JPS6045443B2 - temperature control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device that allows the temperature of a load to be set over a wide range using a single temperature setting device.

Conventionally, for example, in an electrical open circuit, a thermistor as a temperature sensing element and a variable resistor as a temperature setting device were installed in a bridge circuit for temperature detection, and the temperature inside the refrigerator was set to various values by the variable resistor. By inserting or disconnecting a resistor in the bridge circuit by means of a selection switch,
Some devices allow selection of a low temperature region and a high temperature region, thereby allowing the temperature inside the refrigerator to be set over a wide range.

According to such a conventional configuration, when setting the internal temperature of the refrigerator, it is necessary to operate both the temperature setting device and the temperature range selection switch, which has the disadvantage that it is easy to make an erroneous operation and the operation is complicated. Ta. The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to interlock the temperature setting device so that the impedance change within a predetermined range is repeated multiple times within the entire stroke of the operating member for temperature setting. At the same time, a selection switch for switching the temperature detection area of the temperature sensing element under the same value of impedance of the temperature setting device is linked to the operation member, and the temperature sensing area of the temperature sensing element is changed to the impedance of each time of the temperature setting device. By having a configuration in which the temperature is set differently depending on the change, arbitrary temperature settings over multiple temperature ranges can be performed with only one operation using the same operating member, and therefore, the same temperature setting can be performed twice. It is an object of the present invention to provide a temperature control device which is free from the risk of erroneous operation and can eliminate the complexity of operation compared to a device which is controlled by operating two members.

An embodiment of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes an electric opener having a roasting chamber 2 and an operation panel 3 on the side of the front surface, respectively.In the roasting chamber 2, an upper heater 4 and a lower heater 5 are arranged, and the operation panel 3 A support plate 6 is arranged on the back side of the support plate 6 to face it. In FIGS. 2 and 3, a shaft 7 is attached to the support plate 6, and the impedance is changed by the rotation of the shaft 8. A temperature setting device, such as a variable resistor for temperature setting, has a pulley 9 attached to its shaft 8.The variable resistor 7, unlike ordinary ones, rotates the shaft 8 continuously in the same direction many times. The shaft 8 is configured so that the resistance value changes as shown by curve 10 in FIG. In addition, in Fig. 5, R is the resistance value,
0 is the rotation angle of the shaft 8. Reference numerals 11 and 12 indicate other pulleys which are provided vertically apart from each other on the support plate 6 so as to form a three-point arrangement together with the pulley 9. is being passed over.

Reference numeral 14 designates a rod-shaped operating member for temperature setting, and a grooved sliding member 15 is provided at one end of the operating member, which is connected to the support plate 6.
It is slidably fitted into a long groove-shaped sliding groove 16 formed so as to be oriented vertically.

The other end of the operating member 14 is connected to the sliding groove 1 in the operating panel 3.
It protrudes to the outside through a long groove 17 formed opposite to 6 in a loose manner, and a knob 18 is attached to the protruding end.
Reference numeral 19 denotes a selection switch attached to the support plate 6, which is opened and closed by rotational displacement of an operating plate 20 it has.

Reference numeral 21 denotes a pressing plate attached to the operating member 14, and the vicinity of the tip thereof is pressed against the operating plate 20 as the operating member 14 moves up and down.
The selection switch 19 is opened by sliding it and turning it in the direction of arrow 22 in FIG.

In this embodiment, the long groove 17 of the operating member 14 shown in FIG.
During the entire stroke L along the stroke L, the selection switch 19 is maintained in the open state during movement in section B of sections A1 and B, which are divided into upper and lower sections, and in the closed state during movement in section A. It is becoming more and more common. Then, the operating member 14 is inserted. The middle of the shaft is connected to a belt 13 between pulleys 11 and 12, and when the operating member 14 is moved by the full stroke L, the belt 13 rotates the shaft 8 of the variable resistance 7 twice, and at this time, the shaft 8 rotates once in section A. It rotates and then makes one more revolution in section B. Like this, variable resistor 7
The shaft 8 and the operating member 14 are linked together via the pulleys 9, 11, 12 and the belt 13. Even when the rotational stroke of the shaft 8 is large, by appropriately selecting the diameter of the pulley 9, the operating member This is to make it possible to easily limit the strokes on the operation panel 3 of 14 to a desired value. Next, the electrical configuration will be explained with reference to FIG.

