JP2010220748A - Seat frame and method for manufacturing the seat frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat frame improved in productivity and strength. <P>SOLUTION: The seat frame 10 includes right and left side frames 11a and 11b and a connecting frame 11c for connecting ends of both side frames 11a and 11b. The seat frame 10 is formed of a fiber reinforced composite material including a three-dimensional braiding (three-dimensional braid) extending from one side frame 11a to the other side frame 11b through the connecting frame 11c, as a reinforcing fiber. The seat frame 10 is formed into a hollow shape. The three-dimensional braiding is formed circumferentially into a cylindrical shape without a seam. The three-dimensional braiding is formed so that the side frames 11a and 11b have a cross-sectional shape smaller on one end side, i.e. on the side to the connecting frame 11c, than on the other end side (base end side). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a seat frame and a seat frame manufacturing method, and more particularly, to a seat frame constituting a seat of a vehicle, a ship, an aircraft, or the like and a manufacturing method thereof.

  Conventionally, automobile seat frames are mainly made of metal, and mass-produced products are mainly made of iron. When the seat frame is made of metal, the weight is heavy, which is an impediment to improving fuel consumption. In order to reduce the weight of the seat frame, it has been proposed to form the seat frame with a fiber reinforced resin (see, for example, Patent Document 1). In Patent Document 1, as shown in FIGS. 7 (a) and 7 (b), the left and right side frames 52 and the upper and lower frames 53 in which the frame main body 51 is formed of a fiber reinforced resin plate are bonded and fixed to each other. A seat back frame provided with a back plate portion 54 made of a thermosetting resin on an inner portion of the frame main body 51 is described as a prior art. In this seat back frame, since the frame main body 51 is obtained by joining frame members that are individually punched and molded from plate materials having a constant thickness, the strength of the joint portion is low and the dimension in the thickness direction is reduced. There can be no change and there is no design freedom. Therefore, Patent Document 1 proposes a seat back frame for solving these problems. As shown in FIG. 8A, the improved seat back frame has a frame main body 61 in which left and right side frame portions 62, upper and lower frame portions 63, and a back plate portion 64 are integrally formed using fiber reinforced resin. Is formed. As shown in FIG. 8B, each frame portion is formed in a substantially U-shaped cross section, and a back plate portion 64 is continuously formed in a portion surrounded by the U-shaped inner end of the frame portion.

Japanese Utility Model Publication No. 63-175958

  However, in the seat back frame shown in FIG. 8 proposed in Patent Document 1, the back plate portion 64 is essential, the back plate portion 64 is omitted, and the side frame portions 62 and the upper and lower frame portions 63 are substantially reversed. It cannot be applied to a U-shaped seat frame. In order to integrally form such a substantially inverted U-shaped seat frame using fiber reinforced resin, as shown in FIG. 9, a plurality of prepregs 70a punched from a planar prepreg 70 into a substantially inverted U shape are provided. It is necessary to laminate and heat and press. However, in the method of stacking and forming a plurality of prepregs 70a punched into a substantially inverted U shape, there is a problem that waste is increased in forming the substantially inverted U-shaped prepreg 70a.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a seat frame capable of improving productivity and strength and a manufacturing method thereof.

  In order to achieve the above object, according to the first aspect of the present invention, the left and right side frames and a connecting frame that connects between one end portions of the two side frames are connected to each other from one side frame through the connecting frame. It is formed of a fiber reinforced composite material having three-dimensional braiding extending over the side frames as reinforcing fibers. Here, “three-dimensional braiding” means a three-dimensionally formed braided tissue.

  In this invention, since three-dimensional braiding is used as the reinforcing fiber, the productivity is improved as compared with the case where a plurality of prepregs are laminated. Further, the strength is improved as compared with the case where prepregs are laminated, planar woven fabrics are laminated as reinforcing fibers, or fibers are simply arranged.

  According to a second aspect of the present invention, in the first aspect of the present invention, the three-dimensional braiding is formed such that the cross-sectional shape on the other end side is larger than the one end side in the portions of the both side frames. Yes. Therefore, in this invention, it is preferable from the point of intensity | strength and a material usage-amount compared with the case where the cross-sectional area of a side frame is made constant. In addition, it is easy to partially change the cross-sectional area of the side frame for three-dimensional braiding.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the three-dimensional braiding is formed in a cylindrical shape. Therefore, in the present invention, the three-dimensional braiding has a structure that is seamless in the circumferential direction, so that the strength of the fiber-reinforced composite material can be increased.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the three-dimensional braiding is formed such that the circumferential length monotonously increases from the minimum circumferential length portion toward both ends. Here, the “minimum circumference portion” means a place where the circumference is the shortest. Therefore, in the present invention, the three-dimensional braiding includes a shape in which the circumferential length gradually increases from the minimum circumferential length portion toward both ends, a shape having the minimum circumferential length portion, a circumferential length longer than that, and a constant circumferential length portion, It is formed in a shape whose length changes stepwise. Therefore, by using a mandrel that can be divided at the minimum circumference portion, a three-dimensional braiding that does not have a constant cross section can be easily created.

  The invention according to claim 5 is a three-dimensional braiding forming step of forming a three-dimensional braiding by winding a yarn around the mandrel using a three-dimensional braiding device, and the formed three-dimensional braiding The mandrel removing step for removing the mandrel from the inside of the sheet, the three-dimensional braiding pressing step for crushing the three-dimensional braid from which the mandrel has been removed to form the skeleton shape of the seat frame, and the three-dimensional skeleton shape of the seat frame A resin impregnating and curing step of impregnating and curing the resin in the braiding. Here, the “yarn” means a fiber bundle in which fibers are arranged without being twisted or a twisted yarn.

  In this invention, when forming a three-dimensional braiding, a thread is wound around the outside using a mandrel, so that a cylindrical three-dimensional braiding having a diameter that changes midway can be easily formed. In addition, the cylindrical three-dimensional braiding is crushed to match the skeleton shape of the seat frame, so it is easier than forming a cylindrical three-dimensional braiding of the desired shape from the beginning and impregnating and curing the resin. A fiber reinforced composite material can be formed.

  According to the present invention, the productivity and strength of a seat frame made of a fiber reinforced composite material can be improved.

(A) is a schematic perspective view of the seat frame of 1st Embodiment, (b) is sectional drawing in the AA of (a), (c) is the partial schematic diagram of the structure | tissue state of three-dimensional braiding. The model perspective view of a mandrel. The model perspective view which shows a seat. (A), (b) is a schematic cross section of the seat frame of 2nd Embodiment. The model perspective view of a mandrel. (A), (b) is a schematic diagram which shows the structure | tissue state of the three-dimensional braiding in another embodiment. (A) is a perspective view of the seat back frame of a prior art, (b) is sectional drawing in the BB line of (a). (A) is a perspective view of another conventional seat back frame, (b) is a cross-sectional view taken along line CC of (a). The schematic plan view explaining another prior art.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a seat frame of an automobile will be described with reference to FIGS.

  As shown in FIG. 1A, the seat frame 10 is composed of left and right side frames 11a and 11b and a connecting frame 11c that connects one end portions of both side frames 11a and 11b. The seat frame 10 is formed of a fiber-reinforced composite material including three-dimensional braiding (three-dimensional braid) extending as a reinforcing fiber extending from one side frame 11a through the connecting frame 11c to the other side frame 11b. As shown in FIG. 1B, the seat frame 10 is formed in a hollow shape. The three-dimensional braiding is formed in a cylindrical shape and is seamless in the circumferential direction. The three-dimensional braiding is formed so that the cross-sectional shape on one end side, that is, on the other end side (base end side) is larger than the side continuous with the connecting frame 11c in both side frames 11a and 11b. That is, the three-dimensional braiding is formed so that the circumference gradually increases from the minimum circumference to both ends. Here, the “minimum circumference portion” means a place where the circumference is the shortest.

  As shown in FIG. 1C, the three-dimensional braiding 12 is folded back on both sides in the thickness direction (radial direction) of the three-dimensional braiding 12 and has a predetermined orientation angle in the longitudinal direction of the three-dimensional braiding 12. It is composed of a large number of yarns 13 arranged in a row, and a plurality of yarns 14 arranged along the longitudinal direction of the three-dimensional braiding 12, that is, with an orientation angle of 0 °. Therefore, the cut ends of the yarns 13 and 14 constituting the three-dimensional braiding 12 are not exposed at the end portions in the thickness direction. The orientation angle is an angle formed with the longitudinal direction of the three-dimensional braiding 12, and the value is appropriately set in a range of ± 10 ° to 80 °, for example, but in a portion where the diameter of the three-dimensional braiding 12 is large. It is set large and small in the small diameter part.

