Vehicular panel structure

A vehicular panel structure includes an inner panel disposed on an inner side of a vehicle; an outer panel disposed on an outer side of the inner panel in the vehicle, having a linear expansion coefficient different from a linear expansion coefficient of the inner panel, and having an adhesive surface joined by an adhesive to an adhesive surface of the inner panel; and an affixed member affixed to a part of the adhesive surface of the outer panel. The affixed member is configured to adhere less to the adhesive than to the adhesive surface of the inner panel or the adhesive surface of the outer panel to which the affixed member is affixed.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2017-003290 filed on Jan. 12, 2017 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates to a vehicular panel structure.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2014-083904 (JP 2014-083904 A) discloses a structure in which a one-side adhesive portion adhering to either an inner panel or an outer panel is disposed by a part of the inner panel or the outer panel not being subjected to a primer treatment in a vehicular panel member in which the inner panel and the outer panel with different linear expansion coefficients are joined to each other by an adhesive. In the configuration described above, the thermal distortion of the panels is further suppressed by the disposition of the one-side adhesive portion adhering to either the inner panel or the outer panel. Japanese Unexamined Utility Model Application Publication No. 01-057971 (JP 01-057971 U) discloses a vehicular panel structure in which an elastic member is interposed between an inner panel and an outer panel, an adhesive portion is provided on one side surface of the elastic member, and the adhesive portion adheres to at least one of the inner panel and the outer panel.

SUMMARY

In the vehicular panel member that is disclosed in JP 2014-083904 A, the positional variation of the one-side adhesive portion may increase in a case where the one-side adhesive portion is disposed by a part of the inner panel or the outer panel not being subjected to a primer treatment.

The disclosure provides a vehicular panel structure with which the positional variation of a non-adhesive portion can be appropriately suppressed and the panel distortion that is attributable to a difference in a linear expansion coefficient can be effectively suppressed.

An aspect of the disclosure relates to a vehicular panel structure including an inner panel disposed on an inner side of a vehicle, an outer panel disposed on an outer side of the inner panel, and an affixed member. The outer panel has a linear expansion coefficient different from a linear expansion coefficient of the inner panel, and has an adhesive surface joined by an adhesive to an adhesive surface of the inner panel. The affixed member is affixed to a part of the adhesive surface of the inner panel or the adhesive surface of the outer panel. The affixed member is configured to adhere less to the adhesive than to the adhesive surface of the inner panel or the adhesive surface of the outer panel to which the affixed member is affixed.

According to the aspect of the disclosure, the linear expansion coefficient of the outer panel differs from the linear expansion coefficient of the inner panel and the adhesive surface of the outer panel is joined to the adhesive surface of the inner panel by the adhesive. The affixed member is affixed to a part of the adhesive surface of the inner panel or the adhesive surface of the outer panel. The affixed member adheres less to the adhesive than to the adhesive surface of the inner panel or the adhesive surface of the outer panel to which the affixed member is affixed. In the configuration described above, the affixed member is affixed to a part of the adhesive surface of the inner panel or the adhesive surface of the outer panel and the affixed member has a relatively low level of adhesiveness with the adhesive. As a result, in the region to which the affixed member is affixed, a state occurs where the inner panel or the outer panel is not bound by the adhesive. In other words, a state of almost no adhesion (non-adhesive portion) occurs in the region. Accordingly, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel and the outer panel can be effectively avoided. In addition, the dimension of the affixed member and the position to which the affixed member is affixed can be adjusted with ease, and thus positional variations can be reduced compared to, for example, a configuration in which a one-side adhesive portion is disposed as a result of a primer treatment.

In the vehicular panel structure according to the aspect of the disclosure, the adhesive may cause an outer edge of the inner panel and an outer edge of the outer panel to adhere to each other, and the affixed member may be disposed at a part of the outer edge of the inner panel or the outer edge of the outer panel.

