JP7701595B2 - SEAT SUPPORT DEVICE, MANUFACTURING METHOD FOR SEAT SUPPORT DEVICE, AND VEHICLE SEAT - Google Patents

Description

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

Conventionally, there is known a device that rotatably supports a seat back with respect to a seat cushion via a spiral spring (see, for example, Patent Document 1). The device described in Patent Document 1 has a spiral spring with one end and the other end engaged with the seat cushion side and the seat back side, respectively, and is configured so that the seat back, which is locked in a forward-tilted state against the biasing force of the spiral spring, automatically stands up due to the biasing force of the spiral spring when the lock is released.

Japanese Unexamined Patent Publication No. 8-19444

However, in a device such as that described in Patent Document 1, which automatically raises a seat back that has been tilted forward against the biasing force of a biasing member (spiral spring), it is difficult to adjust the biasing force of the biasing member.

A seat support device according to one aspect of the present invention includes a seat cushion, a seat back connected to a rear end of the seat cushion, and a support portion disposed below a connection point between the seat cushion and the seat back and supporting the seat back rotatably about an axis extending in a substantially horizontal direction within a predetermined rotation range including a reclined position where the seat back is reclined and an upright position. The support portion has a biasing member that biases the seat back in the 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 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 and second biasing members are constituted by spiral springs having a predetermined width substantially parallel to the axis and wound radially outward, and the support portion further includes a holding portion protruding substantially parallel to the axis from the seat back and holding a radially outer end of the first biasing member and a radially outer end of the second biasing member, respectively. The holding portion has a first recess formed in a concave shape across the width of the first biasing member so as to hold the radially outer end of the first biasing member, and a second recess formed in a concave shape across the width of the second biasing member so as to hold the radially outer end of the second biasing member, and the first recess and the second recess are provided at different positions in the rotation direction of the seat back.

Another aspect of the present invention is a seat cushion, a seat back connected to a rear end of the seat cushion, and a support portion disposed below a connection point between the seat cushion and the seat back, and supporting the seat back rotatably about an axis extending in a substantially horizontal direction within a predetermined rotation range including a reclined position where the seat back is reclined and an upright position, the support portion being provided with a first biasing member and a second biasing member that bias the seat back in the reclined position in an upright direction with mutually different biasing forces, and A method for manufacturing a seat support device including a lock mechanism that holds a seat back in a reclined position against a biasing force, and a holding portion that protrudes from the seat back substantially parallel to an axis and holds a radially outer end of a first biasing member and a radially outer end of a second biasing member, the holding portion having a first recess that is formed in a concave shape across the width of the first biasing member so as to hold the radially outer end of the first biasing member, and a second recess that is formed in a concave shape across the width of the second biasing member so as to hold the radially outer end of the second biasing member. The method for manufacturing the seat support device includes the steps of attaching a seat back to a seat cushion so as to be rotatable around an axis, attaching a lock mechanism to a side of the seat cushion, attaching a first biasing member that is spiral-shaped around the axis to the first recess , and further attaching a second biasing member that is spiral-shaped around the axis to the second recess .

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.

1 is a side view showing a schematic configuration of a vehicle seat to which a seat support device according to an embodiment of the present invention is applied; FIG. 2 is a perspective view of a seat frame that constitutes the framework of the seat in FIG. 1 . 2 is a side view showing an example of a rotation operation of the vehicle seat of FIG. 1; FIG. FIG. 3B is a side view showing an example of an operation subsequent to FIG. 3A . FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2 . 5 is a cross-sectional view taken along line VV in FIG. 4 . FIG. 3 is a perspective view of the seat frame of FIG. 2 as viewed obliquely from behind. FIG. 6 is a plan view showing a main configuration of the reclining mechanism of FIG. 5 . 4 is a perspective view of a main configuration of a return mechanism provided in the seat support device according to the embodiment, as viewed obliquely from the front. FIG. FIG. 4 is a perspective view of the main components of the return mechanism when positioned in the inverted position, as viewed obliquely from behind. 5A to 5C are diagrams illustrating an example of an operation of a return mechanism provided in the seat support device according to the embodiment of the present invention. FIG. 10B is a diagram showing an example of the operation following FIG. 10A .

Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 10B. The seat support device according to the embodiment of the present invention is applied to a vehicle seat, for example a vehicle seat, in particular a rear seat facing a back door provided on the rear side of the vehicle. The seat support device can also be applied to a front seat of a vehicle, and can also be applied to other vehicle seats. It can also be applied to things other than vehicle seats.

Figure 1 is a side view showing the 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 this embodiment is applied. As shown in Figure 1, the seat 100 has 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. In the following, the front-rear direction, left-right direction, and 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 these definitions.

A pair of left and right lower rails 5 extending in the front-rear direction are fixed to the upper surface of the vehicle floor 4. A pair of left and right upper rails 6 extending in the front-rear direction are provided above the lower rails 5. The upper rails 6 are capable of sliding in the front-rear direction on the lower rails 5, and the lower rails 5 and the upper rails 6 form a slide mechanism 7.

The seat 100 has a seat frame 101 that forms the framework of the seat 100. FIG. 2 is a perspective view of the seat frame 101 that forms the framework of the seat 100, and shows the state in which the cover and pads of the seat 100 have been removed from FIG. 1. As shown in FIG. 2, the seat frame 101 has a seat cushion frame 10 that forms the framework of the seat cushion 1, and a seat back frame 20 that forms the framework of the seat back 2. The seat cushion frame 10 has a pair of left and right lower frames 11 that extend in the front-rear direction, and a pair of front and rear connecting frames 12, 13 that extend in the left-right direction and connect the left and right lower frames 11 to each other, and is configured as a frame in a plan view as a whole. The front ends of the left and right lower frames 11 are supported by a pair of left and right leg frames 14 that are erected on the upper rail 6. The upper and lower ends of the leg frames 14 are rotatably supported by the lower frame 11 and the upper rail 6, respectively, with the pivot shafts extending in the left-right direction as fulcrums.

The seatback frame 20 has a frame 20a that is generally rectangular in shape when viewed from the front and is composed of a pair of left and right side frames 21 that extend in the vertical direction, a pair of upper and lower connecting frames 22, 23 that extend in the horizontal direction and connect the left and right side frames 21, and a generally rectangular plate-like back panel 24 fixed to the rear surface of the frame 20a. A generally plate-like upper bracket 25 is fixed to the lower end of each of the left and right side frames 21. The upper bracket 25 extends below the connecting frame 23, is formed wide in the front-rear direction, and has a pair of left and right side surfaces 25a that face outward in the horizontal direction.

The left and right lower frames 11 of the seat cushion frame 10 are disposed on the left and right outer sides of the left and right upper brackets 25 with a gap in the left and right direction from the side surfaces 25a of the upper brackets 25. The rear end of the lower frame 11 is rotatably supported on the lower end of the upper bracket 25 with a pivot shaft 26 extending along the left and right axis L1 as a fulcrum. The left and right lower frames 11 are positioned at approximately the same position in the left and right direction as the left and right upper rails 6. A pair of left and right lower brackets 15, which are approximately plate-shaped and protrude upward from the rear ends of the left and right upper rails 6. The left and right lower brackets 15 are connected together by a connecting frame 16 extending in the left and right direction.

The seatback frame 20 is supported by the lower bracket 15 so as to be rotatable about an axis L2 extending in the left-right direction. That is, a support part SP is provided at the upper end of the lower bracket 15, and the upper bracket 25 is rotatably supported by the support part SP. As shown in FIG. 1, the angle (inclination angle θ) of the seatback 2 with respect to the horizontal line is changed via the support part SP.

3A and 3B are diagrams showing an example of the rotational movement of the seat back 2. In particular, FIG. 3B shows the state in which the seat back 2 has been rotated forward to the maximum, and FIG. 3A shows the state in which the seat back 2 is in the middle of being rotated. The position of the seat back 2 in FIG. 1 is called the standing position, and the position of the seat back 2 in FIG. 3B is called the reclining position (storage position). In the standing position, the inclination angle θ is about 90 degrees (strictly speaking, about 100 to 110 degrees), and in the reclining position, the inclination angle θ is about 0 degrees. The seat back 2 can be rotated forward around the axis L2 from the standing position to the reclining position. Specifically, as shown in FIG. 3A, the leg frame 14 is folded in the direction of the arrow A during the rotation of the seat back 2, and the seat cushion 1 moves in the direction of the arrow B (forward) accordingly, so that the seat back 2 can be rotated to the reclining position shown in FIG. 3B.

