WO2023063135A1

WO2023063135A1 - Refrigerator

Info

Publication number: WO2023063135A1
Application number: PCT/JP2022/036921
Authority: WO
Inventors: 貴代志森; 桂南部; 範幸米野
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2021-10-12
Filing date: 2022-10-03
Publication date: 2023-04-20
Also published as: JP2023057842A

Abstract

This refrigerator has: a shield case in which an opening is provided to the front side and which is fabricated from a metal material; a flat first electrode disposed within the shield case; a flat second electrode disposed within the shield case so as to face the first electrode with spacing therebetween, the second electrode forming a heating space for dielectrically heating a food product located between the first and second electrodes, and being connected to ground; and an oscillation part for generating an AC voltage to be applied between the first and second electrodes. The facing-direction distance D between the first and second electrodes, the output electric power W of the oscillation part, the output impedance Z of the oscillation part, and the distance D1 from the front end of the second electrode to the opening in the shield case satisfy the given formula.

Description

refrigerator

The present invention relates to a refrigerator that can dielectrically heat food.

For example, Patent Document 1 discloses a freezer that can thaw frozen food. The freezer of Patent Document 1 has a high-frequency heating chamber in which food to be thawed is accommodated and in which high-frequency heating (dielectric heating) is performed on the accommodated food. The high-frequency heating chamber is configured to be able to introduce cold air from the freezer compartment. This allows the high-frequency heating chamber to be used as a freezing chamber when not used for defrosting.

JP-A-2002-147919

By the way, when food is dielectrically heated as in Patent Document 1, it is necessary to suppress leakage of the alternating electric field used for the dielectric heating to the outside.

Therefore, an object of the present invention is to suppress leakage of an alternating electric field from the heating space of a refrigerator that dielectrically heats food to the outside.

According to one aspect of the present invention,
a shield case made of a metal material and having an opening on the front side that communicates between the inside and the outside;
a flat plate-like first electrode arranged in the shield case;
A plate-shaped plate disposed in the shield case so as to face the first electrode with a gap, forming a heating space for dielectrically heating food between the first electrode and the first electrode, and connected to the ground a second electrode of
an oscillation unit that generates an alternating voltage to be applied between the first electrode and the second electrode;
The distance D between the first electrode and the second electrode in the facing direction, the output power W of the oscillator, the output impedance Z of the oscillator, and the opening of the shield case from the front end of the second electrode The distance D1 to

A refrigerator is provided to satisfy

According to the present invention, leakage of an alternating electric field to the outside from the heating space of a refrigerator that dielectrically heats food can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS Longitudinal sectional view of a refrigerator according to one embodiment of the present invention Block diagram showing the control system of a refrigerator Perspective view of heating module Cross section of heating module Sectional view of the heating module along line AA shown in FIG. Block diagram showing the control system of the heating module Figure showing the simulation result of the spread of the alternating electric field in the front-back direction A diagram showing the simulation result of the horizontal spread of the alternating electric field. Partial longitudinal sectional view of a refrigerator according to another embodiment of the present invention

A refrigerator according to an aspect of the present invention includes a shield case having an opening on the front side that communicates between the inside and the outside, the shield case being made of a metal material, and a flat plate-like first electrode arranged in the shield case. a flat plate arranged in the shield case so as to face the first electrode with a gap, forming a heating space between the first electrode and the first electrode for dielectrically heating food, and connected to the ground; and an oscillator for generating an alternating voltage to be applied between the first electrode and the second electrode, wherein the first electrode and the second electrode , the output power W of the oscillator, the output impedance Z of the oscillator, and the distance D1 from the front end of the second electrode to the opening of the shield case,

satisfy.

According to this aspect, leakage of the alternating electric field to the outside from the heating space of the refrigerator that dielectrically heats the food can be suppressed.

For example, the front end of the first electrode may be further away from the opening of the shield case than the front end of the second electrode. This makes it possible to further suppress leakage of the alternating electric field to the outside.

For example, the facing direction distance D, the output power W, the impedance Z, and the distance D2 from the side end of the second electrode to the inner wall surface of the shield case are

satisfy. This suppresses the formation of capacitance between the side end of the second electrode and the inner wall surface of the shield case. As a result, the dielectric heating efficiency of food is improved.

For example, the side edge of the first electrode may be farther from the inner wall surface of the shield case than the side edge of the second electrode. This suppresses the formation of capacitance between the side end of the first electrode and the inner wall surface of the shield case. As a result, the dielectric heating efficiency of food is improved.

For example, the heating space may be at least part of a freezer compartment that freezes food. As a result, frozen food can be thawed as it is.

A refrigerator according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the refrigerator according to Embodiment 1. FIG. In FIG. 1, the left side is the front side of the refrigerator and the right side is the rear side of the refrigerator. FIG. 2 is a block diagram showing the control system of the refrigerator. The XYZ orthogonal coordinate system shown in the drawings is for facilitating understanding of the embodiments according to the present invention, and does not limit the embodiments. The X-axis direction indicates the front-rear direction (depth direction) of the refrigerator 10, the Y-axis direction indicates the left-right direction (width direction), and the Z-axis direction indicates the vertical direction (height direction).

As shown in FIG. 1, refrigerator 10 includes main body 12 . The main body 12 includes an outer housing 14 that is made of a metal material and constitutes the outer surface of the refrigerator 10, an inner housing 16 that is made of a resin material such as ABS and constitutes the inner surface of the refrigerator 10, and an outer housing. The space between the body 14 and the inner housing 16 is filled with a heat insulating material 18 such as rigid urethane foam.

The main body 12 of the refrigerator 10 has a plurality of storage chambers for storing food (ingredients, processed foodstuffs, etc.). In the case of the present embodiment, storage chambers are provided from the top with a refrigerating chamber 12a, a freezing/thawing chamber 12b, a freezing chamber 12c, and a vegetable chamber 12d. In addition, in the case of this embodiment, the freeze/thaw chamber 12b and the freezer chamber 12c are in communication with each other.

The refrigerator compartment 12a is a space that maintains a temperature range in which food does not freeze, for example, a temperature range of 1°C to 5°C. The freezing/thawing chamber 12b and the freezing chamber 12c are spaces maintained in a temperature range in which food is frozen, for example, a temperature range of -22°C to -15°C. The freezing/thawing chamber 12b, which will be described later in detail, can not only freeze food but also heat food, for example, thaw frozen food. The vegetable compartment 12d is a space maintained in a temperature range equal to or higher than the temperature range of the refrigerator compartment 12a, for example, a temperature range of 2°C to 7°C. In addition to these spaces, the refrigerator 10 may be provided with semi-freezing spaces at -1°C or -3°C.

In the case of this embodiment, a machine room 12e is provided in the upper part of the main body 12 of the refrigerator 10. The machine room 8 houses a compressor 20 that constitutes a refrigerating cycle of the refrigerator 10 and circulates the refrigerant of the refrigerating cycle. Alternatively, the machine room 12e can be provided in the lower part of the main body 12 of the refrigerator 10.

In the case of this embodiment, a cooling chamber 12f is provided behind the freezer compartment 12c and the vegetable compartment 12d. Inside the cooling chamber 12f, a cooler 22 that forms a refrigerating cycle of the refrigerator 10 and through which a refrigerant passes is arranged. A cooling fan 24 blows the air (cold air) in the cooling chamber 12f cooled by the cooler 22 toward the refrigerating chamber 12a, the freezing/thawing chamber 12b, the freezing chamber 12c, and the vegetable chamber 12d to the cooling chamber 12f. is provided.

In the case of this embodiment, the refrigerator 10 is provided with three doors 12g to 12i. The door 12g can be opened and closed, and connects or disconnects the refrigerator compartment 12a and the outside. Moreover, the door 12h can be opened and closed, and connects or separates the freezing/thawing chamber 12b and the freezing chamber 12c from the outside. The door 12i can be opened and closed, and connects or separates the vegetable compartment 12d and the outside.

Furthermore, as shown in FIG. 2, dampers 26A to 26C for controlling the flow rate of cold air flowing into each chamber 12a to 12d are arranged in the flow path between each chamber 12a to 12d and the cooling fan 24 (see FIG. 2). 1 shows only the damper 26B). A damper 26B is arranged in the flow path between the freezing/thawing chamber 12b and the cooling fan 24. As shown in FIG. Cold air passes through freeze/thaw compartment 12b and flows into freezer compartment 12c.

Furthermore, as shown in FIG. 2, the refrigerator 10 includes temperature sensors 28A to 28C that measure the internal temperatures of the refrigerating compartment 12a, the freezing/thawing compartment 12b, the freezing compartment 12c, and the vegetable compartment 12d.

As shown in FIG. 2, the control unit 30 of the refrigerator 10 executes cooling control based on the measurement results of the plurality of temperature sensors 28A to 28C. , and dampers 26A to 26C, the temperatures in refrigerator compartment 12a, freeze/thaw compartment 12b, freezer compartment 12c, and vegetable compartment 12d are appropriately maintained. The control unit 30 is, for example, a control board that is arranged in the machine room 12e and includes a processor such as a CPU, a storage device such as a memory that stores programs, and a circuit. A processor controls compressor 20, cooling fan 24, and dampers 26A-26C according to a program stored in a memory device.

In addition, as shown in FIG. 1, the refrigerator 10 includes door opening/closing sensors 32A to 32C that detect the opening/closing states of the plurality of doors 12g to 12i, respectively. The door opening/closing sensors 32A-32C are, for example, switches that detect the closed doors 12g-12i by coming into contact with the doors 12g-12i. The door open/close sensors 32A-32C are provided at positions on the main body 12 of the refrigerator 10 where they can come into contact with the inner surfaces of the doors 12g-12i. Further, detection signals of the door opening/closing sensors 32A to 32C are transmitted to the control section 30. FIG. For example, based on detection signals from door opening/closing sensors 32A to 32C, the control unit 30 controls lighting devices (not shown) provided in each of the refrigerator compartment 12a, the freeze/thaw compartment 12b, the freezer compartment 12c, and the vegetable compartment 12d. is ON/OFF controlled. The switch may be a mechanical switch, or a magnetic sensor such as a Hall sensor, that is, a non-contact switch. Magnetic sensors such as Hall sensors, MR sensors, and reed switches have the advantages of being easier to be miniaturized than mechanical switches and not impairing the design of refrigerator 10 because they do not have projections.

As shown in FIG. 2, in the case of the present embodiment, refrigerator 10 includes a user interface 34 for the user to operate refrigerator 10 . The user interface 34 may be a touch panel or the like built into the refrigerator 10 and/or may be the user's mobile device. When the user interface 34 is a mobile terminal, software (application) for operating the refrigerator 10 is installed in the mobile terminal.

For example, when one of the door opening/closing sensors 32A to 32C detects that the corresponding door 12g to 12i is open for a predetermined time, the user interface 34 notifies the user that the door is open. The user interface 34 is also used by the user when performing thawing in the freeze/thaw compartment 12b. Details of the freezing/thawing chamber 12b will now be described.

FIG. 3 is a perspective view of the heating module. 4 is a cross-sectional view of the heating module, and FIG. 5 is a cross-sectional view of the heating module taken along line AA shown in FIG. FIG. 6 is a block diagram showing the control system of the heating module.

In the case of the present embodiment, the heating module 40 shown in FIGS. 3 to 5 is a module that heats frozen food and is incorporated in the refrigerator 10. Freeze/thaw chamber 12 b is provided within heating module 40 . Although details will be described later, the heating module 40 is configured to generate an alternating electric field in the freezing/thawing chamber 12b and dielectrically heat the food by the alternating electric field.

As shown in FIGS. 3 to 5, the heating module 40 has a rectangular parallelepiped shape and is a double-walled structure including an inner case 42 and a shield case 44 that houses the inner case 42 . The shield case 44 functions as a housing for the heating module 40 . The inner case 42 defines a storage chamber in which food is stored, that is, a freeze/thaw chamber 12b.

The inner case 42 is a rectangular parallelepiped box made of an insulating material such as resin and provided with an opening on the front side for communication between the inside and the outside. The shield case 44 is made of a metal material, for example, made of a metal material such as aluminum. The shield case 44 is a rectangular parallelepiped box having an opening on the front side for communication between the inside and the outside, and stores the inner case 42 therein.

In the case of this embodiment, as shown in FIG. 3, the heating module 40 includes a drawer 46 that is inserted into and removed from the freezing/thawing chamber 12b in the front-rear direction (X-axis direction) and stores food. The drawer 46 is made from a resin material. Further, as shown in FIG. 5, a guide rail 47 is provided on the inner wall surface 42a of the inner case 42 to guide the drawer 46 in the front-rear direction (X-axis direction) when the drawer 46 is put in and taken out. Such a drawer 46 facilitates the loading and unloading of food from the freeze/thaw chamber 12b.

In addition, the inner case 42 and the shield case 44 of the heating module 40 are provided with a plurality of

ventilation holes

42b, 44a communicating with the freezing/thawing chamber 12b so that the food in the freezing/thawing chamber 12b can be frozen. Cool air that has passed through the damper 26B flows into the freezing/thawing chamber 12b through these

ventilation holes

42b and 44a. Thereby, the food in the heating module 40, that is, in the freezing/thawing chamber 12b can be frozen.

The heating module 40 comprises a first electrode 48 and a second electrode 50 for dielectric heating of food in the freeze/thaw chamber 12b, for example for thawing frozen food.

As shown in FIGS. 4 and 5, the first electrode 48 and the second electrode 50 are plate-shaped members made of a metal material. Also, the first electrode 48 and the second electrode 50 are arranged in the shield case 44 so as to face each other with a space therebetween. In the case of this embodiment, the first electrode 48 and the second electrode 50 face each other in the vertical direction (Z-axis direction) and are parallel to each other. A first electrode 48 and a second electrode 50 facing each other at a distance form therebetween a heating space HZ for dielectric heating of food. A drawer 46 is provided in the heating module 40 such that it can be drawn in and out of the heating space HZ between the first electrode 48 and the second electrode 50 .

In the case of the present embodiment, the first electrode 48 is arranged between the top plate portion 42c of the inner case 42 and the top plate portion 44b of the shield case 44. A space (that is, an air layer) is provided between the shield case 44 and the first electrode 48 .

In the case of this embodiment, the second electrode 50 is arranged on the bottom plate portion 42d of the inner case 42 .

In order to form the heating space HZ between the first electrode 48 and the second electrode 50, the refrigerator 10 is arranged between the first electrode 48 and the second electrode 50 as shown in FIG. An oscillator 52 is provided to generate an AC voltage to be applied. The oscillator 52 is, for example, an oscillator circuit board arranged in the machine room 12 e of the refrigerator 10 and electrically connected to the first electrode 48 and the second electrode 50 . Oscillator 52 converts an AC voltage from power supply unit 54 of refrigerator 10 connected to a commercial power supply, and applies the converted AC voltage between first electrode 48 and second electrode 50 . Between the first electrode 48 and the second electrode 50, an AC voltage of a predetermined VHF band frequency, eg, 40.68 MHz is applied.

When the oscillator 52 applies an AC voltage between the first electrode 48 and the second electrode 50, an alternating electric field is generated in the shield case 44 (freezing/heating chamber 12b). This alternating electric field dielectrically heats the food to be heated which is housed in the drawer 46 and arranged between the first electrode 48 and the second electrode 50, that is, the food which is arranged in the heating space HZ. be. As a result, the food is dielectrically heated.

In the case of this embodiment, as shown in FIG. 6, the refrigerator 10 has a matching circuit 56 that matches the impedance between the first electrode 48 and the second electrode 50 . Matching circuit 56 is, for example, a circuit board housed in heating module 40 . A matching circuit 56 is electrically connected to the first electrode 48 and the second electrode 50 . In this embodiment, the second electrode 50 is grounded.

The role of the matching circuit 56 will be explained. As the frozen food is thawed, the number of water molecules in the food increases. As the number of water molecules increases, the impedance between the first electrode 48 and the second electrode 50 changes from its proper value and the reflectance increases. The reflectance is the ratio of the reflected wave returning to the oscillator 52 to the incident wave output from the oscillator 52 . As the reflectance increases, the dielectric heating of food becomes less efficient. A matching circuit 56 is provided to maintain the impedance between the first electrode 48 and the second electrode 50 at a proper value.

Specifically, as shown in FIG. 6, the refrigerator 10 includes a reflected wave detection circuit 58 in order for the matching circuit 56 to maintain the impedance between the first electrode 48 and the second electrode 50 at a proper value. Prepare. The reflected wave detection circuit 58 is provided, for example, on a substrate arranged in the machine room 12e of the refrigerator 10 . The control section 30 calculates the reflectance based on the incident wave output from the oscillation section 52 and the reflected wave detected by the reflected wave detection circuit 58 . Based on the calculated reflectance, the control unit 30 controls the matching circuit 56 so that the impedance between the first electrode 48 and the second electrode 50 becomes an appropriate value.

When the user places food to be heated in the heating space HZ of the freezing/thawing chamber 12b and issues a heating instruction to the user interface 34, the control unit 30 causes the oscillation unit 52 to generate a heating start signal to generate an AC voltage. to cause the oscillator 52 to generate an AC voltage. As a result, an alternating voltage is applied between the first electrode 48 and the second electrode 50, an alternating electric field is generated in the shield case 44 (the freezing/thawing chamber 12b), and the food is dielectrically heated by the alternating electric field. be done.

During the heating of food in the heating space HZ, an alternating electric field is generated inside the freezing/thawing chamber 12b. At this time, the shield case 44 shields the alternating electric field and suppresses leakage of the alternating electric field to the outside of the shield case 44 (freezing/thawing chamber 12b). In order to suppress leakage of the alternating electric field through the opening 44c on the front side of the shield case 44, the door 12h is provided with a metal shield plate 12j covering the opening 44c of the shield case 44, as shown in FIG. is provided.

Further, when the door 12h is not completely closed and the alternating electric field can leak outside, the application of the AC voltage between the first electrode 48 and the second electrode 50 by the oscillator 52 is prohibited. ing. That is, the oscillator 52 can generate an AC voltage only when the door opening/closing sensor 32B detects the closed door 12h. In the case of the present embodiment, when the control unit 30 receives a thawing instruction from the user via the user interface 34, if the door opening/closing sensor 32B detects the closed door 12h, the oscillation unit A heating start signal is output to 52 . On the other hand, if the door open/close sensor 32B has not detected the closed door 12h when receiving the user's thawing instruction, the control unit 30 does not output the heating start signal to the oscillation unit 52, The user is notified via the user interface 34 to close the door 12h.

Furthermore, in the case of the present embodiment, if the door 12h is opened while the oscillator 52 is generating AC voltage (that is, the food is being dielectrically heated), the door opening/closing sensor 32B cannot detect the closed door 12h. , the oscillator 52 that is generating the AC voltage stops generating the AC voltage. In the case of the present embodiment, control unit 30 outputs a heating stop signal to oscillation unit 52, thereby causing oscillation unit 52 to stop generating AC voltage.

The AC voltage generation control of the oscillator 52 based on the open/closed state of the door 12h suppresses leakage of the alternating electric field to the outside of the shield case 44 (freezing/thawing chamber 12b). Further, in the case of the present embodiment, the door open/close sensor 32B is a switch that detects the closed state of the door 12h by contacting the door 12h and is located outside the shield case 44. It is less susceptible to the generated alternating electric field. As a result, leakage of the alternating electric field to the outside of the shield case 44 is reliably suppressed.

In addition, in the case of this embodiment, the heating module 40 further has a drawer detection sensor 60 that detects the drawer 46, as shown in FIG. Specifically, the drawer detection sensor 60 detects the drawer 46 when the drawer 46 exists at a predetermined position between the first electrode 48 and the second electrode 50 . The "predetermined position" referred to here is the position of the drawer 46 when the food to be heated stored in the drawer 46 is placed in the heating space HZ between the first electrode 48 and the second electrode 50. say the location. For this purpose, as shown in FIG. 3, a bottom surface 46a of the drawer 46 is provided with a marker 46b for presenting the user with the placement position of the food to be heated. That is, when the food to be heated is placed on the marker 46b and the drawer 46 is placed in a predetermined position, the food to be heated is placed in the heating space HZ between the first electrode 48 and the second electrode 50. and is properly dielectrically heated.

In the case of the present embodiment, the drawer detection sensor 60 is a mechanical sensor provided at the opening edge 42e of the inner case 42 and in contact with the front end 46c of the drawer 46, as shown in FIGS. As a result, the drawer detection sensor 60 is provided outside the freezing/thawing chamber 12 b , that is, outside the shield case 44 . This allows the drawer detection sensor 60 to reliably detect the drawer 46 .

Unlike this, if the drawer detection sensor 60 is provided inside the freezing/thawing chamber 12b, that is, inside the shield case 44 where the alternating electric field is generated, the drawer sensor 60 may erroneously detect the drawer 46. For example, if the drawer sensor 60 is a Hall sensor that detects a magnetic field, it may malfunction due to an alternating electric field (magnetic field) generated inside the shield case 44 . Further, for example, if the drawer sensor 60 is a mechanical sensor, the contact surface of the drawer detection sensor 60 and the contact surface of the drawer 46 may stick to each other through ice. Also, the moving parts of the drawer detection sensor 60 may freeze and become unable to move properly. Therefore, the drawer detection sensor 60 is provided outside the radio wave irradiation space of the freezing/thawing chamber 12 b , that is, outside the space between the first electrode 48 and the second electrode 50 .

