Vehicle back door

Abstract

Creep deformation of the rear spoiler can be suppressed. [Solution] The vehicle tailgate is equipped with a rear spoiler having an inner panel and an outer panel made of thermoplastic resin that is arranged outside the inner panel with an internal space between them, and that has a deformation suppression area with a plate thickness set to 3 mm or more and 4.75 mm or less.

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle back door. [Background technology]

[0002] Conventionally, a vehicle back door that is attached to the rear of a vehicle body in an openable and closable manner has been known, as shown in Patent Document 1. The vehicle back door of Patent Document 1 includes an inner panel having an opening that forms a window, an outer panel made of thermoplastic resin that is arranged on the outside of the inner panel so as to close the opening, and a rear spoiler attached to an upper part of the outer panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-25996 Summary of the Invention [Problem to be solved by the invention]

[0004] Rear spoilers for vehicle tailgates can not only be deformed by short-term loads such as collisions, but can also be subject to creep deformation, which is a gradual long-term deformation that occurs over time. Creep deformation is mainly caused by the application of weak stress due to the vehicle's own weight at high temperatures.

[0005] One possible way to suppress deformation of a component is to increase its rigidity by increasing its thickness. Improving the rigidity of a component is effective in suppressing deformation of the component due to short-term loads such as a collision. However, simply increasing the thickness of the component also increases the weight of the rear spoiler, so it is necessary to consider the effect of increased weight on creep deformation.

[0006] In this regard, no consideration is given to creep deformation of the rear spoiler in Patent Document 1. Therefore, even if the plate thickness of the rear spoiler in Patent Document 1 is simply increased, there is a problem in that it is difficult to suppress creep deformation because the effect of increased weight on creep deformation is not considered.

[0007] The present disclosure has been made in light of the above, and provides a technique that can suppress creep deformation of a rear spoiler. [Means for solving the problem]

[0008] Specific means for achieving the above objectives are as follows: <1> A rear spoiler comprising: an inner panel; and an outer panel made of thermoplastic resin and arranged outside the inner panel with an internal space therebetween, the outer panel having a deformation suppression region with a plate thickness set to 3 mm or more and 4.75 mm or less. A vehicle back door comprising: [Effects of the Invention]

[0009] According to the present disclosure, creep deformation of the rear spoiler can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view illustrating a configuration of a vehicle back door according to an embodiment of the present disclosure. FIG. [Figure 2] 1 is a plan view illustrating a configuration of a vehicle back door according to an embodiment of the present invention. FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] 10A and 10B are diagrams illustrating the amount of deformation of an upper outer panel due to creep deformation. [Figure 5] 10 is a graph illustrating the amount of deformation of an upper outer panel due to creep deformation, with the plate thickness being changed. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described below. However, the present disclosure is not limited to the following embodiments. When embodiments are described with reference to drawings in the present disclosure, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of components in each drawing are conceptual, and the relative size relationships between components are not limited to these.

[0012] In the following description of the drawings, like parts are designated by like reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions, and the thickness ratio of each device and each component, differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined by taking into consideration the following explanation. Furthermore, there are parts in which the dimensional relationships and ratios differ between the drawings. Furthermore, unless otherwise specified in the specification, the number of each component element of the present disclosure is not limited to one, and there may be multiple elements.

[0013] In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and they do not limit the present disclosure. In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0014] In the present disclosure, when components are contained, each component may contain multiple types of corresponding substances. When multiple types of substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In the present disclosure, the particles corresponding to each component may contain multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, the terms "layer" and "film" include cases where the layer or film is formed over the entire area when the area in which the layer or film is present is observed, as well as cases where the layer or film is formed over only a portion of the area.

[0015] <Vehicle back door> A vehicle back door 10 according to this embodiment will be described with reference to Figures 1 to 5. Figure 1 illustrates a front side FR and a rear side RR in the longitudinal direction of the vehicle, a left side LH and a right side RH in the lateral direction, and an upper side UR and a lower side LR in the vertical direction.

[0016] 1, a vehicle back door 10 of this embodiment mainly includes a resin inner panel 12, a resin upper outer panel 14, a resin lower outer panel 16, and a window glass 18. The vehicle back door of this embodiment also includes a rear spoiler 11.

[0017] The vehicle back door 10 may be provided with a main reinforcement, a hinge mounting reinforcement, a damper mounting reinforcement, a lock member mounting reinforcement, a lock member as an example of a door lock device, a wiper motor as an example of a functional part, etc. The window glass 18 is adhered to the opening 12A of the inner panel 12 using an adhesive (not shown).