Figure 4 is a plan view (a cross-sectional view taken along line IV-IV in Figure 2) that shows a schematic view of the support part SP in Figure 2 as seen from above. As shown in Figure 4, the support part SP has a reclining mechanism 30 that tilts the seat back 2 (upper bracket 25) to lock it in the reclined position and the upright position, and a return mechanism 40 that returns the seat back 2, which has been unlocked 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, centered on the axis L2. The return mechanism 40 is provided on the right side surface 15b of the right lower bracket 15, centered on the axis L2.

Figure 5 is a front view (sectional view taken along line V-V in Figure 4) showing the schematic configuration of the reclining mechanism 30 having a locking mechanism. As shown in Figure 5, the reclining mechanism 30 has 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 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 locking members 35 disposed in the internal space, and a pair of left and right torsion springs 36 that bias the cam plate 34 in the direction of the arrow A.

The locking member 35 engages with a guide groove 31a formed on the left surface of the lower plate 31 and is configured to be movable up and down along the guide groove 31a, i.e., radially inward and radially outward. The locking 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 circumferentially on the inner peripheral surface that forms the internal space. When the external teeth 35a of the locking member 35 move radially outward, they engage with the internal teeth 32a of the upper plate 32. The cam plate 34 engages with the locking member 35, and when the cam plate 34 is rotated in the direction of arrow A by the biasing force of the torsion spring 36 as shown in the figure, the locking member 35 moves radially outward. As a result, the external teeth 35a mesh with the internal teeth 32a, and the rotational position of the upper bracket 25 relative to the lower bracket 15 is fixed (reclining lock).

On the other hand, when the cam plate 34 is rotated in the direction of arrow B against the biasing force of the torsion spring 36, the locking member 35 is moved radially inward. This causes the outer teeth 35a to move away from the inner teeth 32a, allowing the upper bracket 25 to rotate relative to the lower bracket 15 (reclining lock released). The connecting shaft 33 passes through the upper bracket 25, and a release lever 37 is joined to its left end. The operating strap is engaged with the release lever 37 via a link mechanism.

Figure 6 is a perspective view showing the configuration of the operating strap, that is, a perspective view of the seat frame 101 as seen obliquely from the rear. As shown in Figure 6, the front ends of a pair of left and right connection frames 17 extending in the front-rear direction are fixed by welding or the like to the connecting frame 16 extending between the left and right lower brackets 15. A connection pipe 18 extending in the left-right direction is fixed by welding or the like to the rear ends of the left and right connection frames 17. A tether anchor 19 for fixing a child seat is fixed by welding or the like to the approximately center of the left-right direction of the connection pipe 18. A pair of left and right strap support wires 191, 192 formed in an approximately U-shape facing rearward are joined to the lower ends of the connection pipes. A wire pipe 193 extending in the left-right direction is joined to the bottom surfaces of the strap support wires 191, 192.

A pair of left and right operating straps 8, 9 are inserted between the strap support wires 191, 192 and the wire pipe 193. One of the operating straps 8, 9 (e.g., operating strap 8) is an operating strap for unlocking the slide mechanism 7 (FIG. 1), and the other (e.g., operating strap 9) is an operating strap for unlocking the reclining mechanism 30. The operating straps 8, 9 extend in the front-rear direction below the seat cushion frame 10, and at their rear ends, operating parts 8a, 9a that are held by the user are provided facing upward. Link mechanisms (not shown) are connected to the front ends of the operating straps 8, 9. The link mechanisms are constantly biased by springs that lock the slide mechanism 7 and the reclining mechanism 30, and the operating straps 8, 9 are biased forward (the operating parts 8a, 9a are biased downward).

When the user pulls the operating part 8a of the operating strap 8 upward against the spring force, for example with the back door open, the slide mechanism 7 is unlocked via the link mechanism. This allows the upper rail 6 to slide on the lower rail 5. When the user pulls the operating part 9a of the operating strap 9 upward against the spring force, the connecting shaft 33 is rotated in the direction of arrow B in FIG. 5 via the link mechanism. This unlocks the reclining mechanism 30 and allows the seat back 2 (upper bracket 25) to rotate.

Although not shown, a release cable is connected to the link mechanism connected to the operating strap 9. As shown in FIG. 2, the release cable 90 extends vertically along the space to the right of the right side frame 21, and its upper end is connected to an operating part 9b (see FIG. 1) protruding from the upper end of the seatback frame 20. When the operating 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. This allows the user to unlock the reclining mechanism 30 not only by pulling up the operating part 9a but also by pulling up the operating part 9b. For example, a user standing to the right of the seat 100 can unlock the reclining mechanism 30 by operating the operating part 9b.

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

When the reclining mechanism 30 is unlocked from this state by operating the operating parts 9a and 9b and the upper plate 32 is rotated in the direction of the arrow B in FIG. 7, the cam pin 35b engages with the second inner peripheral surface 32b2. This causes the locking member 35 to move radially inward, the outer teeth 35a to move away from the inner teeth 32a, and the reclining mechanism 30 is unlocked. In this case, even if the operation of the operating parts 9a and 9b is stopped, the outer teeth 35a remain separated from the inner teeth 32a, and the unlocked state is maintained. When the seat back 2 rotates to the reclining position, the cam pin 35b engages with the circumferential end (position P0) of the first inner peripheral surface 32b1. This causes the locking member 35 to move radially outward due to the biasing force of the torsion spring 36 (FIG. 5), and the outer teeth 35a mesh with the inner teeth 32a, locking the seat back 2 in the reclining position.

When the reclining mechanism 30 is unlocked by operating the operating parts 9a and 9b while the seat back 2 is in the reclined position, the seat back 2 is rotated in the direction of arrow A in FIG. 7 by the return mechanism 40 and locked in the upright position.

Figure 8 is a perspective view of the main components of the return mechanism 40 as viewed diagonally from the front (upright position), and Figure 9 is a perspective view as viewed diagonally from the rear (tilted position). As shown in Figures 8 and 9, the return mechanism 40 has a first spiral spring 41 and a second spiral spring 42 that have different biasing forces, and a holding portion 43 that holds the tip end of the first spiral spring 41 and the tip end 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 to the right 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 disposed in this order, with the second spiral spring 42 located at the outermost position.

4, 8 and 9, the first spiral spring 41 is formed by winding a band-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 the axis L2. Specifically, the first spiral spring 41 has a base end 411, a spiral portion 412, and a tip end 413, and is formed by a spiral spring in which the base end 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 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 at approximately the same position as the axis L2 of the right side surface 15b of the lower bracket 15. The spiral portion 412 is formed by winding it multiple times radially outward from the base end 411 (in the direction of the arrow A in FIG. 8). 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 by the holding portion 43.

The second spiral spring 42, like the first spiral spring 41, is formed by winding a band-shaped member having a predetermined width (length in the left-right direction) W2 into a spiral shape, 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 421, a spiral portion 422, and a tip end 423, and is formed by a spiral spring in which the base end 421 is located at the center of the spiral. The base end 421 is fixed by welding or the like to an extension portion (not shown) formed by extending from the right side surface 15b to the right side around the axis L2. The spiral portion 422 is formed by winding from the base end 421 radially outward (in the direction of the arrow A in FIG. 8). The tip end 423 is configured to be bent and extended radially outward from the spiral portion 422, and can be held in a state engaged with the holding portion 43.

In this embodiment, the first spiral spring 41 is composed of a spiral spring with 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 composed of a spiral spring with a narrower plate width (W1 < W2) and fewer turns than the second spiral spring 42. In addition, the base end 411 of the first spiral spring 41 and the base end 421 of the second spiral spring 42 are fixed to different members by welding or the like.

The holding portion 43 is made of 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 the arrow in FIG. 8). The holding portion 43 is made in a plate shape with the approximate center in the length direction bent outward, but it may also be made in a substantially arc shape centered on the axis L2.

The holding portion 43 is fixed to the right side surface 25a by welding or the like in a state where it protrudes from the right side surface 25a of the upper bracket 25 to the right side in a direction substantially parallel to the axis L2. The holding portion 43 also has a first recess 431 and a second recess 432 formed adjacent to the right side of the first recess 431 on the tip surface (tip portion) 43a in the direction of the arrow A (rotation direction) in FIG. 8. The first recess 431 is provided at a position corresponding to the first spiral spring 41 and is formed in a concave shape in 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 recess 432 is provided at a position corresponding to the second spiral spring 42 and is formed in a concave shape in the width direction of the second spiral spring 42 so that the tip portion 423 of the second spiral spring 42 is held.

The width W4 of the first recess 431 is wider than the width W1 of the first spiral spring 41 (W4>W1), and the retaining portion 43 holds the tip 413 of the first spiral spring 41 in a state where the tip 413 is engaged with the first recess 431. Similarly, the width W5 of the second recess 432 is wider than the width W2 of the tip 423 of the second spiral spring 42 (W5>W2), and the retaining portion 43 holds the tip 423 of the second spiral spring 42 in a state where the tip 423 of the second spiral spring 42 is engaged with the second recess 432. In this way, the widths W4 and W5 of the first recess 431 and the second recess 432 are wider than the widths W1 and W2 of the first spiral spring 41 and the second spiral spring 42, so that the respective tip portions 413 and 423 of the first spiral spring 41 and the second spiral spring 42 can be easily assembled.

The right end face (end) 41a in the width direction (left-right direction) of the first spiral spring 41 is located inward (left side) in the width direction than the right end face (end) 42a in the width direction (left-right direction) of the second spiral spring 42, and the right end face 42a in the width direction of the second spiral spring is located inward (left side) in the width direction than the right end face (tip) 43b in the width direction (left-right direction) of the retaining portion 43.

The first recess 431 and the second recess 432 are provided at different positions in the rotation direction of the upper bracket 25 (the direction of the arrows AB in FIG. 8) (FIG. 4). Specifically, the first recess 431 is provided on the side of the arrow B in FIG. 8 from the second recess 432, and holds the tip 413 of the first spiral spring 41 on the side of the arrow B in FIG. 8 from the second recess 432.

10A and 10B are diagrams showing an example of the operation of the return mechanism 40 provided in the seat support device according to this embodiment. Unlike FIGS. 8 and 9, FIGS. 10A and 10B show the first spiral spring 41 and the second spiral spring 42 at the same time. As shown in FIG. 10A, when the seat back 2 is in the reclining position, the reclining mechanism 30 is locked with the tip 413 of the first spiral spring 41 and the tip 423 of the second spiral spring 42 held by the holding portion 43. Therefore, the seat back 2 is held in the reclining position against the biasing forces of the first spiral spring 41 and the second spiral spring 42.

When the user operates the operating parts 9a and 9b to unlock the reclining mechanism 30 from this state, the seat back 2 rises due to the biasing force 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. This holds the seat back 2 in the upright position. If the seat back 2 stops before reaching the upright position, the user can manually push the seat back 2 backward to the upright position.

The seat support device thus configured 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 of the seat cushion 1, a third step of attaching the first spiral spring 41 to the right of the reclining mechanism 30 around the axis L2, and a fourth step of attaching the second spiral spring 42 to the right of the first spiral spring 41 around the axis L2. The seat support device is manufactured by carrying out the second step after the first step, the third step after the second step, and finally the fourth step. By carrying out the fourth step last, it becomes easy to adjust the biasing force that returns the seat back 2 from the reclined state to the upright state.

According to this embodiment, the following advantageous effects can be obtained.
(1) The seat support device according to this embodiment includes a seat cushion 1, a seat back 2, and a support part SP that supports the seat back 2 rotatably about an axis L2 extending in a substantially horizontal direction within a predetermined rotation range including a reclined position where the seat back 2 is reclined and an upright position. The support part SP has a first spiral spring 41 and a second spiral spring 42 that bias the seat back 2 in the upright direction when the seat back 2 is in the reclined position, and a locking mechanism of the 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. The first spiral spring 41 and the second spiral spring 42 are configured to have mutually different biasing forces.

This configuration makes it easy to adjust the biasing force that automatically returns the seat back 2 from a reclined state to an upright state. For example, if the biasing force of the biasing member (e.g., a spiral spring) is increased to increase the rotation speed at which the seat back 2 is returned, 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 to be obtained, it is difficult to adjust the spring force of the biasing member. In particular, in the case of a vehicle seat, the weight of the seat back 2 also has an effect, making adjustment even more difficult. In addition, if the biasing member is made into a dedicated product, development costs and the like increase. However, as in this embodiment, by using first and second biasing members with different biasing forces, it becomes easy to control the rotation torque of the seat back 2 by the biasing member. For example, after installing the first biasing member, the biasing force that automatically returns the seat back 2 can be adjusted by selecting and installing an appropriate second biasing member according to the situation.

(2) The first and second urging members are composed of a first spiral spring 41 and a second spiral spring 42 that have a width of a predetermined length substantially parallel to the axis L2 and are wound radially outward. The support portion SP is further provided with a holding portion 43 that protrudes 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 recess 431 that is formed in a concave shape across the width direction of the first spiral spring 41 so as to hold the tip portion 413 of the first spiral spring 41, and a second recess 432 that is formed in a concave shape across the width direction of the second spiral spring 42 so as to hold the tip portion 423 of the second spiral spring 42. The first recess 431 and the second recess 432 are provided at different positions in the rotation direction of the seat back 2.

