JP6134549B2 - Vehicle seat - Google Patents

Description

  The present invention relates to a vehicle seat having a headrest attached to a seat back.

  Conventionally, in a vehicle such as an automobile, floor vibration is transmitted to a seat on which an occupant is seated during traveling, resulting in unpleasant vibration. In particular, in a seat having a seat back that supports the back of the occupant, resonance occurs in the vicinity of a predetermined frequency (for example, near 20 Hz), which may cause discomfort to the occupant.

  As a countermeasure against such vibrations of the seat, Patent Document 1 discloses that the headrest pivots to the left and right with respect to the seatback by connecting the headrest frame to the seatback frame in a state in which the headrest frame can be bent via the joint portion. It is possible (pendulum motion possible), and by biasing the headrest to the middle position of the rotation range with respect to the seat back, the headrest functions as a dynamic damper when vibration is applied to the seat in the left-right direction, reducing vibration Technology has been proposed.

International Publication WO2010 / 150373

  In the technology using the headrest as disclosed in Patent Document 1 as a dynamic damper, the damping effect of vibration can be increased as the mass of the headrest is increased with respect to the mass of the seat back. There is a limit to the increase, and it is difficult to obtain a sufficient vibration damping effect.

  Further, in the technique of Patent Document 1, since the headrest is used as a dynamic damper, the attachment portion of the headrest to the seat back is elastically supported and effective against vibration in the left-right direction. There is a possibility that it may be difficult to fully perform the original function of the headrest, which absorbs force and protects the head of the occupant from whiplash.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle seat that can effectively reduce seat vibration and improve impact absorption in the front-rear direction by a headrest attached to a seat back. It is said.

A vehicle seat according to the present invention is a vehicle seat having a headrest attached to a seatback, and a pair of left and right legs that are rotatably supported by the seatback on a leg portion extending from the headrest. A frame member and a connecting body that connects the upper end sides of the pair of left and right frame members so as to have elasticity in the front-rear and left-right directions .

  According to the present invention, it is possible to effectively reduce the seat vibration by the headrest attached to the seat back and to improve the impact absorbing power in the front-rear direction.

A perspective view showing a vehicle seat Explanatory drawing showing the internal structure of a part of the seat back and the headrest Explanatory drawing showing the action of the dynamic damper Explanatory drawing which shows the deformation | transformation of the front-back direction of a headrest by planar view Explanatory drawing which shows the deformation | transformation of the front-back direction of a headrest by a side view Characteristic chart showing actual measurement results of vibration level of seat Characteristic chart showing actual measurement results of vibration level at the top of the headrest

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a seat that is installed in a vehicle such as an automobile and supports the body of the occupant when seated. The seat 1 includes a seat body 2 and a headrest 3 that is attached to an upper portion of the seat body 2 and protects the head of the occupant.

  The seat body 2 includes a seat cushion 4 that supports the butt of the occupant and a seat back 5 that supports the back of the occupant. The seat cushion 4 is connected to a floor of a vehicle body (not shown), and the seat back 5 is connected to the seat cushion 4 via a reclining mechanism (not shown).

  1, the X-axis direction indicates the left-right direction of the seat back 5 constituting the seat body 2, the Y-axis direction indicates the front-rear direction of the seat back 5, and the Z-axis direction indicates the up-down direction of the seat back 5. . In the following description, the front / rear / left / right / up / down directions indicate the directions with respect to the seat back 5.

  As shown in FIG. 2, the headrest 3 is connected to an upper cross member 6 a that forms a portion in the X-axis direction (left-right direction) above the seatback frame 6 that is a skeleton member of the seatback 5 via a pair of left and right sockets 7. Attached. The socket 7 is a cylindrical member disposed along the Z-axis direction (vertical direction), and a headrest frame 10 extending from the headrest 3 is supported by the socket 7.

  The headrest frame 10 includes a pair of frame members 11 arranged in the Z-axis direction (vertical direction) in the headrest 3 and divided into left and right, and is cushioned by a cushioning material such as a urethane layer 3 a filled in the headrest 3. Covered. Each frame member 11 includes a leg portion 11a extending to the outside of the headrest 10 and an upper upper end portion 11b bent in the X-axis direction (left-right direction) so as to face each other.

  The left and right frame members 11 are supported by the leg portions 11 a being rotatably inserted into the socket 7, and the upper end portions 11 b being elastically connected via the connecting body 12. The connecting body 12 connects the upper end portions 11b of the left and right frame members 11 so as to have elasticity in the Y-axis and X-axis directions (front-rear and left-right directions). In the present embodiment, the connecting body 12 includes an elastic member 13 that connects the upper end portions 11b of the left and right frame members 11 at the center, and a pipe-shaped metal material or resin material that stores and holds the elastic member 13. And the case 14 formed by the above.

  In FIG. 2, a coil spring is illustrated as the elastic member 13, but a leaf spring may be used, and elastic rubber or the like may be used instead of the spring. Although the case 14 can be omitted, when the case 14 is used, a viscous fluid such as oil or a compressive fluid such as an inert gas may be enclosed in the case 14.

  Such a connecting body 12 that elastically connects the left and right frame members 11 can function as a dynamic damper that reduces the vibration of the seat back 5 in each of the XY axial directions without requiring a large mass. Moreover, not only the vibration reduction by the dynamic damper, but also the shock absorption stroke for the impact force in the Y-axis direction due to the vehicle collision or the like can be increased, and the head protecting function of the headrest 3 original occupant can be improved. Further, the cushioning material layer such as the urethane layer 3a of the headrest 3 can be thinned, and the size and weight can be reduced.

  As shown in FIG. 3A, when the equivalent mass of the headrest 3 is M1 and the equivalent mass of the seat back 5 is M2, the vibration of the system in which the frames of the headrest 3 and the seat back 5 are used as springs is effectively suppressed. In order to reduce the vibration, the resonance point of the headrest 3 may be made substantially coincident with the resonance point of the seat back 5 to cancel the vibration in the opposite phase. In this case, generally, the headrest has a high resonance frequency because the mass is small compared to the seat back and the rigidity is high due to the relatively short frame length. Therefore, it is necessary to lower the resonance frequency of the headrest 3 so as to coincide with the resonance frequency of the seat back 5.

  In the present embodiment, the left and right frame members 11 of the headrest 3 are elastically coupled by the coupling body 12, thereby reducing the rigidity in each axial direction of the entire headrest 3 including the headrest frame 10 and lowering the resonance frequency. I am doing so. As a result, the resonance point in the headrest vibration Gm1 due to the mass M1 indicated by the alternate long and short dash line can substantially coincide with the resonance point P in the seatback vibration Gm2 indicated by the solid line M2 in FIG. Thus, the vibration level of the vibration Gm1m2 due to the masses M1 and M2 can be greatly reduced.

  As shown in FIGS. 4A and 5A, when an impact force F acts in the Y-axis direction (front-rear direction) due to a vehicle collision or the like, FIGS. As shown in FIG. 4, the joint portion between the upper end portion 11 b of the frame member 11 and the coupling body 12 strokes backward with the deformation of the urethane layer 3 a of the headrest 3, so that the impact force can be effectively absorbed. . Further, as shown in FIG. 5C, by deforming the leg portion 11a of the frame member 11 in the vicinity of the upper portion of the socket 7, as shown in FIG. 5C and FIG. The absorption stroke can be increased and the amount of shock energy absorption can be increased.

  FIG. 6 illustrates an actual measurement result of the vibration level when the seat back resonance frequency and the headrest resonance frequency are substantially matched. From FIG. 6, the vibration level Ghd when the resonance frequency indicated by the solid line in the figure is matched is significantly lower than the vibration level Gbase of the base before the resonance frequency indicated by the broken line in the figure is matched. You can see that

  In this case, as shown in FIG. 7, the vibration level Ghdtp at the upper end of the headrest 3 is also effectively reduced with respect to the vibration level Gbase of the base. Therefore, it is not necessary to take measures such as lowering the rigidity and lowering the resonance frequency by raising the position of the headrest and increasing the frame length, and the protection performance of the head is not deteriorated for a short person. .

  As described above, in the present embodiment, the upper end sides of the pair of left and right frame members 11 for attaching the headrest 3 to the seat back 5 are connected via the connecting body 12 so as to have elasticity in the front, rear, left and right directions. Yes. As a result, not only the resonance frequency of the headrest 3 as a whole can be lowered to lower the resonance frequency, and the resonance frequency of the headrest 3 can be made substantially coincident with the resonance frequency of the seat back 5 to reduce uncomfortable seat vibration. The occupant protection performance can be improved by increasing the absorption stroke with respect to the impact force in the front-rear direction.

DESCRIPTION OF SYMBOLS 1 Seat 2 Seat main body 3 Headrest 5 Seat back 6 Seat back frame 6a Upper cross member 7 Socket 10 Headrest frame 11 Frame member 12 Connection body 13 Spring 14 Case

Claims (3)

A vehicle seat having a headrest attached to a seat back,
In the headrest,
A pair of left and right frame members rotatably supported on the seat back by leg portions extending from the headrest;
A vehicle seat comprising: a connecting body that connects upper end sides of the pair of left and right frame members so as to have elasticity in the front and rear, left and right directions . The coupling body, the elastic member for connecting the upper end side of the pair of left and right frame members, the vehicle seat according to claim 1, characterized in that it is constituted by a case for housing and holding said elastic member . The vehicle seat according to claim 2 , wherein the elastic member is a spring.

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