JP7735211B2 - Seat back frame and vehicle seat - Google Patents

Description

The present invention relates to a vehicle seat, and more particularly to a seat back frame.

In the vehicle seat described in Patent Document 1 below, a back frame disposed within the seat back has a pair of left and right side frames and an upper frame spanning the upper ends of the left and right side frames. A retractor for the seat belt device is attached to this back frame. The seat belt retracted by this retractor is wound around a belt guide (belt anchor bracket) disposed at the shoulder of the seat back and fixed to the upper end of the back frame.

Japanese Patent Application Laid-Open No. 2020-199923

In the above prior art, when a vehicle crashes, the excessive load from the occupant, who tends to move forward in the seat due to inertia, acts on the belt anchor bracket via the seat belt, making it difficult to ensure the strength of the belt anchor bracket.

In consideration of the above, the present invention aims to provide a seat back frame and vehicle seat that makes it easy to ensure the strength of the belt anchor bracket.

The seatback frame of the first aspect comprises a frame main body having left and right side frames and an upper frame spanning between the upper ends of the left and right side frames, to which a retractor of a seat belt device is attached; left and right legs fixed to the upper frame, an upper wall spanning between the upper ends of the left and right legs facing the upper end of one of the left and right side frames from above the seat back, and a belt anchor bracket having a winding portion around which the seat belt to be retracted by the retractor is wound; and an upward extension portion is formed at the upper end of one of the side frames, which protrudes toward the upper side of the seat back and is further forward than the fastening portions of the left and right legs to the upper frame, and which faces the underside of the upper wall portion from below the seat back.

In the first embodiment of the seatback frame, the frame main body has left and right side frames and an upper frame spanning the upper ends of the left and right side frames. A retractor of the seat belt device is attached to this frame main body. The left and right legs of a belt anchor bracket are fixed to the upper frame of the frame main body. The belt anchor bracket has an upper wall portion spanning the upper ends of the left and right legs and a winding portion around which the seat belt to be retracted by the retractor is wound, and the upper wall portion faces the upper end of one of the left and right side frames from above the seat back.

According to this aspect, an upward extension is formed on the upper end of the one side frame, protruding upward toward the seat back and further forward than the fixed portions of the left and right legs of the belt anchor bracket to the upper frame. This upward extension faces the underside of the upper wall portion of the belt anchor bracket from the underside of the seat back. Therefore, when excessive load from the seat belt acts on the belt anchor bracket, the underside of the upper wall portion of the belt anchor bracket comes into contact with the upward extension, transmitting the load to the one side frame. This makes it easy to ensure the strength of the belt anchor bracket.

The seat back frame of the second aspect is the same as that of the first aspect, except that the upward extension faces the underside of the upper wall portion with a gap therebetween.

In the second embodiment of the seat back frame, the upward extension formed on the upper end of one of the side frames of the frame main body faces the underside of the upper wall of the belt anchor bracket with a gap between them. This prevents the upward extension from accidentally interfering with the underside of the upper wall of the belt anchor bracket due to manufacturing variations when fixing the left and right legs of the belt anchor bracket to the upper frame of the frame main body.

The seatback frame of the third aspect is the seatback frame of the first or second aspect, wherein the one side frame has a side wall portion whose thickness direction is the left-right direction of the seatback and a front flange portion extending from the front end of the side wall portion inward in the left-right direction of the seatback, and the upward extension portion is formed by a part of the side wall portion and a part of the front flange portion.

In the seatback frame of the third aspect, one side frame of the frame main body has a side wall portion whose thickness direction is the left-right direction of the seatback, and a front flange portion that extends from the front end of the side wall portion inward in the left-right direction of the seatback. The upward extension portion formed at the upper end of one side frame is composed of a part of the side wall portion and a part of the front flange portion. This makes it easier to ensure the strength of the upward extension portion compared to, for example, when the upward extension portion is composed of only a part of the side wall portion or only a part of the front flange portion.

The seat back frame of the fourth aspect is any one of the first to third aspects, in which the belt anchor bracket comprises a fixed bracket having the left and right leg portions and the upper wall portion, and a wrapping bracket fixed to the upper surface of the upper wall portion to form the wrapping portion.

In the seat back frame of the fourth aspect, the left and right legs of the fixed bracket are fixed to the upper frame of the frame body, and the seat belt is wound around a wrapping bracket fixed to the upper surface of the upper wall of the fixed bracket. In this way, the belt anchor bracket is composed of two parts, the fixed bracket and the wrapping bracket, which allows for greater freedom in designing the shape of each part.

The seatback frame of the fifth aspect is any one of the first to fourth aspects, in which a nut, onto which a bolt that fastens the wrapping bracket to the upper wall portion is threaded, is welded to the underside of the upper wall portion, and the upward extension portion faces the nut from the front of the seatback.

In the seatback frame of the fifth aspect, a nut is welded to the underside of the upper wall portion of the fixed bracket. A bolt that fastens the wraparound bracket to the upper wall portion of the fixed bracket is threaded into this nut. An upward extension formed on the upper end of one of the side frames faces the nut from the front of the seatback. By arranging the nut and upward extension side by side in the fore-and-aft direction of the seatback in this way, it is easy to ensure space for the upward extension and nut.

The seatback frame of the sixth aspect is any one of the first to fifth aspects, in which the upper frame is inserted into a through-hole formed in the upper end of one of the side frames, and the left and right legs of the belt anchor bracket are separated and fixed to the upper frame on both sides of the upper end of the one of the side frames in the left-right direction of the seatback.

In the sixth aspect of the seatback frame, the upper frame of the frame body is inserted into a through-hole formed in the upper end of one of the side frames. The left and right legs of the belt anchor bracket are separated and fixed to the upper frame on both sides of the seat back in the left-right direction relative to the upper end of one of the side frames. As a result, when the upper wall portion spanning between the upper ends of the left and right legs hits the upward extension of one of the side frames due to the load from the belt anchor bracket, the belt anchor bracket is supported in a balanced manner by the upper frame and one of the side frames.

The vehicle seat of the seventh aspect includes a seat cushion on which a vehicle occupant sits, a seat back whose framework is formed by the seat back frame of any one of the first to sixth aspects and which supports the back of the occupant, and a seat belt device in which a seat belt, which is wound around a retractor attached to the seat back frame, is wound around a winding portion of a belt anchor bracket provided on the seat back frame.

In the seventh aspect of the vehicle seat, a vehicle occupant sits on a seat cushion, with the occupant's back supported by the seat back. A retractor of a seat belt device is attached to a seat back frame that forms the framework of the seat back. The seat belt that is wound around the retractor is wound around a winding portion of a belt anchor bracket provided on the seat back frame. Because the seat back frame is any one of the first to sixth aspects, the aforementioned functions and effects are achieved.

As explained above, the seatback frame and vehicle seat according to the present invention make it easy to ensure the strength of the belt anchor bracket.

1 is a perspective view showing a vehicle seat according to an embodiment; 1 is a perspective view showing a configuration around a belt anchor bracket in a seat back frame provided in a vehicle seat according to an embodiment. FIG. FIG. 3 is a first perspective view showing a portion of the configuration shown in FIG. 2; FIG. 3 is a second perspective view of a portion of the configuration shown in FIG. 2 . FIG. 3 is a front view showing a part of the configuration shown in FIG. 2 . FIG. 3 is a side view showing a portion of the configuration shown in FIG. 2.

A vehicle seat 10 according to one embodiment of the present invention will now be described with reference to Figures 1 to 6. Note that in each figure, some reference numerals may be omitted to make the drawings easier to understand. Furthermore, the arrows FR, LH, RH, and UP shown as appropriate in each figure indicate the front, left, right, and top of the vehicle seat 10, respectively.

As shown in FIG. 1, a vehicle seat 10 according to an embodiment of the present invention includes a seat cushion 12 on which a vehicle occupant sits, and a seat back 14 that supports the occupant's back. This vehicle seat 10 is, for example, the driver's seat of a right-hand drive vehicle. If this vehicle seat 10 is, for example, the driver's seat of a left-hand drive vehicle, the configuration will be symmetrical to that of this embodiment.

