Dynamic damper and vehicle seat

Abstract

To provide a dynamic damper capable of preventing an unnecessary collision sound during a rotational motion of a seatback following a seat arrangement.SOLUTION: A dynamic damper 91 comprises: a bracket 1 having a metal plate-like base 11 and first and second opposite walls 12 and 14 bent to oppose each other from both ends of the base in a first direction; a weight 21; a weight cover 221 that covers the weight; and a damper body 2 having a first support body P1 that is a connection pillar for elastically connecting the weight cover and the first opposite wall; a second support body P2 that is a connection pillar for elastically connecting the weight cover and the second opposite wall, and a third support body P3 that is a connection pillar for elastically connecting the weight cover and the base. The weight is supported on the bracket by the first to third support bodies.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a vehicle seat provided with a dynamic damper. The dynamic damper described in Patent Document 1 is fixedly arranged on a frame inside a seat back, and includes a bracket having a top plate and a pair of side plates bent from both ends of the top plate and facing each other, and a mass fitting (weight) connected to the pair of side plates by a rubber elastic body and arranged to face the top plate.

[0003] When the seat back is in a normal upright position, the dynamic damper described in Patent Document 1 is fixedly arranged on the frame with the top plate of the bracket on the front side and the pair of side plates in a vertical posture inside the seat back.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Among vehicle seats mounted on automobiles, there are those that can be rotated forward horizontally to a table state by various seat arrangements. Such a forward tilting rotation of the seat back is often forcefully performed by the occupant, and when a predetermined horizontal posture is reached, the locking mechanism operates and the rotation suddenly stops. Therefore, in the dynamic damper described in Patent Document 1, the weight forcefully collides with the top plate of the bracket due to inertia, and an unnecessary collision sound is likely to occur. This also poses a risk that the weight will collide with the frame during the operation of tilting the seat back backward to a simple bed state, generating a similar unnecessary collision sound. Therefore, there is a need for a dynamic damper and a vehicle seat that do not generate unnecessary collision sounds during the rotation operation of the seat back associated with seat arrangement.

Means for Solving the Problems

[0006] To solve the above problems, the present invention has the following configuration. 1) A bracket having a metal plate-shaped base portion, and a first opposing wall portion and a second opposing wall portion bent from both ends of the base portion in a first direction so as to face each other, a weight, a weight covering portion covering the weight, a first support body which is a connecting column elastically connecting the weight covering portion and the first opposing wall portion, a second support body which is a connecting column elastically connecting the weight covering portion and the second opposing wall portion, and a third support body which is a connecting column elastically connecting the weight covering portion and the base portion, a damper body having, comprising, The weight is a dynamic damper supported by the bracket by the first support body, the second support body, and the third support body. 2) The dynamic damper according to 1), wherein any one of the first support body, the second support body, and the third support body is composed of a plurality of the connecting columns. 3) A vehicle seat comprising a seat cushion, a seat back frame, and a seat back having the dynamic damper according to 1) or 2) attached to the seat back frame, The dynamic damper is attached in a posture such that the first direction is the longitudinal direction of the seat back frame and the base portion faces the front side of the seat back frame.

Advantages of the Invention

[0007] According to one aspect of the present invention, an effect is obtained in that no unnecessary hitting sound is generated by the rotation operation of the seat back accompanying the seat arrangement.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 11

Modes for Carrying Out the Invention

[0009] The vehicle seat according to the embodiment of the present invention will be described with reference to FIG. 1 using the seat ST as an example. For convenience of explanation, each direction of up, down, left, right, front, and rear is defined as the direction indicated by the arrows in FIG. 1. FIG. 1 is a perspective view of the seat ST as seen from obliquely above and to the upper left.

[0010] The seat ST is a vehicle seat mounted on a vehicle such as an automobile, and has a seat cushion ST1 and a seat back ST2 as shown in FIG. 1. The seat cushion ST1 is slidably supported in the front-rear direction by a pair of rails 92, 92 laid on the floor 93 of the vehicle so as to extend in the front-rear direction and be spaced apart in parallel in the left-right direction.

[0011] The seat back ST2 is connected at the rear end of the seat cushion ST1 by a reclining structure that can be tilted backward and locked at an arbitrary angle. Further, as a seat arrangement, the seat back ST2 can be tilted forward as indicated by the arrow DR1 in FIG. 1 to form a table-like posture in which the rear surface is substantially horizontal.

[0012] Inside the seat back ST2, a frame-like seat back frame ST2a serving as a skeleton and a dynamic damper 91 fixed to the seat back frame ST2a are accommodated. The dynamic damper 91 is arranged at a substantially central position in the width direction and at a position slightly above the center in the up-down direction in the seat back ST2.

[0013] This dynamic damper 91 will be described with reference to FIGS. 2 and 3. FIG. 2 is a rear view of the dynamic damper 91 alone, and FIG. 3 is a left side view of the dynamic damper 91 attached to the seat back frame ST2a.

[0014] The dynamic damper 91 has a bracket 1 and a damper body 2. The bracket 1 is formed by press-molding a metal plate, and has a base portion 11, an upper opposing wall portion 12, an upper attachment portion 13, a lower opposing wall portion 14, and a lower attachment portion 15. The metal plate is, for example, SPCC (cold-rolled steel sheet). The bracket 1 is formed symmetrically with respect to the center line CL1 extending in the vertical direction.

[0015] The base portion 11 is a flat plate-like portion that is rectangular with the vertical direction, which is the first direction, being longer in a rear view. The upper opposing wall portion 12 is a flat plate-like portion bent 90° backward from the upper end of the base portion 11. The upper attachment portion 13 is a flat plate-like portion bent 90° upward from the rear end of the upper opposing wall portion 12. The lower opposing wall portion 14 is a flat plate-like portion bent 90° backward from the lower end of the base portion 11 and facing parallel to the upper opposing wall portion 12. The lower attachment portion 15 is a flat plate-like portion bent 90° downward from the rear end of the lower opposing wall portion 14. That is, the upper opposing wall portion 12 and the lower opposing wall portion 14 are the first opposing wall portion and the second opposing wall portion bent so as to face each other from both ends in the first direction of the base portion 11, respectively.

[0016] An upper protruding portion 131 protruding upward is formed at the central portion in the left-right direction of the upper attachment portion 13. A through hole 132 is formed on the center line CL1 in the upper protruding portion 131. A lower protruding portion 151 protruding downward is formed at the central portion in the left-right direction of the lower attachment portion 15. A through hole 152 is formed on the center line CL1 in the lower protruding portion 151.

[0017] The damper main body 2 has a rectangular parallelepiped-shaped weight 21 that is a metal mass, and a rubber coating portion 22 that covers the entire surface of the weight 21. The metal forming the weight 21 is, for example, SS400 of hot-rolled steel for general structure. The rubber forming the coating portion 22 is, for example, NR / SBR (a blend rubber of natural rubber and styrene-butadiene rubber).

[0018] The coating portion 22 has a weight coating portion 221 that covers the weight 21, and first connecting columns 222, second connecting columns 223, third connecting columns 225, fourth connecting columns 226, and fifth connecting columns 228. The weight coating portion 221 has an upper surface 2t, a lower surface 2d, a left side surface 2l, a right side surface 2r, a front surface 2f, and a rear surface 2k. The first connecting column 222 and the second connecting column 223 are cylindrical, and are respectively provided on the upper surface 2t of the weight covering portion 221 so as to be spaced apart left and right and extend upward. The upper end portions of the first connecting column 222 and the second connecting column 223 are connected to a thin plate-shaped upper pedestal 224, and the upper pedestal 224 is fixed to the upper opposing wall portion 12 of the bracket 1. The third connecting column 225 and the fourth connecting column 226 are cylindrical, and are respectively formed on the lower surface 2d of the weight covering portion 221 so as to be spaced apart left and right and extend downward. The lower end portions of the third connecting column 225 and the fourth connecting column 226 are connected to a thin plate-shaped lower pedestal 227, and the lower pedestal 227 is fixed to the lower opposing wall portion 14 of the bracket 1.

[0019] The fifth connecting column 228 is formed in a cylindrical shape extending forward from the front surface 2f of the weight covering portion 221 at the same position as the center of gravity G of the weight 21 in a rear view. The front end of the fifth connecting column 228 is connected to a thin plate-shaped front pedestal 229, and the front pedestal 229 is fixed to the base portion 11 of the bracket 1.

[0020] As shown in FIGS. 2 and 3, when the first connecting column 222, the second connecting column 223, the third connecting column 225, the fourth connecting column 226, and the fifth connecting column 228 are respectively the first support portion PL1 to the fifth support portion PL5, the weight 21 and the weight covering portion 221 are elastically supported by the first support portion PL1 to the fifth support portion PL5 with respect to the bracket 1. The first support portion PL1 and the second support portion PL2 that connect the weight covering portion 221 and the upper opposing wall portion 12 constitute the first support body P1. The third support portion PL3 and the fourth support portion PL5 that connect the weight covering portion 221 and the lower opposing wall portion 14 constitute the second support body P2. The fifth support portion PL5 that connects the weight covering portion 221 and the base portion 11 constitutes the third support body P3.

[0021] The upper protrusion 131 and the lower protrusion 151 of the bracket 1 are fixed to the attachment frame ST2b and the attachment frame ST2c of the seat back frame ST2a of the seat back ST2 by fixing tools N1 and N2 such as bolts and nuts, respectively. Thereby, the dynamic damper 91 is housed and arranged in the seat back ST2. Specifically, the dynamic damper 91 is arranged in a posture where the vertical direction is the longitudinal direction of the seat back ST2 and the base portion 11 is on the front side (the backrest side).

[0022] In the dynamic damper 91 attached to the seat back frame ST2a, in the seat arrangement of the seat ST, inertial forces corresponding to the forward and backward rotation of the seat back ST2 and inertial forces generated according to the behavior of the vehicle act. The mass of the weight 21 of the dynamic damper 91, and the shapes and elastic coefficients of the first support portion PL1 to the fifth support portion PL5 are set so that the movement caused by the inertial force is suppressed by a preset response acceleration.

[0023] When an inertial force in the vertical direction acts on the weight 21, one of the first support portion PL1 and the second support portion PL2 and the third support portion PL3 and the fourth support portion PL4 is compressed in the axial direction and the other is stretched in the axial direction. Further, the fifth support portion PL5 is sheared and deformed in a direction orthogonal to the axis. Thereby, the upward movement of the weight 21 is appropriately suppressed with preset response characteristics.

[0024] When an inertial force in the left - right direction acts on the weight 21, the first support portion PL1 to the fifth support portion PL5 are sheared and deformed in a direction orthogonal to each axis. Thereby, the left - right movement of the weight 21 is appropriately suppressed with preset response characteristics by the elastic repulsive forces of the first support portion PL1 to the fifth support portion PL5.

[0025] When an inertial force in the forward or backward direction acts on the weight 21, the first support portion PL1 to the fourth support portion PL4 are shearingly deformed in a direction orthogonal to each axis, and the fifth support portion PL5 is compressed or extended in the axial direction, respectively. Therefore, the forward and backward movement of the weight 21 is appropriately suppressed with preset response characteristics.

[0026] As described above, in the dynamic damper 91, the damper main body 2 and the base portion 11 of the bracket 1 are connected by the fifth support portion PL5 extending in the front-rear direction. Therefore, even when the seat back ST2 is rotated forward in the seat arrangement, the weight 21 and the weight covering portion 221 do not collide with the base portion 11 of the bracket 1. Further, even when the seat back ST2 is rotated backward, the weight 21 and the weight covering portion 221 do not collide with the seat back frame ST2a of the seat back ST2 or the like. Thereby, the dynamic damper 91 does not generate unnecessary collision noise during the rotation operation of the seat back ST2 associated with the seat arrangement.

[0027] Next, the relationship between the frequency and the resonance magnification of the dynamic damper 91 will be described with reference to FIGS. 4 and 5. FIG. 4 is a graph showing the relationship between the frequency of the dynamic damper 91 of the dynamic damper 91 and the resonance magnification in the left-right direction. FIG. 5 is a graph showing the relationship between the frequency of the dynamic damper 91 and the resonance magnification in the vertical direction. In each graph, the characteristics of the conventional dynamic damper without the fifth connecting column 228 are shown by a broken line.

[0028] As shown in FIG. 4, in the left-right direction, in the dynamic damper 91, a peak suppressed to about 7 times, which is smaller than the resonance magnification (about 9 times) near 18 Hz of the conventional dynamic damper, appears near 19 Hz. Further, in the dynamic damper 91, a resonance with a resonance magnification of slightly more than 2 times appears at 29 to 30 Hz, which is not recognized in the conventional dynamic damper. As shown in FIG. 5, in the longitudinal up-and-down direction, in the dynamic damper 91, instead of the small peak observed at around 19 Hz in the conventional dynamic damper, peaks with a resonance magnification of about 8 times appear at two locations around 19 Hz and around 28 Hz.

[0029] Thus, even if it has the fifth connecting column which is the fifth support part PL5, it can be said that it has the same characteristics as the case where there is no fifth support part PL5 in terms of the generation of a peak around 19 Hz and has the function as the dynamic damper 91. The dynamic damper 91 can suppress the resonance of the seat ST by adjusting and optimizing the resonance magnification by adjusting the shapes of the first support part PL1 to the fifth support part PL5 and the mass of the weight 21 and the like.

[0030] The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention.

[0031] (Modification Example 1) A dynamic damper 91A which is a modification example 1 of the dynamic damper 91 will be described with reference to FIGS. 6 and 7. FIG. 6 is a rear view of the dynamic damper 91A of modification example 1, and FIG. 7 is a left side view of the dynamic damper 91A.

[0032] The dynamic damper 91A has a damper main body 2A instead of the damper main body 2 of the dynamic damper 91. The damper main body 2A has a covering part 22A that covers the entire surface of the weight 21. The covering part 22A has a weight covering part 221A having a first protruding part 231, a second protruding part 232, a third protruding part 233, and a fourth protruding part 234 instead of the weight covering part 221. The weight covering part 221A has an upper surface 2At, a lower surface 2Ad, a left side surface 2Al, a right side surface 2Ar, a front surface 2Af, and a rear surface 2Ak.

[0033] The first protruding part 231 is formed at the upper part of the rear surface 2Ak of the weight covering part 221A. The first protruding part 231 has a substantially triangular mountain-shaped constant cross-sectional shape and is a protruding part extending in the left-right direction. The third protrusion 233 is formed on the front surface 2Af of the weight covering portion 221A so as to protrude forward with the same shape and at the same vertical position as the first protrusion 231. The second protrusion 232 and the fourth protrusion 234 are formed in the same shape and symmetrically with respect to the first protrusion 231 and the third protrusion 233 in the vertical direction on the weight covering portion 221A.

[0034] The dynamic damper 91A has a damper body 2A on which the first to fourth protrusions 231 to 234 are formed. Thus, for example, when an excessive rotational force acts around the center of gravity G as indicated by the arrow DR2 as shown in FIG. 7, one of the thick third protrusion 233 and the fourth protrusion 234 that is not a thin-walled part collides with the base portion 11 of the bracket 1. Since the third protrusion 233 and the fourth protrusion 234 are parts where rubber is thickly formed, even if the damper body 2A collides with the bracket 1 due to an unexpected excessive rotational force, the generated sound volume is suppressed.

[0035] (Modification 2) A dynamic damper 91B, which is a modification 2 of the dynamic damper 91, will be described with reference to FIGS. 8 and 9. FIG. 8 is a rear view of the dynamic damper 91B of modification 2, and FIG. 9 is a left side view of the dynamic damper 91B.

[0036] The dynamic damper 91B has a damper body 2B instead of the damper body 2 of the dynamic damper 91. The damper body 2B uses a weight 21B whose rear view shape is a rectangle connected to the lower part of a trapezoid with a narrow upper width instead of the weight 21 of the damper body 2. The damper body 2B has a rubber covering portion 22B that covers the entire surface of the weight 21B. The covering portion 22B has a weight covering portion 221B that covers the weight 21B, and first to fifth connecting columns 222, 223, 225, 226, and 228.

[0037] The weight covering portion 221B has an upper surface 2Bt, a lower surface 2Bd, a front surface 2Bf, and a rear surface 2Bk. Further, the weight covering portion 221B has, as left and right side surfaces, a left inclined side surface 2Blg and a right inclined side surface 2Brg that approach the center line CL1 as they go upward, and a left side surface 2Bl and a right side surface 2Br that are respectively connected to the lower sides of the left inclined side surface 2Blg and the right inclined side surface 2Brg and are parallel to the center line CL1. Due to this shape, the position of the center of gravity GB of the damper body 2B is below the position of the center of gravity G of the damper body 2. The fifth connecting column 228, which is the fifth support portion PL5, is provided at a position corresponding to the center of gravity GB below the damper body 2 on the front surface 2Bf of the damper body 2B.

[0038] Although the shape of the weight 21B of the dynamic damper 91B is different from that of the weight 21 of the dynamic damper 91, like the dynamic damper 91, no unnecessary hitting sound is generated by the rotation operation of the seat back ST2 associated with the seat arrangement.

[0039] (Modification 3) A dynamic damper 91C, which is a modification 3 of the dynamic damper 91, will be described with reference to FIGS. 10 and 11. FIG. 9 is a rear view of the dynamic damper 91C of modification 3, and FIG. 10 is a left side view of the dynamic damper 91C.

[0040] The dynamic damper 91C has a damper body 2C instead of the damper body 2B of the dynamic damper 91B. The damper body 2C has a covering portion 22C that covers the entire surface of the weight 21B. The covering portion 22C has a weight covering portion 221C that covers the entire surface of the weight 21B. The weight covering portion 221C has an upper surface 2Ct, a lower surface 2Cd, a front surface 2Cf, and a rear surface 2Ck. Further, the weight covering portion 221C has, as left and right side surfaces, a left inclined side surface 2Clg and a right inclined side surface 2Crg that approach the center line CL1 as they go upward, and a left side surface 2Cl and a right side surface 2Cr that are respectively connected to the lower sides of the left inclined side surface 2Clg and the right inclined side surface 2Crg and are parallel to the center line CL1.

[0041] The dynamic damper 91C is different from the dynamic damper 91B of Modification 2 in that the fifth support portion PL5 is a fifth connecting column group 251G which is a group of a plurality (three in this example) of connecting columns 251 to 253 instead of a single fifth connecting column 228. Specifically, the fifth connecting column group 251G which is the fifth support portion PL5 includes a connecting column 251 provided above at the same position as the center of gravity GC in the left - right direction, and connecting columns 252 and 253 provided below on the right side and the left side of the center of gravity GC respectively in the left - right direction. Flat - plate - shaped pedestals 251a to 253a are provided at the tips of the connecting columns 251 to 253. The pedestals 251a to 253a are fixed to the base portion 11.

[0042] Similar to the dynamic damper 91B of Modification 2, the dynamic damper 91C also does not generate unnecessary knocking sounds during the pivoting operation of the seat back ST2 associated with the seat arrangement.

[0043] The first support P1 is not limited to being composed of the first connecting column 222 and the second connecting column 223 which are two connecting columns. It may be composed of only one of them, or three or more connecting columns. The second support P2 is not limited to being composed of the third connecting column 225 and the fourth connecting column 226 which are two connecting columns. It may be composed of only one of them, or three or more connecting columns.

[0044] The vehicle is not limited to an automobile. The shapes of the first to fifth support portions PL1 to PL5 only need to be columnar and are not limited to cylindrical. Also, the upper pedestal 224, the lower pedestal 227, the front pedestal 229, and the pedestals 251a to 253a may not be provided.

Explanation of Reference Numerals

[0045] 1 Bracket 11 Base Portion 12 Upper Opposing Wall Portion 13 Upper Mounting Portion 131 Upper Protrusion 132 Through - Hole 14 Lower Opposing Wall Portion 15 Lower Mounting Portion 151 Lower protrusion 152 Through hole 2, 2A, 2B, 2C Damper body 2f, 2Af, 2Bf, 2Cf Front surface 2k, 2Ak, 2Bk, 2Ck Rear surface 2t, 2At, 2Bt, 2Ct Upper surface 2d, 2Ad, 2Bd, 2Cd Lower surface 2l, 2Al, 2Bl, 2Cl Left side surface 2Blg, 2Clg Left inclined side surface 2r, 2Ar, 2Br, 2Cr Right side surface 2Brg, 2Crg Right inclined side surface 21, 21B Hammer 22, 22A, 22B, 22C Cover part 221, 221A, 221B, 221C Hammer cover part 222 First connecting column 223 Second connecting column 224 Upper pedestal 225 Third connecting column 226 Fourth connecting column 227 Lower pedestal 228 Fifth connecting column 229 Front pedestal 231 First protrusion 232 Second protrusion 233 Third protrusion 234 Fourth protrusion 251G Fifth connecting column group 251, 252, 253 Connecting column 251a, 252a, 253a Pedestal 91, 91A, 91B, 91C Dynamic damper 92 Rail 93 Floor CL1 Center line N1, N2 Fixture G, GB Center of gravity P1~P3 First~Third support PL1~PL5 First~Fifth support part ST Seat (vehicle seat) ST1 Seat cushion ST2 Seatback ST2a Seatback Frame ST2b, ST2c Mounting Frame

Claims

1. A bracket having a plate-shaped base portion made of metal, and a first opposing wall portion and a second opposing wall portion bent from both ends of the base portion in a first direction so as to oppose each other, a weight, a weight covering portion covering the weight, a first support body which is a connecting column elastically connecting the weight covering portion and the first opposing wall portion, a second support body which is a connecting column elastically connecting the weight covering portion and the second opposing wall portion, and a third support body which is a connecting column elastically connecting the weight covering portion and the base portion, and comprising a dynamic damper in which the weight is supported by the bracket by the first support body, the second support body, and the third support body.

2. The dynamic damper according to claim 1, wherein any one of the first support body, the second support body, and the third support body is composed of a plurality of the connecting columns.

3. A seat cushion, and a seat back having the dynamic damper according to claim 1 or claim 2 attached to a seat back frame, wherein the dynamic damper is attached to a vehicle seat in a posture in which the first direction is the longitudinal direction of the seat back frame and the base portion faces the front side of the seat back frame.

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