Dynamic damper

Abstract

A dynamic damper 10 that is attached to a mounting member is provided with: a first weight 20 and a second weight 22 that are provided so as to be able to vibrate; and an elastic body supporting the first weight 20 and the second weight 22 so as to be able to vibrate. The elastic body 18 has a first holding section holding the first weight 20; a second holding section holding the second weight 22; a first elastic section extending from the first holding section to the second holding section and connecting the first weight 20 and the second weight 22; and a second elastic section extending from the second holding section to the mounting member and connecting the second weight 22 and the mounting member. The elastic body 18 integrally forms the first holding section, the second holding section, the first elastic section, and the second elastic section, and is provided as a pair of elastic bodies.

Description

Technical Field

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

Background Art

[0002] When a seat device on which an occupant sits or a headrest that supports the head of the occupant resonates due to vibrations during driving or idling, etc., the riding comfort of the occupant may deteriorate.

[0003] In Patent Document 1, a headrest provided at the upper part of a seat back includes a stay forming the skeleton of the headrest, front and rear panels that sandwich a part of the stay and form a space inside and are joined at the outer periphery, a pad that covers the part of the stay and the front and rear panels, and a dynamic damper disposed in the space. This dynamic damper has a weight, and an elastic member that holds the weight and has an upper column portion and a lower column portion that extend in a direction away from the weight.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the dynamic damper described in Patent Document 1, the weight vibrates to exhibit a function of suppressing a specific resonance. However, vibrations may occur at a plurality of resonance points in a vehicle, and it is desirable to be able to exhibit a function of suppressing vibrations with respect to the plurality of resonance points.

[0006] An object of the present invention is to provide a dynamic damper that suppresses vibrations with respect to a plurality of resonance points.

Means for Solving the Problems

[0007] To solve the above problems, one aspect of the present invention provides a dynamic damper attached to a mounting member, comprising a first weight and a second weight that are vibrably provided, and an elastic body that vibrably supports the first weight and the second weight. The elastic body has a first holding portion for holding the first weight, a second holding portion for holding the second weight, a first elastic portion extending from the first holding portion to the second holding portion and connecting the first weight and the second weight, and a second elastic portion extending from the second holding portion to the mounting member and connecting the second weight and the mounting member. The elastic body is formed integrally with the first holding portion, the second holding portion, the first elastic portion and the second elastic portion, and is provided in pairs.

[0008] Another aspect of the present invention is a dynamic damper attached to a mounting member. This dynamic damper comprises a first weight and a second weight that are vibratably mounted, a first elastic section connecting the first weight and the second weight, and a second elastic section connecting the second weight and the mounting member. The first elastic section is provided in a pair and arranged coaxially, and the second elastic section is provided in a pair and arranged coaxially. [Effects of the Invention]

[0009] According to the present invention, a dynamic damper can be provided that suppresses vibrations at multiple resonance points. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the mounting structure of the dynamic damper. [Figure 2] This is a perspective view of a dynamic damper. [Figure 3] This is a perspective view of an elastic body. [Figure 4] This is a perspective view showing the mounting structure of the dynamic damper in the first modified example. [Figure 5] This is a perspective view of the dynamic damper in the second modification example. [Figure 6] This is a perspective view of the dynamic damper in the third variation example. [Modes for carrying out the invention]

[0011] Figure 1 is a perspective view of the mounting structure 1 for the dynamic damper. The dynamic damper 10 is attached to an in-vehicle component such as a headrest or seat system. The dynamic damper 10 generates vibrations that cancel out vibrations of the in-vehicle component in order to suppress resonance of the in-vehicle component.

[0012] The dynamic damper 10 is housed inside the mounting member 14 and attached to the frame 12 via the mounting member 14. The frame 12 is the frame of the headrest or seat. The mounting member 14 forms a housing space for the dynamic damper 10, and although Figure 1 shows it open and the dynamic damper 10 exposed, in reality the opening is closed with a cap (not shown).

[0013] The mounting member 14 has a plurality of hook portions 14a for hooking onto the frame 12 and a mounting base portion 14b for fixing the dynamic damper 10. The mounting base portion 14b has an opening for fixing the dynamic damper 10. The mounting member 14 houses the dynamic damper 10 and attaches the dynamic damper 10 to the frame 12. The mounting member 14 may be screwed to the frame 12 instead of using the hook portions 14a. The dynamic damper 10 may also be attached directly to the frame 12 without using the mounting member 14.

[0014] Figure 2 is a perspective view of the dynamic damper 10. The dynamic damper 10 comprises a pair of elastic bodies 18 and a first weight 20 and a second weight 22. The elastic bodies 18 are made of a flexible resin material, such as rubber. The first weight 20 and the second weight 22 are made of a metal material.

[0015] The first weight 20 is formed in a cylindrical shape. The shape of the first weight 20 is not limited to a cylindrical shape and may be a prismatic shape. The second weight 22 is a rectangular frame and is formed in an annular shape. The first weight 20 is disposed inside the second weight 22. The weight of the first weight 20 may be the same as that of the second weight 22, but may be larger than that of the second weight 22. That is, the weight of the first weight 20 is set to be not less than the weight of the second weight 22. The first weight 20 and the second weight 22 are supported by the elastic body 18 so as to be vibratable.

[0016] The elastic body 18 has a first elastic portion 24, a second elastic portion 26, a first holding portion 28, a second holding portion 30, and a fixing portion 32. The pair of elastic bodies 18 have the same shape and are arranged coaxially. The elastic body 18 will be described while referring to FIG. 3.

[0017] FIG. 3 is a perspective view of the elastic body 18. The first holding portion 28 holds the first weight 20. The first holding portion 28 is formed in a substantially cup shape, formed at one end of the first elastic portion 24, and engages with one end of the first weight 20. One end of the first weight 20 is inserted into the first holding portion 28 and engages with the first holding portion 28. A slit 28a is formed at the corner edge of the first holding portion 28, and the degree of insertion of the first weight 20 can be confirmed.

[0018] The second holding portion 30 is formed between the first elastic portion 24 and the second elastic portion 26 and holds the second weight 2^{2}. The second holding portion 30 surrounds the short side portion of the second weight 22 and is formed in a cylindrical shape. The second holding portion 30 is formed in a rectangular tubular shape, but may have a shape adapted to the shape of the second weight 22. If the second weight 22 has a circular cross section, the second holding portion 30 is formed in a cylindrical shape.

[0019] The fixing portion 32 is formed at one end of the second elastic portion 26 and is fixed to the mounting pedestal portion 14b. The fixing portion 32 is fixed by being hooked on the opening edge of the mounting pedestal portion 14b. Note that the fixing portion 32 may be fixed to the mounting pedestal portion 14b by welding or adhesion. Also, the first holding portion 28 and the second holding portion 30 may hold the first weight 20 or the second weight 22 by welding or adhesion.

[0020] The first elastic part 24 is formed in a cylindrical shape, extends from the first holding part 28 to the second holding part 30, and connects the first weight 20 and the second weight 22. The first elastic part 24 extends so as to be easily bent and vibrates the first weight 20.

[0021] The second elastic part 26 is formed in a prismatic shape, extends from the second holding part 30 to the mounting pedestal part 14b, and connects the second weight 22 and the mounting member 14. The second elastic part 26 extends in the same manner as the first elastic part 24 and vibrates the first weight 20 and the second weight 22.

[0022] The vibrations of the first weight 20 and the second weight 22 act to cancel out the vibrations of the frame 12, suppressing the vibrations of the frame 12. Since the first weight 20 and the second weight 22 can vibrate individually, one dynamic damper 10 can exhibit the effect of suppressing vibrations for two resonance points.

[0023] The elastic body 18 is formed integrally with the first holding part 28, the second holding part 30, the first elastic part 24, and the second elastic part 26. As a result, the molding process is reduced, and the manufacturing cost of the dynamic damper 10 can be suppressed.

[0024] As shown in FIG. 3, the first elastic part 24 and the second elastic part 26 are coaxially arranged along the central axis A. Since the first elastic part 24 and the second elastic part 26 are coaxial, it is easy to integrally mold them at positions sandwiching the second holding part 30, and it becomes easy to mold the center of gravity positions of the first weight 20 and the second weight 22 to coincide. Also, based on the coaxial first elastic part 24 and second elastic part 26, the resonance points of the first weight 20 and the second weight 22 can be determined, and it is easy to set the respective resonance points.

[0025] As shown in FIG. 2, the first weight 20 and the second weight 22 are arranged such that the positions of the centers of gravity C are substantially the same. Thereby, it becomes easy to set two resonance points due to the vibrations of the first weight 20 and the second weight 22.

[0026] As shown in Figure 2, the first weight 20 is positioned inside the annularly formed second weight 22. This makes it easy to align the center of gravity C of the first weight 20 and the second weight 22. Furthermore, the dynamic damper 10 can be miniaturized by being configured as a single unit.

[0027] The first elastic portion 24 and the second elastic portion 26 are formed with different cross-sectional shapes when cut in a direction perpendicular to the extension direction. The extension direction is along the central axis A of the first elastic portion 24 and the second elastic portion 26. The cross-section of the first elastic portion 24 is circular, and the cross-section of the second elastic portion 26 is rectangular. This difference in cross-sectional shape makes it possible to make the vibration directions of the first weight 20 and the second weight 22 different. In particular, by making the cross-section of the first weight 20 or the second weight 22 rectangular, the direction in which it is prone to vibration can be limited.

[0028] Because the cross-section of the first weight 20 is circular, the first weight 20 is prone to vibration in any radial direction. On the other hand, the second weight 22 is less prone to vibration in the diagonal direction of its cross-section. As a result, the first weight 20, which suppresses vibration in all directions, acts as the main vibration suppressor, while the second weight 22 acts secondarily to suppress vibration in limited directions. Since the first weight 20 can vibrate due to the deflection of both the first elastic part 24 and the second elastic part 26, it begins to vibrate before the second weight 22 and transmits that vibration to the second weight 22.

[0029] The axial length of the first elastic section 24 may be longer than the axial length of the second elastic section 26. This makes the first elastic section 24 more flexible than the second elastic section 26. Thus, the elastic modulus of the first elastic section 24 may be set to be smaller than that of the second elastic section 26. Also, the weight of the first weight 20 may be set to be greater than or equal to the weight of the second weight 22. This makes the first weight 20 more likely to vibrate at a lower resonance point. As the frequency increases, the vibration of the first weight 20 alone decreases, while the first weight 20 and the second weight 22 begin to vibrate together, making them more likely to vibrate at a higher resonance point.

[0030] Figure 4 is a perspective view showing the mounting structure of the dynamic damper 100 in the first modified example. The dynamic damper 100 shown in Figure 4 has a different mounting structure to the frame 12 compared to the dynamic damper 10 shown in Figure 1. In the dynamic damper 10 shown in Figure 1, the central axis of the first weight 20 is positioned along the vertical direction, whereas in the dynamic damper 100 shown in Figure 4, the central axis of the first weight 20 is positioned along the left-right direction of the vehicle.

[0031] The dynamic damper 100 is attached to the mounting member 114. The mounting member 114 is a bracket, formed by bending a plate material, and is fixed to the seat by screws while in contact with the frame 12.

[0032] The dynamic damper 100 comprises a first weight 20, a second weight 22, and an elastic body 118. The elastic body 118 shown in Figure 4 differs from the elastic body 18 shown in Figure 3 in the shape of its fixing portion 132. One end of the second elastic portion 26 of the elastic body 118 functions as the fixing portion 132 and is fixed to the mounting member 114.

[0033] Figure 5 is a perspective view of the dynamic damper 200 of the second modification example. The dynamic damper 200 shown in Figure 5 is shown attached to the mounting member 214. The dynamic damper 200 has a different elastic body shape compared to the dynamic damper 10 shown in Figure 1. The dynamic damper 200 comprises a first weight 20, a second weight 22, a pair of first elastic bodies 218a, and a pair of second elastic bodies 218b.

[0034] The first elastic body 218a has a first elastic portion 24, a first retaining portion 28, and a second retaining portion 230a. The first retaining portion 28 is connected to one end of the first elastic portion 24, and the second retaining portion 230a is connected to the other end of the first elastic portion 24. The second retaining portion 230a surrounds the short side of the second weight 22 and is formed in a cylindrical shape. Alternatively, the second retaining portion 230a may be omitted, and the first elastic portion 24 may be directly connected to the second weight 22 by adhesive.

[0035] The first elastic section 24 extends from the first holding section 28 to the second holding section 230a, connecting the first weight 20 and the second weight 22. As a result, the first weight 20 vibrates relative to the second weight 22 and the mounting member 214. The pair of first elastic bodies 218a are arranged coaxially along the axial direction of the first elastic section 24. In other words, the pair of first elastic sections 24 are arranged coaxially.

[0036] The second elastic body 218b has a second elastic portion 226 and a third retaining portion 230b. The third retaining portion 230b surrounds the long side of the second weight 22 and is formed in a cylindrical shape. Alternatively, the third retaining portion 230b may be omitted, and the second elastic portion 226 may be directly connected to the second weight 22 by adhesive. The second elastic portion 226 extends from the third retaining portion 230b to the mounting member 214, and the second elastic portion 226 connects the second weight 22 and the mounting member 214.

[0037] The pair of second elastic bodies 218b are arranged coaxially along the axial direction of the second elastic portion 226, and the pair of second elastic portions 226 are arranged coaxially. In this way, the first elastic portion 24 and the second elastic portion 226 are arranged in orthogonal directions. The first elastic portion 24 is formed in a cylindrical shape, and the second elastic portion 226 is formed in a prismatic shape. In other words, the cross-sectional shapes of the first elastic portion 24 and the second elastic portion 226 are different. The elastic modulus of the first elastic portion 24 may be smaller than that of the second elastic portion 226.

[0038] The dynamic damper 200 can suppress vibrations at two resonance points by the vibration of the first weight 20 and the second weight 22. The first weight 20 tends to vibrate in a direction perpendicular to its axis. The second weight 22 tends to vibrate in a direction perpendicular to the plane surrounding the second weight 22 and in the axial direction of the first weight 20. Since the first elastic body 218a and the second elastic body 218b are arranged separately, the connection positions to the first weight 20 and the second weight 22 can be freely set, making it easy to set the damper to suppress desired vibrations.

[0039] Figure 6 is a perspective view of the dynamic damper 300 of the third modification example. The dynamic damper 300 shown in Figure 6 has a different shape of elastic body 318 compared to the dynamic damper 10 shown in Figure 1.

[0040] The elastic body 318 has a first elastic portion 24, a second elastic portion 26, a first holding portion 328, a second holding portion 30, and a fixing portion 32. The first holding portion 328 has a cylindrical portion that covers the outer circumference of the first weight 20 and two disc portions that cover both ends of the first weight 20. The first holding portion 328 has a slit 328a with some corners cut out. The elastic body 318 is composed of a single unit by providing the first holding portion 328 to cover the entire outer circumference of the first weight 20.

[0041] The present invention is not limited to the embodiments described above, and various modifications such as design changes can be made to each embodiment based on the knowledge of those skilled in the art, and embodiments with such modifications may also be included within the scope of the present invention.

[0042] Although the first elastic portion 24 is shown as cylindrical and the second elastic portion 26 as prismatic, the design is not limited to these shapes. For example, the first elastic portion 24 may be prismatic and the second elastic portion 26 as cylindrical. Alternatively, the first elastic portion 24 may be hexagonal and the second elastic portion 26 as square. In any case, the cross-sectional shapes of the first elastic portion 24 and the second elastic portion 26 are different, and the directions in which the first weight 20 and the second weight 22 are prone to vibration are different. The cross-sectional shapes of the first elastic portion 24 and the second elastic portion 26 are also the same.

[0043] Furthermore, although the embodiment shows a configuration in which the centers of gravity of the first weight 20 and the second weight 22 are at the same position, the embodiment is not limited to this configuration, and the centers of gravity may be offset from each other. Also, although the embodiment shows a configuration in which the weight of the first weight 20 is greater than the weight of the second weight 22, the embodiment is not limited to this configuration, and the weight of the first weight 20 may be less than the weight of the second weight 22. [Industrial applicability]

[0044] This invention relates to a dynamic damper that suppresses vibrations. [Explanation of Symbols]

[0045] 10 Dynamic damper, 12 Frame, 14 Mounting member, 14a Hook part, 14b Mounting base part, 18 Elastic body, 20 First weight, 22 Second weight, 24 First elastic part, 26 Second elastic part, 28 First holding part, 28a Slit, 30 Second holding part, 32 Fixing part.

Claims

1. A dynamic damper that is attached to a mounting member, A first weight and a second weight are provided to be vibrable, The system comprises an elastic body that vibratesly supports the first weight and the second weight, The elastic body is The first holding part that holds the first weight, The second holding part holds the second weight, A first elastic portion extends from the first holding portion to the second holding portion and connects the first weight and the second weight, It has a second elastic portion that extends from the second holding portion to the mounting member and connects the second weight and the mounting member, The dynamic damper is characterized in that the elastic body is formed integrally with the first retaining portion, the second retaining portion, the first elastic portion, and the second elastic portion, and is provided in pairs.

2. The dynamic damper according to claim 1, characterized in that the first elastic portion and the second elastic portion are arranged coaxially.

3. The dynamic damper according to claim 1 or 2, characterized in that the first weight and the second weight are arranged such that their centers of gravity are substantially the same.

4. The second weight is formed in an annular shape, The dynamic damper according to claim 1 or 2, characterized in that the first weight is positioned inside the second weight.

5. The dynamic damper according to claim 1 or 2, characterized in that the first elastic portion and the second elastic portion are formed to have different cross-sectional shapes when cut in a direction perpendicular to the extension direction.

6. A dynamic damper that is attached to a mounting member, A first weight and a second weight are provided to be vibrable, A first elastic portion connecting the first weight and the second weight, The device comprises a second elastic portion connecting the second weight and the mounting member, The first elastic portion is provided in a pair and arranged coaxially, The dynamic damper is characterized in that the second elastic portion is provided in a pair and arranged coaxially.

Images