Solenoid, damping force adjustment mechanism and damping force adjustable shock absorber

Abstract

This solenoid comprises a coil, a housing, an armature, an anchor, and a cover member. The coil is wound annularly and generates a magnetic force when energized. The armature is provided movably in a winding axis direction of the coil. The anchor is provided on one side in an armature movement direction. The housing has an opening on one end side thereof in the axial direction. The cover member covers the coil and constitutes a magnetic circuit. The cover member is formed by pressing a sheet member having a uniform thickness. The cover member is formed of a plurality of members (first member and second member) having different shapes.

Description

[Technical Field]

[0001] The present disclosure relates to, for example, a solenoid, a damping force adjustment mechanism, and a damping force adjustable shock absorber. [Background technology]

[0002] Vehicles such as four-wheeled automobiles are provided with shock absorbers (dampers) between the vehicle body (sprung part) and each wheel (unsprung part). One known shock absorber for such vehicles is a damping force adjustable hydraulic shock absorber that variably adjusts the damping force according to the driving conditions, vehicle behavior, etc. The damping force adjustable hydraulic shock absorber constitutes a semi-active suspension for the vehicle.

[0003] A damping force adjustable hydraulic shock absorber variably adjusts the generated damping force by, for example, adjusting the valve opening pressure of a damping force adjustment valve using a damping force adjustable actuator. For example, a solenoid is used as the damping force adjustable actuator. For example, Patent Document 1 describes a solenoid valve in which a magnetic flux transfer member is interposed between a yoke and a stator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-117585 Summary of the Invention [Problem to be solved by the invention]

[0005] The cover member, which forms part of the solenoid's magnetic circuit and serves as a lid for the solenoid's internal components, including the coil, must be designed to avoid magnetic saturation in order to shorten the shaft length and ensure thrust. As a result, the cover member has a complex shape with thickened sections. If the cover member is formed by cutting to achieve this shape, a large amount of material must be removed from the raw material, resulting in low yield and high material costs. This also reduces productivity. Furthermore, if a pure iron-based soft magnetic material with excellent soft magnetic properties is used as the cover member, it is a soft metal and therefore difficult to cut.

[0006] An object of one embodiment of the present invention is to provide a solenoid, a damping force adjustment mechanism, and a damping force adjustable shock absorber that can ensure both performance and improve productivity. [Means for solving the problem]

[0007] One embodiment of the present invention is a solenoid, a damping force adjustment mechanism, or a damping force adjustable shock absorber, comprising: a coil wound in a ring shape and generating a magnetic force when energized; a mover made of a magnetic body and provided so as to be movable in the winding axis direction of the coil; a stator provided on one side of the mover in the moving direction; a housing member in which the mover is housed and which is open at one end side in the axial direction; and a cover member which constitutes a magnetic circuit and covers the coil. Preparation , the cover member , board It is formed by pressing a shaped member. The cover member has a cylindrical portion provided between the coil and the storage member, the outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted into the cylindrical portion, and a sealing member is provided between the step portion between the small diameter portion and the large diameter portion and the cylindrical portion.

[0008] Also, one embodiment of the present invention is a solenoid, a damping force adjustment mechanism, or a damping force adjustable shock absorber, comprising: a coil wound in a ring shape and generating a magnetic force when current is applied; a mover made of a magnetic body and provided so as to be movable in the winding axis direction of the coil; a stator provided on one side in the moving direction of the mover; a housing member in which the mover is housed and which is open at one end side in the axial direction; and a cover member which constitutes a magnetic circuit and covers the coil. Preparation The cover member is formed of a plurality of members having different shapes. The cover member has a cylindrical portion provided between the coil and the storage member, the outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted into the cylindrical portion, and a seal member is provided between a step portion between the small diameter portion and the large diameter portion and the cylindrical portion. do.

[0009] According to one embodiment of the present invention, it is possible to ensure performance and improve productivity at the same time. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a longitudinal cross-sectional view showing a damping force adjustable shock absorber incorporating a solenoid and a damping force adjustment mechanism according to an embodiment. [Figure 2] 2 is an enlarged cross-sectional view showing the damping force adjusting mechanism and the solenoid in FIG. 1. FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing the solenoid in FIG. 1. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing a solenoid according to a first modified example taken at a position similar to that of FIG. 3. [Figure 5] FIG. 4 is an enlarged cross-sectional view showing a solenoid according to a second modified example taken at a position similar to that of FIG. 3. [Figure 6] FIG. 4 is an enlarged cross-sectional view showing a solenoid according to a third modified example taken at a position similar to that of FIG. 3. [Figure 7] FIG. 5 is an enlarged cross-sectional view showing a solenoid according to a fourth modified example, taken in the same position as in FIG. 3. [Figure 8] FIG. 10 is an enlarged cross-sectional view showing a solenoid according to a fifth modified example taken at a position similar to that of FIG. 3. [Figure 9] FIG. 10 is an enlarged cross-sectional view showing a solenoid according to a sixth modified example taken at a position similar to that of FIG. 3. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing a solenoid according to a seventh modified example taken at the same position as in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the solenoid, damping force adjustment mechanism, and damping force adjustable shock absorber according to the embodiment will be described with reference to the accompanying drawings, taking as an example a case where they are used in a damping force adjustable hydraulic shock absorber incorporated in a vehicle such as a four-wheeled automobile.

[0012] 1 to 3 show an embodiment. In Fig. 1, a damping force adjustable hydraulic shock absorber 1 (hereinafter referred to as shock absorber 1) is provided with a damping force adjustment mechanism 17 that uses a solenoid 33 as a drive source. That is, shock absorber 1 as a damping force adjustable shock absorber is configured to include an outer cylinder 2 and an inner cylinder 4 as cylinders, a piston 5, a piston rod 8, and the damping force adjustment mechanism 17.

[0013] The shock absorber 1, which is a hydraulic shock absorber, has a cylindrical outer cylinder 2 with a bottom that forms an outer shell. The lower end of the outer cylinder 2 is closed by a bottom cap 3 using welding or the like. The upper end of the outer cylinder 2 forms a crimped portion 2A that is bent radially inward. A rod guide 9 and a seal member 10 are provided between the crimped portion 2A and the inner cylinder 4. Meanwhile, an opening 2B is formed at the lower side of the outer cylinder 2, concentric with a connection port 12C of the intermediate cylinder 12. A damping force adjustment mechanism 17 is attached to the lower side of the outer cylinder 2, facing the opening 2B. The bottom cap 3 is provided with a mounting eye 3A that is attached, for example, to the wheel side of a vehicle.

[0014] An inner cylinder 4 is provided coaxially with the outer cylinder 2 within the outer cylinder 2. The lower end of the inner cylinder 4 is fitted into and attached to a bottom valve 13. The upper end of the inner cylinder 4 is fitted into and attached to a rod guide 9. Oil as a working fluid is sealed within the outer cylinder 2 and inner cylinder 4 as cylinders. The working fluid is not limited to oil, and may be, for example, water mixed with an additive.

[0015] An annular reservoir chamber A is formed between the inner cylinder 4 and the outer cylinder 2. Gas is sealed in the reservoir chamber A along with oil. This gas may be air at atmospheric pressure, or a gas such as compressed nitrogen gas may also be used. The reservoir chamber A compensates for the advancement and retreat of the piston rod 8. An oil hole 4A is drilled radially at a position midway along the length (axial direction) of the inner cylinder 4, which constantly connects the rod-side oil chamber B with the annular oil chamber D.

[0016] The piston 5 is slidably provided within the inner cylinder 4. The piston 5 is inserted into the inner cylinder 4, and divides (partitions) the interior of the inner cylinder 4 into two chambers: a rod-side oil chamber B (rod-side chamber) and a bottom-side oil chamber C (bottom-side chamber). The piston 5 is formed with a plurality of oil passages 5A, 5B spaced apart in the circumferential direction, which allow communication between the rod-side oil chamber B and the bottom-side oil chamber C.

[0017] Here, an extension-side disc valve 6 is provided on the lower end surface of the piston 5. The extension-side disc valve 6 opens when the pressure in the rod-side oil chamber B exceeds a set relief pressure as the piston 5 slides upward during the extension stroke of the piston rod 8, and relieves the pressure at this time to the bottom-side oil chamber C via each oil passage 5A. The set relief pressure is set to a pressure higher than the valve-opening pressure when the damping force adjusting mechanism 17 is set to hard.

[0018] A compression-side check valve 7 is provided on the upper end surface of the piston 5. The check valve 7 opens when the piston 5 slides downward during the compression stroke of the piston rod 8 and closes at other times. The check valve 7 allows oil in the bottom-side oil chamber C to flow through each oil passage 5B toward the rod-side oil chamber B and prevents oil from flowing in the opposite direction. The opening pressure of the check valve 7 is set lower than the opening pressure when the damping force adjustment mechanism 17 is set to soft, so that it generates virtually no damping force. This means that the force is below the friction of the piston 5 and seal member 10 and does not affect the movement of the vehicle.

[0019] The piston rod 8 extends axially (vertically in FIG. 1 ) within the inner cylinder 4. The lower end of the piston rod 8 is inserted into the inner cylinder 4. The piston rod 8 is fixed to the piston 5 with a nut 8A or the like. The upper end of the piston rod 8 protrudes outside the outer cylinder 2 and the inner cylinder 4 via a rod guide 9. That is, the piston rod 8 has a lower side (lower end) which is one side (one end) connected to the piston 5, and an upper side (upper end) which is the other side (other end) extending outside the inner cylinder 4 and the outer cylinder 2. The lower end of the piston rod 8 may be further extended to protrude outward from the bottom portion (for example, the bottom cap 3) side, forming a so-called double rod.

[0020] A stepped cylindrical rod guide 9 is provided at the upper end of the inner cylinder 4. The rod guide 9 positions the upper part of the inner cylinder 4 at the center of the outer cylinder 2 and guides the piston rod 8 axially slidably on its inner periphery. An annular seal member 10 is provided between the rod guide 9 and the crimped portion 2A of the outer cylinder 2. The seal member 10 is formed, for example, by baking an elastic material such as rubber onto a metal circular plate having a hole in the center through which the piston rod 8 is inserted. The inner periphery of the elastic material of the seal member 10 slides against the outer periphery of the piston rod 8, thereby providing a seal between the piston rod 8 and the rod guide 9.

[0021] The seal member 10 has a lip seal 10A formed on its underside as a check valve that extends so as to come into contact with the rod guide 9. The lip seal 10A is disposed between the oil sump chamber 11 and the reservoir chamber A. The lip seal 10A allows oil and liquid in the oil sump chamber 11 to flow toward the reservoir chamber A through the return passage 9A of the rod guide 9, and prevents reverse flow.

