Bushings and structural members

Abstract

To provide a bush for a vehicle, capable of improving yield strength of a structural member to a load in a front-back direction of a vehicle.SOLUTION: Bushes (20, 20A, 20B) include external cylinders (21, 21A, 21B), internal cylinders (22, 22A, 22B) and an elastic body (23). At the point when a distance in which the internal cylinders (22, 22A, 22B) relatively approach the external cylinders (21, 21A, 21B) from a state that the central axes of the internal cylinders (22, 22A, 22B) are matched with the central axes of the external cylinders (21, 21A, 21B) is within 60% of a movable range (R), the restriction of relative rotation of the external cylinders (21, 21A, 21B) and the internal cylinders (22, 22A, 22B) is started so that relative rotation of the internal cylinders (22, 22A, 22B) with an axis in a front-back equaling direction to the external cylinders (21, 21A, 21B) is hardly generated, compared to relative rotation of the internal cylinders (22, 22A, 22B) with an axis in a left-right equaling direction to the external cylinders (21, 21A, 21B).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This disclosure relates to bushings and structural components for automobiles. [Background technology]

[0002] Automobiles are composed of various structural members. Some of these structural members are connected to other members or parts via bushings. For example, Patent Document 1 discloses a lower arm connected to the vehicle body by front bushings and rear bushings.

[0003] In the lower arm of Patent Document 1, the rear bush is located behind the front bush. The rear bush includes an outer cylinder, an inner cylinder located inside the outer cylinder, and a rubber portion filled between the outer and inner cylinders. The rear bush is fixed to the vehicle body by a bolt inserted into the inner cylinder. In the lower arm of Patent Document 1, the portion opposite to the front and rear bushes is connected to the wheel via a ball joint. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-57019 [Overview of the project] [Problems that the invention aims to solve]

[0005] For example, when a car's wheels hit a curb or similar obstacle, a load in the longitudinal direction of the car is applied to structural members such as the lower arm. This load causes deformation in the structural members. If the structural members have insufficient strength to withstand longitudinal loads, they may buckle or even break.

[0006] The object of this disclosure is to provide a bushing for automobiles that can improve the load-bearing capacity of structural members against longitudinal loads of an automobile. [Means for solving the problem]

[0007] The automotive bushing according to this disclosure comprises an outer cylinder, an inner cylinder, and an elastic body. The inner cylinder is positioned inside the outer cylinder. The elastic body is filled between the outer cylinder and the inner cylinder. When the difference between the distance from the central axis of the outer cylinder to the inner circumferential surface of the outer cylinder and the distance from the central axis of the inner cylinder to the outer circumferential surface of the inner cylinder is defined as the relative range of motion of the outer cylinder and the inner cylinder, when the distance the inner cylinder moves relative to the outer cylinder from a state where the central axis of the inner cylinder coincides with the central axis of the outer cylinder to within 60% of the range of motion, the relative rotation of the outer cylinder and the inner cylinder is restricted so that relative rotation of the inner cylinder relative to the outer cylinder, around the front-rear direction, is less likely to occur compared to relative rotation of the inner cylinder relative to the outer cylinder around the left-right direction. The left-right direction is the direction corresponding to the left-right direction of the vehicle when the bushing is installed in the vehicle. The front-rear direction is the direction corresponding to the front-rear direction of the vehicle when the bushing is installed in the vehicle. [Effects of the Invention]

[0008] The automotive bushings described herein can improve the load-bearing capacity of structural members against longitudinal loads on an automobile. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the schematic configuration of a structural member for an automobile according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view of a bushing for an automobile according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view of the bush shown in Figure 2, taken along line III-III. [Figure 4] Figure 4 is a diagram illustrating the operation of a bush according to the first embodiment, and is a cross-sectional view of the bush. [Figure 5] Figure 5 is a diagram illustrating the operation of the bush according to the first embodiment, and is a VV cross-sectional view of the bush shown in Figure 4. [Figure 6] FIG. 6 is a diagram for explaining the operation of the bush according to the first embodiment, and is a view of the bush shown in FIGS. 4 and 5 as seen from the front of the vehicle. [Figure 7] FIG. 7 is a longitudinal sectional view of the bush according to the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view of the bush according to the second embodiment. [Figure 9] FIG. 9 is a diagram for explaining the operation of the bush according to the second embodiment, and is a longitudinal sectional view of the bush. [Figure 10] FIG. 10 is a longitudinal sectional view of the bush according to the third embodiment. [Figure 11] FIG. 11 is a cross-sectional view of the bush according to the third embodiment. [Figure 12] FIG. 12 is a diagram for explaining the operation of the bush according to the third embodiment, and is a longitudinal sectional view of the bush. [Figure 13] FIG. 13 is a load-displacement curve of the structural member obtained by analysis.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The bush for a vehicle according to the embodiment includes an outer cylinder, an inner cylinder, and an elastic body. The inner cylinder is disposed inside the outer cylinder. The elastic body is filled between the outer cylinder and the inner cylinder. When the difference between the distance from the central axis of the outer cylinder to the inner peripheral surface of the outer cylinder and the distance from the central axis of the inner cylinder to the outer peripheral surface of the inner cylinder is defined as the relative movable range of the outer cylinder and the inner cylinder, when the distance by which the inner cylinder relatively moves and approaches the outer cylinder from the state where the central axis of the inner cylinder coincides with the central axis of the outer cylinder is within 60% of the movable range, the relative rotation of the inner cylinder with respect to the outer cylinder about the front-back equivalent direction is less likely to occur compared to the relative rotation of the inner cylinder with respect to the outer cylinder about the left-right equivalent direction. Thus, the regulation of the relative rotation of the outer cylinder and the inner cylinder is started. The left-right equivalent direction is the direction corresponding to the left-right direction of the vehicle when the bush is attached to the vehicle. The front-back equivalent direction is the direction corresponding to the front-back direction of the vehicle when the bush is attached to the vehicle (first configuration).

[0011] When a load is applied to a structural member in the longitudinal direction of an automobile, in a bush that connects the structural member to another member or component, due to the load, the inner cylinder moves relatively and approaches the outer cylinder. Thereafter, the inner cylinder rotates relatively with respect to the outer cylinder, for example, about the longitudinal direction of the vehicle. This relative rotation of the outer cylinder and the inner cylinder affects the yield strength (maximum load) of the structural member.

[0012] In contrast, the bush according to the first configuration is configured to restrict the relative rotation of the inner cylinder with respect to the outer cylinder when the outer cylinder and the inner cylinder approach relatively. More specifically, before the relative movement distance between the outer cylinder and the inner cylinder exceeds 60% of the movable range, compared with the relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the left - right direction of the automobile, the relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the longitudinal direction of the automobile is less likely to occur. Thereby, deformation of the portion of the structural member to which the bush is attached is suppressed. Therefore, the yield strength of the structural member can be improved against the load in the longitudinal direction of the automobile.

