JPH03283290A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To enhance the capacity efficiency of a heating cooking room so as to satisfy the requirement for miniaturizing the main body of a high frequency heating device and reduce the cost and weight of the device by inclining the mating face of the main body with a door. CONSTITUTION:The mating face 21 of a main body 11 and a door 18 is inclined. Therefore the wall thickness A of the main body 1 can be increased more than the width size L of the mating face 21. Even when the wall thickness A of the main body 11 is smaller than usual, the distance required for preventing leakage of high frequency can be secured as the width size L of the mating face 21 of the door 18. Thereby the wall thickness A of the main body 11 can be decreased and the capacity efficiency of a beating cooking room 12 is enhanced and the requirement for miniaturizing the the main body 11 is satisfied, thereby achieving cost and weight reductions of the high frequency heating device.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides high frequency (microwave)
A high-frequency heating device that heats by irradiating it.

(Prior Art) The general structure of a conventional high-frequency heating device will be explained based on FIGS. 7 and 8. FIG. 7 is a plan view of the entire main body 1 (
However, the top plate is broken). As shown in FIG. 7, inside the main body 1, a heating cooking chamber 2 and a machine room 3 are provided side by side, and a magnetron 4 is provided in the machine room 3 as a high frequency generating means. This magnetron 4 generates a high frequency wave of 2450 MHz, and this high frequency wave is guided into the heating cooking chamber 2 through a waveguide 5. If a large amount of this high frequency leaks to the outside, it will have an adverse effect on the human body, so it is necessary to prevent the high frequency from leaking from the gap between the door 6 that opens and closes the heating cooking chamber 2 and the main body 1. Therefore, conventionally, a choke cavity 7 for high frequency attenuation is formed on the four sides of the door 6 as shown in FIG. 8, and the center of the opening 7a of the choke cavity 7 and the opening end of the cooking chamber 2 The distance is set to λ/4 (λ is the wavelength of the high frequency). Furthermore, considering that choke cavity 7 cannot completely prevent radio wave leakage,
Attenuation range fI (N-1 to 1.5cm at 2450MHz
) has been established. Due to the above dimensional relationship, the main body 1
It was necessary to set the wall thickness to L-λ/4+g (1).

(Problem to be Solved by the Invention) By the way, since the frequency of a conventional high frequency is 2450 MHz, one wavelength λ is approximately 12.2 cm. Further, since the attenuation range g is normally required to be 1 to 1.5 an, the wall thickness of the main body 1 is required to be approximately 4 cm or more if calculated according to the above equation (1). Since such a thick wall must be provided all around the heating cooking chamber 2, the volumetric efficiency, which is the ratio of the internal volume of the heating cooking chamber 2 to the external volume of the main body 1, becomes low, and is 40% at most.
The limit was to limit it to a certain extent. For this reason, heating cooking chamber 2
If an attempt is made to ensure a sufficient internal volume, the entire main body 1 will become considerably large, which not only goes against the request for miniaturization, but also increases the amount of components that make up the main body 1, resulting in high costs. This resulted in an increase in the weight of the main unit.

The present invention has been made in consideration of these circumstances, and its purpose is to improve the volumetric efficiency of the heating cooking chamber, to meet the demand for downsizing, and to achieve cost reduction and weight reduction. The purpose of this invention is to provide a high-frequency heating device that can.

[Structure of the Invention] (Means for Solving the Problems) The high-frequency heating device of the present invention includes a main body having a heating cooking chamber, and a high-frequency generating means for heating food stored in the heating cooking chamber by irradiating high frequency waves to the food. and a door provided on the main body to open and close the front opening of the heating cooking chamber, wherein the mating surface of the main body and the layer is configured to be inclined.

In this case, the front surface of the main body and the front surface of the door may be substantially on the same plane.

Furthermore, the high frequency generating means may be configured to generate a high frequency of approximately 5800 MHz.

(Function) Since the mating surface between the main body and the door is configured to be inclined, the width dimension of the mating surface of the door can be made larger than the wall thickness of the main body. Therefore, even if the wall thickness of the main body is thinner than before, the width of the mating surface of the door can ensure a sufficient distance to prevent high frequency leakage. For this reason,
It is possible to reduce the wall thickness of the main body.

Furthermore, by configuring the front of the main unit and the front of the door to be almost on the same plane, the front of the high-frequency heating device can be made flat, making it more compact and improving the novelty of the external design. can.

Moreover, if the frequency of the high frequency is set to 5800 MHz, the wavelength λ of the high frequency will be less than half of the conventional (2450 MHz). Therefore, the high frequency leakage prevention distance (width dimension L of the mating surface between the main body and the door) calculated by λ/4 + g is also
The wall thickness of the main body can be reduced to about half that of the conventional one, making it possible to further reduce the wall thickness of the main body.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 6.

The main body 11 of the high-frequency heating device has a rectangular box shape, and inside thereof a cooking chamber 12 and a machine chamber 13 are arranged side by side. A waveguide 14 is attached to the upper surface of the heating cooking chamber 12 so as to protrude into the machine room 13 as shown in FIG. A barrel magnetron 15 is attached. This magnetron 15 has a conventional frequency (2450 MHz
), approximately 5800 MHz, which is approximately twice the frequency of
It is configured to generate high frequency waves. Here, 5
The reason for limiting the frequency to 800 MHz is as follows.

In other words, the frequencies permitted to be used for high frequency heating etc. according to the Radio Law are 2450 MHz and 5800 MHz.
There are three types: , 22125MHz.

In general, the smaller the wavelength λ, the shallower the energy with which a radio wave penetrates into a substance, and the depth at which the radio wave penetrates becomes shallower, and in order to obtain a uniform depth, it is said that approximately 500 MHz to 5000 MHz is appropriate. Therefore, when a too high frequency is used, the wavelength λ is very small, which tends to be a major factor in causing uneven heating. Therefore, when the highest frequency of 22125 MHz among the above three types of frequencies is adopted, only a certain depth from the surface of the food is heated, and the inside cannot be sufficiently heated.

However, when a frequency of 5800 MHz is adopted, it is possible to obtain a uniform depth similar to the conventional frequency (2450 MHz), and since the frequency is higher than the conventional frequency, the standing wave ( The distribution state of the electric field (electric field) also becomes finer, and uneven heating is further reduced, resulting in uniform heating. Therefore, by adopting 5800MHz, as shown in Figure 6, the wavelength λ in the conventional case of 2450MHz is 1.
2.2(1), whereas at 5800 MHz, which is the frequency of this example, the wavelength λ is 5.17cI11
This is less than half of the conventional value.

On the other hand, as shown in FIG. 4, a food placement tray 16 is rotatably provided at the bottom of the cooking chamber 12, and the food placement tray 16 is connected to a motor provided at the outer bottom of the cooking chamber 12. 1
Rotationally driven by 7.

As shown in FIG. 3, on the front of the main body 1, there is a door 18 for opening and closing the front of the heating cooking chamber 12, and an operation panel 19.
are arranged on the left and right sides, and the operation panel 19 is provided with various operation keys 20.

The major feature of this embodiment is that, as shown in FIGS. 1 and 2, the mating surface 21 between the main body 11 and the door 18 is formed in an inclined shape. Specifically, each end face of the four sides of the door 18 is inclined toward the center of the cooking chamber 12 by, for example, about 45 inches, and correspondingly, the mating surface 21 of the main body 11 is also inclined by about 45 inches, for example. It is tilted. A choke cavity 22 is formed on the four sides of the door 18 by utilizing the thickness of the door 18. In this case, the size of the choke cavity 22 is determined by the size of the mating surface 21 of the door 18.
The distance from the inner end of the choke cavity 22 to the center of the opening 22a of the choke cavity 22 is λ/4 (about 1.3 cIl+), and the depth dimension of the choke cavity 22 from the center of the opening 22a is also λ/4 (about 1 .3cm). Then, in consideration of the case where the choke cavity 22 cannot completely prevent radio wave leakage, an attenuation region g is provided.
At 800MHz, the wavelength λ is approximately half that of the conventional one, so
This attenuation range g should also be 0.5 to 0.7 an, which is about half of the conventional one (1 to 1.5 cm). Therefore, the main body 11 and the door 18
The width dimension of the mating surface 21 is about 2 cm if calculated according to λ/4+g.

Furthermore, in this embodiment, as shown in FIG.
The front surface 11a of the door 18 and the front surface 18a of the door 18 are set to be substantially on the same plane.

According to the above embodiments, the mating surface 2 between the main body 11 and the door 18
1 is configured in an inclined shape, the wall thickness A of the main body 1 (second
(see figure), the width of the mating surface 21 can be made larger. Therefore, even if the wall thickness A of the main body 11 is thinner than before, the width of the mating surface 21 of the door 18 can ensure a distance necessary to prevent high frequency leakage. Therefore, the wall thickness A of the main body 11 can be made thinner, the volumetric efficiency of the cooking chamber 12 can be improved, and the demand for downsizing the main body 11 can be met, resulting in cost reduction and weight reduction. can.

Furthermore, in this example, the frequency of the high frequency was set to 5800 MHz, which is approximately twice that of the conventional one, so the wavelength of the high frequency was λ.
is 5.17cm, which is about half of the conventional size.

Along with this, the distance required to prevent high frequency leakage (door 18
The width dimension L) of the mating surface 21 may also be about 2 cm, which is half of the conventional width of about 4 cm. For this reason, together with the fact that the mating surface 21 of the door 18 is inclined, the main body 1
It is possible to significantly reduce the wall thickness A of heating cooking chamber 1.
The volumetric efficiency of No. 2 can be increased from about 40% in the conventional case to over 60%.

Moreover, with frequency doubling, the distribution of standing waves (electric fields) in the cooking chamber 12 becomes more finely distributed than in the case of conventional frequencies, as shown in FIG.

Therefore, the food is finely irradiated with high frequency waves, so that the food is heated uniformly, and uneven heating of the food can be improved. This effect is particularly advantageous when heating thin foods (e.g. pizza), as it not only improves the quality of the cooked food but also shortens the heating time, speeding up the cooking process. It is possible to reduce power consumption. In addition, when defrosting frozen foods, conventionally the distribution of standing waves (electric fields) was rough, which resulted in uneven heating and the formation of overheated areas and unthawed areas, making it difficult to thaw properly. Although it had the disadvantage of being difficult,
In the embodiment described above, since the standing wave (electric field) has a finely distributed state, the object to be thawed can be uniformly heated, and there is an advantage that the entire object to be thawed can be thawed evenly and skillfully.

Furthermore, since the front surface 11a of the main body 11 and the front surface 18a of the door 18 are configured to be almost on the same plane, the front surface of the high-frequency heating device can be flattened (flattened), making it more compact and improving the external design. The novelty of the product can be improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways, such as being applicable to a high-frequency heating device with an oven function or a grill function added.

[Effects of the Invention] As is clear from the above description, the present invention is configured such that the mating surface between the main body and the door is inclined, so that the width dimension of the mating surface of the door is smaller than the wall thickness of the main body. can be made larger, the wall thickness of the main body can be made thinner, the volumetric efficiency of the heating cooking chamber can be improved, and the demand for smaller main bodies can be met, reducing costs and weight. can be achieved.

Furthermore, by configuring the front of the main unit and the front of the door to be almost on the same plane, the front of the high-frequency heating device can be made flat, making it more compact and improving the novelty of the external design. can.

In addition, if the high frequency frequency is set to 5800 MHz, the wavelength of the high frequency will be less than half of the conventional (2450 MHz), so the high frequency leakage prevention distance (width dimension of the mating surface of the door) will also be about half compared to the conventional. This allows the wall thickness of the main body to be made even thinner and the layers to be more compact. Moreover, with frequency doubling, the distribution of standing waves (electric fields) in the cooking chamber becomes finer, so when heating thin foods (e.g. pizza), uniform heating improves the quality of the cooking. At the same time, heating time can be shortened, speeding up cooking and reducing power consumption. Furthermore, when thawing frozen foods, there is an advantage that the object to be thawed can be uniformly heated and the entire object to be thawed can be thawed evenly and skillfully.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention,
Fig. 1 is a plan view of the main body with the top plate cut away, Fig. 2 is a cross-sectional view of the mating surface between the main body and the door, Fig. 3 is a front view of the whole, and Fig. 4 is a longitudinal sectional front view of the same. , Fig. 5 is a longitudinal sectional front view of the heating cooking chamber for explaining the distribution state of standing waves, and Fig. 6 shows the wavelength of the high frequency (5800 MHz) of this embodiment and the wavelength of the conventional high frequency (2450 MHz). It is a figure shown by comparison. 7 and 8 show conventional examples, with FIG. 7 being a diagram corresponding to FIG. 1, and FIG. 8 being a diagram corresponding to FIG. 2. In the drawing, 11 is the main body, 12 is a heating cooking chamber, 13 is a machine room, 15 is a magnetron (high frequency generating means), 18 is a door, 2 is a mating surface, and 2 is a choke cavity.

Claims (1)

[Scope of Claims] 1. A main body having a heating cooking chamber, a high frequency generating means for heating food stored in the heating cooking chamber by irradiating high frequency waves, and a front opening of the heating cooking chamber in the main body. What is claimed is: 1. A high-frequency heating device comprising a door provided in such a manner that the main body and the door are connected to each other so that a mating surface between the main body and the door is inclined. 2. The high-frequency heating device according to claim 1, wherein the front surface of the main body and the front surface of the door are substantially flush with each other. 3. The high frequency heating device according to claim 1 or 2, wherein the high frequency generating means generates a high frequency of approximately 5800 MHz.