JPH05149551A - Door panel connecting method - Google Patents

Abstract

PURPOSE:To simplify a process and reduce cost by a method wherein a punching plate for a door screen is fixed to a door panel member through seam caulking employing projections, produced upon dowel jointing between an inside door panel member and an outside door panel member, as retaining members for preventing deviation. CONSTITUTION:A door for a box type electric appliance is formed by working a metallic sheet. In this case, an inside door panel member 6 and an outside door panel member 7, which are constituting a door, are connected through dowel caulking while a punching plate 8 for a door screen is fixed to the door panels 6, 7 through seam caulking employing projections 11, produced by the dowel jointing, as retaining members for preventing deviation. According to this method, a printed steel sheet, a painted steel sheet and the like, which were difficult to joint through welding so far, become usable whereby the simplification of a manufacturing process and the reduction of manufacturing cost can be contrived.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door panel joining method, and more particularly to an improvement of a door panel joining method for electric appliances such as home electric appliances.

[0002]

2. Description of the Related Art At present, there are many electric appliances in the market, and their types and applications are diverse. Of these, thin metal plates, especially thin steel plates, are often used for equipment that involves opening and closing doors, because they are expected to have rigidity in addition to their durability, moderate weight, etc. It is assembled and joined by welding means such as spot welding, and finishes painting such as baking. FIG. 4 is a perspective view showing an example of a household microwave oven, which is one of the typical devices of such a product, in which a main body compartment 2 having a door 1 that can be opened and closed is heated in the compartment. A turntable 3 for cooking and a cooking selection panel 4 and an open door button 5 are provided outside.

In this case, the door 1 has a main metal part assembled from an inner door panel 6, an outer door panel 7, a punching plate 8 for a door screen, etc. In addition, if necessary, the door screen part may be formed on both sides with, for example, a transparent plastic plate. It is configured to be held between the two.
FIG. 5 is a partially enlarged cross-sectional view showing an example of a conventional assembling and joining means of the door having the above-mentioned structure, and it shows a punching plate 8 having an innumerable small holes 9 for visually recognizing the inside of the compartment, the inner door panel 6 and the outer door panel 7. The welding part 10 is provided by welding means to join the parts.

[0004]

However, in the case of such a welded structure, at least one of the door panel materials is a material such as a printed steel plate or a painted steel plate whose surface is previously coated or coated. When trying to perform spot welding, current cannot be energized by normal means,
Further, there is also a means for performing spot welding by destroying the coating with a large amount of electric power, etc. However, this will damage the coating of the corners and the like, so that the area around it must be repaired after welding. Therefore,
Usually, an uncoated unpainted metal plate, for example, a cold-rolled thin steel plate is cut into a desired panel size, welded, and then post-finished such as painting.

However, such means is not desirable in terms of manufacturing cost or process control. That is, in the first place, in the case of applying the post-finishing as described above, the cost thereof accounts for 30% or more of the unit price of the door panel. Furthermore, in the normal process, the areas of business activities of the parts processor and the paint finisher are not necessarily close to each other, so that a high cost associated with transportation between the two often occurs. Moreover, during such transportation, defects such as scratches and dents are likely to occur. In addition, there are many spatters and the like that are generated when welding is performed, and the spatters and the like remain in and adhere to the inside of the refrigerator, which may cause problems such as microwave discharge and local heating in the case of a microwave oven. Therefore, the object of the present invention is to use a thin metal plate, such as a printed steel plate or a coated steel plate, which has been difficult or almost impossible to weld in the past, and to simplify the manufacturing process and reduce the manufacturing cost. It is to provide a method of joining door panels.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and its gist is to process a metal plate and form it into a door portion of a box-shaped electric product. , While joining the inner door panel material and the outer door panel material that make up the door by blunting,
There is a door panel joining method in which a punching plate for a door screen is fixed to the door panel material by crimping as a locking member for preventing the protrusion generated thereby from slipping,
In particular, a printed or painted steel plate is used for at least one of the door panel materials.

[0007]

[Function] The inner door panel material and the outer door panel material are joined by the blunting means, and the side rising part of the protrusion generated at that time is used to prevent the shift for fixing the panel plate for the door screen. By performing the crimping and crimping with the press as the locking member, it is possible to stably join the door members without using a welding process. In this case, as a locking means for the punching plate, a hole having a size slightly larger than the outer diameter of the protrusion side surface rising portion is preliminarily formed at one end of the plate, and the panel is pressed into the hole while pressing the hole. The product should be folded and crimped together with the material, or a clearance should be provided between the protrusion and the end of the panel material, and one end of the punching plate should be bent and fitted into that part in advance and then folded together with the panel material by pressing. Since the caulking is performed, the panel material and the punching material are fixed with strength and dimensional accuracy comparable to the welding means.

[0008]

1 is a partially enlarged cross-sectional view of a door panel showing an example of an intermediate step of the joining method of the present invention, in which an inner door panel 6 and an outer door panel 7 are joined by blunting and a projection 11 is formed. This is a state in which is generated.
Reference numeral 12 is a seam portion used in the subsequent seam folding process.
In this case, in FIG. 1, the protrusion 11 is shown inside the door, and the joint 12 is shown with one end of the outside door panel member 7 protruding inside the door. However, the present invention is not limited to this. An appropriate mode can be selected according to the door design and the like. For convenience of the above description, the next step will be described with reference to FIG.

FIG. 2 is a partially enlarged sectional view of the door panel by the process of joining the punching plate 8 to the door panel materials 6 and 7 processed up to the stage of FIG. 1, in which numerous small holes 9 are provided. At the end of the punching plate 8, the protrusion 11
Has a hole 13 corresponding to the outer diameter of the rising portion of the side surface of the side wall. The both ends are bent so as to be aligned with the seam portion 12, and then processed by a press PP, and then folded and crimped. Is to do. By processing in this way, the protrusions 11 are joined in a state of being fitted in the holes 13, so that unlike the case where the seams are simply folded and crimped,
It is possible to obtain an excellent joint portion in which no displacement occurs between the joining members.

FIG. 3 is a partially enlarged sectional view of a door panel according to another embodiment of the process of the present invention,
Instead of providing the holes 13 as shown in FIG. 2 at the ends of the punching plate 8, the spacing between the projections 11 and the claws 12 at one end of the inner and outer door panel members 6, 7 is made slightly longer, so that A clearance t is provided between the bent end and the protrusion 11, and the work is pressed by the press PP to perform the crimping. By processing in this manner, the end portions of the punching plate 8 are restrained by the side surface rising portions of the protrusions 11, and unlike the case where only the crimping and crimping is performed, excellent joining in which no deviation occurs between the joining members is achieved. Part is obtained.

The door panel joining method of the present invention is based on the above-mentioned means and does not involve a welding process. Therefore, a metal plate such as a color steel plate, which has been painted or printed in advance at the time of shipment, is printed. It is possible to select the desired design and color tone such as printed steel plate, painted steel plate, etc. from the beginning to assemble, and it is also possible to use materials such as aluminum, which has been difficult to weld in the past. Becomes Also used door panel material,
The materials such as punching material need not all be the same material, for example one of the inner door panel material and the outer door panel material can be printed or painted steel sheet and the other can be another material. This is possible because no welding structure is used. Of course, if all printing or coating materials are selected as the door panel material, the door panel can be a finished product without requiring painting finish. The plate thickness is not particularly limited and can be arbitrarily selected.

Although the punching plate is used for the door panel which is the object of the present invention as described above, the punching plate can be formed by using both the dulling and the folding clinching as shown in FIG. 2 or 3. It is possible to use a thin plate. That is, if only the means for crimping at points, such as blurring, is adopted, if the plate thickness becomes thin, the edge of the plate may rise unless the caulking interval is extremely narrowed. Moreover, the bonding strength at each point is only small. However, by additionally using the surface crimping and the crimping crimping, it is possible to prevent the end portion from being lifted up, and the bonding strength is significantly improved. In addition, since the punching plate can be made thin, the size of the small holes (for example, the small holes 9 in FIG. 2) for visually recognizing the inside of the microwave oven can be reduced, and the number of holes in the same area can be reduced. Therefore, it is possible to increase the opening ratio and improve the visibility of the inside of the refrigerator.

The inner end surface of the small hole may be lit by a lamp or the like, which may cause a problem in appearance. In such a case, only the punching plate should be coated after perforating and then the caulking step described above. You can use it. In this case, a part of the coating process will be added, but the surface area of the punching plate occupies about 1/3 of the entire door panel, so the cost will be reduced compared to the conventional process, and of course the welding process. Therefore, as far as the method of the present invention as a whole is concerned, the expected advantages are much larger, such as the omission of steps, the expansion of the degree of freedom in material selection, and the elimination of concerns such as discharge due to the occurrence of spatter. Is.

[0014]

According to the present invention, since the method of joining door panel parts is based on the application of mechanical caulking means, welding equipment and welding technology are not required. It is possible to avoid restrictions on the surface condition, inconveniences associated with the generation of spatter due to welding, etc., and because painting after joining is not necessary,
Significant omission of processes and cost reduction are expected. Furthermore, as the number of processes is reduced, the need for miscarriage between various processing companies and coating companies is reduced, so defects such as flaws and dents associated with transportation can be significantly reduced, and the yield can be significantly reduced. It is extremely large, though it also contributes to improvement.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a door panel showing an example of an intermediate stage of a joining method of the present invention.

FIG. 2 is a partially enlarged sectional view of a door panel showing an embodiment of the joining method of the present invention.

FIG. 3 is a partially enlarged cross-sectional view of a door panel showing another embodiment of the joining method of the present invention.

FIG. 4 is a perspective view showing an example of a household microwave oven.

FIG. 5 is a partially enlarged sectional view of a door panel showing an example of a conventional joining method.

[Explanation of Codes] 1 Door 2 Main Cabinet 6 Inner Door Panel 7 Outer Door Panel 8 Punching Plate 9 Small Hole 10 Welding 11 Protrusion 12 Groove 13 Hole

Claims (2)

[Claims] 1. When processing a metal plate to form a door portion of a box-shaped electric product, the inner door panel material and the outer door panel material that form the door are joined by blunting, and this is caused A door panel joining method, characterized in that a punching plate for a door screen is fixed to the door panel material as a locking material for preventing the projections from being displaced by crimping. 2. The door panel joining method according to claim 1, wherein at least one of the inner and outer door panel materials is a printed or painted steel plate.