With this configuration, the tip 413 of the first spiral spring 41 and the tip 423 of the second spiral spring 42 are held only by the holding portion 43, so that the number of parts can be suppressed from increasing. In addition, since the first recess 431 and the second recess 432 are provided, the tip 413 of the first spiral spring 41 and the tip 423 of the second spiral spring 42 are less likely to fall off the holding portion 43. Furthermore, since the first recess 431 and the second recess 432 are provided, interference between the first spiral spring 41 and the second spiral spring 42 can be prevented, and abnormal noise and torque loss caused by mutual interference can be prevented.

(3) The first and second urging members are composed of a first spiral spring 41 and a second spiral spring 42 that have a width of a predetermined length approximately parallel to the axis L2 and are wound radially outward, and the base end 411 of the first spiral spring 41 and the base end 421 of the second spiral spring 42 are attached to different members. This configuration makes it possible to prevent the members that attach the base end 411 of the first spiral spring 41 and the base end 421 of the second spiral spring 42 from becoming larger or more complex in structure.

(4) The first and second urging members are composed of a first spiral spring 41 and a second spiral spring 42 that have a width of a predetermined length substantially parallel to the axis L2 and are wound radially outward. The support portion SP is further provided with a holding portion 43 that protrudes 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 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 (to the left) of the right end surface (tip portion) 43b of the holding portion 43. This configuration allows the first spiral spring 41 and the second spiral spring 42 to be arranged compactly in the left-right direction.

(5) The first spiral spring 41 and the second spiral spring 42 are positioned to the right (outside) of the locking mechanism of the reclining mechanism 30 in the left-right direction (approximately horizontal direction). This configuration improves workability and maintainability when assembling the first spiral spring 41 and the second spiral spring 42 to the right lower bracket 15.

(6) A method for manufacturing a seat support device comprising a seat cushion 1, a seat back 2, and a support part SP that supports the seat back 2 to be rotatable about an axis L2 extending substantially horizontally within a predetermined rotation range including a reclined position in which the seat back 2 is reclined to an upright position, wherein the support part SP has a first spiral spring 41 and a second spiral spring 42 that urge the seat back 2 in the reclined position in the upright direction with different urging forces, and a locking mechanism for a reclining mechanism 30 that holds the seat back 2 in the reclined position against the urging 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 to the seat cushion 1 so that the seat back 2 can rotate around the axis L2, a second step of attaching the lock mechanism of the reclining mechanism 30 to the side of the seat cushion 1, a third step of attaching the first spiral spring 41 around the axis L2, and a fourth step of attaching the second spiral spring 42 around the axis L2. This configuration makes it easy to adjust the biasing force that automatically returns the seat back 2 from a reclined state to an upright state.

The above embodiment can be modified in various ways. Modifications are described below.

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 attached to the right side of the first spiral spring 41. However, the first spiral spring 41 may be attached to the right side surface 15b of the right lower bracket 15, and the second spiral spring 42 may be attached to the left side surface of the left lower bracket (second frame) 15. This configuration makes it possible to avoid consolidating parts such as the first spiral spring 41 and the second spiral spring 42 in the right (one) lower bracket 15. It also makes it possible to prevent the size of the resin cover for covering the parts unit when the first spiral spring 41 and the second spiral spring 42 are assembled.

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 attached to the right side of the first spiral spring 41. Alternatively, 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 the opposite direction to the biasing direction of the first spiral spring 41 and the second spiral spring 42 biasing the seat back 2 from just before the seat back 2 is raised (midway up). A well-known rotary damper can be used, so a detailed description will be omitted here.

With this configuration, after the lock in the reclined position is released, the biasing force of the first spiral spring 41 and the second spiral spring 42 can be suppressed before the seat back 2 is positioned in the upright position, and the rotation speed of the seat back 2 can be reduced. In addition, since the first spiral spring 41, the second spiral spring 42, and the rotary damper are arranged separately on the left and right lower brackets 15, it is possible to avoid concentrating parts on the lower bracket 15 on one side (for example, the right side). In addition, it is possible to prevent the resin cover for covering the parts unit and the rotary damper from becoming large when parts such as the first spiral spring 41 and the second spiral spring 42 are assembled.

