JP2015117808A - Cylindrical vibration isolator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical vibration isolator with a new structure which achieves reduction in weight by an outer cylinder member made of synthetic resin, in which a spring constant in a direction perpendicular to an axis is set to be efficiently large and which can advantageously reduce the spring constant in a wrench direction.SOLUTION: A body rubber elastic body 16 is fixed to a large diameter part 18 provided at a middle portion in an axial direction of an inner shaft member 12. On the other hand, an inner surface of an inner peripheral recess part 20 opening to an inner peripheral surface of an outer cylinder member 14 includes an inner taper surface 22 which inclines to the inner peripheral side toward the outside of the axial direction. The body rubber elastic body 16 is fixed to the inner taper surface 22. Furthermore, an inner surface of an outer peripheral recess part 24 opening to an outer peripheral surface of the outer cylinder member 14 includes an outer taper surface 26 which inclines to the outer peripheral side toward the outside of the axial direction. By the outer cylinder member 14 being fitted and inserted into a mounting hole of a vibration isolation connected object member, an axial direction outer end portion of the outer cylinder member 14 is deformed to the inner peripheral side by the outer taper surface 26 being pressed by an inner surface of the mounting hole.

Description

  The present invention relates to a cylindrical vibration isolator used, for example, as an engine mount or a suspension bush of an automobile.

  2. Description of the Related Art Conventionally, a cylindrical vibration isolator is known as a type of anti-vibration coupling body or anti-vibration support body that is interposed between members constituting a vibration transmission system and that mutually anti-vibrates and connects these members. . The cylindrical vibration isolator has a structure in which an outer cylindrical member is extrapolated to an inner shaft member, and the inner shaft member and the outer cylindrical member are elastically connected by a main rubber elastic body. The inner shaft member is attached to one member constituting the vibration transmission system, and the outer cylinder member is fitted and attached to a mounting hole provided in the other member constituting the vibration transmission system.

  By the way, in the cylindrical vibration isolator, for example, in order to achieve both improvement in vehicle maneuverability and stability and realization of excellent riding comfort, the spring constant in the direction perpendicular to the axis is set large, and the spring constant in the twisting direction is set. In some cases, it is required to reduce the value. In such a case, for example, a structure in which a diameter-enlarged portion is provided at the axial center portion of the inner shaft member and diameter reduction processing is applied to both ends in the axial direction of the outer cylinder member made of metal. Is adopted. As a result, the elastic deformation of the main rubber elastic body toward the outside in the axial direction is limited at the time of the input in the direction perpendicular to the axis, and the spring constant in the direction perpendicular to the axis can be set large. It can be set relatively small with respect to the spring constant in the perpendicular direction.

  However, when the outer cylindrical member is formed of a synthetic resin for the purpose of reducing the weight or securing the degree of freedom of shape, it is difficult to reduce the diameter of both ends of the outer cylindrical member in the axial direction. It is difficult to adopt the spring characteristic adjustment method.

  Therefore, in Japanese Patent No. 4533763 (Patent Document 1), as shown in FIG. 2 of Patent Document 1, the outer peripheral surface of the outer tube member made of synthetic resin is moved outwardly in the axial direction. It is set as the curved shape which inclines, and the axial direction both ends of an outer cylinder member deform | transform into an inner peripheral side by inserting an outer cylinder member in a mounting hole. As a result, in the mounting state in the mounting hole, the shape of the inner peripheral surface of both ends in the axial direction of the outer cylinder member is substantially deformed in the same manner as when the diameter reduction processing is performed, and the spring constant in the direction perpendicular to the axis is increased. Increased.

  However, as shown in FIG. 2 of Patent Document 1, in the single state of the cylindrical vibration isolator, when the inner peripheral surface of the outer cylindrical member is a straight cylindrical surface that extends parallel to the central axis, When the outer cylinder member is deformed to the inner peripheral side by fitting into the mounting hole, the main rubber elastic body escapes outward in the axial direction, and the spring constant in the direction perpendicular to the axis is difficult to increase efficiently. Moreover, since the main rubber elastic body is deformed outward in the axial direction when the outer cylinder member is deformed, there is a possibility that the spring characteristics vary and the intended vibration-proof performance cannot be stably obtained.

