Patent Publication Number: US-2023160451-A1

Title: Valve driving device and shock absorber using the same

Description:
TECHNICAL FIELD 
     The present invention relates to a valve driving device and a shock absorber using the same. 
     BACKGROUND ART 
     A conventional damping force adjustment type shock absorber includes, for example, a technique described in Patent Literature 1. The damping force adjustment type shock absorber described in Patent Literature 1 includes a damping force generation means that generates a damping force therein and a solenoid case in which a solenoid that drives the damping force generation means is accommodated. The flow of working fluid accompanying the movement of the piston in the cylinder is controlled by the damping force generation means in the solenoid case. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP 2019-27460 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     The solenoid that drives the damping force generation means includes a coil wound around a bobbin, a pair of cores inserted into the coil, a plunger supported movably in the axial direction between the pair of cores, and an operating rod coupled to the plunger. 
     In the damping force adjustment type shock absorber, thrust is required to be increased in order to increase an adjustment range of the damping force. In addition, the size of the damping force adjustment type shock absorber is required to be reduced to improve mountability to a vehicle or the like. 
     In order to increase the thrust in the damping force adjustment type shock absorber, the diameter of the plunger needs to be increased. In the technique described in Patent Literature 1, when an attempt is made to increase the diameter of the plunger, the inner diameter of the coil also has to be increased, and the core and the solenoid case are also increased accordingly, whereby the size of the shock absorber increases. 
     An object of the present invention is to solve the above problems, and to provide a valve driving device capable of suppressing an increase in size and improving thrust, and a shock absorber using the same. 
     Solution to Problem 
     In order to achieve the above object, the present invention provides a valve driving device for a damping force adjustment type shock absorber, the valve driving device including a bobbin with a cylindrical body portion; a coil wound around the body portion of the bobbin; an armature that is arranged on a radially inner side of the bobbin and fixed to a rod; an anchor that covers one side in an axial direction of the armature at a position on a radially inner side of the bobbin; a yoke partially arranged between the bobbin and the anchor; and a cylindrical member arranged between the bobbin and the armature, where the bobbin includes a recessed portion on the radially inner side, a part of the cylindrical member is inserted into the recessed portion, the one part of the cylindrical member and the recessed portion are arranged so as to be laminated in the radial direction, and the armature operates in an axial direction to take a position where the one part of the cylindrical member and the recessed portion are laminated and a position where the one part of the cylindrical member and the recessed portion are not laminated in the radial direction. 
     Advantageous Effects of Invention 
     According to the present invention, a valve driving device capable of suppressing an increase in size and improving thrust, and a shock absorber using the same can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram illustrating a hydraulic circuit of a main component in a shock absorber according to a first example of the present invention. 
         FIG.  2    is a cross-sectional view of an electromagnetic solenoid according to the first example of the present invention. 
         FIG.  3    is a cross-sectional view of an electromagnetic solenoid according to a second example of the present invention. 
         FIG.  4    is a cross-sectional view of an electromagnetic solenoid according to a third example of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, examples of a shock absorber according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following examples, and various modifications and application examples are included in the scope of the technical concept of the present invention. 
     First Example 
     A first example of the present invention will be described with reference to  FIGS.  1  and  2   .  FIG.  1    is a diagram illustrating a hydraulic circuit of a main component in a shock absorber according to a first example of the present invention. In  FIG.  1   , a damping force adjustment type shock absorber is configured. In the following description, an upward direction (upper side) and a downward direction (lower side) in  FIG.  1    are referred to as an upward direction (upper side) and a downward direction (lower side) in a shock absorber  61 , and the vertical direction is illustrated in each drawing. In addition, a direction in which a rod  9  extends (vertical direction) is referred to as an axial direction, a direction orthogonal to the axial direction of the rod  9  is referred to as a radial direction, a direction approaching the rod  9  is referred to as a radially inner side, and a direction separating from the rod  9  is referred to as a radially outer side.  FIG.  2    is a cross-sectional view of an electromagnetic solenoid according to the first example of the present invention. 
     As shown in  FIG.  1   , the shock absorber  61  of the first example is configured by a tubular cylinder  62 , a reservoir  64 , and a damping force generation means  85 . The shock absorber  61  is mounted between two relatively movable members on a sprung (vehicle body) side, an unsprung (wheel) side, and the like of a suspension device of a vehicle (not illustrated). 
