JPH0151869B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a cooking device such as a microwave oven or an oven range that heats food using microwaves generated by a magnetron. Regarding cooking equipment.

When heating food using microwaves,
If pure standing wave mode microwaves are supplied into the cooking chamber where the food to be cooked is stored, the food will be heated unevenly, so it is recommended that higher mode microwaves be supplied. This prevents uneven heating.

That is, as shown in FIG. 1, which is a schematic cross-sectional view of a conventional general microwave oven, microwaves generated by a magnetron 1 are transmitted through a slit through a waveguide 2 provided on the top surface of a cooking chamber 3. S is supplied to the cooking chamber 3.

The food F is placed on a turntable 4 that is rotationally driven by a motor (not shown) and rotated, and a stirrer 5 provided on the top of the cooking chamber 3 disturbs the microwaves to change the electric field distribution. to ensure that food F is heated evenly.

However, even if the above-mentioned measures are taken, the reality is that it is still not enough to eliminate uneven heating, and in this configuration, the device for rotating the stirrer 5 and turntable 4 is In addition, there were problems such as the need for electric power to drive these devices.

The present invention has been made in view of the above circumstances, and includes a plurality of waveguides that guide microwaves from one magnetron to the cooking chamber, and the wavelength and phase can be adjusted by using a plurality of waveguides that guide microwaves from one magnetron to the cooking chamber. The object of the present invention is to provide a cooking device that can eliminate uneven heating by supplying microwaves of different speeds to a cooking chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 2 is a schematic cross-sectional view of the cooking device according to the present invention, in which microwaves generated by the magnetron 1 are transferred to the food F placed on the turntable 4 through the main waveguide 20, the sub-waveguide 21, Waveguide section 2 consisting of 22
Heating is carried out by supplying electricity to the cooking chamber 3 from a slit-shaped microwave supply port via a stirrer 5 while stirring the cooking chamber 3.

FIG. 3 is a partially cutaway perspective view of the waveguide section 2 of the device of the present invention.

The waveguide section 2 includes a main waveguide 20 and sub-waveguides 21 and 22 provided on the lower surface thereof, that is, on the cooking chamber 3 side.

The main waveguide 20 is provided on the top surface of the cooking chamber 3 and has a substantially rectangular cylindrical shape with a rectangular cross section having a width dimension _a0 , with one end extending to the side of the cooking chamber 3, A magnetron 1 is provided on the lower surface, and its antenna protrudes into the main wave pipe 20 from the bottom plate B of the main wave pipe 20. The top surface of the other end is sloped and connected to the top surface of the cooking chamber 3.

Then, on the bottom plate B of the main waveguide 20, that is, on the top side of the cooking chamber 3, from the antenna side of the magnetron 1, slits S ₁ (length a ₁ ), S ₂ (length a ₀ ), S ₃ (length a ₀ ) and S ₄ (length a ₂ ), and the longitudinal direction of each slit is the width direction of the main waveguide 20, and the length is a ₀ > a ₂ > a ₁ . It's summery.

A stirrer 5 is rotatably provided between the slits S ₂ and S ₃ in the center of the top surface of the cooking chamber 3.

Also, the bottom plate B ₁ between slit S ₁ and slit S ₂
On the lower surface side, that is, on the cooking chamber 3 side, there is a rectangular cross section with a width direction dimension a 1 _, with the slit S ₂ side cross section opened from the edge of the slit S ₁ on the magnetron 1 side to the edge of the slit S 2 on the magnetron ₁ side. The sub-waveguide 21 in the shape of a flat hollow rectangular parallelepiped further has slits S ₃ and S _{4 .}
On the lower surface of the bottom plate B ₃ between the slit S ₃ and the slit S 3, the side cross section is opened from the edge of the slit S ₃ far from the magnetron 1 to the edge of the slit S 4 far from the magnetron ₁ , and the lower surface of the slit S ₄ is opened. A hollow prismatic sub-waveguide 22 is provided which has a sloped width dimension _a2 and is trapezoidal in side view.

The sub waveguide 21 connects to the main waveguide 20 at the slit _S1 .
The sub waveguide 22 communicates with the cooking chamber 3 through the opening on the slit S ₂ side, and the sub waveguide 22 communicates with the main waveguide 20 through the slit S ₄ and with the cooking chamber 3 through the opening on the slit S ₃ side. There is.

