JP2006153350A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a refrigerator of high safety capable of preventing ignition, explosion or the like of a gas leaked in the refrigerator by spark even when the spark is generated in breaking a varistor element by the application of abnormal voltage or the like simultaneously with the leakage of a HC refrigerant gas into the refrigerator and further into a board storing portion of a control box as an internal back face wall, with respect to the refrigerator wherein an electron board is installed inside of the board storing portion in the control box in the refrigerator. <P>SOLUTION: This refrigerator includes a refrigerator main body having a refrigerating compartment or the like, and a cooler for creating the cold air supplied into the refrigerator, and further comprises a refrigerant circuit applying a flammable refrigerant as a refrigerant, the electronic board for control comprising the varistor having a characteristic to protect other electronic components by generating heat and broken to the application of abnormal voltage, the control box mounted on a back face in the refrigerating compartment and having the board storing portion for storing the electronic board, a varistor storing portion surrounding the varistor with the electronic board and having a structure to almost seal a space of the varistor, and a sealing member for covering an opening portion of the board storing portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigerator in which an electronic substrate is installed in a cabinet.

  Usually, a refrigerator has a control electronic board to perform various controls. If an abnormal voltage or lightning surge is applied to the electronic board through the power cord while the refrigerator is in operation, May fail. In the event of an electronic board failure, the electronic board of the refrigerator generates heat or breaks down due to abnormal voltage application or lightning surge intrusion for the purpose of protecting the electronic board without providing an expensive service of replacing the electronic board. It has a varistor element with the characteristic to protect Since only the varistor element is destroyed when a lightning surge enters, it can be easily repaired by replacing the varistor element.

  Conventionally, many medium to large refrigerators have an electronic board storage box at the upper back, but small refrigerators often have a board stored in the cabinet from the viewpoint of cost and service.

  Moreover, since medium to large refrigerators are heavy, a caster for movement is attached to the bottom. On the other hand, a small refrigerator is lighter than a large refrigerator and has a moving caster unlike a large refrigerator to reduce costs. In normal homes, refrigerators are placed so that the back of the refrigerator runs along the wall, but if a caster is attached, the refrigerator can be easily pulled out to the front even when a single person performs a service such as replacing the board of a large refrigerator. Is possible.

  On the other hand, the only way to go around the back of a refrigerator without a caster is to lift the refrigerator or drag the refrigerator. In the case of one person's service work, there is a great risk of damaging the floor by dragging the legs of the refrigerator. For this reason, in refrigerators without casters, there are many types of refrigerators in which electronic boards are placed in the cabinet to facilitate services such as board replacement, especially the back wall inside the plastic parts cabinet is stored in the board. Many types are used as control boxes with parts.

  Although the electronic board is in the cabinet, the electronic board generates heat, and if it comes into contact with the low outside air in the warehouse, there is a risk of dew condensation and a short circuit or ignition, and it may also ignite due to a substrate failure. The electronic substrate is substantially sealed with a flame retardant tape so as to cover the electronic substrate and the opening of the substrate storage portion.

  Since this type of refrigerator has used R134a refrigerant (non-combustible), which is a type of Freon gas, until now, gas leaks into the cabinet due to broken piping of the cooler, etc., and the substrate is stored in a substantially sealed structure. Even if gas enters the unit and the varistor element breaks down due to the application of abnormal voltage, etc., and a spark occurs, the refrigerant is non-flammable, and the refrigerant will ignite, explode, fire in the chamber, etc. There was no.

  In recent years, refrigerators in which the refrigerant in the refrigeration cycle is changed to a hydrocarbon-based refrigerant (hereinafter referred to as HC refrigerant), which is a flammable refrigerant, are increasing in order to cope with the ozone layer destruction caused by chlorofluorocarbon gas and the problem of global warming. HC refrigerant is an environmentally friendly gas, but care must be taken because it has the property of burning when it reaches a certain temperature in a certain concentration range.

