Cylindrical vibration isolator

Abstract

Provided is a cylindrical vibration isolator of a novel structure that can obtain a long-term stable fixing force by pressing a resin-made outer cylinder member into an assembly hole. A cylindrical vibration isolator (10) is formed by joining an inner shaft member (12) and an outer cylinder member (14) made of synthetic resin with a main body rubber elastic body (16), wherein the main body rubber elastic body (16) has a pair of rubber arms (34, 34) that extend from the inner shaft member (12) to both sides to join the inner shaft member (12) and the outer cylinder member (14) in the radial direction, the outer cylinder member (14) has a circumferential partition portion (28) on the outer peripheral side of the rubber arm (34), a joining rubber (42) that joins both sides of the partition portion (28) in the circumferential direction is provided at the partition portion (28), and a cavity (44) that penetrates in the axial direction on the inner periphery of the joining rubber (42) is formed at the outer peripheral end of the rubber arm (34).

Description

Technical Field

[0001] This invention relates to a cylindrical vibration damping device for use in motor vehicle engine mounts and the like. Background Technology

[0002] Previously, cylindrical vibration damping devices were used in motor vehicles, such as engine mounts, subframe mounts, and suspension bushings. For example, as disclosed in Japanese Patent Application Publication No. 5-126183 (Patent Document 1), the cylindrical vibration damping device has a structure in which an inner shaft member and an outer cylinder member are connected by a main rubber elastomer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 5-126183 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Incidentally, while previous outer cylinder components were made of metal, the use of synthetic resin for outer cylinder components has been studied for purposes such as reducing the weight of cylindrical vibration damping devices. Patent Document 1 also provides an example of an outer cylinder component made of synthetic resin.

[0008] However, if the outer cylinder component pressed into the mounting hole of the installation object is made of synthetic resin, the stress generated by pressing into the mounting hole will continue to act, making the outer cylinder component prone to plastic deformation. There is a risk that the fixing force relative to the installation object will decrease due to the plastic deformation (aging) of the outer cylinder component.

[0009] The problem to be solved by the present invention is to provide a novel cylindrical vibration damping device that can obtain a long-term stable fixing force by pressing a resin outer cylinder component into an assembly hole.

[0010] means for solving problems

[0011] Hereinafter, preferred embodiments for mastering the present invention will be described. However, the embodiments described below are exemplary and can be appropriately combined with each other. Furthermore, the various constituent elements described in each embodiment can be identified and used as independently as possible, and can also be appropriately combined with any constituent element described in other embodiments. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0012] The first method is a cylindrical vibration damping device, which is formed by connecting an inner shaft component and an outer cylinder component made of synthetic resin through a main rubber elastomer. The main rubber elastomer has a pair of rubber arms that extend from the inner shaft component to both sides and connect the inner shaft component and the outer cylinder component in the radial direction. The outer cylinder component has a circumferentially divided portion on the outer periphery of the rubber arm. A connecting rubber is disposed in the divided portion to connect the two sides of the divided portion in the outer cylinder component in the circumferential direction. A cavity is formed at the outer periphery end of the rubber arm that extends axially through the inner periphery of the connecting rubber.

[0013] According to the cylindrical vibration damping device formed in accordance with this method, when the outer cylinder component is pressed into the assembly hole, the connecting rubber disposed in the segment of the outer cylinder component is compressed in the circumferential direction, thereby reducing the stress (pressing reaction force) acting on the outer cylinder component, and obtaining the fixing force generated by pressing in a relatively long-term and stable manner based on the elasticity of the connecting rubber.

[0014] By forming a segment on the outer cylinder component on the outer periphery of the rubber arm that connects the inner shaft component and the outer cylinder component, the rubber arm is less likely to be compressed radially between the inner shaft component and the outer cylinder component when the outer cylinder component is pressed into the assembly hole. The deviation of the fixing force during pressing and the elastic properties of the main rubber elastomer are reduced, thus achieving stable performance.

[0015] By forming a cavity along the inner circumference of the connecting rubber, extending axially through the outer circumferential end of the rubber arm, the connecting rubber is allowed to bulge and deform into the cavity when compressed in the circumferential direction. This effectively utilizes the circumferential elasticity of the connecting rubber, and allows for the effective acquisition of the desired indentation reaction force.

[0016] The second method, based on the cylindrical vibration damping device described in the first method, involves the inner circumferential surface of the connecting rubber forming the inner wall surface of the cavity extending axially in a concave profile toward the inner circumferential opening.

[0017] According to the cylindrical vibration damping device formed in accordance with this method, when the connecting rubber is compressed in the circumferential direction by pressing the outer cylinder member into the assembly hole, the connecting rubber is not prone to deformation toward the inner circumference of the outer cylinder member, and the pressing reaction force based on the circumferential compressive elasticity of the connecting rubber is effectively utilized.

[0018] The third method, based on the cylindrical vibration damping device described in the first or second method, has a maximum circumferential width of the cavity that is greater than the circumferential width of the segment of the outer cylinder component.

[0019] According to the cylindrical vibration damping device formed in accordance with this method, the connecting rubber provided in the segment of the outer cylinder member is allowed to bulge outward and deform in the inner circumferential direction through the cavity, so that the pressing reaction force based on the compressive elasticity of the connecting rubber can be appropriately obtained.

[0020] The fourth method is based on the cylindrical vibration damping device described in any of the first to third methods, wherein the outer cylinder component is formed as a segmented structure consisting of a pair of outer segmented bodies, and a pair of segmented portions are formed between the circumferential ends of the pair of outer segmented bodies, and the pair of segmented portions are disposed on the outer circumferential sides of the pair of rubber arms.

[0021] According to the cylindrical vibration damping device formed in accordance with this method, when the two pairs of segmented parts constituting the outer cylinder member are close to each other, the outer cylinder member is pressed into the assembly hole, thereby utilizing the anti-detachment resistance generated by the compressive elasticity of the connecting rubbers respectively provided in the pair of segmented parts. Therefore, the deformation of the outer cylinder member (stress acting on the outer cylinder member) can be further reduced, and the pressing fixing force based on the elasticity of the connecting rubber can be effectively obtained.

[0022] Invention Effects

[0023] According to the present invention, in the cylindrical vibration damping device, a long-term stable fixing force can be obtained by pressing the outer cylinder component made of synthetic resin into the assembly hole. Attached Figure Description

[0024] Figure 1 This is a perspective view showing the cylindrical vibration damping device as a first embodiment of the present invention.

[0025] Figure 2 yes Figure 1 The front view of the cylindrical vibration damping device shown.

[0026] Figure 3 yes Figure 2 The right view of the cylindrical vibration damping device shown.

[0027] Figure 4 yes Figure 2 Sectional view IV-IV.

[0028] Figure 5 yes Figure 2 VV sectional view.

[0029] Figure 6 yes Figure 3 Sectional view VI-VI.

[0030] Figure 7 It is Figure 1 The cross-sectional view of the cylindrical vibration damping device shown is presented in its assembled state with the retainer, and is equivalent to... Figure 8A diagram of section VII-VII.

[0031] Figure 8 yes Figure 7 Sectional view of VIII-VIII.

[0032] Figure 9 This is a front view of the cylindrical vibration damping device as a second embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 10: Cylindrical vibration damping device (first embodiment); 12: Inner shaft component; 14: Outer cylinder component; 16: Main rubber elastomer; 18: Bolt insertion through hole; 20: Cylindrical part; 22: Flange part; 24: Outer segment; 26: Segment end; 28: Segment; 30: Notched groove; 32: Notched hole; 34: Rubber arm; 36: Inner circumferential cylinder part; 38: Outer circumferential cylinder part; 40: Stop rubber; 42: Connecting rubber; 44: Cavity; 46: Inner circumferential concave surface; 48: Outer circumferential concave surface; 50: Connecting surface; 52: Assembly hole; 54: Retaining member; 60: Cylindrical vibration damping device (second embodiment); 62: Outer cylinder component. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] exist Figures 1-6 The diagram shows a cylindrical vibration damping device 10 as a first embodiment of the present invention. The cylindrical vibration damping device 10 has a structure in which an inner shaft member 12 and an outer cylinder member 14 are connected by a main body rubber elastomer 16. In the following description, in principle, the vertical direction refers to... Figure 2 The up and down directions and the left and right directions refer to... Figure 2 The left and right directions and the front and back directions refer to Figure 3 The left and right directions in the middle.

[0037] The inner shaft member 12 is formed into a generally cylindrical shape with thick walls and a small diameter. The inner shaft member 12 is formed of a metal such as iron. The inner shaft member 12 has a bolt insertion through hole 18 that extends along the axial direction, and is fixed to a mounting object such as a power unit (not shown) by inserting a mounting bolt (not shown) that extends through the bolt insertion through hole 18.

[0038] The outer cylinder component 14 is made of synthetic resin, such as polyamide. The outer cylinder component 14 is formed into a generally cylindrical shape with thin walls and a large diameter, and has a cylindrical part 20 that is generally cylindrical and a flange part 22 that is generally annular plate-shaped and protrudes outward from the front end of the cylindrical part 20.

[0039] In this embodiment, the outer cylinder member 14 is formed as a segmented structure by arranging a pair of outer segmented bodies 24, 24, each formed into a generally semi-cylindrical shape, opposite to each other in the vertical direction. Each outer segmented body 24 integrally includes a semi-circular portion of the cylindrical portion 20 and a semi-circular portion of the flange portion 22. The outer segmented body 24 is formed with segmented end 26 that protrudes inwardly at both ends in the circumferential direction and is formed into a thick wall in the radial direction, and the area of ​​the circumferential end face is formed to be relatively large. In this embodiment, the segmented end 26 is respectively provided at both ends in the circumferential direction of each outer segmented body 24. The outer diameter of the pair of outer cylinder members 14, 24, in the vertical direction (opposite direction) when no external force is applied is larger than the outer diameter in the horizontal direction.

[0040] Furthermore, a dividing portion 28 is formed between the circumferential ends of one pair of outer cylindrical members 24, 24. In other words, the cylindrical outer cylindrical member 14 is divided circumferentially at the dividing portions 28, 28, thereby forming one pair of semi-cylindrical outer cylindrical members 24, 24. It should be noted that the dividing portions 28 extend continuously in a straight line along the entire axial length of the outer cylindrical member 14.

[0041] The outer cylinder member 14 is configured to surround the outer periphery of the inner shaft member 12, and a main rubber elastomer 16 is disposed radially between the inner shaft member 12 and the outer cylinder member 14. The main rubber elastomer 16 is generally cylindrical in shape, with its inner circumferential surface vulcanized and bonded to the outer circumferential surface of the inner shaft member 12, and its outer circumferential surface vulcanized and bonded to the inner circumferential surface of the outer cylinder member 14. More specifically, the inner circumferential surface of the main rubber elastomer 16, which is fixed to the inner shaft member 12, is formed as a generally cylindrical surface, and the outer circumferential surface of the main rubber elastomer 16, which is fixed to the outer cylinder member 14, is formed as a generally elongated cylindrical surface. With the inner shaft member 12 and the outer cylinder member 14 connected by the main rubber elastomer 16, the inner shaft member 12 protrudes axially to both sides relative to the outer cylinder member 14.

[0042] In the main body rubber elastomer 16, annular grooves 30 extending circumferentially are formed with openings at both ends in the axial direction. A pair of through-holes 32, 32 are formed in the main body rubber elastomer 16. The through-holes 32 are formed on both sides of the inner shaft member 12 in the vertical direction and extend in the horizontal direction, with their left and right ends reaching positions further outward than the inner shaft member 12 in the horizontal direction. Both through-holes 32 and 32 are formed with a length shorter than half a circumference in the circumferential direction, and are formed at positions relative to the center of the inner shaft member 12, moving away from both sides in the vertical direction.

[0043] A pair of rubber arms 34 are formed between the upper and lower ends of a pair of recessed holes 32, 32 in the main rubber elastomer 16. These rubber arms 34, 34 extend in the left-right direction and connect the inner shaft member 12 and the outer cylinder member 14 in the left-right direction. The pair of rubber arms 34, 34 are configured to connect the inner circumferential cylinder portion 36, which is fixed to the outer circumferential surface of the inner shaft member 12, and the outer circumferential cylinder portion 38, which is fixed to the inner circumferential surface of the outer cylinder member 14, to each other in the left-right direction. Thus, on the left and right sides of the inner shaft member 12, the inner shaft member 12 and the outer cylinder member 14 are connected in the left-right direction by the pair of rubber arms 34, 34. The pair of rubber arms 34, 34 are arranged in a straight line in the left-right direction, which is the connection direction between the inner shaft member 12 and the outer cylinder member 14, and the elastic main shaft extending in the connection direction extends from the inner shaft member 12 toward the outer cylinder member 14 in the left-right direction. The axial end face of the rubber arm 34 is formed by the bottom surface of the recessed groove 30, and the inner circumferential cylindrical portion 36 and the outer circumferential cylindrical portion 38 protrude axially more than the axial end face of the rubber arm 34.

