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-isolating device, and more particularly to a vibration-isolating device that can ensure the durability of elastic legs while being compact. [Background technology]

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

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-196850 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 cylindrical member in order to miniaturize the vibration-damping 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 an object of the present invention is to provide a vibration-damping device that can ensure the durability of the elastic legs while also 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 material that connect an inner peripheral surface of the tubular member and an outer peripheral surface of the shaft member and that widen from each other in a second direction perpendicular to a first direction as viewed in the axial direction of the shaft member, as the elastic legs extend in a first direction in the axial direction of the shaft member; 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 the elastic legs extend in the first direction; and 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 that extend parallel to the first direction in the axial view, and a pair of The elastic leg member has a pair of inclined surfaces each extending from a parallel surface in the first direction, and the connecting surface and the inclined surfaces connected by the elastic leg member are parallel to each other when viewed in the axial direction, or the distance between them narrows as they extend toward the first direction.When the width of the elastic leg member is defined as the straight-line distance from a first intersection between the inclined surface and a first virtual line that is a linear extension of a first outer contour line of the elastic leg member on the first direction side, to a second intersection between the parallel surface and a second virtual line that is a linear extension of a second outer contour line of the elastic leg member on the opposite side of the first direction, the boundary between the parallel surface and the inclined surface is located at a distance of more than 2 / 3 of the width of the elastic leg member from the first intersection point. [Effects of the Invention]

[0007] According to the vibration-damping device described in claim 1, the inner peripheral surface of the tubular member at the positions where the pair of elastic legs are connected includes a pair of parallel surfaces extending parallel to the first direction in an axial view, and a pair of inclined surfaces extending in the first direction from the pair of parallel surfaces. The connecting surfaces and the inclined surfaces on the outer peripheral surface of the shaft member connected by the elastic legs are parallel to each other in an axial view, or the distance between them narrows as they extend toward the first direction. Because the distance between the pair of connecting surfaces in the second direction narrows as they extend 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. If the thickness of the tubular member is sufficient to ensure its strength, the width of the tubular member in the second direction is determined by the maximum distance between the inner peripheral surfaces of the tubular member in the second direction. Therefore, providing parallel surfaces allows the width of the tubular member in the second direction to be smaller than when the inclined surfaces extend in the opposite direction from the first direction without providing parallel surfaces on the inner peripheral surface of the tubular member. In other words, the parallel surfaces allow for a more compact vibration-damping device.

[0008] The width of the elastic leg is defined as the linear distance from the first intersection of a first virtual line, a linear extension of the first outline of the elastic leg on the first direction side, with the inclined surface to the second intersection of a second virtual line, a linear extension of the second outline of the elastic leg on the opposite side of the first direction, with the parallel surface. The boundary between the parallel surface and the inclined surface is located at a distance of at least two-thirds of the width of the elastic leg from the first intersection. This facilitates 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 tubular member in the first direction, to escape toward the parallel surface, dispersing strain in the elastic leg. As a result, the durability of the elastic leg can be ensured even if the free length of part of the elastic leg is shortened by the parallel surface used to reduce the size of the vibration-damping device. This allows both ensuring the durability of the elastic leg and miniaturizing the vibration-damping device.

[0009] According to the vibration-damping device of claim 2, when viewed in the axial direction, 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. As a result, in addition to the effect of claim 1, it is possible to distribute strain that occurs in the elastic leg portion and improve the durability of the elastic leg portion.

[0010] According to the vibration-damping device of claim 3, the inner peripheral surface of the tubular member is provided with a stopper surface located in the first direction of the shaft member. This stopper surface restricts relative displacement of the shaft member in the first direction with respect to the tubular member. A portion of the elastic leg is connected to a concave surface that connects both circumferential sides of the stopper surface to a pair of inclined surfaces and is recessed in the first direction relative to the stopper surface. This achieves the effects of claim 1 or 2, and also makes it possible to lengthen the free length of the elastic leg in the first direction, thereby improving the durability of the elastic leg.

[0011] [Brief explanation of the drawings]

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

[0013] Preferred embodiments will now be described with reference to the accompanying drawings. Fig. 1 is a plan view of an anti-vibration device 10 according to 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 cross-sectional end view of the anti-vibration device 10 taken along line III-III in Fig. 1.

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

[0015] The vibration-damping 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 to connect the outer circumferential surface of the shaft member 11 and the 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 extend 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 so that the inside of the inner circumferential surface 22 of the tubular member 20 is approximately symmetrical on both sides of the second direction B with respect to the axis C. 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 has a pair of connecting surfaces 11a to which the pair of elastic leg portions 13 are respectively connected by vulcanization bonding, 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 peripheral surface of the shaft member 11. This makes it difficult for the elastic leg portions 13 and the second stopper 15 to peel off from the outer peripheral 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 as they extend toward the first direction A. In this embodiment, the connecting surfaces 11a are formed in a substantially linear shape when viewed in the axial direction. Note that if there are multiple linear portions when viewed in the axial direction on the outer peripheral surface of the shaft member 11 at the position where the elastic leg portions 13 are connected, the linear 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 peripheral surface of the shaft member 11 that is provided on the side opposite to the first direction A, and is recessed toward the first direction A. This ensures the free length in the first direction A of the second stopper 15 that is 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 circumferential 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 decreases toward the opposing inner circumferential surface 22. This reduces the spring constant of the second stopper 15 in the initial stage of contact between the second stopper 15 and the inner circumferential surface 22, and allows the spring constant of the second stopper 15 to increase sharply in response to the amount of relative displacement of the tubular member 20 in the first direction A with respect to the shaft member 11. This suppresses abnormal noise when the second stopper 15 contacts the inner circumferential surface 22, and improves the displacement restriction effect of 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 of the tubular member 20 from the inner peripheral surface 22 to the outer peripheral surface 21 is determined depending on the material from which the tubular member 20 is made and the strength required for the tubular member 20. When the tubular member 20 is made of an aluminum alloy, the tubular member 20 needs to be formed relatively thick. When a thick tubular member 20 is cast, defects such as blowholes are more likely to occur. To prevent blowholes and reduce weight, the tubular member 20 has multiple lightening grooves 24 on both sides of its axial end face. In addition, to prevent rainwater and the like from accumulating in the lightening grooves 24, the tubular member 20 has through holes 25 that axially penetrate the bottom surfaces of the lightening grooves 24.

[0024] The inner surface 22 of the tubular member 20 comprises 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 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 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 portion of the elastic leg portion 13 on the side opposite to the first direction A is connected to the parallel surface 22a by vulcanization adhesion. The parallel surface 22a is located at the outermost position 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 between 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 that smoothly connect to the parallel surface 22a and the concave surface 22d, formed in a substantially linear 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 parallel surfaces 22a are not provided on the inner circumferential surface 22 of the tubular member 20 and the inclined surfaces 22b are extended in the direction opposite to the first direction A, the width of the tubular member 20 in the second direction B can be made smaller by providing the parallel surfaces 22a. In other words, the parallel surfaces 22a allow the vibration-damping 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, which are connected by the elastic leg portions 13, narrows as they move 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 portions 13 are compressed between the connecting surface 11a and the inclined surface 22b, and the elastic leg portions 13 expand in the axial direction. If the expansion of the elastic leg portions 13 is uneven in the width direction (the circumferential direction of the shaft member 11), strain may be concentrated in a part of the elastic leg portions 13, reducing the durability of the elastic leg portions 13.

[0029] However, in this embodiment, as viewed in the axial direction, 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 not more than 10°. 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 strain generated in the elastic leg portion 13 is dispersed, and the durability of the elastic leg portion 13 can be improved.

[0030] It should be noted that when the angle θ is approximately 5°, strain 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, strain 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 for 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 vulcanization-bonded to the stopper surface 22c. The first stopper 14 has a total of three protrusions that face the shaft member 11 and the pair of elastic legs 13. The tips of these protrusions face the elastic membrane provided on the inner circumferential surface of the shaft member 11 and the pair of elastic legs 13, with a gap between them. Furthermore, the three protrusions of the first stopper 14 are tapered toward the tips. This, like the second stopper 15, can suppress abnormal noise when the first stopper 14 comes into contact with the shaft member 11 and the pair of elastic legs 13, and can improve the displacement-restricting effect of the first stopper 14.

[0033] The concave surface 22d is a portion that is recessed in the first direction A relative to the stopper surface 22c. A portion of the elastic leg portion 13 is also connected to this 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 increase the free length of the elastic leg portion 13 in the first direction A. This can improve the durability of the elastic leg portion 13.

[0034] The pair of elastic leg portions 13 are members arranged in a V-shape when viewed in the axial direction so as to widen in the second direction B as they extend from the shaft member 11 in the first direction A. The radially inner ends of the elastic leg portions 13 are vulcanization bonded to the outer peripheral surface (connecting surface 11a) of the shaft member 11, and the radially outer ends are vulcanization bonded to the inner peripheral 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 portion 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 portion 13 to peel off from the inner circumferential surface 22 as the elastic leg portion 13 deforms. Furthermore, since the radially outer end of the elastic leg portion 13 is connected to the first stopper 14, it is similarly possible to make it difficult for the elastic leg portion 13 to peel off from the inner circumferential surface 22 as the elastic leg portion 13 deforms.

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

[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, which are 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) that is larger than the axial dimension on the tubular member 20 side (radially outer side). As a result, the spring of the vibration-damping device 10 is restricted by the elastic leg portions 13 on the tubular member 20 side, which have a smaller axial dimension. Furthermore, the shaft member 11 extends farther axially toward the other side C2 than toward one side C1 relative to the tubular member 20. Therefore, the elastic leg portions 13 extend farther axially toward the other side C2 than toward one side C1 relative to the tubular member 20.

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

[0039] Returning to FIG. 1 , when viewed in the axial direction, 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 22 b) of the tubular member 20 is defined as a first intersection 27. Similarly, when viewed in the axial direction, the outline of the elastic leg 13 on the side opposite 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 22 a) is defined as a second intersection 28. Note that the first outline 31 and the second outline 35 of the elastic leg 13 are the outlines of the portion excluding the radially outer end of the elastic leg 13, which is bent significantly 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 at least 2 / 3 of the width L of the elastic leg portion 13 from the first intersection 27. More specifically, when viewed in the axial direction, an imaginary line perpendicular to the line segment connecting the first intersection 27 and the second intersection 28 is drawn at a position 2L / 3 from the first intersection 27 of that line segment, the boundary 26 is located on that imaginary line or on the second intersection 28 side of the imaginary line.

[0041] This makes it easier for 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, to escape toward the parallel surface 22a, thereby dispersing the strain that occurs in the elastic legs 13. This ensures the durability of the elastic legs 13 even if the free length of part of the elastic legs 13 is shortened by the parallel surface 22a that is used to reduce the size of the vibration-damping device 10. Therefore, it is possible to ensure the durability of the elastic legs 13 and to reduce the size of the vibration-damping 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, first end portion 40, and second end portion 50 are integrally molded 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 contour 31. The central portion 30 also forms a second outer contour 35 with 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 portion 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 axial side C2 and the circumferential direction (opposite the first direction A) relative to a virtual fillet surface F1 that smooths 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 that are continuous with the end edges 32, 42, respectively, and a concave surface 44 that connects 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 Figure 3. Compared to the case where the concave surface 44 is not present, the presence of the concave surface 44 allows the first wall surface 43 to be recessed deeper relative to the virtual fillet surface F1.

[0046] 3, the second end 50 has a second wall surface 53 continuous with 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 smooths the corner of an edge where a virtual surface extending from the 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 the edge 52 on the first direction A side of the other end surface 51.

[0047] The second wall surface 53 has two convex surfaces that are continuous with the end edges 33, 52, respectively, and a concave surface 54 that connects 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 Figure 3. Compared to the case where the concave surface 54 is not present, the presence of the concave surface 54 allows the second wall surface 53 to be recessed deeper relative to the virtual fillet surface F2.

[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 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 when the first wall surface 43 and the second wall surface 53 are not present (in 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 occurring in the elastic leg portion 13 more uniform between the one side C1 and the other side C2, for example, when the elastic leg portion 13, which extends farther toward the other side C2 than toward the one side C1 with respect to the tubular member 20 (see FIG. 2), undergoes torsional deformation. As a result, the maximum strain occurring in the elastic leg portion 13 can be made smaller, and the durability of the elastic leg portion 13 can be further 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] Strain in the tensile direction of the elastic leg portions 13 may concentrate in the elastic leg portions 13 near the concave surface 22d. As described above, the first wall surface 43 and the second wall surface 53 are provided up to the elastic leg portions 13 on the concave surface 22d, which makes it difficult for strain in the tensile direction of the elastic leg portions 13 to concentrate in the vicinity of the concave surface 22d. Therefore, by providing the first wall surface 43 and the second wall surface 53 up to the vicinity of the concave surface 22d, it is possible to easily distribute strain in the tensile direction of the elastic leg portions 13, and further improve the durability of the elastic leg portions 13.

[0052] Furthermore, when viewed in the axial direction, the radially outer end of concave surface 44 extends toward concave surface 22d. Similarly, although not shown, when viewed in the axial direction, the radially outer end of concave surface 54 extends toward concave surface 22d. This makes it even more difficult for the tensile strain 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 embodiments, it is not limited to the above embodiments, and it is easily understood that various improvements and modifications are possible within the scope of the present invention. The shapes and dimensions of the shaft member 11, tubular member 20, connecting member 18, elastic leg portion 13, first stopper 14, second stopper 15, etc. may be changed as appropriate.

[0054] Furthermore, the vibration damping device 10 is not limited to being a part of a torque rod, and the connecting member 18 may be omitted and the vibration damping device 10 may be a so-called bushing.The vibration damping device 10 is not limited to being an engine mount that elastically supports an engine, and the vibration damping device 10 of the above form may be applied to a vibration damping 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 cylindrical 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 cylindrical member 20 may be made of a metal other than an aluminum alloy, such as steel. Furthermore, the shaft member 11 and the cylindrical member 20 may be made of a synthetic resin.

[0056] In the above embodiment, the case has been described in which the distance between the inclined surface 22b and the connecting surface 11a connected by the elastic leg portion 13 narrows as they move toward the first direction A, 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 as viewed in the axial direction.

[0057] In the above embodiment, the first wall surface 43 and the second wall surface 53 are described as having 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 a single convex surface, or the first wall surface 43 and the second wall surface 53 may be formed by only the concave surfaces 44, 54. Furthermore, the first wall surface 43 and the second wall surface 53 may be formed linearly in a circumferential cross section. <Other> <Means> The vibration-damping device of Technical Idea 1 comprises a shaft member, a tubular member disposed radially outward of the shaft member, and a pair of elastic legs made of an elastic material that connect an inner peripheral surface of the tubular member and an outer peripheral surface of the shaft member and that widen toward a first direction in a second direction perpendicular to the first direction as viewed in the axial direction of the shaft member, the outer peripheral surface of the shaft member having a pair of connecting surfaces to which the pair of elastic legs are respectively connected and whose spacing in the second direction narrows as viewed in the first direction, and 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 that extend parallel to the first direction as viewed in the axial direction and a pair of parallel surfaces that extend from the pair of parallel surfaces. and a pair of inclined surfaces each extending in the first direction from the first virtual line. The connecting surface and the inclined surfaces 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 extend toward the first direction. When the width of the elastic leg portion is defined as the straight-line distance from a first intersection of the inclined surface and a first virtual line obtained by linearly extending a first outer contour line of the elastic leg portion on the first direction side to a second intersection of the parallel surface and a second virtual line obtained by linearly extending a second outer contour line of the elastic leg portion on the opposite side from the first direction, the boundary between the parallel surface and the inclined surface is located at a distance of at least 2 / 3 of the width of the elastic leg from the first intersection point. The vibration-damping device of technical idea 2 is the vibration-damping device of technical idea 1, in which, when viewed in the axial direction, the distance between the connecting surface connected by the elastic leg portion and the inclined surface narrows as they move toward the first direction, and the angle between the connecting surface connected by the elastic leg portion and the inclined surface is 10° or less. The vibration-damping device of technical idea 3 is a vibration-damping device of technical idea 1 or 2, in which the inner surface of the tubular member is provided with a stopper surface located in the first direction of the shaft member, and concave surfaces that connect both circumferential sides of the stopper surface to a pair of the inclined surfaces and are recessed in the first direction relative to the stopper surface, and a portion of the elastic leg portion is connected to the concave surfaces. The vibration-damping device of technical idea 4 is the vibration-damping device of technical idea 3, wherein the elastic leg portion comprises a central portion located in the center of the axial direction and having a central wall surface that forms the first outline, a first end portion that forms from one axial side of the central portion to one axial end face of the elastic leg, and a second end portion that forms from the other axial side of the central portion to the other axial end face of the elastic leg, the first end portion having a first wall surface that is recessed in the axial and circumferential directions relative to a virtual fillet surface that smooths the corner of an edge where an imaginary surface extending from the central wall surface in the axial direction intersects with an imaginary surface extending in the circumferential direction from the edge of the one end face on the first direction side, and the second end portion having a second wall surface that is recessed in the axial and circumferential directions relative to a virtual fillet surface that smooths the corner of an edge where an imaginary surface extending from the central wall surface in the axial direction intersects with an imaginary surface extending in the circumferential direction from the edge of the other end face on the first direction side, and the first wall surface and the second wall surface are provided on the elastic leg portion from the shaft member to the concave surface. <Effects> According to the vibration-damping device of Technical Idea 1, the inner peripheral surface of the tubular member at the positions where the pair of elastic legs are connected includes a pair of parallel surfaces extending parallel to the first direction in an axial view, and a pair of inclined surfaces extending in the first direction from the pair of parallel surfaces. The connecting surfaces and the inclined surfaces on the outer peripheral surface of the shaft member connected by the elastic legs are parallel to each other in an axial view, or the distance between them narrows as they extend in the first direction. Because the distance between the pair of connecting surfaces in the second direction narrows as they extend in 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. If the thickness of the tubular member is sufficient to ensure its strength, the width of the tubular member in the second direction is determined by the maximum distance between the inner peripheral surfaces of the tubular member in the second direction. Therefore, providing parallel surfaces allows the width of the tubular member in the second direction to be smaller than when the inclined surfaces extend in the opposite direction from the first direction without providing parallel surfaces on the inner peripheral surface of the tubular member. In other words, the parallel surfaces allow for a more compact vibration-damping device. The width of the elastic leg is defined as the linear distance from the first intersection of a first virtual line, a linear extension of the first outline of the elastic leg on the first direction side, with the inclined surface to the second intersection of a second virtual line, a linear extension of the second outline of the elastic leg on the opposite side of the first direction, with the parallel surface. The boundary between the parallel surface and the inclined surface is located at a distance of at least two-thirds of the width of the elastic leg from the first intersection. This facilitates 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 tubular member in the first direction, to escape toward the parallel surface, dispersing strain in the elastic leg. As a result, the durability of the elastic leg can be ensured even if the free length of part of the elastic leg is shortened by the parallel surface used to reduce the size of the vibration-damping device. This allows both ensuring the durability of the elastic leg and miniaturizing the vibration-damping device. According to the vibration-damping device of Technical Idea 2, when viewed in the axial direction, 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. As a result, in addition to the effect of Technical Idea 1, it is possible to distribute the strain that occurs in the elastic leg portion and improve the durability of the elastic leg portion. According to the vibration-damping device of Technical Idea 3, the inner circumferential surface of the tubular member is provided with a stopper surface located in the first direction of the shaft member. This stopper surface restricts relative displacement of the shaft member in the first direction with respect to the tubular member. A portion of the elastic leg is connected to a concave surface that connects both circumferential sides of the stopper surface to a pair of inclined surfaces and is recessed in the first direction relative to the stopper surface. This achieves the effects of Technical Idea 1 or 2, as well as making it possible to lengthen the free length of the elastic leg in the first direction and improve the durability of the elastic leg. According to a vibration-damping device of Technical Idea 4, the elastic leg portion includes a central portion located at the center in the axial direction, a first end portion extending from one axial side of the central portion to one axial end face of the elastic leg, and a second end portion extending from the other axial side of the central portion to the other axial end face of the elastic leg. The central portion has a central wall surface forming a first outline. The first end portion includes a first wall surface recessed in the axial and circumferential directions relative to a virtual fillet surface that smooths the corner of an edge where an imaginary plane extending from the central wall surface in the axial direction intersects with an imaginary plane extending in the circumferential direction from an edge on the first direction side of the one end face. The second end portion includes a second wall surface recessed in the axial and circumferential directions relative to a virtual fillet surface that smooths the corner of an edge where an imaginary plane extending from the central wall surface in the axial direction intersects with an imaginary plane extending in the circumferential direction from an end point on the first direction side of the other end face. As a result, the first and second wall surfaces can disperse the tensile strain that occurs in the elastic legs when the tubular member displaces relative to the shaft member in the first direction. This reduces the strain compared to when the first and second wall surfaces are not present, improving the durability of the elastic legs. In particular, this tensile strain can be concentrated in the elastic legs near the concave surface. However, because the first and second wall surfaces are provided on the elastic legs from the shaft member to the concave surface, in addition to the effect of Technical Concept 3, it is possible to more easily disperse the tensile strain, further improving the durability of the elastic legs. [Explanation of symbols]

[0058] 10 Anti-vibration 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 surfaces

Claims

1. A shaft member; a cylindrical member disposed radially outward of the shaft member; a pair of elastic legs made of an elastic material that connect an inner peripheral surface of the tubular member and an outer peripheral surface of the shaft member, and that widen in a second direction perpendicular to a first direction as the legs extend in a first direction when viewed in the axial direction of the shaft member; an outer peripheral 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 having a distance therebetween that narrows 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 extend in the first direction, When viewed in the axial direction, when the width of the elastic leg is defined as the straight-line distance from a first intersection between a first virtual line, which is a linear extension of a first outline line on the first direction side of the elastic leg, and the inclined surface, to a second intersection between a second virtual line, which is a linear extension of a second outline line on the opposite side of the first direction of the elastic leg, and the parallel surface, 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 point.

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.

3. The inner circumferential surface of the cylindrical member is a stopper surface located on the shaft member in the first direction; a concave surface that connects both circumferential sides of the stopper surface and the pair of inclined surfaces and is recessed in the first direction relative to the stopper surface, 3. The vibration isolation device according to claim 1, wherein a part of the elastic leg portion is connected to the concave surface.

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