Door inner panel manufacturing method and door inner panel

Abstract

Provided are a door inner panel manufacturing method and a door inner panel with which it is possible to ensure the mechanical strength of a side frame that extends in a vertical direction in a relatively narrow region serving as a window frame. This door inner panel manufacturing method is a method for manufacturing a door inner panel that includes a side frame which extends in a vertical direction and which is molded integrally using a composite material X including reinforcing fibers dispersed in an in-plane direction, and an injection molding material Y, the manufacturing method including the following steps (1) to (4): (1) a step for arranging the composite material X on a molding fixed die; (2) a step for lowering a molding moveable die to cause the molding moveable die to come into contact with the composite material X; (3) a step for injecting the injection molding material Y into a molding die; and (4) a step for pressing the composite material X and the injection molding material Y inside the molding die to integrally mold the door inner panel.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an automobile door inner panel, which has two side frames extending in the vertical direction and a window opening between the two side frames, and is integrally molded from a composite material and an injection molding material, and to the door inner panel. [Background technology]

[0002] An automobile door inner panel is the door panel that is located inside the vehicle interior. Conventional door inner panels are manufactured using thin cold-rolled steel sheets, and various measures have been taken to ensure strength and rigidity.

[0003] Composite materials that use reinforcing fibers such as carbon fiber and glass fiber as reinforcements have high tensile strength and tensile modulus, and a low coefficient of linear expansion, resulting in excellent dimensional stability. They also have excellent heat resistance, chemical resistance, fatigue resistance, abrasion resistance, electromagnetic wave shielding, and X-ray transparency. For these reasons, composite materials are widely used in a variety of fields, including automobiles, sports and leisure, aerospace, and general industrial applications.

[0004] Patent Document 1 describes a method for manufacturing a back door inner panel by integrally molding two types of reinforced plastics, and the reinforced plastics forming both sides of the window frame have relatively high mechanical strength.

[0005] Patent Document 2 describes a back door inner panel in which a reinforcing portion is formed using prepreg and the remaining portion is formed using sheet molding compound. Generally, prepreg is a sheet substrate in which continuous fibers aligned in one direction are impregnated with resin. Since the continuous fibers in prepreg are aligned in one direction, even slight deviation in the prepreg arrangement prevents the desired physical properties from being achieved. Therefore, when molding using prepreg, extremely strict prepreg arrangement and prevention of positional deviation are required.

[0006] Patent Document 3 describes a method for producing a molded article by placing a plate-shaped material in a mold and then injecting an injection material into the mold.

[0007] Patent Document 4 describes a method for producing an injection-molded product containing multiple sheets at lower cost. In Patent Document 4, multiple resin-impregnated reinforcing member sheets with holes are arranged, a movable mold is moved to clamp the mold, and resin is injected to fill the spaces between the resin-impregnated reinforcing member sheets. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2015 / 091448 [Patent Document 2] Japanese Patent Application Publication No. 2019-10910 [Patent Document 3] International Publication No. 2020 / 196076 [Patent Document 4] Japanese Patent Publication No. 2020-179549 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when forming a rear door inner panel by continuous injection molding two types of reinforced plastics, it is difficult to control the fiber orientation within the two side frames that extend vertically. Furthermore, because the injection molding material is a kneaded material, the fiber length becomes short, and the injection molding material alone does not provide the strength required for the two side frames.

[0010] Furthermore, prepregs generally contain continuous fibers, and even slight misalignment in the prepreg positioning during molding (even a misalignment of a few millimeters) makes it difficult to achieve the desired physical properties. Therefore, measures such as modifying the molding die to prevent misalignment of the prepreg are required.

[0011] In Patent Document 3, no consideration is given to the use as a door inner panel.

[0012] Patent Document 4 does not consider its use as a door inner panel. Furthermore, the method of Patent Document 4 uses a reinforcing member resin-impregnated sheet made of a plain-woven cloth made of glass fibers with a wire diameter of approximately 17 μm, impregnated with polypropylene resin. When using a material in which the reinforcing fibers are continuous and oriented in a specific direction, such as a plain-woven cloth, even slight misalignment (even a few millimeters) in the arrangement when the injection material is introduced and press-molded makes it difficult to achieve the desired physical properties. Therefore, measures such as modifying the molding die to prevent the reinforcing member resin-impregnated sheet from shifting are required. In particular, when attempting to impregnate resin between multiple reinforcing members, the process becomes too complicated. An object of the present invention is to provide a method for manufacturing a door inner panel and a door inner panel that can ensure mechanical strength in the side frame that extends in the vertical direction, which is a relatively narrow area that becomes a window frame. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides the following means. <1> A method for manufacturing a door inner panel including a side frame extending in a vertical direction, the door inner panel being integrally molded from a composite material X including reinforcing fibers dispersed in an in-plane direction and an injection molding material Y, comprising: A method for manufacturing a door inner panel, comprising the following steps (1) to (4): (1) placing the composite material X on a molding fixture of a molding die; (2) a step of lowering the movable molding die of the molding die and bringing the movable molding die into contact with the composite material X; (3) injecting the injection molding material Y into the mold; (4) A step of pressing the composite material X and the injection molding material Y in a mold to integrally mold the door inner panel. <2> the molding die has an area in which the composite material X is placed at a position corresponding to the side frame, a first gate for injecting the injection molding material Y into the mold in an area where the composite material X is placed; <1> A method for manufacturing the door inner panel according to claim 1. <3> The composite material X is brought into contact with the cavity wall surface of the mold to form a skin layer including an X portion formed from the composite material X. <1> or <2> A method for manufacturing the door inner panel according to claim 1. <4> The skin layer including the X portion is formed on the surface of the door inner panel that is disposed on the vehicle inner side. <3> A method for manufacturing the door inner panel according to claim 1. <5> The skin layer including the X portion is formed on the surface of the door inner panel that is disposed on the vehicle outer side. <3> A method for manufacturing the door inner panel according to claim 1. <6> The mold is a first gate for injecting the injection molding material Y into the mold in a region where the composite material X is to be placed; a second gate for injecting the injection molding material Y into the mold in an area other than the area where the composite material X is placed; and the number n1 of the first gates and the number n2 of the second gates satisfy n1>n2≧0; <1> ~ <5> 10. A method for manufacturing a door inner panel according to claim 9. <7> The mold is a first gate for injecting the injection molding material Y into a region of the mold where the composite material X is to be placed; a second gate for injecting the injection molding material Y into an area other than the area in which the composite material X is placed within the mold; and the discharge amount V1 of the injection molding material Y from the first gate and the discharge amount V2 of the injection molding material Y from the second gate satisfy V1>V2≧0; The manufacturing method of the door inner panel according to any one of <1> to <5>. <8> Contact the injection molding material Y with the cavity wall surface of the molding die to form a skin layer including a Y part formed by molding the injection molding material Y. The manufacturing method of the door inner panel according to <1> or <2>. <9> The molding die A first gate for injecting the injection molding material Y into the region where the composite material X in the molding die is arranged, A second gate for injecting the injection molding material Y into a region other than the region where the composite material X in the molding die is arranged, has The number n1 of the first gates and the number n2 of the second gates satisfy 0 < n1 < n2. The manufacturing method of the door inner panel according to any one of <1>, <2> or <8>. <10> The molding die A first gate for injecting the injection molding material Y into the region where the composite material X in the molding die is arranged, A second gate for injecting the injection molding material Y into a region other than the region where the composite material X in the molding die is arranged, has The discharge amount V1 of the injection molding material Y from the first gate and the discharge amount V2 of the injection molding material Y from the second gate satisfy 0 < V1 < V2. The manufacturing method of the door inner panel according to any one of <1>, <2>, <8> or <9>. <11> The surface of the side frame on the vehicle inner side becomes the interior design part when it becomes a vehicle, In the step (4), transfer the shape of the texture provided on the inner wall surface of the cavity of the molding die to the interior design part. The manufacturing method of the door inner panel according to any one of <1> to <10>. ​​At least one of the movable forming die and the fixed forming die has a hole forming member for forming a hole in the door inner panel, In a step prior to the step (1), a hole Xa is formed in the composite material X, In the step (1), the composite material X is placed in a mold so that the hole Xa corresponds to the hole-forming member. <1> ~ <11> 10. A method for manufacturing a door inner panel according to claim 9. <13> Holes Xa are provided in the composite material X at locations corresponding to the upper part of the side frame and at locations corresponding to the lower part of the side frame. <12> A method for manufacturing the door inner panel according to claim 1. <14> In the step (3), the injection molding material Y is kneaded before injection, and a clearance is provided between the movable mold and the fixed mold, and the injection molding material Y is filled. <1> ~ <13> 10. A method for manufacturing a door inner panel according to claim 9. <15> The composite material X includes reinforcing fibers A having a weight average fiber length LwA of 1 mm or more and 100 mm or less, The injection molding material Y contains reinforcing fibers B having a weight average fiber length LwB smaller than LwA, The mechanical strength of the reinforcing portion formed from the composite material X is higher than the mechanical strength of the main body portion formed from the injection molding material Y. <1> A method for manufacturing the door inner panel according to claim 1. <16> The door inner panel is a back door inner panel. <1> ~ <15> 10. A method for manufacturing a door inner panel according to claim 9. <17> Prior to the step (2), a metal fitting for connection with the hinge is disposed in a region to be connected with the hinge, and the metal fitting is insert-molded together with the composite material X and the injection molding material Y. <16> A method for manufacturing the door inner panel according to claim 1. <18> Prior to the step (2), a metal fitting for connecting to the trunk lock is disposed in an area where the trunk lock is to be mounted, and the metal fitting is insert-molded together with the composite material X and the injection molding material Y. <16> A method for manufacturing the door inner panel according to claim 1. <19> The door inner panel is The lower half and a pair of side frames extending upward from the upper left end and upper right end of the lower half portion; a beam portion connecting upper ends of the pair of side frames to each other, The central portion and the lower half portion of the beam portion are made of injection molding material Y. <16> ~ <18> 10. A method for manufacturing a door inner panel according to claim 9. <20> the metal fitting is a metal fastener having a bolt insertion portion, The door inner panel has a hole at a position corresponding to the bolt insertion portion. <17> or <18> A method for manufacturing the door inner panel according to claim 1. <21> a hole is provided at a position corresponding to the bolt insertion portion of the Y portion molded with the injection molding material Y; <20> A method for manufacturing the door inner panel according to claim 1. <22> The metal fitting is in contact with the Y portion where the injection molding material Y is molded. <20> or <21> A method for manufacturing the door inner panel according to claim 1. <23> The metal fitting is not in contact with the X portion where the composite material X is molded. <20> or <21> A method for manufacturing the door inner panel according to claim 1. <24> The door inner panel has a rib within 30 mm of the metal fitting. <20> ~ <23> 10. A method for manufacturing a door inner panel according to claim 9. <25> The door inner panel has a thickness deviation portion within 30 mm from the metal fitting. <20> or <21> A method for manufacturing the door inner panel according to claim 1. <26> In step (4), a hole is provided at a position corresponding to the bolt insertion portion. <20> ~ <25> 10. A method for manufacturing a back door inner panel according to any one of the above. <27> At least one of the movable forming die and the fixed forming die has a hole forming member for forming a hole at a position corresponding to the bolt insertion portion, In a step prior to the step (1), a hole Xa is formed in the composite material X, In the step (1), the composite material X is placed in a mold so that the hole Xa corresponds to the hole-forming member, In the step (4), a hole is formed at a position corresponding to the bolt insertion portion by the hole forming member. <20> ~ <22> or <25> 10. A method for manufacturing a door inner panel according to claim 9. <28> The lower half and a pair of side frames extending upward from the upper left end and upper right end of the lower half portion; a beam portion connecting the upper ends of the pair of side frames; A door inner panel having The pair of side frames includes an X portion molded from a composite material X containing reinforcing fibers dispersed in an in-plane direction, and a Y portion molded from an injection molding material Y, The central portion and the lower half portion of the beam portion include the Y portion molded with the injection molding material Y. Door inner panel. [Effects of the Invention]

[0014] The door inner panel of the present invention uses composite material X in which reinforcing fibers are dispersed in the in-plane direction, so even if composite material X flows slightly during molding, its basic mechanical properties do not change significantly. Therefore, when manufacturing a door inner panel for an automobile having a window opening, the target mechanical strength can be easily obtained by using composite material X even in both side frames extending in the vertical direction of the vehicle on either side of the window opening, which are relatively narrow regions that will become the window frame. Furthermore, shape conformability is improved compared to composite materials using continuous fibers such as plain weave cloth. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a door inner panel 1 according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the door inner panel 1 taken along the line II-II in FIG. 1. [Figure 3] 3 is a cross-sectional view showing a state in which a bracket 101 is attached to the inner side of the vehicle of the beam portion 2 of FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the door inner panel 1 taken along the line IV-IV in FIG. 1. [Figure 5] 5 is a cross-sectional view showing a state in which a bracket 111 is attached to the vehicle inner side of the side frame 3L in FIG. 4. FIG. [Figure 6] 6 is a cross-sectional view of the door inner panel 1 taken along the line VI-VI in FIG. [Figure 7] 7 is a cross-sectional view showing a state in which a bracket 121 is attached to the inside of the vehicle of the lower half 4 of FIG. 6. FIG. [Figure 8] FIG. 1 is a diagram showing a state in which a composite material X is placed on a fixed molding die 201. [Figure 9] 10 is a diagram showing a state in which the movable forming die 301 is brought close to the fixed forming die 201 and brought into contact with the composite material X. FIG. [Figure 10] 2 is a diagram showing a state in which injection molding material Y is injected into the mold through a gate 203 provided in the fixed mold 201. FIG. [Figure 11]FIG. 1 is a diagram showing a state in which composite material X and injection molding material Y are pressed in a mold to be integrally molded. [Figure 12] 10 is a diagram showing a state in which a composite material X is placed above a fixed molding die 201 with a hole forming member 205 inserted into the hole Xa. [Figure 13] FIG. 2 is a plan view of the fixed molding die 201. [Figure 14] FIG. 10 is a plan view of a fixed molding die 201A according to the second embodiment. [Figure 15] FIG. 10 is a horizontal cross-sectional view showing fixed forming mold 201B and movable forming mold 301B that are provided so as to be able to open and close in the horizontal direction. [Figure 16] FIG. 2 is a perspective view showing a box-shaped molded body 400. [Figure 17] FIG. 1 is a plan view showing a composite material in a pattern-cut shape. [Figure 18] FIG. 2 is a front view showing a fixed molding die 201C in which a pattern-cut composite material X is fixed by a fixing member 210C. [Figure 19] FIG. 10 is a horizontal cross-sectional view showing a fixed forming die 201C and a movable forming die 301C to which a composite material X is fixed by a fixing member 210C. DETAILED DESCRIPTION OF THE INVENTION

[0016] [First embodiment] The first embodiment of the present invention will be described in detail below. [Door inner panel] 1 is a schematic diagram of a door inner panel 1 according to an embodiment of the present invention. The door inner panel 1 has a beam portion 2, a pair of side frames 3L, 3R, and a lower half portion 4. The pair of side frames 3L, 3R extend upward from the upper left and upper right ends of the lower half portion 4, and the upper ends of the side frames 3L, 3R are connected to each other by the beam portion 2. The portion surrounded by the beam portion 2, the side frames 3L, 3R, and the lower half portion 4 is a window opening 5. The side frames 3L, 3R extend in the vertical direction of the vehicle, sandwiching the window opening 5 therebetween, and form a so-called window frame.

[0017] The door inner panel 1 of the present invention is preferably a back door inner panel. The back door preferably includes a door inner panel 1 located on the inside of the vehicle, i.e., the front side of the vehicle, and a door outer panel located on the outside of the vehicle, i.e., the rear side of the vehicle. The door outer panel may be a panel made of resin. Moreover, an interior panel may be provided on the vehicle interior side of the door inner panel 1. Hereinafter, the "back door inner panel" may also be simply referred to as the "door inner panel."

[0018] The back door on which the door inner panel 1 of the present invention is mounted may be, for example, a back door that opens and closes vertically or horizontally and is provided at the rear end of the vehicle body. The back door is connected to the vehicle body by a hinge so that it can be opened and closed in the vertical or horizontal direction. When the back door opens and closes in the vertical direction, a hinge is provided at the upper end of the back door. The hinge allows the back door to swing vertically or horizontally around the hinge as a fulcrum to open and close the opening in the vehicle body.

[0019] The door inner panel 1 is provided with a hinge fastening portion 6 for connection with a hinge. When the back door opens and closes in the vertical direction, the hinge fastening portion 6 is preferably present at the upper end of the door inner panel 1.

[0020] When the tailgate opens and closes in the vertical direction, one end of a rod-shaped spring-integrated damper is attached to both the left and right sides of the rear end of the vehicle body, and the other end of the damper is connected to both widthwise edges of the tailgate's inner door panel by damper stays, so that the tailgate opens and closes while being biased by the damper. The damper stays are fasteners for the damper, and the damper prevents the tailgate from closing unintentionally. It is preferable to provide a damper fastening portion 7 at the portion of the door inner panel 1 where the damper stay is attached. It is preferable to fasten and fix the damper stay to the damper fastening portion 7, thereby fixing the damper to the door inner panel 1.

[0021] Various functional parts may be attached to the door inner panel 1, and mounting spaces for electrical parts may be provided. For example, mounting portions for functional parts such as door locks, window regulators, inside handles, door armrests, door trim pads, weather strips, and door check link receivers, as well as for electrical parts such as speakers, switches for electric remote control mirrors, and switches for power windows, may be provided in appropriate positions on the door inner panel 1. A trunk lock 8 may be mounted on the door inner panel 1. In FIG.

[0022] The door inner panel 1 of the present invention has a resin panel made of composite material X and injection molding material Y. Composite material X is disposed at least in the side frames 3L and 3R, and injection molding material Y is molded integrally with composite material X to form the door inner panel. The central portion and the lower half portion 4 of the beam portion 2 are preferably made of an injection molding material Y. The composite material X forms a reinforcing portion of the door inner panel 1. The mechanical strength of the reinforcing portion is higher than the mechanical strength of the main body portion formed by the injection molding material Y. In addition to the resin panel, the door inner panel 1 may also have metal fittings 91 to 93 (see FIGS. 2 to 7) that are integrally molded as described later.

[0023] The composite material X includes reinforcing fibers and a matrix resin. In the composite material X, the reinforcing fibers are dispersed in the in-plane direction within the matrix resin. By using a composite material X in which the reinforcing fibers are dispersed in the in-plane direction, even if the composite material X is displaced from the intended position during molding, the physical properties of the molded resin panel are not significantly affected. This simplifies the manufacturing process and stabilizes the quality of the resulting molded body (door inner panel 1). Hereinafter, the "door inner panel" or the "back door inner panel" may be referred to as the "molded body."

[0024] A metal fitting 91 may be attached to the door inner panel 1 at the position of the hinge fastening portion 6. Also, a metal fitting 92 may be attached at the position of the damper fastening portion 7. The above metal fitting may be formed integrally with the resin panel of the back door inner panel 1 by insert molding. Insert molding is a molding method in which resin is poured around a metal fitting inserted into a molding die to integrate the metal fitting and resin. There are no particular limitations on the insert molding method.

[0025] [Cross-sectional shape of resin panel] The cross-sectional shape of the resin panel is not particularly limited. The resin panel preferably has at least one flat surface. The cross-sectional shape may be T-shaped, L-shaped, C-shaped, hat-shaped, or any three-dimensional shape including these, and may further have an uneven shape (for example, a rib, a boss, etc.).

[0026] The resin panel preferably has a cross-sectional shape that includes a hat-shaped portion.

[0027] Fig. 2 is a cross-sectional view of the door inner panel 1 of Fig. 1 taken along the line II-II. As shown in Fig. 2, the beam portion 2 has an inner wall 21 disposed on the inner side of the vehicle, outer walls 22T and 22B disposed on the outer side of the vehicle, a connecting wall 23T connecting the inner wall 21 and the outer wall 22T, and a connecting wall 23B connecting the inner wall 21 and the outer wall 22B. The connecting wall 23T is connected to an upper end of the inner wall 21, and the outer wall 22T is connected to an upper end of the connecting wall 23T. The connecting wall 23B is connected to a lower end of the inner wall 21, and the outer wall 22B is connected to a lower end of the connecting wall 23B.

[0028] 2, a metal fitting 91 is provided integrally with the connecting wall 23T. The metal fitting 91 is preferably provided integrally with the connecting wall 23T by insert molding. A bolt insertion hole 91a (bolt insertion portion) is provided in the metal fitting 91. Furthermore, it is preferable that a hole 23a is provided in the connecting wall 23T at a position corresponding to the bolt insertion hole 91a.

[0029] The beam portion 2 may further have ribs 24 that connect the connecting walls 23T and 23B to each other. The rib 24 is preferably provided at a distance within 30 mm from the fitting 91. On the other hand, the rib 24 may be provided at a position more than 30 mm away from the fitting 91. The rib 24 may be provided using the composite material X, or the rib 44 may be provided using the injection molding material Y.

[0030] FIG. 3 is a cross-sectional view showing a state in which a bracket 101 is attached to the vehicle inner side of the beam portion 2 in FIG. 2. As shown in FIG. 3, a bolt 102 is inserted through the fitting 91 and the bracket 101, and the nut 103 is fastened to the bolt 102, whereby the bracket 101 is attached to the beam portion 2. By attaching a hinge to the bracket 101, a hinge can be attached to the door inner panel 1. As shown in FIG. 3, it is preferable to insert the bolt 102 into the bracket 101 and the fitting 91 from the vehicle inner side and fasten it to the nut 103 on the vehicle outer side. By using the fitting 91 for the portion to be connected to the hinge, the strength can be ensured.

[0031] The bracket 101 preferably makes surface contact only with the fitting 91 and does not contact the resin panel. Only the metals of the fitting 91 and the bracket 101 make surface contact, thereby improving the stability of fastening. The area S1 of the contact surface of the bracket 101 with the fitting 91 is preferably smaller than the area S2 of the portion where the fitting 91 is exposed from the resin panel. By S1 < S2, even when the fitting 91 embedded in the resin panel is brought into surface contact with the bracket 101, the resin panel is not sandwiched between the fitting 91 and the bracket 101, and the fastening strength can be stabilized. Note that the portion of the resin panel that contacts the fitting 91 is preferably formed only from the molding material Y. [[ID=​​Fig. 4 is a cross-sectional view of the door inner panel 1 of Fig. 1 taken along the line IV-IV. As shown in Fig. 4, the side frame 3L has an inner wall 31 disposed on the inner side of the vehicle, outer walls 32R and 32L disposed on the outer side of the vehicle, a connecting wall 33R connecting the inner wall 31 and the outer wall 32R, and a connecting wall 33L connecting the inner wall 31 and the outer wall 32L. The connecting wall 33R is connected to the right end of the inner wall 31, and the outer wall 32R is connected to the right end of the connecting wall 33R. The connecting wall 33L is connected to the left end of the inner wall 31, and the outer wall 32L is connected to the left end of the connecting wall 33L. As shown in Fig. 4, a metal fitting 92 is provided integrally with the connecting wall 33R. The metal fitting 92 is preferably provided integrally with the connecting wall 33R by insert molding. A bolt insertion hole 92a (bolt insertion portion) is provided in the metal fitting 92. Furthermore, it is preferable that a hole 33a is provided in the connecting wall 33R at a position corresponding to the bolt insertion hole 92a.

[0033] The side frame 3L may further have a rib 34 connecting the connecting walls 33R, 33L to each other. The rib 34 is preferably provided within 30 mm from the metal fitting 92. However, the rib 34 may also be provided at a position more than 30 mm away from the metal fitting 92. The rib 34 may be provided using a composite material X, or may be provided using an injection molding material Y.

[0034] Fig. 5 is a cross-sectional view showing a state in which a bracket 111 is attached to the vehicle inner side of the side frame 3L of Fig. 4. As shown in Fig. 5, a bolt 112 is inserted through the metal fitting 92 and the bracket 111, and a nut 113 is fastened to the bolt 112, thereby attaching the bracket 111 to the side frame 3L. By attaching a damper stay to the bracket 111, a damper can be attached to the door inner panel 1. Note that, as shown in Fig. 5, it is preferable to insert the bolt 112 into the bracket 111 and the metal fitting 92 from the vehicle inner side and fasten it to the nut 113 on the vehicle outer side. By using metal fittings 92 at the part that connects to the damper, strength can be ensured.

[0035] The bracket 111 preferably makes surface contact only with the metal fitting 92 and does not contact the resin panel. By having only the metals of the metal fitting 92 and the bracket 111 in surface contact, the stability of fastening is improved. It is preferable that the area S1 of the contact surface of the bracket 111 with the metal fitting 92 is smaller than the area S2 of the portion where the metal fitting 92 is exposed from the resin panel. By having S1 < S2, even when the metal fitting 92 embedded in the resin panel is brought into surface contact with the bracket 111, the resin panel is not sandwiched between the metal fitting 92 and the bracket 111, and the fastening strength can be stabilized. Note that the portion of the resin panel that contacts the metal fitting 92 is preferably formed only from the molding material Y. Since the side frame 3R has a shape that is substantially bilaterally symmetric with the side frame 3L, illustration of the cross-sectional shape is omitted.

[0036] FIG. 6 is a cross-sectional view taken along the VI-VI arrow of the door inner panel 1 of FIG. 1. As shown in FIG. 6, the lower half portion 4 has an inner wall 41 disposed on the vehicle inner side, outer walls 42T and 42B disposed on the vehicle outer side, connecting walls 43T that connect the inner wall 41 and the outer wall 42T, and connecting walls 43B that connect the inner wall 41 and the outer wall 42B. The connecting wall 43T is connected to the upper end portion of the inner wall 41, and the outer wall 42T is connected to the upper end portion of the connecting wall 43T. Further, the connecting wall 43B is connected to the lower end portion of the inner wall 41, and the outer wall 42B is connected to the lower end portion of the connecting wall 43B.

[0037] As shown in FIG. 6, a metal fitting 93 is provided integrally with the connecting wall 43B. The metal fitting 93 is preferably provided integrally with the connecting wall 43B by insert molding. The metal fitting 93 is provided with a bolt insertion hole 93a (bolt insertion portion). Further, it is preferable to provide a hole 43a at a position corresponding to the bolt insertion hole 93a in the connecting wall 43B.

[0038] The lower half part 4 may further have ribs 44 that connect the connecting walls 43T and 43B. The ribs 44 are preferably provided at a distance within 30 mm from the fitting 93. On the other hand, the ribs 44 may be provided at a position more than 30 mm away from the fitting 93. The ribs 44 may be provided using the composite material X, or the ribs 44 may be provided using the injection molding material Y.

[0039] FIG. 7 is a cross-sectional view showing a state where a bracket 121 is attached to the inner side of the vehicle of the lower half part 4 of FIG. 6. As shown in FIG. 7, a bolt 122 is inserted through the fitting 93 and the bracket 121, and the nut 123 is fastened to the bolt 122, whereby the bracket 121 is attached to the lower half part 4. By attaching the trunk lock 8 to the bracket 121, the trunk lock 8 can be attached to the door inner panel 1. As shown in FIG. 7, it is preferable to insert the bolt 122 into the bracket 121 and the fitting 93 from the inner side of the vehicle and fasten it to the nut 123 on the outer side of the vehicle. By using the fitting 93 at the portion connected to the trunk lock 8, the strength can be ensured.

[0040] The bracket 121 preferably makes surface contact only with the fitting 93 and does not contact the resin panel. Only the metals of the fitting 93 and the bracket 121 make surface contact, thereby improving the stability of fastening. The area S1 of the contact surface of the bracket 121 with the fitting 93 is preferably smaller than the area S2 of the portion where the fitting 93 is exposed from the resin panel. By S1 < S2, even if the fitting 93 embedded in the resin panel is brought into surface contact with the bracket 121, the resin panel is not sandwiched between the fitting 93 and the bracket 121, and the fastening strength can be stabilized. Note that the portion of the resin panel that contacts the fitting 93 is preferably formed only from the molding material Y.

[0041] The resin panel of the door inner panel 1 may include a thickness variation portion. That is, the resin panel may include a thickness variation structure. For example, the thickness of the resin panel in the portions corresponding to the hinge fastening portion 6, the damper fastening portion 7, and the trunk lock 8 may be made thicker than the thickness of the resin panel in other portions of the back door inner panel 1. When using metal fittings 91-93, it is preferable that the uneven thickness portion of the door inner panel is located within 30 mm of the metal fittings 91-93. In other words, the periphery of the metal fittings 91-93 may have an uneven thickness structure. Furthermore, when the metal fittings 91-93 are covered by the Y portion, it is preferable to provide an uneven thickness structure in which the portion within 30 mm of the metal fittings 91-93 is thicker than other portions due to the thickness of the X portion and the thickness of the Y portion. It is more preferable that the uneven thickness portion of the back door inner panel is located within 20 mm of the metal fittings 91-93. On the other hand, thickness variations may be present at positions more than 30 mm away from the metal fittings 91 to 93.

[0042] When a resin panel has a thickness deviation structure (a portion with an uneven thickness), it is preferable that the Y portion contributes to the thickness deviation structure. This is because it is preferable that the composite material X used to create the X portion is plate-shaped, and therefore it is preferable to create the Y portion that is not plate-shaped using the injection molding material Y. Using the injection molding material Y makes it easy to manufacture a back door inner panel with a thickness deviation structure.

[0043] For example, when manufacturing a door inner panel having a thickness variation structure in which the thickness gradually decreases from 2 mm to 3 mm, a 1 mm thick composite material X is placed in a mold, and injection molding material Y is poured into the remaining 1 mm to 2 mm region to form the thickness variation structure.

[0044] When a sheet molding compound (sometimes called SMC) containing reinforcing fibers is used as the composite material X and the metal fitting 91 is covered at the same time as the composite material X is molded, the X portion can contribute to the uneven thickness structure.

[0045] Composite material X and injection molding material Y will be described in more detail below.

[0046] [Reinforced fiber] In this specification, the reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, aramid fiber, and glass fiber, and more preferably carbon fiber or glass fiber. More specifically, the reinforcing fibers contained in the composite material X are preferably carbon fibers or glass fibers. The reinforcing fibers contained in the injection molding material Y are preferably carbon fibers or glass fibers.

[0047] [Carbon fiber] 1. Carbon fiber in general Commonly known carbon fibers for use in the present invention include polyacrylonitrile (PAN)-based carbon fibers, petroleum / coal pitch-based carbon fibers, rayon-based carbon fibers, cellulose-based carbon fibers, lignin-based carbon fibers, and phenol-based carbon fibers. Any of these carbon fibers can be suitably used in the present invention. Among these, polyacrylonitrile (PAN)-based carbon fibers are preferred in the present invention because of their excellent tensile strength. Examples of PAN-based carbon fibers that can be used include the carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) manufactured by Teijin Limited.

[0048] 2. Carbon fiber sizing agent The carbon fiber used in the present invention may have a sizing agent attached to its surface. When using carbon fiber with a sizing agent attached, the type of sizing agent can be appropriately selected depending on the type of carbon fiber and the type of resin used in composite material X or injection molding material Y, and is not particularly limited.

[0049] [Glass fiber] The case where the reinforcing fiber used in the present invention is glass fiber will be described. 1. Glass fiber in general The glass fiber used in the present invention may be any glass fiber generally referred to as glass fiber. The glass composition is not particularly limited to A-glass, C-glass, E-glass, etc., as specified in JIS R3140:2006, and may contain components such as TiO2, SO3, and P2O5. For example, Nitto Boseki's E-glass RS240QR-483 (count: 2400 g / 1000 m) glass fiber can be used as the glass fiber.

[0050] 2. Glass fiber sizing agent The glass fiber used in the present invention may have a sizing agent attached to its surface. When using glass fiber with a sizing agent attached, the type of sizing agent can be appropriately selected depending on the type of glass fiber and the type of resin, and is not particularly limited. Glass fiber that has been pre-treated with a conventionally known coupling agent such as an organosilane compound, an organotitanium compound, an organoborane compound, or an epoxy compound can be preferably used.

[0051] [Dispersion in the in-plane direction] The reinforcing fibers contained in the composite material X of the present invention are dispersed in the in-plane direction. Dispersion of the reinforcing fibers in the in-plane direction means that the reinforcing fibers are dispersed so that their fiber axes are oriented in the in-plane direction. It is preferable that the angle between the fiber axes of the reinforcing fibers and the in-plane direction is 45° or less.

[0052] 1. In-plane direction The composite material X is preferably a plate-shaped material. The in-plane direction is any direction parallel to a plane perpendicular to the thickness direction of the composite material X.

[0053] 2. Random distribution in two dimensions The reinforcing fibers are preferably dispersed two-dimensionally and randomly in the in-plane direction of the composite material X. When the composite material X is press-molded without flowing, the shape of the reinforcing fibers is largely maintained before and after molding, and therefore, it is preferable that the reinforcing fibers contained in the X portion of the door inner panel (molded body) molded from the molding material are also dispersed two-dimensionally and randomly in the in-plane direction. Here, "dispersed two-dimensionally at random" refers to a state in which the reinforcing fibers are not oriented in a specific direction in the in-plane direction of composite material X or part X, but are oriented randomly, and are arranged in the sheet plane without showing any specific directionality overall. Composite material X (or part X of a molded product) obtained using discontinuous fibers dispersed two-dimensionally at random does not have anisotropy in the plane and is substantially isotropic.

[0054] The degree of two-dimensional random orientation is evaluated by determining the ratio of the tensile modulus in two mutually perpendicular directions. The reinforcing fibers can be evaluated as being two-dimensionally randomly dispersed if the ratio (Eδ) obtained by dividing the larger of the tensile modulus values ​​measured in any direction of the composite material (or X portion of the molded article) by the smaller of the two measured tensile modulus values ​​in the direction perpendicular to that direction is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less. Because the X portion of the door inner panel 1 is a curved surface, a method for evaluating the two-dimensional random dispersion in the in-plane direction is to heat the door inner panel 1 above its softening temperature, return it to a flat plate shape, remove only the X portion, and then solidify it. Then, a test piece is cut from the X portion, which has been returned to a flat plate shape, and the tensile modulus is measured to confirm the state of random dispersion in the two-dimensional direction.

[0055] [Fiber length of reinforcing fibers contained in X section] The composite material X preferably contains reinforcing fibers A having a weight average fiber length LwA. Since the weight-average fiber length of composite material X does not change before and after molding, the weight-average fiber length LwA of the reinforcing fibers contained in composite material X can be determined by examining the weight-average fiber length of the reinforcing fibers contained in part X. The weight average fiber length of reinforcing fiber A contained in part X is preferably 1 mm or more, more preferably 3 mm or more. The weight average fiber length of reinforcing fiber A contained in part X is more preferably 3 mm or more and 100 mm or less. The weight average fiber length LwA of reinforcing fiber A is more preferably 3 mm or more and 80 mm or less, and even more preferably 5 mm or more and 60 mm or less. If LwA is 100 mm or less, when the composite material X is manufactured by press molding, the fluidity of the material is less likely to decrease, and it is easy to form the fiber reinforced resin member into a desired shape. Also, when LwA is 1 mm or more, the mechanical strength of the obtained fiber reinforced resin member is less likely to decrease, which is preferable. The weight average fiber length and number average fiber length of the reinforcing fiber are obtained by the following formulas (1) and (2).

[0056] [Fiber length of reinforcing fiber contained in part Y] The injection molding material Y contains reinforcing fiber B with a weight average fiber length LwB, and it is preferable that LwB < LwA. Thereby, the mechanical strength of the reinforcing part formed by the composite material X can be made higher than the mechanical strength of the main body part formed by the injection molding material Y. The composite material X forms both side frames extending in the vertical direction of the window opening. This region is generally narrower than other parts and requires higher strength than other parts (for example, parts made only of the injection molding material Y).

[0057] In the "step (3) injecting the injection molding material Y into the mold" described later, the injection molding material Y is the one immediately before injection. If there is a kneading step before injection, the one after kneading is called the injection molding material Y. Since the weight average fiber length does not change after kneading, if the weight average fiber length of the reinforcing fiber contained in part Y is examined, the weight average fiber length LwB of the reinforcing fiber contained in the injection molding material Y can be known. The weight average fiber length LwB of the reinforcing fiber B is preferably less than 3 mm. The weight average fiber length LwB is more preferably 0.01 mm or more and less than 3 mm. The lower limit is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more. When the weight average fiber length LwB is 0.01 mm or more, mechanical strength is ensured. On the other hand, the upper limit of the weight average fiber length LwB is preferably less than 3 mm, more preferably less than 2 mm, and even more preferably less than 1 mm. When the weight average fiber length LwB is 1.0 mm or less, it is easy to produce the injection molding material Y by kneading. When injection is performed, a kneading process is performed, and the weight average fiber length of the reinforcing fibers that have undergone a sufficient kneading process is generally less than 1 mm. The weight average fiber length and number average fiber length of the reinforcing fibers can be calculated by the formulas (1) and (2) described below.

[0058] [Number average fiber length Ln and weight average fiber length Lw] Generally, the fiber length of each reinforcing fiber is L i Then, the number average fiber length Ln and the weight average fiber length Lw can be calculated by the following formulas (1) and (2): The number average fiber length Ln and the weight average fiber length Lw are expressed in mm.

number

[0059] Here, "I" indicates the number of reinforcing fibers measured. When the fiber length is constant, the number average fiber length and the weight average fiber length are the same value. Reinforcing fibers can be extracted from door inner panels, for example, by heating them at 500°C for about 1 hour and removing the resin in a furnace. The number average fiber length Ln and the weight average fiber length Lw are calculated by, for example, calculating the fiber lengths L1 to L2 of 100 fibers (I=100) randomly extracted from a door inner panel. 100 can be measured to the nearest 1 mm using a caliper or the like and calculated based on equations (1) and (2). If the material contains short fibers that cannot be measured with a caliper, after removing the resin, the resulting reinforcing fibers are placed in water containing a surfactant, and thoroughly stirred with ultrasonic vibrations. The stirred dispersion of reinforcing fibers is randomly sampled with a measuring spoon to obtain an evaluation sample, and the length of 3,000 reinforcing fibers (I=3,000) is measured using the Luzex AP image analyzer manufactured by Nireco Corporation. The measured fiber length values ​​L1 to L 3000 Using these formulas, the number average fiber length Ln and the weight average fiber length Lw can be calculated in the same manner as in the above formulas (1) and (2).

[0060] [Volume ratio of reinforcing fibers in parts X and Y] The reinforcing fiber volume fraction (Vf) of each of the X portion and the Y portion can be calculated by the following formula (3). There is no particular limitation on the reinforcing fiber volume fraction, but the reinforcing fiber volume fraction (Vf) is preferably 10 to 60 Vol%, more preferably 20 to 50 Vol%, and even more preferably 25 to 45 Vol%. Reinforcing fiber volume fraction (Vf) = 100 × reinforcing fiber volume / (reinforcing fiber volume + resin volume) Equation (3) In the present invention, it is preferable from the viewpoint of the manufacturing process that the reinforcing fiber volume fraction Vfb of the Y portion and the carbon fiber volume fraction Vfa of the X portion satisfy the relationship Vfa ≧ Vfb. For example, when crushed scraps recovered from the manufacturing process or product are used as the injection molding material Y, or when crushed scraps are used to produce the Y portion by adding a thermoplastic resin to the injection molding material Y, Vfa > Vfb is often satisfied. In other words, if a manufacturing method that satisfies Vfa ≧ Vfb is adopted, the scraps remaining after cutting out the X portion can be used efficiently and the material can be easily recycled. Vfa is preferably 20 to 45 Vol %, more preferably 25 to 40 Vol %. Vfb is preferably 1 to 40 Vol %, more preferably 5 to 30 Vol %, and even more preferably 10 to 25 Vol %.

[0061] [Analysis of reinforcing fiber volume fraction (Vf)] Although there is no limitation on the analysis of the reinforcing fiber volume fraction, it is recommended to measure it as follows. A sample is cut from part X or part Y, and the resin is burned off in a furnace at 500°C for 1 hour. The mass of the sample before and after treatment is weighed to calculate the mass of the reinforcing fiber and resin. Next, the volume ratio of the reinforcing fiber to the resin is calculated using the specific gravity of each component. Vf = 100 × reinforcing fiber volume / (reinforcing fiber volume + resin volume)

[0062] [resin] The matrix resin contained in the composite material X and the resin contained in the injection molding material Y may be either thermosetting or thermoplastic.

[0063] 1. Thermoplastic resin 1.1 Overview When the resin used is a thermoplastic resin, the type is not particularly limited, and a resin having a desired softening point or melting point can be appropriately selected and used. As the thermoplastic resin, one having a softening point in the range of 180°C to 350°C is usually used, but is not limited thereto.

[0064] Examples of thermoplastic resins include polyolefin resins, polystyrene resins, polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyethernitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyether ketone resins, thermoplastic urethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins.

[0065] The thermoplastic resin used in the resin panel of the door inner panel 1 of the present invention may be one type or two or more types. Examples of a mode in which two or more types of thermoplastic resins are used in combination include, but are not limited to, a mode in which thermoplastic resins having different softening points or melting points are used in combination, or a mode in which thermoplastic resins having different average molecular weights are used in combination. When a thermoplastic resin is used, it is more preferable to use a polyolefin resin, and even more preferable to use a polypropylene resin.

[0066] 1.2 Composite material X and injection molding material Y resin The resin contained in injection molding material Y is preferably a thermoplastic resin. When the resin contained in X portion is a thermoplastic resin, it is more preferable that the resins contained in composite material X and injection molding material Y are the same type of thermoplastic resin.

[0067] 2. Thermosetting resin The resin contained in the composite material X may be a thermosetting resin. In this case, the composite material X may be a sheet molding compound using reinforcing fibers. Due to its high moldability, the sheet molding compound can be easily molded into even complex shapes. The sheet molding compound has higher fluidity and shaping properties than continuous fibers, Ribs and bosses can be easily created.

[0068] [Other agents] The resin used in the composite material X or the injection molding material Y may contain additives such as various fibrous or non-fibrous fillers such as organic or inorganic fibers, flame retardants, UV-resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, surfactants, etc., within the scope of the present invention.

[0069] [Preferable resin and fiber combinations] [fiber] Preferably, the reinforcing fibers A contained in the composite material X are glass fibers and / or carbon fibers, and the reinforcing fibers B contained in the injection molding material Y are glass fibers. Carbon fiber can be used in some parts of the reinforcing fiber A contained in the composite material X, and glass fiber can be used in other parts. The part where carbon fiber is used is preferably the periphery of the hole Xa described below, and is preferably used to reinforce fastening.

[0070] [resin] The resin contained in composite material X may be a thermoplastic resin or a thermosetting resin, and the resin contained in injection molding material Y may be a thermoplastic resin or a thermosetting resin. While injection molding material Y contains a thermoplastic resin, composite material X may contain a thermosetting sheet molding compound.

[0071] It is preferable that the volume Va of the composite material X used and the volume Vb of the injection molding material Y used satisfy the relationship Vb≧Va. Va:Vb is preferably 10:90 to 50:50, and more preferably 20:80 to 40:60. When Va:Vb is 10:90 to 50:50, the side frames 3L, 3R extending in the vertical direction of the window opening 5 can be formed using the composite material X, and the door inner panel 1 can be formed using the injection molding material Y with high fluidity for the remaining portion.

[0072] [X and Y parts] After molding, composite material X preferably forms part X. Similarly, after molding, injection molding material Y preferably forms part Y.

[0073] [Side frame] 1. Aspect 1 The door inner panel 1 of the present invention has a skin layer that faces the inside of the vehicle and a skin layer that faces the outside of the vehicle. Here, the skin layer is a layer that is formed when molding materials (composite material X, injection molding material Y) come into contact with the cavity wall surface of a molding die, cools, and solidifies. In both side frames 3L, 3R, it is preferable that at least a part of one of the skin layers has an X portion. In composite material X, the reinforcing fibers are dispersed in the in-plane direction, so when composite material X becomes part X, the reinforcing fibers dispersed in the in-plane direction can be observed, creating a beautiful design surface.

[0074] It is more preferable that the skin layer having the X portion is provided on the surface of the door inner panel 1 that faces the vehicle interior. Even more preferably, the surfaces of both side frames 3L, 3R extending in the vertical direction of the window opening 5 that face the vehicle interior are to become the interior design part when the vehicle is completed. It is even more preferable that the pattern of the grain provided on the inner wall surface of the cavity of the movable molding die or fixed molding die is transferred to the interior design part. Of the surfaces of the door inner panel 1 that face the vehicle interior, the surfaces formed by the Y portion other than the surfaces that face the vehicle interior of the side frames 3L, 3R may be covered and hidden by an interior panel.

[0075] The one-side skin layer where the X portion is observed may be the surface on the vehicle outer side of the door inner panel 1. In this case, most of the skin layer on the vehicle inner side of the door inner panel 1 will be the Y portion, so the appearance of the door inner panel 1 when viewed from the vehicle inside can be made to have a unified look.

[0076] [Manufacturing method] Next, we will explain a method for manufacturing the door inner panel 1. In this embodiment, a plate-shaped composite material X is used, and the door inner panel 1 is manufactured by flowing an injection molding material Y in the in-plane direction of the composite material X to extend the surface.

[0077] The manufacturing method for manufacturing the door inner panel 1 by press molding includes the following steps (1) to (4): (1) placing composite material X in a cavity of a fixed molding die; (2) a step of bringing the movable molding die close to the fixed molding die and bringing the movable molding die into contact with the composite material X; (3) injecting an injection molding material Y into the mold; (4) A process of pressing the composite material X and the injection molding material Y in a mold to integrally mold the door inner panel 1.

[0078] When the resin contained in the composite material X and the injection molding material Y is a thermoplastic resin, it is preferable to use cold press molding. Although the following description focuses on cold press molding, the composite material X and the injection molding material Y may also be integrally molded by hot press molding.

[0079] The manufacturing method for manufacturing the door inner panel 1 by cold press molding includes the following steps (0) to (4): (0) heating composite material X to a first predetermined temperature; (1) placing composite material X in a cavity of a fixed molding die; (2) a step of bringing the movable molding die close to the fixed molding die and bringing the movable molding die into contact with the composite material X; (3) injecting an injection molding material Y into the mold; (4) A process of pressing the composite material X and the injection molding material Y in a mold to integrally mold the door inner panel 1.

[0080] (0) Heating composite material X to a first predetermined temperature It is preferable that the composite material X is preheated to a first predetermined temperature. When the thermoplastic resin contained in the composite material X is crystalline, the first predetermined temperature is a temperature above the melting point and below the decomposition temperature of the thermoplastic resin. When the thermoplastic resin contained in the composite material X is amorphous, the first predetermined temperature is a temperature above the glass transition temperature and below the decomposition temperature of the thermoplastic resin.

[0081] (1) A process of placing composite material X in the cavity of a fixed molding die. 8, a composite material X is placed on a fixed molding die 201. When the door inner panel is a back door inner panel, at least one composite material X is placed at each position corresponding to both side frames 3L and 3R. The step of placing the composite material X on the fixed molding die can be carried out using a conventionally known method. The composite material X may be pre-shaped and placed in the fixed molding die so that it fits the molding die.

[0082] In the case of cold press molding, the temperature of the molding stationary mold 201 is adjusted to a second predetermined temperature. If the thermoplastic resin contained in the composite material X is crystalline, the second predetermined temperature is a temperature below the melting point of the thermoplastic resin. If the thermoplastic resin contained in the composite material X is amorphous, the second predetermined temperature is a temperature below the glass transition temperature of the thermoplastic resin. In this way, by adjusting the temperatures of the composite material X and the molding die, cold pressing can be carried out suitably.

[0083] (2) A step of bringing the movable molding die close to the fixed molding die and bringing the movable molding die into contact with composite material X. Next, as shown in FIG. 9, the movable forming die 301 is brought close to the fixed forming die 201 and brought into contact with the composite material X.

[0084] (3) A step of injecting injection molding material Y into the mold. 10, injection molding material Y is injected into the mold through gate 203 provided in fixed molding die 201. The injection molding material Y may be injected immediately before or immediately after movable molding die 301 begins to apply pressure to a portion of composite material X. In order to prevent the composite material X from shifting position within the mold, it is preferable to inject the injection molding material Y immediately after it comes into contact with at least a portion of the composite material X and pressure begins to be applied. The method for injecting the injection molding material Y into the mold is not particularly limited, and any conventionally known method can be used. At this time, the composite material X is pressed against the movable molding die 301 by the pressure of the injection molding material Y.

[0085] The injection molding material Y is kneaded, and it is preferable to fill the injection material by providing a clearance between the fixed molding die 201 and the movable molding die 301. By pressing the injection molding material Y after filling it into the mold, it is possible to prevent the composite material X from shifting in position. When the injection molding material Y is poured into the mold, it is preferably heated to a temperature above the melting point and below the decomposition temperature of the thermoplastic resin if the thermoplastic resin contained in the injection molding material Y is crystalline, or above the glass transition temperature and below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous.

[0086] To fill the injection molding material Y with a clearance between the fixed molding die 201 and the movable molding die 301, it is sufficient to stop the approach of the movable molding die 301 once before the molding die is completely closed. The position at which the movable molding die is stopped is preferably after the movable molding die 301 has come into contact with the composite material X. By restricting the movement of the composite material X by having the composite material X come into contact with the movable molding die 301, it is possible to prevent the composite material X from shifting in position during pressing.

[0087] (4) A process of pressing the composite material X and the injection molding material Y in a mold to integrally mold the door inner panel 1. Next, the composite material X and the injection molding material Y are pressed into a mold to form an integral mold, as shown in Figure 11. The molding pressure is not particularly limited, but is preferably less than 20 MPa relative to the projected area of ​​the cavity of the mold, and more preferably 10 MPa or less. At this time, composite material X is cooled by contacting the cavity wall surface of movable molding die 301, and the X portion where composite material X has solidified forms part of the skin layer. If a textured pattern is provided on the cavity wall surface of fixed molding die 201 or movable molding die 301, the textured pattern is transferred to the skin layer of door inner panel 1. After molding, composite material X forms X portion, injection molding material Y forms Y portion, and X portion and Y portion constitute door inner panel 1.

[0088] Thereafter, the integrally molded door inner panel 1 is removed from the mold. In this way, the X portion and the Y portion are integrally formed, and therefore the joining strength between the X portion and the Y portion is excellent. Furthermore, since the easily flowing injection molding material Y is injected and pressed while the plate-shaped composite material X is placed in the mold, it is possible to manufacture door inner panels with complex shapes having ribs and bosses. Various steps may be added between the above steps (0) to (4). Alternatively, the above steps may be carried out under vacuum by vacuum press molding.

[0089] Although the method for manufacturing the door inner panel 1 by cold press molding has been described above, the door inner panel 1 may also be manufactured by hot press molding. In this case, step (0) is unnecessary. For example, when a thermosetting sheet molding compound (SMC) is used as the composite material X, the mold may be set to the curing temperature of the SMC.

[0090] [Insert molding] Composite material X is added to the mold and metal fittings 91 to 93 are placed in advance, and then injection molding material Y is injected into the mold and pressed, thereby making it possible to manufacture a door inner panel with integrated metal fittings in a single molding process, resulting in excellent productivity. When the metal fittings 91 to 93 are insert molded, it is preferable to place the metal fittings 91 to 93 in the fixed mold before step (2) and fix them to the fixed mold 201 so that they do not move during the pressing process. It is preferable to clamp the metal fittings 91 to 93 to the fixed mold 201 in advance and design it so that the molded body (door inner panel) can be removed from the mold using a slide core as soon as molding is completed.

[0091] [Placement of hardware] It is preferable that at least one of the metal fittings 91 to 93 is covered by the portion Y. For example, the metal fittings 91 to 93 are placed in a mold in advance, and an injection molding material Y is injected into the mold, so that the injection molding material Y covers the metal fittings 91 to 93, and after molding, the metal fittings 91 to 93 are covered by the portion Y. At this time, the portion X is molded integrally with the metal fittings 91 to 93 via the portion Y.

[0092] Furthermore, it is preferable that the X portion does not contact at least one of the metal fittings 91-93. For example, when insert molding, the composite material X and the metal fittings 91-93 are placed in a mold in advance without contacting each other, and then the injection molding material Y is injected into the mold. By injecting the injection molding material Y, the metal fittings 91-93 are covered by the Y portion. This manufacturing method leads to a reduction in manufacturing steps. Furthermore, by designing the metal fittings 91-93 to be covered by the Y portion and not in contact with the X portion, welds generated by contact between the composite material X and the injection molding material Y are not present around the metal fastener. In other words, it is more preferable that the metal fittings 91-93 are covered by the Y portion, and that no welds generated by the Y portion are present on the contact surfaces with the metal fittings 91-93. Note that if the X portion is not in contact with the metal fittings 91-93, it is preferable that it is in contact with the Y portion.

[0093] As explained in Figures 2, 4, and 6, when bolt insertion holes 91a to 93a are provided in metal fittings 91 to 93, it is preferable to provide holes 23a, 33a, and 43a at positions corresponding to the bolt insertion holes 91a to 93a of the resin panel into which metal fittings 91 to 93 are insert-molded. When holes 23a, 33a, and 43a are formed in the X portion, holes Xa may be formed in advance, prior to step (1), at positions corresponding to holes 23a, 33a, and 43a in the composite material X. Hole-forming members are provided in the molding die at positions corresponding to holes Xa in the composite material X, and after the hole-forming members are inserted into holes Xa in the composite material X, molding of the composite material X is completed, whereby holes 23a, 33a, and 43a can be formed in the X portion.

[0094] In order to prevent the composite material X from being displaced during molding, a hole forming member for forming holes Xa in the composite material X is provided in at least one of the fixed molding die and the movable molding die, In a step prior to the step (1), a hole Xa is formed in the composite material X; In step (1), it is preferable to place the composite material X in the mold with the hole-forming member inserted into the hole Xa. For example, in step (1), as shown in FIG. 12, a hole forming member 205 is provided in the molding and fixing die 201, and the composite material X is placed on the upper part of the molding and fixing die 201 with the hole forming member 205 inserted into the hole Xa. The hole forming member 205 is provided by arranging pins in the molding and fixing die 201 and may sometimes be called a core pin. Note that the projected area of the hole Xa is larger than the projected area of the hole forming member 205. Thereafter, by performing steps (2) to (4), the door inner panel 1 can be molded while preventing the displacement of the composite material X during molding. In addition, as the hole Xa provided in the composite material X, holes other than the holes 23a, 33a, and 43a corresponding to the bolt insertion holes 91a to 93a may be provided.

[0095] If the hole Xa is sufficiently large, the injection molding material Y passes through the hole Xa. Therefore, when providing a skin layer including the Y part on both sides of the door inner panel 1, it is preferable that the hole Xa is sufficiently large.

[0096] The mold for providing the hole forming member 205 may be either a male or female mold. However, when using the composite material X in a preheated and softened state, in order to facilitate the supply of the composite material X, it is preferably provided in the mold on the side where the composite material X is placed. In some cases, it may be provided in both male and female molds so that the tip surfaces of the hole forming members face each other and contact during mold clamping.

[0097] When placing the composite material X with a thickness t on the molding and fixing die 201, it is preferable that the average distance Lf between the inner wall surface of the hole Xa of the composite material X and the hole forming member 205 satisfies 0 < Lf < 10t. This means that when the thickness t of the composite material X is large, the flow distance of the composite material X can be increased. For example, when the thickness of the composite material X is 2.5 mm, the average distance Lf may be set to 0 < Lf < 25 mm. The distance between the inner wall surface of the hole Xa of the composite material X and the hole forming member is, for example, the distance L from the inner wall surface of the hole Xa to the hole forming member 205 as shown by 805 in (12). The average distance Lf is the average of L even when the shapes of the hole forming member 205 and the hole Xa are irregular or there is a bias in the placement location.

[0098] It is more preferable to provide the holes Xa at positions disposed at the upper and lower parts of the side frames 3L and 3R of the composite material X. It is preferable to provide the holes Xa at two or more positions per composite material X. By providing the holes Xa at two or more positions in the composite material X, it is possible to suitably suppress displacement of the composite material X. For example, hole Xa may be provided at a position corresponding to holes 23a and 33a. Here, hole 23a is provided at a location located at the upper part of side frames 3L and 3R, and hole 33a is provided at a location located at the lower part. Alternatively, hole Xa may be provided at a different position not corresponding to holes 23a and 33a.

[0099] On the other hand, holes may be provided in the Y portion to serve as the holes 23a, 33a, and 43a provided in the door inner panel 1. In the case of insert molding, in which injection molding material Y is injected into a mold, if the mold is designed in advance to have holes 23a, 33a, and 43a, then holes 23a, 33a, and 43a can be created in the Y portion once injection molding material Y has been poured and molding is complete. Also, holes corresponding to holes 23a, 33a, and 43a may be provided in both the X and Y portions, or holes may be provided in both the X and Y portions at positions not corresponding to holes 23a, 33a, and 43a. The holes 23a, 33a, 43a can be easily formed at the same time as integral molding of both the X portion and the Y portion. Forming the holes 23a, 33a, 43a by integral molding simplifies the manufacturing process. After the press molding in (4) is completed, the holes 23a, 33a, and 43a may be formed by secondary processing.

[0100] [Gate Location] In order to manufacture a door inner panel 1 in which portion X is observed in at least a part of the skin layer, it is preferable to provide a gate for injecting injection molding material Y in the area where composite material X is placed. In FIGS. 8 to 11, an example has been described in which gate 203 is provided at the position in fixed mold 201 where composite material X is placed, but a gate for injecting injection molding material Y may also be provided at the position in movable mold 301 where composite material X is placed. In this case, composite material X is pressed against fixed mold 201 by the pressure of molding material Y. Because the gap between composite material X and the cavity wall surface of the movable mold is sealed, it is possible to prevent injection molding material Y from entering between composite material X and the cavity wall surface of the movable mold.

[0101] Fig. 13 is a plan view of the forming fixed mold 201. As shown in Fig. 13, the upper surface of the forming fixed mold 201 is provided with a region 2A corresponding to the shape of the beam portion 2, a region 3LA corresponding to the shape of the side frame 3L, a region 3RA corresponding to the shape of the side frame 3R, and a region 4A corresponding to the shape of the lower half portion 4. Note that the region XA corresponding to the composite material X, the region 6A corresponding to the hinge fastening portion 6, the region 7A corresponding to the damper fastening portion 7, and the region 8A corresponding to the region where the trunk lock 8 is to be disposed are indicated by dashed lines. There is no particular limitation on the location of the gate for injecting the injection molding material Y. For example, the gate for injecting the injection molding material Y may be provided in an area (2A, 4A) other than the area XA where the composite material X is placed.

[0102] [Number of gates] In order to manufacture a door inner panel 1 in which an X portion is observed in at least a part of the skin layer, it is preferable that the number of gates satisfies n1>n2≧0, where: n1 is the number of first gates provided in the region (XA) where the composite material X is placed in the plan view of the cavity of the molding die; n2 is the number of second gates provided in the region other than the region where composite material X is placed in the plan view of the cavity of the forming mold.

[0103] 13, one gate 202 is provided in region 2A, eight gates 203 are provided in region XA, and three gates 204 are provided in region 4A. Gate 203 is a first gate provided in region XA, and gates 202 and 204 are second gates provided in regions other than region XA. In this case, n1=8 and n2=4, satisfying n1>n2≧0. In this way, when n1>n2≧0 is satisfied, the injection molding material Y injected from gate 203 presses the composite material X against the inner wall of the cavity of the movable molding die, and the injection molding material Y also spreads to areas other than area XA, so that the injection molding material Y injected from gates 202 and 204 can be prevented from getting between the composite material X and the cavity wall surface of the movable molding die. 13 illustrates a case where gates 202 to 204 for injecting injection molding material Y are provided in fixed mold 201, but gates for injecting injection molding material Y may also be provided in movable mold 301. Even in this case, by satisfying n1>n2≧0, the gap between composite material X and the cavity wall surface of fixed mold 201 is blocked, thereby preventing injection molding material Y from entering between composite material X and the cavity wall surface of fixed mold 201.

[0104] [Discharge volume from gate] In order to manufacture both side frames in which the X portion is observed in at least a portion of one of the skin layers, it is preferable that the discharge amount of the injection molding material Y from the gate for injecting the injection molding material Y satisfies V1>V2≧0, where: V1 is the amount of injection molding material Y discharged from the first gate (203) provided in the region (XA) where composite material X is placed in the plan view of the cavity of the mold; V2 is the amount of injection molding material Y discharged from the second gates (202, 204) provided in areas (2A, 4A) other than the area where composite material X is placed in a plan view of the cavity of the mold.

[0105] For example, in the example shown in FIG. 13, one gate 202 is provided in region 2A, eight gates 203 are provided in region XA, and three gates are provided in region 4A. At this time, if the total discharge amount of the injection molding material Y discharged from the gate 203 is V1 and the total discharge amount of the injection molding material Y discharged from the gates 202 and 204 is V2, it is preferable to satisfy V1 > V2 ≧ 0. The injection molding material Y injected from the gate 203 presses the composite material X against the inner wall of the cavity of the movable mold, and the injection molding material Y further spreads to regions other than the region XA. Since the discharge amount V1 of the injection molding material Y injected from the gate 203 is larger than the discharge amount V2 of the injection molding material Y injected from the gates 202 and 204, the injection molding material Y injected from the gates 202 and 204 cannot reach the composite material X, and it is possible to suppress the injection molding material Y from entering between the cavity wall surface of the movable mold and the composite material X.

[0106] [Second Embodiment] Next, a second embodiment of the present invention will be described. Regarding the same configuration as that of the first embodiment, the description will be omitted. In the second embodiment, the skin layers on both sides of the side frames 3L and 3R may include a Y portion at least partially. By forming the skin layer on the vehicle inner side and the skin layer on the vehicle outer side of the door inner panel 1 with the Y portion, it is possible to give a sense of unity to the appearance of the door inner panel 1 as viewed from the vehicle inner side and the appearance as viewed from the vehicle outer side.

[0107] FIG. 14 is a plan view of the molding fixed mold 201A according to the second embodiment. Regarding the same configuration as that of FIG. 13, the same reference numerals are given and the description will be omitted.

[0108] [Number of Gates] In the side frames 3L and 3R, in order to make the skin layers on both sides have a Y portion at least partially, the injection molding material Y may be made to enter between the composite material X and the cavity wall surface of the molding die. In this case, it is preferable that the number of gates for injecting the injection molding material Y satisfies 0 < n1 < n2. Here: n1 is the number of the first gates provided in the region (XA) where the composite material X is arranged in a plan view of the cavity of the mold; n2 is the number of the second gates provided in the regions other than the region where the composite material X is arranged in a plan view of the cavity of the mold.

[0109] For example, in the example shown in FIG. 14, three gates 202 are provided in the region 2A, six gates 203 are provided in the region XA, and five gates 204 are provided in the region 4A. The gate 203 is the first gate provided in the region XA, and the gates 202 and 204 are the second gates provided in the regions other than the region XA. In this case, n1 = 6, n2 = 8, and 0 < n1 < n2 is satisfied. When 0 < n1 < n2 is satisfied, since the injection molding material Y injected from the gates 202 and 204 spreads to the region XA where the composite material X is arranged, it is possible to promote the injection molding material Y to enter between the composite material X and the cavity wall surface of the movable mold.

[0110] [Discharge amount from the gate] In order to make the skin layers on both sides of the side frames 3L and 3R have the Y part at least partially, it is preferable that the discharge amount from the gate for injecting the injection molding material Y satisfies 0 < V1 < V2. Here: V1 is the discharge amount of the injection molding material Y from the first gate provided in the region (XA) where the composite material X is arranged in a plan view of the cavity of the mold; V2 is the discharge amount of the injection molding material Y from the second gate provided in the regions other than the region (XA) where the composite material X is arranged in a plan view of the cavity of the mold.

[0111] For example, in the example shown in FIG. 14, three gates 202 are provided in region 2A, six gates 203 are provided in region XA, and five gates are provided in region 4A. At this time, if the total discharge amount of the injection molding material Y discharged from gate 203 is V1, and the total discharge amount of the injection molding material Y discharged from gates 202 and 204 is V2, it is preferable to satisfy 0 < V1 < V2. When 0 < V1 < V2 is satisfied, since the injection molding material Y ejected from gates 202 and 204 spreads to region XA where the composite material X is arranged, it is possible to promote the injection molding material Y from entering between the composite material X and the cavity wall surface of the molding movable mold.

[0112] [Opening and closing direction of the molding die] 1. Vertical direction In the present invention, there is no particular limitation on the opening and closing direction of the molding die. However, the molding fixed die may be the molding lower die, the molding movable die may be the molding upper die, and the molding upper die may move up and down toward the molding lower die to open and close the molding die. 2. Horizontal direction On the other hand, the molding movable die may be moved horizontally toward the molding fixed die to open and close to manufacture a molded body.

[0113] When manufacturing a molded body by opening and closing by moving the molding movable die horizontally, it is preferable that there are at least two or more fixing members for fixing the composite material X to the molding fixed die. FIG. 15 is a horizontal cross-sectional view showing a molding fixed die 201B and a molding movable die 301B provided so as to be openable and closable in the horizontal direction. In FIG. 15, a plurality of fixing members 210 for fixing the composite material X to the molding fixed die 201B are provided. It is preferable that the horizontal positions of the plurality of fixing members 210 are different. By providing the plurality of fixing members 210 at different horizontal positions of the molding fixed die 201B, it is possible to prevent the displacement of the composite material X with respect to the molding fixed die 201B. The fixing members 210 may be provided at different positions in the height direction. Three or more fixing members 210 may be provided at different positions in the height direction and the horizontal direction. In addition, holes 310 into which the fixing members 210 are inserted may be provided at positions facing the fixing members 210 of the molding movable die 301B. 3. Fixed and movable types Depending on the mold, the fixed mold may move. If the fixed mold moves, the mold that moves a relatively small distance is called the fixed mold, and the mold that moves a relatively large distance is called the movable mold.

[0114] [Pattern Cut] The composite material X may have a shape obtained by pattern cutting. Pattern cutting refers to a composite material that is pre-cut into a desired shape to match the shape of the molded body. It does not have to be a simple shape such as a square or rectangle. For example, when manufacturing a box-shaped molded body 400 as shown in FIG. 16, the composite material X may have a shape with margins added to the portions that make up the developed view of the box, as shown in FIG. 17. In FIG. 17, four portions 402 that will become the side surfaces are provided around a portion 401 that will become the bottom surface of the rectangular box, and a margin 403 is provided at the portion where the adjacent portions 402 that will become the side surfaces are joined during molding. Although a margin 403 is provided only on one of the two adjacent portions 402 that will become the side surfaces in FIG. 17, a margin 403 may be provided on both sides.

[0115] When the resin contained in the composite material X is a thermoplastic resin and the molding method is cold pressing, it is particularly preferable that the composite material X has a shape that has been pattern-cut and cut out. In the case of cold pressing, the resin begins to solidify the moment the composite material X comes into contact with the molding die, so the fluidity during molding is lower than that of thermosetting resins. Therefore, if the composite material X is cut into the desired shape in advance, it is easier to create a molded product of the desired shape. The pattern-cut shape is preferably a shape developed by computer using inverse molding analysis from the three-dimensional shape of the press-molded product to be manufactured.

[0116] [Pattern cutting and fixing parts] When the composite material X has a shape obtained by pattern cutting and the molded body is produced by opening and closing the movable molding die by moving it horizontally toward the fixed molding die, it is preferable to fix the composite material X by a plurality of fixing members provided on the fixed molding die. Fig. 18 is a front view showing the molding and fixing mold 201C in a state in which the pattern-cut composite material X is fixed by fixing members 210C. As shown in Fig. 18, it is preferable to fix the composite material X to the molding and fixing mold 201C by fixing members 210C at multiple locations spaced apart in the horizontal direction in a portion 401 that will become the bottom surface of a rectangular box, for example.

[0117] FIG. 19 is a horizontal cross-sectional view showing the molding stationary mold 201C and the molding movable mold 301C to which the composite material X is fixed by the fixing member 210C. When the molding mold opens and closes horizontally (left and right in FIG. 19), the composite material X needs to be arranged so that the plate surface faces up and down (perpendicular to the paper surface of FIG. 19). In this case, when a pattern-cut composite material X is used, there is a higher possibility that the composite material will sag in an unintended direction compared to a composite material with a simple shape such as a square or rectangle. Therefore, by appropriately fixing the composite material X to the molding stationary mold 201C using the fixing member 210C, it is possible to effectively prevent the composite material X from sagging in an unintended direction. In Figure 18, the composite material X may be pre-shaped so that the side surface portion 402 and margin 403, which are above the bottom surface portion 401 fixed to the molding fixed mold 201C by the fixing member 210C, do not fall toward the molding movable mold 301C (see Figure 19) but instead fall toward the molding fixed mold 201C.

[0118] [Injection from a fixed mold and design] Injection from the fixed mold and design will be explained below. The above-mentioned step (3) of injecting the injection molding material Y into the mold includes a step of injecting the injection molding material Y between the fixed mold and the movable mold, and it is preferable to inject the injection molding material Y from the fixed mold. Compared to injecting the injection molding material Y from the movable mold, injecting from the fixed mold is preferable because the equipment is not too complicated.

[0119] 1. Formation of design surface When injection molding material Y is injected from a fixed mold, it is preferable that the design surface be formed by the movable mold. This is because the surface of the molded body formed by the fixed mold leaves a mark from the injection gate, while the surface formed by the movable mold does not. In this case, the design of the molded body can be improved by, for example, making the following improvements to composite material X or the movable mold.

[0120] 2. Composite materials and design surfaces When injection is performed from a fixed mold, it is preferable to fill the injection molding material between the movable mold and composite material X. By filling the injection molding material between the movable mold and composite material X, the fibers contained in the composite material can be hidden. By filling the injection molding material between the movable mold and composite material X, a skin layer is formed. The thickness of the skin layer is preferably 50 μm or more and 300 μm or less, and more preferably 70 μm or more and 200 μm or less.

[0121] 2.1 Flow holes When the design surface is formed by the movable molding die and injection molding material Y is filled between the movable molding die and composite material X, it is preferable to provide one or more flow holes X1 in composite material X through which injection molding material Y passes, and to inject injection molding material Y injected from gate 203 of fixed molding die 201B into the space between composite material X and movable molding die 301B by flowing through said flow hole X1, as shown in Fig. 15 . Injection molding material Y injected from fixed molding die 201B passes through flow hole X1, allowing injection molding material Y to enter between composite material X and movable molding die 301B. In this case, it is preferable to provide gate 203 in the region of fixed molding die 201B where composite material X is placed.

[0122] 2.2 Placement of resin sheet When the design surface is formed by the movable molding mold, it is preferable to place a resin sheet between the composite material X placed in the fixed molding mold and the movable molding mold. If the resin sheet does not contain fibers, it is preferable because it has good transferability to the mirror surface of the movable molding mold. By providing a resin sheet, it becomes easier to form the design surface on the molded body. The resin sheet may be laminated with the composite material X before being placed in the fixed molding mold, or the composite material X may be placed in the fixed molding mold and then the resin sheet may be laminated on the composite material X.

[0123] 2.3 Grain When the design surface of the molded body is formed by the movable mold, the design surface may have a textured pattern formed by the movable mold. By transferring the surface of the movable mold to create a textured pattern on the molded body, the reinforcing fibers contained in the composite material can be made less noticeable, improving the design. To facilitate the transfer of the textured pattern on the surface of the movable mold to the composite material X, a resin-rich layer may be provided on the surface of the composite material X, or a resin sheet may be placed between the movable mold and the composite material X when the composite material X is placed in the fixed mold.

[0124] This application claims priority based on Japanese Patent Application No. 2022-149322 filed on September 20, 2022 and Japanese Patent Application No. 2022-196925 filed on December 9, 2022. [Explanation of symbols]

[0125] 1: Door inner panel 2:Beam part 3L, 3R: Side frame 4:Lower half 5: Window opening 6: Hinge connection part 7: Damper connection part 8: Trunk lock 91, 92, 93: Metal fittings 201, 201A, 201B, 201C: Molded fixed type 202, 203, 204: Gates 205: Hole forming member 210, 210C: Fixing member 301, 301B, 301C: Movable molding type

Claims

1. A method for manufacturing a door inner panel including a side frame extending in a vertical direction, the door inner panel being integrally molded from a composite material X including a matrix resin containing a thermoplastic resin and reinforcing fibers dispersed in an in-plane direction within the matrix resin, and an injection molding material Y, the method comprising: A method for manufacturing a door inner panel, comprising the following steps (0) to (4): (0) heating the composite material X to a first predetermined temperature; (1) a step of placing the composite material X on a molding fixture of a molding die; (2) a step of vertically or horizontally moving the movable molding die of the molding die toward the fixed molding die to bring the movable molding die into contact with the composite material X; (3) injecting the injection molding material Y into the mold; (4) A step of pressing the composite material X and the injection molding material Y in a mold to integrally mold the door inner panel. If the thermoplastic resin is crystalline, the first predetermined temperature is a temperature above the melting point and below the decomposition temperature of the thermoplastic resin, and if the thermoplastic resin is amorphous, the first predetermined temperature is a temperature above the glass transition temperature and below the decomposition temperature of the thermoplastic resin.

2. the molding die has an area in which the composite material X is placed at a position corresponding to the side frame, a first gate for injecting the injection molding material Y into the mold in an area where the composite material X is placed; The method for manufacturing a door inner panel according to claim 1.

3. The composite material X is brought into contact with the cavity wall surface of the mold to form a skin layer including an X portion formed from the composite material X. A method for manufacturing a door inner panel according to claim 1 or 2.

4. The skin layer including the X portion is formed on the surface of the door inner panel that is disposed on the vehicle inner side. The method for manufacturing a door inner panel according to claim 3.

5. The skin layer including the X portion is formed on the surface of the door inner panel that is disposed on the vehicle outer side. The method for manufacturing a door inner panel according to claim 3.

6. The mold is a first gate for injecting the injection molding material Y into the mold in a region where the composite material X is to be placed; a second gate for injecting the injection molding material Y into the mold in an area other than the area where the composite material X is placed; and the number n1 of the first gates and the number n2 of the second gates satisfy n1>n2≧0; A method for manufacturing a door inner panel according to claim 1 or 2.

7. The mold is a first gate for injecting the injection molding material Y into a region of the mold where the composite material X is to be placed; a second gate for injecting the injection molding material Y into an area other than the area in which the composite material X is placed within the mold; and a discharge amount V1 of the injection molding material Y from the first gate and a discharge amount V2 of the injection molding material Y from the second gate satisfy V1>V2≧0; A method for manufacturing a door inner panel according to claim 1 or 2.

8. The injection molding material Y is brought into contact with the cavity wall surface of the mold to form a skin layer including a Y portion formed by the injection molding material Y. A method for manufacturing a door inner panel according to claim 1 or 2.

9. The mold is a first gate for injecting the injection molding material Y into a region of the mold where the composite material X is to be placed; a second gate for injecting the injection molding material Y into an area other than the area in which the composite material X is placed within the mold; and the number n1 of the first gates and the number n2 of the second gates satisfy 0<n1<n2; A method for manufacturing a door inner panel according to claim 1 or 2.

10. The mold is a first gate for injecting the injection molding material Y into the mold in a region where the composite material X is to be placed; a second gate for injecting the injection molding material Y into the mold in an area other than the area where the composite material X is placed; and a discharge amount V1 of the injection molding material Y from the first gate and a discharge amount V2 of the injection molding material Y from the second gate satisfy the relationship 0<V1<V2; A method for manufacturing a door inner panel according to claim 1 or 2.

11. The surface of the side frame facing the inside of the vehicle becomes an interior design part when the vehicle is assembled, In the step (4), the shape of the grain provided on the inner wall surface of the cavity of the molding die is transferred to the interior design portion. A method for manufacturing a door inner panel according to claim 1 or 2.

12. At least one of the movable forming die and the fixed forming die has a hole forming member for forming a hole in the door inner panel, In a step prior to the step (1), a hole Xa is formed in the composite material X, In the step (1), the composite material X is placed in a mold so that the hole Xa corresponds to the hole-forming member. A method for manufacturing a door inner panel according to claim 1 or 2.

13. 13. The method for manufacturing a door inner panel according to claim 12, wherein holes Xa are formed in the composite material X at locations corresponding to upper portions of the side frames and at locations corresponding to lower portions of the side frames.

14. In the step (3), the injection molding material Y is kneaded before injection, and a clearance is provided between the movable mold and the fixed mold, and the injection molding material Y is filled. A method for manufacturing a door inner panel according to claim 1 or 2.

15. The composite material X includes reinforcing fibers A having a weight average fiber length LwA of 1 mm or more and 100 mm or less, The injection molding material Y includes reinforcing fibers B having a weight average fiber length LwB smaller than LwA, the mechanical strength of the reinforcing portion formed from the composite material X is higher than the mechanical strength of the main body portion formed from the injection molding material Y; The method for manufacturing a door inner panel according to claim 1.

16. The door inner panel is a back door inner panel. A method for manufacturing a door inner panel according to claim 1 or 2.

17. Prior to the step (2), a metal fitting for connection to the hinge is disposed in a region to be connected to the hinge, and the metal fitting is insert-molded together with the composite material X and the injection molding material Y. The method for manufacturing a door inner panel according to claim 16.

18. Prior to the step (2), a metal fitting for connecting to the trunk lock is disposed in an area where the trunk lock is to be mounted, and the metal fitting is insert-molded together with the composite material X and the injection molding material Y. The method for manufacturing a door inner panel according to claim 16.

19. The door inner panel is The lower half and a pair of side frames extending upward from an upper left end and an upper right end of the lower half portion; a beam portion connecting upper ends of the pair of side frames to each other, The central portion and the lower half portion of the beam portion are made from the injection molding material Y. The method for manufacturing a door inner panel according to claim 16.

20. the metal fitting is a metal fastener having a bolt insertion portion, The door inner panel has a hole at a position corresponding to the bolt insertion portion. The method for manufacturing a door inner panel according to claim 17.

21. a hole is provided at a position corresponding to the bolt insertion portion of the Y portion molded with the injection molding material Y; The method for manufacturing a door inner panel according to claim 20.

22. The metal fitting is in contact with the Y portion where the injection molding material Y is molded. The method for manufacturing a door inner panel according to claim 20.

23. The metal fitting is not in contact with the X portion where the composite material X is molded. The method for manufacturing a door inner panel according to claim 20.

24. The door inner panel has a rib within a range of 30 mm from the metal fitting. The method for manufacturing a door inner panel according to claim 20.

25. 21. The method for manufacturing a door inner panel according to claim 20, wherein the door inner panel has a thickness deviation portion within 30 mm from the metal fitting.

26. The method for manufacturing a door inner panel according to claim 20, wherein in the step (4), holes are formed at positions corresponding to the bolt insertion portions.

27. At least one of the movable forming die and the fixed forming die has a hole forming member for forming a hole at a position corresponding to the bolt insertion portion, In a step prior to the step (1), a hole Xa is formed in the composite material X, In the step (1), the composite material X is placed in a mold so that the hole Xa corresponds to the hole-forming member; 21. The method for manufacturing a door inner panel according to claim 20, wherein in the step (4), holes are formed by the hole forming member at positions corresponding to the bolt insertion portions.

28. The lower half and a pair of side frames extending upward from an upper left end and an upper right end of the lower half portion; a beam portion connecting the upper ends of the pair of side frames; A door inner panel having The pair of side frames includes an X portion molded from a composite material X including a matrix resin and reinforcing fibers dispersed in an in-plane direction within the matrix resin, and a Y portion molded from an injection molding material Y, The central portion and the lower half portion of the beam portion include the Y portion molded with the injection molding material Y. Door inner panel.

Images