Vehicle seat structure

Abstract

To provide a vehicle seat structure in which a seat cushion can be rocked in a seat width direction by leaf springs and the function of the leaf springs can be maintained satisfactorily even when support shafts are rotated.SOLUTION: A vehicle seat structure includes: a seat cushion that supports buttocks and thighs of an occupant from below; a center member 40 that is provided below the seat cushion and at a center in a seat width direction and extends in a seat front-rear direction; leaf springs 64, 68 connecting a front portion and a rear portion of the center member 40 and the seat cushion; a front support shaft 36 that is provided at a front portion of the seat cushion and extends in the seat width direction; and a rear support shaft 34 that is provided at a rear portion of the seat cushion and extends in the seat width direction. Therein: the front portion of the center member 40 is attached to be rotatable about an axis of the front support shaft 36 and immovable in the seat width direction; and the rear portion of the center member 40 is attached to be rotatable about an axis of the rear support shaft 34 and immovable in the seat width direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat structure. [Background technology]

[0002] Patent Document 1 discloses an in-vehicle seat device equipped with a support mechanism that supports a cushion pan of a seat cushion. In this in-vehicle seat device, the support mechanism includes a support shaft and a leaf spring, and is configured so that the pivot center position of the cushion pan can be changed by changing the inclination angle of the leaf spring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-24473 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the structure described in Patent Document 1, the front leaf spring and the rear leaf spring are independent, so in a structure equipped with a lift-up mechanism that moves the seat cushion up and down by rotating the support shaft, the function of the leaf spring may not be maintained well.

[0005] The present invention aims to provide a vehicle seat structure in which the seat cushion can be swung in the seat width direction by a leaf spring, and the function of the leaf spring can be maintained well even when the support shaft rotates. [Means for solving the problem]

[0006] The vehicle seat structure of claim 1 includes a seat cushion that supports the buttocks and thighs of an occupant from below, a center member that is located below the seat cushion and in the center of the seat width direction and extends in the front-to-rear direction of the seat, leaf springs that connect the front and rear portions of the center member to the seat cushion, a front support shaft that is located in the front portion of the seat cushion and forms a skeleton of the seat cushion and extends in the seat width direction, and a rear support shaft that is located in the rear portion of the seat cushion and forms a skeleton of the seat cushion and extends in the seat width direction, wherein the front portion of the center member is attached so as to be rotatable around the axis of the front support shaft but not move in the seat width direction, and the rear portion of the center member is attached so as to be rotatable around the axis of the rear support shaft but not move in the seat width direction.

[0007] In the vehicle seat structure according to claim 1, a center member is provided below the seat cushion and in the center in the seat width direction, and the front and rear portions of the center member are connected to the seat cushion by leaf springs, respectively. As a result, when a load is input to the seat cushion, the leaf springs elastically deform, thereby maintaining a good posture of the seated occupant.

[0008] A front support shaft is provided at the front of the seat cushion, and a rear support shaft is provided at the rear of the seat cushion, with the front support shaft and the rear support shaft extending in the seat width direction. The front portion of the center member is attached so as to be rotatable around the axis of the front support shaft but immovable in the seat width direction, and the rear portion of the center member is attached so as to be rotatable around the axis of the rear support shaft but immovable in the seat width direction. This prevents the leaf spring angles from changing even when the seat cushion is moved up or down by rotating the support shafts. Furthermore, because the front and rear leaf springs are connected via the center member, independent elastic deformation of the front and rear leaf springs is suppressed. Note that the term "immovable" does not refer only to a state in which movement is completely restricted, but also broadly encompasses a configuration in which the center member can move slightly within a range that does not cause twisting.

[0009] A vehicle seat structure according to a second aspect of the present invention is the vehicle seat structure according to the first aspect, wherein the leaf springs are configured to be elastically deformable in the seat width direction and are provided at four corners of the seat cushion.

[0010] In the vehicle seat structure according to claim 2, the leaf springs are provided at the four corners of the seat cushion, so that the seat cushion can more easily follow the movement of the seat cushion.

[0011] The vehicle seat structure according to claim 3 is the same as claim 1, wherein the front portion of the center member is attached to the front support shaft at one location, and the rear portion of the center member is attached to the rear support shaft at two locations.

[0012] In the vehicle seat structure according to claim 3, the front portion of the center member is attached to the front support shaft at only one location. This reduces interference with surrounding components compared to a configuration in which the center member is attached at multiple locations. Furthermore, the rear portion of the center member, which receives a greater load than the front portion, is attached to the rear support shaft at two locations. This maintains a better attachment state between the center member and the rear support shaft compared to a configuration in which the center member is attached at only one location.

[0013] The vehicle seat structure according to claim 4 is the same as claim 1, except that a front flange is provided on the outer peripheral surface of the front support shaft to limit movement of the front part of the center member in the seat width direction, and a rear flange is provided on the outer peripheral surface of the rear support shaft to limit movement of the rear part of the center member in the seat width direction.

[0014] In the vehicle seat structure according to claim 4, the movement of the front portion of the center member in the seat width direction is limited by the front flange of the front support shaft, and the movement of the rear portion of the center member in the seat width direction is limited by the rear flange of the rear support shaft, thereby making it possible to limit the movement of the center member in the seat width direction with a simple structure.

[0015] The vehicle seat structure according to claim 5 is any one of claims 1 to 4, wherein a front collar member having a smaller friction coefficient than the front support shaft is provided at the contact portion of the front support shaft with the front portion of the center member, and a rear collar member having a smaller friction coefficient than the rear support shaft is provided at the contact portion of the rear support shaft with the rear portion of the center member.

[0016] In the vehicle seat structure according to claim 5, the front collar member has a smaller coefficient of friction than the front support shaft, and the rear collar member has a smaller coefficient of friction than the rear support shaft. This means that the swinging of the center member relative to the front support shaft and the rear support shaft is less restricted than in a configuration in which the center member is attached directly to the front support shaft and the rear support shaft. [Effects of the Invention]

[0017] As described above, according to the vehicle seat structure of the present invention, in a configuration in which the seat cushion can be swung in the seat width direction by the leaf spring, the function of the leaf spring can be maintained well even when the support shaft rotates. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an enlarged perspective view showing a vehicle seat according to an embodiment; [Figure 2] 2 is an enlarged perspective view of the vehicle seat of FIG. 1 as viewed from a different angle. [Figure 3] FIG. 2 is an enlarged perspective view showing a main part of a support mechanism according to the embodiment. [Figure 4] FIG. 2 is a plan view showing a main part of a support mechanism according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] A vehicle seat structure according to an embodiment will be described with reference to the drawings.

[0020] Fig. 1 is an enlarged perspective view showing a vehicle seat 10 to which a vehicle seat structure according to an embodiment is applied. Specifically, it is a perspective view of a lower frame of the vehicle seat 10 as seen from the rear left of the seat. Fig. 2 is an enlarged perspective view of the vehicle seat 10 of Fig. 1 as seen from a different angle. Note that the arrows FR, UP, and RH in the figure indicate the seat front direction, seat upper direction, and seat right direction of the vehicle seat 10, respectively. 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 seat front-rear direction, up-down in the seat up-down direction, and left-right in the seat width direction, respectively.

[0021] As shown in Figures 1 and 2, a vehicle seat 10 to which the vehicle seat structure of this embodiment is applied is a seat installed in a vehicle cabin, and is configured to include a seat back 14 that can support the back of an occupant from the rear side of the seat, and a seat cushion 12 that can support the buttocks and thighs of the occupant from the underside of the seat.

[0022] The seat back 14 includes a pair of left and right seat back side frames 16 spaced apart in the seat width direction, and a seat back lower frame 18 that connects the lower ends of the seat back side frames 16 in the seat width direction. In addition, a seat back upper frame (not shown) that connects the upper ends of the seat back side frames 16 in the seat width direction is provided at the upper end of the seat back 14, and a headrest (not shown) that can support the head of an occupant is provided at the top of the seat back 14.

