JPS62103399A - Method for preventing secondary sagging of electrodeposition paint - Google Patents

Abstract

PURPOSE:To prevent the generation of the secondary sagging of an electrodeposition paint in the stage of subjecting a material which is to be treated and has projecting parts having holes by providing holes for communicating the bottom and outside of the holes to the peripheral wall of the projecting parts and discharging the electrodeposition paint in the inside of the holes. CONSTITUTION:Grooves are preliminarily provided to the surface of spacers 2 having the holes 3 to contact with a cylinder head cover 1 in the stage of subjecting the cylinder head cover 1 provided with the above-mentioned spacers 2 to electrodeposition painting. The holes 4a, 4b through which the holes 3 in the spacers 3 communicate with the outside when the spacers 2 are integrally formed to the cylinder head cover 1 by spot welding are formed. The electrodeposition paint contained in the holes 3 of the spacers 2 are discharged from the holes 4a, 4b when the cylinder head cover 1 is immersed into an electrodeposition bath vessel and is pulled up from the electrodeposition paint after electrodeposition painting. The electrodeposition paint is, therefore, not left in the holes 3 when the cylinder head cover is sent to a sintering stage. The good electrodeposition coated film is thus obtd. without the generation of the secondary sagging of the electrodeposition paint.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for preventing secondary sagging of electrodeposition paint. More specifically, it relates to a method in which the number of man-hours and polishing fees for prevention can be omitted and saved, thereby reducing costs.

[Prior Art] Cylinder head covers and the like are usually used with only electrodeposition coating applied. A spacer for connecting the air cleaner is attached to the cylinder head cover by spot welding, and the spacer has a female threaded hole for bolt connection formed on its circumferential surface in the center.

For the electrodeposition coating of the rad cover to the cylinder, there is a fourth layer in the electrodeposition bath.
This is done by immersing the cylinder head cover placed on a pallet (5) as shown in the figure. In that case, depending on the position in which the cylinder head cover is mounted on the pallet (5), the cylinder head cover may be taken out of the tank with the electrodeposited paint still in the hole (3) of the spacer (2) and sent to the subsequent baking drying process. During baking and drying, the electrodeposition paint accumulated in the holes (3) is blown out due to the influence of heat, causing so-called secondary sagging (6) of the electrodeposition paint (as shown in FIG. 5). As a result, there was a problem that the appearance finish of the Den-I 1 coating film was poor.

Therefore, a heat-resistant masking tape ('7) as shown in FIG. 6 is pasted onto the hole (3) of the spacer (2) to prevent paint from entering during electrodeposition coating.

[Problems to be Solved by the Invention] However, the method requires many man-hours to apply and remove the masking tape, requires a heat-resistant tape for masking, and does not apply the masking tape in a perfect state. Otherwise, there is a problem of producing defective products.

In view of the above-mentioned points, an object of the present invention is to provide a method for preventing secondary dripping of electrodeposition paint, which can reliably prevent secondary dripping of electrodeposition paint, and can omit and save man-hours and materials. do.

[Means for Solving the Problems] In the present invention, when electrocoating a workpiece having a protrusion with a hole, an appropriate number of holes are provided on the peripheral wall of the protrusion to communicate the bottom of the hole with the outside. The present invention relates to a method for preventing secondary sagging of electrodeposition paint, which comprises providing a hole and discharging the electrodeposition paint that has entered the hole during electrodeposition coating from the hole when the object to be treated is taken out of the tank.

[Example〕 Next, the present invention will be explained in detail based on the drawings.

1 is a front view showing a cylinder head cover equipped with a spacer provided with holes according to the method of the present invention; FIG. 2 is an enlarged sectional view taken along the line (X)-(X) of FIG. 1 showing the spacer portion in detail; FIG. 3 is a plan view of the cylinder head cover shown in FIG. 2 showing the spacer portion in detail.

In Figs. 1 to 3, (1) is a rad cover for the cylinder. The cylinder head cover (1) shown in Fig. 1 is
The attitude of the machine being mounted on the pallet (5) is being shown. An air cleaner connection spacer (2) is attached to the cylinder head cover (1) by spot welding.

A hole (3) is formed in the center of the spacer (2) with a threaded hole (3) for bolt connection on the circumferential surface. Spacer (2
) is in contact with the cylinder head cover (1), a groove is provided prior to spot welding, and the groove is in contact with the spacer (2).
) forms holes (4a) and (4b) when attached to the cylinder head cover (1). chain hole (4a
), (4b) are spacers (2) as shown in Figure 1.
It is provided so that the bottom of the hole (5) and the outside communicate with each other on the lower side of the hole (5).

The cylinder head cover (1) is placed on a pallet (5) as shown in FIG. 4 and immersed in an electrodeposition bath.

At this time, the electrodeposition paint enters the hole (3), but this electrodeposition paint is discharged from the hole (4) when the pallet (5) is pulled up from the electrodeposition bath after the electrodeposition coating is completed. Therefore, when the cylinder head cover (1) is sent to the subsequent baking and drying process, no electrocoating paint remains in the holes (3) and secondary sagging of the electrocoat does not occur, ensuring a good electrocoating film. I can do it.

The cross-sectional shape of the hole (4) may be any other suitable shape such as a triangle or a semicircle in addition to the rectangle shown in the embodiment. Further, the size may be such that the electrodeposition paint can be easily removed.

The number of holes (4) may be selected as appropriate depending on the type of part having the holes (3) such as the spacer (2), but in general 1.
~2 is the standard.

[Effects] As explained above, in the present invention, when performing electrodeposition coating, the paint that enters the hole in the protruding part of the object to be treated is discharged from the hole provided in the part with the extraction hole. It is possible to reliably prevent secondary sagging, eliminate the man-hours required to prevent secondary sag, save on masking tape and other prevention materials, and eliminate the need to carry out electrocoated paint, leading to cost reductions. There is an effect that it can be done.

4 Brief explanation of the drawings - Fig. 1 is a front view showing a rad cover to a cylinder equipped with a spacer provided with holes according to the method of the present invention, and Fig. 2 is a view (X)-- of Fig. 1 showing the spacer part in detail. (X) line enlarged sectional view, Figure 3 is a plan view of the cylinder head and cover shown in Figure 2 showing the spacer part in detail, Figure 4 is a pallet on which objects to be treated are placed when performing electrodeposition coating. Figure 5 is an explanatory diagram showing how secondary sagging of electrodeposition paint occurs, and Figure 6 is a spacer with masking tape pasted on the hole opening to prevent electrodeposition paint from entering. FIG.

(Main symbols on drawings) (1) Rad cover to Niji Linda (21, spacer (3); hole (4): Hole Patent applicant: Daihatsu Motor Co., Ltd. Fang 1 diagram 2 years old 3 years old

Claims (1)

[Claims] 1. When electrocoating a workpiece that has a protrusion with a hole, an appropriate number of holes are provided in the peripheral wall of the protrusion to communicate the bottom of the hole with the outside, and the holes that enter the hole during electrocoating are provided with an appropriate number of holes that communicate with the outside. A method for preventing secondary sagging of electrodeposition paint, characterized in that the electrodeposition paint is discharged from the hole when an object to be treated is discharged from the tank.