Seat support device, method for manufacturing seat support device, and vehicle seat

Abstract

To adjust urging force of an urging member which returns a seat back from a collapse state to a stand-up state easily.SOLUTION: A seat support device comprises a seat cushion, a seat back, and a support part SP which turnably supports the seat back with an axis line L2 extending in a substantially horizontal direction as the center within a prescribed turning scope containing positions from a collapse position in which the seat back is collapsed to a stand-up position. The support part SP includes a first spiral spring 41 and a second spiral spring 42 which urge the seat back situated in the collapse position to a stand-up direction, and a lock mechanism of a reclining mechanism 30 which retains the seat back in the collapse position by opposing against urging force of the first spiral spring 41 and the second spiral spring 42. The first spiral spring 41 and the second spiral spring 42 are configured so as to have urging force different from each other.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a seat support device that rotatably supports a seat back, and a method for manufacturing the seat support device.

Background Art

[0002] Conventionally, a device that rotatably supports a seat back with respect to a seat cushion via a spiral spring has been known (see, for example, Patent Document 1). The device described in this Patent Document 1 has a spiral spring whose one end and the other end are respectively locked to the seat cushion side and the seat back side, and the seat back locked in the forwardly tilted state against the biasing force of the spiral spring automatically stands up by the biasing force of the spiral spring when the lock is released.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a device that automatically stands up a seat back in a tilted-back state (forwardly tilted state) tilted forward against the biasing force of a biasing member (spiral spring), such as the device described in Patent Document 1, it is difficult to adjust the biasing force of the biasing member.

Means for Solving the Problems

[0005] One aspect of the present invention, a seat support device, includes a seat cushion, a seat back connected to the rear end of the seat cushion, and a support portion disposed below the connection point between the seat cushion and the seat back. The support portion rotatably supports the seat back about an axis extending substantially horizontally within a predetermined rotation range including the upright position from the reclined position where the seat back is reclined. The support portion has a biasing member that biases the seat back in the upright direction and a locking mechanism that holds the seat back in the reclined position against the biasing force of the biasing member. The biasing member is composed of a first biasing member and a second biasing member that bias the seat back in the upright direction with different biasing forces. The first biasing member and the second biasing member each have a width with a predetermined length substantially parallel to the axis, and are constituted by spiral springs wound radially outward. The support portion projects substantially parallel to the axis from the seat back, and further includes a holding portion that holds the radially outer end portions of the first biasing member and the second biasing member, respectively. The holding portion has a first concave portion formed in a concave shape over the width direction of the first biasing member so that the radially outer end portion of the first biasing member is held, and a second concave portion formed in a concave shape over the width direction of the second biasing member so that the radially outer end portion of the second biasing member is held. The first concave portion and the second concave portion are provided at different positions in the rotation direction of the seat back.

[0006] Another aspect of the present invention is a seat support device including a seat cushion, a seat back connected to the rear end of the seat cushion, and a support portion disposed below the connection point between the seat cushion and the seat back. The support portion rotatably supports the seat back about an axis extending substantially horizontally within a predetermined rotation range including the upright position from the reclined position where the seat back is reclined. The support portion has a first biasing member and a second biasing member that bias the seat back in the upright direction with different biasing forces, and a locking mechanism that holds the seat back in the reclined position against the biasing forces of the first biasing member and the second biasing member. It has a holding portion that projects substantially parallel to the axis from the seat back and holds the radially outer end portions of the first biasing member and the second biasing member, respectively. The holding portion has a first concave portion formed in a concave shape over the width direction of the first biasing member so that the radially outer end portion of the first biasing member is held, and a second concave portion formed in a concave shape over the width direction of the second biasing member so that the radially outer end portion of the second biasing member is held. A method for manufacturing a seat support device having the above components. The method for manufacturing a seat support device includes a step of rotatably attaching a seat back to a seat cushion about an axis, a step of attaching a locking mechanism to a side surface of the seat cushion, a step of attaching a spiral first biasing member about the axis In the first concave portion and a step of further attaching a spiral second biasing member about the axis. In the second concave portion

Advantages of the Invention

[0007] According to the present invention, the biasing force of the biasing member that returns the seat back from the reclined state to the upright state can be easily adjusted.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10A

Figure 10B

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 10B. The seat support device according to an embodiment of the present invention is applied to, for example, a vehicle seat as a vehicle seat, particularly a rear seat facing a back door provided at the rear of the vehicle. Note that the seat support device can also be applied to a front seat of a vehicle and can also be applied to other vehicle seats. Further, it can also be applied to seats other than vehicle seats.

