JP2018100758A - Elastic bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastic bush capable of increasing a radial length of an outer end surface without enlargement of an elastic material or reduction of a volume, and capable of suppressing a crack from occurring early on an outer end surface of the elastic material even in a case of receiving not only a radial load but also a torsional or gouged load, thereby improvement of durability can be achieved.SOLUTION: An elastic bush includes an inside member 1 comprising a shaft having a shaft center P, and an outer cylinder 2 peripherally provided at a radial outside of the inside member 1, where an elastic material 3 is interposed between the inside member 1 and the outer cylinder 2. An outer end surface 5 in a shaft center P direction of the elastic material 3 is formed into an uneven shape in the shaft center P direction, and provided is surface length increase means H of increasing a surface length in a radial direction of the outer end surface 5. The surface length increase means H comprises a corrugated outer end surface 5 formed by alternately connecting concave surfaces 6 and convex surfaces 7 to one another.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an elastic bushing suitable for a traveling vehicle such as a traction device for a railway carriage, and more specifically, a cylinder having an axis or an inner member composed of a shaft, and an outer cylinder provided around the outer diameter of the inner member. And an elastic bush in which an elastic material is interposed between the inner member and the outer cylinder.

  As this type of elastic bushing, as disclosed in a rubber bush (such as FIG. 1) used for a suspension arm of an automobile disclosed in Patent Document 1, and disclosed in Patent Document 2 (especially, see FIGS. 5 to 7). An elastic bush (buffer rubber G) used for a traction link (10) of a railway vehicle traction device is known.

  These elastic bushes are basically arranged so that the inner member and the outer cylinder exhibit a buffering action when receiving a radial force (load) on the shaft center. However, in an actual machine, a load is often applied in a direction in which the inner member and the outer cylinder are relatively twisted (twisted).

As shown in FIG. 6, the conventional elastic bush A includes a shaft-shaped inner member 1 having an axis P and an outer tube 2, and an annular elastic member 3 between the inner member 1 and the outer tube 2. It is configured with interposition. The outer end surfaces 5 and 5, which are end surfaces in the axis P direction of the elastic material 3, are formed as concavely curved surfaces in a state where the width in the axis P direction of the radial direction intermediate portion of the elastic material 3 is the smallest.
In the conventional elastic bush A, stress tends to concentrate on the outer end surface 5 of the elastic member 3, and there is a tendency that cracks are likely to occur therefrom.

As a means for improving the durability as an elastic bush by suppressing the tendency of the outer end surface (surface) of the elastic material to easily crack in an elastic bushing that receives twisting and twisting load in addition to axial load 3 and Patent Document 4 are shown.
The elastic bush disclosed in Patent Document 3 is an elastic material (main rubber elastic body 16) interposed between an inner member (inner tube bracket 12) and an outer tube (outer tube bracket 14). The outer end surface, which is the surface in the axial center (L) direction, has a recessed shape that is largely recessed in the axial center (L) direction. Also in patent document 4, the device similar to the thing of patent document 3 is made | formed by the elastic material (40).

  In Patent Documents 3 and 4, in conditions where the thickness of the elastic material is constrained, the outer end surface is greatly increased in depth to avoid stress concentration and early cracks occur on the outer end surface. It is a means to make it hard to generate. However, with the means for making a large recess, the volume reduction of the elastic material cannot be ignored unless the size of the elastic bushing itself is changed, and when the elastic material volume is secured, the elastic material, that is, the elasticity Since the size of the bush increases in the axial direction or the like, it is difficult to realize in any case. Therefore, in order to increase the radial length of the outer end surface without increasing the size of the elastic bush and without reducing the volume of the elastic material, further improvement is required.

Japanese Patent Laid-Open No. 11-051099 JP 2009-051420 A JP, 2015-010627, A JP 2006-017523 A

  The purpose of the present invention is to further increase the radial length of the outer end surface without incurring an increase in the size and volume of the elastic material through further structural improvements, while receiving not only radial load but also twisting and twisting load. However, the present invention is to provide an elastic bushing that is prevented from being cracked early on the outer end surface of the elastic material and can improve durability.

The invention according to claim 1 includes an inner member 1 made of a cylinder or shaft having an axis P, and an outer cylinder 2 provided on the outer diameter side of the inner member 1, and the inner member 1 and the outer cylinder. In an elastic bush in which an elastic material 3 is interposed between
Surface length increasing means H for increasing the surface length of the outer end surface 5 in the radial direction by making the outer end surface 5 in the axis P direction of the elastic material 3 uneven in the axis P direction is provided. It is characterized by.

The invention according to claim 2 is the elastic bush according to claim 1,
The surface length increasing means H is formed by forming the outer end surface 5 into a wave shape in which the concave curved surface 6 and the convex curved surface 7 are alternately connected in the radial direction.

