JP2024043676A - Cylindrical vibration isolation device - Google Patents

Abstract

[Problem] To provide a cylindrical vibration-isolating device of a new structure that can obtain a stable fixing force for a long time by press-fitting a resin outer tubular member into a mounting hole. [Solution] A cylindrical vibration-isolating device 10 having a structure in which an inner shaft member 12 and an outer tubular member 14 made of synthetic resin are connected by a main rubber elastic body 16, the main rubber elastic body 16 has a pair of rubber arms 34, 34 that extend on both sides from the inner shaft member 12 and connect the inner shaft member 12 and the outer tubular member 14 in the radial direction, the outer tubular member 14 has a circumferential division section 28 on the outer periphery side of the rubber arms 34, the division section 28 has a connecting rubber 42 arranged to connect both sides of the division section 28 in the circumferential direction, and a void 44 is formed at the outer periphery end of the rubber arm 34, penetrating the inner periphery of the connecting rubber 42 in the axial direction. [Selected Figure] Figure 2

Description

The present invention relates to a cylindrical vibration isolation device that is used for automobile engine mounts, etc.

Conventionally, cylindrical vibration isolators have been employed as engine mounts, subframe mounts, suspension bushes, etc. of automobiles. The cylindrical vibration isolator has a structure in which an inner shaft member and an outer cylindrical member are connected by a main body rubber elastic body, as disclosed in, for example, JP-A-5-126183 (Patent Document 1). ing.

Japanese Patent Application Laid-Open No. 5-126183

Conventionally, outer cylindrical members have been made of metal, but in order to reduce the weight of cylindrical vibration-damping devices, the use of synthetic resin outer cylindrical members is being considered. Patent Document 1 also gives an example of an outer cylindrical member made of synthetic resin.

However, if the outer cylindrical member that is press-fitted into the mounting hole of the object to be mounted is made of synthetic resin, the outer cylindrical member is likely to be plastically deformed due to the continuous stress caused by the press-fitting into the mounting hole. There was a risk that the fixing force to the object to be attached would decrease due to plastic deformation (settling).

An object of the present invention is to provide a cylindrical vibration isolator with a novel structure that can obtain stable fixing force over a long period of time by press-fitting a resin outer cylindrical member into a mounting hole. .

The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is merely an example, and may be combined with one another as appropriate. The multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various alternative embodiments may be realized.

The first aspect is a cylindrical vibration-damping device in which an inner shaft member and an outer tubular member made of synthetic resin are connected by a main rubber elastic body, and the main rubber elastic body has a pair of rubber arms that extend out on both sides from the inner shaft member and connect the inner shaft member and the outer tubular member in the radial direction, and the outer tubular member has a circumferential division on the outer periphery of the rubber arms, and a connecting rubber is arranged in the division to connect both sides of the division in the outer tubular member in the circumferential direction, and a void is formed at the outer periphery end of the rubber arms that penetrates the inner periphery of the connecting rubber in the axial direction.

With a cylindrical vibration-damping device constructed according to this embodiment, when the outer tubular member is pressed into the mounting hole, the connecting rubber arranged in the divided portion of the outer tubular member is compressed in the circumferential direction, thereby reducing the stress (press-in reaction force) acting on the outer tubular member, and the fixing force due to the press-in can be obtained stably over a relatively long period of time based on the elasticity of the connecting rubber.

The divided portion of the outer cylinder member is formed on the outer circumferential side of the rubber arm that connects the inner shaft member and the outer cylinder member, so that when the outer cylinder member is press-fitted into the mounting hole, the rubber arm connects the inner shaft member and the outer cylinder. It is difficult to be compressed in the radial direction between the members, and variations in the fixing force during press-fitting and the spring characteristics of the main rubber elastic body are reduced, so stable performance can be achieved.

Since a cavity is formed on the inner circumference of the connecting rubber that passes through the outer peripheral end of the rubber arm in the axial direction, when the connecting rubber is compressed in the circumferential direction, the connecting rubber bulges into the cavity. is allowed. Thereby, the elasticity of the connecting rubber in the circumferential direction is effectively exhibited, and the desired press-in reaction force can be effectively obtained by the elasticity of the connecting rubber.

