JP2016194314A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a rod seal from particles contained in working fluid in the inside while keeping lubricating performance of the rod seal.SOLUTION: A working fluid 4 is an electroviscous fluid containing particles which can vary viscosity of the fluid in accordance with variation of an electric field. A rod seal 8 includes communication passages 12 for guiding the working fluid 4 from a radial outer side into a lubricating space 11 in an inner side of the rod seal 8 in order to supply the working fluid 4 to a sliding portion with a piston rod 6 in a contraction stroke of the piston rod 6, a lower spring member 14 as an obstructive member which is provided in such a manner of partially blocking the communication passages 12 and restrains the particles in the working fluid 4 from flowing into the lubricating space 11 through the communication passages 12, and an annular check lip 15 positioned in an inner cylinder 2 and slidably abutted to an outer peripheral surface 6A of the piston rod 6. The check lip 15 allows the working fluid 4 to flow out of the lubricating space 11, and restrains the working fluid 4 from flowing into the lubricating space 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shock absorber that is mounted on a vehicle such as a four-wheeled vehicle and is suitably used for buffering vibration of the vehicle.

  Some shock absorbers provided in vehicles such as automobiles are constituted by a liquid containing particles that make the viscosity of the fluid variable according to a change in electric field or magnetic field as a working fluid filled therein. Moreover, the shock absorber has a rod seal that is located on the protruding end side of the piston rod and seals the working fluid between the cylinder and the piston rod (for example, see Patent Document 1). The rod seal is provided with an oil seal that prevents the internal working fluid from flowing out, and a dust seal that prevents foreign matter (contamination) from entering from the outside.

JP 2010-190443 A

  In the shock absorber described in Patent Document 1, although the rod seal can be protected from external foreign matters by the dust seal, there is a problem that the oil seal cannot be protected from particles contained in the internal working fluid.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to protect the rod seal from particles contained in the internal working fluid while maintaining the lubricity of the rod seal. Is to provide a shock absorber.

  In order to solve the above-described problems, a shock absorber according to the present invention includes a cylinder in which a working fluid is sealed, a piston slidably fitted in the cylinder, and one end connected to the piston in the cylinder. A piston rod having the other end projecting outward from the cylinder, a rod guide provided on the projecting end side of the piston rod in the cylinder, and a projecting end of the piston rod from the rod guide. A shock absorber comprising: a rod seal that is positioned on a side and is held by the cylinder and seals the working fluid between the cylinder and the piston rod. And a liquid containing particles that make the viscosity of the fluid variable according to the rod seal. In order to supply the working fluid to the sliding portion with the piston rod, a communication path for guiding the working fluid from the radially outer side to the lubrication space inside the rod seal, and a part of the communication path are provided. A baffle member that prevents the particles contained in the working fluid from flowing into the lubrication space through the communication path, and an annular check lip that is located in the cylinder and is in sliding contact with the outer peripheral surface of the piston rod. The check lip is configured to allow the working fluid to flow out of the lubrication space and to prevent the working fluid from flowing into the lubrication space.

  According to the present invention, it is possible to protect the rod seal from particles contained in the internal working fluid while maintaining the lubricity of the rod seal.

It is sectional drawing which shows the hydraulic shock absorber by embodiment of this invention. It is sectional drawing which expands and shows the II section in FIG. It is sectional drawing of the principal part expansion which shows operation | movement of the check lip in FIG. It is sectional drawing of the principal part expansion which looked at the state which the check lip contact | abutted to the stopper from the same position as FIG.

  Hereinafter, a shock absorber according to an embodiment of the present invention will be described in detail with reference to FIGS. In the present embodiment, the case where an electrorheological fluid is used as the working fluid is illustrated.

  In FIG. 1, a hydraulic shock absorber 1 constitutes a typical example of a shock absorber. The hydraulic shock absorber 1 includes an inner cylinder 2, an outer cylinder 3, a piston 5, a piston rod 6, a rod guide 7, and a rod seal 8.

