JP2012021738A - High frequency wave heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that in conventional configurations, even in a state where a door is closed completely, a large gap is caused between the opposite surfaces of a heating chamber inner wall and the door, leakage radio wave and hot air leakage in the heating chamber are increased from the gap, but generally, since the leakage radio wave and hot air leakage are increased according to increment of the gap, the gap caused between the opposite surfaces of the heating chamber inner wall and the door are required to be reduced as much as possible.SOLUTION: A high frequency wave heating device is configured so that the opposite surfaces of the electromagnetic wave shielding part 4 of the heating chamber inner wall 3 and door 2 are slanted off a front surface of the door 2, and also is configured so that the heating chamber inner wall 3 and the door 2 do not come into contact with each other when closing and opening the door. Thereby, the gap caused at the opposite surfaces of the electromagnetic wave shielding part 4 of the heating chamber inner wall 3 and door 2 is made smaller than that of the conventional configurations.

Description

  The present invention relates to a high-frequency heating device such as a microwave oven, and more particularly to a high-frequency heating device characterized by the structure of a door.

  As shown in FIG. 10, the conventional microwave oven supplies a heating chamber 1 in which food can be taken in and out by opening and closing the door 2, and an electromagnetic wave (a microwave with a frequency of 2450 MHz; wavelength λ is about 120 mm). And a power supply for heating food, and an electromagnetic wave supply means comprising a magnetron and a waveguide.

  In addition, during high-frequency cooking, if a high frequency leaks to the outside, the human body will be adversely affected. Therefore, it is particularly important to take measures against a high frequency that is about to leak from the gap between the door 2 and the high-frequency heating device body. Therefore, the door 2 has an electromagnetic wave shielding part 4.

  The principle of the choke structure of the electromagnetic wave shielding unit 4 is that a high frequency which is about to leak from a gap between the door 2 and the high frequency heating device main body (a gap formed on the facing surface between the heating chamber wall 3 and the electromagnetic wave shielding unit 4 of the door 2). Is introduced into the choke-structured bag path, reflected at the end of the bag path, and the reflected wave and the high-frequency wave guided into the bag path are combined to maximize the high-frequency voltage and minimize the current at the choke structure entrance 9. It is what you use.

  However, the conventional microwave oven has a configuration in which the door 2 can be easily opened so that the user can easily take in and out food, and a part of the door 2 is inside the heating chamber 1 in the door thickness direction. Since the door 2 does not come into contact with the heating chamber wall 3 when the door 2 is opened and closed, the electromagnetic wave shielding portion 4 between the heating chamber wall 3 and the door 2 even when the door 2 is completely closed. There is a large gap between the facing surfaces.

  For this reason, leakage of hot air when using leaked radio waves, oven function and convection function is large.

JP 2004-63306 A

  The microwave oven is configured so that the user can easily open the door 2 so that the user can easily take in and out the food. Furthermore, since a part of the door 2 enters the heating chamber 1 side, the door 2 does not come into contact with the heating chamber wall 3 when the door 2 is opened and closed. For this reason, even when the door 2 is completely closed, a slight gap is generated between the opposed surfaces of the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2, and the electromagnetic waves in the heating chamber 1 are not affected by the gap. There is a possibility of further propagation to the outside.

  Moreover, there is a possibility that the leakage of hot air may increase from a slight gap generated between the facing surfaces of the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2 when the oven function and the convection function are used. Generally, as the gap becomes larger, leaked radio waves and hot air leaks increase. Therefore, it is necessary to make the gap generated on the facing surface between the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2 as small as possible.

  In order to solve the above-mentioned conventional problems, in the door 2 of the high-frequency heating device having the electromagnetic wave shielding part 4 of the present invention, the heating chamber wall 3 and the electromagnetic wave shielding part 4 of the door 2 are opposed to the front surface of the door 2. The surface is configured to be inclined so that the heating chamber wall 3 and the door 2 do not come into contact with each other when the door is opened and closed. By this structure, the clearance gap produced in the opposing surface of the heating chamber inner wall 3 and the electromagnetic wave shielding part 4 of the door 2 is made smaller than the conventional structure.

  The gap generated on the facing surface between the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2 is made smaller than that of the conventional configuration, thereby preventing leakage radio waves and hot air leakage from the inside of the heating chamber 1 and radio wave shielding performance. And it becomes possible to keep heat insulation performance high.

  Further, in the conventional structure, when designing the door, it is necessary to secure a dimension necessary for configuring the electromagnetic wave shielding part 4 in the door thickness direction. Therefore, the door thickness must be equal to or larger than the electromagnetic wave shielding part 4. However, the thickness reduction in the thickness direction of the door was limited. However, by configuring the facing surface of the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2 to be inclined with respect to the front surface of the door 2, the thickness in the door thickness direction can be reduced as compared with the conventional configuration. It becomes possible.

Sectional drawing of a heating indoor wall and door in Embodiment 1 of this invention The perspective view of the high frequency heating apparatus in Embodiment 1 of this invention Sectional drawing of the heating indoor wall and door in Embodiment 2 of this invention Sectional drawing of the heating indoor wall and door in Embodiment 3 of this invention Sectional drawing of the heating indoor wall and door in Embodiment 4 of this invention Sectional drawing of a heating indoor wall and door in Embodiment 5 of this invention Sectional drawing of a heating indoor wall and door in Embodiment 5 of this invention Sectional drawing of a heating indoor wall and door in Embodiment 5 of this invention Sectional drawing of a heating indoor wall and door in Embodiment 5 of this invention Sectional view of heating chamber wall and door of conventional high-frequency heating device

  1st invention has an electromagnetic wave shielding part in at least one of the door or main body of a high frequency heating apparatus which has a door which can be opened and closed partially entering the heating chamber, and the heating chamber wall, the electromagnetic wave shielding part, By using a high-frequency heating device in which the opposite surface of the heating device is inclined with respect to the front surface of the door, the heating chamber wall and the door can be configured so that the heating chamber wall and the door do not come into contact with each other when the door is opened and closed. It is possible to make the gap generated on the surface opposite to the conventional structure smaller than that of the conventional configuration, prevent leakage radio waves and hot air leakage from the inside of the heating chamber, and maintain high radio wave shielding performance and heat insulation performance.

  In the second invention, in particular, the door can be thinned in the thickness direction by utilizing the configuration in which the facing surface of the heating chamber wall and the electromagnetic wave shielding portion of the first invention is inclined with respect to the front surface of the door. it can.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 and 2 illustrate a door having a microwave oven and an electromagnetic wave shielding portion in a first embodiment of the present invention.

  First, the configuration of the present embodiment will be described with reference to FIGS. The overview of the microwave oven is the same as FIG. FIG. 1 is a cross-sectional view of the heating chamber 1 and the door 2 shown in FIG.

  Microwave oven. A heating chamber 1 in which food can be taken in and out by opening and closing the door 2, and a power source and magnetron for heating the food by supplying electromagnetic waves (2450 MHz microwave in this embodiment, wavelength λ is about 120 mm) into the heating chamber 1 And electromagnetic wave supply means 5 made of a waveguide (see FIG. 2).

  On the other hand, the door 2 has a conductor piece 8 cut and raised from the conductor wall surface 7 of the door main body 6 around the door main body 6 made of a metal plate, and the conductor piece 8 is processed by bending it into a bag path shape. Is forming. Furthermore, the conductor pieces 8 are periodically arranged in the x direction in the figure by the conductor wall surface 7, and the electromagnetic wave shielding portion 4 is configured as the entire periodic structure.

  During high-frequency heating cooking, if a high frequency leaks to the outside, it will have an unfavorable effect on the human body. Therefore, it is particularly important to take measures against high frequencies that are about to leak from the gap between the door 2 and the high-frequency heating device body. The electromagnetic wave shielding unit 4 is provided.

  The principle of the choke structure of the electromagnetic wave shielding unit 4 is that a high frequency which is about to leak from a gap between the door 2 and the high frequency heating device main body (a gap formed on the facing surface between the heating chamber wall 3 and the electromagnetic wave shielding unit 4 of the door 2). Is introduced into the choke-structured bag path, reflected at the end of the bag path, and the reflected wave and the high-frequency wave guided into the bag path are combined to maximize the high-frequency voltage and minimize the current at the choke structure entrance 9. It is what you use.

  In other words, the apparent impedance is made infinite (∞) by maximizing the high-frequency voltage at the entrance portion 9 of the choke structure and minimizing the current, so that the high-frequency voltage from the gap between the door 2 and the high-frequency heating device body can be reduced. The amount of leakage is eliminated or reduced.

  Therefore, in such a choke structure, the distance from the gap between the door 2 and the main body of the high-frequency heating device to the entrance portion 9 of the choke structure and the distance from the entrance portion 9 of the choke structure to the end of the bag path are as follows: These are set so that the wavelength is about 1/4 of the used frequency, and the reflected wave and the high frequency to be leaked are synthesized in opposite phases at the entrance portion 9 of the choke structure. Yes.

  The shape of the gap is narrow in the z direction and wide in the x and y directions. When the electromagnetic wave is considered as a combined vector in the x, y, and z directions, the x direction component and the y direction component become large and the z direction component can be ignored. Therefore, in order to shield the electromagnetic wave to the outside, the x-direction component and the y-direction component must be shielded.

  However, if the y-direction component can be completely reduced to 0, it will not propagate to the outside. In this case, the x-direction component does not have to be taken care of. Based on this idea, the choke structure is designed.

  In addition, as shown in FIG. 1, the door 2 is partially inserted into the heating chamber 1, thereby preventing hot air from leaking when using the oven function and the convection function, and maintaining high heat insulation performance. ing.

  About the high frequency heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  In the yz plane in FIG. 1, the facing surface of the heating chamber 1 and the electromagnetic wave shielding portion 4 of the door 2 is inclined with respect to the front surface of the door 2, thereby heating the door 2 and the door 2 when the door is opened and closed. By designing so that the indoor wall 3 does not contact, the gap which arises in the opposing surface of the heating chamber 1 and the door 2 can be made smaller than the conventional structure. Therefore, leakage radio waves and hot air leakage from the heating chamber 1 can be prevented, and high radio wave shielding performance and heat insulation performance can be maintained.

  In addition, the angle of the opposing surface with respect to the front surface of the door 2 in the yz plane of FIG. 1 is not limited to a specific angle, but is a design element that should be determined by desired radio wave shielding performance and heat insulation performance. .

  Further, the dimensions of a and b (L = a + b) in FIG. 10 greatly affect the radio wave shielding performance of the electromagnetic wave shielding unit 4. For this reason, in the conventional structure, when designing the door, it is necessary to ensure the dimensions necessary for configuring the electromagnetic wave shielding portion 4 in the door thickness direction, so the door thickness is equal to or greater than the dimension (L) of the electromagnetic wave shielding portion 4. The door 2 must be thinned in the thickness direction.

  However, by configuring the facing surface of the heating chamber wall 3 and the electromagnetic wave shielding portion 4 of the door 2 to be inclined with respect to the front surface of the door 2, the thickness in the door thickness direction can be reduced as compared with the conventional configuration. It becomes possible.

  Moreover, the electromagnetic wave shielding part 4 can be configured not on the door 2 side but on the heating chamber 1 side.

(Embodiment 2)
FIG. 3 illustrates a microwave oven and an electromagnetic wave shielding unit according to the second embodiment of the present invention.