[0022] An intermediate cylinder 12 made of a cylindrical body is disposed between the outer cylinder 2 and the inner cylinder 4. The intermediate cylinder 12 is attached, for example, to the outer periphery of the inner cylinder 4 via upper and lower cylindrical seals 12A and 12B. The intermediate cylinder 12 defines an annular oil chamber D therein that extends to completely surround the outer periphery of the inner cylinder 4. The annular oil chamber D is an oil chamber independent of the reservoir chamber A. The annular oil chamber D is constantly in communication with the rod-side oil chamber B via a radial oil hole 4A formed in the inner cylinder 4. The annular oil chamber D forms part of a flow path through which a flow of hydraulic fluid occurs as the piston rod 8 moves. A connection port 12C is provided at the lower end of the intermediate cylinder 12 to which a connection pipe 20 of a damping force control valve 18 is attached.

[0023] The bottom valve 13 is located at the lower end of the inner cylinder 4 and is provided between the bottom cap 3 and the inner cylinder 4. The bottom valve 13 is composed of a valve body 14 that separates (divides) the reservoir chamber A and the bottom-side oil chamber C between the bottom cap 3 and the inner cylinder 4, a contraction-side disc valve 15 provided on the underside of the valve body 14, and an extension-side check valve 16 provided on the upper side of the valve body 14. The valve body 14 has oil passages 14A and 14B formed at intervals in the circumferential direction, which allow communication between the reservoir chamber A and the bottom-side oil chamber C.

[0024] The compression-side disc valve 15 opens when the pressure in the bottom-side oil chamber C exceeds a set relief pressure as the piston 5 slides downward during the compression stroke of the piston rod 8, and relieves the pressure at this time via each oil passage 14A to the reservoir chamber A. The set relief pressure is set to a pressure higher than the valve-opening pressure when the damping force adjusting mechanism 17 is set to hard.

[0025] The extension-side check valve 16 opens when the piston 5 slides upward during the extension stroke of the piston rod 8, and closes at other times. The check valve 16 allows oil in the reservoir chamber A to flow through each oil passage 14B toward the bottom-side oil chamber C, and prevents oil from flowing in the opposite direction. The opening pressure of the check valve 16 is set to a pressure lower than the opening pressure when the damping force adjustment mechanism 17 is set to soft, and therefore generates virtually no damping force.

[0026] Next, the damping force adjusting mechanism 17 for variably adjusting the damping force generated by the shock absorber 1 will be described with reference to FIG. 2 in addition to FIG.

[0027] The damping force adjustment mechanism 17 generates a damping force by controlling the flow of hydraulic fluid (oil) generated by the sliding of the piston 5 inside the cylinder (inner tube 4), and variably adjusts the damping force generated by the shock absorber 1. Note that the damping force adjustment mechanism 17 in Fig. 2 is shown in a state in which the armature 48, operating pin 49, and pilot valve element 32 have moved to the left in Fig. 2 by externally energizing the coil 34A of the solenoid 33 (for example, control to generate a hard damping force). In other words, the damping force adjustment mechanism 17 in Fig. 2 shows a closed valve state in which the pilot valve element 32 is seated on the valve seat portion 26E of the pilot body 26.

[0028] As shown in Fig. 1, the damping force adjustment mechanism 17 is disposed such that its base end (the left end in Fig. 1) is interposed between the reservoir chamber A and the annular oil chamber D, and its tip end (the right end in Fig. 1) protrudes radially outward from the lower part of the outer cylinder 2. The damping force adjustment mechanism 17 generates a damping force by controlling the flow of oil from the annular oil chamber D to the reservoir chamber A using a damping force adjustment valve 18 (main valve 23, pilot valve body 32). The valve opening pressure of the damping force adjustment valve 18 (main valve 23, pilot valve body 32) is adjusted by a solenoid 33 used as a damping force variable actuator, thereby variably adjusting the generated damping force.

[0029] In this way, the damping force adjustment mechanism 17 generates a damping force by controlling the flow of working fluid (oil) caused by the sliding of the piston 5 inside the inner cylinder 4. To this end, the damping force adjustment mechanism 17 is configured to include a damping force adjustment valve 18 and a solenoid 33. The damping force adjustment valve 18 variably controls the flow of oil from the annular oil chamber D to the reservoir chamber A, thereby generating a damping force with hard or soft characteristics. The damping force adjustment valve 18 is driven by the solenoid 33.

[0030] That is, the damping force control valve 18 is a valve whose opening and closing operation is adjusted by the solenoid 33, and is provided in a flow path (for example, between the annular oil chamber D and the reservoir chamber A) where a flow of working fluid occurs due to the movement (extension and contraction) of the piston rod 8. The solenoid 33 adjusts the opening and closing operation of the damping force control valve 18 (pilot valve element 32, and therefore the main valve 23). In this case, the valve opening pressure of the damping force control valve 18 (pilot valve element 32, and therefore the main valve 23) is adjusted by the solenoid 33 used as a damping force variable actuator, and the generated damping force is thereby variably controlled to have hard or soft characteristics.

[0031] Here, the damping force control valve 18 is configured to include a valve case 19, a connecting pipe body 20, and a valve member 21. The valve case 19 is formed in a substantially cylindrical shape, with its base end fixed to the periphery of the opening 2B of the outer cylinder 2 and its tip end protruding radially outward from the outer cylinder 2. The connecting pipe body 20 has its base end fixed to the connection port 12C of the intermediate cylinder 12 and its tip end forming an annular flange portion 20A that is disposed inside the valve case 19 with a gap. The valve member 21 abuts against the flange portion 20A of the connecting pipe body 20.

[0032] As shown in Fig. 2, the base end side of the valve case 19 forms an annular inner flange portion 19A extending radially inward. The tip end side of the valve case 19 forms an externally threaded portion 19B onto which a lock nut 55 is threaded, connecting the valve case 19 to the yoke 39 (one side cylindrical portion 39G) of the solenoid 33. An annular oil chamber 19C that is constantly in communication with the reservoir chamber A is formed between the inner circumferential surface of the valve case 19 and the outer circumferential surface of the valve member 21, and further between the inner circumferential surface of the valve case 19 and the outer circumferential surfaces of the pilot body 26, etc. Note that instead of connecting the valve case 19 and the solenoid 33 with the lock nut 55, for example, the tip end of the valve case may be crimped to the yoke of the solenoid (a configuration without using a lock nut).

[0033] The inside of the connecting pipe body 20 has an oil passage 20B, one side of which is connected to the annular oil chamber D and the other side of which extends to the position of the valve member 21. An annular spacer 22 is sandwiched between the flange portion 20A of the connecting pipe body 20 and the inner flange portion 19A of the valve case 19. The spacer 22 has a plurality of radially extending notches 22A that serve as radial oil passages for communicating between the oil chamber 19C and the reservoir chamber A. In this embodiment, the spacer 22 is configured to have the notches 22A for forming the oil passages. However, instead of the spacer 22, notches (grooves) for forming the oil passages may be radially provided in the inner flange portion 19A of the valve case 19.

[0034] The valve member 21 is provided with a central hole 21A located at the radial center and extending in the axial direction. The valve member 21 also has a plurality of oil passages 21B spaced apart circumferentially around the central hole 21A. One side (the left side in FIGS. 1 and 2) of each oil passage 21B is constantly connected to an oil passage 20B of the connecting pipe body 20. The other end face (the right side in FIGS. 1 and 2) of the valve member 21 is provided with an annular recess 21C formed to surround the other opening of the oil passage 21B, and an annular valve seat 21D located radially outward of the annular recess 21C and on which the main valve 23 is seated and released. Each oil passage 21B of the valve member 21 serves as a flow path through which pressurized oil flows at a flow rate corresponding to the aperture of the main valve 23 between the oil passage 20B of the connecting pipe body 20, which is connected to the annular oil chamber D, and the oil chamber 19C of the valve case 19, which is connected to the reservoir chamber A.

[0035] The main valve 23 is configured as a disc valve. The inner peripheral side of the main valve 23 is sandwiched between the valve member 21 and the large diameter portion 24A of the pilot pin 24. The outer peripheral side of the main valve 23 is seated and released from the annular valve seat 21D of the valve member 21. An elastic seal member 23A is fixed to the outer peripheral portion of the back side of the main valve 23 by means of baking or the like. The main valve 23 opens when it receives pressure from the oil passage 21B side (annular oil chamber D side) of the valve member 21 and releases itself from the annular valve seat 21D. As a result, the oil passage 21B (annular oil chamber D side) of the valve member 21 is connected to the oil chamber 19C (reservoir chamber A side) via the main valve 23. The amount (flow rate) of pressurized oil flowing in the direction of arrow Y at this time is variably adjusted according to the opening of the main valve 23.

[0036] The pilot pin 24 is formed in a stepped cylindrical shape and has an annular large-diameter portion 24A provided in the axially intermediate portion. The pilot pin 24 has a central hole 24B extending axially on its inner circumferential side. A small-diameter hole (orifice 24C) is formed in one end (the end on the connecting pipe body 20 side) of the central hole 24B. One end (the left end in Figures 1 and 2) of the pilot pin 24 is press-fitted into the central hole 21A of the valve member 21. In this state, the large-diameter portion 24A of the pilot pin 24 clamps the main valve 23 between itself and the valve member 21.

[0037] The other end side (the right end side in FIGS. 1 and 2) of the pilot pin 24 is fitted into a central hole 26C of the pilot body 26. An oil passage 25 extending in the axial direction is formed between the central hole 26C of the pilot body 26 and the other end side of the pilot pin 24. This oil passage 25 communicates with a back pressure chamber 27 formed between the main valve 23 and the pilot body 26. In other words, a plurality of oil passages 25 extending in the axial direction are provided in the circumferential direction on the side surface of the other end side of the pilot pin 24, and other circumferential positions are press-fitted into the central hole 26C of the pilot body 26.

[0038] The pilot body 26 is formed as a generally bottomed cylindrical body and includes a cylindrical portion 26A with a stepped hole formed on the inside and a bottom portion 26B that closes the cylindrical portion 26A. The bottom portion 26B of the pilot body 26 has a central hole 26C into which the other end of the pilot pin 24 fits. A protruding cylindrical portion 26D is integrally formed on one end (the left end in FIGS. 1 and 2 ) of the bottom portion 26B of the pilot body 26, located on the outer diameter side and protruding along its entire circumference toward the valve member 21. The elastic seal member 23A of the main valve 23 is fluid-tightly fitted to the inner circumferential surface of the protruding cylindrical portion 26D, thereby forming a backpressure chamber 27 between the main valve 23 and the pilot body 26. The backpressure chamber 27 generates pressure (internal pressure, pilot pressure) that presses the main valve 23 in a valve-closing direction, i.e., in a direction that seats the main valve 23 against the annular valve seat 21D of the valve member 21.

