JPS5817009B2 - Heat treatment method for outer panel joints of automobile bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat treating an outer panel joint of an automobile body.

An automobile body is completed by joining various panel parts, and each joint has a variety of cross-sectional shapes.

In particular, in the joint parts that affect the surface appearance of the body, it has been put into practical use to make a recess from the general surface, weld the two sheet metal materials together at this hollow part, and then fill in the hollow with solder.

Typical places where such joining means are used are:
There is a joint between the roof panel and the side panel, and this is a very important joint both in terms of appearance and against vibration loads during driving.

If we look at the conventional method of processing the joints of the automobile body for the joints between the roof panel and the side panels, we can see a sketch of a portion of the left rear pillar in Figure 1A and a sectional view B taken along the a-a line in Figure 1A.
As illustrated in , the edges of the steel plate of the roof panel 1 and the steel plate of the side panel 2 are pressed to form a recess 3, and then joined by spot welding or the like.
is filled with solder 4 containing lead, and then the excess solder 4' is removed by polishing to match the curved surface of the body.

However, in this conventional method, since the solder has high fluidity and a high specific gravity in the molten state, a phenomenon occurs in which the solder drips due to its own weight during filling. The shelf part is intentionally provided.

Furthermore, when excess solder is polished, solder particles scatter into the air and contaminate the working environment.

In particular, since solder contains lead, there is a risk of chronic poisoning due to inhaling solder powder over a long period of time, and there is a desire to develop a new treatment method that does not use solder.

Furthermore, there are also problems such as the electrodeposition coating used in the final coating being difficult to adhere to the solder parts, and the paint on the solder joint parts gradually blistering.

The present invention is based on a combination of three main elements: the epoxy resin composition, the concave shape of the joint, and far-infrared heating. It has a special relationship with

That is, the present invention uses an epoxy resin composition to fill the hollows at the joint between the roof and side panels of an automobile body, and employs a movable far-infrared heating device for curing the composition. It is characterized by being able to move integrally with the body while maintaining a certain distance.

Since the manufacture of automobiles relies on conveyor systems, shortening the curing time becomes an extremely important issue when adopting a processing method using a thermosetting resin such as the present invention.

In the present invention, this problem is solved by employing the above-mentioned far infrared curing method, and a treatment method using a thermosetting resin is made possible for the first time.

Therefore, the heating device employed in the method of the present invention will be described.

Generally, a tunnel method is used to heat objects flowing on a belt conveyor.

However, when the heating point is only a small part of the automobile body as in the present invention, it is wasteful to install a tunnel-shaped heating device that covers the belt conveyor, and it is also expensive and uneconomical.

Furthermore, if the treated area is a part of the rear pillar shown in FIG. 1, the heater 5 fixed as shown in FIG. It is difficult to heat and harden uniformly.

Therefore, in the method of the present invention, in order to uniformly heat the joint, a far-infrared heater made to match the shape of the joint is moved together with the body on the belt conveyor while maintaining a constant distance from the joint only during heating and curing. Use a heating device that is precisely configured.

FIG. 4 shows an embodiment of the heating device of the present invention.
A wire rope 10 is connected to a hoist 9 running on an overhang rail 8 provided parallel to a belt conveyor 18.
A far-infrared heater 12 is attached to a frame 11 suspended by a frame 11.

A balancer 13 is attached to the frame 11 for adjusting the frame to keep it horizontal.

This heating device comprises a body 1 with a joint 17 to be treated.
6 is moved on the belt conveyor 18, it is lowered and attached to the frame 11, and the positioning hook 14 and the roof drip fixture 15 keep the joint 17 of the body 16 to be processed and the far infrared heater 12 at a certain distance. It is fixed to the body to keep it in place.

A heating device fixed to the body is moved together with the body as the belt conveyor moves.

After moving with the body for the curing time, the hooks and fixtures are removed and returned to the original position.

A normal far-infrared heater is used as the far-infrared heater used in the present invention, but it is necessary to make it as small and lightweight as possible, and to make the radiation intensity uniform by leaving a certain gap in the pillar shape. It is preferable that the insulation is perfectly arranged, that the insulation is perfect, and that there is adequate heat retention.

FIG. 5A shows an embodiment of a far-infrared heater that is preferably used. In the far-infrared heater 19, band heaters 20 are arranged in parallel in a heat insulating material 22 with an insulator 21 interposed therebetween. It is contained in 23.

FIG. 6 is an emissivity-wavelength characteristic curve of the band heater 20, in which the horizontal axis represents the wavelength μ and the vertical axis represents the emissivity ε.

Note that this characteristic curve is obtained when the heater surface temperature is set at 500°C.

In an actual heating device, two such far-infrared heaters 19 are set so as to face each other on both sides of the pillar in order to match the shape of the pillar of the heating section, as shown in FIG. 5B.
This is covered with a cover 25 having an insulating contact prevention flange 24.

In addition, if there is a change in the shape of the outer skin of the car body on the conveyor line, in other words, even if different models of cars flow, by making a heater that matches the shape of the outer skin in advance and replacing it as necessary, it will be possible to prevent the car body from becoming dirty. Since the material to be filled is an unmolded epoxy resin composition, it can be used satisfactorily.

The far-infrared heater 12 shown in FIG. 4 is such a far-infrared heater set.

After the epoxy resin composition is cured in this manner, the excess portion is removed to match the curved surface of the body.

In a preferred embodiment of the present invention, this removal step is carried out in two stages.

As the epoxy resin used in the present invention, commercially available ordinary epoxy resins are used, such as epoxy resins obtained from an acetone condensate of bisphenol A or resorcinol and epichlorohydrin, polyorthocresol formaldehyde poly(2,3-epoxy Epoxidized novolac resins such as puruvyl) ether and polyphenol formaldehyde poly(2,3-epoxypropyl) ether, and cycloaliphatic epoxy resins such as polyglycidyl esters of polycarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid. can give.

As the curing agent for the epoxy resin, conventionally used amine-based or acid anhydride-based curing agents are used, such as m-phenylenediamine, diethylenetriamine, triethylenetetramine, tetra(hydroxyethyl)diethylenetriamine, benzyldimethyl Examples include amino- or polyamide-based curing agents such as amine, dicyandiamide, or imidazole, and acid anhydride-based curing agents such as phthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, and pyromellitic dianhydride.

Furthermore, there is no particular limit to the amount of such curing agent used;
It may be the same as a conventional epoxy resin composition.

It is preferable to use a boron trifluoride complex amine as a curing accelerator when imidabur is used as a curing agent, and to use a curing accelerator such as furfuryl alcohol or carbolic acid when a polyamide curing agent is used as a curing agent.

Talc, silica, iron powder, aluminum powder, etc. are used as fillers, and the amount used is 20 to 1 part per epoxy resin.
Approximately 50% (weight %, the same applies hereinafter) is used.

In addition, since the hollow part is where vibrations are applied, flexibility imparting agents such as Epicote 871 and Epicote 872 (both manufactured by Shell Chemical Co., Ltd.) are used to impart flexibility to the epoxy resin. Aerosil, silica, mica, etc. may be added as an anti-sagging agent.

By using such a heat treatment method, it is possible to quickly produce a product that does not take up much space, requires minimal energy, has good product quality, especially that no distortion remains on the outer panel of the automobile body, and can overcome lead pollution.

[Brief explanation of drawings]

FIG. 1A is a sketch of a part of the left rear pillar of an automobile body, FIGS. 1B and C are sectional views taken along line a-a of FIG. 1A, and FIG. 2 is a sectional view of an example of the shape of the recess in the present invention. , 3rd
The figure is a schematic diagram of heating by a fixed heater, Figure 4 is a schematic diagram of an example of a heating device used in the method of the present invention, and Figure 5A is a schematic diagram of an example of a far-infrared heater used in the method of the present invention. 5B is a schematic diagram of an example of a far-infrared heater set of the heating device shown in FIG. 4, and FIG. 6 is a characteristic curve of the far-infrared heater shown in FIG. 4. Reference numbers in drawings: 1: Roof panel, 2: Side panel, 3
: Kubomi, 4: Solder, 5: Fixed heater, 6: Joint location on side of body, 8: Overhang rail, 11: Frame,
12: Far infrared heater, 17: Joint part, 20: Band heater, 22: Heat insulating material, 24: Contact prevention flange.

Claims (1)

[Claims] 1 Filling the hollow of the outer panel joint of an automobile body with an unmolded epoxy resin composition, and heat-treating the epoxy resin composition with a far-infrared heater, the far-infrared rays are heated to almost the same shape as the outer panel joint. A heater is movably arranged above the car body placed on a belt conveyor,
Only when the epoxy resin composition is heated and cured, the unmolded epoxy resin composition is lowered onto the car body while maintaining a certain distance from the outer panel joint of the car body, and moved along with the car body on the belt conveyor to heat the unmolded epoxy resin composition. A method for heat treatment of an outer panel joint of an automobile body, characterized by hardening the joint.