  The inner cylinder 2 as a cylinder is provided coaxially in an outer cylinder 3 which will be described later, and one end (lower end) side of the inner cylinder 2 is connected to the bottom cap side of the outer cylinder 3 (both not shown). It is fitted and fixed via. A rod guide 7 which will be described later is fitted and attached to the end on the other end (upper end) side of the inner cylinder 2.

  An outer cylinder 3 that constitutes a cylinder together with the inner cylinder 2 is provided on the outer peripheral side of the inner cylinder 2. The outer cylinder 3 has a closed end where one end is closed by a bottom cap, and the other end is an open end. On the opening end (upper end) side of the outer cylinder 3, a caulking portion 3A is provided by bending inward in the radial direction, and the caulking portion 3A prevents an outer peripheral side of a disk-like body 9 of a rod seal 8 to be described later. Is held in a state.

  The working fluid 4 is enclosed with gas in the inner cylinder 2 and the outer cylinder 3. The working fluid 4 is configured as an electrorheological fluid including a base oil (base oil) made of, for example, silicon oil, and particles that are mixed in the base oil and change the viscosity of the fluid in accordance with a change in electric field. . Therefore, the working fluid 4 made of an electrorheological fluid changes the flow resistance (damping force) according to the applied voltage. In this case, for example, a voltage application device (not shown) for applying a voltage to the working fluid 4 is provided between the inner cylinder 2 and the outer cylinder 3.

  Here, an annular reservoir A is formed between the inner cylinder 2 and the outer cylinder 3, and gas is sealed in the reservoir A together with the working fluid 4 described above. This gas may be atmospheric pressure air or a compressed gas such as nitrogen gas. The gas in the reservoir A is compressed to compensate for the entry volume of the piston rod 6 when the piston rod 6 is contracted (contraction stroke).

  The piston 5 is slidably fitted in the inner cylinder 2. The piston 5 divides the inside of the inner cylinder 2 into two chambers of a bottom side oil chamber (not shown) and a rod side oil chamber B. The piston 5 is formed with a plurality of oil passages (not shown) capable of communicating the bottom side oil chamber and the rod side oil chamber B.

  Further, on the upper end surface of the piston 5, when the piston 5 is slid downward due to the reduction of the piston rod 6, a reduction side that generates a predetermined damping force by applying a resistance force to the oil liquid flowing through the oil passage. A disc valve (not shown) is provided. On the other hand, when the piston 5 slides upward due to the extension of the piston rod 6, the lower end surface of the piston 5 gives a resistance force to the oil liquid flowing through the oil passage and generates a predetermined damping force. A disc valve (not shown) is provided.

  The piston rod 6 is connected to the piston 5 at the lower end side which is one end side thereof. That is, the lower end side of the piston rod 6 is inserted into the inner cylinder 2 and is fixed to the center position of the piston 5. On the other hand, the upper end side that is the other end side of the piston rod 6 protrudes to the outside of the inner cylinder 2 and the outer cylinder 3 through the rod guide 7 and the like so as to be able to expand and contract. Further, a cylindrical seal body 10 of a rod seal 8 described later is in gas-liquid-tight sliding contact with the outer peripheral surface 6A of the piston rod 6.

  The rod guide 7 is provided on the upper end side, which is the protruding end side of the piston rod 6, of the inner cylinder 2 and the outer cylinder 3, and guides the piston rod 6. The rod guide 7 is formed in a stepped cylindrical shape, and is fixed by a caulking portion 3 </ b> A of the outer cylinder 3 in a state of being fitted to the upper ends of the inner cylinder 2 and the outer cylinder 3. Thereby, the rod guide 7 positions the upper part of the inner cylinder 2 and the outer cylinder 3 in the coaxial position. Further, when the rod guide 7 is fixed by pressing the disk-shaped body 9 of the rod seal 8 from the outside (upper side) by the caulking portion 3A provided on the outer cylinder 3 (so-called caulking and fixing), the rod guide 7 is inward ( It constitutes a support structure to be supported from the lower side.