[0023] A pair of left and right seatback side frames 16 are arranged parallel to each other, and the lower ends of the seatback side frames 16 are rotatably connected to the seat cushion 12. Although not shown, a seatback pad (not shown) is provided between the left and right seatback side frames 16, and this seatback pad supports the back of the occupant. The seatback pad, together with the seatback side frames 16 and the seatback lower frame 18, is used covered with a skin that forms the design surface.

[0024] The seat cushion 12 includes a seat cushion frame 20 that forms a skeleton, and the seat cushion frame 20 includes a seat cushion front frame 20A that extends in the seat width direction at the front end of the seat.

[0025] The seat cushion side frames 20B extend from both end portions of the seat width direction of the seat cushion front frame 20A toward the rear side of the seat. Therefore, the seat cushion frame 20 is formed by the seat cushion front frame 20A and the left and right seat cushion side frames 20B into a substantially U-shape in plan view with the rear side of the seat open.

[0026] Here, the rear end portions of the seat cushion side frames 20B are connected to each other in the seat width direction by rear support shafts 34. The front end portions of the seat cushion side frames 20B are connected to each other in the seat width direction by front support shafts 36. The rear support shafts 34 and the front support shafts 36 will be described in detail later.

[0027] A pair of left and right seat rails 22 are arranged below the seat cushion 12. Each seat rail 22 includes a lower rail 22A and an upper rail 22B, and the lower rail 22A is fixed to a floor panel (not shown) that forms the floor of the vehicle interior.

[0028] The lower rails 22A extend in the front-rear direction of the seat, and the upper rails 22B are disposed inside the lower rails 22A. The upper rails 22B extend in the front-rear direction of the seat like the lower rails 22A, and are movable in the front-rear direction of the seat relative to the lower rails 22A.

[0029] A front bracket 24 is attached to the front of the upper rail 22B, and a rear bracket 26 is attached to the rear of the upper rail 22B. The front bracket 24 is connected to the front of the seat cushion frame 20 via a front link 28, and the rear bracket 26 is connected to the rear of the seat cushion frame 20 via a rear link 30. Therefore, the seat cushion 12 can be moved in the front-rear direction of the seat by moving the upper rail 22B relative to the lower rail 22A in the front-rear direction of the seat.

[0030] The front link 28 is formed in a flat plate shape, and the lower end of the front link 28 is rotatably attached to the front bracket 24. In addition, the upper end of the front link 28 is rotatably attached to the seat cushion frame 20.

[0031] The rear link 30 is formed in a flat plate shape, and the lower end of the rear link 30 is rotatably attached to the rear bracket 26. In addition, the upper end of the rear link 30 is rotatably attached to the seat cushion frame 20.

[0032] Here, a motor (not shown) is connected to at least one of the rotation shafts of the front link 28 and the rear link 30, and is configured so that when driven by the motor, the front link 28 and the rear link 30 rotate to move up and down the seat cushion frame 20. Note that instead of a motor, a lift-up mechanism that allows the occupant to manually rotate the front link 28 and the rear link 30 may be employed.

[0033] A cushion pan 32 is disposed inside the seat cushion frame 20. The cushion pan 32 includes a frame portion 32A having a generally rectangular outer shape and a plurality of elongated seat panels 32B provided inside the frame portion 32A. The cushion pan 32 is supported by the seat cushion frame 20 via a support mechanism 38.

[0034] (Support mechanism 38) The support mechanism 38, which is a main part of the present invention, will now be described.

[0035] 3, the support mechanism 38 includes a center member 40, a rear leaf spring 64, and a front leaf spring 68. The center member 40 is provided below the seat cushion frame 20 and in the center in the seat width direction, and is an elongated member extending in the front-to-rear direction of the seat, and is made of a highly rigid material.

[0036] The rear portion of the center member 40 extends obliquely above and toward the rear of the seat, and a rear base 44 is provided at the rear end of the center member 40. The rear base 44 extends in the seat width direction, and rear lower rings 48 are provided at both end portions of the rear base 44 in the seat width direction.

[0037] The rear lower ring 48 is formed in a generally arcuate shape and is joined to the rear base 44 by welding or the like. The rear lower ring 48 is also disposed along the outer periphery of the lower side of the rear support shaft 34.

[0038] As shown in FIG. 4, screw holes 48A are formed on both end surfaces of the rear lower ring 48, and as shown in FIG. 3, a rear upper ring 52 is attached to the rear lower ring 48, and the rear lower ring 48 and the rear upper ring 52 are fastened together with bolts while sandwiching the rear support shaft 34.

[0039] Here, the outer peripheral surface of the rear support shaft 34 is provided with a rear flange 34A that limits movement of the rear portion of the center member 40 in the seat width direction.

[0040] As shown in Fig. 4, two rear flanges 34A are provided spaced apart in the seat width direction, and each is formed in a generally annular shape. A rear collar member 34B is formed integrally with the rear flange 34A. The rear collar member 34B is fixed to the rear support shaft 34, and the surface of the rear collar member 34B has a smaller coefficient of friction than the rear support shaft 34. Because the rear collar member 34B is provided in a portion that comes into contact with the rear lower ring 48 and the rear upper ring 52, the friction force generated between the rear lower ring 48 and the rear upper ring 52 and the rear support shaft 34 is small.

[0041] 1 and 3, one end (upper end) of a rear leaf spring 64 is fixed to the rear lower ring 48. The rear leaf spring 64 is fixed to each of the pair of left and right rear lower rings 48 and is formed in the shape of a long, flat plate with its thickness direction aligned with the seat width direction. In other words, the rear leaf spring 64 is provided so as to be elastically deformable in the seat width direction.

[0042] The pair of rear leaf springs 64 each extend obliquely from the rear lower ring 48 downward and rearward of the seat, and the lower end of the rear leaf spring 64 is fastened to the lower end of the rear connecting member 62.

[0043] The rear connecting member 62 has higher rigidity than the rear leaf spring 64, and is disposed so as to incline from the rear leaf spring 64 toward the front and upper side of the seat when viewed in the seat width direction. The upper end of the rear connecting member 62 is fixed to the rear end of the frame portion 32A of the cushion pan 32. As a result, when an external force in the seat width direction is applied to the cushion pan 32 by an occupant seated in the vehicle seat 10, the rear leaf spring 64 elastically deforms, thereby applying a restoring reaction force to the rear portion of the cushion pan 32 while allowing movement of the rear portion of the cushion pan 32 in the seat width direction.

[0044] Additionally, the rear leaf spring 64 applies an external force to the rear lower ring 48 and the rear upper ring 52, causing them to move in the seat width direction, but the rear lower ring 48 and the rear upper ring 52 are locked by the rear flange 34A, limiting their movement in the seat width direction. Meanwhile, the rear portion of the center member 40 is attached to the rear support shaft 34 via the rear collar member 34B, allowing the center member 40 to rotate about the axis of the rear support shaft 34.

[0045] 2 and 3, the front portion of the center member 40 extends obliquely above and toward the front of the seat, and a front base 46 is provided at the front end of the center member 40. The front base 46 extends in the seat width direction, and one end of a front leaf spring 68 is fastened to each of the two end portions of the front base 46 in the seat width direction.

[0046] A pair of front leaf springs 68 are provided on the left and right, and the front leaf springs 68 are inclined downward from the inside in the seat width direction to the outside in the seat width direction when viewed from the front of the seat. Also, the front leaf springs 68 are inclined downward from the front side of the seat to the rear side when viewed from the seat width direction, and are configured to be elastically deformable in the seat width direction.

[0047] The lower end of the front connecting member 66 is fastened to the lower end of the front leaf spring 68. The front connecting member 66 has higher rigidity than the front leaf spring 68 and extends outward in the seat width direction and toward the upper side of the seat from the front leaf spring 68. In addition, the upper end of the front connecting member 66 is fixed to the front end of the frame portion 32A of the cushion pan 32.

[0048] 4, a front lower ring 50 is provided on the center member 40, further rearward of the seat than the front base 46. The front lower ring 50 is formed in a generally arcuate shape and is joined to the center member 40 by welding or the like. The front lower ring 50 is also disposed along the outer periphery of the lower side of the front support shaft 36.

[0049] Screw holes 50A are formed on both end surfaces of the front lower ring 50, and as shown in Figure 2, a front upper ring 54 is attached to the front lower ring 50, and the front lower ring 50 and the front upper ring 54 are fastened together with bolts while sandwiching the front support shaft 36.

[0050] Here, the outer peripheral surface of the front support shaft 36 is provided with a front flange 36A that limits movement of the front part of the center member 40 in the seat width direction.

[0051] As shown in FIG. 4, two front flanges 36A are provided at an interval in the seat width direction and on the inner side of the rear flange 34A in the seat width direction, and each is formed in a substantially annular shape. A front collar member 36B is formed integrally with the front flange 36A. The front collar member 36B is fixed to the front support shaft 36, and the surface of the front collar member 36B has a smaller coefficient of friction than the front support shaft 36. The front collar member 36B is provided in a portion that comes into contact with the front lower ring 50 and the front upper ring 54, and therefore the frictional force generated between the front lower ring 50, the front upper ring 54, and the front support shaft 36 is small.

[0052] As a result, when an external force in the seat width direction is input to the cushion pan 32 by an occupant seated in the vehicle seat 10, the rear leaf spring 64 elastically deforms, allowing the rear of the cushion pan 32 to move in the seat width direction, while applying a restoring reaction force to the rear of the cushion pan 32.

[0053] Additionally, an external force acts on the front lower ring 50 and the front upper ring 54 by the front leaf spring 68, causing them to move in the seat width direction, but the front lower ring 50 and the front upper ring 54 are locked by the front flange 36A, limiting their movement in the seat width direction. Meanwhile, because the front portion of the center member 40 is attached to the front support shaft 36 via the front collar member 36B, the center member 40 is rotatable about the axis of the front support shaft 36.

[0054] As described above, the front portion of the center member 40 and the seat cushion 12 are connected via the front leaf spring 68, and the rear portion of the center member 40 and the seat cushion 12 are connected via the rear leaf spring 64. The front portion of the center member 40 is attached to the front support shaft 36 at one location, and the rear portion of the center member 40 is attached to the rear support shaft 34 at two locations.

[0055] (action) Next, the operation of the vehicle seat structure according to this embodiment will be described.

[0056] 1 to 3, in the vehicle seat structure according to this embodiment, a center member 40 is provided below the seat cushion 12 and in the center in the seat width direction, and the front and rear portions of the center member 40 are connected to the seat cushion 12 by a rear leaf spring 64 and a front leaf spring 68, respectively. As a result, when a load is input to the seat cushion 12, the rear leaf spring 64 and the front leaf spring 68 elastically deform, thereby maintaining a good posture of the seated occupant.

[0057] In addition, a front support shaft 36 is provided at the front of the seat cushion 12, and a rear support shaft 34 is provided at the rear of the seat cushion 12, with the front support shaft 36 and the rear support shaft 34 extending in the seat width direction.

[0058] Here, the front portion of the center member 40 is attached so as to be rotatable about the axis of the front support shaft 36 but immovable in the seat width direction. In addition, the rear portion of the center member 40 is attached so as to be rotatable about the axis of the rear support shaft 34 but immovable in the seat width direction. As a result, even when the seat cushion 12 is moved up and down by rotating the front support shaft 36 and the rear support shaft 34, the angles of the front leaf springs 68 and the rear leaf springs 64 do not change. In other words, in a configuration in which the seat cushion 12 can be oscillated in the seat width direction by the leaf springs, the function of the leaf springs can be maintained well even when the support shafts are rotated.

[0059] Furthermore, because the front leaf springs 68 and the rear leaf springs 64 are connected via the center member 40, a total of four leaf springs, namely the two front leaf springs 68 and the two rear leaf springs 64, can be elastically deformed in the same manner. In other words, the relative angle between the oscillation angle of the pair of front leaf springs 68 and the oscillation angle of the pair of rear leaf springs 64 can be prevented from changing. As a result, the front leaf springs 68 and the rear leaf springs 64 can be prevented from elastically deforming independently.

[0060] In particular, in this embodiment, the above-mentioned four leaf springs are provided at the four corners of the seat cushion 12, which makes it easier for the leaf springs to follow the movement of the seat cushion 12 compared to a structure in which the leaf springs are arranged in the center part of the seat cushion 12.

[0061] Furthermore, in this embodiment, the front portion of the center member 40 is attached to the front support shaft 36 at only one location, which reduces interference with surrounding components compared to a configuration in which the front portion of the center member 40 and the front support shaft 36 are attached at multiple locations.

[0062] Meanwhile, because the rear portion of the center member 40, which receives a greater load than the front portion, is attached to the rear support shaft 34 at two locations, the attachment state between the center member 40 and the rear support shaft 34 can be maintained better than in a configuration in which the rear portion of the center member 40 is attached to the rear support shaft 34 at only one location. In other words, because the rear portion of the center member 40 receives a greater load from the occupant than the front portion, distributing the load at multiple locations prevents damage to the attachment portion between the center member 40 and the rear support shaft 34.

[0063] 4, the movement of the front portion of the center member 40 in the seat width direction is limited by the front flange 36A of the front support shaft 36, and the movement of the rear portion of the center member 40 in the seat width direction is limited by the rear flange 34A of the rear support shaft 34. This makes it possible to limit the movement of the center member 40 in the seat width direction with a simple structure.

[0064] Furthermore, in this embodiment, the front collar member 36B has a smaller coefficient of friction than the front support shaft 36, and the rear collar member 34B has a smaller coefficient of friction than the rear support shaft 34. As a result, compared to a configuration in which the center member 40 is attached directly to the front support shaft 36 and the rear support shaft 34, the center member 40 is less likely to be restricted from swinging relative to the front support shaft 36 and the rear support shaft 34. In other words, the center member 40 can be smoothly swung relative to the front support shaft 36 and the rear support shaft 34.

[0065] While the vehicle seat structure according to the embodiment has been described above, it is needless to say that it can be embodied in various forms without departing from the spirit of the present invention. For example, while the above embodiment is provided with a lift-up mechanism that can move the seat cushion 12 up and down, the present invention is not limited to this and may be applied to a vehicle seat 10 that does not have a lift-up mechanism.

[0066] In addition, in the above embodiment, the seat cushion 12 is supported so as to be swingable in the seat width direction by a pair of front leaf springs 68 and a pair of rear leaf springs 64, but this is not limited to this, and the seat cushion 12 may be supported so as to be swingable in the seat width direction by other members instead of the leaf springs.

[0067] Furthermore, in the above embodiment, the rear portion of the center member 40 is attached to be rotatable about the axis of the rear support shaft 34 by sandwiching the rear support shaft 34 between the rear lower ring 48 and the rear upper ring 52, but this is not limited to this and other configurations may be used. Similarly, in the above embodiment, the front portion of the center member 40 is attached to be rotatable about the axis of the front support shaft 36 by sandwiching the front support shaft 36 between the front lower ring 50 and the front upper ring 54, but this is not limited to this and other configurations may be used. For example, the rear portion of the center member 40 may be connected to the rear support shaft 34 via a bearing or the like, so that the rear portion of the center member 40 is rotatable about the axis of the rear support shaft 34.

[0068] The following notes are provided regarding the above embodiment.

[0069] (Appendix 1) a seat cushion that supports the buttocks and thighs of an occupant from below; a center member provided below the seat cushion and at a center portion in a seat width direction, the center member extending in a seat front-rear direction; leaf springs connecting the front and rear portions of the center member to the seat cushion; a front support shaft provided at a front portion of the seat cushion, constituting a framework of the seat cushion and extending in a seat width direction; a rear support shaft provided at a rear portion of the seat cushion, constituting a framework of the seat cushion, and extending in a seat width direction; and a front portion of the center member is attached to the front support shaft so as to be rotatable about the axis of the front support shaft and so as not to be movable in the seat width direction; The rear portion of the center member is attached so as to be rotatable about the axis of the rear support shaft but not movable in the seat width direction. (Appendix 2) 2. The vehicle seat structure according to claim 1, wherein the leaf springs are configured to be elastically deformable in the seat width direction and are provided at four corners of the seat cushion. (Appendix 3) The front portion of the center member is attached to the front support shaft at one location, 3. The vehicle seat structure according to claim 1, wherein the rear portion of the center member is attached to the rear support shaft at two locations. (Appendix 4) a front flange portion is provided on an outer peripheral surface of the front support shaft to limit movement of a front portion of the center member in the seat width direction; The vehicle seat structure according to any one of Supplementary Note 1 to Supplementary Note 3, wherein a rear flange portion is provided on the outer peripheral surface of the rear support shaft to limit movement of the rear portion of the center member in the seat width direction. (Appendix 5) a front collar member having a smaller coefficient of friction than the front support shaft is provided at a contact portion of the front support shaft with the front portion of the center member, The vehicle seat structure according to any one of appendix 1 to appendix 4, wherein a rear collar member having a smaller coefficient of friction than the rear support shaft is provided at a contact portion of the rear support shaft with the rear portion of the center member. [Explanation of symbols]

[0070] 10 Vehicle seats 12 seat cushions 34 Rear support shaft 34A Rear flange 34B Rear collar member 36 Front support shaft 36A Front flange 36B Front collar member 40 Center member 64 Front leaf spring 68 Rear leaf spring

Claims

1. a seat cushion that supports the buttocks and thighs of an occupant from below; a center member provided below the seat cushion and at a center portion in a seat width direction, the center member extending in a seat front-rear direction; leaf springs connecting the front and rear portions of the center member to the seat cushion; a front support shaft provided at a front portion of the seat cushion, constituting a framework of the seat cushion and extending in a seat width direction; a rear support shaft provided at a rear portion of the seat cushion, constituting a framework of the seat cushion, and extending in a seat width direction; and a front portion of the center member is attached to the front support shaft so as to be rotatable about the axis of the front support shaft and so as not to be movable in the seat width direction; The rear portion of the center member is attached so as to be rotatable about the axis of the rear support shaft but not movable in the seat width direction.

2. 2. The vehicle seat structure according to claim 1, wherein the leaf springs are configured to be elastically deformable in the seat width direction and are provided at four corners of the seat cushion.

3. The front portion of the center member is attached to the front support shaft at one location, 2. The vehicle seat structure according to claim 1, wherein the rear portion of the center member is attached to the rear support shaft at two locations.

4. a front flange portion is provided on an outer peripheral surface of the front support shaft to limit movement of a front portion of the center member in the seat width direction; 2. The vehicle seat structure according to claim 1, wherein a rear flange is provided on an outer peripheral surface of the rear support shaft to limit movement of the rear portion of the center member in the seat width direction.

5. a front collar member having a smaller coefficient of friction than the front support shaft is provided at a contact portion of the front support shaft with the front portion of the center member, 5. The vehicle seat structure according to claim 1, wherein a rear collar member having a smaller coefficient of friction than the rear support shaft is provided at a contact portion of the rear support shaft with the rear portion of the center member.

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