JPH033861B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to the construction of an inner box for a cooking appliance, such as a microwave or oven, with improved joints.

Description of Prior Art FIG. 1 is an external perspective view showing an example of a microwave oven to which the present invention is applied. Microwave oven 1 is
It 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.
is said to have a double structure.

FIG. 12 is a sectional view of a conventional joint between an outer box and an inner box.

In the figure, 100 is an outer box, and 4 is an inner box.
A rear plate 101 of the outer box is arranged at the rear end of the inner box 4. A bent piece 101a is provided on the periphery of the rear plate 101 of the outer box so as to extend forward. The rear plate 101 of the outer box and the inner box 4 are fixed by screws 102 or caulking. The bent piece 101a and the outer box 100 are connected by screws 103.
Fixed by Although not shown, the front end of the inner box is provided with the corresponding front plate of the outer box, and is joined in the same way.

Conventionally, the structure of the joint between the outer box and the inner box was constructed as described above, but if the inner box 4 as shown in FIG. 2 could be realized, the rear plate 101 of the outer box
(See Figure 12) is no longer necessary, and it is expected that the number of parts will be reduced.

Referring to FIG. 2, the inner box 4 is composed of a front plate 5, a cylindrical body 6, and a rear plate 7. Torso 6
is composed of a top plate 8 and a body part 9 having a U-shaped cross section, one end of which is joined to the opening 10 of the front plate 5, and the other end joined to the rear plate 7. In the inner box 4 shown in FIG. 2, bent pieces 5a and 7a are formed on the front plate 5 and the rear plate 7, respectively, which are bent in the direction of the body 6 from the respective main surfaces. bent piece 5a,
7a is an essential structure to provide strength to the inner box 4, and by providing these bent pieces 5a, 7a, the front plate 5 and the rear plate 7 can be assembled into the microwave oven body shown in FIG. It can also serve as the front plate and rear plate of the outer box of No. 2. The reason why the front plate 5 and the rear plate 7 are configured to have a larger area than the opening of the body 6 is to arrange various parts etc. around the cylindrical body 6.

By the way, in the inner box 4 shown in FIG.
Also, since the rear plate 7 serves as both the front plate and the rear plate of the outer box, there is an advantage that the number of parts can be reduced. However, in the conventional inner box 4 of this type, the front plate 5, body 6, and rear plate 7 are joined by spot welding, riveting, or
Or, it was done by fixing with screws, etc. Therefore, there was a problem that the joining work was complicated and the cost of the inner box 4 was high as a result. In particular, when using spot welding, the parts to be welded must not be painted, so it is not possible to join using painted steel plates, and therefore the complicated painting work must be performed again after joining. However, there was a problem in that they were forced to perform even more complicated work.

Therefore, an inner box for a cooking appliance has been proposed in which a front plate, a rear plate, and a body are joined by a curling process. FIG. 3 is a schematic partially cutaway perspective view showing an example of an inner box of a cooking appliance joined by curling. Here, the front plate 5,
The body portion 6 and the rear plate 7 are joined together by curling. In the inner box 4 shown in FIG. 3, as shown in an exploded perspective view in FIG.
For example, three curling margins 11A, 11B, 11C and a flange portion 12 are provided on one longitudinal side of a plate made of a metal material such as stainless steel.
A, 12B are formed, three curling allowances 13A, 13B, 13C and flange portions 14A, 14B (14A is not shown) are formed on the other longitudinal side, and one each on the other two sides. It is made by forming the curling margins 15A and 15B, and then bending the entire board so that the longitudinal sides become U-shaped.

The top plate 8 has curling allowances 16, 17, 1.
8 and 19 are formed on the outer peripheral edges thereof, respectively.

Note that curling margins 13A, 13B, and
A plurality of projecting portions 20 are formed on each of 13C and 16, and are configured to be overlapped with a projecting piece 21 formed by cutting and raising the rear plate 7, and then joined by a curling process. ing.

Although not particularly shown in FIG. 4, the periphery of the opening 10 of the front plate 5 and each curling margin 13A, 13B, 1 of the top plate 8 and body plate 9 that constitute the cylindrical body part
3C and 18 are also curled and joined by a known method. Similarly, the curling margin 17 of the top plate 8,
19 and the curling margins 15A, 15B of the body plate 9 by a curling process.

By the way, each joint between the front plate 5, top plate 8, body plate 9 and rear plate 7 as described above has a curling margin as shown in FIG. By arranging them on the outside, it is possible to join them almost simultaneously. However, the fifth
As shown in the cross-sectional view of the joint portion between the top plate 8, the front plate 5, and the rear plate 7, the mold 31 (indicated by imaginary lines) in contact with the upper part of the top plate 8 is connected to the front plate. 5 and the rear plate 7 are brought into contact with the top plate 8 from the directions of arrows P and Q,
The other mold must be brought into contact with the other mold from the directions of arrows P and Q to perform the joining and then removed.
7a is formed, it cannot be removed in the direction of arrow R in FIG. However, after each joint is made, each bent piece 5a, 7a of the front plate 5 and the rear plate 7 is
If a mold having an expandable structure that allows the length in the lateral direction in the drawing of FIG. 5 to be shorter than the distance between the tips of the molds 31, it is easy to remove the mold 31 after joining. However, when this type of special mold is used, there is a problem that the equipment becomes large and a driving source is required, resulting in high manufacturing costs.

Therefore, in the conventional inner box 4 which is joined by a curling process, the rear plate 7 is provided with a bent piece 7a as shown in FIGS. 2 to 4, and does not serve as the rear plate of the outer box. The rear opening of the body 6 was simply closed, and the rear plate without the bent piece 7a was simply joined. That is, in the conventional inner box 4 joined by curling, the rear plate 7 cannot be used as the rear plate of the outer box. There was a problem that the number of parts could not be reduced and the cost was high.

OBJECT OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, to provide an inexpensive inner box for a cooking appliance that can be efficiently produced and has a small number of parts.

Structure of the Invention The present invention includes a cylindrical body, a front plate having an opening and joined to the front end of the cylindrical body, and a rear plate joined to the rear end of the cylindrical body. This is something that hangs over the inner box of cooking equipment. The front plate is provided at the front end of the cylindrical body, and includes a main wall located in a plane with respect to a cross section orthogonal to the cylindrical body, and a front plate provided at the periphery of the main wall and located at the rear. The main wall portion is located between the rear bent piece and the opening and is depressed toward the rear from the main wall portion. The length of rearward protrusion of the rear bent piece from the main wall in the direction orthogonal to the main wall is the same as or longer than the length of rearward protrusion of the depressed portion from the main wall. It has been shortened. The recessed portion of the front plate and one end of the cylindrical body are connected to each other by curling.

The rear plate is provided at the rear end of the cylindrical body, and is provided on a main wall located in a plane parallel to a cross section orthogonal to the cylindrical body, and on a periphery of the main wall. a front bent piece that is bent so as to extend forward; and a depressed part that is located away from the front bent piece toward the center and that is sunken forward from the main wall. Contains. The forward protrusion length of the front bent piece from the main wall in the direction orthogonal to the main wall is equal to or less than the forward protrusion length of the depressed portion from the main wall. It has been made shorter. The recessed portion of the rear plate and the rear end of the cylindrical body are connected to each other by curling.

Effects of the Invention The effects of the present invention will be explained with reference to FIG. 11.

According to this invention, the length of the forward protrusion of the bent piece 57a from the main wall in the direction orthogonal to the main wall is equal to the length of the forward protrusion of the depressed portion 58 from the main wall. They are the same (may be shorter). Further, the length of the bent piece 5a protruding rearward from the main wall in the direction perpendicular to the main wall is as follows:
The length of the recessed portion protruding rearward from the main wall portion is the same (or may be shorter). Therefore, the mold 61 (1
It can be seen that the material (indicated by the dotted chain line) can be easily removed in the direction of arrow A after bonding. Therefore, since the cylindrical body, the front plate, and the rear plate can be joined by curling, the inner box can be produced more efficiently than conventional joining by spot welding, riveting, or screwing.

In addition, in order to realize the inner box shown in FIG. 2, referring to FIG. 11, on the periphery of the rear plate 57 of the inner box 8,
A bent piece 5 that is bent so as to extend forward.
Contains 7a. Similarly, the periphery of the front plate 5 of the inner box includes a bent piece 5a that is bent so as to extend rearward. Therefore, the front plate of the inner box can also serve as the front plate of the outer box, and the rear plate of the inner box can also serve as the rear plate of the outer box. Therefore, the front plate of the outer case and the rear plate of the outer case, which were conventionally indispensable members, are no longer necessary, and the number of parts is reduced. As a result, it is possible to obtain an inexpensive inner box for cooking equipment.

Hereinafter, the details of the present invention will be clarified by describing embodiments with reference to the drawings.

DESCRIPTION OF THE EMBODIMENTS FIG. 6 is an exploded perspective view showing the steps of assembling an embodiment of the present invention, and corresponds to FIG. 4. As is clear from FIG. 6, also in this embodiment, curling margins 16, 11A, 11B, and 11C are formed on the rear edges of the top plate 8 and the body plate 9, and each curling margin has a plurality of curling margins. An overhanging portion 20 is formed. On the other hand, the rear plate 57 is
A main wall portion provided at the rear end of the cylindrical body portion 6 and located in a plane parallel to a cross section orthogonal to the cylindrical body portion 6; A bent piece 57a that was once bent so as to extend, and a part located away from the bent piece 57a toward the center,
It includes a depressed portion 58 that is depressed toward the front from the main wall portion. The recessed portion 58 is provided with a cut-and-raised piece to be joined to the overhanging portion 20 provided at each curling margin of the top plate 8 and the body plate 9. FIG. 7 is a view of the rear plate 57 viewed from the rear to show the arrangement of the cut and raised pieces 59. As is clear from FIG. 7, the cut and raised pieces 59 are formed by cutting out the bottom of the recessed portion 58 at a plurality of locations on the bottom of the groove 58.

8 and 9 show the overhanging portion 2 of the top plate 8.
FIG. 3 is a partially cutaway sectional view showing a joining process of 0 and a cut-and-raised piece 59 of a rear plate 57. As is clear from FIG. 8, on the rear edge of the top plate 8, a plurality of protruding parts 20 are formed on the curling margin 16 as described above, and on the other hand, on the bottom of the recessed part 58 of the rear plate 57. A cut-and-raised piece 59 is formed in the direction of the cylindrical body. Now, bring them both close together,
By bringing molds into contact with the joint from both sides, a curling process can be performed as shown in FIG. 9. Each curling allowance 11A of the body plate 9,
The overhanging portions 20 formed at 11B and 11C can also be joined to the cut and raised pieces 59 formed at the bottom of the recessed portion 58 of the rear plate 57. The joined state is shown in FIG. 10 in a partially cutaway sectional view.

By the way, in this embodiment, as shown in a partially cutaway cross-sectional view in FIG. The length of the portion 58 protruding forward from the main wall portion is the same. Further, the length of the bent piece 5a rearwardly protruding from the main wall in the direction perpendicular to the main wall is the same as the length of the recessed portion rearwardly protruding from the main wall. Therefore, as is clear from FIG. 11, the joint portion is located closer to the cylindrical body 6 than the tip of the bent piece 57a formed around the rear plate 57.
Therefore, as shown in FIG. 11, the front plate 5 is also provided with the joint portion located closer to the cylindrical body than the bent piece 5a of the front plate 5, so that there is a gap between the front plate 5 and the rear plate 57. The arranged mold 61 (indicated by a dashed line) is
It can be seen that it can be easily removed in the direction of arrow A after bonding. Therefore, in this embodiment, even if a front plate and a rear plate 57 that also serve as the front plate and rear plate of the outer box are used, that is, a front plate 5 and a rear plate 57 having bent pieces 5a and 57a on the periphery are used. However, the front plate 5, top plate 8, body plate 9, and rear plate 7 can all be joined almost simultaneously by curling. Therefore, production can be made more efficiently than conventional joining methods such as spotting, riveting, and screwing. Further, a bent piece 57a is formed on the periphery of the rear plate 57 of the inner box so as to extend forward, and a bent piece 57a is formed on the periphery of the front plate 5 of the inner box so as to extend rearward. A bent piece 5a is formed. Therefore, the front plate 5 of the inner box can also serve as the front plate of the outer box, and the rear plate of the inner box can also serve as the rear plate of the outer box, as shown in FIG. The rear plate 101 of the outer case and the front plate (not shown) of the outer case, which were conventionally indispensable, are no longer necessary, and the number of parts is reduced. As a result, an inexpensive inner box for cooking appliances is obtained.

In the above description, the overhanging portion 20 formed on the rear edge of the top plate 8 and the cut-and-raised piece 59 of the rear plate 57 are joined to each other. Cut-and-raised piece 5 of the overhanging portion 20 and the rear plate 57
It goes without saying that 9 is also joined in the same way.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a microwave oven to which the present invention is applied. 2 is a perspective view schematically showing an example of the inner box of the microwave oven shown in FIG. 1. FIG. 3 is a partially cutaway perspective view showing the joint structure of the inner box shown in FIG. 2. FIG. Figure 4 shows
FIG. 4 is an exploded perspective view for explaining a process of joining the inner box shown in FIG. 3; Figure 5 is similar to Figures 3 and 4.
FIG. 3 is a partially cutaway sectional view for explaining problems when joining the inner boxes shown in the figure. FIG. 6 is an exploded perspective view for explaining the process of joining an embodiment of the present invention, and is a view corresponding to FIG. 4.
FIG. 7 is a view of the rear plate of the embodiment shown in FIG. 6, viewed from the rear. 8 and 9 are partially cutaway sectional views showing the process of joining the top plate and the rear plate in the embodiment shown in FIGS. 6 and 7. FIG. FIG. 10 is a partially cutaway sectional view showing the joint portion of the embodiment described with reference to FIGS. 6 to 9. FIG. FIG. 11 is a partially cutaway sectional view for explaining the abutment and removal process of the mold when obtaining the joining structure shown in FIG. 10. FIG. 12 is a sectional view of a conventional joint between an outer box and an inner box. In the figure, 1 is a microwave oven as an example of cooking equipment, 4 is an inner box, 5 is a front plate, 6 is a cylindrical body, and 8 is a microwave oven.
9 is a top plate forming a cylindrical body; 9 is a body plate forming a cylindrical body; 10 is an opening in the front plate; 20 is provided at the rear edge of the top plate and the body plate, and is connected to the rear plate An overhanging portion, 57 is a rear plate, and 59 is a cut and raised piece of the rear plate to be joined to the cylindrical body.

Claims (1)

[Scope of Claims] 1. A cylindrical body, a front plate having an opening and joined to a front end of the cylindrical body, and a rear plate joined to a rear end of the cylindrical body. In the inner box of the cooking appliance, the front plate is provided at the front end of the cylindrical body and includes a main wall portion located in a plane parallel to a cross section orthogonal to the cylindrical body; a rear bent piece provided on the periphery of the main wall and bent to extend rearward; and a rear bent piece provided on the periphery of the main wall and extending rearward from the main wall located between the rear bent piece and the opening. a depressed portion, and a length of the rearwardly bent piece protruding backward from the main wall in a direction perpendicular to the main wall is equal to The length of the rear plate is equal to or shorter than the length of the rearward protrusion, and the recessed portion of the front plate and one end of the cylindrical body are connected to each other by curling, and the rear plate is connected to the cylindrical body. A main wall portion provided at the rear end of the cylinder body and located in a plane parallel to a cross section perpendicular to the cylindrical body portion; a bent front bent piece; and a recessed part located away from the front bent piece toward the central portion and depressed forward from the main wall, with respect to the main wall. The length of the front bent piece protruding forward from the main wall in the orthogonal direction is equal to or shorter than the length of the depression forward from the main wall, and the rear plate An inner box for a cooking appliance, characterized in that the recessed part and the rear end of the cylindrical body are connected to each other by curling.