JP2001058530A - Seat back for automobile use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable holding cervix of a crewman surely by that a head rest support member that supports a headrest is rotated back and forth against a side frame, with an upper end of the side frame as the center. SOLUTION: A forward impact load is added, and next, the secondary impact load is added to a crewman toward the rear side. Since an impact value accompanied by a secondary collision is more than the load at which a return spring 12 for active headrest begins to be stretched, the return spring 12 for active headrest begins to be stretched by the fact that a pressure part 8 is shifted to the rear side, and a headrest holder bracket 9 begins to rotate as the pressure part 8 is shifted, and a headrest support member 7 that supports the headrest holder bracket 9 rotates forward, with a shoulder bolt 5 and a bush 6 as the center. This leads to control rotation of a headrest 3 to forward through a stay bolt 13, thus the protection of head of a crewman can be surely held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle seat back, and more particularly to a vehicle seat back structure for protecting a cervical vertebra of a vehicle occupant when the vehicle is hit by another vehicle.

[0002]

2. Description of the Related Art A conventional seat back of an automobile is provided with a horizontal frame member having a rotating hinge at a front side of an upper end portion of a side frame, as shown in, for example, Japanese Patent Application Laid-Open No. Hei 10-119196, and is collided. Is provided with the pressure receiving part.

[0003] Therefore, for example, when the own vehicle is collided, an impact load (primary collision) is applied to the seat back toward the front side first, and then the reaction load (secondary collision) by the occupant is applied. Acts toward the back. That is, the load acts on the pressure receiving portion. At this time, the pressure receiving portion moves rearward, whereby the horizontal frame rotates forward around the front rotating hinge, and the headrest supported by the horizontal frame moves to a portion corresponding to the occupant's head. Thus, the headrest operates in a direction approaching the occupant's head.

Therefore, even if the seatback flexes rearward due to the reaction load of the vehicle occupant when the vehicle collides, the pressure load causes the pressure receiving portion to instantaneously make the headrest by the principle of leverage, thereby causing the head of the occupant to return. , The head of the occupant is securely received by the headrest, and the cervical vertebra of the occupant is protected.

[0005]

However, in such a conventional technique, since the rotating hinge is provided on the front side, when the seat back is pressed from the front side, the rotating hinge can be caught there as foreign matter. Will be.
In addition, since the horizontal frame member is inclined forward, it is likely to interfere with the occupant's shoulder, and the movement of the horizontal frame member may be stopped by the shoulder or the like.Therefore, the amount of forward movement of the headrest needs to be improved. ing.

The present invention has been made by paying attention to such a conventional technique, and the center of rotation when the headrest moves to the front side does not give the occupant a foreign-body sensation. An object of the present invention is to provide an automobile seat back for the purpose of allowing the headrest to move forward by an amount corresponding to the pressing.

[0007]

According to a first aspect of the present invention, there is provided a seat back frame having at least side frames on both sides, and a headrest support rotatably mounted between upper ends of the side frames so as to be rotatable back and forth. Components,
A pressure-receiving portion supported by the headrest support member and arranged at a position where it can receive an impact load accompanying a rear-end collision;
At least a headrest supported movably up and down by a headrest holder bracket supported by the headrest support member.

According to the first aspect of the present invention, since the headrest supporting member supporting the headrest rotates back and forth with respect to the side frame, the center of rotation is in the side frame, so that no foreign object feeling is given. In addition, when the load due to the secondary collision of the occupant is applied to the pressure receiving part, it rotates around the upper end of the side frame, so it is in a position that does not easily interfere with the occupant's shoulder, and the headrest moves forward by that much It is possible to reliably hold the occupant's neck.

According to a second aspect of the present invention, there is provided the automobile seat back according to the first aspect, wherein the pressure receiving portion and the headrest holder bracket are integrally formed.

According to the second aspect of the present invention, since it is possible to mold with one member, the manufacturing cost can be reduced, and an inexpensive seat back can be provided.

According to a third aspect of the present invention, in the vehicle seat back according to the first or second aspect, the pressure receiving portion and the headrest holder bracket are formed separately.

According to the third aspect of the present invention, since the pressure receiving portion and the headrest holder bracket are formed separately, the headrest holder bracket has:
Although it is necessary to have a size sufficient to support the headrest, it does not need to be extended to the pressure receiving portion, so that it is light in weight and easy to manufacture, so that the manufacturing cost can be greatly reduced. Also,
The pressure receiving portion only needs to be able to withstand the load caused by the secondary collision by the occupant.

According to a fourth aspect of the present invention, there is provided the automobile seat back according to any one of the first to third aspects, wherein an upper cross member is fixed between upper ends of the side frames. It is erected.

According to the fourth aspect of the present invention, since the side frame and the upper cross member form a square, the strength of the seat back is remarkably improved, and the headrest supporting member for supporting the pressure receiving portion for receiving the secondary collision is provided. There is no trouble such as deformation.

According to a fifth aspect of the present invention, there is provided the vehicle seat back according to any one of the first to fourth aspects, wherein the pressure receiving portion is constantly urged to the front side and the seat pressure is reduced. An urging means which does not extend but can be extended only by an impact load accompanying a rear-end collision is interposed.

According to the fifth aspect of the present invention, the pressure receiving portion is always urged to the front side and does not extend under a seating load, but interposes an urging means which can be extended only by an impact load accompanying a rear-end collision. Therefore, when the occupant is normally seated or relaxed, the urging means does not extend in response to the backrest load of the occupant's back, and the back can be held. In addition, when a load due to a secondary collision due to a rear-end collision is applied, the urging means can be extended, so that there is no hindrance to the movement of the pressure receiving portion, and it is possible to move reliably.

According to a sixth aspect of the present invention, there is provided the vehicle seat back according to any one of the first to fifth aspects, wherein the headrest support member is biased rearward on the upper cross member. Then, the headrest support member is brought into contact with the headrest support member to form a first stopper surface for preventing rotation of the headrest support member.

According to the sixth aspect of the present invention, when the occupant is seated or relaxed in a normal state, the first cross member of the upper cross member corresponds to the backrest load by the back of the occupant.
Since the stopper surface contacts the headrest support member, the headrest support member does not rotate, and the position of the headrest is maintained.

According to a seventh aspect of the present invention, there is provided the vehicle seat back according to any one of the first to sixth aspects, wherein the upper cross member is provided with the headrest supporting member rotated forward. The headrest support member is in contact with the headrest support member to form a second stopper surface for preventing rotation of the headrest support member.

According to the seventh aspect of the present invention, even if the headrest is rotated forward by the secondary collision and the occupant's neck can be protected, the headrest interferes with the second stopper surface of the upper cross member. As a result, the headrest does not further rotate forward, so that a problem that the headrest abnormally rotates forward can be prevented.

According to an eighth aspect of the present invention, there is provided the automobile seat back according to any one of the first to seventh aspects, wherein the headrest holder bracket and the pressure receiving portion are substantially U-shaped when viewed from the front. Make

According to the eighth aspect of the present invention, the pressure receiving portion corresponding to the occupant's back and the headrest holder bracket, which are positions where the impact load accompanying the rear-end collision can be received, are substantially U-shaped in front view. Therefore, there is no projection, and an operating plate or the like for receiving pressure is unnecessary, and the cost is reduced.

According to a ninth aspect of the present invention, there is provided the automobile seat back according to any one of the first to seventh aspects, wherein the headrest holder bracket and the pressure receiving portion are substantially L-shaped in a front view. Make

According to the ninth aspect of the present invention, the pressure receiving portion corresponding to the occupant's back portion, which is a position where the impact load accompanying the rear-end collision can be received, and the headrest holder bracket are substantially L-shaped when viewed from the front. Therefore, since there is no projection, an operating plate or the like for receiving pressure is not necessary, which is inexpensive and has only one headrest holder bracket.

