JP2008095860A - Link member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a link member reduced in weight and cost while being provided with a vibration control bush capable of sufficiently reducing a twisting-directional spring constant and increasing an axial spring constant. <P>SOLUTION: In the link member 10 comprising a link body 16 composed of an arm part 12 and connecting parts 14 provided at both ends thereof, and vibration control bushes 18 provided on the connecting parts 14, each vibration control bush 18 comprises an inner cylinder 20, a cylindrical part 22 provided on the connecting part 14, and an elastic part 24 integrally molded between the outer circumferential surface of the inner cylinder 20 and the inner circumferential surface of the cylindrical part 22. The inner cylinder 20 has a swollen part 26 in an axially perpendicular direction Y at the axial center thereof, the swollen part having an outer circumferential surface formed into a convex spherical surface 28, and the inner circumferential surface part of the cylindrical part 22 surrounding the spherical surface 28 is formed into a concave spherical surface 30 concentric to the convex spherical surface 28. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a link member used by being incorporated in an automobile suspension device or the like.

  2. Description of the Related Art Conventionally, link members including vibration-proof bushes have been used in automobile suspension devices and the like. Such a link member generally includes an arm portion and connecting portions provided at both ends thereof, and the connecting portions at both ends are connected to axles or the like via vibration-proof bushes made of rubber-like elastic bodies provided at at least one of the connecting portions. And connected to the vehicle body side such as a suspension member (see Patent Documents 1 to 3 below).

  For example, Patent Document 4 below discloses a multi-link type rear suspension device shown in FIGS. 12 and 13 as a suspension device including a link member. In this suspension apparatus, an axle 62 that rotatably supports a wheel 60, one end portions 64a and 66a are swingably connected to the axle 62, and the other end portions 64b and 66b are pivoted to a suspension member 68 that is a vehicle body side member. A pair of front and rear upper links 64 and 66, which are movably connected, and one end portions 70a and 72a are swingably connected to the axle 62, and the other end portions 70b and 72b are swingably connected to the suspension member 68. A pair of front and rear lower links 70, 72, and a toe control link 74 having one end 74 a pivotably connected to the axle 62 and the other end 74 b pivotably connected to the suspension member 68. Here, the symbol F indicates the front side of the vehicle body, and the symbol H indicates the vehicle body width direction.

  The other ends 64b, 66b, 70b, 72b, 74b of the links 64, 66, 70, 72, 74 and the suspension member 68 are connected to each other through vibration-proof bushings 76, 78, 80, 82, 84, respectively. The shaft centers p1, p2, p3, p4, and p5 of each anti-vibration bush are arranged so as to be along the direction orthogonal to the longitudinal directions r1, r2, r3, r4, and r5 of each link in plan view. Has been.

  By the way, in such a link member, the vibration isolating bush is generally formed by vulcanizing a rubber-like elastic body between the inner cylinder and the outer cylinder, and the vibration isolating bush is provided in the link body. The link member is formed by press-fitting into the shape holding portion. In this case, a process for press-fitting the vibration-proof bushing into the cylindrical holding part is necessary, and the provision of the outer cylinder leads to an increase in cost and weight. Therefore, a structure in which the outer cylinder is omitted and a rubber-like elastic body is directly vulcanized and bonded to the inner peripheral surface of the cylindrical portion of the link body has been proposed (see Patent Document 3 below).

Further, as the above-described vibration-proof bushing, a bulge portion that bulges in the axially central portion of the inner cylinder in the axially central direction in order to reduce the spring constant in the twisting direction while increasing the spring constant in the axially perpendicular direction. There is also known a so-called bulge type vibration-proof bush provided with (see Patent Document 5 below).
Japanese Patent Laid-Open No. 11-166484 JP 09-254621 A JP 2000-337416 A JP 2005-112258 A JP 2004-144150 A

  In the multilink suspension device, as shown in FIG. 13, the links 64, 66, 70, 72, and 74 are set in an inclined posture in plan view. More specifically, the front lower link 70 is set to an inclined posture positioned on the vehicle front side F toward the inner side in the vehicle body width direction H in plan view, and the rear lower link 72 is set to the vehicle body width in plan view. The toe control link 74 is set to an inclined posture that is positioned on the front side F of the vehicle body in the vehicle width direction H in a plan view. Yes.

