JPH0216124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a switch device for an electric rice cooker used in general households. With the spread of microcomputers, microcomputers are now being used in control circuits of electric rice cookers. The conventional method generally adopted as a means of inputting signals to a microcomputer is the first method.
This method uses electrical contacts as shown in the figure. In FIG. 1, 1 is a contact switch connected to an input terminal of a microcomputer 2, and a dotted frame 3 is a control circuit. 4 is a power supply terminal, 5 and 6 are electric heating elements, 7 is a relay contact that is opened and closed by the control circuit 3, and 8 is a triac. The switch 1 opens and closes in mechanical conjunction with a temperature sensor that detects the temperature of the rice cooker.

However, in the above configuration, if there is chattering when the switch 1 opens and closes the contacts, the input signal to the microcomputer 2 will be disturbed, causing malfunction. In addition, microcomputer 2
Noise is likely to enter the wiring between the input terminal and the contact point, and impulse noise generated in the power supply line may cause malfunction. An object of the present invention is to provide a switch device for an electric rice cooker that operates stably and is free from such malfunctions.

[Structure of the invention]

The switch device for an electric rice cooker of the present invention is an electric rice cooker equipped with an electric heating element controlled by a power controller operated by a signal from a microcomputer, and a Hall element switch is connected to an input terminal of the microcomputer. The electric rice cooker is characterized in that an operating lever that operates a permanent magnet that drives the Hall element switch is mechanically coupled to a temperature sensor that detects the temperature of the rice cooker of the electric rice cooker.

Embodiments of the present invention will be described with reference to FIGS. 2, 3, and 4. In FIG. 2, 11 is a Hall element switch having a Hall element connected to an input terminal of a microcomputer 12, and 13 is a permanent magnet for driving the Hall element. Reference numeral 14 denotes a power controller operated by a signal from the microcomputer 12, which controls a relay contact 15 or a triac 16. 17 is an electric heating element for keeping warm;
18 is an electric heating element for cooking rice, and 19 is a power terminal. The permanent magnet 13 facing the Hall element switch 11 is attached to a support 2 as shown in FIGS. 3 and 4.
0, the support 20 is connected to an actuating lever 21. The operating lever 21 is rotatably attached to a fulcrum 22, has a push button 23 at one end, and is mechanically coupled to a temperature sensor 25 for detecting the temperature of the rice cooker 24 at the other end. Reference numeral 26 denotes a wiring board to which the microcomputer 12 is attached, and is housed together with an LED 27 and the like in a switch box 29 provided in the front of the main body 28 of this electric rice cooker. In the above embodiment, the Hall element switch 11 and the microcomputer 12 are housed in the same package, but it is also possible to separate them and arrange them separately. In FIG. 3, 30 is an inner pot of this electric rice cooker, and an electric heating element 18 for cooking rice is provided at the bottom thereof, and an electric heating element 17 for keeping warm is provided at the side thereof. 31 is a lid body.

Next, its effect will be explained. When a permanent magnet approaches the Hall element and the magnetic field changes, an electromotive force is generated and the Hall element switch 11 is connected to the microcomputer 12.
Input the signal to. In FIG. 4, the pushbutton 23
When the permanent magnet 13 is moved from the solid line position to the dotted line position by pressing , a signal is input to the microcomputer 12, which operates the power controller 14 to close the relay contact 15.
The electric heating element 18 for rice cooking is energized to start cooking rice. When the rice cooking is finished, the temperature of the rice cooking pot rises, and the temperature detector 25 detects this. Since the temperature sensor 24 is mechanically connected to the operating lever 21 of the permanent magnet 13, when it detects that rice cooking is completed, the operating lever 21 is returned from the dotted line position to the solid line position. The change in the magnetic field at this time generates an electromotive force in the Hall element, and the Hall element switch 11 inputs a signal to the microcomputer 12. The power controller 14 opens the relay contact 15 in response to a signal from the microcomputer 12 to stop energizing the electric heating element 18 for rice cooking, moves to a warming operation, and energizes the electric heating elements 17 and 18 by the triax 16.

〔Effect of the invention〕

As described above, the switch device of the present invention employs a Hall element switch and operates it by operating a permanent magnet, so it is possible to input a stable signal to a microcomputer. There is no room for contact chatter or power line impulse noise to enter the microcomputer unlike in other devices, and there is no risk of rice cooking malfunctioning. Therefore, it has the effect of achieving the purpose of the invention.

[Brief explanation of drawings]

Figure 1: Electrical circuit diagram of a conventional switch device, Figure 2: A diagram showing the basic technical idea of the switch device of the present invention, Figure 3: Overall diagram of an electric rice cooker equipped with the switch device of the present invention. Diagram showing the structure, Figure 4:
FIG. 4 is an enlarged view of the switch device shown in FIG. 3; 11... Hall element switch, 12... Microcomputer, 13... Permanent magnet, 14... Power controller, 15... Relay contact, 16... Triax, 17, 18... Electric heating element, 19... Power supply Terminal, 20... Support, 21... Actuation lever,
22... Fulcrum, 23... Push button, 24... Rice cooker, 25... Temperature detector, 26... Wiring board, 2
7...LED, 28...Main body, 29...Switch box, 30...Inner pot, 31...Lid body.

Claims (1)

[Scope of Claims] 1. In an electric rice cooker equipped with an electric heating element controlled by a power controller operated by a signal from a microcomputer, a Hall element switch is connected to an input terminal of the microcomputer, and the Hall element switch is connected to an input terminal of the microcomputer. A switch device for an electric rice cooker, characterized in that an operating lever that operates a permanent magnet that drives an element switch is mechanically coupled to a temperature sensor that detects the temperature of a rice cooker of the electric rice cooker. 2. The switch device for an electric rice cooker according to claim 1, wherein the Hall element switch is housed in the same package as the microcomputer.