JPH07102177B2 - Overheating prevention device for cookware - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing overheating of cookware such as rice cookers.

2. Description of the Related Art In recent years, for example, in rice cookers, in order to improve the rice cooking performance and shorten the rice cooking time, many rice cookers have a high power consumption of a heater. For this reason, in order to ensure the safety of the appliances, the overheating prevention device of this type of rice cooker is mainly one that stops or restricts energization by detecting an abnormal temperature of the heater with a temperature fuse or a safety sensor, for example. Was becoming.

The configuration will be described below with reference to FIG.

As shown in the figure, a protective frame 3 supporting a heater 2 is attached to the main body 1. A temperature sensor 4 that operates by detecting the temperature of the bottom of the pot is provided at the center of the heater 2, and the pot 5 is placed on the heater 2. A thermal fuse 6 is attached to the protective frame 3. Below the protective frame 3 is a control board 7, which is covered by a back plate 8 provided with holes for cooling.

In the above configuration, if a failure occurs in the temperature sensor 4 or the control board 7, the heater 2 and the pan 5 are heated above the set temperature, and the temperature rises abnormally. The temperature fuse 6 detects the temperature rise and stops the input to the heater 2.

However, in such a conventional rice cooker, since the temperature fuse 6 is attached to the protective frame 3, the inflowing air or room temperature through the air vent holes provided in the back plate 8 or the like. It was difficult to follow the rapid temperature rise of the heater 2 sufficiently quickly. For this reason, the temperature of the heater 2 rises abnormally before the thermal fuse 6 operates, and the heater 2 may be deformed or melted so that it cannot be reused. Further, since the temperature sensor 4 and the temperature fuse 6 are individually provided in different places, the number of parts and the number of assembling steps are increased, resulting in a high cost.

The present invention solves the above problem, and an object of the present invention is to provide a rice cooker that can stop energization of the heater without causing danger even when the temperature of the heater rises abnormally.

Means for Solving the Problems To achieve the above object, the first means for solving the problems of the present invention is a heater for heating the bottom of a pot, and a central portion of the heater is supported by a spring so as to be pressed against the bottom of the pot. A thermosensitive member disposed on the top of the case and abutting on the bottom of the pan; and a thermal fuse unit disposed inside the case, wherein the thermosensitive member includes a temperature plate and a temperature plate abutting on the bottom of the pan. It is composed of a pan sensor for detecting the pan bottom temperature via a pan and a pan-shaped fixing plate that presses the pan sensor at the bottom to the temperature-sensitive plate and adheres to the temperature-sensitive plate at the edge, and at the bottom of the fixed plate, A protrusion is provided below the non-pressure contact portion of the pan sensor, and the temperature fuse unit of the temperature fuse unit is in contact with the protrusion.

A second means for solving the problem is that the thermal fuse unit is bent in a substantially U-shape, and the thermal fuse lead wire portion is brought into contact with the protruding portion.

Function In the configuration of the first problem solving means, when the temperature sensor or the control board fails for some reason and the temperature of the heater rises abnormally, the heat of the heater is transmitted to the bottom of the pot and the heat contacts the bottom of the pot. The heat is transmitted to the heat-sensitive member, and the heat is transmitted to the thermal fuse that is in contact with the heat-sensitive member, and the temperature of the thermal fuse rapidly rises to interrupt the current. Also, since the temperature fuse part is arranged under the pan sensor via the fixing plate, it can be efficiently stored in the inner case even when the area of the temperature sensing plate is relatively small. Since the temperature fuse part is in contact with the protruding part provided at the end, a gap is created between the pan sensor and the temperature fuse part as a result, so heat from the temperature fuse part and conversely heat of the fixing plate are needed more than necessary. It is possible to prevent the heat detection accuracy of the pan sensor from being deteriorated due to the stuffiness of the pan.

Therefore, the energization of the heater is stopped and the temperature rise is suppressed. Moreover, since the temperature fuse is provided inside the case, it is not easily affected by outside air or room temperature, and stable operation can be performed.

The second problem solving means is effective when the space in the case cannot be sufficiently secured and it cannot be attached to the thermal fuse heat-sensitive member. That is, instead of the thermal fuse portion, the lead wire portion is brought into contact with the protruding portion of the fixing plate, and the thermal fuse is operated by the heat transferred from the lead wire.
Therefore, the first effect can be obtained even in the case where the inner diameter is equal to or less than the length of the thermal fuse.

Example Hereinafter, a rice cooker according to an example of the present invention will be described with reference to FIGS. 1, 2, 3, and 4.

As shown in FIG. 4, a protective frame 13 to which a heater 11 such as a cast-in heater is fixed is attached to the main body 10. A temperature detection device 14 is provided at the center of the heater 11,
The pot 15 is placed on the heater 11. One end of the lid 16 is rotatably supported on the upper portion of the main body 10. Further, the operation display unit 17 is attached to the side surface of the main body 10. A control board 18 is arranged under the protective frame 13 and is covered with a back plate 19. FIG. 1 is a cross-sectional view of the temperature detecting device 14. The outer case 20 is fixed to the heater 11, and the inner case 21 is supported by the outer case 20 by a spring 22 so as to be pressed against the bottom surface of the pan 15. Pan sensor 23 that detects the temperature of the bottom of the pan 15
Is sandwiched between the temperature-sensitive plate 24 and the bottom of the recess of a plate-shaped fixing plate 25, and the edge of the plate is in close contact with the temperature-sensitive plate 24 to form a heat-sensitive member, which is fixed to the upper part of the inner case 21.

The temperature fuse unit 26 for detecting an abnormal temperature rise of the heater 11 is bent in a substantially U shape, and the temperature fuse 27 is contacted with the protruding portion 25a provided below the non-pressure contact portion of the pan sensor 23 at the bottom of the concave portion of the fixing plate 25. Claw 21a of inner case 21 and fixing plate 2
It is sandwiched and fixed between the five.

Next, the embodiment shown in FIG. 2 shows a case where the inner case 21 has a relatively small inner diameter so that the structure shown in FIG. 1 cannot be performed.

That is, as shown in the figure, the thermal fuse unit 26 is bent into a substantially U shape, and the protruding portion 25 provided below the fixing plate 25 is provided.
Inner case 2 so that the thermal fuse lead wire part 28 contacts a
It is sandwiched and fixed between the first claw 21a and the fixed plate 25.

Further, the embodiment according to FIG. 3 shows a rice cooker having a structure in which the pot is heated by magnetic induction heating using the coil 29 instead of the above-mentioned casting type heater 11 or the like.

With the above configuration, if the pan sensor 23 or the control board 18 fails for some reason and the bottom surface of the pan 15 reaches the set temperature, the temperature of the heater 11 rises abnormally when the heater 11 is continuously energized. Therefore, the heat of the heater 11 is transmitted to the bottom surface of the pot 15, and the heat is applied to the heat sensitive plate 24, which is in contact with the bottom surface of the pot 15.
The thermal fuse 27, which is transmitted to the fixed plate 25 and comes into contact with the protruding portion 25a of the fixed plate 25 as a result, receives heat and abruptly rises in temperature to interrupt the current. Therefore, the energization of the heater 11 is stopped and the temperature rise is suppressed. Moreover, since the thermal fuse 27 is provided in the inner case 21, it is less likely to be affected by outside air or room temperature, and stable operation can be performed.

Further, according to the overheat prevention device of the rice cooker of the embodiment shown in FIG. 2, the heat transferred from the bottom surface of the pan 15 to the heat sensitive plate 24 and the fixed plate 25 is brought into contact with the protruding portion 25a of the fixed plate 25. The temperature fuse 27 is transmitted to the temperature fuse lead wire portion 28 and is transmitted to the temperature fuse 27. As a result, the temperature fuse 27 rises in temperature and shuts off the current, so that energization to the heater 11 is stopped and an abnormal temperature rise is prevented. According to this configuration, the heat transfer is slightly deteriorated due to the thermal fuse lead wire 28, but in this case, the temperature detected by the thermal fuse 27 may be set to a high value in advance so long as the performance is not adversely affected.

Further, according to the overheat prevention device attached to the rice cooker of the embodiment shown in FIG. 3, since the pan 15 itself is directly heated by the magnetic induction heating by the coil 29, the heat sensitive plate 24, the fixed plate 2
Since the heat transfer to 5 is quick and the followability of the thermal fuse 27 is improved, the temperature detecting action when the temperature of the rice cooker shown in FIGS. 1 and 2 is excessively increased is further promoted, and the safety and stability are further improved. The operation of the thermal fuse can be obtained.

EFFECTS OF THE INVENTION As is clear from the description of the above embodiments, since the present invention is configured such that the thermal fuse is attached to the heat-sensitive member of the case that abuts on the bottom of the pan, the pan sensor or the control board fails for some reason and the heater If the temperature rises abnormally, the temperature fuse inside the case located in the center of the heater immediately senses the abnormal temperature rise of the pan from the heat-sensitive member and operates to stop the energization of the heater to prevent overheating. The danger of deformation, melting, or fire of the heater or other parts can be prevented in advance. In addition, since the temperature fuse part is placed under the pan sensor via the fixing plate, it can be efficiently stored in the inner case even when the area of the temperature sensing plate is relatively small. Since the temperature fuse part is in contact with the protruding part provided, a gap is created between the pan sensor and the temperature fuse part as a result, so that heat from the temperature fuse part and conversely heat of the fixing plate are exceeded. It is possible to prevent a decrease in the heat detection accuracy of the pan sensor due to being exposed.

Also, by bending the temperature fuse unit into a substantially U shape and detecting an abnormal temperature rise of the pan from the heat sensitive member via the temperature fuse lead wire portion, it becomes possible to configure in a small case where the temperature fuse does not fit. .

Furthermore, by using induction heating with a coil as the means for heating the pot, the overheat prevention device of the present invention can detect the temperature of the pot more quickly, and can achieve safer and more stable operation.

Since the overheat detection unit is built in the inner case with the pan sensor in this way, it is possible to provide an inexpensive overheat prevention device for cooking utensils that not only improves the overheat prevention performance but also reduces the number of parts. .

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a rice cooker according to an embodiment of the present invention,
The figure is a cross-sectional view of a main part of another embodiment, FIG. 3 is a partially cutaway side view of a rice cooker of another embodiment, FIG. 4 is a partially cutaway front view of a rice cooker, and FIG. It is a partially cutaway side view of the rice cooker. 11 …… heater, 15 …… pan, 21 …… inner case (case),
22 …… Spring, 25 …… Fixing plate, 25a …… Projection, 26 …… Thermal fuse unit, 27 …… Thermal fuse, 28 …… Thermal fuse lead wire.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masafumi Kubo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kenji Kinoshita 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Toshio Arai 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 62-161318 (JP, A) JP 60-119912 (JP, A) JP Hei 2-147013 (JP, A)

Claims (2)

[Claims] 1. A heater for heating the bottom of the pan, a case supported by a spring in the center of the heater so as to be pressed against the bottom of the pan, a heat-sensitive member disposed above the case and abutting the bottom of the pan, and the case. A temperature fuse unit disposed inside, the heat sensitive member is a temperature sensitive plate abutting on the bottom of the pan and a pan sensor for detecting the temperature of the pan bottom through the temperature sensitive plate and a pan sensor at the bottom to the temperature sensitive plate. It is composed of a plate-shaped fixing plate that is pressed against and is in close contact with the temperature-sensitive plate at the edge, and the bottom part of the fixing plate is provided with a protruding part below the non-press-contact part of the pan sensor, and the temperature of the temperature fuse unit A device for preventing overheating of a cooking utensil, wherein a fuse portion is in contact with the protruding portion. 2. The overheating prevention device for a cooking utensil according to claim 1, wherein the temperature fuse unit is bent into a substantially U shape, and the temperature fuse lead wire portion is in contact with the protruding portion.