JP6987008B2 - Buffer stopper - Google Patents

Description

The present invention relates to a buffer stopper that stops displacement of movable members, relative displacement between members, etc. while exerting a buffering action. The cushioning stopper of the present invention is used, for example, as a rack end stopper for a steering rack for vehicles. The buffer stopper of the present invention is also used in the field of industrial equipment as well as automobile equipment.

The cushioning stopper is, for example, elastic made of a rubber material between the rack housing 51 and the rack 61 which are displaced relative to each other in the axial direction as shown in FIG. 6 as a rack end stopper used at the end of a steering rack in a vehicle steering device. It has a structure that compresses and deforms the body 82.

Generally, the impact (input) buffering by the cushioning stopper 81 attempts to absorb the kinetic energy due to the weight and velocity of the movable member (rack 61) by the displacement and reaction force of the elastic body 82 in the cushioning 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 in the diagram consisting of the displacement amount of the elastic body 82 and the reaction force.

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

Japanese Unexamined Patent Publication No. 8-133102

However, there is room for improvement in the above-mentioned prior art in the following points.

That is, in the elastic body 82 in the cushioning stopper 81, a corresponding strain is required in order to obtain a high reaction force such as a non-linear region as a characteristic of a general elastic material. In this regard, it is necessary to increase the stopper size in order to satisfy the required functions with the above-mentioned conventional structure, but it is not easy to increase the size because the design space is limited due to the relationship with peripheral parts.

As a method for solving the above problem, it is conceivable that the elastic body 82 deformed by the input fills the clearance (diametrical 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, since the only way to increase the amount of energy that can be absorbed is to increase the rigidity of the elastic body 82, there is a limit to the correspondence by the elastic body 82 alone.

In view of the above points, it is an object of the present invention to provide a buffer stopper capable of increasing the amount of energy that can be absorbed.

In order to solve the above problems, the cushioning stopper of the present invention comprises a housing provided with an inner peripheral surface and an end surface portion connected to the inner peripheral surface, and a movable member arranged so as to be axially displaceable on the inner peripheral side of the housing. A cushioning stopper interposed between the metal fittings that can be displaced in the axial direction together with the movable member, and the metal fittings that are held by the metal fittings and arranged between the metal fittings and the end face portion, and the metal fittings are placed on the end face portion. An elastic body that is axially compressed and expands radially outward between the metal fitting and the end face portion when displaced in an approaching direction, and an elastic body that is vertically displaceable on the outer peripheral side of the elastic body, and the elastic body is displaced. A ring member that is pressed by the elastic body and displaced in a direction of entering the radial gap between the housing and the metal fitting when expanded outward in the radial direction, and an inner peripheral surface of the ring member and / or the metal fitting. It is characterized by being provided on the outer peripheral surface and provided with a tapered inclined surface that expands the diameter of the ring member when the ring member is displaced.

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

Further, as an embodiment, in the buffer stopper described above, the ring member is characterized by having a cut portion or a partial slit on the circumference so that the diameter can be easily expanded.

Further, as an embodiment, in the buffer stopper described above, the ring member is characterized by including a barb-shaped engaging portion that defines an initial movement position with respect to the metal fitting by engaging with the metal fitting.

In the present invention, the elastic body presses the ring member in the process of being compressed and expanding radially outward, and the pressed ring member is displaced in the direction of entering the radial gap between the housing and the metal fitting. Since the inner peripheral surface of the ring member and the outer peripheral surface of the metal fitting are 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 expands with the displacement. , Pressed against the inner peripheral surface of the housing. Therefore, since the ring member is pressed against the inner peripheral surface of the housing to generate sliding resistance, it is possible to increase the amount of energy that can be absorbed by the amount of this sliding resistance generated.

It is preferable that the ring member is made of a material having higher rigidity than the elastic body, which makes it difficult for the ring member to be compression-deformed and easily generate sliding resistance. It is preferable that the ring member is provided with a cut portion or a partial slit on the circumference, which makes it easy for the ring member to expand in diameter. Further, it is preferable that the ring member is provided with a barb-shaped engaging portion that engages with the metal fitting, which makes it possible to specify the initial movement position of the ring member with respect to the metal fitting.

Sectional drawing of the main part of the cushioning stopper which concerns on embodiment (A) is a perspective view of the buffer stopper, and (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 diagram showing the relationship between displacement and reaction force in the buffer stopper Cross-sectional view of the main part of the shock absorber according to another embodiment Cross-sectional view of the main part of the cushioning stopper according to the prior art Graph diagram 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 steering device of a vehicle, and as shown in FIG. 1, a rack as a housing and a movable member that are displaced relative to each other in the axial direction. It is interposed between the housing 51 and the rack 61 and exerts a stopper action while exerting a buffering action. 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 an axial other direction.

The rack housing 51 includes an inner peripheral surface 52, and also includes an annular end surface portion 53 having an axially perpendicular plane shape continuous from the other end portion of the inner peripheral surface 52 in the axial direction. 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 also includes an annular step portion 63 that is continuous from one end of the outer peripheral surface 62 in the axial direction. Therefore, 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 step portion 63 of the rack 61, and the cushioning stopper 11 forming an annular shape as a whole is mounted in the mounting space 71. Has been done.

The cushioning stopper 11 includes a metal fitting 21, an elastic body 31, and a ring member 41. The cushioning stopper 11 is composed of a metal fitting 21, an elastic body 31, and a ring member 41.

The metal fitting 21 is formed in an annular shape by a predetermined metal, and integrally includes a tubular portion 22 and a flange portion 23 provided from one end of the tubular portion 22 in the axial direction outward in the radial direction. It is formed in an L-shaped cross section. The metal fitting 21 is engaged with the step portion 63 of the rack 61, so that when the rack 61 is displaced to the other in the axial direction, the rack 61 is also displaced to the other in the axial direction, that is, it approaches the end face 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 therefore, in the radial direction between the outer peripheral surface of the metal fitting 21 and the inner peripheral surface 52 of the rack housing 51. A gap 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 tubular portion 22 and the other end surface in the axial direction of the flange portion 23). 32 and an elastic body leg 33 provided from the elastic body main body 32 toward the other in the axial direction are integrally provided. The elastic leg portion 33 is formed so as to protrude in the other axial direction from the end portion of the metal fitting 21 (the other end portion in the axial direction of the tubular portion 22), and the tip portion thereof is initially formed on the end face portion 53 of the rack housing 51. Is in contact with. The outer peripheral surface of the elastic body 31 is not in contact with the inner peripheral surface 52 of the rack housing 51, and thus the initial radial gap c _{2 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 by a material having a 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, to displace in the direction of entering the radial gap c1 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 circumferential surface 52 of the rack housing 51, thus initial radial clearance c ₃ between the inner peripheral surface 52 of the outer peripheral surface and the rack housing 51 of the ring member 41 Is formed.

Further, the ring member 41 is can be elastically deformed so as to expand its diameter when displaced in a direction to enter radially clearance c ₁ between the housing 51 and fitting 21, the ring during displacement 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 can be expanded and deformed.

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

Accordingly, when displaced in the direction of the ring member 41 enters into the radial gap c ₁ between the housing 51 and fitting 21, the ring member 41 is expanded deformation.

Further, in order to facilitate the expansion and deformation of the ring member 41, as shown in FIG. 2A, a cut portion 43 is provided at one position on the circumference of the ring member 41, and the ring member 41 is the cut portion 43. It is divided on the circumference. Instead of this, the cut portion 43 may have a plurality of slits 44 on the circumference as shown in FIG. 2 (B).

In the cushioning stopper 11 having the above configuration, when the rack 61 is displaced in the other direction in the axial direction from the state of FIG. 1, the metal fitting 21 is displaced together with the rack 61, the elastic body 31 is compressed, and the elastic body 31 expands outward in the radial direction, 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. Ring member 41 pressed is displaced in a direction to enter radially clearance c ₁ between the housing 51 and fitting 21, an enlarged diameter along the tapered inclined surfaces 42,24 in the course of displacement, of the housing 51 It is pressed against the peripheral surface 52. Therefore, since the ring member 41 is pressed against the inner peripheral surface 52 of the housing 51 and is displaced while generating sliding resistance, it is possible to increase the amount of energy that can be absorbed by the amount of the reaction force due to the sliding resistance. Will be done.

Therefore, the cushioning characteristics of the buffer stopper 11 are shown by solid lines in the graph of FIG. 4 (dotted lines show comparative examples (FIG. 6)), and the characteristic lines are 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 operating position in FIG. 3 to the initial motion in FIG. 1 due to the reaction force of the elastic body 31.

It is conceivable that the configuration of the buffer stopper 11 according to the above embodiment may be added or changed as follows.

In the cushioning 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, respectively, in order to increase the diameter of the ring member 41. If the diameter can be increased, the 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.

_{When the radial gap c 2} between the housing 51 and the elastic body 31 is large in the process of returning the ring member 41 from the operating position of FIG. 3 to the initial motion position of FIG. 1 after operating with the cushioning stopper 11 according to the above embodiment. There is a concern that the ring member 41 may be displaced too much in the other direction in the axial direction. Therefore, as a countermeasure against this, as shown in FIG. 5, it is preferable to integrally provide the ring member 41 with the displacement-shaped engaging portion 45, and according to this, the displacement-shaped engaging portion 45 is the metal fitting 21. Since the initial movement position of the ring member 41 with respect 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 excessively displaced in the other direction in the 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 arcuate cross section is provided on the outer peripheral surface of the elastic body 31 so as to be easily pressed, and the ring member 41 is arranged on the outer peripheral side of the recess 34. The cross-sectional shape is not particularly limited, and it is sufficient that the ring member 41 can be pressed and displaced in one axial direction. Further, a portion that engages with the ring member 41 at the time of expansion may be provided on the elastic body 31, and the ring member 41 may be returned (pulled back) from the operating position of FIG. 3 to the initial motion position of FIG. 1 by this engagement. Further, in the case where the ring member 41 is provided with the skein-shaped engaging portion 45 as described above, the ring member 41 is shown by bringing the shaving-shaped engaging portion 45 into contact with the rack 61 at the time of high load. It is also possible to return from the operating position of 3 to the initial moving position of FIG.

11 Cushioning stopper 21 Metal fittings 22 Cylindrical part 23 Flange part 24, 42 Inclined surface 31 Elastic body 32 Elastic body body part 33 Elastic body leg part 34 Recess 41 Ring member 43 Cut part 44 Slit 45 Engagement part 51 Rack housing (housing)
52 Inner peripheral surface 53 End surface 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 cushioning 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 so as to be axially displaceable on the inner peripheral side of the housing.
A metal fitting that can be displaced in the axial direction together with the movable member,
It is held by the metal fitting and is arranged between the metal fitting and the end face portion, and when the metal fitting is displaced in a direction approaching the end face portion, it is compressed axially between the metal fitting and the end face portion and expands radially outward. Elastic body and
It is arranged so as to be axially displaceable on the outer peripheral side of the elastic body, and is pressed by the elastic body when the elastic body expands radially outward to enter the radial gap between the housing and the metal fitting. Displaced ring member and
A cushioning stopper provided on an inner peripheral surface of the ring member and / or an outer peripheral surface of the metal fitting, and provided with a tapered inclined surface that expands the diameter of the ring member when the ring member is displaced. In the buffer stopper according to claim 1,
The ring member is a cushioning stopper characterized by being made of a material having a higher rigidity than the elastic body. In the buffer stopper according to claim 1 or 2.
The ring member is a cushioning stopper characterized by having a cut portion or a partial slit on the circumference so that the diameter can be easily expanded. In the buffer stopper according to claim 1, 2 or 3,
The ring member is a cushioning stopper comprising a barb-shaped engaging portion that defines an initial movement position with respect to the metal fitting by engaging with the metal fitting.

Images