According to a tenth aspect of the present invention, there is provided the automobile seat back according to any one of the first to third aspects, wherein the pressure receiving portion has a substantially I-shape in a front view. Eggplant

According to the tenth aspect of the present invention, since the pressure receiving portion corresponding to the occupant's back portion, which is a position where the impact load accompanying the rear-end collision can be received, is substantially I-shaped when viewed from the front, the protrusion is formed. It does not exist, and the operating plate for receiving pressure becomes unnecessary,
Since it is inexpensive and has only one pressure receiving section, it is possible to significantly reduce the weight.

According to an eleventh aspect of the present invention, there is provided the vehicle seat back according to any one of the first to ninth aspects, wherein the headrest holder bracket avoids a portion corresponding to an occupant's shoulder and holds the headrest. The pressure receiving portion is formed of a straight portion that allows the stay to move up and down.

According to the eleventh aspect of the present invention, since the linear portion does not interfere with the shoulder of the occupant, the frontrest of the headrest rotates more. Also, since the pressure receiving part is thin in front and back,
Interference with the rear passengers' knees and the like is prevented. Further, the pressure receiving portion is more likely to receive the load due to the secondary collision of the occupant.

[0029]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Note that FR is described as a front side, RR is a rear side, UP is an upper side, and LWR is a lower side.

FIGS. 1 to 4 show an embodiment of the present invention. Reference numeral 1 denotes an automobile seat back, and reference numeral 3 denotes a headrest.

The seat back 1 has a seat back frame 4 having at least two iron-made side frames 2 and 2 on both sides, and a rear RR of upper ends 2a and 2a of the side frames 2 and 2 of the seat back frame 4. A headrest support member 7 made of an iron plate and rotatably mounted on the front and rear FR and RR by a stepped bolt 5 and a bush 6 for absorbing rubbing noise and impact during rotation, and a headrest support member 7 described later. The upper end 14a of the straight portion 14 is welded GW
And a pressure receiving portion 8 arranged at a position where a secondary impact load accompanying a rear-end collision can be received. In this embodiment, the headrest holder bracket 9 and the pressure receiving portion 8 are formed integrally and have a U-shape in a front view.

The seat back frame 4 includes the side frames 2 and 2 and an upper end 2 of the side frame 2.
an upper cross member 10 extending substantially horizontally between the front sides FR of the first and second side frames 2a and 2a, and a lower cross member 11 extending substantially horizontally at the lower ends 2b and 2b of the side frames 2. The frame 2, the upper cross member 10 and the lower cross member 11 are mutually supported by welding. Between the side frames 2 and 2,
A return spring 12 for the active headrest, which does not bend during normal use, which is a "biasing means", and a ride comfort spring 35, which can bend under the load during normal use, are provided. , 17. The return spring 12 for the active headrest and the spring 35 for the ride comfort are both S
Although it is shaped like a letter, the spring constants differ greatly as described above.

As shown in FIG. 3, a part of the return spring 12 for the active headrest is directly engaged with the pressure receiving portion 8, so that the pressure receiving portion 8 is constantly urged toward the front side FR. The active headrest return spring 12 has a "spring force" that does not expand under a sitting load of an occupant (not shown) but can expand only under a secondary impact load accompanying a rear-end collision.

As shown in FIG. 4, the headrest support member 7 has an upper surface portion 7a extending vertically left and right having upper and lower through holes 19 through which the headrest holder bracket 9 is inserted, and the upper surface portion 7a. A rear surface portion 7b hanging down from the rear end of the headrest holder bracket 9 along the rear side RR of the headrest holder bracket 9 is formed by being bent at a right angle. A weld GW is supported between the front FR surface of the rear surface portion 7b and the headrest holder bracket 9. At the lower end of the rear surface portion 7b, a second stopper portion 7c is formed which is further suspended downward at a position separated from a first stopper surface 10a of the upper cross member 10 described later. At both left and right end portions of the rear surface portion 7b, there are provided intervening portions 7e, 7e formed by being bent toward the front side FR.

A first stopper 7d is formed at the front end of the upper surface 7a. The first stopper 7d and the second stopper 7c have the first stopper surface 10a of the upper cross member 10 and the first stopper 7d. Second stopper surface 10 described later
b, a buffer member 1 for preventing metal contact
8 and 18 are respectively arranged.

As shown in FIG. 4, the upper cross member 10 has a U-shaped cross section having a front side FR closed and a rear side RR opened.
a is hung down along the rear side RR of the headrest holder bracket 9. When the occupant leans on the seat back 1 and applies a load to the headrest 3, the first stopper surface 10a comes into pressure contact with the second stopper portion 7c of the headrest support member 7 via the cushioning member 18, and the headrest support member 7 is prevented from rotating. Further, when the headrest support member 7 rotates to the front side FR by means described later, the first stopper portion 7d of the headrest support member 7 abuts via the cushioning member 18 to move the headrest support member 7 forward. A second stopper surface 10b for preventing rotation is formed. Note that reference numeral 18 in FIG.
0b, but in a state where no secondary collision load is applied, the state shown in FIG. 4, that is, the first stopper portion 7d of the headrest support member 7, the second stopper surface 10b Are separated from each other even with the buffer member 18 interposed therebetween.

The headrest holder bracket 9 includes:
Straight portions 14, 14 facing slightly upward from the upper surface portion 7 a of the headrest support member 7 and roughly hanging down
And curved portions 14a, 14a bent slightly forward from the straight portions 14, 14. The straight part 1
4, a synthetic resin headrest holder 16 is provided.
The stay 13 of the headrest 3 is mounted on the headrest holder 16 so as to be vertically movable. In addition, the straight portions 14, 14 and the curved portion 14
The rear part of the boundary part between a and 14a has a bent part 20 which is bent in the shape of a "ku" on the front side in a side view shown in FIG. 4, and the bent part 20 is as shown in FIG. In addition, the inner surface of the bent portion 20 is a curved surface having a radius of 20 mm, which is formed so as not to interfere with the lower end portion 13a of the stay 13 of the headrest 3.

The straight portions 14, 14 are vertically arranged side by side in a right and left direction when viewed from the front, and the holding position of the straight portions 14, 14 is at least a shoulder of an AF05% tile mannequin (SAE) in a front view. It is arranged on the center side from the point. It is located on the center side from the shoulder point of the AF05% tile mannequin (SAE), which means that the straight portions 14, 14 are located inside the shoulder point of most occupants of adult physique in the left and right direction. So, when your car was hit,
Even if the load from the front FR of the seat back frame 4 by the occupant, that is, the occupant is pressed against the seat back 1 from the front FR, the shoulder point of the occupant does not interfere with the linear portions 14.

The pressure receiving portion 8 is installed at a position near the back of an occupant (not shown), and is formed to be flat toward the front side FR and thinly crushed into the front and rear FRs and RRs, so that the pressure receiving portion 8 is vertically arranged. It has a predetermined width.

The stay 13 of the headrest 3 is formed at a predetermined position so as to avoid a portion corresponding to a shoulder (not shown) of an occupant, and is formed to be inclined toward the front side FR.

Next, the operation according to this embodiment will be described.

When the occupant is seated on a seat cushion composed of the seat back 1 and a seat cushion (not shown) and the driver does not lean against the back of the seat back 1, the head of the occupant and the headrest 3 may not move. There is a gap between them, and a gap is also formed between the occupant's back and the pressure receiving portion 8. However, a pad and a skin member (not shown) are interposed between the back of the occupant and the pressure receiving portion 8. When the occupant leans against the seat back 1 in a relaxed state when seated, the load applied from the back of the occupant can be moved to the rear side RR by bending of the pad, so that the occupant's back can be softly received. You can do it. Therefore, the seating feeling is good. Of course, no load is applied to the pressure receiving portion 8.

In this state, the own vehicle is collided, and an impact load is first applied to the front side FR.
A load moved to R, that is, a secondary impact load is applied. Since the impact value due to the secondary collision is equal to or greater than the load at which the return spring 12 for the active headrest starts to expand, the return spring 12 for the active headrest expands by moving the pressure receiving portion 8 to the rear side RR. , The headrest holder bracket 9 starts rotating by the movement of the pressure receiving portion 8, and the headrest support member 7 supporting the headrest holder bracket 9 rotates to the front FR around the stepped bolt 5 and the bush 6. In this way, the headrest 3 is controlled to rotate to the front side FR via the stay 13, so that the occupant's head can be reliably held and the neck can be protected.

Further, since the center of rotation of the headrest 3 is located on the side of the interposed portion 7e provided on the side frames 2 and 2, even if the stepped bolt 5 is provided, it does not give a foreign object feeling. In addition, when a load due to a secondary collision of the occupant is applied to the pressure receiving portion 8, the side frame 2, 2 rotates about the upper end portions 2a, 2a. As a result, the headrest 3 can move to the front side FR, and the occupant's neck can be reliably held.

Since the shoulder point of the occupant is at least the shoulder point of the AF05% tile mannequin, the pad (not shown) does not bite into the linear portions 14 of the headrest holder bracket 9. For this reason, the linear portions 14 and 14 can smoothly move the rear surface of the pad, and the UP of the pad due to the rotation of the linear portions 14 and 14 is not hindered, and the operation amount of the headrest 3 is sufficiently secured. Can be.

Thus, the back of the occupant is
By moving to the rear side RR, the head of the occupant who is supposed to be left will be surely held by the movement of the headrest 3. Moreover, in this state, since the lower end portions of the linear portions 14 and 14 are bent in the shape of a "ku" toward the front side, when the pressure receiving portion 8 moves to the rear side RR, the pressure receiving portion 8 moves to the rear side RR. And the space with the rear passenger is secured.

The headrest holders 16, 1
6, the stays 13, 13 of the headrest 3 are supported so as to be vertically movable, so that the headrest 3 can be appropriately adjusted to the position of the head of an occupant having a different physique.

Further, since the side frames 2 and 2, the upper cross member 10 and the lower cross member 11 form a square, the strength of the seat back 1 is remarkably improved, and the pressure receiving portion 8 which receives a secondary collision is supported. There is no problem that the headrest support member 7 is deformed.

Further, the pressure receiving portion 8 is always connected to the front FR by a return spring 12 for an active headrest.
It does not extend under the sitting load and can only be extended by the impact load accompanying the rear-end collision, so in the normal occupant's sitting or relaxing state, it corresponds to the backrest load by the back of the occupant. The return spring 12 for the active headrest does not extend, and the spring 3
5, the back of the occupant can be held comfortably.
When a load due to a secondary collision due to a rear-end collision is applied, the return spring 12 for the active headrest
Can be extended, so that there is no hindrance to the movement of the pressure receiving portion 8, and the pressure receiving portion 8 can be reliably moved.

Due to the secondary collision, the headrest 3 is moved to the front side F
Even if the occupant is able to protect the occupant's neck by turning to R, the rotation angle to the front FR can be limited by the stopper surface 10b of the upper cross member 10, so that the front cross FR is abnormally rotated to the front FR. Failure is prevented.

The pressure receiving portion 8 is provided at a position corresponding to the back portion of the occupant where the impact load accompanying the rear-end collision can be received. Since internal projections such as the above do not occur, the operation plate for receiving pressure is unnecessary, and the cost is reduced.

FIG. 5 shows another embodiment of the pressure receiving portion and the headrest holder bracket. That is, reference numeral 21
Is a pressure receiving member of this embodiment, a solid round bar, and a holding member 2 as a hollow head-shaped “headrest holder bracket” for holding the headrest holder 16.
It is separate from 2,22. Upper end 21 of pressure receiving member 21
a and the holding member 22 are supported by welding on the front surface FR of the rear surface portion 7b of the headrest support member 7. Further, a U-shaped pressure receiving portion 23 of the pressure receiving member 21 is provided.
, The return spring 12 for the active headrest is directly engaged.

