JP2012250596A - Seat back board made of resin, and vehicle seat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat back board made of a resin capable of preventing or suppressing local deformation, and a vehicle seat using the same.SOLUTION: In the seat back board 16, a back board part 36 and a pair of right and left frame fixing parts 49 are connected together by a pair of right and left back-and-forth extending parts 50. The back-and-forth extending parts 50 are extendable in a seat back-and-forth direction since waveform part 50A is arranged. Thus, for example, when a load from an occupant is applied to a back spring part 38 and the back board part 36 in rear surface collision of a vehicle, the back-and-forth extending parts 50 are extended in the seat back-and-forth direction, thereby mitigating stress concentration in connection parts C1 and C3. Further, since a load input to a side frame 26 via the frame fixing parts 49, twist deformation of the side frame 26 is suppressed.

Description

  The present invention relates to a resin seat back board and a vehicle seat using the same.

  Patent Document 1 listed below discloses that a spring that is stretched between a pair of left and right side frames provided on a seat back frame is made of resin from the viewpoint of reducing the weight of a vehicle seat.

JP 2004-138156 A

  However, when the member provided on the seat back is made of resin, if stress is concentrated on a part of the member due to a load from the occupant at the time of rear collision of the vehicle (hereinafter referred to as rear collision), local deformation (plasticity) Deformation) may occur.

  In view of the above facts, the present invention has an object to obtain a resin seat back board capable of preventing or suppressing local deformation and a vehicle seat using the same.

  A resin seat backboard according to a first aspect of the present invention includes a backboard portion disposed on a back side of a seat back of a vehicle seat, and a seat back frame disposed on a seat front side with respect to the backboard portion. A pair of left and right frame fixing portions fixed to the pair of left and right side frames, a front end portion is integrally or integrally connected to a seat width direction inner end portion of the frame fixing portion, and a rear end portion of the backboard portion It is characterized by comprising a pair of left and right front-rear extending portions that are integrally or integrally connected with the end portion in the seat width direction and that can be extended in the front-rear direction of the seat by providing an extra length portion. Yes.

  The resin seat backboard according to claim 1, wherein the backboard portion disposed on the back side of the seat back of the vehicle seat and the pair of left and right frame fixing portions fixed to the pair of left and right side frames in the seat back frame. Are connected by a pair of left and right extending portions in the front-rear direction. In the front-rear direction extending portion, the front end portion is connected to the inner end portion in the seat width direction of the frame fixing portion, and the rear end portion is connected to the end portion in the seat width direction of the backboard portion. For this reason, for example, when a load from an occupant at the time of a rear impact acts on the backboard portion, a tensile force to the seat rear side acts on the front-rear direction extending portion, and the front-rear direction extending portion and the frame fixing portion are connected. Stresses due to bending and tension are concentrated on the part. When this stress increases, local deformation (plastic deformation) may occur in the connecting portion. However, in the present invention, a surplus length portion is provided in the front-rear direction extending portion, so that the front-rear direction extending portion is provided. Is stretched in the longitudinal direction of the seat by the tensile force. Thereby, since the stress concentration can be relaxed, the local deformation as described above can be prevented or suppressed.

  A resin seat backboard according to a second aspect of the present invention is the resin seat backboard according to the first aspect, wherein the frame fixing portion is disposed to face the front end surface of the side frame, A front wall in which a front end portion of the front-rear direction extending portion is coupled to an inner end portion in the direction, and a seat width direction outer side surface of the side frame that extends from a seat width direction outer end portion of the front wall to a seat rear side. And an outer wall fixed to the outer wall.

  In the resin seat backboard according to claim 2, when a load on the seat rear side acts on the backboard portion, the inner end portion in the seat width direction of the front wall of the frame fixing portion has the front-rear extending portion. To the rear side of the seat. The front wall is disposed to face the front end surface of the side frame, and the outer wall extending from the outer end portion in the seat width direction of the front wall to the seat rear side is located on the outer surface in the seat width direction of the side frame. It is fixed. For this reason, when the front wall is pulled through the longitudinally extending portion as described above, the front wall abuts the front end surface of the side frame, thereby supporting the frame fixing portion from the rear side of the seat by the side frame. can do. Thereby, the fixed strength of the frame fixing part with respect to the side frame can be improved.

  The resin seat backboard according to the invention described in claim 3 is the resin seat backboard according to claim 1 or 2, and extends in the seat width direction on the seat front side of the backboard portion, Both ends of the seat width direction are integrally or integrally connected to the pair of front and rear direction extending portions, and have a resin spring portion that can be bent and deformed to the rear side of the seat by a load from the front side of the seat, The surplus portion is characterized in that all or part of the surplus portion is disposed on the front side of the seat with respect to the resin spring portion.

  In the resin seat backboard according to claim 3, both end portions in the seat width direction of the resin spring portion disposed on the front side of the seat of the backboard portion are coupled to the pair of front and rear direction extending portions. Since the resin spring portion can be bent and deformed to the rear side of the seat by a load from the front side of the seat, the cushioning property of the seat back can be ensured. Moreover, for example, when a load from the occupant at the time of a rear impact acts on the resin spring portion, the extra length portion, which is all or partly disposed on the front side of the seat with respect to the resin spring portion, is extended in the seat front-rear direction. . As a result, stress concentration at the connecting portion between the resin spring portion and the longitudinally extending portion can be alleviated, so that local deformation of the connecting portion can be prevented or suppressed.

  A resin seat backboard according to a fourth aspect of the present invention is the resin seat backboard according to the third aspect, wherein the extra length portion extends inward in the seat width direction and toward the rear side of the seat. An inclined portion is provided, and an end of the resin spring portion in the sheet width direction is connected to the inclined portion.

  In the resin seat backboard according to claim 4, the sheet width direction end portion of the resin spring portion is connected to the inclined portion provided in the extra length portion. Since the inclined portion extends toward the inner side in the seat width direction and toward the rear side of the seat, the angle formed by the front side of the seat between the inclined portion and the resin spring portion is set to 90 degrees or more and 180 degrees or less. . Thereby, since the deformation angle of the angle formed when the resin spring portion is bent toward the rear side of the seat can be reduced, the bending stress generated in the connecting portion between the inclined portion (extra length portion) and the resin spring portion is reduced. Can be reduced.

  The resin seat backboard according to the invention described in claim 5 is the resin seat backboard according to any one of claims 1 to 4, wherein the extra length portion is the extension portion in the front-rear direction. It is characterized by being provided continuously from the upper end to the lower end.

  In the resin seat backboard according to claim 5, since the surplus portion is continuously provided from the upper end to the lower end of the front / rear direction extending portion, the front / rear direction extending portion is formed by a tensile force in the front / rear direction of the seat. It can be stretched well.

  The resin seat backboard according to the invention described in claim 6 is the resin seat backboard according to any one of claims 1 to 5, wherein the extra length portion is seen in a plan view. In some cases, a plurality of curved surfaces are continuously formed in the front-rear direction of the seat to form a wave shape.

  In the resin seat backboard according to claim 6, when a surplus length portion provided in the front-rear direction extending portion is viewed in a plan view, a plurality of curved surfaces (mountain valleys) are continued in the front-rear direction of the seat. It is formed in a wave shape. Thereby, the extension amount of the front-back direction extension part can be increased compared with the case where the surplus length part in which only one big peak was formed in the front-back direction extension part, for example.

  The resin seat back board according to the invention of claim 7 is the resin seat back board of claim 5 or claim 6, wherein the extra length portion has either one of the seat back height directions. It is characterized by a draft angle so that it can be punched.

  In the resin seat backboard according to claim 7, in order to form the surplus portion provided continuously from the upper end to the lower end of the front-rear direction extending portion, a gold is formed on either side of the seat back height direction. It is desirable to take out the mold. In the present invention, in consideration of this point, since the draft is set in the extra length portion, the die can be punched out in any one of the seat back height directions.

  The resin seat backboard according to an eighth aspect of the present invention is the resin seat backboard according to any one of the first to seventh aspects, wherein the backboard portion has both end sides in the sheet width direction. A frame facing portion is provided to be opposed to the rear wall portion of the side frame from the front side of the seat.

  In the resin seat backboard according to claim 8, the frame facing portions provided on both ends of the backboard portion in the seat width direction are disposed to face the rear wall portion of the side frame from the front side of the seat. . For this reason, when the backboard part is displaced rearward due to the extension of the longitudinally extending part, the frame facing part (backboard part) is set to contact directly or indirectly with the rear wall part of the side frame. can do. Thereby, since the backboard part can be supported by the rear wall part of the side frame, the stress generated in the configuration on the front side of the seat with respect to the backboard part can be reduced.

  According to a ninth aspect of the present invention, a vehicle seat includes: a seat back frame; a seat back pad supported by the seat back frame; a seat cover that covers a surface of the seat back pad; and the seat back frame. The resin seat backboard according to any one of claims 1 to 8, which is attached to a pair of left and right side frames.

  In the vehicle seat according to the ninth aspect, the seat back pad supported by the seat back frame is covered with the seat cover. A resin seat back board is attached to the pair of left and right side frames in the seat back frame. Since this seat backboard is described in any one of claims 1 to 8, the above-described effects can be obtained.

  As described above, local deformation can be prevented or suppressed in the resin seat backboard and the vehicle seat using the resin seat backboard according to the present invention.

It is a disassembled perspective view of the seat back of the vehicle seat which concerns on 1st Embodiment of this invention. It is a perspective view which shows the state by which the seat back board was assembled | attached to the seat back frame shown by FIG. FIG. 3 is an enlarged plan sectional view showing a cut surface along the line 3-3 in FIG. 2. FIG. 4 is a plan sectional view showing a state in which a load from an occupant at the time of a rear collision is applied to the seat back board shown in FIG. 3. FIG. 5 is an enlarged plan sectional view showing a part of FIG. 4 in an enlarged manner. It is a plane sectional view corresponding to Drawing 3 showing a comparative example of a 1st embodiment of the present invention. FIG. 7 is a cross-sectional plan view showing a state in which a load from an occupant is applied to the seat back board shown in FIG. FIG. 8 is an enlarged plan sectional view showing a part of FIG. 7 in an enlarged manner. FIG. 8 is an enlarged plan sectional view showing a part of FIG. 7 (parts different from FIG. 8) in an enlarged manner. It is a plane sectional view showing the partial composition of the seat back of the vehicular seat concerning a 2nd embodiment of the present invention. FIG. 11 is an enlarged plan cross-sectional view in which a part of FIG. 10 is enlarged, (A) is a diagram showing a normal state, and (B) is a case where a load from an occupant is applied to the back spring main body at the time of a rear collision. FIG. FIG. 11 is a plan sectional view showing a state in which a load from an occupant at the time of a rear collision is applied to the seat back board shown in FIG. 10.

[First Embodiment]
Hereinafter, the vehicle seat 10 according to the first embodiment of the present invention will be described with reference to FIGS. In these drawings, an arrow FR appropriately shown indicates the vehicle front side, an arrow UP indicates the vehicle upper side, and an arrow IN indicates the vehicle width direction inner side.

<Overall configuration>
FIG. 1 is an exploded perspective view of a seat back 12 corresponding to the backrest of the vehicle seat 10 according to the present embodiment. In FIG. 1, the angle at which each component is viewed is slightly changed. The vehicle seat 10 includes a seat cushion (not shown) on which an occupant sits, and a seat back 12 is tiltably connected to a rear end portion of the seat cushion.

  As shown in FIG. 1, the seat back 12 includes a metal seat back frame 14 that constitutes a skeleton member of the seat back 12, and a resin spring integrated back board (hereinafter simply referred to as “ A seat back pad 18 that constitutes a cushion material of the seat back 12 and is attached from the front side of the seat back board 16 and supported by the seat back frame 14; and a seat back pad 18 And a seat cover (skin) 20 that covers the surface (mainly the front surface). Hereinafter, each component will be described in detail.

<Configuration of the seat back frame 14>
As shown in FIGS. 1 to 3, the seat back frame 14 is viewed from the front (when viewed from the front of the vehicle. Hereinafter, the direction of the vehicle and the direction of the vehicle seat 10 are assumed to be the same. )) In the shape of a rectangular frame. Specifically, a pair of left and right side frames 26 arranged to face each other in the seat width direction (vehicle width direction), an inverted U-shaped upper frame 28 connecting the upper ends of the left and right side frames 26, The lower frame 30 connecting the lower ends of the side frames 26 in the vehicle width direction. The seat back 12 includes all four members including the upper frame 28 by press molding, but other frame structures may be adopted. For example, only the upper frame may be formed of a pipe material bent in an inverted U shape, or the upper frame and a pair of left and right side frames may be configured of a single pipe material bent in an inverted U shape.

  Next, the sectional structure of the left and right side frames 26 will be described. As shown in FIGS. 2 and 3, the side frame 26 includes a side wall portion 26A, a front wall portion 26B, and a rear wall portion 26C. When viewed alone, the side frame 26 is substantially L-shaped in a plan view. When viewed as a pair on the left and right, it is formed in an open cross-sectional shape with the inside facing the sheet width direction opened in a plan view. The width of the side wall portion 26A becomes narrower from the lower end portion toward the upper end portion as a whole. A plurality of mounting holes 32 (see FIG. 1) are formed in the lower portion of the side wall portion 26A so as to be spaced apart from each other in the vertical direction. The front wall portion 26B extends inward in the seat width direction from the front end of the side wall portion 26A, and is curved so as to be convex toward the front side of the seat. The rear wall portion 26C extends inward in the seat width direction from the rear end of the side wall portion 26A, and the front end portion is obliquely bent toward the front side of the vehicle and protrudes in a substantially V-shaped cross section toward the front side of the seat at the intermediate portion. The protruding portion 26C1 is provided. The width of the rear wall portion 26C is set sufficiently wider than the width of the front wall portion 26B.

<Configuration of seat back board 16>
Next, the configuration of the seat back board 16 will be described in detail. As shown in FIGS. 1 to 3, the seat back board 16 is formed of a resin material, and has a back board portion 36 disposed on the back side of the seat back 12 and a seat more than the back board portion 36. A pair of left and right frame fixing portions 49 disposed on the front side and fixed to the pair of left and right side frames 26, a seat width direction inner end portion of the frame fixing portion 49 and a seat width direction end portion of the backboard portion 36 are seated. A load acting direction (seat rear side) is applied between a pair of left and right front / rear extending portions 50 connected in the front / rear direction and a pair of left / right front / rear extending portions 50, and a load is applied to the seat back rear side. ) And a back spring portion 38 (resin spring portion) that can be elastically bent and deformed.

  The backboard portion 36 includes a board main body 40 that is formed slightly smaller than the seat back frame 14, a U-groove engaging portion 42 that is integrally formed on the outer peripheral portion of the board main body 40, and the engaging portion 42. And a pair of left and right frame facing portions 43 that are integrally extended from the lower side to the outer side in the seat width direction. More specifically, the board body 40 is formed slightly smaller than the inner peripheral edge of the opening of the seat back frame 14 formed in a rectangular frame shape. In the assembled state to the seat back frame 14, the board body 40 is disposed slightly behind the seat between the front end portions (inner end portions) of the rear wall portions 26 </ b> C of the left and right side frames 26. Therefore, the board body 40 can be assembled from the seat front side of the seat back frame 14 (see FIG. 3). The cross-sectional shape of the locking portion 42 is U-shaped with the seat rear side open. The locking portion 42 is used to lock an outer peripheral portion of the seat cover 20 to be described later, but also has a function of reinforcing the plate-like board body 40 and increasing the surface rigidity of the entire backboard portion 36. ing.

  The frame facing portion 43 is once extended from the front end portion of the locking portion 42 to the front side of the seat and then extended outward in the seat width direction via a bent portion. The frame facing portion 43 is disposed to face the rear wall portion 26C of the side frame 26 from the front side of the seat, and a predetermined gap 45 is formed between the frame facing portion 43 and the rear wall portion 26C. Has been.

  The frame fixing portion 49 is formed in a substantially L shape in a plan view, and includes a front wall 49A that abuts (opposes) the front end surface of the front wall portion 26B of the side frame 26 in a surface contact state, and a front wall 49A. The outer wall 49 </ b> B extends from the outer end in the seat width direction toward the rear side of the seat and is in contact with the outer side surface in the seat width direction of the side wall portion 26 </ b> A of the side frame 26. A through hole 47 (see FIG. 1) is formed in the outer wall 49B, and a resin clip 51 (fixing tool) inserted through the through hole 47 is fitted and locked in the mounting hole 32 of the side wall portion 26A. Thereby, the frame fixing part 49 is fixed to the side frame 26. As fixing means for fixing the frame fixing portion 49 to the side frame 26, a structure in which a resin clip is integrally formed on the outer wall 49B and fitted into the mounting hole 32, a rivet, a screw, a screw or a bolt and a weld nut, etc. Various modes, such as a configuration for fastening with a fastener and a configuration for bonding with a structural adhesive, are applicable.

  The longitudinally extending portion 50 extends in the seat longitudinal direction inside the side wall portion 26A of the side frame 26 in the seat width direction, and the front end portion is integrally connected to the seat width direction inner end portion of the front wall 49A. (Refer to the connection part C1 in FIG. 3). Further, the rear end portion of the front-rear direction extending portion 50 is integrally connected to the end portion in the seat width direction of the backboard portion 36 (see the connecting portion C2 in FIG. 3).

  On the front side (front-rear direction intermediate portion) of the front-rear direction extending portion 50, a corrugated portion 50A is provided as an extra length portion. The wavy portion 50A is formed in a wavy shape by continuing a plurality of curved surfaces (mountain valleys) in the front-rear direction of the seat when viewed in plan view, and the front end portion and the rear end portion of the front-rear extension portion 50 are formed. A plurality of bulging portions bulging in the sheet width direction with respect to the connecting straight line are provided. In other words, the corrugated portion 50A includes a plurality of bulged portions that diverge from the straight line and bulge in the sheet width direction. The wavy portion 50A is provided continuously from the upper end to the lower end of the front-rear direction extending portion 50, and the front-rear direction extending portion 50 is elastically extendable in the front-rear direction of the seat at the wavy portion 50A. Yes.

  The back spring portion 38 is disposed on the front side of the seat of the back board portion 36 and has a plurality of back spring main body portions 48 extending in the seat width direction. These back spring main body portions 48 are integrally connected at both ends in the seat width direction (both ends in the longitudinal direction) to the middle portion in the front-rear direction of the pair of left and right front-rear extending portions 50 (see connection portion C3 in FIG. 3). ). Thus, the plurality of back spring main body portions 48 are connected in the seat back height direction by the pair of left and right front-rear extending portions 50. Further, the entire wavy portion 50A described above (the whole) is disposed on the front side of the seat with respect to the back spring main body 48, and the back spring main body 48 is perpendicular to the longitudinally extending portion 50 in a plan view. It is connected to. It should be noted that the number of the back spring main body portions 48 constituting the back spring portion 38 is arbitrary, and can be changed as appropriate in relation to the required cushion performance. Therefore, the back spring main body portion may be widened up and down to be one, or conversely, may be two or more than four.

  The back spring main body 48 is formed in a wave shape by continuing a plurality of curved surfaces in the sheet width direction when viewed in a plan view shown in FIG. For this reason, the back spring main body 48 is expanded by the wave-like portion 48A when a load is applied to the backboard portion 36 side (seat rear side), and is thereby bent and deformed toward the backboard portion 36 side which is the load acting direction ( Elastic deformation).

  Further, the back spring main body 48 is disposed at a position separated by a predetermined distance on the front side of the seat of the back board 36 described above. That is, a predetermined gap 52 is formed between the back spring main body portion 48 and the back board portion 36. The back spring body 48 can be elastically deformed within the range of the gap 52. That is, the backboard portion 36 also functions as a limiting member that limits the amount of bending of the back spring main body portion 48 to a predetermined amount or less.

  In addition, when the resin is molded by using a slide mold (not shown), the wave-shaped portion 48 of the back spring main body portion 48 and the wave-shaped portion 50A of the front-rear direction extending portion 50 are arranged in any of the seat back height directions. A taper shape (draft angle) is set so that it can be removed from one side (here, the lower side).

  Although not shown, an upper back spring main body (not shown) having a configuration basically similar to that of the back spring main body 48 is provided above the three back spring main bodies 48. The upper back spring main body is integrated with the upper side of the back board 36 by heat welding or the like, and both ends in the seat width direction are fixed to the left and right side frames by resin clips or the like. 38 is constituted.

<Configuration of the seat back pad 18>
As shown in FIG. 1, the seat back pad 18 is made of a foam such as urethane foam, and includes a pad center portion 62 and a pair of left and right pad side portions 66. The pad center portion 62 has an upper end engaged with the upper frame 28 of the seat back frame 14 from above the seat back, and a lower end connected to a connecting rod (not shown) that connects the lower ends of the side frames 26 in the seat width direction. It is locked from the back lower side. The lower side of the pad center portion 62 is supported from the back side of the seat by the back spring portion 38, and the upper side of the pad center portion 62 is supported from the back side of the seat by an upper back spring portion (not shown).

  As shown in FIG. 3, the pad side portion 66 has a substantially C-shaped cross section, and is mounted so as to be wound around the side frame 26. The pad side portion 66 bulges to the front side of the seat from the central portion 62, and has a shape that ensures side support for the occupant.

<Configuration of the seat cover 20>
As shown in FIG. 1, the seat cover 20 is formed in a size that can cover the seat back pad 18 from the front side. At an appropriate position on the outer periphery of the seat cover 20, an outer periphery locking portion 80 having a hook shape is attached by sewing. The outer peripheral locking portion 80 is inserted and locked to the locking portion 42 of the backboard portion 36 from the seat rear side. Thereby, the outer peripheral part of the seat cover 20 is detachably locked to the backboard part 36. The seat cover 20 is provided with a plurality of locking portions (not shown), and these locking portions are locked to the seat back board 16.

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

  The vehicle seat 10 having the above configuration includes the seat back board 16 in which a resin back spring part 38 is integrally formed with a resin back board part 36. Then, the seat back board 16 is fitted to the metal seat back frame 14 from the front side of the seat. Specifically, the left and right frame fixing portions 49 are engaged with the left and right side frames 26 from the front side of the seat, and in this state, are fixed to the side frames 26 from the outside in the seat width direction. Thereafter, the seat back pad 18 is attached to the seat back frame 14 from the front side of the seat, and the seat cover 20 is further put on the seat back pad 18.

  The seat back 12 assembled as described above is attached to a seat cushion (not shown) to form a vehicle seat 10. When the occupant sits on the vehicle seat 10, a load on the rear side of the seat back is input to the back spring portion 38 via the seat cover 20 and the seat back pad 18. For this reason, the back spring main body 48 and the upper back spring main body (not shown) are bent and deformed to the rear side of the seat back which is the load acting direction. Further, since the load at this time is transmitted to the left and right side frames 26 via the longitudinally extending portion 50 and the frame fixing portion 49, a reaction force from the side frame 26 to the front side of the seat is generated.

  Thus, when a load is input from the occupant to the back spring portion 38, the load is deformed and contributes to securing the cushioning property of the seat back 12, and the load itself is transmitted to the left and right side frames 26 to be transmitted to the left and right side frames. 26. As a result, the cushion performance of the seat back 12 is sufficiently ensured. Further, since the back spring portion 38 is made of resin and is provided integrally with the back board portion 36, the number of parts and the number of assembling steps are reduced as compared with the case where the back spring portion 38 is formed of a metal seat back spring. Is done. As a result, according to the present embodiment, the cushion performance of the seat back 12 can be sufficiently secured, and further weight reduction and cost reduction can be achieved.

  In addition, in the present embodiment, the corrugated portion 50 </ b> A (extra length portion) is provided in the longitudinally extending portion 50 of the seat back board 16, thereby preventing or effectively preventing local deformation of the seat back board 16. Can be suppressed.

  That is, as in the comparative example 100 shown in FIGS. 6 and 7, when the thickness of each part is the same as that of the seat backboard 16 and the wavy part 50 </ b> A is omitted, the tension of the longitudinally extending part 50 is The rigidity K2 may be larger than the bending rigidity K1 of the connecting part C1 between the front-rear direction extending part 50 and the frame fixing part 49 (K2> K1). In this case, a load F (see FIG. 7) from the occupant P at the time of the rear impact acts on the back spring portion 38 and the back board portion 36, thereby pulling the left and right longitudinally extending portions 50 toward the seat rear side. When the force f1 (see FIGS. 7 and 8) is applied, stress concentrates on the connecting portion C1 by bending and pulling (see arrow A in FIG. 8). This stress may cause local deformation (plastic deformation) in the connecting portion C1.

  On the other hand, in this embodiment, as shown in FIG. 3, the front-rear direction extending portion 50 A (extra length portion) is provided in the front-rear direction extending portion 50 of the seat back board 16. The tensile rigidity K2 of 50 is smaller than the bending rigidity K1 of the connecting portion C1 (K2 <K1). Therefore, as shown in FIG. 4, when a tensile force f1 toward the seat rear side is applied to the longitudinally extending portion 50, the longitudinally extending portion 50 is moved in the longitudinal direction of the seat by the tensile force f1. Stretched. Thereby, since the bending force and tensile force which act on the connection part C1 can be reduced, the stress concentration in the connection part C1 can be relieved (refer arrow B of FIG. 5). Therefore, local deformation as described above can be prevented or effectively suppressed. 4 and 7, the seat back pad 18 and the seat cover 20 are not shown for convenience of explanation.

  Further, in the comparative example 100, when the load F from the occupant P at the time of the rear impact acts on the back spring main body portion 48, the connecting portion C3 between the longitudinally extending portion 50 and the back spring main body portion 48 becomes the back spring main body 48. It is pulled through the portion 48 toward the inner side in the seat width direction and the rear side of the seat (see the arrow f2 in FIG. 9). As a result, stress due to bending and tension concentrates on the connecting portion C3 (see arrow D in FIG. 9), and local deformation (plastic deformation) may occur in the connecting portion C3.

  On the other hand, in the present embodiment, the wavy portion 50A of the front-rear direction extending portion 50 is disposed on the front side of the seat from the connecting portion C3. For this reason, since the said wavy part 50A expand | extends, the stress concentration in the connection part C3 can be relieved, Therefore The local deformation | transformation in the connection part C3 can be prevented or suppressed effectively.

  Further, in the comparative example 100, when the longitudinally extending portion 50 is pulled to the rear side of the seat, the left and right side frames 26 are twisted and deformed in the direction in which the front end portions approach each other as shown in FIG. (See arrow E in FIG. 7). As a result, the rigidity of the seat back frame 14 with respect to the load on the rear side of the seat is reduced, and the seat back frame 14 is easily deformed to the rear side of the seat.

  On the other hand, in this embodiment, since the longitudinally extending portion 50 extends as described above, the load applied to the side frames 26 can be reduced, so that the torsional deformation of the left and right side frames 26 is suppressed. (See FIG. 4). Thereby, the rigidity of the seat back frame 14 at the time of a rear collision can be ensured satisfactorily.

  In addition, in the present embodiment, the frame facing portions 43 provided on both ends of the backboard portion 36 in the seat width direction are disposed so as to face the rear wall portion 26C of the side frame 26 from the seat front side. For this reason, when the backboard part 36 is displaced rearward due to the extension of the longitudinally extending part 50, the frame facing part 43 (backboard part 36) contacts the rear wall part 26C of the side frame 26. Accordingly, the backboard portion 36 is supported from the rear side of the seat by the rear wall portion 26 </ b> C of the side frame 26. Thereby, the stress which arises in the structure of the seat front side rather than the backboard part 36 in the seat backboard 16 can be reduced. In addition, since the load acting on the side frame 26 is distributed to the front end side and the rear end side of the side frame 26, the torsional deformation of the side frame 26 can also be suppressed. Further, since the rear wall portion 26C is provided with a protruding portion 26C1 protruding to the front side of the seat, the frame facing portion 43 is brought into contact with the rear wall portion 26C by changing the protruding height of the protruding portion 26C1. The timing of contact can be adjusted.

  Further, in the present embodiment, the front wall 49A of the frame fixing portion 49 is in contact with the front wall portion 26B of the side frame 26 from the front side of the seat, and from the outer end in the seat width direction of the front wall 49A. The outer wall 49 </ b> B extending to the side frame 26 </ b> A is fixed to the outer surface of the side frame 26 </ b> A in the seat width direction. For this reason, when the seat width direction inner side end portion (connecting portion C1) of the front wall 49A is pulled to the seat rear side via the front-rear direction extending portion 50, the front wall 49A, that is, the frame fixing portion 49 is connected to the side frame. 26 can be supported from the rear side of the seat. Thereby, the fixing strength of the frame fixing part 49 with respect to the side frame 26 can be improved.

  Further, in the present embodiment, since the wavy portion 50A is continuously provided from the upper end to the lower end of the front / rear direction extending portion 50, the front / rear direction extending portion 50 is favorably formed by the tensile force f1 to the rear side of the seat. Can be stretched.

  Furthermore, in this embodiment, the wavy portion 50A, which is the extra length portion of the longitudinally extending portion 50, is formed in a wavy shape by continuing a plurality of curved surfaces in the front-rear direction of the seat when viewed in a plan view. Yes. Thereby, the extension amount of the front-back direction extension part can be increased compared with the case where the surplus length part in which only one big peak was formed in the front-back direction extension part, for example.

  In this embodiment, in the seat back board 16, the back spring part 38 is integrally formed with the back board part 36. For this reason, when manufacturing the seat back board 16, it is desirable to take a method of removing a mold (slide mold) in either one of the seat back height directions. In consideration of this point, the wavy portion 50A of the longitudinally extending portion 50 and the wavy portion 48 of the back spring body portion 48 are tapered so that the slide mold can be removed downward in the seat back height direction. (Gradient) is set. Therefore, the seat back board 16 can be manufactured efficiently.

  Next, another embodiment of the present invention will be described. In addition, about the structure and effect | action similar to the said 1st Embodiment, the same code | symbol as the said 1st Embodiment is provided, and the description is abbreviate | omitted.

[Second Embodiment]
FIG. 10 is a plan sectional view showing a partial configuration of a vehicle seat 200 according to the second embodiment of the present invention. In FIG. 10, the seat back pad 18 and the seat cover 20 are not shown. In this embodiment, the configuration is basically the same as that of the first embodiment. In this embodiment, the wavy portion 50A of the front-rear direction extending portion 50 is on the rear side of the seat with respect to the first embodiment. Is formed. In this embodiment, the end portion in the seat width direction of the back spring main body 48 is connected to the inclined portion 50A1 provided in the waved portion 50A (see the connecting portion C3 in FIG. 10). The inclined portion 50A1 extends toward the inner side in the seat width direction and toward the rear side of the seat, and an angle θ (see FIG. 12A) formed by the wavy portion 50A and the back spring main body portion 48 on the front side of the seat is 90. It is set to not less than 180 degrees and not more than 180 degrees.

  Also in this embodiment, since the configuration is basically the same as that of the first embodiment, the same effects as the first embodiment are obtained. In addition, in this embodiment, as described above, the angle θ (see FIG. 11A) formed by the wavy portion 50A and the back spring body portion 48 on the front side of the seat is set to 90 degrees or more and 180 degrees or less. Thereby, as shown in FIG. 12, since the deformation angle of the connecting portion C3 when the load F from the occupant P at the time of the rear impact is applied to the back spring main body portion 48 becomes small, the stress generated in the connecting portion C3 is reduced. Further reduction can be achieved. That is, the stress S generated in the connecting part C3 is constituted by the tensile stress St and the bending stress Sm (S = St + Sm). The bending stress Sm is proportional to the deformation angle Δθ (see FIG. 11B) from the formed angle θ (Sm = Δθ / θ). For this reason, the bending stress Sm can be reduced by setting the formed angle θ large. Therefore, it is possible to further reduce the stress S generated in the connecting portion C3.

[Supplementary explanation of the above embodiment]
In each of the embodiments described above, the resin back spring portion 38 (resin spring portion) is integrally formed with the resin back board portion 36. However, the present invention is not limited to this, and the resin back spring portion 36 is formed with the resin back spring portion 36. 38 may be provided integrally. That is, the backboard part 36 and the back spring part 38 may be manufactured separately and then integrated by welding or the like. Further, the back spring main body 48 and the longitudinally extending portion 50 constituting the back spring portion 38 may be manufactured as separate parts and then integrated by welding or the like. Alternatively, the frame fixing portion 49 and the longitudinally extending portion 50 may be manufactured as separate parts and then integrated by welding or the like. Further, the back spring portion 38 according to the above embodiment may be omitted, and another elastic deformation portion may be provided. For example, a bellows-like elastic deformation portion may be provided on the seat front side of the backboard portion 36, and the elastic deformation portion may be elastically deformed in the compression direction by a load on the seat rear side. Further, for example, an elastic deformation portion formed in a trapezoidal cross section in a plan view may be provided on the seat front side of the backboard portion 36, and the elastic deformation portion may be elastically deformed by a load on the seat rear side.

