JP2008256077A - Anti-vibration bushing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-vibration bushing capable of reducing a spring constant in the prying direction, increasing the spring constant in the direction perpendicular to the axis, furthermore capable of making spring characteristics linear closely for the load input in the direction perpendicular to the axis. <P>SOLUTION: An intermediate cylinder 16 is provided between an inner cylinder 12 and an outer cylinder 14. An inside elastic body 18 to connect the inner cylinder 12 and the intermediate cylinder 16, and an outside elastomer 20 to connect the intermediate cylinder 16 and the outer cylinder 14 are formed of a rubber elastomer. A first bulging-out portion 22 bulging out in the outward Y1 side perpendicular to the axis is formed at the axial center of the inner cylinder 12. A second bulging-out portion 26 bulging out in the outward Y1 side perpendicular to the axis is formed at the axial center of the intermediate cylinder 16 to surround thereof. A plurality of through-holes 38 passing through the intermediate cylinder 16, and connecting the inside elastic portion 18 and the outside elastic portion 20 are arranged in parallel in the circumference C in the second bulging-out portion 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

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 a rubber-like elastic body to be bonded together.

  By the way, in the vibration isolating bush used for 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 twisting direction and the torsion direction is increased in order to improve ride comfort and handling 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 anti-vibration bushes have been developed. In order to further increase the spring constant in the direction perpendicular to the axis, a configuration in which an intermediate cylinder is provided between an inner cylinder and an outer cylinder in a bulge type vibration-proof bush is known (see Patent Document 1 below).

On the other hand, in an anti-vibration bush having an intermediate cylinder between the inner cylinder and the outer cylinder, an inner elastic portion made of a rubber-like elastic body interposed between the inner cylinder and the intermediate cylinder, and the intermediate cylinder and the outer cylinder There is known a technique in which a through hole or a slit for connecting an outer elastic portion made of a rubber-like elastic body interposed between the intermediate cylinder and the intermediate cylinder is provided (see Patent Documents 2 and 3 below).
Japanese Patent Laid-Open No. 09-100811 JP 09-072365 A Japanese Unexamined Patent Publication No. 2000-065112

  As in the vibration isolating bush disclosed in Patent Document 1, the bulge type anti-vibration bush including the intermediate cylinder has the following problems. That is, in this type of vibration isolator, after the vulcanization molding of the rubber-like elastic body, the outer cylinder is subjected to a drawing process in order to eliminate molding distortion. Although the outer elastic part on the outer side is compressed, the inner elastic part inside the intermediate cylinder is not compressed because the diameter of the intermediate cylinder is hardly reduced. Therefore, the outer elastic portion has a higher spring constant in the direction perpendicular to the axis due to compression than the inner elastic portion. When the spring constants of the outer elastic portion and the inner elastic portion are different in this way, when a load is input in the direction perpendicular to the axis with respect to the vibration isolating bush, the initial rise of the load-deflection curve is caused by the inner elastic portion having a low spring constant. After that, the spring characteristic becomes non-linear so that the slope of the curve becomes tight, and an excellent anti-vibration characteristic cannot be obtained.

  In Patent Document 2 and Patent Document 3, the through hole or slit provided in the intermediate cylinder allows the rubber material to flow through the through hole when the rubber-like elastic body is molded, and acts on the intermediate cylinder. Pressure is reduced, or the compression force of the outer elastic part is transmitted to the entire inner elastic part through the slit during pre-compression after vulcanization, and the inner elastic part is pre-compressed uniformly in the axial direction. Is to do. Therefore, the through holes or slits are evenly distributed throughout the entire axial direction of the intermediate cylinder, and therefore do not suggest any features of the present invention described later.

  The present invention provides an anti-vibration bushing that can reduce the spring constant in the twisting direction while increasing the spring constant in the direction perpendicular to the axis, and can bring the spring characteristics close to linear with respect to the load input in the direction perpendicular to the axis. The purpose is to provide.

  An anti-vibration bush according to the present invention includes a shaft member, an outer cylinder that surrounds the shaft member in an axial parallel, an intermediate cylinder that is provided between the shaft member and the outer cylinder and surrounds the shaft member in an axial parallel manner, An inner elastic portion made of a rubber-like elastic body that is bonded to the outer peripheral surface of the shaft member and the inner peripheral surface of the intermediate tube and connects the shaft member and the intermediate tube, and the outer peripheral surface of the intermediate tube and the outer tube An anti-vibration bush comprising an outer elastic portion made of a rubber-like elastic body that is bonded to the inner peripheral surface of the shaft and connects the intermediate cylinder and the outer cylinder. A second bulging portion formed at a first bulging portion that bulges outward in the direction and an axially central portion of the intermediate cylinder surrounding the first bulging portion bulges outward in the direction perpendicular to the axis. A first bulge is formed on the bulging portion, and an inner peripheral surface of the second bulging portion corresponds to a first convex surface of the first bulging portion. An inner peripheral surface portion of the outer cylinder that is formed on a surface and surrounds the second bulging portion is formed as a second concave surface corresponding to a second convex surface of the outer peripheral surface of the second bulging portion, and the intermediate cylinder is A plurality of through-holes that penetrate and connect the inner elastic portion and the outer elastic portion are arranged in the circumferential direction in the second bulging portion.

  According to the above configuration, the inner elastic portion between the first convex surface of the shaft member and the first concave surface of the intermediate cylinder and the second convex surface of the intermediate cylinder and the second concave surface of the outer cylinder when displaced in the twisting direction. Since the outer elastic part in between is mainly subjected to shear deformation, the spring constant in the twisting direction can be reduced. In addition, since it is a bulge type, a spring constant in the direction perpendicular to the axis can be secured in the first place, and the spring constant in the direction perpendicular to the axis can be further increased by providing an intermediate cylinder.

  Moreover, the outer elastic part outside the intermediate cylinder is compressed by the drawing process of the outer cylinder and the spring constant becomes high, but at the time of the drawing process, the inner elastic part has an axial center inside the second bulge part. In the portion, by providing the through hole, the spring constant is increased by being compressed in the direction perpendicular to the axis. Therefore, the spring characteristics can be made closer to linear with respect to the load input in the direction perpendicular to the axis.

  Providing the through hole at the top of the second bulging portion is more effective in increasing the spring constant in the direction perpendicular to the axis of the inner elastic portion when the outer cylinder is drawn.

  In the above configuration, when the inner elastic part is formed to have a larger axial dimension than the outer elastic part, the following operational effects are obtained. That is, by setting the axial dimension of the outer elastic portion to be compressed more greatly when the outer cylinder is drawn, the increase in the spring constant due to the drawing of the outer elastic portion can be compensated for in the inner elastic portion. Therefore, the spring characteristics of the inner and outer elastic portions can be set to be equal, and the spring characteristics can be made more linear with respect to the load input in the direction perpendicular to the axis.

  In the above configuration, the first bulging portion is formed in a spherical belt shape bulging outward in the direction perpendicular to the axis, the first convex surface is formed as a first spherical convex surface, and the second bulging portion is a shaft. The first concave surface is formed as a first spherical concave surface, the second convex surface is formed as a second spherical convex surface, and is formed in a spherical belt shape bulging outward in a right angle direction. The two concave surfaces are preferably formed as the second spherical concave surface corresponding to the second spherical convex surface in order to more effectively reduce the spring constant in the twisting direction.

  With the vibration-isolating bushing of the present invention, the spring constant in the direction perpendicular to the axis can be increased, the spring constant in the direction of twisting can be reduced, and the spring characteristics can be made closer to linear with respect to the load input in the direction perpendicular to the axis. 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 one 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.

  As shown in FIGS. 1 and 2, 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 an inner cylinder 12 at an intermediate position between the inner cylinder 12 and the outer cylinder 14. An intermediate cylinder 16 that surrounds the cylinder 12 in an axially parallel and coaxial manner, an inner elastic portion 18 formed of a rubber elastic body interposed between the inner cylinder 12 and the intermediate cylinder 16, and between the intermediate cylinder 16 and the outer cylinder 14. The outer elastic part 20 which consists of the interposed rubber elastic body is provided. Then, as shown in FIG. 8, the inner cylinder 12 is fixed to the bracket 1 by tightening with a fastening member (not shown) such as a bolt in a state where both end faces are sandwiched between the brackets 1 of the suspension member. The outer cylinder 14 is fixed by being press-fitted into the cylindrical holder 3 of the link member 2, whereby the anti-vibration bush 10 connects the link member 2 and the bracket 1 on the suspension member side in an anti-vibration manner.

  The inner cylinder 12 is a metal cylindrical member, and as shown in FIG. 4, a first bulge that bulges in a curved shape over the entire circumference toward the outer side Y <b> 1 in the axially perpendicular direction at the center in the axial direction X. A protruding portion 22 is provided. In this example, the first bulging portion 22 has a spherical shape, and therefore the first convex surface 24 that is the outer peripheral surface of the first bulging portion 22 forms a spherical convex surface (referred to as a first spherical convex surface 24). Yes. Specifically, the first spherical convex surface 24 has a spherical belt shape that forms the axial central portion of the spherical surface having the center P on the axis A of the inner cylinder 12, and the general cylindrical portions at both axial ends of the inner cylinder 12. It is formed smoothly and continuously from the outer peripheral surface 12A of the straight cylindrical portion having a constant outer diameter.

  The intermediate cylinder 16 is a thin metal cylindrical member. As shown in FIGS. 1, 6, and 7, the central portion of the axial direction X surrounding the first bulging portion 22 is on the outer side in the direction perpendicular to the axis Y1. The second bulging portion 26 bulging in a curved shape over the entire circumference is bent. In this example, the second bulging portion 26 has a spherical belt shape, and therefore the first concave surface 28 that is the inner peripheral surface of the second bulging portion 26 is the first spherical convex surface 24 of the first bulging portion 22. And a spherical concave surface (referred to as a first spherical concave surface 28) having a concentric shape (that is, having a common center P). In addition, the second convex surface 30 that is the outer peripheral surface of the second bulging portion 26 forms a spherical convex surface (referred to as a second spherical convex surface 30) concentric with the first spherical convex surface 24 of the first bulging portion 22. .

  The first spherical concave surface 28 is formed smoothly and continuously from the inner peripheral surface 16A of the general cylindrical portion (straight cylindrical portion having a constant inner and outer diameter) at both axial ends of the intermediate tube 16. The second spherical convex surface 30 is formed smoothly and continuously from the outer peripheral surface 16B of the general cylindrical portion of the intermediate cylinder 16.

  The outer cylinder 14 is a metal cylindrical member, and as shown in FIGS. 2 and 5, the outer shape is a circular cross section, and the outer peripheral surface 14 </ b> A has a diameter that is constant in the axial direction X. Yes. As shown in FIG. 1, the inner peripheral surface portion of the outer cylinder 14 surrounding the second bulging portion 26 corresponds to the second spherical convex surface 30 on the outer peripheral surface side of the second bulging portion 26 and is outside the direction perpendicular to the axis. The second concave surface 32 is depressed on the side of the direction Y1. In this example, the second concave surface 32 is formed as a spherical concave surface concentric with the second spherical convex surface 30 (referred to as a second spherical concave surface 32). Specifically, the inner peripheral surface 14B in the central portion of the outer cylinder 14 has a shape perpendicular to the axially outward Y1 side so as to follow the second spherical convex surface 30 with a certain distance in the shape after drawing described later. It is recessed in the spherical concave surface 32 that is recessed.

  In addition, the 2nd spherical concave surface 32 is gently formed continuously from the internal peripheral surface 14B of the general cylinder part (straight cylindrical part with a constant internal diameter) in the axial direction both ends of the outer cylinder 14. As shown in FIG. Further, as shown in FIG. 5, in the state before drawing, the second spherical concave surface 32 is not a strict sphere, but the center P is at a position shifted in the direction perpendicular to the axis Y from the axis A of the outer cylinder 14. Yes, by drawing in the diameter-reducing direction, the center P is formed in a spherical shape located on the axis A as shown in FIG.

  The inner elastic portion 18 is a cylindrical rubber member that connects the inner cylinder 12 and the intermediate cylinder 16, and the outer cylinder 12 A including the first spherical convex surface 24 and the intermediate cylinder 16 including the first spherical concave surface 28. Are vulcanized and bonded to the inner peripheral surface 16A. The outer elastic portion 20 is a cylindrical rubber member that connects the intermediate cylinder 16 and the outer cylinder 14, and the outer cylinder 14 including the outer peripheral surface 16 </ b> B of the intermediate cylinder 16 including the second spherical convex surface 30 and the second spherical concave surface 32. Are vulcanized and bonded to the inner peripheral surface 14B. Both elastic parts 18 and 20 are formed of the same rubber material.

  The inner elastic portion 18 is not only filled between the first spherical convex surface 24 and the first spherical concave surface 28, but both end portions 18 </ b> A and 18 </ b> A are axially outward X <b> 1 side from the first spherical convex surface 24. The inner cylindrical portion 12B and the intermediate cylindrical portion 16C closer to the axially outward X1 side than the first spherical concave surface 28 are extended to the axially outward X1 side. Similarly, the outer elastic portion 20 is not only filled between the second spherical convex surface 30 and the second spherical concave surface 32, but both end portions 20 </ b> A and 20 </ b> A are axially outside of the second spherical convex surface 30. The intermediate cylindrical portion 16C on the side of the side X1 and the outer cylindrical portion 14C on the side of the axially outward X1 with respect to the second spherical concave surface 32 are extended to the axially outward X1 side.

  The axial end surfaces of both elastic portions 18 and 20 are provided with annular straight portions 34 and 36 that are recessed in an arcuate cross section toward the axially inward X2 side. The straight portion 34 of the inner elastic portion 18 is formed with a shallower depth in the axial direction X than the straight portion 36 of the outer elastic portion 20, whereby the axial dimension D 1 of the inner elastic portion 18 is outside. The elastic part 20 is formed larger than the axial dimension D2 (that is, D1> D2).

  As shown in FIG. 7, the intermediate cylinder 16 is provided with a circular through hole 38 in the second bulging portion 26. The through hole 38 is provided in the top portion 26A of the second bulging portion 26 at the center in the axial direction X, and is not provided in the intermediate cylinder portion 16C on the axially outward X1 side from the second bulging portion 26. . And as shown in FIG. 1, the inner side elastic part 18 and the outer side elastic part 20 are connected by axial direction center part 18B, 20B through this through-hole 38. As shown in FIG.

  As shown in FIG. 6, a plurality of through holes 38 are provided at equal intervals in the circumferential direction C of the intermediate cylinder 16, and in this example, six through holes 38 are provided every 60 °.

  When manufacturing the vibration isolating bushing 10, first, as shown in FIG. 4, the inner cylinder 12 having the first bulging portion 22 and the second spherical concave surface 32 on the inner peripheral surface 14B as shown in FIG. The outer cylinder 14 having the inner cylinder 16 and the intermediate cylinder 16 having the second bulging portion 26 as shown in FIGS.

  Next, the inner cylinder 12, the outer cylinder 14, and the intermediate cylinder 16 are placed in a molding die (not shown), and a rubber material is injected into the molding die so that the inner cylinder 12 and the outer cylinder 14 are placed inside. The elastic part 18 and the outer elastic part 20 are vulcanized. At that time, the rubber material is injected from two injection holes 42 and 42 (see FIG. 2) opposed to each other in the diameter direction provided on the end surface in the axial direction in the cavity for molding the outer elastic portion 20. The injected rubber material flows into the inner cavity through a plurality of through holes 38 provided in the intermediate cylinder 16 to form the inner elastic portion 18. As a result, the vulcanized molded body before drawing shown in FIG. 3 is obtained.

  Thereafter, the outer cylinder 14 of the vulcanized molded body is subjected to a drawing process to reduce the diameter of the outer cylinder 14, whereby the vibration isolating bush 10 shown in FIG. 1 is obtained. By the drawing process, the outer elastic portion 20 is compressed in the direction perpendicular to the axis Y, and the spring constant is increased. On the other hand, the inner elastic portion 18 is not basically compressed in the direction perpendicular to the axis Y because the intermediate cylinder 16 is not reduced in diameter due to the presence of the outer elastic portion 20.

  However, in this embodiment, since the through hole 38 is provided in the second bulging portion 26, the axial center portion 18 </ b> B of the inner elastic portion 18 corresponding to the inside of the through hole 38 is compressed in the direction perpendicular to the axis Y. This increases the spring constant. In addition, since the through hole is not provided in the intermediate cylinder portion 16C on the axially outward X1 side from the second bulging portion 26, the inner elastic portion 18 is compressed by the end portion 18A during the drawing process. Therefore, it is possible to avoid an increase in the spring constant of the inner elastic portion 18 in the twisting direction Z.

  Further, since the inner elastic portion 18 is set to have a larger axial dimension than the outer elastic portion 20 (D1> D2), an increase in the spring constant of the outer elastic portion 20 due to the drawing process is determined in the inner elastic portion 18. The spring constant in the direction perpendicular to the axis Y can be set equally between the inner elastic portion 18 and the outer elastic portion 20.

  Therefore, the spring characteristic can be made close to linear with respect to the load input in the direction Y perpendicular to the axis with respect to the vibration isolating bush 10, and the desired vibration isolating characteristic can be exhibited. Further, by making the inner and outer spring constants equal, it is possible to improve the durability of the vibration isolating bush 10 against the load input in the direction perpendicular to the axis Y.

  Further, when the vibration isolating bush 10 is displaced in the twisting direction Z, the inner elastic portion 18 between the first spherical convex surface 24 of the inner cylinder 12 and the first spherical concave surface 28 of the intermediate cylinder 16, and the intermediate cylinder The outer elastic portion 20 between the 16 second spherical convex surfaces 30 and the second spherical concave surface 32 of the outer cylinder 14 is mainly subjected to shear deformation. Therefore, the spring constant in the twisting direction Z can be effectively reduced.

  Further, with respect to the displacement in the axial direction X, the inner elastic portion 18 and the outer elastic portion 20 are subjected not only to shear deformation but also to compressive deformation between the spherical convex surfaces 24 and 30 and the spherical concave surfaces 28 and 32. Therefore, the spring constant in the axial direction X can be increased. In addition, the provision of the intermediate cylinder 16 increases the spring constant in the direction Y perpendicular to the axis. Therefore, when the spring constant in the direction perpendicular to the axis Y is set to be equal to that in the case where the intermediate cylinder is not provided, a softer rubber elastic body can be used, whereby the spring constant in the torsional direction N can be lowered. .

  As described above, the vibration isolating bush 10 can effectively reduce the spring constants in the twisting direction Z and the torsional direction N while securing the spring constants in the axial direction X and the axially perpendicular direction Y. Therefore, in the suspension device, riding comfort can be greatly improved while ensuring steering stability.

  In the present embodiment, since the axial dimension of the inner elastic portion 18 is set larger than that of the outer elastic portion 20 (D1> D2), the inner elastic portion 18 having a short circumference is bonded to the inner cylinder 12. A large area can be secured correspondingly, and durability can be improved from this point.

  INDUSTRIAL APPLICABILITY The present invention can be used for various types of anti-vibration bushes such as an anti-vibration bush used in an automobile suspension device and a cylindrical anti-vibration bush as an engine mount.

Sectional drawing of the anti-vibration bush which concerns on embodiment (II sectional view taken on the line of FIG. 2). The side view of the vibration isolating bush. Sectional drawing before the drawing process of the vibration isolating bush. Sectional drawing of the inner cylinder of the vibration isolating bush. Sectional drawing of the outer cylinder of the vibration isolating bush. The side view of the intermediate | middle cylinder of the vibration isolating bush. VII-VII sectional view taken on the line of FIG. Sectional drawing which shows the assembly | attachment state of the vibration isolating bush.

Explanation of symbols

10 ... Anti-vibration bush,
DESCRIPTION OF SYMBOLS 12 ... Inner cylinder (shaft member), 12A ... Outer peripheral surface 14 ... Outer cylinder, 14B ... Inner peripheral surface 16 ... Intermediate | middle cylinder, 16A ... Inner peripheral surface, 16B ... Outer peripheral surface,
18 ... inner elastic part,
20 ... the outer elastic part,
22 ... 1st bulging part,
24 ... first spherical convex surface (first convex surface),
26 ... 2nd bulge part, 26A ... Top part 28 ... 1st spherical concave surface (1st concave surface),
30 ... 2nd spherical convex surface (2nd convex surface),
32 ... second spherical concave surface (second concave surface),
38 ... through hole,
C ... circumferential direction,
D1: axial dimension of the inner elastic part, D2: axial dimension of the outer elastic part,
X ... Axial direction,
Y ... axis perpendicular direction, Y1 ... axis perpendicular direction outward

Claims (4)

A shaft member;
An outer cylinder surrounding the shaft member in parallel to the axis;
An intermediate cylinder that is provided between the shaft member and the outer cylinder and surrounds the shaft member in an axis-parallel manner;
An inner elastic portion made of a rubber-like elastic body that is bonded to the outer peripheral surface of the shaft member and the inner peripheral surface of the intermediate tube and connects the shaft member and the intermediate tube;
An outer elastic portion made of a rubber-like elastic body that is bonded to the outer peripheral surface of the intermediate tube and the inner peripheral surface of the outer tube and connects the intermediate tube and the outer tube;
An anti-vibration bush comprising:
A central portion in the axial direction of the shaft member is formed at a first bulging portion that bulges outward in a direction perpendicular to the axis, and a central portion in the axial direction of the intermediate cylinder surrounding the first bulging portion is formed. The second bulging portion is formed in a second bulging portion bulging outward in the direction perpendicular to the axis, and the inner peripheral surface of the second bulging portion is a first concave surface corresponding to the first convex surface of the first bulging portion. Formed and an inner peripheral surface portion of the outer cylinder surrounding the second bulging portion is formed on a second concave surface corresponding to the second convex surface of the outer peripheral surface of the second bulging portion,
A plurality of through holes that penetrate the intermediate cylinder and connect the inner elastic portion and the outer elastic portion are arranged in the circumferential direction in the second bulging portion,
Anti-vibration bush.   The anti-vibration bush according to claim 1, wherein the through hole is provided in a top portion of the second bulge portion.   The anti-vibration bush according to claim 1 or 2, wherein the inner elastic portion is formed to have a larger axial dimension than the outer elastic portion. The first bulging portion is formed in a spherical belt shape bulging outward in a direction perpendicular to the axis, and the first convex surface is formed as a first spherical convex surface;
The second bulging portion is formed in a spherical band shape that bulges outward in the direction perpendicular to the axis, the first concave surface is formed as a first spherical concave surface, and the second convex surface is formed as a second spherical convex surface. And
The anti-vibration bush according to any one of claims 1 to 3, wherein the second concave surface of the outer cylinder is formed as a second spherical concave surface corresponding to the second spherical convex surface.

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