JPS6045968B2 - Curling joint structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joining structure for curling, and in particular,
A metal member having a cylindrical or U-shaped cross section and a metal plate having an area larger than the opening area of the metal member are joined by a curling process.

This paper relates to a joining structure for curling processing. FIGS. 1 and 2 are schematic perspective views for explaining an inner box of a microwave oven, which is an inner box of a cooking appliance that gave rise to the present invention. The microwave oven 1 consists of a main body 2 and a door 3. The main body 2 includes an inner box 4. In a heating cooker such as a microwave oven, an inner box 4 is provided in order to effectively utilize heat and prevent radio wave leakage, and the main body 2 has a double structure. As is clear from FIG. 2, the inner box 4 includes a front plate 5,
It is composed of a body part 6 and a rear plate 7.

By the way, the rear plate 7 of the inner box 4 is connected to the rear plate of the main body 2 (not shown).
Efforts are being made to make them common. That is, J 1st
An attempt has been made to make the rear plate of the microwave oven 1 shown in the figure common to the rear plate 7 of the inner box 4 so that the rear plate of the microwave oven 1 has a single layer structure. This was done to reduce the overall thickness of the microwave oven and make it more compact. However, when manufacturing the inner box 4, the body 6 and the rear plate 7 had to be joined by spot welding. This is because the opening area of the body portion 6 of the rear plate 7 is larger than that of the rear plate 7, and therefore the normal curling process which is advantageously used for joining metal plates cannot be performed. In this way, when manufacturing the inner box 4 shown in FIG. 2, the body 6 and the rear plate 7 were joined by spot welding, which made the joining work extremely complicated and a major factor in increasing the cost of the product. I was getting used to it. Of course, even when spot welding is used, it is possible to automate it by using processing equipment such as a dedicated robot, but using a dedicated machine such as a robot itself greatly increases the product cost. On the other hand, when joining the body part 6 and the rear plate 7 in the inner box 4 as shown in FIG.
It is also conceivable to use caulking, which has been widely practiced in the past.

However, caulking simply fixes metal plates, and the joint strength is extremely weak.
It cannot be used for this type of inner box 4 at all.
Therefore, the main object of the present invention is to provide a curling joint in which a metal member having a cylindrical or U-shaped cross section and a metal plate having an area larger than the opening area of the metal member are joined by a force ring process. It's about providing structure.

In summary, the present invention provides a curling joint structure in which a metal member having a cylindrical or U-shaped cross section and a metal plate having an area larger than the opening area of the metal member are joined by curling. In this case, a bent portion is formed perpendicularly outward from the main surface at the opening edge or U-shaped edge of a cylindrical or U-shaped metal member in cross section. A plurality of first locking pieces extending in the direction of the metal plates to be joined are formed at the tip of the part, and a plurality of openings for receiving the first locking pieces are formed in the metal plate by cutting and bending. A part of the metal plate raised by this cutting and raising is extended in the opposite direction to the cylindrical or U-shaped metal member in cross section to form a second locking piece. This is a joining structure using a curling process, in which a first locking piece and a second locking piece are overlapped and joined by a curling process.

Other objects and features of the invention will become apparent from the detailed description of the invention with reference to the drawings.

FIG. 3 is a perspective view showing an inner box of a microwave oven as an inner box of a cooking appliance to which an embodiment of the present invention is advantageously applied.

The inner box 4 is formed by curling at each joint. That is, the front plate 5 and the body plate 10, the front plate 5 and the top plate 9, the body plate 10 and the rear plate 7, and the top plate 9 and the rear plate 7 are all joined by curling. Among these, in particular, the structure of each joint between the cylindrical body 6 composed of the body plate 10 and the top plate 9 and the rear plate 7 is a feature of the present invention, as will be described later. configuration has been adopted. Figure 4 shows the first joints forming each joint shown in Figure 3.
It is a perspective view showing the process.

The body plate 10 has three curling grooves 11 on one of the longitudinal sides of the plate made of a metal material such as stainless steel.
A, 11B, 11C and flange parts 12A, 12B
and three curling margins 13A, 13B, 13C and flange portions 14A, 1 on the other longitudinal side.
4B, one curling margin 15A, 15B is formed on each of the other two sides, and then the entire board is bent so that the longitudinal sides become U-shaped.
Curling margins 16, 17, 18, and 19 are formed on the outer peripheral edges of the top plate 9, respectively. By the way, the detailed structure of the curling margins 11A, 11B, 11C, and 16 that constitute the joining structure of the curling process, which is a feature of the present invention, will be explained later. A plurality of openings 20 are formed in the rear plate 7 by cutting and raising, and a part of the rear plate 7 raised by cutting and raising is formed in the body plate 1 to be joined.
0 and the direction opposite to the direction of the top plate 9 to form a second locking plate 21. The top plate 9, body plate 10, and rear plate 7, each having a curling margin formed in this way, are joined as follows.

First, the top plate 9 is assembled to the body plate 10 in the direction of arrow P in FIG. Next, the curling allowance 17 of the top plate 9, the curling allowance 15B of the body plate, and the curling allowance 1 of the top plate.
9 and the curling margin 15A of the body plate are respectively joined by curling processing. As a result, the top plate 9 and the body plate 10 form a cylindrical body portion 6. The curling process performed when joining the top plate 9 and the body plate 10 is
This can be advantageously carried out by the apparatus and method disclosed in JP-A-55-54230'', JP-A-55-54231 and JP-A-55-54221 by the same applicant. The joining structure between the top plate 9, the body plate 10, and the rear plate 7, which is a feature of the above, will be explained.

As is clear from FIG. 4, on the rear edge of the body plate 10,
Curling margins 11A, 11B, and 11C are formed. Each curling margin 11A, 11B, 11C is formed with a bent portion 111A, 111B, 111C that is vertically bent outward from the main surface of the cylindrical body plate 10. A plurality of first locking pieces 31A, 31B, and 31C are formed at the tip end and extend in the direction of the rear plate 7 to be joined. As is clear from FIG. 4, the tips of the first locking pieces 31A, 31B, and 31C are slightly bent inward. Similarly, in the curling margin 16 at the rear edge of the top plate 9, a bent portion 116 is formed which is vertically bent outward from the main surface of the top plate 9, and this bent portion 1
A plurality of first locking pieces 32 extending in the direction of the rear plate 7 to be joined are formed at the tip of the first locking piece 16 . First locking piece 3
The tip of 2 is also slightly bent inward or downward. As mentioned above, a plurality of openings 20 are formed in the rear plate 7 by cutting and bending, and these openings 20 are connected to the first locks formed at the opening edges of the top plate 9 and the body plate 10. It is provided to receive the pieces 31A, 31B, 31C, and 32.

That is, the first locking pieces 31A, 31B, 31C, 32 close the opening 2 when the rear plate 7 comes into contact with the top plate 9 and the body plate 10.
0, and is overlapped with the second locking piece 21.
This state will be explained using partially enlarged sectional views of FIGS. 5 to 7. Referring to FIG. 5, the first locking piece 32 of the top plate 9
In contrast, the opening 20 of the rear plate 7 is moved closer in the direction of arrow R. When the bent portion 116 of the top plate 9 comes into contact with the main surface of the rear plate 7, as shown in FIG.
The locking pieces 21 are overlapped with each other. In this state, curling is performed by abutting a mold from the direction of arrow S in FIG. The state in which the curling process has been performed is shown in a partial sectional view in FIG. The above explanation was about joining the top plate 9 and the rear plate 7, but the connection between the body plate 10 and the rear plate 7
The same applies to joining with. FIG. 8 shows a rear view of the inner box 4 joined by the curling process as described above. Figure 8? As is clear from these figures, in the inner box 4, the body portion made up of the top plate 9 and the body plate 10 and the rear plate 7 are joined at 16 points. The relationship between the body portion 6, that is, the top plate 9 and the body plate 10, and the rear plate 7 after being joined is shown in a partial cross-sectional view taken along the line ■-■ in FIG. As is clear from FIG. 9, according to the characteristic joint structure of the present invention, the main surfaces of the top plate 9 and the body plate 10 and the rear plate 7 are in contact with each other in the curling joint structure. It will be appreciated that the interior of the inner box 4 can be reliably sealed since it is located outside of the inner box 4. That is, the presence of the bent portions 116 and 111B ensures the sealing performance of the inner box 4. FIG. 10 is a partially enlarged sectional view showing a second embodiment of the invention, and corresponds to FIG. 7.

In the second embodiment, a protrusion 21a is formed at the tip of the second locking piece 21 of the rear plate 7 by punching or the like. After the curling process is performed, as is clear from FIG. 10, the protruding portion 21a bites into the second locking piece, thereby making the joint structure of the curling process even stronger. That is, the locking piece 21a can effectively prevent the rear plate 7 and the top plate 9 from shifting in the direction perpendicular to the plane of the drawing. Similarly, in the third embodiment of the present invention shown in FIG. The first locking piece 31B
A cut and raised piece 311B is formed at the tip. After the curling process is performed, as is clear from FIG. 11, the cut and raised piece 311B is fitted into the slit 21b. Therefore, similarly to the second embodiment shown in FIG. 10, in the third embodiment as well, it is possible to make the bonding strength extremely large in the direction perpendicular to the plane of the paper. In particular, compared to the width of the opening 20, the first locking piece 31A
, 31B, and 31C, the second and third embodiments are effective because they tend to shift in the direction perpendicular to the plane of the paper. Note that the protrusion 21a1 slit 21b1 cut and raised piece 31 shown in FIGS. 10 and 11
It should be pointed out that 1B may be formed on either side of the first locking piece and the second locking piece.

Next, the connection between the front plate 5, the top plate 9, and the body plate 10 will be explained with reference to FIGS. 3 and 12. The front plate 5 is provided with an opening 5a. The opening 5a is formed to take in and take out the food to be cooked. Nine locking pieces 201 are formed on the peripheral edge 5b of this opening 5a.
Moreover, as mentioned above, as is clear from FIG.
, 13C are formed. Each curling space 13A,
Three slits 200 are formed in each of 13B and 13C. Similarly, three slits 200 are formed in the curling margin 18 at the front edge of the top plate 9. Note that the joint structure between the front plate 5 and the top plate 9 is similar to that of the front plate 5.
The joining structure between the front plate 5 and the body plate 10 is the same as that of the front plate 5 and the body plate 10. Therefore, the following description will mainly focus on the joint structure between the front plate 5 and the body plate 10. Figure 13 shows the 12th
This is a partially cutaway perspective view showing an enlarged portion indicated by x in the figure.

FIG. 14 is a partially cutaway sectional view showing the joining process between the front plate 5 and the body plate 10, and FIG. 15 is a partially cutaway sectional view showing the joining structure between the front plate 5 and the body plate 10. . As is clear from FIGS. 13 and 14, a bent portion 203 formed by bending backward from the main surface 202 is provided on the peripheral edge 5b of the opening 5a of the front plate 5. Bending part 20
3, a locking piece 201 whose tip is directed inward, that is, toward the main surface 202, is formed by cutting and raising. On the other hand, as is clear from FIGS. 4 and 14, the front edge of the body plate 10 is provided with a bent portion 206 that is bent forward from the edge 205 of the first projecting portion 204. . A slit 200 is provided in a part of the bent portion 206. The shape of the slit 200 is based on the shape of the front plate 5.
A locking piece 201 provided on a bent portion 203 of the holder is adapted to be received. The front plate 5 and body plate 10 that have been processed as described above are shown in the arrows C and D in FIG.
When they are overlapped in the direction shown and curled, a joined structure of the curling process as shown in FIG. 15 is obtained. As is clear from FIG. 15, the tip of the locking piece 201 provided on the bent portion 203 of the front plate 5
The slit 200 is opposed to and in contact with one end surface 200a of the slit 200 provided therein. Therefore, in the embodiment shown in FIG. 15, even if the front plate 5 and the body plate 10 are pulled or pushed in either direction of the arrows X and -X in FIG. Never. Therefore, the bonding structure shown in FIG. 15 has extremely high bonding strength. 16th
The figure is a partially cutaway sectional view showing a joint structure of the corner portion of the peripheral edge 5b of the opening 5a of the front plate 5 with the body plate 10.

As is clear from FIG. 16, in the coat part, the body plate 1
The flange portions 13A and 13B of 0 are bent portions 203 as curling allowances for the front plate 5 (see FIG. 12).
press against. Therefore, as is clear from FIG. 16, although the curling process is not performed, the bent portion 203 and the flange portion 14A are both strongly pressed together by the action of the spring. Therefore, the front plate 5 and the body plate 10 have sufficient adhesion even at the corner portion of the peripheral edge 5b of the opening 5a. As described above, the front plate 5 and the body plate 10 are firmly achieved by the structure disclosed in Japanese Patent Application No. 56-93566 by the same applicant.

Further, the front plate 5 and the top plate 9 are also joined by the same curling process. As described above, according to this invention,
A bent portion that is vertically bent outward from the main surface is formed on the opening edge or U-shaped edge of a cylindrical or U-shaped metal member in cross section. A plurality of first locking pieces extending in the direction of the metal plates to be joined are formed at the tip, and a plurality of openings for receiving the first locking pieces are formed in the metal plate by cutting and bending. A part of the metal plate raised by this cutting and raising is extended in the opposite direction to the cylindrical or U-shaped metal member in cross section to be joined to form a second locking piece, Since the first locking piece and the second locking piece are overlapped and joined by a curling process, the metal member has a cylindrical or U-shaped cross section and an area larger than the opening area of the metal member. can be joined by curling process. Therefore, complicated work such as spot welding, which was indispensable in the past, can be omitted, and since it is a type of curling process, it can be easily automated, thus reducing the cost of the product. This makes it possible to reduce the

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a microwave oven as a cooking device that gave rise to the invention. 2 is a schematic perspective view showing the inner box of the microwave oven of FIG. 1. FIG. FIG. 3 is a partially cutaway perspective view showing an inner box of a cooking appliance to which an embodiment of the present invention is advantageously applied.
FIG. 4 is a perspective view showing the first step of forming each joint shown in FIG. 3. 5 to 7 are partially cutaway sectional views showing a first embodiment of the present invention.
FIG. 8 is a rear view of the inner box 4 shown in FIG. 3. 9th
The figure is a sectional view taken along the line ■-■ in FIG. FIG. 10 is a partially cutaway sectional view showing a second embodiment of the invention, and corresponds to FIG. 7. FIG. 11 is a partially cutaway sectional view showing a third embodiment of the present invention, and corresponds to FIG. 7. FIG. 12 is a partially cutaway perspective view showing the front plate. FIG. 13 is a partially cutaway perspective view enlarging the portion indicated by X-- in FIG. 12.
FIGS. 14 and 15 are partially cutaway sectional views for explaining the connection structure between the front plate and the body plate. Figure 16 shows
FIG. 4 is a partially cutaway sectional view showing a joint at a corner portion of the opening of the front plate of the inner box shown in FIG. 3; In the figure, 6
7 is a rear plate as a metal plate, 9 is a top plate that constitutes the body, 10 is a body plate that constitutes the body, 20 is an opening, and 21 is a second engagement plate. Stopper, 31A, 31B
, 31C, 32 are first locking pieces, 111A, 111B,
111C and 116 indicate bent portions.

Claims (1)

[Claims] 1. A metal member having a cylindrical or U-shaped cross section and a metal plate having an area larger than the opening area of the metal member,
In a curling joint structure formed by curling, the opening edge or U-shaped edge of the cylindrical or U-shaped metal member in cross section is bent perpendicularly outward from the main surface. A bent part is formed,
A plurality of first locking pieces extending in the direction of the metal plates to be joined are formed at the tip of the bent portion, and the metal plate has a plurality of openings for receiving the first locking pieces. is formed by cutting and bending, and a part of the metal plate raised by cutting and bending is extended in the opposite direction to the cylindrical or U-shaped metal member in cross section to be joined to form a second locking piece. A curling joining structure in which the first locking piece and the second locking piece are overlapped and joined by curling.