[0018] Hinge mounting reinforcements (not shown) made of metal plates or the like are connected to the upper edge portion of the inner panel 12 on both the left and right sides with connecting members (not shown) such as bolts and nuts. A hinge 19 that connects the vehicle back door 10 to the vehicle body 20 is attached to the hinge mounting reinforcements.

[0019] 1 and 3, an upper outer panel 14 is joined to the inner panel 12 at an upper portion of the window glass 18 with joining members (not shown) such as bolts and nuts. A sealing component (not shown) is interposed between the outer peripheral edge of the upper outer panel 14 and the inner panel 12. The sealing component seals the gap between the outer peripheral edge of the upper outer panel 14 and the inner panel 12.

[0020] The sealing parts are formed of foam rubber, for example. The sealing parts are attached to the inner panel 12 using adhesive tape. The sealing parts also include double-sided tape and the like. Any material can be used for the sealing parts. The sealing parts may be attached to the upper outer panel side instead of the inner panel 12. When sealing between the hinge 19 mounting reinforcement and the upper outer panel 14, the sealing parts may be attached to the hinge 19 mounting reinforcement. The vehicle back door 10 is attached to the vehicle body (vehicle body 20 in FIG. 2) by the two upper hinges 19 and one locking portion (not shown) provided on the lower outer panel 16.

[0021] (rear spoiler) 1, the rear spoiler 11 is an overall rectangular plate-like or box-like member in a plan view. The rear spoiler 11 includes an inner panel 12 and an upper outer panel 14 that is disposed outside the inner panel 12 with an internal space between them. The outer frame portions of the inner panel 12 and the upper outer panel 14 of the rear spoiler 11 are joined together with an adhesive.

[0022] In this embodiment, the inner panel 12 and the upper outer panel 14 that constitute the rear spoiler 11 are both made of a thermoplastic resin such as polypropylene. In the present disclosure, it is sufficient that at least the upper outer panel that constitutes the rear spoiler is made of a thermoplastic resin.

[0023] 2, the upper outer panel 14 constituting the rear spoiler 11 has a top portion 14A extending in the left-right direction and a pair of side portions 14B provided at each end of the top portion 14A in the left-right direction. In this embodiment, the top portion 14A and the pair of side portions 14B are integrally molded, but in the present disclosure, the top portion and the pair of side portions may be manufactured separately.

[0024] As shown in Figure 2, the top portion 14A is rectangular. The main surface of the top portion 14A extends approximately horizontally. Each of the pair of side portions 14B is bent at the boundary with the top portion 14A so as to face the corresponding side portion of the vehicle body 20. When the vehicle back door 10 is attached to the vehicle body 20 by two upper hinges 19 and one lower lock portion (not shown), the upper outer panel 14 has a maximum length L of the top portion 14A measured along the front-rear direction and a maximum width W of the top portion 14A measured along the left-right direction.

[0025] (deformation suppression area) As shown in Fig. 3, creep deformation occurs in the upper outer panel 14 mainly due to its own weight. To suppress creep deformation, the upper outer panel 14 constituting the rear spoiler 11 of this embodiment has a deformation suppression region X in which the plate thickness is set to 3 mm or more and 4.75 mm or less. The plate thickness set within the deformation suppression region X may be the same or different.

[0026] The deformation suppression region X of this embodiment is formed over the entire upper outer panel 14 in the left-right direction and the entire upper outer panel 14 in the front-rear direction in a plan view. The deformation suppression region of the present disclosure may be formed in a portion of the upper outer panel. Also, in the present disclosure, a plurality of partially formed deformation suppression regions may be provided. For example, the deformation suppression region may be formed only in the center portion in the left-right direction, or may be formed over the entire left-right direction. Also, the deformation suppression region may be formed only in the center portion in the front-rear direction, or may be formed over the entire front-rear direction. [Example]

[0027] Next, the deformation suppression region X of this embodiment will be specifically described using an example. In the example, in order to confirm the relationship between the thickness of the top portion 14A of the upper outer panel 14 and creep deformation, creep deformation was reproduced using the strain hardening law. In the strain hardening law, creep hardening is governed by creep strain generated after stress loading. The creep strain (ε c ) is given by the following equation (1):

[0028]

number

[0029] The creep strain rate is calculated by multiplying the creep strain (ε c ) is given by the time derivative of

number

[0030] 3, at the top 14A of the upper outer panel 14 located on the rear end side of the rear spoiler, an internal space 15 is formed between the upper outer panel 14 and the lower inner panel 12. No support structure such as a wall is provided to connect the upper outer panel 14 and the lower inner panel 12. For this reason, creep deformation is likely to occur in the area that overlaps with the internal space 15 in a plan view.

