JPH0519733Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a temperature control device for a refrigerator configured to open and close a cold air outlet using a motor-driven damper.

(Prior art) In conventional refrigerators, a temperature control device equipped with a motor-driven damper fully opens the damper to supply cold air into the refrigerator when the temperature inside the refrigerator rises above a set temperature, while also supplying cold air into the refrigerator. When the internal temperature drops below the set temperature, the damper is closed to stop the supply of cold air, thereby maintaining the inside of the refrigerator at a predetermined set temperature.

(Problems to be Solved by the Invention) Generally, the amount of cold air blown out is set to be large so that the inside of the refrigerator can be cooled quickly even when the temperature inside the refrigerator increases by a large amount with respect to the set temperature. However, if cold air is blown out strongly even after the temperature inside the refrigerator approaches the set temperature, the area near the cold air outlet will be cooled too much, creating a large disparity in the temperature distribution inside the refrigerator. Despite this, in the conventional configuration described above, when the damper is opened, it is always fully opened, so when the temperature difference between the internal temperature and the set temperature is small, the cold air blows out too strongly. , the area near the cold air outlet becomes too cool, creating a large disparity in the temperature distribution inside the refrigerator. Moreover, it is difficult to adjust the temperature to follow minute temperature changes, and the range of fluctuations in the internal temperature generally increases.

The present invention aims to solve these problems, and its purpose is to make the temperature distribution inside the refrigerator uniform, and to adjust the temperature to follow minute temperature changes. An object of the present invention is to provide a temperature control device for a refrigerator that can reduce the range of variation in internal temperature.

[Structure of the invention] (Means for solving the problem) The temperature control device of the invention has a temperature sensor whose resistance value changes depending on the temperature inside the refrigerator, and a motor-driven damper that is linked to the opening/closing operation. and a variable resistor for detecting the opening whose resistance value changes, and the opening of the damper is adjusted by controlling the operation of the motor so as to bring the bridge circuit into an equilibrium state. It is something.

(Function) When the temperature inside the refrigerator increases, the resistance of the temperature sensor in the bridge circuit changes accordingly, causing the equilibrium state of the bridge circuit to collapse. Under this condition, the motor starts operating, and the damper is operated in a direction to bring the internal temperature closer to the set temperature, and in conjunction with this, the resistance value of the opening detection variable resistor changes.
This causes the motor to stop when the bridge circuit reaches equilibrium. In this way, the opening degree of the damper is adjusted according to the temperature difference between the internal temperature and the set temperature.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. First, in FIG. 4 showing the schematic configuration of a refrigerator, 1 is a refrigerator main body, inside which a refrigerator compartment 2 and a freezer 3 are formed, and a cooler 4 and a fan 5 are arranged at the back of the freezer compartment 3. has been done. The cold air generated by these coolers 4 and fans 5 is
The air is supplied into the freezer compartment 3 and is also guided through the cold air supply duct 6 to the cold air outlet 7 at the upper rear side of the refrigerator compartment 3 . Reference numeral 8 denotes a damper that opens and closes the cold air outlet 7. The configuration of a drive mechanism 8a of this damper 8 will be explained based on FIG. 3. A motor 9 drives the damper 8. The motor 10 is a direct current motor capable of rotating in forward and reverse directions, and a drive gear 10 is fitted onto its rotating shaft. A first reduction gear 11 is meshed with this drive gear 10, and a second reduction gear 12 is provided coaxially with this first reduction gear 11, and both reduction gears 11 and 12 rotate integrally. do. Further, the second reduction gear 12 includes a driven gear 1
3 are meshed with each other, and a cam (not shown) provided on this driven gear 13 is in contact with the lower end of the support lever 14 of the damper 8. In this case, the support lever 14
is rotatably supported around a support shaft 15, and is rotated in the direction of arrow C (opening direction) or the opposite direction (closing direction) by rotation of the driven gear 13 (cam). The support lever 14 is biased in the closing direction by a spring (not shown) and is configured to maintain a state of contact with the cam. For the drive mechanism 8a configured as above, 16 is an opening detection variable resistor for detecting the opening of the damper 8;
For example, it is composed of a rotary variable resistor, and its operating shaft 16a is connected to the driven gear 13 (cam) via a connecting member 17 and rotates together with the driven gear 13 (cam).

