Suspension bushings

Abstract

To provide a suspension bush of a novel structure capable of tuning a ratio of a spring constant in a hollow direction and a spring constant in a solid direction with high accuracy, without deteriorating durability.SOLUTION: A rubber elastic body has: a pair of hollow parts arranged opposite to each other across an inner shaft member in a first radial direction, and passing through an inner shaft part in an axial direction; and a pair of non-through holes arranged opposite to each other in a second radial direction perpendicular to the first radial direction, and extending from both axial end surfaces to an axial intermediate region, where the pair of holes is formed in an arc shape projecting outward in the second radial direction. A hole diameter in the second radial direction of the pair of non-through holes is set smaller than a hole diameter in the first radial direction of the pair of hollow parts, and each of the pair of non-through holes is arranged on an outer cylindrical member side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention has a structure in which an inner shaft member and an outer cylindrical member, which are arranged radially spaced apart, are connected by a rubber elastic body, and can be suitably used as a suspension bushing for automobiles. [Background technology]

[0002] Patent Document 1 discloses a rubber bushing, which is a type of vibration-damping device interposed between components that make up a vibration transmission system, and which has a structure in which an inner shaft member and an outer cylindrical member that is arranged at a distance from and extrapolated around the outer periphery of the inner shaft member are connected by a rubber elastic body interposed between them.

[0003] Furthermore, in such rubber bushings, many of them have recesses formed in the rubber elastic body in the axial direction for the purpose of adjusting the spring characteristics, for example, to make the spring characteristics different in different radial directions or to adjust the spring characteristics in the prying direction, etc. Furthermore, such recesses are generally formed in a predetermined length in the circumferential direction of the rubber elastic body.

[0004] However, in conventional rubber bushings with such recesses, there were restrictions on the ratio of the spring constant in the recess direction to the spring constant in the solid direction, and at the same time, durability was also required to be satisfactory. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3680575 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the circumstances described above, and the problem to be solved by this invention is to provide a suspension bushing with a novel structure that allows for highly accurate tuning of the ratio of the spring constant in the outboard direction to the spring constant in the solid direction, without causing a decrease in durability. [Means for solving the problem]

[0007] A first aspect of the present invention is a bearing assembly including an inner shaft member, an outer cylindrical member disposed radially outward of the inner shaft member, and a rubber elastic body connecting the inner shaft member and the outer cylindrical member. ,of The rubber elastic bodies are disposed opposite each other across the inner shaft member in a first radial direction, Material and a pair of non-through holes arranged opposite each other in a second radial direction perpendicular to the first radial direction, the pair of holes extending from both end faces in the axial direction to an intermediate region in the axial direction, the pair of non-through holes being formed in an arc shape that convex outward in the second radial direction, wherein the hole diameter in the second radial direction of the pair of non-through holes is set smaller than the hole diameter in the first radial direction of the pair of hollow portions, and each of the pair of non-through holes is arranged on the outer cylindrical member side.

[0008] In a suspension bushing constructed according to this embodiment, a pair of arc-shaped non-through holes are formed that are convex outward in a second radial direction perpendicular to the first radial direction. For example, by arbitrarily changing the shape (hole diameter and depth) of the non-through holes, it is possible to tune the spring constant ratio between the first radial direction (outer diameter direction) and the second radial direction (solid direction) with high precision. Furthermore, by making the diameter of the non-through holes smaller than the diameter of the hollow portion, it is possible to reduce the spring constant in the second radial direction (solid direction) while maintaining a low spring constant in the first radial direction (outer diameter direction), thereby satisfying the required vehicle performance. Furthermore, by forming the non-through holes in an arc shape, it is possible to reduce the stress generated in the non-through holes when a torsional input is applied, thereby preventing a decrease in durability.

[0009] In addition, because the non-through holes can be set on the outer cylindrical member side, which has a large rubber volume, it is possible to efficiently lower the spring constant in the second radial direction (solid direction) while maintaining the spring constant in the first radial direction (outer diameter direction). Furthermore, when an input is applied in the first radial direction (outer diameter direction) or torsional direction, because the non-through holes are positioned on the outer cylindrical member side, which has a long circumferential length, it is possible to reduce the stress generated in the non-through holes and prevent a decrease in durability.

[0010] A second aspect of the present invention is a suspension bushing according to the first aspect, wherein, when viewed from the axial direction, the outer peripheral shape of the inner shaft member is circular, and when viewed from the axial direction, the outer peripheral circle of the inner shaft member and a first inscribed circle defined as a circle tangent to each of the inner edges of the pair of non-through holes are concentric circles.

[0011] In the suspension bushing of this aspect, the non-through holes can be efficiently positioned on the outer cylindrical member side, which has a larger rubber volume, so that the spring constant in the second radial direction (solid direction) can be efficiently reduced while maintaining the spring constant in the first radial direction (outer cylindrical direction).When an input is applied in the first radial direction (outer cylindrical direction) or torsional direction, the entire non-through holes are positioned on the outer cylindrical member side, which has a longer circumferential length, so that the stress generated in the non-through holes can be further reduced, and a decrease in durability can be further prevented.

[0012] The third aspect of the present invention is the above Record number In a suspension bushing according to a second aspect, the pair of hollow portions are formed in an arc shape that is convex outward in the first radial direction. ,before When viewed from the axial direction, the first inscribed circle and a second inscribed circle defined as a circle tangent to each of the inner edges of the pair of hollow portions are concentric circles.

[0013] In the suspension bushing of this embodiment, hollow portions are arranged in the first radial direction (outline direction) and blind holes are arranged in the second radial direction (solid direction), which allows for efficient use of the circumferential space of the rubber elastic body. Furthermore, when an input is applied in the first radial direction (outline direction) or torsional direction, the stress generated in the hollow portions as well as the blind holes can be reduced, thereby ensuring sufficient durability of the hollow portions.

[0014] A fourth aspect of the present invention is a suspension bushing according to any one of the first to third aspects, wherein the inner shaft member extends from both end faces of the rubber elastic body in the axial direction by different lengths, and the rubber elastic body has, at one end face in the axial direction, a non-through hole in at least one of the pair of non-through holes. Kan The through hole has a projection formed in the opposing area between the inner edge and the inner shaft member.

[0015] In the suspension bushing of this aspect, the protrusion is disposed on the inner shaft member side and the blind hole is disposed on the outer cylindrical member side, so that the radial space of the rubber elastic body can be used efficiently. Furthermore, since the protrusion acts as an identification protrusion when assembling the bushing to a vehicle, Even if the lengths of the inner shaft member are different on both sides in the axial direction, incorrect assembly can be advantageously prevented.

[0016] A fifth aspect of the present invention is a suspension bush according to the fourth aspect, wherein the protrusion is formed at a position away from a dividing line that divides the inner shaft member into two in the second radial direction, on one side of the first radial direction.

[0017] In the suspension bushing of this aspect, the protrusion is spaced apart from the dividing line of the inner shaft member to one side in the first radial direction, so that the effect of the protrusion on durability can be reduced. [Effects of the Invention]

[0018] In a suspension bushing constructed according to the present invention, a pair of arc-shaped non-through holes are formed that convex outward in a second radial direction perpendicular to the first radial direction. For example, by arbitrarily changing the shape (hole diameter and depth) of the non-through holes, it is possible to precisely tune the spring constant ratio between the first radial direction (outline direction) and the second radial direction (solid direction). Furthermore, by making the diameter of the non-through holes smaller than the diameter of the hollow portion, it is possible to reduce the spring constant in the second radial direction (solid direction) while maintaining a low spring constant in the first radial direction (outline direction), thereby satisfying the required vehicle performance. Furthermore, by forming the non-through holes in an arc shape, it is possible to reduce the stress generated in the non-through holes when a torsional input is applied, thereby preventing a decrease in durability.

[0019] In addition, because the non-through holes can be set on the outer cylindrical member side, which has a large rubber volume, it is possible to efficiently lower the spring constant in the second radial direction (solid direction) while maintaining the spring constant in the first radial direction (outer diameter direction). Furthermore, when an input is applied in the first radial direction (outer diameter direction) or torsional direction, because the non-through holes are positioned on the outer cylindrical member side, which has a long circumferential length, it is possible to reduce the stress generated in the non-through holes and prevent a decrease in durability. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a plan view showing a suspension bushing according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view of the suspension bush taken along line II in FIG. 1. FIG. [Figure 3] FIG. 2 is a perspective view of FIG. 1 showing a suspension bushing. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] 1 to 3 show an automotive suspension bushing 10 as one embodiment of the present invention. This bushing 10 has an inner tubular member 12 as an inner shaft member and an outer tubular member 14 as an outer tubular member, which are elastically connected by a rubber elastic body 16, and has a generally cylindrical shape as a whole. The inner tubular member 12 of this bushing 10 is attached to the body frame of the automobile, while the outer tubular member 14 is attached to the suspension arm, so that the bushing 10 is attached to the mounting location of the suspension arm relative to the body frame and elastically connects the suspension arm to the body frame.