Japanese Patent No. 4533763

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is to reduce the weight by using an outer cylindrical member made of synthetic resin, and to efficiently set the spring constant in the direction perpendicular to the axis. However, an object of the present invention is to provide a cylindrical vibration isolator having a novel structure that can advantageously reduce the spring constant in the twisting direction.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  That is, according to the first aspect of the present invention, an outer cylinder member made of a synthetic resin is extrapolated with respect to the inner shaft member, and the inner shaft member and the outer cylinder member are elastically connected by the main rubber elastic body. In the cylindrical vibration isolator, a large-diameter portion having a partially increased outer diameter is provided at an axially intermediate portion of the inner shaft member, and the main rubber elastic body is fixed to the large-diameter portion. On the other hand, the outer cylindrical member is provided with an inner peripheral recess that opens to the inner peripheral surface, and an inner tapered surface that gradually slopes toward the inner peripheral side as the inner surface of the inner peripheral recess goes outward in the axial direction. The main rubber elastic body is fixed to the inner tapered surface, and the outer cylindrical member is provided with an outer peripheral recess that opens to the outer peripheral surface, and the inner surface of the outer peripheral recess gradually increases in the axial direction. It has an outer tapered surface that inclines toward the outer periphery, When the outer cylindrical member is fitted into the mounting hole of the vibration-proof connection target member, the outer tapered surface of the outer cylindrical member is pressed by the inner peripheral surface of the mounting hole, and the outer end portion in the axial direction of the outer cylindrical member Is characterized by being deformed to the inner peripheral side.

  According to the cylindrical vibration isolator having the structure according to the first aspect, since the outer cylindrical surface is provided with the outer tapered surface, the outer cylindrical member is attached to the vibration isolation connection target member. By fitting into the hole, the outer end portion in the axial direction of the outer cylinder member is deformed to the inner peripheral side. As a result, the axially outer end portion of the main rubber elastic body is fastened to the inner peripheral side by the outer cylinder member, and the outer elastic deformation of the main rubber elastic body outwardly in the axial direction is deformed to the inner peripheral side. Since it is restrained by being restrained by the cylindrical member, the spring constant in the direction perpendicular to the axis of the main rubber elastic body is set large. On the other hand, since the main rubber elastic body is fixed between the large diameter portion of the inner shaft member and the inner peripheral concave portion of the outer cylindrical member, the shear spring component dominates in the main rubber elastic body against the input in the twisting direction. Therefore, an increase in the spring constant due to the deformation restriction of the main rubber elastic body is suppressed. With these, the spring constant in the direction perpendicular to the axis of the main rubber elastic body can be set large, and the spring constant in the twisting direction can be set relatively small with respect to the spring constant in the direction perpendicular to the axis. A large degree of freedom is secured.

  Furthermore, since an inner peripheral recess having an inner tapered surface is formed on the inner peripheral surface of the outer cylindrical member, when the axially outer end portion of the outer cylindrical member is deformed to the inner peripheral side, the main rubber elastic body Elastic deformation outward in the axial direction is restricted by the inner tapered surface. Accordingly, the spring in the direction perpendicular to the axis of the main rubber elastic body can be increased more efficiently by the deformation of the outer cylindrical member, and the spring in the twisting direction can be relative to the spring constant in the direction perpendicular to the axis. In addition, the deformation mode of the main rubber elastic body can be stabilized, and the desired vibration isolation characteristics can be stably obtained.

  In addition, since the inner tapered surface is formed in advance on the outer cylindrical member, it is possible to effectively deform the main rubber elastic body outward in the axial direction even at the initial stage of deformation when the amount of deformation of the outer cylindrical member toward the inner peripheral side is small. Can be limited to. Therefore, it is possible to set the spring constant in the direction perpendicular to the axis more efficiently and to make the spring constant in the twisting direction relatively smaller than the spring constant in the direction perpendicular to the axis, and to achieve a desired vibration isolation characteristic. It can be obtained more stably.

  In addition, since the inner shaft member is provided with a large diameter portion, even if an inner peripheral recess is formed in the inner peripheral surface of the outer cylindrical member, the free length in the direction perpendicular to the axis of the main rubber elastic body is The spring in the direction perpendicular to the axis can be set hard by avoiding an unnecessarily large size in the axial middle part. In addition, by preventing the free length of the main rubber elastic body in the direction perpendicular to the axis from being significantly different between the axial middle portion and the two axial end portions, the concentrated action of stress on the axial end portions of the main rubber elastic body Is avoided, and durability is improved.

  According to a second aspect of the present invention, in the cylindrical vibration isolator described in the first aspect, an outer peripheral surface of the large-diameter portion of the inner shaft member is a spherical curved convex surface, and the mounting hole The inner surface of the inner peripheral recess of the inserted outer cylinder member is an annular curved concave surface that is continuous over the entire circumference in a curved cross section corresponding to the outer peripheral surface of the large diameter portion, and the outer peripheral surface of the large diameter portion. And the inner surface of the inner circumferential recess are arranged opposite to each other.

  According to the second aspect, the main rubber elastic body is less likely to be compressed between the inner shaft member and the outer cylindrical member with respect to the input in the twisting direction, and the shear deformation of the main rubber elastic body is more dominant. Therefore, the spring constant in the twisting direction can be set smaller.