     A piston  65  is slidably fitted in the cylinder  62 , so that the inside of the cylinder  62  is divided into a cylinder upper chamber  62 A and a cylinder lower chamber  62 B by the piston  65 . 
     A piston rod  66  is coupled to the piston  65 , and an end of the piston rod  66  on a side opposite to the piston  65  passes through the cylinder upper chamber  62 A and projects out to the outside of the cylinder  62  through an oil seal (not illustrated). On the lower end side of the cylinder  62 , a base valve  70  that divides the cylinder lower chamber  62 B and the reservoir  64  is provided. 
     One of the reservoirs  64  is connected to the cylinder upper chamber  62 A of the cylinder  62 , and the other reservoir  64  is connected to the cylinder lower chamber  62 B of the cylinder  62  by way of the base valve  70 . A damping force generation means  85  is provided between the cylinder  62  and the reservoir  64 . In the first example, the damping force generation means  85  is connected between one of the reservoirs  64  and the cylinder upper chamber  62 A. 
     The piston  65  is provided with passages  71  and  72  that communicate the cylinder upper chamber  62 A and the cylinder lower chamber  62 B. The passage  72  is provided with a check valve  73  that allows only the flow of fluid from the cylinder lower chamber  62 B to the cylinder upper chamber  62 A, and the passage  71  is provided with a relief valve  74  that opens when the pressure of the fluid on the cylinder upper chamber  62 A side reaches a predetermined pressure and relieves the fluid toward the cylinder lower chamber  62 B side. 
     The base valve  70  is provided with passages  76  and  75  that communicate the cylinder lower chamber  62 B and the reservoir  64 . The passage  75  is provided with a check valve  77  that allows only the flow of fluid from the reservoir  64  to the cylinder lower chamber  62 B, and the passage  76  is provided with a relief valve  78  that opens when the pressure of the fluid on the cylinder lower chamber  62 B side reaches a predetermined pressure and relieves the fluid toward the cylinder lower chamber  62 B side. 
     In the damping force generation means  85 , the upstream side  95   u  is connected to the cylinder upper chamber  62 A side, and the downstream side  95   d  is connected to the reservoir  64 . The damping force generation means  85  is configured by a substantially cylindrical case (not illustrated) on an outer side of the cylinder  62 , a pilot-type main valve unit  87  on the inner side thereof, and a pilot valve unit  88  that controls the valve opening pressure of the main valve unit  87 . The pilot valve unit  88  is driven by an electromagnetic solenoid  20  and functions as a pressure control valve. The electromagnetic solenoid  20  functions as a valve driving device. 
     The structure of the electromagnetic solenoid  20  will be described with reference to  FIG.  2   .  FIG.  2    is a cross-sectional view of an electromagnetic solenoid  20  according to the first example of the present invention. 
     The electromagnetic solenoid  20  mainly includes a bobbin  2 , a solenoid coil  1  (coil) wound around the bobbin  2 , a yoke  4 , an anchor  8 , a housing  7 , and an upper core  5  of a magnetic member arranged so as to cover the periphery of the solenoid coil  1 , a rod  9  arranged so as to slidably move between the housing  7  and the anchor  8  by way of a bush  12  at the center thereof, and an armature  10  of a magnetic member fixedly arranged on the rod  9 . The armature  10  of the first example is configured such that the axial length is shorter than the radial length (diameter). 
     The yoke  4  is formed in a cylindrical shape having a bottom portion  4 D on the lower side in the vertical direction (axial direction), and a through hole  4 B penetrating in the vertical direction (axial direction) is formed at the center portion. A convex portion  4 A extending toward the upper side in the vertical direction (axial direction) is formed at the center portion of the yoke  4 . The convex portion  4 A, which is a part of the yoke  4 , is arranged between the bobbin  2  and the anchor  8 . 
     The anchor  8  is formed in a cylindrical shape and is arranged to cover one side (lower side) in the axial direction of the armature  10  at a position on the radially inner side of the bobbin  2 . A through hole  8 D communicating in the vertical direction (axial direction) is formed at a center portion of the anchor  8 . The rod  9  is inserted into the through hole  8 D. A protruding portion  8 C extending upward in the vertical direction (axial direction) is formed on the radially outer side of the anchor  8 . The protruding portion  8 C has a shape having an inclined portion in which a radially central side is long and a radially outer side (outer periphery) is short when viewed in a cross section. A recessed portion in which the bush  12  is arranged is provided at a lower part of the through hole  8 D of the anchor  8 . The anchor  8  is arranged in a manner of being press-fitted into the radially inner side (inner peripheral side) of the through hole  4 B of the yoke  4 . 
     A cylindrical member  6  of a non-magnetic body and formed in a substantially cylindrical shape is fixedly arranged so as to lie along a radially outer side (outer periphery) of the convex portion  4 A on an upper surface on a bottom surface side of the yoke  4 . 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 form and includes a small outer diameter portion  6 E having a small outer diameter on the upper side, and a large outer diameter portion  6 F having a large outer diameter on the lower side. The inner diameter of the cylindrical member  6  is configured of, from the top, an upper large diameter portion  6 A having a large diameter, a small diameter portion  6 B formed by decreasing the diameter in a stepped form, a diameter enlarged portion  6 C formed by increasing the diameter in a tapered form, and a lower large diameter portion  6 D formed by increasing the diameter in a stepped form. The lower large diameter portion  6 D is fitted to the radially outer side (outer periphery) of the convex portion  4 A of the yoke  4 . The diameter enlarged portion  6 C is formed so as to face the inclined portion of the protruding portion  8 C of the anchor  8 . 
     A bottomed cylindrical housing  7  having a cylindrical hole is provided on an upper part of the cylindrical member  6 . The housing  7  is arranged so as to cover the other side in the axial direction of the armature  10 . The outer side of the housing  7  is fitted to the inner periphery of the upper large diameter portion  6 A of the cylindrical member  6 . The housing  7  is formed to have a large outer diameter portion  7 B in which the outer diameter has a larger diameter than the lower end side, and a small outer diameter portion  7 C in which a step portion is provided so that the diameter is smaller on the upper side. The lower end of the housing  7  is arranged so as to come into contact with the step portion of the inner diameter of the cylindrical member  6 . 
     A bush  12  is arranged in a recessed portion at the lower part of the through hole  8 D of the anchor  8 , and the rod  9  is supported to be movable in the vertical direction (axial direction) by way of the bush  12 . 
     The armature  10 , which is also referred to as a movable iron core, is formed in a substantially cylindrical shape by an iron-based magnetic body, and the rod  9  is fixed to the inner side of the cylinder. The outer diameter of the armature  10  is slightly smaller than the inner diameter of the protruding portion  8 C of the anchor  8 , and is arranged so as to be movable in the vertical direction on the inner side. 
     The rod  9  is formed in a cylindrical shape and has an in-rod passage  9 B penetrating the rod  9  in the axial direction (vertical direction). 
     The bobbin  2  is arranged on the outer side of the housing  7  and the cylindrical member  6 , and includes a cylindrical body portion  2 B and flange portions  2 C and  2 D formed above and below the body portion  2 B and respectively extending to the radially outer side from upper and lower ends (axial ends) of the body portion  2 B. Since the bobbin  2  includes the flange portions  2 C and  2 D, the radially outer side of the body portion  2 B is opened. The bobbin  2  is made of resin or the like. 
     The solenoid coil  1  is configured by winding a conductor such as a copper wire around the body portion  2 B of the bobbin  2  in multiple layers by a predetermined number of turns. The outer peripheral side of the solenoid coil  1  is insulated by molding with the resin  3 . The movement of the solenoid coil  1  wound around the body portion  2 B of the bobbin  2  is regulated in the vertical direction by the flange portions  2 C and  2 D. 
     A recessed portion  2 A is provided on a lower end inner diameter side (radially inner side) of the flange portion of the bobbin  2 . A part (large outer diameter portion  6 F) of the cylindrical member  6  is inserted into the recessed portion  2 A. The recessed portion  2 A of the bobbin  2  and the one part (large outer diameter portion  6 F) of the cylindrical member  6  are arranged so as to be laminated in the radial direction. The convex portion  4 A, which is a part of the yoke  4 , is arranged so as to be laminated with the recessed portion  2 A of the bobbin  2  and the one part (large outer diameter portion  6 F) of the cylindrical member  6  in the radial direction. 
