Cylindrical vibration isolation device

Abstract

To provide a cylindrical vibration isolation device of a new structure that can achieve a small diameter in the axial middle portion of an inner shaft member and easy manufacturing, while ensuring an outer diameter dimension capable of fulfilling various functions at both ends of the inner shaft member.SOLUTION: A cylindrical vibration isolation device 10 has an inner shaft member 12 and an outer cylindrical member 14, which are connected by a main rubber elastic body 16. An inner body 18 constituting the inner shaft member 12 is cylindrical and extends in the axial direction with a constant cross-sectional shape. A first plate member 32 and a second plate member 34, which have a larger diameter than the inner body 18, are stacked on both axial end faces of the inner body 18, and the first plate member 32 and the second plate member 34 are fixed to the inner peripheral surface of the inner body 18. The first plate member 32 and second plate member 34 attached to the inner body 18 have mutually different shapes.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cylindrical vibration isolator used for an engine mount or the like of an automobile.

Background Art

[0002] Conventionally, a cylindrical vibration isolator has been adopted as an engine mount, a subframe mount, a suspension bush, or the like of an automobile. As disclosed in Japanese Patent Application Laid-Open No. 2010-203526 (Patent Document 1) and the like, the cylindrical vibration isolator has a structure in which an inner shaft member and an outer cylinder member are connected by a main body rubber elastic body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, if a bolt seating surface or a tapered shape for guiding is provided at both ends in the axial direction of the inner shaft member, it is difficult to reduce the diameter of the inner shaft member, the design freedom regarding vibration isolation characteristics and durability is restricted, or it may be difficult to meet the need for weight reduction.

[0006] The problem to be solved by the present invention is to provide a cylindrical vibration damping device with a novel structure that can achieve a smaller diameter and easier manufacturing in the axial intermediate portion of the inner shaft member, while ensuring an outer diameter dimension that enables various functions at both ends of the inner shaft member. [Means for solving the problem]

[0007] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is illustrative and can be combined with others as appropriate. Furthermore, the multiple components described in each embodiment can be recognized and adopted as independently as possible, and can be combined with any component described in another embodiment as appropriate. Thus, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0008] The first embodiment is a cylindrical vibration damping device in which an inner shaft member and an outer cylindrical member are connected by a main body rubber elastic body, wherein the inner body constituting the inner shaft member is cylindrical with a certain cross-sectional shape and extends in the axial direction, and a first plate member and a second plate member, which have a larger diameter than the inner body, are superimposed on both axial end faces of the inner body, and the first plate member and the second plate member are fixed to the inner circumferential surface of the inner body, and the first plate member and the second plate member attached to the inner body have different shapes from each other.

[0009] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, the inner body constituting the intermediate portion of the inner shaft member is a small-diameter cylindrical body with a simple structure having a constant cross-sectional shape in the axial direction, while the first and second plate members attached to both axial ends of the inner body allow the axial ends of the inner shaft member to have a larger diameter than the inner body. Furthermore, since the first and second plate members are provided on both sides of the inner body in the axial direction with mutually different shapes, mutually different functions can be set for both axial ends of the inner shaft member by these first and second plate members. Note that the first and second plate members being mutually different shapes includes, for example, cases where they are similar in shape or have different sizes.

[0010] The second embodiment is a cylindrical vibration damping device as described in the first embodiment, wherein the inner body is a metal member formed by forging or drawing, and the first plate member and the second plate member are pressed metal fittings.

[0011] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, the inner body can be made small in diameter, making it easy to form the inner body by forging or drawing. Furthermore, first and second plate members of various shapes can be easily obtained using press fittings.

[0012] The third embodiment is a cylindrical vibration isolation device described in the second embodiment, wherein the same pressed metal fitting is used for both the first plate member and the second plate member.

[0013] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, the number of types of parts to be manufactured can be reduced by using the same press fittings to constitute the first and second plate members. Furthermore, when the same press fittings are used for the first and second plate members, the first and second plate members can be made to have different shapes by processing at least one of the press fittings before or after attachment to the inner body.

[0014] The fourth aspect is a cylindrical vibration isolation device as described in the third aspect, wherein the first plate member and the second plate member have different shapes in the portions that protrude outward from the inner body, while they have the same shape in the inner portions that are superimposed on the inner body.

