Vibration damping device and vehicle seat equipped with the vibration damping device

Abstract

To deal with multiple resonance frequencies of a seat with one vibration damping device.SOLUTION: A vibration damping device 40 includes: a shoulder bolt 42 attached to a seat frame 10A; an inner weight member 46 which has a first through hole 46A, into which the shoulder bolt 42 is inserted, and may move along an axial direction D of the shoulder bolt 42; an outer weight member 50 which has a second through hole 50A, into which the shoulder bolt 42 is inserted, and may move along the axial direction D of the shoulder bolt 42; and an inner coil spring 48 and an outer coil spring 52 which are disposed at both sides of the inner weight member 46 and the outer weight member 50 in the axial direction D and allow the inner weight member 46 and the outer weight member 50 to vibrate separately.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vibration damping device and a vehicle seat equipped with the vibration damping device. [Background technology]

[0002] BACKGROUND ART It is known to provide a vibration damping device for damping vibrations of a seat in a vehicle or the like (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a technology in which a dynamic damper including a weight and an elastic member that supports the weight so that it can vibrate is provided with a movement restriction means that restricts movement of the weight in a predetermined direction. This allows the dynamic damper to restrict movement of the weight in the predetermined direction, thereby efficiently exerting a vibration-damping effect against vibrations in the specific direction that should originally be damped. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-111295 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique described in Patent Document 1 has a problem in that one vibration damping device cannot be adapted to multiple resonance frequencies of the seat.

[0006] In consideration of the above, the present invention aims to provide a vibration damping device that can accommodate multiple resonant frequencies of a seat with a single vibration damping device, and a vehicle seat equipped with this vibration damping device. [Means for solving the problem]

[0007] of the first aspectThe vibration damping device comprises an axle member attached to the seat frame, a plurality of weight members each having a through hole through which the axle member is inserted and movable along the axial direction of the axle member, and coil springs arranged on both sides of each of the weight members in the axial direction, allowing each of the weight members to vibrate separately.

[0008] First Aspect According to the document, by providing a plurality of weight members that can vibrate separately along the shaft member, each weight member can move independently on the same axis. Therefore, if the plurality of weight members are set to have different natural frequencies, the vibration damping device is set to have multiple natural frequencies. As a result, one vibration damping device can accommodate multiple resonant frequencies of the seat.

[0009] of the second aspect In vibration damping devices, First Aspect In the vibration damping device of the present invention, the weight member comprises an annular inner weight member having a first through hole through which the shaft member is inserted, and an annular outer weight member having a second through hole through which the inner weight member is inserted, and the coil spring comprises inner coil springs arranged on both sides of the inner weight member in the axial direction so as to surround the outer periphery of the shaft member, and outer coil springs arranged on both sides of the outer weight member in the axial direction so as to surround the outer periphery of the inner coil spring.

[0010] Second Aspect According to the document, the vibration damping device includes an inner weight member through which a shaft member is inserted and in which inner coil springs are arranged on both axial sides, and an outer weight member through which the inner weight member is inserted and in which outer coil springs are arranged on both axial sides, thereby enabling the inner weight member and the outer weight member to operate independently. Therefore, when the inner weight member and the outer weight member are set to have different natural frequencies, the vibration damping device is set to have two natural frequencies. As a result, one vibration damping device can accommodate two resonant frequencies of the seat.

[0011] of the third aspect In vibration damping devices, Second AspectIn the vibration damping device of the above, the outer peripheral surface of the shaft member is covered with a collar member made of resin, and the outer peripheral surface of the inner weight member is covered with a lubricating layer.

[0012] Third Aspect According to the present invention, the outer circumferential surface of the shaft member is covered with a resin collar member, thereby interposing the resin collar member between the shaft member and the inner weight member. Therefore, noise generated between the shaft member and the inner weight member can be suppressed. Furthermore, the outer circumferential surface of the inner weight member is covered with a lubricating layer, thereby interposing the lubricating layer between the inner weight member and the outer weight member. Therefore, noise generated between the inner weight member and the outer weight member can be suppressed.

[0013] The fourth aspect In vibration damping devices, First Aspect from Third Aspect Any one of One aspect In the vibration damping device of the above, the coil spring is arranged in a compressed state.

[0014] Fourth Aspect According to the document, by disposing the coil springs in a compressed state, when the weight member moves along the shaft member, one coil spring is further compressed, while the other coil spring is expanded but maintained in a compressed state. Therefore, when the weight member vibrates, the coil springs are always in contact with the weight member. As a result, abnormal noise generated between the weight member and the coil springs can be suppressed.

[0015] The fifth aspect In vehicle seats, First Aspect from Fourth Aspect One of One aspect The vibration damping device is provided on a seat back that supports the upper body of a seated occupant or on a headrest that supports the head of a seated occupant.

[0016] Fifth Aspect According to the present invention, by providing a vibration damping device on the seat back or headrest, which vibrates more than the seat cushion side, the vibration energy of the vehicle seat can be effectively absorbed, and the damping efficiency for damping the vibration of the vehicle seat can be improved.

[0017] The sixth aspect In vehicle seats, Fifth Aspect In the vehicle seat, the natural frequencies of the weight members are different from one another and are set to be the same as any of a plurality of resonance frequencies of the vehicle seat.

[0018] Sixth Aspect According to the present invention, the natural frequencies of the weight members are different from each other and are set to be the same as any one of a plurality of resonance frequencies of the vehicle seat, thereby making it possible to correspond to the plurality of resonance frequencies of the vehicle seat.

[0019] of the seventh aspect In vehicle seats, Fifth Aspect or Sixth Aspect In the vehicle seat of the above, the vibration damping device is provided on the upper end side of a seat back frame that constitutes the framework of the seat back.

[0020] Seventh aspect According to the present invention, by providing the vibration damping device on the upper end side of the seat back frame that constitutes the framework of the seat back, it is possible to ensure sufficient space for installing the vibration damping device.

[0021] of the eighth aspect In vehicle seats, Fifth Aspect from Seventh aspect Any one of One aspect In the vehicle seat of the above, the shaft member is disposed along the seat width direction.

[0022] Eighth aspect According to the present invention, by installing the shaft member along the seat width direction, vibrations of the vehicle seat along the seat width direction can be damped.

[0023] The ninth aspect In vehicle seats, Fifth Aspect from Eighth aspect Any one of One aspect In the vehicle seat of the above, the shaft member is installed along the front-rear direction of the seat.

[0024] Ninth aspect According to the present invention, by installing the shaft member along the seat front-rear direction, vibrations of the vehicle seat along the seat front-rear direction can be damped.

[0025] of the tenth aspect In vehicle seats, Fifth Aspect from Ninth aspect Any one of One aspect In the vehicle seat of the above, the shaft member is installed so as to have components in the seat width direction, the seat front-rear direction, and the seat up-down direction.

[0026] Tenth Aspect According to the present invention, by installing the shaft member so that it includes components in the seat width direction, the seat front-rear direction, and the seat up-down direction, it is possible to damp vibrations of the vehicle seat that include components in the seat width direction, the seat front-rear direction, and the seat up-down direction. [Effects of the Invention]

[0027] According to the vibration damping device of the present invention, one vibration damping device can be adapted to a plurality of resonance frequencies of the seat. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective view of a vehicle seat according to a first embodiment, viewed from diagonally forward left of the seat. [Figure 2] 1 is a perspective view of a seat frame of a vehicle seat according to a first embodiment, viewed from diagonally forward left of the seat. [Figure 3] 1 is a perspective view showing a state in which a vibration damping device according to a first embodiment is attached to a bracket attached to a seat frame. [Figure 4] 1 is an exploded perspective view showing a vibration damping device according to a first embodiment. [Figure 5] 4 is a cross-sectional view showing the vibration damping device according to the first embodiment, showing the cross section taken along the line AA in FIG. 3. FIG. [Figure 6] FIG. 2 is a schematic diagram showing a vibration model of the vibration damping device according to the first embodiment. [Figure 7] 7A and 7B are cross-sectional views illustrating the operation of the vibration damping device according to the first embodiment, in which FIG. 7A shows a state in which the inner weight member has moved to one end side, and FIG. 7B shows a state in which the inner weight member has moved to the other end side. [Figure 8] 8A and 8B are cross-sectional views illustrating the operation of the vibration damping device according to the first embodiment, in which FIG. 8A shows a state in which the outer weight member has moved to one end side, and FIG. 8B shows a state in which the outer weight member has moved to the other end side. [Figure 9] FIG. 6 is a side view showing a vibration damping device according to a second embodiment. [Figure 10] FIG. 10 is a side view showing a vibration damping device according to a third embodiment. [Figure 11] FIG. 10 is a perspective view showing a state in which a vibration damping device according to another embodiment is attached to a bracket attached to a seat frame. [Figure 12] FIG. 10 is a perspective view showing a state in which a vibration damping device according to another embodiment is attached to a bracket attached to a seat frame. DETAILED DESCRIPTION OF THE INVENTION

[0029] [First embodiment] The vibration damping device according to the first embodiment will be described below with reference to the drawings. In each drawing, the arrow FR indicates the front in the seat longitudinal direction, the arrow UP indicates the upper side in the seat vertical direction, and the arrow RH indicates the right side in the seat width direction. The arrow D indicates the axial direction of the shoulder bolt. Hereinafter, when the directions of the front-rear, up-down, and left-right are used in the description, they refer to the front-rear, up-down, and left-right of the vehicle seat when facing the vehicle seat in the direction of travel, unless otherwise specified. When the directions of the one end and the other end are used in the description, they refer to the axial direction of the shoulder bolt, unless otherwise specified. The headrest stay of the headrest, which constitutes the seat frame, is not shown in FIG. 2.

[0030] The vibration damping device of the first embodiment will be described as being applied to a vehicle seat provided in a vehicle.

[0031] [Vehicle seat configuration] 1 and 2, the vehicle seat 10 includes a seat cushion 12 on which an occupant sits, a seat back 14 that supports the upper body of the occupant, a headrest 16 that is provided above the seat back 14 and supports the head of the occupant, and a seat frame 10A that forms the framework of the vehicle seat 10. The seat frame 10A includes a cushion frame 18 and a seat back frame 28.

[0032] The seat cushion 12 is formed of a foam material such as a urethane pad, and is fixed to a cushion frame 18 shown in FIG.

[0033] 2, slide rails 20 extending along the front-rear direction of the seat are provided below both ends of the cushion frame 18 in the seat width direction. The pair of left and right slide rails 20 are fixed to a vehicle body floor 26 via front seat brackets 22 provided at the front of the slide rails 20 and rear seat brackets 24 provided at the rear of the slide rails 20. The vehicle seat 10 is slidable along the front-rear direction of the vehicle via the pair of left and right slide rails 20.

[0034] As shown in FIG. 1, the seat back 14, like the seat cushion 12, is formed of a foam material such as a urethane pad, and is fixed to a seat back frame 28 shown in FIG.

[0035] 2, the seatback frame 28 includes a lower frame 25 disposed below the seatback frame 28 and an upper frame 27 disposed above the seatback frame 28. The lower frame 25 is provided with a reclining device 29 that enables the seatback frame 28 to be tilted in the longitudinal direction of the vehicle relative to the cushion frame 18. A headrest stay (not shown) of the headrest 16 is connected to the upper frame 27. The lower frame 25 and the upper frame 27 are connected via a plurality of bolts 32.

[0036] 2, a vibration damping device 40 is attached to a metal bracket 34 that is attached by a mounting bracket or the like (not shown) to an upper end member 27A that forms the upper end of the upper frame 27. The vibration damping device 40 is provided approximately in the center in the seat width direction.

[0037] As shown in FIG. 3, the bracket 34 is formed in an L-shape and has a first piece 34A extending in the seat width direction and a second piece 34B extending in the seat front-rear direction.

[0038] [Configuration of vibration damping device] As shown in FIG. 4, the vibration damping device 40 includes a shoulder bolt 42 as an axial member, a collar member 44, an inner weight member 46 as a weight member, an inner coil spring 48 as a coil spring, an outer weight member 50 as a weight member, an outer coil spring 52 as a coil spring, and a base plate 54.

[0039] (Shoulder bolt 42) As shown in Figures 4 and 5, the shoulder bolt 42 is made of metal and has a shaft portion 42A, a male thread portion 42C formed on one end side of the shaft portion 42A, and a head portion 42B formed on the other end side of the shaft portion 42A.

[0040] The shaft portion 42A is formed in a cylindrical shape. The male threaded portion 42C is cylindrical and has an outer diameter smaller than that of the shaft portion 42A, and has a screw thread formed on its outer peripheral surface. The head portion 42B is cylindrical and has an outer diameter larger than that of the shaft portion 42A. A tool hole 42D for a tool (e.g., a hexagonal wrench) used to attach the male threaded portion 42C to a nut 43 (described later) is formed on the surface on the other end side of the head portion 42B.

[0041] (Collar material 44) The collar member 44 is disposed radially outward of the shank 42A of the shoulder bolt 42. The collar member 44 is made of resin and is formed in a cylindrical shape. The inner diameter of the collar member 44 is formed to be approximately the same as the outer diameter of the shank 42A. The shank 42A of the shoulder bolt 42 is inserted into the collar member 44, and the outer peripheral surface of the shank 42A is covered by the collar member 44. In other words, the collar member 44 is interposed between the inner weight member 46 and the shank 42A. The collar member 44 is also interposed between the shank 42A and the inner coil spring 48.

[0042] (Inner weight member 46) The inner weight member 46 is disposed radially outward of the collar member 44. The inner weight member 46 is made of metal and formed into a cylindrical shape. The inner weight member 46 has a first through hole 46A through which the shoulder bolt 42 and the collar member 44 are inserted. The inner diameter of the first through hole 46A is formed to be approximately the same as the outer diameter of the collar member 44. The inner weight member 46 is configured to be movable in the axial direction D along the collar member 44.

[0043] (Inner coil spring 48) The inner coil spring 48 is disposed radially outside the collar member 44. The inner coil spring 48 is formed to a size that allows the shoulder bolt 42 and the collar member 44 to be inserted inside. The outer diameter of the inner coil spring 48 is formed to be larger than the inner diameter of the inner weight member 46. The inner coil spring 48 includes a first inner coil spring 48A and a second inner coil spring 48B.

[0044] The first inner coil spring 48A is disposed on the other end side of the inner weight member 46. In a compressed state, the first inner coil spring 48A is disposed between an end face on the other end side of the inner weight member 46 and an end face on one end side of the head 42B. The first inner coil spring 48A is disposed so as to surround the outer periphery of the collar member 44.

[0045] The second inner coil spring 48B is disposed on one end side of the inner weight member 46. In a compressed state, the second inner coil spring 48B is disposed between an end face on one end side of the inner weight member 46 and an end face on the other end side of the base plate 54 attached to the male thread portion 42C of the shoulder bolt 42. The second inner coil spring 48B is disposed so as to surround the outer periphery of the collar member 44.

[0046] The inner weight member 46 is biased toward one end by the first inner coil spring 48A and toward the other end by the second inner coil spring 48B. Elastic energy (biasing force) is accumulated in the first inner coil spring 48A and the second inner coil spring 48B. As a result, the inner weight member 46 is disposed at approximately the center in the axial direction D of the shank 42A of the shoulder bolt 42. In other words, the inner weight member 46 is subjected to so-called forced vibration, in which the biasing forces of the first inner coil spring 48A and the second inner coil spring 48B act.

[0047] (Outer weight member 50) The outer weight member 50 is disposed radially outward of the inner weight member 46. The outer weight member 50 is made of metal and formed into a cylindrical shape. The outer weight member 50 has a second through hole 50A through which the inner weight member 46 is inserted. The inner diameter of the second through hole 50A is formed to be approximately the same as the outer diameter of the inner weight member 46. The length in the axial direction D of the outer weight member 50 can be approximately the same as the length in the axial direction D of the inner weight member 46. Note that the length in the axial direction D of the outer weight member 50 may be shorter or longer than the length in the axial direction D of the inner weight member 46.

[0048] Grease G is interposed between the outer weight member 50 and the inner weight member 46 as a lubricating layer. In other words, the outer peripheral surface of the inner weight member 46 is covered with grease G as a lubricating layer. The outer weight member 50 is configured to be movable in the axial direction D along the inner weight member 46. Note that the outer peripheral surface of the collar member 44 may also be covered with grease G as a lubricating layer.

[0049] (Outer coil spring 52) The outer coil spring 52 is disposed radially outside the inner coil spring 48. The outer coil spring 52 is formed to a size that allows the inner coil spring 48 to be inserted inside. The outer diameter of the outer coil spring 52 is formed to be larger than the inner diameter of the outer weight member 50. The outer coil spring 52 includes a first outer coil spring 52A and a second outer coil spring 52B.

[0050] The first outer coil spring 52A is disposed on the other end side of the outer weight member 50. In a compressed state, the first outer coil spring 52A is disposed between an end face on the other end side of the outer weight member 50 and an end face on one end side of the head 42B. The first outer coil spring 52A is disposed so as to surround the outer periphery of the first inner coil spring 48A.

[0051] The second outer coil spring 52B is disposed on one end side of the outer weight member 50. In a compressed state, the second outer coil spring 52B is disposed between an end face on one end side of the outer weight member 50 and an end face on the other end side of the base plate 54 attached to the male thread portion 42C of the shoulder bolt 42. The second outer coil spring 52B is disposed so as to surround the outer periphery of the second inner coil spring 48B.

[0052] The outer weight member 50 is biased toward one end by the first outer coil spring 52A and toward the other end by the second outer coil spring 52B. Elastic energy (biasing force) is accumulated in the first outer coil spring 52A and the second outer coil spring 52B. As a result, the outer weight member 50 is disposed at approximately the center in the axial direction D of the shank 42A of the shoulder bolt 42. In other words, the outer weight member 50 is subjected to so-called forced vibration, with the biasing forces of the first outer coil spring 52A and the second outer coil spring 52B acting on it.

[0053] (Base plate 54) A base plate 54 is attached to the male threaded portion 42C of the shoulder bolt 42. The base plate 54 is formed in a cylindrical shape with an outer diameter larger than that of the outer coil spring 52. A screw hole 54A is formed in the base plate 54, penetrating through the plate thickness direction and having a female thread formed on the inner circumferential surface. The male threaded portion 42C of the shoulder bolt 42 is adapted to be fitted into the screw hole 54A of the base plate 54.

[0054] 3, the vibration damping device 40 formed in this manner is attached to the bracket 34 by attaching a nut 43 to the male thread portion 42C of the shoulder bolt 42 via the second piece 34B. The vibration damping device 40 is attached to the bracket 34 so that the axial direction D of the shoulder bolt 42 is aligned with the seat width direction. The vibration damping device 40 is attached via the bracket 34 to an upper end member 27A that is arranged on the upper end side of the seat frame 10A.

[0055] The vibration damping device 40 may also be provided on a headrest stay (not shown) of the headrest 16 that supports the head of a seated occupant.

[0056] [Natural frequency of weight member] The natural frequency of the inner weight member 46 and the natural frequency of the outer weight member 50 are set to be different from each other. The natural frequency of the inner weight member 46 is set to be the same as one of the two resonant frequencies of the vehicle seat 10. The natural frequency of the outer weight member 50 is set to be the same as the other of the two resonant frequencies of the vehicle seat 10.

[0057] 6, the spring constant k1 of the first inner coil spring 48A and the spring constant k2 of the second inner coil spring 48B are set so that one of the two resonant frequencies of the vehicle seat 10 is the same as the natural frequency of the inner weight member 46. For example, in free vibration, if the mass of the inner weight member 46 is M and the spring constant is k, the frequency (natural frequency) f of the inner weight member 46 can be calculated by equation (1). In the first embodiment, because forced vibration is used, the natural frequency f of the inner weight member 46 can be calculated by equation (2). In other words, the spring constant k1 of the first inner coil spring 48A and the spring constant k2 of the second inner coil spring 48B are set so that the natural frequency f of the inner weight member 46 is set to one of the two resonant frequencies of the vehicle seat 10.

[0058] Similarly, the spring constant k1 of the first outer coil spring 52A and the spring constant k2 of the second outer coil spring 52B are set so that the natural frequency f of the outer weight member 50 is set to the other of the two resonant frequencies of the vehicle seat 10.

[0059] [Operation of vibration damping device] When vibrations occur in the vehicle while idling or while driving, the vehicle seat 10 vibrates via the vehicle body floor portion 26. When the vehicle seat 10 vibrates at one of the resonant frequencies, as shown in FIG. 7(A), the inner weight member 46 moves along the collar member 44 toward one end in the axial direction D. At this time, the second inner coil spring 48B is compressed, and the first inner coil spring 48A is expanded but maintained in a compressed state. Next, as shown in FIG. 7(B), the inner weight member 46 moves along the collar member 44 toward the other end in the axial direction D. At this time, the first inner coil spring 48A is compressed, and the second inner coil spring 48B is expanded but maintained in a compressed state.