     The lead wire connected to the solenoid coil  1  is taken out from the upper part of the bobbin  2  (not illustrated), and can be energized from the outside via a wire connecting portion. 
     An upper core  5  is arranged at the upper part of the housing  7 . The upper core  5  has a shape in which a cylindrical portion projects out to the lower side from a circular plate, and is formed such that the small outer diameter portion  7 C of the housing  7  is accommodated on the inner diameter side of the cylinder. The outer side of the circular plate is fixed to the upper end of the yoke  4  by caulking or the like. On the inner diameter side of the cylindrical hole of the housing  7 , the rod  9  is supported so as to be movable in the vertical direction (axial direction) by way of a bush  11 . 
     Although not illustrated, an oil chamber of a pilot valve unit  88  is formed at a lower part of the yoke  4 , a valve valve body is arranged at a lower part of the rod  9  in the oil chamber, and the valve is opened and closed with the vertical operation of the rod  9  to control the pressure. Therefore, the oil chamber  13  formed around the armature  10  and the back pressure chamber  14  at the upper end of the rod communicate with the oil chamber of the pilot valve unit  88  and are filled with fluid. The oil chamber  13  is a moving range in the axial direction of the armature  10 . The armature  10  is located at a position where the recessed portion  2 A of the bobbin  2  and the large outer diameter portion  6 F of the cylindrical member  6  overlap in the radial direction in a state of being located on the axially lower side, and is located at a position where the recessed portion  2 A of the bobbin  2  and the large outer diameter portion  6 F of the cylindrical member  6  do not overlap in the radial direction in a state of being located on the axially upper side. That is, the armature  10  operates in the axial direction so as to be able to take a position where the recessed portion  2 A of the bobbin  2  and the large outer diameter portion  6 F of the cylindrical member  6  are laminated and a position where they are not laminated in the radial direction. In the first example, a necessary operation range can be secured in the axial direction of the electromagnetic solenoid  20  while suppressing an increase in size of the electromagnetic solenoid  20 , and thus a range of component and product application can be expanded. 
     The cylindrical member  6  and the housing  7  are brazed by heating with a brazing material arranged at a position on the inner peripheral side  31  of the upper end of the cylinder. The yoke  4  and the cylindrical member  6  are brazed by heating with a brazing material arranged at a position on the outer peripheral side  30  of the lower end of the cylinder. With this configuration, the fluid is suppressed from leaking from the housing  7  or the inner side of the upper end of the anchor  8  to the solenoid coil  1  side. 
     Next, the operation of the shock absorber  61  will be described. In the extension stroke of the piston rod  66 , the check valve  73  of the piston  65  is closed by the movement of the piston  65  in the cylinder  62 , and before the opening of the relief valve  74 , the fluid on the cylinder upper chamber  62 A side is pressurized to flow into the damping force generation means  85 . The flowed fluid flows into the reservoir  64  through the main valve unit  87  and the pilot valve unit  88 . 
     At this time, the fluid worth the movement of the piston  65  opens the check valve  77  of the base valve  70  from the reservoir  64  and flows into the cylinder lower chamber  62 B. When the pressure of the cylinder upper chamber  62 A reaches the valve opening pressure of the relief valve  74  of the piston  65 , the relief valve  74  opens to relieve the pressure of the cylinder upper chamber  62 A to the cylinder lower chamber  62 B, thereby preventing an excessive increase in the pressure of the cylinder upper chamber  62 A. 
     In the contraction stroke of the piston rod  66 , the check valve  73  of the piston  65  is opened and the check valve  77  of the passage  75  of the base valve  70  is closed by the movement of the piston  65  in the cylinder  62 , and before the opening of the relief valve  78 , the fluid in the cylinder lower chamber  62 B flows into the cylinder upper chamber  62 A, and the fluid worth the amount of the piston rod  66  entering the cylinder  62  flows from the cylinder upper chamber  62 A to the reservoir  64  through the path same as in the extension stroke described above. When the pressure in the cylinder lower chamber  62 B reaches the valve opening pressure of the relief valve  78  of the base valve  70 , the relief valve  78  opens to relieve the pressure of the cylinder lower chamber  62 B to the reservoir  64 , thereby preventing an excessive increase in the pressure in the cylinder lower chamber  62 B. 