[0039] A valve seat 26E on which the pilot valve element 32 seats and disengages is provided so as to surround the central hole 26C at the other end side (the right end side in FIGS. 1 and 2) of the bottom 26B of the pilot body 26. Inside the cylindrical portion 26A of the pilot body 26, there are disposed a return spring 28 that urges the pilot valve element 32 in a direction away from the valve seat 26E of the pilot body 26, a disk valve 29 that constitutes a fail-safe valve when the solenoid 33 is in a de-energized state (when the pilot valve element 32 is farthest from the valve seat 26E), a retaining plate 30 in which an oil passage 30A is formed on the central side, and the like.

[0040] A cap 31 is fitted and fixed to the open end of the cylindrical portion 26A of the pilot body 26, with the return spring 28, disc valve 29, retaining plate 30, etc., arranged inside the cylindrical portion 26A. Notches 31A are formed in the cap 31, for example, at four positions spaced apart in the circumferential direction. As shown by arrows X in Figure 2, the notches 31A serve as flow paths that allow oil that has flowed through the oil passage 30A of the retaining plate 30 to the solenoid 33 side to circulate to the oil chamber 19C (reservoir chamber A side).

[0041] The pilot valve element 32, together with the pilot body 26, constitutes a pilot valve (control valve). The pilot valve element 32 is formed in a stepped cylindrical shape. The tip of the pilot valve element 32, i.e., the tip that seats on and separates from the valve seat 26E of the pilot body 26, is tapered. An operating pin 49 of the solenoid 33 is fitted and fixed inside the pilot valve element 32, and the valve opening pressure of the pilot valve element 32, and therefore the valve opening pressure of the main valve 23, is adjusted in accordance with the supply of electricity to the solenoid 33.

[0042] That is, the pilot valve (pilot body 26 and pilot valve element 32) serving as a control valve is controlled by the axial movement of an operating pin 49 of the solenoid 33 (more specifically, an armature 48 fixed to the operating pin 49). A flange portion 32A serving as a spring bearing is formed around the entire circumference on the base end side of the pilot valve element 32. When the solenoid 33 is not energized, that is, when the pilot valve element 32 is displaced to the fully open position where it is farthest from the valve seat 26E, the flange portion 32A comes into contact with the inner periphery of the disc valve 29, thereby constituting a fail-safe valve.

[0043] Next, the solenoid 33, which constitutes the damping force adjusting mechanism 17 together with the damping force adjusting valve 18, will be described with reference to Fig. 3 in addition to Figs. 1 and 2. Note that in Fig. 3, reference numerals are assigned with the right side of the left-right direction in Fig. 2 facing upward. That is, the left-right direction in Figs. 1 and 2 corresponds to the up-down direction in Fig. 3.

[0044] The solenoid 33 is incorporated into the damping force adjustment mechanism 17 as a variable damping force actuator of the damping force adjustment mechanism 17. That is, the solenoid 33 is used in a damping force adjustable shock absorber to adjust the opening and closing operation of the damping force adjustment valve 18. The solenoid 33 includes a molded coil 34, a housing 36 as a storage member (magnetic member), a yoke 39 as a case member, an anchor 41 as a stator (fixed iron core), a cylinder 44 as a joining member (non-magnetic ring), an armature 48 as a mover (movable iron core), an operating pin 49 as a shaft portion, and a cover member 51.

[0045] The molded coil 34 is formed into a substantially cylindrical shape by winding a coil 34A around a coil bobbin 34B and integrally covering (molding) the coil 34A with a resin member 34C such as a thermosetting resin. A cable outlet (not shown) that protrudes axially or radially outward is provided at a portion of the circumference of the molded coil 34, and an electric cable (not shown) is connected to this cable outlet. The coil 34A of the molded coil 34 is wound in a circular shape around the coil bobbin 34B, and becomes an electromagnet to generate a magnetic field (magnetic force) when power is supplied (energized) from an external cable.

[0046] A seal groove 34D is formed around the entire circumference of the resin member 34C of the molded coil 34 on the side (one axial end face) facing the yoke 39 (annular portion 39B). A seal member (e.g., O-ring 35) is fitted in the seal groove 34D. The O-ring 35 provides a liquid-tight seal between the molded coil 34 and the yoke 39 (annular portion 39B). This prevents dust, including rainwater and muddy water, from entering the cylindrical protrusion 39C side of the yoke 39 through the gap between the yoke 39 and the molded coil 34.

[0047] The coil used in this embodiment is not limited to the molded coil 34 made up of the coil 34A, the coil bobbin 34B, and the resin member 34C, and other coils may also be used. For example, the coil may be wound around a coil bobbin made of an electrically insulating material, and the outer periphery of the coil may be covered with an overmold (not shown) made of a resin material molded from above (the outer periphery side).

[0048] The housing 36 constitutes a storage member (magnetic member) disposed on the inner periphery of the molded coil 34 (i.e., the inner periphery of the coil 34A). The housing 36 is formed as a covered cylindrical body using a magnetic material (magnetic substance) such as low-carbon steel or carbon steel for mechanical structures (S10C). The housing 36 includes a cylindrical storage portion 36A serving as a storage portion, a lid portion 36B, and a small-diameter cylindrical portion 36C. The cylindrical storage portion 36A extends in the direction of the winding axis of the molded coil 34 (coil 34A) and is open at one end (left side in FIG. 2, bottom side in FIG. 3). The lid portion 36B closes the other end (right side in FIG. 2, top side in FIG. 3) of the cylindrical storage portion 36A. The small-diameter cylindrical portion 36C is located on the open side (one side) of the cylindrical storage portion 36A and is formed to reduce the outer diameter of the cylindrical storage portion 36A.

[0049] The inner periphery of the cylinder 44 is joined to the outer periphery of the small diameter cylindrical portion 36C of the housing 36 by brazing. The inner diameter of the cylindrical storage portion 36A of the housing 36 is formed to be slightly larger than the outer diameter of the armature 48. The armature 48 is housed within the cylindrical storage portion 36A so that it can move axially. That is, one end of the housing 36 in the axial direction is open, and the armature 48 is housed therein. The housing 36 and the cylinder 44 form a pressure vessel by press-fitting the housing 36 (small diameter cylindrical portion 36C) into the inside of the cylinder 44 and brazing them together.

[0050] Meanwhile, the lid portion 36B of the housing 36 is formed integrally with the cylindrical storage portion 36A as a covered cylinder that closes the other axial side of the cylindrical storage portion 36A. The lid portion 36B has a stepped shape with an outer diameter smaller than that of the cylindrical storage portion 36A. A cylindrical portion 51A of a cover member 51 is fitted to the outer periphery of the lid portion 36B. The housing 36 also has a bottomed stepped hole 37 formed inside the lid portion 36B. The stepped hole 37 has a bushing mounting hole portion 37A and a small-diameter hole portion 37B located deeper than the bushing mounting hole portion 37A and formed with a smaller diameter. A first bushing 38 is provided in the bushing mounting hole portion 37A as a bearing (first bearing) for slidably supporting the actuation pin 49.

[0051] The lid portion 36B of the housing 36 is disposed so that its other end surface faces the lid portion 51B of the cover member 51, with an axial gap therebetween. This axial gap serves to prevent axial force from being directly applied to the housing 36 from the lid portion 51B side of the cover member 51 via the lid portion 36B. The lid portion 36B of the housing 36 does not necessarily have to be formed integrally with the cylindrical storage portion 36A using the same material (magnetic material). In this case, the lid portion 36B can be formed not only from a magnetic material but also from a rigid metal material, ceramic material, or fiber-reinforced resin material, for example. The joint between the cylindrical storage portion 36A and the lid portion 36B of the housing 36 is positioned in consideration of the transfer of magnetic flux.

[0052] The yoke 39 is provided on one side of the armature 48 in the direction of movement. The yoke 39 is a magnetic member that, together with the housing 36, forms a magnetic circuit (magnetic path) between the inner and outer peripheries of the molded coil 34 (coil 34A). That is, the yoke 39 is formed of the same magnetic material as the housing 36. The yoke 39 includes an annular portion 39B that extends radially from one axial side (one side in the winding axis direction) of the molded coil 34 (coil 34A) and has a stepped fixing hole 39A on its inner periphery, and a cylindrical protrusion 39C that protrudes cylindrically from the inner periphery of the annular portion 39B toward the other axial side (the coil 34A side) along the axial direction of the fixing hole 39A. The cylindrical protrusion 39C forms a protrusion (cylindrical portion) for joining with the cylinder 44, and the cylinder 44 is inserted into the inner diameter side of the cylindrical protrusion 39C.

[0053] In other words, yoke 39 has a fixing hole 39A, and anchor 41 is disposed within fixing hole 39A. An inward flange 39D that protrudes radially inward along the entire circumference is provided within fixing hole 39A. One axial end face (one end face) of cylinder 44 abuts against the side face (the side face on the coil 34A side) of inward flange 39D. The outer periphery of one axial end of cylinder 44 is fitted into the inner periphery of yoke 39, i.e., the inner surface of fixing hole 39A (in other words, the inner circumferential surface of cylindrical protrusion 39C).

[0054] The yoke 39 is formed as a single unit including a cylindrical one-side tube portion 39G extending from the outer periphery of the annular portion 39B toward one axial side (the main valve 23 side), an other-side tube portion 39H extending from the outer periphery of the annular portion 39B toward the other axial side (the cover member 51 side) and formed to surround the molded coil 34 from the radial outside, and a crimped portion 39J provided at the tip of the other-side tube portion 39H and holding the flange 51C of the cover member 51 in a non-removable state. The other-side tube portion 39H of the yoke 39 is provided with a notch (not shown) for exposing the cable outlet portion of the molded coil 34 to the outside of the other-side tube portion 39H.

[0055] Between one side cylindrical portion 39G and the other side cylindrical portion 39H of the yoke 39, engagement recesses 39L having a semicircular cross section are provided (along the entire circumference or at multiple locations spaced apart in the circumferential direction) so as to open onto the outer circumferential surface of the yoke 39. A lock nut 55 threadedly attached to the valve case 19 is engaged with the engagement recesses 39L via a retaining ring 56 (see FIG. 2). Furthermore, a seal groove 39M is provided along the entire circumference on the outer circumferential surface of the one side cylindrical portion 39G. An O-ring 40 (see FIG. 2) serving as a seal member is fitted into the seal groove 39M. The O-ring 40 provides a liquid-tight seal between the yoke 39 (one side cylindrical portion 39G) and the valve case 19 of the damping force control valve 18.