The framework of the seat back 14 is formed by a seat back frame 20 according to an embodiment of the present invention. When the seat back 14 is in the upright position shown in FIG. 1, the front-rear, left-right, top-bottom directions of the seat back 14 coincide with the front-rear, left-right, top-bottom directions of the vehicle seat 10. Hereinafter, when the front-rear, left-right, top-bottom directions are used in explanations, they refer to directions relative to the seat back 14 unless otherwise specified.

The seatback frame 20 comprises a frame main body 22 and a belt anchor bracket 40. The frame main body 22 has a pair of left and right side frames 24, an upper frame 26 connecting the upper ends of the left and right side frames 24 in the left-right direction, a lower frame 28 connecting the lower ends of the left and right side frames 24 in the left-right direction, a pair of upper and lower intermediate frames 30, 32 connecting the vertical intermediate portions of the left and right side frames 24 in the left-right direction, and a headrest stay 33 fixed to the left-right intermediate portion of the upper frame 26.

The left and right side frames 24 are elongated plates with the vertical direction as the longitudinal direction and the horizontal direction as the plate thickness direction. The upper frame 26, lower frame 28, and upper and lower intermediate frames 30, 32 are cylindrical with the horizontal direction as the axial direction. The left and right side frames 24 are made of, for example, press-formed metal plate material, while the upper frame 26, lower frame 28, and upper and lower intermediate frames 30, 32 are made of, for example, metal pipe material.

The lower ends of the left and right side frames 24 are connected to the rear ends of the seat cushion frame, which forms the framework of the seat cushion 12, via a well-known reclining mechanism. This allows the seat back frame 20, i.e., the seat back 14, to be reclined (tilted) relative to the cushion frame, i.e., the seat cushion.

A retractor 36 of a three-point seat belt device 34 is attached to the upper and lower intermediate frames 30, 32. One longitudinal end of a seat belt (webbing) 38 of the seat belt device 34 is secured to the retractor 36's winding shaft, and the other longitudinal end is secured to an anchor member provided on one of the left and right sides of the seat cushion 12 (here, the right side). The longitudinal middle portion of the seat belt 38 is looped around a belt anchor bracket 40 provided on one of the left and right shoulders of the seat back 14. A tongue plate (not shown) is attached to the longitudinal middle portion of the seat belt 38 between the anchor member and the belt anchor bracket 40. This tongue plate is connectable to a buckle 42 provided on the other left and right side of the seat cushion 12 (here, the left side).

In the seat belt device 34 configured as described above, an occupant seated on the seat cushion 12 of the vehicle seat 10 fastens the seat belt 38 by connecting the tongue plate to the buckle 42. In this fastened state, the portion of the seat belt 38 from the belt anchor bracket 40 to the tongue plate serves as a shoulder belt that restrains the occupant's upper body, and the portion of the seat belt 38 from the tongue plate to the anchor member serves as a lap belt that restrains the occupant's waist.

As shown in Figure 2, the belt anchor bracket 40 is disposed above one of the left and right side frames 24 (here, the right side frame 24). As an example, the belt anchor bracket 40 is composed of a fixed bracket 46 and a wrap-around bracket 50.

As shown in Figures 2 to 6, the fixed bracket 46 is made of, for example, a press-formed metal plate. This fixed bracket 46 has a pair of left and right legs 46A facing each other in the left-right direction, and an upper wall 46B spanning the upper ends of the left and right legs 46A, forming a roughly inverted U-shape when viewed from the front to back. The left and right legs 46A are fixed to the upper frame 26 of the frame main body 22.

Specifically, in this embodiment, the right end of the upper frame 26 is inserted into a through-hole 25 formed in the upper end of the right side frame 24, and is fixed to the right side frame 24 by welding or other means. The left and right legs 46A of the fixing bracket 46 are arranged on either side of the upper end of the right side frame 24. A roughly semicircular cutout 47 (reference numeral omitted except in Figure 6) that is open toward the front of the seat is formed in the lower part of each of the left and right legs 46A. The upper frame 26 is fitted into each cutout 47 from the front side of the seat. The edges of the left and right legs 46A are fixed to the upper frame 26 by welding or other means. An upper wall 46B spanning the upper ends of the left and right legs 46A faces the upper end of the right side frame 24 from above.

The wrapping bracket 50, as an example, is composed of a bracket main body 52 and multiple (here, three) wires 54, 56, and 58, forming a wrapping portion around which the seat belt 38 is wrapped. The bracket main body 52 is made, for example, of a press-formed metal plate. The bracket main body 52 has a pair of left and right side walls 52A facing each other in the left-right direction and a lower wall 52B spanning the lower ends of the left and right side walls 52A, forming a roughly U-shape when viewed from the front to the rear. The three wires 54, 56, and 58 are made, for example, of bent metal wire and spanning between the left and right side walls 52A. Two of the three wires 54, 56, and 58 are arranged side by side in the front-to-rear direction below the remaining wire 54, and are inclined downward as they extend outward in the left-to-right direction. The middle longitudinal portion of the seat belt 38 is wound around these two wires 56, 58.

The lower wall portion 52B of the bracket main body 52 is superimposed on the upper surface of the upper wall portion 46B of the fixed bracket 46. The lower wall portion 52B and the upper wall portion 46B each have a plurality of bolt holes (two in this case) not shown. A bolt 60 (see Figure 2) is inserted into each of these bolt holes from above. Each bolt 60 is threaded into a plurality of nuts (two in this case) welded to the underside of the upper wall portion 46B. This fastens and secures the bracket main body 52, i.e., the wrap-around bracket 50, to the upper wall portion 46B of the fixed bracket 46.

The upper wall portion 46B of the fixed bracket 46 is positioned above the right side frame 24 (hereinafter sometimes referred to as the "right side frame 24"). An upward extension portion 24E protruding upward is formed at the front portion of the upper end of the right side frame 24. The rear portion of the upper end of the right side frame 24, where this upper extension portion 24E is not formed, is recessed downward relative to the front portion of the upper end of the right side frame 24. This upper extension portion 24E is positioned forward of the attachment portions (edges of the notches 47) of the left and right legs 46A of the fixed bracket 46 to the upper frame 26, and faces the front portion of the lower surface of the upper wall portion 46B from below, with a gap 64 (reference number omitted except in Figure 5). The vertical dimension of this gap 64 is set to, for example, approximately several millimeters.

As shown in FIG. 4, the right side frame 24, which has an upper extension 24E, has a side wall 24A whose thickness is in the left-right direction, a front flange 24B extending inward in the left-right direction from the front end of the side wall 24A, and a rear flange 24C extending inward in the left-right direction from the rear end of the side wall 24A. The upper extension 24E is formed by a portion of the side wall 24A and a portion of the front flange 24B, and is generally L-shaped when viewed from the top. As shown in FIGS. 2 to 5, this upper extension 24E faces from the front one of the two nuts 62 fixed to the underside of the upper wall 46B. In other words, the space behind the upper extension 24E is used to arrange one of the nuts 62.

(Action and effect)
Next, the operation and effects of this embodiment will be described.

In this embodiment, the seatback frame 20, which forms the framework of the seatback 14 of the vehicle seat 10, includes a frame main body 22 and a belt anchor bracket 40. The frame main body 22 has left and right side frames 24 and an upper frame 26 spanning between the upper ends of the left and right side frames 24. A retractor 36 of a seat belt device 34 is attached to the frame main body 22. Left and right legs 46A of a belt anchor bracket 40 are fixed to the upper frame 26 of the frame main body 22. The belt anchor bracket 40 has an upper wall portion 46B spanning between the upper ends of the left and right legs 46A and a winding portion (winding bracket 50) around which the seat belt 38 wound around the retractor 36 is wound. The upper wall portion 46B faces the upper end of the right side frame 24, one of the left and right side frames 24, from above.

An upward extension 24E is formed at the upper end of the right side frame 24, protruding upward and forward of the fixed portions of the left and right legs 46A of the belt anchor bracket 40 to the upper frame 26. This upward extension 24E faces the lower surface of the upper wall portion 46B of the belt anchor bracket 40 from below. Therefore, if excessive load from the seat belt 38 acts on the belt anchor bracket 40 during a vehicle collision, the lower surface of the upper wall portion 46B of the belt anchor bracket 40 will contact the upper extension 24E, transmitting the load to the right side frame 24. This makes it easier to ensure the strength of the belt anchor bracket 40. As a result, measures such as increasing the thickness of the left and right legs 46A or the upper wall portion 46B to ensure the strength of the belt anchor bracket 40 are no longer necessary, allowing for a lighter and more cost-effective belt anchor bracket 40.

In addition, in this embodiment, the above-mentioned upward extension 24E faces the underside of the upper wall portion 46B of the belt anchor bracket 40 with a gap 64 between them. Therefore, when fixing the left and right legs 46A of the belt anchor bracket 40 to the upper frame 26 of the frame main body 22, the upward extension 24E can be prevented from inadvertently interfering with the underside of the upper wall portion 46B of the belt anchor bracket 40 due to manufacturing variations. This makes it easier to fix the belt anchor bracket 40 to the upper frame 26.

In addition, in this embodiment, the right side frame 24 of the frame main body 22 has a side wall portion 24A whose thickness direction is in the left-right direction, and a front flange portion 24B that extends inward in the left-right direction from the front end of the side wall portion 24A. The upward extension portion 24E formed at the upper end of the right side frame 24 is composed of a part of the side wall portion 24A and a part of the front flange portion 24B, and is generally L-shaped when viewed from the top-down direction. This makes it easier to ensure the strength of the upward extension portion 24E compared to, for example, when the upward extension portion 24E is composed of only a part of the side wall portion 24A or only a part of the front flange portion 24B.

In addition, in this embodiment, the belt anchor bracket 40 includes a fixed bracket 46 having the left and right leg portions 46A and the upper wall portion 46B, and a wrapping bracket 50 that is fixed to the upper surface of the upper wall portion 46B and forms a wrapping portion for the seat belt 38. As such, because the belt anchor bracket 40 is composed of two parts, the fixed bracket 46 and the wrapping bracket 50, there is a high degree of freedom in designing the shape of each part.

In addition, in this embodiment, two nuts 62 are welded to the underside of the upper wall portion 46B of the fixed bracket 46. Bolts 60 that fasten the wrap bracket 50 to the upper wall portion 46B of the fixed bracket 46 are threaded into these nuts 62. The upper extension portion 24E formed on the upper end of the right side frame 24 faces one of the nuts 62 from the front. In this way, by arranging the nuts 62 and the upper extension portion 24E side by side in the front-to-rear direction, it is easy to ensure space for the nuts 62 and the upper extension portion 24E.

In addition, in this embodiment, the upper frame 26 of the frame main body 22 is inserted into a through-hole 25 formed in the upper end of the right side frame 24. The left and right legs 46A of the belt anchor bracket 40 are separated into two on either side of the seat back in the left-right direction relative to the upper end of the right side frame 24 and fixed to the upper frame 26, respectively. As a result, when the upper wall portion 46B spanning between the upper ends of the left and right legs 46A hits the upward extension portion 24E of the right side frame 24 due to a load from the belt anchor bracket 40, the belt anchor bracket 40 is supported in a balanced manner by the upper frame 26 and the right side frame 24.

In the above embodiment, the upper frame 26 is inserted into the through-hole 25 formed in the upper end of the right side frame 24 (one of the side frames), but this is not limiting, and the configuration of the joint between one of the side frames and the upper frame can be modified as appropriate.

In addition, in the above embodiment, the wrapping bracket 50 is fixed to the fixed bracket 46 using bolts 60 and nuts 62, but this is not limited to this. For example, the wrapping bracket may be fixed to the fixed bracket by welding.

In addition, in the above embodiment, the belt anchor bracket 40 is described as being composed of two parts: the fixed bracket 46 and the wrapping bracket 50. However, this is not limited to this, and the belt anchor bracket may also be composed of a single part.

In addition, in the above embodiment, the upward extension 24E is described as being formed by a portion of the side wall 24A and a portion of the front flange 24B of the right side frame 24 (one of the side frames), but this is not limiting, and the upward extension may be formed by only a portion of the side wall or only a portion of the front flange of one of the side frames.

In addition, in the above embodiment, the upper extension 24E faces the underside of the upper wall portion 46B of the belt anchor bracket 40 with a gap 64 between them, but this is not limited to this, and the configuration may also be such that no gap is formed between the upper extension and the upper wall portion of the belt anchor bracket.

The present invention can be modified and implemented in various ways without departing from its spirit. It goes without saying that the scope of the present invention is not limited to the above-described embodiment.

REFERENCE SIGNS LIST 10 Vehicle seat 12 Seat cushion 14 Seat back 20 Seat back frame 22 Frame body 24 Side frame 24A Side wall portion 24B Front flange portion 24E Upper extension portion 25 Through hole 26 Upper frame 34 Seat belt device 36 Retractor 38 Seat belt 40 Belt anchor bracket 46 Fixing bracket 46A Leg portion 46B Upper wall portion 50 Wrap-around bracket 60 Bolt 62 Nut 64 Gap

Claims (8)

a frame main body having left and right side frames and an upper frame spanning upper ends of the left and right side frames, the frame main body having a retractor of a seat belt device attached thereto;
a belt anchor bracket having left and right leg portions fixed to the upper frame, an upper wall portion spanning between upper ends of the left and right leg portions facing an upper end portion of one of the left and right side frames from above the seat back, and having a winding portion around which the seat belt to be wound by the retractor is wound;
Equipped with
an upper end portion of one of the side frames is formed with an upward extension portion that protrudes toward the upper side of the seat back and is located forward of the seat back relative to the fixed portions of the left and right legs to the upper frame, and that faces the lower surface of the upper wall portion from the lower side of the seat back;
The seat back frame has the upward extension portion disposed above the seat back relative to the upper frame . a frame main body having left and right side frames and an upper frame spanning upper ends of the left and right side frames, the frame main body having a retractor of a seat belt device attached thereto;
a belt anchor bracket having left and right leg portions fixed to the upper frame, an upper wall portion spanning between upper ends of the left and right leg portions facing an upper end portion of one of the left and right side frames from above the seat back, and having a winding portion around which the seat belt to be wound by the retractor is wound;
Equipped with
an upper end portion of one of the side frames is formed with an upward extension portion that protrudes toward the upper side of the seat back and is located forward of the seat back relative to the fixed portions of the left and right legs to the upper frame, and that faces the lower surface of the upper wall portion from the lower side of the seat back;
A seat back frame configured so that when an excessive load from the seat belt acts on the belt anchor bracket, the lower surface of the upper wall portion of the belt anchor bracket comes into contact with the upward extension portion . 3. The seat back frame according to claim 1 , wherein the upper extension portion faces the lower surface of the upper wall portion with a gap therebetween . the one side frame has a side wall portion whose thickness direction is the left-right direction of the seat back, and a front flange portion extending inward in the left-right direction of the seat back from a front end portion of the side wall portion,
4. The seat back frame according to claim 1 , wherein the upward extension portion is formed by a part of the side wall portion and a part of the front flange portion . The belt anchor bracket is
a fixed bracket having the left and right legs and the upper wall;
a wrapping bracket fixed to an upper surface of the upper wall portion to form the wrapping portion;
The seat back frame according to any one of claims 1 to 4, comprising : A nut having a bolt threaded thereon is welded to the underside of the upper wall portion, the bolt fastening the wrapping bracket to the upper wall portion,
The seat back frame according to any one of claims 1 to 4 , wherein the upward extension portion faces the nut from the front of the seat back . The upper frame is inserted into a through hole formed in an upper end portion of the one side frame,
The seat back frame according to any one of claims 1 to 6, wherein the left and right legs of the belt anchor bracket are separated into two on either side of the seat back in the left-right direction relative to the upper end of one of the side frames and fixed to the upper frame, respectively. a seat cushion on which a vehicle occupant sits;
a seat back whose framework is constituted by the seat back frame according to any one of claims 1 to 7 and which supports the back of the occupant;
a seat belt device in which a seat belt, which is wound around a retractor attached to the seat back frame, is wound around a winding portion of a belt anchor bracket provided on the seat back frame;
A vehicle seat comprising: