JPS6321211Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention allows you to set the time for additional cooking after the rice has finished cooking, etc.
This relates to a heat-retaining rice cooker operated by a microcomputer.

(b) Prior art As shown in Figure 1, the electric circuit diagram of a conventional heat-retaining rice cooker is one in which three heat-retaining heaters 4, 6, and 8 and one rice-cooking heater 2 are connected to a commercial AC power source 1. A step-down resistor A and a diode 9 are connected between the microcomputer 7 that sets the additional cooking time and the power supply 1, and the output from the microcomputer 7 is used to open and close the switch in accordance with the thermal response of the thermally responsive switch 10. It has a configuration in which a relay switch 3 and a thyristor 5 are wired to be conductive and non-conductive.
For this reason, the step-down resistor A consumes several watts of power, which wastes the power consumption, and requires a special step-down resistor with a high temperature resistance.Moreover, this step-down resistor has electronic components attached to it because of its temperature rise. The number of parts increases, the cost goes up, and the installation is troublesome, as it requires the effort and extra space to mount it away from the printed circuit board.

Note that the microcomputer that controls the microcomputer is set to operate with power of about 20 VDC, so a diode 9 and a step-down resistor A are required to rectify and step down the input power of 100 VAC.

(c) Purpose of the invention The present invention aims to eliminate the conventional drawbacks at once by utilizing the heat-retaining heater used for heat insulation as a step-down resistor.

(d) Structure of the invention The structure of the invention is such that the electricity supply to the rice cooking heater and the heat-retaining heater is controlled by a microcomputer, and the heat-retaining heater is a step-down resistor for supplying a step-down voltage to the microcomputer. be.

(e) Embodiment of the invention 1 is a commercial AC power supply in which a rice cooker heater 2 and a relay switch 3 are connected in series. A series circuit of a first heat retention heater 4 and a thyristor 5 is connected in parallel to the series circuit of the rice cooking heater 2 and the relay switch 3, and a second heat retention heater 6 is connected between the midpoints of the two series circuits. Connected. A microcomputer 7 sets the additional cooking time after rice cooking is completed, and a third heat-retaining heater 8 and a diode 9 are connected between the microcomputer 7 and the power source 1. The gate of the thyristor 5 is connected to the microcomputer (hereinafter referred to as microcomputer) 7, and the relay switch 3 is controlled by the microcomputer 7. Reference numeral 10 denotes a heat-responsive switch that senses the temperature rise of the rice to be cooked. Based on this heat detection, it controls the thyristor 5 on and off via the microcomputer 7, and also controls the relay switch 3.
is opened to finish cooking the rice.

To explain the operation of such a configuration, first, the third
AC 100V using insulation heater 8 as a step-down resistor
The voltage is stepped down to approximately 20V, and the diode 9 converts the alternating current to direct current, thereby enabling the microcomputer 7 to operate. When the heat-responsive switch 10 detects the rice cooking end temperature, the relay switch 3 is opened via the microcomputer 7, and after that, the microcomputer 7 closes the relay switch 3 again for an appropriate time to energize the rice cooking heater 2. It is something to do. After the rice cooking heater 2 is re-energized for additional cooking, the heat-responsive switch 10 detects the appropriate temperature for keeping warm and the microcomputer 7
The thyristor 5 is controlled ON and OFF via the thyristor 5 to shift to the heat-retaining operation.

(f) Effects of the invention As described above, the present invention utilizes the heat-retaining heater used for heat insulation as a resistor for the step-down resistor, which eliminates wasted power consumption and eliminates the need for a dedicated resistor for the step-down resistor. First, there is no need to provide a heat-resistant structure to the board on which electronic components are attached.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a conventional heat-retaining rice cooker, and FIG. 2 is an electric circuit diagram of the present invention. 2...Rice cooking heater, 7...Microcomputer, 8...Warming heater, 9...Diode.

Claims (1)

[Scope of utility model registration request] 1. A heat-retaining rice cooker in which power supply to a rice cooking heater and a heat-retaining heater is controlled by a microcomputer, characterized in that the heat-retaining heater is a step-down resistor for supplying a voltage drop to the micro-computer.