JP2013088070A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator having a circuit configuration with enhanced reliability.SOLUTION: The refrigerator includes a cooler 2 for cooling a chamber of the refrigerator, a defrosting heater 4 for defrosting frost attached to the cooler 2, a temperature fuse 3 for preventing a temperature of the defrosting heater 4 from rising, a switching element 19 for exerting on-off control to energization of the defrosting heater 4, and a power plug 13 for supplying power to the defrosting heater 4. The refrigerator is equipped with a circuit wherein the defrosting heater 4 and switching element 19 are serially connected in any order to the side of a live line 13a of the power plug and further serially connected to the side of a neutral line 13b via the temperature fuse 3.

Description

  The present invention relates to a refrigerator.

  As a background art in this technical field, there is JP-A-07-085757 (Patent Document 1). In Patent Document 1, for example, a temperature sensing element, a lead wire connected to both ends of the temperature sensing element, one end side is sealed, the temperature sensing element is built in, and the lead wire is taken out to the outside. A sealed resin tube and a support tube made of a member with good thermal conductivity attached to the main body side of the heat exchanger; and an end portion on the side of taking out the lead wire of the resin tube to the outside A temperature detector for a heat exchanger is described in which the support tube and the resin tube are fixed by caulking the support tube slightly from the corresponding end portion of the support tube.

Japanese Patent Laid-Open No. 07-085757

  In Patent Document 1, a defrosting heater is provided to remove frost adhering to the heat exchanger, and a thermal fuse element is used as a temperature sensitive element in order to prevent an abnormal rise in heater temperature. It is located near the exchanger. However, since no insulation protection means is provided on the circuit, the reliability is lowered when insulation between the thermal fuse and the outside cannot be maintained. For example, if the resin tube provided as the insulation protection for the thermal fuse element is penetrated during operation, or if the resin tube is perforated for some reason in the process, Insulation between the fuse element and the external heat exchanger having electrical conductivity cannot be maintained, and leakage current (leakage) is generated from the thermal fuse element through the heat exchanger. If a defrosting heater is arranged in series with the temperature fuse element, the heater may be energized at all times due to leakage current.

  Then, an object of this invention is to provide the refrigerator provided with the circuit structure with improved reliability.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-mentioned problems. For example, a cooler for cooling the inside of the refrigerator, a defrosting heater for melting frost attached to the cooler, and the removal A temperature sensing element for preventing temperature rise of the frost heater, a switching element for turning on / off the energization to the defrost heater, and a power plug for supplying power to the defrost heater. The defrosting heater and the switching element are connected in series in an unspecified permutation to the live side of the power plug, and further connected in series to the neutral side of the power plug via a temperature sensing element.

  ADVANTAGE OF THE INVENTION According to this invention, the refrigerator provided with the circuit structure with improved reliability can be provided.

1 is an isometric view of a refrigerator according to an embodiment of the present invention. It is sectional drawing of the refrigerator of FIG. It is an internal block diagram of a thermal fuse. It is a block diagram of the control system of the refrigerator of FIG. It is a flowchart which shows the control operation of the heater for defrost in the control system of FIG. It is a block diagram of the control system of the refrigerator of 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.

(First embodiment)
The refrigerator of 1st embodiment of this invention is demonstrated below using FIGS.

  First, the outline | summary of the refrigerator of this embodiment is demonstrated. FIG. 1 is an isometric view of the refrigerator of the present embodiment, and FIG. 2 is a sectional view of the refrigerator.

  The refrigerator 50 includes a refrigerator body 51, storage chamber doors 52 to 56, a refrigeration cycle, a control system, and the like. The refrigerator main body 51 is configured to include a flammable urethane foam heat insulating material 63 and a vacuum heat insulating material (not shown) between a steel plate outer box 61 and a resin inner box 62, and the refrigerator compartment from above. 72, an ice making chamber 73, a quick freezing chamber 74, a freezing chamber 75, and a vegetable chamber 76 in this order. The refrigerated room 72 and the vegetable room 76 are storage rooms in a refrigerated temperature zone, and the ice making room 73, the quick freezing room 74, and the freezing room 75 have a freezing temperature zone of 0 ° C. or lower (for example, about −20 ° C. to −18 ° C. Temperature room).

