JPS58836B2 - induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to thermal protection of a heating coil in an induction heating cooker, and an object of the present invention is to cool the heating coil using a heat insulating material without using a fan.

Conventionally, the heating coil of an induction heating cooker has a configuration in which a gap is provided between the top plate and the heating coil, and the heating coil is forcedly cooled by a cooling fan.

This is because the heating coil is made of litz wire to increase the heating efficiency of the entire cooker, and it is a means to ensure that the pot being heated satisfies the heat resistance tolerance of the insulation coating of the litz wire during air conditioning, etc. there were.

However, performing forced air cooling using a cooling fan in this manner imposes significant limitations on the overall structure and cost of the cooking device, and has been an obstacle to downsizing the device.

The present invention is intended to solve the above-mentioned drawbacks, and by disposing a heat insulating material between the top plate and the heating coil, and disposing an overtemperature rise prevention device between the heating coil and the heat insulating material. This achieves a configuration that satisfies the heat resistance tolerance of a heating coil made of litz wire without forced air cooling of the heating coil.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, a coil 1 is bonded to a support substrate 2 with impregnated varnish.

The heating coil 1 uses interline insulation (not shown) to obtain a predetermined outer shape.

The ferrite cores 3 are arranged radially from the center of the heating coil 1 and placed on the support substrate 2 so that the magnetic flux from the heating coil 1 does not affect the high frequency power supply section (not shown) arranged below. ing.

The top plate 4 is designed so that a pot can be placed thereon.

A flexible heat insulating material 5 is placed between the top plate 4 and the heating coil 1.

The aluminum plate 6 is used as a heat conduction plate,
A temperature sensitive switch 7 is arranged at the end.

8 is an insulating paper for insulating the aluminum plate 6 and the heating coil 1, and 9 is a pot switch magnet.

In this configuration, assuming that a high frequency power supply section is disposed at the bottom of the board 2 and a cooling fan is cooling the high frequency power supply section, the temperature of the heating coil 1 is determined by the self-heating amount of the heating coil 1, the amount of heat generated by the top plate 4, and the temperature of the heating coil 1. It is thought that this is determined by three factors: radiant and conductive heat from the pan during air conditioning, and heat dissipation from the bottom of the board 2.

Conventionally, among these three factors, radiant and conductive heat from the pot,
Without separating the two causes of self-heating of the heating coil 1, forced cooling was simply performed even in the event of an abnormality during air conditioning.

In the configuration of the present invention, the top plate 4 is
This innovative design reduces radiation and conduction heat from the upper pot, cools the self-generated heat of the heating coil 1 from the lower part of the board 2 under normal conditions, and protects it with an overtemperature rise prevention device in the event of an abnormality such as air conditioning. The concept made it possible to separate the two heat generation sources, and succeeded in greatly simplifying the configuration of the heating coil section, which until now required a complicated cooling configuration.

This configuration can also be said to be very effective in reducing radiation and conduction heat from the pot to the high frequency power supply section.

Furthermore, since the distance of the conventional ferrite core 3 from the heating coil 1 is one curie point of the ferrite core 3,
Although I could not get it very close to heating coil 1,
In the configuration of the present invention, it is possible to bond directly to the substrate 2.

Furthermore, the temperature overrise prevention device is placed between the heat insulating material 5 and the heating coil 1, as shown in FIG. Due to the unavoidable configuration, it is highly effective in reducing and equalizing the influence of the pan temperature on the heating coil in terms of the performance of over-temperature rise protection when the relative position of the pan is shifted with respect to the heating coil 1. .

To explain Fig. 2 here, 1 is the heating coil position, 6
10 is the position of the aluminum plate, 10 is the position of the cooling fan of the high frequency power supply section, and the shaded part b is the position of the bottom of the pot.

In theory, insulation materials do not conduct heat, but in reality they do.

In addition, with air conditioning, the temperature at the bottom of the pot does not rise on average, but may locally reach a high temperature of 350 to 450 degrees Celsius due to warping of the bottom of the pot, and in this case, if there is no insulation, the top plate made of ceramic etc. permeates and locally heats the surface of the heating coil to 300°C or higher.

In such a state, overheat protection over the entire surface of the heating coil is required.

In order to cover the above points, the present invention inserts a heat insulating material between the heating coil and the top plate, cuts the radiant heat as described above, and detects the average temperature of the heat insulating material, which increases due to conductive heat. This protects the heating coil.

During steady oscillation, the heating coil is at 140 to 150°C.
When the air conditioning was on, the temperature reached around 200°C, confirming that there were no malfunctions.

As explained above, the present invention solves the thermal configuration of the heating coil section, which has conventionally been a major bottleneck in terms of the configuration, such as making the device compact as a cooking device, by matching the shape and thickness of the heat insulating material 5 and the substrate 2. This was easily achieved by
Furthermore, by adding a temperature overrise prevention device, the configuration is such that the heat resistance tolerance of the heating coil 1 can be fully satisfied even under abnormal conditions such as during air conditioning.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of a main part of an induction heating cooker according to an embodiment of the present invention, and FIGS. 2a and 2b are plan views thereof. 1... Heating coil, 2... Support substrate,
4...Top plate, 5...Insulation board, 6...Aluminum backing plate, 7...
...Thermosensitive switch, 8...Insulating paper.

Claims (1)

[Scope of Claims] A top plate on which a pot is placed; a heating coil disposed below the top plate for inductively heating the pot; a support substrate supporting the heating coil; the top plate and the heating coil; An induction device comprising: a heat insulating material disposed between the heating coil and the heat insulating material to block radiant heat from the pot; and a temperature overrise prevention device disposed between the heating coil and the heat insulating material to detect an averaged temperature of the heat insulating material. Heating cooker. 2. The above-mentioned excessive temperature rise prevention device is comprised of a heat conductive plate made of a highly dielectric metal and a temperature-sensitive switch.
Induction heating cooker as described in section. 3. The induction heating coil section further includes a high-frequency power supply section that supplies a high-frequency current to the induction heating coil section, a cooling fan that forcibly cools the high-frequency power supply section, and a pot detection device, and the overtemperature rise prevention device is combined with the cooling fan. The induction heating cooker according to claim 1, which is arranged on the opposite side.