Anti-vibration device

Abstract

To provide a vibration control device capable of making ensuring durability of an elastic leg part and downsizing compatible.SOLUTION: An outer peripheral surface of a shaft member comprises a pair of connection planes between which a mutual interval in a second direction becomes narrower toward a first direction. An inner peripheral surface of a cylinder member comprises a pair of parallel planes extending in parallel with the first direction and a pair of inclined planes respectively extending in the first direction from the pair of parallel planes. The connection planes and the inclined planes which are connected by an elastic leg part are in parallel with each other or a mutual interval therebetween becomes narrower as it goes in the first direction. When a linear distance from a first intersection of a first virtual line which is obtained by linearly extending a first contour line of the elastic leg part at the side of the first direction, and the inclined plane to a second intersection of a second virtual line which is obtained by linearly extending a second contour line of the elastic leg part at an opposite side of the first direction, and the parallel plane is defined as a width of the elastic leg part, a boundary of the parallel plane and the inclined plane is located at a position separated from the first intersection by a 2 / 3 width or more of the elastic leg part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration isolation device, and more particularly to a vibration isolation device that can ensure the durability of elastic legs while being compact. [Background technology]

[0002] Conventionally, there has been known a vibration-damping device that includes an axial member, a tubular member arranged radially outward of the axial member, and a pair of elastic legs made of an elastic material such as rubber that connect the outer peripheral surface of the axial member and the inner peripheral surface of the tubular member in a V-shape (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-196850 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, simply reducing the inner and outer diameters of the tubular member in order to miniaturize the vibration isolation device poses the problem that the free length of the elastic legs becomes shorter, which tends to reduce the durability of the elastic legs.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a vibration-isolating device that can ensure the durability of the elastic legs while being compact. [Means for solving the problem]

[0006] In order to achieve this object, the vibration-damping device of the present invention comprises a shaft member, a tubular member arranged radially outward of the shaft member, and a pair of elastic legs made of an elastic body that connect an inner peripheral surface of the tubular member and an outer peripheral surface of the shaft member and that expand toward a first direction in an axial view of the shaft member, the second direction being perpendicular to the first direction. The outer peripheral surface of the shaft member has a pair of connecting surfaces to which the pair of elastic legs are respectively connected and whose spacing in the second direction narrows as it approaches the first direction. The inner peripheral surface of the tubular member at the positions where the pair of elastic legs are respectively connected has a pair of parallel surfaces extending parallel to the first direction in an axial view, and a pair of The elastic leg has a pair of inclined surfaces each extending in the first direction from a parallel surface, and the connecting surface and the inclined surfaces connected by the elastic leg are parallel to each other when viewed in the axial direction, or the distance between them narrows as they approach the first direction.When the width of the elastic leg is defined as the straight-line distance from a first intersection between a first virtual line obtained by linearly extending a first outer shape of the elastic leg on the first direction side and the inclined surface to a second intersection between a second virtual line obtained by linearly extending a second outer shape of the elastic leg on the opposite side to the first direction and the parallel surface when viewed in the axial direction, the boundary between the parallel surface and the inclined surface is located at a position more than 2 / 3 of the width of the elastic leg from the first intersection. Effect of the Invention

[0007] According to the vibration-proof device of claim 1, the inner peripheral surface of the tubular member at the position where the pair of elastic legs are connected respectively includes a pair of parallel surfaces extending parallel to the first direction in the axial view, and a pair of inclined surfaces extending from the pair of parallel surfaces in the first direction. The connecting surface and the inclined surface of the outer peripheral surface of the shaft member connected by the elastic legs are parallel to each other in the axial view, or the distance between them narrows as they move toward the first direction. Since the distance between the pair of connecting surfaces in the second direction narrows as they move toward the first direction, the distance between the pair of inclined surfaces also narrows as they move away from the parallel surfaces in the first direction. When a thickness is ensured to ensure the strength of the tubular member, the width of the tubular member in the second direction is determined by the maximum distance between the inner peripheral surface of the tubular member in the second direction, so that the width of the tubular member in the second direction can be made smaller by providing the parallel surfaces than when the inclined surfaces are extended in the opposite direction to the first direction without providing the parallel surfaces on the inner peripheral surface of the tubular member. In other words, the parallel surfaces can reduce the size of the vibration-proof device.

[0008] The width of the elastic leg is defined as the linear distance from the first intersection of the first virtual line, which is a linear extension of the first outline of the elastic leg on the first direction side, and the inclined surface to the second intersection of the second virtual line, which is a linear extension of the second outline of the elastic leg on the opposite side of the first direction, and the parallel surface. The boundary between the parallel surface and the inclined surface is located at a position 2 / 3 or more of the width of the elastic leg from the first intersection. This makes it easier to release the axial expansion of the elastic leg, which is compressed between the connecting surface and the inclined surface when the shaft member is displaced relative to the cylindrical member in the first direction, to the parallel surface, and disperses the distortion generated in the elastic leg. As a result, even if the free length of a part of the elastic leg is shortened by the parallel surface for miniaturizing the vibration-proof device, the durability of the elastic leg can be ensured. Therefore, it is possible to achieve both the durability of the elastic leg and the miniaturization of the vibration-proof device.

[0009]

[0010] tube The inner circumferential surface of the member is provided with a stopper surface located in the first direction of the shaft member. This stopper surface regulates the relative displacement of the shaft member in the first direction with respect to the cylindrical member. A part of the elastic leg portion is connected to a concave surface that connects both circumferential sides of the stopper surface with the pair of inclined surfaces and is concave in the first direction with respect to the stopper surface. As a result, , bullets The free length of the elastic leg portion can be increased in the first direction, thereby improving the durability of the elastic leg portion.

[0011] Bullet The elastic leg portion includes a central portion located at the center in the axial direction, a first end portion that forms from one axial side of the central portion to one axial end surface of the elastic leg portion, and a second end portion that forms from the other axial side of the central portion to the other axial end surface of the elastic leg portion. The central portion has a central wall surface that forms a first outline. The first end portion includes a first wall surface that is recessed in the axial direction and circumferential direction with respect to a virtual fillet surface that smooths the corner of an edge where a virtual surface extending from the central wall surface in the axial direction intersects with a virtual surface extending from an end point on the first direction side of the one end surface. The second end portion includes a second wall surface that is recessed in the axial direction and circumferential direction with respect to a virtual fillet surface that smooths the corner of an edge where a virtual surface extending from the central wall surface in the axial direction intersects with a virtual surface extending from an end point on the first direction side of the other end surface. This allows the first wall surface and the second wall surface to disperse the tensile strain that occurs in the elastic leg portion when the tubular member is displaced in the first direction relative to the shaft member. Compared to a case where the first and second walls are not provided, the strain can be reduced, and the durability of the elastic legs can be improved. In particular, the strain in the tensile direction may be concentrated in the elastic legs near the concave surface. However, since the first and second walls are provided on the elastic legs from the shaft member to the concave surface, , pull This makes it easier to disperse distortion in the tension direction, and further improves the durability of the elastic leg portions. Claim 2 According to the vibration-proof device described in the claims, the distance between the connecting surface and the inclined surface connected by the elastic leg portion narrows as the distance approaches the first direction, and the angle between the connecting surface and the inclined surface is 10° or less. This makes it possible to make the axial expansion of the elastic leg portion uniform across the width of the elastic leg portion when the shaft member is displaced relative to the tubular member in the first direction. 1 of In addition to the above effect, the durability of the elastic legs can be improved by dispersing the strain generated in the elastic legs. [Brief description of the drawings]

[0012] [Figure 1]FIG. 2 is a plan view of an anti-vibration device according to an embodiment. [Diagram 2] 2 is a half-sectional view of the vibration isolation device taken along line II-II in FIG. 1. [Diagram 3] 3 is a cross-sectional end view of the vibration isolation device taken along line III-III in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. Fig. 1 is a plan view of an anti-vibration device 10 in one embodiment. Fig. 2 is a half-sectional view of the anti-vibration device 10 taken along line II-II in Fig. 1. Fig. 3 is a cut-away end view of the anti-vibration device 10 taken along line III-III in Fig. 1.

[0014] 1, the vibration isolation device 10 is a part of a torque rod for receiving torque from the engine and restricting displacement of the engine in the roll direction during acceleration. The torque rod comprises a first vibration isolation device 10 attached to the vehicle body side and a second vibration isolation device (not shown) attached to the engine side, connected by two connecting members 18. Note that the vibration isolation device 10 may be attached to the engine side, and the second vibration isolation device may be attached to the vehicle body side.

[0015] The vibration-proof device 10 includes a shaft member 11 extending along an axis C, a cylindrical tubular member 20 arranged radially outward of the shaft member 11, a pair of elastic legs 13 arranged in a V-shape so as to connect an outer circumferential surface of the shaft member 11 and an inner circumferential surface 22 of the tubular member 20, a first stopper 14 provided on the inner circumferential surface 22 of the tubular member 20 between the pair of elastic legs 13, and a second stopper 15 provided on the outer circumferential surface of the shaft member 11 on the opposite side to the first stopper 14. The elastic legs 13, the first stopper 14, and the second stopper 15 are integrally molded from an elastic body such as rubber or a thermoplastic elastomer.

[0016] In this specification, the direction of the axis C of the shaft member 11 will be referred to simply as the axial direction, the direction perpendicular to the axis C as the radial direction, and the circumferential direction around the axis C as the circumferential direction. Furthermore, within the radial direction, the direction in which the pair of elastic legs 13 arranged in a V-shape spreads will be referred to as the first direction A, and the direction perpendicular to the first direction A will be referred to as the second direction B. The vibration-damping device 10 is formed approximately symmetrically on both sides of the second direction B with respect to the axis C on the inside of the inner circumferential surface 22 of the tubular member 20. Furthermore, in the following description, the same applies even if "in an axial view" is replaced with "in a cross section perpendicular to the axis C".

[0017] The shaft member 11 is a member formed in a substantially trapezoidal shape when viewed in the axial direction, and is made of a metal such as an aluminum alloy. The inner peripheral surface 11b of the shaft member 11 is formed in a circular shape centered on the axis C when viewed in the axial direction. The outer peripheral surface of the shaft member 11 includes a pair of connecting surfaces 11a to which the pair of elastic leg portions 13 are respectively connected by vulcanization adhesion, and a stopper concave surface 11c on which the second stopper 15 is provided.

[0018] An elastic membrane that connects the pair of elastic leg portions 13 to each other and an elastic membrane that connects the elastic leg portions 13 to the second stopper 15 are vulcanization-bonded to the outer circumferential surface of the shaft member 11. This makes it possible to prevent the elastic leg portions 13 and the second stopper 15 from peeling off from the outer circumferential surface of the shaft member 11.

[0019] The pair of connecting surfaces 11a are portions provided on both sides of the shaft member 11 in the second direction B, and the distance between them in the second direction B narrows toward the first direction A. In this embodiment, the connecting surface 11a is formed in a substantially straight line when viewed in the axial direction. When there are multiple straight line portions when viewed in the axial direction on the outer circumferential surface of the shaft member 11 at the position where the elastic leg portions 13 are connected, the straight line portion at the position where the center portions of the elastic leg portions 13 in the width direction (circumferential direction of the shaft member 11) are connected is defined as the connecting surface 11a.

[0020] The stopper concave surface 11c is a portion of the outer circumferential surface of the shaft member 11 on the side opposite to the first direction A, and is concave toward the first direction A. This ensures a free length in the first direction A of the second stopper 15 provided on the stopper concave surface 11c.

[0021] The second stopper 15 is a member that restricts excessive relative displacement of the tubular member 20 in the first direction A with respect to the shaft member 11. The second stopper 15 is vulcanization bonded to the stopper concave surface 11c. The second stopper 15 faces the inner peripheral surface 22 of the tubular member 20 with a gap in the first direction A. The width (dimension in the second direction B) of the second stopper 15 becomes smaller toward the opposing inner peripheral surface 22. This makes it possible to reduce the spring constant of the second stopper 15 in the initial stage of contact between the second stopper 15 and the inner peripheral surface 22, and to make the increase in the spring constant of the second stopper 15 according to the amount of relative displacement of the tubular member 20 in the first direction A with respect to the shaft member 11 steeper. Therefore, it is possible to suppress abnormal noise when the second stopper 15 contacts the inner peripheral surface 22, and to improve the displacement restriction effect by the second stopper 15.

[0022] The cylindrical member 20 is a member made of a metal such as an aluminum alloy. Two connecting members 18 extend from the cylindrical member 20 in the opposite direction to the first direction A, and the cylindrical member 20 and the connecting members 18 are integrally molded. The outer peripheral surface 21 of the cylindrical member 20 has a pair of outer parallel surfaces 21a provided on both sides in the second direction B. The pair of outer parallel surfaces 21a are portions that extend parallel to the first direction A when viewed in the axial direction.