In the above embodiment, the first and second spiral springs 41 and 42 are used as the first and second biasing members, but biasing members other than spiral springs may be used. For example, a torsion spring may be used, and the first and second biasing members may be the first and second torsion springs.

In the above embodiment, the first spiral spring 41 is configured with a spiral spring having a smaller biasing force than the second spiral spring 42, but the first spiral spring 41 may be configured with a spiral spring having a larger biasing force than the second spiral spring 42. In other words, the first spiral spring 41 and the second spiral spring 42 may be spiral springs having different biasing forces.

In the above embodiment, the first recess 431 is provided on the side of the arrow B in FIG. 8 relative to the second recess 432, but the second recess 432 may be provided on the side of the arrow B in FIG. 8 relative to the first recess 431. In other words, it is sufficient that the first recess 431 and the second recess 432 are provided at different positions in the direction of the arrow in FIG. 8.

The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the characteristics of the present invention are not impaired. It is also possible to combine one or more of the above-mentioned embodiment and modifications in any desired manner, and it is also possible to combine modifications together.

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 portion, 421 base end portion, 423 tip portion, 431 first recess, 432 second recess portion, L2 axis, SP support portion

Claims (8)

Seat cushion and
A seat back connected to a rear end of the seat cushion;
a support portion that is disposed below a connection point between the seat cushion and the seat back and that supports the seat back rotatably about an axis extending in a substantially horizontal direction within a predetermined rotation range that includes a reclined position of the seat back and an upright position,
The support portion has a biasing member that biases the seat back, which is located in the reclined position, in an 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 includes a first biasing member and a second biasing member that bias the seat back in the upright direction with biasing forces different from each other ,
the first biasing member and the second biasing member are configured by spiral springs having a width of a predetermined length substantially parallel to the axis and wound radially outward;
The support portion further includes a holding portion that protrudes from the seat back substantially parallel to the axis and holds a radial outer end portion of the first biasing member and a radial outer end portion of the second biasing member,
the retaining portion has a first recess formed in a concave shape across the width direction of the first biasing member so as to retain a radially outer end portion of the first biasing member, and a second recess formed in a concave shape across the width direction of the second biasing member so as to retain a radially outer end portion of the second biasing member,
The seat support device according to claim 1, wherein the first recess and the second recess are provided at different positions in a rotation direction of the seat back . 2. The seat support device according to claim 1,
A seat support device, wherein a radially inner end portion of the first biasing member and a radially inner end portion of the second biasing member are attached to different members. 2. The seat support device according to claim 1,
A seat support device, characterized in that a widthwise end of the first biasing member and a widthwise end of the second biasing member are located inside of a tip end of the holding portion in the substantially horizontal direction. The seat support device according to any one of claims 1 to 3,
The seat support device, wherein the first biasing member and the second biasing member are disposed substantially outboard of the locking mechanism in the horizontal direction. 3. The seat support device according to claim 1,
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,
a lock mechanism and a first biasing member disposed on the first frame, and a second biasing member disposed on the second frame, the lock mechanism and the first biasing member being disposed on the first frame; The seat support device according to any one of claims 1 to 4,
A damping device that exerts a damping force acting in a direction opposite to a 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,
A seat support device, characterized in that at least one of the first biasing member and the second biasing member is disposed on the first frame, and the damping device is disposed on the second frame. The seat cushion includes a seat back connected to a rear end of the seat cushion, and a support portion disposed below a connection point between the seat cushion and the seat back, and configured to support the seat back rotatably about an axis extending in a substantially horizontal direction within a predetermined rotation range including a reclined position in which the seat back is reclined to an upright position, the support portion being ... a lock mechanism that holds the seat back in the reclined position; and a holding portion that protrudes from the seat back substantially parallel to the axis and holds a radially outer end of the first biasing member and a radially outer end of the second biasing member, the holding portion having a first recess that is formed in a concave shape across the width of the first biasing member so as to hold the radially outer end of the first biasing member, and a second recess that is formed in a concave shape across the width of the second biasing member so as to hold the radially outer end of the second biasing member,
attaching the seat back to the seat cushion so as to be rotatable about the axis;
attaching the locking mechanism to a side surface of the seat cushion;
a step of attaching the first biasing member, which is spirally wound around the axis, to the first recess;
The method for manufacturing a seat support device further comprises the step of attaching the second biasing member, which is spirally wound around the axis, to the second recess. A vehicle seat comprising the seat support device according to any one of claims 1 to 6.

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