JPS60203214A - Switch apparatus of electric rice cooker - 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 Industrial Application The present invention relates to a switch device for an electric cooker used in general households.

Structure of the conventional example and its problems In the conventional electric rice cooker switch device, as shown in Figs. Similarly, a heat sensitive response section 4 is provided.

The heat-sensitive responsive part is composed of a temperature-sensitive ferrite part 6 whose magnetic permeability rapidly decreases at one Curie point, a permanent magnet, and a spring 7 that urges the permanent magnet 6 downward. In addition, since the entire heat-sensitive response part is urged upward by the spring 8,
When the rice cooking container 3 is not placed, a gap will be created between the temperature-sensitive ferrite 5 and the permanent magnet 6 even if the push button 9 is pressed.
Both do not attract each other and therefore have the function of detecting the presence or absence of a rice cooking container.

Electrically, the heat sensitive response section 6 connects to the lever 11 with the connector 10.
The lever 11 is configured to turn a microswitch 12 on and off.

However, in the above configuration, temperature is detected by the mechanical operation of the heat-sensitive response part, so it is difficult to balance the spring and adsorption force.

If dust or the like adheres to the rice cooker, it may malfunction and cause the rice to burn, or the temperature may rise until the temperature fuse is shut off. Another disadvantage is that it operates at low temperatures, resulting in the problem that the rice is not cooked properly.

OBJECTS OF THE INVENTION The present invention solves these conventional problems and provides a switch device for a rice cooker that eliminates a thermally responsive part due to mechanical operation and ensures reliable operation.

Structure of the Invention The electric rice cooking switch device of the present invention includes a permanent magnet that moves in a rice cooking container, a magnetic path that is magnetically coupled to the permanent magnet and whose magnetic permeability decreases at a single point, and a magnetic path that is connected to a control circuit. When a rice-cooking container having a detection element is mounted, the magnetic detection element is magnetically coupled to the permanent magnet through a magnetic path.

Furthermore, a Hall element, a reed switch, or the like is used as the magnetic detection element.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 3-4, 21a.

21b is an electric heating element, 22 is a rice cooking container, 23 is a case that houses a permanent magnet that moves vertically with the rice cooking container 22, and 24 is a ferrite that is magnetically coupled to the permanent magnet and whose magnetic permeability decreases at a single Curie point. 25 is a magnetic detection element.

Inside the case 23, as shown in FIG. 3, a permanent magnet 26 is held together with a magnetic path 24 made of ferrite or the like by a contact plate 27 and a case 28, and is urged upward by a spring 29. The case 23 is fixed to a hole provided in the center of the electric heating element 21a by a cut-and-raised portion 3o.

In FIG. 3, 31 is a printed board on which a magnetic detection element and a control circuit are mounted, and 32 is a start switch.

In FIG. 5, 33 is a self-holding circuit, the magnetic detection element 23 is connected to a reset terminal of the self-holding circuit 33, and the start switch 32 is connected to a set terminal of the self-holding circuit 33.

34 is a drive circuit, and 35 and 36 are electric heating elements 21b.

21a is a power control element such as a triac or relay for energizing, and 37 is a temperature fuse.

To explain the operation in the above configuration, the permanent magnet 26 is magnetically connected to a magnetic detection element 25 such as a Hall element by a magnetic path 24, but when a rice cooking container is not placed, the permanent magnet 26 is permanently connected by a spring 29. The magnet 26, the magnetic path 24, etc. are moved upward, the distance B between the magnetic sensing element 25 and the magnetic path 24 increases, the magnetic flux decreases, and the output of the magnetic sensing element 25 disappears, resetting the self-holding circuit 33. . Therefore, even if the start switch 32 is pressed, rice cooking will not start.

Next, when the rice cooking container 22 is placed, the permanent magnet 26 and the magnetic path 24 move downward, so the magnetic path 24 and the magnetic detection element 25
The distance B decreases and the magnetic flux increases, so the magnetic detection element 2
6 is generated, and when the start switch 32 is pressed, the self-holding circuit 33 self-holds. This output and force operates the drive circuit 34 and closes the relay contact 36, so that the electric nail is energized and rice cooking starts.

When rice cooking is finished and the temperature at the bottom of the rice cooking container rises, the temperature of the magnetic path 24 also rises due to heat conduction.

When this temperature reaches the Curie point of the material that formed the magnetic path, the magnetic permeability decreases rapidly, and therefore the magnetic flux to the magnetic detection element 25 also decreases, so the output of the magnetic detection element 25 also disappears, and the self-holding circuit 33 After resetting, the relay contact 36 is opened by the drive circuit, and the energization of the electric heating element 21a is stopped to complete the rice cooking.

After this, the electric heating element 21a shifts to a heat-retaining operation.

21b is energized by the triac 36.

Effects of the Invention As is clear from the above embodiments, the rice cooker switch device of the present invention eliminates the mechanically operated thermally responsive part and allows the decrease in magnetic permeability of the magnetic path to directly act on the magnetic detection element. By doing so, the reliability of the switch operation can be ensured.

Furthermore, it is a switch device that does not malfunction even if it is contaminated with oil or dirt, and is of great practical value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an electric rice cooker having a conventional Sui-J device, Fig. 2 is an enlarged sectional view of the same essential part, and Fig. 3 is an electric rice cooker equipped with a switch device according to an embodiment of the present invention. Cross-sectional view of the vessel,
FIG. 4 is an enlarged sectional view of the same main part, and FIG. 5 is a block diagram showing the electrical and magnetic configuration of the same embodiment. 21a...Electric heating element, 22...Rice cooking container, 24...Magnetic path, 26...Magnetic detection element, 26...Permanent magnet . Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Scope of Claims] (1) In an electric rice cooker having a detachable rice cooking container and an electric heating element, a permanent magnet that moves in the rice cooking container and a permanent magnet magnetically coupled to each other, and a magnetic detection element connected to a control circuit, and when a rice cooking container is placed, the magnetic detection element is magnetically coupled to the permanent magnet by the magnetic path. Electric rice cooker switch device. (2. In the switch device according to claim 1, a switch device for an electric rice cooker in which the magnetic detection element is a Hall element. (3) In the switch device according to claim 1, , a switch device for an electric rice cooker that uses a magnetic detection element as a reed switch.