     As a result, at the time of the expansion/contraction strokes of the piston rod  66 , in the damping force generation means  85 , the pilot valve unit  88  generates a damping force with respect to the piston  65  before the opening of the main valve unit  87  (piston speed low speed region), and generates the damping force according to the opening degree after the opening of the main valve unit  87  (piston speed high speed region side). The damping force can be adjusted by adjusting the control pressure of the pilot valve unit  88  by the energizing current to the solenoid coil  1 . As a result, the internal pressure of the back pressure chamber (not illustrated) of the main valve unit  87  changes, and the valve opening pressure and the opening degree of the main valve unit  87  can be adjusted. 
     Next, the operation of the electromagnetic solenoid  20  will be described. When the solenoid coil  1  is energized, the solenoid coil  1  is excited, a flow of magnetic flux is generated by a magnetic field generated by the excitation as indicated by a line M in the drawing, and thrust in a direction of attracting to the anchor  8  in the axial direction is generated in the armature  10 . At this time, it is necessary to cause the flow of the magnetic flux to mainly pass through the armature  10 , the protruding portion  8 C of the anchor  8 , or the upper surface  8 A of the convex portion  4 A from the lower side of the housing  7  in order to efficiently generate the thrust. For this purpose, a non-magnetic portion is required between the lower side of the housing  7  and the protruding portion  8 C of the anchor  8 , and the cylindrical member  6  plays that role. 
     In addition, since the protruding portion  8 C needs to concentrate the magnetic flux, the outer diameter side of the protruding portion  8 C also needs to be a non-magnetic body. The cylindrical member  6  on the outer diameter side of the protruding portion  8 C plays such a role. 
     On the other hand, it is necessary to prevent the fluid from leaking to the solenoid coil  1  side on the outer peripheral side of the oil chamber  13  around the armature  10 . In addition, since the pressure of the oil chamber  13  increases, the members around the oil chamber need to have the strength to be able to hold the pressure, and deformation due to the pressure is desirably suppressed as much as possible. Furthermore, since the anchor  8  is press-fitted into the yoke  4 , deformation at the time of press-fitting needs to be suppressed. 
     Therefore, the protruding portion  8 C and the convex portion  4 A of the yoke need to have a necessary thickness. On the other hand, when increasing the thrust, it is conceivable to increase the diameter of the armature  10  and increase the number of windings of the solenoid coil  1 . When the diameter of the armature  10  is simply increased, the area of the solenoid coil  1  is reduced by increasing the inner diameter side of the solenoid coil  1 , but in the first example, the recessed portion  2 A is provided on the inner side at the lower end of the bobbin  2  and the large outer diameter portion  6 F of the cylindrical member  6  is arranged to be accommodated in that portion. Furthermore, since the convex portion  4 A of the yoke  4  is arranged so as to be accommodated in the recessed portion formed in the diameter enlarged portion  6 C corresponding to the inner diameter side of the cylindrical member  6 , and the protruding portion  8 C of the anchor  8  is arranged on the inner side of the cylindrical member  6 , a structure that allows the strength of the convex portion of the yoke  4  and the protruding portion  8 C of the anchor  8  to be secured without reducing the area required for the solenoid coil  1  is obtained. As a result, the diameter of the armature  10  can be increased without reducing the area of the solenoid coil  1 , and the thrust can be increased if the number of windings is the same. 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 windings required for the solenoid coil  1 . In addition, when the required thrust is the same, the number of windings of the solenoid coil can be reduced, and downsizing can be achieved by reducing the axial length and the outer diameter. 
     In addition, in a case where the solenoid coil  1  of the first example is used in a damping force adjustment type shock absorber, it is possible to improve mountability to a vehicle or the like and increase a degree of freedom of arrangement by shortening an axial length, shortening an outer diameter, or the like. Furthermore, since the thrust can be increased, there is an advantage that the damping force adjustment range can be further increased. In addition, if the generated thrust is the same, the required current can be reduced, and energy saving can be achieved. 
     Second Example 
     A second example of the present invention will be described with reference to  FIG.  3   .  FIG.  3    is a cross-sectional view of an electromagnetic solenoid according to the second example of the present invention. Configurations common to the first example are denoted with the same reference numerals, and a detailed description thereof will be omitted. 
     The second example is different from the first example in the shape of the portion in which the bobbin and the solenoid coil  1  are accommodated. 
     As illustrated in  FIG.  3   , the flange portion  2 D located on the lower side of the bobbin  2  is provided with a step portion  2 E formed in a stepped form toward the lower side (axially outer side). The solenoid coil  1  is wound at the position of the step portion  2 E. That is, by forming the step portion  2 E lowered in a stepped form toward the lower side (axially outer side) from the upper surface of the flange portion  2 D, the number of windings of the solenoid coil  1  wound around the bobbin  2  can be increased. A recessed portion  2 A is provided on the radially inner side of the step portion  2 E. 
     According to the second example, effects similar to those of the first example can be obtained, and at the same time, the solenoid coil  1  can be wound more around the portion of the step portion  2 E, so that the thrust can be further improved, the axial length can be shortened and the diameter can be reduced accordingly, and the size can be further reduced. 
     Third Example 
     A third example of the present invention will be described with reference to  FIG.  4   .  FIG.  4    is a cross-sectional view of an electromagnetic solenoid according to the third example of the present invention. Configurations common to the first example and the second example are denoted with the same reference numerals, and a detailed description thereof will be omitted. 
     The third example is different from the first and second examples mainly in the shapes of an anchor  8 , a yoke  4 , and a cylindrical member  6 . 
     The anchor  8  is formed in a cylindrical shape, and a through hole  8 D communicating in the vertical direction (axial direction) is formed at the center portion. The protruding portion  8 C extending toward the upper side in the vertical direction (axial direction) is formed at the center portion of the anchor  8  in the first example and the second example, but the third example is different from the first example and the second example in that the protruding portion  8 C is not formed. 
     The yoke  4  is formed in a cylindrical shape having a bottom portion  4 D on the lower side in the vertical direction (axial direction), and a through hole  4 B penetrating in the vertical direction (axial direction) is formed at the center portion. A protruding portion  4 C extending upward in the vertical direction (axial direction) is formed at the center portion of the yoke  4 . The protruding portion  4 C has a shape having an inclined portion in which a radially central side is high and a radially outer side is low when viewed in a cross section. 
     A cylindrical member  6  of a non-magnetic body is fixedly arranged so as to lie along the radially outer side (outer periphery) of the protruding portion  4 C on an upper surface of the bottom portion  4 D of the yoke  4 . 
     The cylindrical member  6  is formed in a substantially cylindrical shape. The outer diameter of the cylindrical member  6  is formed in a stepped form, and includes a small outer diameter portion  6 E in which a diameter on the upper side in the vertical direction (axial direction) is formed small, and a large outer diameter portion  6 F in which a diameter on the lower side in the vertical direction (axial direction) is formed large. The inner diameter of the cylindrical member  6  includes, from the upper side in the axial direction, an upper large diameter portion  6 A having a large diameter, a small diameter portion  6 B formed by reducing the diameter in a stepped form from the upper large diameter portion  6 A, a diameter enlarged portion  6 C in which the diameter expands in a tapered form from the small diameter portion  6 B, and a lower large diameter portion  6 D connected to the diameter enlarged portion  6 C. The lower large diameter portion  6 D is fitted to the radially outer side (outer periphery) of the protruding portion  4 C of the yoke  4 . The diameter enlarged portion  6 C is formed so as to face the inclined portion of the protruding portion  4   c  of the yoke  4 . 
     With the above configuration, in the third example, effects similar to those of the first example can be obtained, and the protruding portion  8 C of the yoke  4  can have a thicker thickness, so that deformation of the protruding portion  8 C at the time of press-fitting or brazing can be suppressed. Furthermore, in the third example, deformation when the fluid pressure is generated can also be suppressed. 
     In the first to third examples, the yoke  4  and the anchor  8  are configured as separate bodies, but the yoke  4  and the anchor  8  may be integrally configured. In this case, the protruding portion  4 C and the protruding portion  8 C are integrally configured. 
     Note that the present invention is not limited to the examples described above, and includes various modifications. For example, the examples described above have been described in detail for the sake of easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. 
     REFERENCE SIGNS LIST 
       1  solenoid coil 
       2  bobbin 
       2 A recessed portion 
       3  resin 
       4  yoke 
       5  upper core 
       6  cylindrical member 
       6 F 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  reservoir 
       85  damping force generation means 
       87  main valve unit 
       88  pilot valve unit