In the pressure receiving member 21, when the own vehicle is hit by a rear-end and an impact load is applied, the occupant is given a rear RR.
Is applied. Since the impact value associated with the secondary collision is equal to or greater than the load at which the return spring 12 for the active headrest starts to expand, the pressure receiving portion 23 is moved to the rear side RR, so that the return spring 12 for the active headrest expands. , The pressure receiving member 21 formed with the pressure receiving portion 23 starts rotating, and the headrest support member 7 supporting the pressure receiving member 21 is rotated to the front FR around the stepped bolt 5 and the bush 6. Thus, the headrest support member 7
Is rotated, the holding member 22 rotates, and the headrest 3 is moved through the stay 13 supported by the holding member 22.
Is controlled to rotate to the front FR, the head of the occupant can be reliably held, and the neck can be protected. Also, since the lower end portion 13a of the headrest stay 13 is exposed,
The lower end 13a of the stay 13 is thin, so that the amount of protrusion of the headrest 3 to the rear RR when the headrest 3 rotates to the front FR can be small.

FIG. 6 shows still another embodiment of the headrest holder bracket 9. That is, reference numeral 25
Is the headrest holder bracket of this embodiment,
The difference from the headrest holder bracket 9 is that only one straight portion 14 and one curved portion 14a are provided, and the shape is L-shaped with the pressure receiving portion 26 in a front view. Upper end portion 14a of the straight portion 14 of the headrest holder bracket 25
Is a front side F of a rear surface portion 7b of the headrest support member 7.
It is supported by the welding GW on the R surface. The active headrest return spring 12 is directly engaged with the pressure receiving portion 26 as in the first embodiment.

Such a headrest holder bracket 25
In, when the own vehicle is impacted and an impact load is applied,
The occupant is subjected to a load moved to the rear side RR. Since the impact value associated with the secondary collision is equal to or greater than the load at which the return spring 12 for the active headrest starts to expand, the pressure receiving portion 26 is moved to the rear side RR, so that the return spring 12 for the active headrest expands. , The headrest holder bracket 25 starts rotating, and the headrest support member 7 supporting the headrest holder bracket 25 rotates to the front FR around the stepped bolt 5 and the bush 6.
In this manner, the headrest 3 is controlled to rotate to the front FR through the stay 13 inserted and supported via the headrest holder 16 in the hollow portion of the holding member 22 as the right headrest holder bracket 25 and the left “headrest holder bracket” via the headrest holder 16. As a result, the head of the occupant can be securely held, and the neck can be protected.

FIG. 7 shows still another embodiment of the headrest holder bracket 9. That is, reference numeral 30
Is the headrest holder bracket of this embodiment,
The difference from the headrest holder bracket 9 is different from the support means of the stay 13 of the headrest 3.
The point is that it is I-shaped. The upper end 31a of the linear portion 31 of the headrest holder bracket 30 is supported by a welding GW on the front side FR of the rear surface 7b of the headrest support member 7. The return spring 12 for the active headrest is directly engaged with the pressure receiving portion 32 of the headrest holder bracket 31 by the engaging portion 34. Reference numeral 33 denotes a connecting member that connects the upper end portion 31 and the pressure receiving portion 32 that is the lower end portion.

Such a headrest holder bracket 30
In, when the own vehicle is impacted and an impact load is applied,
The occupant is subjected to a load moved to the rear side RR. The impact value associated with such a secondary collision is equal to or greater than the load at which the return spring 12 for the active headrest starts to expand. Therefore, when the pressure receiving portion 32 is moved to the rear side RR, the return spring 12 for the active headrest expands. , The headrest holder bracket 30 starts rotating, and the headrest support member 7 supporting the headrest holder bracket 30 rotates to the front FR around the stepped bolt 5 and the bush 6.
Thus, the headrest 3 is moved to the front side via the stay 13 which is inserted and supported via the headrest holder 16 in the hollow portion of the holding members 22, 22 as “headrest holder brackets” arranged on the left and right sides of the headrest holder bracket 30. Since the rotation is controlled by the FR, the head of the occupant can be reliably held, and the neck can be protected.

In the above description of the operation, it is assumed that the head of the occupant is securely held by the movement of the headrest 3, but the movement of the headrest 3 and the movement of the seat back 1 are relative. Even if the seat back 1 moves to the rear side RR due to the back of the occupant, the headrest 3 does not move with respect to the occupant's head, and is held at that position, thereby protecting the occupant's head. It also includes those described.

In the above description, the return spring for the active headrest was described as an example of the "biasing means". However, the headrest holder brackets 9, 21, 25, and 25 were used.
Needless to say, a coil spring, a torsion coil spring, a torsion bar, or the like may be suspended from the unit 30.

[0060]

According to the first aspect of the present invention, since the headrest supporting member supporting the headrest rotates back and forth with respect to the side frame, the center of rotation is located on the side frame, so that no foreign object feeling is given. In addition, when the load due to the secondary collision of the occupant is applied to the pressure receiving part, it rotates around the upper end of the side frame, so it is in a position that does not easily interfere with the occupant's shoulder, and the headrest moves forward by that much It is possible to reliably hold the occupant's neck.

According to the second aspect of the present invention, since molding can be performed with one member, the manufacturing cost can be reduced, and an inexpensive seat back can be provided.

According to the third aspect of the present invention, since the pressure receiving portion and the headrest holder bracket are formed separately, the headrest holder bracket is
Although it is necessary to have a size sufficient to support the headrest, it does not need to be extended to the pressure receiving portion, so that it is light in weight and easy to manufacture, so that the manufacturing cost can be greatly reduced. Also,
The pressure receiving portion only needs to be able to withstand the load caused by the secondary collision by the occupant.

According to the fourth aspect of the present invention, since the side frame and the upper cross member form a square, the strength of the seat back is remarkably improved, and the headrest supporting member for supporting the pressure receiving portion for receiving the secondary collision is provided. There is no trouble such as deformation.

According to the fifth aspect of the present invention, the pressure receiving portion is always urged to the front side and does not extend under a sitting load, but interposes an urging means which can be extended only by an impact load accompanying a rear-end collision. Therefore, when the occupant is normally seated or relaxed, the urging means does not extend in response to the backrest load of the occupant's back, and the back can be held. In addition, when a load due to a secondary collision due to a rear-end collision is applied, the urging means can be extended, so that there is no hindrance to the movement of the pressure receiving portion, and it is possible to move reliably.

According to the sixth aspect of the present invention, when the occupant is seated or relaxed in a normal state, the first cross member of the upper cross member is corresponding to the backrest load of the occupant's back.
Since the stopper surface contacts the headrest support member, the headrest support member does not rotate, and the position of the headrest is maintained.

According to the seventh aspect of the present invention, even if the headrest rotates forward due to the secondary collision and the occupant's neck can be protected, the headrest interferes with the second stopper surface of the upper cross member. As a result, the headrest does not further rotate forward, so that a problem that the headrest abnormally rotates forward can be prevented.

According to the eighth aspect of the present invention, the pressure receiving portion corresponding to the back portion of the occupant and the headrest holder bracket at the position where the impact load accompanying the rear-end collision can be received are substantially U-shaped in front view. Therefore, there is no projection, and an operating plate or the like for receiving pressure is unnecessary, and the cost is reduced.

According to the ninth aspect of the present invention, the pressure receiving portion corresponding to the occupant's back, which is a position where the impact load accompanying the rear-end collision can be received, and the headrest holder bracket are substantially L-shaped in front view. Therefore, since there is no projection, an operating plate or the like for receiving pressure is not necessary, which is inexpensive and has only one headrest holder bracket.

