JPH04209486A - Heating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating device such as a cooker that heats food or the like using a heating means.

2. Description of the Related Art A conventional heating device of this type will be explained using the block diagram shown in FIG.

That is, as shown in the figure, the heater 1 is controlled by the first switching means 2, the cooling fan 3 for cooling electrical parts etc. is controlled by the second switching means 4, and the air inside the refrigerator is discharged. The exhaust fan 5 is controlled by a third switching means 6. Further, the thermistor 7 is connected to temperature information detection means 8, and the control section 9 controls the first switching means 2 and the second switching means 2 based on the input from the temperature information detection means 8.
switching means 4 and third switching means 6
It is configured to control.

Problems to be Solved by the Invention However, with the configuration of such a conventional heating device,
If there is an abnormality in the temperature information detection means 8, the heater 1, cooling fan 3, and exhaust fan 5 cannot be controlled normally.
There was a risk that the cooking device itself could become abnormally heated.

SUMMARY OF THE INVENTION Accordingly, the present invention aims to solve the above-mentioned problems.The first object of the present invention is to provide a heating device such as a cooker that is configured to detect an abnormality and stop all operations when there is an abnormality in the temperature information detection means. The purpose is to

A second object is to provide a heating device that can more reliably determine whether there is an abnormality in the thermistor itself.

Means for Solving the Problems Therefore, in order to achieve the first object, the heating device of the present invention includes a heater, a first switching means connected to the heater, and a cooling fan for cooling electrical parts and the like. , a second switching means connected to the cooling fan, an exhaust fan, a third switching means connected to the exhaust fan, a thermistor, and a temperature information detection means connected to the thermistor. A sensitivity switching means connected to the detection means is provided, and a control section is provided in which the sensitivity switching means and the temperature information detection means are connected to the first switching means, the second switching means, and the third switching means. be.

Further, in order to achieve the second object, the present invention is configured to provide a control section that uses the sensitivity switching means to determine the oven of the thermistor using the sensitivity on the low temperature side, and determines short circuit using the sensitivity on the high temperature side.

Function: With the above-described configuration, the heating device of the present invention can detect an abnormality in the temperature information detection means by comparing the temperature information on the high temperature side and the low temperature side obtained by the sensitivity switching means.

Moreover, the sensitivity switching means allows determination of whether the thermistor is open or short-circuited with a more reliable sensitivity.

EXAMPLE Hereinafter, a heating device according to an example of the present invention will be described with reference to the accompanying drawings.

As shown in Figure 1, a heater 1 for heating food
0 is connected to a first switching means 11 for controlling the heater 10, a cooling fan 12 for cooling electrical parts etc. is connected to a second switching means 13 for controlling the cooling fan 12, and A third switching means 15 for controlling the exhaust fan 14 is connected to the exhaust fan 14 for discharging air from the heating chamber (not shown). The thermistor 16 for detecting the temperature inside the heating chamber is connected to a temperature information detection means 17, and the temperature information detection means 17 has a sensitivity switch for switching the output of the temperature information detection means 17 between a high temperature side and a low temperature side. Means 1
8 are connected. The control unit 19 is connected to the sensitivity switching means 18, the temperature information detection means 17, the first switching means 11, the second switching means 13, and the third switching means 15. The control part 1
Reference numeral 9 controls the sensitivity switching means 18, and controls the heater 10, the cooling fan 12, and the exhaust fan 14 based on the input from the temperature information detection means 17.

FIG. 2 is a circuit diagram of the thermistor 6 section, and the control section 19
When the transistor 20 of the sensitivity switching means 18 is turned off by the output P2 of the first variable resistor 21,
When the partial voltage of the thermistor 6 is input to the input P1 of the control unit 19 as the low temperature side voltage value ■1 and the transistor 20 is on, the combination of the second variable resistor 22 and the first variable resistor 21 The partial voltage of the resistor and thermistor 16 is inputted to the input P1 of the control section 19 as a voltage value (2) on the high temperature side.

In this embodiment, the voltage value ■1 on the low temperature side is inputted to the input PI of the control unit 19 at a period T that is equal to the power source same station wave number.
and the voltage value ■2 on the high temperature side, and if Vl<V2 as shown in FIG. 3(a), it is determined that the temperature information detection means 17 is normal, and as shown in FIG. 3(b). As shown, Vl>V
2, or if V1=V2 as shown in FIG. 3(C), the temperature information detection means 17 determines that there is an abnormality.

Further, in this embodiment, the control section 19 includes the sensitivity switching means 18.
Accordingly, when the temperature information detection means 17 is switched to the low temperature side, the accuracy is high when the input voltage is low, and when it is switched to the high temperature side, the accuracy is high when the input voltage is high, so the thermistor The determination as to whether the thermistor 16 is in the open state is made when the temperature information detection means 17 is switched to the low temperature side, and the determination as to whether the thermistor 16 is in the short state is made when the temperature information detection means 1
This is done when 7 is switched to the high temperature side.

Effects of the Invention As is clear from the above description, the heating device of the present invention provides the following effects.

(1) Since the output of the temperature information detection means is switched between the high, 4i side and the low temperature side by the sensitivity switching means, an abnormality in the temperature information detection means can be reliably detected by comparing both types of temperature information. Therefore, abnormal heating of the cooking device itself is prevented and safety is improved.

(2) In addition, by determining an open thermistor using the sensitivity on the low temperature side and a short circuit using the sensitivity on the high temperature side, it is possible to detect abnormalities in the thermistor more accurately and reliably. Improves safety.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a heating device according to an embodiment of the present invention, Fig. 2 is a circuit diagram of the thermistor section of the heating device, and Fig. 3 (a
l is the normal input voltage characteristic diagram of the heating device, Figure 3 (b
), (C) are input voltage characteristic diagrams of the heating device during abnormal conditions, and FIG. 4 is a diagram of the conventional heating device. 10... Heater, 11... First switching means, 12... Cooling fan, 13...
...Second switching means, 14...
Exhaust fan, 15... Third switching means, 16... Thermistor, 17... Temperature information detection means, 18... Sensitivity switching means, 1
9...Control unit. Name of agent: Patent attorney Akira Okaji and 2 others 1lff
l Figure 2 Figure 3 ρ Gin I% PI (M5J (C) Time opening (#Ls)

Claims (2)

[Claims] (1) A heater for heating food, a first switching means for controlling this heater, a cooling fan for cooling electrical parts, a second switching means for controlling this cooling fan, and air in the heating chamber. a third switching means for controlling the exhaust fan, a thermistor disposed in the heating chamber, and a temperature information detection means connected to the thermistor, the temperature information detection means A sensitivity switching means for switching the sensitivity of the temperature information detecting means is provided, the sensitivity switching means is controlled, and the output of the temperature information detecting means is input, and the first switching means, the second switching means, and the third switching means are provided. A heating device comprising a control section for controlling switching means. (2) The control unit determines whether there is an abnormality in the thermistor by using the sensitivity switching means to determine the open state using a sensitivity on the low temperature side;
2. The heating device according to claim 1, wherein the short circuit state is determined based on the sensitivity on the high temperature side.