  As the yarns 13 and 14, for example, carbon fiber fiber bundles (rovings) having a light weight, high breaking strength, and a large elastic modulus are used. Further, as the matrix resin of the fiber reinforced composite material, a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, or a vinyl ester resin is used.

  Next, a method for manufacturing the seat frame configured as described above will be described. The seat frame manufacturing method includes a three-dimensional braiding forming step, a mandrel removing step, and a resin impregnation curing step. In the three-dimensional braiding forming process, a three-dimensional braiding apparatus is used to form a three-dimensional braiding by winding a yarn around the mandrel.

  In the three-dimensional braiding forming step, as a three-dimensional braiding apparatus, for example, a three-dimensional braider (rotor carrier type three-dimensional weaving loom) disclosed in Japanese Patent Publication No. 3-64619, Japanese Patent Publication No. 4-13463, and the like. ) Is used. Then, using a mandrel 15 as shown in FIG. 2 having the shape of the hollow portion of the three-dimensional braiding to be formed, a braid structure is formed in a state where the yarns 13 and 14 are wound around the outside of the mandrel 15. . The mandrel 15 is formed in a shape in which a wide portion 15b whose width changes corresponding to the side frames 11a and 11b continuously extends linearly at both ends of the narrow portion 15a corresponding to the connecting frame 11c. This part is formed so as to be split into two. Then, a screw hole is formed in one narrow portion 15a, and a through hole through which a shaft portion of a bolt having a male screw portion screwed into the screw hole is inserted is formed in the other narrow portion 15a. Yes.

  In the mandrel removing step, the three-dimensional braiding formed in the three-dimensional braiding forming step is removed from the three-dimensional braiding apparatus together with the mandrel 15. Then, the bolt connecting the mandrel 15 is removed, and the mandrel 15 is removed from the inside of the three-dimensional braiding. Since the three-dimensional braiding is formed in a straight state corresponding to the shape of the mandrel 15, the base frames of the side frames 11 a and 11 b and the connecting frame 11 c are formed into a shape of the seat frame 10. After being bent together, the thermosetting resin is impregnated and cured in a resin impregnation and curing step.

  In the resin impregnation curing step, the three-dimensional braiding is impregnated with the thermosetting resin by the RTM method and is thermoset. In order to prevent the resin from filling the inside of the 3D braiding, the 3D braiding is filled with beads that are easy to take out and filled in the mold with both ends closed with lids. Be placed. Then, after thermosetting, the mold is opened and the seat frame 10 integrally formed with the fiber reinforced composite material is taken out, and the lid and beads are taken out from the inside of the three-dimensional braiding, and the manufacture of the seat frame 10 is completed. .

  As shown in FIG. 3, the seat frame 10 is connected to a seat frame 17 for a seat constituting the seat of the seat 16 via a connecting shaft 18 or a bolt (not shown). Therefore, a hole through which the connecting shaft 18 or the bolt is inserted is formed in the seat frame 10. The holes may be formed after the seat frame 10 is manufactured, but may be formed before the three-dimensional braiding is impregnated with the thermosetting resin. For example, a three-dimensional braiding is placed in a mold for impregnation and curing with a perforated member inserted through a portion where a three-dimensional braiding hole is to be formed, and impregnation and curing of a thermosetting resin is performed. Also good.

According to this embodiment, the following effects can be obtained.
(1) The seat frame 10 includes a left and right side frames 11a and 11b and a connecting frame 11c that connects between one end portions of the side frames 11a and 11b, and the other side through the connecting frame 11c from one side frame 11a. It is formed of a fiber reinforced composite material provided with three-dimensional braiding extending over the frame 11b as reinforcing fibers. Therefore, productivity is improved as compared with the case where a plurality of prepregs are stacked. Further, the strength is improved as compared with the case where prepregs are laminated, planar woven fabrics are laminated as reinforcing fibers, or fibers are simply arranged.

  (2) The three-dimensional braiding is formed so that the cross-sectional shape on the other end side (base end side) is larger than the one end side (tip end side) in both side frames 11a and 11b. Therefore, it is preferable in terms of strength and material usage as compared with the case where the cross-sectional areas of the side frames 11a and 11b are constant. Further, because of the three-dimensional braiding, it is easy to partially change the cross-sectional areas of the side frames 11a and 11b in a state where the reinforcing fibers are continuous.

  (3) In the three-dimensional braiding 12, the yarns 13 arranged so as to obliquely intersect the longitudinal direction of the three-dimensional braiding 12 are folded back on both sides in the thickness direction (radial direction) of the three-dimensional braiding. Thus, the cut surfaces of the yarns 13 do not exist on both sides in the thickness direction of the three-dimensional braiding. Therefore, even if bending stress is applied to the seat frame 10, it is difficult to break from the surface in the thickness direction of the three-dimensional braiding, and the seat frame using a conventional laminated fiber as a reinforcing material, that is, simply laminated fiber woven fabric or nonwoven fabric The durability is improved compared to a seat frame impregnated and cured with resin. In addition, there is no layer that can be clearly divided in a plane orthogonal to the thickness direction of the fiber reinforced composite material constituting the seat frame 10, and even if bending stress is repeatedly applied to the seat frame 10, a conventional planar fabric Unlike those obtained by laminating and reinforcing materials, delamination hardly occurs and durability is improved.

  (4) The seat frame 10 is formed in a hollow shape, and the three-dimensional braiding 12 is formed in a cylindrical shape, and is used as a reinforcing fiber in a state where there is no seam in the circumferential direction. Therefore, the bending strength of the seat frame 10 is improved as compared with a solid body having the same weight and a similar outer shape. Also, the operation of bending the three-dimensional braiding 12 into the shape of the seat frame 10 is easier than in the case where the three-dimensional braiding 12 is solid.

  (5) Since carbon fibers are used as the yarns 13 and 14 constituting the reinforcing fibers, the weight of the seat frame 10 having the same strength as compared with a conventional iron seat frame should be reduced. If the seat frame 10 has the same weight, the strength can be improved.

  (6) The three-dimensional braiding 12 is formed so that the circumference gradually increases from the minimum circumference to both ends. Therefore, by using the mandrel 15 that can be divided at the minimum circumference portion, it is possible to easily create the three-dimensional braiding 12 that does not have a constant cross section.

  (7) The manufacturing method of the seat frame 10 includes a three-dimensional braiding forming step of forming a three-dimensional braiding by winding the yarns 13 and 14 around the mandrel 15 using a three-dimensional braiding device, A mandrel removing step of removing the mandrel 15 from the inside of the three-dimensional braiding. Accordingly, it is possible to easily form a cylindrical three-dimensional braiding whose thickness changes midway.

  (8) Impregnation and curing of the thermosetting resin to the formed three-dimensional braiding is performed by the RTM method. Therefore, it is easy to cure in a state where the thermosetting resin is uniformly impregnated between the reinforcing fibers of the three-dimensional braiding.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. This embodiment is different from the first embodiment in that the seat frame 10 is not hollow but formed in a solid body. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The seat frame 10 is formed in a U-shaped cross section as shown in FIG. 4A or a hat shape in cross section as shown in FIG. The three-dimensional braiding 12 having such a cross-sectional shape is formed by crushing a cylindrical three-dimensional braiding so that the inner surface is in close contact with each other and has a corresponding cross-sectional shape. In FIG. 4A and FIG. 4B, hatching representing a cross section is omitted.

  The manufacturing method of the seat frame 10 in this embodiment includes a three-dimensional braiding forming process, a mandrel removing process, a three-dimensional braiding pressing process, and a resin impregnation curing process. That is, a three-dimensional braiding pressing step is provided between the mandrel removing step and the resin impregnation curing step in the manufacturing method of the first embodiment.

  In the three-dimensional braiding forming step, as shown in FIG. 5, a three-dimensional braiding 12 is formed using a mandrel 19 having a circular cross section and a shape in which a large diameter portion 19a provided on both sides is connected by a small diameter portion 19b. The The mandrel 19 is formed so as to be divisible by the small diameter portion 19 b and is connected by a bolt (not shown) like the mandrel 15. In the three-dimensional braiding pressing step, the three-dimensional braiding from which the mandrel 19 has been removed in the mandrel removing step is bent in accordance with the outer shape of the seat frame 10, and then crushed into the skeleton shape of the seat frame 10, or Bending is performed while crushing to obtain a skeleton shape of the seat frame 10. In the resin impregnation curing step, the resin is impregnated and cured in the three-dimensional braiding 12 having a skeleton shape of the seat frame 10.

According to the second embodiment, the following effects can be obtained in addition to the effects (1) to (3), (5), and (8) of the first embodiment.
(9) Since the seat frame 10 is formed in a U-shaped cross-section or a hat-like cross section, unlike the hollow case, the three-dimensional braiding 12 as the reinforcing fiber is hollow when impregnated with a thermosetting resin. The work of preventing the portion from being buried becomes unnecessary, and the impregnation hardening process is simplified.

  (10) Since the three-dimensional braiding 12 is formed in a cylindrical shape having a circular cross section, the three-dimensional braiding 12 is bent in accordance with the formation of the three-dimensional braiding 12 and the outer shape of the seat frame 10 as compared with a case where the cross section is a substantially square cylindrical shape. Work becomes easier and productivity is improved.

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ Instead of using only carbon fiber as the yarns 13 and 14 constituting the three-dimensional braiding 12, some yarns 13 and 14 are made of carbon fiber, and other yarns 13 and 14 are aramid. It may be made of a high-strength, high-elasticity organic fiber such as fiber, PBO fiber (polyparaphenylene / benzobis / oxazole fiber), or ultrahigh molecular weight polyethylene fiber. Alternatively, the yarn 14 having an orientation angle of 0 ° may be made of carbon fiber, and the yarn 13 may be made of organic fiber. Carbon fiber is lightweight and has high strength, but is susceptible to brittle fracture. However, when the three-dimensional braiding 12 is formed by mixing the yarns 13 and 14 with a high-strength and high-elasticity organic fiber and a carbon fiber, brittle fracture is less likely to occur. Therefore, the entire cross section does not break at a stretch with respect to the collision load, and the energy absorption is large and the safety is further improved.

  The matrix resin constituting the fiber reinforced composite material is not limited to a thermosetting resin, and for example, a thermoplastic resin such as polyamide, polybutylene terephthalate, polycarbonate, polyoxymethylene, polyphenylene ether or the like may be used. Thermosetting resin is preferable to thermoplastic resin in terms of strength, but thermoplastic resin is superior to thermosetting resin in terms of toughness, and the entire cross section does not break at a stretch with respect to impact load, and energy absorption is achieved. The safety is greatly improved. Of these, polyamide is preferable in terms of moldability, mechanical properties, and cost.

  ○ As shown in FIG. 6A, the structure of the three-dimensional braiding 12 is such that the yarns 13 arranged obliquely with respect to the longitudinal direction of the three-dimensional braiding 12 are in the thickness direction of the three-dimensional braiding 12. For example, as shown in FIG. 6B, the yarns 13 are arranged so as to be folded over a plurality of layers, for example, as shown in FIG. That's fine. However, in FIGS. 6A and 6B, for convenience of illustration, the yarns 13 are drawn so as to be folded back on the same plane, but are not actually arranged on the same plane.

  ○ As the three-dimensional braiding, a structure in which a plurality of planar braid structures (two-dimensional braiding) are stacked and the both ends are integrally coupled may be used. In short, it is only necessary that the three-dimensional braiding is formed by the braiding apparatus so as to have a three-dimensional structure or a structure in which a plurality of two-dimensional braidings are integrally coupled. Also in this case, the productivity is higher than that in which the woven fabric is laminated and the resin is impregnated.

  ○ When the seat frame 10 is formed in a hollow shape as in the first embodiment, the three-dimensional braiding 12 is not limited to a substantially rectangular cross section, but may be other polygonal cross sectional shapes, circular cross sectional shapes, or elliptical cross sectional shapes. Good. Further, after forming the cylindrical three-dimensional braiding 12 having a circular cross section using the circular mandrel 19, the cross sectional shape is changed by pressing the three-dimensional braiding 12 from which the mandrel 19 is removed. May be.