  Therefore, during traveling of the vehicle, forces in various directions are input to the vibration isolating bushes 80, 82, 84 coupled mainly to the lower links 70, 72 and the toe control link 74. For example, when the suspension device is displaced in the vertical direction with respect to the vehicle body, not only a force in the twisting direction N (see FIG. 3) but also a force in the twisting direction Z (see FIG. 4) is applied to the vibration isolating bushes 80, 82, and 84. . Further, when the suspension device is displaced in the left-right direction with respect to the vehicle body, not only the force in the direction perpendicular to the axis Y (see FIG. 4) but also the force in the axis direction X (see FIG. 4) is applied to the anti-vibration bushes 80, 82, 84. Join.

  With respect to such an input, the conventional general anti-vibration bush has a straight cylindrical shape with a constant inner cylinder diameter, so that the spring constant in the twisting direction is large. As a result, the spring constant in the vertical direction of the suspension device Because it becomes larger, it is difficult to improve the ride comfort. Further, in this conventional vibration-proof bushing, the spring constant in the axial direction is not so large, and therefore the spring constant in the left-right direction of the suspension device cannot be increased, so it is difficult to improve the steering stability of the vehicle.

  In contrast, the conventional bulge type vibration-proof bushing can reduce the spring constant in the twisting direction. However, even in the conventional bulge type, the outer cylinder is a straight cylinder with a constant inner diameter. The elastic body is compressed, and the spring constant in the twisting direction is not always sufficiently reduced. For this reason, the effect of reducing the spring constant in the vertical direction of the suspension device is also insufficient, and further improvement is required to improve riding comfort. In addition, with the conventional bulge type vibration-proof bushing, the spring constant in the axial direction cannot be increased, and therefore it is difficult to improve the steering stability of the vehicle by increasing the spring constant in the left-right direction of the suspension device. Met.

  The present invention has been made in view of such points, and includes a vibration isolating bush that can sufficiently reduce the spring constant in the twisting direction and can increase the spring constant in the axial direction, and An object of the present invention is to provide a link member that can be reduced in weight and cost.

  A link member according to the present invention includes a link body including an arm portion and a connecting portion provided at both ends of the arm portion, and a vibration isolating bush provided in at least one of the connecting portions. The anti-vibration bushing is interposed between the shaft member, the cylindrical portion provided in the connecting portion and surrounding the shaft member, and the shaft member and the cylindrical portion. A bulging portion that bulges in a direction perpendicular to the axis at a central portion in the axial direction, and an elastic portion made of a rubber-like elastic body integrally formed on the inner peripheral surface of the cylindrical portion. And the outer peripheral surface of the bulging portion is formed into a convex spherical surface, and the inner peripheral surface portion of the cylindrical portion surrounding the convex spherical surface is formed into a concave spherical surface concentric with the convex spherical surface. It is characterized by that.

  According to this configuration, the inner peripheral surface of the cylindrical portion is a concave spherical surface that is concentric with the convex spherical surface of the bulging portion of the inner cylindrical portion, so that the displacement between the convex spherical surface and the concave spherical surface can be achieved in the case of displacement in the twisting direction. The elastic portion interposed between the inner cylinder and the outer cylinder is substantially only subjected to shear deformation, and it is possible to avoid compression of the elastic portion between the inner cylinder and the outer cylinder as much as possible. Can be reduced. Further, at the time of displacement in the axial direction, the elastic portion is subjected not only to shear deformation but also compression deformation between the convex spherical surface and the concave spherical surface, so that the spring constant in the axial direction can be increased. Further, since the elastic part is directly formed integrally with the cylindrical part of the link main body and the outer cylinder is omitted, the press-fitting step becomes unnecessary, and the cost and weight can be reduced.