  On the front surface of the refrigerator main body 51, storage chamber doors 52 to 56 that open and close front opening portions of the storage chambers 72 to 76 are provided. The refrigerator compartment door 52 opens and closes the front opening of the refrigerator compartment 72, the ice making door 53 opens and closes the front opening of the ice making chamber 73, and the quick freezing compartment door 54 opens and closes the front opening of the quick freezing compartment 74. The freezing room door 55 is a door that opens and closes the front opening of the freezing room 75, and the vegetable room door 56 is a door that opens and closes the front opening of the vegetable room 76. The refrigerator compartment door 52 is constituted by a double door with double doors, and the other doors 53 to 56 are constituted by drawer type doors.

  A display unit 30 including a display lamp and a liquid crystal panel is provided in front of the refrigerator compartment door 52. The defrosting heater 4 is installed on the urethane foam heat insulating material side of the inner box 62 where the freezing chamber 75 is formed, the cooler 2 on the upper side, and the thermal fuse 3 (temperature sensing element) on the inner box side of the cooler 2. The flammable urethane foam heat insulating material 63 exists around. On the ceiling surface of the refrigerator main body, a control board 1 that performs operation control of the compressor 5 of the refrigerator and temperature control inside the refrigerator is installed. The control board 1 is mounted with a heater driving element that controls on / off of the defrosting heater.

  The thermal fuse 3 will be described with reference to the internal configuration diagram of the thermal fuse of FIG. In the figure, the thermal fuse 3 constitutes an internal element 11 with a thermal fuse element 6 that is cut by heat generation due to overcurrent, and connection elements 7 and 8 that are connected by lead wires 9 and 10 covered with the thermal fuse element 6. The internal element 11 is inserted into a transparent tube 12 having a predetermined length opened at both ends, and heat welding is performed on both ends of the tube 12 by a high frequency welder. Thereby, the tube 12 is sealed by the high frequency welder, and the welder portions 12a and 12b are formed.

  Next, the configuration of the control system of the refrigerator of this embodiment will be described with reference to FIG. FIG. 4 is a configuration diagram of a control system of the refrigerator of FIG.

  The refrigerator control system includes a power supply flag 13, a filter circuit 14, a converter circuit 15, and a switching power supply circuit 18. Although an inverter circuit and a compressor are connected to the output side of the converter circuit 15, they are omitted in FIG.

  The filter circuit 14 filters the AC voltage supplied from the 100 V power supply flag 13 and outputs the filtered AC voltage to the converter circuit 15. The converter circuit 15 includes a rectifier circuit 16 that rectifies the filtered AC voltage and converts it to a DC voltage, and a smoothing circuit 17 that smoothes the DC voltage converted by the rectifier circuit 16.

  The switching power supply circuit 18 is applied with the DC voltage generated by the converter circuit 15 on the primary side, generates a DC voltage lower than the DC voltage as a control power supply, and outputs it to the secondary side. The switching power supply circuit 18 generates a plurality of types of DC voltages, for example, 12V and 5V as internal power supplies and 15V and 5V as inverter power supplies and outputs them to the secondary side. Only the output of a DC voltage of 5V to the secondary side is shown.

  The defrosting heater 4 is connected after the output of the filter circuit 14, and the defrosting heater 4 is connected to the live line 13 a side of the power supply, and then in the permutation on the switching element 19, the thermal fuse 3, and the neutral line 13 b side. It is configured by series connection. The defrosting heater 4 and the switching element 19 permutation may be interchanged.

  The thermal fuse 3 is fixed to the cooler 2 and has a close contact structure (not shown) in order to accurately measure the temperature state of the cooler 2. The cooler itself is connected to the ground.

  The switching element 19 is connected to turn on / off the energization to the defrosting heater 4, and the drive command signal is output from the control device 20. The control device 20 includes a drive circuit 21 and a microcomputer 22.

  Next, the control operation of the defrosting heater 4 will be described with reference to FIG. FIG. 5 is a flowchart showing the control operation of the defrosting heater 4 in the control device 20 of FIG.

  The temperature of the cooler 2 is detected by the cooler temperature sensor (step S1), and it is determined whether the detected temperature is 8 ° C. or higher (step S2). If it is determined in this determination that the detected temperature is 8 ° C. or higher, the defrosting heater 4 is turned off (step S3), the process returns to step S1, and the determination in step S2 is repeated.

  If it is determined in step S2 that the temperature is less than 8 ° C., an energization command signal for turning on the defrosting heater 4 is output (step S4), and the switching element 19 is controlled to be turned on / off via the drive circuit 21. Then, the defrosting heater 4 is energized (step S5). At that time, a timer provided in the microcomputer 22 is activated to integrate the energization time of the defrosting heater 4 (step S6). If this accumulated energization time is within the predetermined value, the process returns to step S2, and steps S2 to S7 are repeated until the temperature of the cooler 2 reaches 8 ° C. or higher, and energization to the defrosting heater 4 is turned on.

