Vibration reduction device and vehicle seat

Abstract

To reduce cost of manufacturing a weight.SOLUTION: A vibration reduction device 10 includes a shaft member 20, a plurality of weights 52, and a weight support member 25. The weights 52 are formed into a columnar shape extending along an axial direction of the shaft member 20 and arranged around the shaft member 20. The weight support member 25 includes: a cylindrical part 40 formed into a cylindrical shape; and a first weight support part 54 and a second weight support part 56 for supporting the weights 52, and moves in the axial direction of the shaft member 20 together with the weights 52 while the shaft member 20 is inserted into the cylindrical part 40.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vibration reduction device and a vehicle seat. [Background technology]

[0002] The following Patent Document 1 discloses a vibration damping device (vibration reduction device) including a first weight and a second weight. The vibration reduction device described in this document includes a base and a first weight and a second weight that can vibrate relative to the base. The first weight and the second weight are arranged in a multi-layered manner so as to overlap in the radial direction. The base and the first weight are connected by a connecting member, and the first weight and the second weight are connected by a connecting member. The first weight and the second weight are capable of vibrating in different directions. This makes it possible to suppress vibrations in multiple directions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-68295 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in a vibration reduction device that includes a plurality of weights and a vehicle seat equipped with the same, it is desirable to be able to reduce the manufacturing costs of the weights, but the configuration described in the above-mentioned patent document leaves room for improvement in this regard.

[0005] In consideration of the above, an object of the present invention is to provide a vibration reducing device and a vehicle seat that can reduce the manufacturing cost of the weight. [Means for solving the problem]

[0006] The vibration reduction device of the first embodiment comprises an axial member, a plurality of weights formed in a columnar shape extending along the axial direction of the axial member and arranged around the axial member, a cylindrical portion formed in a cylindrical shape, and a weight support portion supporting the plurality of weights, the weight support member moving in the axial direction of the axial member together with the plurality of weights when the axial member is inserted into the cylindrical portion.

[0007] According to the vibration reduction device of the first aspect, a weight support member that supports a plurality of weights moves in the axial direction of the shaft member together with the plurality of weights. This reduces vibration of the member to which the vibration reduction device is attached. Here, the plurality of weights are formed in a columnar shape. In this configuration, for example, the plurality of weights can be obtained by cutting a long member to a predetermined length. As a result, the manufacturing cost of the weights can be reduced.

[0008] The second aspect of the vibration reduction device is the vibration reduction device of the first aspect, wherein the weight support member is formed in a circular plate shape with the axial direction of the shaft member as the thickness direction and is provided with a pair of weight support portions arranged at intervals in the axial direction of the shaft member, one of the weight support portions is formed with a weight fitting portion into which one end of a plurality of the weights fits, and the other weight support portion is formed with a weight fitting portion into which the other end of the plurality of the weights fits.

[0009] According to the vibration reduction device of the second aspect, the weights can be supported by the weight support member by fitting one end of each of the weights into a weight fitting portion formed in one of the weight support parts and fitting the other end of each of the weights into a weight fitting portion formed in the other weight support part. Also, in this configuration, the volume of the weight support member can be reduced compared to a configuration in which the entire weights are disposed in the weight support member.

[0010] The third aspect of the vibration reduction device is the vibration reduction device of the second aspect, in which the pair of weight support portions are connected in the axial direction of the shaft member by the cylindrical portion, the cylindrical portion has a two-part structure in the axial direction of the shaft member, one of the cylindrical portions has a first fitting portion on the side of the other cylindrical portion, and the other cylindrical portion has a second fitting portion on the side of the one cylindrical portion, and the first fitting portion and the second fitting portion are fitted together to connect the one cylindrical portion to the other cylindrical portion.

[0011] According to the vibration reduction device of the third aspect, first, one end of the plurality of weights is fitted into a weight fitting portion formed on one of the weight support portions. Next, the first fitting portion and the second fitting portion are fitted together, and the other end of the plurality of weights is fitted into a weight fitting portion formed on the other weight support portion. In this way, in the vibration reduction device of the third aspect, the plurality of weights can be supported on the weight support member by the above procedure.

[0012] The fourth aspect of the vibration reduction device is the vibration reduction device of the third aspect, in which coil springs are provided on one axial side and the other axial side of the shaft member relative to the weight support member, and one of the weight support parts is formed with a coil spring abutment portion against which one of the coil springs abuts and an annular groove is provided around the coil spring abutment portion, and the other weight support part is formed with a coil spring abutment portion against which the other coil spring abuts and an annular groove is provided around the coil spring abutment portion.

[0013] According to the vibration reduction device of the fourth aspect, one coil spring abuts against the coil spring abutment portion of one weight support part, and the other coil spring abuts against the coil spring abutment portion of the other weight support part. Also, an annular groove is formed around the coil spring abutment portion of each weight support part. As a result, even if the coil spring shifts from the coil spring abutment portion, the coil spring is locked in the annular groove, so that further shifting of the coil spring can be suppressed.

[0014] The vehicle seat of the fifth aspect comprises a seat cushion that supports the buttocks of a seated occupant, a seat back that supports the back of the seated occupant, and a vibration reduction device of any one of the first to fourth aspects provided on at least one of the seat cushion and the seat back.

[0015] In the vibration reduction device constituting a part of the vehicle seat of the fifth aspect, a weight support member supporting a plurality of weights moves in the axial direction of the shaft member together with the plurality of weights. This reduces vibrations of the vehicle seat to which the vibration reduction device is attached. Here, the plurality of weights are formed in a columnar shape. In this configuration, for example, the plurality of weights can be obtained by cutting a long member to a predetermined length. As a result, the manufacturing cost of the weights can be reduced. Effect of the Invention

[0016] The vibration reduction device and vehicle seat according to the present invention have an excellent effect of reducing the manufacturing costs of the weight. [Brief description of the drawings]

[0017] [Figure 1] 1 is a side view showing a vehicle seat equipped with a vibration reduction device of the present embodiment. [Diagram 2] 1 is a perspective view showing a vibration reduction device according to an embodiment of the present invention; [Diagram 3] 1 is an exploded perspective view showing a vibration reduction device according to an embodiment of the present invention; [Figure 4] 1 is a cross-sectional view showing a cross section of a vibration reduction device of the present embodiment taken along the axial direction of a shaft member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] A vehicle seat 12 equipped with a vibration reduction device 10 of the present embodiment will be described with reference to Figs. 1 to 4.

[0019] 1 shows a side view of a vehicle seat 12 equipped with a vibration reduction device 10 of this embodiment, as viewed from the left side of the seat. In the figure, the arrow FR indicates the front side of the seat, the arrow UP indicates the upper side of the seat, the arrow RH indicates the right side in the width direction of the seat, and the arrow LH indicates the left side in the width direction of the seat. In the following description, when the directions of front-rear, up-down, and left-right are used unless otherwise specified, they refer to front-rear in the front-rear direction of the seat, up-down in the up-down direction of the seat, and left-right in the width direction of the seat.

[0020] As shown in Fig. 1, the vehicle seat 12 includes a seat cushion 14 that supports the buttocks of a seated occupant from below, a seat back 16 that supports the back of the seated occupant from the rear side of the seat, and a headrest 18 that supports the head of the seated occupant from the rear side of the seat. The seat back 16 is attached to the rear end of the seat cushion 14 and can be tilted in the front-rear direction. The headrest 18 is attached to the upper end of the seat back 16. The vibration reduction device 10 is provided inside an upper portion of the seat back 16 and is fixed to a seat back frame that forms the framework of the seat back 16. The vibration reduction device 10 may be provided in either the seat cushion 14 or the seat back 16, or may be provided in both the seat cushion 14 and the seat back 16.

[0021] 2 and 3, the vibration reduction device 10 includes an axis member 20 fixed to the seat back frame, a plurality of weights 52 arranged around the axis member 20, and a weight support member 25 that supports the plurality of weights 52. The vibration reduction device 10 also includes a pair of coil springs 26 provided on both sides of the weight support member 25.

[0022] As shown in FIG. 3, the shaft member 20 is a stepped bolt made of a metal material, and includes a bolt shank 28, a threaded portion 30, and a bolt head 32. The bolt shank 28 is formed in a cylindrical shape and constitutes an axial intermediate portion of the shaft member 20. The threaded portion 30 constitutes an end portion on one axial side of the shaft member 20. A male thread is formed on the outer periphery of the threaded portion 30. The outer diameter D2 of the threaded portion 30 is set to be smaller than the outer diameter D1 of the bolt shank 28. As a result, a step portion 34 is formed at the boundary between the threaded portion 30 and the bolt shank 28. The bolt head 32 constitutes an end portion on the other axial side of the shaft member 20. The outer diameter D3 of the bolt head 32 is set to be larger than the outer diameter D1 of the bolt shank 28. A tool engagement portion 36 is formed on the opposite side of the bolt shank 28 in the bolt head 32 to the bolt shank 28. A tool engagement portion 36 is formed to engage with a tool such as a hexagonal wrench. The arrow Z direction, the arrow R direction, and the arrow C direction appropriately shown in the drawings respectively indicate one axial side, the radially outer side, and one circumferential side of the shaft member 20. Furthermore, hereinafter, when the axial direction, radial direction, and circumferential direction are simply indicated, they refer to the axial direction, radial direction, and circumferential direction of the shaft member 20 unless otherwise specified.

