JP4716387B2 - Anti-vibration bush - Google Patents

Description

  The present invention relates to an anti-vibration bush used by being incorporated in an automobile suspension device or the like.

  2. Description of the Related Art Conventionally, in an automobile suspension device, a vibration isolating bush is used at a connection portion between a vehicle body and a suspension for the purpose of vibration damping and buffering. Such an anti-vibration bush is generally provided between a shaft member such as an inner cylinder, an outer cylinder arranged on the outer side of the shaft member, and between the shaft member and the outer cylinder so as to elastically support both. And an anti-vibration substrate made of a rubber-like elastic body.

  By the way, in the anti-vibration bush used in this type of suspension device, the spring constant in the direction perpendicular to the axis and in the axial direction is increased while the spring constant in the torsional direction and the twisting direction is increased in order to improve riding comfort and steering stability. It is required to reduce the constant.

  In order to reduce the spring constant in the twisting direction while increasing the spring constant in the direction perpendicular to the axis in response to such a requirement, a bulging portion that bulges in the axis perpendicular direction is provided at the axial center of the inner cylinder. So-called bulge type vibration-proof bushings have been developed (see Patent Documents 1 and 2 below).

Further, in Patent Document 3 below, for the purpose of further improving the bulge type vibration-proof bushing, an outer cylinder is provided with a bulging portion whose outer peripheral surface forms a convex spherical surface at the axially central portion of the inner cylinder. Are formed in a straight cylindrical shape having a constant outer peripheral diameter in the axial direction, and the inner peripheral surface portion of the central portion in the axial direction surrounding the convex spherical surface is recessed in a concave spherical surface concentric with the convex spherical surface. Has been proposed. According to this configuration, since the outer peripheral surface of the outer cylinder is formed into a straight cylinder while sufficiently reducing the spring constant in the twisting direction, a sufficient axial dimension for press-fitting with the cylindrical holder of the link is provided. It can be ensured and the removal force from the cylindrical holder can be improved.
Japanese Patent Laid-Open No. 09-1000085 Japanese Patent Laid-Open No. 09-100811 JP 2008-89127 A

  In the configuration described in Patent Document 3, in order to provide a concave spherical surface on the inner peripheral surface while making the outer peripheral surface of the outer cylinder a straight cylinder, it is necessary to produce the outer cylinder by cutting, resulting in a high cost. There is.

  Note that the above Patent Document 2 assumes that the intermediate cylinder (interring) is provided between the inner cylinder and the outer cylinder, and instead of providing the outer cylinder, the anti-vibration base is provided on the outer circumference of the intermediate cylinder. It is disclosed that a pair of flanges are formed with a predetermined width and projecting in the radial direction on both right and left side edges, and the cylindrical holder is press-fitted and fixed to the outer periphery of the vibration-proof base between the pair of flanges. (Figure 3). However, this document is intended to increase the rigidity in the direction perpendicular to the axis by providing an intermediate cylinder, and the rubber-like elastic body on the outer peripheral side of the intermediate cylinder functions as a vibration-proof base. There is no suggestion of the present invention.

  The present invention provides an anti-vibration bushing capable of reducing the cost while maintaining a small spring constant in the twisting direction and a high spring constant in the direction perpendicular to the axis, and without impairing the press-fit holding property of the link to the cylindrical holder. The purpose is to provide.

An anti-vibration bush according to the present invention includes a shaft member, an outer cylinder that concentrically surrounds the shaft member, and a vibration-proof base made of a rubber-like elastic body interposed between the shaft member and the outer cylinder. An axial center portion of the shaft member is formed in a first bulging portion that bulges outward in a direction perpendicular to the axis, and surrounds the first bulging portion. Is formed in the second bulging portion that bulges outward in the direction perpendicular to the axis, and the inner peripheral surface of the second bulging portion is formed in a concave portion corresponding to the outer peripheral surface of the first bulging portion. It has been done. The anti-vibration base is bonded to the outer peripheral surface of the shaft member including the first bulging portion and the inner peripheral surface of the outer cylinder including the concave surface portion to connect the shaft member and the outer tube. Is provided. The outer peripheral surface of the outer cylinder is covered with a press-fit elastic portion made of a rubber-like elastic body that is press-fitted and fixed in a cylindrical holder, and the press-fit elastic portion has an outer peripheral surface having a cylindrical surface shape. The both axial end portions are formed to be thicker than the axial central portion covering the second bulging portion, and the axial central portion is formed to be gradually thinner toward the inner side in the axial direction . A convex portion that is formed in a thin film shape at an axial position corresponding to the apex of the bulging portion and is compressed by the cylindrical holder on the outer peripheral surface of the press-fit elastic portion having a cylindrical surface shape is formed on the second bulging portion. Provided on both sides in the axial direction excluding the axial position corresponding to the apex, and through portions for connecting the vibration-proof base and the press-fit elastic portion to the axial end of the outer cylinder are provided at a plurality of locations in the circumferential direction. , provided axially inward the projections than the through part so as not to said penetrating portion That.

  In the anti-vibration bush having such a configuration, the first bulging portion is provided at the axial center portion of the shaft member, and the concave portion is provided on the inner peripheral surface of the outer cylinder surrounding the first bulging portion. Since the anti-vibration base is interposed between them, the spring constant in the direction perpendicular to the axis can be increased while the spring constant in the twisting direction can be reduced. In addition, the concave surface portion of the inner peripheral surface of the outer cylinder is formed by bulging the axial center portion of the outer cylinder outward. With such a structure, a cylindrical body having a constant thickness is bent. Since it is obtained by doing, cost can be reduced compared with the case where it cuts. On the other hand, when the outer cylinder has the second bulging portion that bulges outward in the direction perpendicular to the axis, it is difficult to press-fit in the cylindrical holder as it is, but the outer cylinder has a cylindrical surface on the outer circumferential surface. By covering the press-fit elastic part having the outer peripheral surface and providing a convex part on the outer peripheral surface of the press-fit elastic part, when the press-fitted into the cylindrical holder, the convex part is compressed. The pulling force (force required for pulling out) can be increased, and the press-fitting retention can be improved.

  In the vibration-proof bushing, the convex portion may be an annular convex portion that extends along the circumferential direction on the outer peripheral surface of the press-fit elastic portion. One or a plurality of such annular convex portions can be provided on both sides in the axial direction of the press-fit elastic portion.

  For example, the annular convex portion includes a first convex portion provided on an outer peripheral surface at the axial end portion of the press-fit elastic portion, and a second convex portion provided on an outer peripheral surface at the axial center portion of the press-fit elastic portion. It can comprise with a convex part. By providing a plurality of annular projections in the axial direction in this way, the overall removal force can be secured while suppressing the compression rate of each of the annular projections, so that compression is performed after press-fitting into the cylindrical holder. The problem of returning to the pulling-out direction due to the reaction force of the rubber-like elastic body made can be solved. Further, by providing an annular convex portion (second convex portion) at the thin axial center portion covering the second bulging portion, it is possible to increase the removal force.

  In this case, the protrusion height of the first protrusion may be set larger than the protrusion height of the second protrusion. Since the press-fit elastic part is thicker at the axial end than the central part in the axial direction, by increasing the first convex part provided at the axial end, the compression rate can be increased and the removal force can be increased. it can.

  Further, in the above case, an annular straight portion that is recessed inward in the axial direction is provided on the axial end surface of the vibration isolating base, and the axial center of the first convex portion is more axial than the bottom of the straight portion. You may set to the direction outward side. Such a configuration is effective when the straight part is deep, and the spring constant in the twisting direction can be reduced by the deep straight part. Alternatively, the axial center of the first convex portion may be set on the inner side in the axial direction from the bottom of the straight portion.

  In the vibration isolating bush, the convex portion may be an axial convex portion extending along the axial direction on the outer peripheral surface of the press-fit elastic portion, and a plurality of the axial convex portions may be provided in the circumferential direction. With such an axial convex portion, it is possible to improve the press-fitting workability into the cylindrical holder.

  In this case, the axial convex portion may be provided from the thick axial end portion of the press-fit elastic portion to the thin axial central portion, thereby increasing the removal force from the cylindrical holder. Can do.

In the anti-vibration bush according to the present invention , as described above, a penetrating portion that connects the anti-vibration base and the press-fit elastic portion is provided at the axial end portion of the outer cylinder, and the convex portion does not reach the penetrating portion. In this way, it is provided on the inner side in the axial direction than the penetrating portion. By providing such a penetrating part, the press-fit elastic part can be easily injection-molded simultaneously with the vibration-proof base. On the other hand, if the convex portion is provided so as to cover the penetrating portion, the rubber-like elastic body escapes to the inner vibration-proof substrate side through the penetrating portion when pressed into the cylindrical holder, and is compressed. Although it is difficult to increase the rate, by providing the convex portion on the inner side in the axial direction from the penetrating portion, it is possible to eliminate such inconvenience and to secure the removal force due to the compression of the convex portion.

  The vibration-proof bushing of the present invention can reduce the cost while maintaining the small spring constant in the twisting direction and the high spring constant in the direction perpendicular to the axis, and without impairing the press-fitting retention of the link to the cylindrical holder. Can do.

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

  FIG. 1 shows an anti-vibration bush 10 according to a first embodiment of the present invention. The anti-vibration bush 10 connects various link members such as a lower link and a toe control link to a suspension member in a multi-link suspension device.

  The vibration isolating bush 10 includes an inner cylinder 12 as a shaft member, an outer cylinder 14 that surrounds the inner cylinder 12 in an axially parallel and coaxial manner, and a rubber vibration isolator that is interposed between the inner cylinder 12 and the outer cylinder 14. And a base 16. As shown in FIG. 3, the inner cylinder 12 is clamped with a fastening member (not shown) such as a bolt in a state in which both end surfaces are sandwiched between brackets 1 of suspension members which are one connection part. Further, the outer cylinder 14 is fixed by being press-fitted into the cylindrical holder 3 of the link member 2 which is the other connecting portion, whereby the anti-vibration bush 10 is attached to the bracket of the link member 2 and the suspension member. 1 is connected in a vibration-proof manner.

  The inner cylinder 12 is a metal cylindrical member, and includes a first bulging portion 18 that bulges in a curved shape over the entire circumference toward the outer side Yo in the direction perpendicular to the axis at the central portion in the axial direction X. In this example, the first bulging portion 18 has a spherical belt shape, and thus the convex surface portion 18A constituting the outer peripheral surface of the first bulging portion 18 is formed in a spherical convex surface. Specifically, the convex surface portion 18A has a spherical belt shape that forms the axial central portion of a spherical surface having a center P on the axis L of the inner cylinder 12, and the general cylindrical portion (outer side) at both axial ends of the inner cylinder 12 is formed. It is formed smoothly and continuously from the outer peripheral surface 12A of a straight cylindrical portion having a constant diameter.

  The outer cylinder 14 is a metallic cylindrical member, and a central portion in the axial direction X surrounding the first bulging portion 18 bulges in a curved shape over the entire circumference toward the outer side perpendicular to the axial direction Yo. 2 The bulge 20 is bent. That is, the outer cylinder 14 is formed of a cylindrical body having a constant plate thickness, and the second bulging portion 20 is provided by the outer side of the central portion being curved in the axial direction. The peripheral surface is formed in the concave surface portion 20 </ b> A corresponding to the outer peripheral surface of the first bulging portion 18.

  In this example, the second bulging portion 20 has a spherical shape, and therefore the concave surface portion 20 </ b> A constituting the inner peripheral surface of the second bulging portion 20 is concentric with the convex surface portion 18 </ b> A of the first bulging portion 18. It is formed in a spherical concave surface having a shape (that is, having a common center P). Further, the convex surface portion 20 </ b> B constituting the outer peripheral surface of the second bulging portion 20 is formed in a spherical convex surface concentric with the convex surface portion 18 </ b> A of the first bulging portion 18. The concave surface portion 20A and the convex surface portion 20B are not strict ball bands in the state before the drawing of the outer cylinder 14, but are positions where the center P is shifted in the axis-perpendicular direction Y from the axis L of the outer cylinder 14. Then, after the vulcanization molding of the vibration-proof base 16, the center P is formed in the shape of a spherical band located on the axis L as shown in FIG.

  The concave surface portion 20A of the second bulging portion 20 is formed smoothly and continuously from the inner peripheral surface 14A of the general cylindrical portion (straight cylindrical portion having a constant inner and outer diameter) at both axial ends of the outer tube 14. Further, the convex surface portion 20B of the second bulging portion 20 is formed so as to be smoothly continuous from the outer peripheral surface 14B of the general cylindrical portion of the outer cylinder 14.

  The anti-vibration base 16 is vulcanized and bonded to the outer peripheral surface 12A of the inner cylinder 12 including the convex surface portion 18A and the inner peripheral surface 14A of the outer cylinder 14 including the concave surface portion 20A. Is a cylindrical rubber member that connects the two.

  On both end surfaces in the axial direction of the vibration isolator base 16, annular straight portions 22 that are recessed in a curved cross section toward the axially inward Xi side are respectively provided over the entire circumference. As shown in FIG. 2, on the axially outward Xo side of the phantom spherical surface 24 defined by the concave surface portion 20 </ b> A on the outer cylinder 14 side, the antivibration base 16 is not filled between the inner cylinder 12 and the outer cylinder 14. The depth of the straight portion 22 is set. Accordingly, the bottom 22 </ b> A of the straight portion 22 (that is, the portion located in the innermost Xi in the axial direction X in the straight portion 22) 22 </ b> A is set to enter the inside of the phantom spherical surface 24.

  In this example, the inner peripheral surface 14A of the outer cylinder 14 is vulcanized and bonded to the vibration isolating base 16 over the entire axial direction X. From both ends of the inner peripheral surface 14A in the axial direction, the vibration isolating base 16 is attached. A continuous rubber layer 16A is provided. In addition, a rubber layer 16 </ b> B continuous from the vibration isolating base 16 is also vulcanized and molded on the outer peripheral surface 12 </ b> A of the inner cylinder 12 facing this.

  On the outer peripheral surface 14B of the outer cylinder 14, a press-fit elastic part 26 made of a rubber-like elastic body for press-fitting and fixing in the cylindrical cylindrical holder 3 is covered. The press-fit elastic portion 26 is a cylindrical rubber member that covers the outer peripheral surface 14B of the outer cylinder 14 over the entire axial direction X and the entire periphery, and is provided by being vulcanized and bonded to the outer peripheral surface 14B.

  The press-fit elastic part 26 is formed of the same rubber material as that of the vibration-isolating base 16, and the press-fit elastic part 26 and the anti-vibration base 16 are connected to each other through a through-hole 28 provided at the axial end of the outer cylinder 14. Are connected to each other. The through portion 28 is formed by cutting out the axial end of the outer cylinder 14 at a plurality of locations in the circumferential direction. Although not shown, in this example, the through portion 28 is equally spaced at four locations on the circumference. Are distributed.

  The press-fit elastic portion 26 corresponds to the inner peripheral surface of the cylindrical holder 3 having a constant inner diameter in the axial direction X, and the outer peripheral surface 26A has a cylindrical surface shape, that is, the outer peripheral surface 26A has a diameter in the axial direction X. Is set to be almost constant. On the other hand, the outer peripheral surface 14B of the outer cylinder 14 to which the press-fit elastic portion 26 is vulcanized and bonded has the convex surface portion 20B of the second bulging portion 20 at the axial center portion as described above. For this reason, the press-fit elastic portion 26 has both axial end portions 26B and 26B formed thicker than the axial central portion 26C covering the second bulging portion 20, and the axial central portion 26C has a spherical shape. The convex surface portion 20B is formed so as to be gradually thinner toward the axially inward Xi side. The press-fit elastic portion 26 is formed in a thin film shape at the axial center position 26D corresponding to the apex of the convex surface portion 20B that is the thinnest. By forming the thin film in this way, the press-fit elastic portion 26 does not contribute to the spring constant in the direction perpendicular to the axis Y, and the spring constant in the direction perpendicular to the axis Y is determined only by the inner vibration-proof base 16. It is possible to eliminate the decrease in the spring constant in the direction perpendicular to the axis Y due to the provision of the press-fit elastic part 26 on the outer side, and to keep the spring constant high.

  The cylindrical outer peripheral surface 26 </ b> A of the press-fit elastic portion 26 formed as described above is provided with a convex portion 30 that is compressed by the inner peripheral surface of the cylindrical holder 3. The convex portion 30 is an annular convex portion extending over the entire circumference along the circumferential direction on the outer peripheral surface 26A of the press-fit elastic portion 26, and as shown in an enlarged view in FIG. 2, from the outer peripheral surface 26A of the press-fit elastic portion 26. It is raised in a curved shape, and the cross-sectional shape is formed into a gentle mountain shape.

  Two annular convex portions 30 are provided on each of the left and right sides of the axial center position 26D of the press-fit elastic portion 26. As shown in FIG. 2, the two annular convex portions 30 include a first convex portion 30A provided on the outer peripheral surface of the thick axial end portion 26B and a thin central axial portion 26C. The second convex portion 30B provided on the outer peripheral surface of the second convex portion 30B. The protrusion height and the cross-sectional shape of the first protrusion 30A and the second protrusion 30B are set to be the same in this example.

  The first convex portion 30A has an axial center (a center line that bisects the first convex portion in the axial direction X) N set to the axially outward Xo side from the bottom 22A of the straight portion 22. Yes. Thus, the spring constant in the twisting direction Z (see FIG. 3) can be reduced by setting the straight portion 22 deeper than the position where the first convex portion 30A is provided.

  Further, as shown in FIG. 2, the first convex portion 30 </ b> A does not reach the penetrating portion 28 that connects the press-fit elastic portion 26 and the vibration isolation base 16, that is, the first convex portion 30 </ b> A penetrates in the direction perpendicular to the axis Y. It is provided on the axially inward Xi side with respect to the through portion 28 so that the portion 28 does not overlap.

  The second convex portion 30B is provided closer to the axial end portion in the axial central portion 26C that gradually becomes thinner toward the axially inward Xi side.

  As shown in FIG. 2, the outer peripheral surface 26 </ b> A of the press-fit elastic portion 26 is provided with a tapered portion 32 having a tapered surface shape with a gradually decreasing diameter toward the tip end at the axial end edge. Workability is improved.

  When manufacturing the anti-vibration bushing 10, the inner cylinder 12 having the first bulging portion 18 and the outer cylinder 14 having the second bulging portion 20 are arranged in a molding die (not shown), and the molding die By injecting the rubber material into the inside, the anti-vibration base 16 between the inner cylinder 12 and the outer cylinder 14 and the press-fit elastic part 26 on the outer periphery of the outer cylinder 14 are vulcanized. At this time, since the cavity for molding the vibration isolating base 16 and the cavity for molding the press-fit elastic part 26 are communicated with each other by the through portion 28 provided in the outer cylinder 14, the moldability can be improved. The vulcanized molded body thus obtained is then subjected to a drawing process on the outer cylinder 14 to reduce the diameter of the outer cylinder 14, whereby the vibration isolating bush 10 shown in FIG. 1 is obtained.

  The obtained anti-vibration bush 10 is assembled to the vehicle as shown in FIG. 3 as described above. At that time, the outer cylinder 14 is press-fitted and fixed in the cylindrical holder 3 via the press-fit elastic part 26. The outer peripheral surface 26 </ b> A of the press-fit elastic portion 26 is set to have a slightly larger diameter than the inner peripheral surface of the cylindrical holder 3. By press-fitting the press-fit elastic portion 26 into the cylindrical holder 3, The provided annular convex portion 30 is compressed by the inner peripheral surface of the cylindrical holder 3 and is completely buried in the press-fit elastic portion 26 body. Therefore, the entire outer peripheral surface 26A of the press-fit elastic portion 26 is in close contact with the inner peripheral surface of the cylindrical holder 3 with the rubber compression rate of the press-fit elastic portion 26 locally increased at the position of the annular convex portion 30. It is press-fitted and fixed.

  The vibration isolating bush 10 is provided with a first bulging portion 18 on the inner cylinder 12 and a concave surface portion 20A on the inner peripheral surface 14A of the outer cylinder 14 surrounding the first bulging portion 18. Since the anti-vibration base 16 is interposed therebetween, the spring constant in the twisting direction Z can be reduced while increasing the spring constant in the direction perpendicular to the axis Y. In particular, the concave surface portion 20A of the outer cylinder 14 is a concave spherical surface that is concentric with the convex surface portion 18A of the inner cylinder 12, so that it is interposed between the concave surface portion 20A and the convex surface portion 18A when displaced in the twisting direction Z. Further, since the force received by the anti-vibration base 16 is only shear deformation, the spring constant in the twisting direction Z can be effectively reduced. Further, at the time of displacement in the direction perpendicular to the axis Y, the escape of rubber in the axial direction X is restricted by the concave surface portion 20A on the outer cylinder 14 side, and the spring constant in the direction perpendicular to the axis Y can be increased.

  Further, since the thickness in the axial direction X of the vibration isolating base 16 interposed between the concave surface portion 20A and the convex surface portion 18A is constant, non-uniform stress is generated particularly when the displacement is performed in the direction perpendicular to the axis Y. By suppressing the action, it is possible to improve the vibration isolation performance and durability.

  Moreover, according to this embodiment, since the outer cylinder 14 consists of a cylindrical body with a constant plate | board thickness, compared with the said conventional thing which forms an outer cylinder by cutting, cost can be reduced. On the other hand, when the outer cylinder 14 has the second bulging portion 20 as it is, it is difficult to press-fit in the cylindrical holder 3 as it is, but a press-fit elastic portion 26 is provided on the outer peripheral side of the outer cylinder 14. By providing the annular convex portion 30 on the outer peripheral surface 26A, when the annular convex portion 30 is press-fitted into the cylindrical holder 3, the annular convex portion 30 is compressed, so that the pulling force can be increased, and the press-fitting and holding is performed satisfactorily. Can be made.

  Since the press-fit elastic portion 26 is formed in a thin film shape at the axial center position 26D, the spring constant in the direction perpendicular to the axis Y does not decrease, while in the twisting direction Z, the axial end portion 26B is thick. Since it is meat-like and a thick rubber part is interposed between the outer cylinder 14 and the cylindrical holder 3, the displacement can be made softer than when this part is a rigid body.

  Further, as the annular convex portion 30, not only the first convex portion 30A provided at the thick axial end portion 26B of the press-fit elastic portion 26 but also the second convex portion 30B is provided at the thin axial central portion 26C. Therefore, it is possible to increase the compression rate and the removal force.

  Further, since the first convex portion 30A is provided on the axially inward Xi side so as not to reach the penetrating portion 28 of the outer cylinder 14, a rubber portion due to compression of the first convex portion 30A at the time of press-fitting into the cylindrical holder 3 However, it is possible to suppress escape through the through portion 28 to the inner vibration-proof base 16 side, and therefore, it is possible to effectively ensure the removal force due to the compression of the first convex portion 30A.

  FIG. 4 shows an anti-vibration bush according to the second embodiment. This example is different from the first embodiment in that the protrusion height of the first protrusion 30A is set larger than the protrusion height of the second protrusion 30B.

  That is, in this example, the height H1 of the first convex portion 30A provided at the thick axial end portion 26B of the press-fit elastic portion 26 is the height H2 of the second convex portion 30B provided at the thin axial central portion 26C. Is set larger.

  If the heights of both are the same (H1 = H2), the compression rate of the rubber is lower in the thick axial end portion 26B than in the thinner axial central portion 26C. By setting the first convex portion 30A provided at the thick axial end portion 26B to be high, the compression rate at the axial end portion 26B is made equal to or higher than the axial central portion 26C, and the removal force is increased. Can do. Other configurations and operational effects are the same as those of the first embodiment.

  FIG. 5 shows an anti-vibration bush according to the third embodiment. In this example, the first embodiment is different from the first embodiment in that the first protrusion 30A is provided so that the axial center N of the first protrusion 30A is closer to the axially inward Xi side than the bottom 22A of the straight portion 22. Is different.

  That is, in this example, the first convex portion 30A is provided closer to the axially inner Xi side than the first embodiment, and is provided closer to the axially inner end of the axial end portion 26B of the press-fit elastic portion 26. ing. In accordance with this, the second convex portion 30B is also provided on the axially inward Xi side from the first embodiment.

  Thus, by providing the first convex portion 30A closer to the axially inward Xi side, when compressed by the inner peripheral surface of the cylindrical holder 3, the compressed rubber portion is axially outward. Escape to the open side of Xo can be prevented, which is effective for improving the removal force. Other configurations and operational effects are the same as those of the first embodiment.

  FIG. 6 shows an anti-vibration bush according to the fourth embodiment. This example is different from the first embodiment in that only one annular convex portion 30 is provided at each of the axial end portions 26B and 26B of the press-fit elastic portion 26.

  That is, in this example, only one annular convex portion 30 is provided at the axial end portion 26B of the press-fit elastic portion 26, and no annular convex portion is provided at the axial central portion 26C. The annular convex portion 30 is provided on the axially inward Xi side of the through portion 28 so as not to reach the through portion 28 of the outer cylinder 14.

  Thus, you may comprise the cyclic | annular convex part 30 by only one of the axial direction edge parts 26B. However, with only one, the vibration-proof bushing becomes more cylindrical due to the reaction force of the compressed rubber as the projecting height of the annular convex portion 30 is set higher in order to increase the removal force from the cylindrical holder 3. On the other hand, the force that tries to come out of the cylindrical holder 3 is increased. Therefore, it is preferable to provide a plurality of annular protrusions 30 in the axial direction X (that is, the first protrusion 30A and the second protrusion 30B) as in the first to third embodiments. While suppressing the compression rate of the two annular protrusions 30A and 30B, the overall compression rate can be increased to ensure the removal force. Other configurations and operational effects are the same as those of the first embodiment.

  7 and 8 show an anti-vibration bush according to the fifth embodiment. In this example, as a convex portion provided on the cylindrical outer peripheral surface 26 </ b> A of the press-fit elastic portion 26, a first embodiment is provided in that an axial convex portion 34 extending in the axial direction X is provided instead of the annular convex portion 30. Different from form.

  That is, in this example, a plurality of axial projections 34 extending in the axial direction X are provided in the circumferential direction C on the outer circumferential surface 26 </ b> A of the press-fit elastic portion 26. The axial convex portions 34 are provided at equal intervals in the circumferential direction C of the press-fit elastic portion 26. In this example, a total of twelve axial convex portions 34 are formed at intervals of 30 degrees.

  As shown in FIG. 8, the axial convex portion 34 protrudes from the outer peripheral surface 26 </ b> A of the press-fit elastic portion 26 in a curved shape, and is formed in a mountain shape with a gentle cross-sectional shape. As shown in FIG. 7, the axial convex portion 34 is provided in the axial direction X from the thick axial end portion 26B of the press-fit elastic portion 26 to the thin axial central portion 26C. The direction inner end 34 </ b> A and the axial direction outer end 34 </ b> B are formed in an inclined surface shape that is inclined so as to gradually become lower toward the tip. Further, the axially outer end 34 </ b> B terminates closer to the axially inner Xi side than the penetrating portion 28 so as not to reach the penetrating portion 28 of the outer cylinder 14.

  Thus, by making the axial convex portion 34 extending in the same axial direction X as the press-fitting direction into the cylindrical holder 3, the press-fitting workability into the cylindrical holder 3 can be improved. Moreover, since both ends 34A and 34B of the axial direction convex part 34 are inclined surface shape, press-fit workability | operativity can further be improved.

  Further, by extending the axial convex portion 34 not only from the thick axial end portion 26B but also from there to the thin axial central portion 26C, the removal force from the cylindrical holder 3 is effectively reduced. Can be increased. Other configurations and operational effects are the same as those of the first embodiment.

  In the above embodiment, the annular convex portion 30 and the axial convex portion 34 are provided as convex portions formed on the outer peripheral surface 26A of the press-fit elastic portion 26, but the shape of the convex portion is not limited to these. Various modifications are possible. Moreover, in the said embodiment, in order to set it as a bulge type bush, although the 1st bulging part 18 of the inner cylinder 12 was integrally formed with the metal material, the resin-made cyclic | annular covering body is provided in the outer peripheral surface of an inner cylinder. For example, the bulging portion may be formed. Although not enumerated one by one, various modifications can be made without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for various vibration isolating bushes such as a vibration isolating bush used by being incorporated in an automobile suspension device and a cylindrical vibration isolating bush as an engine mount.

Sectional view of the vibration-proof bushing according to the first embodiment An enlarged sectional view of the main part of the anti-vibration bush Sectional view showing the assembled state of the anti-vibration bush The principal part enlarged view of the vibration proof bush concerning 2nd Embodiment The principal part enlarged view of the anti-vibration bush concerning 3rd Embodiment The principal part enlarged view of the anti-vibration bush concerning 4th Embodiment The principal part enlarged view of the vibration-proof bushing which concerns on 5th Embodiment Side view of vibration-proof bushing according to fifth embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Anti-vibration bush 12 ... Inner cylinder (shaft member), 12A ... Outer peripheral surface 14 ... Outer cylinder, 14A ... Inner peripheral surface, 14B ... Outer peripheral surface 16 ... Anti-vibration base | substrate 18 ... First bulging part, 18A ... Convex surface part DESCRIPTION OF SYMBOLS 20 ... 2nd bulging part, 20A ... Concave part 22 ... Straight part, 22A ... Bottom 26 ... Press-fit elastic part, 26A ... Outer peripheral surface, 26B ... Axial end part, 26C ... Axial center part, 26D ... Axial center Position 28 ... penetrating part 30 ... annular convex part (convex part), 30A ... first convex part, 30B ... second convex part 34 ... axial convex part (convex part)
C: circumferential direction X: axial direction, Xi: axially inward, Xo: axially outward Y: axially perpendicular direction, Yo: axially orthogonally outwardly

Claims (8)

In an anti-vibration bush comprising: a shaft member; an outer cylinder that concentrically surrounds the shaft member; and a vibration-proof base made of a rubber-like elastic body interposed between the shaft member and the outer cylinder.
An axial central portion of the shaft member is formed in a first bulging portion that bulges outward in a direction perpendicular to the axis, and an axial central portion of the outer cylinder surrounding the first bulging portion is a shaft. Formed in a second bulging portion bulging outward in a right angle direction, the inner peripheral surface of the second bulging portion is formed in a concave surface portion corresponding to the outer peripheral surface of the first bulging portion,
The anti-vibration base is bonded to the outer peripheral surface of the shaft member including the first bulging portion and the inner peripheral surface of the outer cylinder including the concave surface portion to connect the shaft member and the outer tube. Provided,
The outer peripheral surface of the outer cylinder is covered with a press-fit elastic portion made of a rubber-like elastic body that is press-fitted and fixed in a cylindrical holder, and the press-fit elastic portion has an outer peripheral surface having a cylindrical surface shape. Both end portions are formed thicker than the axially central portion covering the second bulging portion, and the second bulging portion is formed so as to be gradually thinner toward the inner side in the axial direction at the axially central portion. A convex portion that is formed in a thin film shape at an axial position corresponding to the apex of the cylinder and is compressed by the cylindrical holder on the outer peripheral surface of the press-fit elastic portion that forms a cylindrical surface corresponds to the apex of the second bulge provided on both sides of the axial direction excluding the axial position,
A plurality of penetrating portions for connecting the vibration-proof base and the press-fit elastic portion to the axial end portion of the outer cylinder are provided at a plurality of locations in the circumferential direction, so that the convex portion does not reach the penetrating portion. An anti-vibration bush provided on the inner side in the direction .   The vibration-proof bushing according to claim 1, wherein the convex portion is an annular convex portion extending along a circumferential direction on an outer peripheral surface of the press-fit elastic portion.   The annular convex portion is a first convex portion provided on the outer peripheral surface at the axial end portion of the press-fit elastic portion, and a second convex portion provided on the outer peripheral surface at the axial center portion of the press-fit elastic portion. The vibration-insulating bush according to claim 2, comprising:   The anti-vibration bush according to claim 3, wherein the protruding height of the first convex portion is set larger than the protruding height of the second convex portion.   An annular straight portion that is recessed toward the axially inward side is provided on the axial end surface of the vibration isolating base, and the axial center of the first convex portion is axially outward from the bottom of the straight portion. The anti-vibration bush according to claim 3 set.   An annular straight portion that is recessed toward the axially inward side is provided on the axial end surface of the vibration isolating base, and the axial center of the first convex portion is axially inward from the bottom of the straight portion. The anti-vibration bush according to claim 3 set.   The anti-vibration bushing according to claim 1, wherein the convex portion is an axial convex portion extending along an axial direction on an outer peripheral surface of the press-fit elastic portion, and a plurality of the axial convex portions are provided in the circumferential direction.   The anti-vibration bush according to claim 7, wherein the axial convex portion is provided from the thick axial end portion of the press-fit elastic portion to the thin axial central portion.

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