[0056] The anchor 41 is provided on one side of the armature 48 in the direction of movement. The anchor 41 is disposed axially opposite the armature 48. The anchor 41 is a stator (fixed core) fixed in the fixing hole 39A of the yoke 39 by press-fitting or other means. The anchor 41, like the housing 36 and the yoke 39, is made of a magnetic material (magnetic substance) such as low-carbon steel or carbon steel for mechanical structures (S10C) and is shaped to fill the fixing hole 39A of the yoke 39 from the inside. The anchor 41 is formed as a short cylindrical annular body with a through-hole 41A extending axially at its center. One axial side surface of the anchor 41 (the surface axially facing the cap 31 shown in FIG. 2 ) is formed to be flat, similar to one side surface of the annular portion 39B of the yoke 39.

[0057] A circular recessed portion 41B is recessed on the other axial side of the anchor 41 (the other side axially facing the armature 48) so as to be coaxial with the cylindrical storage portion 36A of the housing 36. The recessed portion 41B is formed as a circular groove with a diameter slightly larger than that of the armature 48 so that the armature 48 can be inserted therein and withdrawn by magnetic force. For this purpose, a cylindrical outer peripheral protrusion 41C is provided on the other side of the anchor 41. The outer peripheral surface on the opening side of the outer peripheral protrusion 41C is formed as a conical surface so that the magnetic characteristics between the anchor 41 and the armature 48 are linear. In other words, the outer peripheral protrusion 41C, also called a corner portion, protrudes cylindrically from the outer peripheral side of the anchor 41 toward the other axial side. The outer peripheral surface (the outer peripheral surface on the opening side) of the outer peripheral protrusion 41C is a tapered conical surface so that the outer diameter gradually decreases toward the other axial side (the opening side).

[0058] Additionally, a side surface portion 41D is formed on the outer periphery of the anchor 41, extending in a direction away from the opening of the cylindrical storage portion 36A of the housing 36 along the outer periphery of the outer periphery protrusion 41C. The end of this side surface portion 41D away from the opening forms an annular flange portion 41E that protrudes radially outward. The annular flange portion 41E is located at a position significantly spaced apart from the open end of the cylindrical storage portion 36A of the housing 36 to one side in the axial direction (i.e., the end opposite the recessed portion 41B).

[0059] The annular flange portion 41E is fixed, for example, by press-fitting or other means into the fixing hole 39A of the yoke 39. The annular flange portion 41E serves as a fixing portion for the anchor 41 (side surface portion 41D) to the fixing hole 39A of the yoke 39, and is also the portion where the flange portion 41E and the fixing hole 39A face each other in the radial direction. The side surface 41D of the anchor 41 (excluding the annular flange portion 41E) faces the inner circumferential surface of the cylinder 44 and the inner surface of the inward flange portion 39D of the yoke 39 via a gap (radial gap).

[0060] As shown in Fig. 3, a second bushing 43 serving as a bearing (second bearing) for slidably supporting an operating pin 49 is fitted into a stepped through hole 41A formed on the center (inner periphery) side of the anchor 41. Meanwhile, as shown in Fig. 2, the pilot body 26, return spring 28, disc valve 29, retaining plate 30, cap 31, etc. are inserted into the inner periphery side of one side cylindrical portion 39G of the yoke 39. In addition, the valve case 19 is fitted (externally fitted) onto the outer periphery side of the one side cylindrical portion 39G.

[0061] The cylinder 44 is disposed between the yoke 39 and the anchor 41 in the radial direction. The cylinder 44 is also disposed between the yoke 39 and the housing 36 in the axial and radial directions. That is, the cylinder 44 is a non-magnetic connecting member (joint member) located between the small-diameter cylindrical portion 36C of the housing 36 and the cylindrical protrusion portion 39C of the yoke 39 and disposed on the inner periphery of the molded coil 34 (coil 34A). The cylinder 44 is made of a non-magnetic material. More specifically, the cylinder 44 is formed as a cylindrical body (simple cylindrical body) from a non-magnetic material such as austenitic stainless steel.

[0062] The outer periphery of the cylinder 44 at one end (yoke 39 side) in the winding axis direction of the molded coil 34 (coil 34A) is joined to the inner periphery of the yoke 39 (fixing hole 39A, cylindrical protrusion 39C). As a result, one axial side of the cylinder 44 is fixed to the yoke 39, which serves as the stator. Also, the inner periphery of the cylinder 44 at the other end (housing 36 side) in the winding axis direction of the molded coil 34 (coil 34A) is joined to the outer periphery of the housing 36 (small diameter cylindrical portion 36C). That is, the cylinder 44 is fitted (press-fitted) onto the outside (outer periphery side) of the small diameter cylindrical portion 36C of the housing 36, and the two are joined by brazing.

[0063] The armature 48, also called a plunger, is disposed between the cylindrical storage portion 36A of the housing 36 and the recessed portion 41B of the anchor 41. The armature 48 is a moving element (movable iron core) made of a magnetic material that is movable in the winding axis direction of the coil 34A. That is, the armature 48 is disposed on the inner periphery of the coil 34A so as to be movable in the axial direction. The armature 48 is disposed on the inner periphery of the cylindrical storage portion 36A of the housing 36, the recessed portion 41B of the anchor 41, the cylindrical protrusion portion 39C of the yoke 39, and the cylinder 44, and is movable in the axial direction between the cylindrical storage portion 36A of the housing 36 and the recessed portion 41B of the anchor 41. That is, the armature 48 is disposed on the inner periphery of the cylindrical storage portion 36A of the housing 36 and the recessed portion 41B of the anchor 41, and is movable in the axial direction via the first and second bushings 38 and 43 and the actuation pin 49 by the magnetic force generated in the coil 34A.

[0064] The armature 48 is fixed (integrated) to (is integral with) the actuation pin 49 that extends through the center of the armature 48, and moves together with the actuation pin 49. The actuation pin 49 is supported by the cover portion 36B of the housing 36 and the anchor 41 via the first and second bushings 38, 43 so as to be slidable in the axial direction. Here, the armature 48 is formed in a substantially cylindrical shape using an iron-based magnetic material, for example, like the housing 36, the yoke 39, and the anchor 41. A magnetic force generated in the coil 34A generates a thrust (attraction force) in the armature 48 that attracts the armature 48 toward the recessed portion 41B of the anchor 41.

[0065] The actuating pin 49 is a shaft portion that transmits the thrust of the armature 48 to the pilot valve element 32, and is formed from a hollow rod. The actuating pin 49 displaces integrally with the armature 48. That is, the armature 48 is fixed integrally to the axial middle portion of the actuating pin 49 by means of press fitting or the like, thereby forming the armature 48 and actuating pin 49 into a sub-assembly. Both axial ends of the actuating pin 49 are slidably supported by the cover portion 36B on the housing 36 side and the yoke 39 (anchor 41) via first and second bushings 38, 43.

[0066] One end of the operating pin 49 (the left end in FIG. 2 and the lower end in FIG. 3) protrudes in the axial direction from the anchor 41 (yoke 39), and the pilot valve element 32 of the damping force control valve 18 is fixed to the protruding end. Therefore, the pilot valve element 32 moves integrally in the axial direction together with the armature 48 and the operating pin 49. In other words, the set valve opening pressure of the pilot valve element 32 becomes a pressure value corresponding to the thrust of the armature 48 based on the energization of the coil 34A. The armature 48 moves in the axial direction due to the magnetic force from the coil 34A, thereby opening and closing the pilot valve of the shock absorber 1 (i.e., the pilot valve element 32 relative to the pilot body 26).

[0067] The cover member 51 is a magnetic cover that covers the molded coil 34 from the outside together with the other-side cylindrical portion 39H of the yoke 39. The cover member 51 is formed of a magnetic material (magnetic substance) as a lid that covers the molded coil 34 from the other axial side, and forms a magnetic circuit (magnetic path) outside the molded coil 34 (coil 34A) together with the other-side cylindrical portion 39H of the yoke 39. The cover member 51 is formed in a lidded cylindrical shape as a whole. That is, the cover member 51 has a cylindrical portion 51A through which the lid portion 36B of the housing 36 is inserted, a disk-shaped lid portion 51B that closes the other end side of the cylindrical portion 51A (the right end portion in FIG. 2, the upper end portion in FIG. 3), and an annular (ring-shaped) flange portion 51C that extends from the lid portion 51B radially outward beyond the cylindrical portion 51A.

[0068] In this embodiment, the cover member 51 includes a disk-shaped first member 52 and a second member 53 having a cylindrical portion 53A and an annular portion 53B. The first member 52 of the cover member 51 corresponds to the lid portion 51B and the flange portion 51C of the cover member 51, the cylindrical portion 53A of the second member 53 corresponds to the cylindrical portion 51A, and the flange portion 53B of the second member 53 corresponds to the flange portion 51C.

[0069] The flange portion 51C of the cover member 51 is fixed to a crimped portion 39J provided on the other-side cylindrical portion 39H of the yoke 39. As a result, the other-side cylindrical portion 39H of the yoke 39 and the lid portion 51B of the cover member 51 are pre-assembled (sub-assembled) with the molded coil 34 housed inside, as shown in FIG. 3. In this manner, with the molded coil 34 housed inside the other-side cylindrical portion 39H of the yoke 39 and the lid portion 51B of the cover member 51, the lid portion 36B of the housing 36 is fitted into the cylindrical portion 51A of the cover member 51. As a result, magnetic flux can be transferred between the cylindrical portion 51A of the cover member 51, the lid portion 51B, and the yoke 39.

[0070] A seal member (e.g., an O-ring 54) is fitted in the space surrounded by one end (left end in FIG. 2, bottom end in FIG. 3) of the cylindrical portion 51A of the cover member 51, the outer periphery of the lid portion 36B of the housing 36, and the inner periphery of the resin member 34C of the molded coil 34. The O-ring 54 provides a liquid-tight seal between the molded coil 34 (resin member 34C), the cover member 51 (cylindrical portion 51A), and the housing 36 (lid portion 36B). This prevents dust containing rainwater or muddy water from entering the interior through the gap between the cover member 51 and the molded coil 34. The cover member 51 will be described in detail later.

