Dynamic damper

Abstract

The dynamic damper (1) comprises a rubber elastic body (30) press-fitted into a mounting hole (13) of a bracket (10), and a mass member (20) supported by the rubber elastic body (30). The rubber elastic body (30) is provided with a leg portion (33) interposed between an inner cylinder portion (31) and an outer cylinder portion (32). An inner bent portion (33b) is formed at one end of the extended portion (33a) of the leg portion (33), which is connected to the outer circumferential surface of the inner cylinder portion (31), and an outer bent portion (33c) is formed at the other end of the extended portion (33a), which is connected to the inner circumferential surface of the outer cylinder portion (32). In this configuration, the rubber elastic body (30) can be press-fitted and held in the bracket (10).

Description

Technical Field

[0001] The present invention relates to a dynamic damper.

Background Art

[0002] In a dynamic damper that absorbs vibrations of a vibrating member such as an automobile body, a rubber elastic body is interposed between a bracket and a mass member. The bracket is attached to the vibrating member. When vibrations occur in the vibrating member, the mass member moves relative to the bracket, and the rubber elastic body elastically deforms between the bracket and the mass member to absorb the vibrations of the vibrating member. As the rubber elastic body of the dynamic damper, there is one in which an inner cylinder portion fitted to the mass member, an outer cylinder portion fitted to the mounting hole of the bracket, and a leg portion interposed between the inner cylinder portion and the outer cylinder portion are formed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described dynamic damper, from the viewpoint of manufacturing cost and the like, it is desirable to press-fit and hold the rubber elastic body between the bracket and the mass member. In this case, when the mass member moves relative to the bracket, it is necessary to hold the rubber elastic body on the bracket so that the rubber elastic body does not come off the bracket.

[0005] An object of the present invention is to provide a dynamic damper that solves the above-described problems and can press-fit and hold a rubber elastic body on a bracket.

Means for Solving the Problems

[0006] To solve the aforementioned problems, the present invention provides a dynamic damper comprising a bracket having a mounting hole, a rubber elastic body press-fitted into the mounting hole, and a mass member supported by the rubber elastic body. The rubber elastic body comprises an inner cylinder portion fitted to the outer circumferential surface of the mass member, an outer cylinder portion fitted to the inner circumferential surface of the mounting hole, and a leg portion interposed between the outer circumferential surface of the inner cylinder portion and the inner circumferential surface of the outer cylinder portion. The leg portion has an extended portion that extends in the axial direction of the rubber elastic body. An inner bent portion is formed at one end of the extended portion in the axial direction, connected to the outer circumferential surface of the inner cylinder portion, and an outer bent portion is formed at the other end of the extended portion in the axial direction, connected to the inner circumferential surface of the outer cylinder portion.

[0007] In the dynamic damper of the present invention, vibrations generated in the vibrating member cause the mass member to move to the other side relative to the bracket. As the mass member moves, the inner cylinder portion of the rubber elastic body moves to the other side relative to the outer cylinder portion, causing the inner bent portion of the leg portion to approach the outer bent portion and the extended portion to be pushed in. As a result, the leg portion deforms so that its cross-section along the axial direction becomes approximately S-shaped. Furthermore, as the mass member moves to the other side relative to the bracket and the inner bent portion moves beyond the outer bent portion to the other side, the extended portion flips over, and the leg portion deforms into a approximately straight shape. Thus, in the dynamic damper of the present invention, the crank-shaped legs interposed between the inner and outer cylinder portions of the rubber elastic body are pushed in the axial direction and deform, which reduces the pull-out load that acts to separate the bracket from the rubber elastic body, allowing the rubber elastic body to be press-fitted and held in place by the bracket.

[0008] In the dynamic damper described above, it is preferable to provide a press-fit holding region. The press-fit holding region is a region in which the pressure contact region between the mass member and the inner cylinder and the pressure contact region between the mounting hole and the outer cylinder overlap with a gap in the radial direction of the rubber elastic body, and it is preferable to align the press-fit holding region and the leg portion in the axial direction.

[0009] In this configuration, a space is formed in the area where the rubber elastic body is pressed against the mounting hole. This allows for reduced variation in the spring characteristics of the rubber elastic body, even when the dimensions of the mounting holes vary within tolerance from product to product, resulting in inconsistent press-fitting of the rubber elastic body into the mounting hole. Therefore, the quality of the dynamic damper can be stabilized.

[0010] In this invention, the state in which the press-fit holding region and the leg portion are aligned in the axial direction includes not only the state in which the press-fit holding region and the leg portion are aligned without overlapping, but also the state in which a part of the leg portion enters the press-fit holding region and the press-fit holding region and the leg portion are aligned.

[0011] It is preferable to form an engaging portion on the outer cylinder portion that engages with the edge of the mounting hole, and to provide the press-fit holding area between the engaging portion and the leg portion. In this way, when the mass member moves to the other side relative to the bracket, deformation of the engagement portion is suppressed, and the engagement state between the mounting hole and the engagement portion can be maintained. [Effects of the Invention]

[0012] In the dynamic damper of the present invention, the pull-out load that acts to separate the bracket and the rubber elastic body is small, preventing the rubber elastic body from coming out of the bracket. As a result, the rubber elastic body can be assembled by press-fitting it into the bracket, simplifying the assembly work of the dynamic damper and, consequently, reducing the manufacturing cost of the dynamic damper. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a dynamic damper according to an embodiment of the present invention. [Figure 2] This is a side cross-sectional view showing a dynamic damper according to an embodiment of the present invention. [Figure 3] This is a side cross-sectional view showing the side portion of a dynamic damper according to an embodiment of the present invention. [Figure 4]This is a side cross-sectional view showing the leg portion of a dynamic damper according to an embodiment of the present invention in a compressed state. [Figure 5] This is a side cross-sectional view showing a state in which the leg portion of a dynamic damper according to an embodiment of the present invention is deformed into a substantially straight shape. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. The dynamic damper 1 of this embodiment, shown in Figure 1, is attached to the back door of an automobile and absorbs vibrations that occur in the back door when the automobile is in motion. The dynamic damper 1 comprises a bracket 10, two rubber elastic bodies 30, 30 attached to the bracket 10, and a mass member 20 supported by both rubber elastic bodies 30, 30.

[0015] Bracket 10 is a metal component that is attached to the back door. Bracket 10 has a mounting plate 11 with a plurality of connecting holes 11a formed therein, and two side plates 12, 12 formed at both ends of the mounting plate 11. The side plates 12, 12 are arranged parallel to each other with a gap in the axial direction L. As shown in Figure 3, a circular mounting hole 13 is provided in the side plate 12. The edge 13a of the mounting hole 13 is raised outward in the axial direction L relative to the outer surface of the side plate 12.

[0016] As shown in Figure 2, the mass member 20 is a metal weight. The mass member 20 comprises a cylindrical main body portion 21 extending in the axial direction L, and shaft portions 22, 22 protruding from both end faces 21a, 21a of the main body portion 21. The shaft portion 22 protrudes axially in the direction L from the center of the end face 21a of the main body portion 21. The shaft portion 22 is inserted into the center of the mounting hole 13 of the bracket 10.

[0017] The shaft portion 22 is a cylindrical member. As shown in FIG. 3, a rib 22a protruding in the radial direction is formed at the tip of the shaft portion 22. The shaft portion 22 is attached to the end face 21a of the main body portion 21. When attaching the shaft portion 22 to the main body portion 21, first, the threaded portion of the bolt B inserted into the shaft portion 22 from the outside is screwed into the threaded hole formed in the end face of the main body portion 21. Then, by bringing the head of the bolt B into contact with the rib 22a of the shaft portion 22, the shaft portion 22 is attached to the end face 21a of the main body portion 21. Note that the shaft portion 22 may be integrally formed with the main body portion 21.

[0018] The rubber elastic body 30 is a rubber elastic member press-fitted into the mounting hole 13. The rubber elastic body 30 is interposed between the inner peripheral surface of the mounting hole 13 of the bracket 10 and the outer peripheral surface of the shaft portion 22 of the mass member 20. As shown in FIG. 2, in this embodiment, two rubber elastic bodies 30, 30 are attached to the bracket 10. Since both rubber elastic bodies 30, 30 are symmetrically configured in the axial direction L, in this embodiment, one rubber elastic body 30 will be described, and the description of the other rubber elastic body 30 will be omitted.

[0019] As shown in FIG. 3, the rubber elastic body 30 includes an inner cylinder portion 31 fitted onto the outer peripheral surface of the shaft portion 22 of the mass member 20, an outer cylinder portion 32 fitted onto the inner peripheral surface of the mounting hole 13, and a leg portion 33 interposed between the outer peripheral surface of the inner cylinder portion 31 and the inner peripheral surface of the outer cylinder portion 32.

[0020] The inner cylinder portion 31 is formed in a cylindrical shape. The shaft portion 22 is press-fitted into the inner cylinder portion 31, and the inner peripheral surface of the inner cylinder portion 31 and the outer peripheral surface of the shaft portion 22 are in pressure contact. One end of the inner cylinder portion 31 abuts against the rib 22a of the shaft portion 22, and the other end of the inner cylinder portion 31 abuts against the end face 21a of the main body portion 21.

[0021] The outer cylinder portion 32 is formed in a cylindrical shape. The outer cylinder portion 32 is formed with an engaging portion 32a that engages with the edge portion 13a of the mounting hole 13, a fitting portion 32b that is fitted into the mounting hole 13, and a stopper portion 32c disposed on the inner surface side of the side plate 12.

[0022] The fitting portion 32b is press-fitted into the mounting hole 13, and the outer surface of the fitting portion 32b and the inner surface of the mounting hole 13 are in pressure contact. In the dynamic damper 1 of this embodiment, a press-fit holding region S is provided. The press-fit holding region S is a region in which the press-fit contact region between the mass member 20 and the inner cylinder portion 31 and the press-fit contact region between the mounting hole 13 and the outer cylinder portion 32 overlap with a gap in the radial direction of the rubber elastic body 30. In the press-fit holding region S, the inner circumferential surface of the inner cylinder portion 31 is pressed against the outer circumferential surface of the shaft portion 22, and the outer circumferential surface of the outer cylinder portion 32 is pressed against the inner circumferential surface of the edge portion 13a of the mounting hole 13.

[0023] The engaging portion 32a is located on the outer surface side of the side plate 12. The engaging portion 32a is the outer end of the outer cylinder portion 32, which is enlarged in diameter compared to the mounting hole 13. The engaging portion 32a engages with the edge portion 13a of the mounting hole 13 inward in the axial direction L.

[0024] The stopper portion 32c is located on the inner surface side of the side plate 12. The stopper portion 32c is the inner end of the outer cylinder portion 32, which is enlarged in diameter beyond the mounting hole 13. The stopper portion 32c engages with the inner surface of the side plate 12 in the outward direction in the axial direction L. That is, the stopper portion 32c is located between the end face 21a of the main body portion 21 of the mass member 20 and the side plate 12, and contacts the side plate 12 from the mass member 20 side. A gap is formed between the stopper portion 32c and the end face 21a of the main body portion 21.

[0025] The leg portion 33 is a so-called rubber foot, and is interposed between the outer circumferential surface of the inner cylinder portion 31 and the inner circumferential surface of the stopper portion 32c of the outer cylinder portion 32. The leg portion 33 has a cylindrical extension portion 33a formed around the axis of the central axis of the rubber elastic body 30. The extension portion 33a extends in the axial direction L.

[0026] An inner bent portion 33b is formed at the outer end in the axial direction L of the extended portion 33a. In this embodiment, the "outer end in the axial direction L" corresponds to the "one end in the axial direction" in the claims. The inner bent portion 33b is a part in which the outer end of the extended portion 33a is curved radially inward of the rubber elastic body 30, and is connected to the outer circumferential surface of the inner cylindrical portion 31.

[0027] An outer bent portion 33c is formed at the inner end in the axial direction L of the extended portion 33a. In this embodiment, the "inner end in the axial direction L" corresponds to the "other end in the axial direction" in the claims. The outer bent portion 33c is a portion in which the inner end of the extended portion 33a is curved radially outward from the rubber elastic body 30, and is connected to the inner circumferential surface of the stopper portion 32c of the outer cylinder portion 32. In this embodiment, the outer bent portion 33c is positioned between the end face 21a of the main body portion 21 of the mass member 20 and the inner bent portion 33b.

[0028] The cross-section of the leg portion 33 along the axial direction L is formed in a crank shape with both ends in the axial direction L bent. In the dynamic damper 1 of this embodiment, the press-fit holding region S and the leg portion 33 are arranged in the axial direction, and the press-fit holding region S is provided between the engaging portion 32a and the leg portion 33.

[0029] In the dynamic damper 1 of this embodiment, as shown in Figure 4, vibrations generated in the back door may cause the mass member 20 to move inward relative to the side plate 12 of the bracket 10. That is, there is a timing when one side plate 12 of the bracket 10 approaches the main body 21 of the mass member 20, and the other side plate 12 moves away from the main body 21. When the side plate 12 separates from the main body 21, the inner cylinder portion 31 of the rubber elastic body 30 moves inward relative to the outer cylinder portion 32. As a result, the inner bent portion 33b of the leg portion 33 approaches the outer bent portion 33c, the extended portion 33a is pushed in, and the leg portion 33 deforms so that its cross-section along the axial direction L becomes approximately S-shaped.

