JP2000164343A - High-frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency heating device having little heating irregularity, capable of shortening the cooking time, and capable of saving energy. SOLUTION: This high-frequency heating device is provided with a heating chamber 2, a lower feeder port 8 and an upper feeder port 9 formed on the wall section of the heating chamber 2 to feed microwaves into the heating chamber 2, and a rotary plate 6 arranged on the bottom section of the heating chamber 2 for mounting an object. The rotary plate 6 is provided with multiple parallel grids (vertical bars and horizontal bars), the interval between the center lines of the grids is set to a 1/4-wavelength, and the length of the grids is set to a 1/2-wavelength or above.

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 for heating food or the like by microwaves.

[0002]

2. Description of the Related Art FIG. 6 is a view showing the configuration of a main part of a conventional high-frequency heating device, and FIG. 7 is a plan view of a rotary plate thereof. In the figure, reference numeral 2 denotes a heating chamber formed in a main body (not shown) forming an outer shell of the high-frequency heating device and having an opening on one side, and the opening is opened and closed by a door (not shown). An operation unit (not shown) having various keys such as a cooking menu key, a cooking key, and a cancel key is provided near the door. 5 is a motor provided at the lower part of the heating chamber 2,
The rotating shaft 5a protrudes from substantially the center of the bottom surface of the heating chamber 2. Reference numeral 6 denotes a rotating plate for mounting an object to be heated, which is fitted into the rotating shaft 5a of the motor 5, and is rotated by driving the motor 5.
Numeral denotes a cooking dish placed on the rotating plate 6, on which an object to be heated is placed and made of heat-resistant glass which transmits microwaves.
Reference numeral 8 denotes a lower power supply port provided on the wall of the heating chamber 2 for supplying microwaves to the inside of the heating chamber 2, and has a lower end located above the rotary plate 6. Reference numeral 9 denotes an upper feed port provided above the lower feed port 8, 10 denotes a magnetron for generating microwaves, 10a denotes an antenna for microwave oscillation, 11 denotes a communication between the lower feed port 8 and the upper feed port 9, and an antenna 10a This is a waveguide for guiding microwaves from the lower feed port 8 and the upper feed port 9 respectively. Reference numeral 12 denotes an object to be heated such as food.

Here, the structure of the rotating plate 6 will be described. The rotating plate 6 has a pair of arc portions 6b formed concentrically from a center portion 6a having a fitting portion fitted with the rotating shaft 5a of the motor 5, and a pair of linear portions formed on diagonal sides of the arc portion 6b. 6c form a substantially elliptical outer shape, and an opening 6j is formed by extending a crosspiece 6i disposed at an equal angle (120 degrees) from the center 6a in the outer shape direction. The rotating plate 6 is formed by punching a metal material, for example, a steel plate by a press to form an opening 6j, and the surface thereof is subjected to chrome plating.

Next, the operation will be described. The cooking dish 7 on which the object to be heated 12 is placed is placed on the rotating plate 6 in the heating chamber 2. Next, by operating the cooking menu key and the cooking key of the operation unit to start the high frequency heating device, the magnetron 1 is started.
0 drives to generate microwaves from the antenna 10a, pass through the waveguide 11, and irradiate the microwaves into the heating chamber 2 from the lower power supply port 8 and the upper power supply port 9. The microwaves radiated from the lower power supply port 8 and the upper power supply port 9 are reflected (incident angle = reflection angle) on the wall of the heating chamber 2 and diffused into the heating chamber 2. At the same time as the magnetron 10 is started, the motor 5 is driven to rotate the rotating plate 6 to stir the microwaves in the heating chamber 2 to make the microwaves in the heating chamber 2 uniform. Since the opening 6j of the rotating plate 6 is formed with an inner peripheral length larger than the wavelength λ (122 mm) of the microwave, the microwave is easily transmitted therethrough.
Penetrates to the bottom of

[0005]

However, since the conventional high-frequency heating device is configured as described above, when a solid food such as meat is put on the cooking dish 7 and cooked,
The temperature of the outside of the meat rises quickly, but the energy of the microwaves is attenuated by being reflected by the wall, so that the microwaves reaching the center are weak and the temperature does not easily rise. Therefore, the temperature difference between the central portion and the outside increases to about 10 degrees. Also, when milk is cooked in a cup, microwaves act strongly on the liquid surface at the top of the cup and the temperature rises, causing convection near the liquid surface, but at the bottom of the cup the microwaves are weak and the temperature rises As a result, the temperature near the liquid surface becomes higher than that at the bottom, so that no convection occurs in the entire cup and a temperature difference of about 5 degrees occurs between the liquid surface and the bottom. In other words, in the conventional apparatus, the heating unevenness of the object to be heated is large, and the heating time is lengthened in order to keep a low temperature at a predetermined temperature. As a result, there is a problem that power consumption increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-frequency heating apparatus which has less heating unevenness, can shorten cooking time, and can save energy.

[0007]

According to the present invention, there is provided a high-frequency heating apparatus comprising: a heating chamber; a power supply port formed on a wall of the heating chamber to supply microwaves into the heating chamber; A rotating plate for mounting an object to be heated, wherein the rotating plate has a plurality of parallel gratings, and a center line interval between the gratings is set to a quarter wavelength, and the length thereof is Is set to a half wavelength or more.

Further, at least a part of the power supply port is opened above the rotary plate.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG.
Is a perspective view of the high-frequency heating device according to the first embodiment, FIG. 2 is a cross-sectional view, and FIG. 3 is a top view showing a rotating plate of the high-frequency heating device. In the drawing, reference numeral 1 denotes a main body forming an outer shell of a high-frequency heating device, 2 denotes a heating chamber formed in the main body 1 and has an opening on one side, 3 denotes a door for opening and closing the opening of the heating chamber 2, and 4 denotes a door 3. An operation unit 5 provided with various keys such as a cooking menu key, a cooking key, and a cancel key is provided at a lower portion of the heating chamber 2, and a rotary shaft 5a is provided at a substantially central portion of the bottom of the heating chamber 2. Is projected. Reference numeral 6 denotes a rotating plate for mounting the object to be heated, which is fitted to the rotating shaft 5a of the motor 5 and rotates by driving the motor 5. Reference numeral 7 denotes a cooking plate to be mounted on the rotating plate 6. And made of heat-resistant glass that transmits microwaves. Reference numeral 8 denotes a lower power supply port provided on the wall of the heating chamber 2 for supplying microwaves to the inside of the heating chamber 2. A part of the lower power supply port 8 is opened above the rotary plate 6, and the lower end thereof is a rotary plate. 6 and below. 9 is an upper power supply port provided above the lower power supply port 8,
Reference numeral 10 denotes a magnetron that generates microwaves, 10a denotes an antenna for microwave oscillation, and 11 denotes a waveguide that communicates with the lower power supply port 8 and the upper power supply port 9 and guides microwaves from the antenna 10a. Reference numeral 12 denotes an object to be heated such as food.

In the first embodiment, the lower end of the lower power supply port 8 is disposed below the rotary plate 6. However, the present invention is not limited to this, and at least a part of the power supply port is opened above the rotary plate 6. Just do it. Further, the power supply port may be one.

Here, the configuration of the rotating plate 6 will be described. The rotating plate 6 has a pair of arc portions 6b formed concentrically from a center portion 6a having a fitting portion fitted with the rotating shaft 5a of the motor 5, and a pair of straight lines formed on diagonal sides of the arc portion 6b. A vertical bar 6d having a substantially elliptical outer shape with the portion 6c and extending from the central portion 6a toward the linear portion 6c.
And four vertical bars 6e arranged at equal intervals b toward the arc portion 6b in parallel with the vertical bar 6d, and an arc portion 6b from the center portion 6a.
6b, and four horizontal rails 6 arranged at regular intervals b toward the linear portion 6c in parallel with the horizontal rail 6f.
g, the entire rotating plate 6 is formed by a plurality of parallel gratings. The rotating plate 6 has a lattice shape formed by punching a metal material, for example, a steel plate with a press, and the surface thereof is subjected to chrome plating.

Here, the distance between the center lines of the crosspieces will be described in detail. The microwave is a sine wave, the wavelength λ of which is about 122 mm, and a half wavelength (1/2
λ) (approximately 61 mm) is the strong electric field portion where the electric field is strongest. In order to integrate microwaves having this characteristic, it is necessary to provide a plurality of antennas having a length of 1 / 2λ or more. Therefore, in the first embodiment, the crosspiece serving as the antenna is arranged as follows. That is, the vertical bars 6d and 6e arranged in parallel to the direction of the circular arc 6b of the outer shape have a center line interval of each vertical bar of 波長 wavelength (1 / 4λ), and between α and γ shown in FIG. Arrangement is made such that the distance between γ and ε and the distance between β and σ are each 1 / 2λ, and the length a of each crosspiece is set to 1 / 2λ or more. Also, the horizontal rails 6f and 6g, which are perpendicular to the vertical rails 6d and 6e, have a center line spacing of 1 / 4λ between the horizontal rails. / 2λ
The length a of each bar is set to 1 / 2λ or more. The opening A formed by the vertical and horizontal rails is formed such that its inner peripheral length is smaller than the wavelength λ of the microwave (about 122 mm).

Next, the operation will be described. The door 3 is opened, the fitting portion of the rotating plate 6 is fitted to the rotating shaft 5 a of the motor 5, the cooking dish 7 on which the object to be heated 12 is placed is placed thereon, and the door 3 is closed. When a cooking menu or a cooking key of the operation unit 4 is pressed, the magnetron 10 is driven to generate microwaves from the antenna 10a, pass through the waveguide 11, and heat from the lower power supply port 8 and the upper power supply port 9. The microwave is irradiated into the storage 2. The microwaves radiated into the heating chamber 2 are reflected and diffused on the wall of the heating chamber 2, but when the microwaves are orthogonal to the vertical beam serving as an antenna, for example, α is weak, β is strong, and γ Is weak and σ is strong, and as shown by the broken line in FIG.
And σ. In addition, α is strong, β is weak, γ is strong and σ is weak, and ε is strong. That is, the microwaves are accumulated on the five vertical rails. In addition, when the microwaves are orthogonal to the horizontal rails, the same operation is performed, and the microwaves are accumulated on five horizontal rails. As a result, the microwaves are concentrated on the object to be heated 12 placed on the cooking dish 7 on the rotating plate 6 to promote heating.

Further, by making the inner peripheral length of the opening A smaller than the wavelength λ of the microwave (about 122 mm), it is difficult to transmit the microwave. More microwaves are intensively irradiated to the upper heated object 12.

When the rotating plate 6 is rotated by the motor 5, the microwaves emitted from the power supply ports each time the vertical rail or the horizontal rail is orthogonal to the lower power supply port 8 or the upper power supply port 9 are transmitted by the antenna. Since the heat is accumulated on a certain vertical or horizontal rail, the microwave is concentrated on the object to be heated 12 placed on the cooking dish 7 on the rotating plate 6 to promote heating. In addition, since the microwaves are agitated by the rotation, the chances of being orthogonal to the vertical beam and the horizontal beam serving as antennas are increased, and the microwaves are more concentrated on the object 12 to be heated. As a result, when the meat is heated, the temperature difference between the center and the outside is about 10 degrees in the past, but about 5 degrees, and the temperature difference between the upper and lower sides is about 5 degrees in the heating of milk. It was three times. In addition, the heating time required to heat 15 g of rice was 1 minute and 40 seconds in the past, but 1 minute, and 1 minute 5 minutes in 150 cc of milk.
What was 0 seconds became 1 minute and 20 seconds.

According to the first embodiment, since the interval between the center lines between the lattices is set to a quarter wavelength and the length of the crosspiece is set to be equal to or more than half the wavelength, the crosspiece is less than microwave. Microwaves have an antenna effect and accumulate on the beam. This allows
The uneven heating of the object to be heated is greatly reduced, and the heating time is also significantly reduced, resulting in an effect of saving energy.

Further, since a part of the power supply port is arranged above the rotating plate, the antenna effect of the beam is improved, and
There is an effect that the object to be heated is easily irradiated with the microwave.