In the second aspect, in the cylindrical vibration-damping device described in the first aspect, the inner peripheral surface of the connecting rubber that constitutes the inner wall surface of the cavity extends in the axial direction with a concave cross section that opens toward the inner circumference.

According to the cylindrical vibration isolator having the structure according to this aspect, when the connecting rubber is compressed in the circumferential direction by press fitting into the mounting hole of the outer cylindrical member, the connecting rubber is directed toward the inner periphery of the outer cylindrical member. This makes it difficult for deformation to occur, and the press-fit reaction force based on the compression spring in the circumferential direction of the connecting rubber can be effectively exerted.

The third aspect is a cylindrical vibration-damping device according to the first or second aspect, in which the maximum circumferential width of the cavity is greater than the circumferential width of the divided portion of the outer cylindrical member.

According to the cylindrical vibration isolator having the structure according to the present aspect, the connecting rubber provided in the divided portion of the outer cylindrical member is allowed to bulge and deform toward the inner circumferential side throughout the circumferential direction by the space. From this, it is possible to appropriately obtain a press-fitting reaction force based on the compression spring of the connecting rubber.

The fourth aspect is a cylindrical vibration-damping device according to any one of the first to third aspects, in which the outer cylindrical member is a divided structure made up of a pair of outer divided bodies, a pair of divided parts are formed between the circumferential ends of the pair of outer divided bodies, and the pair of divided parts are provided on the outer periphery of each of the pair of rubber arms.

According to the cylindrical vibration isolator having the structure according to the present aspect, the outer cylindrical member is press-fitted into the mounting hole with the pair of outer divided bodies constituting the outer cylindrical member being close to each other. The compression spring of the connecting rubber provided in each divided portion exerts a pull-out resistance force. Therefore, the press-fit fixing force based on the elasticity of the connecting rubber can be effectively obtained while further reducing the deformation of the outer cylindrical member (the stress acting on the outer cylindrical member).

According to the present invention, in the cylindrical vibration isolator, stable fixing force can be obtained over a long period of time by press-fitting the outer cylindrical member made of synthetic resin into the mounting hole.

FIG. 1 is a perspective view showing a cylindrical vibration isolator according to a first embodiment of the present invention; FIG. 2 is a front view of the cylindrical vibration isolator shown in FIG. FIG. 3 is a right side view of the cylindrical vibration isolator shown in FIG. IV-IV cross-sectional view of FIG. VV sectional view in Figure 2 VI-VI cross-sectional view of FIG. 9 is a cross-sectional view showing the cylindrical vibration isolator shown in FIG. 1 in a state where it is attached to a holder, and corresponds to the VII-VII cross section in FIG. 8. VIII-VIII sectional view in Figure 7 A front view showing a cylindrical vibration isolator as a second embodiment of the present invention

The following describes an embodiment of the present invention with reference to the drawings.

1 to 6 show a cylindrical vibration isolator 10 as a first embodiment of the present invention. The cylindrical vibration isolator 10 has a structure in which an inner shaft member 12 and an outer cylindrical member 14 are connected by a main body rubber elastic body 16. In the following description, as a general rule, the vertical direction refers to the vertical direction in FIG. 2, the left-right direction refers to the left-right direction in FIG. 2, and the front-back direction refers to the left-right direction in FIG. 3.

The inner shaft member 12 is thick-walled and has a small diameter, generally cylindrical shape. The inner shaft member 12 is formed of a metal such as iron. The inner shaft member 12 has a bolt insertion hole 18 that penetrates it in the axial direction, and is fixed to an attachment object such as a power unit (not shown) by an attachment bolt (not shown) that is inserted into the bolt insertion hole 18.

The outer cylindrical member 14 is made of synthetic resin, such as polyamide. The outer cylindrical member 14 has a substantially cylindrical shape with a thin wall and a large diameter, and includes a cylindrical portion 20 having a cylindrical shape as a whole and an annular plate shape as a whole that protrudes from the front end of the cylindrical portion 20 to the outer periphery. A flange portion 22 is provided.

The outer cylindrical member 14 of this embodiment is a divided structure in which a pair of outer divided bodies 24, 24 each having a substantially semi-cylindrical shape are arranged facing each other in the vertical direction. . Each outer divided body 24 integrally includes a half circumferential portion of the cylindrical portion 20 and a half circumferential portion of the flange portion 22. The outer divided body 24 has a divided end portion 26 having a thick wall in the radial direction, with both end portions in the circumferential direction protruding toward the inner circumferential side, and the area of the circumferential end surface is increased. In this embodiment, the divided end portions 26 are provided at both ends of each outer divided body 24 in the circumferential direction. The outer cylindrical member 14 on which no external force is applied has an outer diameter dimension in the up-down direction, which is the opposing direction of the pair of outer divided bodies 24, 24, which is larger than an outer diameter dimension in the left-right direction.

A split portion 28 is formed between the circumferential ends of the pair of outer divided bodies 24, 24 of the outer tubular member 14. In other words, the cylindrical outer tubular member 14 is split in the circumferential direction at the split portions 28, 28, thereby forming a pair of semi-cylindrical outer divided bodies 24, 24. The split portion 28 extends linearly and continuously over the entire axial length of the outer tubular member 14.

The outer tubular member 14 is disposed so as to surround the outer periphery of the inner tubular member 12, and a main rubber elastic body 16 is provided between the inner tubular member 12 and the outer tubular member 14 in the radial direction. The main rubber elastic body 16 is generally cylindrical in shape, with its inner circumferential surface vulcanized and bonded to the outer circumferential surface of the inner tubular member 12, and its outer circumferential surface vulcanized and bonded to the inner circumferential surface of the outer tubular member 14. More specifically, the main rubber elastic body 16 has an inner circumferential surface that is fixed to the inner tubular member 12 that is a substantially cylindrical surface, and an outer circumferential surface that is fixed to the outer tubular member 14 that is a substantially elongated cylindrical surface. When the inner tubular member 12 and the outer tubular member 14 are connected by the main rubber elastic body 16, the inner tubular member 12 protrudes on both axial sides relative to the outer tubular member 14.

The main rubber elastic body 16 has a circumferentially extending circular recess groove 30 that opens onto both axial end faces. The main rubber elastic body 16 has a pair of recess holes 32, 32 that penetrate in the axial direction. The recess holes 32 are formed on both vertical sides of the inner shaft member 12 and extend in the left-right direction, with both left and right ends reaching outside the inner shaft member 12 in the left-right direction. The recess holes 32, 32 each have a length shorter than half the circumference in the circumferential direction, and are formed at positions offset to both vertical sides of the center of the inner shaft member 12.

A pair of rubber arms 34, 34 extending in the left-right direction and connecting the inner shaft member 12 and the outer cylinder member 14 in the left-right direction are formed between the upper and lower portions of the pair of hollow holes 32, 32 in the main rubber elastic body 16. ing. The pair of rubber arms 34, 34 mutually move the inner circumferential cylinder part 36 fixed to the outer circumferential surface of the inner shaft member 12 and the outer circumferential cylinder part 38 fixed to the inner circumferential surface of the outer cylinder member 14 in the left-right direction. It is designed to be connected to. As a result, 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 on both left and right sides of the inner shaft member 12. The pair of rubber arms 34 , 34 are arranged in series 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 to the outer cylinder member 14 . It extends to both sides in the left and right direction. The axial end surface of the rubber arm 34 is constituted by the bottom surface of the countersunk groove 30, and the inner circumferential cylindrical portion 36 and the outer circumferential cylindrical portion 38 protrude in the axial direction from the axial end surface of the rubber arm 34.

A pair of stopper rubbers 40, 40 are formed on the outer side of the pair of recessed holes 32, 32 in the main rubber elastic body 16, protruding inward from the outer tubular member 14 toward the inner axial member 12. The amount of relative displacement between the inner axial member 12 and the outer tubular member 14 in the vertical direction is limited by the contact between the stopper rubbers 40 and the inner axial member 12.