[0013] In the above bush, when the relative movement distance between the outer cylinder and the inner cylinder is within 60% of the movable range, it is preferable that the restriction of the relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the longitudinal direction and the restriction of the relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the up - down direction are started. The direction corresponding to the up - down direction is the direction corresponding to the up - down direction of the automobile in the state where the bush is attached to the automobile (second configuration).

[0014] In the second configuration, before the relative movement distance between the outer cylinder and the inner cylinder exceeds 60% of the movable range, the relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the up - down direction of the automobile is also restricted. Thereby, the structural member to which the bush is attached can exhibit excellent yield strength against the load in the longitudinal direction of the automobile.

[0015] The relative rotation of the inner cylinder with respect to the outer cylinder about the direction corresponding to the longitudinal direction may be restricted by the contact of the inner cylinder with the outer cylinder (third configuration).

[0016] The inner cylinder may include a cylindrical inner cylinder body and a flange portion. The flange portion protrudes from the outer circumferential surface of the inner cylinder body toward the outer cylinder. In this case, the outer cylinder may include an opening. The opening is formed in the side wall of the outer cylinder so as to receive the flange portion when the relative movement distance between the outer cylinder and the inner cylinder is within 60% of the range of motion (fourth configuration).

[0017] In the fourth configuration, when the outer and inner cylinders are relatively close together, the flange portion provided on the inner cylinder is received by the opening provided on the outer cylinder. In this case, when the inner cylinder attempts to rotate relative to the outer cylinder about an axis corresponding to the front-rear direction, the flange portion contacts the edge of the opening, restricting the rotation. As a result, the structural member to which the bushing is attached can exhibit excellent resistance to the front-rear load of the automobile.

[0018] The inner cylinder may include multiple flange portions. The outer cylinder may include multiple openings corresponding to the multiple flange portions. The multiple flange portions may be arranged, for example, spaced apart in the axial direction of the inner cylinder (fifth configuration).

[0019] The flange portion can protrude from the outer circumferential surface of the inner cylinder body in a direction corresponding to the front-to-back direction (sixth configuration). In this case, it is preferable that the flange portion is positioned offset in a direction corresponding to the left-to-right direction with respect to the central axis of the inner cylinder (seventh configuration).

[0020] In the seventh configuration, the flange portion is positioned offset from the central axis of the inner cylinder in a direction corresponding to the left-right direction of the vehicle. In this case, the distance between the flange portion and the outer cylinder in the left-right direction is shorter compared to the case where the flange portion is positioned in a position that coincides with the central axis of the inner cylinder. As a result, when a load is applied to the structural member in the longitudinal direction of the vehicle, and the inner cylinder approaches the outer cylinder relatively in the left-right direction of the vehicle, the flange portion of the inner cylinder is more easily inserted into the opening of the outer cylinder. In other words, because the distance between the flange portion of the inner cylinder and the outer cylinder in the left-right direction is relatively short, the flange portion can be inserted into the opening even when the relative approach between the inner cylinder and the outer cylinder is small.

[0021] The flange portion can protrude from the outer circumferential surface of the inner cylinder body in a direction corresponding to the left and right. In this case, the outer cylinder may include a recess having a concave shape on the inner cylinder body side. The recess is formed in at least the portion of the side wall of the outer cylinder on the flange portion side when viewing the bush in a cross-section including the central axis of the outer cylinder (8th configuration).

[0022] In the eighth configuration, when the outer cylinder and inner cylinder are relatively close together, the flange portion provided on the inner cylinder is received by the opening provided on the outer cylinder. In this case, when the inner cylinder attempts to rotate relative to the outer cylinder about an axis corresponding to the front-rear direction, the flange portion contacts the edge of the opening, restricting the rotation. Furthermore, when the flange portion of the inner cylinder is inserted into the opening of the outer cylinder, the elastic body is strongly compressed and hardened between the flange portion of the inner cylinder body and the recess provided on the outer cylinder. In this case, when the inner cylinder attempts to rotate relative to the outer cylinder about an axis corresponding to the front-rear direction, the recess of the outer cylinder is supported by the hardened elastic body, which can suppress the rotation.

[0023] The flange portion can protrude from the outer circumferential surface of the inner cylinder body in corresponding left and right directions. In this case, the inner cylinder body may include a convex portion having a shape that is convex toward the outer cylinder side. The convex portion is formed on at least the flange portion side of the side wall of the inner cylinder body when viewing the bush in a cross-section including the central axis of the inner cylinder (9th configuration).

[0024] In the ninth configuration, when the outer cylinder and inner cylinder are relatively close together, the flange portion provided on the inner cylinder is received by the opening provided on the outer cylinder. In this case, when the inner cylinder attempts to rotate relative to the outer cylinder about an axis corresponding to the front-rear direction, the flange portion contacts the edge of the opening, restricting the rotation. Furthermore, when the flange portion of the inner cylinder is inserted into the opening of the outer cylinder, the elastic body on the flange portion side is strongly compressed and hardened by the protrusion of the inner cylinder body and the outer cylinder. In this case, when the inner cylinder attempts to rotate relative to the outer cylinder about an axis corresponding to the front-rear direction, the protrusion of the inner cylinder body is supported by the hardened elastic body, which can suppress the rotation.

[0025] The structural member for an automobile according to this embodiment comprises the bush and the member body to which the bush is attached (10th configuration).

[0026] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0027] <First Embodiment> [Structural members and bushing structure] Figure 1 is a perspective view showing the schematic configuration of a structural member 100 for an automobile according to the first embodiment. The structural member 100 is, for example, a chassis component of an automobile. Chassis components include suspension arms such as lower arms and upper arms. In this embodiment, an example in which the structural member 100 is a lower arm will be described.

[0028] Referring to Figure 1, the structural member 100 comprises a member body 10 and a bush 20.

[0029] The component body 10 is formed from a sheet material. Typically, the component body 10 is formed from a metal sheet. When the component body 10 is formed from a metal sheet, the metal sheet may be composed of, for example, iron (Fe), titanium (Ti), aluminum (Al), magnesium (Mg), or alloys thereof. The component body 10 can be manufactured, for example, by press forming of a metal sheet.

[0030] In this embodiment, the main body of the member 10 is curved overall in plan view. The main body of the member 10 includes arms 11 and 12 and a mounting portion 13. The arms 11 and 12 extend in different directions in plan view of the main body of the member 10. When the structural member 100, which is a lower arm, is attached to a vehicle, one arm 11 extends generally in the left-right direction (vehicle width direction) of the vehicle, and the other arm 12 extends generally in the front-rear direction (vehicle length direction) of the vehicle. Hereinafter, with respect to the structural member 100 including the bush 20, the directions corresponding to the left-right direction and the front-rear direction of the vehicle when the structural member 100 is attached to a vehicle will be referred to as the left-right corresponding direction and the front-rear corresponding direction, respectively. Also, the direction corresponding to the up-down direction of the vehicle when the structural member 100 is attached to a vehicle will be referred to as the up-down corresponding direction.

[0031] The tip of arm 11 is connected to the vehicle's wheel via a bush (not shown), for example, a ball joint and a steering knuckle. The boundary between arms 11 and 12 is connected to the vehicle body via a bush (not shown). The tip of arm 12 is connected to the vehicle body via a bush 20. The tip of arm 12 is provided with a mounting portion 13 for attaching the bush 20. The tip of arm 12 is positioned rearward relative to the boundary between arms 11 and 12 when the structural member 100 is attached to the vehicle.

[0032] The bush 20 includes an outer cylinder 21, an inner cylinder 22, and an elastic body 23. The outer cylinder 21 and the inner cylinder 22 are, for example, substantially cylindrical. However, the outer cylinder 21 and the inner cylinder 22 may also have cylindrical shapes other than cylindrical, such as polygonal or elliptical. The inner cylinder 22 is located inside the outer cylinder 21. The outer cylinder 21 and the inner cylinder 22 are typically made of metal. An elastic body 23 is filled between the outer cylinder 21 and the inner cylinder 22. The elastic body 23 is, for example, made of a material mainly composed of rubber.

[0033] The structure of the bush 20 and its vicinity within the structural member 100 will be described in more detail below with reference to Figures 2 and 3. Figure 2 is a cross-sectional view of the bush 20. That is, Figure 2 shows a cross-section of the bush 20 when cut by a plane perpendicular to the vertical direction. Figure 3 is a cross-sectional view of the bush 20 shown in Figure 2, taken along line III-III.

[0034] Referring to Figures 2 and 3, the bush 20 is attached to the mounting portion 13 of the member body 10. The mounting portion 13 includes a mounting hole 131 and a peripheral wall 132. The mounting hole 131 is a through hole that penetrates the member body 10 in the direction of its plate thickness. The peripheral wall 132 is provided continuously with respect to the peripheral edge of the mounting hole 131. The peripheral wall 132 extends from the peripheral edge of the mounting hole 131 to one side of the member body 10 in the direction of its plate thickness. The mounting hole 131 and the peripheral wall 132 can be formed, for example, by burring the member body 10.

[0035] The outer cylinder 21 of the bush 20 is inserted into the mounting hole 131 and the peripheral wall 132 of the member body 10. The outer cylinder 21 is press-fitted into the mounting hole 131 and the peripheral wall 132, for example. Therefore, the mounting hole 131 and the peripheral wall 132 have shapes corresponding to the outer cylinder 21. For example, if the outer cylinder 21 is cylindrical, the mounting hole 131 is circular and the peripheral wall 132 is cylindrical.

[0036] When no load is applied to the structural member 100, the inner cylinder 22 of the bush 20 is arranged coaxially with the outer cylinder 21 inserted into the mounting hole 131 and the peripheral wall 132. That is, when no load is applied to the structural member 100, the inner cylinder 22 has a common central axis A with the outer cylinder 21. In this embodiment, the inner cylinder 22 includes an inner cylinder body 221 and two flange portions 222a and 222b.

[0037] The inner cylinder body 221 is formed in a cylindrical shape having a central axis A. The inner cylinder body 221 has, for example, a cylindrical shape. Bolts (not shown) that connect the structural member 100 to other members or parts are inserted into the inner cylinder body 221.

[0038] The flange portions 222a and 222b each protrude from the outer circumferential surface of the inner cylinder body 221 toward the outer cylinder 21. Each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 in a direction corresponding to the front-rear direction. In this embodiment, when the bush 20 is attached to the automobile, each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 toward the front of the vehicle body. The flange portions 222a and 222b penetrate the elastic body 23 filled between the inner cylinder 22 and the outer cylinder 21. Notches 231a and 231b may be provided in the portions of the elastic body 23 corresponding to the flange portions 222a and 222b. The notches 231a and 231b have a concave shape toward the inner cylinder body 221 side from the outer cylinder 21 side surface of the elastic body 23, for example, so as to expose at least a portion of the flange portions 222a and 222b from the elastic body 23.

[0039] The flange portions 222a and 222b are spaced apart in the axial direction of the inner cylinder 22. Between flange portion 222a and flange portion 222b in the axial direction of the inner cylinder 22, the mounting hole 131 and the peripheral wall 132 of the member body 10 are located.

[0040] The outer cylinder 21 includes two openings 211a and 211b, corresponding to the flange portions 222a and 222b of the inner cylinder 22. One opening 211a is positioned in the axial direction of the outer cylinder 21 and inner cylinder 22 to correspond to one flange portion 222a. The other opening 211b is positioned in the axial direction of the outer cylinder 21 and inner cylinder 22 to correspond to the other flange portion 222b.

[0041] The flange portion 222a is positioned offset to the left and right with respect to the central axis A of the inner cylinder 22. Similarly, the flange portion 222b is also positioned offset to the left and right with respect to the central axis A of the inner cylinder 22. More specifically, the flange portions 222a and 222b are positioned outside the vehicle body of the automobile relative to the central axis A of the inner cylinder 22. In this embodiment, the flange portions 222a and 222b have a substantially rectangular shape in their longitudinal cross-sectional view. However, the shape of the flange portions 222a and 222b is not limited to this.

[0042] [Operation of the Bush] Next, the operation of the bush 20 when a load in the longitudinal direction of the vehicle is applied to the structural member 100 will be described with reference to FIGS. 4 to 6 in addition to FIGS. 2 and 3. FIGS. 4 to 6 are diagrams for explaining the operation of the bush included in the structural member, and all show the bush 20 and its vicinity in the structural member 100.

[0043] First, referring to FIGS. 2 and 3, in a state where no load is applied to the structural member 100, the outer cylinder 21 and the inner cylinder 22 in the bush 20 are substantially coaxially arranged. In this state, when viewed in a cross-section including the central axis A of the bush 20, the distance in the direction perpendicular to the central axis A from the outer peripheral surface of the inner cylinder 22 to the inner peripheral surface of the outer cylinder 21 is D out -D in It is. D out -D in is defined as the relative movable range R of the outer cylinder 21 and the inner cylinder 22.

[0044] D out is the distance in the direction perpendicular to the central axis A from the central axis A to the inner peripheral surface of the outer cylinder 21 in a cross-section including the central axis A of the bush 20. D in is the distance in the direction perpendicular to the central axis A from the central axis A to the outer peripheral surface of the inner cylinder main body 221 in a cross-section including the central axis A of the bush 20. D in is D out It is assumed that the measurement is made at the same position. When the outer cylinder 21 and the inner cylinder main body 221 have a cylindrical shape, D out , D in are the radius of the inner peripheral surface of the outer cylinder 21 and the radius of the outer peripheral surface of the inner cylinder main body 221, respectively.

[0045] The outer cylinder 21 is fixed to the main body 10 by, for example, press-fitting into mounting holes 131 and peripheral walls 132. On the other hand, the inner cylinder 22 is connected to a separate member or component from the structural member 100 via bolts. Therefore, for example, when a car drives onto a curb and a load is applied to the structural member 100 from the front of the vehicle, the inner cylinder 22 moves relative to the outer cylinder 21, as shown in Figures 4 and 5. The inner cylinder 22 first moves relative to the outer cylinder 21, mainly in the left-right direction, from a state where the central axes of the outer cylinder 21 and the inner cylinder 22 coincide. The distance between the outer circumferential surface of the inner cylinder body 221 and the inner circumferential surface of the outer cylinder 21 decreases as the relative approach between the outer cylinder 21 and the inner cylinder 22 progresses.

[0046] After the outer cylinder 21 and inner cylinder 22 approach each other, the inner cylinder 22 attempts to rotate relative to the outer cylinder 21, mainly around the longitudinal direction. The bush 20 is configured to begin restricting the relative rotation of the inner cylinder 22 with respect to the outer cylinder 21, around the longitudinal direction, when the distance (displacement) that the inner cylinder 22 has moved relative to the outer cylinder 21 is within 60% of the range of motion R shown in Figure 3. Furthermore, the bush 20 also begins restricting the relative rotation of the inner cylinder 22 with respect to the outer cylinder 21, around the vertical direction, when the relative distance between the outer cylinder 21 and the inner cylinder 22 is within 60% of the range of motion R. In other words, the restriction of relative rotation around the longitudinal and vertical directions begins before the radial distance between the outer surface of the inner cylinder body 221 and the inner surface of the outer cylinder 21 falls below 40% of the range of motion R. For example, when the relative travel distance of the outer cylinder 21 and the inner cylinder 22 exceeds 30% of the range of motion R, the bush 20 begins and continues to restrict the relative rotation of the outer cylinder 21 and the inner cylinder 22 around the axes corresponding to the front-rear and up-down directions.

[0047] In this embodiment, when the distance the inner cylinder 22 has moved relative to the outer cylinder 21 is 60% or less of the range of motion R (Figure 2), the openings 211a and 211b of the outer cylinder 21 receive the flange portions 222a and 222b of the inner cylinder 22, respectively. For example, the portions of the flange portions 222a and 222b that are exposed from the notches 231a and 231b of the elastic body 23 (Figures 2 and 3) are inserted into the openings 211a and 211b.

[0048] Figure 6 is a view of the bush 20 and its vicinity within the structural member 100, as seen from the front of the automobile. As shown by the dashed line in Figure 6, when the flange portion 222a of the inner cylinder 22 is positioned inside the opening 211a of the outer cylinder 21, when the inner cylinder 22 attempts to rotate relative to the outer cylinder 21 about an axis corresponding to the front-rear direction, the flange portion 222a of the inner cylinder 22 contacts the edge of the opening 211a of the outer cylinder 21. Similarly, when the flange portion 222b of the inner cylinder 22 is positioned inside the opening 211b of the outer cylinder 21, when the inner cylinder 22 attempts to rotate relative to the outer cylinder 21 about an axis corresponding to the front-rear direction, the flange portion 222b of the inner cylinder 22 contacts the edge of the opening 211b of the outer cylinder 21. The flange portions 222a and 222b contact the side edges of the openings 211a and 211b in the circumferential direction of the outer cylinder 21. This restricts the relative rotation of the outer cylinder 21 and the inner cylinder 22 with respect to the axis corresponding to the front-to-back direction.

[0049] Even when the inner cylinder 22 attempts to rotate relative to the outer cylinder 21 about an axis corresponding to the vertical direction, the flange portions 222a and 222b of the inner cylinder 22 contact the edges of the openings 211a and 211b of the outer cylinder 21. The flange portions 222a and 222b contact the side edges of the openings 211a and 211b in the circumferential direction of the outer cylinder 21. This restricts the relative rotation of the outer cylinder 21 and the inner cylinder 22 about an axis corresponding to the vertical direction.

[0050] On the other hand, even after the openings 211a and 211b of the outer cylinder 21 have received the flange portions 222a and 222b of the inner cylinder 22, a certain degree of relative rotation of the outer cylinder 21 and the inner cylinder 22 around the left-right axis is permitted. When the distance the inner cylinder 22 has moved relative to the outer cylinder 21 is within 60% of the range of motion R (Figure 3), the bush 20 begins to restrict the relative rotation of the outer cylinder 21 and the inner cylinder 22 around the front-back axis, making it less likely for the inner cylinder 22 to rotate relative to the outer cylinder 21 around the left-right axis compared with the relative rotation of the inner cylinder 22 around the outer cylinder 21 around the front-back axis.

[0051] The likelihood of relative rotation occurring around the left-right and right-back directions, and the likelihood of relative rotation occurring around the front-back direction, for the outer cylinder 21 and inner cylinder 22 can be confirmed, for example, using a known actuator. Specifically, while holding the outer cylinder 21, an actuator is connected to the inner cylinder 22, and the inner cylinder 22 is rotated by 5 degrees around the left-right direction. A torque-inner cylinder 22 rotation angle curve is obtained, and the maximum value of the slope of the curve (torque increment / rotation angle increment of the inner cylinder 22) is obtained. Similarly, using the actuator, the inner cylinder 22 is rotated by 5 degrees around the front-back direction, just as when rotating around the left-right direction, and a torque-inner cylinder 22 rotation angle curve is obtained. The maximum value of the slope of the curve is obtained. If the maximum value of the slope of the curve when rotating around the front-back direction is 100 times or more greater than the maximum value of the slope of the curve when rotating around the left-right direction, it is determined that relative rotation of the inner cylinder 22 with respect to the outer cylinder 21 around the front-back direction is less likely to occur than relative rotation of the inner cylinder 22 with respect to the outer cylinder 21 around the left-right direction.

[0052] In the bush 20 according to this embodiment, by appropriately setting the relationship between the dimensions of the openings 211a and 211b of the outer cylinder 21 and the dimensions of the flange portions 222a and 222b of the inner cylinder 22, This configuration allows for relative rotation of the outer cylinder 21 and inner cylinder 22 around the left-right axis, while suppressing relative rotation of the outer cylinder 21 and inner cylinder 22 around the front-rear axis. As a result, relative rotation of the outer cylinder 21 and inner cylinder 22 around the front-rear axis is less likely to occur compared to relative rotation of the outer cylinder 21 and inner cylinder 22 around the left-right axis. For example, in this embodiment, the length (height) of the openings 211a and 211b of the outer cylinder 21 in the vertical direction is 2.00 times greater than the length (thickness) of the flange portions 222a and 222b of the inner cylinder 22 in the vertical direction (height of openings 211a and 211b / thickness of flange portions 222a and 222b ≥ 2.00). The circumferential length (width) of the openings 211a and 211b of the outer cylinder 21 can be 1.10 times or less the circumferential length (width) of the flange portions 222a and 222b of the inner cylinder 22 (width of openings 211a and 211b / width of flange portions 222a and 222b ≤ 1.10). In this case, as shown by the dashed line in Figure 6, when the inner cylinder 22 attempts to rotate relative to the outer cylinder 21 about an axis corresponding to the front-rear direction, the flange portions 222a and 222b can immediately contact the edges of the openings 211a and 211b, thereby suppressing the rotation. However, the shape and dimensions of the openings 211a and 211b and the flange portions 222a and 222b are not limited to this. The relationship between the dimensions of the openings 211a and 211b of the outer cylinder 21 and the dimensions of the flange portions 222a and 222b of the inner cylinder 22 should be set appropriately so that relative rotation of the outer cylinder 21 and inner cylinder 22 around the front-to-back direction is less likely to occur compared to relative rotation of the outer cylinder 21 and inner cylinder 22 around the left-to-right direction.

[0053] Furthermore, when the opening 211a of the outer cylinder 21 is inserted into the flange portion 222a of the inner cylinder 22, the vertical clearance between the edge of the opening 211a and the flange portion 222a is greater than the circumferential clearance between the outer cylinder 21 and the inner cylinder 22. Similarly, when the opening 211b of the outer cylinder 21 is inserted into the flange portion 222b of the inner cylinder 22, the vertical clearance between the edge of the opening 211b and the flange portion 222b is greater than the circumferential clearance between the outer cylinder 21 and the inner cylinder 22. By ensuring sufficient clearance between the edges of the openings 211a and 211b and the flange portions 222a and 222b in the vertical direction, relative rotation of the inner cylinder 22 with respect to the outer cylinder 21, with respect to the left-right axis, becomes easier to allow. The clearance between the edges of the openings 211a and 211b and the flange portions 222a and 222b in the vertical direction can be determined by the relationship between the projected area of ​​the flange portions 222a and 222b onto the inner cylinder body 221 when relative rotation occurs between the outer cylinder 21 and the inner cylinder 22 with respect to the left-right direction, and the height of the openings 211a and 211b.

[0054] The clearance between the edges of the openings 211a and 211b in the circumferential direction of the outer cylinder 21 and inner cylinder 22 and the flange portions 222a and 222b can be determined according to the allowable relative rotation of the inner cylinder 22 with respect to the outer cylinder 21, with respect to the corresponding front-to-back and up-to-down directions. For example, the allowable relative rotation (rotation angle) of the inner cylinder 22 with respect to the outer cylinder 21 with respect to the corresponding front-to-back direction is set to 1° or less. For example, the allowable relative rotation (rotation angle) of the inner cylinder 22 with respect to the outer cylinder 21 with respect to the corresponding up-to-down direction is set to 1° or less. The clearance between the edges of the openings 211a and 211b in the circumferential direction of the outer cylinder 21 and inner cylinder 22 and the flange portions 222a and 222b is determined geometrically and uniquely according to these allowables. From the viewpoint of facilitating the insertion of flange portions 222a and 222b into the openings 211a and 211b, it is preferable that the clearance between the edges of the openings 211a and 211b and the flange portions 222a and 222b in the circumferential direction of the outer cylinder 21 and inner cylinder 22 satisfies the condition that the width of the openings 211a and 211b / the width of the flanges 222a and 222b ≥ 1.05. However, this clearance is set such that the allowable relative rotation of the outer cylinder 21 and inner cylinder 22 around the corresponding front-to-back and up-to-down directions is smaller than the allowable relative rotation of the outer cylinder 21 and inner cylinder 22 around the corresponding left-to-right direction.

[0055] [effect] When a load in the longitudinal direction of the automobile is applied to the structural member 100 according to this embodiment, the bush 20 causes the inner cylinder 22 to move relative to the outer cylinder 21 and approach it, starting from a state where the central axes of the outer cylinder 21 and the inner cylinder 22 coincide. The bush 20 begins to restrict the relative rotation of the inner cylinder 22 with respect to the outer cylinder 21, about the longitudinal direction as the axis, before the relative movement distance of the outer cylinder 21 and the inner cylinder 22 exceeds 60% of the range of motion R. More specifically, when a load is applied to the structural member 100 from the front of the vehicle body, causing the outer cylinder 21 and the inner cylinder 22 to approach each other, the flange portions 222a and 222b of the inner cylinder 22 are inserted into the openings 211a and 211b of the outer cylinder 21. As a result, when the inner cylinder 22 attempts to rotate relative to the outer cylinder 21 about the longitudinal direction as the axis, the flange portions 222a and 222b contact the edges of the openings 211a and 211b, restricting the rotation. Therefore, deformation of the part of the structural member 100 to which the bush 20 is attached becomes less likely. Thus, the load-bearing capacity of the structural member 100 against the longitudinal load of the automobile can be improved.

[0056] In the structural member 100 according to this embodiment, the flange portions 222a and 222b of the inner cylinder 22 are positioned outside the peripheral wall 132 of the mounting portion 13 provided on the member body 10 in the vertical direction. Therefore, even if the inner cylinder 22 approaches the outer cylinder 21, for example in the radial direction, the flange portions 222a and 222b do not interfere with the peripheral wall 132. Thus, it is not necessary to provide an opening in the peripheral wall 132 to receive the flange portions 222a and 222b.

[0057] In the bush 20 according to this embodiment, after a load in the longitudinal direction of the automobile is applied to the structural member 100, the outer cylinder 21 and the inner cylinder 22 can move relative to each other in the initial stages. That is, deformation of the elastic body 23 filled between the outer cylinder 21 and the inner cylinder 22 is permitted. This ensures ride comfort in an automobile to which the structural member 100 including the bush 20 is attached.

[0058] In this embodiment, the bush 20 is configured such that, when the distance the outer cylinder 21 and inner cylinder 22 have moved relative to each other is within 60% of the range of motion R, relative rotation of the inner cylinder 22 relative to the outer cylinder 21 around the longitudinal axis is less likely to occur compared to relative rotation of the inner cylinder 22 around the longitudinal axis. In other words, even after the outer cylinder 21 and inner cylinder 22 have come into relative proximity, relative rotation of the outer cylinder 21 and inner cylinder 22 around the longitudinal axis is permitted to a certain extent. This ensures the load-bearing capacity of the structural member 100 against longitudinal loads of the vehicle while ensuring the ride comfort of the vehicle to which the structural member 100 is attached.

[0059] In the bush 20 according to this embodiment, the flange portions 222a and 222b are positioned offset in the left-right direction with respect to the central axis A of the inner cylinder 22. As a result, the distance from the flange portions 222a and 222b to the outer cylinder 21 in the left-right direction is shorter compared to the case where the flange portions 222a and 222b are positioned to coincide with the central axis of the inner cylinder 22. Therefore, when a load is applied to the structural member 100 in the longitudinal direction of the automobile, and the inner cylinder 22 approaches the outer cylinder 21 relatively in the left-right direction of the automobile, the flange portions 222a and 222b are more easily inserted into the openings 211a and 211b of the outer cylinder 21. In other words, because the distance between the flange portions 222a and 222b and the outer cylinder 21 in the left-right direction is relatively short, the flange portions 222a and 222b are inserted into the openings 211a and 211b even when the relative approach between the inner cylinder 22 and the outer cylinder 21 is small.

[0060] <Second Embodiment> Figure 7 is a longitudinal cross-sectional view (cross-sectional view including the central axis A) of the bush 20A included in the structural member 100A according to the second embodiment. Figure 8 is a transverse cross-sectional view (cross-sectional view VIII-VIII) of the bush 20A. The structural member 100A according to this embodiment includes a member body 10 similar to the structural member 100 according to the first embodiment. However, the bush 20A has a different configuration from the bush 20 of the first embodiment.

[0061] Referring to Figures 7 and 8, the bush 20A according to this embodiment includes an outer cylinder 21A and an inner cylinder 22A.

[0062] The inner cylinder 22A includes flange portions 222a and 222b, similar to the first embodiment. However, in this embodiment, unlike the first embodiment, each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 in a direction corresponding to left and right. More specifically, each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 toward the outside of the vehicle body in a direction corresponding to left and right. In the direction corresponding to front and rear, the positions of the flange portions 222a and 222b coincide with the position of the central axis A of the inner cylinder 22A.

[0063] The outer cylinder 21A includes a recess 212. The recess 212 is formed in the side wall of the outer cylinder 21A. The recess 212 has a concave shape on the side facing the inner cylinder body 221. The recess 212 includes, for example, a bottom portion 212a facing the inner cylinder body 221. Preferably, the bottom portion 212a is substantially parallel to the outer circumferential surface of the inner cylinder body 221 when viewing the outer cylinder 21A and inner cylinder 22A in a cross-section including the central axis A. When viewing the outer cylinder 21A and inner cylinder 22A in a cross-section including the central axis A, the recess 212 is provided on at least the flange portion 222a, 222b side of the side wall of the outer cylinder 21A. In the example shown in Figures 7 and 8, the recess 212 is provided around the entire circumference of the side wall of the outer cylinder 21A.

[0064] Figure 9 is a diagram illustrating the operation of the bush 20A. Similar to the first embodiment, when a load is applied to the structural member 100A from the front of the vehicle body, the inner cylinder 22A moves relative to the outer cylinder 21A. As shown in Figure 9, the inner cylinder 22A moves relative to the outer cylinder 21A, mainly in the left-right direction, from a state where the central axes of the outer cylinder 21A and the inner cylinder 22A coincide.

[0065] The openings 211a and 211b of the outer cylinder 21A receive the flange portions 222a and 222b of the inner cylinder 22A, respectively, before the relative distance traveled by the outer cylinder 21A and the inner cylinder 22A exceeds 60% of the range of motion R. As a result, as shown by the dashed line in Figure 9, when the inner cylinder 22A attempts to rotate relative to the outer cylinder 21A around an axis corresponding to the front-rear direction, the flange portions 222a and 222b contact the edges of the openings 211a and 211b, thereby restricting the rotation.

[0066] When the outer cylinder 21A and the inner cylinder 22A approach each other, the elastic body 23 is compressed and hardened between the recess 212 of the outer cylinder 21A and the inner cylinder body 221. The recess 212 of the outer cylinder 21A is supported by the hardened elastic body 23 when the inner cylinder 22A attempts to rotate relative to the outer cylinder 21A around an axis corresponding to the front-rear direction, thereby suppressing such rotation.

[0067] Thus, in this embodiment as well, similar to the first embodiment, when the distance the outer cylinder 21 and inner cylinder 22 have moved relative to each other is within 60% of the range of motion R, the restriction of the relative rotation of the inner cylinder 22A with respect to the outer cylinder 21A, with respect to the front-rear direction as the axis, begins. In the bush 20A according to this embodiment as well, the openings 211a and 211b of the outer cylinder 21A receive the flange portions 222a and 222b of the inner cylinder 22A, thereby restricting the relative rotation of the inner cylinder 22A with respect to the outer cylinder 21A, with respect to the front-rear direction as the axis. As a result, the bush 20A can enable the structural member 100A to exhibit excellent resistance to the front-rear load of the automobile.

[0068] In this embodiment as well, by setting the clearance between the edges of the openings 211a, 211b of the outer cylinder 21A and the flange portions 222a, 222b of the inner cylinder 22A, it is possible to make rotation around the front-to-back direction less likely to occur with respect to the relative rotation of the inner cylinder 22A with respect to the outer cylinder 21A compared to rotation around the left-to-right direction. That is, the allowable rotation angles for rotation around the left-to-right direction and rotation around the front-to-back direction can be determined, and the clearance between the edges of the openings 211a, 211b and the flange portions 222a, 222b can be geometrically determined according to these rotation angles. In this embodiment, the height of the openings 211a, 211b of the outer cylinder 21 can be, for example, 1.20 times or less the thickness of the flange portions 222a, 222b of the inner cylinder 22 (height of openings 211a, 211b / thickness of flange portions 222a, 222b ≤ 1.20). The width of the openings 211a and 211b can be, for example, 1.50 times or more the width of the flange portions 222a and 222b (width of openings 211a and 211b / width of flanges 222a and 222b ≥ 1.50).

[0069] Furthermore, in this embodiment, when the outer cylinder 21A and the inner cylinder 22A approach each other in the left-right direction, the portion of the elastic body 23 located in the left-right direction (outside the vehicle body) relative to the inner cylinder 22A is compressed and hardened between the recess 212 of the outer cylinder 21A and the inner cylinder body 221, while the portion located in the front-rear direction relative to the inner cylinder 22A is less likely to be compressed. As a result, relative rotation of the outer cylinder 21A and the inner cylinder 22A around the left-right direction is more easily tolerated compared to relative rotation of the outer cylinder 21A and the inner cylinder 22A around the front-rear direction.

[0070] <Third Embodiment> Figure 10 is a longitudinal cross-sectional view (cross-sectional view including the central axis A) of the bush 20B included in the structural member 100B according to the third embodiment. Figure 11 is a transverse cross-sectional view (XI-XI cross-sectional view) of the bush 20B. The structural member 100B according to this embodiment has a member body 10 similar to the structural members 100 and 100A according to the other embodiments. However, the bush 20B has a different configuration from the bushes 20 and 20A of the other embodiments.

[0071] Referring to Figures 10 and 11, the bush 20B according to this embodiment includes an outer cylinder 21B and an inner cylinder 22B.

[0072] The inner cylinder 22B includes flange portions 222a and 222b, as in other embodiments. In this embodiment, each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 in a direction corresponding to the left and right, as in the second embodiment. Each of the flange portions 222a and 222b protrudes from the inner cylinder body 221 toward the outside of the vehicle body in a direction corresponding to the left and right. In the direction corresponding to the front and rear, the positions of the flange portions 222a and 222b coincide with the position of the central axis A of the inner cylinder 22B.

[0073] The inner cylinder body 221 includes a protrusion 223. The protrusion 223 is formed on the side wall of the inner cylinder body 221. The protrusion 223 has a convex shape toward the outer cylinder 21B. The protrusion 223 includes, for example, a top portion 223a facing the outer cylinder 21B. Preferably, the top portion 223a is substantially parallel to the inner circumferential surface of the outer cylinder 21B when viewed in a cross-section including the central axis A, with respect to the outer cylinder 21B and inner cylinder 22B. When viewed in a cross-section including the central axis A, the protrusion 223 is provided on at least the flange portion 222a, 222b side of the side wall of the inner cylinder body 221. In the example shown in Figures 10 and 11, the protrusion 223 is provided around the entire circumference of the side wall of the inner cylinder body 221.

[0074] Figure 12 is a diagram illustrating the operation of the bush 20B. As in other embodiments, when a load is applied to the structural member 100B from the front of the vehicle body, the inner cylinder 22B moves relative to the outer cylinder 21B. As shown in Figure 12, the inner cylinder 22B moves relative to the outer cylinder 21B, mainly in the left-right direction, from a state where the central axes of the outer cylinder 21B and the inner cylinder 22B are aligned.

[0075] The openings 211a and 211b of the outer cylinder 21B receive the flange portions 222a and 222b of the inner cylinder 22B, respectively, before the relative distance traveled by the outer cylinder 21B and the inner cylinder 22B exceeds 60% of the range of motion R. As a result, as shown by the dashed line in Figure 12, when the inner cylinder 22B attempts to rotate relative to the outer cylinder 21B around an axis corresponding to the front-rear direction, the flange portions 222a and 222b contact the edges of the openings 211a and 211b, thereby restricting the rotation.

[0076] When the outer cylinder 21B and the inner cylinder 22B approach each other, the elastic body 23 is compressed and hardened between the outer cylinder 21B and the protrusion 223 of the inner cylinder body 221. The protrusion 223 is supported by the hardened elastic body 23 when the inner cylinder 22B attempts to rotate relative to the outer cylinder 21B around an axis corresponding to the front-rear direction, thereby suppressing the rotation.

[0077] Thus, in this embodiment as well, as in other embodiments, when the distance the outer cylinder 21 and inner cylinder 22 have moved relative to each other is within 60% of the range of motion R, the restriction of the relative rotation of the inner cylinder 22B with respect to the outer cylinder 21B, with respect to the longitudinal direction as the axis, begins. In the bush 20B according to this embodiment as well, the openings 211a and 211b of the outer cylinder 21B receive the flange portions 222a and 222b of the inner cylinder 22B, thereby restricting the relative rotation of the inner cylinder 22B with respect to the outer cylinder 21B, with respect to the longitudinal direction as the axis. As a result, the bush 20B can enable the structural member 100A to exhibit excellent resistance to longitudinal loads of the automobile.

[0078] In this embodiment as well, by setting the clearance between the edges of the openings 211a, 211b of the outer cylinder 21B and the flange portions 222a, 222b of the inner cylinder 22B, it is possible to make rotation around the front-to-back direction less likely to occur relative to the outer cylinder 21B compared to rotation around the left-to-right direction. That is, the allowable rotation angles for rotation around the left-to-right direction and rotation around the front-to-back direction can be determined, and the clearance between the edges of the openings 211a, 211b and the flange portions 222a, 222b can be geometrically determined according to these rotation angles. In the example of this embodiment, the dimensions of the openings 211a, 211b and the flange portions 222a, 222b can be set in the same way as in the second embodiment.

[0079] Furthermore, in this embodiment, when the outer cylinder 21B and the inner cylinder 22B approach each other in the left-right direction, the portion of the elastic body 23 located in the left-right direction (outside the vehicle body) relative to the inner cylinder 22B is compressed and hardened between the outer cylinder 21B and the convex portion 223 of the inner cylinder body 221, while the portion located in the front-rear direction relative to the inner cylinder 22B is less likely to be compressed. As a result, relative rotation of the outer cylinder 21B and the inner cylinder 22B around the left-right direction is more easily tolerated compared to relative rotation of the outer cylinder 21B and the inner cylinder 22B around the front-rear direction.

[0080] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0081] In each of the above embodiments, the flange portions 222a and 222b of the inner cylinder contact the edges of the openings 211a and 211b of the outer cylinder, thereby restricting the relative rotation of the inner cylinder with respect to the outer cylinder, with respect to the axis corresponding to the front-rear direction. The contact between the outer cylinder and the inner cylinder at this time may be direct metal-to-metal contact, or it may be indirect metal-to-metal contact with, for example, a cushioning material interposed therebetween. That is, a cushioning material or the like may be provided on at least one of the edges of the flange portions 222a and 222b or the openings 211a and 211b.

[0082] In the bushes 20, 20A, and 20B according to the above embodiment, two flange portions 222a and 222b are provided on the inner cylinder body 221. However, in the bushes 20, 20A, and 20B, only one of the flange portions 222a and 222b may be provided on the inner cylinder body 221, or three or more flange portions may be provided on the inner cylinder body 221. However, in order to easily restrict the relative rotation of the inner cylinder with respect to the outer cylinder about the axis corresponding to the front-rear direction, it is preferable that the inner cylinder body 221 be provided with multiple flange portions. The outer cylinder may have one or more openings formed therein corresponding to one or more flange portions provided on the inner cylinder body 221.

[0083] In the bushes 20, 20A, and 20B according to the above embodiment, the inner cylinder includes flange portions 222a and 222b, while the outer cylinder includes openings 211a and 211b. However, for example, the outer cylinder may include one or more flange portions, and the inner cylinder may include openings for receiving the flange portions. Alternatively, both the outer cylinder and the inner cylinder may include flange portions.

[0084] In each of the above embodiments, the flange portions 222a and 222b of the inner cylinder contact the edges of the openings 211a and 211b of the outer cylinder, thereby restricting the relative rotation of the outer cylinder and the inner cylinder. However, the contact portion of the inner cylinder with respect to the outer cylinder for restricting the relative rotation of the outer cylinder and the inner cylinder does not necessarily have to be a flange portion. [Examples]

[0085] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the following examples.

[0086] To confirm the effects of this disclosure, a deformation analysis was performed on a structural member (lower arm) having a shape similar to the structural member 100 shown in Figure 1, using commercially available analysis software (Abaqus CAE, manufactured by HKS Corporation), when a forced displacement was applied from front to rear near the connection point between the structural member and the wheel.

[0087] In the comparative example, the bush attached to the mounting portion 13 of the structural member allowed relative rotation of the outer cylinder and inner cylinder around the corresponding front-to-back, left-to-right, and up-to-down directions. In Example 1, for the same bush as in the comparative example, the rigidity of relative rotation of the outer cylinder and inner cylinder around the corresponding front-to-back direction was set to 10 times that of the comparative example. 6 The constraint was doubled. In Example 2, in addition to the relative rotation of the outer and inner cylinders around the front-to-back axis, the rigidity of the relative rotation of the outer and inner cylinders around the up-to-down axis was set to 10 times that of the comparative example. 6 They were restrained twice as much.

[0088] Figure 13 shows the load-displacement curve of the structural member obtained in this analysis. As shown in Figure 13, in Example 1, where the relative rotation of the outer and inner cylinders around the longitudinal axis was constrained, the maximum load was higher compared to the comparative example. In Example 2, where the relative rotation of the outer and inner cylinders around the vertical axis was also constrained in addition to the longitudinal axis, the maximum load increased even further. Therefore, in order to increase the maximum load (bearing capacity) against longitudinal loads of an automobile, it is sufficient to restrict the relative rotation of the inner cylinder with respect to the outer cylinder around the longitudinal axis, and it is more preferable to restrict the relative rotation of the inner cylinder with respect to the outer cylinder around both the longitudinal and vertical axes.

[0089] Regarding Example 2, further analysis was conducted by changing the timing of the constraint on the relative rotation of the outer and inner cylinders. The results are shown in Table 1.

[0090] [Table 1]

[0091] In Table 1, the relative displacement at the start of constraint refers to the radial relative displacement between the inner surface of the outer cylinder and the outer surface of the inner cylinder at the point when constraint on relative rotation around the corresponding front-to-back and up-to-down axes is initiated. That is, the initial position is defined as the state where the central axes of the outer cylinder and the inner cylinder coincide, and the relative displacement at the start of constraint is the distance the inner cylinder has moved (approached) radially relative to the outer cylinder from the initial position at the time the constraint on relative rotation begins. The range of motion is the difference between the inner diameter of the outer cylinder and the outer diameter of the inner cylinder.

[0092] As shown in Table 1, if the relative displacement at the start of restraint was within 60% of the range of motion, the maximum load could be increased by more than 5% compared to the comparative example. Therefore, it can be said that the restriction of the relative rotation of the outer and inner cylinders should be started before the relative travel distance (displacement) of the outer and inner cylinders exceeds 60% of the range of motion. [Explanation of Symbols]

[0093] 100, 100A, 100B: Structural members 10: Main component 20, 20A, 20B: Bushings 21, 21A, 21B: Outer cylinder 211a, 211b: Opening 212: Recess 22,22A,22B: Inner cylinder 221: Inner cylinder body 222a, 222b: Flange section 223: Convex part

Claims

1. These are bushings for automobiles, Outer cylinder and An inner cylinder positioned inside the outer cylinder, An elastic body filled between the outer cylinder and the inner cylinder, Equipped with, When the difference between the distance from the central axis of the outer cylinder to the inner surface of the outer cylinder and the distance from the central axis of the inner cylinder to the outer surface of the inner cylinder is defined as the relative range of motion of the outer cylinder and the inner cylinder, When the distance the inner cylinder moves relative to the outer cylinder from a state in which the central axis of the inner cylinder coincides with the central axis of the outer cylinder is within 60% of the range of motion, the relative rotation of the outer cylinder and the inner cylinder is restricted so that, compared to the relative rotation of the inner cylinder with respect to the outer cylinder with respect to the left-right direction corresponding to the left-right direction of the vehicle when the bush is attached to the vehicle, the relative rotation of the inner cylinder with respect to the outer cylinder with respect to the front-rear direction corresponding to the front-rear direction of the vehicle when the bush is attached to the vehicle is less likely to occur. A bush in which the relative rotation of the inner cylinder with respect to the outer cylinder, with respect to the aforementioned front-to-back direction as the axis, is restricted by the inner cylinder contacting the outer cylinder.

2. A bush according to claim 1, A bush in which, when the relative distance traveled between the outer cylinder and the inner cylinder is within 60% of the range of motion, the relative rotation of the inner cylinder with respect to the outer cylinder is restricted along the front-to-back axis, and the relative rotation of the inner cylinder with respect to the outer cylinder is restricted along the up-and-down axis, which corresponds to the up-and-down direction of the vehicle when the bush is attached to the vehicle.

3. A bush according to claim 1, The inner cylinder includes a cylindrical inner cylinder body and a flange portion that protrudes from the outer circumferential surface of the inner cylinder body toward the outer cylinder. The outer cylinder is a bush, which includes an opening formed in the side wall of the outer cylinder to receive the flange portion when the relative travel distance between the outer cylinder and the inner cylinder is within 60% of the range of motion.

4. The bush according to claim 3, The inner cylinder includes a plurality of flange portions arranged spaced apart in the axial direction of the inner cylinder, The outer cylinder is a bush, which includes a plurality of openings corresponding to a plurality of flange portions.

5. The bush according to claim 3, The flange portion is a bush that protrudes from the outer circumferential surface of the inner cylinder body in the direction corresponding to the front and rear.

6. The bush according to claim 5, The flange portion is a bush, which is positioned offset in the left-right direction relative to the central axis of the inner cylinder.

7. The bush according to claim 3, The flange portion protrudes from the outer circumferential surface of the inner cylinder body in the direction corresponding to the left and right, The outer cylinder is a bush that, when viewed in a cross-section including the central axis of the outer cylinder, includes a recess formed in at least the flange portion of the side wall of the outer cylinder and having a concave shape on the inner cylinder body side.

8. The bush according to claim 3, The flange portion protrudes from the outer circumferential surface of the inner cylinder body in the direction corresponding to the left and right, The inner cylinder body is a bush that, when viewed in a cross-section including the central axis of the inner cylinder, includes a protrusion formed on at least the flange portion side of the side wall of the inner cylinder body, which has a shape that protrudes toward the outer cylinder.

9. A structural component for automobiles, A bush according to any one of claims 1 to 8, The member body to which the bush is attached, A structural member equipped with the following features.

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