[0030] Furthermore, as shown in Figure 5, when the mass member 20 moves inward relative to the side plate 12 of the bracket 10, and the inner bent portion 33b moves inward beyond the outer bent portion 33c, the extended portion 33a flips over, and the leg portion 33 deforms into a nearly straight shape. The pull-out load applied to the rubber in the press-fit holding area S reaches its maximum value just before the extended portion 33a flips over.

[0031] In the dynamic damper 1 of this embodiment, as shown in Figure 4, a crank-shaped leg portion 33 is interposed between the inner cylinder portion 31 and the outer cylinder portion 32 of the rubber elastic body 30. When this leg portion 33 is pushed in the axial direction L and deformed, the pull-out load applied to the rubber in the press-fit holding region S can be effectively reduced. Furthermore, when the mass member 20 moves inward relative to the side plate 12 of the bracket 10, the deformation of the engaging portion 32a of the rubber elastic body 30 is suppressed, thereby maintaining the engaged state between the mounting hole 13 and the engaging portion 32a. As a result, in the dynamic damper 1 of this embodiment, the rubber elastic body 30 can be press-fitted and held in place by the bracket 10, preventing the rubber elastic body 30 from coming out of the bracket 10.

[0032] As described above, in the dynamic damper 1 of this embodiment, the rubber elastic body 30 can be assembled by press-fitting it into the bracket 10. This simplifies the assembly work of the dynamic damper 1 and, consequently, reduces the manufacturing cost of the dynamic damper 1.

[0033] In the dynamic damper 1 of this embodiment, as shown in Figure 3, a space is formed in the region where the rubber elastic body 30 is pressed against the mounting hole 13. In the configuration shown in Figure 3, even if the dimensions of the mounting hole 13 vary within tolerance for each product, and the press-fitting allowance of the rubber elastic body 30 relative to the mounting hole 13 is not uniform, the variation in the spring characteristics of the rubber elastic body 30 can be reduced, thereby stabilizing the quality of the dynamic damper 1.

[0034] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from its spirit. In the dynamic damper 1 of this embodiment, as shown in Figure 3, the press-fit holding area S and the leg portion 33 are aligned without overlapping in the axial direction L. However, a part of the leg portion 33 may be inserted into the press-fit holding area S so that the press-fit holding area S and the leg portion 33 are aligned. Furthermore, the entire leg portion 33 may be inserted into the press-fit holding area S.

[0035] In the dynamic damper 1 of this embodiment, as shown in Figure 2, the mass member 20 is supported by two rubber elastic bodies 30, 30, but it may also be configured to support the mass member 20 by one or more rubber elastic bodies 30.

[0036] The dynamic damper 1 of this embodiment is attached to the back door of an automobile, but the vibrating member to which the dynamic damper of the present invention can be attached is not limited, and it can be attached to any component that generates vibration in various devices. [Explanation of symbols]

[0037] 1. Dynamic damper 10 brackets 11 Mounting plate 11a Connection hole 12 Side panels 13 mounting holes 13a Edge 20 Mass Members 21 Main body 21a End face 22 Shaft section 22a Rib 30 Rubber elastic material 31 Inner cylinder 32 Outer cylinder 32a Engagement part 32b Fitting part 32c Stopper part 33 Legs 33a Extension 33b Inner folded portion 33c Outer folded section B bolt S Press-fit holding area

Claims

1. A bracket with mounting holes formed therein, A rubber elastic body is press-fitted into the aforementioned mounting hole, It has a mass member supported by the rubber elastic body, The rubber elastic body is An inner cylinder portion fitted to the outer circumferential surface of the aforementioned mass member, The outer cylinder portion fitted to the inner circumferential surface of the aforementioned mounting hole, It comprises a leg portion interposed between the outer circumferential surface of the inner cylinder portion and the inner circumferential surface of the outer cylinder portion, The leg portion has an extended portion that extends in the axial direction of the rubber elastic body. In the extended portion, an inner bent portion is formed at one end in the axial direction, which is connected to the outer circumferential surface of the inner cylinder portion. A dynamic damper characterized in that an outer bent portion is formed at the other end of the extended portion in the axial direction, and is connected to the inner circumferential surface of the outer cylinder portion.

2. A dynamic damper according to claim 1, A press-fit holding region is provided in which the press-fit contact region between the mass member and the inner cylinder portion and the press-fit contact region between the mounting hole and the outer cylinder portion overlap with a gap in the radial direction of the rubber elastic body. A dynamic damper characterized in that the press-fit holding region and the leg portion are arranged in the axial direction.

3. A dynamic damper according to claim 2, The outer cylinder portion has an engaging portion that engages with the edge of the mounting hole. A dynamic damper characterized in that the press-fit holding region is provided between the engagement portion and the leg portion.

Images