JPH0356410Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to the upper structure of an automobile back door, and particularly relates to an improvement to make it suitable for electrodeposition coating.

Conventional Technology Automobile painting is performed multiple times, including an undercoating process, an intermediate coating process, and a topcoating process.In the undercoating process, whose main purpose is rust prevention, doors, etc. are generally placed in an electrodeposition tank filled with water-soluble paint. The body of the vehicle with the attached is immersed in an electrodeposition coating, and in addition to the exterior surface, the interior of the biller and doors are also painted at the same time. Therefore, if air remains inside the biller or door when immersed in the electrodeposition tank, there is a risk of paint defects.

Here, in the case of an automobile back door 1 as shown in Fig. 4, there are a plurality of hinge mounting holes 2 and insertion of a harness such as a harness or a wash tube in the upper part of the passenger compartment side as shown in Fig. 5. Since the holes 3 are open, air will be exhausted through these during electrodeposition coating. FIG. 6 shows a specific cross section of the upper part of the back door 1 along the hinge mounting hole 2, and shows the upper edge 4 of the outer panel 4.
a is folded back and hemmed so as to wrap around the upper edge 5a of the inner panel 5, and both panels 4 and 5 are integrated. In addition, 6 is rain force. Furthermore, after the electrodeposition coating is performed and before the intermediate coating process, a sealing material 8 made of a synthetic resin material or the like is applied along the tip 7a of the folded portion 7 of the outer panel 4.
is applied to ensure even more reliable rust prevention at the hemming area. (For example, Nissan Motor Co., Ltd.)
(See "Caravan Homey Maintenance Manual" published in September 1981) Problems that the invention aims to solve However, in the upper structure of the back door 1 as described above, as is clear from Fig. 6, the hinge mounting Strictly speaking, the holes 2, etc. are not located at the top of the backdoor 1, so air remains in the space 9 between both panels 4 and 5 above this point, and the paint does not reach the hemming area. may not be widely available. As a result, there was a risk that rust would develop early from inside the upper part of the back door 1.

In addition, some sliding doors have a small hole for air vent formed in the upper end surface in advance, which is closed with a separate plug after painting, but the upper surface is outside the vehicle, as in the case of the upper part of back door 1. If it is exposed to the air, it must be formed at a relatively low position on the inside of the vehicle like the hinge mounting hole 2, etc., and therefore it is not as effective, and the number of parts is required to mount a separate plug. There is also a problem that the number of man-hours increases.

Means for Solving the Problems In order to solve the above-mentioned problems, this invention has a back door upper structure in which the upper edge of the outer panel is folded back and hemmed to wrap around the upper edge of the inner panel, and both panels are integrated. An air vent hole communicating with the space between both panels is formed near the upper edge of the inner panel in contact with the tip of the folded portion of the outer panel, and a sealing material is attached along the tip of the folded portion of the outer panel. The air vent hole is then closed.

Function The above sealing material is applied after electrocoating, and air vent holes are opened to the outside during electrocoating. Therefore, when immersed in an electrodeposition tank, air is quickly discharged from the inside of the back door, and the adhesion of paint is not inhibited. In particular, since the air vent hole is located near the hemming portion, that is, at the top of the bag-shaped space, air can be completely removed from the inside, and the coating will be applied sufficiently.

Further, the air vent hole is simultaneously blocked by the process of attaching a sealant that is generally performed along the tip of the folded portion of the outer panel.

Embodiment FIG. 1 is a sectional view showing an embodiment of the upper structure of a back door according to this invention.
5 shows a cross section near the center, which is the highest position, that is, along the - line in FIG.

In this back door 1, the upper edge 4a of the outer panel 4 is the upper edge 5 of the inner panel 5, as in the conventional one.
It is folded back and hemmed to wrap around a.
Both panels 4 and 5 are integrated. An air vent hole 10 as shown in FIG. 2 is formed near the upper edge of the inner panel 5 in contact with the tip 7a of the folded portion 7 of the outer panel 4, and communicates with the space 9 between the panels 4 and 5. are doing. Even if the air vent hole 10 is provided at only two locations in the center of the back door 1, a sufficient effect can be obtained, but it is preferable to provide the air vent hole 10 at a plurality of locations in the vicinity thereof. Incidentally, as shown in FIG. 3, the air vent hole 10 may be formed by cutting out the inner panel 5 from the upper end.

Therefore, during electrodeposition painting in the undercoating process performed by dipping the car body in an electrodeposition tank, the air between both panels 4 and 5 is reliably discharged through the air vent hole 10, and no air bubbles remain. This prevents paint defects due to

On the other hand, in the folded part 7, after the electrodeposition coating is performed and before the intermediate coating process, the sealing material 8 is applied along the tip of the folded part 7 as described above. A large amount of sealant 8 is applied to the sealant 8.
At the same time, the air vent hole 10 is closed.

Therefore, in the completed state, the space 9 inside the back door 1
is sealed to prevent rainwater and the like from entering through the air vent hole 10. At the same time, the air vent hole 10 is closed by the sealant 8 necessary for rust prevention of the hemming part as described above.
Of course, there is no need for a separate member such as a plug, and there is no substantial increase in the number of man-hours.

Effects of the invention As is clear from the above explanation, the upper structure of the back door according to this invention allows the paint to be sufficiently distributed to the upper corners of the inside of the back door during electrodeposition coating in the undercoating process. This allows for accurate painting and prevents rusting due to poor painting. Moreover, no separate member or new process is required to close it, and the appearance will not be impaired.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of this invention; Fig. 5 is a sectional view taken along the - line, Fig. 2 is a perspective view of the main part of the inner panel, and Fig. 3 is a different embodiment of the air vent hole. 4 is a perspective view of an automobile equipped with a back door, FIG. 5 is a rear view of the back door, and FIG. 6 is a sectional view taken along the line - in FIG. 5 showing the conventional back door upper structure. be. 1...back door, 4...outer panel, 5...
...Inner panel, 7...Folded portion, 8...Sealing material, 9...Space, 10...Air vent hole.

Claims (1)

[Scope of utility model registration request] In the upper structure of the back door which is formed by folding the upper edge of the outer panel so as to wrap around the upper edge of the inner panel and hemming the upper edge of the inner panel and integrating both panels, both panels are placed near the upper edge of the inner panel where the upper edge of the inner panel is in contact with the tip of the folded part of the outer panel. 1. An upper structure for a back door, characterized in that an air vent hole communicating with the space between the back doors is formed, and the air vent hole is closed by a sealing material attached along the tip of the folded portion.