JPH0793187B2 - High frequency heating device - Google Patents

Description

[Field of Industrial Application] High-frequency heating device is mainly used for heating food, and is commonly called a microwave oven. A heating device called a microwave oven is provided with a turntable for rotating the food. It is about how to.

2. Description of the Related Art Conventionally, there are a turntable method of rotating food and a stirrer method of rotating agitating blades of radio waves as a method for uniformizing the heating of food in the heating chamber. The turntable method is also a uniform heating method. This is a powerful method.

However, if the method of distribution is different due to the difference in the method of supplying high-frequency electromagnetic waves into the heating chamber and it is a bad method, the degree of heating at the center of rotation of the turntable becomes weaker than that of the area around the rotation, or conversely. It gets stronger.

As a method of supplying high-frequency electromagnetic waves of the turntable method, conventionally, high-frequency electromagnetic waves of a magnetron are guided to a waveguide, and the opening of the waveguide is arranged on the upper side of the heating chamber or on the side wall. The food was heated uniformly.

Problems to be Solved by the Invention However, thawing of frozen foods and the like requires a method with a higher degree of uniformity, and recently, a method with the lowest possible cost has been demanded.

In addition, a cover made of low-loss dielectric is provided in the opening of the waveguide to prevent food scraps from reaching the dipole antenna of the magnetron. When food debris adheres to the cover, if the food debris is abnormally heated and the cover is made of resin, the cover may melt or ignite. If the cover is made of ceramic, it may crack due to thermal strain.

Therefore, the present invention eliminates the above-mentioned conventional defects and further improves the performance of heating distribution.

 Eliminate the waveguide to reduce costs.

The strength of the electric field of the cover that seals the opening is weakened so that food dust does not become abnormal even if it adheres to the cover.

That is.

Means for Solving the Problems In order to achieve the above object, the present invention provides a recess in a part of a side wall of a heating chamber, and arranges the dipole antenna of a magnetron in the recess so that the dipole antenna is horizontal. The angle is changed, and the recess is covered with a cover made of a low-loss dielectric.

Action Regarding the inclination of the concave part, it is difficult to heat the center bottom of the food, so the inclination of the upper part is made larger than the inclination of the lower part, and the above-mentioned drawbacks are solved by radiating the high frequency electromagnetic wave from the dipole antenna obliquely downward. be able to.

Embodiment The present invention will be described based on an embodiment applied to a household microwave oven.

FIG. 1 is a front sectional view of an embodiment of the present invention. At the bottom of the heating chamber 2 in the main body 1, a turntable 3 for rotating food (not shown) or the like is provided. The turntable 3 is mounted on a roller 4 provided between the turntable 3 and the bottom wall of the heating chamber 2, and at the center of the turntable 3,
A pulley shaft 5 meshing with the turntable 3 penetrates the bottom wall of the heating chamber 2. A motor 6 for rotating the turntable 3 is arranged below the pulley shaft 5.

The magnetron 7 is located on the right side of the heating chamber 2.
With the dipole antenna 8 of the horizontal, the recess 9 of the heating chamber 2
It is located in. A cover 10 is provided between the recess 9 and the heating chamber 2 to prevent food scraps from adhering to the dipole antenna 8.

FIG. 2 is a sectional view of an essential part of FIG. In FIG.
A fixing plate 11 for mounting the magnetron 7 between the recess 9 and the magnetron 7 is welded to the side wall of the heating chamber,
The magnetron 7 is attached with bolts 12 and nuts 13. Further, the upper part of the fixing plate 11 is bent at a right angle and fixed to the flange of the wall of the heating chamber with the screw 14. This is because the side wall of the heating chamber 2 is not distorted by the gravity of the magnetron 7 when the main body falls. Inclination angle A of the upper wall 15 of the recess 9
Is larger than the inclination angle B of the lower wall 16. Therefore, the radiation direction of the high-frequency electromagnetic wave from the dipole antenna 8 of the magnetron 7 is radiated in the direction of arrow 17, that is, in the downward oblique direction, eliminating the weak tendency of the lower part of the food and making the degree of heating above and below the food uniform.

FIG. 3 is a sectional view taken along the line CC ′ of FIG. Rear wall of recess 9
The inclination angle D of 18 is larger than the inclination angle E of the front wall 19. Therefore, the radiation direction of the high-frequency electromagnetic wave from the dipole antenna 8 becomes the direction of the arrow 20, and the flatness of the food is uniformly heated.

EFFECTS OF THE INVENTION By adjusting the inclination angle of the concave portion, it is possible to adjust the degree of heating of the food vertically and horizontally, so that the food is heated uniformly.

Since there is no waveguide for supplying high frequency electromagnetic waves to the heating chamber, the cost can be reduced.

Since the electric field of the cover is weaker than the method of supplying high-frequency electromagnetic waves into the heating chamber through the opening of the waveguide, even if food is attached to the cover, it will not be abnormally heated or ignited.

[Brief description of drawings]

FIG. 1 is a front sectional view of an embodiment of the present invention, FIG. 2 is an enlarged view of an essential part of the same, and FIG. 3 is a sectional view taken along the line CC ′ of FIG. 2 ... Heating chamber, 9 ... Recess, 15 ... Upper wall, 16 ... Lower wall,
18 …… rear wall, 19 …… front wall.

Claims (5)

[Claims] 1. A heating chamber for heating an object to be heated in a main body, and a turntable for rotating the object to be heated in the heating chamber,
A magnetron for generating high-frequency electromagnetic waves is provided, the magnetron has a dipole antenna, the sidewall of the heating chamber is arranged so that the dipole antenna is horizontal, and the heating chamber has a recess near the dipole antenna portion. A high-frequency heating device formed so as to cover the recess with a cover made of a low-loss dielectric. 2. The high frequency heating apparatus according to claim 1, wherein the shape of the recess is asymmetric with respect to the dipole antenna. 3. The high frequency heating apparatus according to claim 2, wherein the lower portion of the recess has a smaller inclination than that of the upper portion. 4. The high-frequency heating device according to claim 2, wherein the recesses have different inclinations in the front-rear direction. 5. The high frequency heating apparatus according to claim 4, wherein the slope of the recess is smaller in the front part than in the rear part.