[0010] FIG. 1 is a side view showing a schematic configuration of a rear seat (hereinafter simply referred to as a seat) 100 for a vehicle to which the seat support device according to the present embodiment is applied. As shown in FIG. 1, the seat 100 includes a seat cushion 1 that supports the buttocks of an occupant, a seat back 2 that supports the waist and back of the occupant, and a headrest 3 that supports the head of the occupant. Hereinafter, the front-rear direction, the left-right direction, and the up-down direction are defined based on the occupant seated on the seat 100, and the configuration of each part will be described according to this definition.

[0011] On the upper surface of the vehicle floor 4, a pair of left and right lower rails 5 extending in the front-rear direction are fixed. Above the lower rail 5, a pair of left and right upper rails 6 extending in the front-rear direction are provided. The upper rail 6 is slidable in the front-rear direction on the lower rail 5, and the lower rail 5 and the upper rail 6 constitute a slide mechanism 7.

[0012] The seat 100 has a seat frame 101 that forms the skeleton of the seat 100. FIG. 2 is a perspective view of the seat frame 101 that forms the skeleton of the seat 100, showing a state in which the skin, pads, etc. of the seat 100 are removed from FIG. 1. As shown in FIG. 2, the seat frame 101 includes a seat cushion frame 10 that forms the skeleton of the seat cushion 1 and a seat back frame 20 that forms the skeleton of the seat back 2. The seat cushion frame 10 has a pair of left and right lower frames 11 extending in the front-rear direction and a pair of front and rear connecting frames 12 and 13 extending in the left-right direction and connecting the left and right lower frames 11 to each other, and is configured in a frame shape in plan view as a whole. The front end portions of the left and right lower frames 11 are supported by a pair of left and right leg frames 14 erected on the upper rail 6. Note that the upper end portion and the lower end portion of the leg frame 14 are pivotally supported on the lower frame 11 and the upper rail 6, respectively, so as to be rotatable about a rotation axis extending in the left-right direction.

[0013] The seat back frame 20 includes a substantially rectangular frame 20a in a front view, which is composed of a pair of left and right side frames 21 extending in the vertical direction and a pair of upper and lower connecting frames 22 and 23 extending in the horizontal direction and connecting the left and right side frames 21, and a substantially rectangular plate-shaped back panel 24 fixed to the rear surface of the frame 20a. At the lower ends of the left and right side frames 21, substantially plate-shaped upper brackets 25 are respectively fixed. The upper bracket 25 extends downward from the connecting frame 23, is formed wide in the front-rear direction, and has a pair of left and right side surfaces 25a facing outward in the left-right direction.

[0014] The left and right lower frames 11 of the seat cushion frame 10 are arranged outside the left and right side surfaces 25a of the left and right upper brackets 25 with a gap in the left-right direction. At the lower end of the upper bracket 25, the rear end of the lower frame 11 is pivotally supported about a pivot shaft 26 extending along the left-right axis L1. The left and right lower frames 11 are located at substantially the same position in the left-right direction as the left and right upper rails 6. At the rear ends of the left and right upper rails 6, a pair of left and right lower brackets 15 projecting upward in a substantially plate shape are provided. The left and right lower brackets 15 are integrally connected by a connecting frame 16 extending in the left-right direction.

[0015] The seat back frame 20 is pivotally supported by the lower brackets 15 about an axis L2 extending in the left-right direction. That is, a support portion SP is provided at the upper end of the lower bracket 15, and the upper bracket 25 is pivotally supported by the support portion SP. As shown in FIG. 1, the angle (tilt angle θ) of the seat back 2 with respect to the horizontal line is changed via the support portion SP.

[0016] Figures 3A and 3B are diagrams showing an example of the pivoting operation of the seat back 2. In particular, Figure 3B shows the state where the seat back 2 is pivoted forward to the maximum extent, and Figure 3A shows the state during the pivoting of the seat back 2. The position of the seat back 2 in Figure 1 is called the upright position, and the position of the seat back 2 in Figure 3B is called the reclined position (storage position). In the upright position, the tilt angle θ is approximately 90 degrees (strictly about 100 - 110 degrees), and in the reclined position, the tilt angle θ is approximately 0 degrees. The seat back 2 is pivotable forward about the axis L2 from the upright position to the reclined position. Specifically, as shown in Figure 3A, during the pivoting of the seat back 2, the leg frame 14 is folded in the direction of arrow A, and accordingly, the seat cushion 1 moves in the direction of arrow B (forward), so that the seat back 2 can be pivoted to the reclined position shown in Figure 3B.

[0017] Figure 4 is a plan view (a cross-sectional view taken along line IV-IV in Figure 2) schematically showing the state of the support portion SP in Figure 2 as viewed from above. As shown in Figure 4, the support portion SP has a reclining mechanism 30 that tilts the seat back 2 (upper bracket 25) and locks it in the reclined position and the upright position, and a return mechanism 40 that returns the seat back 2 with the lock released in the reclined position to the upright position. The reclining mechanism 30 is provided between the right side surface 25a of the right upper bracket 25 and the left side surface 15a of the right lower bracket 15 about the axis L2. The return mechanism 40 is provided on the right side surface 15b of the right lower bracket 15 about the axis L2.

[0018] FIG. 5 is a front view (a sectional view taken along the line V-V in FIG. 4) showing a schematic configuration of the reclining mechanism 30 having a lock mechanism. As shown in FIG. 5, the reclining mechanism 30 includes a lower plate 31 fixed to the left side surface 15a of the lower bracket 15, an upper plate 32 fixed to the right side surface 25a of the upper bracket 25 and disposed opposite to the lower plate 31, a connecting shaft 33 extending along the axis L2 and passing through the rotation centers of the lower plate 31 and the upper plate 32, a cam plate 34 disposed in the internal space between the lower plate 31 and the upper plate 32 and rotating integrally with the connecting shaft 33, a pair of upper and lower lock members 35 disposed in the internal space, and a pair of torsion springs 36 urging the cam plate 34 in the direction of arrow A.

[0019] The lock member 35 engages with a guide groove 31a formed on the left surface of the lower plate 31 and is configured to be movable in the vertical direction, that is, in the radially inner and outer directions, along the guide groove 31a. The lock member 35 has a cam portion on the inner diameter side end surface and external teeth 35a on the outer diameter side end surface. The upper plate 32 has internal teeth 32a formed over the circumferential direction on the inner circumferential surface forming the internal space. The external teeth 35a of the lock member 35 engage with the internal teeth 32a of the upper plate 32 when moving radially outward. The cam plate 34 engages with the lock member 35, and when the cam plate 34 is rotated in the direction of arrow A by the urging force of the torsion spring 36 as shown in the figure, the lock member 35 is moved radially outward. Thereby, the external teeth 35a mesh with the internal teeth 32a, and the rotational position of the upper bracket 25 with respect to the lower bracket 15 is fixed (reclining lock).

[0020] On the other hand, when the cam plate 34 is rotated in the direction of arrow B against the urging force of the torsion spring 36, the lock member 35 is moved radially inward. Thereby, the external teeth 35a are separated from the internal teeth 32a, and relative rotation of the upper bracket 25 with respect to the lower bracket 15 becomes possible (reclining lock release). The connecting shaft 33 passes through the upper bracket 25, and a release lever 37 is joined to the left end thereof. An operation strap is locked to the release lever 37 via a link mechanism.

[0021] FIG. 6 is a perspective view showing the configuration of the operation straps, that is, a perspective view of the seat frame 101 viewed obliquely from the rear. As shown in FIG. 6, the front ends of a pair of left and right connection frames 17 extending in the front-rear direction are fixed to a connection frame 16 extending between the left and right lower brackets 15 by welding or the like. At the rear ends of the left and right connection frames 17, a connection pipe 18 extending in the left-right direction is fixed by welding or the like. At a substantially central portion in the left-right direction of the connection pipe 18, a tether anchor 19 for fixing the child seat is fixed. At the lower end of the connection pipe to which the tether anchor 19 is fixed by welding or the like, a pair of left and right strap support wires 191, 192 formed in a substantially U shape facing rearward are joined. A wire pipe 193 extending in the left-right direction is joined to the bottom surfaces of the strap support wires 191, 192.

[0022] Between the strap support wires 191, 192 and the wire pipe 193, a pair of left and right operation straps 8, 9 are respectively inserted. Among the operation straps 8, 9, one (for example, the operation strap 8) is an operation strap for unlocking the slide mechanism 7 (FIG. 1), and the other (for example, the operation strap 9) is an operation strap for unlocking the reclining mechanism 30. The operation straps 8, 9 extend in the front-rear direction below the seat cushion frame 10, and operation portions 8a, 9a gripped by the user are provided upward at their rear ends. Link mechanisms (not shown) are respectively connected to the front ends of the operation straps 8, 9. Spring biasing forces that lock the slide mechanism 7 and the reclining mechanism 30 always act on the link mechanisms, and the operation straps 8, 9 are biased forward (the operation portions 8a, 9a are biased downward).

[0023] When the user pulls up the operation part 8a of the operation strap 8 against the biasing force of the spring, for example, with the back door released, the lock of the slide mechanism 7 is released via the link mechanism. As a result, the upper rail 6 can slide on the lower rail 5. Also, when the user pulls up the operation part 9a of the operation strap 9 against the biasing force of the spring, the connecting shaft 33 is rotated in the direction of arrow B in FIG. 5 via the link mechanism. Thereby, the lock of the reclining mechanism 30 is released, and the seat back 2 (upper bracket 25) becomes rotatable.

