JPS5942795A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high frequency heating device in which a rotating antenna is provided in a heating chamber.

Conventional structure and its problems In a conventional microwave oven, which is a high-frequency heating device, for example, a stirrer fan is installed in the heating chamber to stir the radio waves as a way to equalize the distribution characteristics of the high-frequency waves supplied into the heating chamber. Alternatively, there are methods such as rotating the mounting table on which the object to be heated is placed, or rotating the radio wave radiator, that is, the antenna. Among these methods, the method of rotating the antenna increases the effective volume in the heating chamber. Because it can be used in large quantities, it is often used in household microwave ovens.

However, when a rotating antenna is installed at the top of the heating chamber, the distance between the antenna and the object to be heated is relatively short, so the heating characteristic of heating the object in the heating chamber by the radio waves radiated from the antenna is limited to the antenna. This is determined by the combination of the dimensions and shape of the antenna and heating chamber. That is, there is no common antenna that can be used in heating chambers with various different conditions, and it is necessary to design an optimal antenna each time the conditions of the heating chamber change.

In the past, many shapes of rotating antennas and power feeding methods using rotating antennas have been invented and devised, but the rotating antennas that have been implemented do not heat the central part of the heating chamber approximately evenly. When placed in a container and placed close to the center of the antenna and radiating high frequency waves, the
The temperature of one part of the body becomes extremely lower than the other,
Alternatively, in the case of fried eggs, uneven heating occurred where the outer periphery was overheated and the center was raw.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a high-frequency heating device capable of evenly dielectrically heating an object to be heated housed in a heating chamber.

Structure of the Invention In order to achieve the above object, the high frequency heating device of the present invention has the following features:
A rotating antenna that couples the waveguide and the heating chamber at high frequency is composed of a vertical component and a horizontal component, and the horizontal component is connected to the vertical component near an arbitrary corner on a substantially triangular plane. The configuration is such that the total length of the perpendicular line facing the connection point and toward the connection point and the vertical component protruding into the heating chamber is an integral multiple of the difference in wavelength used, and the This has the effect that the object to be heated can be dielectrically heated substantially uniformly and efficiently.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, reference numeral 1 denotes a main body of a high-frequency heating device, and a door 3 is provided at the opening of a heating chamber 2 provided in the main body 1 so as to be openable and closable. Reference numeral 4 denotes a heater plate provided in the second part of the main body 1. When boiling food etc. using this heater plate 4, the electric power for the plate heater 6 shown in FIG. Each is configured to be controllable. Reference numeral denotes an operation knob B that controls the output of a heater provided in the heating chamber 2 and a magnetron 8 used as an example of a high-frequency generator.

In FIG. 2, reference numeral 9 denotes a plate made of a heat-resistant dielectric material provided above the plate heater 6. As shown in FIG. 10 is a heater provided at the top inside the heating chamber 2, and 11 is a heater provided at the bottom of the heating chamber outside the heating chamber 2. The inside of the heating chamber 2 can be efficiently heated by the heaters 10 and 11. 12 is a heat insulating material provided around the outer periphery of the heating chamber wall 13. Reference numeral 14 denotes a Theno ζ-shaped waveguide that transmits the high frequency waves generated by the magnetron 8 into the heating chamber 2 . Reference numeral 15 denotes a rotating antenna that is provided facing into the heating chamber 2 by penetrating the waveguide 14 and the heating chamber 1 wall 16, and has a vertical component 17 that is approximately perpendicular to the heating chamber soil wall 16, and a substantially horizontal component 17 that is approximately perpendicular to the heating chamber soil wall 16. horizontal component 18. This rotating antenna 16 is connected to a drive shaft 19. It is rotated by a motor 23 via a belt 20 and pulleys 21,22.

FIG. 3 is a perspective view showing only the rotating antenna 15 taken out.

The hydrated component 18 of this rotating antenna 15 has a triangular planar shape, and is combined with the vertical component 1 in the vicinity of one corner.
The total dimension of the length L of the perpendicular line from the joint of the vertical component 17 to the opposite side and the portion of the vertical component 17 protruding into the heating chamber 2 is the wavelength used, 'P' or an integral multiple thereof. Furthermore, the dimension ratio between the negative iJi self-perpendicular line and the vertical component 17 protruding into the heating chamber 2 is set at a ratio of 2:1. Reference numeral 24 denotes protrusions provided on the left and right sides opposite the joint portion with the vertical component 17. The width of this protrusion 240 is approximately 1 of the wavelength used.
//6, the length is set to about 1/15 or less of the wavelength used.

The functions and effects of the above configuration will be explained below.

In order to have the effect of the rotating antenna 16 that radiates high frequency waves, it is important to increase the radio wave radiation ratio from the horizontal component, but by making the horizontal component 18 triangular, it is possible to use multiple In order to create a non-uniform horizontal electric field radially in the direction, the electric field force in the horizontal direction is suspended, and the amount of radio wave radiation from the horizontal component 18 is increased.

Also, the vertical component 1 of the rotating antenna 15 in the heating chamber 2
By making the total dimension of 7 and the horizontal component 7 equal to or an integral multiple of the wavelength used, it is possible to excite a wave of half a wavelength or more from the waveguide 14 to the rotating antenna 15 without being distorted. Radio waves can also be efficiently radiated into the heating chamber 2 from the vertical component 17 and horizontal component 18 of the rotating antenna 15.

Also, the vertical component 1 of the rotating antenna 160 in the heating chamber 2
7 and the horizontal component 18 to approximately 1:2, in addition to the triangular effect of the horizontal component 18, the ratio of the amount of radio wave radiation from the horizontal component 18 can be further increased.

As a result of checking the distribution state of high frequencies using various rotating antennas, we found that by setting the length ratio of the horizontal component 18 and the vertical component 17 protruding into the heating chamber 2 to 2:1, the heating chamber 2
It was confirmed that the degree of heating in the center area was increased.

Furthermore, by providing the protrusions 24 at both ends of the opposite side of the coupling part with the vertical component 17, a certain degree of local electric field concentration can be obtained in this part, and by rotating this strong electric field part, the effect of the rotating antenna 15 is is further improved, and the uniformity of heating, especially in the central portion of the heating chamber 2, is improved. However, since radio waves are absorbed from the outside of the food toward the center, the electric field distribution at the center is made stronger7 than around it, so that it is heated exactly evenly, but if the length of the protrusion 24 is If the length is too long, the electric field distribution at the center tends to weaken somewhat, so this length should be 1/15 or less of the wavelength used, and the width of the protrusion 240 should be approximately 1/1/1 of the wavelength used. /6 gave the best results.

FIG. 4 shows another embodiment of the horizontal component 18 of the rotating antenna 16, in which it is configured in a scalene triangle shape, and the same effect as described above can be obtained.

Effects of the Invention As described above, according to the high-frequency heating device of the present invention, the high-frequency waves from the high-frequency oscillator can be radiated into the heating chamber from the vertical and horizontal components of the rotating antenna through the waveguide. The electric field characteristics at the center of the heating chamber, where heating tends to be uneven, are improved, and the object to be heated can be heated approximately evenly.

[Brief explanation of the drawing]

1 is a perspective view of a high-frequency heating device according to an embodiment of the present invention, FIG. 2 is a front sectional view of FIG. 1, and FIG. 3 & is a perspective view of the rotating antenna shown in FIG. FIG. 3 is a plan view showing the horizontal component shown in FIG. 3, and FIG. 4 is a plan view showing another embodiment of the water V component shown in FIG. 1...Main body, 2...Heating chamber, 14...
... Waveguide, 16 ... Rotating antenna, 17
...Vertical component, 18...Horizontal component. Agent's name Patent attorney Toshi Nakao 4='t or 1
Figure 1 Figure 2 Figure 3 (OL) (b) Figure 4

Claims (6)

[Claims] (1) Consisting of a heating chamber that accommodates the object to be heated, a waveguide that guides high-frequency waves from a high-frequency oscillator into the heating chamber, and a rotating antenna that couples the waveguide and the heating chamber in a high-frequency manner. , the rotary antenna is composed of a vertical component that is substantially perpendicular to the upper wall surface of the heating chamber to which the rotary antenna is attached, and a horizontal component, and the horizontal component is composed of a vertical component that is substantially perpendicular to the upper wall surface of the heating chamber to which the rotary antenna is attached, and a horizontal component that is substantially perpendicular to the upper wall surface of the heating chamber, and the horizontal component is composed of a vertical component that is substantially perpendicular to the upper wall surface of the heating chamber to which the rotary antenna is attached. A high frequency that connects to the vertical component, faces this connection point, and has the total length of the vertical line toward the connection point and the vertical component protruding into the heating chamber as an integer multiple of approximately the diagonal of the wavelength used. heating device. (2) The high-frequency heating device according to claim 1, wherein the ratio of the length of the vertical line of the horizontal component to the length of the vertical component of the rotating antenna is 2:1. (3) The high-frequency heating device according to claim 1, wherein a plurality of protrusions are provided at a point on a side opposite to a connection point of the vertical component. (4) One protrusion is provided at each end of the side opposite to the connection point of the vertical component.
The high-frequency heating device described in Section 1. (5) The high-frequency heating device according to claim 1, wherein the width of the protrusion provided on the horizontal component of the rotating antenna is approximately 1/6 of the wavelength used. (6) The high-frequency heating device according to claim 1, wherein the length of the protrusion provided on the horizontal component of the rotating antenna is 1/15 or less of the wavelength used.