JP2877596B2 - Punched metal for microwave oven and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a punching metal and a manufacturing method thereof for a microwave oven relates used for electric wave shielding doors electronic range.

[0002]

2. Description of the Related Art For example, a door of a microwave oven is provided with a see-through window so that a user can look inside a cooking chamber from the outside. The see-through window is formed by covering a radio-shielding punching metal formed by punching a large number of small holes in a thin iron plate with a glass plate.

[0003] The punching metal is provided on the outer frame of the door having a relatively large thickness. If the punching metal is formed integrally with the outer frame with a uniform thickness, the punching metal has a large thickness. There is a situation that the visibility of the window from an oblique direction is deteriorated. In addition, if the entire punching metal including the outer frame is made of a thin integral body, the rigidity of the entire body is reduced, warpage is likely to occur, and the mounting strength is also reduced.

[0004]

Therefore, conventionally, as shown in FIGS. 5 and 6, a relatively thin punching metal 3 having a large outer frame 1 and a plurality of small holes 2 formed in a plate surface.
Is mounted by welding so as to cover the opening 1a of the outer frame 1.

However, such a configuration has the following disadvantages. That is, first, although the punching metal 3 is relatively thin (thickness is, for example, 0.5 mm), it cannot be made sufficiently thin to secure the mounting strength of the welded portion, and the visibility is improved. Did not perform well.

Further, since the outer frame 1 and the punching metal 3 are formed as separate members, waste of material is increased, such as punching of the opening 1a of the outer frame 1, and a separate welding step is required. I was

In addition, it is necessary to reduce the welding pitch in order to prevent radio waves from leaking from the joint, and to ensure sufficient welding strength.

[0008] The present invention has been made in view of the above circumstances, when one object that is used to transparent window portion of the door of the electronic oven, with can improve the visibility, a sufficient attachment strength It is to provide a punching metal for a microwave oven that can be secured.

Further, when another object of the present invention is used in the transparent window portion of the door of the electronic oven, with can improve the visibility, the punching metal that can ensure a sufficient attachment strength An object of the present invention is to provide a method for producing punched metal for a microwave oven suitable for production.

[0010]

According to the present invention, there is provided a punching metal for a microwave oven , wherein a thinner frame portion having a large number of small holes is formed around a thinner frame portion. those having features to a location that has in one product.

Further, the method for manufacturing a punching metal for a microwave oven according to the present invention has a thin frame portion formed with a large number of small holes, and a single frame portion thicker than the thin portion. A first punching step of punching and forming an escape hole at a position corresponding to the small hole of a plate material having a thickness corresponding to the frame portion, and a method of manufacturing the punched metal for a microwave oven comprising the steps of: Pressurizing a portion corresponding to the portion to spread the plate material inward of the relief hole to form the thin portion, and punching and forming the small hole in the extended thin portion. It is characterized in that the second drilling step is performed in order.

[0012]

According to the punching metal for a microwave oven of the present invention, around a thin-walled thin portion having a large number of small holes,
Since the thick frame portion is provided as a single component, there is no need to separately join the frame portion and the thin portion, and material waste can be reduced as compared with a separate component. Since the frame portion and the thin portion are integral, even if the thin portion is made sufficiently thin, sufficient mounting strength can be ensured by the thick frame portion, and the occurrence of warp deformation as a whole is suppressed. it can, in the case of using the radio wave shielding doors electronic range, it is possible to improve the visibility of the transparent window portion.

Conventionally, it has been considered difficult to integrally form a thin thin portion in a thick frame portion. However, according to the method for manufacturing a punched metal of the present invention, by forming an escape hole in the plate material in the first punching step, a thin portion is formed inside the thick frame portion by the next pressing step. Can be integrally formed by spreading.
And the material escapes into the escape hole in the pressurization process,
In the second drilling step, small holes are punched and formed to produce a punched metal.

Therefore, it is possible to manufacture a punching metal having a thin portion that is sufficiently thin and that can secure the overall strength by the frame portion without the need for joining and with less waste of material. Also, the piercing and pressurization can be made relatively simple, and an integrated product can be easily manufactured.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to shielding a radio wave at a see-through window of a microwave oven door will be described below with reference to FIGS. First, the configuration of the door 11 of the microwave oven will be briefly described with reference to FIG.

That is, reference numeral 12 is a door body having a rectangular shape.
This is composed of an outer plate 13 made of punched metal according to the present embodiment, which will be described in detail later, and an inner plate 14 made of, for example, an iron plate in a rectangular frame shape. Of these, inner plate 14
Is attached, for example, by welding to the back side of a peripheral portion (a frame portion described later) of the outer plate 13.

A sash 15 is attached to an outer peripheral portion of the door body 12, and a transparent outer barrier 16 made of, for example, a glass plate is attached to the sash 15 so as to cover the front surface of the outer plate 13. ing. Further, on the back side of the door main body 12, a transparent inner barrier 17 also made of a glass plate is provided so as to cover the inside of the opening of the inner plate 14.
Are attached by a seal member 18.

Although not shown in detail, the door 11 configured as described above is pivotally supported by the front part of the inner box 20 constituting the cooking chamber 19, so that the front opening of the cooking chamber 19 can be opened and closed. It is designed to be closed.

The door 11 is provided with a see-through window 21 so that a user can look inside the cooking chamber 19 from outside.
Is provided. The see-through window 21 is formed by forming a number of small holes in the outer plate 13 sandwiched between the transparent outer barrier 16 and the inner barrier 17 on both sides at a rectangular portion at the center of the outer plate 13. It is supposed to be.
Hereinafter, the outer plate 13 will be described in detail with reference to FIGS. 1 and 2.

The outer plate 13 is made of, for example, an iron plate, and is formed integrally with a rectangular frame portion 22 and a thin portion 23 in the frame portion 22, and has a substantially rectangular plate shape as a whole. As shown in FIG. 2, the frame portion 22 has a relatively large thickness a, for example, 0.6 to 0.8 mm, and the thin portion 23 has a thickness b, for example. 0.2-0.3
mm and thin.

In the thin portion 23, a number of small holes 24 are punched and formed in an aligned state over the whole. In this case, the diameter of the small hole 24 is, for example, 1.2 mm, and the pitch is, for example, 1.6 mm. The small holes 24 allow the inside of the cooking chamber 19 to be visually recognized from the see-through window 21 in a state where the radio wave shielding function of the outer plate 13 is secured.

Next, a procedure for manufacturing the outer plate 13 configured as described above will be described with reference to FIG. The manufacturing of the outer plate 13 is performed using a press device (not shown). The press device performs the following three processing steps while sequentially feeding the plate material 25 made of an iron plate. Has become. Here, the plate member 25 has a thickness (dimension a) corresponding to the frame portion 22 in advance.
And is formed in a shape corresponding to the outer shape of the outer plate 13.

In manufacturing the outer plate 13, first,
A first drilling step is performed. In this first drilling step, as shown in FIG.
6 are formed by punching, and this escape hole 26
For example, it is formed at a position corresponding to the small hole 24 of the outer plate 13 having the final shape with a diameter (1.2 mm) and a pitch (1.6 mm) equivalent to the small hole 24.

When the first drilling step is completed,
A pressing step is performed. In this pressing step, the plate 2
5 is performed by pressing a central rectangular portion corresponding to the thin portion 23 of the outer plate 13 having the final shape from above in FIGS. 1 and 3. By this pressing step, FIG.
As shown in (b), the central rectangular portion of the plate 25 is extended so that the portion of the plate 25 that corresponds to the thin portion 23 escapes toward the inside of the escape hole 26. Accordingly, the thin portion 23 having a thin plate shape (thickness dimension b) is formed integrally with the surrounding thick frame portion 22 on the plate material 25.

Then, through this pressurizing step,
Since the escape hole 26 formed in the first drilling step cannot keep its original shape, finally, the second drilling step is executed. In the second drilling step, as shown in FIG. 3C, the thin portion 23 formed in the pressing step is punched again so that the small hole 24 has the above-described diameter and pitch. It is formed.

Through the above steps, the outer plate 13 having a single frame portion 22 thicker than the thin portion 23 is formed around the thin plate portion 23 in which a number of small holes 24 are formed. Things.

As described above, according to the outer plate 13 of the present embodiment, since the thin frame portion 23 has the thick frame portion 22 in one body, the outer frame shown in FIGS. Unlike the conventional one in which the perforated metal 3 is welded to 1, the frame portion 22 and the thin portion 23 do not need to be separately joined, radio wave leakage from the joined portion can be eliminated, and material waste can be reduced. . In addition, since the thin frame 23 is formed as a single piece with the thick frame 22, even if the thin wall 23 is made sufficiently thin, the overall rigidity can be ensured and the occurrence of warpage can be suppressed. Thereby, sufficient mounting strength can be ensured.

Therefore, the conventional one (for example, 0.5 m thick)
m), the thickness dimension b of the thin portion 23 can be significantly reduced (0.2 to 0.3 mm). As a result, the inside of the cooking chamber 19 can be sufficiently viewed even from an oblique direction, The visibility of the see-through window 21 was greatly improved.

According to the method of manufacturing the outer plate 13 of this embodiment, the outer plate 13 which can improve the visibility as described above and can secure sufficient mounting strength can be used without the need for joining. In addition, the production can be performed with less waste of material. Then, by forming the escape hole 26 in the plate member 25 in the first punching step, by the next pressing step,
The thin thin portion 23 can be integrally formed inside the thick frame portion 22 by spreading, and in this case, the frame portion 22 can be easily connected to the frame portion 22 only by performing relatively simple steps of punching and pressing. The thin portion 23 can be integrally formed.

[0030]

As is apparent from the above description, according to the punching metal for a microwave oven of the present invention, the thickness of the thin-walled portion having a large number of small holes is increased around the thin-walled portion. since a such frame part in one product, when used in the transparent window portion of the door of the electronic oven, with can improve the visibility was excellent in that it is possible to ensure a sufficient mounting strength effects To play.

Further, according to the method for manufacturing a punching metal for a microwave oven of the present invention, a first punching step of punching and forming an escape hole at a position corresponding to a small hole of a plate having a thickness corresponding to a frame portion, Pressurizing a portion corresponding to the thin portion of the sheet material to spread the plate toward the inside of the relief hole to form a thin portion, and punching and forming the small hole in the extended thin portion. a second perforation step since be executed in the order of, upon being used in the transparent window portion of the door of the electronic oven, with can improve the visibility, punching can be ensured sufficient attachment strength The present invention has an excellent effect that metal can be easily manufactured without the need for joining and with less waste of material.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a main part of a punched metal showing one embodiment of the present invention.

FIG. 2 is a partial rear view of a punching metal.

FIG. 3 is a longitudinal sectional view for explaining a manufacturing procedure of the punching metal.

FIG. 4 is a partial cross-sectional plan view of a microwave oven door.

FIG. 5 is a diagram corresponding to FIG. 1 showing a conventional example.

FIG. 6 is a diagram corresponding to FIG. 2;

[Explanation of symbols]

In the drawing, 11 is a door, 12 is a door body, 13 is an outer plate (punched metal), 16 is an outer barrier, 17 is an inner barrier, 19
Denotes a cooking room, 21 denotes a transparent window portion, 22 denotes a frame portion, 23 denotes a thin portion, 24 denotes a small hole, 25 denotes a plate material, and 26 denotes an escape hole.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B21D 28/26 H05B 6/76

Claims (2)

(57) [Claims] 1. A around a large number of small holes are formed thin plate-shaped thin portion, microwave punching metal comprising a thick walled frame portion than the thin portion in one product. 2. A method of manufacturing a punching metal for a microwave oven , comprising a thin plate-shaped thin portion having a large number of small holes formed around a frame portion thicker than the thin portion. A first punching step of punching and forming an escape hole at a position corresponding to the small hole of a plate material having a thickness corresponding to the frame portion;
A pressurizing step of pressing a portion corresponding to the thin portion of the plate to spread the plate toward the inside of the escape hole to form the thin portion; and method for producing a microwave punching metal and executes a second hole forming step of forming punching a small hole in order.