[0023] The weights 52 are formed in a cylindrical shape extending along the axial direction. In this embodiment, eight weights 52 are provided. The weights 52 have the same outer diameter D10 and axial length L3. The weights 52 in this embodiment are manufactured by cutting a long member (a rod-shaped steel material, for example) having an outer diameter D10 into pieces of length L3. The weights 52 have end portions 52A on one side of the axial direction and end portions 52B on the other side of the axial direction supported by a weight support member 25, which will be described later. The number and shape of the weights 52 (the mass of the weights 52) may be appropriately set in consideration of the frequency at which vibration is to be reduced, etc.

[0024] The weight support member 25 is formed using a resin material. As shown in Figures 3 and 4, the weight support member 25 includes a cylindrical portion 40 formed in a cylindrical shape. The inner diameter D6 of the cylindrical portion 40 is set to be slightly larger than the outer diameter D1 of the bolt shank 28. This allows the bolt shank 28 to be inserted into the inside of the cylindrical portion 40 with a clearance.

[0025] The weight support member 25 also includes a first weight support portion 54 as a weight support portion that protrudes radially outward from an end portion on one axial side of the cylindrical portion 40. The weight support member 25 also includes a second weight support portion 56 as a weight support portion that protrudes radially outward from an end portion on the other axial side of the cylindrical portion 40. The first weight support member 54 and the second weight support portion 56 are formed in a disk shape with the axial direction as the thickness direction, and are arranged at an interval in the axial direction. The first weight support member 54 and the second weight support portion 56 are also configured to be connected in the axial direction by the cylindrical portion 40.

[0026] Further, a plurality of (eight in this embodiment) weight fitting portions 58 into which end portions 52A on one axial side of the plurality of weights 52 are respectively fitted are formed on the outer periphery of the first weight support portion 54. The plurality of weight fitting portions 58 are recesses that are open on the other axial side, and are arranged at equal intervals along the circumferential direction.

[0027] Further, a plurality of (eight in this embodiment) weight fitting portions 58 into which the end portions 52B on the other axial side of the plurality of weights 52 are respectively fitted are formed on the outer periphery of the second weight support portion 56. The plurality of weight fitting portions 58 are recesses that are open on one axial side, and are arranged at equal intervals along the circumferential direction.

[0028] 4, one axial side surface of the inner circumferential portion of the first weight support portion 54 serves as a coil spring abutment portion 60 against which one coil spring 26 abuts. An annular groove 62 is formed around the coil spring abutment portion 60 of the first weight support portion 54 so as to surround the coil spring abutment portion 60. This annular groove 62 is a concave recess that is open on one axial side.

[0029] As shown in FIG. 3 and FIG. 4, the surface on the other axial side of the inner circumferential portion of the second weight support portion 56 is a coil spring abutment portion 60 with which the other coil spring 26 abuts. An annular groove 62 is formed around the coil spring abutment portion 60 of the second weight support portion 56 so as to surround the coil spring abutment portion 60. The annular groove 62 is a concave recess with one axial side open. As shown in FIG. 3, when the annular groove 62 is viewed from the axial direction, the edge on the radial inner side of the annular groove 62 is formed in a circular shape. When the annular groove 62 is viewed from the axial direction, the edge on the radial outer side of the annular groove 62 is formed in a star shape. As a result, the groove width (diameter dimension) of the annular groove 62 is configured such that narrow portions and wide portions are alternately arranged along the circumferential direction. The annular groove 62 formed in the first weight support portion 54 is configured similarly to the annular groove 62 formed in the second weight support portion 56.

[0030] 3 and 4, in this embodiment, the cylindrical portion 40 has a two-part structure in the axial direction. More specifically, the cylindrical portion 40 is divided at the center in the axial direction. For convenience of explanation, the part on one axial side of the divided cylindrical portion 40 will be referred to as one cylindrical portion 40, and the part on the other axial side of the divided cylindrical portion 40 will be referred to as the other cylindrical portion 40.