The invention according to claim 3 is the elastic bush according to claim 1,
The surface length increasing means H is formed by forming a cut 8 in the elastic material 3 that has a bottom portion 9 that is round and expands and extends from the outer end surface 5 in the direction of the axis P.

The invention according to claim 4 is the elastic bush according to any one of claims 1 to 3,
The outer end surface 5 has a length Lt in the axial center P direction of the radially intermediate portion of the elastic member 3 in the axial center P direction of the joint portion between the inner member 1 and the outer cylinder 2 of the elastic member 3. It is formed in the concave curved surface shorter than length L1, L2.

The invention according to claim 5 is the elastic bush according to any one of claims 1 to 4,
The axis P is for a railway vehicle set to an axis in a direction X intersecting the vehicle traveling direction Z.

According to the first aspect of the present invention, the elastic bushing is excessively sized without increasing the size of the elastic bushing in the axial direction or the direction of the center line by the surface length increasing means for making the outer end surface uneven in the axial direction. The length of the outer end surface in the radial direction is increased without being reduced so that stress concentration is less likely to occur.
As a result, through further structural improvements, without increasing the size and volume of the elastic material, the radial length of the outer end surface is increased, and while receiving not only radial load but also twisting and twisting load, it is elastic It is possible to provide an elastic bushing in which cracks are prevented from occurring early on the outer end surface of the material and durability can be improved.

  Invention of Claim 2 is a surface length increasing means which makes a corrugated outer end surface which connected the concave curved surface and the convex curved surface alternately to radial direction, and invention of Claim 3 has the bottom part expanded circularly. It is a surface length increasing means for forming a cut extending in the axial direction from the outer end surface in the elastic material.

  The invention according to claim 4 is an elastic bushing in which the outer end surface of the elastic material is formed in a concave curved surface, and the invention according to claim 5 is a method in which the axis of the inner member intersects the vehicle traveling direction. It is an elastic bush for a railway vehicle set at the shaft center.

The elastic bush is shown, (a) is a partially cutaway side view, (b) is a front view. Sectional drawing which shows the principal part of the elastic material in Fig.1 (a) Side view of a partially cutout showing a modification of the elastic bush (Embodiment 2) The side view of the notch which shows the elastic bush of Embodiment 3 Sectional drawing which shows the principal part of the elastic material in FIG. Side view of a partially cutaway showing a conventional elastic bush

  Hereinafter, an embodiment of an elastic bush according to the present invention will be described for a railway vehicle with reference to the drawings. In each figure, the arrow X direction that is the direction of the axis P is the left and right, the arrow Y direction that is the direction of the center line W is up and down, and the arrow Z direction is front and back. The arrow X is sometimes referred to as “direction X”.

Embodiment 1
As shown in FIGS. 1 and 2, the elastic bush A includes a support shaft (an example of an inner member) 1 that is a shaft-shaped member having an axis P, and an outer cylinder that is provided on the outer diameter side of the support shaft 1. 2 and a cylindrical rubber (an example of an elastic material) 3 that fills an annular gap between the spindle 1 and the outer cylinder 2 is provided. As an example of use of the elastic bush A in an actual machine, the axis P is for a railway vehicle in which the axis P is set to the axis X in the direction X intersecting the vehicle traveling direction Z. As disclosed, there are configurations used before and after the traction link.

  As shown in FIG. 1 and FIG. 2, the support shaft 1 is made of metal and includes a mounting portion 1A, 1A at both ends in the longitudinal direction and a support portion 1B at the middle (center) in the longitudinal direction. A cylindrical rubber 3 is fixed to the outer peripheral surface 1b of 1B. The support portion 1B is a cylindrical portion, and each attachment portion 1A, 1A has a slightly smaller diameter (same diameter or larger diameter is possible) than the support portion 1B, and has a flat attachment surface 1a in the front and rear. Thus, the shape in the left-right direction is an oval shape. Each attachment portion 1A, 1A is provided with an attachment hole 4 for passing a bolt layer.

  As shown in FIG. 1 and FIG. 2, the outer cylinder 2 made of a metal ring such as a steel plate is disposed concentrically outside the diameter of the support portion 1 </ b> B. The support shaft 1 and the outer cylinder 2 are formed symmetrically with respect to the center line W. The lateral width of the outer cylinder 2 is set to a length that is slightly narrower than the lateral width of the support portion 1B. The cylindrical rubber 3 is filled in the annular space between the support shaft 1 and the outer cylinder 2 while being fixed to the outer peripheral surface 1b of the support portion 1B and the inner peripheral surface 2a of the outer cylinder 2 by vulcanization adhesion. Has been placed.

  When viewed as a whole, each outer end surface 5 basically has a length Lt in the axial center P direction of the radial intermediate portion of the elastic material 3 that is joined to the support shaft 1 of the elastic material 3 and the outer cylinder 2 respectively. It is formed in a concave curved surface shorter than the lengths L1 and L2 in the axis P direction of the portion (see also FIG. 6). For example, the radial direction intermediate part length Lt is 50 to 70 mm (preferably 63 mm), the inner diameter side length L1 is 90 to 110 mm (preferably 102 mm), and the outer diameter side length L2 is 70 to 90 mm (preferably 80 mm). Although each is set, it is not limited to these values. Surface length increasing means H is provided on the outer end surface 5 which is the basic concave curved surface.

  As shown in FIG. 1 and FIG. 2, the surface length increasing means H is configured such that the outer end surface 5, which is the end surface of the elastic material 3 in the axial center P direction, is uneven in the axial center P direction. It increases the surface length. That is, it is formed by forming a wave shape in which the concave curved surface (concave arc surface) 6 and the convex curved surface (convex arc surface) 7 are alternately connected in the radial direction. The plurality of concave and convex curved surfaces 6 and 7 are continuously formed in the circumferential direction of the outer end surface 5 and have an annular shape when viewed in the direction of the axis P. The length in the radial direction of the outer end surface 5 can be increased without difficulty by the surface length increasing means H based on the uneven curved surface.

  That is, the radial length of the outer end surface 5 is not increased by the surface length increasing means H without increasing the size of the elastic bush A in the direction of the axis P or the direction of the center line W and without excessively reducing the volume of the elastic material 3. Can be increased. As a result, in the elastic bushing that receives twist and torsional displacement in addition to the axial load, the stress concentration on the outer end surface 5 is reduced, and the durability is improved.

[Embodiment 2]
FIG. 3 shows an elastic bush A according to the second embodiment. This elastic bush A is the same as that shown in FIGS. 1 and 2 except that the support shaft 1 of the elastic bush A of the first embodiment shown in FIGS. 1 and 2 is replaced with a metal cylinder member 1 having an inner peripheral surface 1c. This is the same as the elastic bush A. Accordingly, the corresponding portions are denoted by the same reference numerals and description thereof is omitted.

[Embodiment 3]
4 and 5 show an elastic bush A according to the third embodiment. The elastic bush A of the third embodiment is the same as the elastic bush A of the first embodiment except that the surface length increasing means H is different, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 5, the surface length increasing means H of the elastic bush A according to the third embodiment has a cutout 8 formed in the elastic member 3 having a bottom portion 9 that is expanded in a round shape and extending from the outer end surface 5 in the axis P direction. It is comprised by doing. The bottom 9 is formed in an inner spherical shape (inner surface of a sphere) as an example.

  The depth (length in the axis P direction) d of the cut 8 is set to a length (eg, 4.6 mm) that is not too deep and is not too shallow. Although the five incisions 8 which are circumferential grooves continuously formed around the axis P are concentric and formed in the radial direction at equal intervals or unequal intervals, the number of the incisions 8 may be more or less. Due to the plurality of cuts 8, the radial length of the outer end surface 5 is dramatically increased, and the rounded bottom portion 9 suppresses the cracks 8 from first causing cracks.

[Another Example]
The surface length increasing means H is one in which narrower or large uneven curved surfaces are alternately connected (modified example of the first embodiment), or the shape and depth of the cut 8 and the cut direction are changed (third embodiment). Or other modifications.

1 Inner member (support shaft)
2 Outer cylinder 3 Elastic material (cylindrical rubber)
5 outer end surface 6 concave curved surface 7 convex curved surface 8 notch 9 bottom H surface length increasing means L1 axial length of the joint portion with the inner member of the elastic material L2 axial center P direction of the joint portion with the outer cylinder of the elastic material Length Lt Length in the axial center direction of the radial intermediate portion of the elastic material P Axis center X Direction intersecting the vehicle traveling direction Z Vehicle traveling direction

Claims (5)

An elastic member comprising an inner member made of a cylinder having a shaft or a shaft and an outer cylinder provided on the outer diameter side of the inner member, and an elastic material interposed between the inner member and the outer cylinder. A bush,
An elastic bush provided with surface length increasing means for increasing the surface length in the radial direction of the outer end surface by making the outer end surface in the axial direction of the elastic material uneven in the axial direction.   2. The elastic bush according to claim 1, wherein the surface length increasing means is formed by forming the outer end surface into a wave shape in which concave curved surfaces and convex curved surfaces are alternately connected in a radial direction.   The elastic bush according to claim 1, wherein the surface length increasing means is formed by forming a cut in the elastic member extending in the axial direction from the outer end surface having a bottom portion that is rounded and expanded.   The outer end surface is a concave curved surface in which the length in the axial center direction of the radially intermediate portion of the elastic material is shorter than the length in the axial direction of the joint portion of the elastic material with each of the inner member and the outer member. The elastic bush as described in any one of Claims 1-3 currently formed in.   The elastic bush according to any one of claims 1 to 4, wherein the axial center is for a railway vehicle set to an axial center in a direction intersecting the vehicle traveling direction.

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