[0031] As shown in Figure 4, in this example, analytical model 14P of the top portion corresponding to top portion 14A was created using commercially available FEM analysis software "Abaqus" as an example of an analysis program. In the analysis, the amount of creep deformation that occurs when analytical model 14P of the top portion, which has a plate thickness of 1.50 mm, is maintained at 90°C for 60 hours is analyzed over the entire top surface of the top portion.

[0032] In the analytical model 14P at the top in Fig. 4, the darker the part, the larger the amount of deformation that occurred. In this example, the amount of deformation was large in the region below the center in the left-right direction in Fig. 4 (the rear side of the vehicle) and in the regions on each end side in the left-right direction in Fig. 4 (the left and right side portions 14B side of the vehicle).

[0033] The present inventors also calculated the deformation amount (i.e., maximum deformation amount) of the most deformed portion within the analysis area of ​​the analytical model 14P of the top having a plate thickness of 1.50 mm. Analytical models of tops having plate thicknesses other than 1.50 mm were similarly created, and the deformation amount of the most deformed portion within the analysis area of ​​each analytical model was calculated. In Table 1 below, the deformation amount of the most deformed portion of the analytical model of the top having each plate thickness is represented as "deformation amount." The plate thickness and deformation amount of each analytical model in Table 1 are also plotted in Figure 5.

[0034] [Table 1]

[0035] As shown in Table 1 and Figure 5, when the plate thickness was 3.00 mm or more, the amount of deformation was suppressed to 0.3213 mm or less. Furthermore, when the plate thickness was 4.75 mm, the lowest amount of deformation of 0.2830 mm was obtained among all the analysis models. When the plate thickness exceeded 4.75 mm, the amount of deformation could be suppressed to 0.3 mm or less, but the amount of deformation suppression (i.e., the difference) relative to the amount of deformation for a plate thickness of 1.5 mm slowed down. This is thought to be because the creep deformation caused by the plate's own weight increased as the plate thickness increased.

[0036] (Action and effect) In the vehicle back door according to this embodiment, the upper outer panel 14 of the rear spoiler 11 has a deformation suppression region with a plate thickness set to 3 mm or more and 4.75 mm or less. If the plate thickness is less than 3 mm, the creep deformation suppression effect obtained is small. On the other hand, if the plate thickness exceeds 4.75 mm, the influence of the weight of the upper outer panel 14 becomes large, and as a result, the creep deformation suppression effect obtained is small.

[0037] In this embodiment, the plate thickness is set within a range of 3 mm to 4.75 mm, taking into consideration the balance between the obtained effect of suppressing creep deformation and the influence of weight increase. In this embodiment, by setting the plate thickness within a range of 3 mm to 4.75 mm without changing the appearance of the upper outer panel 14, the amount of creep deformation of the upper outer panel 14 is reduced. Therefore, it is possible to suppress creep deformation while suppressing changes in the appearance of the rear spoiler 11.

[0038] <Other embodiments> Although the present disclosure has been described by the above disclosed embodiments, the descriptions and drawings that form part of this disclosure should not be understood to limit the present disclosure. The present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined by the invention-specific matters in the scope of the claims that are appropriate from the above description. [Explanation of symbols]

[0039] 10. Vehicle back door 11 Rear spoiler 12 Inner panel 12A opening 14 Upper outer panel (outer panel) 14A Top 14B Side 14P Top Analysis Model 15 Interior Space 16 Lower outer panel 18 Window Glass 19 Hinge 20 Body H Plate thickness setting range L Maximum length of top of upper outer panel W Maximum width at top of upper outer panel X Deformation suppression area FR front side RR front side LH Left side RH Right side UR upper side LR lower side

Claims

[Claim 1] A rear spoiler comprising: an inner panel; and an outer panel made of a thermoplastic resin and arranged outside the inner panel with an internal space therebetween, the outer panel having a deformation suppression region with a plate thickness set to 3 mm or more and 4.75 mm or less. A vehicle back door comprising:

Images