[0071] The yoke 39 and cover member 51, with the molded coil 34 housed inside as shown in Fig. 3, are fastened to the valve case 19 of the damping force control valve 18 using a lock nut 55 and a retaining ring 56 as fastening members as shown in Fig. 2. In this case, the retaining ring 56 is attached to the engagement recess 39L of the yoke 39 prior to the lock nut 55. The retaining ring 56 partially protrudes radially outward from the engagement recess 39L of the yoke 39 and transmits the fastening force of the lock nut 55 to one side cylindrical portion 39G of the yoke 39.

[0072] The lock nut 55 is formed as a stepped cylindrical body and is provided with: a female threaded portion 55A located on one axial side thereof and threadedly engaging with the male threaded portion 19B of the valve case 19 on its inner peripheral side; and an engaging cylindrical portion 55B bent radially inward so that its inner diameter is smaller than the outer diameter of the retaining ring 56 and engaging with the retaining ring 56 from the outside. The lock nut 55 is a fastening member that integrally connects the damping force control valve 18 and the solenoid 33 by threading the female threaded portion 55A into the male threaded portion 19B of the valve case 19 with the inner surface of the engaging cylindrical portion 55B abutting against the retaining ring 56 attached to the engaging recess 39L of the yoke 39.

[0073] The cover member (lid member), which constitutes part of the solenoid's magnetic circuit and serves as a lid for the solenoid's internal components, including the coil, must be designed to avoid magnetic saturation in order to achieve both a short shaft length and sufficient thrust. As a result, the cover member has a complex shape with thicker sections. For example, the cover member may have a shape that combines a disk-shaped section and a cylindrical section. If the cover member is machined to achieve such a shape, the amount of material removed from the raw material increases, resulting in poor yield and high material costs. This also reduces productivity. Furthermore, if a pure iron-based soft magnetic material with excellent soft magnetic properties is used as the cover member, it is a soft metal and therefore difficult to machine.

[0074] Therefore, in the embodiment, the cover member 51 is formed by pressing a plate-shaped member (plate-shaped material) of uniform thickness. Also, in the embodiment, the cover member 51 is formed of a plurality of members (first member 52, second member 53) of different shapes. This ensures the thrust of the armature 48, which serves as the mover, improves (improves) the yield of the cover member 51, improves productivity, reduces costs, and reduces the number of management items from materials to completion. These points will be explained in detail below.

[0075] 1, the shock absorber 1 includes an inner cylinder 4 and an outer cylinder 2 as cylinders, a piston 5, a piston rod 8, an annular oil chamber D serving as a flow path (more specifically, a flow path between the annular oil chamber D and the reservoir chamber A), and a damping force control valve 18 (a pilot valve element 32, and therefore a main valve 23). The damping force control valve 18 (the pilot valve element 32, and therefore the main valve 23) is provided in the flow path where the flow of working fluid occurs due to the extension and contraction of the piston rod 8, i.e., between the annular oil chamber D and the reservoir chamber A. The damping force control valve 18 (the pilot valve element 32, and therefore the main valve 23) is driven by a solenoid 33.

[0076] 2, the damping force adjustment mechanism 17 has a coil 34A, an armature 48 as a mover, an anchor 41 as a stator, a housing 36 as a storage member, a cover member 51, and a damping force adjustment valve 18 as a control valve (more specifically, a pilot valve element 32, and therefore the main valve 23). The damping force adjustment valve 18 (pilot valve element 32, and therefore the main valve 23) is controlled by axial movement of the armature 48 fixed to an operating pin 49. Also, as shown in FIG. 3, the solenoid 33 has a coil 34A, an armature 48 as a mover, the anchor 41 as a stator, a housing 36 as a storage member, and a cover member 51.

[0077] The coil 34A is wound in a circular shape and generates a magnetic force when current is applied. The armature 48 is made of a magnetic material. The armature 48 is provided so as to be movable in the winding axis direction of the coil 34A. The anchor 41 is provided on one side of the armature 48 in the movement direction (the lower side in the vertical direction in Figure 3). The housing 36 accommodates the armature 48. The housing 36 is provided radially between the coil 34A and the armature 48. The housing 36 is open at one end side in the axial direction of the coil 34A (the lower side in the vertical direction in Figure 3). The cover member 51 covers the coil 34A. The cover member 51 constitutes a magnetic circuit.

[0078] As shown in FIG. 3 , the cover member 51 is formed by pressing a plate-like member of uniform thickness. Specifically, the cover member 51 is composed of a first member 52 and a second member 53, each of which is formed by pressing a plate-like material of uniform thickness, made of, for example, metal. As a result, the cover member 51 is formed by the first member 52 and the second member 53, which are multiple members of different shapes. Specifically, the cover member 51 includes the first member 52, which is a disk-shaped member, and the second member 53, which has an L-shaped cross section. The first member 52 and the second member 53 are separate components. Pressing is a processing method in which, for example, a metal or non-metallic material is cut or formed into a desired shape and dimensions by applying force using two or more pairs of tools (e.g., a die, an upper die, a lower die, a male die, and a female die). Examples of press processing include shearing, drawing, bending, forging, stretch forming, rotational forming, and hydroforming.

[0079] The first member 52 and the second member 53 may be formed as an inseparable integral part, for example, by bonding, or may be separate, separable parts without bonding. The second member 53 has a cylindrical portion 53A and a flange-shaped annular portion 53B extending radially outward from the opening edge of one end side (the first member 52 side) of the cylindrical portion 53A. The cylindrical portion 53A of the second member 53 is fitted into the lid portion 36B of the housing 36. That is, the cover member 51 has a cylindrical portion 51A (cylindrical portion 53A) provided between the coil 34A and the housing 36. Meanwhile, the outer diameter of the housing 36 has the lid portion 36B, which is a small-diameter portion, and the storage cylindrical portion 36A, which is a large-diameter portion. The cylindrical portion 51A of the cover member 51, i.e., the cylindrical portion 53A of the second member 53, is press-fitted into the lid portion 36B.

[0080] In this case, the lid portion 36B and the cylindrical storage portion 36A of the housing 36 are connected by a step portion 36D. An O-ring 54 serving as a sealing member is provided between the step portion 36D of the housing 36 and the cylindrical portion 51A of the cover member 51. In the embodiment, the second member 53 of the cover member 51 is integrally formed with a cylindrical portion 53A that forms the cylindrical portion 51A of the cover member 51 and an annular portion 53B that forms the portion other than the cylindrical portion 51A. Meanwhile, the cylindrical portion 53A (cylindrical portion 51A) of the second member 53 is formed separately from the first member 52 that forms the portion other than the cylindrical portion 51A. That is, the cylindrical portion 51A of the cover member 51 (cylindrical portion 53A of the second member 53) is formed integrally with the annular portion 53B of the second member 53 and is formed separately from the first member 52.

[0081] The outer periphery of the coil 34A is covered by the other-side cylindrical portion 39H of the yoke 39, which serves as a case member. That is, the solenoid 33 includes the yoke 39, more specifically, the other-side cylindrical portion 39H, which covers the outer periphery of the coil 34A. The other-side cylindrical portion 39H has a large-diameter portion 39H1 and a small-diameter portion 39H2 connected to the large-diameter portion 39H1 formed at one end of its inner periphery. The cover member 51 is placed on a step portion 39H3 formed by the large-diameter portion 39H1 and the small-diameter portion 39H2. The cover member 51 is then fixed to the other-side cylindrical portion 39H by crimping the large-diameter portion 39H1 to the cover member 51 (the flange portion 51C). Furthermore, in this embodiment, the cover member 51 covers the other axial end (the lid portion 36B) of the housing 36.

[0082] In this case, a gap is formed between the first member 52 of the cover member 51 and the other axial end surface of the housing 36 (the end surface of the lid portion 36B). In contrast, the annular portion 53B of the second member 53 contacts the first member 52. That is, the annular portions 53B of the first member 52 and the second member 53 contact each other with the large-diameter portion 39H1 of the other-side tubular portion 39H crimped to the cover member 51 (the flange portion 51C). Furthermore, with the large-diameter portion 39H1 of the other-side tubular portion 39H crimped to the cover member 51 (the flange portion 51C), the annular portion 53B of the second member 53 contacts the step portion 39H3 of the other-side tubular portion 39H. As a result, the cover member 51 forms a magnetic circuit.

[0083] In this embodiment, in order to increase the productivity of the cover member 51 that constitutes the magnetic circuit, the cover member 51 is made up of plate-like members (first member 52, second member 53) of uniform thickness. In other words, the cover member 51 is made up of a plurality of bodies (a plurality of parts), namely, the first member 52 and the second member 53. Furthermore, the cover member 51, more specifically, the first member 52 and the second member 53 that are members (parts) that constitute the cover member 51, have shapes that can be formed by pressing. This reduces the cost of the cover member 51 and improves productivity.

[0084] The solenoid 33, the damping force adjusting mechanism 17 and the shock absorber 1 according to this embodiment have the above-described configurations, and their operation will now be described.

[0085] First, when the shock absorber 1 is mounted on a vehicle such as an automobile, for example, the upper end (protruding end) of the piston rod 8 is attached to the vehicle body, and the mounting eye 3A provided on the bottom cap 3 is attached to the wheel. Also, the solenoid 33 of the damping force adjusting mechanism 17 is connected to a control device (controller) provided on the vehicle body via an electrical wiring cable (neither is shown) or the like.

[0086] When the vehicle is traveling and vertical vibrations occur due to unevenness in the road surface or the like, the piston rod 8 is displaced so as to extend or contract from the outer cylinder 2, and a damping force can be generated by the damping force adjustment mechanism 17 or the like, thereby cushioning the vehicle vibrations. At this time, the controller controls the current value to the coil 34A of the solenoid 33 to adjust the valve opening pressure of the pilot valve body 32, thereby variably adjusting the damping force generated by the shock absorber 1.

[0087] For example, during the extension stroke of the piston rod 8, the movement of the piston 5 inside the inner cylinder 4 closes the compression-side check valve 7 of the piston 5. Before the disc valve 6 of the piston 5 opens, the oil in the rod-side oil chamber B is pressurized and flows into the oil passage 20B of the connecting pipe body 20 of the damping force control valve 18 through the oil hole 4A of the inner cylinder 4, the annular oil chamber D, and the connection port 12C of the intermediate cylinder 12. At this time, the oil equivalent to the movement of the piston 5 flows from the reservoir chamber A into the bottom-side oil chamber C, opening the extension-side check valve 16 of the bottom valve 13. When the pressure in the rod-side oil chamber B reaches the opening pressure of the disc valve 6, the disc valve 6 opens, relieving the pressure in the rod-side oil chamber B to the bottom-side oil chamber C.

[0088] In the damping force adjusting mechanism 17, before the main valve 23 opens (when the piston speed is in the low speed range), the oil that has flowed into the oil passage 20B of the connecting pipe body 20 passes through the center hole 21A of the valve member 21, the center hole 24B of the pilot pin 24, and the center hole 26C of the pilot body 26, as shown by arrow X in Fig. 2, pushes open the pilot valve element 32, and flows into the inside of the pilot body 26. The oil that has flowed into the inside of the pilot body 26 then flows between the flange portion 32A of the pilot valve element 32 and the disc valve 29, through the oil passage 30A of the retaining plate 30, the notch 31A of the cap 31, and the oil chamber 19C of the valve case 19, to the reservoir chamber A. As the piston speed increases, the pressure in the oil passage 20B of the connecting pipe body 20, i.e., the pressure in the rod-side oil chamber B, reaches the valve-opening pressure of the main valve 23. As shown by arrow Y in Figure 2, the oil that has flowed into the oil passage 20B of the connecting pipe body 20 passes through the oil passage 21B of the valve member 21, pushes open the main valve 23, and flows into the reservoir chamber A through the oil chamber 19C of the valve case 19.

[0089] On the other hand, during the compression stroke of the piston rod 8, the movement of the piston 5 inside the inner cylinder 4 opens the compression-side check valve 7 of the piston 5, and the extension-side check valve 16 of the bottom valve 13 closes. Before the bottom valve 13 (disc valve 15) opens, oil in the bottom-side oil chamber C flows into the rod-side oil chamber B. At the same time, oil equivalent to the amount of oil that the piston rod 8 has penetrated into the inner cylinder 4 flows from the rod-side oil chamber B via the damping force control valve 18 to the reservoir chamber A, following the same route as during the extension stroke. When the pressure in the bottom-side oil chamber C reaches the opening pressure of the bottom valve 13 (disc valve 15), the bottom valve 13 (disc valve 15) opens, relieving the pressure in the bottom-side oil chamber C to the reservoir chamber A.

[0090] As a result, during the extension stroke and compression stroke of the piston rod 8, before the main valve 23 of the damping force control valve 18 opens, a damping force is generated by the orifice 24C of the pilot pin 24 and the valve-opening pressure of the pilot valve element 32, and after the main valve 23 opens, a damping force is generated according to the opening degree of the main valve 23. In this case, by adjusting the valve-opening pressure of the pilot valve element 32 by energizing the coil 34A of the solenoid 33, it is possible to directly control the damping force regardless of the piston speed.

[0091] Specifically, when the current flowing through the coil 34A is reduced to reduce the thrust of the armature 48, the valve-opening pressure of the pilot valve element 32 decreases, generating a soft damping force. On the other hand, when the current flowing through the coil 34A is increased to increase the thrust of the armature 48, the valve-opening pressure of the pilot valve element 32 increases, generating a hard damping force. At this time, the internal pressure of the back pressure chamber 27, which communicates with the pilot valve element 32 via the upstream oil passage 25, changes depending on the valve-opening pressure of the pilot valve element 32. As a result, by controlling the valve-opening pressure of the pilot valve element 32, the valve-opening pressure of the main valve 23 can be adjusted at the same time, thereby widening the adjustment range of the damping force characteristics.

[0092] If the thrust of the armature 48 is lost due to a break in the coil 34A or the like, the pilot valve element 32 will move backward (displaced in a direction away from the valve seat 26E) due to the return spring 28, and the flange portion 32A of the pilot valve element 32 will come into contact with the disc valve 29. In this state, a damping force can be generated by the valve-opening pressure of the disc valve 29, and the necessary damping force can be obtained even in the event of a malfunction such as a break in the coil.

[0093] According to the embodiment, the first and second members 52 and 53 constituting the cover member 51 are formed by pressing a plate-shaped member (plate-shaped material) of uniform thickness. The cover member 51 is formed from the first and second members 52 and 53, which are multiple members with different shapes. This improves productivity while maintaining flexibility in the shape of the cover member 51. Compared to a machined cover member, this method can improve yield, productivity, cost, and the number of management items from material to completion while maintaining the thrust of the armature 48. Furthermore, even when a pure iron-based soft magnetic material with excellent soft magnetic properties is used for the cover member 51, the cover member 51 can be easily formed. Therefore, even if the shape of the cover member 51 becomes complex in order to maintain the thrust of the armature 48, productivity can be maintained. Conversely, this method can ensure productivity while ensuring the area of ​​the magnetically necessary parts and suppressing a decrease in thrust (magnetic saturation). As a result, it is possible to ensure the performance of the solenoid 33, the damping force adjusting mechanism 17, and ultimately the shock absorber 1, while also improving productivity.

[0094] According to the embodiment, the cover member 51 has a cylindrical portion 51A (in other words, the cylindrical portion 53A of the second member 53) provided between the coil 34A and the housing 36. Therefore, a magnetic circuit can be formed by the cylindrical portion 51A (cylindrical portion 53A). This allows for optimization of the magnetic circuit and improvement of productivity.

[0095] According to the embodiment, the housing 36 has a lid portion 36B serving as a small-diameter portion, a cylindrical storage portion 36A serving as a large-diameter portion, and a step portion 36D between the lid portion 36B and the cylindrical storage portion 36A. Furthermore, the cylindrical portion 51A (cylindrical portion 53A) of the cover member 51 is press-fitted into the lid portion 36B. This prevents the housing 36 from rattling relative to the cover member 51. An O-ring 54 serving as a sealing member is provided between the step portion 36D of the housing 36 and the cylindrical portion 51A (cylindrical portion 53A) of the cover member 51. This allows the O-ring 54 to seal the gap between the housing 36 and the cover member 51. This prevents moisture (water) such as rainwater or muddy water from entering from the outside.

[0096] According to the embodiment, in the cover member 51, the cylindrical portion 53A of the second member 53 is formed integrally with the annular portion 53B of the second member 53, and the cylindrical portion 53A of the second member 53 is formed separately from the first member 52. This allows the cover member 51 to be configured from two parts, with the cylindrical portion 51A being a separate part.

[0097] According to the embodiment, the cover member 51 is placed on the step portion 39H3 of the other-side cylindrical portion 39H of the yoke 39, and is fixed to the yoke 39 (other-side cylindrical portion 39H) by crimping the large-diameter portion 39H1 of the other-side cylindrical portion 39H to the cover member 51. Therefore, the cover member 51 can be fixed to the yoke 39 (other-side cylindrical portion 39H) while ensuring an axial gap between the cover member 51 and the housing 36. Therefore, even if a load is applied to the cover member 51, it is possible to prevent this load from being applied to the housing 36. This makes it possible to prevent excessive force from being applied to the housing 36, thereby improving pressure resistance and impact resistance.

[0098] According to this embodiment, the cover member 51 covers the other axial end side (the end of the lid portion 36B) of the housing 36. Therefore, the cover member 51 can protect the housing 36 (the lid portion 36B).

[0099] In the embodiment, the cover member 51 is described as being made up of two members (multiple members), the first member 52 and the second member 53. However, the present invention is not limited to this, and the cover member may be made up of a single member (one member). That is, for example, as in a first modified example shown in FIG. 4, the cover member 61 may be made up of a single member having an L-shaped vertical cross section like the second member 53 (FIG. 3) of the embodiment. In this case, the cover member 61 of the first modified example is thicker than the second member 53 (FIG. 3) of the embodiment.

[0100] The cover member 61 of the first modified example has a cylindrical portion 61A and a flange-like annular portion 61B extending radially outward from the opening edge of one end of the cylindrical portion 61A (the side opposite the armature 48) all the way around. The cylindrical portion 61A corresponds to the cylindrical portion provided between the coil 34A and the housing 36. The cylindrical portion 61A is press-fitted into the lid portion 36B of the housing 36. The annular portion 61B corresponds to the annular (ring-shaped) flange extending radially outward from the cylindrical portion 61A. The cover member 61 is formed by pressing a plate-shaped member (e.g., a metal plate-shaped material) of uniform thickness. In this case, the cover member 61 is integrally formed with the cylindrical portion 61A and the annular portion 61B, which is the portion other than the cylindrical portion 61A.

[0101] Additionally, an O-ring 54 serving as a sealing member is provided between the step 36D of the housing 36 and the cylindrical portion 61A of the cover member 61. In this case, another step 36E is formed in the lid portion 36B of the housing 36, positioned closer to the cover member 61 than the step 36D. For this reason, the housing 36 is provided with an intermediate cylindrical portion 36F between the cylindrical storage portion 36A and the lid portion 36B, the intermediate cylindrical portion 36F having an outer diameter larger than that of the lid portion 36B and smaller than that of the cylindrical storage portion 36A.

[0102] The cylindrical portion 61A of the cover member 61 extends toward another step portion 36E of the housing 36. The O-ring 54 is disposed between the outer peripheral surface of the intermediate cylindrical portion 36F, the cylindrical portion 61A of the cover member 61, and the inner peripheral surface of the molded coil 34 (resin member 34C). That is, the O-ring 54 is provided between the step portion 36D and the cylindrical portion 61A of the cover member 61. Furthermore, the cover member 61 is fixed to the other cylindrical portion 39H by crimping the large diameter portion 39H1 of the yoke 39 to the cover member 61. In the first modified example, the other axial end side (lid portion 36B) of the housing 36 is inserted into the cover member 61 (cylindrical portion 61A and annular portion 61B). When the large diameter portion 39H1 of the other cylindrical portion 39H is crimped to the cover member 61, a gap is formed between one end side of the cylindrical portion 61A of the cover member 61 and another step portion 36E of the housing 36.

[0103] Like the embodiment, this first modified example also ensures the thrust of the armature 48 while improving the yield of the cover member 61, improving productivity, reducing costs, and reducing the number of management items from material selection to completion. In particular, in the first modified example, the cylindrical portion 61A (cylindrical portion) and the annular portion 61B (a portion other than the cylindrical portion) of the cover member 61 are integrally formed. This allows the cover member 61 to be configured as a single part with the cylindrical portion 61A integrated into it. Furthermore, in the first modified example, the other axial end side (lid portion 36B) of the housing 36 is inserted into the cover member 61. This allows the housing 36 (lid portion 36B) to be exposed from the cover member 61.

