JP3731488B2 - Vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration isolating device such as a suspension bush of a vehicle or an engine mount, and more particularly to a vibration isolating device in which an outer cylinder member press-fitted into a shaft hole of a cylindrical mating attachment member is made of resin.
[0002]
[Prior art]
Conventionally, as shown in FIG. 5, for example, this type of vibration isolator has a cylindrical inner cylindrical member 1 and a cylindrical shape having a straight inner and outer peripheral surface disposed radially outward and between both axial ends. An outer cylindrical member 2 provided with an annular outer flange portion 4 projecting radially outward at one axial end thereof and an inner cylindrical member 1 and the outer cylindrical member 2, A substantially cylindrical rubber elastic body portion 6 that elastically connects the inner and outer cylindrical members 1 and 2 is provided. The other end side of the outer cylinder member 2 is an insertion end portion 5 whose outer peripheral surface is inclined in a tapered manner toward the tip in order to press fit into a cylindrical mating attachment member 31 as shown in FIG.
[0003]
About the said outer cylinder member 2, since it is excellent in the weight reduction of a vibration isolator, the reduction | decrease of metal mold | die cost, and the rust prevention performance with respect to the conventional metal things, such as iron, the resin-made member is employ | adopted. It is becoming. The resin outer cylinder member 2 is press-fitted into the shaft hole 32 of the mounting member 31 which is a cylindrical fitting provided with a chamfered portion 33 from the axial end portion 5 side, and the flange portion 4 is fitted to one end of the mounting member 31. It is pushed in and fixed until it comes into contact.
[0004]
Here, since the resin-made outer cylinder member 2 is softer than a metal-made outer member, in order to form a tightly fixed state with the mounting member by press-fitting into the metal-made mounting member 31, and to secure a pulling force. In addition, the press-fitting allowance, which is the amount of compression that is compressed by being pressed by the mounting member 31, is set to a large value of about 2 mm on both sides in the radial direction. Therefore, the insertion end portion 5 of the outer cylinder member 2 is so-called galling that is caught when press-fitted into the attachment member 31 unless it is a tapered surface that is inclined and tapered toward the tip within a predetermined angle range. Will occur and it will not be possible to press fit. Therefore, it is desirable that the angle of the tapered surface is, for example, about 10 ° to 30 °.
[0005]
On the other hand, for the press-fitting guide in consideration of press-fitting properties, the tip of the insertion end portion 5 of the outer cylinder member 2 is provided by providing a taper surface so that the taper guide is elongated within the range of such an inclination angle. The side becomes thin. Therefore, when the outer cylinder member 2 is pressed into the mounting member 31, when the outer cylinder member 2 is pressed with a mold during vulcanization molding, or when the outer cylinder member 2 is dropped, the outer cylinder member 2 does not have strength. Result. On the other hand, in order to give the strength on the tip side, the thickness of the outer cylinder member 2 may be increased as a whole. However, if the wall thickness of the outer cylinder member 2 is made too thick, the spring characteristics of the vibration isolator are impaired, and a large amount of resin material is required by increasing the wall thickness. There is a problem that the weight increases and the member cost increases. Therefore, the thickness of the outer cylinder member 2 is limited to about 2 to 3 mm. However, when the thickness of the outer cylinder fitting 2 is about 2 to 3 mm, the tip side becomes extremely thin as described above, and when the outer cylinder member is pressed into the mounting member 31 or when the outer cylinder member is pressed during vulcanization molding. The result is not as strong as possible.
[0006]
In order to avoid such an inconvenience, as shown in FIG. 6, the straight cylindrical portion 3 of the outer cylindrical member 2 is an insertion end portion 5 a that is slightly bent and inclined in the axial direction as a whole on the distal end side. Thereby, the thinness of the insertion end 5a can be eliminated. However, in the case of this vibration isolator, when the outer tube member 2 is press-fitted into the mounting member 31, the tube portion 2 is squeezed so that the bent insertion end portion 5a is conversely radially outward at the boundary with the straight portion. It will be in the state where force is applied to the direction and it bends. Therefore, there is a problem that the insertion end portion 5a is subjected to stress at the boundary with the straight portion, and defects such as cracks are likely to occur.