In the case of the present embodiment, the oscillator 52 is enabled to generate AC voltage only when the drawer detection sensor 60 detects the drawer 46 existing at a predetermined position. In this embodiment, the drawer detection sensor 60 is electrically connected to the oscillator 52 . While the oscillator 52 receives a detection signal from the drawer detection sensor 60 indicating that the drawer 46 exists at a predetermined position, the oscillator 52 waits in a state in which an AC voltage can be generated. Upon receiving a heating start signal from the control unit 30, the oscillation unit 52 in the standby state starts generating AC voltage. On the other hand, while the detection signal is not received from the drawer detection sensor 60 , the oscillation section 52 does not generate an AC voltage even if the heating start signal is received from the control section 30 .

Therefore, in the present embodiment, the door opening/closing sensor 32B detects the closed door 12h, and the drawer detection sensor 60 detects the drawer 46 existing at a predetermined position. When in the state, the oscillator 32 generates an alternating voltage to be applied between the first electrode 48 and the second electrode 50 . As a result, even when the door 12h is closed, the drawer 46 does not exist in a predetermined position, so that the food to be heated is placed in the heating space HZ between the first electrode 48 and the second electrode 50. is not properly positioned, the onset of dielectric heating is inhibited. As a result, insufficient thawing of food and wasteful power consumption are suppressed.

When the drawer 46 is pulled out from a predetermined position while the oscillator 52 is generating AC voltage (that is, during dielectric heating of the food), the AC voltage is generated when the drawer detection sensor 60 becomes unable to detect the drawer 46 existing at the predetermined position. The oscillator 52 that is generating the voltage stops generating the AC voltage. In the case of this embodiment, when the detection signal from the drawer detection sensor 60 can no longer be received, the oscillator 52 stops generating the AC voltage.

In the case of the present embodiment, the door 12h must first be opened in order to pull out the drawer 46 from the predetermined position while the oscillator 52 is generating AC voltage (that is, during the dielectric heating of the food). Therefore, when the door 12h is opened, the door opening/closing sensor 32B cannot detect the closed door 12h, and the oscillator 52 stops generating the AC voltage.

However, even though the door 12h is open, the oscillator 52 may generate AC voltage for some reason, for example, due to an erroneous detection of the door open/close sensor 32B. In this case, when the drawer 46 is pulled out from the predetermined position and the drawer detection sensor 60 cannot detect the drawer 46 existing at the predetermined position, the oscillator 52 stops generating the AC voltage.

As shown in FIG. 4, the drawer detection sensor 60 is provided outside the freezing/thawing chamber 12b, that is, at the opening edge 42e of the inner case 42, and detects (contacts) the front end 46c of the drawer 46. The drawer detection sensor 60 can also be provided at a position other than the opening edge 42 e of the inner case 42 . That is, the drawer detection sensor 60 should be located at a position where it can detect the drawer 46 arranged at a predetermined position. However, it is preferable to arrange the drawer detection sensor 60 at a position where the drawer detection sensor 60 itself and wiring such as signal lines extending from the sensor are not greatly affected by the alternating electric field generated in the shield case 44 . This suppresses malfunction of the drawer detection sensor 60 due to the alternating electric field.

Regarding the influence of the alternating electric field, as shown in FIG. It is less susceptible to the alternating electric field generated inside. This prevents the door open/close sensor 32B, the controller 30, and the oscillator 52 from malfunctioning due to the alternating electric field.

Furthermore, even though the door 12h is open and the drawer 46 is not in the predetermined position, the oscillator 52 may generate AC voltage for some reason. In order to suppress leakage of the alternating electric field to the outside of the shield case 44 (freezing chamber/heating chamber 12b), the positions of the first electrode 48 and the second electrode 50 in the shield case 44 are defined. . Specifically, as shown in FIG. 4, a distance D1 from the front end 50a of the second electrode 50 to the opening 44c of the shield case 44 is defined. This distance D1 will be specifically described.

FIG. 7A is a diagram showing a simulation result of the spread of the alternating electric field in the front-rear direction. FIG. 7B is a diagram showing a simulation result of horizontal expansion of the alternating electric field.

As shown in FIG. 7A, the alternating electric field generated by the AC voltage applied between the first electrode 48 and the second electrode 50 spreads in the front-rear direction (X-axis direction) inside the shield case 44 . Also, as shown in FIG. 7B, an alternating electric field generated by the AC voltage applied between the first electrode 48 and the second electrode 50 spreads in the shield case 44 in the horizontal direction (Y-axis direction).

The electric field strength E [V/mm] of the alternating electric field generated between the first electrode 48 and the second electrode 50 is, as shown in Equation 1, the difference between the first electrode 48 and the second electrode 50 It can be simply represented by the voltage V [V] between the first electrode 48 and the second electrode 50 and the distance D [mm] in the opposing direction (Z-axis direction) between the first electrode 48 and the second electrode 50 .

The voltage V can be expressed by Equation 2 using the output power W [w] of the oscillator 52 and the impedance Z [Ω]. The impedance Z is a target impedance value to be adjusted by the matching circuit 56 and is a fixed value. By equalizing the output impedance of the oscillator 52 and the impedance Z adjusted by the matching circuit 56, reflection of radio waves can be suppressed. For example, impedance Z is typically 50Ω.

Therefore, the electric field intensity E can be expressed as in Equation 3.

The inventor has established a conditional expression for suppressing leakage of an alternating electric field generated by applying an alternating voltage between the first electrode 48 and the second electrode 50 to the outside of the shield case 44 through the opening 44c. , Equation 4 was found by experiment.

A distance D1 from the front end 50a of the second electrode 50 to the opening 44c of the shield case 44 is determined based on the output power W and the output impedance Z of the oscillator 52 so as to satisfy Equation 4. The distance D1 determined in this way can suppress leakage of the alternating electric field to the outside of the shield case 44, that is, the freezing/heating chamber 12b.

For example, when the impedance Z (the output impedance of the oscillation unit 52) is 50Ω, the output power W is 100W, and the distance D between the electrodes is 100mm, D1 is larger than 17.67mm. Leakage of the alternating electric field to the outside of the chamber 12b can be suppressed.

As shown in FIGS. 4 and 7A, a relatively high intensity electric field is generated near the front end 48a of the first electrode 48, which is the end of the shield case 44 near the opening 44c. This occurs because the first electrode 48, unlike the second electrode 50, is an electrode that is not connected to ground. In order to prevent such a relatively high-intensity electric field from leaking out of the shield case 44 through the opening 44c of the shield case 44, as shown in FIG. It is farther from the opening 44c of the shield case 44 than the front end 50a of the second electrode 50 is.

In the case of the present embodiment, as shown in FIG. 5, the distance D2 from the left-right direction (Y-axis direction) side end 50b of the second electrode 50 to the inner wall surface 44d of the shield case 44 is also equal to the distance D1. similarly stipulated. The distance D2 is determined based on the output power W and the output impedance Z of the oscillation section 52 so as to satisfy Equation 5, like the distance D1.

Equations 4 and 5 for determining the distance D1 and the distance D2 are the same. However, unlike Expression 4, Expression 5 is not a conditional expression for suppressing leakage of the alternating electric field to the outside of shield case 44 . Equation 5 is a conditional expression for suppressing formation of capacitance between the side end 50 b of the second electrode 50 and the inner wall surface 44 d of the shield case 44 . If the distance D2 does not satisfy Equation 5, a large capacitance is formed between the side end 50b of the second electrode 50 and the inner wall surface 44d of the shield case 44. That is, the electric field generated at the side end 50b of the second electrode 50 reaches the inner wall surface 44d of the shield case 44. As shown in FIG. As a result, radio waves leak through the shield case 44, and part of the output power of the oscillator 52 is wasted for purposes other than generating the alternating electric field for dielectrically heating the food. This reduces the efficiency of dielectric heating of food. In order to suppress such radio wave leakage and dielectric heating efficiency reduction, the distance D2 is determined so as to satisfy Equation (5).

In addition, in the case of the present embodiment, a relatively high intensity electric field is generated in the vicinity of the side end 48b of the first electrode 48, as shown in FIGS. 5 and 7B. If the side edge 48b of the first electrode 48, which generates such a relatively high-intensity electric field, comes too close to the inner wall surface 44d of the shield case 44, there will be a large gap between the side edge 48b and the inner wall surface 44d. A large capacity is formed. The side edge 48b of the first electrode 48 is farther from the inner wall surface 44d of the shield case 44 than the side edge 50b of the second electrode 50 so as not to form a very large capacitance.

According to the present embodiment as described above, leakage of an alternating electric field to the outside from the heating space of a refrigerator that dielectrically heats food can be suppressed.

Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

For example, as shown in FIG. 1, the door 12h and the drawer 46 are not connected in the above embodiment. However, embodiments of the present invention are not limited to this.

FIG. 8 is a longitudinal sectional view of part of a refrigerator according to another embodiment of the present invention.

As shown in FIG. 8, in a refrigerator 110 according to another embodiment, a door 112h that connects or separates the heating space HZ and the outside of the shield case 44 is connected to a drawer 46 that can be put into and taken out of the heating space HZ. ing. Therefore, when the door 112h opens, the drawer 46 moves forward. In this case, the door 112h is not a door that rotates about a rotation center line extending in the vertical direction (Z-axis direction), but a door that can move in parallel in the front-rear direction (X-axis direction). Also, in this embodiment, the drawer detection sensor is omitted. Instead, the door opening/closing sensor 32B functions not only to detect opening/closing of the door 112h, but also as a drawer detection sensor.

Also, in the case of the above embodiment, as shown in FIG. 5, the heating space HZ for thawing food is a part of the freeze/thaw chamber 12b for freezing food. However, embodiments of the present invention are not limited to this. The entire freezing/thawing chamber 12b may be the heating space HZ.

Furthermore, in the case of the above embodiment, the first electrode 48 and the second electrode 50 face each other in the vertical direction (Z-axis direction), as shown in FIGS. Also, the second electrode 50 located on the lower side is connected to the ground as shown in FIG. However, this embodiment is not limited to this. For example, the first electrode and the second electrode may face each other in the vertical direction, and the upper first electrode may be connected to the ground. Further, for example, the first electrode and the second electrode may face each other in the left-right direction (the width direction of the refrigerator).

Furthermore, in the case of the above embodiment, the heating module 40 is provided with the freezing/thawing chamber 12b. In other words, the heating module 40 is configured to permit food to be stored frozen in addition to dielectrically heating the food. However, embodiments of the present invention are not limited to this. Heating module 40 may be used only for dielectric heating of food products. In this case, there is no need to introduce cold air into the heating module 40 .

That is, in a broad sense, the refrigerator according to the embodiment of the present invention includes a shield case having an opening on the front side that communicates the inside and the outside, made of a metal material, and a flat plate disposed in the shield case. A first electrode having a shape and a heating space disposed in the shield case so as to face the first electrode with a gap, and forming a heating space for dielectrically heating food between the first electrode and the first electrode, and a flat plate-like second electrode connected to the ground, and an oscillator for generating an AC voltage applied between the first electrode and the second electrode, wherein the first electrode and the second electrode, the output power W of the oscillator, the output impedance Z of the oscillator, and the distance D1 from the front end of the second electrode to the opening of the shield case ,

satisfy.

The present invention is applicable to refrigerators that can dielectrically heat food.

Claims

a shield case made of a metal material and having an opening on the front side that communicates between the inside and the outside;
a flat plate-like first electrode arranged in the shield case;
A plate-shaped plate disposed in the shield case so as to face the first electrode with a gap, forming a heating space for dielectrically heating food between the first electrode and the first electrode, and connected to the ground a second electrode of
an oscillation unit that generates an alternating voltage to be applied between the first electrode and the second electrode;
The distance D between the first electrode and the second electrode in the facing direction, the output power W of the oscillator, the output impedance Z of the oscillator, and the opening of the shield case from the front end of the second electrode The distance D1 to

A refrigerator that satisfies.
2. The refrigerator according to claim 1, wherein the front end of said first electrode is farther from said opening of said shield case than the front end of said second electrode.
The facing direction distance D, the output power W, the impedance Z, and the distance D2 from the side end of the second electrode to the inner wall surface of the shield case are

3. The refrigerator according to claim 1 or 2, which satisfies
4. The refrigerator according to claim 3, wherein a side edge of said first electrode is further away from an inner wall surface of said shield case than a side edge of said second electrode.
The refrigerator according to any one of claims 1 to 4, wherein the heating space is at least part of a freezer compartment that freezes food.