[0031] The end portion on the other axial direction of one cylindrical portion 40 serves as a first fitting portion 64. The outer diameter D11 of one cylindrical portion 40 is substantially constant from the end portion on one axial direction side to the end portion on the other axial direction which is the first fitting portion 64. Also, a locking protrusion 68 that protrudes radially outward is formed on the outer periphery of the first fitting portion 64.

[0032] The end portion on one axial side of the other cylindrical portion 40 is the second fitting portion 66. The outer diameter D12 of the other cylindrical portion 40 is larger at the end portion on one axial side, which is the second fitting portion 66, than at the portion on the other axial side. The inner diameter D13 of the second fitting portion 66 is substantially the same as the outer diameter D11 of the first fitting portion 64. This allows the first fitting portion 64 to be inserted into the second fitting portion 66. A locking recess 70 is formed on the inner periphery of the second fitting portion 66. When the first fitting portion 64 is inserted into the second fitting portion 66, the locking protrusion 68 protruding from the first fitting portion 64 is disposed inside the locking recess 70. This maintains the fitted state between the first fitting portion 64 and the second fitting portion 66, and maintains the connection state between the one cylindrical portion 40 and the other cylindrical portion 40.

[0033] The pair of coil springs 26 are compression coil springs set to the same dimensions and spring constants, and the shaft member 20 is inserted into their inner periphery. The coil spring 26 arranged on one axial side of the weight support member 25 abuts against the coil spring abutment portion 60 of the first weight support portion 54. The coil spring 26 arranged on the other axial side of the weight support member 25 abuts against the coil spring abutment portion 60 of the second weight support portion 56.

[0034] The coil spring 26 arranged on one axial side of the weight support member 25 is axially compressed between a temporary washer 48 fixed to the shaft member 20 while in contact with the stepped portion 34 and the weight support member 25. The temporary washer 48 is a member used for distributing the vibration reduction device 10 as an assembly before it is attached to the vehicle seat 12. With the threaded portion 30 of the shaft member 20 inserted into the temporary washer 48, the nut 50 is screwed into the threaded portion 30, thereby fixing the temporary washer 48 to the shaft member 20. When the vibration reduction device 10 is attached to the vehicle seat 12, the temporary washer 48 is removed, and a part of the seat back frame is placed in the area corresponding to the temporary washer 48.

[0035] The coil spring 26 , which is disposed on the other axial side of the weight support member 25 , is compressed in the axial direction between the bolt head 32 and the weight support member 25 .

[0036] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0037] 2 to 4, in the vibration reduction device 10 of this embodiment, the bolt shaft portion 28 of the shaft member 20 is inserted into the cylindrical portion 40 of the weight support member 25. This allows the multiple weights 52 to be supported on the shaft member 20 via the weight support member 25, and allows the multiple weights 52 to be supported movably along the shaft member 20. Then, as shown in FIGS. 1 to 4, when the vehicle seat 12 equipped with the vibration reduction device 10 of this embodiment described above vibrates in the axial direction of the shaft member 20, the multiple weights 52 move along the shaft member 20 together with the weight support member 25. This suppresses resonance of the vehicle seat 12.

[0038] Here, the multiple weights 52 constituting a part of the vibration reduction device 10 are manufactured by cutting a long member (a steel rod, for example) having an outer diameter D10 into pieces of length L3. This makes it possible to reduce the manufacturing cost of the multiple weights 52. In addition, in this embodiment, the shaft member 20 and the multiple weights 52 are configured not to slide directly against each other. This makes it possible to eliminate the need to subject the shaft member 20 and the multiple weights 52 to surface treatment that takes into account contact between the shaft member 20 and the multiple weights 52. This also makes it possible to reduce the manufacturing cost of the multiple weights 52.

[0039] In this embodiment, the end portions 52A on one axial side of the multiple weights 52 are fitted into the weight fitting portions 58 formed in the first weight support portion 54 of the weight support member 25, and the end portions 52B on the other axial side of the multiple weights 52 are fitted into the weight fitting portions 58 formed in the second weight support portion 56 of the weight support member 25, thereby making it possible to support the multiple weights 52 on the weight support member 25. In addition, in this configuration, the volume of the weight support member 25 can be reduced compared to a configuration in which the entire multiple weights are disposed inside the weight support member 25.

[0040] In addition, in this embodiment, the cylindrical portion 40 of the weight support member 25 has a two-part structure in the axial direction. In the configuration of the weight support member 25 of this embodiment, first, the end portions 52B on the other axial side of the multiple weights 52 are fitted into the multiple weight fitting portions 58 formed in the second weight support portion 56. Next, the first fitting portion 64 and the second fitting portion 66 are fitted into each other, and the end portions 52A on one axial side of the multiple weights 52 are fitted into the multiple weight fitting portions 58 formed in the first weight support portion 54. In this way, in this embodiment, the multiple weights 52 can be supported by the weight support member 25 in the above procedure. In addition, in the above procedure, when the multiple weights 52 are supported by the weight support member 25, the multiple weights 52 can be prevented from coming apart.

[0041] Furthermore, in this embodiment, one coil spring 26 abuts against the coil spring abutment portion 60 of the first weight support portion 54, while the other coil spring 26 abuts against the coil spring abutment portion 60 of the second weight support portion 56. Also, an annular groove 62 is formed around the coil spring abutment portions 60 of the first weight support portion 54 and the second weight support portion 56. As a result, even if the coil spring 26 shifts from the coil spring abutment portion 60, the coil spring 26 is locked in the annular groove 62, thereby preventing the coil spring 26 from shifting any further.

[0042] In the present embodiment, an example has been described in which the annular groove 62 is formed around the coil spring abutment portion 60 of the first weight support portion 54 and the second weight support portion 56, but the present invention is not limited to this. For example, if another configuration for suppressing the shear movement of the coil spring 26 is applied, the annular groove 62 does not have to be formed.

[0043] In the present embodiment, the cylindrical portion 40 of the weight support member 25 has a two-part structure in the axial direction, but the present invention is not limited to this. Whether or not the cylindrical portion 40 of the weight support member 25 has a two-part structure in the axial direction can be appropriately selected in consideration of the procedure for assembling the multiple weights 52 to the weight support member 25.

[0044] Furthermore, in the present embodiment, an example has been described in which the central portions in the axial direction of the multiple weights 52 are exposed from the weight support member 25, but the present invention is not limited to this. For example, the multiple weights 52 may be entirely covered by the weight support member 25.

[0045] In addition, in the present embodiment, an example in which the weights 52 are formed in a cylindrical shape has been described, but the present invention is not limited to this. For example, the weights 52 may be formed in a prismatic shape.

[0046] Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it is of course possible to implement the present invention in various other modified forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0047] 10. Vibration reduction device 12 Vehicle seats 14 Seat cushion 16 Seat back 20 Shaft member 25 Weight support member 26 Coil spring 40 Cylindrical part 52 Weight 54 1st weight support part (weight support part) 56 2nd weight support part (weight support part) 58 Weight fitting part 60 Coil spring contact part 62 Circular groove 64 First fitting part 66 Second fitting part

Claims

1. A shaft member; A plurality of weights each formed in a columnar shape extending along the axial direction of the shaft member and arranged around the shaft member; a weight support member having a cylindrical portion formed in a cylindrical shape and a weight support portion supporting the plurality of weights, the weight support member moving together with the plurality of weights in an axial direction of the shaft member when the shaft member is inserted into the cylindrical portion; A vibration reduction device comprising:

2. the weight support member is formed in a disk shape with a thickness direction being in an axial direction of the shaft member, and includes a pair of the weight support portions arranged at an interval in the axial direction of the shaft member, One of the weight support parts is formed with a weight fitting part into which one end part of the plurality of weights is fitted, 2. The vibration reducing device according to claim 1, wherein the other of the weight support portions is formed with weight fitting portions into which the other ends of the plurality of weights are fitted.

3. The pair of weight support portions are connected in the axial direction of the shaft member by the cylindrical portion, The cylindrical portion has a two-part structure in the axial direction of the shaft member, A first fitting portion is provided on the one cylindrical portion side toward the other cylindrical portion, and a second fitting portion is provided on the other cylindrical portion side toward the one cylindrical portion, The vibration reduction device according to claim 2 , wherein one of the cylindrical portions and the other of the cylindrical portions are connected to each other by fitting the first fitting portion and the second fitting portion together.

4. A coil spring is provided on one axial side and the other axial side of the shaft member with respect to the weight support member, One of the weight support parts is formed with a coil spring abutment part with which the one of the coil springs abuts, and an annular groove is provided around the coil spring abutment part, 4. The vibration reducing device according to claim 3, wherein the other weight support portion is formed with a coil spring abutment portion with which the other coil spring abuts, and an annular groove provided around the coil spring abutment portion.

5. a seat cushion that supports the buttocks of a seated occupant; A seat back that supports the back of a seated occupant; The vibration reduction device according to any one of claims 1 to 4, which is provided on at least one of the seat cushion and the seat back; A vehicle seat comprising:

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