CN118043614A - Refrigerator with a refrigerator body - Google Patents

Abstract

The refrigerator includes: a shield case made of a metal material and having an opening on a front side; a flat first electrode disposed in the shield case; a grounded flat-plate-shaped second electrode disposed in the shield case so as to face the first electrode with a gap therebetween, and forming a heating space between the second electrode and the first electrode for dielectric heating of the food; and an oscillating portion that generates an alternating voltage for application between the first electrode and the second electrode. The relative direction distance D of the first electrode and the second electrode, the output power W of the oscillating portion, the output impedance Z of the oscillating portion, and the distance D1 from the front end of the second electrode to the opening portion of the shield case satisfy the following mathematical expression:

Description

Refrigerator with a refrigerator body

Technical Field

The present invention relates to a refrigerator capable of dielectric heating of food.

Background

For example, patent document 1 discloses an ice bin capable of thawing food in a frozen state. The refrigerator of patent document 1 has a high-frequency heating chamber for storing food to be defrosted and heating the stored food at high frequency (dielectric heating). The high-frequency heating chamber is configured to be capable of introducing cool air of the freezing chamber. Thus, the high-frequency heating chamber can be used as a freezing chamber without being used for thawing.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2002-147919

Disclosure of Invention

Technical problem to be solved by the invention

However, when the food is subjected to dielectric heating as in patent document 1, leakage of an alternating electric field used for the dielectric heating to the outside needs to be suppressed.

Therefore, the present invention has an object to suppress leakage of an alternating electric field from a heating space of a refrigerator for dielectric heating of food to the outside.

Technical means for solving the problems

According to one aspect of the present invention, there is provided a refrigerator including:

a shield shell made of a metal material having an opening portion on a front side communicating an inside and an outside;

a flat plate-shaped first electrode disposed in the shield case;

A flat-plate-shaped second electrode disposed in the shield case so as to face the first electrode with a gap therebetween, the second electrode being grounded, and a heating space for dielectric heating of the food being formed between the second electrode and the first electrode; and

An oscillating portion for generating an alternating voltage to be applied between the first electrode and the second electrode,

The relative direction distance D of the first electrode and the second electrode, the output power W of the oscillating portion, the output impedance Z of the oscillating portion, and the distance D1 from the front end of the second electrode to the opening portion of the shield case satisfy the following mathematical expression:

Effects of the invention

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

Drawings

Fig. 1 is a longitudinal sectional view of a refrigerator according to an embodiment of the present invention.

Fig. 2 is a block diagram illustrating a control system of a refrigerator.

Fig. 3 is a perspective view of a heating assembly.

Fig. 4 is a cross-sectional view of a heating assembly.

Fig. 5 is a cross-sectional view of the heating assembly taken along line A-A of fig. 4.

FIG. 6 is a block diagram illustrating a control system for a heating assembly.

Fig. 7A is a diagram showing simulation results of expansion of an alternating electric field in the front-rear direction.

Fig. 7B is a diagram showing simulation results of expansion of the alternating electric field in the left-right direction.

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

Detailed Description

The refrigerator according to one embodiment of the present invention includes: a shield shell made of a metal material having an opening portion on a front side communicating an inside and an outside; a flat plate-shaped first electrode disposed in the shield case; a flat-plate-shaped second electrode disposed in the shield case so as to face the first electrode with a gap therebetween, the second electrode being grounded, and a heating space capable of dielectric heating (dielectric heating) the food being formed between the second electrode and the first electrode; and an oscillating portion that generates an alternating voltage for application between the first electrode and the second electrode, a relative directional distance D of the first electrode and the second electrode, an output power W of the oscillating portion, an output impedance Z of the oscillating portion, and a distance D1 from a front end of the second electrode to the opening portion of the shield case satisfying the following mathematical expression:

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

For example, the tip of the first electrode may be farther from the opening of the shield case than the tip of the second electrode. This can further suppress leakage of the alternating electric field to the outside.

For example, the relative 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 satisfy the following mathematical expression:

this can suppress 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 the food is improved.

For example, the side end of the first electrode may be farther from the inner wall surface of the shield case than the side end of the second electrode. This can suppress 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 the food is improved.

For example, the heating space may be at least a portion of a freezer that freezes the food product. Thus, the frozen food can be thawed in situ.

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

Fig. 1 is a longitudinal sectional view of the refrigerator of embodiment 1. In fig. 1, the left side is the front side of the refrigerator, and the right side is the rear side of the refrigerator. In addition, fig. 2 is a block diagram showing a control system of the refrigerator. The X-Y-Z orthogonal coordinate system shown in the drawings is used for easy understanding of the embodiments of the present invention, and is not limited to 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 up-down direction (height direction).

As shown in fig. 1, the refrigerator 10 has a main body 12. The main body 12 includes: an outer case 14 made of a metal material to constitute an outer surface of the refrigerator 10; an inner case 16 made of a resin material such as ABS and constituting an inner surface of the refrigerator 10; and a heat insulating material (heat insulating material) 18 such as hard foamed polyurethane filled in the space between the outer case 14 and the inner case 16.

The main body 12 of the refrigerator 10 has a plurality of storage chambers for storing foods (food, processed food of food, etc.). In the case of the present embodiment, as the storage chamber, there are a refrigerating chamber 12a, a freezing/thawing chamber 12b, a freezing chamber 12c, and a vegetable chamber 12d from the uppermost side. Further, in the case of the present embodiment, the freezing/thawing chamber 12b and the freezing chamber 12c communicate with each other.

The refrigerating chamber 12a is a space maintained in a temperature zone (temperature zone) where food is not frozen, for example, in a temperature zone of 1 to 5 ℃. In addition, the freezing/thawing chamber 12b and the freezing chamber 12c are spaces maintained at a temperature band where food is frozen, for example, a temperature band of-22 ℃ to-15 ℃. The freezing/thawing chamber 12b can heat not only frozen foods but also foods in a frozen state, for example, thawing frozen foods, which will be described in detail later. The vegetable room 12d is a space in which a temperature range, for example, a temperature range of 2 to 7 ℃ is maintained equal to or higher than the temperature range of the refrigerator room 12 a. In addition, the refrigerator 10 may have a slight freezing space of-1 deg.c and-3 deg.c in addition to these spaces.

In the case of the present embodiment, a machine chamber 12e is provided at an upper portion of the main body 12 of the refrigerator 10. The machine chamber 8 houses a compressor 20 and the like that constitute a refrigeration cycle of the refrigerator 10 and circulate a refrigerant of the refrigeration cycle. Alternatively, the machine room 12e may be provided at the lower portion of the main body 12 of the refrigerator 10.

In the case of the present embodiment, a cooling chamber 12f is provided on the back surface side of the freezing chamber 12c and the vegetable chamber 12 d. A cooler 22 through which a refrigerant passes and which constitutes a refrigeration cycle of the refrigerator 10 is disposed in the cooling chamber 12f. In addition, a cooling fan 24 is provided in the cooling chamber 12f, which blows air (cool air) of the cooling chamber 12f cooled by the cooler 22 to the refrigerating chamber 12a, the freezing/thawing chamber 12b, the freezing chamber 12c, and the vegetable chamber 12 d.

In the case of the present embodiment, 3 doors 12g to 12i are provided in the refrigerator 10. The door 12g can be opened and closed to communicate or shut off the refrigerator compartment 12a from the outside. The door 12h can be opened and closed to communicate or shut the freezing/thawing chamber 12b and the freezing chamber 12c from the outside. The door 12i can be opened and closed to communicate or shut off the vegetable room 12d from the outside.

As shown in fig. 2, dampers 26A to 26C (only damper 26B is shown in fig. 1) for controlling the flow rate of the cooling air flowing into each of the chambers 12a to 12d are disposed in the flow path between each of the chambers 12a to 12d and the cooling fan 24. The damper 26B is disposed in the flow path between the freezing/thawing chamber 12B and the cooling fan 24. The cool air flows into the freezing chamber 12c through the freezing/thawing chamber 12 b.

Further, as shown in fig. 2, the refrigerator 10 has temperature sensors 28A to 28C that measure the internal temperatures of the respective refrigerating chamber 12a, freezing/thawing chamber 12b, freezing chamber 12C, and vegetable chamber 12 d.

As shown in fig. 2, the control unit 30 of the refrigerator 10 performs cooling control based on the measurement results of the plurality of temperature sensors 28A to 28C, that is, by performing output control of the compressor 20, rotation speed control of the cooling fan 24, and opening and closing control of the dampers 26A to 26C, it is possible to appropriately maintain the temperatures in the refrigerating compartment 12a, the freezing/thawing compartment 12b, the freezing compartment 12C, and the vegetable compartment 12 d. The control unit 30 is, for example, a control circuit board disposed in the machine room 12e, and includes a processor such as a CPU, a memory such as a memory storing a program, and a circuit. The compressor 20, the cooling fan 24, and the dampers 26A to 26C are controlled by the processor according to a program stored in the storage device.

As shown in fig. 1, the refrigerator 10 includes door opening/closing sensors 32A to 32C for detecting the opening/closing states of the plurality of doors 12g to 12i, respectively. The door opening/closing sensors 32A to 32C are, for example, switches that detect the doors 12g to 12i in the closed state by coming into contact with the doors 12g to 12i. The door opening/closing sensors 32A to 32C are provided at positions on the main body 12 of the refrigerator 10 that can be brought into contact with the inner surfaces of the doors 12g to 12i. The detection signals of the door opening/closing sensors 32A to 32C are sent to the control unit 30. The control unit 30 controls ON/OFF of lighting devices (not shown) provided in the refrigerator compartment 12A, the freezer compartment 12b, the freezer compartment 12C, and the vegetable compartment 12d, respectively, based ON detection signals from the door opening/closing sensors 32A to 32C, for example. The switch may be a mechanical switch or a non-contact switch, which is a magnetic sensor such as a hall sensor. The magnetic sensor such as the hall sensor, the MR sensor, the reed switch, etc. is easily miniaturized as compared with the mechanical switch, and has an advantage of not impairing the design of the refrigerator 10 because there is no protrusion.

As shown in fig. 2, in the case of the present embodiment, the refrigerator 10 has a user interface (user interface) 34 for a user to operate the refrigerator 10. The user interface 34 may be a touch panel or the like assembled in the refrigerator 10, and/or may also be a portable terminal of a user. In the case where the user interface 34 is a portable terminal, software (application) for operating the refrigerator 10 is installed on the portable terminal.

The user interface 34 notifies the user that the corresponding door 12g to 12i is in an open state when any one of the door opening/closing sensors 32A to 32C detects that the door is open for a predetermined time, for example. In addition, the user interface 34 is provided for use by a user when thawing is to be performed using the freeze/thaw chamber 12 b. Details of the freezing/thawing chamber 12b will be described below.

Fig. 3 is a perspective view of a heating assembly. In addition, fig. 4 is a sectional view of the heating assembly, and fig. 5 is a sectional view of the heating assembly taken along the line A-A shown in fig. 4. Further, fig. 6 is a block diagram showing a control system of the heating assembly.

In the case of the present embodiment, a heating unit (heating module) 40 shown in fig. 3 to 5 is a unit (module) for heating frozen foods, and is incorporated in the refrigerator 10. The freezing/thawing chamber 12b is disposed within the heating assembly 40. The heating unit 40 is configured to generate an alternating electric field in the freezing/thawing chamber 12b, and to dielectrically heat the food product by the alternating electric field, which will be described in detail later.

As shown in fig. 3 to 5, the heating element 40 has a rectangular parallelepiped shape, and is a double-wall structure having an inner case 42 and a shield case 44 that houses the inner case 42. The shield case 44 functions as a housing of the heating assembly 40. The inner case 42 divides (defines) a housing chamber for housing food products, i.e., a freezing/thawing chamber 12b.

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

In the case of the present embodiment, as shown in fig. 3, the heating unit 40 has a drawer 46 for accommodating food, which can be put into the freezing/thawing chamber 12b in the front-rear direction (X-axis direction) and taken out from the freezing/thawing chamber 12 b. The drawer 46 is made of a resin material. As shown in fig. 5, a guide rail 47 for guiding the drawer 46 in the front-rear direction (X-axis direction) when the drawer 46 is taken in and out is provided on the inner wall surface 42a of the inner case 42. With such a drawer 46, it is easy to take and put food from the freezing/thawing chamber 12 b.

In addition, in order to be able to freeze the food product within the freezing/thawing chamber 12b, the inner housing 42 and the shield housing 44 of the heating assembly 40 have a plurality of vent holes 42b, 44a communicating with the freezing/thawing chamber 12 b. The cool air having passed through the damper 26B flows into the freezing/thawing chamber 12B through the ventilation holes 42B, 44a. Thereby, the food in the heating unit 40, that is, the freezing/thawing chamber 12b can be frozen.

For dielectric heating of the food product in the freezing/thawing chamber 12b, for example for thawing the food product in a frozen state, the heating assembly 40 has a first electrode 48 and a second electrode 50.

As shown in fig. 4 and 5, the first electrode 48 and the second electrode 50 are flat plate-like members made of a metal material. The first electrode 48 and the second electrode 50 are disposed in the shield case 44 so as to face (face) each other with a gap therebetween. In the case of the present embodiment, the first electrode 48 and the second electrode 50 are opposed to each other in the up-down direction (Z-axis direction) and are parallel to each other. The first electrode 48 and the second electrode 50 facing each other with a gap therebetween form a heating space HZ for dielectric heating of the food. The drawer 46 is provided to the heating unit 40 so as to be able to be inserted into and taken out from 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 disposed between the top plate portion 42c of the inner case 42 and the top plate portion 44b of the shield case 44. A space (i.e., an air layer) is provided between the shield case 44 and the first electrode 48.

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

In order to form a heating space HZ between the first electrode 48 and the second electrode 50, as shown in fig. 6, the refrigerator 10 has an oscillating portion 52 that generates an alternating voltage applied between the first electrode 48 and the second electrode 50. The oscillating portion 52 is, for example, an oscillating circuit board disposed in the machine chamber 12e of the refrigerator 10, and is electrically connected to the first electrode 48 and the second electrode 50. The oscillating portion 52 converts an ac voltage from a power supply portion 54 of the refrigerator 10 connected to a commercial power (commercial power supply), and applies the converted ac voltage between the first electrode 48 and the second electrode 50. An ac voltage having a predetermined VHF band frequency, for example, 40.68MHz, is applied between the first electrode 48 and the second electrode 50.

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

In the case of the present embodiment, as shown in fig. 6, the refrigerator 10 has a matching circuit 56 for matching the impedance between the first electrode 48 and the second electrode 50. The matching circuit 56 is, for example, a circuit board housed in the heating element 40. The matching circuit 56 is electrically connected to the first electrode 48 and the second electrode 50. In the case of the present embodiment, the second electrode 50 is grounded.

The operation of the matching circuit 56 will be described. When thawing of a food in a frozen state is advanced, water molecules in the food are increased. When the water molecules increase, the impedance between the first electrode 48 and the second electrode 50 changes from a proper value, and the reflectance increases. Here, the reflectance is a ratio of the reflected wave returned to the oscillation section 52 to the incident wave output from the oscillation section 52. If the reflectivity increases, the efficiency of dielectric heating of the food product decreases. The 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, in order to maintain the impedance between the first electrode 48 and the second electrode 50 at an appropriate value by the matching circuit 56, the refrigerator 10 has a reflected wave detecting circuit 58. The reflected wave detection circuit 58 is provided on, for example, a circuit board disposed in the machine room 12e of the refrigerator 10. The control unit 30 calculates the reflectance based on the incident wave output from the oscillation unit 52 and the reflected wave detected by the reflected wave detection circuit 58. The control unit 30 controls the matching circuit 56 so that the impedance between the first electrode 48 and the second electrode 50 becomes a proper value (i.e., proper value) based on the calculated reflectance.

When the user places the food to be heated in the heating space HZ of the freezing/thawing chamber 12b and gives a heating instruction to the user interface 34, the control unit 30 outputs a heating start signal for generating an ac voltage to the oscillating unit 52, and causes the oscillating unit 52 to generate an ac voltage. Thus, an alternating voltage is applied between the first electrode 48 and the second electrode 50, and an alternating electric field is generated in the shield case 44 (the freezing/thawing chamber 12 b), and the food is dielectrically heated by the alternating electric field.

During heating of the food product in the heating space HZ, an alternating electric field is generated within the freezing/thawing chamber 12 b. 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 (the freezing/thawing chamber 12 b). In order to suppress leakage of the alternating electric field through the opening 44c on the front side of the shield case 44, as shown in fig. 1, a metal shield plate 12j covering the opening 44c of the shield case 44 is provided on the door 12h.

In addition, in the case where the gate 12h is not completely closed, and therefore the alternating electric field can leak to the outside, the application of the alternating voltage between the first electrode 48 and the second electrode 50 through the oscillating portion 52 is prohibited. That is, the oscillating portion 52 can generate the alternating voltage only when the door opening/closing sensor 32B is detecting the door 12h in the closed state. In the case of the present embodiment, when receiving a defrosting instruction from the user via the user interface 34, the control unit 30 outputs a heating start signal to the oscillation unit 52 if the door opening/closing sensor 32B is detecting the closed state of the door 12h. On the other hand, when the defrosting instruction by the user is received, if the door opening/closing sensor 32B does not detect the door 12h in the closed state, the control unit 30 does not output the heating start signal to the oscillating unit 52, and notifies the user to close the door 12h via the user interface 34.

Further, in the case of the present embodiment, while the oscillating unit 52 is generating the ac voltage (i.e., while the food is being dielectrically heated), if the door 12h is opened, that is, the door opening/closing sensor 32B can no longer detect the door 12h in the closed state, the oscillating unit 52 generating the ac voltage stops the generation of the ac voltage. In the case of the present embodiment, the control unit 30 outputs a heating stop signal to the oscillation unit 52, and thereby the oscillation unit 52 stops generating the ac voltage.

By such ac voltage generation control of the oscillating portion 52 based on the open/close state of the door 12h, leakage of the alternating electric field to the outside of the shield case 44 (the freezing/thawing chamber 12 b) can be suppressed. In the case of the present embodiment, the door opening/closing sensor 32B is a switch that detects the door 12h in the closed state by being in contact with the door 12h and is located outside the shield case 44, and is therefore not susceptible to the alternating electric field generated in the shield case 44. As a result, leakage of the alternating electric field to the outside of the shield case 44 can be reliably suppressed.

In addition, in the case of the present embodiment, as shown in fig. 4, the heating assembly 40 further has a drawer detection sensor 60 that detects the drawer 46. Specifically, when the drawer 46 is positioned at a predetermined position between the first electrode 48 and the second electrode 50, the drawer detection sensor 60 can detect the drawer 46. The "predetermined position" as used herein refers to a 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. For this purpose, as shown in fig. 3, a mark 46b for presenting the placement position of the food to be heated to the user is provided on the bottom surface 46a of the drawer 46. That is, when the food to be heated is placed on the mark 46b and the drawer 46 is disposed at a predetermined position, the food to be heated is disposed in the heating space HZ between the first electrode 48 and the second electrode 50, and can be appropriately dielectrically heated.

In the case of the present embodiment, as shown in fig. 3 and 4, the drawer detection sensor 60 is a mechanical sensor that is provided at the opening edge 42e of the inner case 42 and can be brought into contact with the front end 46c of the drawer 46. As a result, the drawer detection sensor 60 is provided outside the freezing/thawing chamber 12b, that is, outside the shield case 44. Thus, the drawer detection sensor 60 can reliably detect the drawer 46.

In contrast, if the drawer detection sensor 60 is provided inside the freezing/thawing chamber 12b, that is, the shield case 44 that generates the alternating electric field, there is a possibility that the drawer detection sensor 60 may erroneously detect the drawer 46. For example, in the case where the drawer sensor 60 is a hall sensor that detects a magnetic field, there is a possibility that malfunction occurs due to an alternating electric field (magnetic field) generated inside the shield case 44. In addition, for example, in the case where the drawer sensor 60 is a mechanical sensor, there is a possibility that the contact surface of the drawer detection sensor 60 and the contact surface of the drawer 46 adhere to each other via ice. In addition, the movable member of the drawer detection sensor 60 may not be moved properly due to freezing. Accordingly, the drawer detection sensor 60 is disposed outside the electric wave irradiation space of the freezing/thawing chamber 12b, that is, outside the space between the first electrode 48 and the second electrode 50.

In the case of the present embodiment, the oscillating unit 52 can generate an ac voltage only when the drawer 46 located at the predetermined position is being detected by the drawer detection sensor 60. In the case of the present embodiment, the drawer detection sensor 60 is electrically connected to the oscillating portion 52. The oscillation unit 52 stands by in a state where an ac voltage can be generated while receiving a detection signal indicating that the drawer 46 is located at a predetermined position from the drawer detection sensor 60. Then, when receiving the heating start signal from the control unit 30, the oscillation unit 52 in the standby state starts generating the ac voltage. On the other hand, during a period when the detection signal is not received from the drawer detection sensor 60, the oscillating unit 52 does not generate an ac voltage even when the heating start signal is received from the control unit 30.

Accordingly, in the present embodiment, when the door opening/closing sensor 32B detects the door 12h in the closed state and the drawer detection sensor 60 detects the drawer 46 positioned at the predetermined position, the oscillating portion 32 generates the ac voltage applied between the first electrode 48 and the second electrode 50. Thus, even when the drawer 46 is not positioned at the predetermined position in the state where the door 12h is closed, the heating target food is not properly arranged in the heating space HZ between the first electrode 48 and the second electrode 50, and the start of dielectric heating can be suppressed. As a result, insufficient thawing of the food can be suppressed, and wasteful power consumption can be suppressed.

When the drawer 46 is pulled out from the predetermined position during the period in which the ac voltage is generated by the oscillating portion 52 (i.e., during the dielectric heating of the food), that is, when the drawer 46 located at the predetermined position is no longer detected by the drawer detection sensor 60, the oscillating portion 52 that is generating the ac voltage stops generating the ac voltage. In the case of the present embodiment, when the detection signal from the drawer detection sensor 60 can no longer be received, the oscillating portion 52 stops generating the ac voltage.

In the case of the present embodiment, in order to pull the drawer 46 out of the predetermined position while the ac voltage is generated in the oscillating portion 52 (that is, while the food is being dielectrically heated), the door 12h needs to be opened first. Accordingly, at the time of opening the door 12h, the door opening/closing sensor 32B cannot detect the door 12h in the closed state, and the oscillating portion 52 stops generating the ac voltage.

However, there are cases where: although the door 12h is opened, the oscillating portion 52 generates an ac voltage due to some reason, for example, due to erroneous detection of the door opening/closing sensor 32B or the like. In this case, when the drawer 46 is pulled out from the prescribed position, so that the drawer detection sensor 60 can no longer detect the drawer 46 located at the prescribed position, the oscillating portion 52 stops generating the alternating voltage.

Further, 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 is capable of detecting (touching) the front end 46c of the drawer 46. The drawer detection sensor 60 may be provided at a position other than the opening edge 42e of the inner case 42. That is, the drawer detection sensor 60 may be positioned at a position where the drawer 46 disposed at a predetermined position can be detected. However, the drawer detection sensor 60 is preferably arranged at such a position: in this position, wiring such as the drawer detection sensor 60 itself and signal lines extending from the sensor is not greatly affected by the alternating electric field generated in the shield case 44. This can suppress malfunction of the drawer detection sensor 60 due to the alternating electric field.

As to the influence of the alternating electric field, as shown in fig. 1, the door opening and closing sensor 32B, the control section 30, and the oscillating section 52 are located outside the shield case 44 of the heating assembly 40 that generates the alternating electric field, and are therefore less susceptible to the alternating electric field generated inside the shield case 44. This can suppress malfunction of the door opening/closing sensor 32B, the control unit 30, and the oscillating unit 52 due to the alternating electric field.

Further, although the door 12h is opened and the drawer 46 is not located at a predetermined position, there is a possibility that the oscillating portion 52 generates an ac voltage due to some reason. In order to suppress leakage of the alternating electric field to the outside of the shield case 44 (the freezing/heating chamber 12 b) caused thereby, the positions of the first electrode 48 and the second electrode 50 within the shield case 44 are specified. 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. The distance D1 will be specifically described.

Fig. 7A is a diagram showing simulation results of expansion of an alternating electric field in the front-rear direction. Fig. 7B is a diagram showing simulation results of the expansion of the alternating electric field in the left-right direction.

As shown in fig. 7A, an alternating electric field generated by an alternating voltage applied between the first electrode 48 and the second electrode 50 expands in the front-rear direction (X-axis direction) within the shield case 44. In addition, as shown in fig. 7B, an alternating electric field generated by an alternating voltage applied between the first electrode 48 and the second electrode 50 expands in the left-right direction (Y-axis direction) within the shield case 44.

The electric field strength E [ V/mm ] of the alternating electric field generated between the first electrode 48 and the second electrode 50 is expressed by the expression 1, and can be expressed in a simplified manner by the voltage V between the first electrode 48 and the second electrode 50 and the distance D [ mm ] in the opposite direction (Z-axis direction) between the first electrode 48 and the second electrode 50.

The voltage V can be expressed by the output W [ W ] and the impedance zΩ of the oscillation section 52 as shown in expression 2. 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 oscillation section 52 with the impedance Z adjusted by the matching circuit 56, reflection of the electric wave can be suppressed. For example, the impedance Z is typically 50Ω.

Thus, the electric field strength E can be expressed as in equation 3.

As a conditional expression capable of suppressing leakage of the alternating electric field generated by application of the alternating voltage between the first electrode 48 and the second electrode 50 to the outside of the shield case 44 through the opening 44c, the inventors found that expression 4 through experiments.

The 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 oscillating portion 52 so as to satisfy the equation 4. By the distance D1 thus determined, leakage of the alternating electric field to the outside of the shield case 44, that is, the outside of the freezing/heating chamber 12b can be suppressed.

For example, when the impedance Z (output impedance of the oscillating portion 52) is 50Ω, the output power W is 100W, and the inter-electrode distance D is 100mm, if D1 is greater than 17.67mm, leakage of the alternating electric field to the outside of the shield case 44, that is, to the outside of the freezer/heating chamber 12b can be suppressed.

Further, as shown in fig. 4 and 7A, a relatively high-intensity electric field is generated near the end of the shield case 44 on the side close to the opening 44c, that is, the front end 48a of the first electrode 48. This is because the first electrode 48 is an ungrounded electrode, unlike the second electrode 50. In order that such a relatively high-intensity electric field does not leak to the outside of the shield case 44 through the opening 44c of the shield case 44, as shown in fig. 4, the front end 48a of the first electrode 48 is farther from the opening 44c of the shield case 44 than the front end 50a of the second electrode 50.

In the case of the present embodiment, as shown in fig. 5, the distance D2 from the side end 50b of the second electrode 50 in the left-right direction (Y-axis direction) to the inner wall surface 44D of the shield case 44 is also defined in the same manner as the distance D1. The distance D2 is determined so as to satisfy equation 5 based on the output power W and the output impedance Z of the oscillating unit 52, as in the distance D1.

Equation 4 and equation 5 for determining the distance D1 and the distance D2 are the same. However, the expression 5 is not a conditional expression for suppressing leakage of the alternating electric field to the outside of the shield case 44, unlike the expression 4. Equation 5 is a conditional expression for suppressing formation of capacitance between the side end 50b of the second electrode 50 and the inner wall surface 44d of the shield case 44. When the distance D2 does not satisfy the 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 can reach the inner wall surface 44d of the shield case 44. As a result, the electric wave leaks through the shield case 44, and a part of the output power of the oscillating portion 52 is wasted, and an alternating electric field for dielectric heating of the food cannot be generated. The efficiency of dielectric heating of the food product is then reduced. In order to suppress such leakage of radio waves and reduction in efficiency of dielectric heating, the distance D2 is determined to satisfy equation 5.

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

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

The present invention has been described above by referring to the above embodiments, but the present invention is not limited to the above embodiments.

For example, as shown in fig. 1, in the case of the above embodiment, the door 12h is not coupled to the drawer 46. Embodiments of the present invention are not limited thereto.

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

As shown in fig. 8, in the refrigerator 110 of another embodiment, a door 112h that communicates or blocks the heating space HZ with the outside of the shield case 44 is coupled to a drawer 46 that can be placed in and removed from the heating space HZ. Thus, when the door 112h is opened, 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 up-down direction (Z-axis direction), but a door that can move in parallel in the front-back direction (X-axis direction). In addition, in the case of this embodiment, the drawer detection sensor is omitted. Instead, the door open/close sensor 32B not only performs open/close detection of the door 112h, but also functions as a drawer detection sensor.

In the case of the above embodiment, as shown in fig. 5, the heating space HZ for thawing the food is a part of the freezing/thawing chamber 12b for freezing the food. Embodiments of the present invention are not limited thereto. Alternatively, the entire freezing/thawing chamber 12b may be a heating space HZ.

In the case of the above embodiment, as shown in fig. 4 and 5, the first electrode 48 and the second electrode 50 face each other in the up-down direction (Z-axis direction). The second electrode 50 located on the lower side is grounded as shown in fig. 6. However, the present embodiment is not limited thereto. For example, the first electrode and the second electrode may be vertically opposed to each other, and the upper first electrode may be grounded. For example, the first electrode and the second electrode may be opposed to each other in the left-right direction (the width direction of the refrigerator).

Also, in the case of the above-described embodiment, the freezing/thawing chamber 12b is provided inside the heating unit 40. That is, the heating unit 40 is configured to be capable of dielectric heating of the food, and also capable of freezing and preserving the food. Embodiments of the present invention are not limited thereto. The heating assembly 40 may also be used for dielectric heating of food only. In this case, it is not necessary to introduce cold air into the heating module 40.

That is, in broad terms, a refrigerator of an embodiment of the present invention includes: a shield shell made of a metal material having an opening portion on a front side communicating an inside and an outside; a flat plate-shaped first electrode disposed in the shield case; a flat-plate-shaped second electrode disposed in the shield case so as to face the first electrode with a gap therebetween, the second electrode being grounded, and a heating space for dielectric heating of the food being formed between the second electrode and the first electrode; and an oscillating portion that can generate an alternating voltage applied between the first electrode and the second electrode, a relative directional distance D of the first electrode and the second electrode, an output power W of the oscillating portion, an output impedance Z of the oscillating portion, and a distance D1 from a front end of the second electrode to the opening portion of the shield case satisfy the following mathematical expression:

industrial applicability

The present invention is applicable to a refrigerator capable of dielectric heating of food.

Claims (5)

1. A refrigerator, comprising:

a shield shell made of a metal material having an opening portion on a front side communicating an inside and an outside;

a flat plate-shaped first electrode disposed in the shield case;

A flat-plate-shaped second electrode disposed in the shield case so as to face the first electrode with a gap therebetween, the second electrode being grounded, and a heating space for dielectric heating of the food being formed between the second electrode and the first electrode; and

An oscillating portion for generating an alternating voltage applied between the first electrode and the second electrode,

The relative direction distance D of the first electrode and the second electrode, the output power W of the oscillating portion, the output impedance Z of the oscillating portion, and the distance D1 from the front end of the second electrode to the opening portion of the shield case satisfy the following mathematical expression:

2. the refrigerator of claim 1, wherein:

The front end of the first electrode is farther from the opening of the shield case than the front end of the second electrode.

3. The refrigerator according to claim 1 or 2, wherein:

The relative 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 satisfy the following mathematical expression:

4. The refrigerator of claim 3, wherein:

The side end of the first electrode is farther from the inner wall surface of the shield case than the side end of the second electrode.

5. The refrigerator according to any one of claims 1 to 4, wherein:

the heating space is at least a portion of a freezer compartment that freezes the food product.