[0060] In this way, the first inner coil spring 48A and the second inner coil spring 48B cause the inner weight member 46 to reciprocate in the axial direction D along the collar member 44, thereby resonating. That is, vibration energy due to vibration of one of the resonant frequencies of the vehicle seat 10 is converted into kinetic energy that moves the inner weight member 46. As a result, the vibration energy due to vibration of one of the resonant frequencies of the vehicle seat 10 is absorbed, and the vibration of the vehicle seat 10 is damped.

[0061] When the vehicle seat 10 vibrates at the other resonant frequency, as shown in Fig. 8(A), the outer weight member 50 moves along the inner weight member 46 toward one end in the axial direction D. At this time, the second outer coil spring 52B is compressed, and the first outer coil spring 52A is expanded but maintained in a compressed state. Next, as shown in Fig. 8(B), the outer weight member 50 moves along the inner weight member 46 toward the other end in the axial direction D. At this time, the first outer coil spring 52A is compressed, and the second outer coil spring 52B is expanded but maintained in a compressed state.

[0062] In this way, the first outer coil spring 52A and the second outer coil spring 52B cause the outer weight member 50 to reciprocate along the inner weight member 46 in the axial direction D, thereby resonating. That is, vibrational energy due to vibration of the vehicle seat 10 at the other resonant frequency is converted into kinetic energy that moves the outer weight member 50. As a result, the vibrational energy due to vibration of the vehicle seat 10 at the other resonant frequency is absorbed, and the vibration of the vehicle seat 10 is damped. That is, the inner weight member 46 and the outer weight member 50 are configured to be able to vibrate separately.

[0063] [Actions and Effects of the First Embodiment] Next, the operation and effects of the vibration damping device 40 and the vehicle seat 10 of the first embodiment will be described.

[0064] The vibration damping device 40 of the first embodiment comprises a shoulder bolt 42 attached to the seat frame 10A, an inner weight member 46 having a first through hole 46A through which the shoulder bolt 42 is inserted and movable along the axial direction D of the shoulder bolt 42, and an outer weight member 50 having a second through hole 50A through which the shoulder bolt 42 is inserted and movable along the axial direction D of the shoulder bolt 42. The vibration damping device 40 further comprises an inner coil spring 48 and an outer coil spring 52 that are arranged on both sides of the inner weight member 46 and the outer weight member 50 in the axial direction D and that enable the inner weight member 46 and the outer weight member 50 to vibrate separately.

[0065] By providing the inner weight member 46 and the outer weight member 50, which can vibrate separately, along the shoulder bolt 42, the inner weight member 46 and the outer weight member 50 can move separately while being concentric. Therefore, when the inner weight member 46 and the outer weight member 50 are set to have different natural frequencies, the vibration damping device 40 is set to have two natural frequencies. As a result, one vibration damping device 40 can accommodate two resonant frequencies of the vehicle seat 10.

[0066] Furthermore, compared to the case where two vibration damping devices are installed to accommodate two resonance frequencies, the workability of installing the vibration damping device 40 can be improved. Furthermore, compared to the case where two vibration damping devices are installed, the cost of parts for the vibration damping device 40 can be reduced and the weight can be reduced.

[0067] The vibration damping device 40 of the first embodiment includes an annular inner weight member 46 having a first through hole 46A through which the stepped bolt 42 is inserted, an annular outer weight member 50 having a second through hole 50A through which the inner weight member 46 is inserted, inner coil springs 48 arranged on both sides of the inner weight member 46 in the axial direction D so as to surround the outer periphery of the stepped bolt 42, and outer coil springs 52 arranged on both sides of the outer weight member 50 in the axial direction D so as to surround the outer periphery of the inner coil spring 48.

[0068] By providing the inner weight member 46, through which the shoulder bolt 42 is inserted and in which the inner coil spring 48 is disposed on both sides in the axial direction D, and the outer weight member 50, through which the inner weight member 46 is inserted and in which the outer coil spring 52 is disposed on both sides in the axial direction D, the inner weight member 46 and the outer weight member 50 can operate separately. Therefore, when the inner weight member 46 and the outer weight member 50 are set to have different natural frequencies, the vibration damping device 40 is set to have two natural frequencies. As a result, one vibration damping device 40 can accommodate two resonant frequencies of the vehicle seat 10.

[0069] Moreover, the outer weight member 50 has a second through hole 50A through which the inner weight member 46 is inserted, which allows the outer weight member 50 to vibrate around the inner weight member 46 as an axis. This allows the inner weight member 46 and the outer weight member 50 to vibrate along the axial direction D of one shoulder bolt 42. As a result, the inner weight member 46 and the outer weight member 50 can share a common axis. This allows for reductions in component costs and weight of the vibration damping device 40.

[0070] Furthermore, by arranging the outer coil spring 52 so as to surround the outer periphery of the inner coil spring 48, the inner coil spring 48 is arranged inside the outer coil spring 52. This eliminates the space required for providing the outer coil spring 52. As a result, the vibration damping device 40 can be made smaller.

[0071] Furthermore, the inner coil spring 48 is used as a biasing member that biases the inner weight member 46, and the outer coil spring 52 is used as a biasing member that biases the outer weight member 50. Therefore, compared to when rubber members are used as biasing members, the stroke of the inner weight member 46 and the outer weight member 50 can be made longer. As a result, the kinetic energy of the inner weight member 46 and the outer weight member 50 can be increased. Therefore, the vibration damping device 40 has a simple configuration, is compact and lightweight, and can effectively absorb vibration energy.

[0072] Furthermore, the inner weight member 46 and the outer weight member 50 are movable along the axial direction D of the shank 42A of the shoulder bolt 42. Therefore, the inner weight member 46 and the outer weight member 50 have one degree of freedom. As a result, the natural frequency of the vibration damping device 40 can be easily set.

[0073] In the vibration damping device 40 of the first embodiment, the outer peripheral surface of the shoulder bolt 42 is covered with a collar member 44 made of resin, and the outer peripheral surface of the inner weight member 46 is covered with grease G.

[0074] By covering the outer peripheral surface of the stepped bolt 42 with the resin collar member 44, the resin collar member 44 is interposed between the stepped bolt 42 and the inner weight member 46. Therefore, abnormal noise generated between the stepped bolt 42 and the inner weight member 46 can be suppressed.

[0075] This also reduces frictional heat generated between the shoulder bolt 42 and the inner weight member 46. This reduces deformation of each component due to frictional heat generated between the shoulder bolt 42 and the inner weight member 46. As a result, the inner weight member 46 operates as desired, and can be vibrated at the desired resonance frequency.

[0076] Furthermore, by covering the outer peripheral surface of the inner weight member 46 with grease G, the grease G is interposed between the inner weight member 46 and the outer weight member 50. Therefore, abnormal noise generated between the inner weight member 46 and the outer weight member 50 can be suppressed.

[0077] Furthermore, frictional heat generated between the inner weight member 46 and the outer weight member 50 is also suppressed. Therefore, deformation of each component due to frictional heat generated between the inner weight member 46 and the outer weight member 50 is suppressed. As a result, the outer weight member 50 operates as desired, and the outer weight member 50 can be vibrated at the targeted resonance frequency.

[0078] In the vibration damping device 40 of the first embodiment, the inner coil spring 48 and the outer coil spring 52 are arranged in a compressed state.

[0079] By disposing the inner coil spring 48 and the outer coil spring 52 in a compressed state, when the inner weight member 46 and the outer weight member 50 move along the shoulder bolt 42, one of the inner coil spring 48 and the outer coil spring 52 is further compressed, while the other of the inner coil spring 48 and the outer coil spring 52 is extended but maintained in a compressed state. Therefore, when the inner weight member 46 and the outer weight member 50 vibrate, the inner coil spring 48 and the outer coil spring 52 are always in contact with the inner weight member 46 or the outer weight member 50. As a result, abnormal noise generated between the inner weight member 46 and the outer weight member 50 and the inner coil spring 48 and the outer coil spring 52 can be suppressed.

[0080] The vibration damping device 40 of the first embodiment is provided on the seat back 14 that supports the upper body of a seated occupant, or on the headrest 16 that supports the head of a seated occupant.

[0081] The vehicle seat 10 is attached to a vehicle body floor 26 via slide rails 20 and seat brackets so as to be slidable in the longitudinal direction of the vehicle. That is, since the lower end of the vehicle seat 10 is supported by the slide rails 20, the seat back 14 and the headrest 16 of the vehicle seat 10 are free ends and therefore vibrate more strongly than the seat cushion 12. For this reason, by providing a vibration damping device 40 to the seat back 14 or the headrest 16, which vibrate more strongly than the seat cushion 12, it is possible to effectively absorb the vibration energy of the vehicle seat 10 and improve the damping efficiency for attenuating the vibration of the vehicle seat 10.

[0082] In the vehicle seat 10 of the first embodiment, the natural frequencies of the inner weight member 46 and the outer weight member 50 are different from each other and are set to be the same as one of the two resonance frequencies of the vehicle seat 10.

[0083] By setting the natural frequencies of the inner weight member 46 and the outer weight member 50 to be the same as the resonance frequency of the vehicle seat 10, the inner weight member 46 and the outer weight member 50 resonate with the resonance of the vehicle seat 10. This converts the vibration energy of the vehicle seat 10 into vibration energy of the inner weight member 46 and the outer weight member 50. As a result, the vibration energy of the vehicle seat 10 is absorbed, and the vibration of the vehicle seat 10 is effectively damped.

[0084] Furthermore, the natural frequencies of the inner weight member 46 and the outer weight member 50 are set to be different from each other and the same as the two resonant frequencies of the vehicle seat 10, so that they can be adapted to the two resonant frequencies of the vehicle seat 10.

[0085] In the vehicle seat 10 of the first embodiment, the vibration damping device 40 is provided on the upper end side of the seat back frame 28 that constitutes the framework of the seat back 14.

[0086] Incidentally, the seat back 14 has a larger outer shape than the headrest 16, making it easier to ensure space for installing the vibration damping device 40. By providing the vibration damping device 40 on the upper end side of the seat back frame 28 that forms the framework of the seat back 14, it is possible to ensure sufficient space for installing the vibration damping device 40.

[0087] In the vehicle seat 10 of the first embodiment, the shoulder bolt 42 is installed along the seat width direction.

[0088] By arranging the shoulder bolt 42 along the seat width direction, vibrations of the vehicle seat 10 along the seat width direction can be damped.

[0089] Second Embodiment The vibration damping device of the second embodiment differs from the vibration damping device of the first embodiment in that the configuration of the weight member is different.

[0090] [Configuration of vibration damping device] The configuration of the vibration damping device of the second embodiment will be described below. Note that the same terms or symbols will be used to describe parts that are the same as or equivalent to those described in the first embodiment.

[0091] As shown in FIG. 9, the vibration damping device 140 includes a shoulder bolt 42 as an axial member, a collar member 44, an inner weight member 46 as a weight member, an inner coil spring 48 as a coil spring, a second inner weight member 146 as a weight member, and a base plate 54.

[0092] (Second inner weight member 146) The second inner weight member 146 is arranged closer to one end in the axial direction D than the inner weight member 46. The second inner weight member 146 is arranged radially outward from the collar member 44. The second inner weight member 46 is made of metal and formed into a cylindrical shape. The second inner weight member 146 has a third through hole 146A through which the shoulder bolt 42 and the collar member 44 are inserted. The inner diameter of the third through hole 146A is formed to be approximately the same size as the outer diameter of the collar member 44. The inner weight member 46 is configured to be movable in the axial direction D along the collar member 44.

[0093] (Inner coil spring 48) The inner coil spring 48 includes a first inner coil spring 48A, a second inner coil spring 48B, and a third inner coil spring 48C.

[0094] The first inner coil spring 48A is disposed on the other end side of the inner weight member 46. In a compressed state, the first inner coil spring 48A is disposed between an end face on the other end side of the inner weight member 46 and an end face on one end side of the head 42B.

[0095] The second inner coil spring 48B is disposed on one end side of the inner weight member 46. The second inner coil spring 48B is disposed in a compressed state between an end face on one end side of the inner weight member 46 and an end face on the other end side of the second inner weight member 146.

[0096] The third inner coil spring 48C is disposed on one end side of the second inner weight member 146. In a compressed state, the third inner coil spring 48C is disposed between an end face on one end side of the second inner weight member 146 and an end face on the other end side of the base plate 54 attached to the male thread portion 42C of the shoulder bolt 42.

[0097] Even with the vibration damping device 140 configured in this way, one vibration damping device can accommodate two resonance frequencies of the vehicle seat 10. Note that other configurations and effects are substantially the same as those of the above embodiment, and therefore description thereof will be omitted.

[0098] Third Embodiment The vibration damping device of the third embodiment differs from the vibration damping devices of the above embodiments in that the weight member has a different configuration.

[0099] [Configuration of vibration damping device] The configuration of the vibration damping device of the third embodiment will be described below. Note that the same terms or symbols will be used to describe parts that are the same as or equivalent to those described in the above embodiments.

[0100] As shown in FIG. 10 , the vibration damping device 240 includes a shoulder bolt 42 as an axial member, a collar member 44, an inner weight member 46 as a weight member, an inner coil spring 48 as a coil spring, an outer weight member 50 as a weight member, an outer coil spring 52 as a coil spring, an outermost weight member 250 as a weight member, an outermost coil spring 252 as a coil spring, and a base plate 54.

[0101] (Outermost weight member 250) The outermost weight member 250 is disposed radially outward of the outer weight member 50. The outermost weight member 250 is made of metal and formed into a cylindrical shape. The outermost weight member 250 has a fourth through hole 250A through which the outer weight member 50 is inserted. The inner diameter of the fourth through hole 250A is formed to be approximately the same as the outer diameter of the outer weight member 50. The length in the axial direction D of the outermost weight member 250 can be approximately the same as the length in the axial direction D of the outer weight member 50. Note that the length in the axial direction D of the outermost weight member 250 may be shorter or longer than the length in the axial direction D of the outer weight member 50.

[0102] Grease G serving as a lubricating layer is interposed between the outermost weight member 250 and the outer weight member 50. In other words, the outer peripheral surface of the outer weight member 50 is covered with grease G serving as a lubricating layer. The outermost weight member 250 is configured to be movable in the axial direction D along the outer weight member 50.

[0103] (Outermost coil spring 252) The outermost coil spring 252 is disposed radially outward of the outer coil spring 52. The outermost coil spring 252 is formed to a size that allows the outer coil spring 52 to be inserted inside. The outer diameter of the outermost coil spring 252 is formed to be larger than the inner diameter of the outermost weight member 250. The outermost coil spring 252 includes a first outermost coil spring 252A and a second outermost coil spring 252B.

[0104] The first outermost coil spring 252A is disposed on the other end side of the outermost weight member 250. In a compressed state, the first outermost coil spring 252A is disposed between the end face on the other end side of the outermost weight member 250 and the end face on one end side of the head 42B. The first outermost coil spring 252A is disposed so as to surround the outer periphery of the first outer coil spring 52A.

[0105] The second outermost coil spring 252B is disposed on one end side of the outermost weight member 250. In a compressed state, the second outermost coil spring 252B is disposed between an end face on one end side of the outermost weight member 250 and an end face on the other end side of the base plate 54 attached to the male thread portion 42C of the shoulder bolt 42. The second outermost coil spring 252B is disposed so as to surround the outer periphery of the second outer coil spring 52B.

[0106] The vibration damping device 240 configured as described above can accommodate, with one vibration damping device, the three resonance frequencies of the vehicle seat 10. Note that other configurations and effects are substantially the same as those of the above embodiment, and therefore description thereof will be omitted.

[0107] The vibration damping device and the vehicle seat equipped with this vibration damping device of the present invention have been described above based on the above-mentioned embodiments. However, the specific configuration is not limited to these embodiments, and design changes are permitted as long as they do not deviate from the gist of the invention according to the claims.

[0108] In the above embodiment, an example was shown in which the vibration damping device 40 was attached to the bracket 34 so that the axial direction D of the stepped bolt 42 was aligned with the seat width direction. However, as shown in Fig. 11, the vibration damping device 40 may also be attached to the first piece 34A of the bracket 34 so that the axial direction D of the stepped bolt 42 is aligned with the seat front-rear direction when the seat back 14 is in an upright position. In this case, vibrations in the seat front-rear direction of the vehicle seat 10 can be damped.

[0109] 12, the vibration damping device 40 may be attached to the bracket 134 so that the axial direction D of the shoulder bolt 42 is aligned along a direction that includes components in the seat width direction, the seat front-rear direction, and the seat up-down direction. In this case, the vehicle seat 10 can damp vibrations that include components in the seat width direction, the seat front-rear direction, and the seat up-down direction of the vehicle seat 10.

[0110] In the first embodiment, the weight member is provided in two layers, an inner weight member 46 and an outer weight member 50, and in the third embodiment, the weight member is provided in three layers, an inner weight member 46, an outer weight member 50, and an outermost weight member 250. However, the weight member may be provided in four or more layers.

[0111] In the above embodiment, an example was shown in which one vibration damping device 40 was provided in the vehicle seat 10. However, a plurality of vibration damping devices may also be provided in the vehicle seat 10.

[0112] In the above embodiment, an example has been shown in which grease G is interposed as a lubricating layer between the outer weight member 50 and the inner weight member 46. However, a lubricating layer may also be formed by applying a resin coating to the outer peripheral surface of the inner weight member 46.

[0113] In the above embodiment, an example has been shown in which the vibration damping device 40 is provided at approximately the center in the seat width direction, at the upper end of the upper frame 27. However, the vibration damping device 40 may be provided on the right or left side in the seat width direction, or may be provided on the headrest stay, the lower frame 25, or the cushion frame 18.

[0114] In the above embodiment, an example was shown in which the inner weight member 46 was formed in a cylindrical shape. However, the inner weight member may have multiple protrusions on its outer peripheral surface. In this case, the contact area between the inner weight member 46 and the outer weight member 50 is reduced, and the grease G as a lubricating layer can be omitted.

[0115] In the above embodiment, an example was shown in which the vibration damping device of the present invention is applied to a vehicle seat, but the vibration damping device of the present invention can also be applied to seats in trains, airplanes, ships, and other vehicles. [Explanation of symbols]

[0116] 10 Vehicle seats 10A Seat frame 14 Seat back 16 Headrest 28 Seat back frame 40 Vibration damping device 42 Shoulder bolt (an example of a shaft component) 44 Colored parts 46 Inner weight member (an example of a weight member) 46A First through hole (an example of a through hole) 48 Inner coil spring (an example of a coil spring) 50 Outer weight member (an example of a weight member) 50A Second through hole (an example of a through hole) 52 Outer coil spring (an example of a coil spring) D-axis direction Grease (an example of a lubricating layer)

Claims

1. a shaft member attached to the seat frame; a plurality of weight members each having a through hole through which the shaft member is inserted and movable along the axial direction of the shaft member; coil springs arranged on both sides of each of the weight members in the axial direction, allowing each of the weight members to vibrate separately; Equipped with The weight member is an annular inner weight member having a first through hole through which the shaft member is inserted; an annular outer weight member having a second through hole through which the inner weight member is inserted; Equipped with The coil spring is inner coil springs arranged on both sides of the inner weight member in the axial direction so as to surround an outer periphery of the shaft member; outer coil springs arranged on both sides of the outer weight member in the axial direction so as to surround an outer periphery of the inner coil spring; Equipped with The outer circumferential surface of the shaft member is covered with a resin collar member, The outer circumferential surface of the inner weight member is covered with a lubricating layer.

2. The coil spring is disposed in a compressed state.

2. The vibration damping device of claim 1.

3. The vibration damping device according to claim 1 or claim 2 is provided on a seat back that supports the upper body of a seated occupant, or on a headrest that supports the head of a seated occupant. Vehicle seat.

4. The natural frequencies of the weight members are different from one another and are set to be the same as any one of a plurality of resonance frequencies of the vehicle seat. The vehicle seat according to claim 3.

5. The vibration damping device is provided on the upper end side of a seat back frame that constitutes the framework of the seat back.

5. The vehicle seat according to claim 3 or 4.

6. The shaft member is installed along the seat width direction. The vehicle seat according to any one of claims 3 to 5.

7. The shaft member is installed along the front-rear direction of the seat. The vehicle seat according to any one of claims 3 to 6.

8. The shaft member is installed to include components in the seat width direction, the seat front-rear direction, and the seat up-down direction. The vehicle seat according to any one of claims 3 to 7.

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