  2. Description of the Related Art Conventionally, in a refrigerator having a substrate storage box at the upper back of a large refrigerator or the like, the substrate storage box is stored inside the refrigerator, and is separated from the outside air by a wall so that it hardly enters. Furthermore, since the substrate storage box is at a high position, even if gas leaks to the outside air, it is unlikely that the concentration of the outside air at the substrate storage box position will be higher than the combustion concentration, so it can be said that there is no ignition of the gas. .

  In a refrigerator using a conventional HC refrigerant, if a gas leak occurs in the machine room at the lower back, the electrical contact part in the machine room is isolated from the full part of the leaked gas, so that there is no ignition of the gas. (For example, refer to Patent Document 1).

In addition, the conventional varistor element is housed in a hollow case made of a non-combustible material and sealed. It is shown that the apparatus does not ignite and a great damage is prevented (for example, refer to Patent Document 2).
JP 2002-364970 A Japanese Utility Model Publication No. Hei 6-31102

  When HC refrigerant is used in a refrigerator of the type in which the electronic board is placed in the control box board storage part, which is a plastic part on the back wall of the cabinet, if a gas leak occurs due to a broken pipe of the cooler, etc. There is a risk that the gas may enter, and the gas may also enter the substrate storage portion of the control box. If a spark occurs due to the destruction of the varistor element caused by the application of an abnormal voltage simultaneously with the gas intrusion, fire in the cabinet due to ignition / explosion due to sparking to the leaked gas or ignition of other electronic components, etc. There is a risk to reach.

  In Patent Document 1, a compressor is installed in a machine room at the lower back of a refrigerator, and an evaporating dish for receiving defrosted water from a cooler from a drain outlet is installed above the compressor. The evaporating dish evaporates the machine room space. It is characterized by being divided into a drain outlet side at the top of the dish and a side having electrical contacts such as a compressor at the bottom. Assuming that the HC refrigerant is heavier than air and that the HC refrigerant leaked from the inside of the cabinet leaks only from the drain into the machine room outside the warehouse, the gas is stored inside the evaporating dish. This is a measure that the electrical contacts of the lower compressor and the like are not filled with leaked gas and the HC refrigerant does not exceed the lower combustion limit concentration by escaping outward from the upper opening. Therefore, in the type in which the electronic board is placed in the board storage part of the control box on the back wall of the refrigerator, which is located in the center to the upper side of the refrigerator cabinet and has a structure in which the intrusion port of the leaked gas cannot be specified, the inside of the control box As a countermeasure against ignition of HC refrigerant due to spark of the varistor element, there was a problem that this countermeasure could not be implemented.

  Furthermore, since the varistor element housed in the hollow case made of non-combustible material in Patent Document 2 has a sealed structure inside the hollow case made of non-combustible material, the cost of the varistor element with case itself is high. It is. It is necessary to use a low-cost varistor element in order to make the varistor element common with models that do not use HC refrigerant, and the problem that the varistor element housed in this incombustible material case cannot be used. There was a point.

  The present invention has been made to solve the above-described problems, and the HC refrigerant gas leaks into the refrigerator with respect to the refrigerator in which the electronic substrate is installed in the substrate storage portion in the control box in the refrigerator. If a varistor element breaks down due to the application of abnormal voltage at the same time when a leak occurs in the control box, which is the rear wall of the cabinet, and sparks are generated, the spark ignites the gas leaked into the cabinet. The purpose is to obtain a safe refrigerator that does not explode at low cost.

  The refrigerator according to the present invention includes a refrigerator main body having a refrigerator compartment and the like, a cooler that generates cool air to be supplied into the refrigerator, a refrigerant circuit that uses a combustible refrigerant as a refrigerant, and heat generation with respect to application of abnormal voltage. A control electronic board having a varistor that has the property of protecting other electronic parts by being destroyed, a control box provided on the back of the refrigerator compartment and containing a board storage part for storing the electronic board, and an electronic varistor. A varistor storage portion that surrounds the substrate and has a varistor space having a substantially sealed structure, and a sealing member that covers an opening of the substrate storage portion are provided.

In the refrigerator of the present invention, since the varistor has a substantially double sealed structure due to the above-described configuration, the varistor leaks into the cabinet due to breakage of a pipe such as a cooler, and at the same time, the varistor is caused by application of abnormal voltage or the like. Even if it breaks and sparks, there is no ignition in the outside substrate housing portion even if there is combustion in the varistor housing portion.
Further, the substrate storage portion is also surrounded by a wall and a sealing member, and there is an effect that ignition, explosion, or the like does not occur in the refrigerator.

Embodiment 1 FIG.
1 to 13 are diagrams showing Embodiment 1, FIG. 1 is a front view of a refrigerator, FIG. 2 is a longitudinal sectional view of the refrigerator, FIG. 3 is a refrigerant circuit diagram of the refrigerator, and FIG. 4 is an enlarged view of the vicinity of the cooler. FIG. 5, FIG. 5 is a diagram comparing the characteristics of a hydrocarbon-based refrigerant and the present CFC, FIG. 6 is a perspective view of the control box viewed from the front side, FIG. 7 is a perspective view of the control box viewed from the back side, and FIG. 7 is a perspective view with the nonflammable tape and duct removed, FIG. 9 is a sectional view taken along the line ZZ in FIG. 8, FIG. 10 is a perspective view with the substrate removed from FIG. 8, FIG. FIG. 13 is a circuit diagram showing the current-voltage characteristics of the varistor, and FIG. 13 is a circuit diagram in the vicinity of the varistor on the substrate.

  As shown in FIGS. 1 and 2, the refrigerator main body 1 is divided into two upper and lower chambers having a freezer compartment 2 on the top and a refrigerator compartment 3 on the bottom, and the temperature at the top of the refrigerator compartment 3 is higher than that of the ordinary refrigerator compartment 3. This is a refrigerator with a low chilled chamber 4. On the back side of the chilled chamber 4, a control box 5, which is a back wall inside the plastic part storage, is installed.

  As shown in FIG. 3, the refrigerant circuit of the refrigerator has a compressor 14 for compressing the refrigerant, a cabinet pipe 15 that acts as a condenser for liquefying the high-temperature and high-pressure refrigerant gas, a dryer 16, and a liquefied refrigerant by reducing the pressure. A capillary tube 17 serving as a phase refrigerant, a cooler 18 for exchanging heat with the air in the cabinet, a suction pipe 19 and a muffler 20 are sequentially connected.

  As shown in FIG. 4, the cooler 18 is connected to the U pipe connecting the pipe by welding. Further, there are welded portions around the muffler 20, and these may be damaged for some reason.

  Moreover, the refrigerant | coolant uses the hydrocarbon refrigerant | coolant isobutane (HC refrigerant | coolant R600a) which is 1 type of a combustible refrigerant | coolant. FIG. 5 shows the characteristics of the current Freon (HFC134a) and R600a. R600a has been adopted since the 1990s in Europe where the natural air convection system is the mainstream, and is widely used mainly in northern Europe. In contrast to the cold natural convection method, a refrigerator that uses a cold forced forced circulation method that requires a heater for defrosting and a fan motor for circulating cold, which is common in Japan, requires construction of technology for safety.

  As shown in FIGS. 6 to 8, a styrene-made duct 9 for sending cold air from the freezer compartment 2 to the refrigerator compartment 3 is attached to the back of the control box 5, and the cold air enters the duct 9 from the suction port 9 a of the duct 9. The cooling air enters and is sent from the cold air outlet 5a of the control box 5 to the chilled chamber 4 and the remaining cold air is distributed from the outlets 5b to 5d to the refrigerator compartment 3.

  In addition, the control box 5 has a substrate storage portion 7 surrounded by a rib, and stores an electronic substrate 10 therein. Further, the electronic substrate 10 is substantially sealed with a flame retardant tape 8 (sealing member) so as to cover the electronic substrate 10 and the opening of the substrate storage portion 7 so as not to come into contact with outside air. The electronic board 10 generates heat, and if it comes into contact with low outside air in the refrigerator, there is a risk of dew formation and short-circuiting, and it may ignite due to a failure of the board. It is the structure which is substantially sealed with the flame-retardant tape 8 so that the opening part may be covered.

  The temperature adjustment dial 6 is attached to the electronic substrate 10 attached to the substrate storage portion 7 so as to sandwich the surface of the control box 5. Since the substrate storage portion 7 has such a configuration, it is difficult to completely seal the flame-resistant tape 8 by attaching the temperature adjusting dial 6. It may invade.

  As shown in FIGS. 8 and 10, the electronic substrate 10 is attached to the substrate storage portion 7 by the electronic substrate fixing claws 7 a and the electronic substrate fixing ribs 7 b of the substrate storage portion 7. There is a risk that an abnormal voltage may be applied to the electronic board 10 due to a difference in voltage between countries, a country with poor power conditions, a lightning strike, or the like. For the purpose of protecting the electronic substrate 10 so as not to perform a costly service of replacing the substrate, the electronic substrate 10 of the refrigerator generates heat or breaks down due to abnormal voltage application or lightning surge intrusion and other electronic components A part called a varistor 11 having the characteristic of protecting the surface is attached (FIG. 9). This is because only the varistor 11 is destroyed in response to a lightning surge, so that it can be easily repaired if the varistor 11 is replaced.

An example of the configuration of the varistor 11 is shown in FIG. An example of the current-voltage characteristics of the varistor 11 is shown in FIG. Further, a circuit of the varistor 11 portion on the electronic substrate 10 is shown in FIG.
The varistor is an abbreviation for “voltage variable resister” (meaning that the resistance value changes with voltage). Some semiconductors and electronic ceramics have the property that the resistance value changes nonlinearly depending on the applied voltage.For example, a high resistance value is exhibited up to a certain voltage, and the resistance value suddenly decreases when the voltage is exceeded. Apply current. A varistor is an element utilizing this property. Electronic ceramics are polycrystalline bodies in which a large number of fine crystal grains are aggregated, and ceramics mainly composed of zinc oxide are frequently used in varistors. The grain boundary surrounding the crystal grains is a high-resistance insulating layer, and current does not flow up to a certain voltage, but when that voltage is exceeded, a large current flows due to the quantum mechanical tunnel effect. Therefore, when an abnormal voltage is applied from the AC power source 21, a large current flows through the varistor 11, the fuse 22 is cut, and no voltage is applied to the circuits after the varistor 11. Therefore, other components can be protected. .

  As shown in FIGS. 9 and 10, there is a varistor storage rib 12 (varistor storage portion) that surrounds and surrounds the varistor 11 in the substrate storage portion 7. The varistor storage rib 12 and the electronic substrate 10 store the varistor storage rib 12. The varistor 11 has a substantially sealed structure. That is, the electronic board 10 with the varistor 11 is installed in the board storage part 7 surrounded by the control box 5 which is the back wall in the refrigerator, and the varistor 11 is enclosed and stored inside the board storage part 7 of the control box 5. Since the varistor housing rib 12 is formed and the electronic substrate 10 and the opening of the substrate housing portion 7 are substantially sealed with the flame retardant tape 8, the varistor 11 has a substantially sealed structure. The configuration is a substantially double structure.

  Further, as shown in FIG. 10, in the substrate storage portion 7, the varistor storage rib 12 for storing the varistor 11 is located above the temperature adjustment dial mounting portion 13. Therefore, even if the HC refrigerant enters the substrate storage portion 7 from the temperature adjustment dial attachment portion 13, the HC refrigerant goes down because it is heavier than air, so the varistor storage rib 12 that stores the varistor 11 at the top. It is difficult for HC refrigerant to enter inside, and the explosion concentration does not occur.

