JPH0328304Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention provides a cooler in the ventilation path communicating with the inside of the refrigerator, and supplies cold air from the cooler to the inside of the refrigerator in response to the drive of a blower fan. The present invention relates to a refrigerator that employs a so-called cold air forced circulation system.

[Technical background of the invention and its problems]

For refrigerators that use this type of forced cold air circulation system, it is necessary to prevent the frost buildup on the cooler from exceeding a certain amount, and for this reason conventionally, a defrost command signal is sent every time a certain period of time elapses. A timer is provided to output the defrosting command signal, and the defrosting operation of the cooler is started when the defrosting command signal is output. However, the amount of frost formed on the cooler varies greatly depending on the operating conditions of the refrigerator, and does not necessarily correspond to the elapsed time. If the defrosting operation was controlled using a timer, the defrosting operation may not start even though the amount of frost on the cooler has increased abnormally. There was a problem that I couldn't get it. In addition, in order to deal with such problems, conventionally, a heat-sensitive tube is provided at a certain distance from the cooler, and when the frost on the cooler grows and comes into contact with the heat-sensitive tube, the heat-sensitive tube is It is also possible to detect that frost has reached a certain amount based on temperature changes, and use the detection output to start defrosting operation of the cooler. However, frost on the cooler does not grow uniformly over the entire cooler, so if the conventional configuration described above detects the amount of frost on a localized area of the cooler, it will be difficult to start defrosting operation. There is a risk that timing control may become inaccurate.

[Purpose of invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a refrigerator that can always appropriately control the timing of starting the defrosting operation of the cooler.

[Summary of the idea]

The present invention is a refrigerator that uses a so-called cold air forced circulation system, and when the wind speed sensor that outputs a defrosting start signal and the blower fan are in the operating state when the wind speed in the ventilation path communicating with the inside of the refrigerator is below a set value. A rotation sensor is provided to output a rotation detection signal, and a timer circuit is provided to output a delay signal when a certain period of time has elapsed since the rotation detection signal was output, so that both the defrosting start signal and the delay signal are The above object is achieved by having a configuration in which the defrosting operation of the cooler disposed in the ventilation passage is started when both are output.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a refrigerator body that has a refrigerator compartment 2 and a freezer compartment 3 inside, and in this case, the refrigerator compartment 2 is cooled by a so-called natural circulation method in which cold air from a cooler 4 is circulated by convection. . On the other hand, freezer compartment 3
In this case, a partition plate 6 is provided in which the ventilation passage 5 having an intake port 5a at the bottom of the front side and an exhaust port 5b at the top of the back side extends to the bottom and the back wall of the freezer compartment 3.
A cooler 7 is formed in the ventilation passage 5.
is located. Further, a blower fan 9 driven by a motor 8 is disposed in a portion of the ventilation passage 5 corresponding to the air outlet 5b, and when the blower fan 9 is driven, the air blower fan 9 is driven as shown by arrow A in FIG. Air circulates and cold air from the cooler 7 is supplied into the freezer compartment 3, so that the freezer compartment 3 is cooled by the so-called cold air forced circulation system.
Now, 10 is, for example, a cooler 7 in the ventilation passage 5.
This is a wind speed sensor disposed downstream of the wind speed sensor, which outputs a defrosting start signal _S10 consisting of a high level signal when the detected wind speed is below a set value.

FIG. 2 shows only the parts of the electrical configuration of the refrigerator that are related to the gist of the present invention, and will be described below. That is, reference numeral 11 denotes a rotation sensor for detecting the driving state of the blower fan 9, which detects the rotation by a high level signal when a voltage is applied to the motor 8 (in other words, when the blower fan 9 is in a driving state). Outputs a detection signal _S11 . Reference numeral 12 denotes a defrosting temperature sensor provided in the cooler 7 to detect the completion of defrosting of the cooler 7, which generates a high level signal when the temperature of the cooler 7 reaches a predetermined plus temperature or higher. Outputs defrost completion signal _S12 .
13 is a temperature sensor for the freezer compartment provided to detect the temperature inside the freezer compartment 3, and this outputs a drive signal S ₁₃ consisting of a high level signal when the detected temperature exceeds a predetermined negative temperature. do. 14
is a timer circuit that receives the output of the rotation sensor 11 via the amplifier 15, and this is a timer circuit that receives the rotation detection signal _S14.
The timer operation is started in response to _the input _of A timer signal _S14 is output that causes the high level signal to rise for a period of time (30 seconds), and then a timer signal S that causes the high level signal to rise for a period of time T2 when a certain period of time _T3 (for example, ₂ to 3 hours) has elapsed. ' Outputs ₁₄ . 16 is a defrosting circuit consisting of AND gates 17, 18 and an R-S flip-flop 19; AND gate 17 is connected to both input terminals to receive the outputs of the wind speed sensor 10 and timer circuit 14; Both input terminals are connected to receive the reset output terminal UQ of the R-S flip-flop 19 and the outputs of the freezer temperature sensor 13, and the R-S flip-flop 19 has a set input terminal S that receives the output of the AND gate 17. It is also connected to the reset input terminal R so as to receive the output of the defrosting temperature sensor 12. Note that 20, 21, and 22 are amplifiers that amplify the respective outputs of the wind speed sensor 10, the defrosting temperature sensor 12, and the freezing room temperature sensor 13. 24 is a defrost heater provided in the cooler 7, and this is the R-S in the defrost circuit 16.
When a high level signal is output from the set output terminal Q of the flip-flop 19, the flip-flop 19 is energized and driven through the amplifier 25. Further, 26 is a compressor for the refrigeration cycle, which is energized and driven via an amplifier 27 when a high level signal is output from the AND gate 18 in the defrosting circuit 16.
Although the motor 8 is energized in conjunction with the compressor 26, the power is cut off during the opening period of the freezer compartment door 3a (see Figure 1) regardless of the driving state of the compressor 26. It is becoming more and more common.

Next, the operation of the above configuration will be explained. now,
When a high level signal is output from the AND gate 18 and the compressor 26 and the motor 8 are energized and driven, the blower fan 9 is driven and the arrow A in FIG.
Air is circulated as shown in the figure, and the cooling operation of the freezer compartment 3 is performed. At the same time, the rotation sensor 11 that detects the driving state of the blower fan 9 outputs a rotation detection signal S ₁₁ and the timer circuit 14 starts a timer operation, and when 30 seconds have elapsed after the start of the timer operation, the timer circuit 14 outputs a delayed signal S ₁₄ (high level signal). On the other hand, when the amount of frost on the cooler 7 increases, the ventilation resistance in the ventilation passage 5 increases accordingly, so the wind speed by the ventilation fan 9 in the ventilation passage 5 decreases. When the frost falls below the set value (in other words, when the frost on the cooler 7 exceeds the set amount), the wind speed sensor 10 detects this and outputs a defrosting start signal S ₁₀ (high level signal). Therefore, if the frost on the cooler 7 exceeds the set amount at the time when the delay signal S ₁₄ is output from the timer circuit 14, the defrost start signal S ₁₀ and the delay signal S ₁₄ are sent to both input terminals. A high level signal is output from the received AND gate 17 and the R-S flip-flop 19 is set, so a high level signal is output from the set output terminal Q of the R-S flip-flop 19 and the defrosting heater 24 is energized. At the same time, the reset input terminal Q of the R-S flip-flop 19 and the AND
A low level signal is output from the gate 18, the compressor 26 and the motor 8 are cut off, the cooling operation is stopped, and the defrosting operation of the cooler 7 is started. After that, as the defrosting operation progresses, the frost on the cooler 7 melts, and when the frost on the cooler 7 finally disappears and its temperature rises to a predetermined plus temperature, this is detected. The defrosting temperature sensor 12 outputs a defrosting completion signal _S12 (high level signal)
The defrosting completion signal will be output.
The R-S flip-flop 19 is reset by _S12 . Then, R-S flip-flop 1
The output of the set output terminal 9 is inverted to a low level signal, the defrosting heater 24 is cut off, and the defrosting operation of the cooler 7 is thus terminated. At the same time, the output of the reset output terminal Q of the R-S flip-flop 19 is reversed to a high level signal, and at the end of the defrosting operation, the inside of the freezer compartment 3 is at a predetermined minus temperature or higher. Since the detected temperature sensor 13 for the freezer compartment is outputting the drive signal S ₁₃ (high level signal), the output of the AND gate 18 is also reversed to a high level signal, and as a result, cooling is performed instead of defrosting operation. Driving will begin. When the temperature inside the freezer compartment 3 drops to a predetermined minus temperature due to such cooling operation, the output of the drive signal _S13 from the freezer compartment temperature sensor 13 is stopped, and the compressor 26 and the motor 8 are cut off. It becomes like this. In addition, if the amount of frost on the cooler 7 is less than the set amount at the time when the delay signal _S14 is output from the timer circuit 14 (that is, when the defrost start signal _S10 is not output), the defrosting is started. Although the operation will not start,
After that, when the defrosting start signal _S10 is output, the same defrosting operation as described above is started when the timer circuit 14 outputs the timer signal _S'14 (high level signal).

According to the present embodiment described above, the detection of whether or not the amount of frost on the cooler 7 has exceeded the set amount is carried out based on the wind speed in the ventilation passage 5 (that is, the ventilation resistance of the ventilation passage 5). Therefore, even if the frost on the cooler 7 grows unevenly, this can be reliably detected, and therefore the control of the start time of the defrosting operation can be controlled differently than in the conventional configuration in which frost is detected using a heat-sensitive tube. It never becomes accurate. Furthermore, in this embodiment, the defrosting operation is started based on the presence or absence of the defrosting start signal _S10 after a certain delay time (30 seconds) has elapsed after the blower fan 9 is driven. There is no risk of erroneously starting the defrosting operation when the defrosting start signal _S10 is output from the wind speed sensor 10 that detects a low wind speed state during the period until the ventilation by the fan 9 reaches a steady state. It is. Furthermore, timer circuit 1
4 is configured to output a timer signal S' ₁₄ when 2 to 3 hours have elapsed after the output of the delayed signal S ₁₄ , and the defrosting start signal S ₁₀ at the time when this timer signal S' ₁₀ is output. The defrosting operation is started depending on the presence or absence, and as a result, the defrosting operation of the cooler 7 is reliably performed.

[Effect of idea]

According to the present invention, as is clear from the above description, a cooler is disposed in the ventilation path of the blower fan, and cold air from the cooler is supplied into the refrigerator in accordance with the drive of the blower fan. In the refrigerator, the defrosting operation start timing of the cooler can always be properly controlled, which is a practical advantage.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is a longitudinal cross-sectional side view of the upper half of the refrigerator, Fig. 2 is a wiring diagram showing the electrical configuration, and Fig. 3 shows output waveforms of the rotation sensor and timer circuit. It is a time chart. In the figure, 5 is a ventilation path, 7 is a cooler, 9 is a ventilation fan, 10 is a wind speed sensor, 11 is a rotation sensor, 14
16 represents a timer circuit, 16 represents a defrost circuit, and 24 represents a defrost heater.

Claims (1)

[Scope of utility model registration request] In a refrigerator in which a cooler is disposed in a ventilation passage communicating with the interior of the refrigerator, and cool air from the cooler is supplied to the interior of the refrigerator according to the drive of a blower fan, the wind speed in the ventilation passage is detected. a wind speed sensor that outputs a defrosting start signal when the detected wind speed is below a set value; a rotation sensor that detects when the blower fan is in a driving state and outputs a rotation detection signal; A timer circuit that outputs a delay signal when a certain period of time has elapsed from the time when the detection signal was output, and a timer circuit that starts defrosting operation of the cooler when both the defrost start signal and the delay signal are output. A refrigerator characterized by being equipped with a defrosting circuit.