JP7116018B2 - Solenoid device and shock absorber using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a solenoid device that generates electromagnetic force and a shock absorber containing the same.

2. Description of the Related Art As a shock absorber installed between a vehicle body and a wheel, a damping force adjustment type hydraulic shock absorber having an electric actuator (solenoid device) for switching a damping force adjustment valve built in a piston rod is known.

As such a technique, for example, in claim 1 of Patent Document 1, "In a solenoid device in which a fixed core and a movable core are inserted into a bobbin on which a coil is wound, the fixed core is mounted on the inner circumference of the bobbin. A solenoid device is proposed in which a cylindrical magnetic sleeve is fitted so as to face the magnetic sleeve, and the fixed iron core is fitted in the magnetic sleeve.

JP-A-2002-139167

In the solenoid device of Patent Document 1, as shown in FIG. 2 of the same document, fluid flows from the cylinder upper chamber side to the coil side by arranging a seal on the outer peripheral surface of the piston bolt 20 corresponding to the fixed iron core. Therefore, if the shaft length of the solenoid is shortened while ensuring the sealing performance, it is difficult to secure the required magnetic path area, and the thrust becomes small, so there is a problem that miniaturization is difficult.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a solenoid device capable of suppressing an increase in axial length while ensuring necessary sealing performance and thrust.

In order to achieve the above object, the solenoid device of the present invention comprises: a bobbin wound with a coil; and a seal portion provided on the outer peripheral surface of the fixed core. An annular projecting portion is formed so as to face the outer peripheral surface of the movable iron core, and the seal portion is provided at an axial height overlapping with the projecting portion.

According to the solenoid device of the present invention, it is possible to suppress the expansion of the axial length while ensuring the necessary sealing performance and thrust.

1 is a cross-sectional view of a main part of a damping force adjustable hydraulic shock absorber according to Embodiment 1. FIG. 1 is an enlarged view of a solenoid device according to Example 1. FIG. FIG. 8 is an enlarged view of a solenoid device according to Example 2; FIG. 11 is an enlarged view of a solenoid device according to Example 3;

DETAILED DESCRIPTION OF THE INVENTION Embodiments of a solenoid device according to the present invention and a damping force adjustable hydraulic shock absorber (hereinafter simply referred to as "buffer") incorporating the same will be described below with reference to the drawings. In the following examples, the shock absorber of the present invention will be described by taking as an example a shock absorber installed between the vehicle body and the wheels of a vehicle, but the present invention is limited to the configurations shown in the following examples. However, it also includes various modifications and applications within the technical concept of the present invention.

Embodiment 1 FIG. 1 is a cross-sectional view of the principal parts of a shock absorber 1 according to Embodiment 1 of the present invention installed between a vehicle body and wheels. In the following description, the upward direction (upper side) and the downward direction (lower side) in FIG. Although the first embodiment is a single-tube type damping force adjustable hydraulic shock absorber, it can also be applied to a double-tube type damping force adjustable hydraulic shock absorber having a reservoir. Furthermore, when applied to a double-cylinder type damping force adjustable shock absorber comprising an inner cylinder and an outer cylinder, a solenoid device, a damping valve, etc. are provided on the outer peripheral side of the outer cylinder.

As shown in FIG. 1, a piston 3 is slidably inserted into the cylinder 2 . The piston 3 partitions the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B. A working fluid is sealed in the cylinder 2 . A shaft portion 6 of a piston bolt 5 is inserted through the shaft hole 4 of the piston 3 , and the piston 3 is provided on the piston bolt 5 . The piston bolt 5 is provided with a substantially cylindrical annular base portion 7 extending radially outward, and an annular wall portion 7A located in the upper portion of the annular base portion 7 receives the lower end portion of a substantially cylindrical case member 8. They are connected by a screw joint 10 . A piston bolt 5 having a piston 3 is connected with a piston rod 9 via a case member 8 . The piston bolt 5 is formed with a shaft hole 50 (common passage) that extends toward the tip side (downward) along the axial direction (vertical direction) and whose upper end opens at the center of the bottom surface of the annular base portion 7 .

2, the shaft hole 50 includes an axial passage 48 formed in the upper portion of the shaft hole 50 and having an open upper end, an axial passage 30 formed in the lower portion of the shaft hole 50, an axial passage 48 and an axial passage 49 that communicates between the directional passages 30 and 48 . The diameter (inner diameter) of the axial hole 50 is the largest in the axial passage 30 and decreases in order of the axial passage 48 and the axial passage 49 .

The lower end of the piston rod 9 is connected to the upper end of the case member 8 with a screw joint 11 . A nut 12 is screwed onto the lower end of the piston rod 9 , and by tightening the nut 12 against the upper end of the case member 8 , loosening of the threaded joint 11 is prevented. A small diameter portion 13 is formed at the lower end of the piston rod 9 . An O-ring 14 for sealing between the case member 8 and the piston rod 9 is mounted in an annular groove formed in the outer peripheral surface of the small diameter portion 13 . The upper part of the piston rod 9 extends outside the cylinder 2 . The piston 3 is provided with an extension side passage 15 whose one end (upper end) opens toward the cylinder upper chamber 2A, and a compression side passage 16 whose one end (lower end) opens toward the cylinder lower chamber 2B. An extension-side damping valve 17 that controls the flow of the working fluid in the extension-side passage 15 is provided at the lower end of the piston 3 . A compression side damping valve 18 that controls the flow of the working fluid in the compression side passage 16 is provided at the upper end of the piston 3 .

The extension side damping valve 17 includes an extension side main valve 20 seated on an annular seat portion 19 formed on the outer peripheral side of the lower end surface of the piston 3, a pilot case 22 fixed to the piston bolt 5 by a nut 21, and an extension side main valve 20. An extension side back pressure chamber 23 is formed between the rear surface of the side main valve 20 and the pilot case 22 . The pressure in the extension-side back pressure chamber 23 acts on the extension-side main valve 20 in the valve-closing direction. Between the nut 21 and the pilot case 22, a washer 24, a retainer 25, and a disc valve 26 are provided in this order from the bottom. The inner peripheral edge of the disc valve 26 is sandwiched between the inner peripheral edge of the pilot case 22 and the retainer 25 . The extension-side main valve 20 is a packing valve in which an annular seal portion 20A made of an elastic body contacts the inner peripheral surface of the pilot case 22 over the entire circumference.

The extension-side back pressure chamber 23 communicates with the cylinder lower chamber 2B via a passage 27 formed in the pilot case 22 and a disk valve 26 . The extension-side back pressure chamber 23 is constantly communicated with the cylinder lower chamber 2B via an orifice 26A formed in the disk valve 26. As shown in FIG. The disk valve 26 opens when the pressure in the extension-side back pressure chamber 23 reaches a predetermined pressure to relieve the pressure in the extension-side back pressure chamber 23 to the cylinder lower chamber 2B. The extension-side back pressure chamber 23 communicates with a radial passage 29 formed in the piston bolt 5 via a disk-shaped extension-side back pressure introducing valve 28 . The radial passage 29 communicates with an axial passage 30 (common passage) formed in the piston bolt 5 .

The extension-side back pressure introduction valve 28 is a check valve that allows the working fluid to flow only from the radial passage 29 to the extension-side back pressure chamber 23 . The extension-side back pressure introduction valve 28 is seated on an annular seat portion 31 formed on the upper surface of the pilot case 22 on the inner peripheral side of the passage 27 . The extension-side back pressure introduction valve 28 has an inner peripheral edge portion sandwiched between the inner peripheral edge portion of the pilot case 22 and the spacer 32 . The extension-side back pressure chamber 23 is communicated with the radial passage 29 via an orifice 28A formed in the extension-side back pressure introduction valve 28 by opening the extension-side back pressure introduction valve 28 .

The axial passage 30 communicates with a radial passage 33 (compression side discharge passage) formed in the piston bolt 5 . The radial passage 33 communicates with the extension side passage 15 via a compression side check valve 34 provided in the piston 3 . The radial passage 33 is always communicated with the extension side passage 15 via an orifice 34A formed in the compression side check valve 34 . The compression side check valve 34 only allows the working fluid to flow from the radial passage 33 to the extension side passage 15 .

The compression damping valve 18 is fixed between the compression side main valve 36 seated on the annular seat portion 35 formed on the outer peripheral side of the upper end surface of the piston 3 and the annular base portion 7 of the piston bolt 5 and the piston 3 . and a compression side back pressure chamber 38 formed between the back surface of the compression side main valve 36 and the pilot case 37 . The pressure in the compression side back pressure chamber 38 acts on the compression side main valve 36 in the valve closing direction. The compression side main valve 36 is a packing valve in which an annular seal portion 36A made of an elastic body contacts the inner peripheral surface of the pilot case 37 over the entire circumference.

The compression-side back pressure chamber 38 communicates with the cylinder upper chamber 2A via a passage 42 formed in the pilot case 37 and a disk valve 41 . The compression side back pressure chamber 38 is constantly communicated with the cylinder upper chamber 2A via an orifice 41A formed in the disc valve 41. As shown in FIG. The disk valve 41 opens when the pressure in the compression side back pressure chamber 38 reaches a predetermined pressure, and relieves the pressure in the compression side back pressure chamber 38 to the cylinder upper chamber 2A. The compression side back pressure chamber 38 is formed by a radial passage 44 formed in the piston bolt 5 via a disk type compression side back pressure introducing valve 43 and a circumferential groove 39 formed in the inner peripheral surface of the pilot case 37 . is communicated with. The radial passage 44 communicates with an axial passage 48 (common passage) of the piston bolt 5 .

The compression side back pressure introduction valve 43 is a check valve that allows the working fluid to flow only from the radial passage 44 to the compression side back pressure chamber 38 . The compression side back pressure introduction valve 43 is seated on an annular seat portion 45 formed on the inner peripheral side of the passage 42 on the lower surface of the pilot case 37 . The inner peripheral edge of the compression side back pressure introduction valve 43 is sandwiched between the inner peripheral edge of the pilot case 37 and the spacer 40 . The compression side back pressure chamber 38 is communicated with the radial passage 44 via an orifice 43A formed in the compression side back pressure introduction valve 43 by opening the compression side back pressure introduction valve 43 .

The axial passage 48 communicates with a radial passage 46 (elongation-side discharge passage) formed in the piston bolt 5 . The radial passage 46 communicates with the compression side passage 16 via an extension side check valve 47 provided in the piston 3 . The radial passage 46 is always communicated with the compression side passage 16 via an orifice 47A formed in the expansion side check valve 47 . The extension side check valve 47 only allows the working fluid to flow from the radial passage 46 to the compression side passage 16 .

The flow of working fluid in the shaft hole 50 (common passage) of the piston bolt 5 is controlled by a pilot valve. The pilot valve has a valve spool 51 (valve element) slidably fitted in the shaft hole 50 . The valve spool 51 has a solid shaft and constitutes a pilot valve together with the piston bolt 5 . The valve spool 51 includes a base portion 52 slidably fitted in the upper portion of the axial passage 48, in other words, a portion above the radial passage 44, and a tapered portion 53 located in the axial passage 48. a valve portion 54 that is continuous with the base portion 52, a tip portion 55 (fitting portion) positioned in the axial passage 30 when the pilot valve is closed, and a connection portion 56 that connects the tip portion 55 and the valve portion 54. and The diameter (outer diameter) of the valve spool 51 is the largest at the base portion 52, and decreases in the order of the valve portion 54, the tip portion 55, and the connecting portion 56. As shown in FIG. Also, the outer diameter of the valve portion 54 is larger than the inner diameter of the axial passage 49 .

The valve spool 51 is urged upward against the piston bolt 5 by a valve spring 59 interposed between the spring bearing portion 57 of the tip portion 55 and the spring bearing portion 58 of the piston bolt 5. An end surface of the base portion 52 abuts (is pressed against) a rod 72 of a solenoid device 71, which will be described later. When the control current to the solenoid device 71 used as an actuator for controlling the movement of the valve spool 51 is 0A (during failure), the tip portion 55 strokes the valve spool 51 in the valve opening direction (upward direction in FIG. 3). and is fitted into the axial passage 49 . As a result, a pair of orifices are formed between the distal end portion 55 and the axial passage 49 to communicate between the axial passages 30 , 48 .

An annular seat portion 63 on which the valve portion 54 of the valve spool 51 is seated is formed at the opening peripheral portion of the upper end of the axial passage 49 (on the side of the axial passage 48). A tapered seating surface 54A is formed on the outer peripheral edge of the lower end of the valve portion 54 (on the side of the connecting portion 56). When the seating surface 54A of the valve spool 51 is seated on the seat portion 63 formed in the shaft hole 50 of the piston bolt 5, that is, when the pilot valve is closed, the tip portion 55 of the valve spool 51 is substantially circular. , the inner pressure receiving surface of the seat portion 63 receives the pressure on the side of the axial passage 30, and the tapered portion 53 receives the pressure on the side of the axial passage 48 with the annular pressure receiving surface formed between the outer diameter of the base portion 52 and the seat portion 63. receive.

Here, as shown in the enlarged view of FIG. 2, the solenoid device 71 of this embodiment includes a case member 8, a rod 72, a fixed iron core 68 (anchor), an upper core 76, a guide 103, a housing 102, a bobbin 109, and , a coil 74 and the like, and a movable iron core 69 (plunger) that can move in the axial direction is coupled to the outer peripheral surface of the rod 72 .

A coil 74 is wound between the upper and lower flanges of the bobbin 109 . The bobbin 109 includes a substantially cylindrical case member 8 disposed on the outer peripheral side of the solenoid device 71 , a flat ring-shaped upper core 76 disposed on the upper portion, and a substantially cylindrical body disposed so as to surround the rod 72 . It is stored in a storage space surrounded by the guide 103 and the fixed iron core 68 and the like arranged at the bottom. When the coil 74 is energized, a magnetic path M indicated by broken lines in FIG. , a thrust is generated to move the rod 72 integrally in the axial direction.

As shown in the cross-sectional view of FIG. 2, the storage space formed by the upper core 76, the fixed iron core 68, etc. has the same height on the outer peripheral side and the inner peripheral side on the upper side, and is deeper than the outer peripheral side on the lower side. It has a substantially trapezoidal cross-sectional shape with the peripheral side facing downward. In order to form the storage space having such a cross-sectional shape, the lower surface of the upper core 76 that defines the upper shape of the storage space is flat, and the upper surface of the fixed iron core 68 that defines the lower shape of the storage space is flat. An inclined surface 68D that is higher on the outer peripheral side and lower on the inner peripheral side is provided on the outer peripheral side over the entire circumference. The upper portion of the bobbin 109 is flat and the lower portion thereof is provided with an inclined surface along the inclined surface 68D of the fixed iron core 68 so that the bobbin 109 can be accommodated in such a storage space.

More specifically, the fixed iron core 68 is arranged to contact the upper surface of the annular base 7, and as shown in FIG. It is a substantially cylindrical iron core having a substantially annular outer convex portion 68C on the outer peripheral side and a vertically communicating through hole 68E in the center. Further, on the outer peripheral side of the inner convex portion 68A, there is a projecting portion 68B (also referred to as an axial height changing portion) projecting upward. The protruding portion 68B is formed so that the inner peripheral side is higher and the outer peripheral side is lower, and the protruding portion 68B serves as the path of the magnetic path M toward the movable iron core 69. As shown in FIG. A groove 68F for disposing the seal 107 is formed in a circumferential shape on the outer peripheral surface of the outer convex portion 68C.

Above the fixed iron core 68, a non-magnetic cylindrical member 105 is arranged that fits with the outer periphery of the projecting portion 68B. This non-magnetic cylindrical member 105 has a hole diameter inside the cylinder that is large at the upper end side and the lower end side and smaller at the intermediate portion. A lower portion of the intermediate portion having a small hole diameter is formed with an inclined portion so that the diameter gradually widens so as to face the projecting portion 68B of the fixed iron core 68 .

A substantially cylindrical guide 103 is arranged above the non-magnetic cylindrical member 105 so as to fit with the inner periphery of the upper end of the non-magnetic cylindrical member 105 . The guide 103 has a large outer diameter portion extending from the upper end to the intermediate portion, and a small outer diameter portion having a small outer diameter at the lower end that fits with the inner circumference of the upper end of the non-magnetic cylindrical member 105 . formed in As a result, the lower surface of the guide 103 is arranged so as to contact the upper surface of the intermediate portion of the non-magnetic cylindrical member 105 .

A bush 106 is arranged in the through hole 68E of the fixed iron core 68, and the rod is supported via the bush 106 so as to be vertically movable (axial direction).

The movable iron core 69 is made of an iron-based magnetic material and has a substantially cylindrical shape. placed for movement.

The rod 72 is formed in a cylindrical shape and has an intra-rod passage 73 that penetrates (extends) through the rod 72 in the axial direction (vertical direction).

The bobbin 109 is arranged outside the guide 103 and the non-magnetic cylindrical member 105 and has a cylindrical shape with upper and lower flanges, and a coil 74 is wound between the upper and lower flanges. A resin 110 is molded on the outside of the coil 74 . A magnetic upper core 76 is installed on the upper side of the upper collar portion of the bobbin 109 .

A lead wire connected to the coil 74 is taken out from the upper portion of the bobbin 109, passes through the inside of the piston rod 9 via a connecting portion, and can be energized from the outside.

Above the rod 72 and the movable iron core 69, as shown in FIG. 1, a cylindrical housing 102 having a bottomed cylindrical hole with a space for them to stroke is arranged. 2, the outer diameter side of the housing 102 is fitted to the upper side of the guide 103 with a seal 108 interposed therebetween. Further, the inner peripheral side of the cylindrical hole of the housing 102 supports the rod 72 via a bushing 78 so as to be movable in the vertical direction (axial direction).

In the movable iron core 69, a magnetic field generated when the coil 74 is energized generates a magnetic flux flow (magnetic path M) as indicated by a broken line in the figure, and the movable iron core 69 is axially attracted to the fixed iron core 68. Thrust is generated. A space with a variable volume formed between the fixed core 68 and the movable core 69 is referred to as a suction space.

Here, in order to efficiently generate thrust in the movable iron core 69, the magnetic path M passing through the lower portion of the guide 103 must pass through the movable iron core 69 to the inner surface of the projecting portion 68B of the fixed iron core 68 and the upper surface of the inner convex portion 68A. need to reach In other words, it is necessary to suppress the generation of a magnetic path from the guide 103 to the fixed core 68 without passing through the movable core 69 . For this purpose, it is effective to provide a non-magnetic portion between the guide 103 and the fixed core 68. In this embodiment, the non-magnetic cylindrical member 105 sandwiched between the lower surface of the guide 103 and the projecting portion 68B of the fixed core 68 provides A non-magnetic portion was formed. What is necessary is the non-magnetic portion between the guide 103 and the fixed iron core 68, so if the guide 103 can be fixed to the upper core 76, for example, the non-magnetic cylindrical member 105 as a support member for the guide 103 can be omitted. , the air between the guide 103 and the fixed iron core 68 may function as a non-magnetic portion.

In addition, in order to efficiently generate thrust in the movable iron core 69, it is necessary to concentrate the magnetic flux passing through the movable iron core 69 also on the projecting portion 68B on the inner peripheral side of the fixed iron core 68. also requires a non-magnetic portion. In this embodiment, the non-magnetic cylindrical member 105 and the bobbin 109 provided on the outer peripheral side of the projecting portion 68B serve as the non-magnetic portion. On the other hand, it is necessary to arrange a seal 107 on the outer peripheral surface of the fixed core 68 so that the fluid in the cylinder upper chamber 2A does not flow into the coil 74 side. Therefore, in the fixed core 68 of the present embodiment, by providing the above-described inclined surface 68D, the axial length of the fixed core 68 is formed to be longer on the outer peripheral side and shorter on the inner peripheral side. By changing the length in the axial direction with this inclined surface 68D, the flow of the magnetic flux becomes smooth, and there is an effect that the movable iron core 69 can efficiently generate a thrust force.

Inside the through-hole 68E, the inside of the circumferential groove 104 formed on the lower surface of the fixed iron core 68, the inside of the circumferential groove 95 formed on the upper surface of the annular base portion 7 of the piston bolt 5, and the spool back pressure chamber 70 (chamber). ) is formed. The upper end of the valve spool 51 and the lower end of the rod 72 are in contact within the spool back pressure chamber 70 at the upper end (one side end) of the pilot valve. The spool back pressure chamber 70 communicates with the cylinder upper chamber 2A through the upper chamber side communication passage when the pilot valve is closed.

The upper chamber side communication passage is a passage (not shown) between the circumferential groove portion 104 and an annular space 120 formed between the inner side of the annular wall portion 7A and the outer peripheral side of the fixed iron core 68. The annular space 120 and the cylinder upper chamber 2A and an orifice passage 121 provided in the annular wall portion 7A.

A spool back pressure relief valve 81 (check valve), a retainer 82, a plate 83, a disk 84, a retainer 85, and a disk valve 41 are provided between the annular base portion 7 of the piston bolt 5 and the pilot case 37 in this order from the top. be done. The inner peripheral edge of the disc valve 41 is sandwiched between the inner peripheral edge of the pilot case 37 and the retainer 85 .

The spool back pressure relief valve 81 has an inner peripheral edge sandwiched between the retainer 82 and the inner peripheral edge of the annular base 7 of the piston bolt 5 , and an outer peripheral edge formed on the lower surface of the annular base 7 of the piston bolt 5 . The user is seated on the seat portion 88 . Also, the check valve lower chamber 89 (annular space) is used as a space for opening the spool back pressure relief valve 81 . The spool back pressure relief valve 81 is a check valve that allows only the working fluid to flow from the spool back pressure chamber 70 to the check valve lower chamber 89 .

The spool back pressure chamber 70 communicates with the cylinder lower chamber 2B via a lower chamber side communication passage (communication passage). This lower chamber-side communication passage includes a circumferential groove 94 formed inside the seat portion 88 on the lower surface of the annular base portion 7 of the piston bolt 5 and a circumferential groove 95 extending vertically through the annular base portion 7 of the piston bolt 5 . , 94 in communication therewith. As a result, the spool back pressure chamber 70 communicates with the check valve lower chamber 89 via the passage 96 , the circumferential groove 94 and the spool back pressure relief valve 81 . The spool back pressure chamber 70 , the circumferential groove 104 , the circumferential groove 95 , the passage 96 , and the circumferential groove 94 form a flow path through which the working fluid flows as the piston rod 9 moves. A spool back pressure relief valve 81 provided in the flow path serves as a valve for opening and closing the flow path.

The lower chamber-side communication passages are further formed in the upper surface of the plate 83 and extend radially outward from the inner peripheral surface of the plate 83 , and are formed in the lower surface of the plate 83 and extend radially outward from the inner peripheral surface of the plate 83 . A groove 92 extending outward, a passage 91 extending vertically through the plate 83 to communicate between the grooves 90 and 92, and a diameter of the piston bolt 5 formed in the outer peripheral surface of the shaft portion 6 of the piston bolt 5. It has a groove 93 that connects the directional passage 44 and the groove 92 . Thereby, the check valve lower chamber 89 communicates with the axial passage 48 via the groove 90 , the passage 91 , the groove 92 , the groove 93 and the radial passage 44 . The groove 93 is formed by processing the shaft portion 6 of the piston bolt 5 to have a width across flats.

Next, the flow of working fluid will be described with reference to FIG. During the compression stroke of the piston rod 9 (hereinafter referred to as "during the compression stroke"), the working fluid in the cylinder lower chamber 2B flows through the compression side passage 16 and the extension side check valve 47 before the compression side main valve 36 opens. orifice 47A, radial passage 46, axial passage 48, radial passage 44, compression side back pressure introduction valve 43, compression side back pressure chamber 38, passage 42 of pilot case 37, and orifice 41A of disk valve 41. and flows into the cylinder upper chamber 2A.

Then, the valve spool 51 (valve element) moves and the valve portion 54 is separated from the seat portion 63 . That is, when the pilot valve is opened, the working fluid in the cylinder lower chamber 2B flows through the compression side passage 16, the orifice 47A of the extension side check valve 47, the radial passage 46, the axial passage 48, the axial passage 49, It flows through the axial passage 30, the radial passage 33, the compression side check valve 34, and the extension side passage 15 to the cylinder upper chamber 2A. Here, by controlling the current supplied to the coil 74 of the solenoid device 71, the opening pressure of the pilot valve can be adjusted. At the same time, the pressure of the working fluid introduced from the compression side back pressure introduction valve 43 to the compression side back pressure chamber 38 is also adjusted, so the valve opening pressure of the compression side main valve 36 can be controlled. When the compression side main valve 36 opens, the working fluid also flows from the cylinder lower chamber 2B to the cylinder upper chamber 2A through the flow path passing through the compression side main valve 36 .

During the extension stroke of the piston rod 9 (hereinafter referred to as "during the extension stroke"), the working fluid in the cylinder upper chamber 2A flows through the extension side passage 15 and the compression side check valve 34 before the extension side main valve 20 opens. orifice 34A, radial passage 33, axial passage 30, radial passage 29, extension side back pressure introduction valve 28, extension side back pressure chamber 23, passage 27 of pilot case 22, and orifice 26A of disk valve 26. and flows into the cylinder lower chamber 2B.

Then, the valve spool 51 (valve element) moves and the valve portion 54 is separated from the seat portion 63 . That is, when the pilot valve is opened, the working fluid in the cylinder upper chamber 2A flows through the extension side passage 15, the orifice 34A of the compression side check valve 34, the radial passage 33, the axial passage 30, the axial passage 49, It flows through the axial passage 48, the radial passage 46, the extension side check valve 47, and the compression side passage 16 to the cylinder lower chamber 2B. Here, by controlling the current supplied to the coil 74 of the solenoid device 71, the opening pressure of the pilot valve can be adjusted. At the same time, the pressure of the working fluid introduced from the extension-side back pressure introduction valve 28 to the extension-side back pressure chamber 23 is also adjusted, so the opening pressure of the extension-side main valve 20 can be controlled. When the extension-side main valve 20 opens, the working fluid in the cylinder upper chamber 2A flows to the cylinder lower chamber 2B through the flow path passing through the extension-side main valve 20 as well.

Next, the inflow and outflow of the working fluid in the spool back pressure chamber 70 will be described. During the extension stroke, the working fluid in the cylinder upper chamber 2A flows through the upper chamber side communication passage into the spool back pressure chamber 70 (chamber). That is, the working fluid in the cylinder upper chamber 2</b>A flows into the spool back pressure chamber 70 through the orifice passage 121 . The working fluid that has flowed into the spool back pressure chamber 70 flows through the lower chamber side communication passage (communication passage) to the cylinder lower chamber 2B. That is, the working fluid that has flowed into the spool back pressure chamber 70 passes through the passage 96, the circumferential groove 94, the spool back pressure relief valve 81 (check valve), the check valve lower chamber 89, the groove 90, the passage 91, the groove 92, the groove 93, the radial passage 44, the axial passage 48, the radial passage 46, the orifice 47A of the extension side check valve 47, and the compression side passage 16 to the cylinder lower chamber 2B. Further, when the valve spool 51 moves upward, the working fluid generated along with the movement flows through the lower chamber side communication passage to the cylinder lower chamber 2B.

Since the spool back pressure relief valve 81 is kept closed during the contraction process, the spool back pressure chamber 70 communicates with the low-pressure cylinder upper chamber 2A through the upper chamber side communication passage. moves upward, the working fluid generated along with the movement is discharged to the cylinder lower chamber 2B through the upper chamber side communication passage.

As described above, in the solenoid device 71 of the first embodiment, the axial length of the fixed iron core 68 is made longer on the outer peripheral side and shorter on the inner peripheral side by the inclined surface 68D on the upper surface of the fixed iron core 68. is ensured and a necessary magnetic path is constructed, the axial length of the fixed iron core 68 is not lengthened, and the size of the solenoid device 71 can be reduced.

Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a partially enlarged view of a shock absorber according to Embodiment 2 of the present invention. In the second embodiment, mainly different parts from the first embodiment will be described. Parts common to those in Example 1 are denoted by the same designations and the same reference numerals.

3 showing the second embodiment, the shape of the bobbin 109 and the winding method of the coil 74 are different from those of the first embodiment.

As shown in FIG. 3, the bobbin 109 has a cylindrical shape with an upper flange and a lower lower flange.

The coil 74 is wound from the upper end of the cylindrical outer side of the bobbin 109 and is formed by repeating folding back at the bottom and top. is formed along the inclined surface 68D of .

As a result, a larger number of coils 74 can be wound with the same axial length, and a large thrust force can be generated. Also, if the same thrust is required, the size can be reduced.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a partially enlarged view of a shock absorber according to Embodiment 3 of the present invention. In the third embodiment, mainly the differences from the first embodiment will be mainly described. Parts common to those in Example 1 are denoted by the same designations and the same reference numerals.

4 showing the third embodiment, the shape of the bobbin 109, the winding method of the coil 74, and the shape of the fixed core 68 are different from those of the first embodiment.

The fixed iron core 68 has an inner projection 68A on the inside of the upper surface and an outer projection 68C on the outside of the upper surface when viewed in axial cross section, and has a cylindrical shape with a through hole 68E connecting the upper and lower parts at the center. The outer convex portion of the upper surface is different from the first embodiment in that the axial length changing portion 68G is formed stepwise on the inner peripheral side as well.

Also, the bobbin 109 has a cylindrical shape with upper and lower flanges, and the length of the lower flange is shorter than that of the upper flange.

The coil 74 is wound from the upper inside upper end of the bobbin 109 and is formed by repeating folding back at the bottom and top. , the portion protruding outside the length of the lower flange of the bobbin 109 is formed such that the folding position gradually moves upward.

With the configuration as described above, it is possible to wind more coils 74 than in the second embodiment, and to generate a large thrust. Also, if the thrust is the same, it is possible to have a short and small structure.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations.

1... Buffer,
2... Cylinder,
2A... Cylinder upper chamber,
2B... Cylinder lower chamber,
3... Piston,
5... Piston bolt,
8... case member,
9... Piston rod,
68... Fixed iron core,
69... Movable iron core,
70 Spool back pressure chamber,
71 ... Solenoid device (electric actuator),
74 ... coil,
81 ... spool back pressure relief valve (check valve),
105... non-magnetic cylindrical member,
107... seal,
109 bobbin

Claims (6)

A bobbin wound with a coil,
a fixed iron core forming a lower end surface of a storage space for storing the bobbin;
a movable core arranged to face one end surface of the fixed core and moving in the axial direction;
A solenoid device comprising a seal portion provided on the outer peripheral surface of the fixed core,
On the inner peripheral side of one end face of the fixed core, a substantially annular projecting portion having a shorter axial length on the outer peripheral side than on the inner peripheral side is formed so as to face the outer peripheral surface of the movable core,
The solenoid device according to claim 1, wherein the seal portion is provided at an axial position overlapping with the projection portion. 2. The solenoid device according to claim 1, further comprising a non-magnetic cylindrical member having an inner peripheral surface that engages with the projecting portion and faces the outer peripheral surface of the movable iron core. 3. The solenoid device according to claim 1, wherein a portion of said coil is provided at an axial position overlapping said projecting portion. The bobbin is
One side rim and the other side rim with the same length, and a coil wound between both rims,
One side and the other side with different lengths, with a coil wound between the two,
Or, having one side brim with a coil wound around the one side brim,
3. The solenoid device according to claim 1 or 2, characterized in that: The storage space includes a case member forming an outer peripheral surface of the storage space, a guide forming an inner peripheral surface of the storage space, an upper core forming an upper end surface of the storage space, and the fixed iron core. surrounded by
5. A magnetic path M passing through said case member, said upper core, said guide, said movable iron core and said fixed iron core in this order is formed when an electric current is passed through said coil. A solenoid device according to any one of the preceding claims. a cylinder in which the working fluid is sealed;
a piston that is inserted into the cylinder and partitions the inside of the cylinder into a cylinder one-side chamber and a cylinder other-side chamber;
a piston bolt comprising the piston;
a piston rod connected to the piston bolt and extending to the outside of the cylinder;
a valve mechanism having a flow path through which the working fluid flows by movement of the piston rod; and a valve that opens and closes the flow path;
A shock absorber, wherein the valve is a damping force adjustment valve whose opening and closing operation is adjusted by the solenoid device according to any one of claims 1 to 5.

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