JPH0253707B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a defrosting control device for a refrigerator or the like. FIG. 1 shows a defrosting control device for fan-type refrigerators currently in common use. The internal temperature adjustment switch SW ₁ is a thermo switch that detects the temperature inside the refrigerator, and the cooling compressor CP is connected to an AC power supply.
The refrigerator cools the inside of the refrigerator by being supplied with electricity from the AC through the movable contacts a and the normally closed fixed contacts b of the internal temperature adjustment switch SW ₁ and timer switch SW ₂ . The timer motor TM and the timer switch SW ₂ constitute a timer, and the timer motor TM rotates a cam by being energized from an AC power source via the refrigerator temperature adjustment switch SW ₁ , and the timer switch is activated by this cam. The movable contact piece a of SW ₂ is driven at predetermined intervals. When the timer switch SW ₂ is off and the defrosting heater H is energized from the AC power supply via the refrigerator temperature adjustment switch SW ₁ and the timer motor TM, the defrosting heater H substantially performs the defrosting operation by the impedance of the timer motor TM. do not have. When the timer switch SW ₂ is turned on and its movable contact a is connected to the normally open fixed contact C, the defrosting heater H is switched from the AC power supply AC to the internal temperature adjustment switch SW ₁ and the timer switch.
When energized through SW ₂ and switch SW ₃ , it generates heat and defrosts the compressor CP, etc.
Switch SW ₃ is a bimetal thermoswitch that detects the temperature inside the refrigerator and turns on when it is below a predetermined temperature. However, in this defrosting control device, the timer motor
Since the TM is energized via the chamber temperature adjustment switch SW ₁ , the defrosting cycle is controlled by the integration of the timer period and the ON time of the chamber temperature adjustment switch SW ₁ , that is, <timer period> ÷ < Onpercement (timer operation rate) of chamber temperature adjustment switch SW ₁ >. For this reason, the defrosting cycle in the four seasons is as follows.

[Table] Also, the amount of frost is different in summer and winter. In other words, in the summer when the refrigerator door is opened and closed a lot and there is a lot of moisture in the outside air, frost tends to form, and the opposite is true in the winter. Therefore, the defrosting cycle is becoming shorter in summer,
Because the amount of frost buildup is large, it is difficult to remove the frost, and the defrosting cycle is longer in winter, but because the amount of frost buildup is small, defrosting is often performed even when there is no frost, resulting in wasted energy and low reliability. In order to compensate for this drawback, a method is currently being used in which the timer cycle is varied in multiple stages depending on the outside temperature. However, in this method, the timer cycle is changed in multiple stages depending on the outside temperature, resulting in a significant increase in cost. An object of the present invention is to improve the above-mentioned drawbacks and provide a defrosting control device that is inexpensive and highly reliable. The present invention will be described below by way of examples with reference to the drawings. FIG. 2 shows an embodiment of the invention. This embodiment uses a temperature-sensitive switch consisting of a bimetallic thermoswitch in the defrosting control device described above.
SW ₄ is provided, and a switch SW ₅ is added to the timer so that when the timer switches the power supply to the defrosting heater, the defrosting switch is turned on. The temperature-sensitive switch SW ₄ is composed of a bimetal thermoswitch or the like that detects the outside air temperature outside the refrigerator, and when the outside air temperature exceeds a set temperature, the movable contact piece d switches from the fixed contact e to the fixed contact f. If the outside temperature is below the set temperature, the temperature-sensitive switch SW ₄
is turned off, and the timer motor TM is energized via the chamber temperature adjustment switch SW ₁ as before. When the outside temperature reaches or exceeds the set temperature, the temperature-sensitive switch SW ₄ is turned on, and the timer motor TM is energized without going through the internal temperature adjustment switch SW ₁ , thereby shortening the defrosting cycle. Now, if the temperature setting of temperature-sensitive switch SW ₄ is set to 20℃ and the timer cycle is set to 11H, the defrosting cycle will be as follows.

[Table] Therefore, in the winter, it is possible to save energy by not having to defrost even when there is no frost, and in the summer, the defrost cycle is shortened, making it possible to defrost reliably. , defrosting can be performed efficiently and reliability can be improved. Temperature sensitive switch SW ₄
The current flowing through the temperature-sensitive switch is more than ten mA.
SW ₄ can be an inexpensive bimetal thermoswitch. Even if temperature-sensitive switch SW ₄ is switched during defrosting, there is no effect at all, and there is no need to provide a self-holding circuit or a guarantee circuit relay. If switch SW ₅ is not present, when timer switch SW ₂ is turned on while temperature-sensitive switch SW ₄ is turned on, defrosting heater H is not energized when refrigerator temperature adjustment switch SW ₁ is turned off, and therefore defrosting is not possible. There is a problem in that the movable contact a of the timer switch SW moves to the fixed contact b side after a predetermined period of time even though this is not done. Defrost switch SW ₅ is provided to solve this problem _.
As seen in the time chart of FIG. 3, the switch is turned on slightly earlier than the timer switch _SW2 is turned on, and turned off slightly later than the timer switch _SW2 is turned off. Therefore, when the timer switches energization to the defrosting switch, the defrosting switch is on. FIG. 4 shows part of the timer. The cams 1 and 2 are rotationally driven by a timer motor TM, and the contacts a, b, and c are connected to conductive contact plates 3a and 3.
b, 3c. The contact plates 3a and 3c are driven by the protrusions of the cams 1 and 2, so that only when the cams 1 and 2 rotate by α per rotation, the contacts a and c come into contact and the contacts a and b separate, and the other Sometimes, contacts a and c are separated and contacts a and b are in contact. Further, the switch SW ₅ consists of conductive contact plates 4g and 4h having contacts g and h, and the cams 5 and 6 are rotationally driven by a timer motor TM. Contact plate 4
As g and 4h are driven by the protrusions of cams 5 and 6, the contact points g and h change to α per rotation as shown in Fig. 3.
It contacts only when it rotates by +2β, that is, it turns on β minutes earlier than timer switch SW ₂ turns on and turns off β minutes later than timer switch SW ₂ turns off. As described above, according to the present invention, depending on whether the temperature outside the refrigerator is below a predetermined temperature, the temperature-sensitive switch selects whether or not to apply electricity to the timer via the temperature adjustment switch inside the refrigerator. Therefore, defrosting can be reliably performed even when the temperature outside the refrigerator is high, and energy saving can be achieved without unnecessary defrosting even when the temperature outside the refrigerator is low. Therefore, defrosting can be performed efficiently and reliability can be improved. In addition, the circuit is simple and requires fewer parts, making it cheaper. In addition, I connected a defrost switch in parallel with the internal temperature adjustment switch and set it so that when the timer switched the power to the defrost heater, the defrost switch was on, so the timer was set to turn on the defrost heater. When switching the power to the heater,
Even if the internal temperature adjustment switch is turned off, the defrosting switch is still on, so the defrosting heater can operate, and there is no problem where the defrosting heater cannot operate due to the internal temperature adjustment switch being turned off. It is possible to perform reliable defrosting, improve defrosting efficiency, and improve the reliability of the refrigerator.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional defrosting control device, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a timing chart of the embodiment, and Fig. 4 is a timer in the embodiment. It is a top view showing a part of. SW ₄ ...Temperature-sensitive switch.

Claims (1)

[Claims] 1. In a defrosting control device that uses a timer to switch and control energization to a cooling compressor and a defrosting heater, the energization of which is controlled by an internal temperature adjustment switch, a temperature-sensitive switch that detects the external temperature; A defrosting switch is connected in parallel with the temperature control switch inside the refrigerator, and the temperature sensing switch controls whether or not the timer is energized depending on whether the temperature outside the refrigerator is below a predetermined temperature. The defrosting is characterized in that a selection is made as to whether or not to use an internal temperature adjustment switch, and the defrosting switch is set to be turned on when the timer switches energization to the defrosting heater. Control device.