JPH103985A - High frequency heating equipment - Google Patents

Abstract

(57) [Problem] To prevent leakage of high-frequency radio waves without using a choke chamber when a power transmission shaft is penetrated from outside the oven to the inside of the high-frequency heating device. SOLUTION: A tubular inner coil is provided in a through-hole of an oven storage 1 provided with a through-hole 3 having a cylindrical projecting portion 2 for storing an object to be heated and facing the projecting portion 2, A power transmission shaft 5 for transmitting the rotational power generated by the motor to the oven chamber 1 penetrates the inner coil 10, and a capacitor is formed between the protrusion 2, the inner ring 9 and the power transmission shaft 5. In this configuration, high-frequency radio waves leaking out of the oven chamber are attenuated by a low-pass filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating device such as a microwave oven for heating and cooking food with high-frequency energy, and more particularly to a technique for preventing high-frequency energy from leaking from a heating chamber.

[0002]

2. Description of the Related Art Conventionally, a technique for preventing high-frequency energy leakage of a power transmission shaft of a high-frequency heating apparatus of this type has been disclosed in
What was shown in 172828 and Unexamined-Japanese-Patent No. 64-22215 was common. That is, FIG.
As shown in FIG. 7, when the power transmission shaft 21 is penetrated by providing a gap A so as not to hinder the rotation of the power transmission shaft 21 in the oven cabinet 20 that seals high-frequency radio waves for heating food.
A cylindrical choke chamber 22 is provided along the outer periphery of the power transmission shaft 21.
Was installed to seal high-frequency radio waves leaking out of the oven chamber through the shaft. In this case, the dimension A of the choke chamber had to be λ / 4.

[0003]

However, the choke chamber has a complicated structure, and the dimension A of the choke chamber required for high-frequency radio waves of 2.45 GHz used in microwave ovens is about 30 mm. However, there is a problem that the size is increased.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an oven storage in which a through hole having a cylindrical protrusion is provided in an oven storage for storing an object to be heated, A high-frequency supply means for supplying high-frequency power to the object to be heated, and a power transmission shaft for transmitting power to the oven chamber, wherein the power transmission shaft penetrates the through hole and is between the protrusion and the coil portion. relative dielectric constant is provided a spacer k _e, it has a configuration forming a capacitor between the power transmission shaft and the projecting portion.

[0005] In the above invention, the oven chamber 1 provided with a through-hole having a cylindrical protrusion having an inner diameter D and a height h as shown in FIG. outer diameter D · the diameter d · length h · relative dielectric constant equivalent electric circuit between the spacers 15 is a k _e is as shown in FIG.

In FIG. 15, R is the electric resistance of the portion of the power transmission shaft that protrudes into the oven chamber, and C is the capacitance of the capacitor at the protruding portion, which is calculated by equation (1).

[0007]

(Equation 1)

The circuit shown in FIG. 15 is a low-pass filter, and the high-frequency current I excited on the power transmission shaft by the high-frequency wave generated by the high-frequency supply means # 4 is attenuated at the cut-off frequency ω ₀ or more represented by the _{equation (} 2). .

[0009]

(Equation 2)

Therefore, the frequency ω> ω ₀ of the high frequency generating means
By selecting the shapes and materials of the through hole, the power transmission shaft, and the spacer so as to satisfy the above condition, it is possible to reduce the high-frequency current and the high-frequency electric wave leaking out of the oven storage without using a choke chamber.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oven storage provided with a through-hole having a cylindrical projection for storing an object to be heated, and a high-frequency supply for supplying high-frequency power to the object to be heated in the oven storage. Means, and a power transmission shaft for transmitting power into the oven chamber, wherein the power transmission shaft penetrates the through-hole, a capacitor is formed between the through-hole and the power transmission shaft, and a low-pass filter is used. It is configured to attenuate high frequency radio waves leaking out of the oven storage.

The power transmission shaft has a thick portion with a large diameter, and the thick portion is provided at a position opposed to the protrusion of the through hole to form a capacitor formed between the protrusion and the power transmission shaft. And the cut-off frequency is lowered to increase the attenuation of high-frequency radio waves leaking out of the oven storage.

[0013] Further, a cylindrical inner ring is provided at a position opposed to the projecting portion of the through hole in an oven storage provided with a through hole having a cylindrical projecting portion for storing an object to be heated, and a power transmission shaft is provided. With the configuration penetrating through the inner ring, a capacitor is formed between the protruding portion, the inner ring, and the power transmission shaft, and a low-pass filter attenuates high-frequency radio waves leaking out of the oven storage.

Further, a spiral inner coil is provided in an oven storage provided with a through-hole having a cylindrical protruding portion for accommodating an object to be heated, at a position facing the protruding portion of the through-hole, and a power transmission shaft is provided. With the configuration penetrating through the inner coil, a capacitor is formed between the protruding portion, the inner coil, and the power transmission shaft, and the low-pass filter is configured to attenuate high-frequency radio waves leaking out of the oven storage.

[0015] Further, the coil section penetrates a power transmission shaft having a coil section partially spirally formed in an oven storage provided with a through-hole having a cylindrical projecting section for accommodating an object to be heated. It is provided at a position facing the projecting portion of the hole, and a capacitor is formed between the projecting portion, the inner coil, and the power transmission shaft, and a low-pass filter attenuates high-frequency radio waves leaking out of the oven storage. .

A power transmission shaft having a cylindrical shaft ring mounted concentrically with the shaft is provided in an oven storage provided with a through-hole having a cylindrical projecting portion for storing the object to be heated.
A configuration in which the shaft ring is provided at a position facing the protrusion of the through hole, a capacitor is formed between the protrusion, the shaft ring, and the power transmission shaft, and a low-pass filter attenuates high-frequency radio waves leaking out of the oven cabinet. It is what it was.

Further, a power transmission shaft having a helical shaft coil mounted concentrically with the shaft is provided in an oven storage provided with a through-hole having a cylindrical protruding portion for storing an object to be heated. A coil is provided at a position opposed to the projecting portion of the through hole, and a capacitor is formed between the projecting portion, the shaft coil and the power transmission shaft, and a low-pass filter is used to attenuate high-frequency radio waves leaking out of the oven cabinet. Things.

Also, at least a portion between the protrusion and the power transmission shaft, the protrusion and the inner ring, the inner ring and the power transmission shaft, the protrusion and the inner coil, the inner coil and the power transmission shaft, and the protrusion and the coil portion. Providing a spacer having a relative permittivity of 1 or more, forming a capacitor between the through hole and the power transmission shaft, forming a low-pass filter having an increased damping effect by increasing the capacitance by sandwiching the spacer. Then, it is configured to attenuate high frequency radio waves leaking out of the oven storage.

(Embodiment 1) FIG. 1 is a cutaway perspective view of a main part of a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the main part.

1 and 2, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protruding portion 2 for storing an object to be heated, and 4 denotes an oven storage in the oven storage 1. High-frequency power supply means such as a magnetron for supplying a high-frequency electric wave of 2.45 GHz is provided. Reference numeral 5 denotes a power transmission shaft for transmitting the rotational power generated by the motor 6 to a turntable or the like in the oven storage 1. The power transmission shaft 5 penetrates through the through hole 3, a capacitor is formed between the protrusion 2 and the power transmission shaft 5, and a low-pass filter attenuates high-frequency radio waves leaking out of the oven storage. Things.

In FIG. 2, the length h of the protrusion 2 is 20.
mm, through hole diameter D = 10.4mm, power transmission shaft diameter d = 10mm
, The capacitance of the capacitor formed between the protruding portion and the power transmission shaft is 26.5 μF, and in a microwave oven having a shaft impedance of 3Ω,
The cutoff frequency of the more axis is 2 GHz. With this configuration, leakage high-frequency radio waves can be halved compared to a configuration in which the protruding portion 2 is not provided.

Further, in the above configuration, the leakage high-frequency damping effect does not change even if the power transmission shaft moves in the thrust direction to some extent as long as a capacitor is formed between the protrusion and the power transmission shaft. Therefore, for example, the leakage high-frequency damping effect does not change even when the power transmission shaft moves when the weight sensor 7 is attached and the load is measured by bending.

(Embodiment 2) FIG. 3 is a cutaway perspective view of a main part of a second embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of the main part.

In FIGS. 3 and 4, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protruding portion 2 for storing an object to be heated, and 4 denotes an object to be heated in the oven storage 1. A high frequency supply means such as a magnetron for supplying a high frequency radio wave of 2.45 GHz has a thick portion 8 having a large diameter for transmitting the rotating power generated by the motor 6 to a turntable or the like in the oven storage 1. It is a power transmission shaft. The power transmission shaft 5 penetrates through the through hole, and a capacitor is formed between the protruding portion 2 and the thick portion 8,
The low-pass filter attenuates high-frequency radio waves leaking out of the oven cabinet.

In FIG. 4, the length h of the protrusion 2 is 20.
mm, the through-hole diameter D = 20.4 mm, and the thick part diameter d = 20 mm, the capacitance of the capacitor formed between the through-hole and the power transmission shaft is 56.2 μF. Therefore, in a microwave oven having a shaft impedance of 3Ω, the cutoff frequency of the shaft is 0.94 GHz according to Equation 2. According to this configuration, the leaked high-frequency radio wave can be reduced to about 比 べ as compared with the configuration in which the protrusion 2 is not provided.

Further, in the present configuration, the shape of the thick portion is made longer than the amount by which the power transmission shaft moves in the thrust direction, so that the capacitor is connected between the protruding portion and the thick portion as in the first embodiment. As long as the power transmission shaft is slightly moved in the thrust direction, the leakage high-frequency damping effect does not change. Therefore, for example, the leakage high-frequency damping effect does not change even when the power transmission shaft moves when the weight sensor 7 is attached and the load is measured by bending.

(Embodiment 3) FIG. 5 is a cutaway perspective view of a main part of a third embodiment of the present invention, and FIG. 6 is a longitudinal sectional view of the main part.

In FIGS. 5 and 6, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protrusion 2 for storing an object to be heated, and 9 denotes a through-hole 3 of the through-hole 3. Reference numeral 4 denotes a high-frequency supply means such as a magnetron for supplying a high-frequency radio wave of 2.45 GHz to the object to be heated in the oven chamber 1; It is a power transmission shaft for transmitting the generated rotational power to a turntable or the like in the oven storage 1.

The power transmission shaft 5 penetrates through the inner ring 9 to form a capacitor between the protruding portion 2, the inner ring 9 and the power transmission shaft 5, and leaks out of the oven cabinet by a low-pass filter. It is configured to attenuate high frequency radio waves.

In FIG. 6, the length h = 6.
In the case of 5 mm, through hole diameter D = 17 mm, power transmission shaft diameter d = 3 mm, inner ring outer diameter dr = 9.5 mm, and ring thickness 1 mm, as shown in FIG. Can be reduced to a degree.

Further, in this configuration, as long as a capacitor is formed between the protruding portion, the inner ring, and the power transmission shaft, the leakage high-frequency damping effect does not change even if the power transmission shaft slightly moves in the thrust direction. Absent. Therefore, for example, the leakage high-frequency damping effect does not change even when the power transmission shaft moves when the weight sensor 7 is attached and the load is measured by bending.

(Embodiment 4) FIG. 7 is a cutaway perspective view of a main part of a fourth embodiment of the present invention, and FIG. 8 is a longitudinal sectional view of the main part.

In FIGS. 7 and 8, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protruding portion 2 for storing an object to be heated, and 10 denotes the protruding portion 2 of the through-hole 3.
A cylindrical inner coil provided at a position facing the
Reference numeral 5 denotes a high-frequency supply unit such as a magnetron that supplies a high-frequency radio wave of 2.45 GHz to the object to be heated in the oven chamber 1, and 5 transmits the rotational power generated by the motor 6 to a turntable or the like in the oven chamber 1. Power transmission shaft.

The power transmission shaft 5 penetrates through the inner coil 10 and forms a capacitor between the protrusion 2, the inner ring 9 and the power transmission shaft 5, and leaks out of the oven by a low-pass filter. It is configured to attenuate high frequency radio waves.

In FIG. 8, the length h of the protruding portion 2 is 6.
In the case of 5 mm, through hole diameter D = 17 mm, power transmission shaft diameter d = 3 mm, inner coil outer diameter dc = 9.5 mm, and coil wire diameter 0.8 mm, as shown in FIG. It can be reduced to about 40%.

Further, in this configuration, as long as a capacitor is formed between the protruding portion, the inner coil, and the power transmission shaft, the leakage high-frequency damping effect does not change even if the power transmission shaft slightly moves in the thrust direction. Absent. Therefore, for example, the leakage high-frequency damping effect does not change even when the power transmission shaft moves when the weight sensor 7 is attached and the load is measured by bending.

(Embodiment 5) FIG. 9 is a longitudinal sectional view of a main part of Embodiment 5 of the present invention.

In FIG. 9, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protrusion 2 for storing an object to be heated, and 11 denotes a rotating power generated by a motor 6 in the oven storage 1. Is a power transmission shaft having a coiled part 12 that is spirally machined, and the power transmission shaft 5 penetrates through the through-hole, and the coil part 12 is protruded from the protrusion 2. Is provided at a position opposed to. Therefore, the protrusion 2 and the coil 1
2, a capacitor is formed between them and a low-pass filter is used to attenuate high-frequency radio waves leaking out of the oven storage.

In FIG. 9, the length h of the protruding portion 2 is 6.
5mm, through hole diameter D = 17mm, power transmission shaft diameter d = 0.8m
m, the outer diameter of the coil portion is 9.5 mm.

(Embodiment 6) FIG. 10 shows Embodiment 6 of the present invention.
It is a longitudinal cross-sectional view of the principal part of.

In FIG. 10, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical projection 2 for storing an object to be heated, and 5 denotes a rotating power generated by a motor 6 in the oven storage 1. And a cylindrical shaft ring 13 is attached to the power transmission shaft 5 concentrically with the shaft, and the shaft ring 13 faces a protruding portion of the through hole. A capacitor is formed between the protruding portion, the shaft ring 13 and the power transmission shaft, and a low-pass filter is used to attenuate high-frequency radio waves leaking out of the oven chamber. This is realized by a simple configuration.

(Embodiment 7) FIG. 11 shows Embodiment 7 of the present invention.
It is a longitudinal cross-sectional view of the principal part of.

In FIG. 11, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical projecting portion 2 for storing an object to be heated, and 5 denotes a rotating power generated by a motor 6 in the oven storage 1. And a cylindrical shaft coil 14 is attached to the power transmission shaft 5 concentrically with the shaft, and the shaft coil 13 faces a protruding portion of the through hole. A capacitor is formed between the protruding portion, the shaft coil 14 and the power transmission shaft, and a high-frequency electric wave leaking out of the oven chamber is attenuated by a low-pass filter. This is realized by a simple configuration.

(Eighth Embodiment) FIG. 12 is a longitudinal sectional view of a main part of an eighth embodiment of the present invention.

In FIG. 12, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protrusion 2 for storing an object to be heated, and 5 denotes a rotating power generated by a motor 6 in the oven storage 1. Reference numeral 15 denotes a cylindrical spacer having a relative dielectric constant of 1 or more, such as crystallized glass or titanium oxide porcelain.

The power transmission shaft 5 penetrates through the through hole 3, and the spacer 15 is interposed between the protrusion 2 and the power transmission shaft 5 to form a capacitor having a large capacitance. The filter is configured to attenuate high-frequency radio waves leaking out of the oven cabinet by a filter.

In the configuration shown in FIG. 12, when a titanium oxide porcelain having a relative dielectric constant of 100 is used as the spacer, the leaked high frequency radio wave can be reduced to 1/50 as compared with the case where no spacer is provided.

(Embodiment 9) FIG. 13 is a longitudinal sectional view of a main part of Embodiment 9 of the present invention.

In FIG. 13, reference numeral 1 denotes an oven storage provided with a through-hole 3 having a cylindrical protrusion 2 for storing an object to be heated, and 9 denotes a position of the through-hole 3 facing the protrusion 2. Reference numeral 5 denotes a power transmission shaft for transmitting the rotational power generated by the motor 6 to a turntable or the like in the oven chamber 1, and reference numeral 15 denotes crystallized glass, titanium oxide porcelain, or the like. Is a cylindrical spacer having a relative dielectric constant of 1 or more.

The power transmission shaft 5 penetrates the inner ring 9, and the spacers are interposed between the protrusion 2 and the inner ring 9 and between the inner ring 9 and the power transmission shaft 5, respectively. The protrusion 2 and the inner ring 9
A capacitor having a large capacitance is formed between the power transmission shaft 5 and the power transmission shaft 5, and a low-pass filter attenuates high-frequency radio waves leaking out of the oven storage.

In the configuration shown in FIG. 13, when a titanium oxide porcelain having a relative dielectric constant of 100 is used as the spacer, the leaked high-frequency radio wave can be reduced to 1/50 as compared with the case where no spacer is provided.

It should be noted that a similar effect can be obtained when the spacers are provided in the structures of the fourth to seventh embodiments.

[0053]

As described above, the high-frequency heating device of the present invention has the following effects.

(1) The choke chamber is provided by a configuration in which the power transmission shaft penetrates a through hole having a cylindrical protrusion of the oven storage, and a capacitor is formed between the through hole and the power transmission shaft. Without high frequency, high frequency current and high frequency radio wave leaking out of the oven can be reduced with a small configuration.

(2) The power transmission shaft penetrates a through hole having a cylindrical protrusion of the oven storage, and a cylindrical inner ring or an inner coil is provided between the through hole and the power transmission shaft. With a configuration that forms a condenser, even if there is a large difference between the through hole and the outer shape of the power transmission shaft, a small configuration reduces high-frequency currents and high-frequency radio waves leaking out of the oven chamber without providing a choke chamber. Can be done.

(3) The power transmission shaft has a coil part which is partly processed into a spiral shape, and the coil part is provided at a position facing the protrusion of the through-hole. The current and high frequency radio waves can be greatly reduced.

(4) Projecting portion and power transmission shaft, projecting portion and inner ring, inner ring and power transmitting shaft, projecting portion and inner coil, internal coil and power transmitting shaft, at least a portion between projecting portion and coil portion By providing a spacer having a relative dielectric constant of 1 or more, a high-frequency current and a high-frequency radio wave leaking out of the oven chamber can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of a main part of a high-frequency heating device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the high-frequency heating device in the embodiment of FIG.

FIG. 3 is a cutaway perspective view of a main part of a high-frequency heating device according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of the high-frequency heating device in the embodiment of FIG. 3;

FIG. 5 is a cutaway perspective view of a main part of a high-frequency heating device according to a third embodiment of the present invention.

6 is a longitudinal sectional view of a main part of the high-frequency heating device in the embodiment of FIG.

FIG. 7 is a cutaway perspective view of a main part of a high-frequency heating device according to a fourth embodiment of the present invention.

8 is a longitudinal sectional view of a main part of the high-frequency heating device in the embodiment of FIG. 7;

FIG. 9 is a longitudinal sectional view of a main part of a high-frequency heating device according to a fifth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a main part of a high-frequency heating device according to a sixth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of a main part of a high-frequency heating device according to a seventh embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a main part of a high-frequency heating device according to an eighth embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of a main part of a high-frequency heating device according to a ninth embodiment of the present invention.

FIG. 14 is a longitudinal sectional view of a main part of a high-frequency heating device according to an embodiment of the present invention.

15 is an equivalent electric circuit diagram in the embodiment of FIG.

FIG. 16 is a graph showing the relative leakage characteristics of a high-frequency heating device according to an embodiment of the present invention.

FIG. 17 is a longitudinal sectional view of a main part of a conventional heating cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oven storage 2 Projection part 3 Through-hole 4 High frequency supply means 5 Power transmission shaft 8 Thick part 9 Inner ring 10 Inner coil 11 Power transmission shaft 12 Coil part 13 Axis ring 14 Axis coil 15 Spacer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Nitta 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] An oven having a through-hole having a cylindrical projecting portion for storing an object to be heated, a high-frequency supply means for supplying high-frequency power to the object to be heated in the oven, and the oven It consists of a power transmission shaft that transmits power inside,
A high-frequency heating device having a configuration in which the power transmission shaft penetrates the through hole and a capacitor is formed between the through hole and the power transmission shaft. 2. The high-frequency heating device according to claim 1, wherein the power transmission shaft has a thick portion having a large diameter, and the thick portion is provided at a position facing the protrusion of the through hole. . 3. An oven storage provided with a through hole having a cylindrical projection and containing an object to be heated, and a cylindrical inner ring provided at a position facing the projection of the through hole. A high-frequency supply unit that supplies high-frequency power to the object to be heated in the oven chamber, and a power transmission shaft that transmits power into the oven chamber, wherein the power transmission shaft penetrates the inner ring, and A high-frequency heating device configured to form a capacitor between the inner ring and the power transmission shaft. 4. An oven storage for storing an object to be heated and having a through hole having a cylindrical protrusion, a helical inner coil provided at a position of the through hole facing the protrusion. High-frequency supply means for supplying high-frequency electric waves to the object to be heated in the oven, and a power transmission shaft for transmitting power to the oven; the power transmission shaft penetrates the inner coil; A high-frequency heating device having a configuration in which a capacitor is formed between the inner coil and the power transmission shaft. 5. The power transmission shaft according to claim 1, wherein the power transmission shaft has a coil part partially formed in a spiral shape, and the coil part is provided at a position facing the protrusion of the through hole. High frequency heating device. 6. A power transmission shaft, wherein a cylindrical shaft ring is mounted concentrically with the shaft, and the shaft ring is provided at a position facing a projecting portion of the through hole. 2. The high-frequency heating device according to 1. 7. A power transmission shaft, wherein a helical shaft coil is mounted concentrically with the shaft, and the shaft coil is provided at a position opposed to a protrusion of the through hole. The high-frequency heating device as described. 8. A protruding portion and a power transmission shaft, a protruding portion and an inner ring, an inner ring and a power transmission shaft, a protruding portion and an inner coil, an inner coil and a power transmission shaft, and at least a portion between a protruding portion and a coil portion. The high-frequency heating device according to any one of claims 1 to 7, wherein a spacer having a relative dielectric constant of 1 or more is provided.