Molded structure and method for producing the same

Abstract

To provide a molded structure that can secure rigidity of an end part even in a case where the number of times of heat processing is reduced, and a manufacturing method of the molded structure.SOLUTION: A molded structure 1, being plate-shaped and including fibers and thermoplastic resin, includes a body part 11 configured of a main body part being a plate-shaped body and a rising part 12 formed such that at least part of a peripheral part of the plate-shaped body is bent and rising from the body part 11. A groove part 16 being groove-shaped and extending in a direction along an end peripheral part of the rising part 12 is arranged in an inside face 10B of the rising part 12, and the groove part 16 is filled with a rear side charged part 23 consisting of the thermoplastic resin.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a molded structure and a method for manufacturing a molded structure. [Background technology]

[0002] Conventionally, a known method for producing a molded structure is described in Patent Document 1. Patent Document 1 describes a method for producing a vehicle interior material (base material) by heating and cooling a thermoforming fiberboard formed into a mat shape from a blend of resin fibers and plant fibers to produce a preboard, reheating the preboard to a temperature at which the resin melts, and then press-molding the preboard using upper and lower dies for cold press molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-179716 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method of the molded structure disclosed in Patent Document 1, the heat treatment is performed twice, when the pre-board is made and when the base material is molded, which increases the processing cost, lengthens the cycle time, and increases the manufacturing cost. In addition, during the heat treatment, the pre-board emits a peculiar odor and volatile organic compounds in the pre-board are generated, which is unfriendly to the environment.

[0005] In order to solve this problem, it is conceivable to reduce the number of times the heating process is performed, but if the process of reheating the preboard during molding of the substrate is omitted, the preboard (substrate) becomes hard and difficult to stretch. Furthermore, when cutting the end portions of such a hard and difficult to stretch preboard while bending it during substrate molding, the shear blade for cutting provided on the molding die slides against the surface of the preboard and damages it, which raises concerns that the end portions of the completed substrate will become partially thin and its rigidity will decrease.

[0006] The technology disclosed in this specification was developed based on the above-mentioned circumstances, and aims to provide a molded structure and a method for manufacturing a molded structure that can ensure the rigidity of the terminal portions even when the number of heat treatments is reduced. [Means for solving the problem]

[0007] The technology disclosed in this specification is a plate-shaped molded structure containing fibers and thermoplastic resin, and has a main body consisting of a main portion of a plate-shaped body, and a rising portion formed by bending at least a portion of the peripheral portion of the plate-shaped body and rising from the main body portion, wherein a groove-shaped groove portion extending in a direction along the edge portion of the rising portion is provided on the inner surface of the rising portion, and thermoplastic resin is filled in the groove portion.

[0008] According to the above-mentioned configuration, the thermoplastic resin filled in the groove extending in the direction along the edge of the rising portion acts as a reinforcing portion, so that the rigidity of the rising portion can be increased. Therefore, when manufacturing a molded structure, for example, when at least a part of the peripheral portion of the main body is bent by press molding to form the rising portion, when the tip portion is cut with a shear blade, the periphery of the tip portion is damaged by the shear blade and the plate thickness of that portion is reduced, so that the rigidity of the rising portion can be ensured. In particular, when the plate material to be molded is hard and difficult to deform, such as when heating before press molding is omitted for cost reduction, the plate material is easily damaged by the shear blade, so the effect of this configuration can be remarkable.

[0009] The groove may be a V-groove having a V-shaped cross section. When the groove is a V-groove, it is easier to maintain the strength of the surface opposite to the surface on which the groove is provided when the thermoplastic resin is not filled in the groove during the production of the molded structure, compared to when the groove is a rectangular or U-shaped cross section.

[0010] A groove-shaped bend portion groove portion may be provided on the outer surface of the bend portion, which is the portion where at least a portion of the peripheral edge of the plate-like body is bent to raise the rising portion, and a thermoplastic resin may be filled in the bend portion groove portion.

[0011] According to the above-mentioned configuration, the strength of the bent portion, which has been thinned by the bent portion side groove, can be improved by the thermoplastic resin filled in the bent portion side groove. Also, the bent shape of the molded structure can be maintained by the thermoplastic resin filled in the bent portion side groove.

[0012] The resin filled in the bent portion side groove may be made of the same thermoplastic resin as the resin filled in the groove.

[0013] According to the above-mentioned configuration, when manufacturing the molded structure, molten resin can be injected into the groove and simultaneously filled into the bent portion side groove.

[0014] A molded body made of a thermoplastic resin may be provided integrally, and the molded body may be made of the same thermoplastic resin as the resin filled in the groove portion.

[0015] According to the above-mentioned configuration, when manufacturing the molded structure, the molded body to be provided in the main body can be injection molded at the same time as the molten resin is injected into the groove.

[0016] In addition, the technology disclosed in this specification is a method for producing a molded structure, which sequentially includes a pre-board molding process in which a mat containing fibers and thermoplastic resin is hot-pressed using a press mold to mold a pre-board; a cutting process in which groove-shaped groove portions are formed at predetermined locations on the plate surface of the pre-board; a press molding process in which the pre-board is pressed using a molding mold at a temperature at which the thermoplastic resin does not melt, to mold a base material having a main body portion constituted by the main portion of a plate-like body and a rising portion that rises from the main body portion with the groove portion disposed on the inner side by bending at least a portion of the peripheral portion of the plate-like body; and a resin filling process in which thermoplastic resin is filled into the groove portion.

[0017] According to the above-mentioned manufacturing method, even if the pre-board is not heated during press molding of the molded structure and the surface of the rising portion is scraped off by a shear blade for cutting the ends provided on the mold, causing a loss of rigidity, the thermoplastic resin in the groove extending in the direction along the edge of the rising portion acts as a reinforcing portion. That is, the rigidity of the rising portion can be increased by the thermoplastic resin filled in the groove.

[0018] In the cutting process, a notch may be formed in a predetermined location on the surface of the pre-board opposite to the surface on which the groove portion is formed, and in the press molding process, the pre-board may be folded along the notch to form a groove-shaped bent portion side groove portion on the outer surface of the bent portion, which is the folded part, where the notch is opened, and in the resin filling process, the bent portion side groove portion may be filled with the same thermoplastic resin as the resin filled in the groove portion.

[0019] According to the above configuration, even if the pre-board is not heated during press molding of the molded structure, by providing a groove in advance on the surface that will become the outer surface of the bent portion, the groove opens during press molding of the pre-board to form the bent portion groove at a predetermined position. In other words, the pre-board is prevented from cracking or breaking at any position other than the predetermined position. In addition, the bent shape of the molded structure is maintained by filling the bent portion groove with thermoplastic resin.

[0020] In the resin filling step, the thermoplastic resin may be filled into the bent portion groove portion from an inside of the bent portion.

[0021] According to the above manufacturing method, no injection port marks are left on the outer periphery of the bent portion side groove portion, and the outer periphery can be beautifully formed.

[0022] The method may include a molded body molding step of injection molding a molded body made of the same thermoplastic resin as the resin filled in the groove, and the molded body molding step may be performed simultaneously with the resin filling step.

[0023] According to the above-mentioned manufacturing method, the grooves can be filled and the molded body can be injection molded at the same time. Effect of the Invention

[0024] According to the technology disclosed in this specification, it is possible to provide a molded structure and a method for manufacturing a molded structure that can ensure the rigidity of the terminal portions even when the number of heat treatments is reduced. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view showing a seat back board according to an embodiment of the present invention as viewed from the front side; [Diagram 2] Rear view of the seat backboard [Diagram 3] FIG. 2 is a partially enlarged perspective view showing the seat back board as viewed from the back side; [Figure 4] FIG. 1 is a cross-sectional view illustrating a state in which a fiber mat is being pressed by a press mold, for explaining a pre-board molding process. [Diagram 5] FIG. 13 is a partially enlarged cross-sectional view illustrating the cutting step, showing the pre-board after it has been cut. [Figure 6] A partially enlarged cross-sectional view showing the molding device and the pre-board before the pre-board is placed on the lower die (with the upper and lower dies in an open state) [Figure 7]FIG. 1 is a partially enlarged cross-sectional view illustrating a press molding process, showing a state in which the mold of the molding device is being closed. [Figure 8] FIG. 1 is a diagram for explaining a press molding process, and is a partially enlarged cross-sectional view showing a state in which the mold of the molding device is closed and an end of the base material is cut off. [Figure 9] FIG. 9 is a partially enlarged cross-sectional view for explaining a resin filling step, showing a state in which molten resin is injected from the state shown in FIG. 8; [Figure 10] FIG. 10 is a cross-sectional view showing a state in which the upper and lower dies of the molding device are opened from the state shown in FIG. 9 to complete the seat back board. [Figure 11] A graph showing the cross-sectional area, shape, and formation position of the rear groove portion and the change in the displacement amount of the seat back board [Figure 12] FIG. 13 is a partially enlarged cross-sectional view of a modified seat back board; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment will be described with reference to Figs. 1 to 11. The molded structure and the manufacturing method of the molded structure of this embodiment are adopted in a seat backboard 1 constituting a vehicle seat such as an automobile. More specifically, the vehicle seat includes a seat cushion and a seat back, and the seat backboard 1 constitutes the back surface of the seat back. Note that some of the drawings show the X-axis, Y-axis, and Z-axis, and each axial direction is drawn to be the direction shown in each drawing. The front-back direction is based on Fig. 1, and the upper side of Fig. 1 is the front side, and the lower side is the back side. In addition, the vertical direction is described in Figs. 1 to 3 as the Y direction based on the seat backboard 1, and in Figs. 6 to 10 as the Z direction based on the molding device 40. Furthermore, for multiple identical parts, a reference symbol may be attached to one part, and the reference symbols may be omitted for other parts.

[0027] As shown in the perspective view of Fig. 1, the seat back board 1 has a generally rectangular shallow dish shape. The seat back board 1 is configured to include a plate-shaped base material 10 and a resin part 20 (described later) provided at a predetermined part of the base material 10. Each part will be described in detail below.

[0028] The base material 10 is a flat, approximately rectangular plate-like body whose peripheral edge is bent so as to rise obliquely toward the rear and outside. Hereinafter, the central flat portion of the base material 10, which is the main portion of the seat backboard 1, will be referred to as a main body portion 11, and the portion that is bent and rises from the main body portion 11 will be referred to as a rising portion 12. In addition, the boundary portion (bent portion) between the main body portion 11 and the rising portion 12 will be referred to as a bending portion 13.

[0029] The main body 11 has a rectangular plate shape in a plan view. The dimension of the main body 11 in the vertical direction (Y direction) is slightly larger than the dimension in the horizontal direction (X direction). The rising portion 12 is provided over the entire peripheral portion of the main body 11.

[0030] In the base material 10, a front V groove (an example of a groove portion of a bent portion) 15 having a V-shaped cross section is formed on the outer surface (front surface 10A) of the bent portion 13 over the entire bent portion 13 (see FIG. 3). In other words, the front V groove 15 extends along the bent portion 13. Also, on the inner surface (back surface 10B) of the rising portion 12, a back V groove (an example of a groove portion and a V groove) 16 having a V-shaped cross section that extends along the edge portion is formed over the entire periphery in a portion adjacent to the edge portion of the tip side (opposite the main body portion 11) of the rising portion 12.

[0031] The above-mentioned substrate 10 contains fibers and a thermoplastic resin. For example, kenaf fibers are used as the fibers contained in the substrate 10, but the type of fibers is not limited thereto. Fibers used in the substrate 10 may be wood fibers, thermoplastic resin fibers, glass fibers, carbon fibers, etc. Also, in the substrate 10, the fibers are bound by a thermoplastic resin as a binder. Examples of the thermoplastic resin used as a binder in the substrate 10 include polyester-based resins such as polypropylene and polyethylene.

[0032] A resin part 20 made of a thermoplastic resin is provided at a predetermined position of the base material 10. The resin part 20 includes a clip seat (an example of a molded body) 21 provided integrally with the main body part 11 adjacent to the rising part 12 on the back surface 10B of the main body part 11, a front-side filling part 22 filling the above-mentioned front-side V-groove 15, a back-side filling part 23 filling the back-side V-groove 16, and three types of ribs (a first rib 24, a second rib 25, and a third rib 26) described later that are formed on the back surface 10B of the base material 10 (see Figs. 1 to 3).

[0033] The clip seat 21 is formed to protrude from the back surface 10B of the main body 11 of the base material 10. The clip seat 21 has a semicircular shape in a plan view (see FIG. 2), and a clip is fitted from the center of the main body 11 toward the outside. The clip seat 21 is formed of, for example, polypropylene, which is a thermoplastic resin.

[0034] The above-mentioned front-side filling portion 22 and rear-side filling portion 23 both extend around the entire periphery of the seat backboard 1, filling the V-grooves (front-side V-groove 15 and rear-side V-groove 16). The front-side filling portion 22 and rear-side filling portion 23 are formed of, for example, polypropylene, which is a thermoplastic resin.

[0035] The above-mentioned first rib 24 is provided over the entire inside (rear surface 10B) of the bent portion 13. In other words, the first rib 24 is annular. In addition, a plurality of second ribs 25 are provided so as to connect between the rear filling portion 23 and the first rib 24, and the third rib 26 is provided so as to connect between the clip seat 21 and the first rib 24 (see FIG. 2).

[0036] As described later, the first rib 24 is formed by cooling the molten resin filled in the first runner 64 provided in the molding die 50 to allow the molten resin to flow (the trace of the first runner 64). The second rib 25 is formed by cooling the molten resin filled in the second runner 65 provided in the molding die 50 to allow the molten resin to flow when filling the back side V groove 16 (the trace of the second runner 65). The third rib 26 is formed by cooling the molten resin filled in the third runner (not shown) provided in the molding die 50 to allow the molten resin to flow when molding the clip seat 21 (the trace of the third runner).

[0037] The first rib 24, the second rib 25, and the third rib 26 are formed from, for example, polypropylene, which is a thermoplastic resin.

[0038] The seat backboard 1 has the above-mentioned configuration, and next, a description will be given of a manufacturing device for manufacturing the seat backboard 1. The manufacturing device for the seat backboard 1 is roughly divided into press dies 30, 31 for producing a preboard 10P by heating and pressing a fiber mat 10F made of vegetable fibers and a thermoplastic resin, and a molding device 40 for press-molding the preboard 10P cut by a cutting device into a product shape.

[0039] The pair of press dies 30, 31 shown in Fig. 4 are configured to be mutually closed and opened by a driving device (e.g., an electric motor, an air cylinder, a hydraulic cylinder, etc.) not shown. The pair of press dies 30, 31 (press plates, hot plates) are equipped with a heating means such as a heater that generates heat when electricity is applied. As a result, the press dies 30, 31 are configured to be heated to a predetermined temperature, and the fiber mat 10F can be hot-pressed. Note that such a heater may be provided in only one of the press dies 30, 31.

[0040] 6, the molding device 40 includes an injection device 41 and a molding die 50 (upper die 51 and lower die 61). The injection device 41 is, for example, a screw type, and is provided in the lower die 61 in this embodiment.

[0041] The upper mold 51 is a movable mold that can be moved relative to the lower mold 61 (fixed mold) by a driving device (not shown, for example, an electric motor, an air cylinder, a hydraulic cylinder, etc.). The upper mold 51 and the lower mold 61 can be closed and opened by moving the upper mold 51 toward and away from the lower mold 61 in a vertical direction.

[0042] The lower die 61 has a shape in which a die surface 61A, which is a surface facing the upper die 51, protrudes toward the upper die 51. In addition, the upper die 51 has a shape in which a die surface 51A, which is a surface facing the lower die 61, is recessed corresponding to the shape of the lower die 61. As shown in FIG. 8 and other figures, in a closed state in which the upper die 51 and the lower die 61 are closed, the upper die 51 is disposed opposite the lower die 61 at a distance equal to the plate thickness of the substrate 10. That is, in the closed state, a substrate molding space S1 for molding the substrate 10 is formed between the upper die 51 and the lower die 61. As a result, when the pre-board 10P is pressed by the upper die 51 and the lower die 61, the pre-board 10P is compressed into a shape corresponding to the shape of the substrate molding space S1, and the substrate 10 is molded.

[0043] The thickness of the base material 10, i.e., the distance between the upper die 51 and the lower die 61 in the closed state, is smaller than the thickness of the pre-board 10P. In this embodiment, the thickness of the base material is set to 3 mm.

[0044] The peripheral edge of the above-mentioned substrate molding space S1 is closed by an upper closing surface 51B extending vertically downward from the mold surface 51A of the upper mold 51 and a lower closing surface 61B extending vertically downward from the mold surface 61A of the lower mold 61 sliding and overlapping with each other. A shear blade (not shown) is provided at the lower end of the upper closing surface 51B for cutting the pre-board 10P to a predetermined size when pressing the pre-board 10P (when closing the molds), and during the process of closing the upper mold 51 and the lower mold 61, the shear blade comes into contact with the upper surface of the pre-board 10P to press and deform the pre-board 10P downward, and cuts the end of the pre-board 10P as it slides against the lower closing surface 61B (see Figures 7 and 8).

[0045] A clip seat molding recess (not shown) for molding the above-mentioned clip seat 21 is recessed to open to the outside on the mold surface 61A of the lower mold 61. The lower mold 61 also includes a slide mechanism (not shown) for molding the clip seat 21.

[0046] Further, on the die surface 61A of the lower die 61, a first runner 64, a second runner 65, and a third runner (not shown) that open to the outside are formed.

[0047] The first runner 64 is provided around the mold surface 61A by cutting out an upper corner of the mold surface 61A protruding upward from the lower mold 61 in an L-shape (see FIG. 6). This first runner 64 is formed at a position corresponding to the bent portion 13 of the seat back board 1 described above. This first runner 64 is provided with a gate 42 which is an injection port through which the resin is injected from the injection device 41 (see FIG. 6).

[0048] The second runner 65 extends in a direction intersecting the extending direction of the first runner 64 by cutting out a groove-like portion of the inclined rising portion (a portion corresponding to the rising portion 12) of the mold surface 61A protruding upward from the lower mold 61 (see FIG. 6). This second runner 65 is capable of connecting between the back side V groove 16 of the press-molded base material 10 and the first runner 64 when the mold is closed, and a plurality of second runners 65 are formed.

[0049] Moreover, the third runner (not shown) extends in a direction intersecting the extending direction of the first runner 64 by cutting out a groove in the horizontally extending upper surface (the portion corresponding to the main body portion 11) of the mold surface 61A of the lower mold 61. This third runner is formed so as to connect between the first runner 64 and a clip seat molding recess (not shown) provided in the lower mold 61 for molding the above-mentioned clip seat 21.

[0050] Next, an example of a manufacturing method of the seat backboard 1 constituting a vehicle seat will be described. The manufacturing method of the seat backboard 1 of this embodiment is carried out in the following order: a pre-board molding step for molding a pre-board 10P, a cutting step for cutting the pre-board 10P to a predetermined size and shape, making incisions 15P at predetermined locations, and forming a back V groove 16, a press molding step for pressing the pre-board 10P with an upper die 51 and a lower die 61 to mold a base material 10, and a resin part molding step (an example of a resin filling step and a molded body molding step) for filling the front V groove 15 and the back V groove 16 by injecting molten resin into the first runner 64, the second runner 65, and the third runner, and molding a clip seat 21 in a form joined to the base material 10.

[0051] <Pre-board molding process> In the pre-board molding process, as shown in Fig. 4, a fiber mat 10F made of fibers and thermoplastic resin is hot-pressed by a pair of flat press dies 30, 31. As a result, the fiber mat 10F is compressed, and the thermoplastic resin contained in the fiber mat 10F melts and mixes at the contact surface. The thermoplastic resin contained in the fiber mat 10F is then cooled and solidified to form the pre-board 10P.

[0052] <Cutting process> Next, the molded pre-board 10P is cut into a predetermined size and shape by a cutter. In this embodiment, as shown in Fig. 5, a continuous linear cut 15P is formed along the periphery at a position that will become the bent portion 13 after molding, and a back V-groove 16 having a V-shaped cross section is formed along the periphery on the outer periphery of the cut 15P. The cut 15P is formed on one side (the front side in Fig. 5) of the pre-board 10P, and the back V-groove 16 is formed on the other side (the back side in Fig. 5) of the pre-board 10P. The positions and dimensions of these are as described below.

[0053] <Press molding process> Next, the pre-board 10P at room temperature (unheated state) is positioned and placed on the lower mold 61. The pre-board 10P is placed on the lower mold 61 so that the surface with the notch 15P becomes the upper surface (front surface 10A) and the surface with the back V groove 16 becomes the lower surface (back surface 10B) (see FIG. 6).

[0054] Next, the mold 50 is closed, and the pre-board 10P is press-formed by the mold surfaces 51A, 61A of the upper mold 51 and the lower mold 61 (see Figs. 7 and 8). During this press-forming, the pre-board 10P is not heated and is therefore hard and difficult to stretch. By the press-forming, the pre-board 10P is bent along the cuts 15P to form the bent portion 13. On the outer surface (front surface) of the bent portion 13, the cuts 15P are opened to form the front side V-groove 15 having a V-shaped cross section.

[0055] Further, the peripheral edge of the pre-board 10P is cut off by a shear blade provided at the lower end of the upper closed surface 51B of the upper die 51. As a result, the pre-board 10P is shaped to match the shape of the substrate molding space S1.

[0056] 7, in the process in which the upper die 51 descends and gradually approaches the lower die 61, the lower end of the upper closed surface 51B of the upper die 51 first comes into contact with the vicinity of the peripheral edge of the pre-board 10P and presses the pre-board 10P toward the lower die 61, so that the pre-board 10P is gradually bent with the cut 15P formed in the front surface 10A as the base end. That is, the cut 15P opens to form the bent portion 13, and the front-side V-groove 15 having a V-shaped cross section is formed.

[0057] In addition, during the process of pressing and bending the pre-board 10P in this manner, the shear blade provided at the lower end of the upper closing surface 51B of the upper mold 51 rubs against the surface of the pre-board 10P in a scratching manner, which may result in damage to the surface of the pre-board 10P.

[0058] In this manner, a substrate 10 is completed, which has a plate-shaped main body 11 and a rising portion 12 rising from the periphery of the main body 11 in a manner bending at a bending portion 13. The rising portion 12 rises from the main body 11 with the above-mentioned back-side V-groove 16 disposed on the inside.

[0059] As shown in Fig. 8, when the molding die 50 is closed, a space having a triangular cross section is formed between the front V groove 15 and the mold surface 51A of the upper die 51. This space is used as a front filling part molding space S2 for molding the front filling part 22. In addition, the bottom of the front V groove 15 in this state (the deepest part of the groove) is adjacent to the back surface 10B of the substrate 10 or reaches the back surface 10B of the substrate 10. That is, in the above-mentioned cutting process, the depth dimension of the cut 15P is preset so that the bottom of the front V groove 15 formed during bending is adjacent to the back surface 10B of the substrate 10 or reaches the back surface 10B.

[0060] Furthermore, when the molding die 50 is in a closed state, a space having a triangular cross section is formed between the back side V groove 16 and the mold surface 61A of the lower die 61. This space is used as a back side filling part molding space S3 for molding the back side filling part 23. Furthermore, the distance L1 of the back side V groove 16 from the peripheral part of the rising part 12 in this state is set to 2 mm, and the opening width of the back side V groove 16 is set to 2 mm. That is, in the above-mentioned cutting process, the position where the back side V groove 16 is formed is set to be 2 mm from the peripheral part of the rising part 12 during press molding, and the opening width is set to be 2 mm.

[0061] Furthermore, when the molding die 50 is in a closed state, a clip seat molding space (not shown) is formed between the above-mentioned clip seat molding recess (not shown) of the lower die 61 and the base material 10.

[0062] <Resin part molding process> After the mold is closed, a resin part molding step (one example of a resin filling step and a molded body molding step) is performed. In the resin part molding step, in a state in which the base material 10 is pressed by the mold surface 51A of the upper mold 51 and the mold surface 61A of the lower mold 61 (in a mold closed state), the injection device 41 injects molten resin into each runner and fills each space. Specifically, the molten resin injected from the gate 42 into the first runner 64 is injected through the second runner 65 into the back side filling part molding space S3, and is also injected through the third runner into the clip seat molding space.

[0063] At this time, even if the rising portion 12 of the base material 10 is damaged or deformed by being cut by a shear blade during press molding, the rising portion 12 is pressed against the mold surface 51A of the upper mold 51 by the pressure of the molten resin filled in the back side V groove 16, and the shape is maintained and reinforced by the back side filling portion 23.

[0064] The molten resin in the first runner 64 permeates the substrate 10 from within the first runner 64 and flows into and fills the substrate 10 from the bottom of the substrate 10's V-groove 15 adjacent to the substrate 10's back surface 10B. Alternatively, the molten resin is injected into the substrate 10's V-groove 15 from the bottom of the substrate 10's V-groove 15 that has reached the back surface 10B of the substrate 10, or from a through hole that penetrates from the substrate 10's V-groove 15 to the back surface 10B, and fills the substrate 10's V-groove 15. That is, the molten resin is supplied into the substrate 10's V-groove 15 from the back surface 10B of the substrate 10 (see FIG. 9).

[0065] In this manner, the first runner 64, the second runner 65, the third runner, the front filling portion molding space S2, the back filling portion molding space S3, and the clip seat molding space are filled with molten resin.

[0066] Thereafter, the molten resin filled therein is cooled, completing the seat backboard 1 composed of the base material 10 and the resin portion 20. After the thermoplastic resin (resin portion 20) contained in the seat backboard 1 is cooled and solidified, the upper mold 51 and the lower mold 61 are opened, and the seat backboard 1 is demolded (see FIG. 10). This completes the manufacture of the seat backboard 1.

[0067] <Verification of the cross-sectional area, shape, and formation position of the rear groove, and the change in the displacement of the seat backboard> The rising portion 12 of the seat backboard 1 of the above embodiment (the rear V groove 16 is filled with thermoplastic resin (rear filling portion 23)) was pressed from the inner surface (rear surface 10B) in the direction along the main body portion 11 with a force of 70 N, and the change in the displacement amount (mm / 70 N) of the rising portion of the seat backboard was measured when the cross-sectional area, shape, and forming position of the rear groove were changed. The width dimension of the rising portion was 10 mm. The measurement results are shown in the graph of FIG.

[0068] As shown in the graph, the displacement amount was 1 mm for the conventional seat backboard without a rear groove, whereas the displacement amount for all of the seats with a rear groove was approximately 0.7 mm or less, making it clear that the rigidity of the rising part is improved by providing a groove (rear filling part).

[0069] In addition, the larger the cross-sectional area of ​​the groove, the smaller the amount of displacement tends to be. 2 It was found that no significant difference was observed within this range. The cross-sectional area can be changed by appropriately setting the groove width and groove depth, but it is preferable that the distance (thickness) from the bottom of the groove to the surface is 0.5 mm or more.

[0070] Furthermore, the distance (L1 in FIG. 8) of the opening of the groove from the peripheral end of the rising portion (the end opposite the main body portion) was 2 mm rather than 3 mm, i.e., closer to the peripheral end, the amount of displacement was smaller. In other words, it was found that the rigidity was higher closer to the peripheral end. However, if the groove is formed at a position closer to the peripheral end than 2 mm, the molten thermoplastic resin may find its way around to the surface when filling the groove with thermoplastic resin, so it is desirable to set the distance L1 from the peripheral end of the rising portion to the groove at least 2 mm.

[0071] Furthermore, the cross-sectional area of ​​the groove is 2 mm 2 No difference in the amount of displacement was observed between the V-shaped and rectangular cross sections, but the cross section area was about 4 mm 2 In the vicinity of the groove, the V-shaped cross section tends to have a slightly smaller amount of displacement. In other words, it is presumed that the V-shaped cross section has a higher rigidity. This is because in a groove with a rectangular cross section, the bottom of the groove is widely present near the surface of the base material, so that the surface side becomes weak when the thermoplastic resin is not filled in the groove during the manufacturing stage of the seat backboard 1, and is more easily cut by a shear blade than when the cross section is V-shaped. Therefore, it is considered that the shape of the groove is preferably a V-shaped cross section.

[0072] Next, the effect of the present embodiment will be described. The seat backboard 1 of the present embodiment is in the form of a plate containing fiber and thermoplastic resin, and has a main body 11 made of a main part of the plate, and a rising part 12 formed by bending at least a part of the peripheral part of the plate and rising from the main body 11. A groove-like back side V groove 16 extending in a direction along the edge part of the rising part 12 is provided on the inner surface (back side 10B) of the rising part 12, and the back side V groove is filled with thermoplastic resin.

[0073] According to the above-mentioned configuration, the thermoplastic resin filled in the rear V-groove 16 extending in the direction along the edge of the rising portion 12 acts as a reinforcing part, so that the rigidity of the rising portion 12 can be increased. Therefore, when the seat backboard 1 is manufactured, in the case where at least a part of the peripheral part of the main body part 11 is bent by press molding to form the rising portion 12, even if the periphery of the tip part is damaged by the shear blade when the tip part is cut with a shear blade and the plate thickness of that part is reduced, the rigidity of the rising portion 12 can be ensured. In particular, when the plate material to be molded is hard and difficult to deform, such as when heating before press molding is omitted for cost reduction, the plate material is easily damaged by the shear blade, so the effect of this configuration can be remarkable.

[0074] In addition, the backside V groove 16 is formed in a V-groove shape with a V-shaped cross section. When the groove portion is formed in a V-groove in this manner, it is easier to maintain the strength of the front surface 10A side in a state where the thermoplastic resin is not filled in the backside V groove 16 during the manufacturing stage of the seat back board 1, compared to when the groove portion is formed in a rectangular or U-shaped cross section. Therefore, in the process of press-molding the pre-board 10P, it is possible to prevent the pre-board 10P from being broken or bent by a shear blade at the position where the backside V groove 16 is formed.

[0075] Further, a groove-shaped front V-groove 15 is provided on the outer surface of the bent portion 13, and the front V-groove 15 is filled with a front filling portion 22 made of a thermoplastic resin.

[0076] According to the above-mentioned configuration, the strength of the bent portion 13, the plate thickness of which has been reduced by the front V groove 15, can be improved by the front filling portion 22 made of thermoplastic resin filled in the front V groove 15. In addition, the front filling portion 22 filled in the front V groove 15 can maintain the bent shape of the seat back board 1.

[0077] The resin filled in the front V-groove 15 is made of the same thermoplastic resin as the resin filled in the rear V-groove 16 .

[0078] According to the above configuration, when the seat backboard 1 is manufactured, molten resin can be injected into the rear V groove 16 and simultaneously filled into the front V groove 15.

[0079] Moreover, a clip seat 21 molded from a thermoplastic resin is provided integrally, and the clip seat 21 is made of the same thermoplastic resin as the resin filled in the rear V-groove 16 .

[0080] According to the above-mentioned configuration, when the seat backboard 1 is manufactured, the clip seat 21 provided on the main body portion 11 can be injection molded at the same time that molten resin is injected into the rear V-groove 16.

[0081] In addition, the manufacturing method for the seat backboard 1 of this embodiment sequentially includes a pre-board molding process in which a fiber mat 10F containing fibers and thermoplastic resin is hot-pressed by press dies 30, 31 to form a pre-board 10P, a cutting process in which a groove-shaped back V-groove 16 is formed at a predetermined location on the plate surface of the pre-board 10P, a press molding process in which the pre-board 10P is pressed by mold surfaces 51A, 61A of a molding die 50 at a temperature at which the thermoplastic resin does not melt to form a base material 10 having a main body portion 11 constituted by a main portion of a plate-like body and a rising portion 12 that rises from the main body portion 11 with the back V-groove 16 arranged on the inner surface by bending the peripheral portion of the main body portion 11 by bending portion 13, and a resin portion molding process (resin filling process) in which thermoplastic resin is filled into the back V-groove 16, which are carried out in that order.

[0082] According to the above manufacturing method, even if the pre-board 10P is not heated during press molding of the seat backboard 1 and the surface 10A of the rising portion 12 is scraped off by a shear blade for cutting the end provided in the mold 50, causing a loss of rigidity, the back-side filling portion 23 made of a thermoplastic resin in the back-side V-groove 16 extending in a direction along the edge of the rising portion 12 acts as a reinforcing portion. That is, the rigidity of the rising portion 12 can be increased by the back-side filling portion 23 filled in the back-side V-groove 16.

[0083] In addition, in the cutting process, notches 15P are formed at predetermined locations on the surface (surface 10A) of the pre-board 10P opposite the surface on which the back V groove 16 is formed, and in the press molding process, the pre-board 10P is folded along notches 15P to form groove-shaped front V groove 15 on the outer surface (surface 10A) of the bent portion 13 where notches 15P are opened, and in the resin part formation process, the front V groove 15 is filled with the same thermoplastic resin as the resin filled in the back V groove 16.

[0084] According to the above-mentioned configuration, even if the pre-board 10P is not heated during press molding of the seat back board 1, the notch 15P that becomes the front V groove 15 is provided in advance on the surface 10A that becomes the outer surface of the bent portion 13, so that the notch 15P opens during press molding of the pre-board 10P to form the front V groove 15 at a predetermined position. That is, the pre-board 10P is prevented from cracking or breaking at any position other than the predetermined position. In addition, the front filling portion 22 made of thermoplastic resin is filled in the front V groove 15, so that the bent shape of the seat back board 1 is maintained.

[0085] In addition, in the resin portion molding process, the thermoplastic resin is filled into the front V-groove 15 from the inside of the bent portion 13.

[0086] According to the above manufacturing method, no trace of the gate 42 of the injection device 41 is left on the outer periphery of the front V-groove 15, and the outer periphery can be beautifully molded.

[0087] The method also includes a clip seat molding step of injection molding a clip seat 21 made of the same thermoplastic resin as the resin filled in the rear V-groove 16, and the clip seat molding step is performed simultaneously with the resin portion molding step.

[0088] According to the above manufacturing method, the rear V-groove 16 is filled and the clip seat 21 is simultaneously injection molded.

[0089] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and for example, the following embodiments are also included within the technical scope.

[0090] (1) In the above embodiment, the raised portion 12 is provided over the entire outer circumferential edge of the main body 11. However, a configuration in which the raised portion is provided on only a portion of the outer circumferential edge of the main body is also included in the technical scope.

[0091] (2) The shape of the back side V groove 16 may be a groove shape having a U-shape or a rectangular cross section. Fig. 12 shows a modified example in which the back side groove portion 116 has a rectangular cross section. In this figure, the same components as those in the above embodiment except for the back side groove portion 116 are given reference numerals with 100 added to the reference numerals used in the above embodiment.

[0092] (3) In the above embodiment, the seat back board 1 is provided with the front V groove 15 and the front filling portion 22. However, the front groove portion and the front filling portion do not necessarily have to be provided.

[0093] (4) In the above embodiment, the clip seat 21 is provided on the back surface 10B of the main body 11, but a molded body other than the clip seat may be provided. Also, the molded body may be provided on the rising portion. Furthermore, a configuration in which no molded body is provided is also included in the technical scope.

[0094] (5) In the above embodiment, the front filling portion 22 and the clip seat 21 are made of the same thermoplastic resin as the back filling portion 23, but they may be made of different thermoplastic resins. [Explanation of symbols]

[0095] 1, 101: seat backboard (molded structure), 10, 110: base material, 10P: pre-board, 11, 111: main body, 12, 112: rising part, 13, 113: bending part, 15, 115: front side V groove (bending part groove part), 15P: notch, 16: back side V groove (groove part, V groove), 21: clip seat (molded body), 22, 122: front side filling part (thermoplastic resin), 23, 123: back side filling part (thermoplastic resin), 50: molding die, 116: back side groove part

Claims

1. A plate-shaped molded structure comprising fibers and a thermoplastic resin, A main body portion constituted by a main portion of a plate-like body; a rising portion formed by bending at least a portion of a peripheral portion of the plate-like body and rising from the main body portion, A groove-shaped portion is provided on an inner surface of the rising portion, the groove extending in a direction along an edge portion of the rising portion, and a thermoplastic resin is filled in the groove, a groove-shaped bent portion groove portion is provided on an outer surface of a bent portion, which is a portion where at least a part of the peripheral portion of the plate-like body is bent to raise the rising portion, A molded structure in which the bent portion side groove portion is filled with a thermoplastic resin.

2. 2. The molded structure according to claim 1, wherein the resin filled in the bent portion side groove is made of the same thermoplastic resin as the resin filled in the groove.

3. A plate-shaped molded structure comprising fibers and a thermoplastic resin, A main body portion constituted by a main portion of a plate-like body; a rising portion formed by bending at least a portion of a peripheral portion of the plate-like body and rising from the main body portion, A groove-shaped portion is provided on an inner surface of the rising portion, the groove extending in a direction along an edge portion of the rising portion, and a thermoplastic resin is filled in the groove, A molded structure comprising an integrally formed body made of a thermoplastic resin, the body being made of the same thermoplastic resin as the resin filled in the groove portion.

4. The molded structure according to claim 1 , wherein the groove portion is a V-groove having a V-shaped cross section.

5. a pre-board molding step of hot pressing a mat containing fibers and a thermoplastic resin with a press mold to form a pre-board; A cutting process for forming a groove-shaped groove portion at a predetermined location on a board surface of the preboard; a press molding process in which the pre-board is pressed with a mold at a temperature at which the thermoplastic resin does not melt to mold a base material having a main body portion constituted by a main portion of a plate-like body and a rising portion that rises from the main body portion in a manner such that the groove portion is disposed on an inner side surface by bending at least a part of a peripheral portion of the plate-like body; and a resin filling step of filling the grooves with a thermoplastic resin.

6. In the cutting step, a notch is formed at a predetermined position on a surface of the preboard opposite to a surface on which the groove portion is formed, In the press molding process, the pre-board is folded along the cuts to form groove-shaped bent portion side grooves on the outer surface of the bent portion, which is the folded portion, where the cuts are opened, The method for producing a molded structure according to claim 5 , wherein in the resin filling step, the bent portion side groove portion is filled with the same thermoplastic resin as the resin filled in the groove portion.

7. The method for producing a molded structure according to claim 6 , wherein in the resin filling step, the thermoplastic resin is filled into the bent portion side groove portion from an inside of the bent portion.

8. a molding step of injection-molding a molded body made of the same thermoplastic resin as the resin filled in the groove portion, The method for producing a molded structure according to claim 5 , wherein the molded body molding step is carried out simultaneously with the resin filling step.

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