JPH0765749B2 - Open range - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a heater unit, a heat insulating material,
The present invention relates to a microwave oven provided with a heat shield plate.

(Prior Art) Conventionally, a microwave oven has a structure in which a sheath heater is provided in each of an upper portion and a lower portion in a heating chamber, and heat generation of the sheath heater is used to perform oven cooking or grill cooking. .

However, such a structure has a difficulty in cleaning the upper and lower surfaces of the heating chamber because the heater is installed so as to block the upper and lower surfaces of the heating chamber.

Therefore, in recent years, a microwave oven without a heater has appeared in the heating chamber. In such a structure, a plate-shaped heater unit (consisting of insulating mica and a heater) is provided on the upper surface of the top plate of the heating chamber, and a heat insulating material and a heat shield plate are sequentially provided above the heater unit. . Specifically, as shown in FIG. 4, a plate-shaped heater unit a is arranged on the outer surface of the top plate c of the heating chamber b, and this is fixed by pressing it with a holding plate d from above, Heat is supplied to the heating chamber b through the plate c. In addition to the plate-shaped heat insulating material e provided on the upper surface of the holding plate d, the heat insulating material e and the substantially box-shaped heat shield plate f are provided on the outer surface of the top plate c so as to cover the periphery of the heater unit a. Was trying not to escape.

However, since such a microwave oven has a large heat transfer area of the heat shield plate f, a large amount of heat is transmitted from the top plate c.

(Problems to be solved by the invention) Therefore, the upper wall of the cabinet g is strongly heated by the radiant heat from the shielding plate f. Moreover, in addition to the radiation from the heat shield plate f, the heat convection between the cabinet g and the heating chamber a simultaneously heats the upper wall of the cabinet g,
The upper wall of cabinet g has a considerable temperature (above 130 ℃)
There is a problem of rising up to. In particular, the temperature of the upper wall portion of the cabinet g facing the space between the heating chamber a and the peripheral wall of the cabinet g (the space on the opposite side of the machine chamber), which is the side on which the heat of convection rises, is remarkable. there were.

The present invention has been made in view of such problems, and an object thereof is to provide an oven range capable of keeping the temperature of the upper wall of the cabinet low.

[Structure of the Invention] (Means and Actions for Solving Problems) The present invention relates to a heating chamber provided in a cabinet, a heater unit provided on an upper surface of a top plate of the heating chamber,
A heat insulating material provided on the upper side of the heater unit, a heat shield plate which covers the heat insulating material from the upper side and projects into a space formed between the cabinet and the heating chamber, and a heat shield plate provided at an end portion of the heat shield plate. And a projecting wall projecting downward, wherein the heat shield plate is provided with fixing legs for fixing the heat shield plate to the heating chamber outside the heater unit and the heat insulating material. ing.

Therefore, the amount of heat transferred to the upper wall of the cabinet is reduced because the heat convection in the space between the cabinet and the heating chamber hits the heat shield plate, and the heat convection in the space is blocked by the protruding wall. It Moreover, since the fixing legs of the heat shield plate are provided outside the heater unit and the heat insulating material, the heat reaching the heat shield plate from the heater unit, the heat insulating material and the top plate of the heating chamber to the heat shielding plate is extremely reduced. Therefore, the amount of heat transferred from the heat shield plate to the upper wall side of the cabinet is also significantly reduced, and as a result, the temperature of the upper wall of the cabinet is effectively suppressed.

(Embodiment) Hereinafter, the present invention will be described based on an embodiment shown in FIGS. 1 to 3. FIG. 3 shows a front cross section of a horizontal microwave oven to which the present invention is applied, and 1 is a cabinet,
Reference numeral 2 denotes a heating chamber arranged in the cabinet 1 on the left side. The waveguide 3 is provided with the magnetron 4 on the right side wall of the heating chamber 2, and the heater unit 5 is provided with the heat insulating material 6 and the heat shield plate 7 on the outer surface of the top plate 2a of the heating chamber 2. It is possible to perform range cooking, oven cooking, and grill cooking within 2.

The structure around the shielding plate 7 is shown in FIG. Next, its structure will be explained. In the heater unit 5, as in the above-mentioned "Prior Art", the heater 10 is installed inside the two insulating mica 8 and 9 to form a plate shape. Is used. Then, by using a holding plate 11 having substantially the same shape as the heater unit 5, all the heater unit plates are fixed in close contact with the outer surface of the top plate 2a. A plate-shaped heat insulating material 6 is arranged on the upper surface of the pressing plate 11, and a heat shield plate 7 is arranged on the upper side of the heat insulating material 6. As shown in FIG. 2, the heat shield plate 7 is provided with a plate surface portion 12 having an outer shape that covers the entire space above the heating chamber 2 except a part corresponding to the machine chamber 1a. Then, as shown in FIG. 2, the left and right end portions of the plate surface portion 12 are vertically bent downward to form projecting walls 13 at the left and right end portions of the plate surface portion 12, respectively. Furthermore, the plate surface portion 12
A fixed leg in which a part of the plate surface portion 12 is cut and raised downward on four corner sides corresponding to the upper and lower joint flanges 2b and 2b and the left and right end surfaces of the heat insulating material 6, respectively.
A structure in which 14 are formed is used. And
The ends of the fixed legs 14 of the heat shield plate 7 are fixed to the left and right joint flanges 2b outside the heater unit 5 and the heat insulating material 6 with screws 15, and the plate surface portion 12 is used to fix the heater unit 5, Space 1b between the heating chamber 2 and the peripheral wall of the cabinet 1
Each upper side of (the space on the opposite side of the machine room 1a) is covered, and at the same time, the heat insulating material 6 is restricted in the left-right direction. Further, a pressing portion 16 formed by cutting and raising a part of the plate surface portion 12 downward in a substantially L shape is formed at an appropriate position of the plate surface portion 12, for example, at two central positions, and heat is provided when the shield plate 7 is installed. The material 6 is pressed from above to regulate the movement in the vertical direction.

Reference numeral 17 denotes a high voltage transformer installed in the machine room 1a.

When cooking with the heater unit 5 of the microwave oven, the shelf 18 on which food (not shown) is placed
After setting on the shelf support 19, 19, the operation part (not shown) is operated to turn on the heater 10. As a result, the heater unit 5 generates heat, and the top plate 2a of the heating chamber 2 is heated to a high temperature (500 to 700 ° C). Then, the food in the heating chamber 2 is heated by radiant heat, high temperature air, or the like.

Here, there is a concern that the temperature of the upper wall of the cainette 1 will increase considerably under the influence of the heat of cooking, but this is not the case.

That is, the shield plate 7 is composed of a plate surface portion 12 that shields the top plate 2a and the space 1b, and fixed legs 14 that are provided so as to project from a part of the plate surface portion 12. In other words, the shielding plate 7 reduces the heat transfer area between the top plate 2a of the heating chamber 2 and the plate surface portion 12, and at the same time, the space 1b.
Has a structure in which the flow (rise) of heat from the cabinet to the upper wall side of the cabinet 1 is controlled by the protruding plate surface portion. As a result, the heat transmitted from the top plate 2a to the plate surface portion 12 is reduced, and at the same time, the heat of convection flows on the back surface of the plate surface portion 12 without touching the upper wall of the cabinet 1, and the heat quantity of radiation to the upper wall of the cabinet 1 and It will reduce the heat of convection together. Of course, this is also because the protruding wall 13 formed on the peripheral edge of the plate surface portion 12 serves as a dam portion so that heat does not escape upward from below the plate surface portion 12.

For the above reason, the temperature rise in the upper wall can be suppressed and the cabinet 1 can be maintained at a low temperature. Of course, the temperature on the space 1b side can also be kept low. Moreover, since the fixed leg 14 is arranged outside the heater unit 5 and the heat insulating material 6, it is arranged from the heater unit 5, the heat insulating material 6 and the top plate 2a of the heating chamber 2 to the heat shield plate 7 through the fixed leg 14. The heat that reaches it is extremely low.
Therefore, the amount of heat transferred from the heat shield plate 7 to the upper wall side of the cabinet 1 is also significantly reduced, and as a result, the cabinet 1
The temperature of the upper wall is effectively suppressed.

As a result, the safety can be improved and, at the same time, the amount of heat leaked to the outside can be reduced, and the heating efficiency can be increased. Moreover, since the horizontal movement of the heat insulating material 6 is regulated by using the fixed legs 14 and the vertical movement is regulated by the pressing portions 16, 16,
This has the advantage of being able to hold the entire heat insulating material in a predetermined position without displacement, together with front and rear regulations, and preventing variations in the mounting position between products and variations in the heating performance (heating chamber 2 for the temperature set by the user). This has the effect of reducing the temperature shift).

In one embodiment, a part of the plate surface portion is cut and raised to form an L-shape to form the fixed leg and the pressing portion. However, a part of the plate surface portion is convexly formed (drawing) downward to form the fixed leg, You may make it form a pressing part.

[Effects of the Invention] As described above, according to the present invention, the heat shield plate and the protruding wall can prevent the rise of heat convection in the space between the cabinet and the heating chamber. At the same time, the amount of heat transferred to the heat shield plate through the fixed legs can be extremely reduced. Therefore,
The amount of heat transferred to the upper wall of the cabinet is greatly reduced, and as a result, the temperature of the upper wall of the cabinet is kept as low as possible.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention.
The figure is a front sectional view showing the structure around the heat shield plate, which is the main part,
The figure is a perspective view showing the appearance of the heat shield plate, Fig. 3 is a front sectional view showing the microwave oven to which the heat shield plate is applied, and Fig. 4 adopts a conventional heater unit, a heat insulating material and a heat shield plate. It is a front sectional view showing a microwave oven. 1 ... Cabinet, 2 ... Heating chamber, 5 ... Heater unit, 6 ... Heat insulating material, 7 ... Heat shield plate, 12 ... Plate surface part, 13
...... Projection wall, 14 ...... Fixed leg, 16 ...... Presser section.

Claims (3)

[Claims] 1. A heating chamber provided in a cabinet, a heater unit provided on an upper surface of a top plate of the heating chamber, a heat insulating material provided above the heater unit, and the heat insulating material from above. A heat shield plate that covers and projects into a space formed between the cabinet and the heating chamber; and a projecting wall that is provided at an end portion of the heat shield plate and projects downward. A microwave oven comprising a heater unit and fixing legs for fixing a heat shield plate to the heating chamber outside the heat insulating material. 2. The fixed leg is formed by projecting downward a part of a heat shield plate corresponding to both end faces of the insulating material on the heater unit.
The microwave oven described in the item. 3. The heat shield plate is provided with a holding portion for holding the heat insulating material from above as a part of the heat shield plate is formed so as to project downward. The microwave oven described in the item.