JPS62202489A - Antenna rotating apparatus in microwave oven - 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 aims to solve the following problems.

(Industrial Application Field) The present invention relates to a motor for rotating an antenna used in a high-frequency transmitter installed in the ceiling of a microwave oven.

(Prior art) The output shaft of the geared motor that rotates the antenna used in microwave ovens is made of metal, and the output shaft is coated with Teflon resin to prevent radio waves from propagating to the output shaft. It is sometimes covered with However, if the metal output shaft itself receives radio waves due to leaking radio waves, and the output shaft itself is not grounded to the gear box, or even if the gear box itself is grounded to the range body, there is a gap between the output shaft and the gear box. If the grounding condition of the gear box is not satisfied and the insulation state is not satisfied, the output shaft is charged, and when the unstable insulation state is broken and the output shaft and the range body are grounded, it is discharged and the inside of the gear box is There was a problem with abnormally high temperatures.

Furthermore, the output shaft itself reflects the radio waves and enters the gear box, irradiating the radio waves to the resin gear or lubricating oil inside, and the resin gear or lubricating oil absorbs the radio waves and generates heat, causing the gear to deform. There was a problem with poor engagement. To solve this problem, we tried forming the output shaft using a resin such as Duracon resin (polyacetal resin), but as the usage time passed, the resin-molded shaft became hot and weakened, causing the antenna to malfunction. A problem occurred where it became difficult to maintain rotation.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems, and not only can sufficient strength be obtained at room temperature, but the temperature of the shaft does not rise even when used for a long time. It is an object of the present invention to provide an antenna rotation device for a microwave oven in which the material of the output shaft is set so as to avoid the conventional drawbacks such as high frequency reflection.

The configuration of the present invention is as follows.

Means for Solving Problem C) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Function) By rotating the motor shaft of the motor, the antenna is rotated while maintaining the state in which its inlet overlaps with the outlet of the waveguide. In this state, the high-frequency waves sent out from the high-frequency oscillator pass through the waveguide and enter the antenna through the outlet of the waveguide and the inlet of the antenna. It is then diffusely distributed through the antenna into the microwave housing.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. In FIGS. 1 to 4, reference numeral 1 denotes a housing of a microwave oven, which is made of a metal material.

In the ceiling part 2, 3 is a top plate and 4 is a partition plate, both of which are made of metal material. Reference numeral 5 denotes holes for extracting high frequency waves, and a large number of holes are provided along the rotation locus of the emission port in the antenna, which will be described later. Next, 6 indicates a waveguide. This waveguide is composed of a waveguide element 7 attached to the top plate 3 and a waveguide section 8 formed by a part of the top plate 3. The internal dimensions Δ and B of the waveguide 6 are respectively formed to be 174 (for example, about 301 cm) and 1/8 (for example, about 151 m) of the high frequency fundamental wavelength. Reference numeral 9 denotes a high frequency oscillator attached to one end of the waveguide, for example, a magnetron is used, and its transmitter 10 is located within the waveguide 6. Reference numeral 11 indicates a high-frequency output port provided at the other end of the waveguide 6, which is formed in the shape of a round hole.Next, 14 is an antenna, which is formed in a planar fan shape using a metal material such as aluminum. be. 15 indicates an inlet, and the outlet 11
and are arranged in a polymerized manner.

16 indicates a discharge port. Reference numeral 17 denotes a steadying piece attached to the antenna 14, which is made of a resin material with a low friction coefficient of 5, such as tetrafluoroethylene, and is adapted to slide along the upper surface of the partition plate 4. A connecting sleeve 18 is fixed to the antenna 14 and is made of a conductive material such as aluminum, and is provided so as to pass through the inlet 15. Next, reference numeral 19 indicates a mounting frame attached to the waveguide element 7. Reference numeral 20 denotes a motor for rotating the antenna, which is attached to the mounting frame 19 using an upper fitting 23. In this motor, 21.22
indicates a case, which is made of a resin material such as PBT resin and a metal material such as an iron plate. 24 is a bearing formed in a part of the case 21, and 25 is a bearing attached to the case 22, which is made of a resin material. 26 are bearings 24 and 25
The motor shaft attached to the motor shaft is made of a resin that has a low loss coefficient (permittivity, dielectric loss tangent) at high frequencies and whose loss coefficient decreases as the temperature rises, such as tetrafluoroethylene resin (glass fiber may also be included). and the waveguide 6
It is positioned so as to pass through the outlet 11 of the antenna 14 and the inlet 15 of the antenna 14. The connecting sleeve 18 is fixed to the motor shaft 26 (the shaft 26 is press-fitted into the sleeve 18). The gap between the waveguide element 7 and the tip of the sleeve 18 constitutes a radio wave tip, and its dimension C should be as narrow as possible in order to reduce high frequency leakage.
and to reduce sparks between the sleeve and the waveguide element 7 (
In order to achieve this, the wider the better, and in consideration of both, the dimension is set to, for example, 0.7, which is between 1/128 and 1/256 of the fundamental wavelength of the high frequency. Also, the distance between the outer circumferential surface of the sleeve 1B and the hole edge of the outlet 11 is 1/1 of the above fundamental wavelength.
It is set to 16. 27 is the motor body, and the stopper 28
It is fixed to the case 21 using. Reference numeral 29 denotes a speed reduction gear provided inside the case, and is made of heat-resistant resin, such as polyacetal resin. Reference numerals 30 and 31 designate a pair of transmission elements formed on the gear 29 and the motor shaft 26, which are configured to transmit rotational force when they are engaged with each other as shown in FIG.

With the above configuration, when the microwave oven is operated, the motor main body 27 operates and its rotational force is transferred to the gear 2 for deceleration.
9 to the motor shaft 26, and the shaft 26 rotates. The rotational force is applied to the antenna 14 through the sleeve.
is transmitted, and the antenna 14 rotates. In this case, since the steady plate 17 slides along the top surface of the partition plate 4, the antenna 14
Vertical vibration is prevented.

In the state where the antenna 14 rotates as described above,
A high frequency wave is emitted from the transmitting section 10 of the high frequency oscillator 9, and the high frequency wave passes through the inside of the waveguide 6, passes through the outlet 11 of the antenna 14, and reaches the inside of the antenna 14 through the inlet 15 of the antenna 14. Further, the high frequency waves are emitted from the outlet 16 and diffused into the housing 1 through the multiple holes 5.

In this case, even if the high frequency waves leak from the radio wave choke section and reach the motor shaft 26, since the motor shaft 26 has a small loss coefficient, the electric power absorbed by the motor shaft 26 is small, and almost no heat is generated. Also, even if it starts to heat up, the motor shaft 26
Since it is made of a resin whose loss coefficient decreases as the temperature rises, the loss coefficient further decreases and the temperature rise is prevented.

Next, FIGS. 5 and 6 show examples in which motors with different structures are used. In the figure, 33 and 34 indicate cases, both of which are made of metal material (iron plate).

In the motor body 27e of this motor 20e,
35 is the rotor shaft fixed to case 33, 36 is case 3
A magnetic scraper piece is formed by cutting and raising a part of 3, 37 is a coil, 38 is a coil cover, and 39 is a rotor, which is rotatably attached to the rotor shaft 35.

In this configuration, the motor main body 27e is disposed on the side of the motor shaft 268, and the two are connected by a deceleration gear 29e arranged horizontally, so that the top of the microwave oven is The height dimension from the plate 3e to the upper surface of the motor 2oe (the upper surface of the case 34) can be reduced. For example, the dimension E shown in FIG.
The step dimension F of the step portion 41 at point e can be made comparable to or smaller than that, and as a result, the motor 20e can be housed between the top plate 3e and the upper surface of the waveguide 6e.

It should be noted that parts that are functionally the same or equivalent to those in the previous figure are given the same reference numerals as in the previous figure with an alpha character e, and redundant explanations are omitted.

(Effects of the Invention) As described above, in the present invention, the waveguide 6 is provided on the ceiling of the housing 1, and a high frequency is transmitted from the high frequency oscillator 9 provided at one end of the waveguide.
Since the antenna rotated by the motor 2o is distributed into the housing via the outlet 11 and the inlet 15 of the antenna 14, the high frequency emitted from the high frequency transmitter is diffused into the housing. It has the effect of uniformly distributing the heating effect on the processed material within the housing.

Furthermore, since the center of rotation of the antenna 14 is supported by the motor shaft 26 passing through the outlet 11 and the inlet 15, the overlapping state of the outlet 11 and the inlet 15 is determined in the rotational shape f of the antenna. Even if the antenna rotates, all of the high frequency waves emitted from the outlet 11 are directed toward the inlet 15, which has the effect of preventing direct leakage to the outside.

Furthermore, even if the motor shaft 26 is passed through the overlapping portion of the outlet port 11 and the inlet port 15, the motor shaft is made of a resin having a low loss coefficient and whose loss coefficient decreases as the temperature rises. Since the motor shaft 26 is formed in such a way that the temperature does not easily rise even when subjected to the above-mentioned high frequency, and even if the temperature of the motor shaft 26 rises slightly, its loss coefficient further decreases and the temperature rise is prevented by itself. This has the effect of self-preventing the strength of the shaft 26 from decreasing due to temperature rise, and has the revolutionary effect of being able to be used for a long life.

The RFJ fancy explanatory drawings in Drawing 41 show the embodiment of the present application, and Fig. 1 is a longitudinal cross-sectional view showing the relationship between the upper part of the housing, the waveguide, the antenna, and the antenna rotation motor in a microwave oven, and Fig. 2 3 is an exploded perspective view of the antenna rotation motor, FIG. 3 is an exploded perspective view showing the relationship between the waveguide and the motor, FIG. 4 is a perspective view showing the antenna separated from the waveguide, and FIG. 5 and FIG. 6 show different embodiments, FIG. 5 is an exploded perspective view of the motor, and FIG. 6 is a perspective view showing the relationship between the waveguide and the motor.

DESCRIPTION OF SYMBOLS 1... Housing, 6... Waveguide, 9... High frequency oscillator, 11... Hole exit, 14... Antenna, 15
...Inlet, 20...Motor, 26...Motor shaft.

Figure 2 Figure 3 g

Claims (1)

[Claims] The ceiling of the microwave oven housing is equipped with a waveguide equipped with a high-frequency oscillator at one end and a high-frequency outlet at the bottom of the other side, and below the waveguide is a waveguide that emits radio waves emitted from the outlet. The antenna is provided with an antenna for diffusively distributing the waves into the housing interior, and the antenna has a high frequency inlet on the upper surface, and the inlet is positioned to overlap with the outlet of the waveguide, while A motor shaft of a motor fixedly provided to the housing is positioned so as to pass through the outlet and the inlet, and an antenna is attached to the motor shaft, with the outlet and the inlet overlapping each other. In a microwave oven, the antenna is coupled in a rotational position, and the motor shaft is made of a resin having a low loss coefficient against high frequencies and whose loss coefficient decreases as the temperature rises. Antenna rotation device.