Bush

Abstract

To provide a bush capable of improving a static spring constant in a direction perpendicular to an axis.SOLUTION: A bottom surface 14 of a bush 10 adheres to a planar assembling surface 33. A pair of side surfaces 13 of the bush 10 adhere to a pair of holding surface parts 35 of a bracket 34 attached to the assembling surface 33. The bush 10 comprises a pair of horizontal pedestals 17 which protrude each of corner parts between a bottom surface 14 and a pair of side surfaces 13, to the outside in a nipping direction with respect to an extension line 13a of the side surface 13 in a cross section perpendicular to an axial direction of the bush 10. A static spring constant in a direction perpendicular to an axis of the bush 10 can be improved, since at least a part of the corner parts between the holding surface parts 35 and the assembling surface 33 is buried by the horizontal pedestals 17.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a bushing for vibration isolation, and more particularly to a bushing capable of improving the static spring constant in the direction perpendicular to the axis. [Background technology]

[0002] For example, a cylindrical elastic bushing is known that connects a shaft-shaped member, such as a stabilizer bar, to a bracket attached to an assembly surface of a vehicle body member. The shaft-shaped member is inserted into a retaining hole that forms the inner circumferential surface of the bushing.

[0003] The bracket includes a pair of clamping surfaces that clamp the bush in a direction perpendicular to the axis, a top surface that connects one side of the pair of clamping surfaces, and a pair of mounting portions that are provided by bending the other sides of the pair of clamping surfaces opposite the top surface portions so that they are away from each other. The pair of mounting portions are attached to a planar mounting surface in a stacked manner, so that the outer circumferential surface of the bush is in close contact with the mounting surface and the bracket. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-214287 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional technology, the outer peripheral surface of the bush is set along the clamping surface and the assembly surface, so that the corner between the clamping surface and the assembly surface is separated from the bush by bending to provide an attachment portion to the bracket. Therefore, when a load is applied to the bush in the axis-perpendicular direction and the bush elastically deforms, a part of the bush is displaced so as to escape to the corner between the clamping surface and the assembly surface, which may reduce the static spring constant of the bush in the axis-perpendicular direction.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a bushing that can improve the static spring constant in the axis-perpendicular direction by restricting the displacement of the bushing. [Means for solving the problem]

[0007] In order to achieve this object, the bushing of the present invention is made of a cylindrical elastic body whose inner circumferential surface is formed by a retaining hole into which an axial member is inserted, and comprises a bracket having a pair of clamping surface portions which clamp the bushing in the clamping direction in the direction perpendicular to the axis, a top surface portion which connects one side of the pair of clamping surface portions to each other, and a pair of mounting portions which are provided by bending the other side of the pair of clamping surface portions opposite the top surface portions outward in the clamping direction away from each other, and an outer circumferential surface which is in close contact with a planar assembly surface to which the pair of mounting portions are overlapped and attached, and comprises a bottom surface which is in close contact with the assembly surface, a pair of side surfaces which are in close contact with the pair of clamping surface portions, and a pair of lateral bases which cause the corners between the bottom surface and the pair of side surfaces to protrude outward in the clamping direction relative to the extension lines of the side surfaces in a cross section perpendicular to the axial direction of the bushing. Effect of the Invention

[0008] According to the bushing of claim 1, the bottom surface of the bushing is in close contact with the flat mounting surface, and a pair of side surfaces of the bushing are in close contact with a pair of clamping surfaces of a bracket attached to the mounting surface. The bushing has a pair of lateral pedestals that cause the corners between the bottom surface and the pair of side surfaces to protrude outward in the clamping direction with respect to the extension lines of the side surfaces in a cross section perpendicular to the axial direction of the bushing. The lateral pedestals fill at least a part of the corner between the clamping surface and the mounting surface. This makes it possible to restrict the displacement of a part of the bushing into the corners when a load is applied to the bushing in the axial direction, and to improve the static spring constant of the bush in the axial direction.

[0009] The bushing of claim 2 achieves the following effect in addition to the effect achieved by the bushing of claim 1. The corners between the clamping surface and the assembly surface are bent to provide an attachment portion to the bracket, and thus expand outward in the clamping direction as they approach the assembly surface. To match this expansion, the side pedestals increase in outward projection in the clamping direction as they approach the bottom surface. This makes it easier for the side pedestals to fill in the corners between the clamping surface and the assembly surface, and further improves the static spring constant of the bush in the axis-perpendicular direction.

