Resin outer panel member

Abstract

To provide a resin outer panel member capable of preventing the occurrence of a poor appearance caused by thermal strain irrespective of its shape or a fixing form with an inner panel member.SOLUTION: A resin outer panel member 10 constituting an appearance of a vehicle with an inner panel member comprises: a regulation region 13 regulated in elongation in a direction along a surface in a state where a part of a peripheral edge is fixed to the peripheral edge of the inner panel member; and a folding part 16 provided at a position sandwiching a part 14 of the peripheral edge of the regulation region 13 fixed to the inner panel member and the center 13a of the regulation region 13 and formed into a shape folded toward the center 13a of the regulation region 13. A protrusion 17 extending in the width direction of the folding part 16 is provided between the part 14 fixed to the inner panel member and the folding part 16 on the non-design surface 13b side of the regulation region 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a resin outer panel member, and more particularly to a technique for suppressing deformation of a resin outer panel member due to thermal stress. [Background technology]

[0002] In recent years, as part of efforts to reduce environmental impact by improving fuel efficiency in vehicle tailgates such as automobiles, at least one of the tailgate outer and tailgate inner components that make up the tailgate has been formed from resin, which is lighter than metal (see, for example, Patent Document 1).

[0003] In this case, the back door outer is adhesively fixed to the peripheral edge of the back door inner in order to simultaneously provide a sealing structure and a fixing structure (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-124346 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-167697 Summary of the Invention [Problem to be solved by the invention]

[0005] Since the tailgate outer is located on the outer surface of the vehicle, it is more likely to become hot than the tailgate inner. For example, if a vehicle is left in the scorching sun for a long period of time in midsummer, the temperature of the tailgate outer (particularly the top surface of the tailgate outer upper) can reach 80 to 100°C. In such a high temperature, the tailgate outer attempts to thermally expand. However, if the tailgate outer is adhesively fixed to the peripheral edge of the tailgate inner as described above, the adhesive fixation restricts deformation along its plane, resulting in thermal stress. In particular, if the tailgate outer is made of resin, the amount of thermal expansion increases compared to a metal tailgate. Furthermore, if a rear spoiler is integrally formed with the tailgate outer, the rear end of the top surface of the tailgate outer upper that constitutes the rear spoiler will be folded forward. This portion has high geometric rigidity (resistance to deformation due to its shape) and is likely to become a starting point for stress concentration. Therefore, if the thermal stress (thermal strain) generated in the back door outer increases beyond a predetermined level, it may cause deformation (poor appearance) such that the top surface of the back door outer upper becomes wavy and concave along its width direction.

[0006] In view of the above circumstances, the technical problem to be solved in this specification is to provide a resin outer panel member that can prevent poor appearance due to thermal distortion regardless of its shape or the manner in which it is fixed to the inner panel member. [Means for solving the problem]

[0007] The above-mentioned problem is solved by the resin outer panel member of the present invention. Specifically, this outer panel member is a resin outer panel member that, together with an inner panel member, constitutes an exterior part of a vehicle. It is characterized by having a regulated region in which stretching along the surface is restricted when a portion of the peripheral edge is fixed to the inner panel member, and a folded portion that is located between the portion of the peripheral edge of the regulated region fixed to the inner panel member and the center of the regulated region and is folded back toward the center of the regulated region. A protrusion extending in the width direction of the folded portion is provided on the non-design surface side of the regulated region between the portion fixed to the inner panel member and the folded portion. Note that the "width direction of the folded portion" here refers to a direction perpendicular to the folding direction of the folded portion. Furthermore, "extending in the width direction" here does not only refer to a shape extending completely parallel to the width direction, but also includes a shape extending in the width direction orthogonal to the width direction.

[0008] The inventors conducted thermal stress analysis of a resin outer panel under specified constraint conditions to examine its deformation. The results showed that, within the peripheral edge of the region where elongation along the surface is restricted when the outer panel is fixed to the inner panel, stress concentrations are particularly pronounced in the region fixed to the inner panel along the peripheral edge, and in or near the folded portion located between the fixed portion and the center of the restricted region. Furthermore, when stresses in both regions increase to a level where they mutually affect each other, the stress concentration region expands across the center of the restricted region, resulting in thermal distortion that could lead to concave deformation. In light of these findings, the present invention provides a protrusion extending in the width direction of the folded portion between the fixed portion and the folded portion, which is the origin of stress concentration. This configuration provides a region of high geometric rigidity between the fixed portion and the folded portion, thereby minimizing the possibility of the two stress concentration regions joining together across the center of the restricted region. Furthermore, by providing a new portion with high shape rigidity, the stress distribution in the entire restriction area, including the peripheral edge portion, is made uniform, which makes it possible to alleviate stress concentration in each stress concentration portion (fixing portion, folded portion).As described above, according to the present invention, it is possible to suppress an increase in thermal distortion in the center portion of the restriction area and prevent deformation of the restriction area to a level that could cause poor appearance.

[0009] Furthermore, the resin outer panel member described above can prevent poor appearance due to thermal distortion regardless of its shape or the manner in which it is fixed to the inner panel member, and therefore can be suitably provided, for example, as a resin tailgate outer upper in which a restriction area is provided on the top surface of the tailgate outer upper and the rear end of a rear spoiler is provided on the rear end side of the top surface as a folded portion.

[0010] In this case, it is preferable that the protrusion portion is provided at a position where the distance from the peripheral edge of the regulating member, which is fixed to the back door inner as an inner panel member, is 10% or more of the front-to-rear dimension of the entire top surface portion.

[0011] The inventors further conducted a thermal stress analysis of a plastic back door outer upper to verify the preferred range for the longitudinal distance of the protrusion from the portion fixed to the back door inner panel as an inner panel member. As a result, it was found that the stress isolation effect of providing the protrusion can be effectively achieved when the protrusion is provided at a position that is approximately 10% or more away from the portion fixed to the back door inner panel as a percentage of the longitudinal dimension of the entire top surface. Therefore, by providing the protrusion at a position that is 10% or more away from the portion fixed to the back door inner panel as a percentage of the longitudinal dimension of the entire top surface, it is possible to avoid a situation in which stress concentration areas are connected in the longitudinal direction and to prevent, as much as possible, the occurrence of thermal distortion in the restriction area. [Effects of the Invention]

[0012] As described above, the resin outer panel member according to the present invention can prevent appearance defects due to thermal distortion, regardless of its shape or the manner in which it is fixed to the inner panel member. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a resin back door outer upper according to one embodiment of the present invention. FIG. [Figure 2] FIG. 1 is a plan view of the outer upper back door. [Figure 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a resin outer panel member according to one embodiment of the present invention will be described with reference to the drawings. In this embodiment, the resin outer panel member will be described using an automobile back door outer upper as an example.

[0015] 1 shows a perspective view of a tailgate outer upper 10 according to one embodiment of the present invention. The tailgate outer upper 10 is made of resin and constitutes a tailgate for an automobile together with a tailgate inner (not shown) as an inner panel member, and has a rear spoiler 11 integrally formed therewith.

[0016] In this embodiment, the back door outer upper 10 is fixed to the peripheral edge of the back door inner panel by adhesive or the like. Therefore, almost the entire peripheral edge 10a of the back door outer upper 10 is adhesively fixed to the peripheral edge of the back door inner panel. In this case, the entire top surface 12 of the back door outer upper 10 constitutes the restriction area 13 according to the present invention. In addition, an adhesive fixing portion 14 for connecting to the back door inner panel is provided on the peripheral edge of the top surface 12 at an open-side edge 12a extending in the width direction or in the vicinity thereof (a region slightly inside), and downward bent portions 15 are provided on both sides of the peripheral edge in the width direction. In addition, a folded portion 16 is provided on the peripheral edge of the top surface 12 at a position between the adhesive fixing portion 14 and the central portion 13a of the restriction area 13, the folded portion 16 being folded back toward the central portion 13a of the restriction area 13 (see FIG. 3 described later). This folded portion 16 constitutes the rear end of the rear spoiler 11.

[0017] Also, as shown in Figures 2 and 3, a protrusion portion 17 extending in the width direction of the folded portion 16 (here, the width direction of the back door outer upper 10) is provided on the non-design surface 13b side of the regulated area 13 that forms the top surface portion 12, between the adhesive fixing portion 14 and the folded portion 16.

[0018] The shape of the protrusion 17 is not particularly limited, and any cross-sectional shape can be used. In this embodiment, the protrusion 17 has a shape that tapers from the base end toward the tip end (see FIG. 3). Furthermore, in consideration of the demoldability when the protrusion 17 is formed integrally with the tailgate outer upper 10 by resin injection molding, it is preferable that the protrusion 17 has a shape (draft angle) that matches the demolding direction of the molded product (tailgate outer upper 10), specifically a shape that is inclined forward, as shown in FIG. 3. Of course, the cross-sectional shape or size of the protrusion 17 may be uniform in the longitudinal direction, or may have a predetermined distribution (for example, a shape that tapers toward both ends in the longitudinal direction).

[0019] There is also no particular limitation on the cross-sectional area of ​​the protrusion 17. As long as the above-described stress shielding effect and stress averaging effect can be obtained and as long as spatial constraints such as gaps with adjacent members (such as the back door inner panel) are met, the protrusion 17 can be formed to any size.

[0020] Furthermore, with regard to the widthwise dimension of the protrusions 17, it is essential that they are provided in a range that overlaps, in at least a portion of the widthwise direction, with the stress concentration areas that are expected to occur in the widthwise central region of the adhesive fixing part 14 and the widthwise central region of the folded-back part 16 if the protrusions 17 were not present, and preferably they are provided in a range that overlaps with the stress concentration areas over the entire widthwise region. Note that in this specification, the stress concentration area refers to an area that exhibits a stress concentration coefficient of 2 or more.

[0021] Next, the longitudinal position of the protrusion 17 will be described. Based on the thermal stress analysis described above, it is preferable to position the protrusion 17 at a location where the longitudinal distance L2 from the adhesive fixing portion 14 to the protrusion 17 is 10% or more of the longitudinal dimension L1 of the entire top surface 12. There is no particular restriction on the longitudinal distance between the protrusion 17 and the folded portion 16. However, if the protrusion 17 is too close to the folded portion 16, not only will the stress-shielding effect of the protrusion 17 be reduced, but interference with the folded portion 16, which typically has a complex three-dimensional shape, will become a problem. It is preferable to set the longitudinal position of the protrusion 17 taking these points into consideration. Note that the longitudinal distance L2 here refers to the smallest longitudinal distance between the adhesive fixing portion 14 and the protrusion 17 when viewed from the top surface 12 side.

[0022] In this case, the thickness distribution of the top surface portion 12 is arbitrary, and similarly, the thickness distribution of the folded portion 16 is also arbitrary. For example, the thickness dimension of the top surface portion 12 may be set to be uniform across its entire width. Similarly, the thickness dimension of the folded portion 16 may be set to be uniform across its entire width. In this embodiment, the top surface portion 12 and the folded portion 16 are all set to the same thickness dimension.

[0023] As described above, in the resin tailgate outer upper 10 according to this embodiment, the protrusion 17 extending in the width direction of the folded portion 16 (here, the width direction of the tailgate outer upper 10) is provided between the adhesive fixing portion 14 and the folded portion 16, both of which are provided on the non-design surface 13b side of the regulated area 13, where stretch along the surface is restricted by the adhesive fixing portion 14 with the tailgate inner member. The adhesive fixing portion 14 and the folded portion 16 are both provided on the peripheral edge of the regulated area 13 (here, the top surface 12). This configuration provides an area with high geometric rigidity between the adhesive fixing portion 14 and the folded portion 16, thereby preventing (blocking) as much as possible a situation in which the two stress concentration areas are connected across the central portion 13a of the regulated area 13. Furthermore, the provision of the protrusion 17, which is an area with high geometric rigidity, evens out the stress distribution throughout the regulated area 13, including the peripheral edge, thereby making it possible to alleviate stress concentration at each stress concentration area (the adhesive fixing portion 14, the folded portion 16). As described above, the resin tailgate outer upper 10 of this embodiment makes it possible to suppress the increase in thermal distortion in the central portion 13a of the restriction area 13, thereby preventing deformation of the restriction area 13 to a level that could result in poor appearance.

[0024] Although one embodiment of the present invention has been described above, the resin outer panel member according to the present invention can also have other configurations than those described above without departing from the spirit of the invention.

[0025] For example, in the above embodiment, the protrusions 17 extend linearly along the width direction of the folded-back portion 16, but the planar shape of the protrusions 17 (the shape viewed from the top surface portion 12) is not limited to this. For example, although not shown in the drawings, the planar shape of the protrusions 17 may be a shape in which both widthwise sides curve in either the front or rear direction as they move outward in the width direction.

[0026] Furthermore, in the above embodiment, the protrusion 17 is provided between the adhesive fixing portion 14 to the back door inner and the folded portion 16, but the application of the present invention is not limited to this. For example, although not shown, the back door outer upper 10 may be configured such that a portion fixed to the peripheral edge of the back door inner by a fixing means other than adhesion, such as welding, is provided on the peripheral edge of the restriction area 13, and the folded portion 16 is provided at a position sandwiching the fixed portion and the central portion 13a of the restriction area 13, and the protrusion 17 may be provided between the fixed portion and the folded portion 16.

[0027] Furthermore, although the above description has exemplified the case where the present invention is applied to the automobile back door outer upper 10, it is of course possible to apply the present invention to other panel parts. That is, the protrusion according to the present invention can be provided on any outer panel member, as long as the outer panel member forms the exterior of the vehicle together with the inner panel member and the fixed portion with the inner panel member and the folded portion are respectively provided at positions sandwiching the center of the restriction area. [Explanation of symbols]

[0028] 10 Back door outer upper 10a Periphery 11 Rear spoiler 12 Top section 12a Open side edge 13 Regulatory Area 13a central part 13b Non-design surface 14 Adhesive fixing part 15 Bending section 16 Folded section 17 Projection part L1 Front-to-rear dimension L2 Anteroposterior distance

Claims

1. A resin outer panel member that constitutes an exterior portion of a vehicle together with an inner panel member, a restriction region in which stretching along the surface is restricted while a portion of the peripheral edge portion is fixed to the inner panel member; a folded portion provided at a position sandwiching a portion of the peripheral edge of the restriction area that is fixed to the inner panel member and a central portion of the restriction area, the folded portion being folded back toward the central portion of the restriction area; A resin outer panel member having a protrusion extending in the width direction of the folded portion between the portion fixed to the inner panel member and the folded portion on the non-design surface side of the restriction area.

2. the resin outer panel member is a back door outer upper, and the restriction area is provided on a top surface portion of the back door outer upper, 2. The resin outer panel member according to claim 1, wherein a rear end portion of a rear spoiler is provided as the folded portion on the rear end side of the top surface portion.

3. 3. The resin outer panel member according to claim 2, wherein the protrusion portion is provided at a position where the distance from the peripheral edge of the regulating member to the portion fixed to the back door inner as the inner panel member is 10% or more of the longitudinal dimension of the entire top surface portion.

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