[0007]
The present invention is intended to solve the above-described problems, and press-fit a resin outer cylinder member whose insertion end side is inclined in a tapered state toward the tip into a shaft hole of a metal cylindrical mounting member. An object of the present invention is to provide a vibration isolator that does not cause defects such as cracks at the insertion end when fixed.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the structural features of the invention according to claim 1 include an inner cylindrical member, and a cylindrical portion arranged radially outward of the inner cylindrical member and having a straight inner peripheral surface and outer peripheral surface. And a resin-made outer cylinder member provided between the inner cylinder member and the outer cylinder member, at least at one end side in the axial direction and provided with an insertion end portion whose outer peripheral surface is tapered toward the tip. And a cylindrical elastic body portion that elastically connects the inner cylindrical member and the outer cylindrical member, and the outer cylindrical member is press-fitted into the shaft hole of the cylindrical mounting member from the insertion end portion side. In the vibration isolator fixed to the shaft hole, the outer peripheral surface of the outer cylindrical member is straight up to the base of the insertion end, and the inner peripheral side of the insertion end is axial with respect to the inner peripheral surface of the cylindrical portion. located in center side, from the root portion of the insertion end portion to a predetermined position in the axial direction inside along with being thicker than the thickness of the cylindrical portion, the roots The thickness of the predetermined range in the axial direction distally from section also lies in that it is thicker than the thickness of the cylindrical portion.
[0009]
In the invention according to claim 1 configured as described above, when the outer cylinder member is press-fitted into the mounting member, the insertion end portion is squeezed to apply a force toward the insertion end portion radially outward. However, the thickness from the root of the insertion end to a predetermined position on the inner side in the axial direction and the thickness of the predetermined range from the root to the front end in the axial direction are larger than the thickness of the cylindrical portion with straight inner and outer peripheral surfaces. Since the thickness is increased, it is possible to resist the radially outward force applied to the insertion end portion with the root portion as the center, and the deformation of the insertion end portion is suppressed.
[0010]
The structural feature of the invention according to claim 2 is that, in the vibration isolator according to claim 1, the tip of the insertion end is a flat surface . As described above, the tip end surface of the insertion end portion is a flat surface, so that the flat surface is brought into close contact with the wall surface of the molding die when the outer cylinder member is attached to the molding die used for vulcanization molding of the elastic body portion. be able to. Therefore, when the elastic material is injected between the inner cylinder member and the outer cylinder member in the mold, it is possible to reliably prevent leakage from the distal end surface side of the insertion end portion outward .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a vibration isolator interposed between a vehicle body and a suspension according to the embodiment in a sectional view at an axial position. It is. The vibration isolator 10 includes a cylindrical inner cylinder member 11 made of metal such as iron, a cylindrical outer cylinder member 13 made of a thin resin and disposed radially outward and between axial ends. A substantially cylindrical elastic body portion 21 that elastically connects the inner cylinder member 11 and the outer cylinder member 13 is provided. The vibration isolator 10 is attached by press-fitting the outer cylinder member 13 into the shaft hole 32 of the metal attachment member 31 shown in FIG.
[0012]
As shown in FIG. 3, the outer cylinder member 13 includes a cylindrical tube portion 14, an annular outer flange portion 18 that slightly protrudes radially outward along the entire circumferential direction at one axial end thereof, and Are integrated. The cylindrical portion 14 has a cylindrical portion 15 having a straight shape in which both the inner and outer peripheral surfaces are parallel to the axial direction on one end side in the axial direction, and the outer peripheral side is press-fitted into the mounting member 31 at the other end in the axial direction. In order to facilitate this, an insertion end portion 16 is provided that has an inclined surface inclined toward the tip by a predetermined angle θ (for example, 12 ° in this example). The angle of the inclined surface of the insertion end portion 16 is set to 10 ° to 30 ° in order to avoid being caught in the mounting member 31 and being unable to be press-fit while being pressed into the mounting member 31 in consideration of press-fitting properties. It is desirable.