  Moreover, in each said embodiment, the flame | frame opposing part 43 provided in the sheet | seat width direction both ends of the backboard part 36 was arrange | positioned facing the rear wall part 26C of the side frame 26 from the sheet | seat front side. However, the present invention is not limited to this, and the frame facing portion 43 may be omitted.

  Moreover, in each said embodiment, it was set as the structure by which the draft was set to the wavy part 50A of the front-back direction extension part 50, However, It is not restricted to this, The shaping | molding method of the seat backboard which concerns on this invention changes suitably. The draft angle may be omitted.

  In each of the above embodiments, the wavy portion 50A is configured as an extra length portion. However, the configuration is not limited thereto, and the extra length portion is formed on a straight line connecting the front end portion and the rear end portion of the longitudinally extending portion. Any shape may be used as long as it is removed, and the shape can be changed as appropriate.

  Moreover, in the said embodiment, although the wavelike part 50A (extra length part) was set as the structure provided continuously from the upper end to the lower end of the front-back direction extension part 50, it is not restricted to this, The site | part which is not continuous is provided. Even if it exists, what is necessary is that the extension of the front-rear direction extending portion 50 is allowed.

  Further, in each of the above embodiments, the frame fixing portion 49 includes the front wall 49A and the outer wall 49B, and the outer wall 49B is fixed to the outer side surface in the seat width direction of the side frame 26. The configuration of the fixed part can be changed as appropriate. For example, the outer wall may be omitted, and the front wall may be fixed to the front end surface of the side frame. Further, the frame fixing portion may be fixed to the inner side surface in the seat width direction of the side frame. In each of the above embodiments, the front wall 49A of the frame fixing portion 49 is disposed in contact with the front end surface of the side frame 26. However, the present invention is not limited thereto, and the front wall of the frame fixing portion and the side frame A configuration may be adopted in which a slight gap is secured between the front end surface.

  In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiments.

DESCRIPTION OF SYMBOLS 10 Vehicle seat 12 Seat back 14 Seat back frame 16 Seat back board 18 Seat back pad 20 Seat cover 26 Side frame 36 Back board part 38 Back spring part (resin spring part)
43 Frame facing portion 49 Frame fixing portion 49A Front wall 49B Outer wall 50 Front-rear direction extending portion 50A Wave portion (extra length portion)
50A1 inclined part

Claims (9)

A backboard portion disposed on the back side of the seat back of the vehicle seat;
A pair of left and right frame fixing portions disposed on the front side of the seat from the backboard portion, and fixed to a pair of left and right side frames in the seat back frame;
The front end portion is integrally or integrally connected with the seat width direction inner end portion of the frame fixing portion, the rear end portion is integrally or integrally connected with the seat width direction end portion of the backboard portion, and the extra length. A pair of left and right front-rear direction extending parts that are extendable in the front-rear direction of the seat by providing the part,
Resin seat backboard with   The frame fixing portion is arranged to face the front end surface of the side frame, and has a front wall in which a front end portion of the front-rear direction extending portion is connected to an inner end portion in the seat width direction, and a seat width direction of the front wall The resin seat backboard according to claim 1, further comprising: an outer wall that extends from an outer end portion to a seat rear side and is fixed to an outer side surface of the side frame in a seat width direction.   The seat extends in the seat width direction on the seat front side of the backboard portion, and both end portions in the seat width direction are integrally or integrally connected to the pair of front and rear direction extending portions, and the seat is driven by a load from the seat front side. 3. The resin spring portion which is configured to be able to bend and deform backward, and the extra length portion is entirely or partially disposed on the front side of the seat with respect to the resin spring portion. Plastic seat backboard.   The surplus length portion is provided with an inclined portion extending inward in the seat width direction and toward the rear side of the seat, and an end portion in the seat width direction of the resin spring portion is connected to the inclined portion. The resin seat backboard described.   5. The resin seat backboard according to claim 1, wherein the extra length portion is provided continuously from the upper end to the lower end of the front-rear direction extending portion.   The said extra length part is formed in the wave form by making a some curved surface continue in a sheet | seat front-back direction, when it sees by planar cross section view, The resin product of any one of Claims 1-5 Seat back board.   The resin seat back board according to claim 5 or 6, wherein a draft angle is set in the extra length portion so that the die can be punched in any one of the seat back height directions.   The frame opposing part arrange | positioned facing the back wall part of the said side frame from the front side of a sheet | seat is provided in the sheet | seat width direction both ends side of the said backboard part. The resin-made seat back board of Claim 1. A seat back frame;
A seat back pad supported by the seat back frame;
A seat cover covering the surface of the seat back pad;
The resin seat back board according to any one of claims 1 to 8, wherein the resin seat back board is attached to a pair of left and right side frames in the seat back frame.
Vehicle seat equipped with

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