  In the first embodiment, only the structure in which a part of the door 2 enters the inside of the heating chamber 1 in the thickness direction of the door 2 is described. However, the entire door is placed in the heating chamber 1 in the thickness direction as shown in FIG. Even in the case of entering, the same effect as in the first embodiment is obtained by configuring the facing surfaces of the heating chamber 1 and the door 2 to be inclined with respect to the front surface of the door 2 as in the first embodiment. It is possible.

(Embodiment 3)
FIG. 4 illustrates a microwave oven and an electromagnetic wave shielding unit according to the third embodiment of the present invention.

  As shown in FIG. 4, even when the door 2 covers a part or the entire periphery of the heating chamber 1 and has a choke structure on the inner periphery of the heating chamber 1, the front surface of the door 2 is the same as in the first embodiment. By configuring the facing surfaces of the heating chamber 1 and the door 2 to be inclined, it is possible to obtain the same effect as in the first embodiment.

(Embodiment 4)
FIG. 5 illustrates a microwave oven and an electromagnetic wave shielding unit according to the fourth embodiment of the present invention.

  Even in the case of having a choke structure on the outside of the heating chamber 1 as shown in FIG. 5, the opposing surfaces of the heating chamber 1 and the door 2 are inclined with respect to the front surface of the door 2 as in the first embodiment. It is possible to obtain the same effect as in the first embodiment.

(Embodiment 5)
6, FIG. 7, FIG. 8, and FIG. 9 are for explaining the microwave oven and electromagnetic wave shielding unit 4 in the fifth embodiment of the present invention.

  In the first, second, third, and fourth embodiments, as shown in FIGS. 1 and 10, the electromagnetic wave travels about a quarter wavelength 10 from the entrance portion 9 of the choke structure toward the inside of the heating chamber 1, and then reflects at the end of the choke structure. It is the composition to do.

  However, even in the case of the configuration in which the electromagnetic wave travels through the quarter wavelength 10 from the entrance portion 9 of the choke structure in the direction perpendicular to the electromagnetic wave leakage direction as shown in FIG. As in the case of 1, the opposite surface of the heating chamber 1 and the door 2 is inclined with respect to the front surface of the door 2, so that the same effect as that of the first embodiment can be obtained.

  Further, even in the case of a configuration in which electromagnetic waves propagate from the entrance portion 9 of the choke structure toward the outer side of the heating chamber 1 as shown in FIGS. As in the case of 1, the opposite surface of the heating chamber 1 and the door 2 is inclined with respect to the front surface of the door 2, so that the same effect as that of the first embodiment can be obtained.

  Further, as shown in FIG. 9, the electromagnetic wave is reflected at the end of the choke structure after traveling about a quarter wavelength 10 from the entrance portion 9 of the choke structure in a direction perpendicular to the electromagnetic wave leakage direction and inward of the heating chamber 1. Even in this case, it is possible to obtain the same effect as in the first embodiment by configuring the facing surfaces of the heating chamber 1 and the door 2 to be inclined with respect to the front surface of the door 2 as in the first embodiment. It is.

  The present invention relates to a radio wave sealing performance for a high-frequency heater. In particular, when applied to a device having a door that can be opened and closed, such as a microwave oven, the effect can be particularly exerted.

DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Door 3 Heating chamber wall 4 Electromagnetic wave shielding part 5 Electromagnetic wave supply means 6 Door main body 7 Conductor wall surface 8 Conductor piece 9 Choke structure entrance part 10 About 1/4 wavelength

Claims (2)

At least one of the door or the main body of the high-frequency heating device having a freely openable / closable door partially entering the heating chamber has an electromagnetic wave shielding portion, and the surface facing the heating chamber wall and the electromagnetic wave shielding portion is the front surface of the door A high-frequency heating device that is slanted with respect to. The high-frequency heating device according to claim 1, wherein the opposing surface between the heating chamber wall and the electromagnetic wave shielding portion is inclined with respect to the front surface of the door, thereby reducing the thickness in the door thickness direction.