[0015] In the cylindrical vibration isolation device according to this embodiment, the first and second plate members have different outer circumferential portions with different shapes, thereby realizing different functions, while the inner circumferential portions, which are the mounting parts to the inner body, have the same shape, thus enabling the common mounting structure to the inner body.

[0016] The fifth embodiment is a cylindrical vibration damping device described in any one of the first to fourth embodiments, wherein the inner body has a groove formed on its inner circumferential surface that opens and extends linearly in the axial direction, and the first plate member and the second plate member are provided with fixing pieces that are inserted into the groove of the inner body, and the tip portion of the fixing piece is a fitting portion that is wider than the base portion, and the fitting portion is fitted into the groove and fixed.

[0017] In the cylindrical vibration isolation device constructed according to this embodiment, the fixing pieces of the first and second plate members are partially fixed to the inner body in the circumferential direction, making the fixing work easier compared to when they are press-fitted around the entire circumference. Furthermore, since the fitting portion at the tip of the fixing piece is fitted into the groove of the inner body for fixing, the fixing piece can be easily bent and deformed at its base end. For example, when the flat first and second plate members are stacked on the inner body, the fixing work becomes easier by bending and deforming the base end of the fixing piece to fit the fitting portion into the groove of the inner body.

[0018] The sixth aspect is the cylindrical vibration isolator according to any one of the first to fifth aspects, wherein the first plate member is a seating surface securing member that forms a seating surface for a bolt inserted through the inner shaft member, and the second plate member is provided with a guide surface that tapers outward in the axial direction on its outer peripheral surface, and serves as a guide member for guiding the mounting position of the inner shaft member with respect to the member to which the inner shaft member is to be mounted.

[0019] According to the cylindrical vibration isolator having the structure according to this aspect, while reducing the outer diameter of the inner body, the area of the axial end surface of the inner shaft member required for the bolt seating surface can be secured by the first plate member, and a tapered guide surface can be set on the outer peripheral surface of the axial end portion of the inner shaft member by the second plate member.

Advantages of the Invention

[0020] According to the present invention, while securing an outer diameter dimension capable of realizing various functions at both ends of the inner shaft member, it is possible to reduce the diameter and facilitate manufacturing in the axial intermediate portion of the inner shaft member.

Brief Description of the Drawings

[0021] [Figure 1] Front view showing a cylindrical vibration isolator as a first embodiment of the present invention [Figure 2] Rear view of the cylindrical vibration isolator shown in FIG. 1 [Figure 3] Cross-sectional view taken along line III-III of FIG. 1 [Figure 4] Cross-sectional view taken along line IV-IV of FIG. 1 [Figure 5] Cross-sectional view taken along line V-V of FIG. 3 [Figure 6] [[ID=Z34]]Front view showing an integrally vulcanized molded product of the main body rubber elastic body constituting the cylindrical vibration isolator of FIG. 1 [Figure 7] Cross-sectional view taken along line VII-VII of FIG. 6 [Figure 8] Cross-sectional view taken along line VIII-VIII of FIG. 7 [Figure 9] Front view showing an enlarged view of the press fitting constituting the cylindrical vibration isolator of FIG. 1 [Figure 10]Front view showing a cylindrical vibration isolation device as a second embodiment of the present invention. [Figure 11] Figure 10: Cross-sectional view between XI and XI [Figure 12] Figure 10 is a front view showing an enlarged view of the press fittings that constitute the cylindrical vibration damping device. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings.

[0023] Figures 1 to 5 show a cylindrical vibration isolation device 10 as a first embodiment of the present invention. The cylindrical vibration isolation device 10 has a structure in which an inner shaft member 12 and an outer cylindrical member 14 are connected by a main rubber elastic body 16. In the following description, as a general rule, the vertical direction refers to the vertical direction in Figure 1, the left-right direction refers to the left-right direction in Figure 1, and the front-back direction refers to the vertical direction in Figure 3.

[0024] The inner shaft member 12 comprises a cylindrical inner body 18. As shown in Figures 6 to 8, the inner body 18 is formed of, for example, metal, and extends continuously in the axial direction with a substantially constant cross-sectional shape, preferably formed by forging or drawing. The inner body 18 has a substantially cylindrical outer surface. The inner body 18 is provided with a central hole 20 that penetrates in the axial direction, and in this embodiment, the central hole 20 has a substantially elliptical cross-section with the left-right direction as the major axis. A pair of recessed grooves 22, 22 are formed in the inner body 18. The recessed grooves 22 open to the inner surface of the inner body 18 and extend linearly in the axial direction. In this embodiment, one recessed groove 22 is provided on each side in the direction of the minor axis of the central hole 20.

[0025] An outer cylindrical member 14 is fitted onto the inner body 18. The outer cylindrical member 14 is made of, for example, metal or synthetic resin, and its inner diameter is larger than the outer diameter of the inner body 18, and it is shorter in the axial direction than the inner body 18. A flange portion 23 that protrudes outward is formed at one end of the outer cylindrical member 14 in the axial direction. The outer cylindrical member 14 only needs to be cylindrical as a whole, and may be, for example, a C-shaped annular body divided in a part in the circumferential direction, or a divided structure divided at multiple points in the circumferential direction.

[0026] An outer cylindrical member 14 is positioned externally to the inner body 18, and a main rubber elastic body 16 is formed radially between the inner body 18 and the outer cylindrical member 14. The main rubber elastic body 16 is substantially cylindrical in shape overall. The inner circumferential surface of the main rubber elastic body 16 is vulcanized and bonded to the outer circumferential surface of the inner body 18, and the outer circumferential surface is vulcanized and bonded to the inner circumferential surface of the outer cylindrical member 14, forming an integrally vulcanized molded product comprising the inner body 18 and the outer cylindrical member 14. A groove 24 extending in an annular shape in the circumferential direction is formed on the axial end face of the main rubber elastic body 16. A pair of grooves 26, 26 penetrating in the axial direction are formed on both the upper and lower sides of the main rubber elastic body 16 relative to the inner body 18. The grooves 26 extend substantially in the left-right direction, with both left and right ends reaching beyond the inner body 18 in the left-right direction. Between the top and bottom of the pair of cut holes 26, 26 in the main rubber elastic body 16, a pair of rubber arms 28, 28 are formed that extend in the left-right direction and connect the inner body 18 and the outer cylindrical member 14 in the left-right direction. Above and below the pair of cut holes 26, 26 in the main rubber elastic body 16, a pair of stopper rubbers 30, 30 are formed that protrude inward from the outer cylindrical member 14 toward the inner body 18, and the relative vertical displacement between the inner body 18 and the outer cylindrical member 14 is limited by the contact between the stopper rubbers 30 and the inner body 18.

[0027] The inner body 18, which constitutes the integrally vulcanized molded product of the main rubber elastic body 16, has a first plate member 32 and a second plate member 34 attached to it. The first plate member 32 and the second plate member 34 are made up of a common press fitting 36 as shown in Figure 9.

[0028] The press fitting 36 is generally disc-shaped, and its outer diameter is larger than that of the inner body 18. The press fitting 36 has a through hole 38 that penetrates through the central part in the thickness direction. The through hole 38 in this embodiment has a generally circular cross-section, and its diameter is approximately the same as the minor axis radius of the central hole 20 of the inner body 18. Partially enlarged diameter portions 40, 40 are provided on both the upper and lower sides of the through hole 38. The press fitting 36 is provided with fixing pieces 42 that protrude inward from each enlarged diameter portion 40. The fixing pieces 42 protrude linearly from the left and right center of the enlarged diameter portion 40 in the vertical direction toward the inner circumference of the through hole 38. The base end portion of the fixing piece 42 is a deformation-allowing portion 44 that extends linearly in the vertical direction with a generally constant left-right width. The tip portion of the fixing piece 42 is a fitting portion 46 that is wider than the deformation-allowing portion 44. The fitting portion 46 is shorter in the vertical direction than the deformation-allowable portion 44. It is desirable that the left-right width dimension of the fitting portion 46 be at least 1.2 times and no more than 2 times the left-right width dimension of the deformation-allowable portion 44.

[0029] The press fitting 36 is superimposed on the axial end face of the inner body 18, and is bent and deformed in the deformation-allowable portion 44 so that the fixing pieces 42, 42 fit into the central hole 20 of the inner body 18. Then, each fixing piece 42 is inserted into each groove 22 that opens on the inner circumferential surface of the inner body 18, and the fitting portion 46 of the fixing piece 42 is fitted into the left and right inner surfaces of the groove 22, thereby fixing and attaching the press fitting 36 to the inner circumferential surface of the inner body 18.

[0030] The press fitting 36 attached to one axial end face (front end face) of the inner body 18 is designated as the first plate member 32 upon attachment to the inner body 18. On the other hand, the press fitting 36 attached to the other axial end face (rear end face) of the inner body 18, as shown in Figures 3 and 4, is designated as the second plate member 34 after attachment to the inner body 18. The outer peripheral end that protrudes further outward than the inner body 18 is designated as a tapered guide portion 48 with a smaller diameter toward the other axial direction (rear).

[0031] Thus, the first plate member 32 and the second plate member 34 of this embodiment are made of the same press fitting 36, and when attached to the inner body 18, a guide portion 48 is formed on the second plate member 34, resulting in mutually different shapes. The first plate member 32 and the second plate member 34 of this embodiment have mutually different shapes in the outer peripheral portions that protrude from the inner body 18 to the outer circumference, while having mutually the same shape in the inner peripheral portions attached to the inner body 18.

[0032] The inner shaft member 12 is formed by attaching the first plate member 32 and the second plate member 34 to the inner body 18. Therefore, the cylindrical vibration isolation device 10 has a structure in which the inner shaft member 12 and the outer cylindrical member 14 are connected by the main body rubber elastic body 16.

[0033] In this embodiment, the inner body 18 extends straight with a fixed cross-sectional shape. Furthermore, since the first and second plate members 32 and 34 are formed by fixing the press fittings 36, 36 to the inner body 18 which constitutes an integrally vulcanized molded product of the main rubber elastic body 16, when the main rubber elastic body 16 is vulcanized, the inner body 18 without the first and second plate members 32 and 34 is set in the mold for vulcanizing the main rubber elastic body 16. As a result, when setting the inner body 18 in the mold for vulcanizing the main rubber elastic body 16, only the circumferential orientation of the inner body 18 needs to be set to an appropriate orientation, and the axial orientation is not restricted. Therefore, it is possible to prevent the inner body 18 from being positioned in an incorrect axial orientation relative to the main rubber elastic body 16. In particular, by making the inner body 18 a simple structure extending in a single cross-section, it is not necessary to specify the axial orientation of the inner body 18. As a result, errors in the axial orientation of the inner body 18 can be prevented inexpensively and with a simple structure without forming a special positioning structure on the inner body 18 relative to the main rubber elastic body 16.

[0034] The inner shaft member 12 is fixed to the vehicle body 52, which is the mounting target member, by bolts 50 inserted through the central hole 20 of the inner body 18 and the through holes 38, 38 of the first and second plate members 32, 34. In this embodiment, since the through holes 38, 38 of the first and second plate members 34 have a circular cross-section, the bolts 50 are inserted through the through holes 38, 38 to position the inner shaft member 12 in the left-right direction.

[0035] The bolt 50 inserted through the inner shaft member 12 has its head 54 superimposed on one axial end face of the inner shaft member 12. Since one axial end of the inner shaft member 12 is formed by the first plate member 32, the axial outer surface of the first plate member 32 forms the seating surface for the head 54 of the bolt 50. Because the first plate member 32 of the inner shaft member 12 has a larger diameter than the inner body 18 and protrudes further outward than the inner body 18, a large area is secured on one axial end face without increasing the diameter of the inner body 18, and the seating surface for the head 54 of the bolt 50 can be formed with a sufficiently large area.

[0036] The other axial end of the inner shaft member 12, which is composed of the second plate member 34, is inserted into a guide recess 56 provided in the vehicle body 52. ​​Since the outer peripheral end of the second plate member 34 is provided with a guide portion 48 having a tapered guide surface as its outer peripheral surface, the inner shaft member 12 is positioned relative to the vehicle body 52 by being inserted into the guide recess 56.

[0037] Thus, the inner shaft member 12 is composed of a first plate member 32 and a second plate member 34, whose axial ends have mutually different shapes, and thus each of its axial ends has a mutually different function. Specifically, in this embodiment, one axial end of the inner shaft member 12, which is composed of the first plate member 32, is provided with a seating surface for the head 54 of the bolt 50, and the first plate member 32 is used as the seating surface member that forms the seating surface. The other axial end of the inner shaft member 12, which is composed of the second plate member 34, is provided with a positioning function relative to the vehicle body 52, and the second plate member 34 is used as a guide member.

[0038] Since the functions of both axial ends of the inner shaft member 12 are realized by the first and second plate members 32 and 34, the inner body 18 located between the axial ends of the first and second plate members 32 and 34 can have a simple structure that extends axially with a constant cross-section, and it is also easy to reduce its diameter. Therefore, it becomes easier to improve durability by ensuring the free length of the main body rubber elastic material 16 and to ensure the degree of freedom in tuning the spring characteristics, and it also becomes possible to obtain the inner body 18 inexpensively by forging or drawing.

[0039] The first and second plate members 32 and 34 are constructed using a common press fitting 36, which reduces manufacturing costs, improves production efficiency, and simplifies parts management through the commonality of parts. In particular, the press fitting 36 can be easily and inexpensively manufactured by press working. Furthermore, if the common press fittings 36, 36 are attached to both axial ends of the inner body 18 and then processed into a shape that can realize the functions of the first and second plate members 32 and 34, it is possible to prevent the first and second plate members 32 and 34 from being installed at the wrong axial ends of the inner body 18.

[0040] The outer cylindrical member 14 is attached to the holder 58 by press-fitting it into a mounting hole 60 formed in the holder 58. The holder 58 is a cylindrical portion provided on a vehicle body 52 that is to be vibration-damped, such as a subframe or a power unit, and is equipped with a mounting hole 60. Therefore, when the inner shaft member 12 is attached to the vehicle body 52 and the outer cylindrical member 14 is attached to the holder 58, the holder 58, such as a subframe or a power unit, is vibration-damped and connected to the vehicle body 52 via the cylindrical vibration damping device 10.

[0041] Figures 10 and 11 show a cylindrical vibration isolation device 70 as a second embodiment of the present invention. The cylindrical vibration isolation device 70 has a structure in which an inner shaft member 72 and an outer cylindrical member 14 are elastically connected by a main rubber elastic body 16. In the description of the second embodiment, parts that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the figures and their description is omitted.

[0042] The inner shaft member 72 has a structure in which a first plate member 74 and a second plate member 76 are attached to both axial ends of the inner body 18, which is common to the first embodiment. The first plate member 74 and the second plate member 76 are made of a common press fitting 78, and the second plate member 76 has a guide portion 48 on its outer circumference, similar to the second plate member 34 of the first embodiment.

[0043] As shown in Figure 12, the press fitting 78 is generally disc-shaped, with a through hole 80 extending through it in the thickness direction in its central portion. The through hole 80 has a roughly oval cross-section corresponding to the central hole 20 of the inner body 18, with the left-right direction (left-right direction in Figure 12) being its long axis. The press fitting 78 also has a pair of fixing pieces 42, 42 that protrude into the through hole 80 in the vertical direction, and, similar to the press fitting 36 of the first embodiment, is fixed to the inner circumferential surface of the inner body 18 by the fixing pieces 42, 42, thereby forming the first and second plate members 74, 76.

[0044] By constructing the first and second plate members 74 and 76 with press fittings 78 having through holes 80 with an oval cross-section, it becomes possible to adjust the insertion position of the bolts 50 into the inner shaft member 72 in the left-right direction, making it easier to tolerate dimensional errors when bolting the inner shaft member 72 to the vehicle body.

[0045] In this case, since the same inner body 18 as in the first embodiment is used, by selectively attaching the press fitting 36 and the press fitting 78 to the single-structure inner body 18, it becomes possible to selectively obtain inner shaft members 12 or inner shaft members 72 with different cross-sectional shapes of the bolt insertion holes. In particular, in a vulcanized molded product of a main rubber elastic body 16 equipped with an inner body 18, by attaching the press fitting 36 (78) to the inner body 18, it becomes possible to selectively form the above-mentioned multiple types of inner shaft members 12 (72) while using a common structure for the integrally vulcanized molded product of the main rubber elastic body 16 equipped with an inner body 18 and an outer cylindrical member 14. Therefore, when manufacturing the above-mentioned multiple types of inner shaft members 12(72), it becomes unnecessary to prepare molds and manufacturing equipment to obtain multiple types of inner bodies with different structures (such as those with an oval cross-section and those with a circular cross-section for the central hole 20), and it also becomes unnecessary to prepare multiple types of molds for vulcanizing the main rubber elastic body 16, thereby enabling a significant reduction in manufacturing costs and simplification of the manufacturing process.

[0046] Although embodiments of the present invention have been described in detail above, the present invention is not limited by its specific description. For example, the mounting structure of the first plate member and the second plate member to the inner body is not limited to the specific structure of the above embodiment. For example, cylindrical portions projecting in the axial direction may be provided at the inner circumferential ends of the first and second plate members, and the first and second plate members may be fixed to the inner circumferential surface of the inner body by press-fitting the cylindrical portions into the central hole of the inner body.

[0047] The first plate member and the second plate member may have different shapes before being attached to the inner body. Furthermore, the first plate member and the second plate member can be considered to have different shapes even if they are similar in shape but different in size.

[0048] The first and second plate members are not limited to a seating surface member for securing the bolt seating surface and a guide member for positioning the inner shaft member relative to the mounting target member. Specifically, for example, the first plate member can be extended to a position facing the flange portion 23 of the outer cylindrical member 14 in the axial direction, thereby forming a stopper that limits the relative axial displacement between the inner shaft member 12 and the outer cylindrical member 14 by contact between the first plate member and the flange portion 23 of the outer cylindrical member 14.

[0049] For example, the press fitting 36 shown in Figure 9 can be used as the first plate member, and the press fitting 78 shown in Figure 12 can be used as the second plate member. In this case, for example, since the first plate member and the second plate member are made up of press fittings 36 and 78 with different shapes, it is possible to obtain a first plate member and a second plate member with different shapes without performing bending or other processing on the outer circumference of the press fitting 36 after attachment to the inner body 18, as shown in the first embodiment. In short, the parts of the first plate member and the second plate member that have different shapes are not necessarily limited to the outer circumference that protrudes from the inner body 18, but may also be the inner circumference. [Explanation of symbols]

[0050] 10. Cylindrical Vibration Isolator (First Embodiment) 12 Inner shaft member 14 Outer cylindrical member 16 Main body rubber elastic body 18 Inner body 20 center hole 22 grooves 23 Flange section 24 Straight groove 26 slit holes 28 Rubber Arms 30 Stopper rubber 32 First plate member 34 Second plate member 36 Press fittings 38 Through holes 40 Expanded diameter part 42 Fixed piece 44 Deformation allowable area 46 Fitting part 48 Guide section 50 volts 52 Vehicle body (parts to be attached) 54 Head 56 Guide recess 58 Holder 60 mounting holes 70. Cylindrical Vibration Isolator (Second Embodiment) 72 Inner shaft member 74 First plate member 76 Second plate member 78 Press fittings 80 Through holes

Claims

1. A cylindrical vibration isolation device in which an inner shaft member and an outer cylindrical member are connected by a main body rubber elastic material, The inner body constituting the inner shaft member is cylindrical with a fixed cross-sectional shape and extends in the axial direction. A first plate member and a second plate member, each having a larger diameter than the inner body, are superimposed on both axial ends of the inner body, and these first and second plate members are fixed to the inner circumferential surface of the inner body. A cylindrical vibration isolation device in which the first plate member and the second plate member attached to the inner body have different shapes from each other.

2. The inner body is a metal member formed by forging or drawing. The cylindrical vibration isolation device according to claim 1, wherein the first plate member and the second plate member are press fittings.

3. The cylindrical vibration damping device according to claim 2, wherein the same pressed metal fitting is used as the first plate member and the second plate member.

4. The cylindrical vibration damping device according to claim 3, wherein the first plate member and the second plate member have different shapes in the portions that protrude outward from the inner body, while they have the same shape in the inner portions attached to the inner body.

5. The inner body has a groove formed on its inner circumferential surface that opens and extends linearly in the axial direction. The first plate member and the second plate member are each equipped with a fixing piece that is inserted into the groove of the inner body. The cylindrical vibration damping device according to claim 1 or 2, wherein the fixing piece has a fitting portion at its tip that is wider than the base portion, and the fitting portion is fitted into the groove and fixed.

6. The first plate member is a seating surface member that forms a seating surface for a bolt inserted into the inner shaft member. The cylindrical vibration damping device according to claim 1 or 2, wherein the second plate member is provided with a guide surface on its outer circumference that becomes smaller in diameter in the axial direction outward, and serves as a guide member for guiding the mounting position of the inner shaft member with respect to the mounting target member.

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