  The rod guide 7 is formed in a predetermined shape using, for example, a metal material, a hard resin material, or the like. That is, the rod guide 7 is located on the upper side and is inserted into the inner peripheral side of the outer cylinder 3, and the rod guide 7 is positioned on the lower side of the large diameter part 7 A and on the inner peripheral side of the inner cylinder 2. A stepped cylindrical body is formed by the small diameter portion 7B to be inserted. A guide portion 7C for guiding the piston rod 6 so as to be slidable in the axial direction is provided on the inner peripheral side of the small diameter portion 7B. The guide portion 7C is formed as a bearing in which, for example, the inner peripheral surface of a metal cylinder is covered with a fluororesin (tetrafluoroethylene) or the like.

  The upper side of the large-diameter portion 7A facing the rod seal 8 in the axial direction (up and down) is a substantially flat upper surface portion 7D having an annular shape. An annular annular protrusion 7E is formed on the outer peripheral side of the upper surface portion 7D, and a plurality of communication paths 7F (only one is shown) are provided in the axial direction in the large diameter portion 7A at the position of the annular protrusion 7E. It is formed through. Thereby, the communication path 7F can communicate the reservoir A and an oil retaining chamber C described later.

  Next, the configuration and function of the rod seal 8 that is a characteristic part of the present embodiment will be described.

  The rod seal 8 is held on the upper end side of the outer cylinder 3 and seals between the outer cylinder 3 and the piston rod 6 so that the internal working fluid 4 does not flow out. Specifically, the rod seal 8 is disposed on the protruding end side of the piston rod 6 with respect to the rod guide 7, that is, on the upper side of the upper surface portion 7 </ b> D of the rod guide 7. It is held together with the guide 7 by the caulking portion 3A.

  The rod seal 8 has a cylindrical sealing body 10 to be described later in sliding contact with the outer peripheral surface 6A of the piston rod 6, so that the internal working fluid 4 does not flow out, and external dust, rainwater, etc. The space between the outer cylinder 3 and the piston rod 6 is sealed (sealed) so as not to flow in. The rod seal 8 includes a disk-like body 9, a cylindrical seal body 10, spring members 13 and 14, a check lip 15, and a stopper 16 which will be described later. Further, the rod seal 8 is composed of a metal portion made of a core metal 9A described later and a rubber (resin) portion provided so as to cover the core metal 9A.

  Here, the temperature environment in which the hydraulic shock absorber 1 is used covers a wide range from a low temperature to a high temperature. For example, it is assumed to be used from a low temperature environment of −40 ° C. to a high temperature environment of 100 ° C. Along with this, fluororesin that is stable in silicon oil constituting the working fluid 4 is used for the resin portion of the rod seal 8. Since this fluororubber is not cured with respect to silicon oil, it can follow the expansion and contraction operation of the piston rod 6 from room temperature to a high temperature environment, and can secure a sealing property. On the other hand, in a low temperature environment, the temperature becomes lower than the glass transition point of fluororubber (about −20 ° C. to −10 ° C.), so in order to avoid curing (loss of elasticity) in this low temperature environment, Hardness at normal temperature is set to 70-80 (durometer A). Accordingly, the elongation remains to some extent even in a low temperature environment, so that the rod seal 8 can follow the expansion / contraction operation of the piston rod 6 even in a low temperature environment below the glass transition point.

  Therefore, the fluoro rubber used for the resin portion of the rod seal 8 can maintain a hardness of 70 to 80 (durometer A) from room temperature to a high temperature environment even when immersed in silicon oil. Moreover, the fluororubber is a material that can secure an elongation of 60% or more in a low temperature environment. Thus, the rod seal 8 using fluororubber can maintain the sealing performance under the specification environment in the hydraulic shock absorber 1 using the electrorheological fluid as the working fluid 4.

  The fluororubber used for the resin portion of the rod seal 8 is an effective material for the silicon oil of the working fluid 4, and when a base oil other than silicon oil is used as the base oil of the working fluid 4, In consideration of compatibility with oil, a configuration using a material other than fluororubber may be used.

  As shown in FIG. 2, the disk-shaped body 9 is disposed on the radially outer side of the piston rod 6 and faces the upper surface portion 7 </ b> D of the rod guide 7. The disk-shaped body 9 is formed in a disk shape with a core metal 9A made of an annular metal plate as a core material.

  A lip seal 9 </ b> B is provided on the lower surface of the disk-like body 9 so as to be located at an intermediate portion in the radial direction of the disk-like body 9. The lip seal 9B extends from the lower surface of the disk-shaped body 9 so as to expand outward in the radial direction, and its tip (lower end) abuts on the upper surface portion 7D of the rod guide 7. Yes. Thereby, the lip seal 9B is disposed between the oil retaining chamber C and the reservoir A, and allows the working fluid 4 in the oil retaining chamber C to flow into the reservoir A through the communication path 7F of the rod guide 7. The flow in the opposite direction, that is, the gas and oil in the reservoir A is prevented from flowing to the oil retaining chamber C side.

  An annular seal ring 9 </ b> C is integrally provided on the outer peripheral side of the disk-like body 9 by projecting downward from the lower surface. The seal ring 9 </ b> C prevents the gas in the reservoir A and the working fluid 4 from leaking outside between the outer cylinder 3 and the rod seal 8.

  The cylindrical seal body 10 is provided on the inner diameter side of the disk-shaped body 9 and is in sliding contact with the outer peripheral surface 6 </ b> A of the piston rod 6. The cylindrical seal body 10 includes an upper cylindrical portion 10A that protrudes upward on the outer side across the disc-like body 9 and a lower side that is opposite to the upper cylindrical portion 10A across the disc-like body 9. The projecting lower cylindrical portion 10B is formed as a stepped cylindrical body extending upward and downward. On the inner peripheral side of the upper cylindrical portion 10A that protrudes upward from the outer cylinder 3, an upper lip portion 10C that protrudes inward in the radial direction is provided. On the other hand, on the outer peripheral side of the upper cylindrical portion 10A, an upper fitting groove 10D having a semicircular cross section is provided over the entire circumference at a position corresponding to the upper lip portion 10C. The upper lip portion 10C is pressed against the outer peripheral surface 6A of the piston rod 6 by an upper spring member 13 (described later) fitted in the upper fitting groove 10D. It is a seal that works as a dust seal to prevent inflow.

  Next, a lower lip portion 10E is provided on the inner peripheral side of the lower cylindrical portion 10B extending downward so as to enter the outer cylinder 3 and projecting inward in the radial direction. The lower lip portion 10E is disposed at an intermediate portion in the axial direction (upper and lower direction) of the lower cylinder portion 10B, and has a cross-section half on the outer peripheral side of the lower cylinder portion 10B corresponding to the lower lip portion 10E. An arcuate lower fitting groove 10F is provided over the entire circumference. The lower lip portion 10E is pressed against the outer peripheral surface 6A of the piston rod 6 by a lower spring member 14 to be described later, which is fitted into the lower fitting groove 10F. It is a seal that works as an oil seal so that the working fluid 4 does not flow out.

  The lower end portion 10G of the lower cylindrical portion 10B is disposed with a space from the outer peripheral surface 6A of the piston rod 6, whereby the outer peripheral surface 6A of the piston rod 6 is interposed between the piston rod 6 and the cylindrical seal body 10. An annular lubricating space 11 is defined by the lower lip portion 10E and the lower end portion 10G. The lubricating space 11 is a space for storing the base oil in order to supply the base oil of the working fluid 4 to the sliding portion between the outer peripheral surface 6A of the piston rod 6 and the rod seal 8 as a lubricating oil. .

  The communication path 12 is provided in the lower cylindrical portion 10B of the cylindrical seal body 10 so as to penetrate in the radial direction. The communication path 12 is composed of, for example, a small radial hole that is formed in a plurality (only two are shown) at intervals in the circumferential direction. Each communication path 12 is fitted on the lower side so that the base oil (oil) passing through the lower spring member 14 to be described later and reaching the lower fitting groove 10F flows into the inner lubricating space 11 by its own weight. The groove 10 </ b> F extends inwardly from the groove bottom portion toward the lower side.

  Each communication path 12 guides the working fluid 4 to the lubricating space 11 when the working fluid 4 is substantially filled in the oil retaining chamber C during the reduction stroke of the piston rod 6. In this case, by functioning as a filter for removing particles contained in the working fluid 4 by the lower spring member 14 described later, only the oil liquid (base oil) suitable for lubrication can be guided to the lubrication space 11.

  The upper spring member 13 is called a spring band, for example, and is formed in a ring shape by connecting both ends of a long coil spring (tensile spring). The upper spring member 13 is fitted in the upper fitting groove 10 </ b> D of the cylindrical seal body 10 to urge the upper lip portion 10 </ b> C in the radial direction toward the outer peripheral surface 6 </ b> A of the piston rod 6. .

  The lower spring member 14 constitutes a baffle member that suppresses particles contained in the working fluid 4 from flowing into the lubricating space 11 through the communication passages 12. The lower spring member 14 is formed in a ring shape by connecting both ends of a long coil spring, like the above-described upper spring member 13. The lower spring member 14 is urged in the radial direction toward the outer peripheral surface 6A of the piston rod 6 by being fitted into the lower fitting groove 10F of the cylindrical seal body 10. It is.

  Here, the lower spring member 14 made of a coil spring is formed by winding a wire in a spiral shape, and the gap between adjacent wires has a small value. Therefore, the lower spring member 14 can partially close the opening on the outer peripheral side of each communication passage 12 by fitting into the lower fitting groove 10F of the cylindrical seal body 10. Thereby, the lower spring member 14 functions as a baffle member (filter), and particles contained in the working fluid 4 can be prevented from flowing into the lubricating space 11 through the communication passages 12.

  The check lip 15 is provided in the inner cylinder 2, that is, at the lower end portion 10 </ b> G of the cylindrical seal body 10 constituting the rod seal 8, and is in sliding contact with the outer peripheral surface 6 </ b> A of the piston rod 6. The check lip 15 is formed as an annular thin plate extending radially inward from the outer peripheral portion of the lower end portion 10G, and the inner end thereof is in sliding contact with the outer peripheral surface 6A of the piston rod 6.

  When the working fluid 4 is about to flow out of the lubrication space 11, the check lip 15 can bend downward to allow the working fluid 4 to flow out, as indicated by a two-dot chain line in FIG. On the other hand, when the working fluid 4 flows into the oil retaining chamber C during the reduction stroke of the piston rod 6 and this working fluid 4 tries to flow into the lubrication space 11, the check lip 15 is connected to the piston as shown in FIG. The gap between the outer peripheral surface 6 </ b> A of the rod 6 and the lower end portion 10 </ b> G of the cylindrical seal body 10 can be closed to prevent the working fluid 4 from flowing into the lubricating space 11.

  The stopper 16 is provided at a position in the vicinity of the check lip 15 of the rod seal 8, that is, at a lower portion on the inner peripheral side of the lower end portion 10G. The stopper 16 is formed as an abutment surface arranged with a predetermined interval dimension so that the check lip 15 abuts when the check lip 15 is displaced by a predetermined dimension in the valve closing direction (upward direction). . Thereby, even if the check lip 15 tends to be excessively deformed in the valve closing direction, the stopper 16 can restrict excessive deformation by bringing the check lip 15 into contact as shown in FIG. As a result, for example, it is possible to prevent a situation in which the check lip 15 enters the lubricating space 11 and cannot be opened.

  An annular oil retaining chamber C is provided between the piston rod 6, the rod guide 7, and the rod seal 8. The oil retaining chamber C temporarily accumulates the oil and the like that has flowed out when the oil or gas in the rod-side oil chamber B flows out through a slight gap between the piston rod 6 and the rod guide 7. Space for. Here, the oil that has flowed into the oil retaining chamber C can be returned to the reservoir A through the communication path 7F of the rod guide 7.

  The hydraulic shock absorber 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  The upper end side of the piston rod 6 is attached to the vehicle body side of the automobile, and the lower end side of the outer cylinder 3 is attached to the axle (not shown) side. As a result, when vibration is generated during driving of the automobile, when the piston rod 6 is contracted and expanded in the axial direction from the inner cylinder 2 and the outer cylinder 3, the disk 5 of the piston 5 is contracted and expanded by each disk valve. The damping force is generated and can be buffered so as to attenuate the upper and lower vibrations of the vehicle.

  Further, for example, a voltage application device provided between the inner cylinder 2 and the outer cylinder 3 is used, and a voltage is applied to the working fluid 4 from the voltage application device. Thereby, the working fluid 4 can change a flow resistance (damping force) according to the applied voltage, and can variably adjust the damping force.

  Thus, according to the present embodiment, the working fluid 4 is an electroviscous fluid containing particles that change the viscosity of the fluid in accordance with a change in the electric field, and the rod seal 8 has a reduction stroke of the piston rod 6. In order to supply the working fluid 4 to the sliding portion with the piston rod 6, each communication path 12 that leads the working fluid 4 from the radially outer side to the lubricating space 11 inside the rod seal 8, and each communication path 12 A lower spring member 14 serving as a baffle member that suppresses inflow of particles contained in the working fluid 4 provided in the working fluid 4 through the communication passages 12 into the lubricating space 11, and a position in the inner cylinder 2. An annular check lip 15 that is in sliding contact with the outer peripheral surface 6A of the piston rod 6 is provided. The check lip 15 allows the working fluid 4 to flow out of the lubricating space 11, and the working fluid 4 flows into the lubricating space 11. Suppress We are trying to be.

  Therefore, each communication passage 12 can guide the working fluid 4 to the lubricating space 11 in the rod seal 8 during the contraction stroke of the piston rod 6, and supplies the working fluid 4 to the sliding portion with the piston rod 6. Can do. In this case, since the lower spring member 14 is provided as a baffle member so as to partially block each communication passage 12, the lower spring member 14 removes particles contained in the working fluid 4 and is suitable for lubrication. Only the oil liquid (base oil) can be guided to the lubricating space 11.

  As a result, the lubricity of the rod seal 8 with respect to the piston rod 6 can be maintained by the oil liquid guided to the lubrication space 11. In addition, the rod seal 8 (lower lip portion 10E, etc.) can be protected from particles contained in the working fluid 4 inside the inner cylinder 2.

  Moreover, the check lip 15 provided on the rod seal 8 can allow the working fluid 4 to flow out of the lubricating space 11, and can prevent the working fluid 4 from flowing into the lubricating space 11. Thereby, even if the particles of the working fluid 4 flow into the lubricating space 11, the particles can be easily discharged by opening the check lip 15. Further, the check lip 15 can prevent the inflow of particles from the part where the particles are discharged.

  The rod seal 8 is disposed on the radially outer side of the piston rod 6, and is in contact with the rod guide 7. The rod seal 8 is provided on the inner diameter side of the disk-shaped body 9 and is in sliding contact with the outer peripheral surface 6 </ b> A of the piston rod 6. A cylindrical seal body 10 is used. The communication passage 12 is a small radial hole formed in the tubular seal body 10. On this, the baffle member is provided on the outer peripheral side of the cylindrical seal body 10 so as to partially block each communication path 12 formed of a small hole, and the cylindrical seal body 10 is connected to the outer peripheral surface 6A of the piston rod 6. It is comprised by the ring-shaped lower side spring member 14 urged | biased to radial direction toward.

  Thereby, the ring-shaped lower spring member 14 for urging the cylindrical seal body 10 toward the outer peripheral surface 6A of the piston rod 6 is used, and in this case, each communication path 12 is partially blocked. Since the lower spring member 14 is provided as a baffle member, the existing lower spring member 14 can be used as a filter for removing particles contained in the working fluid 4 and is suitable for lubrication with a simple configuration. Only the oil liquid (base oil) can be guided to the lubricating space 11.

  A stopper 16 that restricts excessive deformation of the check lip 15 is provided in the vicinity of the check lip 15 of the rod seal 8 by contacting the check lip 15 during the extension stroke of the piston rod 6. Thereby, even if the check lip 15 tends to deform excessively in the valve closing direction, the stopper 16 can restrict the excessive deformation of the check lip 15. As a result, the valve opening failure of the check lip 15 can be prevented, and the reliability can be improved.

  Furthermore, the working fluid 4 is configured as an electrorheological fluid. Thereby, by applying a voltage to the working fluid 4, the damping force can be variably adjusted according to the applied voltage.

  In the embodiment, the case where the working fluid 4 is configured as an electrorheological fluid including a base oil and particles that change the viscosity of the fluid according to a change in electric field is illustrated. However, the present invention is not limited to this. For example, the working fluid may be a magnetic fluid including a base oil and particles that change the viscosity of the fluid in accordance with changes in the magnetic field. In this case, for example, a magnetic field applying device for applying a magnetic field to the working fluid made of a magnetic fluid may be provided between the inner cylinder and the outer cylinder.

  In the embodiment, the hydraulic shock absorber 1 attached to each wheel side of the four-wheel automobile has been described as a typical example of the shock absorber. However, the present invention is not limited to this, and may be, for example, a hydraulic shock absorber used for a two-wheeled vehicle, or may be used for a shock absorber used for various machines other than cars, buildings, and the like.

1 Hydraulic shock absorber
2 Inner cylinder (cylinder)
3 Outer cylinder (cylinder)
4 Working fluid 5 Piston 6 Piston rod 6A Outer peripheral surface 7 Rod guide 8 Rod seal 9 Disc-shaped body 10 Tubular seal body 11 Lubrication space 12 Communication path 14 Lower spring member (baffle member)
15 Check lip 16 Stopper B Rod side oil chamber C Oil retention chamber

Claims (5)

A cylinder filled with a working fluid;
A piston slidably inserted into the cylinder;
A piston rod having one end connected to the piston in the cylinder and the other end protruding outward from the cylinder;
A rod guide that is provided on the protruding end side of the piston rod in the cylinder and guides the piston rod;
A rod seal which is positioned on the protruding end side of the piston rod with respect to the rod guide and held by the cylinder, and seals the working fluid between the cylinder and the piston rod;
In a shock absorber comprising:
The working fluid is composed of a liquid containing particles that change the viscosity of the fluid in response to a change in electric field or magnetic field,
For the rod seal,
A communication path for guiding the working fluid from a radially outer side to a lubricating space inside the rod seal in order to supply the working fluid to a sliding portion with the piston rod in a reduction stroke of the piston rod;
A baffle member that is provided so as to partially block the communication path and prevents the particles contained in the working fluid from flowing into the lubrication space through the communication path;
An annular check lip located in the cylinder and in sliding contact with the outer peripheral surface of the piston rod;
The shock absorber according to claim 1, wherein the check lip is configured to allow the working fluid to flow out of the lubrication space and to prevent the working fluid from flowing into the lubrication space. The rod seal includes a disk-shaped body disposed on the radially outer side of the piston rod and facing the rod guide, and a cylindrical seal provided on the inner diameter side of the disk-shaped body and in sliding contact with the outer peripheral surface of the piston rod. Composed of body and
The communication path includes a plurality of small holes in the radial direction formed in the cylindrical seal body,
The baffle member is provided on the outer peripheral side of the cylindrical seal portion so as to partially block the small holes, and is a ring shape that urges the cylindrical seal body in the radial direction toward the outer peripheral surface of the piston rod. The shock absorber according to claim 1, comprising a spring member.   3. The stopper according to claim 1, wherein a stopper that restricts excessive deformation of the check lip is provided at a position in the vicinity of the check lip of the rod seal by contacting the check lip during an extension stroke of the piston rod. The shock absorber described.   The shock absorber according to any one of claims 1 to 3, wherein the working fluid is an electrorheological fluid.   The shock absorber according to claim 1, wherein the working fluid is a magnetic fluid.

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