JP4836743B2 - Seal structure of sliding part - Google Patents

Description

  The present invention relates to a seal structure for a sliding portion.

  The seal structure of this kind of sliding part can be seen, for example, in a hydraulic shock absorber provided with a cylindrical gas spring on the outer peripheral side. As an example of such a hydraulic shock absorber, the outer peripheral portion of the hydraulic shock absorber is an inner wall of a gas spring, and the outer wall of the gas spring is an air piston attached to a cylinder of the hydraulic shock absorber, and a piston rod of the hydraulic shock absorber. An air chamber attached to the front end of the cylinder and a diaphragm connecting the air piston and the air chamber, and a seal structure of a sliding portion is applied between the cylinder of the hydraulic shock absorber and the piston rod.

  Specifically, such a seal structure of the sliding portion is integrated with the inner peripheral side of the annular rod guide fixed to the inner peripheral side of the cylinder or the inner peripheral side of the annular insert metal. An oil seal is provided, and a sliding portion between the piston rod and the rod guide integrated with the cylinder is sealed by the oil seal.

When the inner wall of the gas spring is formed on the outer periphery of such a hydraulic shock absorber, the pressure in the cylinder of the hydraulic shock absorber is higher than the atmospheric pressure, and the pressure in the gas spring is also about the atmospheric pressure. Since there is no difference, generally, the seal structure of the sliding portion in the hydraulic shock absorber adopts the same configuration as that of the hydraulic shock absorber that does not have a gas spring (for example, Patent Documents). 1).
Japanese Patent Laying-Open No. 2003-42215 (FIG. 1)

  In the case of a hydraulic shock absorber, as described above, the seal between the piston rod and the cylinder can adopt a general seal structure similar to that of a hydraulic shock absorber that does not include a gas spring. When the shock absorber is an electromagnetic shock absorber having a different operating principle, there are problems in the following points.

  Here, the electromagnetic shock absorber includes, for example, a motion conversion mechanism that converts linear motion to rotational motion, such as a feed screw mechanism, and a motor to which the rotational motion is transmitted, as seen in JP-A-2005-140144. When the gas spring is formed in the electromagnetic shock absorber, the outer wall of the gas spring becomes a hollow shaft member connected to the motor side and a linear motion member that exhibits linear motion among the motion conversion mechanisms. The cylinder member is connected to the ball screw nut side, and the sliding portion between the shaft member and the cylinder member is sealed.

  When a cylindrical gas spring is formed on the outer periphery of the electromagnetic shock absorber, the inner wall of the gas spring is referred to as the shaft member and the cylinder member, and in any case, between the shaft member and the cylinder member. It is necessary to seal.

  As described above, since the electromagnetic shock absorber uses the torque generated by the motor as the damping force generation source, regardless of whether the gas spring is installed inside the shock absorber or outside the shock absorber, the shaft Since the high pressure in the gas spring acts on one side of the seal provided between the member and the cylindrical member, and the atmospheric pressure acts on the other side, in order to maintain the gas spring inside in a sealed state, It is necessary to increase the tension of the seal.

  In addition, in the case of an electromagnetic shock absorber, the diameter of the shaft member and the cylinder member does not contain liquid such as hydraulic oil and the motion conversion mechanism is housed inside the shaft member or the cylinder member. Therefore, when the gap between the shaft member and the cylindrical member of such an electromagnetic shock absorber is sealed, the sliding resistance is large, and the smooth expansion and contraction of the electromagnetic shock absorber is significantly hindered.

  Therefore, the present invention has been made in consideration of the above-mentioned problems, and the object of the present invention is to prevent pressure leakage of the gas spring while ensuring smooth movement between the shaft member and the cylindrical member. It is possible to provide a seal structure for a sliding portion.

In order to achieve the above-described object, a gas chamber is provided between the cylindrical member and the shaft member that is movably inserted into the cylindrical member, or provided outside the cylindrical member or between the shaft member and the cylindrical member. In the seal structure of the sliding portion to be sealed, the first seal member and the second seal member are arranged in series between the cylindrical member and the shaft member, and the first seal member and the second seal member A bearing that slides on the outer periphery of the shaft member and a chamber chamber in which lubricating liquid is sealed are provided between the chamber and the chamber, and a gas having a pressure lower than the pressure of the gas chamber but higher than the atmospheric pressure is sealed in the chamber chamber. It is characterized by being made.

According to the seal structure of this sliding portion, even if the tightening force of the first seal member and the second seal member is set smaller than when sealing with one seal member, gas leakage in the gas chamber is prevented. It is possible to prevent .
In addition, since the bearing is provided in the vicinity of the chamber chamber, it becomes possible to simultaneously lubricate the bearing with the lubricating liquid in the chamber chamber, and in this way, the cylindrical member and the shaft member can be smoothly moved. This makes it possible to prevent pressure leakage in the gas chamber while ensuring the above.

  And since it becomes possible to prevent pressure leakage in the gas chamber while ensuring smooth movement between the cylindrical member and the shaft member, it is inevitable that the diameter of the cylindrical member and the shaft member becomes large. Suitable for the seal part.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a seal structure of a sliding portion in one embodiment. FIG. 2 is a vertical cross-sectional view of an electromagnetic shock absorber to which a sliding portion seal structure according to an embodiment is applied.

As shown in FIG. 1, the seal structure S of the sliding part in one embodiment is provided between the cylindrical member 1 and a shaft member 2 that is movably inserted into the cylindrical member 1. A first seal member 3 and a second seal member 4 provided in series between the cylindrical member 1 and the shaft member 2, and provided between the first seal member 3 and the second seal member 4. A bearing 8 and a chamber chamber 5 are provided.

  On the other hand, as shown in FIG. 2, the electromagnetic shock absorber D to which the sliding portion seal structure S is applied is converted by a motion conversion mechanism H that converts linear motion into rotational motion, and the motion conversion mechanism H. And a motor M to which the rotational motion is transmitted. Further, on the outer peripheral side of the electromagnetic shock absorber D, there is a ball screw nut 10 that is a linear motion member that exhibits a linear motion of the motor M and the motion conversion mechanism H. A gas spring A is provided as a gas chamber interposed therebetween.

  In the following, the motion conversion mechanism H will be described in detail. In this embodiment, the motion conversion mechanism H is a screw shaft 11 as a rotating member that exhibits a rotational motion, and a linear motion member that is rotatably engaged with the screw shaft 11 and exhibits a linear motion. And a ball screw nut 10 constitute a feed screw mechanism.

  The screw shaft 11 is coupled to the rotor R of the motor M, and the ball screw nut 10 can be linearly moved by rotating the screw shaft 11 by driving the rotor R of the motor M. Further, the ball screw nut 10 is linearly moved by an external force, whereby the screw shaft 11 is rotated, and the rotor R of the motor M can be forcibly driven by an external force.

  Therefore, in this electromagnetic shock absorber D, the ball screw nut 10 is linearly moved in the vertical direction in FIG. 2 by rotating the screw shaft 11 with the torque generated by the motor M by supplying electric power to the motor M. Can function as an actuator, and when the ball screw nut 10 is forcibly linearly moved by an external force, the rotor R of the motor M exhibits a rotational motion, and the motor M is caused by an induced electromotive force. Since the torque that suppresses the rotational movement of the rotor R is generated, it functions to suppress the linear movement of the ball screw nut 10. That is, in this case, the linear motion of the member on the linear motion side is suppressed by the regenerative torque generated by the motor M regenerating the kinetic energy input from the outside and converting it into electrical energy.

  That is, the electromagnetic shock absorber D can apply a thrust to the ball screw nut 10 by positively generating a torque in the motor M, and the ball screw nut 10 can be forced to linearly move by an external force. Therefore, the linear motion of the ball screw nut 10 can be suppressed by the regenerative torque generated by the motor M.

  Therefore, the electromagnetic shock absorber D not only generates a damping force that suppresses the linear motion of the screw shaft 1 but also functions as an actuator. Therefore, the electromagnetic shock absorber D functions as a vehicle body. When used by being interposed between the axles, for example, the posture control of the vehicle body can also be performed simultaneously, thereby functioning as an active suspension.

  In addition to the above, the motion conversion mechanism H may be configured by a mechanism such as a rack and pinion or a worm gear.

  Further, even if the rotating member connected to the rotor R of the motor M is the ball screw nut 10 and the screw shaft 11 is a linear motion member, it can function as the electromagnetic shock absorber D as described above. .

  Further, as shown in FIG. 2, the gas spring A is connected to the cylindrical member 1 connected to the lower end of the linkage cylinder 12 that holds the ball screw nut 10, the casing of the motor M, and the screw shaft 11 and the ball screw. A hollow shaft member 2 that covers the outside of the nut 10 and is movably inserted into the cylindrical member 1, an air chamber 13 that is connected to the motor M, and a base end on the outer peripheral side of the cylindrical member 1. A substantially hollow conical air piston 14 that is coupled and covers the cylindrical member 1, and a diaphragm 15 that is fixed to the lower end of the air chamber 13 in FIG. 2 and the upper end of the air piston 14 in FIG. 2. In this case, the inner wall of the gas spring A is formed by the cylindrical member 1 and the shaft member 2.

  As is apparent from the above description, in this document, the connection includes not only the case where the members are directly connected but also the case where the members are connected via separate members.

  The screw shaft 11 is rotatably held by a bearing 16 provided on the inner periphery of the upper end of the shaft member 2 and is accommodated in the shaft member 2, and the motor M is connected to a vehicle body side member of a vehicle (not shown). As a result, it is connected to the vehicle body side member. On the other hand, the ball screw nut 10 is held by a link cylinder 12 whose lower end is connected to the cylinder member 2 and is connected to the axle side member of the vehicle via an eye E provided at the lower end of the cylinder member 1. ing.

  Next, the seal structure S that seals the space between the tubular member 1 and the shaft member 2 will be described. This seal structure S is attached to the upper end opening 1a of the tubular member 1 in FIGS. It is embodied in an inner peripheral portion of a cylindrical seal case 6 through which the shaft member 2 is inserted.

  As shown in FIG. 1, the seal case 6 includes a cylindrical case body 7 fitted in the opening 1 a of the cylindrical member 1, and a partition member 8 that defines a chamber chamber 5 on the inner periphery of the case body 7. 2 and a cap 9 that closes the upper end of the case main body 7 in FIG. 2 and forms an accommodating portion in which the first seal member 3 is accommodated between the partition member 8 and the cap 9.

  The case main body 7 is formed in a bottomed cylindrical shape, and a hole 7 b is provided in the bottom portion 7 a so that the shaft member 2 can be inserted, and an outer periphery of the bottom portion 7 a is formed on an inner periphery of the opening portion 1 a of the cylindrical member 1. It is press-fitted and fitted. Further, a concave portion 7c is formed on the inner peripheral side of the bottom portion 7a so that the second seal member 4 can be accommodated, and the second seal member 4 is provided on the upper end side in FIG. 1 of the concave portion 7c. The snap ring 20 prevents the recess 7c from falling off.

  Further, an annular partition member 8 is fitted to the upper end in FIG. 1 of the cylindrical portion 7d rising from the bottom portion 7a of the case body 7, and this partition member 8 is in the vertical direction in FIG. The length is set to be shorter than the length in the vertical direction in FIG. 1 of the cylindrical portion 7d, and a flange 8a provided on the outer periphery of the upper end abuts on the upper end of the cylindrical portion 7d so as to inward the case body 7 of the partition member 8. Movement is restricted.

  1 is partitioned by the lower end in FIG. 1 of the partition member 8, the cylindrical portion 7 d and the bottom portion 7 a of the case main body 7, and the shaft member 2 inserted into the seal case 6. A chamber chamber 5 is formed.

  In addition, a bearing 8b that is in sliding contact with the outer periphery of the shaft member 2 is provided on the inner periphery of the partition member 8, so that the shaft of the cylindrical member 1 and the shaft member 2 to which the seal case 6 is attached does not shake. ing. An annular groove 8c is formed on the outer periphery of the partition member 8, and an O-ring 8d accommodated in the annular groove 8c is brought into contact with the inner periphery of the cylindrical portion 7d of the case body 7 in a compressed state. The space between the partition member 8 and the case body 7 is sealed.

  Furthermore, a recess 8e is provided on the upper end side of the partition member 8, and the first seal member 3 is accommodated in the recess 8e.

  And the cap 9 is provided with the cylinder part 9a and the top part 9b, and while the hole 9c which accept | permits the insertion of the shaft member 2 is provided in the top part 9b, the screw part provided in the inner periphery of the cylinder part 9a 9d is screwed into a screw portion 7e provided on the outer periphery of the upper end of the cylindrical portion 7d of the case main body 7, so that the case main body 7 is integrated.

