JP7804187B2 - Vehicle seat and method for manufacturing vehicle seat - Google Patents

Description

The present invention relates to a vehicle seat equipped with a pair of reclining units that tilt the seat back relative to the seat cushion, and a method for manufacturing the same.

The vehicle seat disclosed in Patent Document 1 below is a known example of a vehicle seat equipped with a pair of reclining units that tilt the seat back relative to the seat cushion. This vehicle seat is equipped with a right-side reclining unit and a left-side reclining unit that are configured in reverse, and a connecting rod (a long connecting member). The hinge pin (shaft) of the right-side reclining unit and the hinge pin of the left-side reclining unit are connected by the connecting rod, so that the right-side reclining unit and the left-side reclining unit can be locked off in sync.

JP 2018-094990 A

In the process of connecting the shafts of the left and right reclining units to the long connecting member, each shaft is rotated to a predetermined rotational position (for example, a position rotated in the lock-off direction) and then welding or other work is performed to connect the components while maintaining the alignment of their rotational centers. This is because connecting the shafts without aligning their rotational positions will result in misalignment of the lock-off timing of the left and right reclining units.

However, in the above-mentioned work process of aligning the rotational positions of shafts before welding, the equipment required is complicated, including jigs for aligning the rotational positions of each shaft, making it difficult to improve production takt time.

The present invention was made to solve the above-mentioned problems, and its purpose is to provide a configuration that can improve the synchronization of both reclining units without making the connection process complicated.

In order to achieve the above object, the invention of claim 1 described in the claims comprises:
a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A vehicle seat comprising:
the connecting member includes a main body having a flat bottom surface and a pair of connecting pieces connected to the main body at both ends thereof so as to face each other via the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed, facing each other in an inclined state with a planar opposing surface partially contacting the bottom surface of the connecting member;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
The shaft is characterized in that, when fixed by welding, the rotation center of the shaft is positioned on a predetermined rotation axis and the opposing surface is arranged at a predetermined inclination angle with respect to the bottom surface.

The invention of claim 2 is as follows:
a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A vehicle seat comprising:
the connecting member includes a main body portion having a flat bottom surface, a pair of connecting pieces connected to the main body portion at both ends thereof so as to face each other via the bottom surface, and a protrusion provided on the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed in a state in which the planar opposing surfaces of the shaft face the bottom surface of the connecting member with a predetermined gap therebetween;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
When fixed by welding, the shaft is arranged so that its rotation center is located on a predetermined rotation axis line,
The protrusion is provided at a position on the bottom surface where it pushes and rotates the opposing surface when the base is welded and fixed.

The invention of claim 3 is as follows:
a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A method for manufacturing a vehicle seat comprising:
the connecting member includes a main body having a flat bottom surface and a pair of connecting pieces connected to the main body at both ends thereof so as to face each other via the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed, facing each other in an inclined state with a planar opposing surface partially contacting the bottom surface of the connecting member;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
a step of positioning the one reclining unit and the other reclining unit so that the rotation centers of the respective shafts are positioned on a predetermined rotation axis line;
pressing the connecting member against the shaft so that the opposing surface is inclined at a predetermined angle with respect to the bottom surface;
welding and fixing the pair of connecting pieces to the shaft while pressing the connecting member against the shaft;
The present invention is characterized by comprising:

The invention of claim 4 is as follows:
a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A method for manufacturing a vehicle seat comprising:
the connecting member includes a main body portion having a flat bottom surface, a pair of connecting pieces connected to the main body portion at both ends thereof so as to face each other via the bottom surface, and a protrusion provided on the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed in a state in which the planar opposing surfaces of the shaft face the bottom surface of the connecting member with a predetermined gap therebetween;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
a step of positioning the one reclining unit and the other reclining unit so that the rotation centers of the respective shafts are positioned on a predetermined rotation axis line;
pressing the coupling member against the shaft so that the protrusion presses against the opposing surface;
welding and fixing the pair of connecting pieces to the shaft while pressing the connecting member against the shaft;
The present invention is characterized by comprising:

In the invention of claim 1, the elongated connecting member for connecting one reclining unit and the other reclining unit so that they rotate synchronously is configured to include a main body with a flat bottom surface and a pair of connecting pieces connected to the main body at both ends so as to face each other via the bottom surface. The shafts of the one reclining unit and the other reclining unit are formed so that the pair of connecting pieces are welded and fixed to the bottom surface of the connecting member, with the flat opposing surfaces partially in contact and facing each other in an inclined state. When welded and fixed, the rotation center of the shaft is located on a predetermined rotation axis, and the opposing surfaces are positioned at a predetermined inclination angle relative to the bottom surface.

As a result, by pressing the connecting member against the shaft before welding, the contact area on the opposing surface of the shaft is pressed down by the bottom surface of the connecting member, causing the shaft to rotate to a position where it can push and rotate the locking member. Therefore, simply by welding the pair of connecting pieces of the pressed connecting member to the shaft as described above, the rotational positions of both shafts can be aligned by welding, thereby improving the synchronization of both reclining units without making the connection process complicated.

In the invention of claim 2, the elongated connecting member for connecting one reclining unit and the other reclining unit so that they rotate synchronously is configured to include a main body with a flat bottom surface, a pair of connecting pieces connected to the main body at both ends so as to face each other via the bottom surface, and a protrusion provided on the bottom surface. The one reclining unit and the other reclining unit are positioned so that the rotation center of the shaft is located on a predetermined rotation axis when welded and fixed. The protrusion is provided on the bottom surface in a position that pushes and rotates the opposing surface when welded and fixed.

As a result, by pressing the connecting member against the shaft before welding, the protrusion on the bottom surface presses down on the contact area on the opposing surface of the shaft, causing the shaft to rotate to a position where it can push and rotate the locking member. Therefore, simply by welding the pair of connecting pieces of the pressed connecting member to the shaft as described above, the rotational positions of both shafts can be aligned by welding, thereby improving the synchronization of both reclining units without making the connection process complicated.

In the invention of claim 3, the elongated connecting member for connecting one reclining unit and the other reclining unit so that they rotate synchronously is configured to include a main body with a flat bottom surface and a pair of connecting pieces connected to the main body at both ends so that they face each other via the bottom surface. The one reclining unit and the other reclining unit are then positioned so that the rotation centers of their respective shafts are located on predetermined rotation axes, and the pair of connecting pieces are welded and fixed to the shaft with the connecting member pressed against the shaft so that the opposing surfaces form a predetermined inclination angle with respect to the bottom surface.

As a result, when the connecting member is pressed against the shaft, the contact area on the opposing surface of the shaft is pressed down by the bottom surface of the connecting member, causing the shaft to rotate to a position where it can push and rotate the locking member. Therefore, simply by welding the pair of connecting pieces of the pressed connecting member to the shaft as described above, the rotational positions of both shafts can be aligned by welding and fixed, improving the synchronization of both reclining units without making the connection process complicated.

In the invention of claim 4, the elongated connecting member for connecting one reclining unit and the other reclining unit so that they rotate synchronously is configured to include a main body with a flat bottom surface, a pair of connecting pieces connected to the main body at both ends of the main body so that they face each other via the bottom surface, and a protrusion provided on the bottom surface. The one reclining unit and the other reclining unit are then positioned so that the rotation centers of their respective shafts are located on predetermined rotation axes, and the pair of connecting pieces are welded and fixed to the shaft with the connecting member pressed against the shaft so that the protrusions press and rotate the opposing surfaces.

As a result, when the connecting member is pressed against the shaft, the protrusion on the bottom surface presses down on the contact area on the opposing surface of the shaft, causing the shaft to rotate to a position where it can push and rotate the locking member. Therefore, simply by welding the pair of connecting pieces of the pressed connecting member to the shaft as described above, the rotational positions of both shafts can be aligned by welding and fixed, improving the synchronization of both reclining units without making the connection process complicated.

1 is a side view showing an outline of the configuration of a vehicle seat according to the present invention; FIG. FIG. 4A is a view of the second reclining unit taken along a cross section corresponding to line X1-X1 in FIG. 3, and FIG. 4B is an enlarged view of the shaft and its vicinity in FIG. 4A. FIG. 4 is a cross-sectional view of the first reclining unit. 6 is a cross-sectional view taken along the line X2-X2 of FIG. 5. 6 is a cross-sectional view taken along a line X3-X3 shown in FIG. 5. FIG. 10 is a perspective view of a shaft of the first reclining unit. 9 is a view of the shaft in FIG. 8 as seen from the connecting member side. 10A and 10B are explanatory diagrams illustrating the positional relationship between the shaft and the connecting member before and after welding in the first embodiment, in which FIG. 10A shows the state before the shaft is pressed by the connecting member, and FIG. 10B shows the state after the shaft is pressed by the connecting member and welded. FIG. 10 is a perspective view of a shaft in a vehicle seat according to a second embodiment. 12 is a view of the shaft in FIG. 11 as seen from the connecting member side. FIG. 13A and 13B are explanatory diagrams illustrating the positional relationship between the shaft and the connecting member before and after welding in the second embodiment, in which FIG. 13A shows the state before the shaft is pressed by the connecting member, and FIG. 13B shows the state after the shaft is pressed by the connecting member and welded. FIG. 11 is a cross-sectional view of a reclining unit that is a main part of a vehicle seat according to a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle seat according to the present invention will now be described with reference to the drawings.
As shown in FIG. 1, the vehicle seat 10 of the present invention mainly comprises a seat cushion 11, a seat back 12, and a reclining device 20. A seat bracket (lower bracket) 11a is fixed to the seat cushion 11, and a seat back bracket (upper bracket) 12a is fixed to the seat back 12.

The lower bracket 11a and upper bracket 12a are fixed to the respective pivotal positions of the pair of left and right round reclining units of the reclining device 20, thereby connecting them to each other so that they can pivot relative to each other. This allows the tilt angle of the seat back 12 relative to the seat cushion 11 to be adjusted.

As shown in Figures 1 to 3, the reclining device 20 includes a pair of left and right round reclining units (hereinafter referred to as the first reclining unit 21a and the second reclining unit 21b), a long connecting member 22 for connecting the first reclining unit 21a and the second reclining unit 21b so that they rotate synchronously, and a reclining operation lever 23 for manual operation. For convenience, the reclining operation lever 23 is not shown in Figures 2 and 3. The first reclining unit 21a can be an example of "one reclining unit," and the second reclining unit 21b can be an example of "the other reclining unit."

The shaft 24a of the first reclining unit 21a and the shaft 24b of the second reclining unit 21b are connected by a connecting member 22 so that they rotate synchronously, and a reclining operation lever 23 is attached to the shaft 24a. Therefore, in response to operation of the reclining operation lever 23, the first reclining unit 21a and the second reclining unit 21b operate synchronously.

Specifically, when the reclining operation lever 23 is pulled upward, the reclining device 20 enters an unlocked state, allowing the tilt angle of the seatback 12 to be adjusted. The range of angle A shown in Figure 1 when the seatback 12 is tilted backward is the tilt adjustment range in which the seatback 12 locks in that angle position when the reclining operation lever 23 is released. The range of angle B shown in Figure 1 when the seatback 12 is tilted forward is the free rotation range corresponding to the unlocked state in which the seatback remains unlocked even when the reclining operation lever 23 is released. As can be seen from Figure 1, the seatback 12 can be rotated from a forward-tilted position in which it contacts the seat cushion 11 to a backward-tilted position in which it is flat against the seat cushion 11.

Since the first reclining unit 21a and the second reclining unit 21b are basically symmetrical in shape, the first reclining unit 21a will be taken as an example for explanation.
As shown in Figures 2, 3, and 5, the first reclining unit 21a is configured by overlapping an approximately circular base plate 30 and an approximately bowl-shaped gear plate 40 and assembling a cover bracket 50, so that the base plate 30 and the gear plate 40 are held so as to be able to rotate relative to each other and relative movement in the axial direction is suppressed.

A cavity (space) C is formed between the base plate 30 and the gear plate 40. As shown in Figures 5 to 7, this cavity C contains four lock gears: a pair of first lock gears 61 and a pair of second lock gears 62; a central cam 70; two biasing members 80; and a generally disk-shaped cam lever 90, among other components for locking and unlocking. For convenience, Figures 6 and 7 only show the area near the internal teeth 41 of the gear plate 40, and do not include the cover bracket 50.

The base plate 30 has multiple protrusions formed on its outer side, and is attached to the lower bracket 11a by engaging each of these protrusions with engaging holes in the lower bracket 11a. Furthermore, the base plate 30 has guide surfaces formed on its side facing the gear plate 40 to guide the lock gears 61, 62 in the radial direction. The base plate 30 can be considered an example of a "first plate" attached to the seat cushion 11.

Internal teeth 41 are formed around the entire inner circumferential surface of the gear plate 40. The gear plate 40 has multiple protrusions formed on its back surface (the surface on the other axial side), and is attached to the upper bracket 12a by engaging each of these protrusions with an engaging hole in the upper bracket 12a.

In addition, two arcuate steps formed coaxially with the internal teeth 41 are arranged at 180° intervals on the inner peripheral surface of the gear plate 40. These arcuate steps are intended to achieve the above-mentioned lock-free state, and are formed so that the angular range in which the protrusion 61c (described below) of the first lock gear 61 abuts from the inner peripheral side corresponds to the above-mentioned free rotation range. The gear plate 40 can be considered an example of a "second plate" attached to the seat back 12.

As shown in FIG. 6, external teeth 61a, 62a that can mesh with the internal teeth 41 of the gear plate 40 are formed on the outer periphery of both first lock gears 61 and both second lock gears 62. Each lock gear 61, 62 is assembled so that it is guided radially and slidably using the respective guide surfaces of the base plate 30. Furthermore, protrusions 61b, 61c that are used to control the radial movement of the first lock gear 61 are formed on the gear plate 40 side of both first lock gears 61. Furthermore, protrusions 62b that are used to control the radial movement of the second lock gear 62 are formed on the gear plate 40 side of both second lock gears 62.

The movable guides 37 are wedge-shaped, with their width gradually narrowing from one end to the other. They are slidably disposed between the first lock gear 61 and the guide surface of the base plate 30. Each movable guide 37 has an engagement hole 37a for engaging one end of a biasing member 80. By engaging one end of the biasing member 80 with this engagement hole 37a, the biasing member 80 biases each movable guide 37 inward toward the base plate 30. As a result, the movable guide 37 is constantly wedged between the first lock gear 61 and the guide surface of the base plate 30. The first lock gear 61, the guide surfaces of the base plate 30, and the movable guide 37 are tightly fitted together, eliminating any gaps in the rotational direction between the components. This eliminates backlash in the fore-and-aft direction of the seat back 12.

A plate-shaped cam 70 with a generally cross-shaped through-hole 71 formed in its center for engagement is rotatably disposed in the center of the base plate 30. The cam 70 is configured so that when rotated in the unlocking direction, it abuts against the lock gears 61, 62 from the radially inner side, thereby meshing the external teeth 61a, 62a with the internal teeth 41 of the gear plate 40. The cam 70 also has two engagement holes 73 into which the other ends of the two biasing members 80 respectively engage, and two cylindrical protrusions 74 for assembling the cam lever 90.

As shown in Figure 7, the cam 70 is strongly biased in the locking direction (clockwise in Figures 6 and 7) by engaging with two biasing members 80. As a result, the cam surface on the outer periphery of the cam 70 abuts against the inner end surfaces of the locking gears 61 and 62, and the biasing forces in the locking direction from the two biasing members 80 strongly bias the locking gears 61 and 62 radially outward.

The fitting portion 26 of the shaft 24a is inserted into the through-hole 71 of the cam 70, and by rotating this shaft 24a, the cam 70 can be rotated in the unlocking direction (counterclockwise in Figures 6 and 7) against the biasing forces of both biasing members 80. The cam 70 can be considered an example of a "locking member."

As shown in Figure 7, the cam lever 90 has a through hole 91 that fits over both protrusions 74 of the cam 70, as well as two cam holes 92 and two cam holes 93. The cam lever 90 is assembled to the gear plate 40 side of the cam 70 with both through holes 91 and both protrusions 74 fitted together, the protrusion 61b inserted into both cam holes 92, and the protrusion 62b inserted into both cam holes 93.

As a result, when the cam lever 90 rotates in the unlocking direction together with the cam 70, the inner peripheral edge of the cam hole 92 abuts against the protrusion 61b of the first lock gear 61, and the inner peripheral edge of the cam hole 93 abuts against the protrusions 62b of both second lock gears 62. Furthermore, when the cam lever 90 rotates in the unlocking direction, the protrusions 61b and 62b are biased radially inward by the inner peripheral edges of the cam holes 92 and 93, causing the lock gears 61 and 62 to move radially inward in unison, thereby disengaging the external teeth 61a and 62a from the internal teeth 41 of the gear plate 40. In other words, the locked and unlocked states are controlled according to the rotational states of the cam 70 and cam lever 90. The cam lever 90 can be considered an example of a "release member" that can release the meshing between the external teeth 61a and 62a and the internal teeth 41 by rotating the cam 70 against the biasing force of a biasing member.

As shown in Figures 8 and 9, the shaft 24a is formed to have a large diameter portion 25, a fitting portion 26, and a support portion 27. The large diameter portion 25 is formed so that it is exposed to the outside from the base plate 30 when the fitting portion 26 fits into the through hole 71 of the cam 70, and a screw hole 25a is formed on its end face for assembling the reclining operation lever 23. The fitting portion 26 is formed to have a generally cross-shaped cross section so that its center of rotation coincides with the through hole 71 of the cam 70 when it fits into it.

The support portion 27 is formed so as to be exposed to the outside from the gear plate 40 when the fitting portion 26 fits into the through hole 71 of the cam 70. The support portion 27 is formed with a generally rectangular cross section, with a pair of outer surfaces 27a facing each other on the long side of the cross section and a pair of outer surfaces 27b facing each other on the short side of the cross section. In particular, as shown in Figure 9, in this embodiment, the plane of the support portion 27 along the outer surface 27a is formed at an acute angle θ1 in the unlocking direction with respect to a plane containing one of the cross lines based on the cross-sectional shape of the fitting portion 26 (hereinafter simply referred to as the reference plane S).

The second reclining unit 21b is basically formed with a shape that is the symmetrical one to the first reclining unit 21a. The shaft 24b has the same shape as the shaft 24a, and since the reclining operation lever 23 cannot be attached to it, the male thread portion 28 is threaded into the threaded hole 25a.

The connecting member 22 has a generally U-shaped cross section and includes a main body 22a with a flat bottom surface 22b and a pair of connecting pieces 22c connected to the main body 22a at both ends thereof so as to face each other via the bottom surface 22b. Both ends of the connecting member 22 are welded to the support portion 27 of the shaft 24a exposed from the gear plate 40 of the first reclining unit 21a and the support portion 27 of the shaft 24b exposed from the gear plate 40 of the second reclining unit 21b, respectively.

In particular, in this embodiment, as shown in FIG. 4(B), the pair of connecting pieces 22c of the connecting member 22 are welded to the support portion 27 in a state where the outer surface 27a of the connecting member 22 is in partial contact with the bottom surface 22b, facing the bottom surface 22b at an inclined state with a predetermined inclination angle θ2 (see symbol W in FIG. 4(B)). In this welded and fixed state, the support portion 27 is subjected to a pressing force from the connecting member 22 that rotates it in the locking direction. By welding and fixing the connecting member 22 in this manner, the shafts 24a and 24b are connected so that they rotate synchronously, thereby synchronizing the locking and unlocking timings of the first reclining unit 21a and the second reclining unit 21b. The outer surface 27a can be considered an example of an "opposing surface."

With this configuration, in the first reclining unit 21a and the second reclining unit 21b, the cam 70, which serves as the locking member, is pushed and rotated by the rotating shafts 24a, 24b, and the base plate 30 and gear plate 40, which are now in a relatively rotatable state, rotate relative to each other around the rotation centers of the shafts 24a, 24b in response to the rotation of the shafts 24a, 24b. This causes the seat back 12 to tilt relative to the seat cushion 11.

Here, the manufacturing process (step) of welding the connecting member 22 using both support portions 27 will be described with reference to FIGS.
First, the first reclining unit 21a and the second reclining unit 21b are assembled to the corresponding portions of the lower bracket 11a and the upper bracket 12a so that the rotation centers of the respective shafts 24a, 24b are positioned on the predetermined rotation axis L (see FIG. 3). At this time, as shown in FIG. 10(A), the first reclining unit 21a and the second reclining unit 21b are positioned so that the reference plane S of the shaft 24a and the reference plane S of the shaft 24b are approximately perpendicular to the pressing direction F from the connecting member 22 (described later) (for example, so that the reference plane S is along a horizontal plane) (first step).

Next, the connecting member 22 is positioned on the shafts 24a, 24b so that the bottom surface 22b is parallel to the reference plane S and the edge of the outer surface 27a is in approximately linear contact with the bottom surface 22b. In this positioned state (where the bottom surface 22b is not pressing against the outer surface 27a), as can be seen in Figure 10(A), the inclination angle of the outer surface 27a relative to the bottom surface 22b is approximately equal to the angle θ1 described above. Then, from the positioned state described above, the connecting member 22 is pressed against the support portion 27 along the pressing direction F (see Figure 10(A)) (second step).

As a result, as shown in Figure 10 (B), both support portions 27 rotate in the locking direction by the amount of pressure applied, causing the shaft 24a of the first reclining unit 21a and the shaft 24b of the second reclining unit 21b to rotate to their locked positions and stop rotating. In this rotated state, the inclination angle of the outer surface 27a relative to the bottom surface 22b decreases from angle θ1 to the predetermined inclination angle θ2 described above.

With the connecting member 22 pressed against the support portion 27 in this manner until the rotation of both shafts 24a and 24b stops, the pair of connecting pieces 22c are welded and fixed to the support portions 27 of the shafts 24a and 24b (third step).

In this way, the pair of connecting pieces 22c are welded to both support portions 27 while the connecting member 22 is pressed against both shafts 24a, 24b. This allows the welding work to be performed without the need for jigs or other tools for adjusting the rotational positions of both shafts 24a, 24b to synchronize the first reclining unit 21a and the second reclining unit 21b.

As described above, in the vehicle seat 10 according to this embodiment, the elongated connecting member 22 for connecting the first reclining unit 21a and the second reclining unit 21b so that they rotate synchronously is configured to include a main body 22a with a flat bottom surface 22b and a pair of connecting pieces 22c connected to the main body 22a at both ends of the main body 22a so as to face each other via the bottom surface 22b. The shaft 24a of the first reclining unit 21a and the shaft 24b of the second reclining unit 21b are formed so that the pair of connecting pieces 22c are welded and fixed to the bottom surface 22b of the connecting member 22, with the flat outer surface 27a partially in contact with the bottom surface 22b. When welded and fixed, the rotation centers of the shafts 24a, 24b are positioned on the predetermined rotation axis L, and the outer surface 27a is at a predetermined inclination angle θ2 with respect to the bottom surface 22b.

As a result, by pressing the connecting member 22 against the shafts 24a, 24b before welding, the contact portions of the outer surfaces 27a of the shafts 24a, 24b are pressed down by the bottom surface 22b of the connecting member 22, causing the shafts 24a, 24b to rotate to a position where they can push and rotate the cam 70, etc. Therefore, simply by welding the pair of connecting pieces 22c of the pressed connecting member 22 to the shafts 24a, 24b, respectively, the rotational positions of the two shafts 24a, 24b can be aligned by welding, thereby improving the synchronization of the two reclining units 21a, 21b without making the connection process complicated.

In addition, the manufacturing method for the vehicle seat 10 according to this embodiment involves positioning the first reclining unit 21a and the second reclining unit 21b so that the rotation centers of the respective shafts 24a, 24b are located on the predetermined rotation axis L, and then pressing the connecting member 22 against the shafts 24a, 24b so that the outer surface 27a is at the predetermined inclination angle θ2 relative to the bottom surface 22b, and then welding and fixing the pair of connecting pieces 22c to the shafts 24a, 24b.

As a result, when the connecting member 22 is pressed against the shafts 24a, 24b, the contact portions of the outer surfaces 27a of the shafts 24a, 24b are pressed down by the bottom surfaces 22b of the connecting member 22, causing the shafts 24a, 24b to rotate to a position where they can push and rotate the cam 70, etc. Therefore, simply by welding the pair of connecting pieces 22c of the pressed connecting member 22 to the shafts 24a, 24b as described above, the rotational positions of the two shafts 24a, 24b can be aligned by welding and fixing them, thereby improving the synchronization of the two reclining units 21a, 21b without making the connection process complicated.

Second Embodiment
Next, a vehicle seat according to a second embodiment of the present invention will be described.
In the second embodiment, the main difference from the first embodiment is the shape of the shaft and the connecting member that pushes and turns the shaft when the connecting member is welded and fixed in place. Therefore, the same reference numerals are used to designate components that are essentially the same as those in the first embodiment, and descriptions thereof will be omitted.

In this embodiment, shafts 110a, 110b and a connecting member 120 are used instead of the shafts 24a, 24b and connecting member 22 of the first embodiment. As shown in Figures 11 and 12, shafts 110a, 110b are formed with respect to shaft 24a so that the plane along the outer surface 27a of the support portion 27 is parallel to the reference plane S. Therefore, a pair of connecting pieces 22c of shafts 110a, 110b are welded and fixed to the bottom surface 22b of connecting member 120 with a predetermined gap between them at the outer surface 27a.

As shown in Figures 13(A) and 13(B), in addition to the main body 22a and pair of connecting pieces 22c described above, the connecting member 120 also has embossments 121 provided as protrusions on both longitudinal ends of the bottom surface 22b. The embossments 121 are formed in positions that push and rotate the outer surface 27a in the locking direction when the bottom surface 22b is brought close to the outer surface 27a during welding and fixation.

In this embodiment, in the manufacturing process (step) of welding the connecting member 120 to both shafts 110a, 110b, the shaft 110a assembled to the first reclining unit 21a and the shaft 110b of the second reclining unit 21b are assembled to the corresponding portions of the lower bracket 11a and the upper bracket 12a so that their respective rotation centers are positioned on the predetermined rotation axis L. At this time, as shown in FIG. 13(A), the first reclining unit 21a and the second reclining unit 21b are positioned so that the reference plane S of the shaft 110a and the reference plane S of the shaft 110b are approximately perpendicular to the pressing direction F from the connecting member 120 (so that the outer surface 27a is approximately perpendicular to the pressing direction F) (first step).

Next, the connecting member 120 is positioned on the shafts 110a, 110b so that the bottom surface 22b is parallel to the reference plane S and the embossment 121 is in contact with the outer surface 27a. In this positioned state (where the embossment 121 is not pressing against the outer surface 27a), as can be seen in Figure 13(A), the outer surface 27a of the support portion 27 faces the bottom surface 22b of the connecting member 120 in a substantially parallel state with a predetermined gap between them. Then, from the above-described positioned state, the connecting member 120 is pressed against the support portion 27 in the pressing direction F (see Figure 13(A)) so that the embossment 121 presses against the outer surface 27a (second step).

As a result, as shown in Figure 13 (B), both support parts 27 rotate in the locking direction by the amount of pressure applied, causing the shaft 110a of the first reclining unit 21a and the shaft 110b of the second reclining unit 21b to rotate to their respective locking positions and stop rotating.

With the connecting member 120 pressed against the support portion 27 in this manner until the rotation of both shafts 110a, 110b stops, the pair of connecting pieces 22c are welded and fixed to the support portions 27 of the shafts 110a, 110b (third step).

In this way, the pair of connecting pieces 22c are welded to both support portions 27 while the connecting member 22 is pressed against both shafts 24a, 24b. This allows the welding work to be performed without the need for jigs or other tools for adjusting the rotational positions of both shafts 24a, 24b to synchronize the first reclining unit 21a and the second reclining unit 21b.

As described above, in the vehicle seat 10 according to this embodiment, the elongated connecting member 120 for connecting the first reclining unit 21a and the second reclining unit 21b so that they rotate synchronously is configured to include a main body 22a with a flat bottom surface 22b, a pair of connecting pieces 22c connected to the main body 22a at both ends of the main body 22a so as to face each other via the bottom surface 22b, and an embossment (protrusion) 121 provided on the bottom surface 22b. The first reclining unit 21a and the second reclining unit 21b are positioned so that the rotation centers of the shafts 110a, 110b are located on a predetermined rotation axis L when the units are welded together. The embossment 121 is provided at a position on the bottom surface 22b that will push and rotate the outer surface 27a when the units are welded together.

As a result, by pressing the connecting member 120 against the shafts 110a, 110b before welding, the embossments 121 on the bottom surface 22b press down on the contact areas of the outer surfaces 27a of the shafts 110a, 110b, causing the shafts 110a, 110b to rotate to a position where they can push and rotate the cam 70, etc. Therefore, simply by welding the pair of connecting pieces 22c of the connecting member 120 pressed as described above to the shafts 110a, 110b, respectively, the rotational positions of the two shafts 110a, 110b can be aligned by welding, thereby improving the synchronization of the two reclining units 21a, 21b without making the connection process complicated.

In addition, the manufacturing method for the vehicle seat 10 according to this embodiment involves positioning the first reclining unit 21a and the second reclining unit 21b so that the rotation centers of the respective shafts 110a, 110b are positioned on the predetermined rotation axis L, and then welding and fixing the pair of connecting pieces 22c to the shafts 110a, 110b with the connecting member 120 pressed against the shafts 110a, 110b so that the embossments 121 press and rotate the outer surface 27a.

As a result, when the connecting member 120 is pressed against the shafts 110a, 110b, the embossments 121 on the bottom surface 22b press down on the contact areas of the outer surfaces 27a of the shafts 110a, 110b, causing the shafts 110a, 110b to rotate to a position where they can push and rotate the cam 70, etc. Therefore, simply by welding the pair of connecting pieces 22c of the connecting member 120 pressed as described above to the shafts 110a, 110b, the rotational positions of the two shafts 110a, 110b can be aligned by welding, thereby improving the synchronization of the two reclining units 21a, 21b without making the connection process complicated.

[Third embodiment]
Next, a vehicle seat according to a third embodiment of the present invention will be described.
The third embodiment differs from the first embodiment mainly in that the structures of both reclining units are modified. Therefore, components that are substantially the same as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

The first reclining unit (one of the reclining units) 221a and the second reclining unit (the other reclining unit) 221b in this embodiment operate using the driving force of a motor. As with the first embodiment described above, each shaft is formed so that a pair of connecting pieces 22c are welded and fixed to the bottom surface 22b of the connecting member 22, facing each other in an inclined state with the outer surface 27a partially in contact with the bottom surface 22b. When welded and fixed, the center of rotation of the shaft is positioned on a predetermined rotation axis, and the outer surface 27a is positioned at a predetermined inclination angle with respect to the bottom surface 22b.

Specifically, the first reclining unit 221a is configured to include an external gear 230 attached to the lower bracket 11a, an internal gear 240 attached to the upper bracket 12a, a shaft 250, a U-shaped bushing 261 that functions as a locking member, a pair of wedge-shaped cams 262, a spring 263, a plate cover 270, a shaft cover (not shown), and the like.

The external gear 230 has external teeth 231 formed on its outer periphery and a generally cylindrical boss portion 232 formed in its center. The external gear 230 can be considered an example of a "first plate" attached to the seat cushion 11.

The internal gear 240 is configured to include a cylindrical portion with internal teeth 241 formed on its inner circumferential surface, and a side plate portion with a generally cylindrical boss portion 242 formed in its center. The internal teeth 241 mesh eccentrically with the external teeth 231, and are therefore formed with a greater number of teeth than the external teeth 231. A resin bearing 243 is fitted inside the boss portion 242 of the internal gear 240, and a U-shaped bushing 261 and a pair of wedge-shaped cams 262 are disposed between the inner circumferential surface of the boss portion 242 formed by this resin bearing 243 and the outer circumferential surface of the boss portion 232 of the external gear 230. The internal gear 240 may serve as an example of a "second plate" attached to the seat back 12.

The shaft 250 is configured to include a support portion 27 exposed to the outside in the positional relationship described above, a U-shaped main body portion 251 with serrations formed on its inner surface that fits coaxially with the inner circumferential surface of the boss portion 232 of the external gear 230, and a U-shaped portion 252 that covers part of the outer circumferential surface of the boss portion 232 into which the U-shaped main body portion 251 fits. The U-shaped portion 252 abuts at both rotational end faces against both rotational end faces of a U-shaped bushing 261 incorporated into the inner circumferential side of the boss portion 242 of the internal gear 240. The U-shaped portion 252 is configured to push and rotate one wedge-shaped cam 262 when rotating in a rotational direction that tilts the seat back 12 forward (forward tilt rotation direction), and to push and rotate the other wedge-shaped cam 262 when rotating in a rotational direction that tilts the seat back 12 backward (rearward tilt rotation direction).

The wedge-shaped cam 262 is formed in a wedge shape so that its radial thickness decreases toward the tip. The wedge-shaped cam 262 is interposed between the outer circumferential surface of the boss portion 232 of the external gear 230 and the U-shaped bushing 261, with its tip end face facing the end face of the U-shaped portion 252 in the rotation direction, and is positioned so that it is pressed against both the outer circumferential surface of the boss portion 232 and the U-shaped bushing 261 by being biased from the base end by the spring 263.

When the pair of wedge-shaped cams 262 are pressed as described above, the internal gear 240 becomes eccentric with respect to the external gear 230, and some of the external teeth 231 mesh with the internal teeth 241. In this eccentric state, the external gear 230 rotates relative to the internal gear 240 as described below, causing the external gear 230 to revolve around the gear axis of the internal gear 240, changing the meshing position between the external teeth 231 and the internal teeth 241. Furthermore, when the pair of wedge-shaped cams 262 are pressed against both the outer circumferential surface of the boss portion 232 and the U-shaped bushing 261 by the spring 263 so that they move away from each other, the pair of wedge-shaped cams 262 are interposed at predetermined positions, restricting the relative rotation between the external gear 230 and the internal gear 240.

The plate cover 270 is assembled to the internal gear 240 so as to prevent axial misalignment of the external gear 230 relative to the internal gear 240. The shaft cover is assembled to the internal gear 240 so as to prevent axial misalignment of the shaft 250 relative to the internal gear 240.

The first reclining unit 221a configured in this manner is welded and fixed to the lower bracket 11a using multiple protrusions formed on the side of the external gear 230, and is welded and fixed to the upper bracket 12a using multiple protrusions formed on the side of the internal gear 240.

The second reclining unit 221b is basically formed in a symmetrical shape to the first reclining unit 221a.

The connecting member 22 has both ends welded to the support portion 27 of the exposed shaft 250 of the first reclining unit 221a and the support portion 27 of the exposed shaft 250 of the second reclining unit 21b. By welding the connecting member 22 in this way, the two shafts 250 are connected so that they rotate synchronously.

With this configuration, in the first reclining unit 221a and the second reclining unit 221b, when both shafts 250 do not rotate, the pair of wedge-shaped cams 262 restrict the relative rotation of the external gear 230 and the internal gear 240, thereby maintaining the tilt angle of the seat back 12 relative to the seat cushion 11.

When the motor is driven in response to a forward tilting operation and both shafts 250 rotate in the forward tilting direction, one of the two wedge-shaped cams 262, which is rotating in the opposite direction to the rotation direction, is pushed and rotated by the U-shaped portion 252 against the biasing force of the spring 263, thereby releasing the above-mentioned pressing state of the one wedge-shaped cam 262. As a result, the external gear 230, which rotates relative to the internal gear 240, rotates together with the shaft 250 in the forward tilting direction, causing the seat back 12 to tilt forward relative to the seat cushion 11.

On the other hand, when the motor is driven in response to a rearward tilting operation and both shafts 250 rotate in the rearward tilting direction, the other of the two wedge-shaped cams 262, which rotates in the opposite direction to the rotation direction, is pushed and rotated by the U-shaped portion 252 against the biasing force of the spring 263, thereby releasing the above-mentioned pressing state of the other wedge-shaped cam 262. As a result, the external gear 230, which rotates relative to the internal gear 240, rotates together with the shaft 250 in the rearward tilting direction, causing the seat back 12 to tilt rearward relative to the seat cushion 11.

In this embodiment, in the manufacturing process for welding the connecting member 22 using both support portions 27, similar to the first embodiment, the first reclining unit 221a and the second reclining unit 221b are positioned so that the rotation center of each shaft 250 is located on the predetermined rotation axis L. The connecting member 22 is then pressed against the shaft 250 so that the outer surface 27a is at a predetermined inclination angle relative to the bottom surface 22b, and the pair of connecting pieces 22c are welded and fixed to the shaft 250. As a result, when the connecting member 22 is pressed against both shafts 250, the contact areas of the outer surfaces 27a of both shafts 250 are pressed down by the bottom surface 22b of the connecting member 22, causing the shaft 250 to rotate to a rotation position where the U-shaped portion 252 presses against the wedge-shaped cam 262 and no further rotation is possible (a state in which the shaft 250 has rotated to a position where it can push and rotate the wedge-shaped cam 262, which serves as a locking member). Therefore, simply by welding the pair of connecting pieces 22c of the connecting member 22 pressed as described above to both shafts 250, the rotational positions of both shafts 250 can be aligned by welding, thereby improving the synchronization of both reclining units 221a, 221b without making the connecting process complicated.

The characteristic configuration of this embodiment may be applied to the configuration of the second embodiment. That is, in the manufacturing process of welding the connecting member 120 using both support portions 27, as in the second embodiment, the first reclining unit 221a and the second reclining unit 221b are positioned so that the rotation centers of their respective shafts are located on the predetermined rotation axis L. The pair of connecting pieces 22c are welded and fixed to the shaft with the connecting member 120 pressed against the shaft so that the embossments 121 press and rotate the outer surface 27a. As a result, when the connecting member 120 is pressed against the shaft, the embossments 121 on the bottom surface 22b press down on the contact portion of the outer surface 27a of the shaft, causing the shaft to rotate to a rotation position where the U-shaped portion 252 presses against the wedge-shaped cam 262 and then to a state where it cannot rotate further. Therefore, simply by welding the pair of connecting pieces 22c of the connecting member 120 pressed against the shaft as described above, the rotational positions of both shafts can be aligned and fixed by welding, improving the synchronization of both reclining units 221a, 221b without making the connecting process complicated.

Other Embodiments
The present invention is not limited to the above-described embodiments, and may be embodied as follows, for example.
(1) The elongated connecting member 22 is not limited to being formed in a substantially U-shape by the main body 22a and the pair of connecting pieces 22c, but may be formed, for example, so that only the ends welded to the shafts 24a, 24b are provided with the pair of connecting pieces 22c, and the central portion has another shape (for example, a flat plate shape or a square ring shape consisting of only the main body 22a). The connecting member 120 can be formed in a similar manner.

(2) The present invention is not limited to being applied to a vehicle seat 10 having a reclining device 20 in which the base plate 30 is attached to the lower bracket 11a and the gear plate 40 is attached to the upper bracket 12a, but may also be applied to a vehicle seat having a reclining device in which the base plate is attached to the upper bracket 12a and the gear plate is attached to the lower bracket 11a.

(3) In the first embodiment and the like, instead of the reclining units 21a and 21b (excluding the shafts 24a and 24b), a reclining unit that controls the meshing between the external teeth of a lock gear, which is guided radially slidably relative to a base plate, and the internal teeth of a gear plate by rotating a cam, may be used, such as the reclining units disclosed in Japanese Patent Application Laid-Open No. 2018-114095 and Japanese Patent Application Laid-Open No. 2013-163474, which have the same basic configuration. The same applies to the second embodiment and the like.

(4) In the third embodiment and the like, instead of reclining units 221a and 221b excluding the shaft, a reclining unit such as the reclining unit disclosed in Japanese Patent Application Laid-Open No. 2021-146833 or the reclining unit disclosed in Japanese Patent Application Laid-Open No. 2021-83659, which have the same basic configuration, may be used. In this unit, two plates are eccentrically positioned to mesh some of the external and internal teeth, restricting the relative rotation of the two plates when the shaft does not rotate, and rotating a cam by rotating the shaft to control the two plates so that they can rotate relative to each other.

10... Vehicle seat 11... Seat cushion 12... Seat back 20... Reclining device 21a, 221a... First reclining unit (one of the reclining units)
21b, 221b...second reclining unit (the other reclining unit)
22... Connecting member 22a... Main body portion 22b... Bottom surface 22c... Connecting piece 24a, 24b, 110a, 110b, 250... Shaft 26... Fitting portion 27... Support portion 27a... Outer surface (opposing surface)
30...base plate (first plate)
40...Gear plate (second plate)
41... Internal teeth 61... First lock gear 61a... External teeth 62... Second lock gear 62a... External teeth 70... Cam (locking member)
80: Urging member 90: Cam lever 120: Connecting member 121: Embossment (protrusion)
230...External gear (first plate)
240...Internal gear (second plate)
262...Wedge-shaped cam (locking member)
L…Rotation axis line

Claims (4)

a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A vehicle seat comprising:
the connecting member includes a main body having a flat bottom surface and a pair of connecting pieces connected to the main body at both ends thereof so as to face each other via the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed, facing each other in an inclined state with a planar opposing surface partially contacting the bottom surface of the connecting member;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
The vehicle seat is characterized in that, when fixed by welding, the shaft is positioned so that the rotation center of the shaft is located on a predetermined rotation axis and the opposing surface is at a predetermined inclination angle with respect to the bottom surface. a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A vehicle seat comprising:
the connecting member includes a main body portion having a flat bottom surface, a pair of connecting pieces connected to the main body portion at both ends thereof so as to face each other via the bottom surface, and a protrusion provided on the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed in a state in which the planar opposing surfaces of the shaft face the bottom surface of the connecting member with a predetermined gap therebetween;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
When fixed by welding, the shaft is arranged so that its rotation center is located on a predetermined rotation axis line,
The vehicle seat, wherein the protrusion is provided on the bottom surface at a position that pushes and rotates the opposing surface when the seat is welded and fixed. a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A method for manufacturing a vehicle seat comprising:
the connecting member includes a main body having a flat bottom surface and a pair of connecting pieces connected to the main body at both ends thereof so as to face each other via the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed, facing each other in an inclined state with a planar opposing surface partially contacting the bottom surface of the connecting member;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
a step of positioning the one reclining unit and the other reclining unit so that the rotation centers of the respective shafts are positioned on a predetermined rotation axis line;
pressing the connecting member against the shaft so that the opposing surface is inclined at a predetermined angle with respect to the bottom surface;
welding and fixing the pair of connecting pieces to the shaft while pressing the connecting member against the shaft;
A method for manufacturing a vehicle seat, comprising: a seat cushion and a seat back;
one reclining unit and another reclining unit that control tilting of the seat back relative to the seat cushion;
a long connecting member for connecting the one reclining unit and the other reclining unit so as to rotate synchronously;
A method for manufacturing a vehicle seat comprising:
the connecting member includes a main body portion having a flat bottom surface, a pair of connecting pieces connected to the main body portion at both ends thereof so as to face each other via the bottom surface, and a protrusion provided on the bottom surface,
The one reclining unit and the other reclining unit are
a shaft to which the pair of connecting pieces are welded and fixed in a state in which the planar opposing surfaces of the shaft face the bottom surface of the connecting member with a predetermined gap therebetween;
A locking member;
a first plate attached to the seat cushion;
a second plate attached to the seat back;
Each equipped with
The locking member is pushed and rotated by the rotating shaft, and the first plate and the second plate, which are in a relatively rotatable state, rotate relatively around the rotation center of the shaft in response to the rotation of the shaft, thereby tilting the seat back relative to the seat cushion,
a step of positioning the one reclining unit and the other reclining unit so that the rotation centers of the respective shafts are positioned on a predetermined rotation axis line;
pressing the coupling member against the shaft so that the protrusion presses against the opposing surface;
welding and fixing the pair of connecting pieces to the shaft while pressing the connecting member against the shaft;
A method for manufacturing a vehicle seat, comprising: