JPS59189590A - 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 The present invention provides a high-frequency heating device that supplies high-frequency energy into a heating chamber using an antenna such as a rotating antenna.
It prevents the sealing plate that seals the coupling hole between the heating chamber and the antenna from getting dirty, and prevents sparks caused by the sealing plate becoming dirty.
This reduces the problem of the lower output image to one level.

The area near the coupling hole in the heating chamber is generally very dense and when the reflection coefficient is high, such as during light loads, sparks may occur between the coupling hole in the heating chamber and the antenna. When the seal is sealed with a dielectric material such as, electric lines of force tend to concentrate on this dielectric material, and sparks are extremely likely to occur, especially when the surface of the seal portion is contaminated with food particles, oil, etc. Conventionally, in order to prevent this problem, the shape of the sealing part has been proposed to make the creepage distance between the antenna and the end face of the heating chamber coupling hole as large as possible, but if the sealing plate becomes extremely dirty, the creepage distance must be increased slightly. Even if you do so, it is not possible to completely prevent sparks.

In particular, when using a high-frequency heating device that also uses a heater, the saw oil that is scattered during cooking becomes carbonized by the heat of the heater and sticks to the surface, so if you neglect cleaning the heating chamber a little, it becomes very easy to spark. Furthermore, if the surface of the sealing plate becomes contaminated with carbide, the operating point of the magnetron may change, causing problems such as lower output images. Therefore, the present invention has a structure in which a contamination prevention plate for the sealing plate is installed concentrically with the antenna directly under the sealing plate, so that oil etc. splashed from food do not contaminate the sealing plate.This prevents problems such as sparks and output reduction. It is completely prevented.

An embodiment of the present invention will be described below with reference to the drawings.

The heating cooker shown in Fig. 1 is a built-in type that is installed in the sink, and four electric stoves 1 are arranged on the top of the second part so that it can be used to cook stews. 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. Reference numeral 4 denotes a cooling intake/exhaust lamp located 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 the inner surface of the door 6 is provided with a shelf 9 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 take food in and out, and is convenient to use.

Reference numeral 10 denotes a heating chamber for cooking food, and an upper heater 11 is provided above the heating chamber substantially 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, which is provided at the rear of the heating chamber 10, and serves to even out the temperature distribution within the heating chamber. 13
is a heat insulator 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 via a type 2 waveguide 15;
One end of the heating chamber 10 is connected to a connecting port 16 provided approximately in the middle of the earthen wall of the heating chamber 10. An L-shaped rotary antenna 17 is rotatably provided through the connecting port 16. The rotating antenna 17 is made up of a vertical part 18 and a horizontal part 19. One end of the vertical part 18 of the antenna 17 is connected to an antenna drive made of a low-loss dielectric material such as alumina porcelain in the waveguide 15. The antenna drive shaft 20 passes through the upper wall of the waveguide 16 and is fixed with a rotating shaft 21 and a matsuba pin 22, and the rotating shaft 21 is a thrust shaft fixed to the outer wall of the waveguide 15. It is configured to rotate without sliding between it and a 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, the structure rotates smoothly.

A sealing plate 27 seals the coupling 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 and reaching the magnetron 14. Therefore, the rotary antenna 17 rotates using the sealing plate 27 and the earth wall of the waveguide 15 as bearings.

In the part of the vertical part 18 of the rotating antenna on the heating chamber side,
A stain prevention plate 28 for the sealing plate is arranged opposite to the sealing plate 27. This is due to the fact that if oil, etc. that scatters from the food hits the sealing plate and changes there, a situation similar to a short circuit between the antenna and the heating chamber will occur through this surface, causing sparks and a drop in output. This is to prevent problems from occurring.

Since the dirt prevention plate 28 is smaller than the diameter of the sealing plate, there is a possibility that the outer periphery of the sealing plate may become dirty, but the important point is that there should be a completely clean insulating layer between the antenna and the end of the heating power supply port. There is no need to make the diameter of the dirt prevention plate larger than the diameter of the sealing plate.

Further, since the operating point of the magnetron is also changed by changing the diameter of the dirt prevention plate, it is possible to adjust the operating point to an optimum state by completely changing the dimension of this diameter.

Considering that the purpose of the anti-fouling plate is simply to prevent the sealing plate from getting dirty, it is possible to attach it to the heating chamber side instead of attaching it to the antenna 11III as in this embodiment.In that case, the anti-fouling plate can be attached to the outer conductor of the coaxial line. In order to perform the same function as the antenna, the high frequency loss between the antenna and the dirt prevention plate increases and the effective length of the antenna inside the oven changes.
Furthermore, it is necessary to increase the length of the vertical part of the antenna.
A major drawback arises in that the size of the effective height within the fractional heat chamber is reduced.

As explained above, according to the present invention, by using a simple structure and completely preventing dirt on the sealing plate, sparks,
It has very great effects, such as preventing problems such as a drop in output, and at the same time being able to be used to adjust the operating point by changing the dimensions of the dirt prevention plate.

Moreover, it solves the problems that may occur when trying to obtain the same effect using other methods, and is practical and highly effective.

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 of the magnetron 14 enters through the intake/exhaust hole 4, and the cooling fan 32 cools the magnetron 14.
It is discharged more to the front.

[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 sectional view of the same, and FIG. 3 is an enlarged sectional view of the same essential parts. 10... Heating chamber, 14... Magnetron,
16... Waveguide, 16... Coupling hole, 1
7... Antenna, 28... Dirt prevention plate, 2
Completed... Sealing board. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 /3

Claims (1)

[Claims] a heating chamber; a high-frequency oscillator; a waveguide for transmitting high-frequency energy oscillated by the high-frequency oscillator to the heating chamber; an antenna for high-frequency coupling between the waveguide and the heating chamber; and a sealing plate made of a dielectric material that closes a coupling hole with the antenna provided in the tube and the heating chamber, and the antenna has a dirt prevention plate of the sealing plate at a position opposite to the sealing plate. A high-frequency heating device characterized by: