JPH0314918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrodeposition drying oven provided in a process after electrodeposition coating of a vehicle body in which a door is incorporated.

(Prior technology) The car body with electrodeposition paint applied to its surface using an electrodeposition layer is sent to the next process, an electrodeposition drying oven. Conventionally, the car body is heated in the drying oven from room temperature to around 160°C to 200°C. The electrodeposited coating was simply dried and cured.

(Problem to be Solved by the Invention) However, since the car body is simply dried, when the temperature of the car body rises to around 100°C, in the case of a car body with a door installed, the temperature rises as shown in Figs. As shown in the figure, the electrodeposition liquid L accumulated in the hemming part 19 at the bottom of the door 13 boils and blows out from the hemming part 19, and falls on the upper surface of the side sill 12, and the fallen electrodeposition liquid L is dried and hardened as it is on the side sill 12. This results in an ED sagging defect that has a poor appearance. For this reason, in the past, the appearance was corrected by scraping off the defective ED sagging areas in the post-drying process, but this type of repair work requires skill, and excessive scraping can reduce the film thickness of the electrodeposited paint. The thinness caused problems with rust prevention, and the man-hours were also becoming more complicated.

Therefore, an object of the present invention is to use air blow to blow away the electrodeposited liquid that overflows from the bottom of the door to the top surface of the side sill during the rising process of the car body in which the door is installed, and to eliminate the electrodeposited liquid that boils and blows out from the bottom of the door. To provide an electrodeposition drying oven for a car body, which almost eliminates ED sag defects by forcibly rinsing with pure water.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, the present invention provides a method for applying heat to several points in the electrodeposition drying oven 1 in the section where the vehicle body 11 is heated from room temperature to about 180°C. An air nozzle device 21 that intensively blows air to the lower part of the door 13 and the side sill 12 is provided, and pure water is provided to intensively wash the lower part of the door 13 and the side sill 12 in areas where the vehicle body temperature is at least around 100°C. It is characterized by being equipped with a spray auto gun 31.

(Function) During the temperature rising process of the vehicle body 11 being transported in the drying oven 1, the lower part of the door 13 and the side sill 12 are intensively blown with air at several locations by the air nozzle device 21, so that air overflows from the lower part of the door 13. The electrodeposition liquid L is blown away and is prevented from falling onto the upper surface of the side sill 12.

In particular, at the point where the electrodeposition liquid L boils at around 100°C, the electrodeposition liquid that is blown out due to boiling is forcibly washed away by the pure water jetted out from the pure water spray auto gun 31, and also blown out due to the mixing of pure water. The electrodeposition solution is diluted. Therefore, even if the electrodeposition liquid falls on the top and side surfaces of the side sill 12,
It will be mixed with pure water and only a small amount will remain in a diluted state.

Furthermore, during the next temperature raising process, the electrodeposited liquid remaining on the side sill 12 and diluted by pure water is blown off by the air nozzle device 21, and all of the ED sagging defects on the side sill 12 are removed. Most will be eliminated.

In this way, the electrodeposited coating film is dried and cured with no or almost no ED sagging defects.

(Example) Examples will be described below based on the accompanying drawings.

FIG. 1 shows a schematic plan view inside the electrodeposition drying oven. It consists of two consecutive heating sections. As shown in FIGS. 4 to 7, the inner panel 16 of the door 13 installed on both sides of the vehicle body 11 changes from room temperature to the center of the first zone.
50℃, 80℃ in the center of the second zone, 100℃ in the center of the third zone, 140℃ in the center of the fourth zone
The drying oven 1 is configured so that the temperature reaches 170°C in the central part of the fifth zone, and the temperature is further increased to about 180°C near the outlet 3.

The car body 11 to be transported into the drying oven 1 is placed on a conveyor 6, which runs on rails 8, 8 by a conveyor 7, and is hinged to both sides of the car body 11 at its front end. The door 13 is constructed by combining an inner panel 16 inside an outer panel 14, and a sash 18 is raised above the inner panel 16. The lower part of the outer panel 14 is folded to surround the lower edge of the inner panel 16 to form a hemming part 19,
The upper surface of the side sill 12 of the vehicle body 11 faces below, a plurality of openings 17 are formed in the inner panel, and a plurality of stiffeners 15 are supported on the inner surface of the outer panel 14.

Furthermore, three pairs of air nozzle devices 21 are installed on the left and right sides of the center of each of the first, second and fifth zones in the drying oven 1, and a pair of air nozzle devices 21 are installed on the left and right of the center of the third zone. A water spray auto gun 31 is installed, and furthermore, a pair of air nozzle devices 21 and a pair of pure water spray auto guns 31 are installed on the left and right sides of the center of the fourth zone.

The air nozzle device 21 is as shown in FIG. 2, and has a lip-shaped opening 24 formed at the tip of a nozzle body 23 fixed to a substrate 22 fixed to the side wall 4 of the drying oven 11, and this lip-shaped opening 24 is covered. A blowout nozzle 26 is fitted, and a flat blowout port 27 is formed at the tip of the blowout nozzle 26, and 25 is an air supply port. Pressurized air is ejected from the flat air outlet 27 in a horizontally wide pattern.

Such an air nozzle device 21 is shown in FIGS. 4 and 5.
As shown in the figure, three pairs are installed at the center of the left and right side walls 4, 4 in the first zone, second zone, and fifth zone, respectively, along the conveyance direction. That is, the first and second air nozzle devices 21a and 21b are installed obliquely upward so as to face the top and side surfaces of the side sill 12, and the third air nozzle device 21
c is installed horizontally so as to face the lower edge of the door 13 and the upper surface of the side sill 12.

The pure water spray auto gun 31 is as shown in FIG.
A blowout nozzle 34 is attached to the tip of the gun body 33 fixed to the
A needle valve 35 for opening and closing the blow-off nozzle 34 is built into the gun body 33, and a cylinder 38 containing a piston 37 operated by air pressure from an air inlet 36 is provided at the rear of the gun body 33. The needle valve 35 is connected to the piston 37,
When the needle valve 35 retreats, the pure water forced through the pure water supply port 41 mixes with pressurized air from the air supply port 42 and is ejected from the blow-off nozzle 34.

A pair of such pure water spray autoguns 31 are installed at the center of the left and right side walls 4, 4 in the third zone as shown in FIGS. 9 and 10. That is, the pure water spray auto gun 31 is installed horizontally so as to be directed toward the lower edge of the door 13 and the upper surface of the side sill 12.

Further, as shown in FIGS. 11 and 12, a pair of air nozzle devices 21 are installed in the center of the left and right side walls 4, 4 in the fourth zone,
Immediately after that, a pair of the pure water spray auto guns 31 are also installed. That is, the air nozzle device 21 is installed obliquely upward so as to face the upper surface and side surface of the side sill 12, and immediately after that, the pure water spray auto gun 31 is installed horizontally so as to face the lower edge of the door 13 and the upper surface of the side sill 12.

In the above process, the vehicle body 11 on the carrier vehicle 6 is held with the left and right doors 13 in a half-open state by an appropriate jig, etc., and is immersed in an electrodeposition bath as known in the prior process to the drying oven 1. After applying electrodeposition paint to the surfaces of the vehicle body 11 and the door 3, the vehicle body 11 and the door 3 are transported into the drying oven 1.

Vehicle body 11 carried into drying oven 1 through loading port 2
The temperature is first raised from room temperature to 50°C in the center of the first zone, and further to 80°C in the center of the second zone. During this heating process, the temperature inside the door 13 increases and the electrodeposition liquid L overflows from the lower hemming part 19 as shown in FIGS.
The overflowing electrodeposition liquid L is blown away by the three air nozzle devices 21a, 21b, and 21c provided in both sections of the zone, and is prevented from falling onto the upper surface and side surface of the side sill 12. That is, in each zone as shown in FIG. 4 and FIG. The falling electrodeposition liquid L can be blown off, and then the lower edge of the door 13 and the side sill 1 can be blown off by the horizontal third air nozzle device 21c.
Since the upper surface of the door 13 is blown with air, the electrodeposition liquid scattered on the outer surface of the lower edge of the door 13 can be blown off without being scattered on the upper surface of the side sill 12.

And the car body 11 is 100 in the center of the third zone.
℃, and here the electrodeposition liquid boils and blows out from the hemming part 19. As shown in FIGS. Since it sprays vigorously, the electrodeposition solution can be forcibly washed away.

Next, the vehicle body 11 is further moved in the center of the fourth zone.
The temperature is raised to 140°C, and the electrodeposition liquid continues to boil and blow out. At this point, as shown in FIGS. 11 and 12, the upper and side surfaces of the side sills 12 are first blown with air using the upward air nozzle device 21. ,
The electrocoating liquid can be blown away to prevent it from falling onto the side sill 12, and then the horizontal pure water spray auto gun 31 will spray the pure water forcefully onto the lower edge of the door 13 and the top surface of the side sill 12. can be forcibly washed away again.

Therefore, the electrodeposition liquid does not adhere to the side sill 12, and even if it does adhere, it becomes diluted due to the mixing of pure water and only a very small amount remains.

Then, the temperature of the vehicle body 11 is further increased to 170° C. in the center of the next fifth zone, but here again, as shown in FIGS. 4 and 5, the three first to third air nozzle devices 21a, 21b are , 21c, the upper and side surfaces of the side sill 12 and the lower edge of the door 13 are blown with air in stages, so that the pure water and the diluted electrodeposited liquid can be finally blown off in those areas.

In this manner, the electrodeposited coating film on the surface of the vehicle body 11 is further heated to about 180° C. with no or almost no ED sagging defects, and then the vehicle body 11 is carried out from the carry-out port 3.

In this way, the electrodeposited coating can be dried and cured with no or almost no ED sag defects, and even if there is a very slight ED sag defect, it can be corrected by simple scraping after the intermediate coat has dried. Since it can be sufficiently applied, it is possible to improve the rust prevention effect, which is the main objective of electrodeposition coating.

(Effects of the Invention) As described above, according to the present invention, in an electrodeposition drying oven for a car body, the lower part of the door and the side sill part are intensively blown with air at several locations, and the temperature is particularly high at around 100°C, where the electrodeposition liquid boils. By forcibly washing away the parts with pure water, it is possible to almost eliminate ED sagging defects, simplify the man-hours, and increase the rust prevention effect.

[Brief explanation of the drawing]

Figure 1 is a schematic plan view of the inside of the electrodeposition drying oven, Figure 2 a
3 and b are a cutaway plan view of the air nozzle device and a front view of its nozzle, FIGS. 3a and 3b are a cutaway plan view of the pure water spray auto gun and a front view of its nozzle, and FIG. Cross section of zone 5,
Figure 5 is a cross-sectional view taken along the line A-A in Figure 4, Figure 6 is a cross-sectional view taken along line B-B in Figure 4, Figure 7 is a view taken in the direction of arrow C in Figure 6, and Figure 8 is a conventional problem. The sixth point also points out that
An enlarged view of part D in Figure 9, Figure 9 is a cross-sectional view of the third zone, Figure 10 is a cross-sectional view taken along line E-E in Figure 9, Figure 11 is a cross-sectional view of the fourth zone, and Figure 12 is a cross-sectional view of the fourth zone. Figure 11F
-F line sectional view. In the drawings, 1 is a drying oven, 4 is a side wall, 11 is a vehicle body, 12 is a side sill, 13 is a door, 19 is a hemming part, 21 is an air nozzle device, 31 is a pure water spray autogun, ,,,, is a zone It is.

Claims (1)

[Scope of Claims] 1. After applying electrocoating to the car body in which the door is incorporated, the car body is heated from room temperature to 180°C in an electrocoating drying oven that heats the car body to dry and harden the electrocoated paint on the surface. Air nozzle devices that intensively blow air to the lower part of the door and side sill will be installed at several locations in the section where the vehicle body temperature reaches approximately 100°C. An electrodeposition drying oven for car bodies, which is characterized by being equipped with a pure water spray auto gun that performs intensive water washing. 2. In claim 1, the air nozzle device is disposed at each location where the vehicle body temperature is around 50°C, around 80°C, around 140°C, and around 170°C, and when the vehicle body temperature is around 100°C and The pure water spray auto gun is arranged at each location where the temperature of the vehicle body reaches around 140°C, and the pure water spray auto gun is arranged immediately after the air nozzle device at the location where the vehicle body temperature becomes around 140°C. Electrodeposition drying oven for car bodies.