Vehicle exterior parts

Abstract

To provide a vehicle exterior part that can quickly reduce the electrostatic repulsion acting between the outer surface of the panel and the airflow. [Solution] The bumper cover 12 comprises a resin panel portion 13 that constitutes the outer shell of the vehicle, and a conductive coating 20 made of a conductive material that performs corona discharge in accordance with the potential of the static electricity charged on itself. A recess 16 is formed on the inner surface 13a of the panel portion 13. The conductive coating 20 is arranged to fill the recess 16.

Description

Technical Field

[0001] The present invention relates to exterior parts for vehicles.

Background Art

[0002] Patent Document 1 describes a vehicle in which a conductive film is provided inside a resin bumper cover. The conductive film is provided with sharp corners at its outer edge and outer peripheral wall so that corona discharge is likely to occur.

[0003] Here, generally, the surface of a vehicle is positively charged due to friction with an air flow or the like. In this case, since the air flow is also positively charged, an electrostatic repulsive force acts between the surface of the vehicle and the air flow. As a result, for example, there is a risk that the air flow peels off from the surface of the bumper cover. In this regard, according to the vehicle described above, corona discharge occurs at the corners of the conductive film, so that the charging of the bumper cover is suppressed and the above-mentioned electrostatic repulsive force is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to further improve the aerodynamic characteristics of a vehicle, in resin exterior parts for vehicles such as a bumper cover, it is desired to quickly reduce the electrostatic repulsive force acting between the surface and the air flow.

Means for Solving the Problems

[0006] Each aspect of an exterior part for a vehicle for solving the above problems is described. [Aspect 1] An exterior part for a vehicle comprising a resin panel that constitutes the outer shell of the vehicle, and a conductive coating made of a conductive material that performs corona discharge in accordance with the potential of the static electricity charged on itself, wherein a recess is formed on the inner surface of the panel, and the conductive coating is arranged to fill the recess.

[0007] According to the above configuration, since the conductive coating is arranged to fill the recesses formed on the inner surface of the panel, the distance between the conductive coating and the outer surface of the panel in the thickness direction is smaller compared to conventional vehicle exterior parts in which the conductive coating is simply laminated on the inner surface of the panel. Therefore, when positive static electricity is charged on the outer surface of the panel, the positive charge is more easily induced in the conductive coating. Then, in the conductive coating, corona discharge occurs in accordance with the potential of the charged positive static electricity, and the positive charge is neutralized using corona discharge. As a result, the potential of the outer surface of the panel can be efficiently reduced. Therefore, the electrostatic repulsion acting between the outer surface of the panel and the airflow can be rapidly reduced.

[0008] [Aspect 2] The vehicle exterior part according to [Aspect 1], wherein the conductive coating is a coating film comprising a base resin and a conductive filler dispersed in the base resin. According to the above configuration, since the conductive coating is composed of a coating film in which conductive fillers are dispersed in a base resin, the ends of the fillers tend to protrude outward from the end face of the base resin that mainly constitutes the inner surface of the conductive coating. Furthermore, positive charges concentrate at the ends of the fillers that are thus exposed to the outside, making it easier for corona discharge to occur at those ends. As a result, positive charges can be neutralized by corona discharge without providing sharp corners or pointed shapes on the conductive coating. Consequently, the potential of the outer surface of the panel can be reduced. Therefore, the electrostatic repulsion acting between the outer surface of the panel and the airflow can be reduced with a simple configuration.

[0009] [Aspect 3] The vehicle exterior part according to [Aspect 1] or [Aspect 2], wherein the recess is weight-shaped and tapers toward the outer surface of the panel in the thickness direction of the panel. According to the above configuration, the conductive coating filling the recess becomes cone-shaped, corresponding to the shape of the recess. In this case, the portion of the conductive coating closest to the outer surface of the panel in the thickness direction becomes the apex of the cone-shaped conductive coating. Therefore, compared to, for example, the above portion being composed of a surface, positive charges accumulated on the outer surface of the panel are more easily induced toward the apex. Furthermore, in the conductive coating, corona discharge occurs in response to the potential of the charged positive electrostatics, and the positive charges are neutralized using corona discharge. This allows the potential of the outer surface of the panel to be reduced more efficiently. Consequently, the electrostatic repulsion acting between the outer surface of the panel and the airflow can be reduced more quickly.

[0010] [Aspect 4] The vehicle exterior part according to [Aspect 3], wherein the interior angle of the portion of the cross-sectional shape including the vertex of the recess is acute. According to the above configuration, the interior angle of the portion of the cross-sectional shape including the vertex of the conductive coating that fills the recess is acute. In this case, compared to the case where the interior angle of the portion of the cross-sectional shape including the vertex is obtuse, positive charges are more easily induced from the outer surface of the panel to the conductive coating via the vertex. Then, in the conductive coating, corona discharge occurs in response to the potential of the charged positive electrostatics, and the positive charges are neutralized using corona discharge. As a result, the potential of the outer surface of the panel can be reduced more efficiently. Therefore, the electrostatic repulsion acting between the outer surface of the panel and the airflow can be reduced more quickly.

[0011] [Aspect 5] When the portion of the conductive coating that fills the recess is designated as the first portion, the conductive coating has a second portion that is laminated and bonded to the inner surface, and the first portion protrudes from the second portion to fill the recess, the vehicle exterior part according to any one of [Aspect 1] to [Aspect 4].

[0012] With the above configuration, the volume of the conductive coating increases by the amount of the second part compared to when the conductive coating is composed of only the first part. Consequently, the surface area of ​​the inner surface of the conductive coating exposed to the outside increases. Therefore, corona discharge and the neutralization of positive charges using corona discharge can be performed more efficiently on the inner surface. As a result, the potential of the outer surface of the panel can be reduced more efficiently. Consequently, the electrostatic repulsion acting between the outer surface of the panel and the airflow can be reduced more rapidly. [Effects of the Invention]

[0013] According to the present invention, the electrostatic repulsive force acting between the outer surface of the panel and the airflow can be quickly reduced. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a perspective view showing the front of a vehicle equipped with a bumper cover, which is one embodiment of a vehicle exterior part. [Figure 2] Figure 2 is a perspective view of the bumper cover shown in Figure 1, viewed from the opposite side. [Figure 3] Figure 3 is a cross-sectional view of the bumper cover shown in Figure 2, focusing on the recessed area and the conductive coating. [Figure 4] Figure 4 is a cross-sectional view showing an enlarged view of section X in Figure 3. [Figure 5] Figure 5 is a diagram illustrating the operation of this embodiment and is a cross-sectional view showing the bumper cover. [Figure 6] Figure 6 is a diagram illustrating the operation of this embodiment and is a cross-sectional view corresponding to Figure 3. [Figure 7] Figure 7 is a diagram illustrating the operation of this embodiment and is a cross-sectional view corresponding to Figure 4. [Figure 8] Figure 8 is a diagram showing an example of a modified conductive coating, and is a cross-sectional view corresponding to Figure 3. [Modes for carrying out the invention]

[0015] Hereinafter, referring to FIGS. 1 to 7, a bumper cover as an embodiment of a vehicle exterior component will be described. Hereinafter, the front and rear in the longitudinal direction of the vehicle 10 provided with the bumper cover 12 will be simply described as the front and the rear. Also, in the longitudinal and lateral directions of the vehicle 10, the side away from the central portion of the vehicle 10 will be referred to as the outside, outer side, etc., and the side approaching the central portion will be referred to as the inside, inner side, etc. for description.

[0016] <Bumper cover> As shown in FIG. 1, a bumper cover 12 is provided at the front portion 10A of the vehicle 10. The bumper cover 12 mainly constitutes the outer shell of the front portion 10A below a pair of headlamps 11.

[0017] As shown in FIGS. 1 to 3, the bumper cover 12 has a resin panel portion 13 and a conductive film 20. The panel portion 13 has a flat plate shape with a thickness in the longitudinal direction in its main part (hereinafter, the main body portion 14). That is, the thickness direction of the panel portion 13 in the main body portion 14 coincides with the longitudinal direction. Also, the panel portion 13 has a shape in which both end portions in the lateral direction (hereinafter, the side portions 15) are bent backward. The pair of side portions 15 have a thickness in the lateral direction. That is, the thickness direction of the panel portion 13 in both side portions 15 coincides with the lateral direction. The panel portion 13 has an outer surface 13b and an inner surface 13a opposite to the outer surface 13b in the thickness direction. Note that in this embodiment, the outer surface includes not only the surface that constitutes the design surface visible from the outside of the panel portion 13 but also the surface covered from the outside by exterior components such as the headlamp 11 adjacent to the bumper cover 12. The panel portion 13 is integrally formed of a resin material. Examples of the resin material include acrylonitrile-butadiene-styrene copolymer (ABS) resin.

[0018] As shown in FIGS. 2 and 3, a plurality of recesses 16 are formed on the inner surface 13a of the panel portion 13. In the present embodiment, the plurality of recesses 16 are arranged at intervals over the entire inner surface 13a. The shape of the recess 16 is conical. Specifically, the shape of the recess 16 is a right circular cone in which an axis L extending along the axis of the recess 16 extends perpendicular to the opening surface 16a of the recess 16. For this reason, the bottom portion 16b located at the apex position of the cone among the recesses 16 has a smaller distance from the outer surface 13b than other portions in the thickness direction of the panel portion 13. In the present embodiment, the bottom portion 16b is located closer to the outer surface 13b than the central portion of the panel portion 13 in the thickness direction of the panel portion 13.

[0019] As shown in FIG. 3, the cross-sectional shape including the bottom portion 16b of the recess 16 is triangular. In FIG. 3, the cross-sectional shape along a virtual plane including the axis L of the recess 16 is shown, and the shape is an isosceles triangle. The recess 16 is set such that the inner angle θ of the portion including the bottom portion 16b in the cross-sectional shape is an acute angle.

[0020] <Conductive film> As shown in Figures 3 and 4, the conductive coating 20 is positioned to fill the recess 16. The conductive coating 20 is in close contact with the inner surface 16c of the recess 16. The conductive coating 20 has a conical shape that is generally congruent to the shape of the recess 16. The conductive coating 20 is composed of a coating film containing a base resin 21 and a conductive filler 22 dispersed in the base resin 21 (see Figure 4). The conductive coating 20 is formed by applying a coating containing the base resin 21 and the filler 22 into the recess 16. Examples of the base resin 21 include resin materials included in known resin coatings such as acrylic resins, urethane resins, polyester resins, epoxy resins, melamine resins, alkyd resins, and phenolic resins. The filler 22 is a conductive filler that imparts conductivity to the base resin 21. Examples of such conductive fillers include metal-based fillers such as aluminum flakes, metal oxide-based fillers such as zinc oxide, metal-coated fillers in which the surface of mica or glass flakes is coated with a metal such as aluminum or nickel, or carbon-based fillers such as carbon black. In particular, it is preferable to use carbon-based nanofillers such as carbon nanotubes (CNTs) or carbon nanofibers (CNFs) to induce corona discharge. In this embodiment, filler 22 is a CNT.

[0021] As shown in Figure 4, on the inner surface 20a of the conductive coating 20, the ends 22a of multiple fillers 22 protrude outward (inward in the front-rear direction and vehicle width direction) from the end face 21a of the base resin 21. The multiple ends 22a are exposed in the space S between the vehicle frame member (not shown) of the vehicle 10, which is located inward from the bumper cover 12, and the bumper cover 12.

[0022] <Operation of this embodiment> The operation of this embodiment will be explained with reference to Figure 1 and Figures 5 to 7. As shown in Figures 1 and 5, the outer surface 13b of the panel 13 becomes charged due to various factors while the vehicle 10 is in motion. For example, when the airflow A flowing from front to rear flows along the outer surface 13b, friction occurs between it and the outer surface 13b, or the outer surface of the tire 17 repeatedly contacts and separates from the road surface, causing positive static electricity to build up on the outer surface 13b. In this case, the airflow A flowing along the outer surface 13b flows away from the outer surface 13b due to the electrostatic repulsion acting between it and the outer surface 13b, as shown by the dashed line in Figure 1. In other words, separation of the airflow A from the outer surface 13b occurs.

[0023] In this embodiment, the bumper cover 12 has a plurality of recesses 16 formed on the inner surface 13a of the panel portion 13. Furthermore, a conductive coating 20 is placed in each of the formed recesses 16 so as to fill the recess 16. As a result, compared to conventional vehicle exterior parts in which a conductive coating is simply laminated on the inner surface 13a of the panel portion 13, the distance between the conductive coating 20 and the outer surface 13b in the thickness direction (vertical direction in Figure 5) of the panel portion 13 is reduced. In particular, since the conductive coating 20 in this embodiment is conical in shape corresponding to the shape of the recesses 16, a positive charge 30 is further induced at the tip portion 20b of the conductive coating 20 that is closest to the outer surface 13b in the thickness direction of the panel portion 13.

[0024] As shown in Figures 6 and 7, the positive charge 30 accumulated at the tip 20b of the conductive coating 20 moves towards the inner surface 20a, which has a lower potential than the tip 20b, via the conductive filler 22 dispersed in the base resin 21. When the positive charge 30 concentrates at the end 22a of the filler 22 that protrudes outward from the end face 21a (see Figure 7), the potential at this end 22a increases and the electric field strengthens, causing corona discharge. In addition, the positive charge 30 is neutralized using corona discharge. As a result, the potential on the inner surface 20a of the conductive coating 20 is always kept lower than that on the tip 20b side. Consequently, the flow of positive charge 30 from the tip 20b side to the inner surface 20a side is maintained. In this way, the positive charge 30 accumulated on the outer surface 13b is efficiently discharged. That is, the potential of the outer surface 13b is efficiently reduced.