  Further, since the inner surface of the inner peripheral recess of the outer cylinder member is an annular curved concave surface, when the outer cylinder member is deformed by fitting into the mounting hole, the stress on the inner surface of the inner peripheral recess is distributed. Improved durability is achieved.

  According to a third aspect of the present invention, in the cylindrical vibration isolator described in the first or second aspect, an annular curve in which an inner surface of the outer peripheral recess of the outer cylindrical member is continuous over the entire circumference in a curved cross section. It is a concave surface.

  According to the third aspect, since the inner surface of the outer peripheral concave portion of the outer cylindrical member has a curved cross section and extends in the circumferential direction, the inner surface of the outer peripheral concave portion is deformed when the outer cylindrical member is deformed by fitting into the mounting hole. As a result, the stress can be dispersed and the durability can be improved.

  According to a fourth aspect of the present invention, in the cylindrical vibration isolator described in any one of the first to third aspects, the inner peripheral recess is formed over the entire axial direction of the outer cylindrical member. In addition, the inner peripheral surface of both end portions in the axial direction of the outer cylindrical member is formed by the inner tapered surface, and the outer peripheral concave portion is formed over the entire axial direction of the outer cylindrical member. The outer peripheral surface of the axial direction both ends of a member is comprised by the said outer taper surface.

  According to the fourth aspect, since the inner peripheral recess is formed over the entire axial direction of the outer cylinder member, the entire outer peripheral surface of the main rubber elastic body is fixed to the inner surface of the inner peripheral recess, The axial end edge of the outer peripheral surface of the main rubber elastic body is fixed to the inner tapered surface. As a result, it is possible to secure a large fixing area for the outer rubber member of the main rubber elastic body to obtain a high fixing strength, and to effectively limit the elastic deformation of the main rubber elastic body in the axially outward direction. Thus, both a high spring in the direction perpendicular to the axis and a low spring in the twisting direction are advantageously realized.

  Further, since the outer peripheral recess is formed over the entire axial direction of the outer cylindrical member, the inclination angle of the inner surface of the outer peripheral recess can be set small while ensuring the depth of the outer peripheral recess. Therefore, the outer cylinder member can be sufficiently deformed by being mounted in the mounting hole, and the local deformation of the outer cylinder member is prevented, and the predetermined deformation is stabilized while avoiding damage to the outer cylinder member. Can be realized.

  According to a fifth aspect of the present invention, in the cylindrical vibration isolator described in any one of the first to fourth aspects, a depth dimension of the inner peripheral recess is larger than a depth dimension of the outer peripheral recess. It is what has been.

  According to the fifth aspect, the outer peripheral end of the main rubber elastic body fixed to the inner surface of the inner peripheral recess is deformed outward in the axial direction by setting the depth dimension of the inner peripheral recess to be large. The spring constant in the direction perpendicular to the axis can be set large, and the spring constant in the twisting direction can be made relatively small with respect to the spring constant in the direction perpendicular to the axis.

  Further, since the depth dimension of the outer peripheral recess is set smaller than that of the inner peripheral recess, the outer cylindrical member can be deformed by deformation of the outer cylindrical member without unnecessarily increasing the amount of deformation of the outer cylindrical member due to fitting into the mounting hole. Can be brought into contact with the inner peripheral surface of the mounting hole. Thereby, the outer cylinder member can be fitted into the mounting hole in a wide range in the axial direction, and the mounting strength of the outer cylinder member to the mounting hole can be ensured. Furthermore, since the outer cylinder member is restrained by the inner peripheral surface of the mounting hole, the deformation of the outer cylinder member at the time of vibration input is reduced, and the durability of the outer cylinder member is also improved. Preferably, substantially the entire outer peripheral surface of the outer cylinder member is superimposed on the inner peripheral surface of the mounting hole in the mounting state in the mounting hole.

  According to a sixth aspect of the present invention, in the cylindrical vibration damping device according to any one of the first to fifth aspects, an inclination angle of the inner tapered surface is larger than an inclination angle of the outer tapered surface. It is what.

  According to the sixth aspect, since the inclination angle of the inner tapered surface is set to be large, deformation of the main rubber elastic body in the axial direction outer side is more effectively limited by the inner tapered surface, and the direction perpendicular to the axis The spring constant in the twisting direction can be made relatively small with respect to the spring constant in the direction perpendicular to the axis.

  Further, since the inclination angle of the outer tapered surface is set smaller than the inclination angle of the inner tapered surface, the outer cylindrical member is effectively deformed to the inner peripheral side due to the fitting into the mounting hole, and the shaft The spring constant in the perpendicular direction can be set large, and the spring constant in the twisting direction can be made relatively small with respect to the spring constant in the axial perpendicular direction. Further, the outer tapered surface is easily brought into contact with the inner peripheral surface of the mounting hole in the mounting state in the mounting hole, and the outer cylindrical member is constrained by the inner peripheral surface of the mounting hole in a wide range. The durability of the member can be improved and the mounting state can be stabilized.

  According to a seventh aspect of the present invention, in the cylindrical vibration isolator described in any one of the first to sixth aspects, the main rubber elastic body is fixed to the outer peripheral surface of the inner shaft member. The outer cylinder member is injection-molded on the outer peripheral side of the main rubber elastic body, and the main rubber elastic body is pre-compressed by the injection molding pressure of the outer cylinder member.

  According to the seventh aspect, since the main rubber elastic body is precompressed in the direction perpendicular to the axis by the injection molding pressure of the outer cylinder member to be molded later, the spring in the direction perpendicular to the axis is set large and The direction spring can be made relatively small with respect to the spring constant in the direction perpendicular to the axis. In particular, the injection molding pressure of the outer cylinder member is exerted in the normal direction with respect to each portion of the outer peripheral surface of the main rubber elastic body. Therefore, since the portion fixed to the inner tapered surface of the main rubber elastic body is pre-compressed inward in the axial direction, the deformation of the main rubber elastic body outward in the axial direction is more effectively limited. The spring in the direction perpendicular to the axis can be set larger.

  In addition, since the outer peripheral surface of the main rubber elastic body has a predetermined shape, the inner peripheral surface of the outer cylinder member having the inner peripheral recess can be formed into a predetermined shape without requiring a mold. Demolding failure due to cutting can be avoided.

  According to the present invention, the inner circumferential recess having the inner tapered surface is formed on the inner circumferential surface of the outer cylinder member, and the outer circumferential recess having the outer taper surface is formed on the outer circumferential surface of the outer cylinder member. Therefore, the deformation of the main rubber elastic body in the axially outward direction can be effectively limited by fitting the outer cylinder member into the mounting hole. On the other hand, since the main rubber elastic body is fixed between the large-diameter portion of the inner shaft member and the inner peripheral recess of the outer cylindrical member, the spring constant can be reduced by the shear spring component with respect to the input in the twisting direction. . Therefore, the spring constant in the direction perpendicular to the axis can be set large, and the spring constant in the twisting direction can be set relatively small relative to the spring constant in the direction perpendicular to the axis. Can be greatly obtained.

  In addition, since the inner shaft member is provided with the large-diameter portion, the free length of the main rubber elastic body is unnecessarily large in the axially intermediate portion in the structure in which the inner circumferential recess is formed in the outer cylindrical member. And a large spring constant in the direction perpendicular to the axis can be obtained.

The longitudinal cross-sectional view which shows the suspension bush as one Embodiment of this invention. The longitudinal cross-sectional view which shows the vehicle mounting state of the suspension bush shown in FIG. The longitudinal cross-sectional view which shows the attachment process to the mounting hole of the suspension bush shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a suspension bush 10 for an automobile as an embodiment of a cylindrical vibration isolator having a structure according to the present invention. The suspension bushing 10 has a structure in which an outer cylinder member 14 is externally arranged with respect to the inner shaft member 12, and the inner shaft member 12 and the outer cylinder member 14 are elastically connected by a main rubber elastic body 16. . In the following description, the vertical direction refers to the vertical direction in FIG. 1 that is the vertical vertical direction when the vehicle is mounted unless otherwise specified.

  More specifically, the inner shaft member 12 has a substantially cylindrical shape with a small diameter, and is formed of a metal such as iron or an aluminum alloy. In addition, a large-diameter portion 18 that protrudes toward the outer peripheral side is integrally formed at the axially central portion of the inner shaft member 12. The large-diameter portion 18 is formed by partially expanding the pipe-shaped inner shaft member 12 by bulging, and in this embodiment, the inner-diameter dimension and the outer-diameter dimension of the inner shaft member 12 in the large-diameter portion 18. Are all larger. Furthermore, in this embodiment, the outer peripheral surface of the large-diameter portion 18 is a spherical curved convex surface that is convex on the outer peripheral side, and has a smooth shape with no break points or broken lines.

  The outer cylinder member 14 has a substantially cylindrical shape having a larger diameter than the inner shaft member 12 and is formed of a hard synthetic resin. The material for forming the outer cylinder member 14 is not particularly limited as long as it is a hard synthetic resin. For example, polyamide (hereinafter referred to as PA) 46, PA6, PA66, PA92, PA99, PA610, PA612, PA11, PA912, PA12, a copolymer of PA6 and PA66, a copolymer of PA6 and PA12, PA4T, PA6T, PAMXD6, PA9T, PA10T, PA11T, PA12T, PA13T and the like can be suitably employed. In particular, as a material for forming the outer cylinder member 14, PA66 having excellent hydrolysis resistance is desirable. In addition, said forming material can be employ | adopted individually or in combination of 2 or more types. Further, the strength can be increased by adding glass fiber or the like to the above synthetic resin material. The material for forming the outer cylinder member 14 is not limited to the thermoplastic synthetic resin, and a thermosetting synthetic resin can also be adopted.