According to the tenth aspect of the present invention, since the pressure receiving portion corresponding to the occupant's back, which is the position where the impact load accompanying the rear-end collision can be received, is substantially I-shaped when viewed from the front, the protrusion is formed. It does not exist, and the operating plate for receiving pressure becomes unnecessary,
Since it is inexpensive and has only one pressure receiving section, it is possible to significantly reduce the weight.

According to the eleventh aspect of the present invention, since the linear portion does not interfere with the shoulder portion of the occupant, the headrest rotates more forward. Also, since the pressure receiving part is thin in front and back,
Interference with the rear passengers' knees and the like is prevented. Further, the pressure receiving portion is more likely to receive the load due to the secondary collision of the occupant.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing a seat back according to an embodiment of the present invention.

FIG. 2 is a perspective view of FIG. 1;

FIG. 3 is an enlarged perspective view of a main part of FIG. 2;

FIG. 4 is a sectional view taken along the line SA-SA of FIG. 3;

FIG. 5 is a perspective view according to another embodiment of the headrest holder bracket of the present invention.

FIG. 6 is a perspective view of a headrest holder bracket according to still another embodiment of the present invention.

FIG. 7 is a perspective view of a headrest holder bracket according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seat back 2 Side frame 3 Headrest 4 Seatback frame 5,6 Rotating hinge 7 Headrest support member 8,23,26,32 Pressure receiving part 9,25,30 Headrest holder bracket 10 Upper cross member 10a Stopper surface 12 As urging means Return spring for active headrest of 13 Headrest stay 14 Straight part 22 Headrest holder bracket FR Front RR Rear UP Upper LWR Lower

Claims (11)

[Claims] 1. A seat back frame having at least side frames on both sides, a headrest support member erected between the upper ends of the side frames so as to be rotatable back and forth, and supported by the headrest support member. A pressure receiving portion disposed at a position capable of receiving an impact load due to a rear-end collision, and a headrest supported movably up and down by a headrest holder bracket supported by the headrest support member. Characteristic car seat back. 2. The vehicle seat back according to claim 1, wherein the pressure receiving portion and the headrest holder bracket are:
An automobile seat back, which is formed integrally. 3. The vehicle seat back according to claim 1, wherein the pressure receiving portion and the headrest holder bracket are:
An automobile seat back characterized by being formed separately. 4. The vehicle seat back according to claim 1, wherein an upper cross member is fixedly provided between upper ends of the side frames. And car seat back. 5. The vehicle seat back according to claim 1, wherein the pressure receiving portion is always urged forward and does not extend under a seating load, but is involved in a rear-end collision. An automobile seat back comprising an urging means that can be extended only by an impact load. 6. The vehicle seat back according to claim 1, wherein the upper cross member is supported by the headrest support member when the headrest support member is biased rearward. A seat back for an automobile, wherein a first stopper surface is formed in contact with a member to prevent rotation of the headrest support member. 7. The vehicle seat back according to claim 1, wherein the headrest support member contacts the upper cross member when the headrest support member rotates forward. An automobile seat back, wherein a second stopper surface is formed to be in contact with and to prevent rotation of the headrest support member. 8. The vehicle seat back according to claim 1, wherein the headrest holder bracket and the pressure receiving portion define:
An automobile seat back characterized by being substantially U-shaped when viewed from the front. 9. The vehicle seat back according to claim 1, wherein the headrest holder bracket and the pressure receiving portion define:
An automobile seat back characterized by being substantially L-shaped when viewed from the front. 10. The vehicle seat back according to claim 1, wherein the pressure receiving portion is substantially I-shaped when viewed from the front. For seat back. 11. The vehicle seat back according to claim 1, wherein the headrest holder bracket avoids a portion corresponding to a shoulder of an occupant and enables a stay of the headrest to move up and down. A seat back for an automobile, comprising: a straight line portion formed as described above;