromagnetic valve 1 and the safety valve 51 are shown as examples of valve devices equipped with the filter 31. However, the filter 31 of the embodiment and each modified example can be assembled on various valve devices (sliding valve, poppet valve) such as a pressure control valve, a flow control valve, a safety valve, and a throttle valve. In addition, the valve device is not limited to a solenoid valve having an actuator driven by the supply of electricity, but can also be a valve device without an actuator. In addition, the port covered by the filter can be a port through which liquid flows. That is, the port covered by the filter is not limited to a pump port, a tank port, and an actuator port.

[0105] The embodiments and modifications are merely examples, and it is of course possible to partially replace or combine the structures shown in the different embodiments and modifications.

[0106] Explanation of symbols

[0107] 1—solenoid valve (valve device), 2—solenoid part (actuator), 21—valve part, 22—sleeve, 22A—sliding hole (valve core hole), 22E—pump port, 23—valve column (valve core), 31—filter, 32—first filter, 33—second filter, 32A—one end, 32B—the other end, 33A—one end, 33B—the other end, 34, 35, 36—spot welding (welding), 37—third filter, 51—safety valve (valve device), 52—sleeve, 53—main poppet (poppet, valve core), 54—port, 55—valve core hole.

Claims

1. A valve device comprising: A sleeve having a port and a valve core hole communicating with the port; a valve core inserted into the valve core hole of the sleeve and moving axially in the valve core hole; and A filter is wound circumferentially on the outer peripheral side of the sleeve and at a position corresponding to the port. The valve device is characterized in that The above filter has: A first filter is wound on the outer peripheral surface of the sleeve in a state where a portion of the outer peripheral surface in a circumferential direction is exposed, and both ends in a circumferential direction are fixed to the outer peripheral surface of the sleeve; and The second filter is wound around the outer circumference of the first filter and has both ends in the circumferential direction fixed to a portion of the outer circumferential surface of the sleeve that is exposed from the first filter between the both ends in the circumferential direction of the first filter.

2. The valve device according to claim 1, characterized in that The second filter is wound around the outer peripheral surface of the sleeve in a state where a portion of the outer peripheral surface in a circumferential direction is exposed.

3. The valve device according to claim 1, characterized in that The second filter is wound around the entire outer peripheral surface of the sleeve.

4. The valve device according to claim 1, characterized in that The mesh of the first filter is coarser than that of the second filter, and the strength of the first filter is higher than that of the second filter.

5. The valve device according to claim 1, characterized in that The mesh of the second filter is coarser than that of the first filter and the strength of the second filter is higher than that of the first filter.

6. The valve device according to claim 2, characterized in that The above filter has: the first filter mentioned above; the second filter as described above; and The third filter is wound on the outer peripheral side of the second filter in a state where it is exposed over the entire circumference of the outer peripheral surface of the sleeve or a portion of the circumferential direction of the outer peripheral surface of the sleeve, and its two circumferential ends are fixed to the portions of the outer peripheral surface of the sleeve that are exposed from the first filter and the second filter.

7. The valve device according to claim 6, characterized in that The meshes of the first filter and the third filter are coarser than the mesh of the second filter, and the strengths of the first filter and the third filter are higher than the strength of the second filter.

8. The valve device according to claim 1, characterized in that The first filter and the second filter are fixed to the outer peripheral surface of the sleeve by welding.

9. The valve device according to claim 1, characterized in that The valve core is a valve column or a poppet.

10. The valve device according to claim 1, characterized in that The valve element is displaced relative to the sleeve by an actuator driven by supply of electric power.

Images