JPH0649959B2 - Vehicle electrodeposition coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle electrodeposition coating method.

(Prior Art) In general, when painting a vehicle, an electrodeposition coating for the purpose of rust prevention is performed on the entire inner and outer panels of a vehicle body as an undercoating step.

As a method of performing the electrodeposition coating, a method of simply immersing the vehicle body in an electrodeposition tank and energizing it has been conventionally known.

(Problems to be Solved by the Invention) As described above, in the case of performing electrodeposition coating by simply dipping the vehicle body in the electrodeposition tank, the vehicle body outer plate is more likely to be caused due to the positional relationship between the vehicle body and the electrodes. Since it is easier to electrodeposit than the inner plate, a thick electrodeposition coating film is formed on the outer plate side, while a thin electrodeposition coating film is formed on the inner plate side, resulting in a non-uniform electrodeposition coating film. May be formed. When the thin electrodeposition coating film is formed on the inner plate side of the vehicle body in this way, there arises a problem that the rust preventive property on the inner plate side (in particular, the inner side surface of the vehicle body) is deteriorated.

The present invention has been made in view of the above points, so as to form a uniform thick electrodeposition coating film on the inner and outer plates of the vehicle body,
The purpose is to improve the rust resistance of the inner plate.

(Means for Solving the Problems) In the method of the present invention, as a means for solving the above problems, a cover member for covering the vehicle body outer plate is attached to the vehicle body outer plate, and the vehicle body is subjected to electrodeposition coating. The first step, the second step of removing the cover member from the outer plate, and the third step of performing electrodeposition coating on the vehicle body with the cover member removed are sequentially performed.

(Operation) In the method of the present invention, the following operations can be obtained by the above means.

That is, after applying the electrodeposition coating with the cover member applied to the outer plate of the vehicle body, first forming the electrodeposition coating film of a predetermined thickness on the inner plate side of the vehicle body, and then removing the cover member to remove the inside and outside of the vehicle body. By applying the electrodeposition coating to the plate again, a uniform and thick electrodeposition coating film is formed on the inner and outer plates of the vehicle body.

(Examples) Hereinafter, some preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 3 show a first embodiment of the present invention.

In the electrodeposition coating method according to the present embodiment, after the cover member 2 for covering the side surface outer plate of the vehicle body 1 is attached, the vehicle body 1 is coated with the cover member 2.
Process K for dipping the oil in the first electrodeposition tank 4 for electrodeposition coating
₁ and the second step K for removing the cover member 2 from the vehicle body 1
_The basic process is to sequentially perform ₂ and the third process K _{3 in} which the vehicle body 1 with the cover member 2 removed is immersed in the second electrodeposition tank 5 and electrodeposition coating is performed again. In this embodiment, a pretreatment step K ₀ for degreasing and surface-treating the vehicle body 1 before the first step K ₁ and a vehicle body 1 after electrodeposition coating after the third step K ₃ And a post-treatment step K ₄ of washing and drying.

The transportation of the vehicle body 1 to each of the processes K _{0 to} K ₄ is performed by a vehicle body transportation line 3 including a transportation conveyor and the like. The electrodeposition coating in the first and second electrodeposition tanks 4 and 5 is carried out by a conventional anion or cation electrodeposition.

Further, as shown in FIG. 2, the cover member 2 attached to the vehicle body 1 in the first step K ₁ is composed of several members 2a, 2a. It is attached only to both sides of the plate.

Therefore, depending on the electrodeposition coating in the first step K ₁ , the third step
As shown by (b) in the enlarged view of the second step of the figure, the outer plate portion (that is, the top plate portion and the front and rear plate portions) and the inner plate portion of the vehicle body 1 which are not covered with the cover member 2 have a predetermined thickness. The electrodeposition coating film is formed. Here, reference numeral 1a indicates an electrodeposition portion,
1b shows the non-electrodeposited portions, respectively.

Further, in the third step K ₃ , the electrodeposition coating film has already been formed not to mention the portions where the electrodeposition coating film has not been formed in the first step K ₁ (that is, the outer plate portions on both side surfaces of the vehicle body 1). The existing parts (that is, the top plate outer plate part, the front and rear plate outer plate part and the inner plate part) are to be electrodeposited, so that a uniform and thick electrodeposition coating film is formed on the inner and outer plates of the vehicle body 1. is there. That is, the throwing power and the film thickness of the electrodeposition coating film on the inner plate portion of the vehicle body 1 can be significantly improved.

When the inner plate portion of the vehicle body 1 is subjected to electrodeposition coating in the first electrodeposition tank 4 as in the present embodiment, the finished skin of the electrodeposited coating film on the inner plate portion is not required so much on the outer plate portion. Therefore, high voltage electrodeposition is possible, and the film thickness of the electrodeposition coating film in the first step K ₁ can be increased.

Needless to say, the work of attaching and removing the cover member 2 to and from the vehicle body 1 in the conventional manufacturing process may be performed manually or mechanically.

A second embodiment of the invention is shown in FIGS. 4 and 5.

In the electrodeposition coating method according to this embodiment, the first step
K ₁ , the second step K ₂ and the third step K ₃ are continuously carried out in the same electrodeposition tank 4.

That is, in the electrodeposition coating method of this embodiment, the cover member 2 is provided on both sides of the vehicle body transport line 3 for transporting the vehicle body 1.
Cover member conveying lines 6, 6 for circulating and conveying the sheet in synchronism with the conveying speed of the vehicle body 1 are arranged in parallel. The cover member 2 of this embodiment is made of a magnet rubber having a shape corresponding to the shape of the side surface of the outer plate of the vehicle body 1. In addition,
As shown in FIG. 5, each cover member transfer line 6 is composed of a portion 6a that runs in parallel with the vehicle body transfer line 3 and a portion 6b that is separated from the vehicle body transfer line 3.

Then, the vehicle body 1 conveyed by the vehicle body conveyance line 3
The cover members 2 which are circulated and conveyed by the cover member conveyance line 6 are attached to the outer plates of both sides, and the inside of the electrodeposition tank 4 is moved while maintaining the state, and the cover members 2 of the vehicle body 1 are covered. After the electrodeless coating is applied to the non-existing portions (that is, the top plate outer plate part, the front and rear plate outer plate part and the inner plate part) (first step K ₁ ), the cover member 2 is transferred to the cover member transfer line 6 by the vehicle body. The vehicle body 1 in the process of being conveyed according to the separation from the line 3
Is automatically removed (second step K ₂ ), and thereafter only the vehicle body 1 is electrodeposited on the inner and outer plates of the vehicle body 1 in the process of being transported by the vehicle body transport line 3 in the electrodeposition tank 4.

When the vehicle body 1 is subjected to electrodeposition coating as in each of the above-described embodiments, in the first step K ₁ , after the electrodeposition coating film having a predetermined thickness is formed on the inner plate portion of the vehicle body 1, the third step K 1 is performed. _In Fig. ₃ , the electrodeposition coating film is formed on the inner and outer plates of the vehicle body 1, and the electrodeposition coating film on the inner and outer plates of the vehicle body 1 has a uniform film thickness. The throwing power and the film thickness can be remarkably improved.

The present invention is not limited to the above embodiments, and it goes without saying that various means may be adopted without departing from the scope of the invention.

(Effects of the Invention) As described above, according to the method of the present invention, electrodeposition coating is performed in a state where the cover member is attached to the vehicle body outer plate, and then the vehicle body inner plate side is first electrodeposited with a predetermined thickness. After forming the film, the cover member is removed and the inner and outer plates of the vehicle body are subjected to electrodeposition coating, so that a uniform and thick electrodeposition coating film can be formed on the inner and outer plates of the vehicle body. Compared with the coating method, the throwing power and the film thickness of the electrodeposition coating film on the inner plate of the vehicle body are significantly improved, and the excellent effect of being able to significantly improve the rust prevention of the inner plate is achieved. can get.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an apparatus used in an electrodeposition coating method according to a first embodiment of the present invention, and FIG. 2 shows a cover member adhered state in the first step in FIG. Enlarged view,
3 (a) and 3 (b) are enlarged views showing a state where the cover member is removed in the second step in FIG. 1, and FIG. 4 is used for the electrodeposition coating method according to the second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a device to be manufactured, and FIG. 5 is a plan view of a main part of the device shown in FIG. 1 ... Car body 2 ... Cover member K ₁ ... 1st process K ₂ ... 2nd process K ₃ ... 3rd process

Claims (1)

[Claims] 1. A first step in which a cover member for covering an outer panel of a vehicle body is applied and electrodeposition coating is performed on the vehicle body, a second step in which the cover member is removed from the outer panel, and a state in which the cover member is removed. The method for electrodeposition coating of a vehicle is characterized by sequentially performing the third step of performing electrodeposition coating again on the vehicle body.