According to the aspect of the disclosure, the outer edge of the inner panel and the outer edge of the outer panel are caused to adhere to each other by the adhesive. Accordingly, adhesiveness is ensured between the inner panel and the outer panel. In addition, by the affixed member being disposed at a part of the outer edge of the inner panel or the outer edge of the outer panel, a state (state of almost no adhesion) occurs where a part of the outer edge of the inner panel or the outer edge of the outer panel is not bound by the adhesive. As a result, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel and the outer panel can be more effectively avoided with adhesiveness ensured between the inner panel and the outer panel.

In the vehicular panel structure according to the aspect of the disclosure, a stepped portion may be disposed on at least a part of the inner panel and the outer panel, and the affixed member may be disposed adjacent to the stepped portion.

According to the aspect of the disclosure, the stepped portion is disposed on at least a part of the outer panel and the inner panel and the affixed member is disposed adjacent to the stepped portion. Although stress concentration, and distortion in particular, are likely to occur in the vicinity of the stepped portion of the outer panel or the inner panel, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel and the outer panel can be more effectively avoided as the affixed member is disposed adjacent to the stepped portion.

In the vehicular panel structure according to the aspect of the disclosure, the inner panel and the outer panel may constitute a door of the vehicle, and the affixed member may be disposed in a lower end portion of the door in an up-down direction of the vehicle.

According to the aspect of the disclosure, the inner panel and the outer panel constitute the door of the vehicle. In the region of the outer panel or the inner panel to which the affixed member is affixed, a state (state of almost no adhesion) occurs where either the outer panel or the inner panel is not bound by the adhesive while the adhesive is in close contact with the outer panel or the inner panel. The affixed member is disposed in the lower end portion of the door in the up-down direction of the vehicle, and thus the dew condensation water generated in the door can be discharged by oozing out between the affixed member and the adhesive and dust and sound movements into the cabin of the vehicle can be further suppressed.

In the vehicular panel structure according to the aspect of the disclosure, the affixed member may be affixed to the outer panel side, the outer panel side being a design surface side.

According to the aspect of the disclosure, the affixed member is affixed to the outer panel side, the outer panel side being a design surface side, and distortion of the outer panel as a design surface can be more effectively avoided.

In the vehicular panel structure according to the aspect of the disclosure, the affixed member may be configured of a plastic film.

In the vehicular panel structure according to the aspect of the disclosure, the affixed member may be a resin-molded article and may be provided with a plurality of planar joined portions and a plurality of recessed portions molded in an intermediate portion of the planar joined portions.

In the vehicular panel structure according to the aspect of the disclosure, the joined portions of the affixed member may be joined to the adhesive surface of the outer panel at a position of a rear side vertical wall portion of the outer panel adjacent to a stepped portion such that recessed parts of the recessed portions pass along an up-down direction of the vehicle.

With the vehicular panel structure according to the aspect of the disclosure, the positional variation of the non-adhesive portion can be appropriately suppressed and the panel distortion that is attributable to the difference in the linear expansion coefficient can be effectively suppressed.

DETAILED DESCRIPTION OF EMBODIMENTS

A vehicular panel structure according to embodiments of the disclosure will be described with reference to accompanying drawings. The arrows FR, UP, RH, and LH that are appropriately shown in each of the drawings represent the forward direction, the upward direction, the rightward direction, and the leftward direction of a vehicle to which the vehicular panel structure according to the embodiments of the disclosure is applied, respectively. The rightward and leftward directions are directions with respect to the forward direction. Unless otherwise noted, the front-rear, up-down, and right-left directions mentioned in the following description represent the front-rear direction in the front-rear direction of the vehicle, the up-down direction in the up-down direction of the vehicle, and the right-left direction in the right-left direction of the vehicle (width direction of the vehicle) with respect to the forward direction, respectively.

First Embodiment

Hereinafter, a back door to which a vehicular panel structure according to a first embodiment is applied will be described with reference toFIGS. 1 to 8.

A vehicle10is illustrated inFIG. 1. The vehicle10is configured to include a vehicle body12and a back door16as an example of the doors of the vehicle. As illustrated inFIG. 1, a door opening portion14open in the front-rear direction of the vehicle is formed at the rear end of the vehicle body12. In the vehicle body12, a door hinge18(refer toFIG. 2) is disposed in the upper edge portion of the door opening portion14and an upper edge portion32D (refer toFIG. 2) of an inner panel32(described later). The door hinge18supports the back door16such that the back door16is capable of rotating about its axis direction in the width direction of the vehicle.

The back door16is capable of opening and closing the door opening portion14by rotating about the door hinge18(refer toFIG. 2).FIG. 1shows a closed position, at which the door opening portion14is closed by the back door16.FIG. 2shows an open position, at which the back door16is open with respect to the door opening portion14.

As illustrated inFIG. 2, the back door16is formed in a substantially L-shape in side view of the vehicle. In a state where the back door16is disposed at the closed position, the upper and rear parts of the door opening portion14are closed by the back door16. As illustrated inFIG. 1, the back door16is provided with a door upper portion16A and a door lower portion16B. The door upper portion16A gently and obliquely extends rearward and downward from an upper end portion in the up-down direction of the vehicle and the door lower portion16B drops downward from the rear end portion of the door upper portion16A in the front-rear direction of the vehicle (refer toFIG. 1). The disposition of each of the portions that constitute the back door16will be described on the assumption that the back door16is disposed at the closed position.

As illustrated inFIGS. 1 and 2, the back door16is configured to include a back door body22, a rear window24disposed on the upper portion side of the back door16, a rear spoiler26disposed on the rear side of the rear window24, and a lower window28for a small window disposed on the lower side of the rear spoiler26. The rear window24is disposed in the door upper portion16A and the lower window28is disposed in the upper portion of the door lower portion16B. The rear spoiler26is disposed between the rear window24and the lower window28.

A vehicular panel structure S20(refer toFIG. 4and so on) according to the first embodiment is applied to the back door16as illustrated inFIG. 3. The back door body22is provided with the inner panel32and an outer panel34. The inner panel32constitutes a part of the back door16and is disposed on the inner side of the vehicle. The outer panel34constitutes a part of the back door16and is disposed on an outer side of the vehicle. The back door body22is also provided with an extension36disposed between the inner panel32and the outer panel34.

The inner panel32is a panel member that constitutes a main part of the back door body22. The inner panel32is formed in a substantially L-shape in side view of the vehicle. The inner panel32is provided with an upper portion32A disposed in the door upper portion16A (refer toFIGS. 1 and 2) and a lower portion32B disposed in the door lower portion16B (refer toFIGS. 1 and 2). The inner panel32is provided with an upper side opening portion38formed in the upper portion32A and a lower side opening portion40where the lower window28(refer toFIGS. 1 and 2) formed in the lower portion32B is disposed. The rear window24(refer toFIGS. 1 and 2) is disposed in the upper side opening portion38. The lower portion32B of the inner panel32is shaped such that its peripheral edge portion protrudes rearward with respect to its part that is on the inner side in the width direction of the vehicle. The outer panel34is disposed on the lower side of the lower window28(refer toFIGS. 1 and 2). The outer panel34is configured to be joined to the peripheral edge portion of the lower portion32B of the inner panel32by an adhesive44(described later with reference toFIG. 4).

The inner panel32is formed of a material that has a relatively small linear expansion coefficient and is unlikely to thermally elongate so that, for example, rigidity is ensured. For example, the inner panel32is formed of iron, an aluminum alloy, carbon-fiber-reinforced plastic (CFRP), or a polypropylene resin (PP resin). According to the first embodiment, the inner panel32is made of iron with a linear expansion coefficient k of 1×10−7l/K or CFRP with a linear expansion coefficient k of 0.5×10−7l/K.

The extension36is a member that is formed to protrude rearward. The extension36constitutes a part of the inner panel32by being superposed from the rear side of the vehicle onto and joined to the middle portion of the lower portion32B of the inner panel32in the width direction of the vehicle. The extension36may be formed of, for example, the same material as the inner panel32. Alternatively, the extension36and the inner panel32may be formed of different materials.

The outer panel34is disposed to face the lower portion32B of the inner panel32in the front-rear direction of the vehicle on the rear side of the inner panel32of the vehicle (outer side of the vehicle). The outer panel34constitutes the design surface of the back door16. In the back door16according to the first embodiment, the outer panel34is configured as an outer lower panel.

The outer panel34is disposed on the rear side of the extension36disposed in the lower portion32B of the inner panel32. The outer panel34is disposed to cover the extension36and face the wall beneath the opening portion40in the lower portion32B of the inner panel32. A stepped portion42is disposed on the lower side of the outer panel34in the up-down direction of the vehicle. The stepped portion42is formed in an inverted U-shape in rear view of the vehicle. The stepped portion42is configured to have a step formed from the front side of the vehicle toward the rear side of the vehicle. More specifically, a front side vertical wall portion35A is formed in the middle portion of the lower portion of the outer panel34in the width direction of the vehicle and the front side vertical wall portion35A is disposed substantially along the up-down and width directions of the vehicle. The stepped portion42is provided with a stepped wall42A obliquely extending substantially rearward from the peripheral edge portion of the front side vertical wall portion35A. In addition, the outer panel34is provided with a rear side vertical wall portion35C disposed substantially along the up-down and width directions of the vehicle from the rear end portion of the stepped wall42A (refer toFIG. 6). In other words, the stepped portion42in the lower portions in the up-down direction of the vehicle that are disposed in both end portions of the outer panel34in the width direction of the vehicle is provided with the stepped wall42A obliquely extending from the front side vertical wall portion35A toward the rear side of the vehicle and the outer sides in the width direction of the vehicle (refer toFIG. 6). The rear side vertical wall portion35C is disposed on the outer panel34and the rear side vertical wall portion35C extends from the rear end portion of the stepped wall42A to the outer side in the width direction of the vehicle.

In order to improve the surface quality, to further reduce the weight, and to further increase the degree of freedom in shape of the outer panel34, the outer panel34is formed of a material that has a linear expansion coefficient larger than the linear expansion coefficient of the inner panel32and is more likely to thermally elongate than the inner panel32. For example, the outer panel34is formed of a polypropylene resin (PP resin), polycarbonate (PC), or an acrylonitrile-butadiene-styrene (ABS) copolymer resin. According to the first embodiment, the outer panel34is made of a PP resin with a linear expansion coefficient k of 7×10−7l/K. The outer panel34and the inner panel32are formed of materials with different linear expansion coefficients as described above. As a result, at a high temperature (such as approximately 80° C.) attributable to paint heating or the like, a thermal elongation difference by a factor of seven to 14 with respect to the inner panel32may occur in the outer panel34.

A stepped portion43is disposed in the lower portion of the inner panel32in the up-down direction of the vehicle as illustrated inFIG. 6. The stepped portion43is at a position that faces the stepped portion42in the outer panel34and forms a step from the front side of the vehicle toward the rear side of the vehicle. More specifically, a front side vertical wall portion33A is disposed in the middle portion of the lower portion of the inner panel32in the width direction of the vehicle and the front side vertical wall portion33A is disposed substantially along the up-down and width directions of the vehicle. The stepped portion43is provided with a stepped wall43A obliquely extending from an edge portion of the front side vertical wall portion33A toward the rear side of the vehicle and an outer side in the width direction of the vehicle. A rear side vertical wall portion33C is disposed on the inner panel32and the rear side vertical wall portion33C is disposed substantially along the up-down and width directions of the vehicle from the rear end portion of the stepped wall43A.

As illustrated inFIGS. 4 and 5, an adhesive surface34A is disposed on the outer edge (peripheral edge portion) of the outer panel34and an adhesive surface32C (refer toFIG. 6) is disposed on the outer edge (peripheral edge portion) of the inner panel32. The adhesive surface34A of the outer panel34and the adhesive surface32C of the inner panel32are joined to each other by the adhesive44. A material providing a relatively high level of adhesiveness between the adhesive surface34A of the outer panel34and the adhesive surface32C of the inner panel32is selected as the adhesive44. In the first embodiment, a polyurethane-based adhesive is used as an example of the adhesive44.

In the middle portion of the outer panel34in the width direction of the vehicle, the outer panel34and the peripheral edge portion of the extension36(refer toFIG. 3) are joined to each other by an adhesive50.

As illustrated inFIGS. 4 to 6, a seal46as an affixed member is affixed to the adhesive surface34A of the rear side vertical wall portion35C in both end portions of the outer panel34in the width direction of the vehicle and the seal46is affixed at a position adjacent to the stepped portion42. In other words, the seal46is affixed to the adhesive surface34A that is adjacent to the stepped portion42on the back face of the outer panel34(surface on the front side of the vehicle). The seal46is configured of a plastic film (tape). The seal46is affixed to a part of the adhesive surface34A of the rear side vertical wall portion35C of the outer panel34, that is, a part of the outer edge (peripheral edge portion) of the outer panel34. As illustrated inFIG. 8, the seal46is affixed to a part of the adhesive surface34A in the lower end portion of the outer panel34in the up-down direction of the vehicle. The seal46is configured to adhere less to the adhesive44than to the adhesive surface34A of the outer panel34to which it is affixed. In other words, the seal46is configured to have a relatively high level of adhesiveness with the adhesive surface34A of the outer panel34to which it is affixed and have a relatively low level of adhesiveness with the adhesive44.

In the vehicular panel structure S20according to the first embodiment, an adhesive layer48is disposed on one surface of the seal46and the seal46is affixed to the rear side vertical wall portion35C of the outer panel34via the adhesive layer48as illustrated inFIGS. 6 and 7. A material that has a relatively high level of adhesiveness with the outer panel34is used for the adhesive layer48. According to the first embodiment, a polyacrylic adhesive layer is used as an example of the adhesive layer48. Polypropylene (PP), polyethylene (PE), or the like is used as the material of the seal46that has a relatively low level of adhesiveness with the adhesive44. Accordingly, a boundary47between the adhesive44and the seal46is configured such that the adhesive force resulting from the adhesive44is rarely exhibited, that is, the bonding strength between the adhesive44and the seal46is rarely exhibited, although the surface of the seal46that is on the side opposite to the adhesive layer48is in contact with the adhesive44. The “affixed member” according to the disclosure is configured to include the seal46and the adhesive layer48. The “affixed member” is configured to have a relatively lower level of adhesiveness with the adhesive44than with the adhesive surface34A of the outer panel34to which it is affixed.

In the first embodiment, the seal46has, for example, a substantially square shape along with a dimension of 20 mm to 50 mm×20 mm to 50 mm.

Hereinafter, the action and effect of the vehicular panel structure S20according to the first embodiment will be described.

In the vehicular panel structure S20, the linear expansion coefficient of the outer panel34differs from the linear expansion coefficient of the inner panel32and the adhesive surface34A of the outer panel34is joined to the adhesive surface32C of the inner panel32by the adhesive44(refer toFIG. 6and so on). The seal46is affixed to a part of the adhesive surface34A of the outer panel34. The seal46adheres less to the adhesive44than to the adhesive surface34A of the outer panel34to which it is affixed.

In the vehicular panel structure S20described above, the seal46is affixed to a part of the adhesive surface34A of the outer panel34and the seal46adheres less to the adhesive44than to the adhesive surface34A of the outer panel34to which it is affixed. As a result, in the region to which the seal46is affixed, a state occurs where the outer panel34is not bound by the adhesive44. In other words, a state of almost no adhesion (non-adhesive portion) occurs in the region. Accordingly, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel32and the outer panel34can be more effectively avoided. In the vehicular panel structure S20, the dimension of the seal46and the position to which the seal46is affixed can be adjusted with ease, and thus positional variations can be reduced compared to, for example, a configuration in which a one-side adhesive portion is disposed as a result of a primer treatment.

In the vehicular panel structure S20, the adhesive44causes the outer edge of the inner panel32and the outer edge of the outer panel34to adhere to each other and the seal46is disposed at a part of the outer edge of the outer panel34(refer toFIGS. 4 and 5). Adhesiveness is ensured between the inner panel32and the outer panel34as the outer edge of the inner panel32and the outer edge of the outer panel34are caused to adhere to each other by the adhesive44. In addition, by the seal46being disposed at a part of the outer edge of the outer panel34, a state occurs where a part of the outer edge of the outer panel34is not bound by the adhesive44, that is, a state of almost no adhesion (non-adhesive portion). As a result, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel32and the outer panel34can be more effectively avoided with adhesiveness ensured between the inner panel32and the outer panel34.

In the vehicular panel structure S20, the stepped portion42is disposed at a part of the outer panel34and the seal46is disposed adjacent to the stepped portion42(refer toFIGS. 4 to 6). Although stress concentration, and distortion in particular, are likely to occur in the vicinity of the stepped portion42of the outer panel34, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel32and the outer panel34can be more effectively avoided as the seal46is disposed adjacent to the stepped portion42.

In the vehicular panel structure S20, the inner panel32and the outer panel34constitute the back door16and the seal46is disposed in the lower end portion of the back door16in the up-down direction of the vehicle (refer toFIG. 8). In the region of the outer panel34to which the seal46is affixed, a state occurs where the outer panel34rarely adheres to the adhesive44(non-adhesive portion) while the adhesive44is in close contact with the outer panel34via the inner panel32and the seal46. At this time, the seal46is disposed in the lower end portion of the back door16in the up-down direction of the vehicle, and the dew condensation water generated in the back door16can be discharged by oozing out between the seal46and the adhesive44(boundary47) and dust and sound movements into the cabin of the vehicle can be further suppressed.

In the vehicular panel structure S20, the seal46is affixed to the outer panel34side, that is, the design surface side. As a result, distortion of the outer panel34as a design surface can be more effectively avoided.

FIGS. 12A and 12Bare sectional views illustrating a back door202that is cut along the width direction of the vehicle. A vehicular panel structure S200according to a comparative example is applied to the back door202.FIG. 13is an enlarged sectional view of the back door202to which the vehicular panel structure S200according to the comparative example is applied.

FIG. 12Ashows a state where the back door202is at a normal temperature without deformation andFIG. 12Bshows a state where the back door202is deformed at a high temperature (such as approximately 80° C.) during paint heating. As illustrated inFIG. 12A, the back door202is provided with an inner panel204and an outer panel206and a peripheral edge portion204A of the inner panel204and a peripheral edge portion206A of the outer panel206are joined to each other by the adhesive44. A protruding portion204B protruding to the outer panel206is formed in the middle portion of the inner panel204in the width direction of the vehicle and the protruding portion204B of the inner panel204is joined by the adhesive44to a middle portion206B of the outer panel206in the width direction of the vehicle.

As illustrated inFIG. 13, the stepped portion42is formed on the outer panel206and the stepped portion43is formed at the position of the inner panel204that faces the stepped portion42. The stepped portion42of the outer panel206and the stepped portion43of the inner panel204are joined to each other by the adhesive44. The inner panel32is formed of a material that has a relatively small linear expansion coefficient and is unlikely to thermally elongate. The outer panel34is formed of a material that has a linear expansion coefficient larger than the linear expansion coefficient of the inner panel32and is more likely to thermally elongate than the inner panel32.

In the vehicular panel structure S200according to the comparative example, the outer panel206is likely to thermally elongate with respect to the inner panel204as illustrated inFIG. 12Bonce the back door202reaches a high temperature (such as approximately 80° C.) during paint heating. At this time, the peripheral edge portion206A of the outer panel206and the middle portion206B of the outer panel206in the width direction of the vehicle are joined to the inner panel204via the adhesive44. As a result, the vicinity of the region to which the adhesive44is attached becomes a portion of sudden rigidity change and distortion occurs in the outer panel206. Then, the distortion may still remain in the outer panel206even after the back door202is cooled and the surface quality of the outer panel206may deteriorate.

In the vehicular panel structure S20according to the first embodiment, in contrast, the seal46is affixed to the part of the outer panel34that is disposed adjacent to the stepped portion42and the region to which the seal46is affixed is in a state of not being bound by the adhesive44, that is, a state of almost no adhesion (refer toFIGS. 4 to 6). Although stress concentration, and distortion in particular, are likely to occur in the vicinity of the stepped portion42of the outer panel34, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel32and the outer panel34can be more effectively avoided as the seal46is disposed adjacent to the stepped portion42.

Second Embodiment

Hereinafter, a vehicular panel structure according to a second embodiment will be described with reference toFIG. 9. The same reference numerals will be used to refer to the components, members, and the like that are common to the first and second embodiments, and detailed description thereof will be omitted.

As illustrated inFIG. 9, a back door16to which a vehicular panel structure S60according to the second embodiment is applied is provided with an inner panel62and an outer panel64. A stepped portion42is formed on the outer panel64and a stepped portion43is formed at the position of the inner panel62that faces the stepped portion42. In the vehicular panel structure S60, a seal46as an affixed member is affixed to the position of an adhesive surface32C of a rear side vertical wall portion33C of the inner panel62that is adjacent to the stepped portion43. A material that has a relatively high level of adhesiveness with the inner panel62is used for an adhesive layer48of the seal46. The seal46is configured to adhere less to an adhesive44than to the adhesive surface32C of the inner panel62to which it is affixed. In other words, the seal46is configured to have a relatively high level of adhesiveness with the adhesive surface32C of the inner panel62to which it is affixed and have a relatively low level of adhesiveness with the adhesive44.

The inner panel32is formed of a material that has a relatively small linear expansion coefficient and is unlikely to thermally elongate. For example, the inner panel32is formed of iron, an aluminum alloy, carbon-fiber-reinforced plastic (CFRP), or a polypropylene resin (PP resin).

The outer panel64is formed of a material that has a linear expansion coefficient larger than the linear expansion coefficient of the inner panel62and is more likely to thermally elongate than the inner panel62. For example, the outer panel64is formed of a polypropylene resin (PP resin), polycarbonate (PC), or an acrylonitrile-butadiene-styrene (ABS) copolymer resin.

In the vehicular panel structure S60, the seal46is affixed to a part of the adhesive surface32C of the inner panel62and the seal46adheres less to the adhesive44than to the adhesive surface32C of the inner panel62to which it is affixed. As a result, in the region to which the seal46is affixed, a state occurs where the inner panel62is not bound by the adhesive44. In other words, a state of almost no adhesion occurs in the region. Accordingly, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel62and the outer panel64can be more effectively avoided. In the vehicular panel structure S60, the dimension of the seal46and the position to which the seal46is affixed can be adjusted with ease, and thus positional variations can be reduced compared to, for example, a configuration in which a one-side adhesive portion is disposed as a result of a primer treatment.

Third Embodiment

Hereinafter, a vehicular panel structure according to a third embodiment will be described with reference toFIGS. 10 and 11. In the third embodiment, the same reference numerals will be used to refer to the components, members, and the like that are common to the first to second embodiments, and detailed description thereof will be omitted.

As illustrated inFIG. 10, a back door16to which a vehicular panel structure S70according to the third embodiment is applied is provided with an inner panel32and an outer panel34. An affixed member72is affixed to the position of an adhesive surface34A of a rear side vertical wall portion35C of the outer panel34that is adjacent to a stepped portion42. The affixed member72is a resin-molded article and is provided with three planar joined portions72A and two recessed portions72B as illustrated inFIGS. 10 and 11. The planar joined portions72A are joined to the adhesive surface34A of the outer panel34and the recessed portions72B are recessed from the planar joined portions72A to the front side of the vehicle in the intermediate portion of the planar joined portions72A in the width direction of the vehicle. The two recessed portions72B of the affixed member72according to the third embodiment are spaced apart from each other in the intermediate portion of the planar joined portions72A in the width direction of the vehicle. The planar joined portions72A are disposed in three different places, one being between the two recessed portions72B and the rest being both sides of the recessed portions72B. The recessed portions72B are configured such that the recessed parts pass along the up-down direction of the vehicle in a state where the planar joined portions72A adhere to the adhesive surface34A of the rear side vertical wall portion35C of the outer panel34.

The affixed member72is configured to adhere less to an adhesive44than to the adhesive surface34A of the outer panel34to which it is affixed. In other words, the affixed member72is configured to have a relatively high level of adhesiveness with the adhesive surface34A of the outer panel34to which it is affixed and have a relatively low level of adhesiveness with the adhesive44. The joined portions72A of the affixed member72are configured to be caused to adhere to the adhesive surface34A of the rear side vertical wall portion35C of the outer panel34by an adhesive layer (not illustrated). In addition, the affixed member72is joined to the adhesive surface34A in the lower end portion of the outer panel34in the up-down direction of the vehicle.

In the vehicular panel structure S70, the affixed member72is affixed to a part of the adhesive surface34A of the outer panel34and the affixed member72adheres less to the adhesive44than to the adhesive surface34A of the outer panel34to which it is affixed. As a result, in the region to which the affixed member72is affixed, a state occurs where the outer panel34is not bound by the adhesive44. In other words, a state of almost no adhesion occurs in the region. Accordingly, the distortion that is attributable to the difference between the linear expansion coefficients of the inner panel32and the outer panel34can be more effectively avoided. In the vehicular panel structure S70, the dimension of the affixed member72and the position to which the affixed member72is affixed can be adjusted with ease, and thus positional variations can be reduced compared to, for example, a configuration in which a one-side adhesive portion is disposed as a result of a primer treatment.

In the vehicular panel structure S70, the two recessed portions72B are disposed in the affixed member72affixed to the adhesive surface34A of the outer panel34and the two recessed portions72B pass along the up-down direction of the vehicle. As a result, the dew condensation water generated in the back door16can be discharged with a high level of reliability through the two recessed portions72B of the affixed member72.

In the vehicular panel structure S70according to the third embodiment, the affixed member72is formed such that the two recessed portions72B pass along the up-down direction of the vehicle. However, the disclosure is not limited thereto and the number of the recessed portions may be changed to one or two or more. In the vehicular panel structure S70according to the third embodiment, the affixed member72is affixed to the adhesive surface34A of the outer panel34. However, the disclosure is not limited thereto and the affixed member72may be affixed to an adhesive surface32C of the inner panel32instead.

The vehicular panel structure S20, S60, S70according to the first to third embodiments is applied to the back door16. However, the disclosure is not limited to the configuration described above. The vehicular panel structure according to the disclosure may be applied to vehicle members other than the back door such as a hood, a side door, and a roof.

The embodiments of the disclosure described above are merely examples and can be implemented in various modified forms. It is a matter of course that the scope of the disclosure is not limited by the embodiments and the disclosure can be implemented in various aspects.