JPH0620572A - Thermoreacting device - Google Patents

Abstract

PURPOSE:To prevent malfunctioning of a thermoreacting device that could be caused by the body fluid of cockroaches, etc., entering the device from the outside by applying a material with high non-stickiness such as fluororesin to the respective attracting faces of a temperature element and a magnet. CONSTITUTION:A material with high non-stickiness such as fluororesin is applied to the attracting surface of at least either one of a temperature element 1 made of a ferromagnetic substance having Curie temperature and a magnet 2 attracted to the temperature element 1, so as to prevent the temperature element 1 and the magnet 2 from being stuck to each other by the body fluid of cockroaches, etc. A spring 5 for providing resiliency is mounted between the temperature element 1 and the magnet 2. As the ambient temperature rises, the temperature of the temperature element 1 also rises and the temperature element 1 abruptly looses its magnetism at the Curie temperature, so the magnet 2 is pushed downward by the spring 5 and power supply is cut off by control of a switch connected to a rod 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat responsive device mainly used in automatic rice cookers and the like.

[0002]

2. Description of the Related Art A thermo-responsive device utilizing the Curie temperature of a ferromagnetic material has been widely applied to electric rice cookers, and has been widely used in recent years until it is produced and sold overseas. FIG. 2 shows an example of the structure of the rice cooker, in which the temperature sensitive element 1 is a ferromagnetic alloy made of an Fe—Ni alloy and having a Curie temperature matched with the operating temperature of the heat responsive device. Reference numeral 3 is a heat-sensitive plate made of a material having good heat conductivity such as aluminum.
It is fixed in close contact with. Reference numeral 2 denotes a magnet, the surface of which faces the temperature sensitive element 1 is N-S magnetized, and is fixed to a magnet holder 6 which can move up and down in the main body 4. The magnet holder 6 holds the spring 5 by its outer peripheral protruding portion and gives a force repulsive to the attraction force of the temperature sensitive element 1 and the magnet 2. Reference numeral 7 is a rod, one end of which is rotatably coupled to the magnet holder 6, and the other end of which is projected from the through hole of the case 4 to the outside so as to transmit the output of the thermal actuator to the outside.

When the thermal actuator having the above structure is applied to a rice cooker, first, the Curie temperature of the heat sensitive element 1 is preset to 140 ° C. which is the temperature at which rice is cooked. Next, the heat sensitive plate 3 is pressed onto the bottom of a pan of a rice cooker (not shown) by a spring or the like to cook rice. The rice in the pan is cooked, and the temperature of the bottom of the pan rises with the completion of rice cooking, and the temperature of the heat-sensitive element 1 that is closely fixed to the heat-sensitive plate 3 of the heat-actuating device also rises, and the Curie temperature ( 140 ° C.), the temperature sensitive element 1 rapidly loses magnetism, the magnet 2 is pushed downward by the spring 5, and the switch (not shown) connected to the rod 7 is operated to turn off the power. Is. Since this kind of heat response device as described above operates reliably and has a simple structure, it has been used not only in electric rice cookers but also in most rice cookers using gas.

[0004]

When the heat responsive device having the above-mentioned structure is used in a rice cooker, after the rice is cooked, the magnet 2 is released from the temperature sensing element 1 by the spring 5 so that the rice cooker enters a heat retaining state and the magnet 2 The temperature is lower than 70 ° C in the main body 4, but it is an appropriate temperature for the cockroach habitat, and the cockroaches settle in and go around the surface of the temperature-sensitive element 1 and the magnet 2 to cook rice next time. If the rod 7 is pushed up to turn on the sushi switch, and if there is a roach on the magnet 2, the roach is crushed by the force for operating the rod 7 and the attracting force of the magnet 2, and the roach of the temperature sensing element 1 and the magnet 2 is crushed. Body fluid of cockroach spreads in the meantime. When rice cooking progresses and the temperature of the pot rises, the crushed cockroach body fluid dries and an adhesive force is generated to bond the magnet and the temperature sensitive element. Therefore, even if the temperature sensitive element exceeds the Curie temperature, the magnet 2 is not released from the temperature sensitive metal, the switch of the rice cooker becomes inoperable, and continuous energization occurs. This caused a fire and was extremely inconvenient.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a thermal responsive device that operates stably.

[0006]

In order to achieve the above object, the present invention has a structure in which a highly non-adhesive material such as a fluororesin is attached to at least one of the temperature sensitive element and the attracting surface of the magnet. It is a thing.

[0007]

With the above structure, the thermal actuator of the present invention can secure non-adhesiveness on the opposing surfaces of the temperature sensitive element and the magnet.
When the magnet is adsorbed on the temperature-sensitive element, it operates safely and reliably even if creatures such as cockroaches intervene.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat responding device in the embodiments of the present invention will be described in detail below. In FIG. 1, reference numeral 1 denotes a temperature sensitive element, which is a Fe- element whose Curie temperature is matched with the operating temperature of the thermoresponsive device of the present invention.
It is made of a Ni-Cr alloy, and a fluororesin coating 8 is applied to the surface facing the magnet 2. A heat-sensitive plate 3 is made of a material having good heat conductivity such as aluminum, and the temperature-sensitive element 1 is sandwiched between the rising edge of the outer edge and the flange of the case 4, and the temperature-sensitive element 1 is closely fixed to the heat-sensitive plate 3. A magnet 2 is fixed to the holder 6 by the claw portion a of the holder 6.
The surface of the magnet 2 facing the temperature sensitive element metal 1 is coated with a fluororesin 9 and the surface of the magnet 2 is N-S magnetized. The magnet 2 is a fluororesin film coated with the temperature sensitive element 1. Adsorb via 8 and 9. Reference numeral 6 is a spring as an elastic body for giving a repulsive force in advance so that the magnet 2 can be accurately removed from the temperature sensitive element 1 when the temperature sensitive element 1 reaches the Curie temperature. It is held at the rising edge. Reference numeral 7 denotes a rod. When the temperature-sensitive element 1 reaches the Curie temperature, the magnet 2 loses the attraction force, and the spring 5 repels it to move it to the position shown in FIG. B, the holder 6 is operated to operate an external switch or the like. It is rotatably attached.

As described above, according to the present embodiment, since the non-adhesive surface treatment is always performed between the temperature sensitive element 1 and the magnet 2, insects such as cockroaches intervene and the crushed body fluid is turned on during the ON operation. Even if there is, there is no concern that the magnet 2 and the temperature-sensitive metal 1 will adhere to each other and cause malfunction. Further, the fitting portion of the rod 7 penetrating the case 4 does not need to be taken into consideration for the passage of cockroaches, so that it can be made sufficiently large as the opening portion through which the rod 7 of the case 4 passes. It is possible to eliminate any trouble such as locking of the penetrating portion due to the vertical movement of the rod 7.

In the above embodiments, the surfaces of the temperature-sensitive element and the magnet facing each other are coated with a fluororesin to obtain a non-adhesive structure of the temperature-sensitive metal and the magnet. The purpose is achieved even on one side. The non-adhesive structure is not limited to the coating of the non-adhesive material, and a non-adhesive thin plate may be interposed or a film of the non-adhesive material may be attached.

[0011]

As described in the above embodiments, in the thermal actuator of the present invention, the non-adhesive material such as fluororesin is attached to the surfaces on which the temperature sensitive element and the magnet are attracted, so that the thermosensitive element is not attached from the outside. Even if there is an invasion of cockroaches, it will always operate correctly.

[Brief description of drawings]

FIG. 1 (A) is a thermal response device ON in an embodiment of the present invention.
(B) Sectional view of the same thermal response device OFF state

FIG. 2 is a sectional view of a conventional thermal actuator.

[Explanation of symbols]

 1 Temperature Sensitive Metal 2 Magnet 3 Heat Sensitive Plate 4 Case 5 Spring 6 Holder 7 Rod 8, 9 Fluorine Resin

Claims (1)

[Claims] 1. A ferromagnetic material having a Curie temperature is used as a temperature-sensitive element, a magnet is attracted to the temperature-sensitive element, and an elastic body which gives a repulsive force is mounted between the temperature-sensitive element and the magnet. In the thermal response device configured such that, at the Curie temperature of the temperature sensitive element, the magnet adsorbed to the temperature sensitive element is separated from the temperature sensitive element by the elastic body, at least the attraction surfaces of the temperature sensitive element and the magnet are A thermal response device with a highly non-adhesive material such as fluororesin attached to either one.