[0025] <Effects of this embodiment> (1) The bumper cover 12 comprises a resin panel portion 13 that constitutes the outer shell of the vehicle 10, and a conductive coating 20 made of a conductive material that performs corona discharge in accordance with the potential of the static electricity charged on itself. A recess 16 is formed on the inner surface 13a of the panel portion 13. The conductive coating 20 is positioned to fill the recess 16.

[0026] This configuration produces the effects described above. Therefore, the electrostatic repulsion acting between the outer surface 13b of the panel 13 and the airflow A can be quickly reduced. (2) The conductive coating 20 is a coating film comprising a base resin 21 and a conductive filler 22 dispersed in the base resin 21.

[0027] With this configuration, since the conductive coating 20 is composed of a coating film in which conductive filler 22 is dispersed in the base resin 21, the ends 22a of the filler 22 tend to protrude outward from the end face 21a of the base resin 21. Furthermore, positive charges 30 concentrate at the ends 22a of the filler 22 exposed to the space S, making it easier for corona discharge to occur at these ends 22a. This allows for the neutralization of positive charges 30 by corona discharge without providing the conductive coating 20 with sharp corners or other pointed shapes. Consequently, the potential of the outer surface 13b of the panel portion 13 can be reduced. Therefore, with a simple configuration, the electrostatic repulsion acting between the outer surface 13b of the panel portion 13 and the airflow A can be reduced.

[0028] (3) The recess 16 is cone-shaped. With this configuration, the conductive coating 20 filling the recess 16 becomes conical in shape, corresponding to the shape of the recess 16. In this case, the part of the conductive coating 20 closest to the outer surface 13b of the panel 13 in the thickness direction of the panel 13 becomes the tip 20b, which forms the apex of the conical conductive coating 20 (see Figure 3). Therefore, compared to the case where the above part is made up of a surface, for example, the positive charge 30 accumulated on the outer surface 13b of the panel 13 is more easily induced toward the tip 20b. Furthermore, in the conductive coating 20, corona discharge occurs in accordance with the potential of the charged positive electrostatic, and the positive charge 30 is neutralized using corona discharge. This makes it possible to lower the potential of the outer surface 13b of the panel 13 more efficiently. Consequently, the electrostatic repulsion acting between the outer surface 13b of the panel 13 and the airflow A can be reduced more quickly.

[0029] (4) The interior angle θ of the portion of the cross-sectional shape including the bottom 16b at the apex of the recess 16 is acute. With this configuration, the interior angle θ of the portion of the cross-sectional shape including the tip 20b, which is the apex of the conductive coating 20 filling the recess 16, becomes acute. In this case, compared to the case where the interior angle θ of the portion of the cross-sectional shape including the tip 20b is obtuse, positive charges 30 are more easily induced from the outer surface 13b of the panel portion 13 to the conductive coating 20 via the tip 20b. Then, in the conductive coating 20, corona discharge occurs in response to the potential of the charged positive electrostatics, and the positive charges 30 are neutralized using corona discharge. As a result, the potential of the outer surface 13b of the panel portion 13 can be reduced more efficiently. Therefore, the electrostatic repulsion acting between the outer surface 13b of the panel portion 13 and the airflow A can be reduced more quickly.

[0030] <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0031] The conductive coating according to the present invention is not limited to the conductive coating 20 shown in this embodiment, but can also be embodied as, for example, the conductive coating 120 shown in Figure 8. That is, as shown in Figure 8, the conductive coating 120 has a second portion 122 that is laminated and bonded to the inner surface 13a, and a first portion 121 that protrudes outward from the second portion 122 and fills the recess 16. The first portion 121 corresponds to the conductive coating 20 in this embodiment.

[0032] With this configuration, the volume of the conductive coating 120 increases by the amount of the second portion 122 compared to the conductive coating 20 in which the conductive coating 120 is composed only of the first portion 121. Consequently, the surface area of ​​the inner surface 120a of the conductive coating 120 that is exposed to the outside increases. Therefore, corona discharge and the neutralization of positive charges 30 using corona discharge can be performed more efficiently on the inner surface 120a. As a result, the potential of the outer surface 13b of the panel portion 13 can be reduced more efficiently. Consequently, the electrostatic repulsion acting between the outer surface 13b of the panel portion 13 and the airflow A can be reduced more quickly.

[0033] The recess 16 may be configured such that the interior angle θ of the portion of its cross-sectional shape that includes the bottom portion 16b is obtuse. In this case, the interior angle θ of the portion of the cross-sectional shape that includes the tip portion 20b of the conductive coating 20 is also obtuse.

[0034] The shape of the conductive coating 20 is not limited to a cone shape where the tip portion 20b is composed of points, but the tip portion 20b may be a rounded cone shape. In this case, the shape of the recess 16 should also be such that the bottom portion 16b is a rounded cone shape.

[0035] The shape of the conductive coating 20 is not limited to a conical shape with a circular inner surface 20a; the inner surface 20a may be a polygonal pyramidal shape, or a truncated shape with a flat tip 20b. Furthermore, the shape of the conductive coating 20 is not limited to a conical shape that tapers towards the outer surface 13b; the shape may be changed as appropriate within the range that achieves the effects of the present invention. For example, the shape of the conductive coating 20 can be semicircular or rectangular parallelepiped. In these cases, the shape of the recess 16 can be appropriately changed so that the shape of the conductive coating 20 becomes the desired shape.

[0036] The conductive coating according to the present invention is not limited to a coating in which a conductive filler 22 is dispersed in a base resin 21, but can be appropriately modified as long as it is made of a conductive material and performs corona discharge in accordance with the potential of the static electricity charged on itself. Examples of such conductive coatings include a conductive adhesive tape consisting of a layer of metal foil such as aluminum and an adhesive, and a plated layer obtained by plating the inner surface 16c of a recess 16.

[0037] The arrangement of the recesses 16 and conductive coatings 20 is not limited to being provided across the entire inner surface 13a, as illustrated in this embodiment. The arrangement can be appropriately changed as long as they are provided on the inner surface 13a. For example, the recesses 16 and conductive coatings 20 may be provided only in the areas of the inner surface 13a corresponding to the main body 14, or only in the areas corresponding to the pair of side parts 15. Alternatively, the recesses 16 and conductive coatings 20 may be provided on the outer surface 13b opposite to specific areas where positive charges 30 tend to accumulate.

[0038] The recess 16 and the conductive coating 20 may, for example, be placed only on the opposite side of the design surface of the bumper cover 12, or only on the opposite side of the bumper cover 12 that is covered from the outside by exterior parts such as the headlamp 11 adjacent to the bumper cover 12.

[0039] The vehicle exterior parts according to the present invention are not limited to the bumper cover 12 exemplified in this embodiment, but can also be embodied as other vehicle exterior parts that constitute the outer shell of the front 10A. Furthermore, the vehicle exterior parts according to the present invention are not limited to vehicle exterior parts that constitute the outer shell of the front 10A, but can also be embodied as exterior parts such as fenders that constitute the outer shell of the side of the vehicle 10, or exterior parts such as a rear bumper cover that constitutes the outer shell of the rear of the vehicle 10, as long as they are made of resin. [Explanation of symbols]

[0040] θ... interior angle A...Airflow L…axis S…Space 10... Vehicles 10A…Front 11… Headlights 12... Bumper cover 13... Panel section 13a...Inner self 13b...Outer surface 14…Main body 15... Side 16…recess 16a...Opening surface 16b…bottom 16c...inner 17... Tires 20,120…Conductive coating 20a, 120a…inner surface 20b…Tip 21…Base resin 21a...end face 22… Filler 22a...end 30…Charge 121…Part 1 122…Second part

Claims

1. The resin panel section that makes up the outer shell of the vehicle, It comprises a conductive coating made of a conductive material that undergoes corona discharge in response to the potential of the electrostatic charge it has accumulated on itself, A recess is formed on the inner surface of the panel portion. The conductive coating is arranged to fill the recess. Vehicle exterior parts.

2. The conductive coating is a coating film comprising a base resin and a conductive filler dispersed in the base resin. Vehicle exterior part according to claim 1.

3. The recess is cone-shaped, tapering toward the outer surface of the panel in the thickness direction of the panel. Vehicle exterior part according to claim 1 or claim 2.

4. The interior angle of the portion of the cross-sectional shape including the vertex of the recess is acute. Vehicle exterior part according to claim 3.

5. When the portion of the conductive coating that fills the recess is defined as the first portion, The conductive coating has a second portion which is laminated and bonded to the inner surface. The first portion protrudes from the second portion and fills the recess. Vehicle exterior part according to claim 1 or claim 2.

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