JPS58188583A - Joining method of outside plate of vehicle - Google Patents

Abstract

PURPOSE:To join the outside plates of a vehicle without any negative influence on joint strength and painting by interposing an adhesive agent in a superposed joint part of the outside plates, and spot welding said part then covering the part exposed on the outside surface with a coating material and painting the outside surface. CONSTITUTION:Outside plates 1a, 1b are superposed and are adhered and welded in superposed joint parts 2a, 2b, whereafter a coating material 6 is packed in the part of adhesive 4 exposed on the outside surface, that is, the recess produced on the forward end side of the plate 1b. Electrodeposition painting 8 is thereafter applied as undercoating paint on the outside surfaces 3a, 3b of the plates 1a, 1b. A body sealer 9 is then packed in the recess formed after packing of the material 6 in order to prevent the formation of rust in the edge part of the other plate 1b and to level off the surface. After the surface of the joined part is leveled off and coated thereon with undercoating as mentioned above, the entire outside surface is coated with middle coat and finish painting to form paint films 10, 11, whereby the joining is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining vehicle skins.

For example, in medium or large vehicles such as microbuses,
Because the outer panel cannot be formed from a single pressed product,
The exterior is formed by joining multiple pressed products, and spot welding has traditionally been used as the joining method. As is well known, joining exterior panels by spot welding involves welding multiple points on the exterior panel, and does not weld the entire area to be welded, so the joint strength is slightly lower and the outer panel may be damaged. If a load is applied for some reason, the outer panels that are joined to each other may move slightly relative to each other at the welding area. There is a risk that the body sealer filled in the joints may crack, or the paint applied to the outer surface of the outer panel may crack, which may not only damage the exterior of the vehicle but also cause corrosion of the outer panel. there were.

In order to solve this problem, attempts have been made to strengthen the joint by increasing the number of spot welding points or adding a backing reinforcing plate. Due to the increased thermal effect, the distortion of the outer skin of the body increases.Additionally, the method of adding a reinforcing backing plate not only increases the number of work steps, but also
There were drawbacks such as an increase in the size of the vehicle due to the increased amount of materials used.

On the other hand, it is conceivable to bond the two together by interposing an adhesive or the like between the overlapped joints of the outer panels, and to join the overlapped joints by spot welding. With this joining method, the entire overlap joint is joined, and the load is received by the inoculant and the spot weld, increasing the joint strength, and as a result, the bonding strength of the joined skin panels increases. It can prevent movement, prevent and cover cracks in the body sheet and paint, and also reduce distortion of the outer skin and improve the car body shape.
The weight can be reduced.

However, many of the inoculants conventionally known as adhesives for gold, such as structural adhesives, are in the form of a paste and require several tens of minutes to several hours to completely harden. In today's assembly-line vehicle manufacturing process, the outer panels are immediately sent to the next process after being joined, so the inoculant often does not harden sufficiently before being sent to the next process, so the adhesive is simply spot welded. If used in combination with, for example, a degreasing process as a pre-treatment for painting, a strength treatment process, phosphoric acid skin 19! During the treatment process, and even during the coating process with Electron 1 as an undercoat, the bonding properties may scatter or change in quality, and the intended purpose of using the inoculant together, that is, increasing the bonding strength, may not be achieved. If the adhesive flows out or so-called blisters occur, this will cause inconveniences such as the need to reapply the inoculant at the joint before painting.

This kind of inconvenience may be solved by sending the joined product to the next process such as 121 after the adhesive has completely cured, but the curing time of the adhesive depends on other processes as mentioned above. It takes quite a long time compared to the time required for the process, so if you wait for the adhesive to harden before sending it to the next process,
Other problems arise, such as extremely poor productivity.

This invention was made in view of the above circumstances.

When performing spot welding with an adhesive interposed in the lap joints of vehicle exterior panels to be joined, this method does not cause any effects on the joint strength such as scattering or outflow of the circulating agent, or any negative effects during the painting process. The purpose of this method is to provide a method that can join vehicle exterior panels, and its characteristics include interposing an adhesive between the overlapped joints of vehicle exterior panels to be joined, and controlling the state of the adhesive. Spot weld the two with
Thereafter, the exposed portion of the adhesive on the outer surface is covered with an inoculant, and then the outer surface of the vehicle outer panel is painted.

The method of the present invention will be explained in more detail below.

First, the outer panels 1a and 1b to be joined to each other are connected at the outer joint 2.
a and 2b, as shown in FIG. Surface 3a,
3b is formed to be a substantially continuous plane. After applying the inoculant 4 to a substantially uniform thickness on one or both of the facing surfaces of these joint parts 2a and 2b, the lap joint parts 2a and 2b are overlapped with the inoculant 4 interposed therebetween. , After that, spot welding is performed by spot welding l115. Here, as the adhesive 4, it is preferable to use a thermosetting structural adhesive, for example, an epoxy-based adhesive, a phenol-based adhesive, a resorcinol-based adhesive, etc. Since oil may be attached to the surface, it is preferable to use a material that has oil absorption properties (oil surface adhesion).

As described above, the outer panels 1a and 1b are stacked together at the joint 2a.
, 2b, the sliding door glued and welded, the exposed part of the inoculant 4 to the outer surface, that is, the lap joint l! Coating material 6 is applied to the four parts on the tip side of the other outer plate 1b in 12a and 2b.
Fill it. The coating material 6 may be a room-temperature curing adhesive such as an olefin rubber adhesive or a urethane adhesive, or a heat-activated adhesive whose reaction is accelerated by heating.
For example, homogeneous epoxy adhesives, hot melt adhesives, etc. can be used, and in any case, those that have oil surface adhesion and have a faster curing speed than the adhesive 4 described above are preferred. In addition, l! The coating film thickness of 2WI agent 6 is 100 μ to 3
000μ, and the filling method may be a method using a spatula or a caulking gun as long as the coating material 6 has fluidity, but if the coating material 6 is a room-temperature curing sheep and the filling method is as shown in FIG. When it is raised as shown in <A), it is preferable to shape it using a jig 7 called a squeegee, which has a protrusion that slightly enters the recess, as shown in FIG. 8(8). This is to form a gap to be filled with a body seek 9 to be described later, and in this case, the squeegee 7 made of rubber is better in terms of finish.

After filling the coating material 6 as described above, the outer panel 1a.

As shown in FIG. 4, the outer surfaces 3a and 3b of the outer panels 1b are coated with an electric coating 8 as an undercoat to smooth the outer surfaces 3a and 3b of the outer panels 1a and 1b. After that, in order to prevent rust and flatten the edges of the other outer panel 1b, the front two
Body seek 9 is filled into the recesses formed after filling coating material 6. In addition to the above-mentioned purpose, Body Seek 9 is used to improve the adhesion of the intermediate coating*io described below or the top coat mWsil when the intermediate coating is omitted, and therefore improve the appearance finish. If you don't particularly like it, use Body Seek 9.
Alternatively, a room temperature curing type sheep may be used.

After surface-coating and undercoating the joints as described above, the entire outer surface including the joints is coated with an intermediate coat by spray painting or electrostatic coating, and a top coat by spray paint. The bonding is completed by forming the respective coating films 10 and 11 as shown in FIG.

However, in the above-mentioned joining method, there is no possibility of intervening between the overlapping joints 2a and 2b when applying an electric coating as an undercoat, when painting an intermediate coat, or when painting a topcoat, and when removing 11ffi as a pre-161. Adhesive 4
Even if the adhesive 4 is not completely cured, the exposed portions of the outer surfaces 3a and 3b of the adhesive 4 are covered with the coating material 6, so the adhesive 4 will not scatter, leak, or blister. can be prevented.

Next, examples of this invention will be described.

Rear left and right body outer panels for microbuses (thickness 0.
8+es) were bonded under the following conditions.

Joint width: 1211 Number of spot welding points: 3 m points 100 - Adhesive: Liquid epoxy adhesive (manufactured by Sumitomo 3M Ltd.) Coating agent: Solid epoxy adhesive (manufactured by Toagosei Kagaku Ltd. 1) Body sealer; PVC-based thermosetting sealer (manufactured by Nippon Rubber Co., Ltd.) When the exterior of the vehicle was inspected after the joint was completed, the outer surface was flattened and smoothed, and there were large differences in appearance between the joint and other parts. There was no difference. In addition, running tests such as an actual vehicle running durability test on rough roads were carried out after 20,000 years, and no cracks in the coating film or seek were observed even after running.

Second Comparison When the same inspections and tests as those described above were carried out on vehicles joined without using the above-mentioned coating, it was found that there were many cases of insufficient adhesion due to extrusion and scattering of the adhesive.

From the above results, it is clear that according to the joining method of the present invention, la and lb can be joined with high strength without damaging the appearance.

In addition, what is the adhesive 4 in this invention? ll[? IIO2
can be used in combination as appropriate, but the key is IJ! Each type may be selected so that the coating material 6 prevents the adhesive 4 from flowing out or scattering during the mounting process and its pretreatment force treatment process, phosphoric acid film treatment process, and the like.

As is clear from the following description, according to the joining method of the present invention, an adhesive is interposed between the overlapping joints of the vehicle outer panels to be joined, the two are spot welded in that state, and then the adhesive is applied. Since this is a method of covering the exposed part of the agent on the outer surface with a coating agent and then applying the coating to the outer surface of the vehicle exterior panel, it is difficult to apply the force treatment process or the phosphoric acid skin II treatment process that is performed as a TTJ treatment for painting. It is possible to prevent the adhesive from flowing out or scattering during the printing process, or from blistering during the baking process. Therefore, according to the bonding method of the present invention, since the adhesive does not affect the paint film, it is possible to improve the appearance of the vehicle, and at the same time, the adhesive does not leak or scatter. Therefore, the vehicle outer panels can be joined with high strength, and cracks in the paint and seams 5 at the joint can be prevented for a long period of time.

[Brief explanation of the drawing]

The figure is a schematic illustration showing the joining process according to the present invention, 1
Figure 1 shows the adhesion and spot welding process, Figures 2 and 3
Figures (A) and (B) show the coating agent filling process, Figure 4 shows the Den II painting process, Figure 5 shows the body sealer filling process, and Figure 6 shows the intermediate coating and top coating processes. 1a, lb...Vehicle outer plate, 2a, 2b...Overlap joint, 3a, 3b...Outer surface, 4...Work agent, 5...Spot welder, 6...? ! m agent,
8... Electric w coating training, 9... Body sealer, 1
0... Intermediate coating film 1 1 -... -to Coat ta
*0 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) After welding the vehicle exterior panels at multiple points, when joining the vehicle exterior panels by painting the exterior surfaces, an adhesive is interposed between the overlapped joints of the vehicle exterior panels to be joined. Then, the lap joints are spot welded at a plurality of points, and then the exposed portion of the adhesive on the outer surface is covered with a coating material, and then the outer surface of the vehicle outer panel is painted to a certain extent. How to join vehicle outer panels. (2) The method for joining vehicle outer panels according to claim 1, wherein the coating material is a chamber-a curing sealer. (3) The method for joining vehicle outer panels according to claim 1, wherein the coating material is a heat-activated adhesive whose reaction is accelerated by heating.