  ○ Cylindrical three-dimensional braiding that can be easily created by using a mandrel that can be divided at the minimum circumference, is not limited to a shape that gradually increases from the minimum circumference to both ends, but from the minimum circumference to both ends. Any shape that monotonously increases toward the surface may be used. For example, a shape including a minimum peripheral length portion and a peripheral length portion having a longer peripheral length and a constant peripheral length, a shape in which the peripheral length changes stepwise, and the like can be mentioned.

  In the case of forming the three-dimensional braiding 12 bent in a substantially U shape so as to correspond to the outer shape of the seat frame 10, the method is not limited to the method of bending after forming the straight three-dimensional braiding 12. For example, when forming the three-dimensional braiding 12 with the three-dimensional braiding apparatus, the mandrel bent according to the outer shape of the seat frame 10 is used, and the three-dimensional braiding 12 bent in the same manner as the outer shape of the seat frame 10. May be formed. In this case, a method of removing the mandrel by using a mandrel of a material suitable for melting and melting the mandrel after forming the three-dimensional braiding can be considered. Further, a three-dimensional braiding 12 having a small degree of bending is first formed using a bent mandrel with a bending degree smaller than that of the seat frame 10, and then bent so that the bending degree matches the seat frame 10. It may be formed.

A resin impregnation hardening mold may be used instead of a dedicated mold for crushing the cylindrical three-dimensional braiding 12 into a U-shaped cross section or a hat shape.
The present invention is not limited to the seat frame 10 for the back portion of the seat 16 and may be applied to, for example, a seat frame 17 for a seat as shown in FIG. The seat frame 17 is composed of both side frames 17a and 17b and a connecting frame 17c that connects one end of the side frames 17a and 17b.

○ The present invention is not limited to a seat frame of an automobile, and may be applied to a seat frame of a seat such as an aircraft or a ship.
The three-dimensional braiding 12 may be formed of only the yarns 13 arranged so as to extend obliquely with respect to the longitudinal direction without the yarns 14 extending at an arrangement angle of 0 ° along the longitudinal direction. However, the strength against bending and pulling increases when the yarn 14 having an arrangement angle of 0 ° exists.

  ○ The three-dimensional braiding 12 may be formed by combining yarns 13 and 14 having different thicknesses in place of the yarns 13 and 14 having the same thickness. In these cases, it becomes easy to adjust the strength and rigidity of the fiber-reinforced composite material.

The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to claim 1 or 2, the three-dimensional braiding is crushed into a U-shaped cross section or a cross-sectional hat shape so that the inner surface of the cylindrical three-dimensional braiding is in close contact with each other. It is used as a reinforcing fiber in the state.

  DESCRIPTION OF SYMBOLS 10 ... Seat frame, 11a, 11b, 17a, 17b ... Side frame, 11c, 17c ... Connection frame, 12 ... Three-dimensional braiding, 13, 14 ... Yarn, 15, 19 ... Mandrel.

Claims (5)

  A fiber having a three-dimensional braiding as a reinforcing fiber, wherein left and right side frames and a connecting frame connecting between one end portions of both side frames extend from one side frame to the other side frame through the connecting frame. A seat frame formed of a reinforced composite material.   2. The seat frame according to claim 1, wherein the three-dimensional braiding is formed such that a cross-sectional shape on the other end side is larger than the one end side in the both side frame portions.   The seat frame according to claim 1 or 2, wherein the three-dimensional braiding is formed in a cylindrical shape.   4. The seat frame according to claim 3, wherein the three-dimensional braiding is formed such that a circumference increases monotonously from a minimum circumference to both ends.   A three-dimensional braiding forming step of forming a three-dimensional braiding by winding a yarn around the mandrel using a three-dimensional braiding device, and a mandrel for removing the mandrel from the inside of the formed three-dimensional braiding A removing step, a three-dimensional braiding pressing step that crushes the three-dimensional braid from which the mandrels have been removed to form a skeleton shape of the seat frame, and a resin that impregnates and cures the three-dimensional braid that has the skeleton shape of the seat frame. A method for producing a seat frame, comprising: an impregnation curing step.

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