[0044] A pair of stop rubbers 40, 40 are formed on the main body rubber elastomer 16 at a position on the upper and lower outer sides of a pair of recessed holes 32, 32, protruding from the outer cylinder member 14 toward the inner shaft member 12 on the upper and lower inner sides. The relative displacement of the inner shaft member 12 and the outer cylinder member 14 in the upper and lower directions is limited by the contact between the stop rubbers 40 and the inner shaft member 12.

[0045] The segmented portions 28 of the outer cylinder member 14 are located on the outer periphery of a pair of rubber arms 34, 34. Furthermore, a connecting rubber 42 is disposed on each segmented portion 28. The connecting rubber 42 is integrally formed, protruding outward from the rubber arm 34, and its outer periphery is disposed on the segmented portion 28 of the outer cylinder member 14. The outer periphery of the connecting rubber 42 is fixed to the circumferential end faces of a pair of outer segmented bodies 24, 24 on the inner surfaces of the circumferential sides of the segmented portion 28. The circumferential ends of the pair of outer segmented bodies 24, 24 are respectively connected circumferentially at the segmented portions 28, 28 by the connecting rubber 42, 42. The outer periphery end face of the connecting rubber 42 is located slightly closer to the inner periphery than the outer periphery of the cylindrical portion 20, but does not protrude outward from the outer periphery of the cylindrical portion 20 of the outer cylinder member 14. In this embodiment, the connecting rubber 42 is configured to include not only the outer peripheral portion disposed on the dividing portion 28, but also a portion of the outer peripheral cylindrical portion 38 located on the inner peripheral side of the dividing portion 28 and on the outer peripheral side of the rubber arm 34. The axial length of the connecting rubber 42 is longer than the axial length of the rubber arm 34, and the axial length of the connecting rubber 42 is formed to be approximately the same as the axial length of the outer peripheral cylindrical portion 38.

[0046] A cavity 44 extending axially is formed at the outer peripheral end of the rubber arm 34. The cavity 44 is formed as a hole extending axially with a substantially constant cross-sectional shape and is formed on the inner peripheral side of the connecting rubber 42. Therefore, the cavity 44 is located between the rubber arm 34 and the connecting rubber 42. Figure 6As shown, the inner surface of the peripheral wall of cavity 44 is configured to include: an inner peripheral concave surface 46, which is an arc-shaped curved surface concave towards the outer periphery; an outer peripheral concave surface 48, which is an arc-shaped curved surface concave towards the inner periphery; and connecting surfaces 50, 50, which connect the opening ends of the inner peripheral concave surface 46 and the outer peripheral concave surface 48 to each other. The width of the opening of the inner peripheral concave surface 46 towards the outer periphery is larger than the width of the opening of the outer peripheral concave surface 48 towards the inner periphery, and the opening ends of the inner peripheral concave surface 46 and the outer peripheral concave surface 48 are continuous by connecting surfaces 50, 50 that extend approximately circumferentially. Therefore, the inner and outer peripheral portions of cavity 44 are each formed into approximately semi-circular shapes, with the diameter of the inner peripheral portion being larger than the diameter of the outer peripheral portion. The inner peripheral concave surface 46, the outer peripheral concave surface 48, and the connecting surfaces 50, 50 are formed as a series of smoothly continuous curved surfaces without inflection points or fold lines. In this embodiment, the curvature of the inner circumferential concave surface 46 is formed such that the two outer portions in the vertical direction are smaller than the central portion in the vertical direction. The connecting surface 50 of the cavity 44 forms part of the inner circumferential surface of the outer circumferential cylindrical portion 38, but protrudes slightly inward to the circumference corresponding to the dividing end 26 of the outer dividing body 24.

[0047] The cavity 44 is located on the inner circumferential side of the connecting rubber 42, and the outer circumferential concave surface 48 is aligned circumferentially with respect to the connecting rubber 42. Therefore, the inner circumferential surface of the connecting rubber 42 is formed by the outer circumferential concave surface 48 of the cavity 44, creating a concave curved surface extending axially with a concave cross-section facing the inner circumferential opening. The curvature of the outer circumferential concave surface 48 on the connecting rubber 42 side of the cavity 44 is greater than the curvature of the inner circumferential concave surface 46 on the rubber arm 34 side; therefore, the inner circumferential surface of the connecting rubber 42 is formed as a concave curved surface with greater curvature. It should be noted that the connecting rubber 42 is positioned to protrude to a position axially outer than the rubber arm 34; therefore, the outer circumferential concave surface 48 constituting the inner circumferential surface of the connecting rubber 42 is positioned axially outer than the inner circumferential concave surface 46 (see reference). Figure 1 , Figure 4 ).

[0048] The maximum circumferential width w1 of the cavity 44 is greater than the circumferential width w2 of the segment 28 (the width of the connecting rubber 42). The maximum circumferential width w1 of the cavity 44 is greater than the circumferential width w2 of the segment 28 located on the outer periphery of the cavity 44 in the outer cylinder member 14. In this embodiment, the cavity 44 has a cross-sectional shape that is substantially constant in the axial direction, the maximum width w1 of the cavity 44 is substantially constant in the axial direction, and the segment 28 extends axially with a substantially constant width w2. Therefore, at any position in the axial direction, the maximum width w1 of the cavity 44 is greater than the width w2 of the segment 28. It should be noted that in this embodiment, as... Figure 6 As shown, the maximum width dimension w1 of the cavity 44 is formed as the width dimension of the outer peripheral end of the inner peripheral concave surface 46.

[0049] The outer peripheral surface of the connecting rubber 42 is formed as a roughly flat plane extending orthogonally to the left and right directions, and the curvature of the inner peripheral surface formed by the outer peripheral concave surface 48 is greater than the curvature of the outer peripheral surface. Therefore, the radial thickness of the connecting rubber 42 decreases from the two circumferential ends toward the circumferential center.

[0050] like Figure 7 , Figure 8 As shown, in the cylindrical vibration damping device 10 with such a structure, the outer cylinder member 14 is pressed into an assembly hole 52 provided on a mounting object such as a vehicle body. The assembly hole 52 is, for example, formed by the inner hole of a cylindrical retainer 54, and by pressing the outer cylinder member 14 in, the outer cylinder member 14 is mounted on the mounting object having the retainer 54.

[0051] The outer cylinder component 14 is pressed into the assembly hole 52 in a state where a pair of outer split bodies 24, 24 are brought closer to each other in the vertical direction using a clamp or the like, thereby reducing the maximum outer diameter. When pressed into the assembly hole 52, the outer cylinder component 14 reduces the outer diameter in the vertical direction due to the proximity displacement of the pair of outer split bodies 24, 24, and is formed into a roughly cylindrical shape, with the outer diameter in the vertical direction being approximately the same as the outer diameter in the horizontal direction.

[0052] When a pair of outer segments 24, 24 approach each other in the vertical direction, the connecting rubbers 42, 42 are compressed circumferentially between the circumferential ends of the outer segments 24, 24. As a result, the outer cylinder member 14, pressed into the assembly hole 52, is pressed against the inner surface of the assembly hole 52 based on the elasticity of the compressed connecting rubbers 42, 42, and a resistance to axial dislodgement acts between the outer circumferential surface of the outer cylinder member 14 and the inner surface of the assembly hole 52 (the inner circumferential surface of the retainer 54).

[0053] Since the segmented portions 28, 28 of the outer cylinder member 14 are located on the outer periphery of the rubber arms 34, 34, even if the pair of circumferentially divided bodies 24, 24 at the segmented portions 28, 28 are close to each other, the pair of rubber arms 34, 34 will hardly experience compressive deformation in the connection direction between the inner shaft member 12 and the outer cylinder member 14 (the left-right direction as the extension direction of the rubber arm 34). Therefore, deviations in the pressing and fixing force caused by the elasticity of the rubber arm 34 can be prevented, and the influence on the elastic characteristics of the rubber arm 34 can be reduced.

[0054] When the outer cylinder member 14 is pressed into the assembly hole 52, the two pairs of segmented bodies 24, 24, moving closer to each other from their initial positions before pressing, and on the other hand, hardly undergo elastic deformation caused by external force (pressing reaction force). Therefore, plastic deformation (aging) of the outer cylinder member 14 caused by continuous external force can be suppressed. Even for the outer cylinder member 14 made of synthetic resin, which is more prone to aging problems compared to metal, the reduction in pressing fixing force caused by aging of the outer cylinder member 14 is not a problem. Therefore, according to the cylindrical vibration damping device 10, the fixing force generated by pressing the outer cylinder member 14 into the assembly hole 52 can be utilized for a longer and more stable period of time.

[0055] Furthermore, the fixing force generated by pressing the outer cylinder member 14 into the assembly hole 52 is based on the elasticity of the connecting rubbers 42, 42 compressed circumferentially between the outer split bodies 24, 24. Therefore, the pressing fixing force relative to the assembly hole 52 can be easily adjusted and set according to the shape, size, and forming material of the connecting rubbers 42. The connecting rubbers 42 are separated from the rubber arm 34 by the cavity 44, which hardly affects the elastic characteristics of the main rubber elastomer 16 or even the vibration damping performance of the cylindrical vibration damping device 10. Therefore, the shape and size can be designed with a large degree of freedom, and the pressing fixing force can be set with high precision within a large adjustment range.

[0056] By forming the circumferential end of the outer segment 24 into a thick-walled segment end 26, the area (radial width dimension) of the circumferential end face of the outer segment 24 that is used to fix the connecting rubber 42 is increased. As a result, the size of the portion of the connecting rubber 42 that is compressed between the circumferential end faces of the outer segments 24 can be ensured, and the pressing and fixing force generated by the elasticity of the connecting rubber 42 can be adjusted.

[0057] By forming a cavity 44 on the inner circumferential side of the connecting rubber 42, the cavity 44 allows the connecting rubber 42 to bulge outwards when it is compressed in the circumferential direction. This prevents significant hardening of the circumferential elasticity of the connecting rubber 42 or the bulging deformation of the connecting rubber 42 inwards from affecting the elastic properties of the rubber arm 34. Furthermore, by allowing the connecting rubber 42 to deform inwards, it prevents the connecting rubber 42 from bulging outwards due to circumferential compression, thus preventing the connecting rubber 42 from protruding further outwards than the outer circumferential surface of the outer cylinder member 14 and hindering its insertion into the assembly hole 52.

[0058] In this embodiment, since the circumferential width of the cavity 44 is larger than that of the connecting rubber 42, the connecting rubber 42 is allowed to deform inwards. It should be noted that since the connecting rubber 42 protrudes further outwards axially than the rubber arms 34, the axial ends of the connecting rubber 42 are located further outwards axially than the cavity 44. However, there are no rubber arms 34 on the inner circumference of the axial ends of the connecting rubber 42, and the notch 30 allows for inward deformation of the axial ends of the connecting rubber 42.

[0059] The inner circumferential surface of the connecting rubber 42 is formed by a concave curved surface (outer circumferential concave surface 48) opening inward. The cavity 44 and the notch 30 allow for deformation of the connecting rubber 42 towards the inner circumferential side, while the arched shape of the inner circumferential portion of the connecting rubber 42 limits excessive deformation towards the inner circumferential side. Therefore, the circumferential elasticity of the connecting rubber 42 can be appropriately adjusted, and the pressing and fixing force of the outer cylinder member 14 relative to the assembly hole 52 can be effectively obtained. It should be noted that the size of the outer circumferential concave surface 48, which is convex outward, is not limited, but preferably the circumferential width dimension w3 is 0.5*w2≤w3≤2*w2. Furthermore, from... Figure 6 It is understood that a narrow portion with a small rubber thickness is formed between the connecting rubber 42 and the outer peripheral cylinder 38, between the inner peripheral edge of the circumferential end face of the outer segment 24 (in this embodiment, the part forming the segment end 26) and the outer peripheral concave surface 48 of the cavity 44. Therefore, it is possible to more effectively suppress the adverse effects of the compressive strain and stress of the connecting rubber 42 on the rubber arm 34 side caused by the pressing of the outer cylinder member 14 into the assembly hole 52.

[0060] A cavity 44 with an inner concave surface 46 is formed at the outer peripheral end of the rubber arm 34, thereby forming a shape in which the outer peripheral end of the rubber arm 34 branches into two strands circumferentially to both sides of the cavity 44. Thus, the elastic characteristics of the cylindrical vibration damping device 10 are adjusted using the cavity 44. It should be noted that the maximum circumferential width w1 of the cavity 44 is not limited. For example, when ensuring elastic rigidity in the left-right direction using a pair of rubber arms 34, 34, it is preferable that the circumferential dimension of the rubber arm 34 at the location where the cavity 44 is formed is 1 / 3 or less. Furthermore, the radial dimension of the cavity 44 is also preferably 1 / 3 or less relative to the radial dimension of the rubber arm 34.

[0061] Figure 9 A cylindrical vibration damping device 60, representing a second embodiment of the present invention, is shown. The cylindrical vibration damping device 60 is configured such that the inner shaft member 12 and the outer cylinder member 62 are connected by a main body rubber elastomer 16. In the description of this embodiment, components and parts substantially the same as those in the first embodiment are labeled with the same reference numerals in the figures, and descriptions are omitted.

[0062] The outer cylinder member 62 is generally formed into a C-shaped cylinder, with only one segment 28 in a circumferential part. Therefore, the cylindrical part 20, which is formed into a generally cylindrical shape, and the flange part 22, which is formed into a generally annular plate shape, are divided circumferentially at a certain point in the circumferential direction.

[0063] The segment 28 is located on one side of the rubber arm 34 ( Figure 9 On the outer periphery of the right rubber arm 34, a connecting rubber 42 is provided on the outer periphery of one rubber arm 34, while no connecting rubber is provided on the outer periphery of the other rubber arm 34. In addition, the cavity 44 is only formed at the outer periphery end of one rubber arm 34.

[0064] The cylindrical vibration damping device 60, which has such a C-shaped outer cylinder member 62, can also achieve the same effect as the first embodiment described above. That is, when the outer cylinder member 62 is inserted into the assembly hole (52) (not shown), the connecting rubber 42 disposed in the dividing part 28 is compressed in the circumferential direction, thereby reducing the stress acting on the outer cylinder member 62, and the elasticity of the connecting rubber 42 can effectively obtain the fixing force (anti-detachment resistance) of the outer cylinder member 62 relative to the assembly hole (52).

[0065] As shown in this embodiment, the outer cylinder component is not necessarily limited to a segmented structure consisting of a pair of separate segments. The segmented portion of the outer cylinder component can be provided on the outer periphery of at least one of the pair of rubber arms.

[0066] The embodiments of the present invention have been described in detail above, but the present invention is not limited to this specific description. For example, the shape of the cavity 44 is not limited by the specific description of the first embodiment above; for example, it may be a simple circular hole, or a hole cross-sectional shape that extends in the circumferential direction with a predetermined length. In addition, the cross-sectional shape and size of the cavity 44 may also vary in the axial direction.

[0067] The width dimension of the connecting rubber 42 in the circumferential direction, in other words, the width dimension of the segment 28, does not need to be constant in the axial direction and can vary in the axial direction. It should be noted that when at least one of the width dimension of the connecting rubber 42 and the maximum width dimension of the cavity 44 varies in the axial direction, it is preferable that the maximum width dimension of the cavity 44 is greater than the width dimension of the connecting rubber 42, regardless of where the comparison is made in the axial direction.

Claims

1. A cylindrical vibration damping device (10, 60), wherein the cylindrical vibration damping device (10, 60) is formed by connecting an inner shaft component (12) to an outer cylinder component (14, 62) made of synthetic resin through a main body rubber elastomer (16), wherein, The main body rubber elastomer (16) has a pair of rubber arms (34, 34) that extend from the inner shaft member (12) to both sides to connect the inner shaft member (12) and the outer cylinder members (14, 62) in the radial direction. The outer cylinder component (14, 62) has a circumferentially divided portion (28) on the outer periphery of the rubber arm (34). The segment (28) is provided with a connecting rubber (42) that connects the two sides of the segment (28) in the outer cylinder component (14, 62) in the circumferential direction. A cavity (44) is formed at the outer peripheral end of the rubber arm (34) and extends axially through the inner periphery of the connecting rubber (42). The segment (28) extends continuously and in a straight line along the entire axial length of the outer cylinder member (14, 62).

2. The cylindrical vibration damping device (10, 60) according to claim 1, wherein, The inner circumferential surface of the connecting rubber (42) that forms the inner wall surface of the cavity (44) extends axially with a concave profile toward the inner circumferential opening.

3. The cylindrical vibration damping device (10, 60) according to claim 1 or 2, wherein, The maximum circumferential width of the cavity (44) is greater than the circumferential width of the segment (28) of the outer cylinder component (14, 62).

4. The cylindrical vibration damping device (10) according to claim 1 or 2, wherein, The outer cylinder component (14) is formed as a segmented structure consisting of a pair of outer segmented bodies (24, 24). A pair of the aforementioned dividing portions (28) are formed between the circumferential ends of the outer dividing bodies (24, 24). The pair of segmented portions (28) are disposed on the outer periphery of each of the pair of rubber arms (34, 34).

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