Solenoid valve and method for manufacturing solenoid valve

Abstract

A solenoid valve (V) according to the present invention comprises: a bottomed cylindrical cap (1) that is attached to an opening of a valve hole (38b1) of a housing (38b), the housing having the valve hole (38b1) opening from one end side; a solenoid (S) that is accommodated in the cap (1); a valve seat member (2) that has a port (2a), is accommodated in the valve hole (38b1), and is aligned in the radial direction of the solenoid (S) by the solenoid (S); and a valve element (3) that can open and close the port (2a) of the valve seat member (2) and that is driven by the solenoid (S). The solenoid (S) and the valve seat member (2) are sandwiched between the cap (1) and the bottom part (38b4) of the valve hole (38b1) of the housing (38b) and fixed to the housing (38b).

Description

Solenoid valve and method of manufacturing the same

[0001] The present invention relates to a solenoid valve and a method for manufacturing the solenoid valve.

[0002] The solenoid valve is used, for example, as a damping valve for a shock absorber to adjust the damping force of the shock absorber.

[0003] Such a solenoid valve, as disclosed in JP2022-055571A, for example, comprises a cylindrical housing, a cylindrical cap that is screwed to the inner periphery of the housing and houses a solenoid inside, a valve case that is screwed to the inner periphery of the cap, a valve seat member that is sandwiched between the valve case and the cap, and a valve disc that is capable of being seated on and removed from the valve seat member and is biased by a solenoid to open and close a port provided in the valve seat member, and the resistance applied to the flow of hydraulic oil passing through the port as the shock absorber expands and contracts is changed by adjusting the current supplied to the solenoid.

[0004] JP2022-055571A

[0005] Conventional solenoid valves employ a structure in which a valve case, which houses a valve seat member and a valve body, is screwed to a cap to apply axial force to the valve seat member, fixing it within the valve case, and the cap is screwed to a housing to fix the solenoid and valve seat member.

[0006] Therefore, when assembling a solenoid valve, the screw connection work is required twice, which makes the assembly work time-consuming, and because there are two screw connection parts in the part where pressure is applied, there is a possibility that the screw connection parts will loosen when pressure is applied during use of the solenoid valve.In addition, because the shape of the screw connection parts is limited, there is a limit to how much miniaturization can be made with conventional solenoid valves that have two screw connection parts.

[0007] Therefore, an object of the present invention is to provide a solenoid valve that can reduce the possibility of loosening, is easy to assemble, and can be made compact, and a method for manufacturing the solenoid valve.

[0008] In order to solve the above problems, the solenoid valve of the present invention comprises a bottomed cylindrical cap attached to the opening of a valve hole of a housing having a valve hole that opens from one end, a solenoid housed in the cap, a valve seat member having a port that is housed in the valve hole and is centered radially of the solenoid by the solenoid, and a valve body that can open and close the port in the valve seat member and is driven by the solenoid, and is characterized in that the solenoid and valve seat member are clamped between the bottom of the valve hole of the housing and the cap and fixed to the housing.

[0009] In a solenoid valve configured in this manner, by attaching the cap to the housing, the solenoid and valve seat member can be clamped and fixed between the cap and the bottom of the valve hole in the housing, and the valve seat member is aligned with the solenoid.This makes it possible to fix the valve seat member to the cap and align the valve seat member with the solenoid without using multiple screw connections, and the solenoid valve can be fixed to the housing without using multiple screw connections as in conventional solenoid valves.

[0010] Furthermore, a method for manufacturing a solenoid valve of the present invention is a method for manufacturing a solenoid valve comprising: a cylindrical cap with a bottom that is attached to the opening of a valve hole of a housing having a valve hole that opens from one end; a solenoid housed in the cap; a valve seat member that has a port and is housed in the valve hole and is centered radially of the solenoid by the solenoid; a valve disc that can open and close the port in the valve seat member and is driven by the solenoid; and a cylindrical case with a bottom that houses the valve seat member and the valve disc inside, the method comprising the steps of: housing the solenoid in the cap; housing the valve seat member and the valve disc in the case; inserting the case into the cap and temporarily fastening the case to the cap; and inserting the cap with the temporarily fastened case into the valve hole and joining the cap to the housing. Furthermore, another method for manufacturing a solenoid valve according to the present invention is a method for manufacturing a solenoid valve including: a bottomed, cylindrical cap attached to the opening of a valve hole of a housing having a valve hole that opens from one end; a solenoid housed in the cap; a bottomed, cylindrical valve seat member having a port and housed in the valve hole and centered radially of the solenoid by the solenoid; and a valve disc capable of opening and closing the port in the valve seat member and driven by the solenoid, the method comprising the steps of: housing the solenoid in the cap; housing the valve disc in the valve seat member; inserting the valve seat member into the cap and temporarily fixing the valve seat member to the cap; and inserting the cap with the temporarily fixed valve seat member into the valve hole and joining the cap to the housing.

[0011] According to the method for manufacturing a solenoid valve configured in this manner, the solenoid valve can be manufactured simply by providing a screw connection between the cap and the housing, which reduces the possibility of loosening, makes assembly easier, and enables miniaturization.In addition, each part of the solenoid valve can be assembled together, making the assembly of the solenoid valve even easier.

[0012] Fig. 1 is a longitudinal cross-sectional view of a shock absorber to which a solenoid valve according to an embodiment of the present invention is applied, Fig. 2 is an enlarged cross-sectional view of the solenoid valve according to the embodiment of the present invention, and Fig. 3 is an enlarged cross-sectional view of a solenoid valve according to a first modified example of the embodiment of the present invention.

[0013] 1 and 2, a solenoid valve V in one embodiment includes a cylindrical cap 1 with a bottom attached to an opening of a valve hole 38b1 of a housing 38b, a solenoid S housed within the cap 1, a valve seat member 2 having a port 2a housed within the valve hole 38b1, a valve element 3 that can open and close the port 2a in the valve seat member 2 and is driven by the solenoid S, and a cylindrical case 4 with a bottom housed therein and that houses the valve seat member 2 and the valve element 3. The solenoid valve V is applied to a shock absorber D and used as a damping valve for adjusting the compression damping force of the shock absorber D.

[0014] Hereinafter, a detailed description will be given of the configuration of the solenoid valve V of this embodiment and the shock absorber D to which the solenoid valve V is applied. First, the shock absorber D will be described. 1 , the shock absorber D includes a cylinder 31, a piston rod 32 movably inserted into the cylinder 31 in the axial direction, a piston 33 dividing the interior of the cylinder 31 into an extension-side chamber R1 and a compression-side chamber R2, an extension-side damping passage 33 a and a compression-side damping passage 33 b provided in the piston 33 and communicating between the extension-side chamber R1 and the compression-side chamber R2, an extension-side damping valve 34 fixed to the piston rod 32 and opening and closing the extension-side damping passage 33 a, a compression-side damping valve 35 fixed to the piston rod 32 and opening and closing the compression-side damping passage 33 b, a tank 36 provided on the side of the cylinder 31, an outer tube 37 covering the outer periphery of the cylinder 31, an upper cap 38 closing the upper end of the cylinder 31 and connecting the cylinder 31 and the tank 36, a solenoid valve V attached to a housing 38 b provided in the upper cap 38, and a suspension spring 39 interposed between the cylinder 31 and the piston rod 32.

[0015] Below, we will explain each part of the shock absorber D. The cylinder 31 is cylindrical and has a hole 31a at its lower end in Figure 1 that connects the inside and outside, and is inserted into the outer tube 37. An annular gap is formed between the cylinder 31 and the outer tube 37, and is connected to the inside of the cylinder 31 by the hole 31a provided in the cylinder 31.

[0016] 1, the upper ends of both the cylinder 31 and the outer tube 37 are closed by upper caps 38, and an annular rod guide 40 is attached to the inner periphery of the lower ends of the cylinder 31 and the outer tube 37. The outer tube 37 is provided with a threaded portion 37a on the outer periphery at the upper end in FIG. 1, onto which an annular upper suspension spring bearing 41 and a nut 42 are threadedly engaged, and a hole 37b provided on the upper side in FIG. 1, closer to the tip end than the threaded portion 37a, for communicating the inside and outside of the outer tube 37.

[0017] The upper suspension spring bearing 41 can be moved up and down relative to the outer tube 37 by rotating the screw portion 37a in the manner of a feed screw, and is fixed to the screw portion 37a by tightening a nut 42.

[0018] The piston rod 32 has a small-diameter portion 32a at its upper end that is smaller in diameter than the lower portion, and a bracket 32b at its lower end that can be connected to the body or wheel of a vehicle (not shown), and an annular lower suspension spring bearing 32c stacked above the bracket 32b. A cylindrical cushion 43 that abuts against the upper end of the bracket 32b is attached to the outer periphery of the lower end of the piston rod 32 in FIG.

[0019] The piston rod 32 is inserted into the cylinder 31 through the inner periphery of the rod guide 40, and its outer periphery is in sliding contact with the inner periphery of a cylindrical bushing 40a fixed to the inner periphery of the rod guide 40, allowing the piston rod 32 to move in the axial direction while being guided by the rod guide 40. In addition to the bushing 40a, an annular seal member 40b that slides against the outer periphery of the piston rod 32 is provided on the inner periphery of the rod guide 40, and the interior of the cylinder 31 is sealed by the seal member 40b. In this embodiment, the seal member 40b is provided on the inner periphery of the rod guide 40, but a seal member that seals between the cylinder 31 and the piston rod 32 may be provided below the rod guide 40, independent of the rod guide 40.

[0020] A suspension spring 39, which is a coil spring disposed on the outer periphery of the outer tube 37 and the piston rod 32, is disposed between the upper suspension spring bearing 41 and the lower suspension spring bearing 32c, and the suspension spring 39 constantly biases the piston rod 32 in a direction to retract outward from the cylinder 31, that is, in a direction to extend the shock absorber D. When the shock absorber D equipped with the suspension spring 39 in this manner is disposed between the body and wheels of a vehicle (not shown), the vehicle body is elastically supported by the suspension spring 39.

[0021] Furthermore, when the piston rod 32 penetrates deep into the cylinder 31 and the shock absorber D contracts to the vicinity of the stroke end on the contraction side, the cushion 43 attached to the outer periphery of the piston rod 32 comes into contact with the rod guide 40 and is compressed, generating a resilient force that suppresses the contraction of the shock absorber D. Note that the shock absorber D of this embodiment employs a structure in which the cushion 43 comes into contact with the rod guide 40, but a structure in which an annular stopper facing the cushion 43 is provided below the rod guide 40 in FIG. 1 and the cushion 43 comes into contact with the stopper and is compressed may also be employed.

[0022] An annular piston 33 is attached to the small diameter portion 32a at the upper end of the piston rod 32. The piston 33 is annular and is attached to the outer periphery of the small diameter portion 32a of the piston rod 32 together with an extension side damping valve 34 and a compression side damping valve 35 by a piston nut 44.

[0023] When the piston 33 is inserted into the cylinder 31, the piston 33 divides the interior of the cylinder 31 into an extension-side chamber R1 and a compression-side chamber R2 filled with a liquid, and can move axially within the cylinder 31 together with the piston rod 32. The liquid filled in the extension-side chamber R1 and the compression-side chamber R2 is, for example, hydraulic oil, but may be a liquid other than hydraulic oil.

[0024] 1, the piston 33 has an extension-side damping passage 33a and a compression-side damping passage 33b that penetrate along the axial direction, and is inserted into the cylinder 31 so as to be axially movable, dividing the interior of the cylinder 31 into an extension-side chamber R1 and a compression-side chamber R2. In this way, the extension-side chamber R1 divided inside the cylinder 31 by the piston 33 is in communication with the annular gap between the cylinder 31 and the outer tube 37 via a hole 31a provided in the cylinder 31.

[0025] In the shock absorber D of this embodiment, the extension side damping valve 34 is a laminated leaf valve that is configured by stacking a plurality of annular plates, and that has its inner periphery fixed to the outer periphery of the small diameter portion 32a of the piston rod 32 and that is stacked on the upper end of the piston 33 in FIG. 2, and the inner periphery is fixed to the piston rod 32 so that the outer periphery is allowed to bend. Thus, the extension side damping valve 34 has its outer periphery as a free end and is stacked on the piston 33 to close the extension side damping passage 33a, and when the outer periphery is bent to open the extension side damping passage 33a, the extension side damping passage 33a opens and provides resistance to the flow of fluid from the extension side chamber R1 to the compression side chamber R2.

[0026] In the shock absorber D of this embodiment, the compression side damping valve 35 is a laminated leaf valve that is configured by stacking a plurality of annular plates, has its inner periphery fixed to the outer periphery of the small diameter portion 32a of the piston rod 32, and is stacked on the lower end of the piston 33 in FIG. 2, and the inner periphery is fixed to the piston rod 32 so that bending of the outer periphery is permitted. Therefore, the compression side damping valve 35 has its outer periphery as a free end and is stacked on the piston 33 to close the compression side damping passage 33b, and when the outer periphery is bent to open the compression side damping passage 33b, the compression side damping passage 33b opens and provides resistance to the flow of fluid from the compression side chamber R2 to the extension side chamber R1.

[0027] The compression side damping valve 35, piston 33, and extension side damping valve 34 configured in this manner are assembled in this order to the outer periphery of the small diameter portion 32 a of the piston rod 32, and then fixed to the piston rod 32 by a piston nut 44 that is screwed onto the tip of the small diameter portion 32 a.

[0028] Next, the upper cap 38 that closes the upper part of the cylinder 31 in Figure 1 includes a cap portion 38a that is attached to the upper end of the cylinder 31 in Figure 1, a cylindrical housing 38b that accommodates the solenoid valve V, and a connection portion 38c that extends horizontally in Figure 1 from the side of the cap portion 38a and is connected to the housing 38b.

[0029] The cap portion 38a is cylindrical with a top having a top portion 38a1 and a cylindrical portion 38a2, and is provided with a step portion 38a3 formed on the inner periphery of the cylindrical portion 38a2 on the top side and abutting the upper end of the cylinder 31 in Figure 1, and a threaded portion 38a4 formed on the inner periphery of the cylindrical portion 38a2 on the lower side in Figure 1 and threadedly coupled to the threaded portion 37a of the outer tube 37, thereby closing off the upper end of the cylinder 31 and the upper end of the outer tube 37, and is provided with a bracket 38a5 above the top portion 38a1 in Figure 1 that can be connected to the body of a vehicle (not shown).

[0030] A flange 31b is provided on the outer periphery of the upper end of the cylinder 31, which abuts against the step portion 38a3 of the cap portion 38a, and an O-ring 31c attached to the outer periphery of the flange 31b is tightly attached to the inner periphery of the tubular portion 38a2 of the cap portion 38a, preventing the annular gap between the cylinder 31 and the outer tube 37 from communicating with the compression side chamber R2 through the gap between the cylinder 31 and the step portion 38a3. Then, the cylinder 31 is inserted into the cap portion 38a until the upper end of the cylinder 31 abuts the step portion 38a3, and the outer tube 37 is inserted into the cap portion 38a while being screwed in, and the upper end of the outer tube 37 abuts against the flange 31b of the cylinder 31 and tightened.The outer tube 37 is fixed to the cap portion 38a by the threaded connection between the screw portion 37a and the screw portion 38a4, and the cylinder 31 is clamped between the upper end of the outer tube 37 and the step portion 38a3, so that the cylinder 31 is also fixed to the cap portion 38a at the same time.

[0031] 1, a hose 45 connected to the tank 36 is attached to the cap portion 38a, and the compression-side chamber R2 is communicated with the inside of the tank 36 through the hose 45. In this embodiment, the tank 36 includes a topped cylindrical main body 36a, a cap 36b that closes the opening of the main body 36a, and a free piston 36c that is housed within the main body 36a and is axially movable to divide the inside of the tank 36 into a liquid chamber L and an air chamber G. In this embodiment, the inside of the tank 36 is divided into the liquid chamber L and the air chamber G by the free piston 36c, but the liquid chamber L and the air chamber G may be divided by a flexible elastic partition such as a diaphragm or a bladder, or a bellows, instead of the free piston 36c. A damping passage 46 and a suction passage 47 are provided at the top of the main body 36a of the tank 36, connecting the liquid chamber L to the compression side chamber R2 in the cylinder 31 via a hose 45. The damping passage 46 is also provided with a compression side main damping valve 48 that provides resistance to the flow of liquid from the compression side chamber R2 to the liquid chamber L, and a suction check valve 49 that is provided in the suction passage 47 and only allows the flow of liquid from the liquid chamber L to the compression side chamber R2.

[0032] Returning to the previous section, the connecting portion 38c protrudes horizontally from the side of the cap portion 38a to the left in FIG. 1, and is integrally connected to the housing 38b that continues below the tip.

[0033] The housing 38b is cylindrical and is integrated with the lower end of the connecting portion 38c, and has a valve hole 38b1 that opens from the lower side in Figures 1 and 2. The valve hole 38b1 has a small diameter portion on the back side, a large diameter portion 38b2 on the opening side, and a small diameter portion 38b3 on the back side. Furthermore, a screw groove is formed on the inner periphery of the large diameter portion 38b2 of the valve hole 38b1 of the housing 38b, on the side of the small diameter portion 38b3.

[0034] The valve hole 38b1 is connected to the compression-side chamber R2 in the cylinder 31 through a passage 38c1 that is provided in the connecting portion 38c and opens from the upper end in FIG. 2 that corresponds to a bottom 38b4 of the valve hole 38b1 and opens to the inner periphery of the tubular portion 38a2 of the cap portion 38a. The valve hole 38b1 is also connected to the expansion-side chamber R1 through a passage 38c2 that is provided in the connecting portion 38c and opens from the large-diameter portion 38b2 of the valve hole 38b1 and opens to the inner periphery of the tubular portion 38a2 of the cap portion 38a, the hole 37b of the outer tube 37, the annular gap between the cylinder 31 and the outer tube 37, and the hole 31a of the cylinder 31. In this way, the valve hole 38b1 is connected to the expansion-side chamber R1 and the compression-side chamber R2 through the passages 38c1 and 38c2.

[0035] A solenoid valve V is attached to the housing 38b. As described above, the solenoid valve V includes the cylindrical cap 1 with a bottom attached to the opening of the valve hole 38b1 of the housing 38b, the solenoid S housed in the cap 1, the valve seat member 2 having the port 2a housed in the valve hole 38b1, the valve element 3 that is driven by the solenoid S and can open and close the port 2a in the valve seat member 2, and the cylindrical case 4 with a bottom housed therein the valve seat member 2 and the valve element 3.

[0036] As shown in Fig. 2, the cap 1 is cylindrical and includes a bottom 1a and a cylindrical portion 1b extending from the outer periphery of the bottom 1a. The cap 1 has a through-hole 1a1 penetrating the center of the bottom 1a, a threaded portion 1b1 formed on the outer periphery of the upper end of the cylindrical portion 1b in Fig. 2, and an annular groove 1b2 formed on the outer periphery of the cylindrical portion 1b directly below the threaded portion 1b1. An O-ring 50 is fitted in the annular groove 1b2 of the cap 1. An annular groove 1b3, into which a C-shaped retaining ring 6 is fitted, is formed along the circumferential direction on the inner periphery of the cylindrical portion 1b at the upper end in Fig. 2.

[0037] Next, as shown in Figure 2, the solenoid S comprises a frame 60 formed of a cylindrical magnetic material with a bottom, a cylindrical coil 61 housed in the frame 60, a cylindrical first fixed iron core 62 with a bottom that is inserted into the coil 61 at the bottom side of the frame 60, a cylindrical second fixed iron core 63 that is inserted into the coil 61 from the open end side of the frame 60 across an annular spacer 68 that forms an air gap together with the first fixed iron core 62, a movable iron core 64 that is housed inside the first fixed iron core 62 between the first fixed iron core 62 and the second fixed iron core 63 and is attracted towards the second fixed iron core 63 when current is passed through the coil 61, and a push rod 65 that is connected to the movable iron core 64 and movably inserted into the second fixed iron core 63.

[0038] The coil 61 is housed inside the frame 60 and can receive current through a hole 60a provided in the bottom of the frame 60 and a cable 66 inserted into a through-hole 1a1 in the bottom 1a of the cap 1 and connected to an external power source not shown.

[0039] The first stationary iron core 62 is cylindrical with a bottom, and is inserted into the inner periphery of the coil 61 with its bottom side facing the bottom side of the frame 60 and its cylindrical part facing the opening side of the frame 60. The second stationary iron core 63 is cylindrical and is inserted closer to the opening side of the frame 60 than the first stationary iron core 62 within the coil 61, and its end face faces the cylindrical part of the first stationary iron core 62 with a gap therebetween.

[0040] The second stationary core 63 is cylindrical and includes an annular protrusion 63a on the outer periphery of the lower end in Fig. 2 that faces the cylindrical portion of the first stationary core 62 in the axial direction, a flange 63b that is provided on the outer periphery of the open end of the frame 60 and fits into the inner periphery of the cylindrical portion of the frame 60, and an annular recess 63c on the inner periphery of the upper end in Fig. 2. An annular groove 63b1 that accommodates an O-ring 67 is provided on the outer periphery of the flange 63b of the second stationary core 63, and when the second stationary core 63 is inserted into the frame 60, the O-ring 67 comes into close contact with the inner periphery of the cylindrical portion of the frame 60, sealing the gap between the second stationary core 63 and the frame 60.

[0041] The movable iron core 64 is slidably inserted into the cylindrical portion of the first fixed iron core 62 and is positioned between the first fixed iron core 62 and the second fixed iron core 63, and when seated on the bottom of the first fixed iron core 62, the outer periphery of the second fixed iron core side end is slightly radially opposed to the annular protrusion 63a of the second fixed iron core 63.

[0042] Therefore, a magnetic path is formed by the frame 60, the first fixed iron core 62, the movable iron core 64 and the second fixed iron core 63, and when current is passed through the coil 61, the movable iron core 64 is attracted to the second fixed iron core 63 and attempts to move so as to increase the opposing area with the annular protrusion 63a, thereby forcing the push rod 65 in a direction to withdraw from the frame 60.

[0043] The valve seat member 2 is cylindrical and has four ports 2a spaced apart along the circumferential direction to communicate between the inside and outside. The valve seat member 2 fits snugly into the annular recess 63c of the second fixed core 63 and is aligned radially by the solenoid S.

[0044] The valve disc 3 is cylindrical with a bottom, with its outer periphery in sliding contact with the inner periphery of the valve seat member 2. Its axial length is shorter than that of the valve seat member 2, allowing axial movement within the valve seat member 2. The valve disc 3 has a hole 3a at its bottom and four ports 3b spaced apart along the circumferential direction of the cylindrical portion, providing communication between the inside and outside. When the valve seat member 2 and the valve disc 3 are viewed axially, ports 2a and 3b are positioned in the same circumferential phase. When the bottom of the valve disc 3 abuts against the bottom surface of the annular recess 63c of the second fixed iron core 63 of the solenoid S, port 3b is positioned lower in FIG. 2 than port 2a of the valve seat member 2. As the valve disc 3 moves upward in FIG. 2 from the position where its bottom abuts against the second fixed iron core 63 relative to the valve seat member 2, port 3b eventually faces port 2a. When the two ports reach the same height, they face each other and the degree of overlap is maximized.

[0045] Therefore, by moving the valve disc 3 in the axial direction within the valve seat member 2, the communication state between port 2a and port 3b can be changed from a state in which port 2a is completely closed to a state in which port 2a is fully opened. The bottom of the valve disc 3 faces the second fixed iron core 63 of the solenoid S and can abut against the push rod 65, so that by supplying current to the coil 61 of the solenoid S, the valve disc 3 can be pressed and the position of the valve disc 3 can be changed relative to the valve seat member 2. Although there are four ports 2a and four ports 3b, the number of ports can be changed as long as they are the same, and the shapes of ports 2a and 3b can also be changed as desired.

[0046] The case 4 is cylindrical and has a bottom, and includes a hole 4b provided in the bottom 4a, a flange 4d provided on the outer periphery of the tip of the tubular portion 4c, an annular protrusion 4e provided on the outer periphery of the flange 4d at the lower end in Figure 2 and protruding radially outward, four notches 4f that penetrate both the flange 4d and the annular protrusion 4e in the radial direction and lead into the tubular portion 4c, and an annular groove 4g provided on the outer periphery of the upper end in Figure 2 of the tubular portion 4c.

[0047] The inner diameter of the cylindrical portion 4c in the case 4 is larger than the outer diameter of the valve seat member 2, and when the valve seat member 2 is housed in the cylindrical portion 4c, a gap is provided between the cylindrical portion 4c and the valve seat member 2 to provide sufficient play.

[0048] In addition, the outer diameter of the annular protrusion 4e, which has the largest outer diameter of the case 4, is smaller than the inner diameter of the cylindrical portion 1b of the cap 1, and when the case 4 is inserted into the cap 1, the case 4 is loosely fitted into the cap 1 and is allowed to move in the axial direction.

[0049] Then, the case 4 is inserted into the cap 1 from the annular protrusion 4e side, and the annular protrusion 4e is positioned below the annular groove 1b3 in the cap 1. Then, the retaining ring 6 is attached to the annular groove 1b3. Since the inner diameter of the retaining ring 6 is smaller than the outer diameter of the annular protrusion 4e but larger than the outer diameter of the flange 4d, the case 4 is temporarily secured by the retaining ring 6, preventing it from falling off the cap 1 while allowing it to move axially relative to the cap 1.

[0050] The case 4 contains a valve seat member 2, a valve element 3, and a coil spring 5, and the case 4, together with the valve seat member 2, the valve element 3, and the coil spring 5 housed therein, is temporarily assembled to the cap 1 by a retaining ring 6. When the annular protrusion 4e abuts against the retaining ring 6 and movement of the case 4 in the retracting direction relative to the cap 1 is restricted, a gap is generated between the upper end of the valve seat member 2, the lower end of which in FIG. 2 abuts against the bottom of the annular recess 63c of the second fixed iron core 63 of the solenoid S, and the bottom 4a of the case 4. Furthermore, when the upper end of the valve seat member 2 in FIG. 2 abuts against the inner surface of the bottom 4a of the case 4, a gap is generated between the lower end of the flange 4d of the case 4 in FIG. 2 and the frame 60 and second fixed iron core 63 of the solenoid S, so that the lower end of the flange 4d in FIG. 2 does not abut against the frame 60 and second fixed iron core 63. Therefore, when the case 4 housing the valve seat member 2 is temporarily fixed to the cap 1 housing the solenoid S by the retaining ring 6, the case 4 can move slightly in the axial direction.

[0051] Furthermore, as described above, the inner diameter of the cylindrical portion 4c of the case 4 is larger than the outer diameter of the valve seat member 2, and when the valve seat member 2 is housed in the case 4 and temporarily fixed to the cap 1 with the retaining ring 6, even if there is a misalignment between the axial centers of the valve seat member 2, which is radially aligned by the solenoid S, and the case 4, the case 4 does not interfere with the valve seat member 2 and does not affect the radial position of the valve seat member 2 relative to the solenoid S.

[0052] The inner diameter of the inner periphery of the cylindrical portion 4c of the case 4 facing the port 2a of the valve seat member 2 is made sufficiently larger than the outer periphery of the valve seat member 2 so as not to provide resistance when the liquid passes through the annular gap between the inner periphery of the cylindrical portion 4c facing the port 2a of the valve seat member 2 and the outer periphery of the valve seat member 2.

[0053] The inner diameter of the hole 4b in the bottom 4a of the case 4 is smaller than the inner diameter of the valve disc 3, allowing a coil spring 5 to be interposed between the bottom 4a and the valve disc 3. The coil spring 5 is sandwiched in a compressed state between the upper end of the cylindrical portion of the valve disc 3 in FIG. 2 and the bottom 4a of the case 4, constantly urging the valve disc 3 and the movable iron core 64 downward in FIG. 2. When the solenoid S is not energized and does not apply thrust to the valve disc 3, the valve disc 3 abuts against the second fixed iron core 63 and the movable iron core 64 abuts against the bottom of the first fixed iron core 62. Four notches 4f are provided at equal intervals around the circumference of the case 4, ensuring communication between the inside and outside of the case 4 even after the case 4 is assembled to the cap 1. The number of notches 4f can be changed as desired. An O-ring 70 is housed in an annular groove 4g provided on the outer periphery of the cylindrical portion 4c of the case 4.

[0054] The solenoid valve V configured as described above is assembled to the housing 38b as follows: First, the solenoid S is inserted into the cap 1 from the bottom side of the frame 60 with the push rod 65 facing outward. At this time, the cable 66 is pulled out from the hole 60a while the solenoid S is housed in the cap 1.

[0055] Next, the valve seat member 2 is inserted into the case 4, and the coil spring 5 is inserted into the inner periphery of the valve seat member 2 at the back side of the case 4. Then, the valve body 3 is inserted into the valve seat member 2 from the cylindrical portion side, and the valve seat member 2, coil spring 5, and valve body 3 are accommodated in the case 4.

[0056] Then, the case 4 containing the valve seat member 2, the coil spring 5 and the valve body 3 is inserted from the cylindrical portion 4c side into the cylindrical portion 1b of the cap 1 containing the solenoid S until the annular protrusion 4e passes over the annular groove 1b3 provided on the inner circumference of the cylindrical portion 1b and enters the cap 1.

[0057] After the case 4 is inserted into the cap 1, a retaining ring 6 is inserted into the gap between the cylindrical portion 1b of the cap 1 and the cylindrical portion 4c of the case 4, and the retaining ring 6 is pushed into the cap 1 while reducing its diameter, inserting the retaining ring 6 into the annular groove 1b3. Then, the retaining ring 6 inserted into the annular groove 1b3 expands in diameter due to its own restoring force and becomes fixed within the annular groove 1b3. Once the retaining ring 6 is fixed to the cap 1, the case 4 is temporarily fixed to the cap 1, and can move slightly up and down relative to the cap 1 while accommodating the valve seat member 2, valve disc 3, and coil spring 5 therein, without affecting the radial alignment of the valve seat member 2 by the solenoid S.

[0058] Furthermore, when the case 4 is temporarily fastened to the cap 1, the solenoid S, valve seat member 2, valve body 3, and coil spring 5, which are components that make up the solenoid valve V, are housed inside the cap 1 and case 4 and integrated without coming apart, so that all of the components that make up the solenoid valve V can be assembled together.

[0059] When the assembled solenoid valve V is inserted into the valve hole 38b1 of the housing 38b, the case 4 fits into the small diameter portion 38b3 of the valve hole 38b1. Then, when the threaded portion 1b1 on the outer periphery of the cylindrical portion 1b of the cap 1 is screwed into the threaded groove on the inner periphery of the large diameter portion 38b2 of the valve hole 38b1, the bottom 4a of the case 4 eventually comes into contact with the bottom 38b4 of the valve hole 38b1.

[0060] Because the case 4 and cap 1 can move relative to each other in the axial direction and the case 4 abuts against the bottom 38b4 of the valve hole 38b1, further screwing in of the cap 1 moves the cap 1 toward the bottom 38b4 of the valve hole 38b1, and the cap 1, solenoid S, valve seat member 2, and case 4 are sandwiched between the cap 1 and the bottom 38b4 of the housing 38b and fixed to the housing 38b. The axial force acting on the solenoid S, valve seat member 2, and case 4 can be adjusted according to the tightening torque of the cap 1 relative to the housing 38b, making the assembly of the solenoid valve V easier than with conventional solenoid valves that have screw connections in two places.

[0061] When the solenoid valve V is assembled to the housing 38b in this manner, the hole 4b in the bottom 4a of the case 4 faces the passage 38c1 opening to the bottom 38b4, and the interior of the valve element 3 housed in the case 4 is in communication with the compression-side chamber R2 in the cylinder 31 through the passage 38c1. The axial length of the cylindrical portion 4c of the case 4 is longer than the axial length of the small-diameter portion 38b3 of the valve hole 38b1, and the case 4 protrudes from the small-diameter portion 38b3 into the large-diameter portion 38b2. Even when the case 4 is inserted into the cap 1, the case 4 has a notch 4f that opens from the flange 4d and leads inward, and the annular gap between the case 4 and the outer periphery of the valve seat member 2, facing the port 2a, is in communication with the passage 38c2 opening to the large-diameter portion 38b2 of the valve hole 38b1 via the notch 4f. As described above, the passage 38c2 is in communication with the expansion-side chamber R1 via the hole 37b of the outer tube 37, the annular gap between the cylinder 31 and the outer tube 37, and the hole 31a of the cylinder 31.

[0062] Therefore, when the port 2a of the valve seat member 2 and the port 3b of the valve body 3 face each other, the expansion-side chamber R1 and the compression-side chamber R2 are connected through the inside of the case 4, bypassing the expansion-side damping passage 33a and the compression-side damping passage 33b, and when the port 2a of the valve seat member 2 and the outer periphery of the valve body 3 face each other, the connection between the expansion-side chamber R1 and the compression-side chamber R2 through the inside of the case 4 is cut off.

[0063] In this way, the solenoid valve V is provided in the bypass passage that bypasses the extension-side damping passage 33a and the compression-side damping passage 33b, and opens the bypass passage when the port 3b of the valve element 3 is opposed to the port 2a of the valve seat member 2, and closes the bypass passage when the outer periphery of the valve element 3 closes the port 2a of the valve seat member 2. Therefore, in the solenoid valve V, in a non-energized state where no current is supplied to the coil 61 of the solenoid S, the valve element 3 is biased by the coil spring 5 to abut against the second fixed iron core 63, causing its outer periphery to face the port 2a of the valve seat member 2, thereby closing the bypass passage. When current is supplied to the coil 61 and the thrust of the solenoid S moves the valve element 3 toward the bottom 4a of the case 4 against the biasing force of the coil spring 5, the port 3b faces the port 2a, and the bypass passage is opened. Furthermore, since the amount of movement of the valve element 3 toward the bottom 4a is proportional to the magnitude of the thrust applied to the valve element 3 by the solenoid S, the degree to which the ports 2a and 3b oppose each other, i.e., the degree to which the solenoid valve V is open, can be adjusted by adjusting the amount of current supplied to the coil 61.

[0064] When the case 4 is housed in the valve hole 38b1, the O-ring 70 provided on the outer periphery of the case 4 comes into close contact with the wall surface forming the small diameter portion 38b3 of the valve hole 38b1, so the expansion-side chamber R1 and the compression-side chamber R2 are not communicated with each other through the gap between the case 4 and the small diameter portion 38b3, bypassing the solenoid valve V. Furthermore, the O-ring 50 attached to the outer periphery of the cylindrical portion 1b of the cap 1 comes into close contact with the inner periphery of the opening side without the thread grooves of the large diameter portion 38b2, so liquid does not leak from between the cap 1 and the housing 38b. The O-ring 70 provided on the outer periphery of the case 4 may be omitted if sealing is achieved by the abutment of the bottom 4a of the case 4, the housing 38a, and the bottom 38b4 of the valve hole 83b1.

[0065] The shock absorber D using the solenoid valve V configured as described above operates as follows: During the extension stroke of the shock absorber D, in which the piston 33 moves downward in FIG. 1 relative to the cylinder 31, if the solenoid valve V is closed, the liquid in the extension-side chamber R1 compressed by the piston 33 moves to the compression-side chamber R2 via the extension-side damping passage 33a. During this extension stroke, when the solenoid valve V is closed, the shock absorber D applies resistance to the flow of liquid via the extension-side damping valve 34, increasing the pressure in the extension-side chamber R1 and generating an extension-side damping force that hinders extension.

[0066] Furthermore, during the extension stroke of the shock absorber D, the piston rod 32 retracts from the cylinder 31, resulting in a shortage of liquid in the compression side chamber R2 by the volume of the piston rod 32 retracted from the cylinder 31. However, this shortage of liquid is supplied to the compression side chamber R2 from the liquid chamber L in the tank 36 by opening the suction check valve 49.

[0067] When the solenoid valve V is opened, the fluid moves from the extension-side chamber R1 to the compression-side chamber R2 through the solenoid valve V as well as the extension-side damping valve 34, so that the damping force during the extension operation of the shock absorber D can be adjusted according to the degree of opening of the solenoid valve V.

[0068] 1 relative to the cylinder 31, the liquid in the compression-side chamber R2 compressed by the piston 33 opens the compression-side damping valve 35 and moves to the extension-side chamber R1 via the compression-side damping passage 33b. Also, during the compression stroke of the shock absorber D, the piston rod 32 enters the cylinder 31, and therefore, an excess of hydraulic oil is generated in the cylinder 31 by the volume of the piston rod 32 entering the cylinder 31. This excess liquid moves from the compression-side chamber R2 to the extension-side chamber R1 via the compression-side main damping valve 48.

[0069] In this way, during the contraction stroke, when the solenoid valve V is closed, the shock absorber D applies flow resistance to the liquid through the compression side damping valve 35 and the compression side main damping valve 48, thereby increasing the pressure in the compression side chamber R2 and generating a compression side damping force that prevents contraction.

[0070] When the solenoid valve V is opened, the fluid moves from the compression side chamber R2 to the extension side chamber R1 through the solenoid valve V as well as the compression side damping valve 35, so that the damping force during the contraction operation of the shock absorber D can be adjusted according to the degree of opening of the solenoid valve V.

[0071] As described above, the solenoid valve V comprises: a housing 38b having a valve hole 38b1 that opens from one end; a cylindrical cap 1 with a bottom that is attached to the opening of the valve hole 38b1; a solenoid S housed within the cap 1; a valve seat member 2 that has a port 2a and is housed within the valve hole 38b1 and is centered radially of the solenoid S by the solenoid S; and a valve disc 3 that can open and close the port 2a in the valve seat member 2 and is driven by the solenoid S. The solenoid S and the valve seat member 2 are clamped between the cap 1 and the bottom 38b4 of the valve hole 38b1 of the housing 38b, and are fixed to the housing 38b.

[0072] In the solenoid valve V configured in this manner, by attaching the cap 1 to the housing 38b, the solenoid S and the valve seat member 2 can be clamped and fixed between the cap 1 and the bottom 38b4 of the valve hole 38b1 in the housing 38b, and the valve seat member 2 is aligned with the solenoid S. This makes it possible to fix the valve seat member 2 to the cap 1 and align the valve seat member 2 with the solenoid S without using multiple screw connections, and the solenoid valve V can be fixed to the housing 38b without using multiple screw connections as in conventional solenoid valves.

[0073] Thus, with the solenoid valve V of this embodiment, the solenoid valve V can be fixed to the housing 38b without using screw connections in multiple locations, which makes the assembly of the solenoid valve V easier. Furthermore, if screw connections are used, they are required in only one location between the cap 1 and the housing 38b, which reduces the possibility of loosening, and allows for a smaller size compared to conventional solenoid valves.

[0074] In addition, the solenoid valve V of this embodiment is equipped with a cylindrical case 4 with a bottom that houses the valve seat member 2 and the valve body 3 inside, and a retaining ring (temporary fastening member) 6 that temporarily fastens the case 4 in a state where axial movement is permitted relative to the cap 1, and the solenoid S and the valve seat member 2 are sandwiched between the bottom 38b4 of the valve hole 38b1 of the housing 38b and the cap 1 via the case 4.

[0075] In the solenoid valve V configured in this manner, the case 4 is temporarily attached to the cap 1, and the solenoid S, valve seat member 2, and valve body 3 are housed in the cap 1 and case 4 to form an assembly, which improves the ease of assembling the solenoid valve V to the housing 38b and makes assembly even easier.Since the case 4 is allowed to move axially relative to the cap 1, when the cap 1 is fixed to the housing 38b, an axial force can be applied to the solenoid S, valve seat member 2, and case 4 to fix them in place.

[0076] 1 and 2 includes a case 4, and the solenoid valve V is assembled by temporarily fastening the case 4 to the cap 1, but it is also possible to eliminate the case 4 and not assemble the solenoid valve V, but instead align the valve seat member 2 radially with the solenoid S, and clamp the solenoid S and the valve seat member 2 housing the valve disc 3 between the cap 1 and the bottom 38b4 of the valve hole 38b1 by attaching the cap 1 to the housing 38b. If it is desired to assemble the solenoid valve V1 without the case 4, a flange 2b that fits loosely onto the inner periphery of the cap 1 may be provided on the outer periphery of the valve seat member 2, as shown in FIG. 3, and the valve seat member 2 may be temporarily fastened with a retaining ring 6 to prevent the valve seat member 2 from falling off the cap 1. In this case, when the valve element 3 is biased by the coil spring 5, an annular spring bearing 2c for supporting one end of the coil spring 5 may be provided on the inner periphery of the anti-solenoid end of the valve seat member 2.

[0077] In addition, in this embodiment, the valve seat member 2 and valve disc 3 in the solenoid valve V are both cylindrical and configured as a spool valve that moves relative to one another in the axial direction to open and close the port 2a, but the valve seat member 2 does not have to be cylindrical and the valve disc 3 may be a valve disc other than a spool as long as the valve seat member 2 is aligned radially by the solenoid S. Therefore, for example, if the valve seat member 2 has a port at its bottom, the valve disc 3 may be configured as a poppet that is driven axially relative to the valve seat member 2 by the solenoid S to open and close the port, and the valve seat member 2 and valve disc 3 together form a poppet valve. In addition, in this embodiment, the coil spring 5 is provided, but if the valve disc 3 is connected to the push rod 65 of the solenoid S and the solenoid S itself has a spring that returns the movable iron core 64 to its de-energized position, the coil spring 5 in the valve seat member 2 may be eliminated. Furthermore, in this case, when the case 4 is eliminated and the valve seat member 2 is temporarily fixed to the cap 1, the valve body 3 is connected to the push rod 65 and will not fall out from within the valve seat member 2, so the valve seat member 2 can be made simply cylindrical and there is no need to provide a flange on the inner circumference of the anti-solenoid end to prevent the valve body 3 from falling out.

[0078] Furthermore, in the solenoid valve V of this embodiment, the temporary fastening member is a retaining ring 6 fixed to the inner periphery of the cap 1. In the solenoid valve V configured in this manner, the use of the retaining ring 6, which can be easily attached to the inner periphery of the cap 1, makes assembly of the solenoid valve V even easier, and the temporary fastening by the retaining ring 6 prevents the case 4 from falling off the cap 1 even if a force is applied to pull the case 4 out of the cap 1, and because the retaining ring 6 only restricts the case 4 from falling off the cap 1, it does not interfere with the movement of the case 4 in the direction of inserting it deeper into the cap 1, so the case 4 and the retaining ring 6 do not provide resistance when attaching the cap 1 to the housing 38b.

[0079] In the present invention, temporarily fastening the case 4 to the cap 1 means that the inserted state of the case 4 can be maintained in the cap 1 while allowing axial movement of the case 4, and the temporary fastening member is not limited to the retaining ring 6, but may be, for example, a rubber ring that is provided on one of the inner periphery of the cap 1 and the outer periphery of the case 4 and that is in close contact with the other of the inner periphery of the cap 1 and the outer periphery of the case 4. Furthermore, when the case 4 is inserted into the cap 1, friction generated between the cap 1 and the case 4 prevents the case 4 from falling out of the cap 1, but the case 4 may also be temporarily fastened by fitting so that the case 4 can move axially relative to the cap 1 when a force greater than the frictional force acts on the cap 1, in which case the temporary fastening member would be the case 4 itself.

[0080] Furthermore, a manufacturing method of a solenoid valve V in this embodiment is a manufacturing method of a solenoid valve V comprising: a bottomed, cylindrical cap 1 that is attached to the opening of valve hole 38b1 of housing 38b, which has valve hole 38b1 opening from one end side; a solenoid S that is housed in cap 1; a valve seat member 2 that has port 2a and is housed in valve hole 38b1 and is aligned radially of the solenoid S by the solenoid S; a valve element 3 that is capable of opening and closing port 2a in the valve seat member 2 and is driven by solenoid S; and a bottomed, cylindrical case 4 that houses the valve seat member 2 and the valve element 3 inside, and includes the steps of: accommodating the solenoid S in cap 1; accommodating the valve seat member 2 and the valve element 3 in case 4; inserting the case 4 into cap 1 and temporarily fixing the case 4 to cap 1; and inserting the cap 1, with the case 4 temporarily fixed, into valve hole 38b1 to join cap 1 to housing 38b.

[0081] According to the manufacturing method of the solenoid valve V configured in this manner, the solenoid valve V can be manufactured simply by providing a screw connection between the cap 1 and the housing 38b, which reduces the possibility of loosening, makes assembly easy, and enables miniaturization.In addition, by temporarily fastening the case 4 to the cap 1, the various parts of the solenoid valve V can be assembled together, making the assembly work of the solenoid valve V easier.

[0082] Furthermore, in the case of the solenoid valve V1 that does not have a case 4, the process of accommodating the valve seat member 2 and valve element 3 in the case 4 can be eliminated, and instead of the process of temporarily fastening the case 4 to the cap 1, a process of temporarily fastening the valve seat member 2 accommodating the valve element 3 to the cap 1 can be provided. According to the manufacturing method of the solenoid valve V1 configured in this manner, the solenoid valve V can be manufactured simply by providing a screw connection between the cap 1 and the housing 38b, which reduces the possibility of loosening, simplifies assembly, and enables miniaturization. In addition, by temporarily fastening the valve seat member 2 to the cap 1, the various components of the solenoid valve V1 can be assembled together, making the assembly of the solenoid valve V1 easier.

[0083] Although the preferred embodiment of the present invention has been described in detail, modifications, variations and changes can be made thereto without departing from the scope of the appended claims.

[0084] 1: Cap, 2: Valve seat member, 2a: Port, 3: Valve body, 4: Case, 6: Retaining ring (temporary fastening member), 38b: Housing, 38b1: Valve hole, 38b4: Bottom, S: Solenoid, V: Solenoid valve

Claims

1. A solenoid valve comprising: a bottomed cylindrical cap attached to the opening of a valve hole of a housing having a valve hole opening from one end; a solenoid contained within the cap; a valve seat member having a port and contained within the valve hole and aligned radially of the solenoid by the solenoid; and a valve body capable of opening and closing the port in the valve seat member and driven by the solenoid, wherein the solenoid and the valve seat member are clamped between the bottom of the valve hole of the housing and the cap and fixed to the housing.

2. A solenoid valve as claimed in claim 1, comprising a temporary fixing member that temporarily fixes the valve seat member in a state in which axial movement of the valve seat member is permitted relative to the cap.

3. A solenoid valve as claimed in claim 1, comprising: a cylindrical case with a bottom that houses the valve seat member and the valve body therein; and a temporary fixing member that temporarily fixes the case in a state in which axial movement is permitted relative to the cap, and the solenoid and valve seat member are sandwiched between the bottom of the valve hole of the housing and the cap via the case.

4. A solenoid valve as claimed in claim 2 or 3, wherein the temporary fastening member is a retaining ring fixed to the inner circumference of the cap.

5. A method for manufacturing a solenoid valve comprising: a cylindrical cap with a bottom that is attached to an opening of a valve hole of a housing having a valve hole that opens from one end; a solenoid contained in the cap; a valve seat member having a port that is contained in the valve hole and is aligned radially of the solenoid by the solenoid; a valve body that is capable of opening and closing the port in the valve seat member and is driven by the solenoid; and a cylindrical case with a bottom that contains the valve seat member and the valve body inside, the method comprising the steps of: accommodating the solenoid in the cap; accommodating the valve seat member and the valve body in the case; inserting the case into the cap and temporarily fixing the case to the cap; and inserting the cap with the case temporarily fixed into the valve hole and joining the cap to the housing.

6. A method for manufacturing a solenoid valve comprising: a bottomed, cylindrical cap attached to an opening of a valve hole of a housing having a valve hole opening from one end; a solenoid contained in the cap; a bottomed, cylindrical valve seat member having a port and contained in the valve hole and centered radially of the solenoid by the solenoid; and a valve body capable of opening and closing the port in the valve seat member and driven by the solenoid, the method comprising the steps of: accommodating the solenoid in the cap; accommodating the valve body in the valve seat member; inserting the valve seat member into the cap and temporarily fixing the valve seat member to the cap; and inserting the cap with the valve seat member temporarily fixed into the valve hole and joining the cap to the housing.

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