JP2020034066A - Bump stopper and shock absorber - Google Patents

Abstract

To provide a bump stopper which can prevent cracking during attachment to an end part outer periphery of an outer tube and prevent falling from the outer tube, and to provide a shock absorber.SOLUTION: In order to achieve the object stated above, a bump stopper 1 of the invention is formed including: a cylinder part 2 which is fitted in an end part outer periphery of an outer tube 10 of a shock absorber D to elastically deform; and claws 3 which are provided at an inner periphery of the cylinder part 2 and entered into a groove 10a provided at an outer periphery of the outer tube 10 by elastic deformation of the cylinder part 2. A shock absorber D includes the bump stopper 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bump stopper and a shock absorber.

  Conventionally, a shock absorber has an outer tube, a rod inserted into and out of the outer tube, and a bump stopper rubber provided on a rod side and a bump stopper provided on an end of the outer tube.

  In such a shock absorber, at the time of the most contraction in which the rod enters the outer tube most, the bump stopper rubber abuts against the bump stopper and is compressed, so that the bump stopper rubber exerts a resilient force. Shock is reduced.

  The bump stopper includes a cylindrical portion having a perfectly circular cross section fitted to the outer periphery of the end portion of the outer tube, and an annular stopper portion provided at the top of the cylindrical portion and facing the bump cushion rubber and allowing the rod to pass therethrough. And fitted to the outer periphery of the end of the outer tube.

  More specifically, the bump stopper is provided with a plurality of protrusions arranged in the circumferential direction on the inner periphery of the cylindrical portion, and presses the protrusions on the outer periphery of the outer tube to tighten the outer tube and fix the outer tube to the outer tube. (For example, see Patent Document 1). In other words, the conventional bump stopper is fixed to the outer tube by press-fitting, thereby preventing the bump stopper from falling off from the outer tube.

JP 2009-222223 A

  As described above, the conventional bump stopper is fixed to the outer tube by the tightness of the outer tube. Therefore, if the diameter of the cylindrical portion is reduced, a large tightening force is obtained, and the fixing to the outer tube is ensured.

  However, when the above-mentioned tightening force is increased, when the bump stopper is pressed into the outer periphery of the end portion of the outer tube, a large stress acts on the bump stopper, and the possibility that the bump stopper is broken is increased.

  However, if the tension is reduced, the bump stopper may fall off from the outer tube. Therefore, it is difficult to reduce the tension with the conventional bump stopper.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a bump stopper and a shock absorber which can prevent cracking when the outer tube is attached to the outer periphery of the end portion and prevent the outer tube from falling off.

  In order to solve the above-mentioned object, a bump stopper according to the present invention is provided with a cylindrical portion that is elastically deformed by fitting to an outer periphery of an end portion of an outer tube of a shock absorber, And a claw that enters a groove provided on the outer periphery of the outer tube by deformation. In the bump stopper configured as described above, the bump stopper is fixed to the outer tube by using a claw in the groove, instead of using a tension force. Since a large amount of tension is not required to fix the bump stopper to the outer tube, the stress acting on the cylindrical portion when the bump stopper is mounted on the outer periphery of the end of the outer tube can be extremely reduced.

  Also, in the circumferential direction of the cylindrical portion, in the bump stopper where the rigidity of the portion of the cylindrical portion where the claw is provided and the surrounding portion is lower than the rigidity of the other portions, the portion provided with the claw is easily deformed. When the cylindrical portion is fitted to the outer periphery of the outer tube, the claws easily enter the groove and the effect of preventing the cylindrical portion from cracking increases.

  In order to make the rigidity of the portion where the claws are provided in the cylindrical portion and the peripheral portion thereof lower than the rigidity of the other portions in the circumferential direction of the cylindrical portion, the thickness of the portion where the claws are provided and the peripheral portion thereof is reduced. Is preferably made thinner than the thickness of the other portions, and the rigidity can be easily reduced without forming the cylindrical portion with a plurality of materials.

  In addition, the inner peripheral shape of the cylindrical portion is elliptical when viewed in the axial direction, the minor diameter of the inner peripheral portion of the cylindrical portion is shorter than the outer diameter of the outer tube, and the major diameter of the inner peripheral portion of the cylindrical portion is smaller than that of the outer tube. The bump stopper may be configured to be longer than the outer diameter and to be provided on the long axis of the inner circumference of the cylindrical portion. In the bump stopper configured as described above, the distance between the claws becomes long, and the tension force of the claws can be reduced when the cylindrical portion is fitted to the outer periphery of the outer tube, so that the burden on the cylindrical portion is also small. In addition, since the cylindrical portion has an elliptical shape, the shape does not change significantly when viewed in the circumferential direction, so that stress is less likely to be concentrated due to elastic deformation at the time of fitting to the outer tube. Therefore, the bump stopper configured as described above has a high crack prevention effect when fitted to the outer tube.

  In a shock absorber in which the groove provided on the outer periphery of the outer tube is an annular groove provided along the entire circumference of the outer tube, the bump stopper can be used without positioning the claw and the groove in the circumferential direction. Since it can be mounted on the outer periphery of the outer tube, the mounting work becomes easy.

  ADVANTAGE OF THE INVENTION According to the bump stopper of this invention, and the shock absorber provided with a bump stopper, prevention of the crack at the time of mounting | wearing the outer periphery of the end part of an outer tube of a bump stopper can prevent both of prevention of a bump stopper falling off from an outer tube.

It is a side view of the shock absorber provided with the bump stopper in one embodiment of the present invention. It is a top view of a bump stopper in one embodiment of the present invention. (A) is a top view of the 1st modification of a bump stopper in one embodiment of the present invention. (B) is a top view of the 2nd modification of a bump stopper in one embodiment of the present invention. (C) is a top view of the 3rd modification of a bump stopper in one embodiment of the present invention.

  Hereinafter, the present invention will be described based on the embodiment shown in the drawings. As shown in FIG. 1, the bump stopper 1 according to one embodiment is mounted on the outer peripheral end of the outer tube 10 of the shock absorber D, and is mounted on the tip of the rod 11 of the shock absorber D. Facing. When the bumper D contracts to a preset position, the bump stopper 1 comes into contact with the lower end of the bump cushion rubber 13 in FIG. 1 to compress the bump cushion rubber 13 and to attach the bumper rubber 13 to the bump cushion rubber 13. Exhibits elasticity that suppresses contraction. As described above, the bump stopper 1 cooperates with the bump cushion rubber 13 to reduce the shock when the shock absorber D contracts most.

  The shock absorber D includes a shock absorber main body 9 having a cylindrical outer tube 10 and a rod 11 inserted into and out of the outer tube 10 and the bump stopper 1. 11 exerts a damping force when it expands and contracts in the axial direction. A bump stopper 1 is mounted on the outer periphery of the upper end of the outer tube 10 in FIG. A groove 10a is provided on the outer periphery of the outer tube 10 near the upper end in FIG. 1, and the groove 10a is an annular groove extending in the circumferential direction over the entire outer periphery of the outer tube 10. A seal member 12 for sealing the outer periphery of the rod 11 and an annular rod guide (not shown) for guiding the axial movement of the rod 11 are accommodated and fixed to the inner periphery of the upper end of the outer tube 10 in FIG. .

  Although not shown in detail, the shock absorber D is connected to the cylinder accommodated in the outer tube 10 and the rod 11, and is movably inserted into the cylinder so as to extend through the cylinder into a side chamber and a pressure chamber. A partitioning piston is provided, and a reservoir is provided between the cylinder and the outer tube 10. The expansion side chamber and the compression side chamber are filled with liquid, and the reservoir is filled with liquid and gas. Further, the shock absorber D is provided with a passage communicating the extension side chamber and the compression side chamber and a passage communicating the compression side chamber with the reservoir, and a damping valve and a check valve for exerting a damping force in these passages are appropriately provided. Provided. When the shock absorber D is configured to extend, the damper D exerts a damping force that impedes expansion by imparting resistance to the flow of liquid from the expanding pressure side chamber to the contracting expansion side chamber by the damping valve. Conversely, when the shock absorber D contracts, the rod 11 penetrates into the cylinder, the liquid is pushed out from the cylinder, and the damping force that impedes the contraction by giving resistance to the flow of the liquid from the pressure side chamber to the reservoir by the damping valve. Demonstrate.

  In the above description, the shock absorber D is described as a double-cylinder type shock absorber. However, the shock absorber D is not limited to the double-cylinder type and exhibits a damping force when the rod 11 enters and exits the outer tube 10. Should be fine. Therefore, the shock absorber D may be a single-tube (mono-tube) shock absorber in which a piston is directly inserted into the outer tube 10 and the extension side chamber and the pressure side chamber are provided inside the outer tube 10. Further, the shock absorber D may be a single rod type shock absorber or a double rod type shock absorber. The liquid used in the shock absorber D may be a liquid such as a magnetic viscous fluid, an electrorheological fluid, water, or an aqueous solution in addition to the hydraulic oil. Instead of a damping valve, a device for applying a magnetic field or an electric field to a passage can be used.

  A cylindrical bump cushion rubber 13 is attached to the outer periphery of the distal end of the rod 11. As shown in FIG. 1, the bump cushion rubber 13 is formed in a cylindrical shape having bellows made of synthetic resin, rubber, or the like, and the lower end in FIG. 1 faces the bump stopper 1.

  In the present embodiment, the bump stopper 1 is made of a synthetic resin, and as shown in FIGS. 1 and 2, a cylindrical portion 2 fitted to the outer periphery of an end portion of the outer tube 10 of the shock absorber D, and a cylindrical portion. A claw 3 provided on the inner periphery of the cylinder 2 and entering the groove 10a; and an annular stopper 4 provided on the upper end of the cylindrical portion 2 in FIG. 1 to allow the rod 11 to pass therethrough and face the lower end of the bump cushion rubber 13. It is comprised including.

  As shown in FIG. 2, the cylindrical portion 2 has an elliptical shape when viewed from the axial direction, and an inner peripheral shape has an elliptical shape. The length of the minor axis, which is the diameter of the minor axis S on the inner periphery of the cylindrical portion 2, is shorter than the diameter of the outer periphery of the outer tube 10 indicated by the broken line in FIG. Is longer than the diameter of the outer periphery of the outer tube 10.

  The claws 3 are arranged on the long axis L in the inner periphery of the cylindrical portion 2 and are provided at two places on the inner periphery of the cylindrical portion 2. In the present embodiment, before the bump stopper 1 is fitted to the outer tube 10, the distance between the claws 3 is longer than the outer diameter of the outer tube 10.

  When the cylindrical portion 2 is viewed in the circumferential direction, the thickness of the portion A around the portion where the claws 3 and 3 are provided is smaller than the thickness of the other portions B. The portion A has a lower rigidity than the portion B, and is easily deformed by a small stress. In the case of this embodiment, the mutually facing portions B, B on the short axis S of the cylindrical portion 2 are difficult to deform, and the mutually facing portions A, A on the long axis L of the cylindrical portion 2 are easily deformed.

  Therefore, the length between the portions B, B in the cylindrical portion 2 is shorter than the outer diameter of the outer tube 10. Therefore, when the cylinder 2 is fitted to the outer periphery of the upper end of the outer tube 10 in order to mount the bump stopper 1 on the outer periphery of the outer tube 10, the cylindrical portion 2 has the portions B and B of the outer tube 10. It comes into contact with the outer periphery and exhibits elastic deformation such that the portions A, A bend so that the distance between the portions B, B is separated. That is, when fitted into the outer periphery of the outer tube 10, the cylindrical portion 2 is elastically deformed such that the short diameter is enlarged and the long diameter is reduced. The portion B is a portion in the vicinity of the portion where the interval is narrowest in the cylindrical portion 2 and directly abuts on the outer periphery of the outer tube 10, and the portion A fits the cylindrical portion 2 to the outer tube 10. Then, it is a portion approaching the outer tube 10. As described above, since the elliptical cylindrical portion 2 is elastically deformed as described above, the elliptical cylindrical portion 2 is fitted into the outer tube 10 in a shape close to a circle following the outer periphery of the outer tube 10.

  When the cylindrical portion 2 is elastically deformed as described above, the claws 3 and 3 come into contact with the outer periphery of the outer tube 10 and tighten the outer tube 10 with a slight tension. When the upper end of the outer tube 10 enters the bump stopper 1 until the stopper portion 4 of the bump stopper 1 comes into contact with the upper end of the outer tube 10, the claws 3, 3 face the groove 10a and enter the groove 10a. Break in. That is, when the stopper portion 4 of the bump stopper 1 contacts the upper end of the outer tube 10, the bump stopper 1 and the outer tube 10 are designed such that the claw 3 for the bump stopper 1 faces the groove 10a of the outer tube 10. I have.

  Then, since the cylindrical portion 2 is elastically deformed as described above, the claws 3, 3 do not come out of the groove 10a when they enter the groove 10a. It does not get out of the inside of 10a. Therefore, the bump stopper 1 does not fall off the outer tube 10.

  Further, as described above, in the bump stopper 1 of the present invention, the bump stopper 1 is prevented from falling off from the outer tube 10 by the contact portion of the cylindrical portion 2 with the outer tube 10 and the tightening force of the claws 3. Instead, the nails 3, 3 are prevented from falling off by entering the groove 10a of the outer tube 10. Therefore, when the bump stopper 1 is attached to the outer periphery of the end portion of the outer tube 10, the elastic force of the cylindrical portion 2 causes the contact portion of the cylindrical portion 2 with the outer tube 10 and the tension force between the claws 3 and 3 to be extremely small. I'm done. As described above, since the stress acting on the cylindrical portion 2 can be extremely small as compared with the conventional bump stopper, there is a possibility that the bump stopper 1 may be broken when the bump stopper 1 is mounted on the outer periphery of the end of the outer tube 10. Disappears.

  As described above, the bump stopper 1 of the present invention includes the cylindrical portion 2 which is elastically deformed by fitting to the outer periphery of the end portion of the outer tube 10 of the shock absorber D, and the elastically deformable cylindrical portion 2 provided on the inner periphery of the cylindrical portion 2. And a claw 3 that enters a groove 10a provided on the outer periphery of the outer tube 10. In the thus configured bump stopper 1, the bump stopper 1 can be fixed to the outer tube 10 by using the claw 3 inserted into the groove 10a instead of using a tension force. Since a large amount of tension is not required to fix the bump stopper 1 to the outer tube 10, the stress acting on the cylindrical portion 2 when attaching the bump stopper 1 to the outer periphery of the end of the outer tube 10 can be extremely reduced. Therefore, according to the bump stopper 1 and the shock absorber D provided with the bump stopper 1 of the present invention, it is possible to prevent the bump stopper 1 from being cracked when being mounted on the outer periphery of the end of the outer tube 10, and to prevent the bump stopper 1 from coming out of the outer tube 10. It can be compatible with prevention of falling off.

  In the bump stopper 1 of the present embodiment, the inner peripheral shape of the cylindrical portion 2 is elliptical when viewed in the axial direction, and the minor diameter of the inner peripheral portion of the cylindrical portion 2 is smaller than the outer diameter of the outer tube 10. It is short, and the longer diameter of the inner circumference of the tube portion 2 is longer than the outer diameter of the outer tube 10, and the claw 3 is provided on the longer axis L of the inner circumference of the tube portion 2. When the bump stopper 1 is configured in this manner, the distance between the claws 3 is increased, and the tightening force of the claws 3 when the cylindrical portion 2 is fitted to the outer periphery of the outer tube 10 can be reduced. The burden on the cylinder 2 is also small. In addition, since the cylindrical portion 2 has an elliptical shape, the shape does not change significantly when viewed in the circumferential direction, so that stress is less likely to be concentrated due to elastic deformation at the time of fitting to the outer tube 10. Therefore, in the bump stopper 1 and the shock absorber configured as described above, the effect of preventing cracking when fitting to the outer tube 10 is enhanced.

  In the bump stopper 1 of the present embodiment, the inner peripheral shape and the outer peripheral shape of the cylindrical portion 2 are elliptical. However, even if only the inner peripheral shape is elliptical, the claw 3 is formed by the elastic deformation of the cylindrical portion 2. The bump stopper 1 can be fixed to the outer tube 10 by entering the inside of the outer tube 10. Further, the shape of the cylindrical portion 2 is not limited to the elliptical shape, and the shape of the cylindrical portion 2 is not limited as long as the claw 3 can be inserted into the groove 10a by the elastic force generated by the elastic deformation and the state can be maintained. . Therefore, the shape of the cylindrical portion 2 as viewed from the axial direction may be circular, triangular, or polygonal. The number of the claws 3 may be one or more, but from the viewpoint of preventing the bump stopper 1 from dropping from the outer tube 10, it is more advantageous to provide a plurality of claws.

  When the shape of the cylindrical portion 2 viewed from the axial direction is triangular or polygonal, if the claw 3 is provided on the inner periphery of the apex, the stress acting on the portion of the cylindrical portion 2 where the claw 3 is provided is reduced, so that the claw 3 is broken. This is advantageous from the viewpoint of prevention. In the present embodiment, the shape of the cylindrical portion 2 as viewed from the axial direction is an elliptical shape, and the claws 3, 3 are provided on the long axis L, and the distance between the claws 3, 3 is smaller than the outer tube. 10 is longer than the outer diameter. For this reason, when the cylindrical portion 2 is fitted to the outer periphery of the outer tube 10, the tension force of the claws 3 can be reduced, so that the load on the cylindrical portion 2 is reduced and the effect of preventing cracking is enhanced. When this is applied to a case where the cylindrical portion 2 is formed into a triangle or a polygon, as shown in FIG. 3, the diameter of a virtual circle V indicated by a broken line passing through the inner peripheral end of the claws 3 is indicated by a dashed line. What is necessary is just to make it larger than the diameter of the outer tube 10. In this case, the effect of preventing the cylindrical portion 2 from cracking increases.

  Further, in the bump stopper 1 of the present embodiment, in the circumferential direction of the cylindrical portion 2, the rigidity of the portion A where the claws 3 and 3 are provided in the cylindrical portion 2 and the rigidity of the surrounding portions B and B are the rigidity of the other portions B and B. It is lower. When the bump stopper 1 is configured as described above, the portion A provided with the claws 3 and 3 is easily deformed, and the fitting amount of the portion A is large when the cylindrical portion 2 is fitted to the outer periphery of the outer tube 10. As a result, the effect of preventing the cylindrical portion 2 from cracking increases, as well as the effect that the portions 3 and 3 easily enter the groove 10a. However, the effect of the present invention is not lost even when the strength of the rigidity is not provided in the circumferential direction of the cylindrical portion 2.

  In order to make the rigidity of the portion where the claws 3 and 3 are provided in the cylindrical portion 2 and the peripheral portion A thereof lower than the rigidity of the other portions B and B in the circumferential direction of the cylindrical portion 2, the present embodiment If the thickness of the portion A is made smaller than the thickness of the portion B as in the case of the bump stopper 1, the rigidity can be easily reduced without forming the cylindrical portion 2 with a plurality of materials.

  In the shock absorber D in the present embodiment, the groove 10a provided on the outer periphery of the outer tube 10 is an annular groove provided over the entire circumference along the circumferential direction. In the shock absorber D configured as above, the bump stopper 1 can be mounted on the outer periphery of the outer tube 10 without positioning the claw 3 and the groove 10a in the circumferential direction, so that the mounting operation is facilitated.

  In this embodiment, since the bump stopper 1 is made of a synthetic resin, the bump stopper 1 may be manufactured using injection molding in which a synthetic resin is poured into a mold. In the case where such a manufacturing method is adopted, as shown in FIG. 1, if the tapered portion 3a is provided on the inner peripheral side of the upper end of the claw 3 in FIG. 1, the bump stopper 1 after molding is removed from the mold. Becomes easier. Further, a tapered portion is provided on the inner periphery of the lower end in FIG. 1 of the cylindrical portion 2 and a tapered portion 3b is provided on the inner periphery of the lower end of the claw 3 in FIG. 1 to facilitate the fitting operation of the bump stopper 1 to the outer tube 10. Is also good.

  As described above, the preferred embodiments of the present invention have been described in detail, but modifications, variations, and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Bump stopper, 2 ... Cylindrical part, 3 ... Claw, 9 ... Buffer body, 10 ... Outer tube, 10a ... Groove, 11 ... Rod, A, B ... Part in the cylindrical part, D ... buffer, L ... Long axis

Claims (5)

A tubular portion that is elastically deformed by fitting to the outer periphery of the end of the outer tube of the shock absorber;
A claw provided on an inner periphery of the cylindrical portion and entering a groove provided on an outer periphery of the outer tube by elastic deformation of the cylindrical portion. 2. The bump stopper according to claim 1, wherein, in a circumferential direction of the cylindrical portion, rigidity of a portion of the cylindrical portion where the claw is provided and a portion around the portion are lower than rigidities of other portions. 3. The bump stopper according to claim 2, wherein, in a circumferential direction of the cylindrical portion, a thickness of a portion of the cylindrical portion where the claw is provided and a portion around the portion are thinner than thicknesses of other portions. 4. . The inner peripheral shape of the cylindrical portion is an elliptical shape when viewed in the axial direction,
The minor diameter of the inner circumference of the cylindrical portion is shorter than the outer diameter of the outer tube,
The major diameter of the inner circumference of the cylindrical portion is longer than the outer diameter of the outer tube,
4. The bump stopper according to claim 1, wherein the claw is provided on a long axis of an inner circumference of the cylindrical portion. 5. An outer tube, and a shock absorber body having a rod that moves in and out of the outer tube, and that exhibits a damping force when the rod moves in and out of the outer tube;
A bump stopper according to any one of claims 1 to 4,
The groove provided in the outer tube is an annular groove provided in a circumferential direction.

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