Next, the operation will be described.
As described above, the inside of the substrate storage portion 7 having a substantially sealed structure composed of the varistor storage rib 12 and the flame retardant tape 8, but the cold inside the cabinet is caused by human actions such as replacement of the temperature adjustment dial 6 at the service. Since it may be in a state where it can easily enter, if the HC refrigerant leaks into the cabinet due to pipe breakage of the cooler 18 or the like in the cabinet, it will continuously enter the substrate storage unit 7. Then, as time passes, the HC refrigerant may be filled in the substrate storage portion 7 and the combustion concentration of the HC refrigerant may be reached. At the same time, the varistor 11 may be destroyed due to application of an abnormal voltage or the like, and a spark may occur. Since the varistor 11 is housed by the varistor housing rib 12 housed in the substrate housing portion 7 and the electronic substrate 10 and is located above the temperature adjustment dial mounting portion 13, the combustion in the varistor housing rib 12 is first performed. Does not happen. Even if combustion occurs in the varistor housing rib 12, the combustion does not ignite the electronic board housing portion 7 outside the varistor housing rib 12. Furthermore, it has a substantially double structure, and there is little risk of ignition or explosion in the refrigerator compartment 3 having a substantially sealed structure.

  HC refrigerant ignites gas at a concentration of 1.85 to 8.5% and a theoretical ignition temperature of 494 ° C (standard value is 394 ° C), but the open area and passage length leading to the next room and gas combustion Whether or not the adjacent chamber can be ignited is determined by the influence of the ejection speed (determined by the amount of oxygen in the closed space, the absolute amount of gas, etc.), so if the varistor 11 is surrounded by the rib 12 for varistor storage, it is refrigerated. There is no ignition to chamber 3.

  As described above, in a refrigerator using a flammable refrigerant (R600a) as a refrigerant, a varistor 11 having a characteristic that protects other electronic components by generating heat and breaking against application of abnormal voltage is connected. Since the electronic substrate 10 is a refrigerator in which the electronic substrate 10 is housed in a substrate housing portion 7 formed in a control box 5 which is a back wall in the cabinet and is substantially sealed with a flame retardant tape 8, a caster is used when the substrate is defective. Even in a small refrigerator without a substrate, it is possible to easily replace the substrate on the front side without going around the back.

  In addition, since the varistor 11 is attached to the electronic substrate 10, when an abnormal voltage is applied from the power cord and enters while the refrigerator is operating, the varistor 11 generates heat and breaks down to protect other electronic components. If only the broken varistor 11 is replaced, it can be easily repaired, and it is possible to repair without performing a costly service of replacing the substrate.

  Further, since the varistor storage rib 12 surrounding the varistor 11 is integrally formed in the substrate storage portion 7 in the control box 5, the varistor 11 has a substantially sealed structure by the varistor storage rib 12 and the electronic substrate 10. In addition, since the electronic substrate 10 and the opening of the substrate housing portion 7 are substantially sealed with the flame retardant tape 8, the varistor 11 has a substantially double sealed structure. Even if flammable refrigerant gas leaks into the cabinet due to broken pipes of the cooler 18 or the like, and the varistor 11 breaks down due to the application of abnormal voltage or the like and sparks at the same time, the area around the varistor 11 is the first inside the control box 5. Since the varistor storage rib 12 and the substrate itself are closed, the space is isolated from the other substrate storage portions 7 in the control box 5, so there is no combustion in the first partition wall. However, there is no ignition in the substrate storage part 7 outside the partition wall.

  Further, the substrate storage portion 7 is also surrounded by a wall and a flame retardant tape 8 and is a second partition wall from the varistor 11, so that ignition in the refrigerator cabinet outside the substrate storage portion is performed.・ Has an effect that no explosion occurs.

  As described above, since the varistor housing rib 12 is simply provided in the substrate housing portion 7 inside the control box 5, there is an advantage that an easy mold production of the control box 5 can be executed at low cost.

  In addition, when the HFC134a refrigerant refrigerator is used as the HC refrigerant refrigerator, the substrate storage unit 7 inside the control box 5 which is the rear wall of the refrigerator also in the HFC134a refrigerant refrigerator has a substrate exposed to low outside air in the refrigerator. In order to prevent ignition due to a short circuit from the beginning or ignition due to failure of the substrate, the substrate and the substrate storage portion opening are sealed with the flame retardant tape 8 so as to have a substantially sealed structure. That is, since the configuration can be made only by changing the varistor housing rib 12 in the substrate housing section 7 inside the control box 5, it has an effect that it can be executed at low cost and in a short period of time by easy mold modification.

