JPS5941444Y2 - Inner box of cooking equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an inner box for a cooking appliance, and more particularly to an inner box for a cooking appliance such as a microwave oven or an oven with improved joints.

BACKGROUND ART Cooking appliances such as microwave ovens and ovens have advantages such as shortening cooking time and ensuring constant heating, and are therefore widely used for both commercial and home purposes.

FIG. 1 is a perspective view schematically showing a typical example of a conventional microwave oven.9 A microwave oven 1 consists of a main body 2 and a door 3. As shown in FIG.

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 an inner box that has been used conventionally.

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 is provided with an opening 7.

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 10a of the body plate 10, the front edge 9a 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 10bb 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.

Also, since the body 6 is joined to the peripheral edge 7a of the opening 7 of the front plate 5, the outer portion 5a of the front plate 5 outside the opening 7 has a shape that protrudes from the front surface of the body 6 vertically and horizontally. It is said that

The outer portion 5a of the front plate 5 is an essential portion for fixing the inner box 4 to the main body 2.

In the inner box 4 of the conventional microwave oven 1 configured as described above, each joint of the front plate 5, body plate 10, top plate 9, and rear plate is as follows.
It is done 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 disadvantage that it requires a great deal of effort to join each part.

Furthermore, since spot welding cannot be easily automated, it is also impossible to increase the efficiency of the joining operation.

Therefore, it has been desired to develop an inner box with a structure that allows for highly efficient bonding.

Furthermore, when joining by spot welding, painting must be done after spot welding, which also reduces work efficiency.

Therefore, the main purpose of this invention is to eliminate the above-mentioned drawbacks and to provide an inner box with a structure that allows for highly efficient joining.

In summary, this invention includes a front plate having an opening, a cylindrical body formed by joining a top plate and a body plate having a U-shaped cross section, and a rear plate, and the periphery of the opening in the front plate. In an inner box of a cooking appliance in which the front edge of the body is joined to the front edge of the body, and the rear edge of the body is joined to the outer peripheral edge of the rear plate, each joint is made so that both edges to be joined are This inner box for cooking equipment is characterized by being made by a curling process.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 3 is a partially cutaway perspective view showing an inner box of a microwave oven as an embodiment of the invention.

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 6 is composed of a top plate 9 and a body plate 10 having a U-shaped cross section.

Therefore, the overall shape is the same as the inner box 4 of the conventional microwave oven shown in FIG.

A feature of the inner box 4 of this embodiment is that each joint is formed by curling.

That is, the front plate 5 and the body plate 10, the front plate 5 and the top plate 9, and the body plate 1.
0 and the rear plate 8 and the top plate 9 and the rear plate 8 are all joined by curling.

Note that the connections between the body plate 10 and the top plate 9, the body plate 10 and the rear plate 8, and the top plate 9 and the rear plate 8 are all made according to Japanese Patent Application Laid-open Nos. 55-54230, 1982-54231, and 1983, which were made by the same applicant. It should be pointed out that the curling process can be performed by the apparatus and method disclosed in No. 55-54221.

Furthermore, the joints between the front plate 5 and the top plate 9 and between the front plate 5 and the body plate 10 are shaped by a completely new type of curling process, as will be described later.

4 to 8B are illustrative views for explaining the joining process and joining structure of the inner box 4 of the embodiment shown in FIG. 3. FIG.

FIG. 4 is a perspective view showing the first step of joining the inner box 4 of this embodiment.

The body plate 10 has three curling grooves II on one of the longitudinal sides of the plate made of a metal material such as stainless steel.
A. IIB.

11C and flange portions 12A, 12B,
There are three curling allowances 13A on the other longitudinal side.

13B, 13G and flange parts 14A, 14B
shape, with I curling margins of 15A on each of the other two sides.
.

15B, and then bending the entire iron plate 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.

The rear plate 8 has curling allowances 20A, 20B, 20
C and 20D are formed on the outer peripheral edges, respectively.

The top plate 9, body plate 10, and rear plate 8 each having a curling shape as described above are joined as follows.

First, the top plate 9 is assembled to the body plate 10 in the direction of arrow X in FIG.

Next, the curling margin 17 of the top plate, the curling margin 15B of the body plate, and the curling margin 19 of the top plate and the curling margin 15A of the body plate are respectively joined by curling processing.

After the top plate 9 is joined to the body plate 10 by curling, the rear plate 8 is assembled to the body plate 10 from the direction of arrow Y in FIG.

Next, the curling allowance 11A of the body plate 10, the curling allowance 20B of the rear plate 8, the curling allowance 11B of the body plate 10, the curling allowance 20C of the rear plate 8, the curling allowance 11C of the body plate 10, the curling allowance 20D of the rear plate 8, and the top Board 9
Curling allowance of 16 and curling allowance of rear plate 8 of 20A
are joined by curling process.

As described above, by performing the curling process at six locations, the top plate 9, the body plate 10, and the rear plate 8 are each firmly joined.

As mentioned above, these curling processes can be advantageously carried out by the apparatus and method disclosed in Japanese Patent Laid-Open Nos. 55-54230, 1982-54231 and 1982-54221 by the same applicant.

These six curling processes each show the same joining structure and differ only in positional relationship.

Therefore, only the joint portion between the top plate 9 and the rear plate 8 will be representatively explained.

The curling margin 16 of the top plate 9 is a first portion bent and extended from the rear edge 9b of the top plate 9 at right angles to the top plate 9.
The overhanging portion 16a, the second overhanging portion 16b bent at a right angle at the tip of the first overhanging portion 16a and extending parallel to the main surface of the top plate 9, and the tip of the second overhanging portion It is composed of a third projecting portion 16c bent diagonally downward.

The curling margin 20A of the rear plate 20, which forms a curling portion together with the curling margin 16 of the top plate 9, is constituted by an overhanging portion extending rearward at right angles to the main surface of the rear plate 8 above the rear plate 8. be done.

When the rear plate 8 is brought into contact with the body plate 10 and the top plate 9, the second projecting portion 16b of the curling margin 16 and the curling margin 20A are positioned so as to overlap.

After that, a support member is brought into contact with the front surface of the first overhanging portion 16a of the curling margin 16, that is, the opposite side to the second overhanging portion 16b, and a curling mold is pressed against the front side of the first overhanging portion 16a, that is, from the side of the rear plate 8, thereby performing curling. Perform processing.

The state of this curling process is shown in FIG.

5 and 6 are diagrams for explaining the connection between the front plate 5, the body plate 10, and the top plate 9, and FIG. 5 shows the front plate 5.
FIG. 6 is a partially cutaway sectional view showing the positional relationship between the opening of the front plate 5 and the body plate 10, and FIG. FIGS. 8A and 8B are partial cross-sectional views showing the joint between the body plate 10 and the front plate 5 at the corner of the opening 7. FIG.

As is clear from FIG. 5, the front plate 5 is provided with an opening 7.

A curling margin 21 is formed around the entire circumference of the peripheral edge 7a of the opening 7 for joining with the body plate 10 and the top plate 9.

The shape of this curling margin 21 is indicated by the cutaway end face 22.

That is, as shown in FIG.
is a first projecting portion 22a extending forward from the front plate 5;
It is composed of a second projecting portion 22b bent from the tip of the first projecting portion 22a toward the inside of the opening, and a third projecting portion 22c bent backward from the second projecting portion 22b.

The angle between the front plate 5 and the first overhanging portion 22a and the angle between the first overhanging portion 22a and the second overhanging portion 22b are each about 90°.

Further, the angle between the second overhanging portion 22b and the third overhanging portion 22c is selected to be about 45° to 60°.

On the other hand, a curling margin 18 is formed on the front edge 9a of the top plate 9, which is joined to the peripheral edge 7a of the opening 7 of the front plate 5, as shown in FIG.

As is clear from FIG. 6, the curling margin 18 includes a first overhanging portion 18a extending upward from the top plate 9 at an angle of about 90° to 120°, and a first overhanging portion 18a.
and a second protruding portion 18b bent at an angle of about 45° to 60° from the tip of the second protruding portion 18b.

Further, as is clear from FIG. 4, on the front edge 10a of the body plate 10 that is joined to the opening 7 of the front plate 5, curling margins 13A, 13B, and 13G are formed as straight portions, and a flange portion 14A is formed. , 14B is formed on a part of the corner.

The curling margins 13A, 13B, and 13C have the same shape as the curling margin 18 formed on the top plate.

As is clear from FIG. 6, the curling margin 22 of the opening 7 and the curling margin 18 of the top plate 9 are connected so that the tip of the second overhanging portion 18b of the curling margin 18 is connected to the third extension of the curling margin 22. Since it is selected to fit inside the protruding portion 22c, this is achieved by pressing the second protruding portion of the curling margin 22 after the front plate 5 contacts the top plate 9 from the front. .

The same applies to the connection between the front plate 5 and the body plate 10.

The reason why such a specific type of curling process is performed when joining the front plate 5 to the top plate 9 and the body plate 10 is that the joining of the front plate 5 is the same as that of the body plate 10 and the top plate 9. This is because so-called normal curling processing cannot be performed because it is performed later.

The structure of the joint between the opening 7 of the front plate 5 and the top plate 9 and the body plate 10 is not the same throughout the peripheral edge 7a of the opening 7.

That is, in the straight portion of the peripheral edge 7a of the opening 7, the seventh
As is clear from the figure, the curling process has been achieved, whereas at a corner portion of the peripheral edge 7a, as is clear from FIG. The flange portion 14A is pressed into contact with the flange portion 14A.

Therefore, the front plate 5 and the body plate 10 are firmly fixed in the curled straight portion.

In particular, in this type of curling process, since the curling margin 22 of the front plate 5 has the first projecting portion 22a, an arc-shaped portion d is formed after joining.

Therefore, the front plate 5 and the body plate 10 are firmly fixed without any fear of coming off even if force is applied in the vertical direction in FIG. 7.

Furthermore, the presence of the portion d dramatically increases the degree of pressure contact at the joint portion.

This is because the front plate 5 and the body plate 10 are made of metal materials, and therefore have a force that tends to return to the original shape after being curled.

This is what is called springback.

Therefore, the joint may become loose as the pressed metal attempts to return.

However, if the portion d exists in the curled joint, the curling margin 13B between the portion d and the body plate 10
This springback causes them to be strongly pressed against each other, and the hermeticity of the joint is sufficiently ensured.

Therefore, prevention of radio wave leakage, which is important in microwave ovens, is completely achieved.

On the other hand, at a portion of the corner of the peripheral edge 7a of the opening 7, the flange portions 13A and 13B of the body plate 10 are curled.
2.

Therefore, as is clear from FIG. 8A, although the curling process is not performed, the tip of the curling margin 22 and
The flange portion 14A is strongly pressed together due to the action of springback.

Therefore, the front plate 5 and the body plate 10 have sufficient adhesion even at a corner portion of the peripheral edge 7a of the opening 7.

It should be noted that the joining at a portion of the corner can be achieved to a distant extent without providing a flange portion projecting to the side of the body plate 10, as shown in FIG. 8B.

That is, the curling margin 22 on the front plate 5 side and the body plate 10
The planar flange portion 13A on the side is pressed and joined.

In this case as well, the curling margin 22 is strongly pressed by the springback action, just as in the case of the structure shown in FIG. 8A.

As described above, the front plate 5 and the body plate 10 are joined by a new type of curling process that is strong and highly airtight.

The front plate 5 and the top plate 9 are also joined by the same curling process.

In addition, as shown in FIG. 7 and FIG. 8A,
Curling allowance 13B and flange 14A of body plate 10
is formed below the body plate 10 at a constant distance C.

Therefore, the curling margin 13B and the flange 14A are designed so that a new plane 24 is formed on the front surface of the peripheral edge 7a of the opening 7 after joining. Easy to insert the inner box 4
This is so that it can be removed from within.

As described above, the inner box 4 for a cooking appliance as an embodiment of this invention is manufactured, but the inner box 4 of this invention is not limited to that shown in FIG. 3.

For example, although each curling portion is illustrated relatively large in FIG. 3, it is also possible to make it smaller;
Therefore, it is also possible to hide the joint between the top plate 9 and the body plate 10 behind the front plate 5 when viewed from the front.

In addition, in the embodiment shown in FIG. 3, the body part 6 was composed of a top plate 9 and a body plate 10, but the body part 6 was formed by rolling a single flat plate into a closed shape, joining both edges to each other, and The cylinder may have various shapes such as a circle or a quadrilateral.

In this case, it goes without saying that the opening of the front plate 5 corresponds to the cross-sectional shape of the cylinder.

Furthermore, the joint portion along the longitudinal direction of the tube that is formed to construct the tube may be located at any position relative to the front plate when constructing the inner box.

Note that FIGS. 9 and 10 are partially cutaway sectional views showing other examples of joining the front plate 5 and the body plate 10.

9 corresponds to FIG. 6, and FIG. 10 corresponds to FIG. 7.

As is clear from FIG. 9, the curling margin 22 on the front plate 5 side is the same as that shown in FIG.

The feature of this example is the curling margin 13B on the body plate 10 side.

Although the curling margin 18 of the top plate 10 is shown in FIG. 6, it has already been stated that the curling margin 13B of the body plate 10 also has the same structure.

On the other hand, the curling margin 13B shown in FIG.
is a first bent portion 13B1 bent outward from the body plate 10 at an angle of about 90° to 120°, a second bent portion 13B2 bent forward from its tip, and a second bent portion 13B2 bent outward from the body plate 10 at an angle of approximately 90° to 120°. A first overhanging portion 13Ba that overhangs outward at an angle of about 90° to 120°, and a second overhanging portion 13Bb that is folded back from the tip of the first overhanging portion 13Ba.
It consists of

The length of the second projecting portion 13Bb is selected to such an extent that it can fit into the curling margin 22 on the front plate 5 side.

As is clear from FIG. 10, the curling margin 13B in this example has substantially the same function as the curling margin 13B shown in FIG.

That is, since the curling margins 22 are the same, after joining, an arcuate portion d is formed and firmly fixed.

Further, in each embodiment of this invention, angles are designated to explain the shape of each curling mark, but it is not necessary to be limited to the above-mentioned angles in order to further achieve the purpose of this invention.

In other words, within the range where curling processing is possible,
Any suitable angle of curling mark may be selected.

As described above, this invention includes a front plate having an opening, a cylindrical body formed by joining a top plate and a body plate having a U-shaped cross section, and a rear plate. In an inner box of a cooking appliance in which the peripheral edge of the opening and the front edge of the body are joined, and the rear edge of the body and the outer peripheral edge of the rear plate are joined, each joint is connected to both sides to be joined. Since this is done by a curling process in which the edges of the paper are rolled together, the entire assembly process can be easily automated, thus making it possible to dramatically improve checkout efficiency.

Furthermore, since spot welding is not used at all in all joint parts, it is possible to reliably prevent leakage of radio waves, and it is also possible to paint before joining, so that painted steel plates can also be used.

Therefore, it is possible to eliminate the complicated painting work of the inner box of cooking appliances, which was conventionally assembled using spot welding.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a microwave oven as an example of a cooking appliance. FIG. 2 is a perspective view schematically showing an inner box of a conventional cooking appliance. FIG. 3 is a partially cutaway perspective view showing an inner box of a cooking appliance as an embodiment of the invention. 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 shows the positional relationship of the joint between the front plate and the top plate. FIG. 7 is a partially sectional perspective view showing the joining structure between the front plate and the body plate. FIG. 8A is a partial cross-sectional perspective view showing a joining structure between the front plate and the body plate at a corner portion of the peripheral edge of the opening. FIG. 8B is a partial sectional view showing another example of the joining structure shown in FIG. 8A. FIG. 9 is a partially cutaway sectional view showing another example of the curling mark on the body plate. FIG. 10 is a partially sectional perspective view showing a joint structure between a body plate and a front plate in which the curling mark of FIG. 9 is adopted. In the figure, 4 is an inner box, 5 is a front plate, 6 is a body, 7 is an opening, 7a is a peripheral edge of the opening, 8 is a rear plate, 8a is an outer peripheral edge of the rear plate, 9 is a top plate, 10 is a body plate, 10a is a front edge of the body plate, and 10b is a rear edge of the body plate.

Claims (1)

[Claims for Utility Model Registration] A front plate having an opening, a cylindrical body formed by joining a top plate and a body plate having a U-shaped cross section, and a rear plate, the opening of the front plate. In an inner box of a cooking appliance in which a peripheral edge of the body and a front edge of the body are joined, and a rear edge of the body and an outer peripheral edge of the rear plate are joined, each of the joints should be joined. An inner box for cooking equipment characterized by a curling process in which both edges are rolled together.