Next, the configuration of the operation control circuit for the motor 9 will be explained based on FIG. 18 is a temperature setting variable resistor for setting the cooling temperature in the refrigerator compartment 2, and 19 is a temperature sensor that detects the temperature in the refrigerator compartment 2 (hereinafter referred to as "internal temperature"), for example, a negative temperature characteristic. It consists of a thermistor with A series circuit of the temperature setting variable resistor 18 and the temperature sensor 19, the opening detection variable resistor 16 and the fixed resistor 2
The bridge circuit 22 is configured by connecting the series circuit with the DC power supply 21 in parallel to the DC power supply 21. 23 is a DC amplifier that drives the motor 9, one input terminal a of which is connected to the common connection point 2 between the opening detection variable resistor 16 and the fixed resistor 20.
4, and the other input terminal b is connected to a common connection point 25 between the temperature setting variable resistor 18 and the temperature sensor 19. Incidentally, FIG. 2 shows the relationship between the temperature inside the refrigerator, the resistance value of the temperature sensor 19, the resistance value of the opening detection variable resistor 16, and the opening degree of the damper 8.

Next, the operation of the above configuration will be explained. For example, the set temperature can be set using the temperature setting variable resistor 18.
When the temperature is set to t ₁ (see FIG. 2), the bridge circuit 22 enters an equilibrium state as described later when the temperature inside the refrigerator compartment 2 reaches the set temperature t ₁ . The equilibrium conditions of the bridge circuit 22 at this time are:
The resistance value of the temperature setting variable resistor 18 is R ₁ , the resistance value of the temperature sensor 19 is R _th , the resistance value of the opening detection variable resistor 16 is R _V , and the resistance value of the fixed resistor 20 is R ₂ Then, it can be expressed by the following equation (1).

R _th · R _V = R ₁ · R ₂ ...(1) In this case, unless the user changes the set temperature t ₁ , the resistance value R ₁ of the temperature setting variable resistor 18 is constant, so (1 ) The right side (R ₁・R ₂ ) of the equation is constant. In the equilibrium state, the bridge circuit 22
Since the potentials Va and Vb at both common connection points 24 and 25 are equal and the potential difference between both input terminals a and b of the DC amplifier 23 is zero, the output voltage of the DC amplifier 23 becomes zero and the motor 9, and as a result, the operation of the damper 8 is stopped. In this case, the second
As shown in the figure, when an equilibrium state is reached at the set temperature _t1 , the opening degree of the damper 8 remains at A (half-open state), and the resistance value _R1 of the variable resistor 16 for opening degree detection becomes equal to the temperature sensor 19. equal to the resistance value R _th (however,
The condition is that R ₁ = R ₂ = R _th = R _V in an equilibrium state).

After this, when the temperature inside the refrigerator rises from t ₁ to t ₂ by, for example, opening the door 26, the resistance value R _th of the temperature sensor 19 with negative temperature characteristics increases accordingly.
decreases, and the potential Vb at the common connection point 25 decreases. As a result, since Va>Vb, a potential difference is generated between both input terminals a and b of the DC amplifier 23,
A DC voltage corresponding to the potential difference is applied from the DC amplifier 23 to the motor 9, and the motor 9 is started.
In this case, the potential Va on the input terminal a side is
Since the voltage is higher than the potential Vb on the side, a positive DC voltage is applied to the motor 9, and the motor 9 rotates in the forward direction.
The rotation of the motor 9 is transmitted to the driven gear 13 (cam) via the drive gear 10 and both reduction gears 11 and 12, and the cam rotates in the forward direction. As a result, the support lever 14 of the damper 8 rotates in the direction of arrow C (opening direction), and the opening degree of the damper 8 increases from A to B in FIG. At this time, the operating shaft 16a of the opening detection variable resistor 16 rotates together with the rotation of the driven gear 13, and the opening detection variable resistor 1
The resistance value R _V of 6 increases. Then, the multiplication value of this R _V and the resistance value R _th of the temperature sensor 19 (R _th・R _V )
When R ₁ and R ₂ reach a constant value, the bridge circuit 22 enters an equilibrium state and both points 24 and 25
The potentials Va and Vb become the same potential, and the DC amplifier 23
The output voltage becomes zero and the motor 9 stops. In this way, when the temperature inside the refrigerator is _t2 , the damper 8 temporarily stops at the opening degree B (see FIG. 2).
In this state, since the damper 8 is in a relatively wide open state, a relatively large amount of cold air is blown out from the cold air outlet 7 into the refrigerator compartment 3. As a result, the temperature inside the refrigerator gradually decreases, but since the resistance value R _th of the temperature sensor 19 increases as the temperature inside the refrigerator decreases, the balance of the bridge circuit 22 is disrupted, and both points 24 and 24 , 25 is Va
＜Vb. Along with this, a negative DC voltage is applied to the motor 9 from the DC amplifier 23, and the motor 9
rotates in the opposite direction. As a result, the driven gear 13 (cam) rotates in the opposite direction, and the support lever 14 of the damper 8
is rotated in the closing direction (opposite direction to arrow C in FIG. 2), the opening degree of the damper 8 is narrowed, and the amount of cold air blown out is reduced. In conjunction with the operation of the damper 18, the resistance value R _V of the opening detection variable resistor 16 decreases, and the multiplication value of the resistance values R _th and R _V becomes a constant value (R ₁ ·
R ₂ ), the bridge circuit 22 enters an equilibrium state and the motor 9 (damper 8) stops. Thereafter, the above-described operation is repeated to bring the temperature inside the refrigerator closer to the set temperature _t1 .