[0023] The thickness from the inner peripheral surface 22 to the outer peripheral surface 21 of the tubular member 20 is determined according to the material constituting the tubular member 20 and the strength required for the tubular member 20. When the tubular member 20 is made of an aluminum alloy, it is necessary to form the tubular member 20 to be relatively thick. When a thick tubular member 20 is cast, defects such as casting holes are likely to occur. In order to prevent casting holes and reduce weight, the tubular member 20 is provided with a plurality of lightening grooves 24 on both sides of the axial end face. In addition, in order to prevent rainwater and the like from accumulating in the lightening grooves 24, a through hole 25 penetrating the bottom surfaces of the lightening grooves 24 in the axial direction is formed in the tubular member 20.

[0024] The inner surface 22 of the tubular member 20 includes a pair of parallel surfaces 22a extending parallel to the first direction A when viewed in the axial direction, a pair of inclined surfaces 22b extending from the pair of parallel surfaces 22a in the first direction A respectively so that the distance between them in the second direction B narrows, a stopper surface 22c located in the first direction A of the axial member 11, and concave surfaces 22d respectively connecting both circumferential sides of the stopper surface 22c to the pair of inclined surfaces 22b.

[0025] The pair of parallel surfaces 22a are portions formed parallel to each other when viewed in the axial direction, and are formed parallel to the outer parallel surface 21a. A part of the elastic leg portion 13 on the opposite side to the first direction A is connected to the parallel surface 22a by vulcanization adhesion. The parallel surface 22a is located on the outermost side of the inner circumferential surface 22 in the second direction B. In other words, the distance between the pair of parallel surfaces 22a is the maximum distance of the inner circumferential surface 22 in the second direction B.

[0026] The inclined surface 22b is a portion to which a part of the elastic leg portion 13 on the first direction A side is connected by vulcanization adhesion. In the present embodiment, the inclined surface 22b has a circumferential central portion, excluding both circumferential end portions smoothly connected to the parallel surface 22a and the concave surface 22d, formed in a substantially straight line shape when viewed in the axial direction.

[0027] When a thickness is ensured to ensure the strength of the tubular member 20, the width of the tubular member 20 in the second direction B is determined by the maximum value of the spacing in the second direction B of the inner circumferential surface 22 of the tubular member 20. Compared to a case in which the inner circumferential surface 22 of the tubular member 20 is not provided with parallel surfaces 22a and the inclined surfaces 22b are extended in the direction opposite to the first direction A, providing the parallel surfaces 22a makes it possible to reduce the width of the tubular member 20 in the second direction B. In other words, the parallel surfaces 22a allow the vibration-proof device 10 to be made smaller.

[0028] When viewed in the axial direction, the distance between the inclined surface 22b and the connecting surface 11a connected by the elastic leg portion 13 narrows toward the first direction A. As a result, when the shaft member 11 is displaced relative to the tubular member 20 in the first direction A, the elastic leg portion 13 is compressed between the connecting surface 11a and the inclined surface 22b, and the elastic leg portion 13 expands in the axial direction. If the elastic leg portion 13 expands unevenly in the width direction (circumferential direction of the shaft member 11), distortion may be concentrated in a part of the elastic leg portion 13, reducing the durability of the elastic leg portion 13.

[0029] However, in this embodiment, the angle θ between the circumferential center of the inclined surface 22b connected by the elastic leg portion 13 and the connecting surface 11a is greater than 0° and equal to or less than 10° when viewed in the axial direction. This makes it possible to make the axial expansion of the elastic leg portion 13 uniform across the width of the elastic leg portion 13 when the shaft member 11 is displaced relative to the tubular member 20 in the first direction A. As a result, the distortion occurring in the elastic leg portion 13 is dispersed, and the durability of the elastic leg portion 13 can be improved.

[0030] In addition, when the angle θ is about 5°, the distortion occurring in the elastic leg portions 13 can be most dispersed. Therefore, it is more preferable to set the angle θ to 2 to 8°. In this case, the distortion occurring in the elastic leg portions 13 can be more easily dispersed, and the durability of the elastic leg portions 13 can be further improved.