[0013]
The inner peripheral side of the outer cylinder member 13 on the insertion end portion 16 side is located slightly on the axial center side with respect to the inner peripheral surface of the cylindrical portion 15, and is parallel to the axial direction from the tip of the insertion end portion 16. It is a parallel inner wall portion 17a that extends slightly to the axially inner position X from the portion 16a. Furthermore, the inner peripheral side on the insertion end 16 side is an inclined inner wall portion 17b that is inclined at a predetermined angle toward a position Y that is a predetermined distance inward in the axial direction from the position X. 15 is connected. That is, the thickness of the portion from the root portion 16a of the insertion end portion 16 through the position X to the position Y is made thicker than the thickness of the cylindrical portion 15, and further from the root portion 16a of the insertion end portion 16 to the tip in the axial direction. The thickness of the predetermined range on the side is also thicker than the thickness of the cylindrical portion 15. The distal end of the insertion end 16 is a flat surface 16b extending in the direction perpendicular to the axis. However, the flat surface 16b may be inclined with respect to the direction perpendicular to the axis in accordance with the inner surface of the mold. The length of the flat surface 16b in the radial direction is desirably 1 mm or more in order to ensure close contact with the mold. Note that, at the position X and the position Y of the inner peripheral surface, in order to avoid stress concentration, the boundary portion is slightly cut out to have an R shape (curved surface shape).
[0014]
As a resin material of the outer cylinder member 13, it is necessary to have an appropriate strength as the outer cylinder member 13 and to have flexibility to cope with compressive deformation by press-fitting into the mounting member 31, for example. Polyamide 66, polyamide 6 and the like are preferably used. These resin materials are usually further mixed with glass fiber or the like for reinforcement. As a preferred example, a resin material having a Young's modulus of 4300 MPa, a Poisson's ratio of 0.35, and a density of 1.36 can be obtained by mixing about 30% by weight of glass fiber with polyamide 66. The outer cylinder member 13 is mass-produced at low cost by injection molding using these resin materials.
[0015]
Between the inner cylinder member 11 and the outer cylinder member 13, an elastic body portion 21 made of a substantially cylindrical rubber elastic body is provided by vulcanization molding, and the two are elastically connected to each other. The elastic body portion 21 has an annular shape for softening the spring characteristics that are dented in the axial direction along the entire circumference in the circumferential direction from the radial intermediate position to the position in the vicinity of the inner peripheral surface of the outer cylinder member 13 at both axial ends. The currants 22 and 23 are provided. Further, the elastic body portion 21 is integrally provided with an annular stopper portion 24 that protrudes in the axial direction along the entire circumference in the circumferential direction on the axially outer surface side of the outer flange portion 18 of the outer cylinder member 13.
[0016]
The elastic body portion 21 is integrally formed by setting the inner cylinder member 11 and the outer cylinder member 13 in a molding die (not shown) and performing rubber vulcanization molding. At the time of rubber vulcanization molding, the distal end of the insertion end portion 16 is a flat surface 16b. Therefore, when the outer cylinder member 13 is mounted on a molding die used for vulcanization molding of the elastic body portion 21, the flat surface 16b is formed. It can be adhered to the wall surface of the mold. Therefore, when the rubber elastic body material is injected between the inner cylinder member 11 and the outer cylinder member 13 in the mold, leakage from the distal end side of the insertion end portion 16 to the outside can be reliably prevented. As a result, it is possible to prevent molding failure of the elastic body portion due to leakage of the rubber elastic material and avoid waste of the rubber elastic material. As shown in FIG. 4, the vibration isolator 10 thus formed has a stopper member 19 that is a disc-shaped metal fitting having a central hole at the end on the flange portion 18 side of the inner cylinder member 11 coaxially. Fixed.
[0017]
As shown in FIG. 4, the vibration isolator 10 is inserted and fixed to the attachment member 31 by press-fitting the outer cylinder member 20 into the shaft hole 32 of the attachment member 31. The attachment member 31 has a cylindrical shape made of metal, and on both ends in the axial direction of the shaft hole 32, the inner peripheral portion is a chamfered portion 33 that is an inclined surface cut out at a predetermined angle with respect to the shaft center. Yes. The press-fitting of the vibration isolator into the shaft hole 32 is uniformly performed by pressing the stopper member 19 with a pressing jig (not shown).
