Valve drive and shock absorber using it

Abstract

The present invention provides a valve driving device capable of suppressing a size increase and improving a thrust force, and a shock absorber using the same. The present invention includes a bobbin 2 having a main body portion; a solenoid coil 1 wound around the main body portion of the bobbin 2; an armature 10 disposed on a radially inner side of the bobbin 2 and fixed to a rod 9; an anchor 8 covering one side of the armature 10 in an axial direction at a position located radially inward of the bobbin 2; a yoke 4 disposed between the bobbin 2 and the anchor 8; and a cylindrical member 6 disposed between the bobbin 2 and the armature 10. The bobbin 2 has a recess 2A formed on a radially inner side, and a portion of the cylindrical member 6 is inserted into the recess 2A. The portion of the cylindrical member 6 and the recess 2A are disposed in a radially laminated manner. The armature 10 is movable in an axial direction between a position where the portion of the cylindrical member 6 and the recess 2A are radially laminated and a position where the portion of the cylindrical member 6 and the recess 2A are not laminated.

Description

TECHNICAL FIELD

[0001] The present application relates to a valve driving device and a shock absorber using the same. BACKGROUND

[0002] As a conventional damping force adjusting type shock absorber, for example, there is the technology described in Patent Literature 1. The damping force adjusting type shock absorber described in Patent Literature 1 includes a solenoid housing that houses a damping force generating mechanism that generates a damping force and a solenoid that drives the damping force generating mechanism. The flow of working fluid caused by the movement of the piston in the cylinder is controlled by the damping force generating mechanism in the solenoid housing.

[0003] PROBLEMS IN THE PRIOR ART

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2019-27460 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The solenoid that drives the damping force generating mechanism includes a coil wound around a bobbin (also referred to as a spool or a bobbin tube), a pair of cores inserted into the coil, a plunger axially movably supported between the pair of cores, and a working rod coupled to the plunger.

[0008] In the damping force adjusting type shock absorber, an increase in thrust is required in order to expand the adjustment range of the damping force. In addition, the damping force adjusting type shock absorber is required to be downsized in order to improve mountability on a vehicle or the like.

[0009] In order to increase the thrust in the damping force adjusting type shock absorber, it is necessary to increase the diameter of the plunger. In the technology described in Patent Literature 1, in the case where the diameter of the plunger is to be increased, the inner diameter of the coil has to be increased, and along with this, the cores and the solenoid housing are also increased, and there is a technical problem that the shock absorber is upsized.

[0010] An object of the present application is to solve the above-described technical problem, and to provide a valve driving device capable of suppressing upsizing and improving thrust, and a shock absorber using the same.

[0011] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0012] To achieve the above object, the present application is a valve driving device for a damping force adjustable shock absorber, characterized by comprising: a bobbin having a cylindrical main body portion; a coil wound around the main body portion of the bobbin; an anchor fixed to a rod, which is arranged on a radially inner side of the bobbin; an anchor member arranged on a radially inner side of the bobbin compared to the bobbin, which covers one side of the anchor in an axial direction; a yoke arranged between the bobbin and the anchor member; and a cylindrical member arranged between the bobbin and the anchor, the bobbin having a recess formed on a radially inner side, a portion of the cylindrical member being inserted into the recess, the portion of the cylindrical member and the recess being arranged in a radially laminated manner, the anchor being movable in the axial direction between a position where the portion of the cylindrical member and the recess are laminated in the radial direction and a position where the portion of the cylindrical member and the recess are not laminated in the radial direction.

[0013] Effects of the Invention

[0014] According to the present application, it is possible to provide a valve driving device capable of suppressing an increase in size and improving a pushing force, and a shock absorber using the same. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a view showing a hydraulic circuit of main components in a shock absorber of the first embodiment of the present application.

[0016] Figure 2 is a sectional view of an electromagnetic solenoid of the first embodiment of the present application.

[0017] Figure 3 is a sectional view of an electromagnetic solenoid of the second embodiment of the present application.

[0018] Figure 4 is a sectional view of an electromagnetic solenoid of the third embodiment of the present application. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of a shock absorber of the present application will be described with reference to the drawings. In addition, the present application is not limited to the following embodiments, and various modifications and applications are included in the scope of the technical concept of the present application.

[0020] Embodiment 1

[0021] For the first embodiment of the present application, the following Figure 1 and Figure 2 will be described. Figure 1 is a view showing a hydraulic circuit of main components in a shock absorber of the first embodiment of the present application. Figure 1 In the following description, a damping force adjustable shock absorber will be described. Figure 1The upward direction (upper side) and the downward direction (lower side) in the figure are referred to as the upward direction (upper side) and the downward direction (lower side) of the shock absorber 61, and the upward and downward directions are illustrated in each figure. In addition, the direction in which the rod 9 extends (the upward and downward directions) is referred to as the axial direction, the direction orthogonal to the axial direction of the rod 9 is referred to as the radial direction, the direction close to the rod 9 is referred to as the radially inner side, and the direction away from the rod 9 is referred to as the radially outer side. Figure 2 is a cross-sectional view of an electromagnetic solenoid of the first embodiment of the present application.

[0022] As shown in Figure 1 , the shock absorber 61 of the first embodiment includes a cylindrical cylinder 62, a reservoir 64, and a damping force generation mechanism 85. The shock absorber 61 is installed between two members capable of moving relative to each other, such as the spring (vehicle body) side, the spring lower (wheel) side, and the like of the suspension device of an unillustrated vehicle.

[0023] A piston 65 is slidably fitted in the cylinder 62, and the cylinder 62 is partitioned by the piston 65 into an upper cylinder chamber 62A and a lower cylinder chamber 62B.

[0024] A piston rod 66 is connected to the piston 65, and the end portion of the piston rod 66 on the side opposite to the piston 65 protrudes to the outside of the cylinder 62 through the upper cylinder chamber 62A and through an unillustrated oil seal. On the lower end side of the cylinder 62, a base valve 70 that partitions the lower cylinder chamber 62B from the reservoir 64 is provided.

[0025] One (part) of the reservoir 64 is connected to the upper cylinder chamber 62A of the cylinder 62, and the other (part) of the reservoir 64 is connected to the lower cylinder chamber 62B of the cylinder 62 via the base valve 70. In addition, the damping force generation mechanism 85 is provided between the cylinder 62 and the reservoir 64. In the first embodiment, the damping force generation mechanism 85 is connected between one of the reservoir 64 and the upper cylinder chamber 62A.

[0026] Passages 71, 72 that communicate between the upper cylinder chamber 62A and the lower cylinder chamber 62B are provided in the piston 65. A check valve 73 that allows fluid to flow only from the lower cylinder chamber 62B to the upper cylinder chamber 62A is provided in the passage 72, and a pressure reduction valve 74 that opens when the pressure of the fluid on the side of the upper cylinder chamber 62A reaches a predetermined pressure to reduce the pressure on the side of the lower cylinder chamber 62B is provided in the passage 71.

[0027] Passages 76, 75 that communicate between the lower cylinder chamber 62B and the reservoir 64 are provided in the base valve 70. A check valve 77 that allows fluid to flow only from the reservoir 64 to the lower cylinder chamber 62B is provided in the passage 75, and a pressure reduction valve 78 that opens when the pressure of the fluid on the side of the lower cylinder chamber 62B reaches a predetermined pressure to reduce the pressure on the side of the lower cylinder chamber 62B is provided in the passage 76.

[0028] The damping force generating mechanism 85 is configured to be connected to the cylinder upper chamber 62A on the upstream side 95u and to the storage container 64 on the downstream side 95d. The damping force generating mechanism 85 includes a substantially cylindrical housing (not shown) provided on the outer side of the cylinder 62, a pilot type main valve portion 87 on the inner side thereof, and a pilot valve portion 88 that controls the opening pressure of the main valve portion 87. The pilot valve portion 88 is driven by the electromagnetic solenoid 20 and functions as a pressure control valve. In addition, the electromagnetic solenoid 20 functions as a valve driving device.

[0029] The structure of the electromagnetic solenoid 20 will be described below. Figure 2 Figure 2 is a cross-sectional view of the electromagnetic solenoid 20 of the first embodiment of the present application.

[0030] The electromagnetic solenoid 20 mainly includes the bobbin 2, the solenoid coil 1 (coil) wound on the bobbin 2, the magnetic yoke 4 of the magnetic member disposed so as to cover the solenoid coil 1, the anchor 8, the housing 7, the upper core 5, the rod 9 disposed so as to slide in the center thereof between the housing 7 and the anchor 8 with the bush 12 interposed therebetween, and the armature 10 of the magnetic member disposed on the rod 9. The armature 10 of the first embodiment is configured to have a shorter length in the axial direction than in the radial direction.

[0031] The magnetic yoke 4 is formed in a cylindrical shape having a bottom portion 4D on the lower side in the vertical direction (axial direction) and has a through-hole 4B formed in the central portion thereof so as to pass through in the vertical direction (axial direction). The protrusion 4A extending upward in the vertical direction (axial direction) is formed in the central portion of the magnetic yoke 4. The protrusion 4A as a part of the magnetic yoke 4 is disposed between the bobbin 2 and the anchor 8.

[0032] The anchor 8 is formed in a cylindrical shape and is disposed so as to cover one side (lower side) of the armature 10 in the axial direction at a position located radially inward of the bobbin 2. The through-hole 8D that communicates in the vertical direction (axial direction) is formed in the central portion of the anchor 8. The rod 9 is inserted in the through-hole 8D. The protrusion 8C extending upward in the vertical direction (axial direction) is formed on the radially outer side of the anchor 8. The protrusion 8C is formed in a shape having an inclined portion that is longer on the radially central side and shorter on the radially outer side (outer periphery) when viewed in the cross section. In addition, a recess for disposing the bush 12 is provided in the lower portion of the through-hole 8D of the anchor 8. The anchor 8 is disposed so as to be press-fitted in the radially inner side (inner periphery side) of the through-hole 4B of the magnetic yoke 4.

[0033] ​On the upper surface of the bottom surface side of the yoke 4, a cylindrical member 6 of a non-magnetic body formed in a substantially cylindrical shape is fixedly arranged in a manner along the radially outer side (outer periphery) of the protruding portion 4A. That is, the cylindrical member 6 is arranged between the bobbin 2 and the armature 10. The outer diameter of the cylindrical member 6 is formed in a stepped shape, and has a small outer diameter portion 6E in which the outer diameter is made small on the upper side, and a large outer diameter portion 6F in which the outer diameter is made large on the lower side. The inner diameter of the cylindrical member 6 is composed of an upper large diameter portion 6A in which the diameter is large from the upper side, a small diameter portion 6B in which the diameter is formed small in a stepped shape, a diameter expansion portion 6C in which the diameter is expanded in a tapered shape, and a lower large diameter portion 6D in which the diameter is formed large in a stepped shape. The lower large diameter portion 6D is fitted in the radially outer side (outer periphery) of the protruding portion 4A of the yoke 4. Further, the diameter expansion portion 6C is formed so as to oppose the inclined portion of the protruding portion 8C of the anchor 8.

[0034] On the upper portion of the cylindrical member 6, a cylindrical housing 7 having a bottomed cylindrical hole is provided. The housing 7 is arranged in a manner so as to cover the other side of the armature 10 in the axial direction. The outer side portion of the housing 7 is fitted in the inner periphery of the upper large diameter portion 6A of the cylindrical member 6. The housing 7 is formed so as to have a large outer diameter portion 7B in which the outer diameter is larger than the lower end side, and further has a small outer diameter portion 7C in which the diameter is made small by providing a stepped portion on the upper side. The lower end of the housing 7 is arranged in a manner so as to contact the stepped portion of the inner diameter of the cylindrical member 6.

[0035] A bush 12 is arranged in the recessed portion of the lower portion of the through hole 8D of the anchor 8, and the rod 9 is supported in a manner so as to be movable in the up-down direction (axial direction) through the bush 12.

[0036] The armature 10, which is also called a movable iron core, is formed in a substantially cylindrical shape of a magnetic body of iron, and the rod 9 is fixed inside the cylinder. The outer diameter of the armature 10 is slightly smaller than the inner diameter of the protruding portion 8C of the anchor 8, and the armature 10 is arranged in a manner so as to be movable in the up-down direction inside the protruding portion 8C.

[0037] The rod 9 is formed in a cylindrical shape, and has a rod inner passage 9B which passes through the inside of the rod 9 in the axial direction (up-down direction).

[0038] The bobbin 2 includes a main body portion 2B which is arranged on the outer side of the housing 7 and the cylindrical member 6 in a cylindrical shape, and flange portions 2C, 2D which are formed on the upper and lower sides of the main body portion 2B, respectively, and extend to the radially outer side from the upper and lower end portions (axial end portions) of the main body portion 2B, respectively. The bobbin 2 is formed in a shape in which the radially outer side of the main body portion 2B is open, by having the flange portions 2C, 2D. Further, the bobbin 2 is formed of resin or the like.

[0039] The solenoid coil 1 is formed by winding a plurality of layers of a conductor such as a copper wire around the main body portion 2B of the bobbin 2 in a prescribed number of turns. In addition, the outer peripheral side of the solenoid coil 1 is insulated by molding with resin 3. The solenoid coil 1 wound around the main body portion 2B of the bobbin 2 is restricted from moving in the up-and-down direction by the flange portions 2C and 2D.

[0040] A recessed portion 2A is provided on the inner diameter side (radially inner side) of the lower end of the flange portion of the bobbin 2. A portion (large outer diameter portion 6F) of the cylindrical member 6 is inserted in this recessed portion 2A. The recessed portion 2A of the bobbin 2 and the portion (large outer diameter portion 6F) of the cylindrical member 6 are arranged in a manner of being stacked in the radial direction. In addition, the protruding portion 4A, which is a portion of the magnetic yoke 4, is arranged in a manner of being stacked in the radial direction with the recessed portion 2A of the bobbin 2 and the portion (large outer diameter portion 6F) of the cylindrical member 6.

[0041] A lead wire connected to the solenoid coil 1 is drawn out from the upper portion of the bobbin 2, which is not shown, and can be energized from the outside via a wiring portion.

[0042] In the upper portion of the housing 7, the upper core 5 is arranged. The upper core 5 is shaped in a manner of a cylindrical portion protruding downward from a circular plate, and is formed so as to be housed in the inner diameter side of the cylinder of the small outer diameter portion 7C of the housing 7. The outer side of the circular plate is fixed to the upper end of the magnetic yoke 4 by fastening or the like. In addition, on the inner diameter side of the cylindrical hole of the housing 7, the rod 9 is supported in a manner of being movable in the up-and-down direction (axial direction) by the bushing 11.

[0043] An oil chamber of a pilot valve portion 88 is formed in the lower portion of the magnetic yoke 4, and a valve body is arranged in the lower portion of the rod 9 in the oil chamber, and the valve is opened and closed and the pressure is controlled in accordance with the up-and-down movement of the rod 9, but this is not shown. Therefore, the oil chamber 13 formed around the armature 10 and the back pressure chamber 14 of the upper end of the rod are in communication with the oil chamber of the pilot valve portion 88, and are filled with fluid. In addition, the oil chamber 13 is the range of movement of the armature 10 in the axial direction. The armature 10 is in a position in which the recessed portion 2A of the bobbin 2 and the large outer diameter portion 6F of the cylindrical member 6 are radially superimposed in a state in which it is located on the lower side in the axial direction, and is in a position in which the recessed portion 2A of the bobbin 2 and the large outer diameter portion 6F of the cylindrical member 6 are not radially superimposed in a state in which it is located on the upper side in the axial direction. That is, the armature 10 is movable in the axial direction to be in a position in which the recessed portion 2A of the bobbin 2 and the large outer diameter portion 6F of the cylindrical member 6 are stacked in the radial direction, and a position in which they are not stacked. In the first embodiment, therefore, it is possible to secure a necessary range of movement in the axial direction of the electromagnetic solenoid 20 while suppressing the increase in size of the electromagnetic solenoid 20, so it is possible to expand the range of application of components and products.

[0044] For the cylindrical component 6 and the housing 7, brazing filler metal is positioned at the inner circumferential side 31 at the upper end of the cylinder and brazed by heating. Additionally, for the magnetic yoke 4 and the cylindrical component 6, brazing filler metal is positioned at the outer circumferential side 30 at the lower end of the cylinder and brazed by heating. This structure prevents fluid leakage from the inner side of the housing 7 and the upper end of the anchor 8 towards the solenoid coil 1.

[0045] Next, the operation of the shock absorber 61 will be explained. During the extension stroke of the piston rod 66, the piston 65 moves within the cylinder 62, closing the check valve 73 of the piston 65. Before the pressure reducing valve 74 opens, the fluid on the upper chamber 62A side of the cylinder is pressurized and flows into the damping force generating mechanism 85. The flowing fluid then flows into the storage container 64 through the main valve section 87 and the pilot valve section 88.

[0046] At this time, fluid equivalent to the movement of piston 65 flows from storage container 64 through check valve 77 of base valve 70 into cylinder lower chamber 62B. When the pressure in cylinder upper chamber 62A reaches the opening pressure of pressure reducing valve 74 of piston 65, the pressure reducing valve 74 is opened to reduce the pressure in cylinder upper chamber 62A to cylinder lower chamber 62B, preventing excessive pressure rise in cylinder upper chamber 62A.

[0047] During the retraction stroke of piston rod 66, the movement of piston 65 within cylinder 62 causes check valve 73 of piston 65 to open, while check valve 77 of passage 75 of base valve 70 closes. Before pressure reducing valve 78 opens, fluid in lower chamber 62B flows to upper chamber 62A. The amount of fluid equivalent to the amount of fluid entering cylinder 62 by piston rod 66 flows from upper chamber 62A to storage container 64 via the same path as during the extension stroke. When the pressure in lower chamber 62B reaches the opening pressure of pressure reducing valve 78 of base valve 70, pressure reducing valve 78 opens, reducing the pressure in lower chamber 62B to the storage container 64, thereby preventing excessive pressure rise in lower chamber 62B.

[0048] Therefore, during the extension and retraction stroke of the piston rod 66, in the damping force generating mechanism 85, before the main valve section 87 opens (in the low-speed range of the piston), a damping force relative to the piston 65 is generated through the pilot valve section 88, and after the main valve section 87 opens (in the high-speed range of the piston), a damping force is generated corresponding to its opening degree. Furthermore, the damping force can be adjusted by regulating the control pressure of the pilot valve section 88 using the current supplied to the solenoid coil 1. As a result, the change in internal pressure of the back pressure chamber (not shown) of the main valve section 87 allows for the adjustment of the opening pressure and opening degree of the main valve section 87.

[0049] Next, the operation of the electromagnetic solenoid 20 will be described. When the solenoid coil 1 is energized, the solenoid coil 1 is excited, and a magnetic flux flows as indicated by the line M in the drawing, generating a thrust in the direction of attracting the armature 10 in the axial direction between the armature 10 and the anchor 8. At this time, in order to efficiently generate the thrust, it is necessary to make the magnetic flux flow mainly from the lower side of the housing 7 through the armature 10, the protruding portion 8C of the anchor 8, or the upper surface 8A of the convex portion 4A. For this purpose, it is necessary to provide a non-magnetic portion between the lower side of the housing 7 and the protruding portion 8C of the anchor 8, and the cylindrical member 6 plays a role.

[0050] In addition, since the protruding portion 8C needs to concentrate the magnetic flux, it is also necessary to make the outer diameter side of the protruding portion 8C a non-magnetic body. The cylindrical member 6 on the outer diameter side of the protruding portion 8C plays a role.

[0051] On the other hand, the outer peripheral side of the oil chamber 13 located around the armature 10 needs to be configured so that the fluid does not leak to the solenoid coil 1 side. In addition, since the pressure of the oil chamber 13 rises, the components around it need to have strength capable of maintaining the pressure, and deformation caused by the pressure needs to be suppressed as much as possible. In addition, since the anchor 8 is pressed into the yoke 4, deformation at the time of pressing needs to be suppressed.

[0052] Therefore, the protruding portion 8C and the convex portion 4A of the yoke need to have a necessary thickness. On the other hand, in the case where the thrust is to be increased, it is possible to consider increasing the diameter of the armature 10 and increasing the number of turns of the solenoid coil 1. If the diameter of the armature 10 is simply increased, the inner diameter side of the solenoid coil 1 will increase, resulting in a decrease in the area of the solenoid coil 1, but in the first embodiment, the recess 2A is provided on the inner side of the lower end of the bobbin 2, and is configured so as to accommodate the large outer diameter portion 6F of the cylindrical member 6 in this portion. In addition, the recess formed in the diameter enlarged portion 6C on the inner diameter side of the cylindrical member 6 is configured so as to accommodate the convex portion 4A of the yoke 4, and further, the protruding portion 8C of the anchor 8 is disposed on the inner side of the cylindrical member 6, and thus a structure can be configured in which the strength of the convex portion of the yoke 4 and the protruding portion 8C of the anchor 8 can be ensured without reducing the area required for the solenoid coil 1. Thus, the diameter of the armature 10 can be increased without reducing the area of the solenoid coil 1, and if the number of turns is the same, the thrust can be increased. Therefore, if the outer diameter of the electromagnetic solenoid 20 is the same, the thrust can be increased by increasing the diameter of the armature 10 without reducing the number of turns required for the solenoid coil 1. In addition, if the required thrust is the same, the number of turns of the solenoid coil can be reduced, and by reducing the length and the outer diameter in the axial direction, the solenoid can be made smaller.

[0053] In addition, in the case where the solenoid coil 1 of the first embodiment is used for a damping force adjustment type shock absorber, by shortening the axial length, shortening the outer diameter, or the like, mountability to a vehicle or the like can be improved, and the degree of freedom of arrangement can be increased. In addition, since the thrust can be increased, the damping force adjustment range can be further increased.

[0054] Embodiment 2

[0055] For the second embodiment of the present application, reference will be made to Figure 3 for an explanation. Figure 3 is a cross-sectional view of an electromagnetic solenoid of the second embodiment of the present application. For the structures common to the first embodiment, the same reference numerals are assigned, and detailed descriptions thereof will be omitted.

[0056] In the second embodiment, the shape of the portion in which the bobbin and the solenoid coil 1 are accommodated is different from that of the first embodiment.

[0057] As Figure 3 shown, in the flange portion 2D located on the lower side of the bobbin 2, a stepped portion 2E is formed so as to be stepped downward (axially outward). The solenoid coil 1 is wound at the position of the stepped portion 2E. That is, by forming the stepped portion 2E which is stepped downward (axially outward) compared to the upper surface of the flange portion 2D, the number of turns of the solenoid coil 1 wound on the bobbin 2 can be increased. In addition, a recess portion 2A is formed on the radially inner side of the stepped portion 2E.

[0058] According to the second embodiment, the same effects as those of the first embodiment can be obtained, and since the solenoid coil 1 can be wound more in the portion of the stepped portion 2E, the thrust can be further increased, and accordingly the axial length can be shortened, the diameter can be shortened, and further miniaturization can be achieved.

[0059] Embodiment 3

[0060] For the third embodiment of the present application, reference will be made to Figure 4 for an explanation. Figure 4 is a cross-sectional view of an electromagnetic solenoid of the third embodiment of the present application. For the structures common to the first embodiment and the second embodiment, the same reference numerals are assigned, and detailed descriptions thereof will be omitted.

[0061] In the third embodiment, mainly the shapes of the anchor 8, the yoke 4, and the cylindrical member 6 are different from those of the first embodiment and the second embodiment.

[0062] The anchor 8 is formed in a cylindrical shape, and a through-hole 8D that communicates in the up-down direction (axial direction) is formed in the central portion. In the central portion of the anchor 8 in the first embodiment and the second embodiment, a protruding portion 8C that extends upward in the up-down direction (axial direction) is formed, but in the third embodiment, the protruding portion 8C is not formed, which is different from the first embodiment and the second embodiment.

[0063] The magnetic yoke 4 is formed in a cylindrical shape having a bottom portion 4D on the lower side in the up-down direction (axial direction), and a through-hole 4B that penetrates in the up-down direction (axial direction) is formed in the central portion. In the central portion of the magnetic yoke 4, a protruding portion 4C that extends upward in the up-down direction (axial direction) is formed. The protruding portion 4C is formed in a shape having an inclined portion that is higher on the radially central side and lower on the radially outer side when viewed in cross section.

[0064] On the upper surface of the bottom portion 4D of the magnetic yoke 4, a cylindrical member 6 of a non-magnetic body is fixedly disposed in a manner so as to follow the radially outer side (outer periphery) of the protruding portion 4C.

[0065] The cylindrical member 6 is formed in a substantially cylindrical shape. The outer diameter of the cylindrical member 6 is formed in a stepped shape, and has a small outer diameter portion 6E in which the diameter on the upper side in the up-down direction (axial direction) is formed to be small, and a large outer diameter portion 6F in which the diameter on the lower side in the up-down direction (axial direction) is formed to be large. The inner diameter of the cylindrical member 6 is composed of an upper large diameter portion 6A in which the diameter is large from the upper side in the axial direction, a small diameter portion 6B in which the diameter is formed to be small in a stepped manner from the upper large diameter portion 6A, a diameter expanding portion 6C in which the diameter is formed to be tapered and enlarged from the small diameter portion 6B, and a lower large diameter portion 6D that is continuous with the diameter expanding portion 6C. The lower large diameter portion 6D is fitted in the radially outer side (outer periphery) of the protruding portion 4C of the magnetic yoke 4. In addition, the diameter expanding portion 6C is formed so as to oppose the inclined portion of the protruding portion 8C of the magnetic yoke 4.

[0066] According to the above structure, in the third embodiment, the same effects as in the first embodiment can be obtained, and further, the protruding portion 8C of the magnetic yoke 4 can be made to have a thickness, and deformation of the protruding portion 8C at the time of press-fitting or brazing can be suppressed. Furthermore, in the third embodiment, deformation at the time of hydraulic pressure generation can also be suppressed.

[0067] In the first embodiment to the third embodiment, the magnetic yoke 4 and the anchor 8 are configured in a divided manner, but the magnetic yoke 4 and the anchor 8 can also be configured in an integrated manner. In this case, the protruding portion 4C and the protruding portion 8C are configured in an integrated manner.

[0068] In addition, the present application is not limited to the above-described embodiments, and various modifications are included. The above-described embodiments are described in detail in order to easily understand the present application, and are not limited to necessarily having all the structures described.

[0069] Explanation of Reference Signs

[0070] 1 solenoid coil, 2 bobbin, 2A recess, 3 resin, 4 yoke, 5 upper core, 6 cylindrical member, 6F large outer diameter portion, 7 housing, 8 anchor, 9 rod, 10 armature, 11, 12 bush, 13 oil chamber, 20 electromagnetic solenoid, 61 shock absorber, 62 cylinder, 64 storage container, 85 damping force generation mechanism, 87 main valve portion, 88 pilot valve portion

Claims

1. A valve driving device of a damping force adjustable shock absorber, characterized by, including: a bobbin having a cylindrical main body; a coil wound around the main body of the bobbin; an anchor fixed to a shaft, disposed on a radially inner side of the bobbin; an anchor fixed to a shaft, disposed on a radially inner side of the bobbin; a magnetic yoke disposed between the bobbin and the anchor; and a cylindrical member disposed between the bobbin and the anchor, the bobbin forms a recess on a radially inner side, a portion of the cylindrical member is inserted into the recess, a portion of the cylindrical member and the recess are disposed in a radially laminated manner, the anchor is axially movable between a position where a portion of the cylindrical member and the recess are radially laminated and a position where they are not laminated, the cylindrical member is a non-magnetic body, an outer diameter of the cylindrical member includes a small outer diameter portion and a large outer diameter portion formed in a stepped shape, an inner diameter of the cylindrical member is composed of an upper large diameter portion having a larger diameter, a small diameter portion having a diameter that is stepwisely smaller, a diameter expansion portion having a diameter that is stepwisely expanded, and a lower large diameter portion having a diameter that is stepwisely larger, from the other side in the axial direction, the large outer diameter portion is disposed in the recess of the bobbin, and a convex portion of the magnetic yoke is received in the recess formed by the diameter expansion portion.

2. The valve drive device according to claim 1, characterized by: including a cylindrical housing covering the other side in the axial direction of the anchor, the housing is fitted in the cylindrical member.

3. The valve drive device according to claim 1, characterized by: a portion of the magnetic yoke is disposed in a radially laminated manner with the recess and a portion of the cylindrical member.

4. The valve drive device according to claim 1, characterized by: the magnetic yoke and the cylindrical member are brazed.

5. The valve drive device according to claim 1, characterized by: the anchor and the magnetic yoke are integrated.

6. The valve drive device according to claim 1, characterized by: the bobbin has flange portions extending to a radially outer side from axial end portions of the main body, a step portion is formed in the flange portions to an axially outer side in a stepped shape, the recess is formed on a radially inner side of the step portion.

7. The valve drive device according to claim 1, characterized by: the magnetic yoke is disposed in a manner of covering around the coil.

8. A shock absorber, comprising: a cylinder; a piston slidable within the cylinder, partitioning the cylinder into an upper cylinder chamber and a lower cylinder chamber; a piston rod coupled to the piston; reservoirs connected to the upper cylinder chamber and the lower cylinder chamber, respectively; and a damping force generating mechanism provided between the cylinder and the reservoirs, the shock absorber is characterized by: the damping force generating mechanism includes a pilot valve portion that adjusts a damping force applied to the piston, and a valve drive device that controls the pilot valve portion, the valve drive device is the valve drive device according to any one of claims 1 to 7.

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