[0031] The stopper surface 22c is a portion where the first stopper 14 is provided, and is provided at the center of the inner circumferential surface 22 in the second direction B. The stopper surface 22c and the first stopper 14 are portions for restricting excessive relative displacement of the shaft member 11 in the first direction A with respect to the cylindrical member 20. The position of the stopper surface 22c in the first direction A is determined according to a set value of the maximum displacement amount of the shaft member 11 in the first direction A with respect to the cylindrical member 20.

[0032] The first stopper 14 is vulcanized and bonded to the stopper surface 22c. The first stopper 14 has a total of three protrusions facing the shaft member 11 and the pair of elastic legs 13. The tips of these protrusions face the elastic membrane and the pair of elastic legs 13 provided on the inner circumferential surface of the shaft member 11 with a gap therebetween. Furthermore, the three protrusions of the first stopper 14 are tapered toward the tips. As a result, like the second stopper 15, it is possible to suppress abnormal noise when the first stopper 14 contacts the shaft member 11 side and the pair of elastic legs 13, and to improve the displacement restriction effect of the first stopper 14.

[0033] The concave surface 22d is a portion recessed in the first direction A with respect to the stopper surface 22c. A part of the elastic leg portion 13 is also connected to the concave surface 22d by vulcanization adhesion. Compared to a case where both circumferential sides of the stopper surface 22c are directly connected to the inclined surface 22b and there is no concave surface 22d, the concave surface 22d can lengthen the free length of the elastic leg portion 13 in the first direction A. Therefore, the durability of the elastic leg portion 13 can be improved.

[0034] The pair of elastic leg portions 13 are members arranged in a V-shape when viewed in the axial direction so as to expand in the second direction B as they move from the shaft member 11 in the first direction A. The elastic leg portions 13 have their radially inner ends vulcanization-bonded to the outer circumferential surface (connecting surface 11a) of the shaft member 11, and their radially outer ends vulcanization-bonded to the inner circumferential surface 22 of the tubular member 20 (parallel surface 22a, inclined surface 22b, and concave surface 22d).

[0035] An elastic membrane 16 extends from the radially outer end of the elastic leg 13 in the direction opposite to the first direction A, and the elastic membrane 16 is also connected to the inner circumferential surface 22 by vulcanization adhesion. This elastic membrane 16 makes it difficult for the elastic leg 13 to peel off from the inner circumferential surface 22 as the elastic leg 13 deforms. In addition, since the radially outer end of the elastic leg 13 is connected to the first stopper 14, it is similarly difficult for the elastic leg 13 to peel off from the inner circumferential surface 22 as the elastic leg 13 deforms.

[0036] In addition, distortion is unlikely to occur at the axial end portion near the boundary (concave surface 22d) between the elastic leg portion 13 and the first stopper 14 when the elastic leg portion 13 or the first stopper 14 is deformed. Therefore, even if the axial end portion near the boundary between the elastic leg portion 13 and the first stopper 14 is omitted and a part of the tubular member 20 is exposed, it is possible to suppress a decrease in durability of the elastic leg portion 13 or the first stopper 14 caused by the exposed portion. As a result, the exposed portion near the concave surface 22d can be used as a positioning portion that comes into contact with a molding die when the elastic leg portion 13 and the first stopper 14 are vulcanized.

[0037] As shown in Fig. 2, the axial dimension of the shaft member 11 is set to be larger than the axial dimension of the tubular member 20. The elastic leg portions 13 vulcanization-bonded to the shaft member 11 and the tubular member 20 have an axial dimension on the shaft member 11 side (radially inner side) larger than the axial dimension on the tubular member 20 side (radially outer side). As a result, the spring of the vibration-proof device 10 is restricted by the elastic leg portions 13 on the tubular member 20 side, which has a smaller axial dimension. Also, the shaft member 11 extends farther toward the other side C2 in the axial direction relative to the tubular member 20 than toward one side C1. Therefore, the elastic leg portions 13 extend farther toward the other side C2 in the axial direction relative to the tubular member 20 than toward one side C1.

[0038] In addition, bulges 17 are provided on both axial sides of the radially outer end of the elastic leg 13. The bulges 17 are vulcanization bonded to both sides of the axial end face of the tubular member 20. Furthermore, the bulges 17 are provided not only on the elastic leg 13 but also on the elastic membrane 16 and the first stopper 14. The bulges 17 make it difficult for the elastic leg 13, the elastic membrane 16, and the first stopper 14 to peel off from the inner circumferential surface 22 of the tubular member 20.

[0039] Returning to FIG. 1, the description will be given. In the axial view, the outline of the elastic leg 13 on the first direction A side is defined as a first outline 31, and the intersection of a first imaginary line 34, which is a linear extension of the first outline 31, with the inner circumferential surface 22 (inclined surface 22b) of the tubular member 20 is defined as a first intersection 27. Similarly, in the axial view, the outline of the elastic leg 13 on the opposite side to the first direction A is defined as a second outline 35, and the intersection of a second imaginary line 36, which is a linear extension of the second outline 35, with the inner circumferential surface 22 (parallel surface 22a) is defined as a second intersection 28. The first outline 31 and the second outline 35 of the elastic leg 13 are defined as the outlines of the portion excluding the radially outer end of the elastic leg 13, which is bent greatly to smoothly connect to the elastic membrane 16 and the first stopper 14.

[0040] When viewed in the axial direction, the linear distance from the first intersection 27 to the second intersection 28 is defined as the width L of the elastic leg portion 13. When viewed in the axial direction, the boundary 26 between the parallel surface 22a and the inclined surface 22b of the tubular member 20 is located at a position that is 2 / 3 or more of the width L of the elastic leg portion 13 from the first intersection 27. More specifically, when viewed in the axial direction, a virtual line perpendicular to the line segment connecting the first intersection 27 and the second intersection 28 is drawn to a position 2L / 3 from the first intersection 27 of the line segment, the boundary 26 is on the virtual line or on the second intersection 28 side of the virtual line.

[0041] This makes it possible to easily release the axial expansion of the elastic legs 13, which is compressed between the connecting surface 11a and the inclined surface 22b when the shaft member 11 is displaced relative to the tubular member 20 in the first direction A, toward the parallel surface 22a, thereby dispersing the distortion occurring in the elastic legs 13. This ensures the durability of the elastic legs 13 even if the free length of a portion of the elastic legs 13 is shortened by the parallel surface 22a for reducing the size of the vibration-proof device 10. Therefore, it is possible to ensure the durability of the elastic legs 13 and to reduce the size of the vibration-proof device 10 at the same time.

[0042] As shown in Fig. 3, the elastic leg portion 13 includes a central portion 30 located at the center in the axial direction, a first end portion 40 provided on one axial side C1 of the central portion 30, and a second end portion 50 provided on the other axial side C2 of the central portion 30. The central portion 30, the first end portion 40, and the second end portion 50 are integrally formed from an elastic body and are each provided in the radial direction. In Fig. 3, the boundary line B1 between the central portion 30 and the first end portion 40 is indicated by a two-dot chain line, and the boundary line B2 between the central portion 30 and the second end portion 50 is indicated by a two-dot chain line.

[0043] The central portion 30 has a central wall surface 30a on the first direction A side. When viewed in the axial direction, this central wall surface 30a forms a first outer shape 31. The central portion 30 also forms a second outer shape 35 by a wall surface opposite to the first direction A. The first end portion 40 is a portion that forms from the central portion 30 to one axial end surface 41 (end surface on one side C1) of the elastic leg portion 13. The second end portion 50 is a portion that forms from the central portion 30 to the other axial end surface 51 (end surface on the other side C2) of the elastic leg portion 13.

[0044] The first end 40 has a first wall surface 43 continuous with the central wall surface 30a. The first wall surface 43 is a recessed surface recessed toward the other side C2 in the axial direction and in the circumferential direction (opposite the first direction A) with respect to a virtual fillet surface F1 that smoothes the corner of an edge where a virtual surface extending from the edge 32 on one side C1 of the central wall surface 30a to the central wall surface 30a intersects with a virtual surface extending in the circumferential direction (first direction A) from the edge 42 on the first direction A side of the one end surface 41.

[0045] The first wall surface 43 has two convex surfaces continuing to the end edges 32, 42, respectively, and a concave surface 44 connecting the two convex surfaces. Therefore, the direction of the concave and convex curves of the first wall surface 43 changes in the cross section (circumferential cross section) shown in Fig. 3. Compared to the case where the concave surface 44 is not present, the first wall surface 43 can be recessed deeper with respect to the virtual fillet surface F1 when the concave surface 44 is present.

[0046] 3, the second end 50 has a second wall surface 53 continuing to the central wall surface 30a. The second wall surface 53 is a recessed surface recessed toward one side C1 in the axial direction and toward the circumferential direction (the side opposite to the first direction A) with respect to a virtual fillet surface F2 that smoothes the corner of an edge where a virtual surface extending from an edge 33 on the other side C2 of the central wall surface 30a to the central wall surface 30a intersects with a virtual surface extending in the circumferential direction from an edge 52 on the first direction A side of the other end surface 51.

[0047] The second wall surface 53 has two convex surfaces continuing to the edges 33, 52, respectively, and a concave surface 54 connecting the two convex surfaces. Therefore, the direction of the concave and convex curves of the second wall surface 53 changes in the cross section shown in Fig. 3. Compared to the case where the concave surface 54 is not present, the second wall surface 53 can be recessed deeper with respect to the virtual fillet surface F2 when the concave surface 54 is present.

[0048] In this way, by providing the first wall surface 43 and the second wall surface 53 on the elastic leg portion 13, it is possible to disperse the strain in the tensile direction that occurs in the elastic leg portion 13. By dispersing the strain, it is possible to reduce the maximum strain compared to the case where the first wall surface 43 and the second wall surface 53 are not present (the case of virtual fillet surfaces F1, F2), and therefore it is possible to improve the durability of the elastic leg portion 13.

[0049] The recess of the second wall surface 53 relative to the imaginary fillet surface F2 is set larger than the axial recess of the first wall surface 43 relative to the imaginary fillet surface F1. This makes it easier to make the strain in the tensile direction generated in the elastic leg portion 13 uniform between the one side C1 and the other side C2, for example, when the elastic leg portion 13 extends farther toward the other side C2 than toward the one side C1 with respect to the tubular member 20 (see FIG. 2) and is torsionally deformed. As a result, the maximum strain generated in the elastic leg portion 13 can be made smaller, and the durability of the elastic leg portion 13 can be improved.

[0050] 1, when viewed in the axial direction, the first wall surface 43 is recessed from the first outline 31 toward the second outline 35, and is provided over approximately the entire length of the elastic leg portion 13 from the shaft member 11 to the concave surface 22d. Similarly, although not shown, when viewed in the axial direction, the second wall surface 53 is recessed from the first outline 31 toward the second outline 35, and is provided over approximately the entire length of the elastic leg portion 13 from the shaft member 11 to the concave surface 22d.

[0051] The strain in the tensile direction of the elastic legs 13 may concentrate on the elastic legs 13 near the concave surface 22d. As described above, since the first wall surface 43 and the second wall surface 53 are provided up to the elastic legs 13 of the concave surface 22d, it is possible to prevent the strain in the tensile direction of the elastic legs 13 from concentrating near the concave surface 22d. Therefore, by providing the first wall surface 43 and the second wall surface 53 up to the concave surface 22d, it is possible to easily disperse the strain in the tensile direction of the elastic legs 13, and the durability of the elastic legs 13 can be further improved.

[0052] Furthermore, the radially outer end of concave surface 44 extends toward concave surface 22d when viewed in the axial direction. Similarly, although not shown, the radially outer end of concave surface 54 extends toward concave surface 22d when viewed in the axial direction. This makes it even more difficult for the strain in the tensile direction of elastic leg portion 13 to concentrate near concave surface 22d, thereby further improving the durability of elastic leg portion 13.

[0053] 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 assumed that various improvements and modifications are possible without departing from the spirit of the present invention. The shapes and dimensions of each part, such as the shaft member 11, the tubular member 20, the connecting member 18, the elastic leg portion 13, the first stopper 14, the second stopper 15, etc., may be appropriately changed.

[0054] Furthermore, the vibration isolation device 10 is not limited to being a part of a torque rod, and the connecting member 18 may be omitted and the vibration isolation device 10 may be a so-called bush.The vibration isolation device 10 is not limited to being an engine mount that elastically supports an engine, and the above-described form of the vibration isolation device 10 may be applied to any vibration isolation device that suppresses vibration of any vibrating body, such as a body mount or a differential mount.

[0055] In the above embodiment, the shaft member 11 and the tubular member 20 are made of a metal such as an aluminum alloy, but this is not necessarily limited to this. For example, the shaft member 11 and the tubular member 20 may be made of a metal such as steel other than an aluminum alloy. The shaft member 11 and the tubular member 20 may also be made of a synthetic resin.

[0056] In the above embodiment, the distance between the inclined surface 22b and the connecting surface 11a connected by the elastic leg portion 13 narrows as the distance approaches the first direction A in the axial direction, but this is not necessarily limited to this. The inclined surface 22b and the connecting surface 11a connected by the elastic leg portion 13 may be parallel to each other in the axial direction.

[0057] In the above embodiment, the first wall surface 43 and the second wall surface 53 are provided with two convex surfaces and the concave surfaces 44, 54, but this is not necessarily limited to this. The concave surfaces 44, 54 may be omitted and the first wall surface 43 and the second wall surface 53 may be formed by one convex surface, or the first wall surface 43 and the second wall surface 53 may be formed only by the concave surfaces 44, 54. Furthermore, the first wall surface 43 and the second wall surface 53 may be formed linearly in the circumferential cross section. [Explanation of symbols]

[0058] 10. Vibration isolation device 11 Shaft member 11a Connecting surface 13 Elastic leg 20 Cylinder member 22 Inner surface 22a parallel plane 22b Slope 22c Stopper surface 22d concave 26 Boundary 27 1st intersection 28 Second intersection 30 Central part 30a Central wall 31 1st outline line 34 First Virtual Line 35 Second outline line 36 Second Virtual Line 40 First end 41 One end face 42,52 Edge 43 First Wall 50 Second end 51 Other end face 53 Second Wall A 1st direction B Second direction F1,F2 Virtual fillet surface

Claims

1. A shaft member; a cylindrical member disposed radially outward of the shaft member; a pair of elastic legs made of an elastic body that connect an inner peripheral surface of the tubular member and an outer peripheral surface of the shaft member, and that expand from each other in a second direction perpendicular to the first direction as the elastic legs extend toward a first direction when viewed in the axial direction of the shaft member, an outer circumferential surface of the shaft member includes a pair of connecting surfaces to which the pair of elastic leg portions are respectively connected, the connecting surfaces being spaced apart from each other in the second direction as the connecting surfaces extend in the first direction; The inner circumferential surface of the cylindrical member at the position where the pair of elastic leg portions are respectively connected is A pair of parallel surfaces extending parallel to the first direction when viewed in the axial direction; a pair of inclined surfaces extending in the first direction from the pair of parallel surfaces, The connecting surface and the inclined surface connected by the elastic leg portion are parallel to each other when viewed in the axial direction, or the distance between them narrows as they approach the first direction, when viewed in the axial direction, when a straight-line distance from a first intersection point between a first virtual line, which is a linear extension of a first outer shape line of the elastic leg on the first direction side, and the inclined surface to a second intersection point between a second virtual line, which is a linear extension of a second outer shape line of the elastic leg on the opposite side to the first direction, and the parallel surface, is defined as a width of the elastic leg, a boundary between the parallel surface and the inclined surface is located at a position that is 2 / 3 or more of the width of the elastic leg from the first intersection point, The inner circumferential surface of the cylindrical member is a stopper surface located in the first direction of the shaft member; a concave surface that connects both circumferential sides of the stopper surface and the pair of inclined surfaces and is concave with respect to the stopper surface in the first direction, A portion of the resilient leg is connected to the concave surface; The elastic leg portion is a central portion having a central wall surface that defines the first outline and located at a center in an axial direction; a first end portion that forms an axial direction of the central portion from one side to one end surface of the elastic leg portion; a second end portion that forms an axial direction of the elastic leg portion from the other axial side of the central portion to the other axial end surface of the elastic leg portion, the first end portion includes a first wall surface that is recessed in the axial and circumferential directions with respect to a virtual fillet surface that smoothes a corner of an edge where a virtual surface extending from the central wall surface in the axial direction intersects with a virtual surface extending in the circumferential direction from an edge of the one end surface on the first direction side, the second end portion includes a second wall surface that is recessed in the axial and circumferential directions with respect to a virtual fillet surface that smoothes a corner of an edge where a virtual surface extending in the axial direction from the central wall surface and a virtual surface extending in the circumferential direction from an edge of the other end surface on the first direction side intersect, A vibration-isolating device, characterized in that the first wall surface and the second wall surface are provided on the elastic leg portion from the shaft member to the concave surface.

2. The vibration-damping device of claim 1, characterized in that, when viewed in the axial direction, the distance between the connecting surface connected by the elastic leg portion and the inclined surface narrows as the distance approaches the first direction, and the angle between the connecting surface connected by the elastic leg portion and the inclined surface is 10° or less.

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