Inner panel and vehicle back door, and inner panel molding method

Abstract

To provide an inner panel of a vehicle back door which suppresses deformation of a reinforcement panel to be inserted when a panel body is molded.SOLUTION: An inner panel (10) includes: a panel body (40) which has a window opening (11) and is made of a resin; and a metal upper reinforcement (50) which is inserted along a pillar part (14) from parts on both right and left sides of an upper frame part (13) in the panel body and is made of metal. The panel body has a surface side resin layer (41) coating the surface side of the upper reinforcement, and a plurality of belt-like resin parts (43) provided on the rear face side of the upper reinforcement. The belt-like resin part extends in such a belt shape as to have a flat cross-sectional shape, is connected to the surface side resin layer at least both ends thereof, and holds the upper reinforcement on the panel body in a state in which the upper reinforcement is partially exposed to the rear face side from the panel body.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an inner panel, a vehicle back door, and a method for molding an inner panel. [Background technology]

[0002] It has been known for some time that a resin inner panel is used in a vehicle back door. In order to ensure rigidity, a metal reinforcing panel made of a steel plate or the like is inserted into the inner panel. Such an inner panel is molded by insert molding (see, for example, Patent Document 1). In insert molding, the reinforcing panel is set in an injection molding die so as to be located within a cavity, and in this state, the die is clamped to form a cavity, and molten resin is injected into the cavity to mold a resin panel body integrally with the reinforcing panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-260724 A Summary of the Invention [Problem to be solved by the invention]

[0004] A vehicle back door is required to be lightweight. For this reason, it is preferable that the reinforcing panel inserted into the inner panel is also relatively thin in order to reduce the weight. However, if a relatively thin reinforcing panel is used, there is a risk that the reinforcing panel will be deformed by the pressure of the resin injected into the cavity of the injection mold when the inner panel is insert molded. If this happens, the reinforcing panel will be exposed on a surface that should not be exposed, or the resin constituting the panel body will become thicker in parts, causing sink marks on the surface of the panel body, thereby reducing the quality of the inner panel.

[0005] An object of the present invention is to suppress deformation of an inserted reinforcing panel during molding of a panel body in an inner panel constituting a vehicle back door. [Means for solving the problem]

[0006] In order to achieve the above object, in the present invention, a metal reinforcing panel that is inserted into a resin panel body is held on its back side by a plurality of strip-shaped resin portions.

[0007] Specifically, the first invention is directed to an inner panel. The inner panel has a window opening formed in an upper half thereof, and is combined with an outer panel to form a vehicle back door. The inner panel of the first invention includes a resin panel body having the window opening, and a metal reinforcing panel inserted along a pillar portion from both left and right portions of an upper frame portion of a window frame portion that forms an outer periphery of the window opening in the panel body.

[0008] The panel body has a top resin layer covering the top surface of the reinforcing panel and a plurality of strip-shaped resin parts provided on the back surface of the reinforcing panel. Each of the strip-shaped resin parts extends in a strip shape having a flat cross-sectional shape, contacts the back surface of the reinforcing panel with one main surface in the thickness direction, and is connected to the top resin layer at at least both ends. The reinforcing panel is held to the panel body by the strip-shaped resin parts, and is partially exposed to the back surface side from the panel body.

[0009] A second invention is an inner panel according to the first invention, in which the strip-shaped resin portion includes a plurality of first strip-shaped resin portions extending along the circumferential direction of the window frame portion and a plurality of second strip-shaped resin portions extending in a direction intersecting the first strip-shaped resin portions and positioned at intervals from each other in the circumferential direction of the window frame portion. The first strip-shaped resin portions and the second strip-shaped resin portions are integrally formed and constitute a net portion that covers the rear surface side of the reinforcing panel in a net-like manner.

[0010] A third invention is the inner panel of the second invention, wherein a portion of the reinforcing panel located at the pillar portion forms a recessed portion extending along the longitudinal direction of the pillar portion and opening to a rear side, and the first belt-shaped resin portion covers a corner portion of the recessed portion.

[0011] A fourth invention is an inner panel described in the third invention, wherein the first band-shaped resin portion contacts a corner portion of the concave portion at a side surface and extends in a width direction corresponding to one surface that is continuous with the corner portion of the concave portion.

[0012] A fifth invention is the inner panel of the second invention, wherein a through hole is formed in the reinforcing panel at a portion corresponding to an intersection of the first and second strip-shaped resin portions, and the net portion and the front-side resin layer are connected via the through hole.

[0013] A sixth aspect of the present invention is the inner panel according to the first aspect of the present invention, further comprising a reinforcing rib provided on a rear surface of the band-shaped resin portion, the reinforcing rib being connected to an outer periphery of the reinforcing panel in the panel body.

[0014] A seventh invention is the inner panel of the first invention, wherein the width of the band-shaped resin portion is 15 mm or less.

[0015] An eighth aspect of the present invention is directed to a vehicle back door, which includes an inner panel according to any one of the first to seventh aspects of the present invention, and an outer panel joined to the inner panel to form a door body.

[0016] The ninth invention is directed to a method for molding an inner panel. The method for molding an inner panel of the ninth invention is a method for molding any one of the inner panels of the first to seventh inventions. The method for molding an inner panel includes a setting step of setting the reinforcing panel in a state in which the back surface of the reinforcing panel is in contact with an injection mold, a mold clamping step of clamping the injection mold to form a cavity for molding the panel main body inside the injection mold at a predetermined boundary portion corresponding to the peripheral portion of the reinforcing panel and around the boundary portion so as to be continuous with the front side of the reinforcing panel, and an injection molding step of injecting and filling the cavity with molten resin, and then solidifying the resin to mold the panel main body integrally with the reinforcing panel.

[0017] The injection molding die used has a boundary between a first space portion of the cavity where the reinforcing panel is not located and a second space portion where the reinforcing panel is located, and has a first gate that opens toward the first space portion and a second gate that opens toward the second space portion. In the injection molding process, the molten resin injected from the first gate into the first space portion flows into the second space portion through the boundary portion, and is then injected into the second space portion from the second gate.

[0018] A tenth invention is a method for molding an inner panel according to the ninth invention, wherein, in the injection molding process, the injection of the molten resin from the first gate is stopped at the time when the molten resin injected from the first gate into the first space portion flows into the second space portion through the boundary portion. Effect of the Invention

[0019] According to the first invention, a metal reinforcing panel inserted into a resin panel main body is held by a plurality of strip-shaped resin parts provided on the back side of the reinforcing panel. Both ends of each strip-shaped resin part are connected to the front-side resin layer. This allows the panel main body to firmly hold the reinforcing panel by the plurality of strip-shaped resin parts. Furthermore, each strip-shaped resin part extends in a strip shape so as to have a flat cross-sectional shape, and contacts the back side of the reinforcing panel with one main surface in the thickness direction. This makes it possible to suppress deformation of the reinforcing panel due to the pressure of the resin injected into the cavity of the injection mold when the inner panel is injection molded, even if a relatively thin reinforcing panel is used.

[0020] According to the first aspect of the present invention, the reinforcing panel is inserted into the panel body in a manner that a part of the reinforcing panel is exposed on the rear surface side of the panel body, thereby making it possible to suppress deformation of the pillar portion by reinforcing the pillar portion with the reinforcing panel while suppressing an increase in weight of the inner panel.

[0021] According to the second invention, the back side of the reinforcing panel is covered by a net portion formed by integrally forming a first strip-shaped resin portion and a second strip-shaped resin portion. When the back door is opened or closed, a load caused by the opening and closing operation is applied to the inner panel, and the reinforcing panel tries to peel off from the front resin layer. At this time, the force that causes the reinforcing panel to peel off is dispersed to the net portion. Therefore, the panel main body can favorably hold the reinforcing panel by the multiple strip-shaped resin portions.

[0022] According to the third invention, a portion of the reinforcing panel located at the pillar portion constitutes a recessed portion, and a corner portion of the recessed portion is covered by the first band-shaped resin portion. This reinforces the corner portion of the reinforcing panel. This improves the rigidity of the pillar portion. Even if the shape accuracy of the corner portion of the reinforcing panel is poor, the corner portion of the reinforcing panel does not interfere with the core mold of the injection molding die when the inner panel is molded. This improves the accuracy of the insert position of the reinforcing panel.

[0023] According to the fourth aspect of the present invention, the first strip-shaped resin portion extends in a width direction corresponding to one surface that is continuous with the corner portion of the recessed portion of the reinforcing panel. This prevents the first strip-shaped resin portion from becoming thick at the corner portion of the reinforcing panel, and allows the first strip-shaped resin portion to be formed to have a flat cross-sectional shape. This makes it possible to suppress deformation caused by the difference in cooling and solidifying time between the first strip-shaped resin portion and the front-side resin layer during molding of the inner panel.

[0024] According to the fifth aspect of the present invention, the net portion and the front-side resin layer are connected via through holes formed at the intersections of the first and second strip-shaped resin portions, whereby the panel body can firmly hold the reinforcing panel by the multiple strip-shaped resin portions.

[0025] According to the sixth aspect of the present invention, the reinforcing rib is provided on the back surface of the strip-shaped resin portion. When the reinforcing rib is provided upright directly on the back surface of the reinforcing panel at a location different from the strip-shaped resin portion, the area of ​​the resin portion forming the reinforcing rib in contact with the reinforcing panel becomes relatively narrow. In contrast, when the reinforcing rib is provided upright on the strip-shaped resin portion, the area of ​​the resin portion forming the reinforcing rib in contact with the reinforcing panel can be secured by the strip-shaped resin portion. Furthermore, since the reinforcing rib is connected to the outer periphery of the reinforcing panel in the panel main body, the reinforcing rib is unlikely to be taken up by the mold when demolding in the manufacture of the inner panel. This is advantageous in increasing the rigidity of the inner panel by providing a relatively high reinforcing rib.

[0026] According to the seventh aspect of the present invention, the strip-shaped resin portion is formed to have a width of 15 mm or less. If the width of the strip-shaped resin portion is 15 mm or less, even if a lightweight and inexpensive pressed steel plate having a thickness of, for example, about 0.5 mm to 0.6 mm is used as the reinforcing panel, the reinforcing panel can be prevented from being deformed by the pressure of the resin when the inner panel is formed. This is advantageous for reducing the weight and cost of the vehicle back door.

[0027] According to an eighth aspect of the present invention, the vehicle back door is provided with an inner panel according to any one of the first to seventh aspects of the present invention. The inner panel can suppress deformation during molding of the panel body even if the reinforcing panel inserted therein is relatively thin. Therefore, by adopting a relatively thin reinforcing panel, the vehicle back door can be made lighter while maintaining the quality of the inner panel.

[0028] According to the ninth invention, in the injection molding process, the molten resin injected from the first gate into the first space where the reinforcing panel is not located flows into the second space where the reinforcing panel is located through a predetermined boundary area corresponding to the peripheral part of the reinforcing panel, and then injection of the molten resin into the second space starts from the second gate. In this way, the molten resin injected from the first gate and flowing into the front side of the reinforcing panel at the boundary area and its periphery presses the reinforcing panel against the core mold before the molten resin is injected from the second gate, and serves as support against the pressure of the resin filled in the space that molds the strip-shaped resin part.

[0029] As a result, when molding the inner panel, the reinforcing panel can be inserted into the panel body at a predetermined position without being supported by a positioning pin in the cavity of the injection molding die. This is advantageous in improving the appearance of the inner panel, since no pressing marks are left on the panel body. In addition, since there is no need for a drive mechanism for moving the positioning pin or a resin sensor for controlling the operation timing of the drive mechanism, the mold structure of the injection molding die does not become complicated.

[0030] According to the tenth aspect of the present invention, in the injection molding process, the injection of molten resin from the first gate is stopped at the timing when the molten resin injected from the first gate into the first space flows into the second space through the boundary portion. This narrows the filling range of the cavity with the molten resin injected from the first gate. If the filling range of the cavity with the molten resin injected from the first gate is wide, the injection pressure of the molten resin from the first gate becomes high. If the injection pressure of the molten resin becomes excessively high, it will cause burrs to occur. On the other hand, by narrowing the filling range of the cavity with the molten resin injected from the first gate, it is possible to prevent the injection pressure of the molten resin from the first gate from becoming excessively high, and suppress the occurrence of burrs. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view of a vehicle back door. [Diagram 2] FIG. 2 is an exploded perspective view of the vehicle back door. [Diagram 3] FIG. 3 is a rear view illustrating a schematic configuration of the inner panel. [Figure 4] FIG. 4 is a rear view illustrating a main part of the inner panel. [Diagram 5] FIG. 5 is a perspective view illustrating a main part of the inner panel surrounded by V in FIG. [Figure 6] 6 is a cross-sectional view of a main part of the inner panel taken along line VI-VI in FIG. [Figure 7] 7 is a cross-sectional view of a main part of the inner panel taken along line VII-VII in FIG. [Figure 8] 8 is a cross-sectional view of a main part of the inner panel taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is a conceptual diagram illustrating an injection molding die together with a cavity and an insert member, as viewed from the cavity die side. [Figure 10] FIG. 10 is a diagram illustrating a state in which molten resin spreads in a cavity of an injection molding die in a molding process of an inner panel. [Figure 11]FIG. 11 is a diagram illustrating a state in which molten resin spreads in a cavity of an injection molding die in a molding process of an inner panel. [Figure 12] FIG. 12 is a diagram illustrating a state in which molten resin spreads in a cavity of an injection molding die in a molding process of an inner panel. [Figure 13] FIG. 13 is a diagram illustrating a state in which molten resin flows in a portion corresponding to line XIII-XIII in FIG. 4 during the molding process of the inner panel. [Figure 14] FIG. 14 is a diagram illustrating a state in which molten resin flows in a portion corresponding to line XIV-XIV in FIG. 4 during the molding process of the inner panel. [Figure 15] FIG. 15 is a diagram illustrating a state in which molten resin flows in a portion corresponding to line XV-XV in FIG. 4 during the molding process of the inner panel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, an exemplary embodiment will be described in detail with reference to the drawings. In the following embodiment, for convenience of explanation, the front side in the vehicle longitudinal direction will be referred to as "front", the rear side will be referred to as "rear", the left side in the vehicle width direction facing the front of the vehicle will be referred to as "left", the right side will be referred to as "right", the upper side in the vehicle height direction will be referred to as "upper", and the lower side will be referred to as "lower". In addition, the back door according to this embodiment will be described assuming a posture with the rear opening of the vehicle closed, unless otherwise specified with respect to the open / closed state.

[0033] <<Embodiment>> The vehicle back door 1 of this embodiment is a flip-up type back door. The upper end of this back door 1 is connected to the upper edge of a rear opening provided in the vehicle body of a hatchback vehicle via a pair of hinges 100. The back door 1 opens and closes the rear opening by rotating in the vertical direction around a rotation axis formed by the pair of hinges 100 and extending in the vehicle width direction.

[0034] -Backdoor configuration- 1 and 2, the back door 1 mainly comprises a door body 5 and a plurality of lamp units 90. A window section 7 is provided in the upper half of the door body 5. The door body 5 is configured by joining an inner panel 10 and an outer panel 60 in a mutually opposing state, and includes a window panel 80 forming the window section 7.

[0035] A damper stay 110 is provided between the door main body 5 and both left and right side portions of the rear opening of the vehicle body. One end of the damper stay 110 is attached to the upper end on both the left and right sides of the rear opening of the vehicle body. The other end of the damper stay 110 is attached to the middle of the edge of the door main body 5 in the left and right direction.

[0036] When the back door 1 is opened, the damper stay 110 biases the door body 5 in the opening direction from a predetermined position. The opening action of the back door 1 is assisted by the biasing force of the damper stay 110. Note that, for the sake of convenience, only the right damper stay 110 is shown in Fig. 2, but a pair of left and right damper stays 110 are connected to the back door 1.

[0037] The lamp units 90 include a high mount stop lamp unit 92 and a rear lamp unit 94. The rear lamp unit 94 includes a tail lamp and a rear blinker. For convenience, only the left rear lamp unit 94 is shown in FIG. 2, but the back door 1 is provided with a pair of left and right rear lamp units 94.

[0038] <Inner panel> The inner panel 10 is a single resin panel, and is combined with the outer panel 60 and the window panel 80 to form the back door 1. As shown in FIG. 3, a window opening 11 is formed in the upper half of the inner panel 10. The window opening 11 is a substantially trapezoidal opening extending in the left-right direction. The inner panel 10 includes a resin panel main body 40 having the window opening 11, and a metal reinforcing panel 50 (indicated by dot hatching in FIGS. 3 to 5) inserted into the panel main body 40.

[0039] The panel body 40 is integrally formed with the reinforcing panel 50 by injection molding. The panel body 40 is made of, for example, a thermoplastic resin containing a fiber reinforcement material. Specifically, the panel body 40 is made of a material such as glass fiber-reinforced polypropylene (PP-GF), carbon fiber-reinforced polypropylene (PP-CF), or cellulose nanofiber-reinforced polypropylene (PP-CNF).

[0040] A pair of upper reinforcement 50A and lower reinforcement 50B are inserted into the reinforcing panel 50. The upper reinforcement 50A and the lower reinforcement 50B are made of an iron plate made of iron (Fe) or stainless steel (SUS), or a galvanized iron plate. The thickness of the upper reinforcement 50A and the lower reinforcement 50B is relatively thin, for example, 0.5 mm to 0.8 mm.

[0041] The upper portion of the window frame portion 12 that forms the outer periphery of the window opening 11 in the panel body 40 constitutes an upper frame portion 13 extending in the left-right direction. The upper frame portion 13 forms the ceiling portion of the door body 5. Furthermore, the left and right portions of the window frame portion 12 each constitute a pillar portion 14 extending in the up-down direction. The pillar portion 14 is formed in a concave shape that opens toward the rear. The portion of the inner panel 10 below the window opening 11 (hereinafter simply referred to as the lower portion) constitutes the lower portion of the door body 5.

[0042] An inner standing wall 16 is provided on the peripheral portion of the window opening 11 in the inner panel 10. The inner standing wall 16 rises rearward toward the outer panel 60. An inner joint piece 18 is provided at the rear end of the inner standing wall 16. The inner joint piece 18 protrudes inwardly into the window opening 11. Furthermore, an outer standing wall 20 is provided on the outer periphery of the inner panel 10. The outer standing wall 20 rises rearward toward the outer panel 60. An outer joint piece 22 is provided at the rear end of the outer standing wall 20. The outer joint piece 22 protrudes toward the outer periphery of the inner panel 10.

[0043] A pair of hinge mounting portions 24 are provided on the outer standing wall 20 of the upper frame portion 13 of the inner panel 10. The outer standing wall 20 on which the pair of hinge mounting portions 24 are provided extends vertically and horizontally, and constitutes a rear end portion at the upper frame portion 13 of the inner panel 10. The pair of hinge mounting portions 24 are formed at positions spaced apart from each other on both sides in the left-right direction. A metal hinge 100 is fixed from the front to each hinge mounting portion 24 by using a first bolt 102 (see FIG. 2).

[0044] A stay attachment portion 25 is provided on the outer wall portion in the vehicle width direction of the lower end of each pillar portion 14. One side end of a damper stay 110 is connected to the stay attachment portion 25 from the outside in the vehicle width direction using a second bolt 112 so as to be able to swing freely (see FIG. 2). A pair of upper reinforcements 50A are provided integrally on both the left and right sides of the inner panel 10 by insert molding.

[0045] Each upper reinforcement 50A is formed roughly in an L shape, and is inserted from both left and right sides of the upper frame portion 13 of the window frame portion 12 of the panel main body 40 along the pillar portion 14. Each upper reinforcement 50A extends from the hinge mounting portion 24 to the stay mounting portion 25, and constitutes the hinge mounting portion 24 and the stay mounting portion 25 together with the panel main body 40.

[0046] An upper service hole 26 is formed in the inner standing wall 16 of the upper frame portion 13 of the inner panel 10. The upper service hole 26 is a work opening used for connecting a harness to the high mounted stop lamp unit 92, maintenance work, and the like. The inner standing wall 16 in which the upper service hole 26 is formed extends in the front-rear and left-right directions, and is formed so that its thickness direction corresponds to the top and bottom.

[0047] The upper service hole 26 is formed in the left-right center of the inner standing wall 16 of the upper frame portion 13. Although not shown, the peripheral portion of the upper service hole 26 in the inner panel 10 is formed so that the underside is recessed upward. A cover member 84 (shown in FIG. 2) is fitted from below into the recess in the peripheral portion of the upper service hole 26. The upper service hole 26 is closed by this cover member 84.

[0048] The upper frame portion 13 of the inner panel 10 is further provided with a plurality of reinforcing ribs 28. The multiple reinforcing ribs 28 are positioned at intervals from one another in the left-right direction. Each reinforcing rib 28 protrudes toward the upper panel 62 and extends linearly in the front-rear direction. The tip of each of these reinforcing ribs 28 is located near the rear surface of the upper panel 62. When the upper panel 62 bends downward, it comes into contact with and is supported by the reinforcing ribs 28. This restricts the upper panel 62 from bending downward.

[0049] Of the multiple reinforcing ribs 28, some (three in this example) reinforcing ribs 28 located in the middle in the left-right direction are formed so as to straddle upper service hole 26. Reinforcing ribs 28 are also formed on both left and right edge portions of upper service hole 26. Each of reinforcing ribs 28 formed on both left and right edge portions of upper service hole 26 corresponds to a recess in the peripheral portion of upper service hole 26, and is positioned so as to overlap cover member 84.

[0050] A latch mounting portion 29 is provided on the lower edge of the lower part of the inner panel 10. A latch (not shown) is attached to the latch mounting portion 29. The latch cooperates with a striker provided on the lower edge of the rear opening of the vehicle body to form a locking mechanism that locks the back door 1 in the closed state. A lower reinforcement 50B is provided integrally with the latch mounting portion 29 by insert molding.

[0051] A parts mounting portion 30 is provided in the upper central portion of the lower part of the inner panel 10. A lamp for illuminating the license plate, a knob mechanism, and the like are attached to the parts mounting portion 30. A lower service hole 31 is formed below the parts mounting portion 30 of the inner panel 10. The lower service hole 31 is an opening used for latch installation work, maintenance work, and the like.

[0052] A recess that is recessed toward the front and protrudes toward the rear is formed in a portion of the inner panel 10 including the component mounting portion 30. The lower service hole 31 is formed in an inner portion of the recess. The opening of the recess is closed from the front side by a cover trim 86. In this inner panel 10, a band-shaped holding structure is employed that holds the upper reinforcement 50A in a manner that partially exposes it on the back side in order to suppress deformation of the upper reinforcement 50A during molding of the panel body 40.

[0053] <Outer panel> 2, the outer panel 60 is divided into two parts, an upper panel 62 and a lower panel 64.

[0054] The upper panel 62 and the lower panel 64 are each a resin panel. The upper panel 62 and the lower panel 64 are formed by injection molding. The material used for the upper panel 62 and the lower panel 64 may be synthetic resin such as talc-containing polypropylene (PP-T) or a mixture of ethylene propylene diene methylene rubber (EPDM).

[0055] The upper panel 62 is provided to face the upper frame portion 13 of the inner panel 10. The upper panel 62 forms the ceiling portion of the door body 5 and constitutes a spoiler portion 66 protruding rearward. A lamp unit attachment portion 67 is provided at the rear end portion of the spoiler portion 66. A high mount stop lamp unit 92 is attached to the lamp unit attachment portion 67. A lower panel portion of the upper panel 62 that constitutes the lower portion of the spoiler portion 66 is folded back diagonally downward and rearward at the front side to constitute an upper joint piece 69.

[0056] An outer edge portion of the upper panel 62 is joined to the inner panel 10 using an adhesive. Specifically, a front edge portion of the upper panel 62 is adhered to the outer joint piece 22 of the inner panel 10. An upper joint piece 69 constituting a lower edge portion of the upper panel 62 is adhered to the inner joint piece 18 of the inner panel 10. An internal space is formed between the upper panel 62 and the inner panel 10 joined in this manner.

[0057] The lower panel 64 is provided to face the lower part of the inner panel 10. A lamp unit mounting portion 67 is provided on both left and right sides of the lower panel 64. A rear lamp unit 94 is attached to the lamp unit mounting portion 67. For example, the rear lamp unit 94 is fastened together at multiple points from the front to the outer joint piece 22 of the inner panel 10 and the lower panel 64 using fasteners 96 such as nuts.

[0058] A plate mounting portion 70 is provided in the center of the lower panel 64. A license plate (number plate) (not shown) is attached to the plate mounting portion 70. A lower joint piece 72 is provided at the upper edge of the lower panel 64. The lower joint piece 72 is located forward via a step portion that extends in the front-to-rear direction. The lower joint piece 72 extends over the entire upper edge of the lower panel 64 in the left-to-right direction.

[0059] The outer edge portion of the lower panel 64 is joined to the inner panel 10 using an adhesive. Specifically, the lower joint piece 72 constituting the upper edge portion of the lower panel 64 is adhered to the inner joint piece 18 of the inner panel 10. The left and right edge portions and the lower edge portion of the lower panel 64 are adhered to the outer joint piece 22 of the inner panel 10. An internal space is formed between the lower panel 64 and the inner panel 10 joined in this manner.

[0060] <Window Panel> The window panel 80 is a horizontally long panel extending across both the left and right ends of the back door 1. The window panel 80 is disposed between the upper panel 62 and the lower panel 64 to close the window opening 11 of the inner panel 10 and cover the opening of the pillar portion 14 of the inner panel 10. The window panel 80 is made of transparent resin such as polycarbonate (PC) or glass. Although not shown, a concealing layer made of black ceramics or the like is provided on the outer periphery of the window panel 80 to conceal the joint portion with the outer panel 60.

[0061] An outer edge portion of the window panel 80 is joined to the outer panel 60 and the inner panel 10 using an adhesive. Specifically, an upper edge portion of the window panel 80 is adhered to an upper joint piece 69 of the upper panel 62. A lower edge portion of the window panel 80 is adhered to a lower joint piece 72 of the lower panel 64. Both left and right edge portions of the window panel 80 are adhered to outer joint pieces 22 between the upper panel 62 and the lower panel 64 of the inner panel 10. An internal space is formed between the window panel 80 and the pillar portion 14 of the inner panel 10 joined in this manner.

[0062] A harness that supplies power to lamp units 90 such as a high mount stop lamp unit 92 and a rear lamp unit 94 is laid in the internal space between the above-mentioned outer panel 60 and window panel 80 and the inner panel 10. The harness is led into the internal space from an opening 37 formed in the outer standing wall 20 at the upper edge of the inner panel 10 through a grommet (not shown).

[0063] <Belt-shaped holding structure> As shown in Fig. 4, the band-shaped holding structure is provided in the portion of the inner panel 10 where the upper reinforcement 50A is inserted, that is, in the portion extending from both the left and right sides of the upper frame portion 13 to a position below the pillar portion 14. The band-shaped holding structure is constituted by a plurality of band-shaped resin portions 43. The upper reinforcement 50A is positioned biased toward the back surface side of the inner panel 10. As shown in Figs. 4 to 7, the panel main body 40 has a front resin layer 41 and a plurality of band-shaped resin portions 43 in the portion where the upper reinforcement 50A is inserted.

[0064] The front-side resin layer 41 covers substantially the entire front surface side of the upper reinforcement 50A. The plurality of strip-shaped resin parts 43 are provided on the back surface side of the upper reinforcement 50A. Each of the plurality of strip-shaped resin parts 43 extends in a strip shape having a flat cross-sectional shape as shown in FIG. 8, and contacts the back surface of the upper reinforcement 50A on one side surface in the thickness direction. Each strip-shaped resin part 43 is connected to the front-side resin layer 41 at least on both ends. The upper reinforcement 50A is held to the panel main body 40 by the plurality of strip-shaped resin parts 43.

[0065] 4, the strip-shaped resin portion 43 includes a plurality of first strip-shaped resin portions 43A and a plurality of second strip-shaped resin portions 43B. The first strip-shaped resin portions 43A each extend along the circumferential direction of the window frame portion 12 and are positioned at intervals from one another in the width direction of the window frame portion 12. The second strip-shaped resin portions 43B extend in a direction intersecting the first strip-shaped resin portion 43A and are positioned at intervals from one another in the circumferential direction of the window frame portion 12.

[0066] The first band-shaped resin portion 43A and the second band-shaped resin portion 43B are integrally formed to constitute the net portion 45. The net portion 45 covers the back surface side of the upper reinforcement 50A in a net-like manner. The upper reinforcement 50A is partially exposed on the back surface side from the panel main body 40 at the mesh portion of the net portion 45. In addition, the back surface of the outer edge portion of the upper reinforcement 50A located on the upper frame portion 13 is covered by the panel main body 40.

[0067] A portion of upper reinforcement 50A corresponding to hinge mounting portion 24 and a portion corresponding to stay mounting portion 25 are exposed on the back surface side from panel main body 40. A first nut 51 for fastening hinge 100 is welded to the exposed portion corresponding to hinge mounting portion 24 on the back surface of upper reinforcement 50A. In addition, a second nut 52 for fastening damper stay 110 is welded to the exposed portion corresponding to stay mounting portion 25 on the back surface of upper reinforcement 50A.

[0068] 6 and 7, a portion of the upper reinforcement 50A located at the pillar portion 14 extends along the longitudinal direction of the pillar portion 14 and forms a recessed portion 54 that is open to the back side. A step portion 55 that deepens the inner portion in the vehicle width direction is formed at the bottom of the recessed portion 54 of the upper reinforcement 50A. The recessed portion 54 is formed with a first corner portion 57a ​​that is convex toward the back side of the inner panel 10 and three second corner portions 57b that are convex toward the front side of the inner panel 10.

[0069] The first strip-shaped resin portion 43A covers the corner portion 57 of the recessed portion 54. Specifically, the first strip-shaped resin portion 43A is provided for each second corner portion 57b. The first strip-shaped resin portion 43A extends along each second corner portion 57b and covers the corresponding second corner portion 57b. Each first strip-shaped resin portion 43A contacts the second corner portion 57b of the recessed portion 54 at a side surface and extends in the width direction to correspond to one surface continuous with the second corner portion 57b.

[0070] The width direction of each of the first strip-shaped resin portions 43A extending from both ends in the vehicle width direction of the bottom of the recessed portion 54 corresponds to the height direction of the side walls of the recessed portion 54. The width direction of the first strip-shaped resin portion 43A extending through the middle in the vehicle width direction of the bottom of the recessed portion 54 corresponds to the width direction of the recessed portion 54. A through hole 59 is formed in a portion of the upper reinforcement 50A corresponding to the portion where the first strip-shaped resin portion 43A and each of the second strip-shaped resin portions 43B intersect. The net portion 45 and the front-side resin layer 41 are connected via the through hole 59.

[0071] 5, reinforcing ribs 28 are provided on the back surface of each of the second belt-shaped resin portions 43B provided on the upper frame portion 13 of the inner panel 10. Of the multiple reinforcing ribs 28, all of the reinforcing ribs 28 located in the portion where the upper reinforcement 50A is inserted are formed integrally with the second belt-shaped resin portion 43B. Each of the reinforcing ribs 28 is connected to the outer periphery of the upper reinforcement 50A in the panel main body 40, specifically, to the inner standing wall 16.

[0072] Furthermore, a reinforcing rib 28 is also provided on the back surface of the first strip-shaped resin portion 43A provided on the upper frame portion 13 of the inner panel 10. This reinforcing rib 28 connects the reinforcing ribs 28 provided on the back surface of the second strip-shaped resin portion 43B to each other. The first strip-shaped resin portion 43A and the second strip-shaped resin portion 43B, on whose back surfaces the reinforcing rib 28 is provided, are formed wider than the base end of the reinforcing rib 28. The width w1 of the strip-shaped resin portion 43 is, for example, 2 mm to 15 mm (see FIG. 8). The thickness t1 of the strip-shaped resin portion 43 is, for example, 1 mm to 5 mm. The thickness t2 of the front-side resin layer 41 is, for example, 1.5 mm to 3 mm.

[0073] -Inner panel molding method- The inner panel 10 of this embodiment is molded using an injection molding die 200 shown in FIG.

[0074] <Injection mold> The injection molding die 200 includes a core die 210 and a cavity die 220. The core die 210 has a first molding surface 212 that molds the back surface of the inner panel 10. The cavity die 220 has a second molding surface 222 that molds the front surface of the inner panel 10. The core die 210 and the cavity die 220 are clamped together to form a cavity 230 between them for molding the panel body 40.

[0075] The cavity 230 is a molding space having a shape corresponding to the panel main body 40. The cavity 230 includes a first space portion 232 and a second space portion 234. The first space portion 232 is a space portion in which the upper reinforcement 50A is not located (i.e., the upper reinforcement 50A is not set in the thickness direction of the panel main body 40 to be molded). The second space portion 234 is a space portion in which the upper reinforcement 50A is located (i.e., the upper reinforcement 50A is set in the thickness direction of the panel main body 40 to be molded).

[0076] A first magnet 214 and a second magnet 216 are incorporated into the core mold 210. A plurality of the first magnets 214 are provided in a first set portion 217 in which the upper reinforcement 50A of the core mold 210 is set. Specifically, a plurality of the first magnets 214 (four in the illustrated example) are provided in the first set portion 217 at positions corresponding to the upper portion of the upper reinforcement 50A, and one is provided in a position corresponding to the lower portion of the upper reinforcement 50A. A plurality of the second magnets 216 (two in the illustrated example) are provided in a second set portion 218 in which the lower reinforcement 50B of the core mold 210 is set.

[0077] A plurality of gates G are formed on the second molding surface 222 of the cavity mold 220. The gates G are inlets for injecting the molten resin R, which is the raw material of the panel main body 40, into the cavity 230. The plurality of gates G are set at intervals on the outer periphery and inner periphery of the cavity 230, respectively. The gates G include, for example, a first gate G1, a second gate G2, a third gate G3, a fourth gate G4, and a fifth gate G5. Each of the first to fifth gates G5 is a side gate.

[0078] The first gates G1 are provided on the outer periphery and inner periphery of the portions of the cavity 230 that form the central portion in the left-right direction of the upper frame portion 13 of the panel main body 40. The second gates G2 are provided on the outer periphery of the portions of the cavity 230 that form both sides in the left-right direction of the upper frame portion 13 of the panel main body 40. Directly below the second gates G2 are portions of the cavity 230 that form the strip-shaped resin portion 43 and the reinforcing rib 28 on the end portion located on the upper frame portion 13 of the upper reinforcement 50A.

[0079] The third gate G3 is provided on the inner periphery of the cavity 230 at a portion where both pillar portions 14 of the panel main body 40 are to be formed. The fourth gate G4 is provided on the outer periphery and inner periphery of the cavity 230 at a portion where the central portion in the left-right direction of the lower part of the panel main body 40 is to be formed. The fifth gate G5 is provided on the outer periphery and inner periphery of the cavity 230 at a portion where both sides in the left-right direction of the lower part of the panel main body 40 are to be formed.

[0080] The cavity mold 220 is further provided with a hot runner 224 communicating with each gate G, and a sprue (not shown) communicating with the hot runner 224. The hot runner 224 has a plurality of branch portions 228 extending from each gate G via a gate runner 226. Each branch portion 228 is provided with a needle valve (not shown) that controls the opening and closing of the corresponding gate G. The sprue opens to the outer surface of the cavity mold 220.

[0081] The sprue is connected to a nozzle of a resin injector (not shown). The resin injector injects molten resin R, which has been heated and softened, from the nozzle into the injection molding die 200. The molten resin R is a thermoplastic resin in a molten state. The molten resin R injected from the resin injector is sent from the sprue through a hot runner 224 to each gate G. The injection timing of the molten resin R from each gate G to the cavity 230 is controlled by opening and closing a needle valve.

[0082] <Inner panel molding process> The method for molding the inner panel 10 includes a setting step, a mold clamping step, an injection molding step, and a demolding step.

[0083] First, in the setting step, a pair of upper reinforcement 50A and lower reinforcement 50B are set in the injection molding die 200 in an open state in which the core die 210 and the cavity die 220 are separated from each other, as shown in Fig. 9. Each upper reinforcement 50A is attracted and held by the first set portion 217 of the core die 210 due to the magnetic force of a plurality of first magnets 214. Also, the lower reinforcement 50B is attracted and held by the second set portion 218 of the core die 210 due to the magnetic force of a plurality of second magnets 216. At this time, each upper reinforcement 50A and lower reinforcement 50B is in contact with the core die 210 at the back surface.

[0084] In the mold clamping process that follows, the core mold 210 is brought close to the cavity mold 220 to close the injection molding mold 200, and then the injection molding mold 200 is clamped up to clamp the mold. This forms a cavity 230 inside the injection molding mold 200. The cavity 230 is formed so as to be continuous with a predetermined boundary region 236 corresponding to the peripheral portion of each upper reinforcement 50A, specifically, the boundary region 236 located at the location where the upper frame portion 13 of the panel main body 40 is formed, and mainly on the front side of the upper reinforcement 50A around the boundary region 236 (see FIG. 13). At this time, the needle valves of all the gates G are closed.

[0085] In the subsequent injection molding process, injection of molten resin R is started from the nozzle of the resin injector. Then, the needle valves corresponding to the gates G are opened at a predetermined timing, and the molten resin R sent from the resin injector is injected from each gate G into the cavity 230. The multiple gates G are opened in the order of, for example, the first gate G1, the second gate G2, the fourth gate G4, the fifth gate G5, and the third gate G3, and the molten resin R is injected into the cavity 230 in that order.

[0086] First, the first gate G1 is opened, and molten resin R is injected from the first gate G1 into the first space 232. The molten resin R injected from the first gate G1 flows and spreads in the first space 232 as shown in Fig. 10, and flows into the second space 234 through the boundary area 236 as shown in Fig. 11. At this time, as shown in Fig. 13, the molten resin R injected from the first gate G1 flows onto the front side of the upper reinforcement 50A, and presses and fixes the upper reinforcement 50A to the core mold 210.

[0087] In this way, the molten resin R injected from the first gate G1 into the first space 232 flows into the second space 234, and then the second gate G2 is opened and the molten resin R is injected from the second gate G2 into the second space 234. At this time, as shown in Figures 14 and 15, the molten resin R injected from the second gate G2 flows separately onto the front side and back side of the upper reinforcement 50A, but since the upper reinforcement 50A is fixed by the molten resin R injected from the first gate G1, it is unlikely to become displaced even when it receives the pressure of the molten resin R injected from the second gate G2.

[0088] The molten resin R injected from the second gate G2 is distributed and flows quickly to the portion of the cavity 230 where the band-shaped resin portion 43 is to be formed on the back side of the upper reinforcement 50A. Injection of the molten resin R from the second gate G2 starts after the molten resin R injected from the first gate G1 reaches the front side of the portion of the cavity 230 where the reinforcing rib 28 is to be formed, located directly below the second gate G2. In this way, the molten resin R injected from the first gate G1 and flowing to the front side of the upper reinforcement 50A serves as a support against the pressure of the molten resin R injected from the second gate G2 and flowing to the portion of the cavity 230 where the band-shaped resin portion 43 is to be formed.

[0089] The injection of the molten resin R from the first gate G1 is stopped by closing the first gate G1 at the timing when the molten resin R injected from the first gate G1 into the first space 232 flows into the second space 234 through the boundary area 236. The timing to stop the injection of the molten resin R from the first gate G1 may be the same as or may be shifted from the timing to start the injection of the molten resin R from the second gate G2.

[0090] 12, the molten resin R injected from the second gate G2 flows through the second space 234 and spreads to the portion of the cavity 230 that will form the pillar portion 14. Then, when the molten resin R injected from the second gate G2 into the second space 234 flows into the periphery of the third gate G3, the third gate G3 is opened and the molten resin R is injected from the third gate G3 into the second space 234. The molten resin R injected from the third gate G3 flows through the second space 234 so as to spread toward the portion of the cavity 230 that will form the lower portion of the inner panel 10.

[0091] The injection of the molten resin R from the second gate G2 is stopped by closing the second gate G2 at the timing when the molten resin R injected from the second gate G2 into the second space portion 234 flows into the periphery of the third gate G3. The timing to stop the injection of the molten resin R from the second gate G2 may be the same as the timing to start the injection of the molten resin R from the third gate G3, or may be shifted.

[0092] After starting the injection of the molten resin R from the second gate G2, or simultaneously with the injection of the molten resin R from the second gate G2, the fourth gate G4 is opened, and the molten resin R is injected from the fourth gate G4 into the first space 232. The molten resin R injected from the fourth gate G4 flows through the first space 232 and spreads on both the left and right sides of the portion forming the lower part of the inner panel 10 of the cavity 230. When the molten resin R injected from the fourth gate G4 into the first space 232 flows into the periphery of the fifth gate G5, the fifth gate G5 is opened, and the molten resin R is injected from the fifth gate G5 into the first space 232. The molten resin R injected from the fifth gate G5 flows through the first space 232 so as to spread outward in the direction corresponding to the vehicle width direction of the portion forming the lower part of the inner panel 10.

[0093] The injection of the molten resin R from the fourth gate G4 is stopped by closing the fourth gate G4 at the timing when the molten resin R injected from the fourth gate G4 into the first space portion 232 flows into the periphery of the fifth gate G5. The timing to stop the injection of the molten resin R from the fourth gate G4 may be the same as or may be shifted from the timing to start the injection of the molten resin R from the fifth gate G5.

[0094] The timing for opening the third gate G3 and the fifth gate G5 is adjusted so that the molten resin R injected from the third gate G3 into the second space 234 and the molten resin R injected from the fifth gate G5 into the first space 232 join together at locations (locations indicated by two-dot chain lines in FIG. 12) that form portions near the pillars 14 in the lower part of the panel main body 40. The molten resin R injected from each gate G in this manner flows and spreads in the cavity 230, filling the entire cavity 230.

[0095] When the entire cavity 230 is filled with the molten resin R, the injection of the molten resin R from the resin injector is stopped and all gates G are closed. Then, cooling of the injection molding die 200 is started. The molten resin R filled in the cavity 230 is solidified by cooling the injection molding die 200. By solidifying the molten resin R in the cavity 230 in this manner, the panel main body 40 is molded integrally with the pair of upper reinforcement 50A and lower reinforcement 50B.

[0096] In the demolding process that follows, the injection molding die 200 is opened and the core die 210 is separated from the cavity die 220. Furthermore, an ejector pin (not shown) provided on the core die 210 is caused to protrude from the first molding surface 212, whereby the inner panel 10, in which the pair of upper reinforcements 50A and lower reinforcements 50B and the panel main body 40 are integrated, is detached from the first molding surface 212 of the core die 210, and the inner panel 10 is taken out from the injection molding die 200. Thereafter, post-processing such as cutting off gate residue remaining on the inner panel 10 is performed.

[0097] In this manner, the inner panel 10 can be formed.

[0098] -Features of the embodiment- In the inner panel 10 of this embodiment, the metal upper reinforcement 50A inserted into the resin panel main body 40 is held by a plurality of strip-shaped resin parts 43 provided on the back side thereof. Both ends of each strip-shaped resin part 43 are connected to the front side resin layer 41 covering the front side of the upper reinforcement 50A. This allows the panel main body 40 to firmly hold the upper reinforcement 50A by the plurality of strip-shaped resin parts 43. Furthermore, each strip-shaped resin part 43 extends in a strip shape so as to have a flat cross-sectional shape, and contacts the back side of the upper reinforcement 50A with one main surface in the thickness direction. This makes it possible to suppress deformation of the upper reinforcement 50A under the pressure of the molten resin R injected into the cavity 230 of the injection molding die 200 when the inner panel 10 is injection molded, even if a relatively thin upper reinforcement 50A is used.

[0099] In the inner panel 10 of this embodiment, the upper reinforcement 50A is inserted into the panel body 40 in a manner that a portion of the upper reinforcement 50A is exposed on the back surface side of the panel body 40. This makes it possible to suppress an increase in weight of the inner panel 10, while reinforcing the pillar portion 14 with the upper reinforcement 50A, thereby suppressing deformation of the pillar portion 14.

[0100] In the inner panel 10 of this embodiment, the back side of the upper reinforcement 50A is covered by a net portion 45 configured by integrally forming the first strip-shaped resin portion 43A and the second strip-shaped resin portion 43B. When the back door 1 is opened or closed, a load accompanying the opening and closing operation is applied to the inner panel 10, and the upper reinforcement 50A tries to peel off from the front-side resin layer 41. At this time, the force that tries to peel off the upper reinforcement 50A is dispersed to the net portion 45. Therefore, the panel main body 40 can favorably hold the upper reinforcement 50A by the multiple strip-shaped resin portions 43.

[0101] In the inner panel 10 of this embodiment, a portion of the upper reinforcement 50A located at the pillar portion 14 constitutes a recessed portion 54, and a corner portion 57 of the recessed portion 54 is covered by the first strip-shaped resin portion 43A. This reinforces the corner portion 57 of the upper reinforcement 50A. This improves the rigidity of the pillar portion 14. Even if the shape accuracy of the corner portion 57 of the upper reinforcement 50A is poor, the corner portion 57 of the upper reinforcement 50A does not interfere with the core mold 210 of the injection molding die 200 when the inner panel 10 is molded. This improves the accuracy of the insert position of the upper reinforcement 50A.

[0102] In the inner panel 10 of this embodiment, the first strip-shaped resin portion 43A extends in the width direction to correspond to one surface continuing to the corner portion 57 of the recessed portion 54 of the upper reinforcement 50A. This prevents the first strip-shaped resin portion 43A from becoming thick at the corner portion 57 of the upper reinforcement 50A, and allows the first strip-shaped resin portion 43A to be formed to have a flat cross-sectional shape. This makes it possible to suppress deformation caused by the difference in cooling and solidifying time between the first strip-shaped resin portion 43A and the front-side resin layer 41 during molding of the inner panel 10.

[0103] In the inner panel 10 of this embodiment, the net portion 45 and the front-side resin layer 41 are connected via through-holes 59 formed in the upper reinforcement at positions corresponding to the intersections of the first strip-shaped resin portion 43A and the second strip-shaped resin portion 43B. This allows the panel body 40 to firmly hold the upper reinforcement 50A by the multiple strip-shaped resin portions 43.

[0104] In the inner panel 10 of this embodiment, the reinforcing rib 28 is provided on the back surface of the strip-shaped resin portion 43. When the reinforcing rib 28 is provided upright directly on the back surface of the upper reinforcement 50A at a location different from the strip-shaped resin portion 43, the area of ​​the resin portion constituting the reinforcing rib 28 in contact with the reinforcing panel 50 becomes relatively narrow. In contrast, when the reinforcing rib 28 is provided upright on the strip-shaped resin portion 43, the area of ​​the resin portion constituting the reinforcing rib 28 in contact with the upper reinforcement 50A can be secured by the strip-shaped resin portion 43. Furthermore, since the reinforcing rib 28 is connected to the outer periphery of the upper reinforcement 50A in the panel main body 40, the reinforcing rib 28 is unlikely to be taken up by the core mold when demolding in the manufacture of the inner panel 10. This is advantageous in increasing the rigidity of the inner panel 10 by providing a relatively high reinforcing rib 28.

[0105] In the inner panel 10 of this embodiment, the strip-shaped resin portion 43 is formed with a width of 15 mm or less. If the width of the strip-shaped resin portion 43 is 15 mm or less, even if a lightweight and inexpensive pressed iron plate with a thickness of, for example, about 0.5 mm to 0.6 mm is used as the upper reinforcement 50A, it is possible to prevent the upper reinforcement 50A from being deformed by the pressure of the resin when the inner panel 10 is molded. This is advantageous for reducing the weight and cost of the vehicle back door 1.

[0106] The vehicle back door 1 of this embodiment includes the above-mentioned inner panel 10. The inner panel 10 can suppress deformation during molding of the panel body 40 even if the inserted upper reinforcement 50A is relatively thin. Therefore, by adopting a relatively thin upper reinforcement 50A, the weight of the back door 1 can be reduced while maintaining the quality of the inner panel 10.

[0107] In the molding method of the inner panel 10 of this embodiment, in the injection molding process, the molten resin R injected from the first gate G1 into the first space 232 where the upper reinforcement 50A is not located flows through a predetermined boundary portion 236 corresponding to the peripheral portion of the upper reinforcement 50A into the second space 234 where the upper reinforcement 50A is located, and then injection of the molten resin R from the second gate G2 begins into the second space 234. In this way, the molten resin R injected from the first gate G1 and flowing into the front side of the reinforcement panel 50 in the second space 234 presses the upper reinforcement 50A against the core mold 210 before the molten resin R is injected from the second gate G2, and serves as a support against the pressure of the molten resin R filled in the space portion for molding the strip-shaped resin portion 43.

[0108] As a result, when molding the inner panel 10, the upper reinforcement 50A can be inserted into a predetermined position in the panel main body 40 without supporting the upper reinforcement 50A by a positioning pin in the cavity 230 of the injection molding die 200. This is advantageous in improving the appearance of the inner panel 10, since no pressing marks are left on the panel main body 40. In addition, since a drive mechanism for moving the positioning pins and a resin sensor for controlling the operation timing of the drive mechanism are not required, the mold structure of the injection molding die 200 is not complicated.

[0109] In the molding method of the inner panel 10 of this embodiment, in the injection molding process, the injection of the molten resin R from the first gate G1 is stopped at the timing when the molten resin R injected from the first gate G1 into the first space 232 flows into the second space 234 through the boundary portion 236. By doing so, the filling range of the molten resin R injected from the first gate G1 in the cavity 230 is narrowed. If the filling range of the molten resin R injected from the first gate G1 in the cavity 230 is wide, the injection pressure of the molten resin R from the first gate G1 becomes high. If the injection pressure of the molten resin R becomes excessively high, it will cause burrs to occur. On the other hand, by narrowing the filling range of the molten resin R injected from the first gate G1 in the cavity 230, it is possible to prevent the injection pressure of the molten resin R from the first gate G1 from becoming excessively high, and suppress the occurrence of burrs.

[0110] Other Embodiments In the above embodiment, a pair of upper reinforcements 50A are inserted from both the left and right sides of the upper frame portion 13 of the inner panel 10 along the pillar portions 14, but this is not limiting. The upper reinforcement 50A may be an integrated upper reinforcement 50A connected along the upper frame portion 13, rather than a pair separated on the left and right.

[0111] In the above embodiment, the plurality of strip-shaped resin parts 43 constitute the net part 45, but the present invention is not limited to this. For example, all of the plurality of strip-shaped resin parts 43 may be the first strip-shaped resin parts 43A or the second strip-shaped resin parts 43B. In short, it is sufficient that the upper reinforcement 50A is held to the panel main body 40 by the plurality of strip-shaped resin parts 43 and is partially exposed from the panel main body 40 to the back surface side.

[0112] In the above embodiment, the outer panel 60 is configured with two separate bodies, the upper panel 62 and the lower panel 64, but this is not limited thereto. The outer panel 60 may be configured as a single panel. Also, although the window panel 80 is described as a panel separate from the outer panel 60, it may be integrated with the outer panel 60, that is, it may be configured as a part of the outer panel 60.

[0113] As described above, a preferred embodiment has been described as an example of the present invention. However, the present invention is not limited to this, and can be applied to embodiments in which appropriate changes, substitutions, additions, omissions, etc. are made. It will be understood by those skilled in the art that various further modifications are possible for the above embodiment without departing from the spirit of the present invention, and that such modifications also fall within the scope of the technology disclosed herein.

[0114] Note that the descriptions "first," "second," etc., mentioned above are merely used to distinguish the words to which they are attached, and do not limit the number or order of the words. Also, the description "~" in the numerical ranges mentioned above means a range that includes the numerical values ​​before and after it. In other words, if X and Y are substituted for numerical values, then the description "X~Y" indicates a range of "greater than or equal to X and less than or equal to Y." [Industrial Applicability]

[0115] INDUSTRIAL APPLICABILITY As described above, the present invention is useful for an inner panel, a vehicle back door, and a method for molding an inner panel. [Explanation of symbols]

[0116] G1 First Gate G2 2nd Gate R Molten resin 5 Door body 10 Inner Panel 11 Window opening 12 Window frame 13 Upper frame 14 Pillar section 28 Reinforcing rib 37 Aperture 40 Panel body 41 Surface resin layer 43 Resin strip 43A 1st Resin Strip 43B Second band-shaped resin part 45 Net Club 50 Reinforcement Panel 54 Concave part 57 Corner part 59 Through hole 60 Outer Panel 200 injection mold 230 Cavity 232 1st space part 234 Second space 236 Boundary site

Claims

1. An inner panel having a window opening (11) formed in an upper half portion thereof and constituting a vehicle back door (1) in combination with an outer panel (60), a resin panel body (40) having the window opening (11); and a metal reinforcing panel (50) inserted along a pillar portion (14) from both left and right portions of an upper frame portion (13) of a window frame portion (12) that forms an outer periphery of the window opening (11) in the panel body (40), The panel body (40) has a front resin layer (41) covering a front surface side of the reinforcing panel (50) and a plurality of strip-shaped resin portions (43) provided on a back surface side of the reinforcing panel (50), Each of the plurality of strip-shaped resin portions (43) extends in a strip shape having a flat cross-sectional shape, has one main surface in the thickness direction in contact with the rear surface of the reinforcing panel (50), and is connected to the front-side resin layer (41) at least at both ends. The reinforcing panel (50) is held to the panel body (40) by the plurality of strip-shaped resin portions (43) and is partially exposed on the rear surface side of the panel body (40). An inner panel characterized by:

2. The inner panel according to claim 1, The strip-shaped resin portion (43) may be a plurality of first strip-shaped resin portions (43A) extending along a circumferential direction of the window frame portion (12); a plurality of second strip-shaped resin portions (43B) extending in a direction intersecting the first strip-shaped resin portion (43A) and positioned at intervals from one another in the circumferential direction of the window frame portion (12), The first strip-shaped resin portion (43A) and the second strip-shaped resin portion (43B) are integrally formed to constitute a net portion (45) that covers the rear surface side of the reinforcing panel (50) in a net-like manner. An inner panel characterized by:

3. The inner panel according to claim 2, a portion of the reinforcing panel (50) located on the pillar portion (14) defines a recessed portion (54) extending along the longitudinal direction of the pillar portion (14) and opening to a rear surface side, The first strip-shaped resin portion (43A) covers a corner portion (57) of the recessed portion (54). An inner panel characterized by:

4. The inner panel according to claim 3, The first strip-shaped resin portion (43A) contacts the corner portion (57) of the recessed portion (54) at a side surface thereof and extends in a width direction corresponding to one surface of the recessed portion (54) that is continuous with the corner portion (57). An inner panel characterized by:

5. The inner panel according to claim 2, a through hole (59) is formed in a portion of the reinforcing panel (50) corresponding to an intersection between the first strip-shaped resin portion (43A) and the second strip-shaped resin portion (43B); The net portion (45) and the surface resin layer (41) are connected to each other via the through-holes (59). An inner panel characterized by:

6. The inner panel according to claim 1, A reinforcing rib (28) is provided on the back surface of the strip-shaped resin portion (43), The reinforcing rib (28) is connected to the outer periphery of the reinforcing panel (50) in the panel body (40). An inner panel characterized by:

7. The inner panel according to claim 1, The width of the strip-shaped resin portion (43) is 15 mm or less. An inner panel characterized by:

8. An inner panel (10) according to any one of claims 1 to 7; and an outer panel (60) joined to the inner panel (10) to form a door body (5). A vehicle back door.

9. A method for molding the inner panel (10) according to any one of claims 1 to 7, comprising the steps of: a setting step of setting the reinforcing panel (50) in a state where the back surface of the reinforcing panel (50) is in contact with an injection molding die (200); a mold clamping process for clamping the injection molding die (200) to form a cavity (230) for molding the panel body (40) inside the injection molding die (200) at a predetermined boundary region (236) corresponding to a peripheral portion of the reinforcing panel (50) and around the boundary region (236) so as to be continuous with the front side of the reinforcing panel (50); an injection molding step of injecting and filling the cavity (230) with molten resin (R) and then solidifying the molten resin to mold the panel body (40) integrally with the reinforcing panel (50); As the injection molding die (200), a first space portion (232) of the cavity (230) in which the reinforcing panel (50) is not located and a second space portion (234) in which the reinforcing panel (50) is located are located via the boundary portion (236), and the injection molding die (200) is provided with a first gate (G1) opening toward the first space portion (232) and a second gate (G2) opening toward the second space portion (234), In the injection molding process, the molten resin (R) injected from the first gate (G1) into the first space (232) flows into the second space (234) through the boundary portion (236), and then the molten resin (R) is injected into the second space (234) from the second gate (G2). A method for forming an inner panel comprising the steps of:

10. The method for forming an inner panel according to claim 9, In the injection molding step, the injection of the molten resin (R) from the first gate (G1) is stopped at a timing when the molten resin (R) injected from the first gate (G1) into the first space portion (232) flows into the second space portion (234) through the boundary portion (236). A method for forming an inner panel comprising the steps of:

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