JPS5833938Y2 - thermal response device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improved structure of a thermally responsive device used in a rice cooker or the like.

Conventional devices of this type are represented by FIGS. 1 and 2.

That is, 1 is a temperature sensing element such as ferrite facing the bottom of the pot,
2 is a vertically movable permanent magnet arranged opposite to the lower surface of this element 1; 3 is a holding plate that holds and interlocks this magnet 2;
Reference numeral 4 denotes an operating rod which is fixed to the holding plate 3 and controls a heating device (not shown) according to the vertical movement of the magnet 2, and 5 is a guide rod for smoothly moving the holding plate 3 up and down.

In addition, as shown in FIG. 2, the lower surface of the temperature sensing element 1 is covered with a protective plate 6 to protect the element from shock when it comes into contact with the magnet 2, and the magnet 2 is also protected from the shock at that time. In order to avoid this, U-shaped yoke plates 7 having upwardly bent pieces are provided on both sides.

The permanent magnet 2 has upper and lower surfaces formed as magnetic pole surfaces.

In this conventional device, in order to reliably detect the operation completion temperature of a rice cooker, etc., it is necessary to increase the attraction force of the permanent magnet 2, and for this purpose, if the magnetic pole surface is increased, the corresponding temperature sensing element 1 However, as the size of the device increases, the area to be heated by the rice cooker increases, resulting in uneven cooking.

Also, as can be seen from Figure 2, two magnetic circuits are created between the permanent magnet 2 and the temperature sensing element 1, so if you want to use a small temperature sensing element 1, you can use a small one as shown in Figure 3. I had to use two of these.

Furthermore, since the yoke plate 7 is integrally formed, it is difficult to bring the top ends of the bent pieces on both sides into close contact with the lower surface of the protection plate 6, and the gap between the yoke plate 7 and the lower surface creates magnetic resistance, causing an error in the response temperature. may occur.

Furthermore, when temperature sensing elements with different characteristics are used to detect the two response temperatures, it is impossible to avoid an increase in the size of the device, and it is not possible to prevent an increase in the heated range.

The present invention has been made to eliminate the above-mentioned drawbacks, and embodiments will be described below based on the drawings from FIG. 4 onwards.

Reference numeral 1 denotes a case of the main body of the device formed in the shape of a cylinder with an inverted bottom.A temperature sensing element 2 with sufficient impact strength is attached to the inner upper surface of the case with a metal fitting 3, and a pair of guide rods made of non-magnetic material are attached using this metal fitting 3. 4,4
is installed vertically.

Reference numeral 5 denotes a holding plate which is attached to the guide rods 4, 4 so as to be movable up and down, and an operating rod 6 for controlling a heating device (not shown) is fixed to the center of the holding plate.

Reference numeral 7 denotes a rectangular permanent magnet placed on the upper part of the holding plate 5, and both sides thereof are magnetized to serve as magnetic pole faces.

Reference numerals 8 and 8 denote yoke plates which are movably attracted to the magnetic pole faces of the magnet 7, and have notches 9, 9 formed in the center of their upper ends, and whose upper end faces 10 and 10 protrude above the magnet 7. and is made to face the lower surface of the temperature sensing element 2.

Reference numeral 11 denotes a fixing plate mainly composed of opposing upward side pieces 12 and 12 fixed to both sides of the holding plate 5;
The magnet 7 and a pair of yoke plates 8.8 are movably arranged between the magnets 12, and surrounding pieces 13 facing each other are bent at the side ends of the side pieces 12, 12. A cover piece 14 is bent at the upper end of the side pieces 12, 12 to cover the upper part of the magnet 7 between the yoke plates 8, 8.
Horizontal projecting pieces 15, 15 are formed protrudingly in the middle of this cover piece 14 and are positioned within the notches 9.9 of the yoke plates 8, 8.

A gap is formed between the side pieces 12, 12 and the surrounding piece 13, and the magnet 7 and the pair of yoke plates 8, 8 to allow the movement of the magnet, etc. , 15 and the notches 9, 9 are also formed with similar gaps.

When the heating device is activated, the operating rod 6 moves in conjunction with the holding plate 5, the fixed plate 1L, the magnet 7, and the pair of yoke plates 8, 8.
the upper end surfaces 10.10 of the pair of yoke plates 8, 8.
. . . is brought into contact with the lower surface of the temperature sensing element 2.

At this time, since the yoke plates 8, 8 are movable, their upper end surfaces 1
The entire area of 0.10... is brought into contact with the lower surface of the element.

Due to this contact, a magnetic circuit with no air gap resistance is formed between the temperature sensing element 2 and the magnet 7 via the yoke plates 8, 8, and the upper end surfaces 10, 10, . . . of the yoke plates 8, 8 are formed. is reliably adsorbed to the temperature sensing element 2.

This adsorption maintains the operating rod 6 and allows the heating device to be used continuously.

Next, when the heating progresses and reaches a predetermined heating temperature, the temperature sensing element 2 lowers its magnetic permeability and the attraction force of the yoke plate 8.8.

Then, the operating rod 6, which has been biased in the downward direction in advance, descends together with the holding plate 5 and the like.

Therefore, the heating device also stops. In this way, the thermal response device according to the present invention has both sides of the magnet formed as magnetic pole faces, a yoke plate is attached to each side, and the top end of the yoke plate is made to face one side of the temperature sensing element to form a magnetic circuit. Because of this, the device does not become larger in the lateral direction, and the area to be heated can be prevented from increasing.

Further, even when a plurality of devices are installed, since there is sufficient space for installation, it is possible to install a plurality of devices without significantly increasing the range to be heated.

Furthermore, since a pair of yoke plates are movably attached to each magnetic pole surface, when the top of the yoke plate faces one surface of the heat-sensitive element, the top can contact that surface over the entire area, creating a magnetic circuit with low magnetic resistance. Since the adsorption is reliable, errors in response temperature are less likely to occur.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of the conventional example, Fig. 2 is a side sectional view of the main part thereof, Fig. 3 is a side sectional view of the main part of another conventional example, and Fig. 4 is a side sectional view of the main part of the conventional example.
5 is a front sectional view of the device of the present invention, FIG. 5 is a cutaway front view thereof, FIG. 6 is a side sectional view thereof, and FIG. 7 is an enlarged perspective view of the main parts. 2...Temperature sensing element, 7...Permanent magnet, 8
... Yoke plate, 10 ... Upper end surface, 12
...Fixed plate.

Claims (2)

[Scope of utility model registration request] (1) A device that controls a heating device by moving the magnet, which consists of a temperature-sensitive element whose magnetic permeability changes depending on the heat-receiving temperature and a permanent magnet placed opposite to one side of the element.
4. Magnetize both sides of the magnet, attach yoke plates to each side, and form a magnetic path by making the top ends of the pair of yoke plates face one side of the temperature-sensitive element. A thermal response device characterized by: (2) Utility model registration claim 1, characterized in that the yoke plate is slidably attracted to both sides of a permanent magnet.
Thermal response device described in section.