[0018]
Here, when the outer cylinder member 13 is press-fitted into the mounting member 31, a force is applied to the insertion end 16 to be squeezed and the distal end side to be bent radially outward. Since the thickness of a predetermined range from 16a to position X and the axial front end side is thicker than the thickness of the straight cylindrical portion 15, the radially outward direction applied to the insertion end portion 16 with the root portion 16a as the center Can counteract the power of For this reason, the deformation of the insertion end portion 16 is suppressed, and the problem that the insertion end portion 16 is easily cracked can be solved. Further, since the thickness is increased within a predetermined range on the insertion end portion 16 side of the outer cylinder member 13 and the entire thickness is not increased, the increase in the amount of resin is small as a whole. Therefore, the weight of the outer cylinder member 13 hardly increases and the member cost does not become expensive.
[0019]
In addition, about the thick part of the outer cylinder member 13, although extending in parallel to an axial direction from the root part 16a of the insertion end part 16 to the position X of an axial inner side, it is thickened, it replaces with this. It is good also as an inclined wall part made to incline toward the cylindrical part 15 from a position immediately. Further, the inclined wall portion is not limited to a flat inclined surface but may be a curved inclined surface. In addition, about the said embodiment, it is an example and can change and implement variously in the range which does not deviate from the main point of this invention.
[0020]
【The invention's effect】
According to the first aspect of the present invention, the thickness from the root portion of the insertion end portion to the predetermined position on the inner side in the axial direction is made thicker than the thickness of the cylindrical portion, and the thickness within a predetermined range from the root portion to the distal end side in the axial direction. By making the thickness thicker than the thickness of the cylindrical portion, when the outer cylinder member is press-fitted into the mounting member, a force is applied to the insertion end portion to be squeezed and the distal end side to be bent radially outward. It is possible to counter the radially outward force applied to the insertion end portion around the root portion . Therefore, since the deformation of the insertion end portion is suppressed, it is possible to solve the problem that the insertion end portion is easily cracked. Further, since the thickness of the entire outer cylinder member is not increased, the amount of resin is not increased, so that the weight of the outer cylinder member is hardly increased and the member cost is not increased.
[0021]
Moreover, by making the tip of the insertion end portion a flat surface, it is possible to reliably prevent the elastic material from leaking outward from the tip end side of the insertion end portion, and as a result, the elastic material leaks out. The molding failure of the elastic body portion can be prevented and the waste of the elastic body material can be avoided (effect of the invention of claim 2).
[Brief description of the drawings]
FIG. 1 is a cross-sectional view at an axial position schematically showing a vibration isolator according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view at an axial position showing an attachment member.
FIG. 3 is a cross-sectional view at an axial position showing an outer cylinder member of the vibration isolator.
FIG. 4 is a cross-sectional view at an axial position showing a mounting state of the vibration isolator to a mounting member.
FIG. 5 is a cross-sectional view at an axial position schematically showing a vibration isolator as a conventional example.
FIG. 6 is a cross-sectional view at an axial position schematically showing a vibration isolator as another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Vibration isolator, 11 ... Inner cylinder member, 13 ... Outer cylinder member, 14 ... Tube part, 15 ... Cylindrical part, 16 ... Insertion end part, 16a ... Base part, 16b ... Flat surface, 17a ... Parallel inner wall part, 17b ... Inclined inner wall part, 18 ... Outer flange part, 21 ... Elastic body part, 31 ... Mounting member.

Claims (2)

An inner cylinder member and a cylindrical portion that is disposed radially outward of the inner cylinder member and has an inner peripheral surface and an outer peripheral surface that are straight, and at least one end side in the axial direction is tapered toward the tip. an outer tube member made of resin is provided with the inclined insertion end, is disposed between the inner cylinder member and the outer cylinder member, for connecting the inter-inner cylinder member and the outer tubular member elastically cylinder it and a Jo elastic body, a vibration damping device that is fixed to the shaft hole the outer cylinder member is press-fitted into the axial bore of the tubular attachment member from the insertion end side,
The outer peripheral surface of the outer cylindrical member is straight up to the base of the insertion end, and the inner peripheral side of the insertion end is located on the axial center side with respect to the inner peripheral surface of the cylindrical portion, from the root portion of the insertion end portion to a predetermined position in the axial direction inside, along with being thicker than the thickness of the cylindrical portion, also the thickness of the predetermined range in the axial direction distally from該根source unit meat of the cylindrical portion A vibration isolator characterized by being thicker than the thickness. The anti-vibration device according to claim 1, wherein a distal end of the insertion end portion is a flat surface .

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