JPH0743218A - Temperature sensor for cooking utensil - Google Patents

Abstract

PURPOSE:To improve the heat conduction from an object to be heated to a heat-sensitive element by mounting the heat sensitive element in an insulating heat collecting plate composed of an aluminum nitride having high heat conductivity. CONSTITUTION:A heat sensitive body A is constituted of an inner case 7, resin case 3, aluminum cap 6, heat sensitive element 1 arranged in the upper section of the case 3, insulating heat collecting plate 2, and reed switch 4 held in the lower section of the case 3. The upper surface of the plate 2 is closely adhered to the internal surface of the cap 6 and the upper outer peripheral surface is closely adhered to the recessed surface of the plate 2. Therefore, the heat received by the cap 6 from an object to be detected is transferred to the element 1 through the plate 2. The plate 2 is composed of an aluminum nitride having the highest heat conductivity among insulators. Therefore, the thermal responsiveness of the plate 2 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor for a cooker using a thermistor as a temperature detecting element, which is used for detecting the temperature of a rice cooker, a rice cooker or the like and detecting the completion of cooking, and particularly has improved thermal response. The present invention relates to a temperature sensor for a cooker.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show an example of a conventional temperature sensor for a cooking device. The heat sensitive body B is composed of an inner case 17, a lid 16, a resin case 13 mounted in the inner case, a heat sensitive element 11 covered with an insulating protective tube 22 and a reed switch 14, and the heat sensitive body B is The heat sensitive body B is held by the outer case 18 via a coil spring 15, and can move up and down.

As shown in FIG. 4, a groove 31 is formed in the disk-shaped portion of the upper surface of the resin case 13, and the heat-sensitive element 11 is covered with a protective tube 22 having high heat resistance such as silicon resin.
Are set in the groove 31, and the lead wires on both sides thereof are electrically connected to the terminals 21a and 21b attached to the lower portion of the resin case 13 by means such as spot welding. A flange 32 is provided on the upper circumferential portion of the resin case 13, the flange 32 overlaps the outer peripheral portion of the inner case 17, and an aluminum lid 16 is covered to mechanically attach the peripheral portion of the lid 16 to the inner case 17. By caulking, the resin case 13 becomes the inner case 1
7 is fixed in the inside, and the thermosensitive element 11 is pressure-bonded to the vicinity of the center of the back surface of the lid 16 via the protective tube 22,
The heat collected by the lid 16 is conducted to the heat sensitive element 11 through the protective tube 22.

A reed switch 14 is installed in the lower portion of the resin case 13, while one is provided in the outer case 18.
A pair of magnet pedestals 19 and magnets 20 are arranged, and by these, a switch for detecting the upper and lower movements of the heat sensitive body B is configured to detect whether or not the detected body is mounted. The leads on both sides of the reed switch 14 are further electrically connected to the terminals 21a and 21b.

[0005]

In the conventional temperature sensor for a cooker, the heat-sensitive element 11 is covered with an insulating protective tube 22 made of silicon rubber or the like so as to be mechanically brought into close contact with the back surface of the lid 16. Therefore, since the protective tube 22 having a low thermal conductivity is interposed between the heat sensitive element 11 and the lid 16, the thermal response is inferior in the temperature detection of the inner pot bottom of the rice cooker which is the object to be heated. There was a problem.

[0006]

In order to solve the above-mentioned problem of thermal response, a heat sensitive element is mounted in an insulating heat collecting plate made of aluminum nitride having a high thermal conductivity, and By mechanically adhering the heat plate to the inner side of the lid by caulking between the resin case and the lid, the heat conduction from the heated body to the heat-sensitive element was significantly improved as compared with the conventional case.

[0007]

[Function] In the conventional structure, the heat conduction path from the object to be heated is the cover of the good thermal conductor → the protection tube → the heat sensitive element, and since the protection tube is a tube of heat-resistant silicone or the like with low heat conductivity, Although it hindered conduction, aluminum nitride has good insulation and thermal conductivity because the structure of the heat conduction path is made of a good thermal conductor cover → aluminum nitride heat collecting plate → thermal element Since it is excellent, the heat from the object to be heated is transferred to the heat-sensitive element without being hindered on the way, and the thermal response is remarkably improved.

[0008]

1 and 2 show an embodiment of a temperature sensor for a cooker according to the present invention. The heat sensitive body A includes an inner case 7, a resin case 3, a lid 6 made of aluminum, a heat sensitive element 1 arranged above the resin case 3, an insulating heat collecting plate 2 made of an aluminum nitride material, and a resin case 3. The reed switch 4 is held at the bottom of the.

The heat sensitive body A is housed in the outer case 8 by the guide claws 40 and the coil spring 5 provided at the lower part of the inner case 7, and can move up and down for a certain distance section.

A magnet pedestal 9 is attached to the bottom of the outer case 8.
Are placed on both sides of the magnet pedestal 9
0 is placed. The two left and right magnets are arranged so that the reed switch 4 is located in the middle of the two magnets, and the heat sensitive body A depends on whether or not there is a heated object (in the case of a rice cooker, the bottom of the inner tab). It moves up and down, and the contact of the reed switch changes between ON and OFF, so that the presence or absence of the detected object can be detected.

In the embodiment shown in FIG. 1, the insulating heat collecting plate 2 is made of aluminum nitride, which has the highest thermal conductivity among the insulating materials.

As a reference, when comparing its characteristics with that of conventionally used alumina, the thermal conductivity of aluminum nitride is 180 W · m.
^-1 · K ^-1 whereas normal alumina is about 21 W · m ^-1
• K ^-1 , and aluminum nitride has about eight times the thermal conductivity of alumina.

FIG. 2 is an assembly perspective view of the embodiment of FIG. 1, in which an insulating heat collecting plate 2 is composed of one sheet, and the bottom surface portion has substantially the same size as the outer shape of the heat sensitive element 1. Is formed so that the heat sensitive element 1 is recessed into the bottom surface of the heat collecting plate 2, while the upper surface portion of the resin case 3 is set so that the metal body of the heat collecting plate 2 is just fitted to the upper surface of the resin case. The concave portion is formed.

Due to the above-mentioned arrangement relationship of the respective parts, the heat-sensitive body A
In the assembled state, the relative positions of the parts are as shown in Fig. 1, and the insulating heat collecting plate 2 (material: aluminum nitride) is used.
The upper surface of the heat-sensitive element 1 is in close contact with the inner surface of the lid 6, and the outer peripheral surface of the upper portion of the heat-sensitive element 1 is in close contact with the recessed portion of the heat collecting plate 2. Therefore, the heat received by the lid 6 from the object to be detected is the heat collecting plate 2
Through the heat sensitive element 1.

In the conventional structure shown in FIG. 3, the path of heat conduction is in the order of the cover 16 of the good conductor of heat → the protective tube 22 → the thermosensitive element 11. Here, since the protective tube is a tube made of silicon or the like having good heat resistance, the thermal conduction is made. The rate was low, and therefore the thermal response in actual use was insufficient.

On the other hand, in the case of the structure of the present invention, the path of heat conduction is the cover 6 of the good thermal conductor → the heat collecting plate 2 (the material is aluminum nitride).
→ The heat-sensitive element 1 is arranged in this order, and the thermal conductivity of the heat collecting plate of the present invention is about one digit higher than that in the conventional case, so that the thermal response is significantly improved as compared with the conventional case.

Further, according to the present invention, the heat-sensitive element 1 does not need to be covered with a protective tube as in the prior art because the heat collecting plate 2 is insulative, and can be left naked, so that the whole process is simpler than in the prior art. There are advantages. As the heat sensitive element, a general one such as an NTC thermistor or a platinum film resistance element can be used.

[0018]

As described above, according to the present invention, it is possible to provide a temperature sensor for a cooking device which has a significantly improved thermal response as compared with a conventional temperature sensor for a cooking device and which has a reduced number of assembling steps.

[Brief description of drawings]

FIG. 1 shows an embodiment of a temperature sensor for a cooker according to the present invention.

FIG. 2 is an assembly perspective view of the embodiment of the present invention.

FIG. 3 is a front sectional view showing an example of a conventional temperature sensor for a cooking device.

FIG. 4 is an assembly perspective view of a conventional example.

[Explanation of symbols]

 1,11 Heat-sensitive element 2 Heat-collecting plate 3,13 Resin case 4,14 Reed switch 5,15 Coil spring 6,16 Lid 7,17 Inner case 8,18 Outer case 9,19 Magnet pedestal 10,20 Magnet 11a, 11b, 21a, 21b Terminal 22 Protective tube 30a, 30b Lead wire 31 Groove 32 Collar 40 Guide claw A Heat sensitive body (present invention) B Heat sensitive body (conventional example)

Claims (2)

[Claims] 1. A temperature sensor for a cooker, comprising a heat sensitive body for detecting whether or not a heated body is mounted and for detecting the temperature of the heated body, wherein a material of a heat collecting plate constituting the heat sensitive body is nitriding. A temperature sensor for a cooker, which is made of aluminum. 2. The heat collecting plate made of aluminum nitride according to claim 1 is closely fixed to a back surface of a lid attached to an upper portion of the heat sensitive body, and a concave portion is formed on a lower surface of the heat collecting plate. A temperature sensor for a cooker, wherein the heat-sensitive element is closely fixed to the recess.