In FIG. 4, 23 is an AC power supply, one end of which is connected to the bus bar 24, and the other end is connected to the timer switch 2.
5. It is connected to a bus bar 28 via a voltage reduction resistor 26 and a diode 27 for forming a DC power source. Reference numeral 29 denotes a bridge circuit for temperature setting, and as shown in the figure, on each side of this, the variable resistor 7, a temperature sensing element installed to detect the temperature of the roasting chamber 2, such as a thermistor 30 with a negative characteristic, and a resistor are installed. 31 and another resistor 32 are provided respectively, and the resistor 3
3 and the selection switch 19 is connected in parallel with the resistor 31, and this parallel circuit constitutes a temperature sensing region switching circuit 34.

35 connects the output of the bridge circuit 29 to its output terminals 36 and 3.
a comparator constituted by an operational amplifier receiving from 7;
8 is a Schmitt circuit which receives the output from the comparator 35 and operates the relay 39 while a voltage difference is generated between the output terminals.

On the other hand, one end of each of the upper heater 4 and the lower heater 5 is connected to the bus bar 24, and each other end is connected to the upper heater switch 40, the lower heater switch 41, and the normally open contacts 39a and 39b of the relay 39. The common connection point 43 connects the timer switch 25 and the resistor 2.
It is connected to the common connection point with 6. In addition, 25a shown in FIG. 1 is the operator of the timer switch 25, 40a and 4
Reference numerals 1a are operating levers for the upper heater switch 40 and the lower heater switch 41, respectively. Next, the upper heater switch 40
The operation of the above structure will be explained with reference to FIG. 6 assuming that both the upper and lower heater switches 41 are closed. In FIG. 6, θ on the horizontal axis is the rotation angle of the shaft 8 of the variable resistor 7. , and T on the vertical axis represents the internal temperature (temperature inside the roasting chamber 2).

Now, taking as an example the case where the temperature is set by moving the operating member 14 in section A of its entire stroke L, that is, between points P1 and P2 shown in FIG.
When the operating member 14 is moved within the section, the pressing plate 21 is separated from the operating plate 20 and is not pressed in the direction of the arrow 22, so the selection switch 19 is closed as shown by the dotted line in FIG. Therefore, the resistance value of the temperature detection area switching circuit 34 is the parallel combined resistance value of both resistors 31 and 33, and the bridge circuit 29 is selected for the low temperature detection area. Now, when the operating member 14 is moved upward from point P1 to point P2, the resistance value of variable resistor 7 decreases as shown by curve 10 in FIG. do. Therefore, the bridge circuit 29 has its output terminals 36,3
In order to achieve an equilibrium state in which no potential difference occurs between the variable resistor 7 and the thermistor 30, the resistance value of the thermistor 30 must decrease as the resistance value of the variable resistor 7 decreases. The higher the price, the higher the price. Changes in the set value of the internal temperature in such a low temperature detection region are shown by a straight line 42 in FIG. Regarding the above, when the operating member 14 is moved from the A section to the B section, the pressing plate 21 is moved to the operating plate 20.
is pressed in the direction of arrow 22 to open the selection switch 19.

Then, the temperature detection area switching circuit 34 includes only the resistor 31, and the resistance value increases compared to when both resistors 31 and 33 are in parallel.
voltage becomes lower than when the selection switch 19 is in the closed state, and accordingly, in order for the bridge circuit 29 to be in an equilibrium state, the potential at the other output terminal 36 must also become lower, so the variable resistor If the resistance value of the thermistor 30 were to be the same as that in the closed state of the selection switch 19, the low resistance value of the thermistor 30 would have to be further reduced, i.e. it would have to experience a higher temperature than the lower layer, Therefore, the temperature detection range by the thermistor 30 becomes high, and in this way, the bridge circuit 29 is selected for the high temperature detection range. When the operating member 14 moves from point P2 to point P3 in such a high temperature detection area, that is, section B, the shaft 8 of the variable resistor 7 enters the second rotation state, and even during this second rotation, the variable resistor 7 Since the resistance value changes with the same characteristics as in the first rotation shown in FIG. 5, the higher the operating member 14 is moved upward, the higher the set temperature inside the refrigerator becomes. This state is indicated by the dotted line 4 in Figure 6.
3. In this embodiment, when the operating member 14 is moved from point P1 to point P2, the temperature inside the refrigerator changes from 35°C to 120°C.
The temperature is set to an arbitrary temperature between 120°C and 250°C when the temperature is moved from point P2 to point P3. The temperature inside the refrigerator is controlled by the above-described temperature settings as follows. That is, if the internal temperature is lower than the temperature set by the operating member 14,
A potential difference is generated between the output terminals 36 and 37 of the bridge circuit 29, and this potential difference causes the comparator 35 to produce an output, which energizes the relay 39 via the Schmitt circuit 38, and its normally open contacts 39a, 39b is turned on, and the upper heater 4 and lower heater 5 are energized. As a result, the temperature inside the refrigerator rises, and when this becomes approximately equal to the set value, there is no potential difference between the output terminals 36 and 37 of the bridge circuit 29, and the relay 39 returns to its normal state, turning off its normally open contacts 39a and 39b, and the upper The heater 4 and the lower heater 5 are cut off. Through such operations, the inside of the refrigerator is controlled to maintain the set temperature. As understood from the embodiments described above, the present invention operates in such a way that the temperature setting device is repeatedly changed in a predetermined range of impedance within the entire stroke of the operating member for temperature setting, and also sets the temperature. A selection switch for changing the temperature detection area of the thermosensor under the same value of impedance of the device is linked to the operating member, and the temperature detection area of the thermosensor is changed according to each impedance change of the temperature setting device. It is characterized by having a different configuration for each, and according to this configuration, when the operating member is moved, the selection switch is activated in conjunction with this, and the temperature detection area by the temperature sensing element is automatically switched. Temperature settings over different temperature ranges can be performed with a single operation using the same operating member, and therefore there is no risk of erroneous temperature setting operations and the operation is extremely simple compared to systems that require multiple operations. Moreover, since the temperature setting device is used in such a manner that impedance changes within a predetermined range are repeated multiple times regarding temperature setting from the upper limit to the lower limit, the impedance of the same value differs depending on the impedance value. Multiple temperature settings can be made, and compared to systems that always set different temperatures using different impedance values, the load temperature can be controlled over a wide range even with a small temperature setting device with a narrow impedance change range. It has the excellent effect of opening the door.

[Brief explanation of drawings]

The drawings relate to an embodiment in which the present invention is applied to an electrical open circuit. FIG. 1 is a perspective view showing the main parts of the electrical open circuit, and FIGS. 2 and 3 are a side view and a temperature setting mechanism, respectively. 4 is a wiring diagram of the temperature control circuit, FIG. 5 is a characteristic curve diagram of the variable resistor, and FIG. 6 is a characteristic curve diagram of the temperature inside the refrigerator. In the figure, 7 is a variable resistor (temperature setting device), 9 is a pulley, 13
is a belt, 14 is an operating member, 19 is a selection switch, 20
21 is an actuating plate, 21 is a pressing plate, 29 is a bridge circuit, 30 is a thermistor (temperature sensing element), 34 is a temperature detection area switching circuit, 35 is a comparator, and 39 is a relay.

Claims (1)

[Claims] 1. A temperature sensing element, a temperature setting device whose impedance can be changed to set the temperature detected by this temperature sensing element, and a selection for switching the temperature detection area by the temperature sensing element under the same value of impedance of this temperature setting device. switch and
an operating member that is arranged to move within a certain range and interlocks the temperature setting device so that the impedance change within the predetermined range is repeated a plurality of times within the entire stroke;
A temperature control device characterized in that the selection switch is operated in conjunction with the operation member so that the temperature detection area of the temperature sensing element is made different depending on each impedance change of the temperature setting device.