[0023] More specifically, the inner cylindrical member 12 is formed from a rigid material such as a metal material like steel, and has a thick, straight cylindrical shape.

[0024] An outer cylindrical member 14 is disposed on the outer peripheral surface of the inner cylindrical member 12, spaced apart radially outward. Like the inner cylindrical member 12, the outer cylindrical member 14 is formed of a rigid material such as a metal material like steel, and has a straight, cylindrical shape. The inner cylindrical member 12 and the outer cylindrical member 14 are disposed approximately coaxially with each other. The outer cylindrical member 14 is thinner than the inner cylindrical member 12 and has a shorter axial length. The outer peripheral surfaces of the corners at the open ends on both axial sides of the outer cylindrical member 14 are tapered, with the diameter decreasing axially outward.

[0025] The outer cylindrical fitting 14 is disposed externally relative to the inner cylindrical fitting 12, and the two are positioned on the same central axis. The outer cylindrical fitting 14 is disposed at the axial middle of the inner cylindrical fitting 12 so as to cover the outer peripheral surface of the axially middle portion of the inner cylindrical fitting 12. As a result, a circular annular region extending continuously in the circumferential direction and of a substantially constant size is formed between the radially opposing surfaces of the inner cylindrical fitting 12 and the outer cylindrical fitting 14. In particular, in this embodiment, the inner diameter dimension of the outer cylindrical fitting 14 is set to approximately twice the outer diameter dimension of the inner cylindrical fitting 12, so that this circular annular region is formed with a sufficient width dimension in the radial direction.

[0026] A rubber elastic body 16 is interposed in the annular region formed between the radially opposing surfaces of the inner tubular fitting 12 and the outer tubular fitting 14, and the inner tubular fitting 12 and the outer tubular fitting 14 are elastically connected by the rubber elastic body 16. The rubber elastic body 16 has a generally thick-walled cylindrical shape, and its inner peripheral surface is bonded to the outer peripheral surface of the inner tubular fitting 12, while its outer peripheral surface is bonded to the inner peripheral surface of the outer tubular fitting 14. This rubber elastic body 16 can be advantageously formed as an integrally vulcanization-molded product in which the rubber elastic body 16 is vulcanization-bonded to the inner tubular fitting 12 and the outer tubular fitting 14 by setting the inner tubular fitting 12 and the outer tubular fitting 14, which have been subjected to adhesive treatment or the like as necessary, in a vulcanization-molding mold for the rubber elastic body 16, filling the gap between the inner tubular fitting 12 and the outer tubular fitting 14 with rubber material, and then vulcanizing the resulting product.

[0027] Furthermore, if necessary, the outer tubular member 14 of the integrally vulcanization molded product obtained in this manner is subjected to diameter reduction processing such as eight-way drawing, thereby obtaining the desired bushing 10 as shown in Figures 1 to 3.

[0028] Here, the axial dimension of the rubber elastic body 16 of the bushing gradually decreases from the inner peripheral side to the outer peripheral side, and its inner peripheral surface is bonded to the outer peripheral surface of the inner tubular fitting 12, while its outer peripheral surface is bonded to substantially the entire inner peripheral surface of the outer tubular fitting 14. In other words, both axial end faces 22, 22 of the rubber elastic body 16 have substantially tapered cylindrical surfaces that protrude axially outward from the outer tubular fitting 14 toward the inner tubular fitting 12. Furthermore, the points at which the axial dimension of the rubber elastic body 16 is smallest are located near the outer tubular fitting 14 at both axial end faces 22, 22.

[0029] The rubber elastic body 16 is also formed with a pair of hollow portions 24, 24 that extend axially through it. Each hollow portion 24 is shaped to extend circumferentially for a length of approximately one-quarter of the circumference in an approximately radially central portion of the rubber elastic body 16, and is positioned opposite each other in a first radial direction (the up-and-down direction in FIG. 1 ), sandwiching the inner tubular fitting 12. In particular, in this embodiment, the hollow portions 24 have a radial width dimension that spans approximately the entire radial thickness of the rubber elastic body 16 at both circumferential end portions. Furthermore, the hollow portions 24 are formed in a circumferentially central portion thereof with an inner circumferential side stopper rubber 26 that is bonded to the inner tubular fitting 12 and protrudes radially outward from the inner tubular fitting 12 side, and an outer circumferential side stopper rubber 28 that is bonded to the outer tubular fitting 14 and protrudes radially inward from the outer tubular fitting 14 side. The protruding tip surfaces of the inner peripheral side stopper rubber 26 and the outer peripheral side stopper rubber 28 are positioned opposite to each other at a predetermined distance in the radial direction, with the hollow portion 24 sandwiched therebetween.

[0030] These stopper rubbers 26, 28 protrude into the hollow portions 24, giving the hollow portions 24 a generally H-shaped cross-section as a whole, as shown in Fig. 1. In other words, the radial width dimension (hole diameter) of each hollow portion 24 varies circumferentially, being smaller in the circumferential center portion and larger at both circumferential ends. Furthermore, because both circumferential ends of the hollow portions 24 are formed with a radial width dimension (hole diameter) that spans substantially the entire area between the radially opposing surfaces of the inner tubular metal member 12 and the outer tubular metal member 14, the rubber elastic body 16 is essentially divided in the circumferential direction by the pair of hollow portions 24, 24, and the inner tubular metal member 12 and the outer tubular metal member 14 are mutually connected only in the portions where the pair of hollow portions 24, 24 are not formed, i.e., by the pair of elastic connecting portions 34, 34 positioned opposite each other in a second radial direction perpendicular to the opposing direction of the hollow portions 24, 24. At both circumferential ends of the hollow portion 24, the stopper rubbers 26, 28 are connected and integrated with the elastic connecting portions 34, 34 that are adjacent to each other in the circumferential direction via rubber wrapping portions 30, 30 formed with a slight thickness on the surfaces of the inner tubular metal fitting 12 and the outer tubular metal fitting 14.

[0031] The outer circumferential stopper rubber 28 has a protruding tip surface that is inclined downward from the axial center toward both sides in the axial direction, and as a whole has a generally mountain-shaped cross section in which the protruding height is greatest at the axial center in the axial cross section as shown in Fig. 2. On the other hand, the inner circumferential stopper rubber 26 has a generally constant protruding height over the entire length.

[0032] Furthermore, the elastic connecting portions 34, 34 formed by the rubber elastic body 16 each have a length of approximately one-quarter of the circumference in the circumferential direction, and both circumferential side portions of each elastic connecting portion 34 are configured as thickness-changing portions over a predetermined circumferential length, with the axial thickness gradually decreasing toward the hollow portion 24. In other words, both axial end surfaces of the circumferential side portions of the elastic connecting portion 34 are configured as inclined surfaces 36, 36 that gradually incline axially inward toward the hollow portion 24 in the circumferential direction.

[0033] The rubber elastic body 16 is also formed with a pair of non-through holes 38, 38, 38, 38 that are arranged opposite each other in a second radial direction (solid direction) perpendicular to the first radial direction (outer diameter direction) and extend from each of the axial end faces 22, 22 to an intermediate region in the axial direction. Each non-through hole 38 is formed in a pair with an arc-shaped cross section that convex outward in the second radial direction, sandwiching the inner tubular metal member 12 therebetween. Each non-through hole 38 is shaped to extend circumferentially for approximately 1 / 8 of the circumference of the radially outer portion (the outer tubular metal member 14 side) of the rubber elastic body 16, and is positioned opposite each other in one radial direction (the left-right direction in FIG. 1 ) with the inner tubular metal member 12 sandwiched between them. At the intermediate region in the circumferential direction, the non-through holes 38 extend circumferentially with a constant radial width (hole diameter) that is approximately 1 / 4 of the radial thickness of the rubber elastic body 16. The circumferential end portions 40, 40 of each non-through hole 38 are curved surfaces with a gradually decreasing radial width dimension (hole diameter). Each non-through hole 38 extends axially inward from each of the axial end faces 22, 22 with a constant radial width dimension (hole diameter), and the bottoms 42, 42 are curved surfaces with a gradually decreasing radial width dimension (hole diameter). The space between the bottoms 42 of the non-through holes 38 that face each other in the axial direction forms an elastic connecting portion 34 that connects the inner tubular fitting 12 and the outer tubular fitting 14. The radial width dimension (hole diameter) of the circumferential intermediate portion of each non-through hole 38 is approximately half the radial width dimension (hole diameter) of the circumferential intermediate portion of each hollow portion 24.

[0034] On the inner tubular fitting 12 side of each non-through hole 38, there is formed an inner rubber 44 that is adhered to the inner tubular fitting 12 and protrudes radially outward from the inner tubular fitting 12 side, and an outer rubber 46 that is adhered to the outer tubular fitting 14 and protrudes radially inward from the outer tubular fitting 14 side. The protruding tip surfaces of the inner rubber 44 and outer rubber 46 are positioned opposite each other at a predetermined distance in the radial direction, with each non-through hole 38 sandwiched between them.

[0035] Although not explicitly shown in the drawings, the bushing 10 constructed as described above is, for example, installed at the attachment site of the suspension arm to the body frame with the central axis extending approximately vertically by inserting a rod fixed to the body frame of the automobile into the inner hole of the inner tubular metal fitting 12, while the outer tubular metal fitting 14 is press-fitted into an arm eye formed on a suspension arm such as an L-shaped arm or trailing arm of the automobile.

[0036] Here, in such a bushing 10, a pair of hollow portions 24, 24 is provided to set a large radial spring ratio, and a spring characteristic is exhibited that is soft in the first radial direction in which the hollow portions 24, 24 are positioned opposite each other, and hard in the second radial direction perpendicular thereto.

[0037] As shown in Figures 1 and 2, a pair of arc-shaped non-through holes 38, 38 extending in the axial direction between the inner tubular fitting 12 and the outer tubular fitting 14 are formed on both sides of the inner tubular fitting 12 in the second radial direction perpendicular to the opposing direction of the pair of hollow portions 24, 24 described above.

[0038] By forming a pair of arc-shaped non-through holes 38 in the second radial direction perpendicular to the opposing direction of the hollow portions 24, for example, by changing the shape (width and depth dimensions) of the non-through holes 38, it is possible to tune the spring constant ratio between the first radial direction (outline direction) and the second radial direction (solid direction) with high precision. Furthermore, by making the diameter of the non-through holes 38 smaller than the diameter of the hollow portions 24, it is possible to reduce the spring constant in the second radial direction (solid direction) while maintaining a low spring constant in the first radial direction (outline direction), thereby satisfying the required vehicle performance. Furthermore, by forming the non-through holes 38 in an arc shape, it is possible to reduce stress generated in the non-through holes 38 when a torsional input is applied, thereby preventing a decrease in durability.

[0039] In addition, because the non-through holes 38 can be set on the outer tubular member 14 side, which has a large rubber volume, it is possible to efficiently lower the spring constant in the second radial direction (solid direction) while maintaining the spring constant in the first radial direction (outer diameter direction). Furthermore, when an input is applied in the first radial direction (outer diameter direction) or torsional direction, because the non-through holes 38 are positioned on the outer tubular member 14 side, which has a long circumferential length, it is possible to reduce the stress generated in the non-through holes 38 and prevent a decrease in durability.

[0040] The outer peripheral shape of the inner tubular member 12 is circular, and when viewed in the axial direction, the outer peripheral circle of the inner tubular member 12 and a first inscribed circle, defined as a circle tangent to each of the inner edges of the pair of non-through holes 38, are concentric circles. This allows the non-through holes 38 to be efficiently positioned on the outer tubular member side, which has a larger rubber volume, and therefore the spring constant in the second radial direction (solid direction) can be efficiently reduced while maintaining the spring constant in the first radial direction (outline direction).

[0041] In this embodiment, a protrusion 48 is located on each of the pair of elastic connecting portions 34. As shown in FIGS. 1 and 2, these protrusions 28 are located at a distance from the outer peripheral surface of the inner tubular fitting 12 toward the outer tubular fitting 14, and are located on the inner tubular fitting 12 side at a predetermined distance from the non-through holes 38. The pair of protrusions 48 are formed at a distance on one side in the first radial direction from a parting line that divides the inner tubular fitting in two in the second radial direction. The outer edge of the protrusion 48 is formed at a predetermined distance from the parting line. This reduces the impact of the protrusions 48 on durability.

[0042] Furthermore, since the protrusions 48 are arranged on the inner cylindrical member 12 side and the blind holes 38 are arranged on the outer cylindrical member 14 side, the radial space of the rubber elastic body 16 can be used efficiently.

[0043] The inner tubular metal fitting 12 extends by different lengths from both axial end faces 22, 22 of the rubber elastic body 16. The length of the inner tubular metal fitting 12 from one end face 22 of the rubber elastic body 16 is short, and the length of the inner tubular metal fitting 12 from the other end face 22 of the rubber elastic body 16 is long. Furthermore, a protrusion 48 is formed on one end face 22 of the rubber elastic body 16 in the area where the inner edge of the non-through hole 38 faces the outer peripheral surface of the inner tubular metal fitting 12. The bushing 10 is assembled by axially press-fitting the outer tubular metal fitting 14 into an arm eye formed on a suspension arm. During this assembly, the length of the inner tubular metal fitting 12 is shortened on the side where the protrusion 48 is formed, so that the method of assembling the bushing 10 to the arm eye must be considered. Here, because the protrusion 48 described above functions as an identification protrusion, incorrect assembly can be prevented, for example, by assembling the rubber elastic body 16 with the axial end face 22 on which the protrusion 48 is formed facing upward on the vehicle.

[0044] Although the embodiments of the present invention have been described above, the present invention should not be construed as being limited by the specific descriptions in such embodiments, and can be implemented in various forms with various changes, modifications, improvements, etc. made based on the knowledge of those skilled in the art.

[0045] Furthermore, the shape (hole diameter and depth) of the non-through holes 38 is determined appropriately depending on the vibration-proofing performance required of the bushing 10, and is not limited in any way.

[0046] Furthermore, it is not necessary to form the inclined surfaces 36, 36 in the elastic connecting portion 34, and the rubber elastic body 16 may be formed to have a substantially constant thickness in the circumferential direction.

[0047] Furthermore, the arrangement direction of the bushing 10 is not limited, and can be appropriately set in consideration of the relative position of the hollow portion 24, etc., so that the required spring characteristics, vibration-damping performance, etc. are advantageously achieved in the input direction of the main radial load.

[0048] It is also possible to make the outer peripheral surface of the inner tubular member 12 and the inner peripheral surface of the outer tubular member 14 elliptical or the like in cross section perpendicular to the axis. In this embodiment, the inner shaft member is cylindrical like the inner tubular member 12, but of course a rod shape is also applicable.

[0049] Although not listed here, the present invention can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it goes without saying that all such embodiments are included within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0050] 10...Suspension bushing, 12...Inner cylindrical metal fitting, 14...Outer cylindrical metal fitting, 16...Rubber elastic body, 22...Axial end surface, 24...Hole portion, 26...Inner circumferential side stopper rubber, 28...Outer circumferential side stopper rubber, 30...Rubber winding portion, 32...Circumferential direction end surface, 34...Elastic connecting portion, 36...Inclined surface, 38... non-through hole, 40... circumferential end, 42... bottom, 44... inner rubber, 46... outer rubber, 48... protrusion

Claims

1. an inner shaft member; an outer cylindrical member disposed radially outward of the inner shaft member; a rubber elastic body connecting the inner shaft member and the outer cylindrical member; Equipped with The rubber elastic body is a pair of hollow portions disposed opposite to each other across the inner shaft member in a first radial direction and penetrating the inner shaft member in an axial direction; a pair of blind holes that are arranged opposite to each other in a second radial direction perpendicular to the first radial direction, extend from both end surfaces in the axial direction to an intermediate region in the axial direction, and are formed in an arc shape that convex outward in the second radial direction; and a hole diameter in the second radial direction of the pair of non-through holes is set to be smaller than a hole diameter in the first radial direction of the pair of hollow portions, Each of the pair of non-through holes is disposed on the outer cylindrical member side. Suspension bushing.

2. When viewed from the axial direction, the outer peripheral shape of the inner shaft member is circular, 2. The suspension bushing according to claim 1, wherein, when viewed from the axial direction, an outer circumferential circle of the inner shaft member and a first inscribed circle defined as a circle tangent to each of the inner edges of the pair of non-through holes are concentric circles.

3. The pair of recessed portions are formed on an arc that is convex outward in the first radial direction, 3. The suspension bushing according to claim 2, wherein, when viewed from the axial direction, the first inscribed circle and a second inscribed circle defined as a circle tangent to each of the inner edges of the pair of hollow portions are concentric circles.

4. the inner shaft member extends by different lengths from both end surfaces of the rubber elastic body in the axial direction, A suspension bushing as described in any one of claims 1 to 3, wherein the rubber elastic body has a protrusion formed on one end face in the axial direction in an area facing the inner edge of at least one of the pair of non-through holes and the inner shaft member.

5. A suspension bush as described in Claim 4, wherein the protrusion is formed at a position away from one side of the first radial direction relative to a dividing line that divides the inner shaft member into two in the second radial direction.

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