  Further, the outer cylindrical member 14 is formed with an inner peripheral recess 20 that opens to the inner peripheral surface. The inner circumferential recess 20 is a recess having an annular curved concave surface that is continuous over the entire circumference in a substantially arc-shaped curved cross section, and the depth dimension gradually increases toward the center in the axial direction. Further, in the present embodiment, the inner peripheral recess 20 is formed over the entire axial length of the outer cylinder member 14, and the entire inner peripheral surface of the outer cylinder member 14 is configured by the inner surface of the inner peripheral recess 20. . Furthermore, the inner surface of the inner peripheral recess 20 is provided with inner tapered surfaces 22 and 22 that gradually incline toward the inner periphery as it goes outward in the axial direction, and includes both axial end portions of the inner surface of the inner peripheral recess 20. The whole is composed of inner tapered surfaces 22 and 22.

  Furthermore, the outer cylinder member 14 is formed with an outer peripheral recess 24 that opens to the outer peripheral surface. The outer peripheral recess 24 is a recess having an annular curved concave surface that is continuous over the entire circumference in a substantially arc-shaped curved cross section, and the depth dimension gradually increases toward the center in the axial direction. Further, in the present embodiment, the outer peripheral recess 24 is formed over the entire axial length of the outer cylindrical member 14, and the entire outer peripheral surface of the outer cylindrical member 14 is configured by the inner surface of the outer peripheral recess 24. Furthermore, the inner surface of the outer peripheral recess 24 is provided with outer tapered surfaces 26 and 26 that gradually incline toward the outer periphery as it goes outward in the axial direction. The outer tapered surfaces 26, 26 are used. In addition, the outer cylinder member 14 is gradually thinned toward the center in the axial direction by forming the inner peripheral recess 20 and the outer peripheral recess 24.

In the outer cylindrical member 14 of the present embodiment, the depth dimension (d ₁ ) of the inner peripheral recess 20 is larger than the depth dimension (d ₂ ) of the outer peripheral recess 24 (d ₁ > d ₂ ). The inner taper surface 22 and the outer taper surface 26 are formed with substantially the same axial dimension, and the curvature of the inner taper surface 22 is larger than the curvature of the outer taper surface 26. The angle (θ ₁ ) is larger than the inclination angle (θ ₂ ) of the outer tapered surface 26 (θ ₁ > θ ₂ ). Note that θ ₁ is an average value of the inclination angle of the inner tapered surface 22, and θ ₂ is an average value of the inclination angle of the outer tapered surface 26.

  The end surfaces 28, 28 on both sides in the axial direction of the outer cylinder member 14 are respectively flat surfaces extending in a direction substantially perpendicular to the axis, and extend in a circumferential annular shape with a substantially constant radial width dimension. Moreover, in this embodiment, the curvature of the inner taper surface 22 is made smaller than the curvature of the large diameter part 18 of the inner shaft member 12 in the longitudinal cross section shown in FIG.

  Then, in a state where the outer cylinder member 14 is extrapolated to the inner shaft member 12, the inner bush member 10 and the outer cylinder member 14 are elastically connected by the main rubber elastic body 16, whereby the suspension bush 10 is formed. Yes. The main rubber elastic body 16 has a substantially cylindrical shape as a whole, the inner peripheral surface is vulcanized and bonded to the outer peripheral surface of the inner shaft member 12, and the outer peripheral surface is connected to the inner peripheral surface of the outer cylindrical member 14. It is fixed. The main rubber elastic body 16 is fixed so as to cover the entire large-diameter portion 18 of the inner shaft member 12, and is fixed to substantially the entire inner tapered surfaces 22, 22 of the outer cylinder member 14.

  In the present embodiment, after the main rubber elastic body 16 is vulcanized and formed on the outer periphery of the inner shaft member 12, the outer cylinder member 14 is injection-molded on the outer periphery of the main rubber elastic body 16 so that the suspension bush 10 is Is formed. As a result, the inner peripheral recess 20 that opens to the inner peripheral surface of the outer cylindrical member 14 is formed without causing difficulty in die-cutting due to undercutting, and the main rubber elasticity is increased by the injection molding pressure of the outer cylindrical member 14. The body 16 is pre-compressed in the direction perpendicular to the axis. In particular, since the inner peripheral recess 20 of the outer cylindrical member 14 has inner tapered surfaces 22 and 22 formed on the inner surface, the main rubber elastic body 16 is also pre-compressed in the axial direction.

  Further, the end portions 30 in the axial direction of the main rubber elastic body 16 are respectively formed with curls 30. The straight 30 is a groove-like recess that opens in the axial end surface of the main rubber elastic body 16 and continuously extends in the circumferential direction. The inner surface on the outer peripheral side of the straight 30 is a cylindrical surface that extends substantially parallel to the axial direction, and the radial position is substantially the same as the axial outer end of the outer cylinder member 14.

  As shown in FIG. 2, the suspension bush 10 having such a structure is attached to a vehicle suspension mechanism (not shown). That is, an inner bracket 32 having a substantially U-shaped cross section fixed to a suspension member (not shown) is superimposed on both axial end surfaces of the inner shaft member 12, and mounting bolts 34 and nuts 35 inserted through the inner shaft member 12. The inner shaft member 12 is attached to the vehicle body side by being fixed by bolts. On the other hand, the outer cylinder member 14 is attached to the wheel side by fitting the outer cylinder member 14 into a mounting hole 38 of an arm eye 36 provided in an upper arm or a torsion link as a vibration isolation connection target member.

  Here, as shown in FIG. 2, the outer cylinder member 14 is fitted and attached to the mounting hole 38 in a state where both end portions in the axial direction are deformed to the inner peripheral side. That is, the outer diameter dimension of the outer end of the outer cylinder member 14 in the axial direction is larger than the inner diameter dimension of the mounting hole 38, and when the outer cylinder member 14 is fitted into the mounting hole 38 as shown in FIG. The outer tapered surface 26 of the outer cylindrical member 14 is pressed against the inner peripheral surface of the mounting hole 38, so that both end portions in the axial direction of the outer cylindrical member 14 are pushed into the inner peripheral side and deformed. For example, as shown by a two-dot chain line in FIG. 3, by using a tapered guide jig 40 or the like, the outer end portion of the outer cylindrical member 14 having a larger diameter than the mounting hole 38 is attached to the mounting hole 38. It is possible to guide and fit into the mounting hole 38 while reducing the diameter to the inner diameter or less.

  As a result, the deformation of the main rubber elastic body 16 in the axially outward direction is limited by the axially opposite ends of the outer cylindrical member 14, and the spring constant in the direction perpendicular to the axis is set large. Is set relatively small with respect to the spring constant in the direction perpendicular to the axis. Moreover, since the inner peripheral recess 20 having the inner tapered surfaces 22, 22 is formed on the inner peripheral surface of the outer cylindrical member 14, the shaft of the main rubber elastic body 16 can be used even before the outer cylindrical member 14 is deformed. Deformation outward in the direction is limited in advance, and the desired spring characteristics can be stably obtained by reducing variations in the deformation mode of the main rubber elastic body 16.

In particular, in the present embodiment, the depth dimension (d ₁ ) of the inner peripheral recess 20 is larger than the depth dimension (d ₂ ) of the outer recess 24, so that the outer side of the main rubber elastic body 16 is axially outward. The inner peripheral recess 20 is effectively limited by the inner peripheral recess 20 while the inner surface of the outer peripheral recess 24 is overlapped with the inner peripheral surface of the mounting hole 38 so as to stabilize the mounting state and improve durability. It has been.

Further, the inclination angle (θ ₁ ) of the inner tapered surface 22 is made larger than the inclination angle (θ ₂ ) of the outer tapered surface 26. Thereby, the deformation of the main rubber elastic body 16 in the axially outward direction is effectively limited by the inner tapered surfaces 22, 22, and the local large deformation of the outer cylindrical member 14 due to the attachment to the mounting hole 38 is avoided. As a result, durability is improved.

  Further, since the outer tapered surface 26 is inclined toward the outer peripheral side as going outward in the axial direction, the outer tapered surface 26 is brought into contact with the inner peripheral surface of the mounting hole 38 having a cylindrical shape extending in the axial direction. As a result, the outer end portion of the outer cylindrical member 14 in the axial direction is deformed more toward the inner peripheral side as it goes outward in the axial direction. Accordingly, the inner tapered surfaces 22 and 22 are bent so that the curvature in the longitudinal section becomes smaller due to the deformation of the outer cylindrical member 14. In addition, in the mounting state of the suspension bush 10 shown in FIG. 2 on the vehicle, the curvature of the inner tapered surfaces 22 and 22 is reduced, so that the inner tapered surfaces 22 and 22 are large in the inner shaft member 12 in the present embodiment. The inner conical surfaces 22 and 22 and the outer peripheral surface of the large-diameter portion 18 are arranged so as to face each other.

  In the present embodiment, when the outer cylinder member 14 is fitted into the mounting hole 38, the end surfaces 28, 28 of the outer cylinder member 14 are gradually inclined inward in the axial direction toward the inner peripheral side. Thereby, the angle of the inner peripheral edge of the outer cylinder member 14 is ensured to be relatively large, so that the durability of the outer cylinder member 14 is improved and the load resistance of the outer cylinder member 14 with respect to the input in the direction perpendicular to the axis. Improvements can be achieved.

  As described above, the outer cylindrical member 14 is deformed by fitting into the mounting hole 38, whereby the outer peripheral end portion of the main rubber elastic body 16 is limited by the inner tapered surfaces 22 and 22 in the axially outward deformation. Thus, the spring in the direction perpendicular to the axis of the main rubber elastic body 16 is set large. On the other hand, the outer peripheral surface of the large-diameter portion 18 of the inner shaft member 12 is a spherical curved convex surface, and the inner surface of the inner peripheral concave portion 20 of the outer cylinder member 14 is an annular curved concave surface corresponding to the outer peripheral surface of the large-diameter portion 18. For this reason, the compression spring component in the main rubber elastic body 16 is reduced at the time of inputting in the twisting direction, and the spring in the twisting direction is made relatively small with respect to the spring constant in the direction perpendicular to the axis. As a result, the degree of freedom in tuning the spring characteristics of the suspension bush 10 is increased, and the desired vibration-proof performance and support performance can be advantageously realized.

  Furthermore, since both axial ends of the outer peripheral end of the main rubber elastic body 16 are compressed in the direction perpendicular to the axis by deformation of the outer cylindrical member 14 toward the inner circumference, a large spring in the direction perpendicular to the axis can be obtained. it can. In addition, in this embodiment, since the outer cylinder member 14 is formed on the outer periphery of the main rubber elastic body 16, the main rubber elastic body 16 is pre-compressed in the direction perpendicular to the axis by the injection molding pressure of the outer cylinder member 14, The spring perpendicular to the axis can be set larger, and the durability is improved.

  Furthermore, since the inner surface of the outer peripheral concave portion 24 of the outer cylindrical member 14 is an annular curved concave surface that is continuous over the entire circumference in a curved cross section, when the outer cylindrical member 14 is deformed, stress is dispersed in the axial direction. As a result, the durability of the outer cylinder member 14 is improved.

  Further, in the present embodiment, the inner peripheral recess 20 and the outer peripheral recess 24 are respectively formed in the entire axial direction of the outer cylindrical member 14, and the inner peripheral surface of the axial end of the outer cylindrical member 14 is the inner tapered surface 22. In addition, the outer peripheral surface of the axial end portion of the outer cylinder member 14 is configured by an outer tapered surface 26. The depth dimension of the inner peripheral recess 20 can be set efficiently large, and the inclination angle of the inner surface of the outer peripheral recess 24 can be set small, so that the inner surface of the outer peripheral recess 24 contacts the inner peripheral surface of the mounting hole 38 in a wider range. It becomes easy. Moreover, since the inner and outer tapered surfaces 22 and 26 are set at the axial end of the outer cylindrical member 14, the main rubber elastic body 16 can be secured while securing the fixing area of the main rubber elastic body 16 to the outer cylindrical member 14. Axial outward deformation is effectively limited by the inner and outer tapered surfaces 22, 26.

  Further, since the bevel 30 is formed at both axial end portions of the main rubber elastic body 16, both axial end portions of the main rubber elastic body 16 are deformed toward the inner peripheral side of the outer cylindrical member 14. It is prevented from being tightened locally and durability is ensured.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the inner peripheral recesses and the inner surfaces of the outer peripheral recesses do not necessarily have to be curved as a whole, and may be configured, for example, by combining shapes extending linearly in the longitudinal section. Further, the inner tapered surface that constitutes the inner surface of the inner circumferential recess and the outer tapered surface that constitutes the inner surface of the outer circumferential recess are not limited to curved shapes in which the inclination angle gradually changes in the axial direction, but are substantially in the axial direction. It may have a shape that spreads at a constant inclination angle.

  Further, the inner peripheral recess and the outer peripheral recess need not be formed in the entire axial direction of the outer cylinder member, and may be formed partially. Specifically, for example, at least one of the inner peripheral concave portion and the outer peripheral concave portion is partially formed in the axially intermediate portion of the outer cylindrical member, and the inner peripheral surface and the outer peripheral surface at the axial end portion of the outer cylindrical member. A straight portion extending substantially parallel to the axial direction can be set on at least one of the above.

  Further, the inner diameter dimension of the inner shaft member is made constant, for example, the middle portion in the axial direction of the inner shaft member 12 is partially thickened, so that the large diameter portion may be formed or substantially constant. By fixing a separate stopper member to the axially intermediate portion of the small-diameter cylindrical pipe having the inner and outer diameter dimensions, the inner shaft member having the large-diameter portion can be formed in two parts.

  Further, the outer peripheral surface of the large diameter portion does not necessarily have to be a spherical curved convex surface, and for example, the outer peripheral surface of the large diameter portion may be cylindrical.

  In addition, a guide taper that is gradually reduced in diameter toward the outer side in the axial direction is set on the outer peripheral surface of at least one axial end portion of the outer cylindrical member, and the outer cylindrical member outside the axial direction of the outer cylindrical member in which the guide taper is set is set. A structure in which the outer diameter dimension is smaller than the inner diameter dimension of the mounting hole at the end can also be adopted. According to this, it becomes easy to fit the outer cylinder member into the mounting hole, and the mounting work of the cylindrical vibration isolator to the vehicle is facilitated. In addition, the inner and outer peripheral corners of the axial end portions of the outer cylinder member may be chamfered.

  The scope of application of the present invention is not limited to the suspension bush, but can be applied to an engine mount, a subframe mount, a body mount, a differential mount, and the like. Furthermore, the present invention is not only applied to a fluid-filled vibration isolator for automobiles, but also suitably applied to motorcycles, railway vehicles, industrial vehicles, and the like.

10: Suspension bush (cylindrical vibration isolator), 12: Inner shaft member, 14: Outer cylinder member, 16: Rubber elastic body of main body, 18: Large diameter portion, 20: Inner peripheral recess, 22: Inner tapered surface, 24 : Outer peripheral recess, 26: outer tapered surface, 36: arm eye, 38: mounting hole

Claims (7)

In the cylindrical vibration isolator in which the outer cylindrical member made of synthetic resin is extrapolated to the inner shaft member, and the inner shaft member and the outer cylindrical member are elastically connected by the main rubber elastic body,
While the inner shaft member is provided with a large-diameter portion whose outer diameter is partially increased in the axially intermediate portion, the main rubber elastic body is fixed to the large-diameter portion,
The outer cylinder member is provided with an inner peripheral recess that opens to the inner peripheral surface, and an inner tapered surface that gradually slopes toward the inner periphery as the inner surface of the inner peripheral recess goes outward in the axial direction. The main rubber elastic body is fixed to the inner tapered surface,
The outer cylindrical member is provided with an outer peripheral concave portion that opens to the outer peripheral surface, and an outer tapered surface that is gradually inclined toward the outer peripheral side as the inner surface of the outer peripheral concave portion goes outward in the axial direction. The outer cylindrical surface of the outer cylindrical member is pressed by the inner peripheral surface of the mounting hole by being fitted into the mounting hole of the vibration proof connection target member, and the axially outer end portion of the outer cylindrical member is the inner peripheral side. A cylindrical vibration isolator characterized by being deformed into a cylindrical shape.   The outer peripheral surface of the large-diameter portion of the inner shaft member is a spherically curved convex surface, and the inner surface of the inner peripheral concave portion of the outer cylindrical member fitted in the mounting hole corresponds to the outer peripheral surface of the large-diameter portion. The cylindrical shape according to claim 1, wherein the curved curved cross section is an annular curved concave surface continuous over the entire circumference, and the outer peripheral surface of the large-diameter portion and the inner surface of the inner peripheral concave portion are arranged to face each other. Anti-vibration device.   The cylindrical vibration isolator according to claim 1 or 2, wherein an inner surface of the outer peripheral concave portion of the outer cylindrical member is an annular curved concave surface that is continuous over the entire circumference in a curved cross section.   The inner circumferential recess is formed over the entire axial direction of the outer cylinder member, the inner circumferential surfaces of both axial end portions of the outer cylinder member are formed by the inner tapered surfaces, and the outer circumferential depression is The outer cylinder member is formed over the entire axial direction of the outer cylinder member, and the outer peripheral surface of each axial end portion of the outer cylinder member is configured by the outer tapered surface. Cylindrical anti-vibration device.   The cylindrical vibration isolator as described in any one of Claims 1-4 with which the depth dimension of the said inner peripheral recessed part is made larger than the depth dimension of the said outer peripheral recessed part.   The cylindrical vibration isolator according to any one of claims 1 to 5, wherein an inclination angle of the inner tapered surface is larger than an inclination angle of the outer tapered surface.   The main rubber elastic body is fixed to the outer peripheral surface of the inner shaft member, and the outer cylinder member is injection-molded on the outer peripheral side of the main rubber elastic body. The cylindrical vibration isolator according to any one of claims 1 to 6, which is pre-compressed by an injection molding pressure.

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