JP2014190509A - Vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration control device capable of increasing a ratio of a static spring constant of a rubber elastic body in a direction orthogonal to an axial direction of an outer cylinder and an inner cylinder.SOLUTION: A vibration control device comprises: an outer cylinder attached to one of a vibration generating part and a vibration receiving part and having the length from a center axis to an inner wall surface different around the center axis; an inner cylinder disposed in the inside of the outer cylinder to be coaxial with the outer cylinder, attached to the other of the vibration generating part and the vibration receiving part, and having the length from the center axis to an outer wall surface different around the center axis; and a rubber elastic body for connecting the inner wall surface of the outer cylinder and the outer wall surface of the inner cylinder to be elastically deformable in the state that the shortest part having the shortest length from the center axis to the inner wall surface of the outer cylinder and the longest part having the longest length from the center axis to the outer wall surface of the inner cylinder are confronted with each other.

Description

  The present invention relates to a vibration isolator.

  A so-called bush type vibration isolator having an outer cylinder, an inner cylinder, and a rubber elastic body that connects the outer cylinder and the inner cylinder so as to be elastically deformable is known. In this type of vibration isolator, a part of the outer cylinder is recessed inward, and the rubber thickness of the rubber elastic body is changed in a direction orthogonal to the axial direction of the outer cylinder and the inner cylinder of the vibration isolator, There is a vibration isolator in which the static spring constant of a rubber elastic body is changed around (for example, Patent Document 1).

  However, there is a limit to reducing the rubber thickness just by indenting the outer cylinder inward, and the ratio of the static spring constant of the rubber elastic body in the direction perpendicular to the axial direction of the outer cylinder and the inner cylinder should be increased. Has become difficult.

JP-A-6-280914

  An object of the present invention is to provide a vibration isolator capable of increasing the ratio of the static spring constant of a rubber elastic body in a direction orthogonal to the axial direction of the outer cylinder and the inner cylinder in consideration of the above matters.

  The vibration isolator according to claim 1 is attached to any one of the vibration generating unit and the vibration receiving unit, and the length of the outer cylinder from the central axis to the inner wall surface is different around the central axis; The inner cylinder is provided coaxially with the outer cylinder and attached to either the vibration generating part or the vibration receiving part, and the length from the central axis to the outer wall surface is different around the central axis. The cylinder, the shortest part having the shortest length from the central axis to the inner wall surface of the outer cylinder, and the longest part having the longest length from the central axis to the outer wall surface of the inner cylinder are opposed to each other. And a rubber elastic body for connecting the inner wall surface of the outer cylinder and the outer wall surface of the inner cylinder so as to be elastically deformable.

  In the vibration isolator according to the first aspect, the outer cylinder is attached to one of the vibration generating portion and the vibration receiving portion. Further, an inner cylinder is provided inside the outer cylinder when attached to either the vibration generating section or the vibration receiving section. Furthermore, the inner wall surface of the outer cylinder and the outer wall surface of the inner cylinder are connected by a rubber elastic body so as to be elastically deformable. As a result, when vibration is input to one of the outer cylinder and the inner cylinder, the rubber elastic body is elastically deformed and absorbs and attenuates the vibration, so that transmission of vibration to the other of the outer cylinder and the inner cylinder can be suppressed. .

  The outer cylinder is formed in a shape with different lengths from the central axis to the inner wall surface around the central axis, and the inner cylinder is formed in a shape with different lengths from the central axis to the outer wall surface around the central axis. Has been. Furthermore, the rubber elastic body is in a state where the shortest part from the center axis of the outer cylinder to the inner wall surface is the shortest part and the longest part from the center axis to the outer wall surface of the inner cylinder are opposed to each other. It is connected. Thereby, the rubber | gum thickness of the rubber elastic body between an outer cylinder and an inner cylinder becomes the thinnest in the site | part which the shortest part and the longest part have opposed. Here, since the static spring constant of the rubber elastic body depends on the rubber thickness of the rubber elastic body, the static spring constant of the rubber elastic body becomes larger in the portion where the rubber thickness is the thinnest than in other portions. The static spring constant of the rubber elastic body in the direction orthogonal to the axial direction of the outer cylinder and the inner cylinder can be varied. Also, compared to the case where only one of the outer cylinder and the inner cylinder has a different shape, the interval between the outer cylinder and the inner cylinder can be narrowed, and the rubber elastic body can be made thinner. The ratio can be increased.

  The anti-vibration device according to claim 2 is the anti-vibration device according to claim 1, wherein the shortest part and the longest part are provided on both sides of the central axis. To do.

  In the vibration isolator according to claim 2, the shortest part and the longest part are provided on both sides of the central axis. Thereby, the static spring constant of the rubber elastic body in the axial direction passing through the shortest part (longest part) and the central axis can be made larger than in the case where the shortest part and the longest part are provided only on one side. . That is, the ratio of the static spring constant in the direction orthogonal to the axial direction of the outer cylinder and the inner cylinder can be further increased.

  An anti-vibration device according to claim 3 is the anti-vibration device according to claim 1 or 2, wherein the outer cylinder protrudes inwardly and has an outer cylinder having a protruding portion serving as the shortest portion. The inner cylinder is an inner cylindrical body having a plane portion formed in parallel to each other on an outer wall surface and an arc portion formed between the plane portions and serving as the longest portion. And

  In the vibration isolator according to claim 3, the outer cylinder is an outer cylindrical body having a projecting portion facing inward, and the inner cylinder is between the plane portion and the plane portion formed in parallel to each other on the outer wall surface. And an arc portion formed on the inner cylindrical body. Thus, the configuration of the outer cylindrical body and the inner cylindrical body has a simple structure, so that it can be manufactured without requiring complicated processing.

  The vibration isolator according to claim 4 is the vibration isolator according to any one of claims 1 to 3, wherein one of the outer cylinder and the inner cylinder is attached to a vehicle body, and the outer cylinder And the other of the inner cylinders is a vibration isolator attached to a support member that supports a tire, wherein the shortest part and the longest part are located in a vehicle width direction.

  In the vibration isolator according to the fourth aspect, one of the inner cylinder and the outer cylinder is attached to the vehicle body, and the other is attached to a support member that supports the tire. The minimum diameter portion and the maximum diameter portion are located in the vehicle width direction of the vehicle. Thereby, since the static spring constant of the rubber elastic body in the vehicle width direction is increased, the rigidity in the vehicle width direction at the time of cornering is ensured, and the steering stability can be improved.

  Since this invention set it as said structure, it can enlarge the ratio of the static spring constant of the rubber elastic body in the direction orthogonal to the axial direction of an outer cylinder and an inner cylinder.

It is a perspective view which shows the vibration isolator which concerns on 1st Embodiment of this invention. It is a perspective view which shows the outer cylinder which comprises the vibration isolator which concerns on 1st Embodiment of this invention. It is the sectional view on the AA line of FIG. It is a perspective view which shows the inner cylinder which comprises the vibration isolator which concerns on 1st Embodiment of this invention. It is the BB sectional view taken on the line of FIG. It is sectional drawing which cut | disconnected the vibration isolator of FIG. 1 by XZ plane. It is sectional drawing which cut | disconnected the vibration isolator of FIG. 1 by XY plane. It is CC sectional view taken on the line of FIG. It is a top view which shows the sub-frame mechanism of the vehicle with which the vibration isolator which concerns on 1st Embodiment of this invention was attached. It is a perspective view which shows the vibration isolator which concerns on 2nd Embodiment of this invention. It is sectional drawing which cut | disconnected the vibration isolator of FIG. 9 by XY plane.

(First embodiment)
The vibration isolator 10 according to the first embodiment of the present invention will be described with reference to the drawings. In the following description, a direction parallel to the central axis CL of the vibration isolator 10 is described as an axial direction X, and two directions orthogonal to the axial direction are described as a Y direction and a Z direction, respectively.

  As shown in FIG. 1, the vibration isolator 10 according to this embodiment includes an outer cylinder 12, an inner cylinder 14 provided coaxially with the outer cylinder 12 inside the outer cylinder 12, This is a so-called bush type vibration isolator constituted by a rubber elastic body 16 that connects the outer cylinder 12 and the inner cylinder 14 so as to be elastically deformable.

  As shown in FIG. 2, the outer cylinder 12 has an outer cylindrical shape formed of steel, aluminum, or the like, and is on one end side with respect to the stepped portion 20 formed at the center portion in the axial direction X of the outer peripheral surface (outer wall surface) 12A. The large-diameter portion 12C and a small-diameter portion 12D on the other end side (see FIG. 6). Further, a notch 22 is formed in the Z direction at the end of the small diameter portion 12D.

  On the inner peripheral surface (inner wall surface) 12 </ b> B of the outer cylinder 12, a protruding portion 24 that protrudes inward facing the central axis CL is formed. The protrusions 24 are formed on both sides of the outer cylinder 12 in the Y direction, and the outer peripheral surface 12A of the outer cylinder 12 is recessed with a press or the like to protrude inward. For this reason, the site | part corresponding to the protrusion part 24 of 12 A of outer peripheral surfaces becomes the recessed part 28 dented inside. Further, the protruding portion 24 is formed with a length of about ¼ in the circumferential direction of the outer cylinder 12.

  In the present embodiment, the outer peripheral surface 12A of the outer cylinder 12 is recessed to form the protruding portion 24. However, if the protruding portion 24 can be formed on the inner peripheral surface 12B, the outer peripheral surface 12A need not be recessed. That is, the outer peripheral surface 12A of the outer cylinder 12 may be a surface without unevenness. Moreover, although the outer cylinder 12 was formed with metals, such as steel, you may form with resin. In this case, the outer cylinder 12 and the protruding portion 24 can be integrally formed by pouring a thermoplastic or thermosetting resin material into a dedicated mold.

  As shown in FIG. 3, the cross section of the protrusion 24 is curved so as to bulge outward in the radial direction, and the length from the central axis CL of the outer cylinder 12 to the inner peripheral surface 12B is different around the central axis CL. ing. The central portion 24A in the Z direction of the protruding portion 24 is the shortest portion having the shortest length from the central axis CL to the inner peripheral surface 12B. Here, in this embodiment, as an example, the length D1 from the central axis CL to the inner peripheral surface 12B of the outer cylinder 12 in the central portion 24A of the protruding portion 24 is 17.5 mm. Further, a length D2 from the central axis CL to the inner peripheral surface 12B of the outer cylinder 12 in the arc portion 30 where the protruding portion 24 is not formed is set to 25 mm.

  Although the length from the central axis CL to the central portion 24A of the protruding portion 24 may be shorter than 35 mm, the outer peripheral surface 12A of the outer cylinder 12 is recessed by a press as in this embodiment. Further, when forming the protruding portion 24, if the outer peripheral surface 12A is recessed too much, the thickness of the outer cylinder 12 in the protruding portion 24 becomes thin and the strength may be lowered. It is good to form it thickly.

  Moreover, in this embodiment, although the outer cylinder 12 was made into the cylindrical body, it is not restricted to this, Other shapes may be sufficient. For example, a rectangular tube may be used.

  As shown in FIG. 4, the inner cylinder 14 is an inner cylindrical body formed of steel, aluminum, or the like, similar to the outer cylinder 12, and is longer than the outer cylinder 12 in the axial direction X (see FIG. 6). . Further, the inner cylinder 14 has a planar portion 32 formed in parallel to each other with the central axis CL sandwiched between the outer peripheral surface 14A and an arc portion 34 formed between the planar portions 32 (see FIG. 5).

  Each of the plane portions 32 is located in the Z direction of the outer peripheral surface 14A, and is formed in a substantially rectangular shape with the axial direction X as the longitudinal direction in plan view. Further, the flat surface portion 32 extends from the end portion in the axial direction X slightly upward from the central portion in the axial direction X of the inner cylinder 14.

  As shown in FIG. 5, the arc portion 34 connects the end portions of the plane portion 32 in the Y direction. Here, the length from the central axis CL to the outer peripheral surface (outer wall) 14A of the inner cylinder 14 is different around the central axis CL. That is, the length from the central axis CL to the intermediate portion 32A in the Y direction of the plane portion 32 is the shortest, and the length from the central axis CL gradually increases from the intermediate portion 32A toward the end of the arc portion 34. Is getting longer.

  Further, the arc portion 34 is the longest portion having the longest length from the center axis CL to the outer peripheral surface 12A of the inner cylinder 14, and has a constant length in the arc portions on both sides. In the present embodiment, as an example, the length D3 from the central axis CL to the outer peripheral surface 14A of the arc portion 34 is 15 mm, and the length D4 from the central axis CL to the intermediate portion 32A of the plane portion 32 is 12.5 mm. . In addition, although the distance between the plane parts 32 which oppose may be shortened further, it is necessary to ensure a fixed thickness so that the thickness of the inner cylinder 14 may not become too thin.

  Step portions 36 and 38 are formed on one end portion in the axial direction X of the inner cylinder 14 and the inner peripheral surface 14B of the other end portion in the axial direction X (see FIG. 6). For this reason, the inner diameter of the inner cylinder 14 is the largest on one end side in the axial direction X and the smallest on the other end side.

  In addition, although the shape of the outer peripheral surface 12A of the inner cylinder 14 according to the present embodiment is a shape in which the ends of the arc portions 34 arranged to face each other are connected by the flat surface portion 32, the shape is not limited to this, and the outer shape in the Y direction Other shapes may be used as long as the diameter is the largest. For example, it may be oval long in the Y direction. Moreover, not only a cylindrical body but a square tube may be sufficient. Moreover, in this embodiment, as shown in FIG. 4, although the plane part 32 is extended from the edge part of the axial direction X to the slightly upper part from the center part of the axial direction X of the inner cylinder 14, it is not restricted to this. Instead, the planar portion 32 may be formed from one end portion in the axial direction X to the other end portion.

  As shown in FIG. 6, a rubber elastic body 16 made of rubber is vulcanized and bonded to the inner peripheral surface 12B of the outer cylinder 12 and the outer peripheral surface 14A of the inner cylinder 14, so that the outer cylinder 12 and the inner cylinder 14 is connected to be elastically deformable. The rubber elastic body 16 connects the outer cylinder 12 and the inner cylinder 14 with the projecting portion 24 (shortest portion) of the outer cylinder 12 and the arc portion 34 (longest portion) of the inner cylinder 14 facing each other. It is formed over the entire circumference around the central axis CL (see FIG. 8).

  On both ends of the rubber elastic body 16 in the axial direction X, a currant 40 is formed as a concave portion in which the rubber elastic body 16 is recessed in the axial direction X. By forming the currant 40, the volume of the rubber elastic body 16 can be reduced and the rigidity of the rubber elastic body 16 can be lowered. On the other hand, the currant 40 is clogged with sand and mud, and the vibration-proof performance is impaired. There is a fear. For this reason, the depth of the currant 40 is good to form in the minimum necessary depth.

  As shown in FIG. 7, the cross-sectional shape of the protruding portion 24 formed on the inner peripheral surface 12 </ b> B of the outer cylinder 12 is a rounded shape with no corners. For this reason, the pressure received from the rubber elastic body 16 is suppressed from concentrating on the protrusion 24. Similarly, the boundary between the outer peripheral surface 12A of the outer cylinder 12 and the recess 28 has an R shape with no corners, thereby suppressing stress concentration.

  Here, referring to FIG. 8, the rubber thickness Ty in the Y direction of the rubber elastic body 16 is compared with the rubber thickness Tz in the Z direction. The rubber thickness Ty of the rubber elastic body 16 in the Y direction of the vibration isolator 10 is such that the inner peripheral surface 12B of the outer cylinder 12 and the arc portion 34 (longest portion) in the intermediate portion 24A of the protruding portion 24 (shortest portion). It is the rubber thickness between the outer peripheral surface 14A of the inner cylinder 14 in the part, and is the thinnest in the circumferential direction. As described above, the length D1 from the central axis CL to the inner peripheral surface 12B of the outer cylinder 12 in the intermediate portion 24A of the protruding portion 24 is 17.5 mm, and from the central axis CL to the outer peripheral surface 14A of the arc portion 34. Since the length D3 of the rubber elastic body 16 is 15 mm, the rubber thickness Ty in the Y direction of the rubber elastic body 16 is D1−D3 = 2.5 mm.

  On the other hand, the rubber thickness Tz of the rubber elastic body 16 in the Z direction of the vibration isolator 10 is a rubber between the inner peripheral surface 12B of the outer cylinder 12 in the arc portion 30 and the intermediate portion 32A of the flat portion 32 of the inner cylinder 14. It is thick and thickest in the circumferential direction. The length D2 from the central axis CL to the inner peripheral surface 12B of the outer cylinder 12 in the circular arc part 30 is 25 mm, and the length D4 from the central axis CL to the intermediate part 32A of the flat part 32 is 12.5 mm. Therefore, the rubber thickness Tz in the Z direction of the rubber elastic body 16 is D2−D4 = 12.5 mm.

Here, the static spring constant Ks [kgf / cm] of the rubber elastic body 16 is expressed as follows using the rubber thickness T [cm] of the rubber elastic body 16 and the pressure receiving area A [cm ² ] of the rubber elastic body 16. (1). Eap is the apparent Young's modulus [kgf / cm ² ].

... (1)

  From the above equation (1), it can be seen that the static spring constant Ks of the rubber elastic body 16 is inversely proportional to the rubber thickness T of the rubber elastic body 16 and proportional to the pressure receiving area A of the rubber elastic body 16. That is, when the pressure receiving area A is the same area, the static spring constant Ks decreases as the rubber thickness T of the rubber elastic body 16 increases, and the static spring constant Ks increases as the rubber thickness T decreases.

  In the present embodiment, since the pressure receiving surface in the Y direction of the vibration isolator 10 is the arc portion 34 and the pressure receiving surface in the Z direction is the flat portion 32, the pressure receiving area A is more in the Y direction than in the Z direction. Somewhat big. Further, as described above, the rubber thickness Tz in the Z direction is 25 mm, whereas the rubber thickness Ty in the Y direction is 5 mm, so that the thickness is 1/5 of Tz. Therefore, even if the influence of the spring in the shear direction is taken into consideration, the static spring constant Ks in the Y direction is about three times the static spring constant in the Z direction.

  Next, the subframe mechanism 100 to which the vibration isolator 10 according to the present embodiment is attached will be described. As shown in FIG. 9, one end of the lower arm 102 as a support member constituting the subframe mechanism 100 is connected to the tire via a knuckle (not shown) attached to the drive shaft. The lower arm 102 is a plate-like member curved inward in the vehicle width direction, and a through hole 102 </ b> A that penetrates in the vehicle vertical direction is formed at the other end of the lower arm 102. The vibration isolator 10 is press-fitted into the through hole 102A, and the lower arm 102 and the outer cylinder 12 are fixed. At this time, the outer cylinder 12 is press-fitted into the lower arm 102 in a state where the protruding portion 24 (see FIG. 1) formed on the outer cylinder 12 is positioned in the vehicle width direction. Further, a connecting shaft (not shown) is passed through the through hole 18 of the inner cylinder 14, and the inner cylinder 14 is fixed to the sub-frame 104 on the vehicle main body side via this connecting shaft.

  A cylindrical bracket 102B having openings at both ends in the vehicle front-rear direction is formed at an intermediate portion of the lower arm 102, and the vibration isolator 10 is press-fitted into the bracket 102B. At this time, the outer cylinder 12 is press-fitted into the bracket 102B in a state where the protruding portion 24 (see FIG. 1) is positioned in the vehicle width direction. Further, a connecting rod 106 with a bolt hole is passed through the through hole 18 of the inner cylinder 14, and a bolt is inserted into the bolt hole of the connecting rod 106 to fix the inner cylinder 14 to the subframe 104. Has been. In this way, the two vibration isolators 10 are fixed to the lower arms 102 on both sides in the vehicle width direction.

Next, the operation of the vibration isolator 10 according to the present embodiment will be described. When the vehicle to which the vibration isolator 10 is attached is traveling, the vibration that the tire 101 receives from the road surface is transmitted to the outer cylinder 12 of the vibration isolator 10 via the lower arm 102. Then, vibration is input from the outer cylinder 12 to the rubber elastic body 16, and the rubber elastic body 16 is elastically deformed to attenuate and absorb the vibration. Thereby, it can suppress that a vibration transmits from the outer cylinder 12 to a vehicle main body.

  Further, since the static spring constant Ks of the rubber elastic body 16 in the Y direction in which the protruding portion 24 is formed is the largest in the circumferential direction, the amount of displacement when a force is applied in the Y direction is determined according to Hooke's law. In other words, the rigidity of the rubber elastic body 16 in the Y direction is the highest. Since the protrusion 24 is positioned in the vehicle width direction, rigidity in the vehicle width direction is ensured during cornering, and steering stability can be improved.

  Furthermore, since the static spring constant Ks of the rubber elastic body 16 in the Z direction in which the protrusions 24 are not formed is the smallest in the circumferential direction, the rigidity of the rubber elastic body 16 in the Z direction is the largest in the circumferential direction. Lower. Since the Z direction of the vibration isolator 10 that is press-fitted into the bracket 102B of the lower arm 102 is the vehicle vertical direction, the vehicle vertical direction rigidity is reduced, and the riding comfort of the vehicle can be improved. As described above, by configuring the rubber elastic body 16 so that the static spring constant Ks is different between the Y direction and the Z direction, it is possible to achieve both steering stability and riding comfort of the vehicle.

  In the present embodiment, the outer cylinder 12 is fixed to the lower arm 102 as a vibration generating part, and the inner cylinder 14 is fixed to the sub-frame 104 on the vehicle main body side as a vibration receiving part. The inner cylinder 14 may be fixed to the lower arm 102, and the outer cylinder 12 may be fixed to the subframe 104. Further, the vibration isolator 10 may be disposed between the vehicle main body and the engine and used as an engine mount. Furthermore, as long as the structure includes a vibration generating unit and a vibration receiving unit, the vibration isolating device 10 is not limited to the vehicle. It may be attached to other vehicles and devices.

(Second Embodiment)
Next, the vibration isolator according to the second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected about the structure same as 1st Embodiment, and description is abbreviate | omitted. As shown in FIG. 10, the vibration isolator 50 according to this embodiment includes an outer cylinder 52, an inner cylinder 14 provided coaxially with the outer cylinder 52 inside the outer cylinder 52, and the outer cylinder 52 and the inner cylinder. And a rubber elastic body 56 that couples 14 to each other so as to be elastically deformable. Here, the outer cylinder 52 is press-fitted into a cylindrical bracket 102B, and is attached to a vehicle main body (not shown) as a vibration receiving portion via the bracket 102B. A lower arm 102 as a vibration generating portion is attached to the through hole 18 formed in the inner cylinder 14 (see FIG. 9).

  The outer cylinder 52 is a cylindrical body formed of steel, aluminum or the like, and two sets of protrusions 57 formed by denting the outer peripheral surface 52 are provided in the axial direction X on the inner peripheral surface 52B of the outer cylinder 52. (See FIG. 11). Each of the protrusions 57 extends in the circumferential direction, and is formed by denting the outer peripheral surface 52A of the outer cylinder 52 with a press or the like. For this reason, the site | part corresponding to the protrusion part 57 of 52 A of outer peripheral surfaces becomes the recessed part 58 dented inside.

  As shown in FIG. 11, a rubber elastic body 56 is vulcanized and bonded to the inner peripheral surface 52B of the outer cylinder 52 and the outer peripheral surface 12A of the inner cylinder 14, and the outer cylinder 52 and the inner cylinder 14 are elastically deformed. It is connected as possible. Here, the positional relationship between the outer cylinder 52 and the inner cylinder 14 is the same as that in FIG. 8, and the intermediate portion 57 </ b> A of the protruding portion 57 of the outer cylinder 52 and the arc portion 34 of the inner cylinder 14 face each other. Yes. For this reason, the rubber thickness of the rubber elastic body 56 is the thinnest in the Y direction in which the protrusions 57 are formed. Other configurations are the same as those of the first embodiment.

  In the vibration isolator 50 according to the present embodiment, since two sets of the protruding portions 57 of the outer cylinder 52 are formed, the rigidity in the Y direction can be further improved as compared with the vibration isolator 10 according to the first embodiment. Accordingly, by attaching the protruding portion 57 so as to be positioned in the vehicle width direction, rigidity in the vehicle width direction during cornering is ensured, and steering stability is improved.

  Further, when trying to press a wide area of the outer peripheral surface 52A of the outer cylinder 52 with a press machine, the entire outer cylinder 12 may be deformed. However, as in the vibration isolator 50 according to the present embodiment, the protruding portion 57 is provided. When forming a plurality, since force is applied locally, it is possible to suppress deformation of the entire outer cylinder 52.

  Although the first and second embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and can of course be implemented in various modes without departing from the gist of the present invention. It is. For example, in FIG. 8, the cross-sectional shape of the protrusion 24 may be a shape in which the inside is convex.

10 Vibration isolator 12 Outer cylinder 12B Inner peripheral surface (inner wall)
14 Inner cylinder 14A Outer peripheral surface (outer wall)
16 Rubber elastic body 24 Protruding part 24A Center part (shortest part)
32 Plane part 34 Arc part (longest part)
50 Vibration isolator 52 Outer cylinder 52B Inner peripheral surface (inner wall)
56 Rubber elastic body 57 Protruding part 102 Lower arm (vibration generating part)
104 Subframe (vibration receiver)
CL center axis

Claims (4)

An outer cylinder attached to either one of the vibration generating part and the vibration receiving part, and having a different length from the central axis to the inner wall surface around the central axis;
Provided coaxially with the outer cylinder on the inner side of the outer cylinder and attached to either the vibration generating part or the vibration receiving part, and the length from the central axis to the outer wall surface is different around the central axis. An inner cylinder,
In the state where the shortest part from the central axis to the inner wall surface of the outer cylinder is the shortest part and the longest part from the central axis to the outer wall surface of the inner cylinder are opposed to each other, A rubber elastic body that connects the inner wall surface of the outer cylinder and the outer wall surface of the inner cylinder in an elastically deformable manner;
An anti-vibration device comprising:   The vibration isolator according to claim 1, wherein the shortest part and the longest part are provided on both sides of the central axis. The outer cylinder is an outer cylindrical body that protrudes inward and has a protruding portion that becomes the shortest portion,
The inner cylinder is an inner cylinder having a plane part formed in parallel to each other on an outer wall surface, and an arc part formed between the plane parts and serving as the longest part. The vibration isolator according to 1 or 2. One of the outer cylinder and the inner cylinder is attached to a vehicle body, and the other of the outer cylinder and the inner cylinder is a vibration isolator attached to a support member that supports a tire,
The vibration isolator according to any one of claims 1 to 3, wherein the shortest part and the longest part are located in a vehicle width direction.