In addition, the refrigerant is a refrigerator that uses hydrocarbon refrigerant isobutane (R600a HC refrigerant), which is the mainstream of non-fluorocarbon refrigerants among flammable refrigerants. It is an excellent cooling source with a conversion factor of 3 or less (relative value when carbon dioxide (CO ₂ ) is 1), and a non-fluorocarbon refrigerator friendly to the global environment can be obtained at low cost.

  In addition, since the storage portion surrounding the varistor 11 is formed in the substrate storage portion 7 above the temperature adjustment dial mounting portion 13 through which air in the cabinet can enter from the front, the varistor 11 in the substrate storage portion 7 is formed. The rib 12 for storing the varistor is located above the temperature adjustment dial mounting portion 13, and even if HC refrigerant enters the substrate storage portion 7 from the temperature adjustment dial mounting portion 13, the HC refrigerant is heavier than air. Therefore, the HC refrigerant hardly penetrates into the varistor housing rib 12 for housing the varistor 11 on the upper side, so that the explosion concentration does not occur.

It is a figure which shows Embodiment 1 and is a front view in the refrigerator compartment. It is a figure which shows Embodiment 1 and is a longitudinal cross-sectional view of a refrigerator. It is a figure which shows Embodiment 1, and is a refrigerant circuit figure of a refrigerator. It is a figure which shows Embodiment 1, and is an enlarged view of a cooler vicinity. It is a figure which shows Embodiment 1, and is the figure which compared the characteristic of the hydrocarbon-type refrigerant | coolant and the present CFC. It is a figure which shows Embodiment 1, and is the perspective view which looked at the control box from the front side. It is a figure which shows Embodiment 1, and is the perspective view which looked at the control box from the back side. It is a figure which shows Embodiment 1, and is the perspective view which removed the nonflammable tape and the duct from FIG. It is a figure which shows Embodiment 1, and is ZZ sectional drawing of FIG. FIG. 9 shows the first embodiment, and is a perspective view with the substrate removed from FIG. 8. FIG. 5 shows the first embodiment and is a structural diagram of a varistor. It is a figure which shows Embodiment 1 and is a figure which shows the current-voltage characteristic of a varistor. FIG. 5 shows the first embodiment, and is a circuit diagram in the vicinity of a varistor on a substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Refrigerator main body, 2 Freezing room, 3 Refrigeration room, 4 Chilled room, 5 Control box, 5a-5d Cold air outlet, 6 Temperature adjustment dial, 7 Board storage part, 7a Electronic board fixing nail, 7b Electronic board fixing rib , 8 Flame retardant tape, 9 Duct, 9a Suction port, 10 Electronic board, 11 Varistor, 11a Insulating coating, 11b Electrode, 11c Varistor element, 11d Lead wire, 12 Varistor housing rib, 13 Temperature adjustment dial mounting part, 14 Compressor, 15 cabinet pipe, 16 dryer, 17 capillary tube, 18 cooler, 19 suction pipe, 20 muffler.

Claims (4)

A refrigerator body having a refrigerator compartment,
A refrigerant circuit including a cooler that generates cool air to be supplied into the refrigerator, and using a combustible refrigerant as a refrigerant;
An electronic board for control equipped with a varistor having the characteristic of protecting other electronic components by generating heat and breaking against application of abnormal voltage;
A control box provided on the back of the refrigeration chamber and having a substrate storage unit for storing the electronic substrate;
A varistor housing portion that surrounds the varistor together with the electronic substrate and has a substantially sealed structure in the space of the varistor;
A refrigerator comprising: a sealing member that covers an opening of the substrate storage unit.   The refrigerator according to claim 1, wherein a varistor storage portion surrounding the varistor element is integrally formed in the substrate storage portion.   The refrigerator according to claim 1, wherein the combustible refrigerant uses a hydrocarbon-based refrigerant.   The control box is attached to the electronic board, has a temperature adjustment dial attachment part for adjusting the temperature in the cabinet, and the varistor storage part is positioned above the temperature adjustment dial attachment part. The refrigerator according to claim 1.

Images