[0024] Although not shown, a release cable is connected to the link mechanism connected to the operation strap 9. As shown in FIG. 2, the release cable 90 extends vertically along the space on the right side of the right side frame 21, and its upper end is connected to an operation part 9b (see FIG. 1) protruding from the upper end of the seat back frame 20. When the operation part 9b is pulled, the connecting shaft 33 is rotated in the direction of arrow B in FIG. 5 via the release cable 90 and the link mechanism. Thus, the user can release the lock of the reclining mechanism 30 not only by pulling up the operation part 9a but also by pulling up the operation part 9b. For example, a user standing on the right side of the seat 100 can release the lock of the reclining mechanism 30 by operating the operation part 9b.

[0025] As shown in Fig. 5, a pair of upper and lower lock members 35 are provided with cam pins 35b protruding toward the left (the side of the upper plate 32). On the upper plate 32, a substantially cylindrical inner peripheral surface 32b centered on the axis L2 is formed corresponding to the position of the cam pin 35b. Fig. 7 is a view showing the relationship between the cam pin 35b and the inner peripheral surface 32b (a plan view showing the main part configuration of the locking mechanism of the reclining mechanism 30 in Fig. 5). As shown in Fig. 7, the inner peripheral surface 32b has a substantially circular first inner peripheral surface 32b1 and a second inner peripheral surface 32b2 centered on the axis L2. The first inner peripheral surface 32b1 and the second inner peripheral surface 32b2 are provided in pairs alternately in the circumferential direction. The second inner peripheral surface 32b2 has a smaller diameter than the first inner peripheral surface 32b1. When the seat back 2 is in the upright position (Fig. 1), the cam pin 35b engages with one end in the circumferential direction (position P1) of the first inner peripheral surface 32b1 as shown in Fig. 7. At this time, the external teeth 35a of the lock member 35 mesh with the internal teeth 32a of the upper plate 32, and the seat back 2 is locked in the upright position.

[0026] From this state, when the lock of the reclining mechanism 30 is released by operating the operation parts 9a, 9b and the upper plate 32 is rotated in the direction of arrow B in Fig. 7, the cam pin 35b engages with the second inner peripheral surface 32b2. As a result, the lock member 35 moves radially inward, the external teeth 35a are separated from the internal teeth 32a, and the lock of the reclining mechanism 30 is released. In this case, even if the operation of the operation parts 9a, 9b is stopped, the external teeth 35a remain separated from the internal teeth 32a, and the released state is maintained. When the seat back 2 rotates to the reclined position, the cam pin 35b engages with the circumferential end (position P0) of the first inner peripheral surface 32b1. As a result, the lock member 35 moves radially outward by the biasing force of the torsion spring 36 (Fig. 5), the external teeth 35a mesh with the internal teeth 32a, and the seat back 2 is locked in the reclined position.

[0027] When the lock of the reclining mechanism 30 is released by operating the operation parts 9a, 9b with the seat back 2 in the reclined position, the seat back 2 rotates in the direction of arrow A in Fig. 7 by the return mechanism 40 and is locked in the upright position.

[0028] FIG. 8 is a perspective view (standing position) of the main part configuration of the return mechanism 40 as viewed obliquely from the front, and FIG. 9 is a perspective view (rewinding position) as viewed obliquely from the rear. As shown in FIGS. 8 and 9, the return mechanism 40 includes a first spiral spring 41 and a second spiral spring 42 having different biasing forces from each other, and a holding portion 43 that holds the tip of the first spiral spring 41 and the tip of the second spiral spring 42, respectively. The first spiral spring 41 is disposed on the reclining mechanism 30 side, and the second spiral spring 42 is disposed on the right side of the first spiral spring 41. That is, from the left side, the reclining mechanism 30, the first spiral spring 41, and the second spiral spring 42 are arranged in this order, and the second spiral spring 42 is located on the outermost side.

[0029] As shown in FIGS. 4, 8, and 9, the first spiral spring 41 is formed by winding a belt-shaped member having a predetermined width (length in the left-right direction) W1 in a spiral shape, and is attached to the right side surface 15b of the lower bracket 15 around an axis L2. Specifically, the first spiral spring 41 has a base end portion 411, a spiral portion 412, and a tip portion 413, and is configured by a spiral spring in which the base end portion 411 is not located on the spiral center (axis L2) and the number of turns of the spiral portion 412 is reduced. The base end portion 411 is fixed to the right side surface 15b by welding or the like so that the virtual spiral center of the first spiral spring 41 is located substantially at the same position as the axis L2 of the right side surface 15b of the lower bracket 15. The spiral portion 412 is configured by being wound a plurality of times radially outward (in the direction of arrow A in FIG. 8) from the base end portion 411. The tip portion 413 is bent and extends radially outward from the spiral portion 412, and is configured to be held in an engaged state with the holding portion 43.

[0030] The second spiral spring 42 is configured by winding a strip-shaped member having a predetermined width (length in the left-right direction) W2 in a spiral shape, similar to the first spiral spring 41, and is attached to the right side of the first spiral spring 41 around the axis L2. Specifically, the second spiral spring 42 has a base end portion 421, a spiral portion 422, and a tip end portion 423, and is constituted by a spiral spring in which the base end portion 421 is located at the spiral center. The base end portion 421 is fixed by welding or the like to an extending portion (not shown) formed to extend to the right around the axis L2 from the right side surface 15b. The spiral portion 422 is configured by being wound radially outward (in the direction of arrow A in FIG. 8) from the base end portion 421. The tip end portion 423 is bent and extends radially outward from the spiral portion 422, and is configured to be capable of being held in an engaged state with the holding portion 43.

[0031] In the present embodiment, the first spiral spring 41 is constituted by a spiral spring having a smaller biasing force than the second spiral spring 42. The biasing force of the spiral spring can be changed by changing the plate thickness, plate width, number of turns, etc., but the first spiral spring 41 is constituted by a spiral spring having a narrower plate width (W1 < W2) and a smaller number of turns than the second spiral spring 42. Further, the base end portion 411 of the first spiral spring 41 and the base end portion 421 of the second spiral spring 42 are fixed to different members by welding or the like.

[0032] The holding portion 43 is constituted by a substantially rectangular plate member having a predetermined width (length in the left-right direction) W3 (FIG. 4), a predetermined plate thickness, and a predetermined length (length in the direction of arrow in FIG. 8). The holding portion 43 is configured in a plate shape with a substantially central portion in the length direction bent outward, but may be configured in a substantially arc shape around the axis L2.

[0033] The holding portion 43 is fixed to the right side surface 25a by welding or the like in a state of protruding rightward substantially parallel to the axis L2 from the right side surface 25a of the upper bracket 25. Further, the holding portion 43 has a first concave portion 431 and a second concave portion 432 formed adjacent to the right side of the first concave portion 431 on the front end surface (tip portion) 43a in the direction of arrow A (rotation direction) in FIG. 8. The first concave portion 431 is provided at a position corresponding to the first spiral spring 41, and is formed in a concave shape over the width direction of the first spiral spring 41 so that the tip portion 413 of the first spiral spring 41 is held. The second concave portion 432 is provided at a position corresponding to the second spiral spring 42, and is formed in a concave shape over the width direction of the second spiral spring 42 so that the tip portion 423 of the second spiral spring 42 is held.

[0034] The width W4 of the first concave portion 431 is wider than the width W1 of the first spiral spring 41 (W4>W1), and the holding portion 43 holds the tip portion 413 in a state where the tip portion 413 of the first spiral spring 41 is engaged with the first concave portion 431. Similarly, the width W5 of the second concave portion 432 is wider than the width W2 of the tip portion 423 of the second spiral spring 42 (W5>W2), and the holding portion 43 holds the tip portion 423 in a state where the tip portion 423 of the second spiral spring 42 is engaged with the second concave portion 432. Thus, since the widths W4 and W5 of the first concave portion 431 and the second concave portion 432 are wider than the widths W1 and W2 of the first spiral spring 41 and the second spiral spring 42, respectively, the attachment of the respective tip portions 413 and 423 of the first spiral spring 41 and the second spiral spring 42 becomes easy.

[0035] The right end surface (end portion) 41a in the width direction (left - right direction) of the first spiral spring 41 is located inside (left side) in the width direction than the right end surface (end portion) 42a in the width direction (left - right direction) of the second spiral spring 42, and the right end surface 42a in the width direction of the second spiral spring is located inside (left side) in the width direction than the right end surface (tip portion) 43b in the width direction (left - right direction) of the holding portion 43.

[0036] The first concave portion 431 and the second concave portion 432 are provided at different positions in the rotational direction of the upper bracket 25 (the direction of arrow AB in FIG. 8) (FIG. 4). Specifically, the first concave portion 431 is provided on the B side of arrow in FIG. 8 than the second concave portion 432, and holds the tip portion 413 of the first spiral spring 41 on the B side of arrow in FIG. 8 than the second concave portion 432.

[0037] FIGS. 10A and 10B are diagrams schematically showing an example of the operation of the return mechanism 40 provided in the seat support device according to the present embodiment. In FIGS. 10A and 10B, unlike FIGS. 8 and 9, the first spiral spring 41 and the second spiral spring 42 are shown simultaneously. As shown in FIG. 10A, when the seat back 2 is in the reclined position, the reclining mechanism 30 is locked with the tip portion 413 of the first spiral spring 41 and the tip portion 423 of the second spiral spring 42 held by the holding portion 43. Therefore, the seat back 2 is held in the reclined position against the biasing forces of the first spiral spring 41 and the second spiral spring 42.

[0038] From this state, when the user operates the operation portions 9a and 9b to release the lock of the reclining mechanism 30, the seat back 2 rises by the biasing forces of the first spiral spring 41 and the second spiral spring 42, and when it rotates to the upright position, the reclining mechanism 30 is locked. Thereby, the seat back 2 is held in the upright position. If the seat back 2 stops before reaching the upright position, the user may manually push the seat back 2 backward to the upright position.

[0039] The seat support device configured as described above includes a first step of attaching the seat back 2 to the seat cushion 1 around the axis L2, a second step of attaching the reclining mechanism 30 to the side surface of the seat cushion 1, a third step of attaching the first spiral spring 41 around the axis L2 to the right of the reclining mechanism 30, and a fourth step of attaching the second spiral spring 42 around the axis L2 to the right of the first spiral spring 41. And it is manufactured by performing the second step after the first step, the third step after the second step, and finally the fourth step. By performing the fourth step last, it becomes easy to adjust the biasing force for returning the seat back 2 from the reclined state to the upright state.

[0040] According to the present embodiment, the following operational effects can be achieved. (1) The seat support device according to the present embodiment includes a seat cushion 1, a seat back 2, and a support portion SP that rotatably supports the seat back 2 around an axis L2 extending in a substantially horizontal direction within a predetermined rotation range including the upright position from the reclined position where the seat back 2 is reclined. The support portion SP includes a first spiral spring 41 and a second spiral spring 42 that bias the seat back 2 located at the reclined position in the upright direction, and a lock mechanism of the reclining mechanism 30 that holds the seat back 2 at the reclined position against the biasing forces of the first spiral spring 41 and the second spiral spring 42. The first spiral spring 41 and the second spiral spring 42 are configured such that their biasing forces are different from each other.

[0041] With this configuration, it becomes easy to adjust the biasing force that automatically returns the seat back 2 from the reclined state to the upright state. For example, if the biasing force of the biasing member (e.g., a spiral spring) is increased to increase the rotational speed at which the seat back 2 returns, the biasing force of the biasing member becomes a resistance when the user manually rotates the seat back 2 from the upright state to the reclined state. On the other hand, even if an appropriate biasing force is sought, it is difficult to adjust the spring force of the biasing member. In particular, in the case of a vehicle seat, since the self-weight of the seat back 2 also has an influence, the adjustment becomes even more difficult. Also, if the biasing member is to be made a dedicated product, development costs and the like increase. However, by using the first and second biasing members with different biasing forces as in the present embodiment, it becomes easy to control the rotational torque of the seat back 2 by the biasing member. For example, after attaching the first biasing member, by selecting and attaching an appropriate second biasing member according to the situation, the biasing force for automatically returning the seat back 2 can be adjusted.

[0042] (2) The first biasing member and the second biasing member have a width of a predetermined length substantially parallel to the axis L2, and are constituted by a first spiral spring 41 and a second spiral spring 42 wound radially outward. The support portion SP further includes a holding portion 43 that projects substantially parallel to the axis L2 from the seat back 2 and holds the tip portion 413 of the first spiral spring 41 and the tip portion 423 of the second spiral spring 42, respectively. The holding portion 43 has a first concave portion 431 formed in a concave shape over the width direction of the first spiral spring 41 so that the tip portion 413 of the first spiral spring 41 is held, and a second concave portion 432 formed in a concave shape over the width direction of the second spiral spring 42 so that the tip portion 423 of the second spiral spring 42 is held. The first concave portion 431 and the second concave portion 432 are provided at different positions in the rotational direction of the seat back 2.

[0043] With this configuration, since the tip portions 413 of the first spiral spring 41 and the tip portions 423 of the second spiral spring 42 are held only by the holding portion 43, an increase in the number of parts can be suppressed. Further, since the first concave portion 431 and the second concave portion 432 are provided, it becomes difficult for the tip portions 413 of the first spiral spring 41 and the tip portions 423 of the second spiral spring 42 to fall off from the holding portion 43. Furthermore, since the first concave portion 431 and the second concave portion 432 are provided, interference between the first spiral spring 41 and the second spiral spring 42 can be prevented, and generation of abnormal noise and torque cross caused by mutual interference can be prevented.

[0044] (3) The first biasing member and the second biasing member have a width of a predetermined length substantially parallel to the axis L2, and are constituted by a first spiral spring 41 and a second spiral spring 42 wound radially outward. The base end portion 411 of the first spiral spring 41 and the base end portion 421 of the second spiral spring 42 can be attached to different members from each other. With this configuration, enlargement of the members to which the base end portion 411 of the first spiral spring 41 and the base end portion 421 of the second spiral spring 42 are attached, complication of the structure, etc. can be suppressed.

[0045] (4) The first biasing member and the second biasing member have a width of a predetermined length substantially parallel to the axis L2, and are constituted by a first spiral spring 41 and a second spiral spring 42 wound radially outward. The support portion SP projects from the seat back 2 substantially parallel to the axis L2, and further includes a holding portion 43 that holds the tip portion 413 of the first spiral spring 41 and the tip portion 423 of the second spiral spring 42, respectively. The right end surface 41a of the first spiral spring 41 and the right end surface 42a of the second spiral spring 42 are located inside (left side) of the right end surface (tip portion) 43b of the holding portion 43. With this configuration, the first spiral spring 41 and the second spiral spring 42 can be arranged compactly in the left - right direction.

[0046] (5) The first spiral spring 41 and the second spiral spring 42 are arranged on the right side (outer side) in the left - right direction (substantially horizontal direction) rather than the lock mechanism of the reclining mechanism 30. With this configuration, workability and maintainability when assembling the first spiral spring 41 and the second spiral spring 42 to the right lower bracket 15 can be improved.

[0047] (6) A seat support device manufacturing method, comprising a seat cushion 1, a seat back 2, and a support portion SP that rotatably supports the seat back 2 about an axis L2 extending in a substantially horizontal direction within a predetermined rotation range including the upright position from the reclined position where the seat back 2 is reclined. The support portion SP has a first spiral spring 41 and a second spiral spring 42 that urge the seat back 2 in the upright direction with different biasing forces when the seat back 2 is in the reclined position, and a locking mechanism of a reclining mechanism 30 that holds the seat back 2 in the reclined position against the biasing forces of the first spiral spring 41 and the second spiral spring 42. This manufacturing method includes a first step of attaching the seat back 2 rotatably about the axis L2 to the seat cushion 1, a second step of attaching the locking mechanism of the reclining mechanism 30 to the side surface of the seat cushion 1, a third step of attaching the first spiral spring 41 about the axis L2, and a fourth step of further attaching the second spiral spring 42 about the axis L2. With this configuration, it becomes easy to adjust the biasing force for automatically returning the seat back 2 from the reclined state to the upright state.

[0048] The above embodiment can be modified in various forms. Hereinafter, modification examples will be described.

[0049] In the above embodiment, the first spiral spring 41 is attached to the right side surface 15b of the right lower bracket (first frame) 15, and further, the second spiral spring 42 is attached to the right side of the first spiral spring 41. However, a configuration may be adopted in which the first spiral spring 41 is attached to the right side surface 15b of the right lower bracket 15, and the second spiral spring 42 is attached to the left side surface of the left lower bracket (second frame) 15. With this configuration, it is possible to avoid the concentration of components such as the first spiral spring 41 and the second spiral spring 42 on the right side (one side) lower bracket 15. In addition, it is possible to suppress the enlargement of the resin cover for covering the component unit when the first spiral spring 41 and the second spiral spring 42 are assembled.

[0050] In the above embodiment, the first spiral spring 41 is attached to the right side surface 15b of the right lower bracket (first frame) 15, and the second spiral spring 42 is further attached to the right side of the first spiral spring 41. However, at least one of the first spiral spring 41 and the second spiral spring 42 may be attached to the right side surface 15b of the right lower bracket 15, and a rotary damper (damping device) may be attached to the left side surface of the left lower bracket (second frame) 15. The rotary damper is configured to exert a damping force acting in a direction opposite to the biasing direction in which the first spiral spring 41 and the second spiral spring 42 bias the seat back 2, starting from a position in front of (during the standing up) the standing position of the seat back 2. Since a well-known rotary damper can be used, a specific description thereof is omitted here.

[0051] With this configuration, after the lock at the reclined position is released and before the seat back 2 reaches the standing position, the biasing forces of the first spiral spring 41 and the second spiral spring 42 can be suppressed, and the rotation speed of the seat back 2 can be reduced. Also, by separately arranging the first spiral spring 41 and the second spiral spring 42 and the rotary damper on the left and right lower brackets 15, it is possible to avoid the concentration of components on one side (for example, the right side) of the lower bracket 15. And it is possible to suppress the enlargement of the resin cover for covering the component unit when assembling components such as the first spiral spring 41 and the second spiral spring 42 and the rotary damper.

[0052] In the above embodiment, the first spiral spring 41 and the second spiral spring 42 are used as the first biasing member and the second biasing member, but a configuration using a biasing member other than a spiral spring may also be used. For example, a configuration using a torsion spring may be used, and the first biasing member and the second biasing member may be the first torsion spring and the second torsion spring.

[0053] In the above-described embodiment, the first spiral spring 41 is configured by a spiral spring having a smaller biasing force than the second spiral spring 42. However, the first spiral spring 41 may be configured by a spiral spring having a larger biasing force than the second spiral spring 42. That is, the first spiral spring 41 and the second spiral spring 42 may be spiral springs having different biasing forces.

[0054] In the above-described embodiment, the first recess 431 is provided on the arrow B side in FIG. 8 rather than the second recess 432. However, the second recess 432 may be provided on the arrow B side in FIG. 8 rather than the first recess 431. That is, the first recess 431 and the second recess 432 may be provided at different positions in the direction of the arrow in FIG. 8.

[0055] The above description is merely an example, and the present invention is not limited to the above-described embodiment and modified example as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above-described embodiment and modified example, and it is also possible to combine the modified examples with each other.

Description of Reference Numerals

[0056] 1 Seat cushion, 2 Seat back, 30 Reclining mechanism, 41 First spiral spring (first biasing member), 42 Second spiral spring (second biasing member), 43 Holding portion, 411 Base end portion, 413 Tip end portion, 421 Base end portion, 423 Tip end portion, 431 First recess, 432 Second recess, L2 Axis, SP Support portion

Claims

1. A seat cushion, a seat back connected to the rear end of the seat cushion, and a support portion disposed below a connection point between the seat cushion and the seat back, the support portion rotatably supporting the seat back about an axis extending in a substantially horizontal direction within a predetermined rotation range including a standing position from a reclined position where the seat back is reclined. The seat support device includes: the support portion having a biasing member that biases the seat back in an upright direction when the seat back is in the reclined position, and a locking mechanism that holds the seat back in the reclined position against the biasing force of the biasing member; the biasing member being constituted by a first biasing member and a second biasing member that bias the seat back in the upright direction with different biasing forces; the first biasing member and the second biasing member having a width of a predetermined length substantially parallel to the axis, and being constituted by spiral springs wound radially outward; the support portion further including a holding portion that projects substantially parallel to the axis from the seat back and holds a radially outer end portion of the first biasing member and a radially outer end portion of the second biasing member, respectively; the holding portion having a first concave portion formed in a concave shape across a width direction of the first biasing member so that the radially outer end portion of the first biasing member is held, and a second concave portion formed in a concave shape across a width direction of the second biasing member so that the radially outer end portion of the second biasing member is held; the seat support device, wherein the first concave portion and the second concave portion are provided at different positions in a rotation direction of the seat back.

2. In the seat support device according to claim 1, an inner end portion in a radial direction of the first biasing member and an inner end portion in a radial direction of the second biasing member are attached to different members. The seat support device is characterized by this.

3. In the seat support device according to claim 1, end portions in a width direction of the first biasing member and end portions in a width direction of the second biasing member are located inside a tip portion in the substantially horizontal direction of the holding portion. The seat support device is characterized by this.

4. In the seat support device according to any one of claims 1 to 3, the first biasing member and the second biasing member are disposed outside the locking mechanism in the substantially horizontal direction. The seat support device is characterized by this.

5. In the seat support device according to claim 1 or 2, The seat back has a first frame located on one side in the substantially horizontal direction and a second frame located on the other side. The locking mechanism and the first biasing member are arranged on the first frame, and the second biasing member is arranged on the second frame, which is a characteristic of the seat support device. **Claim 6**: In the seat support device according to any one of claims 1 to 4, The seat support device further includes a damping device that exerts a damping force acting in a direction opposite to the biasing direction in which the first biasing member and the second biasing member bias the seat back, from the upright position of the seat back. The seat back has a first frame located on one side in the substantially horizontal direction and a second frame located on the other side. At least one of the first biasing member and the second biasing member is arranged on the first frame, and the damping device is arranged on the second frame, which is a characteristic of the seat support device. **Claim 7**: A seat cushion, a seat back connected to the rear end of the seat cushion, and a support portion disposed below the connection point between the seat cushion and the seat back, and rotatably supporting the seat back about an axis extending substantially horizontally within a predetermined rotation range including the upright position from the reclined position where the seat back is reclined. The support portion includes a first biasing member and a second biasing member that bias the seat back in the upright direction with different biasing forces when the seat back is in the reclined position, a locking mechanism that holds the seat back in the reclined position against the biasing forces of the first biasing member and the second biasing member, and a holding portion that projects from the seat back substantially parallel to the axis and holds the radially outer ends of the first biasing member and the second biasing member respectively. The holding portion has a first concave portion formed in a concave shape across the width direction of the first biasing member so that the radially outer end of the first biasing member is held, and a second concave portion formed in a concave shape across the width direction of the second biasing member so that the radially outer end of the second biasing member is held. A manufacturing method of the seat support device, A step of rotatably attaching the seat back to the seat cushion about the axis. A step of attaching the locking mechanism to the side surface of the seat cushion. A step of attaching the spiral first biasing member to the first concave portion about the axis. Furthermore, a step of attaching the spiral second biasing member to the second recess around the axis, and a method for manufacturing a seat support device characterized by including the step. **Claim 8**: A vehicle seat characterized by mounting the seat support device according to any one of Claims 1 to 6.

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