[0104] In the above-described embodiment, the cover member 51 is described as being composed of a disk-shaped first member 52 and a second member 53 having an L-shaped cross section. However, this is not limiting, and the cover member may be composed of a disk-shaped first member and a cylindrical second member. That is, for example, as in the second modified example shown in FIG. 5, the cover member 62 may be composed of a disk-shaped first member 63 and a cylindrical second member 64. In this case, the first member 63 of the second modified example is thicker than the first member 52 (FIG. 3) of the embodiment. In the second modified example, as in the embodiment, the first member 63 and the second member 64 are separate components. The first member 63 and the second member 64 may be integral components that are inseparable, for example, by bonding, or they may be separate components that are not bonded.

[0105] At least the first member 63 of the cover member 62 is formed by pressing a plate-like member (for example, a metal plate-like material) of uniform thickness. The second member 64 is a pipe (circular tube) and is provided between the coil 34A and the housing 36. The second member 64 corresponds to the cylindrical portion of the cover member 62. The second member 64 is press-fitted into the lid portion 36B of the housing 36. Such a second member 64 may be formed by pressing, or may be formed by a process other than pressing. In either case, the cover member 62 is formed by the first member 63 and the second member 64, which are multiple members with different shapes. In the cover member 62, the second member 64, which corresponds to the cylindrical portion, and the first member 63, which is the other portion, are formed separately.

[0106] An O-ring 54 serving as a sealing member is provided between the step portion 36D of the housing 36 and the second member 64 of the cover member 61. The cover member 62 is fixed to the other-side tubular portion 39H by crimping the large-diameter portion 39H1 of the yoke 39 to the first member 63 of the cover member 51. In the second modified example, the first member 63 of the cover member 62 covers the other axial end side (lid portion 36B) of the housing 36. In this state, a gap is formed between the first member 63 of the cover member 62 and the other axial end face of the housing 36 (end face of the lid portion 36B). Meanwhile, the second member 64 is in contact with the first member 63, and the outer diameter side of the first member 63 is in contact with the step portion 39H3 of the other-side tubular portion 39H.

[0107] Like the embodiment, this second modification also ensures the thrust of the armature 48 while improving the yield of the cover member 61, improving productivity, reducing costs, and reducing the number of management items from material selection to completion. In particular, in the second modification, the cover member 62 includes a cylindrical second member 64 that forms a cylindrical portion press-fitted into the lid portion 36B of the housing 36. Therefore, the cover member 62 can be configured as two parts: the cylindrical second member 64 and the disk-shaped first member 63. As shown in a third modification in FIG. 6 , a positioning recess 65 for positioning the second member 64 may be provided on the first member 63 at a position facing the second member 64. The positioning recess 65 is formed as an annular groove into which the end (edge) of the second member 64 fits. This third modification allows stable contact between the end (edge) of the second member 64 and the first member 63.

[0108] In the above-described embodiment, the cover member 51 is described as being composed of a "disk-shaped first member 52" and a "second member 53 having an L-shaped cross section." However, the present invention is not limited to this configuration, and the cover member may be composed of a "disk-shaped first member" and a "circular (annular) second member." That is, for example, as in a fourth modified example shown in FIG. 7, the cover member 66 may be composed of a disk-shaped first member 67 and a circular (annular) second member 68. A circular through-hole 68A is formed in the second member 68. The other axial end (lid portion 36B) of the housing 36 is fitted into the through-hole 68A.

[0109] In the fourth modified example, the first member 67 and the second member 68 of the cover member 66 are formed by pressing a plate-like member (e.g., a metal plate-like material) of uniform thickness. The cover member 66 is formed by a plurality of first and second members 67 and 68 that are different in shape. The first member 67 corresponds to the first plate-like member of uniform thickness. The second member 68 corresponds to the second plate-like member that is located closer to the coil 34A than the first member 67, overlaps the first member 67, and has a smaller area than the first member 67. The cover member 66 is fixed to the other-side cylindrical portion 39H by crimping the large-diameter portion 39H1 of the yoke 39 to the first member 67 of the cover member 66. The first member 67 of the cover member 66 covers the other axial end side (lid portion 36B) of the housing 36. In this state, a gap is formed between the first member 67 of the cover member 66 and the other axial end face (end face of the lid portion 36B) of the housing 36. Meanwhile, the first member 67 and the second member 68 are in contact with each other, and the outer diameter side of the second member 68 is in contact with the step portion 39H3 of the other-side cylindrical portion 39H.

[0110] Like the embodiment, the first, second, and third modifications, this fourth modification can improve productivity while ensuring the thrust of the armature 48. In particular, in the fourth modification, the cover member 66 includes a first plate-shaped member (first member 67) having a uniform thickness and a second plate-shaped member (second member 68) located closer to the coil 34A than the first plate-shaped member (first member 67) and having a smaller area than the first plate-shaped member (first member 67). This allows the second plate-shaped member (second member 68) to be disposed in a magnetically saturated portion. Therefore, the cover member 66 can be easily formed using the first plate-shaped member (first member 67) and the second plate-shaped member (second member 68) while ensuring the thrust of the armature 48.

[0111] In the above-described embodiment, an example was described in which the cover member 51 was fixed to the yoke 39 (other-side cylindrical portion 39H) serving as a case member by crimping the cover member 51 to the yoke 39 (other-side cylindrical portion 39H). However, this is not limiting, and the cover member may be fixed to the case member (yoke, other-side cylindrical portion) by press-fitting. That is, for example, as in a fifth modified example shown in FIG. 8 , the cover member 69 may be formed of a first member 70 and a second member 71, and the first member 70 (outer cylindrical portion 70A) may be press-fitted into the yoke 39 (other-side cylindrical portion 39H) to fix the cover member 69 to the yoke 39 (other-side cylindrical portion 39H) serving as a case member.

[0112] In the embodiment (FIG. 3), the other-side cylindrical portion 39H of the yoke 39 is formed integrally with the annular portion 39B and one-side cylindrical portion 39G of the yoke 39. In contrast, in the fifth modified example (FIG. 6), the other-side cylindrical portion 39H of the yoke 39 is formed separately from the annular portion 39B and one-side cylindrical portion 39G. That is, the other-side cylindrical portion 39H is fixed by press-fitting, adhesive, or the like to the inside (inner peripheral surface side) of a cylindrical fixed cylindrical portion 39N that extends from the annular portion 39B toward the cover member 69. In addition, the cover member 69 is fixed by press-fitting to the outside (outer peripheral surface side) of the other-side cylindrical portion 39H.

[0113] The cover member 69 includes a first member 70 having a cylindrical shape with a lid and a second member 71 having an annular (circular ring) shape. The first member 70 and the second member 71 are separate components. The first member 70 and the second member 71 may be bonded together to form an inseparable integral component, or may be separate components that are not bonded together. The first member 70 includes a cylindrical outer cylindrical portion 70A that is fixed to the other cylindrical portion 39H of the yoke 39 by press-fitting, and a disk-shaped lid portion 70B that covers an opening on one end side of the outer cylindrical portion 70A. The second member 71 is disposed inside the outer cylindrical portion 70A of the first member 70 and abuts (contacts) the lid portion 70B of the first member 70. A gap is formed between the lid portion 70B of the first member 70 and the other axial end face of the housing 36 (the end face of the lid portion 36B). The tip side (other end side) of the other cylindrical portion 39H abuts (contacts) the outer diameter side of the second member 71.

[0114] In the fifth modified example, the first member 70 and the second member 71 of the cover member 69 are also formed by pressing a plate-shaped member (e.g., a metal plate-shaped material) of uniform thickness. The cover member 69 is formed of a plurality of first members 70 and second members 71 that are different in shape. The first member 70 corresponds to the first plate-shaped member of uniform thickness. The second member 71 corresponds to the second plate-shaped member that is located closer to the coil 34A than the first member 70, overlaps the first member 70, and has a smaller area than the first member 70. The first member 70 of the cover member 69 covers the other axial end side (lid portion 36B) of the housing 36. This fifth modified example can also improve productivity while ensuring the thrust of the armature 48.

[0115] In the fifth modified example, the second member 71 of the cover member 69 is formed in an annular (ring-shaped) shape. However, this is not limiting. For example, as in a sixth modified example shown in FIG. 9, the cover member 72 may be composed of a first member 70 and a second member 73, and the second member 73 may have a cylindrical portion 73A and an annular portion 73B, like the second member 53 (FIG. 3) of the embodiment. The cylindrical portion 73A of the second member 73 corresponds to the cylindrical portion provided between the coil 34A and the housing 36. The cylindrical portion 73A of the second member 73 is press-fitted into the lid portion 36B.

[0116] In the sixth modified example, the first member 70 and the second member 73 of the cover member 72 are also formed by pressing a plate-shaped member (e.g., a metal plate-shaped material) of uniform thickness. The cover member 72 is formed by a plurality of members, the first member 70 and the second member 73, of different shapes. The first member 70 corresponds to the first plate-shaped member of uniform thickness. The second member 73 corresponds to the second plate-shaped member that is located closer to the coil 34A than the first member 70, overlaps the first member 70, and has a smaller area than the first member 70. The first member 70 of the cover member 72 covers the other axial end side (lid portion 36B) of the housing 36. The cylindrical portion 73A of the second member 73 is formed integrally with the annular portion 73B of the second member 73 and is formed separately from the first member 70. The annular portion 73B of the second member 73 is disposed inside the outer cylindrical portion 70A of the first member 70 and abuts against the lid portion 70B of the first member 70. A gap is formed between the lid portion 70B of the first member 70 and the other axial end face of the housing 36 (the end face of the lid portion 36B). In addition, the tip side (other end side) of the other-side cylindrical portion 39H abuts (contacts) against the outer diameter side of the second member 73. This sixth modified example also ensures the thrust of the armature 48 and improves productivity.

[0117] In the fifth and sixth modified examples, the cover members 69 and 72 are described as being composed of a first member 70 and second members 71 and 73. However, this is not limiting. For example, as in the seventh modified example shown in FIG. 10, the cover member 74 may be composed of a single member. Similar to the cover member 61 of the first modified example (FIG. 4), the cover member 74 of the seventh modified example includes a cylindrical portion 74A and a flange-shaped annular portion 74B extending radially outward from the opening edge of one end of the cylindrical portion 74A (the side opposite the armature 48) over the entire circumference. Additionally, the cover member 74 of the seventh modified example includes an outer cylindrical portion 74C on the outer peripheral edge side of the annular portion 74B, which is press-fitted and fixed to the other cylindrical portion 39H of the yoke 39. With the cover member 74 (outer cylindrical portion 74C) fixed by press-fitting into the other-side cylindrical portion 39H of the yoke 39, the annular portion 74B of the cover member 74 abuts (contacts) the tip side (other end side) of the other-side cylindrical portion 39H. In contrast, a gap is formed between one end side (the armature 48 side) of the cylindrical portion 74A of the cover member 74 and another step portion 36E of the housing 36. This seventh modified example also ensures the thrust of the armature 48 and improves productivity.

[0118] In the embodiment and the modified example, the housing 36 and the cylinder 44, and the cylinder 44 and the yoke 39 are joined together using brazing material. However, this is not limiting, and for example, the housing 36 and the cylinder 44, and the cylinder 44 and the yoke 39 may be joined together by welding.

[0119] In the embodiment and the modified example, the anchor 41 is fixed by press-fitting into the fixing hole 39A of the yoke 39. However, the present invention is not limited to this, and the anchor may be fixed into the yoke using, for example, a screw or other threading means, a caulking means, or the like.

[0120] In the embodiment and the modified example, the anchor 41 and the yoke 39 are configured as separate bodies (separate parts) as described above. However, the present invention is not limited to this, and the anchor and the yoke may be configured as one integral part (one part).

[0121] In the embodiment and the modified example, a case has been described in which one side of the cylinder 44 is fixed to the yoke 39. However, the present invention is not limited to this, and for example, one side of the cylinder (joint member) may be fixed to the anchor.

[0122] In the embodiment and the modified example, the solenoid 33 is configured as a proportional solenoid. However, the present invention is not limited to this, and the solenoid 33 may be configured as an ON / OFF solenoid, for example.

[0123] In the embodiment and the modified example, a twin-tube shock absorber 1 consisting of an outer tube 2 and an inner tube 4 has been described as an example. However, the present invention is not limited to this, and may be used, for example, in a damping force adjustable shock absorber consisting of a single-tube cylindrical member (cylinder).

[0124] In the embodiment and modified examples, the solenoid 33 is used as a variable damping force actuator for the shock absorber 1, that is, the pilot valve element 32 constituting the pilot valve of the damping force control valve 18 is used as the object to be driven by the solenoid 33. However, the solenoid is not limited to this, and can be widely used as, for example, an actuator incorporated into various mechanical devices such as a valve used in a hydraulic circuit, that is, a drive device that drives an object to be driven linearly.

[0125] The embodiments and modifications are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments and modifications is possible.

[0126] According to the above-described embodiment and / or modified examples (hereinafter simply referred to as "embodiments"), the cover member is formed by pressing a plate-shaped member of uniform thickness. This allows for improved productivity while maintaining flexibility in the shape of the cover member. That is, compared to a machined cover member, this allows for improved yield, improved productivity, cost reduction, and fewer management items from material to completion while maintaining the thrust of the mover. Furthermore, even when a pure iron-based soft magnetic material with excellent soft magnetic properties is used for the cover member, this allows for easy formation of the cover member. Therefore, even if the cover member has a complex shape to ensure the thrust of the mover, productivity can be maintained. Conversely, productivity can be maintained while ensuring the area of ​​the magnetically necessary parts and suppressing a decrease in thrust (magnetic saturation). As a result, it is possible to ensure the performance of the solenoid, damping force adjustment mechanism, and damping force adjustable shock absorber while also improving productivity.

[0127] According to the embodiment, the cover member is formed from multiple components with different shapes. This allows for improved productivity while maintaining flexibility in the shape of the cover member. That is, compared to machined covers, this allows for improved yield, improved productivity, cost reduction, and fewer management items from material to completion while maintaining the thrust of the mover. Furthermore, even when a pure iron-based soft magnetic material with excellent soft magnetic properties is used for the cover member, this allows for easy formation of the cover member. Therefore, even if the cover member has a complex shape to ensure the thrust of the mover, productivity can be maintained. Conversely, this allows for the area of ​​magnetically necessary parts to be secured while maintaining productivity, thereby suppressing a decrease in thrust (magnetic saturation). As a result, it is possible to simultaneously ensure the performance of the solenoid, damping force adjustment mechanism, and damping force adjustable shock absorber and improve productivity.

[0128] According to an embodiment, the cover member includes a first plate-shaped member having a uniform thickness and a second plate-shaped member that is located closer to the coil than the first plate-shaped member, overlaps the first plate-shaped member, and has a smaller area than the first plate-shaped member. This allows the second plate-shaped member to be placed in a magnetically saturated portion. Therefore, the cover member can be easily formed using the first plate-shaped member and the second plate-shaped member while ensuring the thrust of the mover.

[0129] According to the embodiment, the cover member has a cylindrical portion provided between the coil and the housing member. Therefore, the cylindrical portion can form a magnetic circuit. This allows for optimization of the magnetic circuit and improvement of productivity.

[0130] According to an embodiment, the outer diameter of the storage member has a small diameter portion, a large diameter portion, and a step portion between the small diameter portion and the large diameter portion. The cylindrical portion of the cover member is press-fitted into the small diameter portion. This prevents the storage member from rattling relative to the cover member. A seal member is also provided between the step portion of the storage member and the cylindrical portion of the cover member. This allows the seal member to seal the gap between the storage member and the cover member. This prevents moisture (water) such as rainwater or muddy water from entering from the outside.

[0131] According to the embodiment, the cover member is formed such that the cylindrical portion and the portion other than the cylindrical portion are formed integrally or separately, whereby the cover member can be configured as a single piece with the cylindrical portion being an integral part, or as two (or more) pieces with the cylindrical portion being a separate part.

[0132] According to an embodiment, the cover member is placed on a stepped portion of the case member and is fixed to the case member by crimping the large diameter portion of the case member to the cover member. Therefore, the cover member can be fixed to the case member while maintaining an axial gap between the cover member and the housing member. Therefore, even if a load is applied to the cover member, the load can be prevented from being applied to the housing member. This prevents excessive force from being applied to the housing member, improving pressure resistance and impact resistance.

[0133] According to the embodiment, the cover member covers the other axial end of the storage member or has the other axial end of the storage member inserted therethrough. Therefore, when the cover member covers the other axial end of the storage member, the cover member can protect the storage member. On the other hand, when the cover member has the other axial end of the storage member inserted therethrough, the storage member can be exposed from the cover member.

[0134] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0135] This application claims priority to Japanese Patent Application No. 2022-094354, filed June 10, 2022. The entire disclosure of Japanese Patent Application No. 2022-094354, filed June 10, 2022, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety. [Explanation of symbols]

[0136] 1: Buffer (damping force adjustable buffer) 2: Outer cylinder 4: Inner cylinder 5: Piston 8: Piston rod 17: Damping force adjustment mechanism 18: Damping force adjustment valve 32: Pilot valve body (control valve) 33: Solenoid 34A: Coil 36: Housing (storage component) 36A: Storage cylinder (large diameter part) 36B: Lid (small diameter part) 36D: Multilayered section 39: Yoke (case component) 39H: Other side tube part (case member) 39H1: Large diameter section 39H2: Small diameter part 39H3: Multilayered section 41: Anchor (stator) 48: Armature (moving element) 51, 61, 62, 66, 69, 72, 74: Cover members 51A: Cylindrical part 52, 63, 67, 70: First member 53, 64, 68, 71, 73: Second member 53A, 61A, 73A, 74A: Cylindrical part (cylindrical part) 54: O-ring (sealing material)

Claims

1. A solenoid, the solenoid comprising: A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil, The cover member is formed by pressing a plate-shaped member, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, The solenoid has a seal member provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

2. A solenoid, the solenoid comprising: A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil, The cover member is formed of a plurality of members having different shapes, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, The solenoid has a seal member provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

3. 2. The solenoid of claim 1, The plate-like member is A first plate-shaped member; a second plate-shaped member that is located closer to the coil than the first plate-shaped member and overlaps the first plate-shaped member, and that has a smaller area than the first plate-shaped member;

4. 3. The solenoid of claim 2, The plurality of members include: A first plate-shaped member; a second plate-shaped member that is located closer to the coil than the first plate-shaped member and overlaps the first plate-shaped member, and that has a smaller area than the first plate-shaped member;

5. 3. The solenoid according to claim 1 or 2, The cover member is a solenoid in which the cylindrical portion and a portion other than the cylindrical portion are formed integrally or separately.

6. 3. The solenoid according to claim 1 or 2, a case member covering an outer periphery of the coil; The case member has an inner periphery formed at one end thereof with a large diameter portion and a small diameter portion connected to the large diameter portion, the cover member is placed on a step formed by the large diameter portion and the small diameter portion, The cover member is fixed to the case member by crimping the large diameter portion to the cover member.

7. 3. The solenoid according to claim 1 or 2, The cover member covers the other axial end side of the housing member, or the other axial end side of the housing member is inserted into a solenoid.

8. A damping force adjustment mechanism, the damping force adjustment mechanism comprising: A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil; a control valve controlled by the axial movement of the movable element; The cover member is formed by pressing a plate-shaped member, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, A damping force adjusting mechanism in which a seal member is provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

9. A damping force adjustment mechanism, the damping force adjustment mechanism comprising: A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil; a control valve controlled by the axial movement of the movable element; The cover member is formed of a plurality of members having different shapes, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, A damping force adjusting mechanism in which a seal member is provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

10. A damping force adjustable shock absorber, comprising: a cylinder in which a working fluid is sealed; a piston inserted into the cylinder to divide the interior of the cylinder into a rod-side chamber and a bottom-side chamber; a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder; a flow path in which the flow of the working fluid occurs due to extension and contraction of the piston rod; a damping force adjusting valve provided in the flow path and driven by a solenoid, The solenoid is A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil, The cover member is formed by pressing a plate-shaped member, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, A damping force control shock absorber, wherein a seal member is provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

11. A damping force adjustable shock absorber, comprising: a cylinder in which a working fluid is sealed; a piston inserted into the cylinder to divide the interior of the cylinder into a rod-side chamber and a bottom-side chamber; a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder; a flow path in which the flow of the working fluid occurs due to extension and contraction of the piston rod; a damping force adjusting valve provided in the flow path and driven by a solenoid, The solenoid is A coil wound in a circular shape that generates magnetic force when current is passed through it; a mover made of a magnetic material and provided so as to be movable in the direction of the winding axis of the coil; a stator provided on one side of the moving element in the moving direction; a housing member in which the movable element is housed and which is open at one end side in the axial direction; a cover member that forms a magnetic circuit and covers the coil, The cover member is formed of a plurality of members having different shapes, the cover member has a cylindrical portion provided between the coil and the housing member, The outer diameter of the storage member has a small diameter portion and a large diameter portion, the small diameter portion is inserted through the cylindrical portion, A damping force control shock absorber, wherein a seal member is provided between the cylindrical portion and a step portion between the small diameter portion and the large diameter portion.

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