JP2531803B2 - Jar rice cooker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a jar rice cooker, and more particularly, to smoothing the temperature of a heated object during a spotty period immediately after the heated object such as rice is cooked. The present invention relates to a jar rice cooker capable of appropriately heating the article to be heated by controlling the temperature of the jar.

[Prior art]

FIG. 4 is a time chart showing an example of heating control by a conventional jar rice cooker.

When an object to be heated such as rice is set and heating is started (a), the object to be heated is heated and its temperature rises ((a) to (b)) and reaches a predetermined temperature (for example, 110 ° C) ( B) The intermittent energization control of the power supply is performed to throttle the power supply. After that, when the temperature of the object to be heated rises to a temperature (for example, 125 ° C.) (C), intermittent energization control is performed ((C)).
~ (J)).

Conventionally, a heat source for heating control during the uneven period has been a heater.

[Problems to be Solved by the Invention]

4 (c) to 4 (h) show an example of the temperature change of the object to be heated during the purging period by the above-mentioned conventional heating control method. The temperature changes abruptly within the temperature range ΔT, and a smooth temperature change suitable for unevenness is not obtained.

It is possible to perform fine control such as making the on / off frequency of the heater finer in order to gently change the temperature, but the heat capacity of the heater itself and the heat of the heater are transferred to the object to be heated. It was not easy to design so as to smoothly change the temperature of the object to be heated by the synergistic effects of the heat capacity of inclusions and the capacity of the kettle for each model.

Therefore, the evaporation of water from the heated object such as rice may be insufficient, or the heated object may be burnt too much.

In addition, rapid heating is performed after a certain period of time (c) after cooking ((d), (f)). As a conventional technique for resting the heating for a predetermined time after such cooking, there is one disclosed in JP-A-63-139517. In this case, since the cooked rice is cooled rapidly once, there is a drawback in that the purging process becomes insufficient.

Therefore, the present invention has been made for the purpose of providing a jar rice cooker capable of appropriately controlling the temperature of an object to be heated during the uneven period without cooling once, and capable of appropriately heating the object to be heated. It is a thing.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a jar rice cooker that heats an object to be heated by supplying a heating power for heating the object to be heated by electromagnetic induction, and immediately after the object to be heated is cooked. The control means for gradually controlling the heating power is provided.

[Action]

In this jar rice cooker, since heating power for heating the object to be heated is supplied by electromagnetic induction, the object to be heated is directly heated without the heat capacity of inclusions or the like.

Therefore, during the unevenness period after the object to be heated is cooked, the temperature of the object to be heated can be adjusted according to the heating power without once cooling the temperature of the object to be heated by gradually reducing the heating power immediately after cooking. It is easy to change smoothly.

Therefore, it is possible to heat the object to be heated appropriately without causing insufficient evaporation of water in the object to be heated such as rice or overburning the object to be heated.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. It should be noted that the following embodiments are examples of embodying the present invention and are not of the nature to limit the technical scope of the present invention.

FIG. 1 is a control circuit diagram of a jar rice cooker according to an embodiment of the present invention, FIG. 2 (a) is a time chart showing an example of heating control of an object to be heated by the jar rice cooker, and FIG. 2 (b). )
Is an enlarged time chart showing a part of the time chart in an enlarged manner, and FIG. 3 is a time chart showing another example of heating control of the object to be heated by the jar rice cooker of FIG.

The control circuit 1 of the jar rice cooker shown in FIG. 1 is mainly composed of a control unit 2 including a microcomputer CPU and the like, and a display unit 3 for displaying the operating state of the jar rice cooker on the control unit 2. An input / output unit 4 for giving various input commands, an A / D conversion circuit 7 for converting an analog signal from a thermistor 6 that comes into contact with the inner pot 5 and detects the temperature of a heated object in the inner pot 5 into a digital signal A drive pulse generation circuit for controlling the drive circuit 9 for driving the high frequency switching element 8
An analog switch 11 for supplying a control signal to 10 is connected.

Further, the drive pulse generating circuit 10 includes a heating coil 15
Of the thermistor 6, a triangular wave generating circuit 17 for generating a triangular wave by a signal from a timing circuit 16 for generating a timing signal based on the voltage across both ends, and an overvoltage detecting circuit 18 for detecting an overvoltage of the voltage applied to the heating coil 15. A disconnection detection circuit 19 for detecting a disconnection abnormality is connected.

The high-frequency switching element 8 turns on / off the current of the power source which is rectified by the rectifier circuit 12, smoothed by the choke coil 13 and the capacitor 14, and supplied to the heating coil 15.

As a result, an alternating magnetic field is generated by the heating coil 15,
The inner pot 5 is heated by electromagnetic induction based on the alternating magnetic field,
An object to be heated, such as rice, set in the inner pot 5 in advance is heated.

Therefore, in this jar rice cooker, the object to be heated such as rice is directly heated by the inner pot 5 which is heated by the electromagnetic induction, and there is no heat capacity of the heater or inclusions. There is no delay, and it is easy to smoothly control the temperature of the object to be heated by reducing the heating power in the uneven period as described later.

In this jar rice cooker, a heating control signal is applied from the control unit 2 to the analog switch 11 based on the temperature detection signal of the object to be heated by the thermistor 6, and high frequency switching is performed via the drive pulse generation circuit 10 and the drive circuit 9. The element 8 is on / off controlled to control heating power for heating an object to be heated.

Next, an example of heating control of the object to be heated by the jar rice cooker will be described with reference to FIGS. 2 (a) and 2 (b).

When an object to be heated such as rice is set and heating is started (A), the object to be heated is heated by the maximum power of 1300 W and its temperature rises ((A) to (A)), and a predetermined temperature (for example, 11
(B), the heating power is controlled to 1000W.

After that, the temperature of the object to be heated rises (for example, 12
When the temperature reaches 5 ° C. (C), the heating power is controlled immediately after that (M) to (D) as shown in the figure.
As a result, the water can be sufficiently evaporated without once cooling the object to be heated.

FIG. 2 (b) shows the uneven period ((c) to FIG. 2 (a)).
It is a time chart which expands and shows the state of heating electric power control of (D).

As shown in this figure, in this uneven period, the maximum output of heating power is reduced to 500 W, and as this output is turned on and off, and the "unevenness" progresses, this off period gradually becomes longer and the heating The power is gradually reduced.

Since the object to be heated is directly heated by the gradually reduced heating power as described above, the temperature of the object to be heated during this uneven period is as shown by x ₁ in FIG. 2 (a). , Changes smoothly according to the heating power.

Therefore, the evaporation of the moisture of the heated object becomes insufficient,
Or do not overburn the object to be heated,
It is easy to appropriately heat the object to be heated in an arbitrary manner.

FIG. 3 shows another example of the heating power control in the above-mentioned unevenness period, in which the on / off intervals of the heating power in the unevenness period ((C) to (D)) are constant and "Murashi" The maximum output is gradually reduced from 700W to 200W as the progresses, and the heating power is gradually reduced. In this case as well, the evenness control is performed immediately after cooking to prevent the object to be heated from cooling.

Also in this example, as shown in FIG. 3 x ₂ , the temperature of the object to be heated during this uneven period changes smoothly according to this heating power, so that the object to be heated is moderately heated. .

〔The invention's effect〕

In a jar rice cooker for heating the object to be heated according to the present invention, heating power for heating the object to be heated is supplied by electromagnetic induction, and the heating power is gradually increased immediately after the object to be heated is cooked. A jar rice cooker characterized by being squeezed is provided.

Therefore, it is possible to easily change the temperature of the object to be heated smoothly according to the heating power without suddenly decreasing the temperature of the object to be heated. It is possible to heat the object to be heated moderately without becoming insufficient or not burning the object to be heated too much.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of a jar rice cooker according to an embodiment of the present invention, FIG. 2 (a) is a time chart showing an example of heating control of an object to be heated by the jar rice cooker, and FIG. 2 (b). ) Is an enlarged time chart showing a part of the same time chart, FIG. 3 is a time chart showing another example of heating control of the object to be heated by the jar rice cooker of FIG. 1, and FIG. It is a time chart which shows an example of heating control by a jar rice cooker. [Description of symbols] 1 ... Control circuit, 2 ... Control unit 5 ... Inner pot, 6 ... Thermistor 7 ... A / D conversion circuit 8 ... High-frequency switching element 9 ... Drive circuit 10 ... Drive pulse Generation circuit 11 …… Analog switch 15 …… Heating coil 16 …… Timing circuit 17 …… Triangle wave generation circuit

Claims (1)

(57) [Claims] 1. A jar rice cooker for heating an object to be heated, supplying heating power for heating the object to be heated by electromagnetic induction, and gradually heating the heating power immediately after the object to be heated is cooked. A jar rice cooker characterized by being squeezed into