JPWO2016042631A1 - Vehicle seat and method for manufacturing frame structure of vehicle seat - Google Patents

Abstract

The vehicle seat (1) includes a seat cushion (3), an inner rear cross member (24), a seat back (4R), and an inner seat back frame structure (20R). The seat back frame structure consists of a lower cross member (30M) on the lower frame, a tower member (33) integrated with the lower cross member on the lower side of the left frame, a right frame and an upper frame, and a left end on the tower member. And an inverted L-shaped elbow member (34) fixed to the tip. A first belt tool (16) is fixed to the rear cross member, and a second belt tool (47) is fixed in the vicinity of the fixing portion between the tower member and the elbow member. A first part (AR1) including an integrated part of the lower cross member and the tower member, a second part (AR2) of the elbow member, and a third part (AR3) including a fixing part of the first belt device of the rear cross member; At least one of them is highly rigid.

Description

  The present invention relates to a vehicle seat and a method for manufacturing a frame structure of a vehicle seat.

Patent Document 1 describes a technique for increasing the strength of a frame structure serving as a skeleton in a single-seat vehicle seat by heat treatment.
This technology is a state in which a plurality of frame members made of general steel are integrally framed, and any one of the heat treatments such as induction hardening, liquid carburizing, and gas carburizing is applied to the frame portion requiring strength or the entire frame. To obtain the same strength as high-strength steel.

JP 2011-235789 A

Vehicle seats include so-called split seats that can be seated on three people and are divided into two-seat and one-seat seats, such as those often used for seats in front of a car's luggage compartment. . The split seat is divided into, for example, 6: 4 in the width direction of the vehicle, and is mounted in a car room.
The wide side (60% side) sheet for two persons in this split type sheet usually occupies half or more of the width of the room. Therefore, the frame structure used as the skeleton of the wide side seat is wider and larger in mass than the single seat frame structure.
In such a frame structure, the part where the safety belt holder is fixed has higher rigidity than other parts so as not to cause local excessive deformation in the event of a collision or the like. However, it has not been considered to increase the rigidity of the frame structure of the wide side seat.
Accordingly, in order to improve the strength and rigidity of the entire frame structure, the number of frame points is increased, and the entire frame structure is heat-treated.
As a result, the efficiency of manufacturing work is reduced and the manufacturing cost is increased, and improvement is desired.

  In order to meet such demands, an object of the present invention is to provide a vehicle seat and a vehicle seat frame structure manufacturing method that improve the efficiency of manufacturing operations and reduce the manufacturing cost.

According to the first aspect of the present invention, the seat cushion, the seat back having a smaller width in the left-right direction than the seat cushion and capable of rotating in the front-rear direction, and extending in the left-right direction inside the seat cushion. A rear cross member housed in a seat frame, a rectangular frame-like seat back frame structure housed inside the seat back, and a right side serving as a lower frame of the seat back frame structure and extending in the left-right direction A seat back lower cross member, a tower member whose lower part is integrated with the seat back lower cross member as a left frame of the seat back frame structure, and a left end as a right frame and an upper frame of the seat back frame structure An inverted L-shaped seat back elbow member fixed to the tip of the tower member and a rear cross member Comprises a first safety belt holder, and a second safety belt holder which is attached to the fixed portion near said and the tower member seatback elbow member, the,
A portion where the seat back lower cross member and the tower member are integrated, or a first portion which is at least a portion of the tower member; and the right frame and the upper frame of the seat back elbow member At least one of the second part straddling the part and the third part including the part to which the first safety belt holder of the rear cross member is attached is the first part. There is provided a vehicle seat characterized in that it is formed to have higher rigidity than parts other than the third part.

According to the second aspect of the present invention, a frame structure provided as a skeleton on a vehicle seat having a seat cushion and a seat back having a smaller lateral width than the seat cushion and capable of pivoting back and forth. A vehicle frame manufacturing method for a vehicle seat for manufacturing a body,
The frame structure includes a rear cross member that is housed inside the seat cushion and extends in the left-right direction, a rectangular frame-like seat back frame structure housed inside the seat back, and a right side that is the seat back. A seat back lower cross member which is a lower frame of the frame structure and extends in the left-right direction; a tower member whose lower part is integrated with the seat back lower cross member as a left frame of the seat back frame structure; An inverted L-shaped seat back elbow member whose left end is fixed to the tip of the tower member as a right frame and an upper frame of the seat back frame structure, and a first safety belt attached to the rear cross member A second safety member attached in the vicinity of a fixing portion between the holding member and the tower member and the seat back elbow member. An assembly step of assembling by welding so as to have a belt holder, and a portion where the seat back lower cross member and the tower member are integrated by the assembly step, or at least a portion of the tower member A first portion, a second portion straddling the right frame and the upper frame in the seat back elbow member, and a portion to which the first safety belt holder is attached in the rear cross member. A heat treatment step in which at least one of the third parts is preheated before the assembly step so as to have higher rigidity than parts other than the first part to the third part. And a method for manufacturing a frame structure for a vehicle seat.

  According to the vehicle seat and the frame structure manufacturing method for a vehicle seat of the present invention, work efficiency in manufacturing is improved and manufacturing cost is reduced.

FIG. 1 is a perspective view showing a seat group ST including a vehicle seat according to the embodiment. FIG. 2 is a perspective view showing the frame structure 20 used in the vehicle seat 1 of the first embodiment. FIG. 3 is a front view showing the frame structure 20. FIG. 4 is a schematic left side view showing the frame structure 20. FIG. 5 is a perspective view for explaining a state in which the safety belts 12 and 18 are attached to the frame structure 20. FIG. 6 is a perspective view illustrating a frame structure 201 used for the vehicle seat 101 according to the second embodiment. FIG. 7 is a perspective view showing a frame structure 202 used in the vehicle seat 102 of the third embodiment.

  A vehicle seat and a frame structure manufacturing method of a vehicle seat according to an embodiment will be described with reference to FIGS. 1 to 7, the traveling direction of the vehicle is assumed to be the front, and the front, rear, left, right, and top directions are indicated as FR, RR, LH, RH, UP, and LWR.

Example 1
The vehicle seat 1 of the first embodiment (hereinafter also simply referred to as the seat 1) and the frame structure 20 that is the skeleton of the seat 1 will be described with reference to FIGS.
First, FIG. 1 is a perspective view showing a sheet group ST of 6: 4 divided sheets mounted on a vehicle. The seat group ST includes a 60% side seat 1 arranged on the right side of the vehicle room to which the frame structure 20 is applied, and a 40% side seat 2 arranged in parallel independently on the left side of the seat 1. Including.

The seat 1 to which the frame structure 20 is applied includes a seat cushion 3, a seat back 4R, and a seat back 4C, and a right seat 1R and a center seat 1C that can seat two persons are formed. ing.
That is, the right seat 1R is formed including a seat cushion portion 3R that is a right portion of the seat cushion 3 and a seat back 4R.
The center seat 1C is formed including a seat cushion portion 3C, which is a left portion of the seat cushion 3, and a seat back 4C.
A headrest 5R is attached to the upper end of the seat back 4R, and a headrest 5C is attached to the upper end of the seat back 4C.

The seat 1 is engaged with a pair of rails 51L and 51R installed on the vehicle floor 50 and extending in parallel in the front-rear direction so as to be movable in the front-rear direction.
A pair of recesses 6 extending in the front-rear direction is formed on the lower surface of the sheet 1. Rails 51L and 51R enter the pair of recesses 6, respectively.

In the center seat 1C, a belt hole P1 is provided in the left rear portion of the seat cushion portion 3C. A buckle belt 11a is pulled out from the belt hole P1. A buckle 11 is attached to the tip of the buckle belt 11a.
A belt hole P2 is provided in the right rear portion of the seat cushion portion 3C. A belt hole P3 is provided in the upper left part of the seat back 4R.
The safety belt 12 is pulled out from the belt hole P2 and pulled in from the belt hole P3. The safety belt 12 is pulled by a safety belt retractor 46 (see FIG. 2; hereinafter also referred to as the retractor 46), which will be described later, so as to be drawn into the belt hole P3 through a belt guide 47 (see FIG. 2) in a normal state. Yes.

The safety belt 12 is inserted into a through hole 13a provided in the tongue plate 13, and a movement restricting member (not shown) through which the tongue plate 13 cannot pass is attached at a predetermined position.
As a result, the tongue plate 13 is restricted from moving from a predetermined position (generally shown in FIG. 1) to the belt hole P2 side and is movable to the belt hole P3 side.
The tongue plate 13 can be engaged with the buckle 11 while pulling the safety belt 12 from the belt hole P3 against the pulling force of the retractor 46 by manually pulling the tongue plate 13 toward the buckle 11.
The safety belt 12 with the tongue plate 13 engaged with the buckle 11 is shown by a two-dot chain line in FIG.
The body of the passenger seated on the central seat 1C is stably held by the safety belt 12.

A buckle belt 14a is pulled out together with the safety belt 12 from the belt hole P2. A buckle 14 is attached to the tip of the buckle belt 14a.
The buckle 14 engages with a tongue plate 19 (see FIG. 5) of a safety belt 18 (see FIG. 5) pulled out from the vehicle body side.
The safety belt 18 stably holds the occupant's body seated in the right seat 1R.

The seat 1 includes a frame structure 20 shown in FIG. 2 as a skeleton, and a cushion portion 7 (see FIG. 4) that wraps the frame structure 20.
As for the cushion part 7, the external shape is shown with the dashed-two dotted line and the continuous line in FIG. 4, and an internal structure is shown in part cross section.
Specifically, the cushion part 7 has an exterior part 7a and a flexible part 7b wrapped in the exterior part 7a, and is formed so as to cover almost the entire frame structure 20.
The exterior part 7a is formed of, for example, a polyurethane sheet. The flexible part 7b is formed so as to have flexibility by using polyurethane foam.

Next, details of the frame structure 20 will be described with reference mainly to FIGS.
The frame structure 20 includes a cushion frame structure 20 </ b> A that is a skeleton of the seat cushion 3. Further, the frame structure 20 includes a seat back frame structure 20R serving as a skeleton of the seat back 4R, a seat back frame structure 20C serving as a skeleton of the seat back 4C, and a base frame structure 20D fixed to the vehicle body. ,have.
The base frame structure 20D supports the cushion frame structure 20A and the seat back frame structure 20R.

First, the base frame structure 20 </ b> D is disposed below the frame structure 20 and includes legs 22 </ b> L and 22 </ b> R, a front cross member 23, and a rear cross member 24.
The legs 22L and 22R have engagement blocks 21L and 21R that engage with the rails 51L and 51R, respectively.
The legs 22L and 22R are connected by a tubular front cross member 23 extending in the left-right direction on the front side, and connected by a tubular rear cross member 24 extending in the left-right direction on the rear side.
The outer diameter of the rear cross member 24 is larger than the outer diameter of the front cross member 23.

A seat cushion frame 26 is attached above the front cross member 23 via a seat flip-up device 25 attached to the front cross member 23. The seat cushion frame 26 is formed in a frame shape that is long in the left-right direction by a tube.
In the frame of the seat cushion frame 26, three spring bars 27 extending in the front-rear direction are attached.
The cushion frame structure 20 </ b> A that includes the seat cushion frame 26 and the spring bar 27 and serves as a skeleton of the seat cushion 3 is configured.
The cushioning property of the seat cushion portion 3 </ b> R is satisfactorily exhibited by the flexibility of the flexible portion 7 b of the cushion portion 7 and the bending of the spring bar 27.

Next, the seat back frame structure 20R will be described.
A right reclining device 28 is attached to the right end of the rear cross member 24, and a left reclining device 29 having an arm plate 29a is attached to the left end.
A plate-like side bracket 30 that is thinly formed in the left-right direction is connected to the right reclining device 28 so as to extend obliquely upward and rearward.
A seat back lower cross member 30M extending in the left-right direction is provided between the side bracket 30 and the arm plate 29a.
The seat back lower cross member 30M includes, for example, a tubular out lower cross member 31 and a tubular in lower cross member 32. The seat back lower cross member 30M is arranged in a straight line via a tower member 33.

The tower member 33 is formed in a plate shape having the thickness direction in the left-right direction.
On the lower side of the tower member 33, an out lower cross member 31 and an in lower cross member 32 are connected as a joint with a coaxial core parallel to the rear cross member 24. This connection is performed by welding.
That is, the tower member 33 has a lower portion integrated with the seat back lower cross member 30M.
The upper part of the tower member 33 extends obliquely upward and rearward in the same direction as the side bracket 30. Further, the tower member 33 extends to a position higher than the side bracket 30.

The side bracket 30 and the tip of the tower member 33 are connected by a seat back elbow member 34.
The seat back elbow member 34 is formed by a pipe, and extends along the side bracket 30. The upper portion 34b extends horizontally through a side portion 34a that extends along the side bracket 30 and a corner portion that gently curves to the left at the upper end of the side portion 34a. ,have.
The right side surface of the side portion 34 a is fixed to the left side surface of the side bracket 30 by welding, and the left end portion of the upper portion 34 b is fixed to the tip portion of the tower member 33 by welding.
In addition, a tubular cross pipe 35 is bridged between the longitudinal intermediate portion of the side portion 34a and the longitudinal intermediate portion of the tower member 33 in parallel with the out lower cross member 31, and is fixed by welding.
As a result, the lower lower member 31 as the seat back lower cross member 30M is used as the lower frame, the side portion 34a of the side bracket 30 and the seat back elbow member 34 is used as the right frame, and the upper portion 34b of the seat back elbow member 34 is used as the upper frame. A rectangular frame is formed with the tower member 33 as the left frame. The seat back frame structure 20 </ b> R is configured including the frame, the inner lower member 32 as the seat back lower cross member 30 </ b> M, and the cross pipe 35.

  A pair of headrest holders 8 are attached to the upper portion 34 b of the seat back elbow member 34. A stay (not shown) extending downward from the headrest 5R is inserted into the headrest holder 8. Thereby, the headrest 5R is attached to the seat back 4R.

  The seat back frame structure 20R can be rotated (in the front-rear direction) around the virtual rotation axis Ca extending in the horizontal direction (arrow Da) by the right reclining device 28, and can be seated in a predetermined angle range. It can be locked in any posture.

Next, the seat back frame structure 20C will be described.
The left reclining device 29 provided at the left end of the rear cross member 24 is capable of rotating the arm plate 29a about a rotation axis Ca extending in the horizontal direction (in the front-rear direction).
A central reclining device 41 is fixed to the arm plate 29a. An outer arm 42 extending upward in FIG. 2 is attached to the central reclining device 41.
The outer arm 42 can be rotated around a virtual rotation axis Cb extending horizontally by the central reclining device 41.
The outer arm 42 can be locked in a standing posture (solid line in FIG. 2) and a horizontal posture (see the two-dot chain line in FIG. 2 and FIG. 4) in use.
The seat back 4C is used as an armrest of an occupant seated on the right seat 1R or the seat 2 in a horizontal posture.

A seat back frame 43 formed in a substantially rectangular frame shape by a tube is fixed to the right side surface of the outer arm 42 by welding.
The seat back frame 43 includes a side portion 43a fixed to the outer arm 42, a side portion 43b arranged to face the right side of the side portion 43a, and an upper portion 43c that connects the upper ends of the two side portions 43a and 43b. And a lower portion 43d for connecting the lower ends.
An inner arm 44 is attached to the side portion 43b. The inner arm 44 is engaged with a pin 33a provided on the tower member 33 so as to protrude leftward with the rotation axis Cb as an axis.
Thereby, the seat back frame 43 is supported by the central reclining device 41 and the pin 33a so as to be rotatable around the rotation axis Cb (in the front-rear direction).
The seat back frame structure 20 </ b> C includes the seat back frame 43.

  A pair of headrest holders 9 are attached to the upper portion 43 c of the seat back frame 43. A pair of stays (not shown) extending downward from the headrest 5C are inserted into the headrest holder 9. Thereby, the headrest 5C is attached to the seat back 4C.

Next, a structure for fixing the safety belts 12 and 18 and the buckle belts 11a and 14a described in FIG. 1 to the frame structure 20 will be described with reference mainly to FIG.
FIG. 5 is a diagram for explaining a use state in which the safety belt 12 for the center seat 1C and the safety belt 18 for the right seat 1R are attached to a seated occupant (not shown) with respect to FIG. Some members that are not involved in the explanation are omitted in order to avoid complication of drawing.

One end side of the buckle belt 11a is fixed to the rear side of the leg 22L in the base frame structure 20D. A buckle 11 is attached to the other end side of the buckle belt 11a.
The other end side of the buckle belt 14a to which the buckle 14 is attached to one end side is fixed to the central portion in the left-right direction of the rear cross member 24.
In addition, a safety belt anchor 16 is fixed by welding to a portion closest to the left side of the portion where the buckle belt 14a is fixed.

A retractable bracket 45 is fixed to the left end portion of the cross pipe 35 in the seat back frame structure 20 </ b> R by welding in a posture along the tower member 33.
The retractor (safety belt retractor) 46 described above is attached to the upper end portion of the retractable bracket 45.
A belt guide 47 is attached to the left end portion of the upper portion 34 b of the seat back elbow member 34.
The belt guide 47 may be provided on the tower member 33 side. That is, the seat back elbow member 34 or the tower member 33 is provided in the vicinity of the fixing portion of both members.

One end side (lower side) of the safety belt 12 is fixed to the safety belt anchor 16 and is drawn out from the belt hole P2 (see FIG. 1).
And in the non-use state shown by the solid line in FIG. 1, it extends upward and is drawn into the inside from the belt hole P3 (see FIG. 1).
In the vicinity of the belt hole P3, the belt guide 47 supports the belt hole P3 so that it can freely enter and exit, and the other end is wound around a retractor 46 that is a winding device.

In addition to the safety belt 12 and the safety belt 18, a plurality of members for fixing a child seat or the like are fixed to the rear cross member 24.
Specifically, as shown in FIG. 2, a left isofix (ISOFIX) anchor 17L is fixed to the rear surface of the rear cross member 24 where the safety belt anchor 16 is fixed by welding. Also, a right isofix (ISOFIX) anchor 17R is fixed to the rear surface in the vicinity of the right reclining device 28 by welding.
A tether anchor 15 is fixed by welding on the right rear side of the rear cross member 24 where the buckle belt 14a is fixed.

In the frame structure 20 described above, the tower member 33 provided at the left end of the seat back frame structure 20R is coupled to a pair of left and right legs 22L and 22R that are members fixed to the floor 50 of the vehicle body. The rear cross member 24 is not directly connected.
That is, the tower member 33 is provided in a disconnected state with respect to the rear cross member 24. The tower member 33 is supported by the rear cross member 24 only via the left reclining device 29 and the right reclining device 28 provided at the left and right ends thereof.
This greatly simplifies the structure of the frame structure 20. Further, the seat back frame structure 20R can be easily attached to the cushion frame structure 20A.
Further, the frame structure 20 has a small number of parts and is lightweight.

  The frame structure 20 is subjected to partial heat treatment at a necessary portion, and necessary and sufficient strength and rigidity are ensured while realizing such a simple lightweight structure. This strength improvement will be described with reference mainly to FIG.

As shown in FIG. 5, the safety belt 12 for the center seat 1 </ b> C is fixed to the safety belt anchor 16 at one end side in a state where the safety belt 12 is used for a passenger. The other end side is inserted into the belt guide 47 through the tongue plate 13 engaged with the buckle 11, and is wound while being pulled by the retractor 46.
The safety belt 18 for the right seat 1R has a lower end fixed to a safety belt anchor (not shown) provided at the lower part of the vehicle body. The upper end side is wound while being pulled by a retractor (not shown) provided on the right side of the room through a tongue plate 19 attached to the buckle 14.

In such a state of use, when a sudden deceleration of the vehicle traveling forward is caused by a forward collision or the like and the feeding of the safety belts 12 and 18 is locked, it corresponds to the inertial force of the occupant with respect to the frame structure 20. A forward force is applied.
Specifically, for the occupant seated in the central seat 1C, forward forces F1 to F3 are applied to the belt guide 47, the buckle 11, and the safety belt anchor 16, respectively. Further, for the occupant seated in the right seat 1R, a forward force F4 is applied to the buckle 14.

The frame structure 20 is configured so that the amount of deformation when it is deformed is sufficiently suppressed so that local deformation due to the applied forces F1 to F4 does not easily occur. Specifically, a specific part of the plurality of members constituting the frame structure 20 has a part of or the entire part made higher in rigidity than the remaining part or other members.
The highly rigid parts are three highly rigid parts AR1 to AR3 described below. The high-rigidity portions AR1 to AR3 are indicated by halftone dots in FIG.
That is, the high rigidity parts AR1 to AR3 are set to have higher rigidity than the other parts.

The high-rigidity part AR <b> 1 is the left side part including the fixing part of the tower member 33 in the out lower cross member 31 and the entire in lower cross member 32.
It is preferable that the right end position (the right end position of the distance La from the tower member 33 in FIG. 1) of the high rigidity portion AR1 is half of the length of the out lower cross member 31 at the maximum. Further, the distance La is 0 (zero), that is, the high-rigidity portion AR1 is not provided in the out lower cross member 31, but is provided only in the in lower cross member 32 which is the left side portion with respect to the tower member 33. Also good.

  The high rigidity part AR2 is a part on the side part 34a side of the entire side part 34a of the seat back elbow member 34 and the upper part 34b. The highly rigid portion AR2 may be set as a portion straddling at least the side portion 34a and the upper portion 34b.

  The high rigidity part AR3 is a central part including the fixing part of the buckle belt 14a and the safety belt anchor 16 in the rear cross member 24. The length of the highly rigid portion AR3 in the left-right direction may be set in the range of 2/5 to 4/5 with respect to the length of the rear cross member 24. Further, it is preferable that the high rigidity portion AR3 includes a fixing portion of the tether anchor 15 and the left isofix anchor 17L which are omitted in FIG.

The high-rigidity parts AR1 to AR3 are high-frequency heating for each member (outer lower member 31, seat back elbow member 34, rear cross member 24, hereinafter also referred to as a member to be highly rigid) formed of general steel. It is denatured and formed with higher rigidity than other parts by partial heat treatment.
As a method other than the high-frequency heating, a general steel pipe is used, and the formation of the highly rigid member shape and the formation of the highly rigid portions AR1 to AR3 by partial heat treatment thereof are performed in one step by a so-called three-dimensional hot bending quenching method. You may go on.
The method of partial heat treatment is not limited to these, and a well-known method can be applied. For example, liquid carburization and gas carburization.

Regardless of which partial heat treatment method is used, it is assumed that the highly rigid member has already been formed with the highly rigid portions AR1 to AR3 in a single member state before being assembled.
Thereafter, the out lower cross member 31 and the seat back elbow member 34 are assembled as the seat back frame structure 20R, and the rear cross member 24 is assembled together with the legs 22L and 22R as the base frame structure 20D.

By providing the high-rigidity portion AR1, it is easy to occur because the out lower cross member 31 is not directly connected to the rear cross member 24. The amount of bending is suppressed. Further, the forward movement and forward deformation of the tower member 33 due to the force F1 are suppressed. This forward movement and forward tilt deformation correspond to bending deformation and twisting deformation of the out lower cross member 31 and the in lower cross member 32, respectively.
In this way, deformation of the seat back 4R is suppressed by suppressing the deformation of the out lower cross member 31 and the in lower cross member 32.

By providing the high-rigidity portion AR2, occurrence of forward tilt deformation of the seat back elbow member 34 and forward tilt deformation of the tower member 33 due to the force F1 and the amount of deformation at the time of the deformation are suppressed. These forward deformations correspond to bending deformation and twisting deformation of the seat back elbow member 34.
In this manner, the deformation of the seat back 4R is suppressed by suppressing the deformation of the seat back elbow member 34.

By providing the high-rigidity portion AR3, the occurrence of the forward convex bending of the rear cross member 24 by the force F3 or the force F4 and the deformation amount when the forward convex bending occurs are suppressed.
By suppressing the forward convex bending deformation of the rear cross member 24 in this manner, the influence of deformation propagation to the seat cushion frame 26 disposed in front of the rear cross member 24 is also suppressed, and the deformation of the seat cushion 3 is suppressed. Is done.

On the other hand, when the vehicle collides from behind with respect to the vehicle, such as a rear-end collision, which is opposite to the frontal collision, a rapid increase in speed occurs in the vehicle. The seat back 4R, the seat back 4C, and the seat cushion 3 are strongly pushed rearward by the inertial force of the seated occupant accompanying the increased speed.
Also in this case, the deformation of the sheet 1 is suppressed by providing the high rigidity portions AR1 to AR3.

  Specifically, by providing the high-rigidity portion AR1, the torsional deformation and the bending deformation are less likely to occur including the portion where the tower member 33 of the out lower cross member 31 is fixed. As a result, the tower member 33 is unlikely to fall backward and move rearward, and the amount of deformation and the amount of movement are suppressed even if they occur temporarily.

  By providing the high-rigidity portion AR2, the seat back elbow member 34 is less likely to bend in the front-rear direction and torsionally deform in the front-rear direction on the tower member 33 side with respect to the portion fixed to the side bracket 30. This makes it difficult for the tower member 33 to fall backward and the seat back elbow member 34 to fall backward, and even if they occur, the amount of deformation is suppressed.

  By providing the highly rigid portion AR3, the rear cross member 24 is less likely to bend toward the rear side. Thereby, even if the seat cushion 3 moves rearward due to the inertial force of the seated occupant, the rear cross member 24 restricts excessive rearward movement of the seat cushion frame 26 serving as the skeleton. Therefore, the seat cushion 3 does not move greatly backward, and the large deformation of the seat 1 is suppressed.

The frame structure 20 does not have to be provided with all of the high-rigidity parts AR1 to AR3, and only needs to be provided with any one part.
For example, in the case of a frame structure having only the highly rigid portion AR1, the highly rigid portion AR2 and the highly rigid portion AR3 have a multiple structure in which the thickness of the corresponding portion is thicker than other portions. A method other than heat treatment, such as increasing the diameter, is applied to achieve high rigidity.

(Example 2)
Next, Example 2 will be described with reference to FIG.
A frame structure 201 is used for the vehicle seat 101 of the second embodiment. The frame structure 201 is different from the frame structure 20 of the first embodiment in that an elbow member 331 as one tower member is used instead of the inner lower member 32 and the tower member 33.

The elbow member 331 functions as a constituent member of the seat back frame structure 201R in the frame structure 201.
The elbow member 331 has a cross portion 331b and a side portion 331c and is formed in an L shape.
Specifically, the right end portion of the cross portion 331b is fixed to the left end portion of the out lower cross member 31 by a fixing portion by welding, and the left end portion is fixed to the arm plate 29a of the left reclining device 29. The side portion 331 c is a portion extending upward from the fixed portion of the out lower cross member 31, and the upper end portion is welded and fixed to the left end portion of the upper portion 34 b in the seat back elbow member 34.
A pin 331a corresponding to the pin 33a is provided at a lower portion of the side portion 331c.

The elbow member 331 is formed of a general steel pipe, and before being assembled as the seat back frame structure 201R, for example, the entire unit is heat-treated as a highly rigid portion AR4 (dots given in FIG. 6). The highly rigid portion AR4 is made more rigid than a general steel pipe portion or member (for example, the out lower cross member 31).
The highly rigid part AR4 is a part straddling at least the cross part 331b and the side part 331c, and may extend over the whole as described above.

By using the elbow member 331 formed with the highly rigid portion AR4, the number of parts is reduced and the structure is simplified. While the effect is obtained, the elbow member 331 as a whole is a highly rigid portion AR4.
As a result, the elbow member 331 is unlikely to undergo bending deformation and torsional deformation due to the force F1 (see FIG. 5) applied to the belt guide 47. In addition, the amount of deformation when each deformation occurs is suppressed to be small.
Therefore, deformation of the frame structure 201 is suppressed, and deformation of the seat back using the frame structure 201 is suppressed.

(Example 3)
Next, Example 3 will be described with reference to FIG.
A frame structure 202 is used for the vehicle seat 102 of the third embodiment. The frame structure 202 differs from the frame structure 20 of the first embodiment in that a tower pipe 332 is used instead of the tower member 33 as a tower member.

The tower pipe 332 functions as a constituent member of the seat back frame structure 202R in the frame structure 202.
The tower pipe 332 is formed in a straight tube shape, and its upper end is welded and fixed to the left end of the upper portion 34b of the seat back elbow member 34. The lower end portion is a plate-like joint portion 332b that is crushed in the left-right direction. The joint portion 332b includes a right-side outer lower cross member 31 and a left-side inner lower member that constitute the seat back lower cross member 30M. The cross member 32 is connected and fixed by welding.
That is, the tower pipe 332 has a lower portion integrated with the seat back lower cross member 30M.
A pin 332a corresponding to the pin 33a is provided in the vicinity of the lower joint 332b.

Before the tower pipe 332 is formed from a general steel pipe and is assembled as the seat back frame structure 202R, a portion excluding the lowermost portion including the joint portion 332b and the vicinity thereof is a highly rigid portion AR5 (in FIG. 7, a halftone dot). Heat treatment). The high-rigidity portion AR5 is made more rigid than the outer lower cross member 31 and the inner lower cross member 32 that are general steel pipes as they are.
The highly rigid portion AR5 is set as a portion including the upper side of the tower pipe 332. The lower end may be at least on the lower side of the longitudinal center position of the tower pipe 332. The whole site | part except the junction part 332b may be sufficient.

By using the tower pipe 332 formed with the highly rigid portion AR5, bending deformation of the tower pipe 332 due to the force F1 (see FIG. 5) applied to the belt guide 47 hardly occurs. Further, the amount of deformation when bending deformation occurs is suppressed small.
Therefore, the deformation of the frame structure 202 is suppressed, and the deformation of the seat back using the frame structure 202 is suppressed.

  Of course, in the frame structure 201 and the frame structure 202, similarly to the frame structure 20, the highly rigid portions AR1 and AR2 may be formed.

According to the first to third embodiments described in detail above, various effects can be obtained.
According to the first embodiment, the middle part of the cushion frame structure 20A of the seat cushion 3 does not have a frame extending in the front-rear direction corresponding to a lean reinforcement frame for ensuring strength. Thereby, the frame structure 20 is lightweight.
Further, a large thickness of the cushion portion 7 of the seat cushion 3 can be ensured. Thereby, the cushioning property of the seat 1 is improved.
These effects are also obtained in the second and third embodiments.

According to the above-described first to third embodiments, it is necessary to improve rigidity and strength without performing heat treatment for increasing the strength of the frame structure on the entire frame structure 20, 201, 202 after assembly. This is done before assembling the parts. As a result, the work efficiency of assembly does not decrease.
Further, even if a failure occurs in the heat treatment, only the member itself becomes defective, and the assembled frame structures 20, 201, 202 do not become defective. Thereby, in the manufacture of the frame structures 20, 201, 202, the yield does not decrease.
In addition, since the frame structures 20, 201, 202 are made highly rigid only at necessary portions, the safety belts 12, 18 with respect to the frame structures 20, 201, 202 when an impact is applied to the vehicle. Therefore, local excessive deformation due to the force applied from the frame is suppressed, and the deformation is averaged over the entire frame structure. Thereby, excessive deformation of the seats 1, 101, 102 is suppressed, and the influence of the deformation on the seated occupant is effectively suppressed.
In addition, by using a member that forms the high-rigidity portions AR1 to AR3 as a pipe material, a so-called three-dimensional hot bending quenching method can be applied. As a result, shape formation and heat treatment of a desired portion can be performed in one step, and the optimum shape and optimum partial rigidity of the vehicle seat frame structure can be easily obtained at a high level.

The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present invention.
In the first and third embodiments, the seat back lower cross member 30M may be formed as a single straight pipe.
The seat 1 is not limited to one that can be seated by two people.
The vehicle is not limited to an automobile, and may be a moving body that moves an occupant in a seated state, such as an aircraft, a ship, and a railcar.

  INDUSTRIAL APPLICABILITY The present invention can be used for a seat mounted on a vehicle (automobile, aircraft, ship, railway vehicle, etc.) that moves an occupant in a sitting state.

Claims (12)

Seat cushions,
A seat back having a smaller width in the left-right direction than the seat cushion and capable of rotating back and forth;
A rear cross member housed extending in the left-right direction inside the seat cushion;
A rectangular frame-like seat back frame structure housed inside the seat back;
A seat back lower cross member whose right side is a lower frame of the seat back frame structure and extends in the left-right direction;
A tower member in which a lower part is integrated with the seat back lower cross member as a left frame of the seat back frame structure;
An inverted L-shaped seat back elbow member whose left end is fixed to the tip of the tower member as a right frame and an upper frame of the seat back frame structure;
A first safety belt holder attached to the rear cross member;
A second safety belt holder attached in the vicinity of a fixed portion between the tower member and the seat back elbow member;
With
A portion where the seat back lower cross member and the tower member are integrated, or a first portion which is at least a portion of the tower member; and the right frame and the upper frame of the seat back elbow member At least one of the second part straddling the part and the third part including the part to which the first safety belt holder of the rear cross member is attached is the first part. A vehicle seat characterized by being formed with higher rigidity than a portion other than the third portion. The tower member is formed in a plate shape having a thickness in the left-right direction and is fixed to an intermediate portion of the seat back lower cross member,
The vehicle seat according to claim 1, wherein the first part is a part including the intermediate part in the seat back lower cross member. The tower member has a side portion serving as the left frame and a cross portion extending leftward from a lower end portion of the side portion, and is formed in an L-shaped tube. The left end of the lower cross member is connected and fixed,
The vehicle seat according to claim 1, wherein the first portion is a portion straddling at least the side portion and the cross portion in the tower member. The tower member is formed in a straight tube shape, and a lower part is fixed to an intermediate part of the seat back lower cross member as a left frame of the seat back frame structure,
The vehicle seat according to claim 1, wherein the first part is a part including an upper side of the tower member. The seat back lower cross member is composed of a left side in lower cross member and a right side out lower cross member,
The vehicle seat according to claim 2 or 4, wherein the in lower cross member and the out lower cross member are connected and fixed at the intermediate portion via the tower member.   The vehicle seat according to any one of claims 1 to 5, wherein the rear cross member and the seat back elbow member are tubular. A frame structure for a vehicle seat for manufacturing a frame structure provided as a skeleton on a vehicle seat having a seat cushion and a seat back having a smaller lateral width than the seat cushion and capable of pivoting back and forth. A manufacturing method comprising:
The frame structure;
A rear cross member housed in the seat cushion and extending in the left-right direction;
A rectangular frame-like seat back frame structure housed inside the seat back;
A seat back lower cross member whose right side is a lower frame of the seat back frame structure and extends in the left-right direction;
A tower member in which a lower part is integrated with the seat back lower cross member as a left frame of the seat back frame structure;
An inverted L-shaped seat back elbow member whose left end is fixed to the tip of the tower member as a right frame and an upper frame of the seat back frame structure;
A first safety belt holder attached to the rear cross member;
A second safety belt holder attached in the vicinity of a fixed portion between the tower member and the seat back elbow member;
An assembly step of assembling by welding to have
A portion where the seat back lower cross member and the tower member are integrated by the assembling step, or a first portion which is at least a portion of the tower member, and the right frame at the seat back elbow member And at least one part of the second part straddling the part to be the upper frame and the third part including the part to which the first safety belt holder in the rear cross member is attached, A heat treatment step in which heat treatment is performed in advance before the assembly step so that rigidity is higher than portions other than the first portion to the third portion;
A method of manufacturing a frame structure for a vehicle seat, comprising: The tower member is formed in a plate shape having a thickness in the left-right direction and fixed to an intermediate portion of the seat back lower cross member in the assembly step,
8. The method of manufacturing a frame structure for a vehicle seat according to claim 7, wherein the first part is a part including the intermediate part in the seat back lower cross member. The tower member is formed in an L-shaped tube having a side portion serving as the left frame and a cross portion extending leftward from a lower end portion of the side portion, and the tower member is formed in the right portion of the cross portion in the assembly step. Connect and fix the left end of the seat back lower cross member,
8. The method of manufacturing a frame structure for a vehicle seat according to claim 7, wherein the first part is a part straddling the side part and the cross part in the tower member. The tower member is formed in a straight tube shape, and a lower part is fixed to an intermediate part of the seat back lower cross member as a left frame of the seat back frame structure in the assembly step,
8. The vehicle seat frame structure manufacturing method according to claim 7, wherein the first part is a part including an upper side of the tower member. The seat back lower cross member is composed of a left side in lower cross member and a right side out lower cross member,
11. The vehicle seat frame structure manufacturing method according to claim 8, wherein, in the assembling step, the in lower cross member and the out lower cross member are connected and fixed via the tower member. .   The frame structure manufacturing method for a vehicle seat according to any one of claims 7 to 11, wherein the rear cross member and the seat back elbow member are tubular.

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