  In the link member of the present invention, the convex spherical surface and the concave spherical surface are arranged so that the elastic portion is not filled between the shaft member and the cylindrical portion on the axially outer side of the virtual spherical surface defined by the concave spherical surface. It is preferable to be interposed between the two. Further, both end surfaces in the axial direction of the elastic portion are formed in a curved surface shape that swells inward in the axial direction, and a virtual spherical surface defined by the concave spherical surface in the cross section along the axial direction of the shaft member has the curved surface shape. Crossing with the axial end surface, the intersection (J) of the phantom spherical surface and the axial end surface is located closer to the tubular part than the innermost point (K) on the axial end surface. Preferably it is. This reliably prevents the compression spring from being applied at the axial end portion of the elastic portion during displacement in the twisting direction, and further reduces the spring constant in the twisting direction.

  In the link member of the present invention, the cylindrical portion of the link main body is drawn in the diameter-reducing direction after the elastic portion is molded, so that the shrinkage after the molding is removed and the durability can be improved. .

  In the link member of the present invention, it is preferable that the outer surface of the link body is covered with a rubber film continuous from the elastic portion. As described above, since the elastic portion is directly formed integrally with the link body, the rubber film can be formed without increasing the number of manufacturing steps, and cationic coating for rust prevention can be omitted. Moreover, since it is a rubber film, it is hard to be damaged by scattering of gravel and the like, and is excellent in sustainability of the rust prevention effect.

  In the link member of the present invention, the arm portion is provided with a dynamic damper including a mass body and an elastic support portion that supports the mass body with respect to the arm portion, and the elastic support portion is the elastic portion. It may be formed of a rubber-like elastic body that continues from. Since the elastic portion is directly formed on the link body as described above, a dynamic damper can be formed at the same time, and therefore the dynamic damper can be incorporated without increasing the number of steps.

  With the link member of the present invention, the spring constant in the twisting direction of the vibration-proof bush can be sufficiently reduced, the spring constant in the axial direction can be increased, and the weight and cost can be reduced. be able to.

  Embodiments of the present invention will be described below with reference to the drawings.

  The link member 10 according to an embodiment of the present invention is used in the multi-link suspension device shown in FIGS. 12 and 13 described above, and more specifically, the front lower link 70 and the rear lower link. 72 and the toe control link 74. The link member 10 can also be used as the front upper link 64 or the rear upper link 66. The overall configuration of the suspension device is as described above, and a description thereof will be omitted.

  As shown in FIG. 1 and FIG. 2, the link member 10 is composed of an arm portion 12 and a pair of connecting portions 14, 14 provided at both ends of the arm portion 12. , 14 and anti-vibration bushes 18, 18 respectively.

  As shown in FIGS. 3 and 4, the anti-vibration bush 18 includes an inner cylinder 20 as a shaft member, a cylindrical portion 22 that is coaxially disposed so as to surround the inner cylinder 20, and an inner cylinder 20. And an elastic portion 24 made of a cylindrical rubber-like elastic body interposed between the cylindrical portion 22 and the cylindrical portion 22.

  The inner cylinder 12 is a cylindrical member made of metal such as iron, steel, or aluminum, and includes a bulging portion 26 that bulges around the entire circumference in the central portion in the axial direction X toward the outside in the direction perpendicular to the axis Y. . The outer peripheral surface of the bulging portion 26 forms a convex spherical surface 28. The convex spherical surface 28 is formed in the shape of a sphere that forms the axial central portion of a spherical surface having a center P on the axis A, and is a general cylindrical portion (having a constant outer diameter) at both axial end portions of the inner cylinder 20. It is formed smoothly and continuously from the outer peripheral surface 21 of the straight cylindrical portion).

  The cylindrical portion 22 is a metallic cylindrical portion provided integrally with the connecting portion 14 of the link body 16. The inner peripheral surface of the cylindrical portion 22 forms a concave spherical surface 30 whose central portion in the axial direction X surrounding the convex spherical surface 28 is concentric with the convex spherical surface 28 (that is, has a common center P). Yes. That is, the inner peripheral surface portion of the cylindrical portion 22 surrounding the bulging portion 26 is formed as a concave spherical surface 30 concentric with the convex spherical surface 28.

  In this example, the cylindrical portion 22 is formed in a bulging portion 32 in which the central portion in the axial direction X surrounding the convex spherical surface 28 bulges in a spherical shape over the entire circumference in the direction perpendicular to the axial direction Y. ing. Then, the inner peripheral surface of the bulging portion 22 is formed on the concave spherical surface 30 concentric with the convex spherical surface 28, and the outer peripheral surface of the bulging portion 22 is concentric with the convex spherical surface 28 correspondingly. A convex spherical surface 31 is formed. More specifically, the inner peripheral surface of the bulging portion 32 is formed as the concave spherical surface 30 so as to follow the convex spherical surface 28 of the inner cylinder 20 at a certain interval in the shape after drawing processing described later. Yes. The concave spherical surface 30 forms a spherical band that forms the central portion of the spherical surface, and gently from the inner peripheral surface 23a of the general cylindrical portion (straight cylindrical portion having a constant inner diameter) 23 at both axial ends of the cylindrical portion 22. It is formed continuously.

  Although not shown, in the state before drawing, the inner peripheral surface of the bulging portion 32 of the cylindrical portion 22 is not a strict concave spherical surface 30, and the center P is perpendicular to the axis A of the cylindrical portion 22. The center P is formed in a spherical shape with the center P located on the axis A as shown in FIG.

  The elastic portion 24 is integrally vulcanized and bonded to the outer peripheral surface of the inner cylinder 20 and the inner peripheral surface of the cylindrical portion 22, and the convex spherical surface 28 of the inner cylinder 20 and the concave spherical surface of the cylindrical portion 22. As shown in FIG. 4, it is formed in a spherical band shape having a substantially constant thickness in the shape after drawing.

  As shown in FIG. 5, the elastic portion 24 is filled between the inner cylinder 20 and the cylindrical portion 22 on the axially outer side X1 of the phantom spherical surface 34 defined by the concave spherical surface 30 on the cylindrical portion 22 side. It is formed not to be.

  More specifically, the elastic portion 24 has a pair of left and right axial end surfaces 25 of the elastic portion 24 exposed between the inner cylinder 12 and the axial end portions of the cylindrical portion 22 on the axially inner side X2. It is formed in the curved surface shape which swells, and here, it is curvedly formed in the circular arc shape in the cross section along the axial direction X shown in FIG. In the cross section along the axial direction, the phantom spherical surface 34 defined by the concave spherical surface 30 intersects with the curved axial end surface 25 at the intersection J, and this intersection J is the most in the axial end surface 25. An axially inner point (that is, a point corresponding to the deepest part (bottom) of the axial end face 25) K is located on the tubular part 22 side. In this example, the point K on the innermost side in the axial direction of the axial end face 25 is on a line 36 that bisects the gap between the inner cylinder 20 and the cylindrical portion 22 in the radial direction. The intersection point J is located on the outer side.

  As shown in FIG. 5, the outermost diameter (outer diameter at the apex of the bulging portion 26) D <b> 1 of the bulging portion 26 on the inner cylinder 20 side is larger than the inner diameter D <b> 2 of the general cylindrical portion 23 of the cylindrical portion 22. Also, the thickness E of the elastic portion 24 between the convex spherical surface 28 and the concave spherical surface 30 is set to be larger than the maximum bulging height G of the bulging portion 26 of the inner cylinder 20. . Thereby, while avoiding an excessive spring constant in the axial direction X, preferable spring constants in the direction perpendicular to the axis Y, the twisting direction Z, and the torsional direction N are obtained.

  The connecting portion 14 of the link body 16 is integrally provided with the cylindrical portion 22 constituting a part of the vibration isolating bush 18 as described above. In this example, both the connecting portions 14 and 14 at both ends are provided with a cylinder. A shaped portion 22 is provided. The cylindrical portion 22 is an axis along the orthogonal direction so that the axial center A of the vibration isolating bush 18 is oriented in a direction orthogonal to the longitudinal direction R of the link member 10 (thickness direction T shown in FIG. 2). It is formed in a cylindrical shape with a heart.

  The arm portion 12 includes a hollow portion 38 that extends over substantially the entire length direction R at the center in the width direction S thereof. Further, flanges 40 projecting on both sides in the thickness direction T are provided at both side edges in the width direction S, and the flange 40 is also continuous with the peripheral edge of the connecting portion 34. In this example, the link body 16 are provided over the entire circumference.

  The link body 16 is formed by joining a first member 42 and a second member 44 formed by press-molding a metal plate, and both members 42 and 44 are formed in the same shape in this example.

  Specifically, as shown in FIG. 4, the cylindrical portion 22 includes a first cylindrical portion 22 a on one axial side of the top portion 32 a with respect to the top portion 32 a of the bulging portion 32, and the other axial direction from the top portion 32 a. And the second cylindrical portion 22b on the side. Moreover, the arm part 12 is comprised by the 1st arm part 12a and the 2nd arm part 12b which are divided into 2 in the said thickness direction T, as shown in FIG. 2, FIG. And the said 1st member 42 is comprised by the 1st cylinder parts 22a and 22a of both ends, and the 1st arm part 12a which connects between them, The 2nd arm part which connects the 2nd cylinder parts 22b and 22b of both ends, and the interval between them The said 2nd member 44 is comprised by 12b.

  Then, the first body 42 and the second member 44 are overlapped, and the overlapping portion 46 is joined by welding or the like, so that the link main body 16 is formed, and the first tubular portion 22a and the second tubular portion 22b form a cylinder. A shaped portion 22 is formed. Further, as shown in FIG. 6, by overlapping the first arm portion 12 a and the second arm portion 12 b, the arm portion 12 including the hollow portion 38 is formed inside the overlapping portion 46, thereby reinforcing However, weight reduction is achieved.

  As shown in FIGS. 2, 4, and 6, the outer surface of the link body 16 is entirely covered with a rubber film 48 that continues from the elastic portion 24 of the vibration isolating bush 18. The rubber film 48 is vulcanized and bonded to the outer surface of the link main body 16, and the thickness thereof is not particularly limited, but is usually formed as a thin film having a thickness of 1 mm or less, in this example, about 0.5 mm.

  When manufacturing the above link member 10, the link main body 16 formed by adhering the first member 42 and the second member 44 and the inner cylinder 20 having the bulging portion 26 to the inner cylinder 20 are the link main body. 16 is placed in a mold (not shown) so as to be surrounded by the cylindrical parts 22 and 22 at both ends, and a rubber material is injected into the mold, whereby the elastic part 24 and the rubber film 48 Is vulcanized. As a result, the elastic portion 24 is integrally vulcanized and bonded to the outer peripheral surface of the inner cylinder 20 and the inner peripheral surface of the cylindrical portion 22. After the elastic portion 24 is integrally vulcanized and formed on the link main body 16 in this way, the link member 10 is obtained by drawing the cylindrical portion 22 in the diameter reducing direction using a die (not shown). . FIG. 7 shows a shape before drawing, and the diameter of the cylindrical portion 22 is reduced as shown by a two-dot chain line by drawing.

  As shown in FIG. 8, the link member 10 having the above structure is a fastening member such as a bolt 2 and a nut 3 in a state where both end surfaces of the inner cylinder 20 are sandwiched between brackets 1 such as a suspension member 68 in the connecting portion 14. The suspension member 68 and the axle 62 are connected to each other by fastening with the bracket 1.

  In the link member 10 of the present embodiment, the bulging portion 32 is provided in the cylindrical portion 22, and the inner peripheral surface thereof is concentric with the convex spherical surface 28 of the bulging portion 26 of the inner cylinder 20. As a result, the force received by the elastic portion 24 interposed between the convex spherical surface 28 and the concave spherical surface 30 is only shear deformation when displaced in the twisting direction Z, so that the spring constant in the twisting direction Z is effective. Can be reduced. As a result, the spring constant in the vertical direction of the suspension device can be reduced, so that riding comfort can be improved.

  Further, at the time of displacement in the axial direction X, as shown in FIG. 5, the elastic portion 24 is subjected not only to shear deformation but also to compression deformation between the convex spherical surface 28 and the concave spherical surface 30. The spring constant can be increased. Thereby, the spring constant in the left-right direction of the suspension device is increased, and the steering stability can be improved. Therefore, both ride comfort and handling stability can be achieved.

  In particular, on the axially outer side X1 of the phantom spherical surface 34, the elastic portion 24 is not filled between the inner cylinder 20 and the cylindrical portion 22, and further, the phantom spherical surface 34 and the elastic portion 24 are not filled. The crossing point J with the both axial end surfaces 25 is positioned closer to the cylindrical portion 22 than the innermost point K in the axial end surface 25, so that the axial direction of the elastic portion 24 during displacement in the twisting direction Z The spring constant in the twisting direction Z can be further reduced by reliably avoiding the compression spring from being applied at the end. Therefore, the spring constant in the vertical direction of the suspension device can be further reduced and the suspension can be made flexible, so that the vertical movement is absorbed by the suspension so as not to change the height of the occupant's eyes. A feeling can be obtained.

  Further, since the outer surface of the link body 16 is covered with a rubber film 48 connected to the elastic portion 24, cationic coating for rust prevention can be omitted, and since the rubber film 48 is used, scattering of gravel and the like is possible. It is hard to be damaged by rust and has excellent rust prevention effect. Further, since the rubber film 48 is also provided when the elastic portion 24 is formed on the link body 16, the rubber film 48 can be formed without increasing the number of manufacturing steps.

  9 to 11 show a link member 50 according to another embodiment. In this example, a dynamic damper 52 is provided on the arm portion 12 of the link body 16. The dynamic damper 52 includes a mass body 54 and an elastic support portion 56 that supports the mass body 54 with respect to the arm portion 12. In this example, the dynamic damper 52 is attached to the flanges 40 on both sides of the arm portion 12. Yes.

  The mass body 54 has an elongated plate shape extending along the longitudinal direction R of the arm portion 12 and is supported by elastic support portions 56 and 56 provided separately at both ends thereof. In this example, the elastic support portion 56 is formed of a rubber-like elastic body that is continuous with the elastic portion 24 and the rubber film 48. As shown in FIG. Covered. Other configurations are the same as those in the above-described embodiment, and a description thereof will be omitted.

  In the present embodiment, as described above, since the elastic portion 24 is directly vulcanized and formed on the link body 16, the dynamic damper 52 can also be formed at the same time. Therefore, the dynamic damper 52 is incorporated without increasing man-hours. be able to.

  In the above embodiment, the link main body 16 is formed by joining the first member 44 having the first cylindrical portion 22a and the second member 44 having the second cylindrical portion 22b to form the cylindrical portion 22. Although comprised, the cylindrical part 22 can also be formed with a single member in the axial direction X.

  Moreover, in the said embodiment, although the anti-vibration bush 18 was provided in the connection parts 14 and 14 of the both ends of the link main body 16, the anti-vibration bush 18 may be formed only in the connection part 14 of one end. In that case, it is preferable to provide the anti-vibration bush 18 on the connecting portion 14 on the suspension member 68 side.

  Moreover, in the said embodiment, in order to make it a bulge type bush, the bulging part 26 provided in the inner cylinder 20 was integrally formed with the metal material, However, The resin-made cyclic | annular covering body is provided in the outer peripheral surface of an inner cylinder, etc. Thus, the bulging portion may be formed.

It is a top view of the link member concerning one embodiment of the present invention. It is the II-II sectional view taken on the line of FIG. It is a principal part enlarged plan view of the link member. It is a principal part expanded sectional view of the link member. It is a principal part expanded sectional view of the vibration proof bush in the link member. It is the VI-VI sectional view taken on the line of FIG. It is principal part sectional drawing before the drawing process of a vibration proof bush. It is principal part sectional drawing which shows the assembly | attachment state of the link member. It is a top view of the link member concerning other embodiments. FIG. 10 is a sectional view taken along line XX in FIG. 9. It is the XI-XI sectional view taken on the line of FIG. It is a perspective view of a suspension device. It is a top view of a suspension apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,50 ... Link member, 12 ... Arm member, 14 ... Connection part, 16 ... Link main body, 18 ... Anti-vibration bush, 20 ... Inner cylinder (shaft member), 22 ... Cylindrical part, 24 ... Elastic part, 25 ... End face in the axial direction of the elastic part, 26 ... bulge part, 28 ... convex spherical surface, 30 ... concave spherical surface, 34 ... virtual spherical surface, 48 ... rubber film, 52 ... dynamic damper, 54 ... mass body, 56 ... elastic support part, J: intersection of the phantom spherical surface and the axial end surface, K: innermost point on the axial end surface, X: axial direction, X1: axially outward side, X2: axially inward side, Y: axially orthogonal direction , Z ... Pinch direction

Claims (6)

A link member comprising: a link main body comprising an arm part and a connecting part provided at both ends of the arm part; and a vibration isolating bush provided in at least one of the connecting parts,
The anti-vibration bush is provided with a shaft member, a cylindrical portion provided in the connecting portion and surrounding the shaft member, and an outer peripheral surface of the shaft member interposed between the shaft member and the cylindrical portion. An elastic portion made of a rubber-like elastic body integrally formed on the inner peripheral surface of the cylindrical portion,
The shaft member has a bulging portion that bulges in a direction perpendicular to the axis at a central portion in the axial direction, and an outer peripheral surface of the bulging portion is formed into a convex spherical surface, and the cylinder surrounding the convex spherical surface A link member, wherein an inner peripheral surface portion of the shaped portion is formed in a concave spherical surface concentric with the convex spherical surface.   The elastic portion is interposed between the convex spherical surface and the concave spherical surface so as not to be filled between the shaft member and the cylindrical portion on the axially outer side of the virtual spherical surface defined by the concave spherical surface. The link member according to claim 1. Both end surfaces in the axial direction of the elastic portion are formed in curved surfaces that swell inward in the axial direction,
In a cross section along the axial direction of the shaft member, a virtual spherical surface defined by the concave spherical surface intersects the curved surface-shaped axial end surface, and an intersection (J) between the virtual spherical surface and the axial end surface is: 3. The link member according to claim 1, wherein the link member is located closer to the cylindrical portion than the innermost point (K) in the axial end surface. 4.   The link member according to any one of claims 1 to 3, wherein the cylindrical portion of the link body is drawn in a reduced diameter direction after forming the elastic portion.   The link member according to any one of claims 1 to 4, wherein an outer surface of the link body is covered with a rubber film continuous from the elastic portion.   The arm portion is provided with a dynamic damper including a mass body and an elastic support portion that supports the mass body with respect to the arm portion, and the elastic support portion is formed of a rubber-like elastic body that is continuous with the elastic portion. The link member according to claim 1, wherein the link member is formed.

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