JP3413849B2 - Thermal response device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat responsive device mainly used for automatic rice cookers and the like. 2. Description of the Related Art A thermoresponsive device utilizing the Curie temperature of a ferromagnetic material has been widely applied to electric rice cookers and the like, and has been widely used in recent years until it is produced and sold overseas. FIG. 2 shows an example of the configuration of a rice cooker. The temperature sensing element 1 is a ferromagnetic alloy made of an Fe-Ni alloy and having a Curie temperature that matches the operating temperature of the thermoresponsive device. Reference numeral 3 denotes a heat-sensitive plate made of a material having good heat conductivity, such as aluminum.
It is closely attached to and fixed. Numeral 2 denotes a magnet which is magnetized NS on a surface facing the temperature-sensitive element 1 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 at its outer peripheral protruding portion, and gives a force repelling the attraction force of the temperature-sensitive element 1 and the magnet 2. Reference numeral 7 denotes a rod, one end of which is rotatably connected to the magnet holder 6 and the other end of which protrudes outside through a through hole of the case 4 to transmit the output of the thermoresponsive device to the outside. When the thermal responsive device having the above configuration is applied to a rice cooker, the Curie temperature of the thermosensitive element 1 is first set to 140 ° C., which is the temperature at which rice is cooked. Next, rice is cooked by pressing the heat-sensitive plate 3 on the bottom of a pot of a rice cooker (not shown) using a spring or the like. When the rice in the pot is cooked and the cooked rice is finished, the bottom temperature of the pot rises, and the temperature of the heat-sensitive element 1 tightly fixed to the heat-sensitive plate 3 of the thermo-responsive device also rises, and the Curie temperature ( When the temperature reaches 140 ° C.), the temperature sensing element 1 rapidly loses magnetism, the magnet 2 is pushed down by the spring 5, and the power is turned off by operating a switch (not shown) connected to the rod 7. It is. Such a thermal response device as described above has a reliable and simple structure, and has been used in almost all rice cookers using gas, not only electric rice cookers. [0004] When the thermoresponsive device having the above structure is used in a rice cooker, after the rice is cooked, the magnet 2 is released from the temperature sensing element 1 by a spring 5 and the rice cooker enters a warm state. The temperature of the magnet 2 is lower than the temperature of the pot kept at 70 ° C. in the main body 4, but the temperature becomes appropriate as a cockroach habitat, and the cockroaches inhabit and move around the surface of the thermosensitive element 1 and the magnet 2. When the rod 7 is pushed up to turn on the switch for cooking rice next time, if a cockroach is present on the magnet 2, the cockroach is crushed by the force for operating the rod 7 and the attraction force of the magnet 2, and the temperature-sensitive element 1 The body fluid of the cockroach spreads between the magnets 2. As the cooking proceeds and the temperature of the pot rises, the body fluid of the crushed cockroach dries and generates an adhesive force with drying, thereby bonding the magnet and the thermosensitive element. Therefore, even if the temperature-sensitive element exceeds the Curie temperature, the magnet 2 is not released from the temperature-sensitive metal, and the switch of the rice cooker becomes inoperable and continuous energization is performed. This led to a fire and was extremely inconvenient. An object of the present invention is to solve such a conventional problem and to provide a thermally responsive device that operates stably. According to the present invention, in order to achieve the above object, at least one of a temperature-sensitive element and a magnet attraction surface is provided with a highly non-adhesive material such as a fluororesin. It is configured. According to the thermal responsive device of the present invention, non-adhesiveness can be ensured on the surface facing the temperature-sensitive element and the magnet by the above configuration.
When the magnet is adsorbed to the temperature-sensitive element, it operates safely and reliably even if a living thing such as a cockroach intervenes. An embodiment of the present invention will be described in detail below. In FIG. 1, reference numeral 1 denotes a temperature-sensitive element, Fe-
It is made of a Ni—Cr alloy and has a fluororesin coating 8 on the surface facing the magnet 2. Reference numeral 3 denotes a heat-sensitive plate formed of a material having good thermal conductivity such as aluminum, and the temperature-sensitive element 1 is sandwiched and fixedly attached to the heat-sensitive plate 3 by a rising portion of an outer edge and a flange portion of the case 4. Reference numeral 2 denotes a magnet which is fixed to the holder 6 by a 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 coating 9, and the surface of the magnet 2 for performing NS magnetization is a fluororesin film coated with the temperature-sensitive element 1. It is adsorbed via 8,9. Reference numeral 6 denotes a spring as an elastic body for giving a repulsive force in advance so that the magnet 2 comes off from the temperature-sensitive element 1 accurately when the temperature-sensitive element 1 reaches the Curie temperature. It is held at the rising part. Reference numeral 7 denotes a rod which is used to operate external switches and the like when the temperature-sensitive element 1 reaches the Curie temperature, the magnet 2 loses the attraction force, and is repelled by the spring 5 to the position shown in FIG. It is rotatably mounted. 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, the insect such as a cockroach intervenes and the body fluid is crushed when the ON operation is performed. However, there is no fear that the magnet 2 and the temperature-sensitive metal 1 are bonded to each other to cause a malfunction. In addition, the fitting portion of the rod 7 that penetrates the case 4 does not require consideration for the passage of cockroaches, so that the opening of the case 4 through which the rod 7 passes can be made sufficiently large. Trouble such as locking to the penetrating portion due to the vertical movement of the rod 7 can be eliminated. In the above embodiment, the non-adhesive structure of the temperature-sensitive metal and the magnet is obtained by coating the surface of the temperature-sensitive element and the magnet facing each other with a fluororesin or the like. The goal is achieved on one side. The non-adhesive structure is not limited to the application of a non-adhesive material, but may include a non-adhesive thin plate or a non-adhesive material film. As described in the above embodiments, the heat responsive device of the present invention has a highly non-adhesive material such as fluororesin mounted on the surface where the temperature sensing element and the magnet are attracted. Even when cockroaches or the like intrude from outside, it always operates correctly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (A) ON of a heat responsive device in an embodiment of the present invention
(B) Sectional view of the state in which the thermal responsive device is OFF [FIG. 2] Cross-sectional view of a conventional thermal responsive device [Description of symbols] 1 Temperature-sensitive metal 2 Magnet 3 Thermal sensitive plate 4 Case 5 Spring 6 Holder 7 Rod 8, 9 Fluororesin

Claims (1)

(57) [Claim 1] A ferromagnetic material having a Curie temperature is used as a temperature sensing element, a magnet is attracted to the temperature sensing element, and a repulsion is generated between the temperature sensing element and the magnet. A thermo-sensitive device configured to attach an elastic body that gives a force to the thermo-sensitive element, wherein at the Curie temperature of the thermo-sensitive element, the magnet adsorbed to the thermo-sensitive element is separated from the thermo-sensitive element by the elastic body. A thermally responsive device in which a highly non-adhesive material such as a fluororesin is mounted on at least one of an attraction surface of the element and the magnet.