JPH11351578A - Microwave oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of a microwave over by disposing a decorative plate on a top surface of the microwave over to restrict top surface temperature, and integrally forming with an inexpensive plated steel plate a top surface section, a rear surface section, and a bottom surface section constituting a metal outer configuration and employing it as it is as a raw material. SOLUTION: In a microwave over where it includes an upper heater 5 for heating any food contained in a heating chamber 1 from an upper portion, an outer configuration is constructed with a top surface.rear surface.bottom surface member 10 obtained by integrally forming a top surface section 10a, a rear surface section 10b, a bottom surface section 10c and with left and right side surface plates, and further the top surface section 10a is covered with a decorative plate 12 to construct the outer configuration of a product body. The top surface.rear surface.bottom surface member 10 is integrally formed with an inexpensive plated steel plate as it is as a raw material. Further, since only left and right flat plate shaped side surface plates are employed as metal outer configuration parts, there is reduced in total the cost including storage of parts and management of transportation and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer structure of a microwave oven, and more particularly to a cabinet top plate, a rear plate,
The present invention relates to a structure in which a bottom plate is integrally formed.

[0002]

2. Description of the Related Art FIG. 6 is an external perspective view showing an open state of a general microwave oven. A door 2 is attached to a front opening of a heating chamber 1 so as to be openable and closable, and a right side of the front opening. Is provided with an operation panel 3. The outer shell of the microwave oven body is a cabinet 4 integrally formed with both side surfaces and the top surface.
And a rear plate and a bottom plate. FIG. 7 is an external perspective view of the cabinet 4, which is generally formed of a painted steel plate and bent into a U-shape by press working. This is because the cabinet 4 has the appearance of the product.

[0003] A U-curved portion 4 is provided at the front peripheral end of the cabinet 4.
are provided on the left and right ends and the upper end at appropriate intervals, and the U-curved portions 4a are provided on the front plate 1 of the heating chamber 1.
It is inserted and fixed to the rear folded piece provided at the peripheral end of the "a".
Screw fixing holes 4b and 4 are provided on the rear end flange of cabinet 4.
are provided, and screws are fixed to lower screw holes of a rear plate (not shown) provided corresponding to the holes 4b.

As the coated steel sheet used for the cabinet 4, a coated galvanized steel sheet (Pretec Mitsubishi Plastics), a polyvinyl chloride metal laminate (Hishimetal Mitsubishi Plastics), or the like is used. This painted steel plate is 1.5 to 2 times as expensive as the plated steel plate used for the rear plate and the bottom plate. Also, since the back surface is also coated, it is not easy to attach another component by welding. Further, since the cabinet 4 is an external component, it is not easy to screw another component.

Generally, a cooking book, a plastic container, a vinyl-based sheet, or the like is placed on the top surface of the cabinet 4. A vase with water may be placed inside as an interior. Since the top surface temperature of a microwave oven with a heater becomes 100 ° C. or higher, if the above-mentioned object is placed on the microwave oven, it is melted or deformed. If the plastic melts, it sticks to the top surface of the cabinet 4 and no trace is obtained. Therefore, a heat insulating material such as glass wool is provided between the reflector of the upper heater and the top surface of the cabinet 4 or a heat shield plate is provided to suppress a rise in the temperature of the top surface of the cabinet 4.

[0006] In some cases, the temperature inside the heating chamber or outside the heating chamber is detected and controlled to suppress a rise in the temperature of the top surface of the cabinet. Further, Japanese Patent Application Laid-Open No. 8-159482
As described in Japanese Patent Application Laid-Open No. HEI 7-83447, the temperature of the cabinet top surface is suppressed by forced cooling by a fan.

FIG. 8 is a side sectional view of a main part of the microwave oven shown in FIG. 6 with a door removed, and the heating chamber 1 is spot welded or caulked to the upper wall, the left, right, and inner side walls and the lower wall. They are connected by processing, and are formed by spot welding a front plate having a substantially square frame shape to the opening. An upper heater 5 and a reflection plate 6 are attached to an upper portion of the heating chamber 1, and a turntable unit 7 is attached to a lower portion. After the assembly and inspection of the inside of the main body are completed, the cabinet 4 is assembled in a final assembling step by fixing the front portion with U-curved portions 4a, 4a, and fixing the rear portion with screws.

[0008] JP-A-8-219467, JP-A-9-219
Japanese Patent Application Laid-Open No. 199,269 describes a method of assembling a plate obtained by pressing a bottom plate 8 and a rear plate 9 forming an outer shell into a flat plate shape by hand bending. This is a method in which a high-voltage transformer, a fan motor assembly, and the like are attached to a plate-shaped member in advance, and then hand bending is performed. Also in this case, the form and assembly of the cabinet 4 are the same as those described above.

The cabinet 4 is a paint-finished exterior part, and the bottom plate 8 and the rear plate 9 are located at the bottom and the rear of the product and are not easily seen by the user. It was difficult to think about integrating the top surface of the cabinet 4 and the rear plate 9 with the same material.

[0010]

The above prior art has the following problems. 1) The temperature rise of the cabinet is so high that no objects can be placed on the top of the cabinet. Objects can be damaged when placed.

2) A component such as a temperature detecting element cannot be directly attached to the cabinet. For this reason, there is a problem that accuracy cannot be improved and responsiveness is slow because the heating control cannot be performed by measuring the temperature of the top surface of the cabinet itself.

3) Since the top surface of the cabinet is flat, when water overflows on the top surface, the water travels along the rear plate, enters the exhaust port, and enters the inside of the set. Then, the water that has entered the interior causes insulation failure of the electric component, thereby causing a failure. Further, the steel plate inside may be rusted.

4) In order to prevent the heat of the upper heater from being transmitted to the cabinet top surface, a method of providing a heat insulating material or a heat shield plate inside the set cannot sufficiently suppress the rise in the top surface temperature and increase the cost of parts. In addition, in the forced air cooling, the temperature in the heating chamber also decreases, so that the time required to rise to the set temperature becomes longer, and the thermal efficiency decreases.

5) Although the bottom plate and the rear plate were integrated, the top plate could not be integrated for the above-mentioned reason.

6) Since the parts of the cabinet have a U-shape and are external parts, storage of the cabinet,
It required careful attention during transport and required a lot of storage space.

[0016]

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and an invention according to claim 1 is an electronic apparatus having an upper heater for heating food stored in a heating chamber from above. In the microwave oven, the outer shell made of metal is composed of top, rear, and bottom members integrally formed with a top surface, a rear surface, and a bottom surface, and left and right side plates. It constitutes the outer shell of the main body, and by this configuration,
The top, back, and bottom members can be integrally formed of inexpensive plated steel plate and used as a fabric, and the microwave oven top surface (mounting surface) can be used without providing heat insulation or heat shield plates inside the set. ) Can be kept low. In addition, since only the left and right side plates having a flat shape are used as metal external parts, total cost reduction including storage, transportation, and management of the parts can be achieved.

According to a second aspect of the present invention, the bent portions of the top, rear, and bottom members are subjected to easy bending which can be easily bent by hand.
Bending can be easily performed by hand in the overall assembly process of the microwave oven main body, and the storage and transportation of the top, rear, and bottom members can be performed in a flat plate, which is cost-effective. Since parts can be attached to the rear and bottom members in a flat state, work efficiency is improved, and automation of assembly is facilitated.

According to a third aspect of the present invention, the decorative board is made of a resin. With this configuration, the temperature of the decorative board can be kept low because the heat conduction of the resin is small.

According to a fourth aspect of the present invention, the decorative plate is provided with a downward slant. With this structure, even if water is overflowed on the decorative plate, it flows down to the front side. Accidents and problems caused by water intrusion into the interior can be eliminated.

According to a fifth aspect of the present invention, a metal reflecting plate is provided on the lower surface side of the decorative plate, at a position facing the upper heater provided inside the main body. With this configuration, it is possible to suppress a local rise in temperature located above the upper heater.

The invention according to claim 6 is characterized in that the side plate on the side where the electrical components are stored can be independently attached and detached. With this configuration, inspection and repair can be performed simply by removing one side plate. The time required for inspection and repair work can be reduced.

[0022]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional side view of a main part of a microwave oven according to the present invention with a door removed, and FIG. 2 is an enlarged top view of the microwave oven shown in FIG. The same or corresponding parts as in the prior art are denoted by the same reference numerals, and the description of those parts is omitted.

The most characteristic feature of the present invention is that the top surface, the rear surface, and the bottom surface constituting the metal outer shell are integrally formed of a low-cost (hot-dip galvanized) steel plate and used as a fabric. It has a structure that covers the surface with a decorative board. The heating chamber 1 has the same configuration as the conventional one, and a description thereof will be omitted.

Integrated part 1 of top, rear and bottom
0 (hereinafter referred to as the top, rear, and bottom members), as shown in FIG. 3, the top surface 10a, the rear surface 10b, and the bottom surface 10c are integrally punched, and the broken line is bent by press working, and manually processed. It is formed by performing bending of the easily bendable processing portions 10d, 10d, which are provided with long holes continuously so as to be easily bent, at the time of assembling a product.

Necessary parts such as a high-voltage transformer (not shown) and a fan motor (not shown) are mounted on the top, rear and bottom members 10 in a state where the broken line portion is bent by press working, and wiring work is performed. After that, place the heating chamber 1
e and the holes at the lower end of the front plate of the heating chamber 1 are aligned and fixed with screws 11.

Next, the top / rear / bottom member 10 to which the lower end of the heating chamber 1 is attached is attached to the easily bendable portion 10d.
The upper surface portion 10a, the rear surface portion 10b, and the bottom surface portion 10c are formed on the outer wall by bending in a U shape along 10d.

Next, the holes provided at the upper end of the front plate of the heating chamber 1 are aligned with the holes 10f provided at the front end of the top surface, the rear surface and the bottom surface member 10 and fixed with screws 11. The outer shells other than the both sides are now assembled.

Since the top, rear, and bottom members 10 in the form of flat plates that have been bent by press working in the broken line portion are transported or stored, the space required for parts management is small,
An efficient production system becomes possible. In addition, since it is not an external part, attention in handling is reduced. Furthermore, the mechanical strength in the state combined with the heating chamber 1 is strong, and it is easy to carry during the production process.

In a conventional microwave oven, the strength is low in a semi-finished product state in which the cabinet 4 is not attached.
There were many problems when carrying semi-finished products off the conveyor line and carrying them.

A resin-molded decorative plate 12 is attached above the top surface 10a. Attachment is performed by hooking a nail 12a provided at a rear portion of the decorative plate 12 into an elongated hole provided in the easily bendable processing portion 10d of the top surface, the rear surface, and the bottom surface member 10, and fixing a front portion of the decorative plate 12 with a countersunk screw 13. This is achieved by fixing to the surface portion 10a. On the front side of the decorative plate 12, a screen-shaped barrier 12b is provided so that the head of the screw 11 cannot be seen.

A temperature detecting element 14 is attached to the top surface 10a with a screw 15. Since the temperature detection element 14 is directly attached to the top surface 10a, the surface temperature of the top surface 10a can be accurately and quickly detected. The upper limit temperature controlled by the temperature detecting element 14 is set so that the surface temperature of the decorative board 12 is 70 ° C. or less. Further, the mounting position of the temperature detecting element 14 is provided at a position slightly away from the position of the reflecting plate 6. This is because, in the vicinity of the reflection plate 6, the temperature of the upper heater 5 is so great that accurate temperature detection is difficult. The temperature detecting element 14 may be a thermistor, a thermocut, a thermostat, or the like.

If a heat shield plate 16 made of a metal plate is attached to the decorative plate 12 in advance above the reflecting plate 6, local rise in temperature of the decorative plate 12 can be reduced. The heat shield plate 16 may be a steel plate, but is preferably an aluminum plate having good heat reflection efficiency.

FIG. 4 shows a decorative plate 12 in which the front side is low and the rear side is high, and the front side is inclined downward.
The inclination angle of the forward fall is an angle at which an object is placed on the inclined surface. The reason for providing the downward slope is to make the water flow down from the front side when the water is zeroed on the inclined surface. The inner surface of the decorative plate 12 is also inclined similarly to the front surface. The inclination on the inner surface side is for smoothly discharging the hot air inside the decorative plate 12. Decorative board 1
Since the heated air inside 2 moves upward while moving backward, it is necessary to ensure that the air is discharged smoothly.

As shown in FIG. 5 (only the right side plate 17 is shown), the left and right side plates constituting the outer shell have U-curved portions 17a, 17a The rear end side is screwed and fixed to the rear surface portion 10b of the top / rear / bottom member 10 via screw holes 17b / 17b. Since the left and right side plates are external parts, painted steel plates are used as before. Since the size is smaller than the conventional cabinet 4 and the shape is flat, parts management such as transportation and storage becomes easy. Further, since the shape is small, the amount of the coated steel sheet used is small, which is advantageous in terms of cost.

Further, since electrical components are provided in a concentrated manner on the right side, when checking the inside of the set for inspection or repair, inspection and repair can be performed only by removing the right side plate 17. There is an advantage. Conventionally, it is necessary to remove a lot of screws to remove the cabinet 4. When the cabinet 4 is removed, the top and left sides that are unnecessary for inspection and repair are opened, and high voltage application parts such as magnetrons and high-voltage transformers are opened. There is a risk of touching, and the present invention is superior in safety.

By mounting the resin decorative plate 12 above the metal outer top, it is not necessary to use a painted steel plate on the metal outer top, and it is possible to use a low-cost (fused zinc) plated steel plate. The bottom plate, the rear plate, and the top plate can be integrally formed. By integrally forming, the heat of the top plate is conducted to the rear plate having a large surface area to suppress a rise in temperature. In addition, by providing the decorative plate 12 made of resin, the rise in temperature of the mounting surface can be suppressed to a low level. Inconveniences such as deformation and melting are eliminated even if objects are placed.

[0037]

According to the first aspect of the present invention, the top surface, the rear surface,
The bottom member can be formed as a single piece of inexpensive plated steel plate and used as it is. The microwave oven top surface (mounting surface) without the need for heat insulation or heat shield plates inside the set
Temperature can be kept low. In addition, since only the left and right side plates having a flat shape are used as metal external parts, total cost reduction including parts management such as storage and transportation of parts can be achieved.

According to the second aspect of the present invention, the bending process can be performed by hand in the overall assembling process of the microwave oven main body, and the top, rear and bottom members can be stored and transported in the form of a flat plate. Since the components can be attached to the top, rear, and bottom members in a flat state, work efficiency is improved, and automation of assembly is facilitated.

According to the third aspect of the present invention, since the heat conduction of the resin is small, the temperature of the decorative board can be kept low.

According to the fourth aspect of the present invention, with this configuration, even when water overflows on the decorative board, the water flows down to the front side, so that accidents and problems caused by the intrusion of water into the interior of the main body can be eliminated. .

According to the fifth aspect of the invention, a local rise in temperature located above the upper heater can be suppressed.

According to the sixth aspect of the present invention, inspection and repair can be performed only by removing the side plate on the side where the electrical components are stored, and the time required for the inspection and repair work can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part of a microwave oven according to the present invention with a door removed.

FIG. 2 is an enlarged top view of the microwave oven shown in FIG.

FIG. 3 is a view showing a punching state of a top surface, a rear surface, and a bottom surface member according to the present invention.

FIG. 4 is a sectional view of a main part showing a modification of the decorative board of the microwave oven according to the present invention.

FIG. 5 is a diagram showing a state of bending a top surface, a rear surface, and a bottom surface member according to the present invention. .

FIG. 6 is an external perspective view showing a door open state of the microwave oven.

FIG. 7 is an external perspective view of a cabinet in a conventional microwave oven.

FIG. 8 is a sectional side view of a main part showing a state where a door of a conventional microwave oven is removed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating room 4 Cabinet 5 Upper heater 6 Reflector 10 Top / back / bottom member 10a Top 10b Rear 10c Bottom 10d Bendable processing part 12 Decorative plate 16 Heat shield plate 17 Side plate

Claims (6)

[Claims] 1. A microwave oven provided with an upper heater for heating food stored in a heating chamber from above, wherein a metal shell is integrally formed with a top surface, a rear surface, and a bottom surface. -A microwave oven comprising a rear / bottom member and left and right side plates, wherein the top surface is covered with a decorative plate to form an outer shell of a product main body. 2. The microwave oven according to claim 1, wherein the bent portions of the top, rear, and bottom members are easily bent by hand. 3. The microwave oven according to claim 1, wherein said decorative board is made of resin. 4. The microwave oven according to claim 1, wherein said decorative plate is provided with a downward slope. 5. The microwave oven according to claim 1, wherein a metal reflector is provided on a lower surface side of the decorative plate and opposed to an upper heater provided inside the main body. 6. The microwave oven according to claim 1, wherein, of the side plates, a side plate on the side where the electrical component is stored is detachable alone.