Further, the sub-waveguides 21 and 22 have widthwise dimensions a ₁ and a ₂ that are different from the widthwise dimension a ₀ of the main waveguide 20 (a ₀ >a ₂
>a ₁ ), the microwaves supplied to the cooking chamber 3 from the slits S ₂ and S ₃ and the sub-waveguides 21 and 22 have different phases.

FIG. 4 is a schematic explanatory diagram showing the phase of microwaves in the waveguide section 2. FIG. The microwave P ₁ generated by the magnetron 1 passes through the main waveguide 20 and the slit S ₁ to the sub waveguide 21 and becomes the microwave P _{2 .}
Power is supplied to the cooking chamber 3 from the slit S2, and power is also supplied to the cooking chamber ₃ from the slit S2.

In this case, the wavelength λg and phase velocity in the waveguide
There is a relationship between vp and vp as shown in the following formula.

Where, λ: Free space wavelength a: Waveguide width (TE ₁₀ mode) f: Frequency (constant: 2450MHz) The wavelength λg in the waveguide is determined by the waveguide width a, and the phase velocity vp is determined by the frequency f. Since it is constant, it is determined by the wavelength λg. That is, each waveguide width a
If they are different, the wavelength λg and phase velocity vp in each waveguide 20, 21, 22 will be different.

Therefore, the microwave P 1 supplied from the slit S ₂ to the cooking chamber 3 and _{the microwave P 2 from} the sub waveguide 21
are out of phase with each other, and the microwave P ₁ that is similarly supplied from the slit S ₃ to the cooking chamber 3
The phase of the microwave P _{3 is different from that of the microwave P 3} that is fed to the cooking chamber 3 via the sub-waveguide 22 . Furthermore, the phase of the microwaves P ₁ and P ₁ ' differs due to the difference in the distance between the magnetron 1 and the slits S ₂ and S ₃ , and similarly, the phase of the microwave P ₂ differs due to the difference in the distance between the slits S ₁ and S ₃ . Since the phase of P 3 and P ₃ are also different, cooking chamber 3
Four types of microwaves with different phases P ₁ , P ₁ ′, P ₂ ,
P ₃ is supplied and a very complex higher-order mode is generated.

Combined with the microwave disturbance effect by the starrer 5 provided on the lower surface of the bottom plate B ₂ of the main waveguide 20 between the slits S ₂ and S ₃ , extremely complex high-order mode microwaves are generated in the cooking chamber 3. will be supplied with electricity.

Therefore, in the device of this invention, the microwaves generated by the magnetron 1 are transmitted from the slits S ₂ and S ₃ to the cooking chamber 3, and from the slits S ₁ and S ₂ have a width direction dimension different from that of the main waveguide 20. Sub-waveguides 21, 22
When the microwave is supplied to the cooking chamber 3 through the microwave, the phase becomes even more different, and therefore the microwaves supplied to the cooking chamber 3 have a very complex higher-order mode.

As detailed above, the cooking appliance according to the present invention is a cooking appliance in which microwaves generated by one magnetron are supplied to the cooking chamber through a waveguide section, and the waveguide section includes: A main waveguide located on the magnetron antenna side, and a plurality of subguides formed in the main waveguide and connected to the main waveguide via different slits at different distances from the magnetron antenna, each having a different width dimension. The main waveguide has another slit that communicates directly with the cooking chamber, and the tip of the sub-waveguide communicates with the cooking chamber, so complex higher-order modes are generated within the cooking chamber. The present invention has excellent effects such as no uneven heating due to the microwave power being supplied.

In the above embodiment, two sub-waveguides are provided, but it goes without saying that three or more sub-waveguides may be provided.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of a general cooking device having a magnetron, Fig. 2 is a schematic sectional view of the device of the present invention, Fig. 3 is a partially cutaway perspective view of its waveguide section, and Fig. 4 FIG. 2 is an explanatory diagram showing the phase of microwaves within a waveguide. 1... Magnetron, 2... Waveguide section, 3...
Heating cooking chamber, 20... Main wave pipe, 21, 22...
Sub-waveguide.

Claims (1)

[Claims] 1. In a cooking device configured to feed microwaves generated by one magnetron to a cooking chamber via a waveguide section, the waveguide section includes a main waveguide located on the magnetron antenna side; The main waveguide includes a plurality of sub-waveguides formed in the main waveguide and connected to the main waveguide through separate slits having different distances from the magnetron antenna, each having a different width dimension. A cooking appliance characterized in that it has another slit that communicates directly with the chamber, and the tip of the sub waveguide communicates with the cooking chamber.