JPH10189233A - Inductive heating cooking utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductive heating cooking utensil capable of improving thermal response of a heat reception sensor and reducing a heating output quickly when an abnormal temperature rise occurs with a heated material. SOLUTION: A heat sensing element 14 is membrane-shaped, brought into contact with a top plate 2 that is a heating face and improves thermal response of a heat reception sensor 12, the heat reception sensor 12 improves performance for detecting a temperature rise of a heated material 10, and therefor the heat reception sensor 12 detects when an abnormal temperature rise occurs with the heat reception sensor immediately, a driving circuit 11 reduces a heating output, and safety can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to temperature control of an induction heating cooker.

[0002]

2. Description of the Related Art A conventional induction heating cooker has a configuration as shown in FIGS. That is, a top plate 2 made of a heat-resistant material that forms a heating surface is attached to the upper surface of the main body 1, and a heating coil 3 wound in a spiral shape is provided below the top plate 2. Is provided with a drive circuit 4 for supplying electricity for generating an induction magnetic field to the heating coil 3. Since many heat-generating components are attached to the drive circuit 4, a cooling fan 5 for blowing air to those components is provided near the drive circuit 4. Reference numeral 6 denotes a heat receiving sensor, which is formed of an insulating material such as a synthetic resin, and has a small cylindrical heat-sensitive element 7 embedded in the upper surface. The upper surface of the heat receiving sensor 6 is pushed up and fixed by the coil spring 8 so as to contact the lower surface of the top plate 2 near the center of the heating coil 3. The thermal element 7 and the drive circuit 4 are electrically connected by a connection line 9. An object to be heated 10 such as a pan can be placed on the upper surface of the top plate 2 and can be induction heated by a magnetic field generated from the heating coil 3.

[0003]

However, in the conventional structure as described above, when heat is transmitted from the top plate 2 forming the heating surface to the thermosensitive element 7 as shown by arrows a and b in FIG. In the state where the small cylindrical heat-sensitive element 7 is embedded in the heat-receiving sensor 6, the top plate 2
The direct path (arrow a) to the heat-sensitive element 7 is hard to conduct heat due to line contact, and the indirect path (arrow b) through the groove of the heat-receiving sensor 6 passes through the resin part of the heat-receiving sensor 6 so that heat is not generated. Difficult to conduct, both paths are top plate 2
From the heat to the heat-sensitive element 7. Therefore, when the object to be heated 10 is abnormally heated by the baking or the like and becomes a high temperature,
The high-temperature state is detected by the thermal element 7 via the top plate 2, and the drive circuit 4 performs control to reduce the heating output. However, the temperature of the heat-receiving sensor 6 is low because heat is not easily transmitted to the thermal element 7. It was necessary to perform safety control to reduce the heating output from the state. For this reason, when performing high-temperature cooking even under normal conditions, the above-described safety control is easily operated, and as a result, there has been a problem that the heating output is reduced during high-temperature cooking.

[0004] The present invention is to solve such a conventional problem, and improves the thermal response of the heat receiving sensor, increases the heating output in high-temperature cooking, and sets the object to be heated to an abnormally high temperature. It is an object of the present invention to provide an induction heating cooker that can quickly reduce the heating output when it becomes necessary.

[0005]

In order to solve the above-mentioned problems, the present invention provides a flat part on an upper surface of a heat receiving sensor, and fixes a thin plate or film-shaped thermosensitive element on the flat part, By contacting the flat part of the heat-receiving sensor inside, the contact area between the heating surface and the heat-sensitive element is increased, and the heat capacity per contact area of the heat-sensitive element is reduced. The transmission, that is, the thermal responsiveness can be improved.

[0006]

The invention according to claim 1 of the present invention is characterized in that a heating surface is provided on an upper portion of a main body of an induction heating cooker, and a heating coil wound in a spiral shape is provided below the heating surface. A drive circuit that controls the energization of the sensor is attached, a thin-plate or film-shaped heat-sensitive element is fixed to the flat part provided on the top of the heat-receiving sensor, and the connection lines of the heat-receiving sensor are connected to both ends of the heat-sensitive element, and the connection line is connected to the drive circuit , And one or a plurality of heat receiving sensors may be brought into contact with the flat portion on the upper surface to contact the inside of the heating surface. By making the heat-sensitive element into a flat thin plate or film and making contact with the heating surface, it is possible to increase the contact area between the heating surface and the heat-receiving element of the heat-receiving sensor and to reduce the heat capacity per contact area of the heat-sensitive element. And the thermal responsiveness can be improved. Therefore, the performance of the heat receiving sensor to detect the temperature rise of the object to be heated is improved, and when the object to be heated becomes abnormally high due to baking or the like, the heat receiving sensor immediately detects the abnormally high temperature and drives it. The heating output from the circuit can be reduced to ensure safety. In addition, as described above, since an abnormally high temperature of the object to be heated can be immediately detected, it is not necessary to perform safety control to lower the heating output in advance when the temperature of the heat receiving sensor rises to some extent. The heating output is no longer suppressed.

The invention according to claim 2 of the present invention can be implemented by providing a heat receiving sensor at a position extending from the vicinity of the center of the heating coil to the vicinity of the outer periphery thereof, and bringing the flat portion of the upper surface of the heat receiving sensor into contact with the inside of the heating surface. . The strong magnetic field generated from the heating coil exists near the center of the radius of the spirally wound heating coil. Therefore, the temperature rise of the object to be heated is highest near the center of the radius of the heating coil. In the present invention, the heat receiving sensor is provided mainly on the portion where the temperature of the object to be heated is large, and the temperature detecting performance of the heat receiving sensor can be further improved. Further, when the bottom surface of the object to be heated has a poor heat conduction due to a thin plate or the like, the temperature of the bottom surface of the object to be heated corresponding to the vicinity of the center of the radius of the heating coil at the time of abnormal heating is extremely increased. In the configuration, since the heat receiving sensor is provided at that location, the state can be immediately detected, and the heating output can be reduced.

According to a third aspect of the present invention, a plurality of thermal elements are provided in a thermal sensor, the thermal elements are arranged in the longitudinal direction of the thermal sensor, and electrically parallel to both ends of each thermal element. However, it can be implemented by connecting each to a drive circuit. If the bottom surface of the object to be heated has irregularities, heat is easily transmitted from the contact portion between the bottom surface and the heating surface to the heat receiving sensor. However, this contact portion is not constant depending on the state of the bottom surface of the object to be heated and the position where the object to be heated is placed. Therefore, by lengthening the heat receiving sensor, arranging the heat sensitive elements in the longitudinal direction, and connecting the output of each heat sensitive element to the drive circuit in parallel, the state of the bottom surface of the object to be heated and the position of the object to be heated can be Even if the contact portion changes, the drive circuit can control the heating output of the object to be heated by using the thermosensitive element which is always in the best sensing state.

[0009]

【Example】

(Embodiment 1) In FIGS. 1 and 2, 1 is a main body, 2 is a top plate forming a heating surface, 3 is a heating coil, 5 is a cooling fan, 10 is an object to be heated such as a pan, and the above is a conventional example. Since the configuration is the same as that of FIG. A driving circuit 11 supplies electricity for generating an induction magnetic field to the heating coil 3. A heat receiving sensor 12 has a support plate 13 made of, for example, alumina or the like mounted on the upper surface, and a film-shaped heat-sensitive element 14 made of, for example, platinum is fixed on the support plate 13. The upper surface of the heat receiving sensor 12 is pushed up and fixed by a coil spring 15 so as to contact the lower surface of the top plate 2 near the center of the heating coil 3. The heat-sensitive element 14 and the drive circuit 11 are electrically connected by a connection line 16. An object to be heated 10 such as a pan can be placed on the upper surface of the top plate 2 and can be induction heated by a magnetic field generated from the heating coil 3.

Next, the operation of this embodiment will be described. If the food 10 such as a pot is baked by mistake without putting the food therein, the temperature of the food 10 becomes abnormally high. Therefore,
The temperature of the object to be heated 10 is detected by the thermal element 14 of the heat receiving sensor 12 via the top plate 2 forming the heating surface,
When the temperature of the heat-sensitive element 14 exceeds a predetermined temperature, the drive circuit 11 reduces or stops the power transmission to the heating coil 3, thereby suppressing an abnormally high temperature due to the burning of the object 10 to be heated.
In the present embodiment, the heat-sensitive element 14 is formed into a flat film and is brought into contact with the top plate 2 forming the heating surface, so that the contact area between the heating surface and the heat-sensitive element 14 is increased, and the contact area per heat-sensitive element 14 The heat capacity can be reduced, and the thermal responsiveness can be improved. Therefore, the performance of the heat receiving sensor 12 detecting the temperature rise of the object to be heated 10 is improved. For example, FIG. 3 shows the difference in the perceived temperature between the conventional example and the present embodiment in the case where the object to be heated 10 is empty-baked and the case where a stir-fry is used as high-temperature cooking. It can be seen that the temperature detection of the heat receiving sensor 12 is good both in baking and in stir-fry. Further, when the temperature of the object to be heated 10 reaches the heating stop temperature level, each of the heat receiving sensors 6, 1
Comparing the temperature of 2, the conventional heat receiving sensor 6 has a small temperature difference between the empty baking and the stir-fry, and the heat receiving sensor 12 in the embodiment of the present invention has a large temperature difference between the empty baking and the stir-fry. I understand. In the conventional example, it is difficult to judge between the time of the empty baking and the time of the stir-fry, and the safety control is performed so that the heating output is previously reduced when the temperature of the heat receiving sensor 6 rises to some extent. Since it is possible to sufficiently judge the time and the time of the stir-fry, the heating output can be reduced during the empty baking, and sufficient heating output can be controlled during the high-temperature cooking of the stir-fry or the like.

(Embodiment 2) In FIGS. 4 and 5, reference numeral 2 denotes a top plate forming a heating surface, 3 denotes a heating coil,
Is an object to be heated such as a pot. A heat receiving sensor 17 has a support plate 18 attached to the upper surface, and a film-like heat-sensitive element 19 is fixed on the support plate 18. The heat receiving sensor 17 is pushed up and fixed by the coil springs 20a and 20b so as to extend over the heating coil 3 from the vicinity of the center to the vicinity of the outer periphery and to contact the lower surface of the top plate 2. The thermal element 19 and the drive circuit (not shown) are connected to the connection line 2
1 electrically connected.

Next, the operation of this embodiment will be described. The strong magnetic field generated from the heating coil 3 exists near the center of the radius of the spirally wound heating coil 3.
Therefore, as shown in FIG.
Is highest near the center of the radius of the heating coil 3. In the present invention, the heat receiving sensor 17 is provided mainly on a portion where the temperature of the object to be heated 10 is large, and the temperature detecting performance of the heat receiving sensor 17 can be further improved.

(Embodiment 3) In FIGS. 6 and 7, reference numeral 2 denotes a top plate forming a heating surface, and reference numeral 3 denotes a heating coil. Reference numeral 22 denotes a heat receiving sensor, on which a support plate 23 is attached on the upper surface, and a plurality of film-like heat-sensitive elements 24a to 24-2 are mounted on the support plate 23.
4e is fixed. The heat receiving sensor 22 is positioned over the heating coil 3 from the vicinity of the center to the vicinity of the outer periphery, and is in contact with the lower surface of the top plate 2.
It is pushed up and fixed by the coil springs 25a and 25b. The heat-sensitive elements 24a to 24e and a drive circuit (not shown) are electrically connected in parallel by a connection line 26. Reference numeral 27 denotes an object to be heated such as a pan having an uneven bottom surface.

Next, the operation of this embodiment will be described. If the bottom surface of the object to be heated 27 has irregularities, heat is easily transmitted to the heat receiving sensor 22 from the contact portion 28 between the bottom surface and the top plate 2 forming the heating surface, as shown by the arrow c in FIG. However, the contact portion 28 is not constant depending on the state of the bottom surface of the heated object 27 or the position where the heated object 27 is placed. Therefore, in the present embodiment, the heat receiving sensor 22 is lengthened, and the heat sensitive elements 24a to 24e are arranged in the longitudinal direction.
By connecting the output of 4e to the drive circuit in parallel, even if the way of transmitting heat to the heat receiving sensor 22 changes depending on the state of the bottom surface of the object to be heated 27, the position of the object to be heated 27, etc. The drive circuit can always select the heat-sensitive element having the highest temperature from among the heat-sensitive elements having the highest temperature among the heat-sensitive elements 24e to control the heating output of the object to be heated 27. Performance can be improved.

In each of the embodiments, the heat-sensitive element is formed on the support plate in the form of a film. However, the heat-sensitive element may be formed in a thin plate and mounted directly on the heat-receiving sensor.

[0016]

According to the induction heating cooker of the first aspect of the present invention, the heat responsiveness of the heat receiving sensor can be improved.
Therefore, when the object to be heated has an abnormally high temperature due to baking or the like, the heat receiving sensor immediately detects the abnormally high temperature, reduces the heating output from the drive circuit, and can ensure safety. Further, as described above, since an abnormally high temperature of the object to be heated can be immediately detected, it is not necessary for the heat receiving sensor to perform safety control to reduce the heating output in advance when the temperature rises to some extent. In this case, the heating output is not suppressed.

The induction heating cooker according to the second aspect of the present invention comprises:
By arranging the heat receiving sensor at the position where the temperature of the object to be heated is highest, abnormal heating can be detected even when the bottom surface of the object to be heated is poor, such as a thin plate, and the heating output can be reduced.

According to a third aspect of the present invention, there is provided an induction heating cooker comprising:
Even when the bottom surface of the object to be heated has irregularities, the abnormally high temperature of the object to be heated can be stably detected, and the heating output can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an induction heating cooker according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a heat receiving sensor of the induction heating cooker.

FIG. 3 is a diagram showing the difference in the temperature perceived by the heat receiving sensor between the first embodiment of the present invention and the conventional example.

FIG. 4 is a sectional view of a main part of an induction heating cooker according to a second embodiment of the present invention.

FIG. 5 is a top view of a heat receiving sensor of the induction heating cooker.

FIG. 6 is a sectional view of a main part of an induction heating cooker according to a third embodiment of the present invention.

FIG. 7 is a top view of a heat receiving sensor of the induction heating cooker.

FIG. 8 is a sectional view of a conventional induction heating cooker.

FIG. 9 is a perspective view of a heat receiving sensor of the induction heating cooker.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main body 2 Top plate 3 Heating coil 11 Drive circuit 12, 17, 22 Heat-receiving sensor 14, 19, 24a, 24b, 24c, 24d, 24e
Thermal element 16, 21, 26 Connecting wire

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tamotsu Izumaya 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Koichi Hosoi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A heating surface provided on an upper portion of a main body, a heating coil spirally wound below the heating surface, a drive circuit for controlling energization of the heating coil, a heat receiving sensor having a flat portion on an upper surface, A thin-plate or film-shaped heat-sensitive element fixed to the flat portion, connecting a connection line of a heat-receiving sensor to both ends of the heat-sensitive element, electrically connecting the connection line to a drive circuit, and connecting one or more An induction heating cooker in which the flat part on the upper surface of each heat receiving sensor is in contact with the inside of the heating surface. 2. The induction heating cooker according to claim 1, wherein the heat receiving sensor is provided at a position extending from the vicinity of the center of the heating coil to the vicinity of the outer periphery thereof, and the flat portion of the upper surface of the heat receiving sensor is brought into contact with the inside of the heating surface. 3. The induction heating cooker according to claim 1, wherein heat-sensitive elements are arranged in the longitudinal direction of the heat-receiving sensor, electrically arranged in parallel at both ends of each of the heat-sensitive elements, and drive circuits are respectively connected.