Embodiment 2 FIG. 4 is a top view showing a rotating plate of a high-frequency heating device according to Embodiment 2 of the present invention. In the figure, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description will be omitted. In the figure, 6h is a quarter
The vertical rails are arranged at equal intervals of the wavelength (1 / 4λ), and the vertical rails are arranged by being shifted by 1 / 2b (1 / 8λ) every other row.
In this configuration, the horizontal rails 6f and 6g act as antennas and accumulate microwaves. Since the rotating plate 6 is rotating, when the horizontal rails 6f and 6g are orthogonal to the direction of the power supply port, or when the microwave is orthogonal to the horizontal rails 6f and 6g, the horizontal rails 6f and 6g are the antennas. As a result, the microwaves are integrated, and the object to be heated is intensively heated, so that the heating efficiency is improved.

Embodiment 3 FIG. 5 is a top view showing a rotating plate of a high-frequency heating apparatus according to Embodiment 3 of the present invention. In the figure, the same portions as those in the first or second embodiment are denoted by the same reference numerals, and the description will be omitted. Embodiments 1 and 2
Then, a metal plate is punched with a press and the vertical bars 6d, 6
e, the horizontal rails 6f and 6g are formed in a lattice shape, but the rotating plate 6 of the third embodiment is formed by welding a metal wire by spot welding or the like. Even in this configuration, the first embodiment
It has the same effect as.

In the above-described embodiment, the outer shape of the rotary plate is substantially elliptical. However, the present invention is not limited to this, and it may be circular or rectangular.

[0021]

According to the present invention, a plurality of parallel gratings are provided, the interval between the center lines of the gratings is set to 波長 wavelength, and the length is set to 波長 wavelength or more. Therefore, the grid acts as an antenna to collect microwaves, so that uneven heating of the object to be heated is greatly reduced, and the heating time is also significantly reduced, resulting in an effect of saving energy.

Further, since a part of the power supply port is opened above the rotating plate, the antenna effect of the parallel lattice can be reliably obtained, and the microwave can be easily irradiated on the object to be heated. is there.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of the high-frequency heating device according to the first embodiment of the present invention.

FIG. 3 is a top view showing a rotating plate of the high-frequency heating device according to the first embodiment of the present invention.

FIG. 4 is a top view showing a rotating plate of the high-frequency heating device according to the second embodiment of the present invention.

FIG. 5 is a top view showing a rotating plate of a high-frequency heating device according to Embodiment 3 of the present invention.

FIG. 6 is a main part configuration diagram showing a conventional high-frequency heating device.

FIG. 7 is a plan view showing a rotating plate of a conventional high-frequency heating device.

[Explanation of symbols]

1 body, 2 heating cabinets, 3 doors, 4 operating parts, 5 motors, 6 rotating plates, 6a central part, 6b arc parts, 6c linear parts, 6d, 6e, 6h vertical beams, 6f, 6
g Horizontal beam, 6i beam, 6j opening, 7 cooking dish, 8
Lower feed port, 9 Upper feed port, 10 magnetron, 1
0a antenna, 11 waveguide 7 12 object to be heated.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ichiro Masuda 1728-1 Koeda, Oaza-gun, Hanazono-cho, Osato-gun, Saitama Mitsubishi Electric Home Equipment Co., Ltd. (72) Inventor Masafumi Nagata 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Takayuki Hiramitsu 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 3K090 AA01 AA02 AB02 DA03 EA01 EA02 EA10 3L086 AA04 BB04 BB05 BB07 BB13 DA06 DA07

Claims (2)

[Claims] 1. A heating chamber, a power supply port formed in a wall of the heating chamber to supply microwaves to the inside of the heating chamber, and a rotating plate for mounting a heated object provided at a bottom of the heating chamber. Wherein the rotating plate has a plurality of parallel gratings, the interval between the center lines between the gratings is set to 波長 wavelength, and the length is set to 波長 wavelength or more. High frequency heating device. 2. The high-frequency heating apparatus according to claim 1, wherein at least a part of the power supply port is opened above the rotary plate.