[0010] The bushing of claim 3 achieves the following effect in addition to the effect achieved by the bushing of claim 1. The lateral seat is located on the bottom side of the retaining hole. This makes it possible to suppress an increase in the amount of compression of the bushing in the clamping direction between the clamping surface portion and the shaft-shaped member, which is caused by the protrusion of the lateral seat. This makes it possible to suppress an increase in the torsional spring constant of the bushing that accompanies an increase in the amount of compression, and to suppress the generation of abnormal noise that accompanies an increase in the torsional spring constant.

[0011] According to the bushing of claim 4, in addition to the effects of the bushing of any one of claims 1 to 3, the following effects are achieved. In a cross section perpendicular to the axial direction of the bushing, the surface of the clamping surface portion on the bushing side has a straight portion and a curved portion that bends from the straight portion outward in the clamping direction and connects to the mounting portion. In the cross section perpendicular to the axial direction, when the bottom surface of the bushing in a no-load state is aligned with the mounting surface, the horizontal seat is located on the bottom side of the boundary between the straight portion and the curved portion of the bracket attached to the mounting surface. This makes it possible to suppress an increase in the amount of compression of the bushing in the clamping direction between the straight portions of the pair of clamping surfaces caused by the overhang of the horizontal seat. Therefore, an increase in the torsional spring constant of the bushing that accompanies an increase in the amount of compression can be suppressed, and the generation of abnormal noise that accompanies an increase in the torsional spring constant can be suppressed.

[0012] The bushing of claim 5 achieves the following effect in addition to the effect achieved by the bushing of any one of claims 1 to 3. In a cross section perpendicular to the axial direction of the bushing, the bush-side surface of the clamping surface portion has a straight portion and a curved portion that bends from the straight portion outward in the clamping direction and connects to the mounting portion, and the back surface of the straight portion of the clamping surface portion is a straight outer surface. In a cross section perpendicular to the axial direction, the outer tip in the clamping direction of the lateral pedestal of the bushing that is in close contact with the bracket and the mounting surface is located outward in the clamping direction from the extension line of the straight outer surface, so that the lateral pedestal can more easily fill the corner between the clamping surface portion and the mounting surface, and the static spring constant of the bushing in the axial direction perpendicular to the axis can be further improved.

[0013] Furthermore, in a cross section perpendicular to the axial direction, the tip of the side base is located closer to the extension of the straight outer surface than half the distance from the boundary between the curved portion and the mounting portion to the extension of the straight outer surface, which makes it difficult for the side base to become caught between the mounting surface and the curved portion when attaching the bracket to the mounting surface. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a bushing according to one embodiment. [Diagram 2] FIG. [Diagram 3] 3 is a cross-sectional view of the bush taken along line III-III in FIG. 2. [Figure 4] 4 is a cross-sectional view of a vibration isolation unit in which a bush is assembled to a stabilizer bar, a vehicle body member, and a bracket. [Diagram 5] 5 is a cross-sectional view of the image stabilization unit taken along line VV in FIG. 4. [Figure 6] 6 is a partially enlarged cross-sectional view of the image stabilization unit, showing an enlarged portion VI of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a bush 10 in one embodiment. Fig. 2 is a front view of the bush 10. Fig. 3 is a cross-sectional view of the bush 10 taken along line III-III in Fig. 2.

[0016] Arrows U, D, L, R, F, and B in each drawing indicate the upward, downward, leftward, rightward, forward, and backward directions of the bush 10, respectively. The upward, downward, leftward, and forward directions are perpendicular to one another. Also, the bush 10 in each of Figs. 1 to 3 is shown in an unloaded state where no load other than gravity is applied. In the explanation using Figs. 1 to 3, the bush 10 in an unloaded state will be explained unless otherwise specified.

[0017] As shown in Figures 1 and 2, the bush 10 is a vibration-isolating member formed into a cylindrical shape surrounding an axis C, and is made of an elastic body such as rubber or a thermoplastic elastomer. In this specification, the direction parallel to the axis C is simply referred to as the axial direction, and the direction perpendicular to the axis C is referred to as the axis-perpendicular direction. Note that the front-to-rear direction and the axial direction of the bush 10 are the same, and the up-down direction and the left-right direction of the bush 10 are parts of the axis-perpendicular direction. The bush 10 is also formed symmetrically.

[0018] A retaining hole 11 that forms the inner peripheral surface of the bushing 10 penetrates the bushing 10 in the axial direction. This retaining hole 11 has a circular shape centered on the axis C when viewed in the axial direction (FIG. 2). The radius from the axis C to the inner peripheral surface of the retaining hole 11 is substantially constant around the entire circumference.

[0019] The outer peripheral surface of bushing 10, when viewed in the axial direction (cross section perpendicular to axis C (axial direction)), comprises a top surface 12 which is formed in a semicircular arc shape centered on axis C and forms the upper half of the outer peripheral surface, a pair of side surfaces 13 which extend parallel to each other downward from both circumferential sides of top surface 12, and a bottom surface 14 which is connected to the pair of side surfaces 13 via corners.

[0020] The bottom surface 14 is formed from a plane perpendicular to the up-down direction. The side surfaces 13 are formed perpendicular to the bottom surface 14 in a cross section perpendicular to the axis C. The outer peripheral surface of the bush 10 (top surface 12 and side surfaces 13) excluding the bottom surface 14 has a concave surface 15 formed by recessing the central portion in the axial direction inward in the direction perpendicular to the axis.

[0021] Furthermore, the axial end of the outer circumferential surface of the bushing 10 is formed by a curved surface 16 that smoothly connects to the axial end face of the bushing 10. In other words, the curved surface 16 is inclined toward the center in the axial direction as it moves away from the axial end face of the bushing 10 in the axis-perpendicular direction.

[0022] The bush 10 has a pair of lateral bases 17 that protrude outward in the left-right direction from the corners between the bottom surface 14 and the pair of side surfaces 13 in a cross section perpendicular to the axis C. The lateral bases 17 also have a concave surface 15 and a curved surface 16 formed thereon.

[0023] The horizontal pedestal 17 is located closer to the bottom surface 14 than the retaining hole 11. A boundary 18 between the side surface 13 and the horizontal pedestal 17 is a straight line perpendicular to the up-down direction when viewed from a direction perpendicular to the side surface 13. The amount of outward projection of the horizontal pedestal 17 in the left-right direction increases as it moves from the boundary 18 toward the bottom surface 14. In a cross section perpendicular to the axis C, the outer circumferential surface of the horizontal pedestal 17 slopes linearly from the boundary 18 toward the bottom surface 14, with the lower end of the slope connected to the bottom surface 14 by a smooth curve.

[0024] 1 and 3, the axial end faces of the bushing 10 are formed by a flat surface 21 perpendicular to the axis C, and a first seat 22 and a second seat 23 that are inclined outward in the axial direction as they move away from the flat surface 21 and the retaining hole 11. In the bushing 10 of this embodiment, both end faces in the axial direction are formed to be identical to each other.

[0025] The flat surfaces 21 are provided on both left and right sides of the retaining hole 11. The first seat 22 is provided at a position below the retaining hole 11. The second seat 23 is provided at a position above the retaining hole 11. Note that in Fig. 3, an extension line 21a extending the flat surfaces 21 to both sides in the up and down direction of the retaining hole 11 is shown by a two-dot chain line. The first seat 22 and the second seat 23 are located axially outboard of the extension line 21a.

[0026] The first seat 22 is inclined outward in the axial direction as it extends downward to the curved surface 16 on the outer circumferential surface of the bushing 10. The second seat 23 is inclined outward in the axial direction as it extends upward to the curved surface 16. The second seat 23 protrudes more in the axial direction than the first seat 22.

[0027] 2, a boundary 24 between the flat surface 21 and the first seat 22 is a straight line perpendicular to the up-down direction when viewed in the axial direction, and is located below the retaining hole 11. A boundary 25 between the flat surface 21 and the second seat 23 is a straight line perpendicular to the up-down direction when viewed in the axial direction, and is located below the upper end of the retaining hole 11 and above the axis C.

[0028] The first seat 22 and the second seat 23 are formed over the entire left-right length of the axial end face of the bush 10. Furthermore, the first seat 22 and the second seat 23 are formed so that the cross-sectional shape perpendicular to the left-right direction is the same over the entire left-right length, except for the portion where the retaining hole 11 is formed. This makes it easier to mold the bush 10 using a die that splits in the center in the left-right direction.

[0029] Furthermore, the position obtained by extending boundary 24, which is the starting point of the inclination of first pedestal 22, in the left-right direction is substantially in the same position as boundary 18, which is the starting point of lateral pedestal 17. This makes it easier to mold bushing 10 having first pedestal 22 and lateral pedestal 17, compared to when these are misaligned.

[0030] Next, an explanation will be given of the vibration isolation unit 30 including the bush 10 with reference to Fig. 4 to Fig. 6. Fig. 4 is a cross-sectional view of the vibration isolation unit 30 in which the bush 10 is assembled to a stabilizer bar 31 (shaft-shaped member), a vehicle body member 32, and a bracket 34. Fig. 5 is a cross-sectional view of the vibration isolation unit 30 taken along line VV in Fig. 4. Fig. 6 is a partially enlarged cross-sectional view of the vibration isolation unit 30 showing an enlarged portion VI in Fig. 5.

[0031] In this embodiment, the up-down, left-right and front-rear directions of the vibration isolation unit 30 (bush 10) respectively correspond to the up-down, left-right and front-rear directions of the vehicle on which the vibration isolation unit 30 is mounted. However, each of these directions of the vibration isolation unit 30 may be different from each direction of the vehicle. Also, the vibration isolation unit 30 is formed symmetrically.

[0032] The stabilizer bar 31 is a member for suppressing the rolling of the vehicle body, and is arranged along the left-right direction of the vehicle. The stabilizer bar 31 is a shaft-shaped steel material with a circular cross section. The stabilizer bar 31 is inserted and fitted into the retaining hole 11 of the bush 10, and the outer peripheral surface of the stabilizer bar 31 and the inner peripheral surface of the bush 10 (retaining hole 11) are in close contact with each other.

[0033] The vibration isolation unit 30 is for elastically supporting the stabilizer bar 31 on the vehicle body, and includes the above-mentioned bush 10, an assembly surface 33 of a vehicle body member 32, and a bracket 34. The vehicle body member 32 is a flat plate member with a planar assembly surface 33, and is formed from metal or synthetic resin. The vehicle body member 32 is fixed so that the back surface of the assembly surface 33 is overlapped on the vehicle body. The bottom surface 14 of the bush 10 is in close contact with the assembly surface 33 without being bonded. The vehicle body member 32 may be omitted, and the assembly surface 33 may be formed by a part of the vehicle body.

[0034] The bracket 34 is a member for assembling the bush 10, into which the stabilizer bar 31 is inserted, to the vehicle body while compressing the bush 10 between the mounting surface 33 in the axis-perpendicular direction, and is made of metal or synthetic resin. The bracket 34 includes a pair of clamping surfaces 35 for clamping the bush 10 in the left-right direction (clamping direction), a top surface 36 connecting the upper sides of the pair of clamping surfaces 35 to each other, and a pair of mounting portions 37 provided by bending the lower sides of the pair of clamping surfaces 35 outward in the left-right direction away from each other. The bracket 34 is formed by bending a single plate material, so that the clamping surfaces 35, the top surface 36, and the mounting portions 37 are integrally formed.

[0035] Top surface portion 36 is a portion that is in close contact with top surface 12 of bushing 10 without being bonded. Both the inner and outer surfaces of top surface portion 36 are formed in an arc shape, similar to top surface 12, in a cross section perpendicular to axis C (as viewed in the axial direction). Moreover, both the inner and outer surfaces of top surface portion 36 are formed with projections and recesses along axis C so as to match the shapes of concave surface 15 and curved surface 16 of top surface 12.

[0036] The clamping surface portion 35 is a portion that is in close contact with the side surface 13 of the bushing 10 without being bonded. The inner surface of the clamping surface portion 35 on the bushing 10 side is composed of a straight line portion 35a and a curved line portion 35b that is bent outward in the left-right direction from the straight line portion 35a in a cross section perpendicular to the axis C. The pair of left and right straight line portions 35a are parallel to each other. The curved line portion 35b connects the lower end of the straight line portion 35a to the mounting portion 37.

[0037] The outer surface of the clamping surface portion 35 has a linear outer surface 35d on the back side of the linear portion 35a in a cross section perpendicular to the axis C. The linear outer surface 35d and the linear portion 35a are parallel to each other. The back side of the curved portion 35b is formed by a curve that follows the curved portion 35b in a cross section perpendicular to the axis C.

[0038] Both the inner and outer surfaces of the clamping surface portion 35 are unevenly formed along the axis C to match the shapes of the concave surface 15 and the curved surface 16 of the side surface 13. The left-right distance between the pair of straight line portions 35a is approximately the same as the left-right dimension between the pair of side surfaces 13 of the bushing 10 in an unloaded state. Since the amount of left-right compression of the bushing 10 by the bracket 34 can be reduced, the torsional spring constant of the bushing 10 can be reduced. If this torsional spring constant becomes excessive, abnormal noise is likely to occur when a load is applied to the bushing 10, but by reducing the torsional spring constant, the abnormal noise can be made less likely to occur.

[0039] The mounting portion 37 is attached to the assembly surface 33 by being overlapped on the assembly surface 33 and fastened to the vehicle body with bolts 38 that vertically penetrate the mounting portion 37 and the vehicle body member 32. In the assembled state in which the mounting portion 37 is attached to the assembly surface 33, the bushing 10 is compressed mainly in the vertical direction between the assembly surface 33 and the top surface portion 36.

[0040] More specifically, in the assembled state, the bushing 10 is compressed mainly above and below the stabilizer bar 31, and the compressed portions expand in the axial direction relative to the no-load state. In particular, the central portion of the axial end face of the bushing 10 in the direction perpendicular to the axis, which is a portion away from the stabilizer bar 31, the assembly surface 33, and the bracket 34, tends to swell.

[0041] In a cross section including the axis C, the expansion of the bushing 10 causes a portion that bulges outward in the axial direction from the contact surfaces between the bushing 10 and the mounting surface 33 or the bracket 34, which has almost no effect on the static spring constant of the bushing 10 against compressive deformation in the direction perpendicular to the axis, but increases the volume of the bushing 10. Note that the compressive deformation of the bushing 10 refers to the bushing 10 being further compressed in the direction perpendicular to the axis due to vibration input to the vibration-proof unit 30, from a state in which the bushing 10 is compressed by being mounted to the stabilizer bar 31, the mounting surface 33, and the bracket 34.

[0042] In this embodiment, a first pedestal 22 and a second pedestal 23 are formed on the axial end face of the bush 10 at positions above and below the stabilizer bar 31 (retaining hole 11) and at positions that expand in the axial direction due to vertical compression. In a no-load state (the state of FIG. 3, etc.), the first pedestal 22 and the second pedestal 23 are inclined axially outward up to the mounting surface 33 and the curved surface 16 that contacts the bracket 34 as they move away from the stabilizer bar 31 in the vertical direction, respectively.

[0043] The first pedestal 22 and the second pedestal 23 can prevent the central portion of the axial end face of the bushing 10 from rising above and below the stabilizer bar 31, and can increase the contact area between the bushing 10 and the mounting surface 33 and the bracket 34. As a result, the static spring constant of the bushing 10 against compressive deformation in the vertical direction can be improved while suppressing an increase in the volume of the bushing 10.

[0044] For example, in order to prevent the bushing 10 from coming into contact with components located near the mounting surface 33 or bracket 34, it may be required that the bushing 10 not protrude in the axial direction from the mounting surface 33 or bracket 34 even when the bushing 10 is compressed and deformed to its maximum in the vertical direction. Even if it is difficult to increase the volume of the bushing 10 to achieve such a requirement, the first pedestal 22 and the second pedestal 23 can improve the static spring constant of the bushing 10 in the vertical direction.

[0045] The first seat 22 and the second seat 23 are formed on both axial end faces of the bush 10. Therefore, the static spring constant in the vertical direction of the bush 10 can be improved more than in a case where the first seat 22 and the second seat 23 are formed on only one axial end face.

[0046] In addition, the outer peripheral surface of the bushing 10 is not bonded to the mounting surface 33 and the bracket 34. Therefore, the bushing 10, which is compressed and deformed in the direction perpendicular to the axis, may slide in the axial direction relative to the mounting surface 33 and the bracket 34 while expanding in the axial direction so as to escape.

[0047] However, the bushing 10 in this embodiment can receive the vertical load from the stabilizer bar 31 by the first pedestal 22 and the second pedestal 23 which widen toward the contact surfaces with the mounting surface 33 and the bracket 34. Therefore, when the bushing 10 is compressed and deformed in the vertical direction, the bushing 10 is less likely to slip in the axial direction relative to the mounting surface 33 and the bracket 34. This makes it possible to reduce changes in the static spring constant of the bushing 10 caused by such slippage.

[0048] In addition, the first base 22 and the second base 23 within the area that overlaps with the retaining hole 11 when viewed in the vertical direction are likely to contribute to improving the static spring constant of the bush 10 in the vertical direction, while the first base 22 and the second base 23 outside that area are unlikely to contribute.

[0049] However, the first pedestal 22 and the second pedestal 23 outside the above-mentioned region can exert an effect of making it difficult for the bushing 10 to slip in the axial direction relative to the assembly surface 33 and the bracket 34. Therefore, by providing the first pedestal 22 and the second pedestal 23 not only inside the above-mentioned region but also outside the above-mentioned region, it is possible to widen the range within which the bushing 10 does not easily slip in the axial direction relative to the assembly surface 33 and the bracket 34 when the bushing 10 is compressively deformed in the vertical direction.

[0050] Furthermore, the first seat 22 and the second seat 23 are formed on the axial end face of the bushing 10 over the entire length in the left-right direction. Therefore, when the bushing 10 is compressed and deformed in the up-down direction, the bushing 10 is less likely to slip in the axial direction relative to the mounting surface 33 and the bracket 34 over the entire length in the left-right direction. This further reduces changes in the static spring constant of the bushing 10 caused by such slippage.

[0051] Below the stabilizer bar 31, the bushing 10 compressed in the vertical direction between the stabilizer bar 31 and the mounting surface 33 expands mainly in the axial direction along the flat mounting surface 33. In contrast to this, above the stabilizer bar 31, the bushing 10 compressed in the vertical direction between the stabilizer bar 31 and the bracket 34 expands not only in the axial direction but also in directions perpendicular to the axis so as to fit closely with the uneven shape of the inner surface of the bracket 34.

[0052] Therefore, when the bushing 10 is changed from an unloaded state to an assembled state, the change in the amount of axial projection from the flat surface 21 is greater in the lower first pedestal 22 than in the upper second pedestal 23. However, in the unloaded state, the maximum amount of axial projection from the flat surface 21 is set to be greater in a part of the second pedestal 23 than in the first pedestal 22. Therefore, in the assembled state, the maximum amount of projection can be made close to the same in the first pedestal 22 and the second pedestal 23. As a result, the static spring constant in the downward direction and the static spring constant in the upward direction of the bushing 10 can be made close to each other, and the static spring constants in the vertical direction can be well balanced.

[0053] In the assembled state, due to the bending (curved portion 35b) for providing the mounting portion 37 to the bracket 34, the corners between the clamping surface 35 and the assembly surface 33 expand outward in the left-right direction from the extension line 13a of the clamping surface 35 as they approach the assembly surface 33. This creates a gap S between the corner formed by the side surface 13 and bottom surface 14 of the bushing 10 and the corner formed by the clamping surface 35 and the assembly surface 33.

[0054] When a load is applied to bushing 10 in the axis-perpendicular direction and bushing 10 elastically deforms, part of bushing 10 is displaced into this gap S, which may reduce the static spring constant of bushing 10 in the axis-perpendicular direction. Furthermore, if the compression rate of bushing 10 in the axis-perpendicular direction in the assembled state is increased or the hardness of the elastic body constituting bushing 10 is increased in order to ensure this static spring constant, bushing 10 will become more susceptible to settling and its durability will be reduced.

[0055] In contrast, the bushing 10 of this embodiment is provided with a horizontal pedestal 17 that causes the corner formed by the side surface 13 and the bottom surface 14 to protrude outward in the left-right direction (towards the gap S), so that a part of the gap S can be filled with the horizontal pedestal 17. This makes it possible to restrict displacement of a part of the bushing 10 that escapes into the gap S when a load is applied to the bushing 10 in the axis-perpendicular direction, thereby improving the static spring constant of the bushing 10 in the axis-perpendicular direction. Furthermore, it is possible to eliminate the need to increase the compression rate of the bushing 10 or the hardness of the elastic body in order to improve the static spring constant, so that sagging of the bushing 10 can be suppressed and durability can be ensured.

[0056] The horizontal base 17 protrudes outward in the left-right direction more from the boundary 18 with the side surface 13 toward the bottom surface 14. This matches the expansion of the gap S (the corner between the clamping surface 35 and the mounting surface 33), making it easier to fill the gap S with the horizontal base 17 and further improving the static spring constant of the bush 10 in the axis-perpendicular direction. In addition, due to the similarity of their shapes, when attaching the bracket 34 to the mounting surface 33, it is difficult for the horizontal base 17 to get caught between the mounting surface 33 and the curved portion 35b of the bracket 34.

[0057] Since the horizontal pedestal 17 is located closer to the bottom surface 14 than the retaining hole 11, it is possible to suppress an increase in the left-right compression amount of the bushing 10 between the clamping surface portion 35 and the stabilizer bar 31, which is caused by the overhang of the horizontal pedestal 17. Therefore, it is possible to suppress an increase in the torsional spring constant of the bushing 10 that accompanies this increase, and to suppress the generation of abnormal noise that accompanies the increase in the torsional spring constant. In addition to this effect, it is possible to suppress an increase in the load when the bushing 10 with the stabilizer bar 31 inserted is inserted into the bracket 34, and it is possible to improve the work efficiency when the bushing 10 is brought into the assembled state.

[0058] 6, the horizontal base 17 in an unloaded state is shown by a two-dot chain line in a cross section perpendicular to the axis C, in which the bottom surface 14 and the side surface 13 of the bush 10 in an unloaded state are aligned with the mounting surface 33 and the straight portion 35a, respectively. In this cross section, the horizontal base 17 (boundary 18) is located closer to the bottom surface 14 than the boundary 35c between the straight portion 35a and the curved portion 35b. This makes it possible to suppress an increase in the left-right compression amount of the bush 10 between the pair of straight portions 35a, which is caused by the protrusion of the horizontal base 17. As a result, it is possible to further suppress the generation of abnormal noise due to an increase in the torsional spring constant, and to further improve the work efficiency when the bush 10 is in an assembled state.

[0059] In particular, it is preferable that boundary 18 is located 1 mm or more closer to bottom surface 14 than boundary 35c. In this case, even when manufacturing errors in bushing 10 and bracket 34 are taken into consideration, it is possible to suppress the generation of abnormal noise due to an increase in the torsional spring constant, and to improve the work efficiency when assembling bushing 10. Furthermore, it is preferable that the vertical distance between boundary 35c and boundary 18 is 3 mm or less. This makes it easier to fill gap S with horizontal base 17.

[0060] In a cross section perpendicular to the axis C, the outer left-right ends of the lateral seats 17 of the assembled bushing 10 are positioned outboard of the extension line 35e of the linear outer surface 35d in the left-right direction. This makes it easier for the lateral seats 17 to fill the gap S, thereby improving the static spring constant of the bushing 10 in the axis-perpendicular direction.

[0061] A position that is half (L / 2) of the left-right distance L from the boundary 37a between the curved portion 35b and the mounting portion 37 to the extension line 35e of the straight outer surface 35d is defined as position A. The tip of the horizontal pedestal 17 is located on the extension line 35e side of position A. This makes it possible to prevent the horizontal pedestal 17 from getting caught between the mounting surface 33 and the curved portion 35b of the bracket 34 when the bracket 34 is attached to the mounting surface 33.

[0062] As described above, it is preferable to set the shape of the horizontal base 17 in an unloaded state so that the tip of the horizontal base 17 is located between the extension line 35e and position A in the assembled state in a cross section perpendicular to the axis C. Specifically, first, in a cross section perpendicular to the axis C, the area of ​​the interference part between the horizontal base 17 in an unloaded state and the bracket 34 is calculated in a state in which the bottom surface 14 and the side surface 13 of the bush 10 in an unloaded state are aligned with the assembly surface 33 and the straight portion 35a, respectively. The area of ​​the interference part is set (adjusted) so that the tip of the horizontal base 17 is located between the extension line 35e and position A when the horizontal base 17 is expanded from the unloaded state into the gap S by this area.

[0063] Although the present invention has been described above based on the embodiment, the present invention is not limited to the above embodiment, and it can be easily imagined that various improvements and modifications are possible within the scope of the present invention. For example, the shape of the top surface 12 and the top surface portion 36 when viewed in the axial direction is not limited to a circular arc shape, and may be a polygonal shape, etc.

[0064] In addition, the concave surfaces 15 of the top surface 12 and the side surfaces 13 may be omitted. The pair of side surfaces 13 and the straight portions 35a of the pair of clamping surface portions 35 are not limited to being parallel to each other, and the distance therebetween may be increased toward the bottom surface 14 or the mounting portion 37, for example.

[0065] In the above embodiment, the bush 10 is a stabilizer bush that connects the stabilizer bar 31 to the mounting surface 33 and the bracket 34, but this is not necessarily limited to this. For example, the stabilizer bar 31 may be replaced with an axial member attached to the vibration source side such as an engine or a motor, and the axial member may be connected to the mounting surface 33 and the bracket 34 by the bush 10. Note that an axial member may be attached to the vibration receiver side such as a vehicle body, and the mounting surface 33 and the bracket 34 may be provided on the vibration source side. The shapes of the retaining hole 11 and the outer circumferential surface may be appropriately changed according to the shape of the axial member to which the bush 10 is attached.

[0066] In the above embodiment, the case where the tip of the horizontal pedestal 17 in the assembled state is located between the extension line 35e and position A has been described, but this is not necessarily limited to this. For example, the tip of the horizontal pedestal 17 may be located inside the extension line 35e in the left-right direction, or outside the position A in the left-right direction. It is not limited to the case where the horizontal pedestal 17 fills a part of the gap S, but the horizontal pedestal 17 may fill the entire gap S.

[0067] Furthermore, the boundary 18, which is the upper end of the horizontal pedestal 17, may be located above the boundary 35c, or may be located above the lower end of the retaining hole 11. The pair of left and right horizontal pedestals 17 is not limited to being formed symmetrically, and may be formed asymmetrically.

[0068] In the above embodiment, the first seat 22 located below the retaining hole 11 is inclined outward in the axial direction as it moves downward, but this is not necessarily limited to this. The first seat 22 may be located in a first direction among the axis-perpendicular directions with respect to the retaining hole 11 and inclined outward in the axial direction as it moves toward the first direction, and the first direction is not limited to the downward direction. For example, the first direction may be an upward, rightward, or leftward direction among the axis-perpendicular directions, or may be an oblique direction relative to the up, down, left, or right directions.

[0069] The second seat 23 may be located in a second direction opposite to the first direction with respect to the retaining hole 11, and may be inclined outward in the axial direction as it approaches the second direction. For example, when the first direction is the upward direction, the second direction is the downward direction. The second seat 23 may be omitted. Also, a seat similar to the first seat 22 or the second seat 23 may be provided in a direction perpendicular to the axis, other than the first direction or the second direction, with respect to the retaining hole 11.

[0070] The positions of the boundaries 24, 25 described in the above embodiment, which are the starting points of the inclination of the first pedestal 22 and the second pedestal 23, may be translated in the direction perpendicular to the axis. Furthermore, the shape of the boundaries 24, 25 is not limited to a straight line perpendicular to the up-down direction (first direction or second direction) when viewed in the axial direction. For example, the shape of the boundaries 24, 25 may be a straight line or a curved line inclined relative to the up-down direction, or may be formed by a combination of straight lines and curved lines.

[0071] In the above embodiment, the cross-sectional shape of the first seat 22 and the second seat 23 is the same over the entire length in the left-right direction, but this is not necessarily limited to this. For example, the first seat 22 and the second seat 23 may be axially expanded at the center with respect to both ends in the left-right direction, or may be axially recessed at the center in the left-right direction. Furthermore, the first seat 22 and the second seat 23 may be provided only in a part in the left-right direction.

[0072] In the above embodiment, the two axial end faces of the bush 10 are formed to be the same, but the two end faces may be different. For example, one axial end face of the bush 10 may be a flat surface only. [Explanation of symbols]

[0073] 10. Bush 11 Retaining hole 13 Side 13a Side extension 14 Bottom 17 Horizontal pedestal 31 Stabilizer bar (shaft-shaped member) 33 Assembly surface 34 Bracket 35 Clamping surface part 35a Straight section 35b Curved section 35c Boundary between straight and curved sections 35d straight outer surface 35e Extension of straight outer surface 36 Top part 37 Mounting part 37a Boundary between curved section and mounting section

Claims

1. A cylindrical bushing made of an elastic body, the inner circumferential surface of which is formed by a retaining hole into which an axial member is inserted, the bushing having an outer circumferential surface which is in close contact with a bracket including a pair of clamping surface portions which clamp the bushing in a clamping direction in a direction perpendicular to the axis, a top surface portion which connects one side of the pair of clamping surface portions to each other, and a pair of mounting portions which are provided by bending the other sides of the pair of clamping surface portions opposite the top surface portions outward in the clamping direction away from each other, the bracket comprising: A bottom surface that is in intimate contact with the assembly surface; A pair of side surfaces in close contact with the pair of clamping surface portions; A bushing characterized in that it comprises a pair of lateral bases that cause the corners between the bottom surface and the pair of side surfaces to protrude outward in the clamping direction relative to the extension lines of the side surfaces in a cross section perpendicular to the axial direction of the bushing.

2. 2. The bush according to claim 1, wherein the horizontal base has an outward projection in the clamping direction that increases toward the bottom surface side.

3. 2. The bush according to claim 1, wherein the horizontal seat is located closer to the bottom surface than the retaining hole.

4. In a cross section perpendicular to the axial direction, a surface of the clamping surface portion facing the bushing has a straight portion and a curved portion that bends from the straight portion toward the outside in the clamping direction and is connected to the mounting portion, A bush as described in any one of claims 1 to 3, characterized in that when the bottom surface of the bush in an unloaded state is aligned with the assembly surface, the horizontal base is located on the bottom surface side of the boundary between the straight portion and the curved portion of the bracket attached to the assembly surface.

5. In a cross section perpendicular to the axial direction, a surface of the clamping surface portion facing the bushing has a straight portion and a curved portion that bends from the straight portion toward the outside in the clamping direction and is connected to the mounting portion, A back surface of the straight portion of the clamping surface portion is a straight outer surface having a straight line shape, A bush as described in any one of claims 1 to 3, characterized in that the outer tip of the horizontal base of the bush, which is in close contact with the bracket and the assembly surface, is located outward in the clamping direction from the extension line of the straight outer surface, and is located closer to the extension line of the straight outer surface than half the distance from the boundary between the curved portion and the mounting portion to the extension line of the straight outer surface.

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