  The partition member 8 is fixed to the case body 7 by sandwiching the flange 8 a of the partition member 8 between the cap 9 and the upper end of the cylindrical portion 7 d of the case body 7.

  Next, the first seal member 3 is annular, and is accommodated between the cap 9 and the partition member 8 in the present embodiment at a position facing the gas spring A so as to seal the high pressure side, A dust seal portion 3a that is in sliding contact with the outer periphery of the shaft member 2 is provided on the upper side in FIG. 1 that is the gas spring A side, and a gas spring that is in sliding contact with the outer periphery of the shaft member 2 on the lower side in FIG. A main seal portion 3b for preventing gas leakage in A, and a ring 3c that presses the main seal portion 3b toward the shaft member 2 side, the outer peripheral side of which is in contact with the side surface of the recess 8e of the partition member 8 It is. The first seal member 3 is provided with a mandrel 3d inside to prevent deformation of the whole and maintain good sealing performance.

  The second seal member 4 is accommodated in a recess 7c of the case body 7 facing the chamber chamber 5, and is formed in an annular shape, and has an inner peripheral seal portion 4b that is in sliding contact with the outer periphery of the shaft member 2 with the recess 4a as a boundary. The ring 4c that presses the inner peripheral seal portion 4b toward the shaft member 2 and the outer peripheral seal portion 4d that comes into contact with the side surface of the concave portion 7c of the case body 7 are formed in a substantially U-packing shape, and the concave portion 4a The pressure on the chamber chamber 5 side can be received by the concave portion 4a with the surface facing the chamber chamber 5 side. Even in the second seal member 4, a mandrel 4e is provided inside to prevent the entire deformation and maintain a good sealing property.

  In the chamber 5, oil is used to reduce sliding friction between the first seal member 3 and the outer periphery of the shaft member 2 and between the second seal member 4 and the outer periphery of the shaft member 2. In addition, a high-pressure gas G is enclosed, and the pressure in the chamber 5 is lower than the pressure in the gas spring A but higher than the atmospheric pressure. In addition to the oil, the lubricating liquid L sealed in the chamber 5 is between the first seal member 3 and the outer periphery of the shaft member 2 and between the second seal member 4 and the outer periphery of the shaft member 2. The thing which can implement | achieve reduction of sliding friction can be used.

  The above-described seal case 6 is separate from the cylindrical member 1, but the same configuration as the seal case 6 may be provided directly on the inner peripheral side of the cylindrical member 1.

  In the seal structure S configured as described above, the pressure in the chamber chamber 5 on the back side of the first seal member 3 facing the gas spring A side is set higher than the atmospheric pressure. Compared to the structure in which the space between the gas spring A and the outside is sealed with a seal member, it is not necessary to set the tightening force higher than necessary, for example, by increasing the tightening allowance of the main seal portion 3b. Since the first seal member 3 only needs to have pressure resistance performance corresponding to the pressure difference between the pressure in the gas spring A and the pressure in the chamber chamber 5, it is not necessary to employ a special seal member. Since the seal member used for a simple hydraulic shock absorber can be used, the first seal member 3 is inexpensive.

  Furthermore, since it is possible to make the tension force smaller than when sealing with one seal member, it is possible to reduce the sliding resistance between the first seal member 3 and the shaft member 2, Even in this way, it is possible to prevent the gas in the gas spring A from leaking.

  Even in the second seal member 4, the chamber chamber 5 is set to be higher than the atmospheric pressure on the back side of the second seal member 4. It is not necessary to set the tightening force higher than necessary by setting the tightening margin of the inner peripheral seal portion 4b in the second seal member 4 more than necessary, as compared to the structure that seals between the two, Since the seal member 4 of 2 only needs to have a pressure resistance performance corresponding to the pressure difference between the pressure in the chamber chamber 5 and the atmospheric pressure, it is not necessary to employ a special seal member, and a general hydraulic shock absorber Therefore, the second seal member 4 is also inexpensive.

  Furthermore, since it is possible to make the tension force smaller than when sealing with one seal member, it is possible to reduce the sliding resistance between the second seal member 4 and the shaft member 2, Even in this case, it is possible to prevent the gas in the gas spring A from leaking through the chamber 5.

  Note that the second seal member 4 has a U-packing shape and receives the internal pressure of the chamber chamber 5 by the recess 4a. Therefore, the gas in the gas spring A temporarily passes through the main seal 3b. Even if it leaks into the chamber chamber 5, the pressure in the chamber chamber 5 rises accordingly, so that the inner peripheral seal portion 4 b is pressed against the shaft member 2 in accordance with the pressure rise, Gas leakage in the gas spring A can be reliably prevented.

  In addition, as described above, the cylindrical member 1 is connected to the ball screw nut 10 and the shaft member 2 is connected to the motor M. Therefore, the cylindrical member 1 and the shaft member 2 are connected to the electromagnetic shock absorber D. As the cylinder member 1 and the shaft member 2 move relative to each other, the lubricating liquid L in the chamber chamber 5 is applied to the outer periphery of the shaft member 2. Therefore, a film of the lubricating liquid L can be interposed between the first seal member 3 and the shaft member 2 and between the second seal member 4 and the shaft member 2. Thus, the sliding resistance at the seal portion when the cylindrical member 1 and the shaft member 2 are moved relative to each other can be reduced, and the smooth relative movement between the cylindrical member 1 and the shaft member 2 is ensured. In, smooth expansion and contraction of the electromagnetic shock absorber D is guaranteed.

  Furthermore, the cylinder member 1 and the shaft member 2 do not move relative to each other over a long period of time, and it is assumed that the space between the first seal member 3 and the shaft member 2 and between the second seal member 4 and the shaft member 2 are temporary. The chamber chamber 5 in which the lubricating liquid L is sealed is provided between the first seal member 3 and the second seal member 4 even when the film of the lubricating liquid L is interrupted. Therefore, even if the cylinder member 1 and the shaft member 2 move relative to each other in any direction, the first seal member 3 and the second seal member 4 are always between the shaft member 2 after the movement. Since a film of the lubricating liquid L is formed, a situation in which the sliding resistance of both the first seal member 3 and the second seal member 4 remains large is avoided. Between both the first seal member 3 and the second seal member 4 and the shaft member 2 when the shaft member 2 reciprocates simultaneously. It is possible to increase the opportunities to form a film of lubricating liquid L.

In particular, in the present invention, since the bearing 8b for guiding the shaft member 2 is provided in the vicinity of the chamber chamber 5, the lubrication between the bearing 8b and the shaft member 2 can be performed simultaneously. This is advantageous in that smooth relative movement between the tubular member 1 and the shaft member 2 can be ensured.

  Furthermore, since the gas G in addition to the lubricating liquid L is sealed in the chamber 5, the chamber is sealed by the continued expansion and contraction of the cylindrical member 1 and the shaft member 2 and the temperature change of the atmosphere. Even if the volume of the lubricating liquid L in the chamber 5 changes, the volume change of the lubricating liquid L is compensated by the volume change of the gas G, so that the pressure in the chamber chamber 5 becomes abnormally high and the chamber A situation in which the lubricating liquid L leaks excessively from the chamber 5 or the pressure in the chamber chamber 5 becomes equal to or lower than the atmospheric pressure, and the gas in the gas spring A or the gas is sucked into the chamber chamber 5 from the atmospheric pressure side. Is prevented, and a situation in which the seal case 6, the cylindrical member 1 or the shaft member 2 is deformed by the volume expansion due to the temperature rise of the lubricating liquid L is also prevented.

  Therefore, the seal structure S of the sliding portion is applied to a sealing portion of the sliding portion where the diameters of the cylindrical member 1 and the shaft member 2 are inevitably large, like the electromagnetic shock absorber D. However, even if the tightening force of the first seal member 3 and the second seal member 4 is set smaller than when the seal force is sealed with one seal member, the gas spring A can be prevented from leaking gas. In addition to this, the lubricating effect of the lubricating liquid L in the chamber chamber 5 prevents the pressure leakage in the gas chamber such as the gas spring A while ensuring smooth movement between the cylindrical member 1 and the shaft member 2. Is possible.

  Of course, the structure and shape of the first seal member 3 and the second seal member 4 can be changed as long as leakage of gas in the gas spring A as a gas chamber can be prevented.

  Further, in the above description, the electromagnetic shock absorber D is described as an example. However, between the cylinder as a cylinder member and the piston rod as a shaft member in an air damper having a gas chamber in which high-pressure gas is sealed. Even when the sliding portion is sealed, the same effect as described above can be obtained by applying the sealing structure S of the sliding portion.

  Further, in the above description, the first seal member 3, the second seal member 4, and the chamber chamber 5 are configured to face the outer periphery of the shaft member 2. On the contrary, The first seal member 3, the second seal member 4, and the chamber chamber 5 are configured such that the seal member 3, the second seal member 4, the chamber chamber 5, and the seal case 6 are completely opposite to the inner peripheral side and the outer peripheral side. Even if it is configured to face the inner periphery of the cylindrical member 1, the same effect as described above can be obtained. In this case, the seal case 6 configured to be opposite to the inner peripheral side and the outer peripheral side is provided on the shaft member 2 side. Should be provided. Even in this case, the seal case 6 configured to be opposite to the inner peripheral side and the outer peripheral side is not separated from the shaft member 2, and the same configuration is provided directly on the outer peripheral side of the shaft member 2. It may be.

  Further, when the space formed by the cylindrical member 1 and the shaft member 2 of the electromagnetic shock absorber D is a gas spring A, that is, the outer wall of the gas spring A is formed by the cylindrical member 1 and the shaft member 2. In the case of forming the seal structure S, the arrangement of the first seal member 3 and the second seal member 4 is upside down with respect to the state shown in FIG. The direction of the seal member 4 may be set upside down with respect to the state shown in FIG.

  Further, the cylindrical member 1 may be attached to the motor M side, and conversely, the shaft member 2 may be connected to the ball screw nut 10 serving as the linear motion member in the motion conversion mechanism H via the linkage cylinder 12. Good.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view of the seal structure of the sliding part in one Embodiment. It is a longitudinal cross-sectional view of the electromagnetic shock absorber to which the seal structure of the sliding part in one embodiment was applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical member 1a Opening part 2 Shaft member 3 First seal member 3a Dust seal part 3b Main seal part 3c, 4c Ring 3d, 4e Mandrel 4 Second seal member 4a, 7c, 8e Recessed part 4b Inner circumference seal part 4d Outer circumference Seal portion 5 Chamber chamber 6 Seal case 7 Case body 7a Bottom portion 7b, 9c Hole 7d, 9a Tube portion 7e, 9d Screw portion 8 Partition member 8a Flange 8b Bearing 8c Annular groove 8d O-ring 9 Cap 9b Top portion 10 Ball screw nut 11 Screw Axis 12 Linking cylinder 13 Air chamber 14 Air piston 15 Diaphragm 16 Bearing 20 Snap ring A Gas spring D as gas chamber D Electromagnetic shock absorber E Eye G Gas H Motion conversion mechanism M Motor L Lubricating liquid R Rotor S Seal structure of sliding part

Claims (3)

Seal structure of a sliding portion that is provided between a cylindrical member and a shaft member that is movably inserted into the cylindrical member and seals a gas chamber provided outside the cylindrical member or between the shaft member and the cylindrical member. in, cylindrical member and between the shaft member first sealing member and the second and a sealing member while arranged in series, the first seal member and the shaft member between the second seal member A bearing that is in sliding contact with the outer periphery and a chamber chamber in which lubricating liquid is sealed are provided, and a gas having a pressure lower than the pressure of the gas chamber but higher than the atmospheric pressure is sealed in the chamber chamber. Seal structure of sliding part. An inner wall of a cylindrical gas spring disposed on the outer peripheral side of a shock absorber provided with a motion conversion mechanism that converts linear relative motion into rotational motion and a motor having a rotor to which the rotational motion is transmitted, and the motion conversion mechanism A linear member that exhibits linear motion and a cylindrical member that is coupled to one of the motors, and a linear member that exhibits linear motion of the motion conversion mechanism and a shaft member that is coupled to the other of the motors. The seal structure of the sliding part according to claim 1, wherein An outer wall of a gas spring provided in a shock absorber having a motion conversion mechanism for converting linear relative motion into rotational motion and a motor having a rotor to which the rotational motion is transmitted is directly connected to the linear motion of the motion conversion mechanism. 2. A cylindrical member coupled to one of a moving member and a motor, a linear member exhibiting a linear motion of the motion conversion mechanism, and a shaft member coupled to the other of the motors. The sliding part seal structure described in 1.

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