According to the above configuration, when the temperature difference between the internal temperature and the set temperature _t1 is large, the opening degree of the damper 8 is increased to increase the amount of cold air blown out, thereby cooling the inside of the refrigerator compartment 2. However, as the temperature inside the refrigerator decreases, the opening degree of the damper 8 is automatically gradually reduced to gradually reduce the amount of cold air blown out. This prevents the parts near 7 from being too cooled by strong cold air, and even after the internal temperature approaches the set temperature _t1 , a small amount of cold air is gently circulated to every corner of the refrigerator compartment 2. The temperature distribution within the refrigerator compartment 2 is made uniform. Moreover, since the opening degree of the damper 8 (the amount of cold air blown out) can be adjusted continuously according to the temperature difference between the internal temperature and the set temperature _t1 , the temperature can be adjusted to follow minute temperature changes. This makes it possible to reduce the fluctuation range of the temperature inside the refrigerator.

In the above embodiment, a DC motor is used as the motor 9, but an AC motor capable of forward and reverse rotation may be used. Furthermore, in the above embodiment,
Although the operating shaft 16a of the opening detection variable resistor 16 is configured to rotate together with the driven gear 13 (cam), for example, it may be rotated integrally with the support lever 14 of the damper 8, Alternatively, the variable resistor for opening degree detection may be configured as a linear sliding type variable resistor, and the operating lever of the linear sliding type variable resistor may be configured to rotate integrally with the drive gear 10. A configuration in which they are connected may also be used.

In addition, the present invention can be applied not only to the damper device of the refrigerator compartment 2 as in the above embodiment, but also to the damper device of the specification switching room such as those installed in recent large refrigerators. Various modifications can be made without departing from the scope of the invention.

[Effects of the invention] As is clear from the above explanation, the opening degree of the damper is automatically adjusted according to the temperature inside the refrigerator, so the amount of cold air blown out can be reduced as the temperature inside the refrigerator decreases. It has the excellent effect of being able to gradually reduce the temperature distribution in the refrigerator, making the temperature distribution inside the refrigerator uniform, and making it possible to adjust the temperature to follow minute temperature changes, thereby reducing the range of fluctuations in the temperature inside the refrigerator. play.

[Brief explanation of the drawing]

The drawing shows one embodiment of the present invention.
The figure is an electrical circuit diagram of the main parts, Figure 2 is a diagram showing the relationship between the resistance change of the temperature sensor and variable resistor for opening detection, and the opening of the damper, and Figure 3 is an enlarged perspective view showing the damper drive mechanism. 4 are longitudinal sectional side views of the refrigerator. In the drawing, 7 is a cold air outlet, 8 is a damper, 9 is a motor, 16 is a variable resistor for opening detection, 18 is a variable resistor for temperature setting, 19 is a temperature sensor, 20 is a fixed resistor, and 22 is a bridge. The circuit 23 is a DC amplifier.

Claims (1)

[Scope of utility model registration request] A damper driven by a motor opens and closes a cold air outlet for blowing cold air into a refrigerator, and a temperature sensor whose resistance value changes depending on the temperature inside the refrigerator, and a temperature sensor that controls the opening and closing operation of the damper. A configuration including a bridge circuit having a variable resistor for opening detection whose resistance value changes in conjunction, and controlling the operation of the motor to adjust the opening of the damper so as to bring the bridge circuit into a balanced state. A temperature control device for a refrigerator characterized by: