JP2023161106A - refrigerator - Google Patents

Abstract

To provide a refrigerator that comprises a storage chamber capable of freezing, storing, and thawing a stored object in a desired state, and is highly reliable.SOLUTION: A refrigerator comprises: a coaxial cable 56 directly or indirectly connecting an oscillation circuit 22 for forming high-frequency power, and a matching circuit 23 for matching load impedance and output impedance of the oscillation circuit 22; and noise suppressing means for preventing leakage of noise from the coaxial cable 56. The refrigerator can restrain a malfunction caused by noise and leakage of radio waves to the outside, is compact and highly reliable, and has cooling and storage functions.SELECTED DRAWING: Figure 19A

Description

The present disclosure relates to a refrigerator that has a storage chamber that has both a freezing function and a function of thawing frozen products.

Patent Document 1 shows a refrigerator having a storage chamber capable of defrosting conventional frozen products. This refrigerator is provided with a high-frequency heating chamber (storage chamber) capable of thawing frozen products as well as a freezing chamber inside a freezer main body having a freezing device and a magnetron for high-frequency generation, and a cold air circulation duct is connected to the high-frequency heating chamber. The system is configured to thaw frozen products by supplying cold air from the refrigeration system and irradiating high frequency waves from the magnetron.

Japanese Patent Application Publication No. 2002-147919

The present disclosure provides a refrigerator that can freeze, store, and thaw preserved items stored in the thawable storage chamber in a desired state, thereby improving storage performance.

at least one storage room having a space capable of storing preserved items;
an oscillator that generates high-frequency power;
a first electrode that receives high frequency power generated from the oscillator and generates an electric field in the storage space, and a second electrode;
a load impedance formed by the first electrode, the second electrode, and the stored object stored in the storage chamber; and a matching part that matches the output impedance of the oscillation part.
high frequency wiring that directly or indirectly connects the oscillation section and the matching section;
The apparatus is equipped with a noise suppressing means for preventing noise leakage from the high frequency wiring.

The refrigerator according to the present disclosure is capable of freezing, storing, and thawing stored items stored in the storage chamber in a desired state using a high-frequency electric field formed between the first electrode and the second electrode. We offer small and reliable refrigerators.

Vertical cross-sectional view of the refrigerator of Embodiment 1 Front sectional view showing the freezing/thawing chamber in the refrigerator of Embodiment 1 Side sectional view showing the freezing/thawing chamber in the refrigerator of Embodiment 1 Vertical cross-sectional view when incorporating the freezing/thawing chamber in the refrigerator of Embodiment 1 Front sectional view showing a modification of the freezing/thawing chamber in the refrigerator of Embodiment 1 Side sectional view showing a modification of the freezing/thawing chamber in the refrigerator of Embodiment 1 Vertical cross-sectional view when incorporating the freezing/thawing chamber in the refrigerator of Embodiment 1 A diagram showing the electrode holding area on the back side of the freezing/thawing chamber in Embodiment 1. A block diagram showing the configuration of a dielectric heating mechanism provided in the refrigerator of Embodiment 1. Schematic circuit diagram of AC/DC converter that drives various circuits A plan view of the first electrode and second electrode on the top side of the freezing/thawing chamber in the refrigerator of Embodiment 1, viewed from above. A diagram showing the relationship between the electrode spacing between the first electrode and the second electrode and the electric field strength between both electrodes. Electric field simulation diagram showing the results of simulation for dielectric heating configuration An electric field simulation diagram showing the results of simulation for the dielectric heating configuration of the freezing/defrosting chamber in the refrigerator of Embodiment 1. In the configuration of Embodiment 1, a diagram showing the waveforms of the control signals of the oscillation circuit and damper in the electric field generation process, and also showing the food temperature, the room temperature of the freezing/thawing chamber, and the humidity of the freezing/thawing chamber at that time. Flowchart showing control after electric field generation processing is completed in the freezing/thawing chamber in the configuration of Embodiment 1 Waveform diagram showing cooling operation during frozen storage in a conventional refrigerator Waveform diagram showing cooling operation performed in the freezing/thawing chamber of the refrigerator of Embodiment 1 Waveform diagram showing the state of each element during rapid cooling operation in the configuration of Embodiment 1 A diagram showing an example of a high frequency cutoff circuit when the refrigerator door of Embodiment 1 is opened. A diagram showing another example of the high frequency cutoff circuit when the refrigerator door of Embodiment 1 is opened. A diagram showing still another example of the high frequency cutoff circuit when the refrigerator door of Embodiment 1 is opened. A sectional view showing an example of cable wiring to the freezing/thawing chamber in the refrigerator of Embodiment 1. A sectional view showing an example of cable wiring to the freezing/thawing chamber in the refrigerator of Embodiment 1.

(Findings, etc. that formed the basis of this disclosure)
At the time the inventors came up with the present disclosure, the refrigerator described in Patent Document 1 was known.

However, the refrigerator described in Patent Document 1 is configured to irradiate high frequency waves from a magnetron via an antenna etc. to the frozen products in the high frequency heating chamber to perform high frequency heating. It was difficult to thaw it into the desired state by heating. In addition, since the frozen product is configured to be heated by irradiating high frequency waves from a magnetron, it is necessary to install a relatively large magnetron and its cooling mechanism, making it difficult to miniaturize the product. There was a problem.

Furthermore, since the device uses high frequencies, it generates normal mode noise or common mode noise, which is difficult to suppress.

In view of these problems, the inventors have come to form the subject matter of the present disclosure in order to solve these problems.

Therefore, the present disclosure provides a compact and highly reliable refrigerator that can freeze, store, and thaw stored items stored in a storage chamber in a desired state.

EMBODIMENT OF THE INVENTION Hereinafter, as an embodiment of the refrigerator of the present invention, a refrigerator equipped with a freezing function will be described with reference to the accompanying drawings. Note that the refrigerator of the present disclosure is not limited to the configuration of the refrigerator described in the embodiments below, and can also be applied to a freezer having only a freezing function, and the configuration described in the embodiments below is applicable to the refrigerator of the present disclosure. It includes various types of refrigerators and freezers with different characteristics. Therefore, in the present invention, a refrigerator has a configuration including a refrigerator compartment and/or a freezing compartment.

Furthermore, the numerical values, shapes, configurations, steps, order of steps, etc. shown in the following embodiments are merely examples, and do not limit the present invention. Among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the most significant concept will be described as arbitrary constituent elements. In addition, in the embodiment, the same elements may be given the same reference numerals even in the modified examples, and the description thereof may be omitted. Further, the drawings mainly schematically show each component for ease of understanding.
(Embodiment 1)
Embodiment 1 of the present disclosure will be described below with reference to the drawings. Note that in explaining the present disclosure, each item will be explained separately for easy understanding.

[1-1. Overall configuration of refrigerator]
FIG. 1 is a diagram showing a longitudinal section of a refrigerator 1 according to the first embodiment.

In FIG. 1, the left side is the front side of the refrigerator 1, and the right side is the back side of the refrigerator 1. The refrigerator 1 includes an outer box 3 mainly made of a steel plate, an inner box 4 made of resin such as ABS, and a foamed heat insulating material (e.g. , hard urethane foam) 40.

The heat insulating box body 2 of the refrigerator 1 includes a plurality of storage chambers, and an openable/closable door is provided at the front opening of each storage chamber. Each storage room is sealed to prevent cold air from leaking by closing the door. In the refrigerator 1 of the first embodiment, the uppermost storage compartment is the refrigerator compartment 5. Two storage compartments, an ice-making compartment 7 and a freezing/thawing compartment 6, are arranged in parallel on both sides directly below the refrigerator compartment 5. Further, a freezing compartment 8 is provided directly below the ice making compartment 7 and the freezing/thawing compartment 6, and a vegetable compartment 9 is provided at the bottom immediately below the freezing compartment 8. Although each storage compartment in the refrigerator 1 of the first embodiment has the above-mentioned configuration, this configuration is only an example, and the arrangement of each storage compartment can be changed as appropriate at the time of design according to specifications and the like.

The refrigerator compartment 5 is maintained at a temperature that does not freeze, such as a temperature range of 1° C. to 5° C., in order to refrigerate food and other preserved items. The vegetable compartment 9 is maintained at a temperature similar to or slightly higher than that of the refrigerator compartment 5, for example, 2°C to 7°C. The freezer compartment 8 is set in a freezing temperature range for frozen storage, for example, a temperature range of -22°C to -15°C. The freezing/thawing chamber 6 is normally maintained in the same freezing temperature range as the freezing chamber 8, and in response to a user's electric field generation command, an electric field generation process is performed to thaw stored items (frozen products). be exposed. Details regarding the configuration of the freezing/thawing chamber 6 and the electric field generation process will be described later.

A machine room 10 is provided in the upper part of the refrigerator 1. The machine room 10 houses components constituting the refrigeration cycle, such as a compressor 19 and a dryer that removes moisture from the refrigeration cycle. The location of the machine room 10 is not limited to the upper part of the refrigerator 1, but is appropriately determined depending on the location of the refrigeration cycle, and may be placed in other areas such as the lower part of the refrigerator 1. It may be placed in

A cooling chamber 11 is provided on the back side of the freezer compartment 8 and vegetable compartment 9 in the lower area of the refrigerator 1. The cooling chamber 11 includes a cooler 13 that is a component of a refrigeration cycle that generates cold air, and a cooling fan 14 that blows the cold air generated by the cooler 13 to each storage chamber (3, 4, 5, 6, 7). is provided. The cold air generated by the cooler 13 flows through the air passage 12 connected to each storage compartment by a cooling fan 14, and is supplied to each storage compartment. A damper 12a is provided in the air passage 12 connected to each storage room, and each storage room is maintained within a predetermined temperature range by controlling the rotation speed of the compressor 19 and the cooling fan 14 and controlling the opening and closing of the damper 12a. Ru. A defrosting heater 15 is provided in the lower part of the cooling chamber 11 to defrost frost and ice adhering to the cooler 13 and its surroundings. A drain pan 16, a drain tube 17, and an evaporating dish 18 are provided below the defrosting heater 15, and are configured to evaporate moisture generated during defrosting.

The refrigerator 1 according to the first embodiment is equipped with an operation section 47 (see FIG. 9, which will be described later). A user can issue various commands to the refrigerator 1 using the operation unit 47 (for example, temperature settings for each storage compartment, rapid cooling command, electric field generation command, ice making stop command, etc.). Further, the operation section 47 has a display section that notifies the occurrence of an abnormality. Note that the refrigerator 1 may be configured to include a wireless communication section, connect to a wireless LAN network, and input various commands from a user's external terminal. Furthermore, the refrigerator 1 may be configured to include a voice recognition section so that the user can input voice commands.

2, FIG. 3, and FIG. 5 and FIG. 6 are longitudinal sectional views showing the freezing/thawing chamber 6 in the refrigerator 1 of the first embodiment. The freezing/thawing chamber 6 is a freezer that freezes stored items such as foods stored in the freezing/thawing chamber 6 and maintains them in a freezing temperature range, and also receives an electric field generation command for the stored items in the refrigerator 1. In other cases, it becomes a thawing chamber where electric field generation processing is performed using dielectric heating.

The respective features of FIGS. 2, 3, 5, and 6 will be explained in "System Structure" below.

In the freezing/thawing chamber 6, the cold air generated in the cooler 13 is passed through air channels provided on the back side and the top side of the freezing/thawing chamber 6 so as to maintain the same freezing temperature range as the freezing chamber 8. 12 and is introduced into the freezing/thawing chamber 6 through a plurality of cold air introduction holes 20 provided on the top surface of the freezing/thawing chamber 6. A damper 12a is provided in the air passage 12 leading from the cooling chamber 11 to the freezing/thawing chamber 6, and by controlling the opening and closing of the damper 12a, the freezing/thawing chamber 6 is maintained at a predetermined freezing temperature range, and stored stored items are kept in a predetermined freezing temperature range. is stored frozen.

A cold air exhaust hole (not shown) is formed on the back side of the freezing/thawing chamber 6. The cold air introduced into the freezing/thawing chamber 6 to cool the inside of the freezing/thawing chamber 6 returns to the cooling chamber 11 through a return air passage (not shown) from the cold air exhaust hole, and is recooled by the cooler 13. Ru. That is, the refrigerator 1 according to the first embodiment has a configuration in which cold air generated by the cooler 13 is circulated.

In the freezing/thawing chamber 6, the top surface, back surface, both side surfaces, and bottom surface constituting the inner surface of the storage space are formed of resin inner surface members 32 (32a to 32c) molded from an electrically insulating material. . Further, a door 29 is provided at the front opening of the freezing/thawing chamber 6, and when the door 29 is closed, the storage space of the freezing/thawing chamber 6 is sealed. In the freezing/thawing chamber 6 of the first embodiment, a storage case 31 with an open top is provided on the back side of the door 29, and when the door 29 is opened and closed in the front-back direction, the storage case 31 moves back and forth at the same time. It is configured to do this. By opening and closing the door 29 in the front-back direction, it is possible to easily insert and remove stored items such as food into the storage case 31.

[1-2. Dielectric heating mechanism for generating electric field in storage space]
Next, a dielectric heating mechanism that generates an electric field in the storage space in the freezing/thawing chamber 6 where stored items are placed will be explained.

Note that this dielectric heating mechanism can adjust the heating capacity such as output power. Therefore, if the amount of heating to the stored item exceeds the amount of cooling in the freezing/thawing chamber 6, the stored item is heated. Moreover, when the amount of heating to the preserved object is less than the cooling amount of the freezing/thawing chamber 6, the preserved object is cooled.

FIG. 9 is a block diagram showing the configuration of the dielectric heating mechanism provided in the refrigerator 1 of the first embodiment. The dielectric heating mechanism in the first embodiment includes an oscillation circuit 22 that receives power from a power supply section 48 and forms a predetermined high-frequency signal, a matching circuit 23, a first electrode 24, a second electrode 25, and a control section 50. We are prepared. The oscillation circuit 22 configured using a semiconductor element is miniaturized, and as will be described later, the matching circuit 23 and the electrode holding area 30 (FIGS. 2, 3, and 3), which is a space on the back side of the freezing/thawing chamber 6, are 5, see FIG. 6). The oscillation circuit 22 and the matching circuit 23 serve as a high frequency electric field forming section for forming a high frequency electric field applied between the first electrode 24 and the second electrode 25.

The first electrode 24 is an electrode disposed on the top side of the freezing/thawing chamber 6. The second electrode 25 is an electrode disposed on the bottom side of the freezing/thawing chamber 6. The first electrode 24 and the second electrode 25 are arranged to face each other across the storage space (thawing space) of the freezing/thawing chamber 6, and are arranged on an electrode holding board 52 which will be explained in "Circuit board configuration" below. etc., and the facing interval is set to a predetermined interval (H in FIG. 8). As a result, in the dielectric heating mechanism according to the first embodiment, the first electrode 24 and the second electrode 25 are arranged substantially parallel to each other. In the present invention, "substantially parallel" refers to a state of essentially parallel, but includes errors due to variations in processing accuracy.

The first electrode 24 is provided on one side of the storage space, and the second electrode 25 is provided on the other side of the storage space with the storage space in between. The matching circuit 23 on the back side, the first electrode 24 on the top side, and the second electrode 25 on the bottom side, which make up the dielectric heating mechanism, are covered with an inner surface member 32 to ensure that stored objects do not burn due to contact with them. It can be prevented.

In the configuration of the first embodiment, the first electrode 24 is provided on the top surface of the storage space of the freezing/thawing chamber 6, and the second electrode 25 is provided on the bottom surface of the storage space of the freezing/thawing chamber 6. Although the present invention is not limited to this configuration, it is sufficient that the first electrode 24 and the second electrode 25 face each other with a storage space (thawing space) in between. The same effect can be achieved even when the elements are arranged or arranged so that they face each other in the left and right direction.

The oscillation circuit 22 outputs a high frequency (40.68 MHz in the first embodiment) voltage in the VHF band. When the oscillation circuit 22 outputs a high frequency voltage, an electric field is formed between the first electrode 24 and the second electrode 25 to which the oscillation circuit 22 is connected, and the first electrode 24 and the second electrode 25 of the freezing/thawing chamber 6 are connected to each other. A dielectric storage material placed in the storage space between the electrode 25 is dielectrically heated.

The matching circuit 23 adjusts so that the load impedance formed by the first electrode 24, the second electrode 25, and the stored items stored in the freezing/thawing chamber 6 matches the output impedance of the oscillation circuit 22. be. The matching circuit 23 minimizes reflected waves of the output electromagnetic waves by matching impedances.

The dielectric heating mechanism in the first embodiment includes an incoming reflected wave detection unit that detects an incident wave output from the oscillation circuit 22 to the first electrode 24 and a reflected wave returning from the first electrode 24 toward the oscillation circuit 22. A section 51 is provided. Therefore, the oscillation circuit 22 is electrically connected to the first electrode 24 via the input reflected wave detection section 51 and the matching circuit 23. The control unit 50 calculates the ratio (reflectance) of the reflected wave output to the incident wave output based on the incident wave and the reflected wave detected by the incident reflected wave detection unit 51, and based on the calculation result, as described below. Various controls are carried out. Alternatively, the ratio of reflected wave output to electromagnetic wave output (reflectance ) may be calculated. Furthermore, the various controls described below may be performed using only the reflected wave output, without depending on the electromagnetic wave output setting value or the detected value of the incident wave.

As shown in the control block diagram of FIG. 9, in the dielectric heating mechanism, a control unit 50 controls an oscillation circuit based on signals from an operation unit 47 for performing setting operations by the user, a temperature sensor 49 for detecting temperature inside the refrigerator, etc. 22 and matching circuit 23 are driven and controlled. The control unit 50 is composed of a CPU, and executes a control program stored in a memory such as a ROM to perform various controls.

[1-3. Configuration of circuit board of dielectric heating mechanism]
Since it is desirable that the length of the wiring on the positive electrode side connecting the oscillation circuit 22, the input reflected wave detection unit 51, the matching circuit 23, and the first electrode 24 is short, in this embodiment, the electrode holding circuit including these circuits is short. The substrate 52 (see FIGS. 2, 3, 5, and 6), the first electrode 24, and the second electrode 25 are directly connected without using lead wires or coaxial cables, and are connected to the back side of the freezing/thawing chamber 6. The structure is such that the electrode holding area 30 is disposed in the electrode holding area 30. It is assumed that this electrode holding substrate 52 includes at least the matching circuit 23.

The matching circuit 23 performs impedance matching by adjusting the values of inductance and capacitance. Therefore, heat is generated especially due to loss in the inductor on the matching circuit 23. This heat generation is expressed as waste heat from the matching circuit 23. Devices including the matching circuit 23 and metal parts such as the first electrode 24, the second electrode 25, and the electromagnetic shield 26 (described later) placed around the matching circuit 23 are susceptible to condensation in a freezing temperature environment, and may malfunction due to water droplets or frost formation. However, by configuring the matching substrate 23 to conduct waste heat easily, it is possible to prevent malfunctions. For this reason, it is essential that the electrode holding substrate 52 include at least the matching circuit 23.

Note that the first electrode 24, the second electrode 25, and the electromagnetic wave shield 26 described below generate heat due to a certain amount of electrical loss. Although this heat generation is slight in the first embodiment and does not contribute to preventing dew condensation or frost formation, it is possible to prevent dew condensation or frost formation by intentionally using a material with a large loss.

The dew condensation and frost prevention operation using waste heat is performed when the possibility of dew condensation and frost formation is detected, regardless of whether it is necessary to generate an electric field in the freezing/thawing chamber 6. In other words, the oscillation circuit 22 is operated appropriately to purposely generate waste heat.

In addition, in order to accurately determine whether impedance matching has been sufficiently achieved by the matching circuit 23, an input/reflection wave detection section 51 is configured on the electrode holding substrate 52, and together with the matching circuit 23, it is integrated into one substrate. It is desirable to do so. This eliminates the need for lead wires, coaxial cables, and connectors for connecting these between the matching circuit 23 and the input/reflected wave detection section 51, making it possible to simplify the structure.

In addition, in FIG. 9, the input and reflected wave detection section 51 and the matching circuit 23 are arranged on the electrode holding substrate 52, but the matching circuit 23, the input and reflection wave detection section 51, and the oscillation circuit 22 are all configured. By using a single board, it is also possible to suppress power transmission loss due to lead wires and coaxial cables and improve the accuracy of impedance matching.

Note that each of the above circuits, for example, the oscillation circuit 22 and the matching circuit 23, may be separated and electrically connected using lead wires or coaxial cables. It is also possible to make use of the empty space inside the refrigerator by installing the circuit 22, etc., to achieve a rational arrangement. In this case, in order to perform impedance matching including the coaxial cable, it is desirable to provide the oscillation circuit 22 and the reflected wave detection section 51 on one substrate.

[1-4. Structure of dielectric heating mechanism system]
The dielectric heating mechanism according to the first embodiment configured as described above has a configuration in which the first electrode 24 and the second electrode 25 face each other substantially in parallel, so that the electric field is uniformized in the storage space of the freezing/thawing chamber 6. is planned. In order to dispose the first electrode 24 and the second electrode 25 substantially parallel to each other with a predetermined interval (H in FIG. 8) in this way, the dielectric heating mechanism in the first embodiment is configured as described below. The electrode spacing is maintained at

FIG. 8 is a diagram showing the electrode holding area 30 on the back side of the freezing/thawing chamber 6 in the first embodiment, and shows the electrode holding mechanism in the electrode holding area 30. FIG. 8 is a diagram of the electrode holding area 30 viewed from the back side, in which the first electrode 24 is arranged on the upper side (top side) and the second electrode 25 is arranged on the lower side (bottom side). There is. Positive electrode terminals 24a, 24b, and 24c are provided protruding from the rear end of the first electrode 24. The positive electrode terminals 24a to 24c are bent at right angles and protrude upward (top side) or downward (bottom side) from the rear end of the first electrode 24. Similarly, cathode terminals 25a, 25b, and 25c are provided protruding from the center of the rear end of the second electrode 25. The cathode terminals 25a to 25c are bent at right angles and protrude upward (top side) or downward (bottom side) from the rear end of the second electrode 25.

A first electrode 24 and a second electrode 25 are fixed to the upper and lower parts of the electrode holding substrate 52 , and a matching circuit 23 and an input/reflected wave detection unit 51 are fixed to the electrode holding substrate 52 . The first electrode 24 and the second electrode 25 are securely held. In this way, the electrode holding substrate 52 is configured to substantially securely hold the first electrode 24 and the second electrode 25 with a predetermined interval (H in FIG. 8). In addition, since the electrode holding board 52 includes the matching circuit 23 and the like, its rigidity is increased by the copper foil wiring pattern, and the first electrode 24 and the second electrode 25 are arranged at a predetermined facing interval (see FIG. 8). H), resulting in a structure that can be held in a cantilever manner. Further, the electrode holding substrate 52 may be further provided with the oscillation circuit 22 and the like as described above.

Positive terminals 24a to 24c of the first electrode 24 and cathode terminals 25a to 25c of the second electrode 25 are connected to connection terminals on the positive side and the negative side of the matching circuit 23, respectively. The connections between the positive terminals 24a to 24c and the negative terminals 25a to 25c and each connection terminal of the matching circuit 23 are surface contact connections having a predetermined contact area so as to ensure reliability even when a large current flows. In the first embodiment, the flat terminals are connected to each other by screws in order to ensure reliable surface contact connection. Note that the connection between the terminals may be any connection means that provides a reliable surface contact connection, and is not limited to a screw connection. Furthermore, in order to prevent dew condensation and frost formation using waste heat as described above, a connection between terminals with excellent thermal conductivity is required.

As described above, since the electrode holding substrate 52 is provided as an electrode holding mechanism on the back side of the freezing/thawing chamber 6, the first electrode 24 and the second electrode 25 are configured to face each other substantially in parallel. . In addition, in the configuration of the first embodiment, in order to further ensure that the first electrode 24 and the second electrode 25 face each other substantially in parallel, the first electrode 24, the second electrode 25, the electrode holding substrate 52, and is configured to be incorporated into the freezing/thawing chamber 6 as an integrated high-frequency heating module 53a in a substantially parallel state.

[1-5. Structure of freezing/thawing chamber]
As mentioned above, the insulating box body of the refrigerator 1 includes an outer box 3 made of a steel plate, an inner box 4 made of resin, and a foamed insulation box filled in the space between the outer box 3 and the inner box 4. material (for example, hard urethane foam) 40.

As shown in FIGS. 2 and 3, the freezing/thawing chamber 6 is configured using an inner surface member 32a inside the heat insulating material 40 as an outer frame, and the outside thereof is covered with an electromagnetic shield 26 (26a to 26d). It is being said. This electromagnetic wave shield 26 is provided to surround the freezing/thawing chamber 6 in order to prevent electromagnetic waves from leaking to the outside of the refrigerator 1. Further, the electrode holding area 30 is separated from the freezing/thawing chamber by an inner surface member 32c, and a back side electromagnetic wave shield 26b is also installed on the back side of the inner surface member 32c. The main purpose of the rear electromagnetic wave shield 26b is to prevent the influence of each other's impedance and electric field by dividing the interior of the freezing/thawing chamber 6 and the electrode holding board 52 including the matching circuit 23, etc. .

A flat plate-shaped inner surface member 32b is provided horizontally above the space surrounded by the inner surface member 32a, and the first electrode 24 is mounted on the upper part of the inner surface member 32b. Further, the second electrode 25 is installed on the bottom surface of the inner surface member 32a, and the bottom surface of the inner surface member 32a and the inner surface member 32b are substantially parallel and held at a predetermined interval (H in FIG. 8). Therefore, the first electrode 24 and the second electrode 25 can be maintained in a substantially parallel state by the electrode holding substrate 52 and the inner surface members 32a, 32b, and 32c. The outer box 3 may not be sufficiently parallel to the inside top surface and bottom surface due to foaming variations in the filled and foamed insulation material 40, but with the above-mentioned configuration, it is not affected by foaming and is accurately It will definitely be in a substantially parallel state.

In the manufacturing process, the high frequency heating module 53a is assembled in advance and is inserted into the outer box 3 of the refrigerator 1 as shown in FIG. Furthermore, the refrigerator is completed by inserting a door unit including the door 29, the door-side electromagnetic wave shield 26d, the gasket 36, the storage case 31, etc. into the high-frequency heating module 53a.

Alternatively, configurations such as those shown in FIGS. 5, 6, and 7 may be used. 5, 6, and 7, the outer box 3 of the refrigerator 1, the inner box 4 molded from resin, the insulation material 40 filled and foamed in the space between the outer box 3 and the inner box 4, The structure of the inner surface member 32 (32a to 32c) inside the heat insulating material 40 configured as the outer frame of the thawing chamber 6 and the electromagnetic wave shield 26 outside thereof is the same as in FIGS. 2 and 3.

Above the space surrounded by the inner surface member 32, the first electrode 24 is mounted on the upper part of the flat inner surface member 32b provided in the horizontal direction, and similarly below the space surrounded by the inner surface member 32a. A second electrode 25 is installed on the bottom surface of a flat inner surface member 32c provided horizontally. The front side of the inner surface member 32b and the inner surface member 32c are each fixed by a support 54, and the back side is fixed by the electrode holding substrate 52 and the inner surface member 32c, and the first electrode 24 and the second electrode 25 are held in a substantially parallel state. do.

Since the inner surface member 32b and the inner surface member 32c are held substantially parallel and at a predetermined interval (H in FIG. 8), the first electrode 24 and the second electrode 25 are connected to the electrode holding substrate 52, the support column 54, and the inner surface members 32b, 32c. A substantially parallel state can be maintained by this. The outer box 3 of the refrigerator 1 may not be sufficiently parallel to the top and bottom surfaces of the refrigerator due to uneven foaming of the foamed insulation material 40, but with the above-described configuration, the outer box 3 is not affected by foaming. , accurately and reliably achieve a substantially parallel state.

In this configuration, the high-frequency heating module 53b includes the first electrode 24, the second electrode 25, the inner surface members 32a, 32b, 32c, the support column 54, and the back side electromagnetic wave shield 26b that separates the electrode holding area 30 and the freezing/thawing chamber 6. , an electrode holding substrate 52 including a matching circuit 23 and the like are integrated. In the manufacturing process, the high frequency heating module 53a is assembled in advance and is inserted into the outer box 3 of the refrigerator 1 as shown in FIG. Furthermore, the refrigerator is completed by inserting a door unit including the door 29, the door-side electromagnetic shield 26d, the gasket 36, the storage case 31, etc. into the high-frequency heating module 53b.

In addition, the inner members 32a to 32c are preferably made of a material with a thermal conductivity of 10 W/(m·k) or less of a general industrial ceramic material that is resistant to dew condensation even in a freezer room environment, and in this embodiment, polypropylene, ABS, polycarbonate, etc. It is made of resin material. The electromagnetic wave shield 26 (26a to 26d) is thinner than the inner surface member 32 (32a to 32c) to suppress heat capacity. This can prevent dew condensation on the electromagnetic wave shield 26 and the inner surface member 32 (32a to 32c) in contact with the electromagnetic wave shield 26.

As described above, in the refrigerator 1 of the first embodiment, the dielectric heating mechanism of the freezing/thawing chamber 6 is provided with the electrode holding mechanism on the back side and the front side, or on the side side. The two electrodes 25 can be arranged with a highly accurate facing interval, and can also be reliably arranged substantially parallel with a predetermined interval (H in FIG. 8). As a result, the dielectric heating mechanism of the freezing/thawing chamber 6 prevents the high-frequency electric field from being biased on the electrode surface, makes the high-frequency electric field uniform, and enables uniform electric field generation processing for preserved items (frozen items). This is a possible configuration.
Furthermore, since the refrigerator is completed by inserting a pre-assembled unit as a high-frequency heating module, the manufacturing process is simplified without the need for manufacturing work inside a narrow refrigerator compartment.

[1-6. Electromagnetic shielding mechanism]
As mentioned above, in the freezing/thawing chamber 6, a dielectric material, which is a preserved material, is placed in the atmosphere of the high-frequency electric field between the first electrode 24 and the second electrode 25 and dielectrically heated. Electromagnetic waves are radiated in the thawing chamber 6. In order to prevent this electromagnetic wave from leaking to the outside of the refrigerator 1, the refrigerator 1 of the first embodiment is provided with an electromagnetic wave shielding mechanism surrounding the freezing/thawing chamber 6.

As shown in FIGS. 2 and 3, a top-side electromagnetic wave shield 26a is disposed in a portion of the air passage 12 on the top side of the freezing/thawing chamber 6. The top side electromagnetic wave shield 26a is disposed on the top surface of the heat insulating material 40 that constitutes the bottom side of the refrigerator compartment 5 directly above the freezing/thawing compartment 6, and covers the top side of the freezing/thawing compartment 6. It is arranged. The top-side electromagnetic wave shield 26a has a plurality of openings, and is configured so that its substantial opposing area with respect to the first electrode 24 is small.

The shape of the opening is a slit whose length is from the back side to the front side, so that the magnetic field (current) generated from the positive electrode terminals 24a to 24c toward the front can smoothly flow onto the top side electromagnetic wave shield 26a. We analyzed by electromagnetic wave simulation that the leakage magnetic field that is diffused into the surrounding area is suppressed because the magnetic field passes through the magnetic field.

The top-side electromagnetic wave shield 26a configured in this manner has a configuration in which generation of unnecessary electric fields between it and the first electrode 24 is suppressed. Note that the top-side electromagnetic wave shield 26a may have a mesh structure having a plurality of openings. Further, the top side electromagnetic wave shield 26a may be provided inside the refrigerator compartment 5 located directly above the freezing/thawing compartment 6, but the refrigerator compartment 5 may be provided with a partial compartment or a chilled compartment. In many cases, the top surface of this partial chamber or chilled chamber may be used as an electromagnetic shield.

Further, a rear side electromagnetic wave shield 26b is provided to cover the electrode holding area 30 having the matching circuit 23 and the like provided on the rear side of the freezing/thawing chamber 6. By providing the electromagnetic wave shield 26b on the back side in this way, the electric field generated between the first electrode 24 and the second electrode 25 and the high frequency noise generated from the matching circuit 23 are prevented from being transmitted to the electrical components of the cooling fan 14 and the damper 12a. It is prevented from affecting the operation (control). Note that an electromagnetic shield (not shown) is also provided on the side surface of the freezing/thawing chamber 6.

Next, the door-side electromagnetic wave shield 26d provided on the door 29 that opens and closes the front opening of the freezing/thawing chamber 6 will be explained. Since the door 29 is configured to open and close with respect to the main body of the refrigerator 1, in a structure in which the electromagnetic wave shield provided on the door 29 is connected to the grounding part of the refrigerator 1 main body with a wired line, the wired line is extended when the door 29 is opened and closed. Repeated shrinkage causes metal fatigue to accumulate in the wired line. In such a connected configuration, it is not preferable to connect the door-side electromagnetic wave shield 26d provided on the door 29 to the grounding part of the refrigerator 1 using a wired line, since this may cause disconnection in the wired line.

Generally, in order to prevent electromagnetic wave leakage, when the door 29 is closed, the distance between the door-side electromagnetic wave shield 26d and the cross rail 21 (connected to the outer box 3, shown in FIG. 1), which serves as the electromagnetic wave shield on the main body side, is adjusted. , it is necessary to make it shorter than 1/4 of the wavelength λ of the electromagnetic wave. In Embodiment 1, the spacing is further reduced to obtain a contact effect without providing a wired line. For example, when the door 29 is closed, the distance between the door-side electromagnetic wave shield 26d and the cross rail 21 is set to 30 mm or less. Since the cross rail 21 connected to the outer box 3 is grounded, when the door 29 is closed, by placing the door-side electromagnetic wave shield 26d close to the cross rail 21, the same effect as grounding by a wired line can be obtained. can get. Further, by forming the end portion of the door-side electromagnetic wave shield 26d into a shape bent toward the main body of the refrigerator 1, it becomes easy to bring the door-side electromagnetic wave shield 26d close to the cross rail 21.

In addition to the cross rail 21, a configuration in which the electromagnetic shield 26 (26a, 26c) is placed close to the electromagnetic wave shield 26 may also be used.

Next, we will explain how to connect the electromagnetic shield and other circuits to the ground.

FIG. 10 is a schematic circuit diagram of an AC/DC converter that drives various circuits. In this circuit, the DC/DC converter after rectifying the AC commercial power supply ACV with the bridge diode BD1 and the rectifying capacitor C0 is a flyback type switching power supply circuit, but it is not limited to this; it is a forward type, push type, etc. Any switching power supply that uses a transformer, such as a pull type or half bridge type, will suffice. In addition, this circuit shows only the main circuit components, and the noise filter, power supply control circuit, and protection circuit are omitted.

The AC commercial power supply ACV is converted into a DC power supply by a bridge diode BD1 and a rectifying capacitor C0, and is referred to as a primary DC power supply DCV0 (first power supply unit). The zero volt reference potential of this primary side DC power supply DCV0 is defined as the primary side ground GND0 (first ground portion).

The primary DC power supply DCV0 is applied to the primary winding P1 of the switching transformer T1, and is switched at a frequency of several tens of kHz by the FET Q1. The power accumulated in the primary winding P1 is transmitted to the electrically insulated secondary winding S1 by electromagnetic induction, and is rectified by the secondary rectifier diode D1 and the secondary rectifier capacitor C1. Secondary side DC power supply DCV1 is output. In addition, the secondary winding S2 has an output section provided between both ends of the winding, and is rectified by a secondary rectifier diode D2 and a secondary rectifier capacitor C2, and has a voltage lower than that of the secondary DC power supply DCV1. A secondary voltage DC power supply DCV2 is output. The zero volt reference potential of the secondary DC power supplies DCV1 and DCV2 (second power supply section) is defined as a secondary ground GND1 (second ground section).

Further, the primary DC power supply DCV0 is branched and applied not only to the switching transformer T1 but also to the primary winding P2 of the switching transformer T2, and is switched at a frequency of several tens of kHz by the FET Q2. The power accumulated in the primary winding P2 is transmitted to the electrically insulated secondary winding S3 by electromagnetic induction, and is rectified by the secondary rectifier diode D3 and the secondary rectifier capacitor C3. A secondary side DC power supply DCV3 (third power supply unit) is output. The zero volt reference potential of this secondary DC power supply DCV3 is defined as a secondary ground GND2 (third ground portion).

The insulation between the primary winding P1 and the secondary winding S1 in the switching transformer T1, and the insulation between the primary winding P2 and the secondary winding S3 in the switching transformer T2 are made using Japanese electrical appliances. The insulation performance shall be higher than the basic insulation specified by safety laws or IEC standards.

In the oscillation circuit 22, a minute power of 40.68 MHz assigned to the ISM band is outputted by an oscillation source 22a using a crystal or the like, and after being slightly amplified by the first amplifier circuit 22b, it is further amplified by the second amplifier circuit 22c. The signal is amplified and output toward the matching circuit 23. Note that the output frequency of the oscillation source 22a is not limited to 40.68 MHz.

In this embodiment, the secondary DC power supply DC1 is connected to the second amplifier circuit 22c in the oscillation circuit 22, and the secondary DC power supply DC2 is connected to the oscillation source 22a in the oscillation circuit 22 and the first amplifier circuit 22b to receive reflected waves. A secondary side DC power supply DC3 is supplied to the detection section 51 and the matching circuit 23, and to the control section 50.

As a result, the circuit system that uses the secondary ground GND1 as a zero-volt reference potential includes the oscillation circuit 22, the input reflected wave detection section 51, the matching circuit 23, and the second electrode 25. Further, the circuit system that uses the secondary side ground GND2 as a zero volt reference potential is the control unit 50.

Each of the electromagnetic wave shields 26, 26a, 26b, the back side electromagnetic wave shield 26b, and the door side electromagnetic wave shield 26d is insulated from the second electrode 25 (same potential as the secondary side ground GND1), or is not insulated. Although not necessarily connected to the second electrode 25, it is desirable that it be connected to the second electrode 25 at a distance of a certain distance or more. This reduces the electric field and magnetic field applied to each electromagnetic shield, and also suppresses leakage to the outside. That is, the effect of electromagnetic shielding becomes higher.

There are several ways to increase the effectiveness of electromagnetic shielding, and these are explained below.

One method is to not connect each electromagnetic wave shield to any of the primary ground GND0, secondary ground GND1, and secondary ground GND2. This method is particularly effective when the total area or total volume of the electromagnetic wave shield is greater than a certain level, and there is little chance of harmful effects caused by noise such as leakage of high frequencies to the outside through the ground line.

Moreover, one is means for connecting each electromagnetic shield to the primary side ground GND0. The primary ground GND0 is normally connected to the outer box 3 made of a metal material, and has a large ground area. Therefore, the zero volt reference potential of the primary ground GND0 is the most stable, and not only are the electromagnetic wave shields highly effective, but malfunctions due to noise are also rare.

Moreover, one is means for connecting each electromagnetic wave shield to the secondary side ground GND2. This means that the second electrode 25 and each electromagnetic wave shield are insulated at two stages of switching transformers T1 and T2, so that high frequency noise is less likely to leak from the first electrode 24 to each electromagnetic wave shield, and the second electrode The electric field generation to 25 becomes stable.

One method is to connect each electromagnetic shield to the secondary ground GND1, but to connect it to the second electrode 25 at a location more than a certain distance away, at least on the outside of each electromagnetic shield. This means obtains a certain shielding effect, makes it difficult for high frequency noise to leak from the first electrode 24 to each electromagnetic wave shield, and stabilizes the electric field generation to the second electrode 25.

The effectiveness of the above means for increasing the shielding effect may vary depending on the structure and wiring of the system, so the optimal one should be selected in consideration of the electric field generation efficiency from the first electrode 24 to the second electrode 25 and the electromagnetic wave shielding effect. There is a need to.

In addition, in the refrigerator 1 of the first embodiment, since the outer box 3 is made of a steel plate, this steel plate itself has a function as an electromagnetic wave shield. Therefore, electromagnetic waves inside the refrigerator 1 are reliably prevented from leaking to the outside of the refrigerator 1.

In the configuration of the electromagnetic shield described above, malfunctions and radio wave leakage due to normal mode noise generated within the system and common mode noise conducted to the secondary ground 1 or the secondary ground 2 may pose problems. In particular, common mode noise is often superimposed on the cable that conducts the high frequency output generated by the oscillation circuit 22, and the noise is often radiated from the cable surface. For this reason, coaxial cables are usually used to conduct high-frequency output, but common mode noise can also be conducted to the outside of the outer conductor, which originally serves as a shield, within the coaxial cable.

FIGS. 19a and 19b show a configuration that prevents malfunctions and radio wave leakage due to common mode noise. In FIG. 19a, the oscillation circuit 22 and the incoming reflected wave detection section 51 are arranged at a location away from the electrode holding substrate 52 including the matching circuit 23, etc., and the coaxial cable 56a connects the electrode holding substrate 52 and the incoming reflected wave detection section. 51 are electrically connected. The outer shell of the outer box 3a of the refrigerator is made of a metal material, and the coaxial cable 56 is wired inside the outer box 3a to prevent leakage radio waves emitted due to common mode noise conducted to the coaxial cable 56. This prevents the air from spreading outside the refrigerator.

In FIG. 19a, the coaxial cable 56a is wired inside the outer box 3a so as to be in contact with it at at least one location. Since the outer box 3a has a large area and has a reference potential that is almost the same as the potential of GND0 shown in FIG. 10, it has the effect of letting the common mode noise conducted to the coaxial cable 56 to the GND0 side.

Further, in FIG. 19b, the coaxial cable 56 is wired inside the outer box 3a, but the coaxial cable 56b is wired so as not to touch the inside of the outer box 3a.

The configuration of FIG. 19a or the configuration of FIG. 19b is selected depending on the path through which common mode noise is conducted through the coaxial cable 56 and the outer box 3a, which can suppress malfunctions and radio wave leakage.

Note that the arrangement relationship between the coaxial cables 56a and 56b and the outer box 3a must be wired to ensure the configuration shown in FIG. 19a or 19b, and the design is such that it is unclear which wiring state will be used during the mass production process. is not desirable.

[1-7. Configuration of the first electrode and second electrode and thawing performance due to the configuration]
FIG. 11 is a plan view of the first electrode 24 and second electrode 25 on the top side of the freezing/thawing chamber 6, viewed from above.

As shown in FIG. 11, the first electrode 24 has a slightly smaller area than the second electrode 25. Further, a plurality of electrode holes 41 and 42 are formed in the first electrode 24 and the second electrode 25, and the plurality of electrode holes 41 and 42 are connected to the positive terminals 24a to 24c and the cathode terminal of the second electrode 25. It has a vertically long slit shape extending from the back side of the refrigerator interior where 25a to 25c are provided toward the front side. With such a shape, the high frequency current input from the positive electrode terminals 24a to 24c side easily flows from the back side of the refrigerator toward the front side, and the electric field strength generated between the two electrodes becomes slightly stronger.

Further, the electrode holes 41 and 42 provided in the first electrode 24 and the second electrode 25 are not vertically symmetrical, but are shifted by about half the breadth of the electrode hole 41. Since a plurality of electrode holes 41 are formed on the electrode surface of the first electrode 24, the region where a strong electric field is formed on the electrode surface of the first electrode 24 is uniformly distributed, and the dielectric The configuration allows for uniform heating. That is, the edge of the opening in the electrode hole 41 becomes an electric field concentration region.

Note that the shape and arrangement of the electrode holes 41 and 42 shown in FIG. Designed accordingly. For example, the shape of the electrode holes 41 and 42 may be a new circle, and the electrode holes 41 of the first electrode 24 and the second electrode 25 are not vertically symmetrical, but are arranged offset by about half the hole diameter. is desirable.

In the configuration of Embodiment 1, the shape and arrangement of the electrode holes 41 of the first electrode 24 are described as a configuration in which a plurality of electrode holes 41 are arranged, but the present invention is not limited to such a configuration. For example, the first electrode 24 may have a shape in which at least one opening is formed, and the edge of the opening becomes an electric field concentration region where the electric field is concentrated on the electrode surface of the first electrode 24. . That is, the present invention may be configured as long as the electric field concentration region is dispersed on the electrode surface of the first electrode 24. In addition, in the first embodiment, a configuration in which a plurality of electrode holes 42 are provided on the electrode surface of the second electrode 25 has been described, but in the present invention, a configuration in which a plurality of electrode holes 42 are provided in the second electrode 25 is described. The opening is not limited to the above, and may be any opening formed so as to form a desired electric field between the first electrode 24 and the electrode.

The electrode holding substrate 52 is configured to securely hold the first electrode 24 and the second electrode 25 with a predetermined interval (H in FIG. 8), and the electrode interval H is equal to the distance between the first electrode 24 and the second electrode 25. It is made shorter than the long side dimension (D in FIG. 11). Note that if the first electrode is circular, it is desirable to configure the electrode spacing H to be shorter than its diameter, and if it is elliptical, the electrode spacing H is shorter than its major axis.

FIG. 12 shows the relationship between the electrode spacing H (see FIG. 8) between the first electrode 24 and the second electrode 25 and the electric field strength between the two electrodes. As shown in FIG. 12, the electric field strength tends to become weaker as the electrode interval H becomes wider. In particular, when the electrode spacing H1 (100 mm) is exceeded, the electric field strength decreases significantly, and when the electrode spacing H2 (125 mm) is exceeded, the electric field strength decreases to a level at which high frequency heating ability cannot be obtained. From the above, the electrode spacing H is desirably 100 mm or less, and needs to be at least 125 mm or less.

The inventor used a freezing/thawing chamber 6 having the electrode configuration of Embodiment 1 and, as a comparative example, a freezing/thawing chamber 6 having an electrode configuration including a second electrode 25 having no electrode hole. We performed a simulation of the electric field generation between the electrodes.

FIG. 13A is a diagram showing the results of a simulation performed with an electrode configuration in which the first electrode 24 or the second electrode 25 without an electrode hole is provided. FIG. 13B is a diagram showing the results of a simulation performed with an electrode configuration in which the first electrode 24 or the second electrode 25 having an electrode hole is provided. In FIGS. 13A and 13B, dark colored parts are regions where the electric field is concentrated. As is clear from this electric field simulation diagram, compared to the electric field simulation diagram of FIG. 13A, in the dielectric heating configuration of FIG. 13B, electric field concentration is relaxed throughout the electrode, and the electric field is made more uniform. I can understand.

As shown in FIG. 11, by arranging the electrode hole 41 of the first electrode 24 and the electrode hole 42 of the second electrode 25 so that their central axes extending in the vertical direction (opposing direction) do not coincide with each other, the entire electrode The electric field concentration is relaxed at . Note that in an electrode configuration in which the electrode hole 41 of the first electrode 24 and the electrode hole 42 of the second electrode 25 are arranged so that their central axes extending in the vertical direction (opposing direction) are aligned, the electrode hole 41 and the electrode hole 42 of the second electrode 25 do not have an electrode hole. Compared to the configuration in which no second electrode 25 is provided, the concentration of the electric field is alleviated, and especially the concentration of the electric field at the corner portions is alleviated.

The freezing/thawing chamber 6 in the refrigerator 1 of the first embodiment has a configuration in which a storage case 31 is fixed to the back side of the door 29, as shown in FIGS. 2 and 3. The storage case 31 is configured to move back and forth inside the freezing/thawing chamber 6 as the door 29 opens and closes. In the configuration of the first embodiment, rails are provided on both sides of the freezing/thawing chamber 6 so that the storage case 31 can move smoothly inside the freezing/thawing chamber 6. Further, sliding members that slide on the rails are provided on both outer sides of the storage case 31. These rails and sliding members of the frame are provided at positions away from the dielectric heating area, which is the area where the first electrode 24 and the second electrode 25 of the freezing/thawing chamber 6 face each other, so as not to be dielectrically heated. There is.

[1-8. Heat treatment operation by electric field generation]
In the refrigerator 1 of the first embodiment, when an electric field generation command is input, an electric field generation process is performed for the space between the first electrode 24 and the second electrode 25 of the freezing/thawing chamber 6. In the electric field generation process in the first embodiment, as will be described later, the control unit 50 controls the dielectric heating mechanism including the oscillation circuit 22, the input reflected wave detection unit 51, and the matching circuit 23, and also controls the compressor 19 and the cooler. It controls a cooling mechanism including a refrigeration cycle such as 13, and a cold air introduction mechanism including a cooling fan 14 and a damper 12a.

In the electric field generation process in the first embodiment, a predetermined high frequency voltage is applied between the first electrode 24 and the second electrode 25, and the food, which is a dielectric material, is dielectrically heated by the high frequency electric field between the electrodes. During this dielectric heating, the control unit 50 controls the opening and closing of the damper 12a to continuously or intermittently introduce cold air. FIG. 14 shows an example of the waveforms of the control signals of the dielectric heating mechanism (oscillation circuit 22) and cold air introduction mechanism (damper 23) in the electric field generation process, and also shows the food temperature at that time, the room temperature of the freezing/thawing chamber 6, and The humidity in the freezing/thawing chamber 6 is shown.

A configuration that uses VHF waves as the frequency characteristic for electric field generation processing is less likely to cause "partial boiling" than a configuration that uses microwaves, but in order to further improve the uniformity of thawing, the implementation In the refrigerator 1 of the first embodiment, an electrode holding substrate 52 is provided, and the first electrode 24 and the second electrode 25, which are substantially planar plate-like members, are arranged at a predetermined interval (H in FIG. 8). The structure is such that it is held securely in parallel.

As shown in FIG. 14, when performing defrosting processing, for example, when an electric field generation command is input (defrosting start), the oscillation circuit 22 is turned on, and a high frequency voltage of, for example, 40.68 MHz is applied to the first electrode 24 and the first electrode 24. The voltage is applied between the two electrodes 25. At this time, since the damper 12a is in an open state, the room temperature of the freezing/thawing chamber 6 is maintained at the freezing temperature t1 (for example, -20° C.). The damper 12a is closed after a predetermined period of time has passed since the start of defrosting. When the damper 12a is closed, the room temperature of the freezing/thawing chamber 6 begins to rise. In the electric field generation process in Embodiment 1, by performing dielectric heating and controlling the opening and closing of the damper 12a, an increase in the surface temperature of the frozen product is suppressed and thawing is performed without causing so-called "partial boiling". There is.

The opening/closing control of the damper 12a is performed based on the ratio of the reflected wave to the incident wave detected by the incident reflected wave detection unit 51 with respect to the electromagnetic wave matched by the matching circuit 23 and supplied between the first electrode 24 and the second electrode 25. This is performed by the control unit 50 based on (reflectance). When the reflectance reaches a preset threshold and becomes large, the control unit 50 opens the damper 12a to lower the internal temperature of the freezing/thawing chamber 6. In this way, cold air is intermittently introduced into the freezing/thawing chamber 6 by controlling the opening and closing of the damper 12a, so that the stored items in the storage space (electric field generation space) of the freezing/thawing chamber 6 are maintained in the desired frozen state. While dielectrically heating, the desired thawed state is achieved.

The electric field generation process is completed when the desired thawing state is reached, but in order to detect the desired thawing state at which the electric field generation process is completed, reflectance is used in the electric field generation process of the first embodiment. It is being As the preserved material progresses in melting by dielectric heating, the number of melted water molecules in the preserved material increases. As the number of molten water molecules in the stored material increases, the dielectric constant changes and the impedance matching shifts. As a result, the reflectance, which is the ratio of reflected waves to output electromagnetic waves, increases. In the electric field generation process, when the reflectance increases and reaches a preset threshold, the matching circuit 23 performs impedance matching to reduce the reflectance.

The completion of decompression in the electric field generation process of the first embodiment is detected when the reflectance after impedance matching by the matching circuit 23 exceeds the threshold for completion of decompression. The thawing completion threshold detects when the thawing of the stored material has reached a desired thawing state. Here, the thawing state in which the preserved material is desired to be thawed is a state in which the woman can cut the preserved material with one hand and the amount of dripping from the preserved material is extremely small. The threshold for completion of thawing is a value determined in advance through experiments.

As shown in FIG. 14, by controlling the opening and closing of the damper 12a, relatively low-humidity cold air passing through the air passage 12 is supplied from the cold air introduction hole 20 to the freezing/thawing chamber 6. /The humidity in the thawing chamber 6 does not reach 100%, and dew condensation in the freezing/thawing chamber 6 is prevented.

Note that the method for calculating the reflectance in the present embodiment is not limited to the ratio (reflectance) of the reflected wave to the incident wave detected by the incident reflected wave detection unit 51, and for example, the method for calculating the reflectance may be performed by detecting only the reflected wave. , a method of calculating the ratio with the output set in advance by the oscillation circuit 22 may also be used.

Further, the electric field generation process may be controlled only by the reflected wave detected by the input reflected wave detection section 51 regardless of the output, instead of the reflectance. The same applies to control using reflectance described in the following explanation.

[1-9. Storage operation by electric field generation]
FIG. 15 is a flowchart showing control for performing cooling and electric field generation processing to bring the food into an arbitrary state in the freezing/thawing chamber 6. Each step shown in the flowchart of FIG. 15 is performed by the CPU of the control unit 50 executing a control program stored in a memory such as a ROM. As described above, when the reflectance after performing impedance matching by the matching circuit 23 in the electric field generation process exceeds the threshold for completion of decompression, the control after the completion of the electric field generation process shown in FIG. 15 is performed. For example, the preserved item may be maintained in a desired thawed state after the thawing process is completed. One of the means for this is to set the room temperature of the freezing/thawing chamber 6 to a so-called slightly freezing temperature range, for example, about -1°C to -3°C. Alternatively, the room temperature of the freezing/thawing chamber 6 may be set in the freezing temperature range, for example, -18°C to -20°C, and cooling may be achieved by applying a high-frequency electric field with reduced output, or by intermittently applying high-frequency waves. This involves heating and maintaining the stored material within a desired temperature range. Furthermore, the room temperature of the freezing/thawing chamber 6 can be changed periodically. For example, by periodically changing the temperature from -12°C to -5°C, the composition of the food is affected. In the above, cooling and heating are performed by applying a high-frequency electric field with reduced output or by intermittently applying high-frequency waves to maintain the stored item within a desired temperature range.

As shown in step 101 of FIG. 15, after the start of the preservation processing operation, the presence or absence of the preservation object in the freezing/thawing chamber 6 is always detected (step 101). To detect the presence or absence of stored items in the freezing/thawing chamber 6, constantly detected reflectance is used. Therefore, the matching circuit 23 is always operated intermittently, and low-power electromagnetic waves are intermittently output from the first electrode 24. The control unit 50 compares the reflectance with a preset threshold for the presence or absence of a preserved object, and determines whether there is a preserved object in the freezing/thawing chamber 6.

In step 101, when it is detected that there is no stored item in the freezing/thawing chamber 6, the room temperature of the freezing/thawing chamber 6 is set to a freezing temperature range, for example, -18°C to -20°C (step 105). .

In step 101, when it is detected that there is a preserved item in the freezing/thawing chamber 6, it is determined whether the existing preserved item includes an unfrozen item after thawing based on a change in reflectance. do.

Note that even if the electric field generation process for the preserved object is completed, the user may not immediately take out the preserved object from the freezing/thawing chamber 6. In such a case, the refrigerator 1 of the first embodiment is configured to maintain a slight freezing temperature range for a predetermined period of time in which the desired thawing state of the stored items in the freezing/thawing chamber 6 can be maintained. If the stored item is stored for longer than this predetermined time, in order to maintain the freshness of the stored item, in the refrigerator 1 of the first embodiment, the room temperature of the freezing/thawing chamber 6 is shifted to the freezing temperature range. control. In step 102, even if it is determined that the time after thawing has been completed has exceeded the predetermined time while thawed preserved items are stored, the process proceeds to step 105 and the room temperature of the freezing/thawing chamber 6 is set to the freezing temperature. A freezing process is carried out.

When it is determined that there is no thawed unfrozen food stored in the freezing/thawing chamber 6, for example, if the food temperature exceeds the target temperature in step 103, a freezing operation is performed (step 105); If the temperature is not exceeded, an electric field is generated to raise the temperature of the food.A specific example of this control is described below. The refrigerator 1 of the first embodiment performs dielectric heating to freeze and preserve food in a desired state during the freezing process in which the room temperature of the freezing/thawing chamber 6 is maintained within the freezing temperature range. It is configured. Generally, when food is frozen, frost formation occurs on the inner surface of the food packaging material due to moisture in the freezing/thawing chamber 6 and moisture inside the food. When such frost formation occurs on the surface of food, the food becomes dry and dry, and the food is no longer tasty and fresh (``freezer burn''). In order to prevent such a situation, in the refrigerator 1 of the first embodiment, the dielectric heating operation is performed simultaneously with the cooling operation.

16A and 16B are waveform diagrams showing the states of each element during cooling operation. FIG. 16A is a waveform diagram showing a cooling operation during frozen storage in a conventional refrigerator, and FIG. 16B is a waveform diagram showing a cooling operation performed in the freezing/thawing chamber 6 in the refrigerator 1 of the first embodiment.

In FIG. 16A, (1) is a waveform diagram showing ON/OFF of the cooling operation. Turning the cooling operation ON/OFF corresponds to, for example, opening/closing a damper, turning ON/OFF a compressor, and the like. ON indicates a state in which cold air is introduced into the freezer compartment, and OFF indicates a state in which the damper is closed and the introduction of cold air into the freezer compartment is blocked. Therefore, as shown in the waveform diagram (2) of FIG. 16A, the temperature of the food in the freezing chamber will fluctuate vertically around the preset freezing temperature (for example, -20° C.) T1. As a result, moisture evaporation and frost formation occur repeatedly on the surface of the food in the freezing chamber, and the food may not be in a desired frozen state.

On the other hand, in FIG. 16B showing the cooling operation of the first embodiment, unlike the conventional cooling operation, the food is cooled and dielectrically heated. (1) of FIG. 16B is a waveform diagram showing the opening/closing operation of the damper 12a, and ON indicates the open state of the damper 12a, and cold air passes through the air path 12 and exits the cold air introduction hole 20 into the freezing/thawing chamber. 6 has been introduced. OFF indicates a closed state of the damper 12a, and the introduction of cold air into the freezing/thawing chamber 6 is blocked. Since cold air introduction in the cooling operation of the first embodiment is performed simultaneously with dielectric heating, the cold air introduction time is set longer than in the conventional example, that is, the cooling capacity is increased.

(2) of FIG. 16B is a waveform diagram showing the operating state of dielectric heating when the oscillation circuit 22 is drive-controlled. When the damper 12a is in the open state, dielectric heating is simultaneously performed.

In the cooling operation in the first embodiment, dielectric heating is performed with a smaller output than in the defrosting operation. The output power is adjusted by supplying power to the oscillation circuit 22 or by PWM control of the oscillation circuit 22.

As a result, as shown in (3) of FIG. 16B, the food temperature in the freezing/thawing chamber 6 is maintained at the preset freezing temperature (for example, -20°C) T1, and fluctuations in food temperature are suppressed. ing.

According to experiments, frost formation could be eliminated if the food temperature fluctuation was about 0.1 K or less. At least the less fluctuations in food temperature are reduced, the more frost formation can be suppressed. Further, inside the food, dielectric heating is performed at the same frequency as during thawing and with a smaller output power than during thawing, which has the effect of suppressing the expansion of ice crystals. When dielectric heating is performed, the electric field tends to gather at the tips of ice crystals formed in the food, so even if the temperature in the freezing/thawing chamber 6 is below the maximum ice crystal formation zone, the ice crystals will slowly grow. It only grows.

As described above, in the refrigerator 1 of the first embodiment, the dielectric heating operation is performed even during the cooling operation during frozen storage, so it is possible to freeze stored frozen products in a desired state. becomes.

[1-10. Freezing operation due to electric field generation]
In the refrigerator 1 of the first embodiment, it is possible to perform freezing processing on unfrozen food newly placed in the freezing/thawing chamber 6 based on a user's command from the operation unit 47. be. FIG. 17 is a waveform diagram showing the state of each element in a rapid cooling operation that is a freezing process. In FIG. 17, (a) is a graph showing whether or not there is a preserved object (food) in the freezing/thawing chamber 6. In FIG. The controller 50 determines whether there is a preserved object in the freezing/thawing chamber 6 based on the ratio (reflectance) of the reflected wave detected by the incoming reflected wave detector 51 and the output electromagnetic wave. be judged. (b) of FIG. 17 shows that the control section 50 intermittently acquires information from the matching circuit 23 and the input reflected wave detection section 51. FIG. 17(c) is a graph showing an example of changes in reflectance. The control unit 50 determines that food, which is a preserved item, has been placed in the freezing/thawing chamber 6 when the reflectance is equal to or less than the first threshold value R1.

In the rapid cooling operation for the food stored in the freezing/thawing chamber 6, the rotation speeds of the compressor 19 and the cooling fan 14 of the cooling mechanism are increased to enhance the cooling capacity and forced continuous operation is performed. Further, the cold air introduction mechanism is controlled so that the damper 12a of the air passage 12 leading to the freezing/thawing chamber 6 is forced to be continuously opened, and cold air is introduced (see FIG. 17(d)). (See waveform diagram).

In the rapid cooling operation, a dielectric heating operation is performed to suppress the elongation of ice crystals when the food temperature is in the maximum ice crystal formation zone (approximately -1°C to approximately -5°C). The dielectric heating operation at this time has a lower output of several tens of W or less than that during thawing, and dielectric heating is performed intermittently (period h in FIG. 17(e)). Detection that the food temperature has entered the zone of maximum ice crystal formation to initiate the dielectric heating operation is sensed by an increased change in reflectance as the food passes through the latent heat region. In the first embodiment, when the detected reflectance falls within a preset second threshold R2, the dielectric heating operation is started (see FIG. 17(e)). Note that the region where the reflectance is from the second threshold R2 to the third threshold R3 is the maximum ice crystal formation zone of the food, and the dielectric heating operation is continued for a predetermined period of time after the reflectance reaches the third threshold R3. When (t2) has elapsed, it is determined that the food has passed through the maximum ice crystal formation zone, and the dielectric heating operation is stopped.

As described above, when it is determined that the food has passed through the maximum ice crystal formation zone, the dielectric heating operation is stopped, the rapid cooling operation is ended, and the normal cooling operation is started. In this way, even when performing a rapid cooling operation, by performing the dielectric heating operation for a desired period, the food can be brought into a preferable frozen state.

[1-11. Safety control using door switch]
In this embodiment, as described above, in order to prevent electromagnetic waves from leaking to the outside of the refrigerator 1, the electromagnetic wave shield 26 is provided to surround the freezing/thawing chamber 6. Further, since the outer box 3 is made of a steel plate, and this steel plate itself has a function as an electromagnetic wave shield, leakage of electromagnetic waves to the outside is prevented as long as the door 29 is closed.

However, when the door 29 is opened, electromagnetic waves may leak from the opening. Additionally, there is a risk that high frequency waves may be applied to the human body if the user inserts his or her hand into the refrigerator through the opening, so countermeasures are required.

Therefore, in this embodiment, when the door opening/closing detection means 55a (see FIG. 9) detects that the door 29 is open, the oscillation circuit 22 is stopped and the first Power supply to the electrode 24 is stopped. Note that a refrigerator generally has multiple doors, but if the electromagnetic shield 26 is functioning sufficiently, the door opening/closing detection means 55b of the refrigerator compartment 5 and the door opening/closing detection means of the ice making compartment 7. 55c, even if the opening/closing detection means 55d of the door of the freezer compartment 8 and the opening/closing detection unit 55e of the vegetable compartment door detect that a door of a storage room other than the freezing/defrosting compartment 6 has been opened, electromagnetic waves exceeding the specified level will not leak to the outside. Since there is no signal, the oscillation circuit 22 does not stop and continues to operate.

However, this does not apply if the electromagnetic wave shield 26 cannot sufficiently surround the freezing/thawing chamber 6 due to design issues.

For example, if the electromagnetic wave shield 26 cannot be constructed on the top of the freezing/thawing chamber 6, the oscillation circuit 22 is stopped when the door of the storage chamber (refrigerating chamber 5 in the layout of FIG. 1) located above is opened. In addition, if the electromagnetic wave shield 26 cannot be configured at the bottom of the freezing/thawing compartment 6, and the doors of the storage compartments (freezer compartment 8 and vegetable compartment 9 in the layout of FIG. 1) located below are opened, the oscillation circuit 22 to stop. Furthermore, if the electromagnetic shield 26 cannot be configured on the side of the freezing/thawing chamber 6, the oscillation circuit 22 is stopped when the door of the storage chamber (ice making chamber 7 in the layout of FIG. 1) on that side is opened. . In this manner, the oscillation circuit 22 is stopped when the door of the storage room is opened in a direction in which the electromagnetic wave shield 26 cannot be configured, thereby preventing leakage of electromagnetic waves.

As means for stopping the oscillation circuit 22, there are the following means.

FIG. 18A shows means for cutting off the power supply from the power supply unit 48 to the oscillation circuit 22 by the door opening/closing detection means 55a. The door opening/closing detection means 55a is a switch mechanism that is turned on when the door 29 is closed and cut off when the door 29 is opened, and when the switch is cut off, the power supply to the oscillation circuit 22 is cut off. Make sure to stop the operation.

Further, FIG. 18B shows means for stopping the operation of the power supply control section 48a that controls the power supply section 48 by the door opening/closing detection means 55a. The door opening/closing detection means 55a is a switch mechanism similar to that shown in FIG. 18A, and when the door 29 is opened, the power supply to the power supply control section 48a is stopped, and the power supply from the power supply section 48 to the oscillation section 22 is also cut off and stopped. . In FIG. 18B, the operation is stopped by cutting off the power supply to the circuit in the power supply control unit 48a, but there is a method for making the overcurrent protection circuit in the power supply control unit 48a recognize an overcurrent state and stopping the operation, and It may also be a means for recognizing that the section 48 has become overloaded and stopping it.

Further, in FIG. 18C, the open/close state of the door 29 can be determined not only by the door open/close detector 55a but also by the magnetic sensor 55f. The magnetic sensor 55f outputs an opening/closing signal for the door 29 to the control section 50, and the control section 50 receives the signal from the magnetic sensor 55f and outputs an operation enable/disable signal for the power supply control section 48a. A door opening/closing detection means 55a is further inserted between the magnetic sensor 55f and the control unit 50, which is electrically connected when the door 29 is closed, and is cut off when the door 29 is open, so that no signal can be output. The operation of the power supply section 48 is stopped.

Since the above-described power supply or control signal conduction/cutoff is realized by hardware, the resistance to high frequency noise or external noise is high, and malfunctions are difficult to occur.

In addition, in FIGS. 18B and 18C, the door opening/closing detection means 55a is a switch mechanism that is turned on when the door 29 is closed and cut off when the door 29 is opened, but when the door 29 is closed, It is also possible to use a device that is shut off and conductive when the door 29 is opened. At this time, it is necessary to reverse the H/L logic for stopping the power supply control section 48a.

In addition, in the refrigerator of Embodiment 1, although the structure which had the freezing function and the thawing function was demonstrated as the freezing/thawing chamber 6, the structure which was made into the thawing chamber only with a thawing function may be sufficient.

As described above, in the refrigerator of the present disclosure, as explained in Embodiment 1, the electric field is made uniform in the thawing space of the freezing/thawing chamber, and the electric field is applied to stored items held in the thawing space. Desired dielectric heating can be performed during generation and freezing treatments. Therefore, according to the refrigerator of the present disclosure, the refrigerator can freeze, store, and thaw stored items stored in the storage chamber in a desired state, and has highly reliable cooling, storage, and thawing functions. can be provided. In other words, it has the excellent effect of being able to freeze preserves in a desired state and thaw frozen preserves in a desired state into a desired state in a short period of time. By using the dielectric heating mechanism, it is possible to downsize the refrigerator with a defrosting function.

[2-1. Effects, etc.]
As described above, a refrigerator according to an aspect of the present disclosure includes at least one storage chamber having a space capable of storing stored items, an oscillating section that generates high-frequency power, and an electric field that receives the high-frequency power generated from the oscillating section. a first electrode and a second electrode that cause the oscillation to occur in the storage space; a load impedance formed by the first electrode, the second electrode, and the stored object stored in the storage space; A matching section that matches the output impedance of the section, a high frequency wiring that directly or indirectly connects the oscillating section and the matching section, and a noise suppressing means that prevents noise leakage from the high frequency wiring. This makes it possible to suppress malfunctions caused by high-frequency noise and leakage of radio waves to the outside.

As above, the present invention has been described in the embodiments with a certain degree of detail, but the contents disclosed in the first embodiment should change in the details of the configuration, and the elements in the embodiments may be replaced, combined, and Changes in the order may be made without departing from the scope and spirit of the claimed invention.

In the refrigerator of the present invention, it is possible to freeze, store, and thaw preserved items in a desired state, thereby increasing added value, reliability, and safety of the refrigerator, and having high market value. , can be suitably applied to various refrigerators.

1 Refrigerator 3, 3a Outer box 4 Inner box 5 Refrigerator room 6 Freezing/thawing room (storage room)
7 Ice making compartment 8 Freezer compartment 9 Vegetable compartment 10 Machine compartment 11 Cooling compartment 12 Air path 12a Damper 13 Cooler 14 Cooling fan 15 Defrost heater 16 Drain pan 17 Drain tube 18 Evaporation dish 19 Compressor 20 Cold air introduction hole 21 Cross rail 22 Oscillation Circuit (oscillation section)
22a Oscillation source 22b First amplifier circuit 22c Second amplifier circuit 23 Matching circuit (matching section)
24 First electrode 24a to 24c Positive terminal 25 Second electrode 25a to 25c Cathode terminal 26 Electromagnetic shield (shield part)
26a Top side electromagnetic wave shield 26b Rear side electromagnetic wave shield 26c Bottom side electromagnetic wave shield 26d Door side electromagnetic wave shield 29 Door 30 Electrode holding area 31 Storage case 32a to 32c Inner surface member 36 Gasket 40 Heat insulating material 41 Electrode hole (first electrode hole)
42 Electrode hole (second electrode hole)
47 Operation unit 48 Power supply unit 49 Temperature sensor 50 Control unit 51 Incoming reflected wave detection unit 52 Electrode holding board 53 Frame 54 Supports 55a to f Door opening/closing detection means 56a, b Coaxial cable D Long side dimension of first electrode H Installation interval ( electrode spacing)

Claims (4)

at least one storage room having a space capable of storing preserved items;
an oscillator that generates high-frequency power;
a first electrode that receives high frequency power generated from the oscillator and generates an electric field in the storage space, and a second electrode;
a load impedance formed by the first electrode, the second electrode, and the stored object stored in the storage chamber; and a matching part that matches the output impedance of the oscillation part.
high frequency wiring that directly or indirectly connects the oscillation section and the matching section;
A refrigerator comprising a noise suppressing means for preventing noise leakage from the high frequency wiring. A metal casing is provided to surround the outside of the storage chamber,
2. The refrigerator according to claim 1, wherein the noise suppressing means has a configuration in which most of the high-frequency wiring is wired inside the metal casing. 3. The refrigerator according to claim 1, wherein the noise suppressing means is configured such that the inside of the metal casing and the high-frequency wiring are in contact with each other at at least one location. 3. The refrigerator according to claim 1, wherein the noise suppressing means is configured so that the inside of the metal casing and the high-frequency wiring do not come into contact with each other within a distance of 50 cm from the matching section.