JPS62249385A - Antenna rotating apparatus of 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 Field of Application) The present invention relates to an antenna rotation device used in a high frequency transmitter installed in the ceiling of a microwave oven.

(Prior Art) In a microwave oven, in order to evenly distribute high frequency waves within the oven, an antenna provided on the ceiling of the microwave oven is rotated by a motor drive mechanism disposed above the antenna. However, since a four-wave tube is installed above the antenna to guide the high-frequency waves from the high-frequency oscillator to the antenna, the drive mechanism must be installed above it, and as a result, the above-mentioned drive mechanism must be installed above it. There was a problem in that the bulkiness increased, leading to an increase in the height dimension of the microwave oven.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems, and even if the antenna is rotated by a motor drive mechanism, the upward bulk can be reduced, and the microwave oven An object of the present invention is to provide an antenna rotation device for a microwave oven that can reduce the height dimension of the antenna.

The configuration of the present invention is as follows.

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

(Function) By rotating the output shaft of the motor-type drive mechanism, 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, l 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, reference numeral 6 indicates a waveguide, and 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 A and B of the waveguide 6 are respectively 122.4 im in the case of flat frequency fundamental wavelength (for example, 2450 M) Iz.
), which is 1 of the even-numbered bones (for example, about 301) and 1
78 (for example, approximately 15 cranes). Reference numeral 9 denotes a high frequency oscillator attached to one end 6a of the waveguide, for example a magnetron is used, and the oscillator 10 thereof is located within the waveguide 6. Reference numeral 11 denotes a high frequency outlet provided at the other end 6b of the waveguide 6, which is formed in the shape of a round hole with a diameter of 174 corresponding to the fundamental wavelength. Next, reference numeral 14 denotes an antenna, which is made of a metal material such as aluminum and formed into a fan-shaped planar shape. Reference numeral 15 denotes an inlet, which is arranged to overlap with the outlet 11.

16 indicates a discharge port. The distance E between the bottom plate 14m and the top plate 3 in this antenna is set to 178 of the fundamental wavelength.

Reference numeral 17 denotes a steadying piece attached to the antenna 14, which is made of a heat-resistant resin material with a low coefficient of friction 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 an electrically sensitive 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 indicates a motor drive mechanism for rotating the antenna, which is attached to the mounting frame 19 using a fastener 23. This motor drive mechanism 20
is the output section 20a mounted on the other end 6b of the waveguide 6.
and a driving section 20b connected to the output section 20a on the side opposite to the one end 6a of the waveguide.

As shown in the figure, the upper surfaces of the output section 20a and the driving section 20b are both located lower than the upper surface of the one end 6a of the waveguide 6 (they may be equal to each other), and the driving section is lower than the lower surface of the output section 20a. The lower surface of 20b is located close to the upper surface of the top plate 4. In the mechanism 20, 21 and 22 indicate a case, which is made of a metal material such as an iron plate. 24 is a bearing formed in a part of the case 21 in the output section 20a, and 25 is a bearing also attached to the case 22, which is made of a resin material. Reference numeral 26 denotes an output shaft attached to bearings 24 and 25, which is made of a resin having 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 included (The antenna may be reinforced by inserting a 4-wave tube), and is positioned so as to pass through the outlet 11 of the four-wave tube 6 and the inlet 15 of the antenna 14. The connecting sleeve 18 is fixed to the output 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 choke part, and its dimension C should be as narrow as possible in order to reduce high frequency leakage.
In addition, in order to reduce sparks between the sleeve and the waveguide element 7, the wider the better, and in order to balance both, for example, a dimension between 1/128 and 1/256 of the fundamental wavelength of the high frequency, for example 0.7 mm. is set to Further, the distance between the outer peripheral surface of the sleeve 18 and the hole edge of the outlet port 11 is set to, for example, 1/16 of the fundamental wavelength. Reference numeral 26a denotes an output gear provided in the output section 20a, to which the upper end of the output shaft 26 is connected. In the connection part, 30.31 is the gear 26
a pair of transmission elements formed on the output shaft 26 and the third transmission element;
As shown in the figure, the structure is such that rotational force can be transmitted in a mutually engaged state. Next, 27 is the driving part 20b
Shows the motor equipped with. In this case, 35 is a rotor shaft fixed to the case 22, 36 is a magnetic pole piece formed by cutting and raising a part of the case 22, 37 is a coil, 38 is a coil cover, and 39 is a rotor rotatable around the rotor shaft 35. It is installed. Next, 29 is a gear train for deceleration provided between the motor 27 and the output gear 26a, and is composed of a plurality of gears each made of a heat-resistant resin such as polyacetal resin and arranged side by side in the horizontal direction. A gear 29a at one end of the gear train 29 meshes with a binion 39a integral with the rotor 39, and a gear 29b at the other end meshes with the output gear 26.
It is meshed with a.

With the above configuration, the motor drive mechanism 20 is activated when the microwave oven is activated. The rotational force of the rotor 39 is transmitted to the pinion 39a, the gear train 29 for M speed, and the output gear 2.
6a to the output shaft 26, and the shaft 26 rotates. The rotational force is transferred to the antenna 14 through the sleeve 18.
is transmitted, and the antenna 14 rotates.

In this case, since the steadying piece 17 slides along the upper surface of the partition plate 4, vertical vibration of the antenna 14 is prevented. In the state where the antenna 14 rotates as described above, high frequency waves are emitted from the transmitter 10 of the high frequency transmitter 9, and the high frequency waves pass through the inside of the waveguide 6 and exit from the outlet 11 to the inlet 15 of the antenna 14. and reaches the inside of the antenna 14. Further, the high frequency waves are emitted from the outlet 16 and distributed diffusely into the housing 1 through the plurality of holes 5. The high frequency waves distributed within the housing 1 heat the object (food) 42 on the saucer 41 in a well-known manner.

In the above case, even if the high frequency waves leak from the radio wave choke section and reach the output shaft 26, the output shaft 26 has a small loss coefficient, so the power absorbed by the output shaft 26 is small, and almost no heat is generated. Even if it begins to generate heat, the output shaft 26 is made of a resin whose loss coefficient decreases as the temperature rises, so the loss coefficient further decreases and the temperature rise is prevented. .

Next, FIG. 4 showing another embodiment of the present application will be described.

This figure shows an example in which the height dimension of the waveguide is different from that of the previous embodiment, in which dimensions F and G are set to 178 and 1/16 of the high frequency fundamental wavelength, respectively.

In addition, the height of the output section 20ae is made almost the same as the difference in height between the one end 5ae and the other end 6be of the waveguide, and the lower surface of the driving section is positioned with almost no clearance from the upper surface of the top plate 3e. There is. By doing so, the height of the microwave oven can be made much lower than in the case shown in FIG.

In addition, for parts d that are considered to have the same or equivalent configuration as the previous one, the same reference numerals as the previous one are appended with the letter e, and redundant explanations are omitted.

(Effects of the Invention) As described above, in the present invention, a four-wave tube 6 is provided on the ceiling of the housing 1, and a high frequency is transmitted from a high frequency oscillator 9 provided at one end of the waveguide, and a high frequency wave is emitted from the outlet. 11. Since the antenna rotated by the motor drive mechanism 20 is distributed into the housing via the inlet 15 in the antenna 14, the high frequency waves emitted from the high frequency transmitter are distributed into the housing. It is distributed diffusely and has the effect of providing a uniform heating effect to the processed material within the housing.

Furthermore, the center of rotation of the antenna 14 is supported by the output shaft 26 passing through the outlet 11 and the inlet 15. Therefore, in the rotating state of the antenna 14, the outlet 11 and the inlet 150 overlap each other. can be maintained,
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.

Moreover, as mentioned above, the antenna 1 is
4, the height of the other end 6b of the waveguide 6 is set to 1 of the even numbered bones of the height of the one end 6a as described above.
On the other hand, the thickness of the case in the motor drive mechanism is made larger on the morph side than the I7 dimension in the output shaft direction on the output shaft side, and the output shaft side of the case is The waveguide is mounted on the other end of the waveguide in an overlapping manner, and the motor side is located away from the other end of the waveguide, and the top surface of the case is mounted on the waveguide on both the output shaft side and the motor side. Since it is positioned at the same level or lower than one end of the tube so as not to protrude from the upper surface, it is possible to reduce the height of the microwave oven.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and Fig. 1 is a longitudinal sectional view showing the relationship between the housing, waveguide, antenna, and motor drive mechanism in a microwave oven, and Fig. 2 is a longitudinal sectional view showing the relationship between the waveguide and the motor drive mechanism. FIG. 3 is an exploded perspective view of the motor drive mechanism, and FIG. 4 is a longitudinal sectional view showing another embodiment in which the dimensions of the four-wave tube are different. ■...Housing, 6...Waveguide, 9...High frequency oscillator, 11...Outlet, 14...Antenna, 15
...Introduction port, 20...Motor drive mechanism, 26...
・Output shaft.

Claims (1)

[Claims] The ceiling of the housing of the microwave oven is provided with a waveguide equipped with a high-frequency oscillator at one end and a high-frequency outlet at the bottom of the other end, and the outlet is located below the waveguide. The antenna is provided with an antenna for distributing radio waves emitted from the housing in a diffusive manner toward the interior of the housing, and the antenna is provided with a high frequency inlet on the upper surface, and the inlet is positioned to overlap with the outlet of the waveguide. The case is further provided with a motor drive mechanism including a motor and an output shaft arranged side by side and a gear train that connects the two, the output shaft protruding from the case and the output shaft A microwave oven that is positioned so as to pass through the outlet and the inlet, and has the antenna coupled to its output shaft in a positional relationship such that the antenna rotates with the outlet and the inlet overlapping each other. In the antenna rotation device, the height of the other end of the waveguide is configured to be an even number of the height of the one end,
The thickness of the case in the above motor drive mechanism is such that the thickness on the motor side is larger than the thickness on the output shaft side in the output shaft direction, and the output shaft side of the case is the other end of the waveguide. The motor side is placed at a position away from the other end of the waveguide, and the upper surface of the case is placed in a position where both the output shaft side and the motor side are located at one end of the waveguide. An antenna rotation device for a microwave oven, characterized in that the antenna is located at the same level or lower than the top surface so as not to protrude from the top surface.