JP2019173788A - Cushioning stopper - Google Patents

Abstract

To provide a cushioning stopper which can increase an absorbable energy amount.SOLUTION: A cushioning stopper 11 interposed between a housing 51 having an inner peripheral face 52 and an end face part 53, and a movable member 61 arranged at an inner peripheral side of the housing 51 so as to be displaceable in an axial direction comprises: metal fittings 21 displaceable in the axial direction together with the movable member 61; an elastic body 31 held by the metal fittings 21, arranged between the metal fittings 21 and the end face part 53, and compressed when the metal fittings are displaced in a direction where the metal fittings 21 approach the end face part 53 and expanded to the outside in a radial direction; a ring member 41 arranged at an outer peripheral side of the elastic body 31 so as to be displaceable in the axial direction, pressed by the elastic body 31 when the elastic body 31 is expanded, and displaced in a direction entering a clearance cin a radial direction between the housing 51 and the metal fittings 21; and tapered inclination faces 42, 24 which are provided at an inner peripheral face of the ring member 41 and an outer peripheral face of the metal fittings 21, and expand the diameter of the ring member 41 when the ring member 41 is displaced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a buffer stopper that stops displacement of a movable member and relative displacement between members while exhibiting a buffering action. The buffer stopper of the present invention is used as, for example, a rack end stopper of a vehicle steering rack. The buffer stopper of the present invention is also used in the field of industrial equipment in addition to automobile equipment.

  The buffer stopper is an elastic made of a rubber material between a rack housing 51 and a rack 61 that are relatively displaced in the axial direction as shown in FIG. 6 as a rack end stopper used at an end portion of a steering rack in a vehicle steering device, for example. The body 82 is configured to compress and deform.

  In general, shock (input) buffering by the buffer stopper 81 is intended to absorb kinetic energy due to the weight and speed of the movable member (rack 61) by the displacement and reaction force of the elastic body 82 in the buffer stopper 81. As shown in FIG. 7, the amount of energy that can be absorbed is determined by the size of the area S shown by the diagram composed of the displacement amount and reaction force of the elastic body 82.

  Therefore, in order to increase the amount of energy that can be absorbed, the displacement S of the elastic body 82 is increased or the reaction force (rigidity = spring constant) is increased to increase the area S shown in the diagram. It is common.

JP-A-8-133102

  However, the prior art has room for improvement in the following points.

  That is, the elastic body 82 in the buffer stopper 81 requires a corresponding distortion in order to obtain a high reaction force such as a non-linear region as a characteristic of a general elastic material. In order to satisfy the required function with the above-described conventional structure, it is necessary to increase the stopper size. However, since the design space is limited due to the relationship with the peripheral parts, the size expansion is not easy.

  As a method for solving the above problem, it is conceivable that the elastic body 82 deformed by input fills the clearance (radial gap) between the housing 51 and the stopper 81 to obtain a high reaction force.

  However, in this method, the amount of energy that can be absorbed is determined depending on the linear region characteristics of the elastic body 82 until the elastic body 82 fills the clearance between the housing 51 and the stopper 81. Therefore, in order to increase the amount of energy that can be absorbed, the rigidity of the elastic body 82 can only be increased.

  This invention makes it a subject to provide the buffer stopper which can increase the energy amount which can be absorbed in view of the above point.

  In order to solve the above-mentioned problems, a buffer stopper according to the present invention includes a housing provided with an inner peripheral surface and an end surface portion connected to the inner peripheral surface, and a movable member arranged to be axially displaceable on the inner peripheral side of the housing. A shock-absorbing stopper interposed between the metal member and the metal member that is axially displaceable together with the movable member; the metal member held between the metal member and the end surface part; and the metal member attached to the end surface part. An elastic body that is compressed in the axial direction between the metal fitting and the end face when expanded in the approaching direction and expands radially outward, and is disposed on the outer peripheral side of the elastic body so as to be axially displaceable. A ring member that is pressed by the elastic body when displaced outward in the radial direction and is displaced in a direction to enter a radial gap between the housing and the metal fitting, and an inner peripheral surface of the ring member and / or the metal fitting. Outside Provided on a surface, characterized by comprising the said tapered inclined surface which diameter ring member when the ring member is displaced.

  As an embodiment, in the buffer stopper described above, the ring member is made of a material having higher rigidity than the elastic body.

  As an embodiment, in the buffer stopper described above, the ring member is provided with a cut portion or a partial slit on the circumference so that the diameter can be easily increased.

  As an embodiment, in the buffer stopper described above, the ring member includes a hook-like engagement portion that defines an initial movement position with respect to the metal fitting by engaging with the metal fitting.

  In the present invention, in the process in which the elastic body is compressed and expanded radially outward, the elastic body presses the ring member, and the pressed ring member is displaced so as to enter the radial gap between the housing and the metal fitting. Since the tapered inner surface of the ring member or the outer peripheral surface of the metal fitting is provided with a tapered inclined surface that expands the diameter of the ring member when the ring member is displaced, the diameter of the ring member increases with displacement. And pressed against the inner peripheral surface of the housing. Therefore, sliding resistance is generated when the ring member is pressed against the inner peripheral surface of the housing. Therefore, the amount of energy that can be absorbed can be increased by the amount of generation of this sliding resistance.

  The ring member is preferably made of a material having higher rigidity than that of the elastic body, and according to this, the ring member is difficult to compress and deform and easily generates sliding resistance. The ring member is preferably provided with a cut portion or a partial slit on the circumference, and this facilitates the diameter expansion of the ring member. In addition, the ring member preferably includes a hook-like engaging portion that engages with the metal fitting, and according to this, it is possible to define the initial movement position of the ring member with respect to the metal fitting.

Sectional drawing of the principal part of the buffer stopper which concerns on embodiment (A) is a perspective view of the buffer stopper, (B) is a perspective view showing another example of the buffer stopper. Cross-sectional view of the main part showing the operating state of the buffer stopper Graph showing the relationship between displacement and reaction force in the buffer stopper Sectional drawing of the principal part of the buffer stopper which concerns on other embodiment Cross-sectional view of the main part of the buffer stopper according to the prior art Graph showing the relationship between displacement and reaction force in the buffer stopper

  The buffer stopper 11 according to the embodiment is used as a rack end stopper of a steering rack in a vehicle steering apparatus. As shown in FIG. 1, a housing that is relatively displaced in the axial direction and a rack as a movable member. It is interposed between the housing 51 and the rack 61 and exerts a stopper function while exhibiting a buffering function. Hereinafter, the upper part in FIG. 1 is referred to as one axial direction, and the lower part in FIG. 1 is also referred to as the other axial direction.

  The rack housing 51 includes an inner peripheral surface 52, and also includes an annular end surface portion 53 that is perpendicular to the axis and is continuous from the other axial end portion of the inner peripheral surface 52. The rack 61 includes an outer peripheral surface 62 that faces the inner peripheral surface 52 of the rack housing 51 in the radial direction, and an annular stepped portion 63 that is continuous from one end of the outer peripheral surface 62 in the axial direction. Accordingly, an annular mounting space 71 is provided by the inner peripheral surface 52 and the end surface portion 53 of the rack housing 51 and the outer peripheral surface 62 and the stepped portion 63 of the rack 61, and the buffer stopper 11 having an annular shape as a whole is mounted in the mounting space 71. Has been.

  The buffer stopper 11 includes a metal member 21, an elastic body 31 and a ring member 41. The buffer stopper 11 includes a metal member 21, an elastic body 31 and a ring member 41.

The metal fitting 21 is formed in an annular shape from a predetermined metal, and integrally includes a cylindrical portion 22 and a flange portion 23 provided radially outward from one axial end of the cylindrical portion 22. The cross section is formed in an L shape. The metal fitting 21 is engaged with the stepped portion 63 of the rack 61, so that when the rack 61 is displaced in the other axial direction, the rack 61 is also displaced in the other axial direction, that is, approaches the end surface portion 53 of the rack housing 51. Displace in the direction. A gap (not shown) may be formed between the inner peripheral surface of the metal fitting 21 and the outer peripheral surface 62 of the rack 61, that is, the metal fitting 21 may be loosely fitted to the rack 61. The outer peripheral surface of the metal fitting 21 (the outer peripheral surface of the flange portion 23) is not in contact with the inner peripheral surface 52 of the rack housing 51, and thus the radial direction is between the outer peripheral surface of the metal fitting 21 and the inner peripheral surface 52 of the rack housing 51. clearance c ₁ is formed.

The elastic body 31 is formed in an annular shape by a predetermined rubber, and is bonded (vulcanized and bonded) to the inner surface of the metal fitting 21 (the outer peripheral surface of the cylindrical portion 22 and the other end surface in the axial direction of the flange portion 23). 32 and an elastic body leg portion 33 provided from the elastic body main body portion 32 toward the other side in the axial direction are integrally provided. The elastic body leg portion 33 is formed so as to protrude in the other axial direction than the end portion of the metal fitting 21 (the other axial end portion of the cylindrical portion 22), and the end portion of the elastic body leg portion 33 is initially attached to the end surface portion 53 of the rack housing 51. Touching. The outer peripheral surface of the elastic body 31 is not in contact with the inner peripheral surface 52 of the rack housing 51, so that the initial radial gap c ₂ is between the outer peripheral surface of the elastic body 31 and the inner peripheral surface 52 of the rack housing 51. Is formed.

The ring member 41 is formed in an annular shape from a material having higher rigidity than the rubber of the elastic body 31, for example, a urethane material. The ring member 41 is disposed in the diametrical gap c ₂ between the rack housing 51 and the elastic body 31 a outer peripheral side of the elastic body 31 (elastic body 32), the axis when a pressing load is applied from the other axial It is possible to displace in one direction, that is, in a direction to enter the radial gap c ₁ between the rack housing 51 and the metal fitting 21. The outer peripheral surface of the ring member 41 is not in contact with the inner peripheral surface 52 of the rack housing 51, and thus the initial radial gap c ₃ is between the outer peripheral surface of the ring member 41 and the inner peripheral surface 52 of the rack housing 51. Is formed.

Further, the ring member 41 can be elastically deformed so as to increase its radial dimension when displaced in a direction to enter the radial gap c ₁ between the housing 51 and the metal fitting 21. Tapered inclined surfaces 42 and 24 are provided on the inner peripheral surface of the ring member 41 and the outer peripheral surface of the metal fitting 21 so that the member 41 is expanded in diameter.

  That is, an annular inclined surface 42 is provided on the inner peripheral surface of the ring member 41 so that the inner diameter dimension gradually decreases from one side to the other in the axial direction, and the outer peripheral surface of the metal fitting 21 extends from one side to the other in the axial direction. An annular inclined surface 24 having an outer diameter dimension gradually decreasing is provided. The inclined surface 42 provided on the inner peripheral surface of the ring member 41 is formed such that the maximum inner diameter is smaller than the maximum outer diameter of the inclined surface 42 provided on the outer peripheral surface of the metal fitting 21 and larger than the minimum outer diameter. The minimum inner diameter is formed smaller than the minimum outer diameter of the inclined surface 24 provided on the outer peripheral surface of the metal fitting 21. The inclined angles of both the inclined surfaces 42 and 24 are formed to be the same or substantially the same.

Therefore, when the ring member 41 is displaced in a direction to enter the radial gap c ₁ between the housing 51 and the metal fitting 21, the ring member 41 undergoes a diameter expansion deformation.

  Further, in order to facilitate the diameter expansion deformation of the ring member 41, a cut portion 43 is provided at one place on the circumference of the ring member 41 as shown in FIG. It is divided on the circumference. Instead of this, the cut part 43 may be a plurality of slits 44 on the circumference as shown in FIG.

In the buffer stopper 11 configured as described above, when the rack 61 is displaced in the other axial direction from the state of FIG. 1, the metal fitting 21 is displaced together with the rack 61, and the elastic body 31 is compressed and expanded radially outward as shown in FIG. and, although will be filled in diametrical gap c ₂ between the rack housing 51 and the elastic body 31, elastic body 31 in the expanded filling to process presses the ring member 41. The pressed ring member 41 is displaced in a direction to enter the radial gap c ₁ between the housing 51 and the metal fitting 21, and in the course of the displacement, the diameter is increased along the tapered inclined surfaces 42 and 24. It is pressed against the peripheral surface 52. Therefore, the ring member 41 is pressed against the inner peripheral surface 52 of the housing 51 and is displaced while generating sliding resistance. Therefore, the amount of energy that can be absorbed can be increased as the reaction force due to sliding resistance increases. Is done.

  Therefore, the buffering characteristic of the buffer stopper 11 is as shown by a solid line in the graph of FIG. 4 (the dotted line indicates a comparative example (FIG. 6)), particularly in the wire diameter region (between a and b). Since the rate of increase increases, the amount of energy that can be absorbed can be increased.

Also, in the operating state shown in FIG. 3, the ring member 41 because that would block the radial clearance c ₁ between the housing 51 and fitting 21, the elastic member 31 to prevent the breakage sandwiched in the gap c ₁ be able to.

  After the operation, the ring member 41 returns from the operation position in FIG. 3 to the initial movement in FIG. 1 by the reaction force of the elastic body 31.

  It is conceivable that the buffer stopper 11 according to the above embodiment is added / changed in its configuration as follows.

  In the buffer stopper 11 according to the above embodiment, tapered inclined surfaces 42 and 24 are provided on the inner peripheral surface of the ring member 41 and the outer peripheral surface of the metal fitting 21 in order to expand the diameter of the ring member 41. If the diameter can be increased, a tapered inclined surface may be provided on only one of the inner peripheral surface of the ring member 41 and the outer peripheral surface of the metal fitting 21.

After working with a buffer stopper 11 according to the above embodiment, when the ring member 41 is in the process of returning to the initial position of FIG. 1 from the operative position of FIG. 3, a large radial gap c ₂ between the housing 51 and the elastic body 31 There is a concern that the ring member 41 may be displaced too much in the other axial direction. Therefore, as a countermeasure, as shown in FIG. 5, it is preferable that the ring member 41 is integrally provided with a hook-like engagement portion 45, and according to this, the hook-like engagement portion 45 is provided with the metal fitting 21. Since the initial movement position of the ring member 41 relative to the metal fitting 21 is defined by engaging with the ring member 41, it is possible to prevent the ring member 41 from being displaced too much in the other axial direction.

Further, the cushioning stopper 11 according to the above embodiment, the elastic body 31 in the course of the elastic member 31 fills the radial gap c ₂ expands radially outward is compressed toward the ring member 41 in the axial direction while An annular recess 34 having an arc shape in cross section is provided on the outer peripheral surface of the elastic body 31 so that it can be easily pressed, and a ring member 41 is disposed on the outer peripheral side of the recess 34. The cross-sectional shape is not particularly limited as long as the ring member 41 can be pressed and displaced in one axial direction. Further, a portion that engages with the ring member 41 during expansion may be provided in the elastic body 31, and the ring member 41 may be returned (pulled back) from the operating position in FIG. 3 to the initial movement position in FIG. Further, when the ring member 41 is provided with the hook-like engagement portion 45 as described above, the ring member 41 is illustrated by bringing the hook-like engagement portion 45 into contact with the rack 61 when the load is high. 3 may be returned to the initial movement position of FIG.

DESCRIPTION OF SYMBOLS 11 Buffer stopper 21 Metal fitting 22 Cylindrical part 23 Flange part 24,42 Inclined surface 31 Elastic body 32 Elastic body main part 33 Elastic body leg part 34 Indentation 41 Ring member 43 Cut part 44 Slit 45 Engagement part 51 Rack housing (housing)
52 Inner peripheral surface 53 End surface portion 61 Rack (movable member)
62 outer peripheral surface 63 stepped portion 71 mounting space c ₁ , c ₂ , c ₃ radial gap

Claims (4)

A buffer stopper interposed between a housing provided with an inner peripheral surface and an end surface portion connected to the inner peripheral surface, and a movable member arranged to be axially displaceable on the inner peripheral side of the housing,
A metal fitting that is axially displaceable together with the movable member;
It is held by the metal fitting and is arranged between the metal fitting and the end surface portion, and is compressed in the axial direction between the metal fitting and the end surface portion and expands radially outward when the metal fitting is displaced in a direction approaching the end surface portion. An elastic body,
It is arranged on the outer peripheral side of the elastic body so that it can be displaced in the axial direction, and when the elastic body expands radially outward, it is pressed by the elastic body and enters the radial gap between the housing and the metal fitting. A ring member to be displaced;
A shock-absorbing stopper, comprising: a tapered inclined surface provided on an inner peripheral surface of the ring member and / or an outer peripheral surface of the metal fitting and expanding the diameter of the ring member when the ring member is displaced. The buffer stopper according to claim 1,
The buffer member, wherein the ring member is made of a material having higher rigidity than the elastic body. The buffer stopper according to claim 1 or 2,
The said ring member is provided with a cut part or a partial slit on the circumference so that it may be easy to expand diameter, The buffer stopper characterized by the above-mentioned. In the buffer stopper according to claim 1, 2, or 3,
The said ring member is provided with the hook-shaped engaging part which prescribes | regulates the initial movement position with respect to the said metal fitting by engaging with the said metal fitting, The buffer stopper characterized by the above-mentioned.

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