The outer circumferential side of the pair of rubber arms 34, 34 is located at each of the divided parts 28 of the outer tubular member 14. A connecting rubber 42 is disposed in each divided part 28. The connecting rubber 42 is integrally formed protruding from the rubber arm 34 to the outer circumferential side, and the outer circumferential part is disposed in the divided part 28 of the outer tubular member 14. The outer circumferential part of the connecting rubber 42 is fixed to the circumferential end faces of the pair of outer divided bodies 24, 24 that constitute the inner surfaces on both circumferential sides of the divided part 28, and the circumferential ends of the pair of outer divided bodies 24, 24 are connected in the circumferential direction by the connecting rubber 42, 42 at the divided parts 28, 28. The connecting rubber 42 does not protrude outward from the tubular part 20 of the outer tubular member 14, and the outer circumferential end face is located slightly inward from the outer circumferential surface of the tubular part 20. In this embodiment, the connecting rubber 42 is configured to include not only the outer peripheral portion disposed in the dividing portion 28, but also a part of the outer peripheral tube 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 connecting rubber 42 has an axial length longer than the rubber arm 34, and has approximately the same axial length as the outer peripheral tube portion 38.

A void 44 is formed at the outer peripheral end of the rubber arm 34, penetrating in the axial direction. The void 44 is a hole-like shape penetrating in the axial direction with a substantially constant cross-sectional shape, and is formed on the inner peripheral side of the connecting rubber 42. Therefore, the void 44 is located between the rubber arm 34 and the connecting rubber 42. As shown in FIG. 6, the void 44 is configured to include an inner peripheral concave surface 46, which is a concave arc-shaped curved surface on the inner peripheral inner wall, an outer peripheral concave surface 48, which is a concave arc-shaped curved surface on the inner peripheral, and connecting surfaces 50, 50 that connect the opening end of the inner peripheral concave surface 46 and the opening end of the outer peripheral concave surface 48 to each other. The width dimension of the opening of the inner peripheral concave surface 46 toward the outer periphery is larger than the width dimension of the opening of the outer peripheral concave surface 48 toward the inner periphery, and the opening end of the inner peripheral concave surface 46 and the opening end of the outer peripheral concave surface 48 are continuous by the connecting surfaces 50, 50 that extend in the substantially circumferential direction. Therefore, the inner and outer circumferential portions of the cavity 44 are each approximately semicircular, with the inner circumferential portion having a larger diameter than the outer circumferential portion. The inner circumferential concave surface 46, the outer circumferential concave surface 48, and the connecting surfaces 50, 50 are a series of smoothly continuous curved surfaces without any bends or lines. The curvature of the inner circumferential concave surface 46 in this embodiment is smaller in both vertical outer portions than in the vertical center portion. The connecting surface 50 of the cavity 44 constitutes part of the inner circumferential surface of the outer circumferential cylindrical portion 38, but protrudes slightly inward to correspond to the divided end portion 26 of the outer divided body 24.

The space 44 is located on the inner peripheral side of the connecting rubber 42, and the outer circumferential concave surface 48 is aligned with the connecting rubber 42 in the circumferential direction. Therefore, the inner circumferential surface of the connecting rubber 42 is constituted by an outer circumferential concave surface 48 of the cavity 44, and is a concave curved surface extending in the axial direction with a concave cross section opening toward the inner circumference. The curvature of the outer circumferential concave surface 48 on the side of the connecting rubber 42 is made larger than the curvature of the inner circumferential concave surface 46 on the rubber arm 34 side, so that the inner circumferential surface of the connecting rubber 42 has a higher curvature. It is said to have a large concave curved surface. Note that since the connecting rubber 42 is provided so as to protrude further outward in the axial direction than the rubber arms 34, the outer circumferential concave surface 48 constituting the inner circumferential surface of the connecting rubber 42 is further axially disposed than the inner circumferential concave surface 46. It is provided to the outside in the direction (see FIGS. 1 and 4).

The maximum width dimension w1 of the void 44 in the circumferential direction is larger than the width dimension w2 of the dividing portion 28 in the circumferential direction (the width dimension of the connecting rubber 42). The maximum width dimension w1 of the void 44 in the circumferential direction is larger than the circumferential width dimension w2 of the dividing portion 28 located on the outer peripheral side of the void 44 in the outer tubular member 14. In this embodiment, the void 44 has a substantially constant cross-sectional shape in the axial direction, the maximum width dimension w1 of the void 44 is substantially constant in the axial direction, and the dividing portion 28 extends in the axial direction with a substantially constant width dimension w2. Therefore, the maximum width dimension w1 of the void 44 is larger than the width dimension w2 of the dividing portion 28 at any position in the axial direction. In this embodiment, the maximum width dimension w1 of the void 44 is the width dimension at the outer peripheral end of the inner peripheral concave surface 46, as shown in FIG. 6.

The outer circumferential surface of the connecting rubber 42 is a substantially flat surface extending orthogonally to the left-right direction, and the curvature of the inner circumferential surface formed by the outer circumferential concave surface 48 is greater than the curvature of the outer circumferential surface. Therefore, the radial thickness dimension of the connecting rubber 42 becomes smaller from both ends in the circumferential direction toward the center in the circumferential direction.

In the cylindrical vibration isolator 10 having such a structure, as shown in FIGS. 7 and 8, the outer cylindrical member 14 is press-fitted into a mounting hole 52 provided in a mounting target such as a vehicle body. The mounting hole 52 is constituted by, for example, an inner hole of a cylindrical holder 54, and the outer cylinder member 14 is press-fitted into the mounting hole 52, so that the outer cylinder member 14 is attached to an object to which the holder 54 is attached.

The outer cylindrical member 14 is press-fitted into the mounting hole 52 with the pair of outer divided bodies 24, 24 brought close to each other in the vertical direction using a jig or the like to reduce the maximum outer diameter. The outer cylindrical member 14 when press-fitted into the mounting hole 52 has a generally cylindrical shape as a whole, with the outer diameter dimension in the vertical direction being reduced by the approaching displacement of the pair of outer divided bodies 24, 24. The outer diameter dimension in the up-down direction and the outer diameter dimension in the left-right direction are approximately the same.

When the pair of outer divided bodies 24, 24 approach each other in the vertical direction, the connecting rubber 42, 42 is compressed in the circumferential direction between the circumferential ends of the pair of outer divided bodies 24, 24. As a result, the outer tubular member 14 pressed into the mounting hole 52 is pressed against the inner wall surface of the mounting hole 52 based on the elasticity of the compressed connecting rubber 42, 42, and a resistance force against axial slippage acts between the outer peripheral surface of the outer tubular member 14 and the inner wall surface of the mounting hole 52 (the inner peripheral surface of the holder 54).

The split parts 28, 28 of the outer tubular member 14 are located on the outer peripheral side of the rubber arms 34, 34. Therefore, even if the pair of outer split bodies 24, 24 split in the circumferential direction at the split parts 28, 28 approach each other, the pair of rubber arms 34, 34 hardly undergoes compressive deformation in the connection direction between the inner shaft member 12 and the outer tubular member 14 (the left-right direction in which the rubber arms 34 extend). This prevents variation in the press-fit fixing force due to the elasticity of the rubber arms 34, and reduces the effect on the spring characteristics of the rubber arms 34.

The pair of outer divided bodies 24, 24 constituting the outer cylindrical member 14 are displaced toward each other from the initial position before press-fitting when they are press-fitted into the mounting hole 52. ) almost no elastic deformation occurs. Therefore, plastic deformation (settling) of the outer cylindrical member 14 due to the action of continuous external force is suppressed, and the outer cylindrical member 14 is made of synthetic resin, which is more likely to suffer from sagging than metal. Also, a decrease in the press-fitting fixing force due to the settling of the outer cylindrical member 14 is less likely to be a problem. Therefore, according to the cylindrical vibration isolator 10, the fixing force generated by press-fitting the outer cylindrical member 14 into the mounting hole 52 can be stably exerted over a longer period of time.

The fixing force exerted by pressing the outer tubular member 14 into the mounting hole 52 is based on the elasticity of the connecting rubber 42, 42 compressed circumferentially between the pair of outer divided bodies 24, 24, so the pressing force for the mounting hole 52 can be easily adjusted and set by the shape, size, and material of the connecting rubber 42. The connecting rubber 42 is separated from the rubber arm 34 by a space 44, and has almost no effect on the spring characteristics of the main rubber elastic body 16, and therefore on 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 force can be set with precision over a wide adjustment range.

The circumferential end of the outer divided body 24 is made into a thick divided end 26, so that the area (radial width dimension) of the circumferential end face of the outer divided body 24 to which the connecting rubber 42 is fixed is increased. This ensures the size of the portion of the connecting rubber 42 that is compressed between the circumferential end faces of the outer divided bodies 24, 24, and makes it possible to adjust the pressing and fixing force due to the elasticity of the connecting rubber 42.

Since the space 44 is formed on the inner circumferential side of the connecting rubber 42, when the connecting rubber 42 is compressed in the circumferential direction, the space 44 allows the connecting rubber 42 to bulge and deform inward. has been done. This can prevent the spring of the connecting rubber 42 from becoming extremely hard in the circumferential direction and preventing the bulging deformation of the connecting rubber 42 toward the inner circumferential side from affecting the spring characteristics of the rubber arm 34. Furthermore, since the connecting rubber 42 is allowed to deform inward, it is difficult for the connecting rubber 42 to bulge outward due to compression in the circumferential direction. It can be prevented from protruding further to the outer periphery and interfering with press-fitting into the mounting hole 52.

In this embodiment, since the circumferential width of the space 44 is larger than the circumferential width of the connecting rubber 42, the entire connecting rubber 42 is allowed to deform inward. Note that since the connecting rubber 42 protrudes further outward in the axial direction than the rubber arms 34, both ends of the connecting rubber 42 in the axial direction are located outside the space 44 in the axial direction. There is no rubber arm 34 on the inner periphery of both end portions, and deformation of the connecting rubber 42 toward the inner periphery of both axial end portions is allowed by the countersunk grooves 30.

The inner circumferential surface of the connecting rubber 42 is constituted by a concave curved surface (outer circumferential concave surface 48) that opens toward the inner circumference, and the hollow space 44 and the groove 30 allow the connecting rubber 42 to deform toward the inner circumference. The arch shape of the inner peripheral portion of the connecting rubber 42 restricts excessive deformation toward the inner peripheral side. As a result, the circumferential spring of the connecting rubber 42 is appropriately adjusted, and a force for press-fitting the outer cylinder member 14 into the mounting hole 52 can be effectively obtained. Although the size of the outer peripheral concave surface 48 that is convex toward the outer peripheral side in the space 44 is not limited, it is preferable that the width w3 in the circumferential direction is 0.5*w2≦w3≦2*w2. be done. Further, as can be understood from FIG. 6, between the connecting rubber 42 and the outer circumferential cylinder part 38, there is an inner edge part of the circumferential end surface of the outer divided body 24 (in this embodiment, the formation of the divided end part 26). Since a constricted portion with a reduced rubber thickness is formed between the outer circumferential concave surface 48 of the hollow space 44, the connecting rubber 42 is compressed when the outer cylinder member 14 is press-fitted into the mounting hole 52. The adverse effects of compressive strain and stress on the rubber arm 34 side can be more effectively suppressed.

Since the cavity 44 having the inner circumferential concave surface 46 is formed at the outer peripheral end of the rubber arm 34, the outer peripheral end of the rubber arm 34 is bifurcated to both sides in the circumferential direction of the cavity 44. ing. Thereby, the spring characteristics of the cylindrical vibration isolator 10 are adjusted using the space 44. Note that the maximum width w1 of the space 44 in the circumferential direction is not limited, but for example, when securing spring rigidity in the left and right direction by the pair of rubber arms 34, 34, the width w1 of the space 44 is It is desirable that the size is 1/3 or less of the circumferential dimension of the arm 34. Further, the radial size of the space 44 is also desirably 1/3 or less of the radial size of the rubber arm 34.

FIG. 9 shows a cylindrical vibration isolator 60 as a second embodiment of the present invention. The cylindrical vibration isolator 60 has a structure in which an inner shaft member 12 and an outer cylindrical member 62 are connected by a main rubber elastic body 16. In the description of this embodiment, substantially the same members and parts as those in the first embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted.

