JPS6046800B2 - High frequency heating device - Google Patents

Description

Detailed Description of the Invention The present invention provides a high-frequency heating device that uses a rotating antenna to supply high-frequency energy into a heating chamber. The purpose is to eliminate unevenness and improve distribution performance.

Conventionally, an approximately L-shaped rotating antenna has been used because it is the simplest shape and easy to make, but the drawback of this rotating antenna is that it is a vertical electric field coupling type in which most of the radio waves are radiated from its vertical portion. Since there was very little radio wave radiation from the horizontal part, the rotation effect was not very good. Therefore, the present invention provides a discontinuous wall in the circumferential direction around the vertical portion of the rotating antenna, and the portion of the wall that faces the horizontal portion of the antenna is bent approximately at right angles in the radial direction. As the antenna rotates, a vertical electric field and a horizontal electric field are generated alternately between the antenna and the discontinuous wall, increasing the antenna rotation effect and improving the distribution performance. An embodiment of the present invention will be described with reference to the accompanying drawings. The heating cooker shown in FIG. 1 is a built-in type built in a sink, and four electric stoves 1 are arranged on the top surface of the cooker for cooking boiled food.

The electric stove 1 is controlled by a knob 2 provided on the front panel of the cooking device, and a control knob 3 of the cooking device is arranged on the same panel. A cooling intake/exhaust hole 4 is provided at the bottom of the control panel and above a door 6 having a handle 5.

Reference numeral 7 denotes a drawer provided below the main body of the cooker for storing small items such as attachments.

Next, in FIG. 2, the door 6 is of a pull-out type that slides on a rail 8, and a shelf 9 is provided on the inner surface of the door 6 on which foods and the like can be placed.

Therefore, when the door 6 is pulled out, the shelf 9 comes out, making it easy to put in and take out food, and is convenient to use. Reference numeral 10 denotes a heating chamber for cooking food; an upper heater 11 is provided above the heating chamber approximately parallel to the upper wall of the heating chamber, and a lower heater 11' is provided on the outer bottom wall of the heating chamber. .

Reference numeral 12 denotes a fan for circulating hot air provided at the rear of the heating chamber 10, which is used to uniformize the temperature distribution within the heating chamber.

Reference numeral 13 denotes a heat insulating material provided around the outer periphery of the heating chamber 10, which prevents heat dissipation from the outer wall of the heating chamber and improves thermal efficiency.

14 is a magnetron which is a high frequency oscillator, and has a configuration in which high frequency energy is transmitted through a Z-shaped waveguide 15, and one end of the waveguide 15 is connected to a power feeding port provided approximately in the center of the upper wall of the heating chamber 10. 16.

An L-shaped rotary antenna 17 is rotatably provided through the power feeding port 16, and the rotary antenna 17 is composed of a vertical portion 18 and a horizontal portion 19. Above antenna 1
One end of the vertical portion 18 of the waveguide 15 is connected to an antenna drive shaft 2 made of a low-loss dielectric material such as alumina porcelain.
0, the ± antenna drive shaft 20 penetrates the upper wall of the waveguide 15 and is fixed with a rotation shaft 21 and a Matsuba pin 22, and the rotation shaft 21 is a thrust shaft fixed to the outer wall of the waveguide 15. It is configured to rotate while rotating between it and the bearing plate 23, and its driving source is a motor 24, which is connected to a motor shaft 25 and a pin 26. Therefore, even if the centers of the motor shaft 25 and the rotary antenna 17 are slightly misaligned, they rotate smoothly.

A sealing plate 27 seals the power supply port 16 and is made of a low-loss dielectric to prevent hot air in the heating chamber 10 from passing through the waveguide 15 to the magnetron 14 .

Therefore, the rotary antenna 17 rotates using the sealing plate 27 and the upper wall of the waveguide 15 as bearings. A discontinuous wall 34 is provided around the vertical portion 18 of the rotating antennas 1 and 7 in the circumferential direction. The discontinuous wall 34 has its lower end substantially perpendicular to the radial direction above the horizontal portion 19 of the rotating antenna. Therefore, when the rotation angle is such that the horizontal part 19 of the rotating antenna faces this wall, a phenomenon occurs between the discontinuous wall 34 and the horizontal part 19 of the rotating antenna, as shown in Figure 3. At other rotation angles, a vertical electric field is generated between the discontinuous wall 34 and the vertical portion 18 of the rotating antenna, resulting in vertical excitation. In this way, the direction of the electric field generated between the discontinuous wall 34 and the rotating antenna 17 can be changed alternately between the vertical and horizontal directions as the antenna rotates, and furthermore, by the discontinuous wall, By intensifying the radio wave radiation from the horizontal portion of the antenna, the rotation effect of the antenna is enhanced and the distribution performance can be improved.

In addition, in the embodiment shown in FIG. 3, the discontinuous wall 34 is directly attached to an open wall, so there is no radio wave radiation from between these walls.
By providing an insulator or a space between them, it is possible to radiate some radio waves from this space as well. 3
2 is the cooling fan of the magnetron 14, and the air guide 3
The structure is such that air is taken in and exhausted from the air intake and exhaust hole 4 through the air intake and exhaust hole 3 .

In the above configuration, radio waves from the magnetron 14 pass through a Z-shaped waveguide 15 and are radiated into the heating chamber 10 from a rotating antenna 17 that is rotationally driven by a motor 24 .

The cooling air for the magnetron 14 enters through the intake/exhaust hole 4, cools the magnetron 14 by the cooling fan 32, and is discharged to the front through the intake/exhaust hole 4.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a high-frequency heating device showing an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the same, and Fig. 3A and b are enlarged cross-sectional views and bottom views of the high-frequency power feeding part of the same main parts. There is. 10... Heating chamber, 11... Upper heater,
14...Magnetron, 15...Z-type waveguide, 17
...Rotating antenna, 34...Discontinuous wall.

Claims (1)

[Scope of Claims] 1. A heating chamber, a high-frequency oscillator, a waveguide, and a rotating antenna that couples the heating chamber and the waveguide in a high-frequency manner, and the rotating antenna has an approximately L shape consisting of a vertical portion and a horizontal portion. A discontinuous wall is provided around the vertical portion in the rotational direction, and one end of the discontinuous wall facing the horizontal portion of the rotating antenna is bent at a substantially right angle in the radial direction. A high-frequency heating device characterized by: 2. The high-frequency heating device according to claim 1, characterized in that an insulator or a space gap is interposed between the discontinuous wall and the open wall surface.