JPS59167638A - Manufacture of inner box of cooking range - Google Patents

Abstract

PURPOSE:To prevent the raising or exfoliation of the paint coated on the steel plates forming a cooking range by a method wherein the coated steel plates are subjected to a curling process in a heated condition. CONSTITUTION:The front plate 5 of the inner box of a cooking range is made to have a curling allowance 21 along the outer peripheral edge of an opening 7. Likewise, the front edge of the trunk plate 10 is made to have curling allowances 13A, 13B and 13C and the ceiling plate 9 is made to have a curling allowance 18. These plates 5, 10 and 9 are bonded together after they are subjected to a curking process at the curling allowances. In this case, the curling allowance 21 of the front plate 5 is caulked to cover the top end of the curling allowance 13B of the trunk plate 10 and therefore, a considerable degree of strain generates at the most acutely bent section 21A of the plate 5. However, since the above-mentioned plates are subjected to the curling process in a heated condition, there is no possibility of the film of the coated paint becoming raised or exfoliated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an improvement in a method of manufacturing an inner box for a cooking appliance, such as a microwave oven or an oven.

Description of Prior Art Cooking appliances such as microwave ovens and ovens have advantages such as shortening cooking time and maintaining constant heating, so they are widely used for both commercial and domestic purposes. ing.

FIG. 1 is a perspective view schematically showing a typical example of a conventional microwave oven. The microwave oven 1 consists of a main body 2 and a door 3. The main body 2 includes an inner box 4.

In heating cooking appliances such as microwave ovens, an inner box 4 is provided in order to effectively utilize heat and prevent leakage of radio waves.
The main body 2 has a double structure.

FIG. 2 is a perspective view schematically showing this type of inner box.

The inner box 4 includes a front plate 5, a body 6, and a rear plate (not shown). The body part 6 has a cylindrical structure and consists of a top plate 9 and a body plate 10 having a U-shaped cross section. The front plate 5 has an opening 7
is provided.

The opening 7 is formed to take in and take out the food to be cooked. The body 6 and the front plate 5 are joined at the front edge of the body plate 10, the front edge of the top plate 9, and the peripheral edge 7a of the opening 7. Although not shown, the body portion 6 and the rear plate are joined at the rear edge 10b of the body plate 10, the rear edge 9b of the top plate 9, and the outer peripheral edge of the rear plate. Therefore, the inner box 4 has a hexahedral shape as a whole, and is provided with an opening 7 only at the front.

In the inner box 4 having the above structure, the auxiliary plate 5, the body plate 10, the top plate 9, and the rear plate have conventionally been joined by spot welding. This is to ensure the tightness of the inner box 4, prevent leakage of radio waves, and provide a strong structure. However, spot welding has the drawback that it requires a lot of effort to join each part. Furthermore, since spot welding cannot be easily automated, it has been impossible to increase the efficiency of the joining operation. Therefore, it has been desired to develop a method for manufacturing an inner box for a cooking appliance that can achieve high quality bonding.

In order to eliminate the above-mentioned drawbacks of spot welding, it is conceivable to achieve each joint of the front plate, body portion, and rear plate by curling processing. This is because it is easy to automate and can use painted steel plates. FIG. 3 is a perspective view showing an example of an inner box of a cooking appliance joined by a curling process.The inner box 4 is composed of a front plate 5, a body 6, and a rear plate 8. The front plate 5 includes an opening 7. The body part 6 is a top plate 9
and a chest plate 10 having a U-shaped cross section. Therefore, the overall shape is the inner box 4 of the microwave oven shown in Figure 2.
It is similar to

Next, the process of joining the inner box 4 of the cooking appliance shown in FIG. 3 will be explained with reference to FIGS. 4 and 5.

3 curling allowances 11A, 1 on part of the longitudinal sides
18.11G and flange section 12A.

12B is formed, and three curling allowances 13A, 138.13C and a flange portion 1 are formed on the other longitudinal side.
4A and '14B are formed, and one curling margin 15A and 15B are formed on each of the other two sides. A plate-like member made of a painted steel plate is prepared, and then the longitudinal side of the whole becomes U-shaped. By bending it as shown, the body plate 10 is obtained.

On the other hand, a top plate 9 with curling allowances 16, 17, 18° 19 formed on four sides was prepared, and a rear plate 8 was similarly prepared with four curling allowances 20Δ, 20B, 20C, 20D formed on the outer peripheral edge, respectively. Prepare.

a top plate 9 on which each curling mark is formed as described above;
The body plate 10 and the rear plate 8 are assembled in the directions of arrows P and Q in FIG. 4, and then curled.

Further, as for the front plate 5, as shown in the perspective view in FIG. Each car song is 13A.

13B and 130.18 are curled and joined.

In the manner described above, the inner box 4 of the cooking appliance shown in FIG. 3 is obtained. The joining structure for each curling process is disclosed in Utility Model Application No. 1983-70675 filed by the same applicant.

When curling as described above is used, welding work can be automated extremely easily. However, painting! When four plates were used, there was a problem in that the painted part peeled off or floated during processing at the large curved part of the shell where curling or caulking was applied. Therefore, there have been problems such as the appearance of the inner box 4 of the cooking appliance being damaged, and moisture entering through the peeled portions and causing chains. In particular, even if there were no problems during manufacturing, repeated heating and cooling during use caused the paint film to gradually lift or peel.

Therefore, as a method for manufacturing the inner box 4 of the cooking appliance,
Although curling is extremely effective, painted steel sheets could not be used as they were.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing an inner box for cooking appliances, which makes it possible to obtain an inner box for cooking appliances with excellent aesthetic appearance without requiring a complicated painting process.

Briefly speaking, the present invention is a method for manufacturing an inner box for a cooking appliance, which comprises using painted steel plates for at least a portion of the front plate, cylindrical body, and rear plate, and applying a curling process under heating. It is.

Other objects and features of the invention will become clear from the following description of embodiments with reference to the drawings.

DESCRIPTION OF THE EMBODIMENTS As mentioned above, the features of the present invention reside in the use of a painted steel plate and in the curling process under heating. FIG. 6 is a partial sectional view for explaining one embodiment of the present invention, showing a curling margin 13B formed on the front edge of the body plate 10 and a curling margin 21 of the front plate 5.
FIG. In this embodiment, the front plate 5
The curling margin 21 is the curling margin 1 of the body plate 1Q.
It is caulked to wrap around the tip of 3B. Therefore, considerable distortion occurs in the maximum curved portion 21A. As described above, in the conventional curling joint structure, when a painted steel plate is used, there is a problem that the paint peels off or floats at the maximum curved portion 21A. However, in this invention, the curling process is performed "under heating.""Underheating" includes both "processing while heating" and "processing after heating." Moreover, the degree of "heating" is such that the coating film is softened so that it can follow the distortion of the rear plate when processing is performed under heating. This invention is based on the knowledge that the above-described problems associated with the conventional curling process can be solved by performing the curling process "under heating." For other manufacturing processes,
Since this is exactly the same as the joining process of the conventional curling process, detailed explanation thereof will be omitted.

It should be noted that the present invention is applicable not only to the joining structure having the cross-sectional shape shown in FIG. 6 but also to various curling processes. For example, as shown in FIG. 7, a protrusion 51 is formed on one curling seal, and an opening 52 for receiving the protrusion 51 is formed on the other curling seal, thereby ensuring a strong bond. It can also be applied to curling processes that yield the following results.

Furthermore, since painted steel plates are used for "at least a portion of the front plate, cylindrical body, and rear plate," it is possible to use painted steel plates only for the front plate, or for all of them. It is.

Effects of the Invention As described above, according to the present invention, painted steel plates are used for at least a portion of the front plate, the cylindrical body, and the rear plate, and the curling process is performed under heating, so that no additional painting work is required. It is possible to obtain the inner box of the oak cooking utensil which has an attractive appearance without the need for additional steps. In particular, since the curling process is performed "under heat", it is possible to effectively prevent the lifting or peeling of the paint, which has been a problem in the past.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an electronic cooker 2 as an example of cooking equipment. FIG. 2 is a perspective view schematically showing the inner box of the cooking appliance. FIG. 3 is a partially cutaway perspective view showing the inner box of the cooking rack joined by curling. FIG. 4 is a perspective view showing a process of joining the inner box of the cooking appliance shown in FIG. 3. FIG. 5 is a perspective view of the front plate of the inner box of the cooking appliance shown in FIG. 3, viewed from the rear. FIG. 6 is a partial sectional view for explaining one embodiment of the present invention. FIG. 7 is a partial sectional view showing another example of a joint structure of an inner box of a cooking appliance to which the present invention can be applied. In the figure, 4 is an inner box, 5 is a front plate, 6 is a body, and 8 is a rear plate. 5th [So1 6th residence

Claims (1)

[Scope of Claims] A method for manufacturing an inner box for a cooking appliance, comprising a front plate, a cylindrical body, and a rear plate having a gateway, and the front plate, the cylindrical body, and the rear plate are joined by curling. A method for manufacturing an inner box for a cooking appliance, characterized in that at least a portion of the front plate, the cylindrical body, and the rear plate are made of painted steel and subjected to a curling process under heating.