The outer tubular member 62 is generally C-shaped and has only one dividing section 28 at a portion in the circumferential direction. Therefore, the tubular section 20, which is generally cylindrical, and the flange section 22, which is generally annular, are divided in the circumferential direction at one point in the circumferential direction.

The dividing portion 28 is located on the outer periphery of one of the rubber arms 34 (the rubber arm 34 on the right in FIG. 9), and a connecting rubber 42 is provided on the outer periphery of one of the rubber arms 34, while no connecting rubber is provided on the outer periphery of the other rubber arm 34. Also, the void 44 is formed only on the outer periphery end of one of the rubber arms 34.

The same effects as in the first embodiment can also be obtained by the cylindrical vibration isolator 60 including such a C-shaped outer cylindrical member 62. That is, when the outer cylindrical member 62 is inserted into the mounting hole (52) (not shown), the connecting rubber 42 arranged in the divided portion 28 is compressed in the circumferential direction, so that the stress acting on the outer cylindrical member 62 is reduced. It is possible to effectively obtain a force for fixing the outer cylinder member 62 to the mounting hole (52) (resistance to pulling out) by the elasticity of the connecting rubber 42 while reducing the force.

As shown in this embodiment, the outer tubular member is not necessarily limited to a split structure consisting of a pair of outer split bodies, and the split portion of the outer tubular member may be provided on the outer periphery of at least one of the pair of rubber arms.

Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the specific description. For example, the shape of the void 44 is not limited to the specific description of the first embodiment, and may be, for example, a simple circular hole or a hole cross-sectional shape that extends a predetermined length in the circumferential direction. In addition, the cross-sectional shape and size of the void 44 may change in the axial direction.

The width dimension of the connecting rubber 42 in the circumferential direction, in other words, the width dimension of the divided portion 28, does not need to be constant in the axial direction, and may vary in the axial direction. Note that if at least one of the width dimension of the connecting rubber 42 and the maximum width dimension of the void space 44 changes in the axial direction, the maximum width dimension of the void space 44 will not change at any position in the axial direction. It is desirable that the width is larger than the width of the connecting rubber 42.

10 Cylindrical vibration isolation device (first embodiment)
12 Inner shaft member 14 Outer cylindrical member 16 Main rubber elastic body 18 Bolt insertion hole 20 Cylindrical portion 22 Flange portion 24 Outer divided body 26 Divided end portion 28 Divided portion 30 Hole groove 32 Hole hole 34 Rubber arm 36 Inner cylindrical portion 38 Outer cylindrical portion 40 Stopper rubber 42 Connecting rubber 44 Void 46 Inner concave surface 48 Outer concave surface 50 Connection surface 52 Mounting hole 54 Holder 60 Cylindrical vibration-proof device (second embodiment)
62 outer cylindrical member

Claims (4)

A cylindrical vibration-damping device in which an inner shaft member and an outer cylindrical member made of synthetic resin are connected by a main rubber elastic body,
the main rubber elastic body includes a pair of rubber arms extending from the inner shaft member to both sides and radially connecting the inner shaft member and the outer tubular member,
the outer tubular member has a circumferentially divided portion on an outer circumferential side of the rubber arm,
A connecting rubber is disposed in the divided portion, the connecting rubber connecting both sides of the divided portion of the outer tubular member in a circumferential direction,
The cylindrical vibration-isolating device has an outer circumferential end of the rubber arm, and a void is formed on the inner periphery of the connecting rubber, penetrating the arm in the axial direction. The cylindrical vibration-isolating device according to claim 1, in which the inner peripheral surface of the connecting rubber that constitutes the inner wall surface of the cavity extends in the axial direction with a concave cross section that opens toward the inner circumference. A cylindrical vibration-damping device according to claim 1 or 2, in which the maximum circumferential width of the cavity is greater than the circumferential width of the divided portion of the outer cylindrical member. The outer cylinder member is a divided structure constituted by a pair of outer divided bodies,
A pair of divided portions are formed between circumferential ends of the pair of outer divided bodies,
The cylindrical vibration isolator according to claim 1 or 2, wherein the pair of divided portions are provided on each outer peripheral side of the pair of rubber arms.

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