  If the cumulative energization time of the defrosting heater 4 exceeds the predetermined value in the determination in step S7, the energization to the defrosting heater 4 is turned off (step S8), and the heater abnormality is indicated on the display unit of the refrigerator 50. Display is performed by blinking or lighting 30 (step S9). Thereby, disconnection of the defrosting heater 4 and the like can be easily confirmed. In addition, this display part 30 may be installed not only in the storeroom door of the refrigerator 50 but in a store | warehouse | chamber.

  In the conventional circuit specification, when a problem occurs in which the connection elements 7 and 8 which are non-insulating portions of the thermal fuse 3 are exposed from the tube 12 of the thermal fuse 3, the ground is passed through the cooler 2 that is closely fixed. When the leak current flows, the circuit is short-circuited, and the defrosting heater 4 may be always energized.

  On the other hand, according to the present embodiment, even when a leakage current flows from the thermal fuse 3, the switching element 19 that is turned on / off by the drive command signal from the control device 20 between the defrosting heater 4 and the thermal fuse 3. Therefore, even when the defrosting heater 4 is always energized, the temperature of the cooler 2 is detected from the control operation of the defrosting heater 4, and if the detected temperature is 8 ° C. or higher, the heater is turned off. It becomes the specification to turn off. This can improve the reliability of the product. In addition, by designating parts to be connected to the live line 13a and the neutral line 13b of the power flag 13, it becomes a form that complies with the specification in the safety standard.

In the present embodiment, the defrosting heater 4 is connected to the live line 13a side of the power source, and then the circuit is configured by serial connection in the permutation of the switching element 19, the thermal fuse 3, and the neutral line 13b side. That is, a cooler for cooling the inside of the refrigerator, a defrosting heater for melting frost attached to the cooler, a temperature sensing element for preventing a temperature rise of the defrosting heater, and the defrosting A switching element for turning on / off the energization of the heater and a power plug for supplying power to the defrosting heater, and the defrosting heater and the switching element are unspecified on the live side of the power plug The following effects can be obtained by providing a circuit connected in series in a permutation and further connected in series to the neutral side of the power plug via a temperature sensing element.
(1) Even when a leakage current flows from the thermal fuse 3, the heater is always turned off by the normal control operation of the defrosting heater 4, so that the reliability can be easily ensured.
(2) Products that comply with safety standard power terminals can be designed.

(Second embodiment)
Next, the refrigerator of 2nd embodiment of this invention is demonstrated using FIG. FIG. 6 is a block diagram of the control system of the refrigerator of the second embodiment of the present invention. The second embodiment is different from the first embodiment in the following points, and the other points are basically the same as those in the first embodiment, and therefore, redundant description is omitted. To do.

  In the second embodiment, the current fuse 23 is inserted between the power plug 13 and the filter circuit 14 to prevent overcurrent when a leakage current flows from the temperature fuse 3. As a result, it is possible to prevent abnormal leakage current (leakage) and to prevent overcurrent breakdown of relay components. In the figure, the current fuse 23 is inserted into the live line 13a.

1 Control board 2 Cooler 3 Thermal fuse (temperature sensing element)
4 Defroster heater 5 Compressor 6 Thermal fuse element 7, 8 Connection element 9, 10 Lead wire 11 Internal element 12 Tube 12a, 12b Welder part 13 Power supply flag 13a Live line 13b Neutral line 14 Filter circuit 15 Converter circuit 16 Rectification Circuit 17 Smoothing circuit 18 Switching power supply circuit 19 Switching element 20 Controller 21 Drive circuit 22 Microcomputer 23 Current fuse 30 Display unit

Claims (5)

  To a cooler for cooling the inside of the refrigerator, a defrost heater for melting frost attached to the cooler, a temperature sensing element for preventing a temperature rise of the defrost heater, and the defrost heater And a power plug that supplies power to the defrosting heater, and the defrosting heater and the switching element are arranged in an unspecified order to the live side of the power plug. A refrigerator comprising a circuit connected in series and further connected in series to a neutral side of the power plug via a temperature sensitive element.   The refrigerator according to claim 1, wherein the temperature sensitive element is disposed together with the cooler.   The refrigerator according to claim 1, wherein the temperature sensitive element includes a temperature fuse element that is melted by heat generated by overcurrent.   The refrigerator according to claim 1, wherein a switching element is connected in series between the temperature-sensitive element and a neutral side of the power plug.   The refrigerator according to any one of claims 1 to 3, wherein a current fuse element is inserted between the live side and the neutral side of the power plug.