JP5396252B2 - Cylindrical vibration isolator - Google Patents

Description

  The present invention relates to a cylindrical vibration isolator applied to a subframe bush or the like of an automobile.

  2. Description of the Related Art Conventionally, a cylindrical vibration isolator is known as a type of a vibration isolator that is interposed between members constituting a vibration transmission system and that anti-vibrates and connects these members. The cylindrical vibration isolator has a structure in which an inner shaft fitting and an outer cylinder fitting arranged concentrically are connected by a main rubber elastic body, for example, as disclosed in JP-A-4-25628 (Patent Document 1). That is what it is.

  By the way, in such a cylindrical vibration isolator, there are cases in which different spring characteristics are required in the axial direction and in the direction perpendicular to the axis due to differences in main input vibrations and differences in required performance. For example, an automobile sub-frame bush is required to secure support spring rigidity in the axial direction and to improve vibration insulation in a direction perpendicular to the axis.

  However, in the cylindrical vibration isolator, since the main rubber elastic body is interposed between the radially opposing surfaces of the inner shaft bracket and the outer cylinder bracket, it is compressed and deformed against vibration input in the direction perpendicular to the axis. Becomes dominant and the spring tends to become stiff. On the other hand, since shear deformation becomes dominant with respect to vibration input in the axial direction, the spring tends to be soft, and tuning of the spring characteristics in the axial direction and the spring characteristics in the direction perpendicular to the axis is difficult.

  In addition, it has also been proposed that the spring in the direction perpendicular to the axis is set soft by providing a recess or a through hole-shaped curl to the main rubber elastic body. However, if the tickling is small, it is not sufficient to set the spring in the direction perpendicular to the axis soft. On the other hand, if a large tickling is provided, the spring in the axial direction may become unacceptably soft. It was difficult to properly tune the spring ratio in the direction perpendicular to the axis.

Japanese Patent Laid-Open No. 4-25628

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is a simple structure of hard spring characteristics required in the axial direction and soft spring characteristics required in the direction perpendicular to the axis. It is an object of the present invention to provide a cylindrical vibration isolator having a novel structure that can be realized at the same time.

According to a first aspect of the present invention, in the cylindrical vibration damping device in which the outer cylindrical member is spaced apart on the outer peripheral side of the inner shaft member, and the inner shaft member and the outer cylindrical member are connected by a main rubber elastic body, A pair of straight holes penetrating the main rubber elastic body in the axial direction are formed on both sides in the direction perpendicular to the axis across the inner shaft member, and the main rubber elastic body is divided in the circumferential direction by the pair of straight holes. A pair of elastic connecting portions are provided, the axial dimensions on both sides in the circumferential direction of each elastic connecting portion are smaller than the center in the circumferential direction , and the pair of elastic connecting portions are on both sides in the circumferential direction. It has a stepped shape in the circumferential direction in which the axial dimension is reduced with a stepped surface .

  In the cylindrical vibration isolator having the structure according to the first aspect as described above, by changing the axial dimension of the elastic connecting portion that connects the inner shaft member and the outer cylindrical member in the circumferential direction, the spring in the direction perpendicular to the axis is obtained. The spring in the axial direction can be freely adjusted while maintaining the same, and both the hard spring characteristics required in the axial direction and the soft spring characteristics required in the direction perpendicular to the axis are realized effectively. I can do it.

  That is, the elastic connecting portion includes not only a central portion in the circumferential direction in which a sufficiently large axial dimension is ensured, but also a portion protruding on both sides in the circumferential direction. Therefore, it is possible to secure a large rubber volume of the elastic connecting portion that connects the inner shaft member and the outer cylindrical member, and it is possible to efficiently set the spring characteristics in the axial direction of the elastic connecting portion.

  On the other hand, the part which protrudes in the circumferential direction both sides in an elastic connection part is formed in the axial direction dimension small compared with the circumferential direction center part. Therefore, it is possible to reduce the stiffness of the elastic connection portion in the direction perpendicular to the axis due to extending the elastic connection portion on both sides in the circumferential direction. The spring ratio can be adjusted with a high degree of freedom.

In addition, both circumferential portions provided in the elastic connecting portion in order to realize hard spring characteristics in the axial direction deviate from the main load acting position in the circumferential direction in the circumferential direction. Therefore, when the elastic coupling portion is elastically deformed by the vibration input in the direction perpendicular to the axis, the shear component increases in the circumferential side portions as compared with the circumferential center portion. As a result, the spring characteristics in the direction perpendicular to the axis are sufficiently softer in the circumferentially opposite side portions of the elastic connecting portion than in the circumferentially central portion where the compression component is dominant. Therefore, it is possible to prevent the spring characteristics in the direction perpendicular to the axis from becoming stiff by extending the elastic connecting part to both sides in the circumferential direction, and the ratio between the spring in the axis direction and the spring in the direction perpendicular to the axis can be greatly increased. It becomes possible to tune in degrees.
Further, according to the first aspect, the axial dimension of the portion near the center in the circumferential direction where the compression component becomes relatively large when vibration in the direction perpendicular to the axis is input in both circumferential portions can be set sufficiently small. . Therefore, by providing both circumferential portions, it is possible to more effectively suppress the spring characteristics in the direction perpendicular to the axis from becoming hard, and to increase the degree of freedom in tuning the spring ratio.

  According to a second aspect of the present invention, in the cylindrical vibration damping device described in the first aspect, an inner flange is formed at one end portion in the axial direction of the outer cylindrical member, and the main rubber elastic body The pair of elastic connecting portions is fixed to the inner flange.

  According to the second aspect, since the elastic connecting portion is fixed to the inner flange, the elastic connecting portion is compressed in the axial direction by the inner flange when the vibration is input in the axial direction, and the axial direction of the elastic connecting portion. The rigidity of the support spring is increased. Therefore, the tunable region of the spring ratio in the axial direction and the direction perpendicular to the axial direction can be set wider.

  According to a third aspect of the present invention, in the cylindrical vibration isolator described in the first or second aspect, the axial end surface of the elastic coupling portion is an axially inclined surface inclined toward one axial direction. It is what.

  According to the third aspect, when a static load is applied in the axial direction by mounting the cylindrical vibration isolator on the other member, both axial end surfaces of the elastic coupling portion are set according to the input direction of the static load. By setting the inclined surface in the axial direction to be inclined, the initial deformation of the elastic connecting portion by the input of the static load becomes the compression deformation. Therefore, the tensile stress acting on the elastic connecting portion is reduced, and the durability of the elastic connecting portion is improved.

  According to the present invention, the elastic coupling portion that couples the inner shaft member and the outer cylindrical member has circumferential side portions that extend from the central portion to both sides in the circumferential direction in addition to the circumferential central portion. A sufficiently large rubber volume of the elastic connecting portion is secured, and a hard spring characteristic in the axial direction is realized. In addition, both sides in the circumferential direction that secure the rubber volume are smaller in the axial direction than the central part, and are out of the circumferential direction on the line where the load in the direction perpendicular to the axis acts. It can suppress that the spring characteristic in a direction becomes hard. As a result, the spring ratio in the axial direction and the direction perpendicular to the axial direction can be more freely tuned and set, and the required spring characteristics can be effectively realized.

It is a longitudinal cross-sectional view which shows the sub-frame bush as one Embodiment of this invention, Comprising: The figure corresponded in the II cross section in FIG. The front view of the sub-frame bush shown by FIG. The rear view of the sub-frame bush shown by FIG. The perspective view which shows the state which removed the outer cylinder member in the sub-frame bush shown by FIG. The side view which shows the principal part of the main body rubber elastic body which comprises the sub-frame bush shown by FIG. The figure which shows the outer peripheral surface shape of the elastic connection part which comprises the sub-frame bush as another embodiment of this invention. The figure which shows the outer peripheral surface shape of the elastic connection part which comprises the sub-frame bush as another embodiment of this invention. The figure which shows the outer peripheral surface shape of the elastic connection part which comprises the sub-frame bush as a reference form of this invention. The figure which shows the outer peripheral surface shape of the elastic connection part which comprises the sub-frame bush as another embodiment of this invention. The figure which shows the outer peripheral surface shape of the elastic connection part which comprises the sub-frame bush as another reference form of this invention.

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

  1 to 3 show a subframe bush 10 for an automobile as an embodiment of a cylindrical vibration isolator having a structure according to the present invention. The subframe bush 10 has a structure in which an inner shaft member 12 and an outer cylinder member 14 are connected by a main rubber elastic body 16. The inner shaft member 12 is attached to a vehicle body (not shown), and the outer cylinder member 14 is attached to a subframe (not shown), so that the subframe is connected to the vehicle body in a vibration-proof manner. .

  More specifically, the inner shaft member 12 is formed of a highly rigid metal material or the like, and has a substantially cylindrical shape with a thick wall and a small diameter. The inner shaft member 12 is fixed to a vehicle body (not shown) by a fixing bolt (not shown) inserted through the center hole of the inner shaft member 12.

  The outer cylinder member 14 is formed of a highly rigid metal material or the like, like the inner shaft member 12, and has a thin cylindrical shape with a large diameter. Further, an inner flange 18 that extends toward the inner peripheral side with respect to one opening in the axial direction of the outer cylinder member 14 is integrally formed, and an outer flange 20 that extends toward the outer peripheral side with respect to the other opening is integrated. Is formed. And the outer cylinder member 14 is fixed to the sub-frame side by press-fitting the outer cylinder member 14 into the attachment hole of the sub-frame which is not illustrated.

  The inner shaft member 12 and the outer cylinder member 14 having such a structure are coaxially arranged at a predetermined distance in the radial direction, and the main rubber elastic body 16 is interposed between the inner shaft member 12 and the outer cylinder member 14. Is intervening.

  The main rubber elastic body 16 as a whole has a thick, large-diameter, generally cylindrical shape. 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 the outer cylindrical member 14. Is vulcanized and bonded to the inner peripheral surface of Thereby, the inner shaft member 12 and the outer cylinder member 14 are elastically connected by the main rubber elastic body 16. In the present embodiment, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the inner shaft member 12 and the outer cylindrical member 14.

  Further, a first buffer rubber 22 and a second buffer rubber 24 integrally formed with the main rubber elastic body 16 are vulcanized and bonded to both end surfaces in the axial direction of the outer cylinder member 14. The first buffer rubber 22 is a substantially annular rubber elastic body, and is vulcanized and bonded to the outer surface of the inner flange 18 in the axial direction. On the other hand, the second buffer rubber 24 is a rubber elastic body having a substantially annular plate shape, and is vulcanized and bonded to the outer surface of the outer flange 20 in the axial direction. In addition, a plurality of protruding portions 26 having a large protruding height outward in the axial direction are formed at a plurality of locations on the circumference of the first buffer rubber 22, and at a plurality of locations on the circumference of the second buffer rubber 24, A protrusion 28 having a large protrusion height outward in the axial direction is formed.

  By such first and second buffer rubbers 22 and 24, the inner and outer flange members 18 and 20 and the vehicle body side member abut on each other in a shock-absorbing manner to input shocking large amplitude vibrations, so that the inner shaft member The relative displacement amount in the axial direction of the outer cylinder member 12 and the outer cylinder member 14 is limited. Thereby, the 1st stopper mechanism is comprised.

  The main rubber elastic body 16 is formed with a straight hole 30 penetrating in the axial direction. The straight hole 30 is a through hole that has a substantially constant cross-sectional shape and extends linearly in the axial direction, and a pair of straight holes 30 and 30 that are opposed to each other in the radial direction are formed on both sides of the inner shaft member 12. .

  Further, a stopper protrusion 32 protrudes into the tick hole 30. The stopper protrusion 32 is a rubber elastic body having a substantially rectangular cross section and extending in the axial direction. The stopper protrusion 32 is integrally formed with the main rubber elastic body 16 and protrudes radially outward from the outer peripheral surface of the inner shaft member 12. The stopper protrusions 32 are formed as a pair that protrudes toward both sides of the inner shaft member 12 in one radial direction, and each stopper protrusion 32 protrudes into each straight hole 30. The stopper protrusion 32 is formed with an axial dimension larger than the axial dimension of the outer cylindrical member 14 and extends outward in the axial direction from the position where the inner and outer flanges 18 and 20 are formed. Is curved with a curvature substantially corresponding to the outer cylinder member 14.

  Furthermore, a contact protrusion 34 that protrudes radially inward is formed on a portion of the inner peripheral surface of the outer cylindrical member 14 that faces the stopper protrusion 32 in the radial direction. The contact protrusion 34 is a rubber elastic body having a substantially rectangular cross section, and is integrally formed with the main rubber elastic body 16 fixed to the inner peripheral surface of the outer cylinder member 14. The contact protrusion 34 has a larger dimension in the circumferential direction than the stopper protrusion 32, protrudes on both sides in the circumferential direction, and has a lower protrusion height than the stopper protrusion 32. Yes. The protruding tip surface of the contact protrusion 34 is a curved surface corresponding to the protruding tip surface of the stopper protrusion 32.

  The stopper protrusion 32 protruding from the inner shaft member 12 and the abutting protrusion 34 protruding from the outer cylinder member 14 are arranged to face each other with a predetermined distance in the radial direction. When a large amplitude vibration is input in the radial direction, the inner shaft member 12 and the outer cylindrical member 14 are abutted in a shock-absorbing manner via the stopper projecting portion 32 and the abutting projecting portion 34. A second stopper mechanism is configured to limit the relative displacement in the radial direction between the member 12 and the outer cylinder member 14 in a buffering manner.

  Further, portions of the main rubber elastic body 16 located on both sides in the circumferential direction of the straight hole 30 are formed as elastic coupling portions 36. The elastic connecting portions 36 extend in the circumferential direction by a predetermined length, and are disposed on both sides of the inner shaft member 12 in the radial direction orthogonal to the radial direction in which the pair of straight holes 30, 30 oppose each other. The inner shaft member 12 and the outer cylinder member 14 are interposed between the radial directions. Further, the inner flange 18 is fixed in an embedded state at one axial end of the elastic connecting portion 36.

  Further, as shown in FIG. 4, stepped surfaces 38 are formed on both sides in the circumferential direction of the elastic connecting portion 36, and a thick-walled portion 40 whose inner portion in the circumferential direction is larger than the stepped surface 38 in the axial direction. In addition, the outer circumferential portion of the step surface 38 is a thin portion 42 having a smaller axial dimension than the thick portion 40. In other words, in the elastic connecting portion 36, the circumferential dimension of one end in the axial direction is larger than the circumferential dimension of the other end. Thereby, the elastic connection part 36 is made into the stepped shape of the circumferential direction, and as FIG. 5 shows, the outer peripheral surface shape is made into the substantially T shape by planar view.

  As shown in FIGS. 1 and 4, one end surface in the axial direction of the elastic connecting portion 36 is a first axially inclined surface 44 that inclines toward one axial direction, and elastic connection The other end surface in the axial direction of the portion 36 is a second axially inclined surface 46 inclined toward one axial direction. Further, the second axially inclined surface 46 includes a thick part axially inclined surface 48 that is an axial end face of the thick part 40 and a thin part axially inclined face 49 that is an axial end face of the thin part 42. It is configured to include.

  The first and second axially inclined surfaces 44 and 46 are inclined toward one axial side on which the inner flange 18 is formed as going from the inner shaft member 12 side to the outer cylinder member 14 side. Furthermore, the first axially inclined surface 44 and the second axially inclined surface 46 are separated from each other in the axial direction without overlapping each other in the projection in the direction perpendicular to the axis, and are elastic when a load is applied in the direction perpendicular to the axis. The connecting portion 36 is also compressively deformed in the thin portion 42. In addition, although the thick part axial direction inclined surface 48 and the thin part axial direction inclined surface 49 may be formed with mutually different inclinations, in this embodiment, they are formed with substantially the same inclination.

  In the subframe bush 10 having the structure according to this embodiment, the elastic connecting portion 36 that connects the inner shaft member 12 and the outer cylindrical member 14 includes the thick portion 40 at the center in the circumferential direction and the thick portion 40. It is comprised by the thin part 42 which protrudes in the circumferential direction both sides. Therefore, a large rubber volume of the elastic connecting portion 36 can be secured, and the spring characteristics in the axial direction can be hardened.

  Further, the inner flange 18 is integrally formed at the axial end portion (the left end portion in FIG. 1) of the outer cylinder member 14, and the thick portion 40 and the thin portion of the elastic connecting portion 36 with respect to the inner flange 18. 42 is vulcanized and bonded. As a result, the elastic coupling portion 36 is compressed and deformed by the inner flange 18 at the time of axial vibration input, so that the spring characteristics in the axial direction of the subframe bush 10 can be set to be harder. In particular, the inner flange 18 is vulcanized and bonded to the end portion on the first axially inclined surface 44 side where the circumferential length dimension of the elastic connecting portion 36 is increased, so that the axial compression deformation is caused. It is efficiently induced over the entire elastic connecting portion 36, and the intended axial spring characteristic is more effectively realized.

  On the other hand, the thin portion 42 is formed at a position where the inner shaft member 12 deviates radially outward in the projection in the main vibration input direction (up and down in FIG. 2) perpendicular to the axis. As a result, when the vibration in the direction perpendicular to the axis is input, the thin portion 42 mainly undergoes shear deformation, so the spring of the thin portion 42 becomes smaller, and the influence of the thin portion 42 on the spring characteristics of the subframe bush 10 in the direction perpendicular to the axis. Has been reduced. Therefore, it is possible to realize a soft spring characteristic in the direction perpendicular to the axis while securing the rubber volume by the thin wall portion 42, and set the ratio of the spring in the axis direction and the spring in the direction perpendicular to the axis with a high degree of freedom in tuning. I can do it. As a result, in the sub-frame bush 10, the ratio of the axial spring to the axially perpendicular spring is set to be small, and the supporting spring rigidity in the axial direction and the vibration insulation in the axially perpendicular direction are realized. Yes.

  In addition, the thin portion 42 has a smaller axial dimension than the thick portion 40. Therefore, it is possible to prevent the spring in the direction perpendicular to the axis of the thin portion 42 from becoming softer and to harden the spring in the direction perpendicular to the axis of the subframe bush 10.

  Further, a step surface 38 is provided at the boundary between the thick portion 40 and the thin portion 42, and the axial dimension of the thin portion 42 is abruptly smaller than the axial dimension of the thick portion 40. Thereby, the spring in the direction perpendicular to the axis of the thin portion 42 is prevented from becoming large, and a soft spring characteristic in the direction perpendicular to the axis is efficiently realized.

  Further, both end surfaces in the axial direction of the elastic connecting portion 36 are constituted by first and second axially inclined surfaces 44 and 46, and a load due to the vehicle weight acts by being mounted on the vehicle, so that the inner shaft member 12 is The elastic coupling portion 36 is pre-compressed in the radial direction by relative displacement to the left side in FIG. 1 in the axial direction with respect to the outer cylinder member 14. Thereby, the tensile stress of the elastic connection part 36 is reduced and durability is improved.

  In addition, the first axially inclined surface 44 and the second axially inclined surface 46 are separated in the axial direction, and a compression component also acts on the elastic connecting portion 36 when a load is applied in a direction perpendicular to the axis. . Thereby, the spring characteristic in the direction perpendicular to the axis of the subframe bush 10 can be controlled, and the ratio of the spring in the axial direction and the spring in the direction perpendicular to the axis can be easily tuned.

  In the subframe bush 10, the ratio of the axial spring to the axially perpendicular spring is adjusted by adjusting the axial dimension and the circumferential dimension of the thick part 40 and the thin part 42 in the elastic connecting part 36. The spring characteristics in the axial direction and the spring characteristics in the direction perpendicular to the axis can be easily tuned.

  Further, the straight holes 30 are formed on both sides in the radial direction with the inner shaft member 12 interposed therebetween, and a pair of elastic connecting portions 36 are formed in the radial direction substantially orthogonal to the facing direction of the straight holes 30, 30. Is provided. By these, the spring ratio in two directions perpendicular to the axis perpendicular to each other can be adjusted, and for example, compatibility between running stability and vibration insulation performance can be advantageously achieved. In particular, the central portion in the circumferential direction of the elastic connecting portion 36 where the compression spring acts predominantly when vibration is input in the direction opposite to the elastic connecting portions 36, 36 is the thick portion 40 having a large axial dimension. Therefore, it is possible to set a large spring ratio in two directions perpendicular to the axis, and the spring characteristics in the direction perpendicular to the axis can be tuned with a higher degree of freedom.

  FIG. 6 shows an elastic connecting portion 50 that is employed in a subframe bush as another embodiment of the present invention. In the elastic connecting part 50, a step surface 51 is further formed at an intermediate part in the circumferential direction of the thin part 52. As a result, the thin portion 52 is made thinner than the thick portion 40, and the first thin portion 54 is thinner than the first thin portion 54, and protrudes outward in the circumferential direction from the first thin portion 54. It is set as the stepped shape of the circumferential direction which has the 2nd thin part 56 to do.

  According to the elastic connecting part 50 having such a structure, by adjusting the axial dimension and the circumferential dimension of the first and second thin-walled parts 54 and 56 having different axial dimensions from each other, the axially perpendicular direction can be adjusted. The spring characteristics can be adjusted more accurately and easily.

  Further, FIG. 7 shows an elastic connecting portion 60 employed in a subframe bush as another embodiment of the present invention. In the elastic connection part 60, a thin part 42 is formed so as to protrude outward in the circumferential direction from the axially intermediate part of the thick part 40. Thus, the thin part 42 does not necessarily have to be provided at the axial end of the thick part 40.

FIG. 8 shows an elastic connecting portion 70 of the subframe bush as a reference form of the present invention. The elastic connection part 70 is comprised by the thick part 40 and the thin part 72, and the thin part 72 has the taper shape of the circumferential direction in which an axial direction dimension becomes small gradually toward the circumferential direction outer side. In addition, the axial direction end surface of the thick part 40 and the thin part 72 is smoothly connected, without having a level | step difference or a local unevenness | corrugation.

  In the sub-frame bush having such an elastic connecting portion 70, the spring ratio in the axial direction and the direction perpendicular to the axial direction can be adjusted in the same manner as the sub-frame bush 10 of the above-described embodiment, and the vibration proof characteristic can be tuned. The degree of freedom can be increased. Moreover, since the thick portion 40 and the thin portion 72 are smoothly connected without having a step or unevenness, it is possible to prevent stress concentration and improve durability.

  It is also possible to employ a structure in which the stepped shape of the elastic connecting portion 36 and the tapered shape of the elastic connecting portion 70 are combined, such as the elastic connecting portion 80 shown in FIG. That is, in the elastic connection part 80, the thin part 81 is comprised by the 1st-3rd thin part 82,86,88. More specifically, a stepped surface in which a tapered first thin portion 82 is integrally formed on the outer peripheral side of the thick portion 40 and the end surface on the outer peripheral side of the first thin portion 82 extends in the axial direction. 84. Further, a second thin portion 86 having a substantially constant axial dimension smaller than that of the first thin portion 82 is integrally formed on the outer side in the circumferential direction of the first thin portion 82 with the stepped surface 84 interposed therebetween. . Furthermore, on the outer side in the circumferential direction of the second thin portion 86, a tapered third thin portion 88 whose axial dimension decreases toward the outer side in the circumferential direction is integrally formed.

  According to the sub-frame bush provided with the elastic connecting portion 80 having such a structure, it is possible to perform more detailed tuning by adjusting the shapes and dimensions of the first to third thin-walled portions 82, 86, and 88, respectively. Become.

  Further, in the elastic connecting portion provided with the tapered thin wall portions on both sides in the circumferential direction, like the elastic connecting portion 90 shown in FIG. 10, the axial end surface of the thin wall portion 92 has a concave curved taper shape. You may do it. According to this, as compared with the case of adopting a linear taper shape, the axial dimension of the circumferentially central end of the thin portion 92 can be drastically reduced, and a low dynamic spring can be achieved in the direction perpendicular to the axis. In addition, the stress can be distributed as in the case of the linear taper shape.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, both end portions in the circumferential direction of the elastic connecting portion whose axial dimension is reduced may not be formed with a substantially constant axial dimension, and the axial dimension is not gradually decreased toward the outer side in the circumferential direction. May be. Specifically, an inversely tapered shape in which the axial dimension gradually increases toward the outer side in the circumferential direction may be used. Even in these shapes, it is possible to set the axial spring larger or smaller than the spring perpendicular to the axis while maintaining the spring perpendicular to the axis. Therefore, both the spring characteristics in the axial direction and the spring characteristics in the direction perpendicular to the axis can be set with a high degree of freedom, and the spring ratio in the axial direction and the direction perpendicular to the axis can be freely tuned and set. Become.

  Further, the present invention is not only applied to a tubular vibration isolator for automobiles, but can also be suitably applied to railway trains, industrial vehicles, and the like. Furthermore, the scope of application of the present invention is not limited to the rubber bush, but may be applied to, for example, a rubber mount.

10: Subframe bush (cylindrical vibration isolator), 12: Inner shaft member, 14: Outer cylinder member, 16: Rubber elastic body of main body, 18: Inner flange, 30: Straight hole, 36, 50, 60, 70, 80, 90: elastic connecting part, 40: thick part (circumferential center), 42, 52, 72, 82, 92: thin part (both sides in the circumferential direction), 44: first axially inclined surface (axially inclined) Surface), 46: second axially inclined surface (axially inclined surface)

Claims (3)

In the cylindrical vibration isolator in which the outer cylindrical member is arranged separately on the outer peripheral side of the inner shaft member, and the inner shaft member and the outer cylindrical member are connected by the main rubber elastic body,
A pair of straight holes penetrating the main rubber elastic body in the axial direction are formed on both sides in a direction perpendicular to the axis across the inner shaft member, and the main rubber elastic body is divided in the circumferential direction by the pair of straight holes. A pair of elastic connecting portions, the axial dimensions on both sides in the circumferential direction of each elastic connecting portion are smaller than the center in the circumferential direction , and
The cylindrical vibration isolator characterized in that the pair of elastic connecting portions have a stepped shape in the circumferential direction having a stepped surface on both sides in the circumferential direction and having a reduced axial dimension .   2. The cylindrical shape according to claim 1, wherein an inner flange is formed at one axial end of the outer cylindrical member, and the pair of elastic coupling portions of the main rubber elastic body are fixed to the inner flange. Anti-vibration device.   The cylindrical vibration isolator according to claim 1 or 2, wherein an axial end surface of the elastic connecting portion is an axially inclined surface inclined toward one axial direction.

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