JPH09108097A - Electric cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric cooker which can insulate heat with tastiness kept as intact by preventing dry hardening or charring of cooked rice within a pot even when a foreign matter happens to be thrown between a pot bottom sensor for detecting the temperature of the bottom surface or side of the pot and the bottom of the pot. SOLUTION: A lid body 19 is provided with a lid temperature sensor 25 and a pot is heated when the detection temperature by a pot bottom temperature sensor 8 is below a set temperature and that by a lid temperature sensor below a lid set temperature. When the detection temperature by the pot bottom temperature sensor is above a bottom set temperature or that by the lid temperature sensor above a lid set temperature, a heating value is reduced thereby preventing the cooked rice within the pot from drying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety measure for keeping an electric cooker such as an electric rice cooker warm.

[0002]

2. Description of the Related Art Conventionally, an electric rice cooker with a heat retaining function is based on the output of a pot temperature detecting means (pot bottom sensor) that abuts the pot bottom as seen in Japanese Patent Publication No. 6-98081.
The heating means (heater) for heating the pan and the lid was controlled to keep the rice at a constant temperature.

[0003]

However, if foreign matter such as rice is caught between the pan bottom and the pan bottom sensor, the pan bottom and pan bottom sensor will not be in close contact with each other, and the temperature of the pan will be transmitted to the temperature sensor. It gets harder.

If heat retention control is carried out normally in such a state, the temperature of the pan is originally the upper limit of the proper heat retention temperature, and although it is necessary to stop the heat generation of the heating means, As described above, since the bottom of the pan and the bottom sensor of the pan are not in close contact with each other, the bottom sensor of the pan cannot accurately detect the upper limit of the proper temperature for keeping the bottom of the pan, and the bottom of the pan is judged not to reach the upper limit temperature yet. However, there was a defect that the temperature of the rice in the pan rises and it dries and becomes hard, and in some cases it burns.

Therefore, according to the present invention, the rice in the pan is dried and hardened even if foreign matter is caught between the pan temperature detecting means (pan bottom sensor) for detecting the temperature of the bottom or side of the pan and the pan bottom. In some cases, it is possible to prevent burning and provide an electric rice cooker that can keep warm in a delicious state.

[0006]

According to the present invention, there is provided a cooker main body, a pan for accommodating an object to be cooked which is detachably attached to the cooker main body, and first heating means for heating the pan. First temperature detecting means for detecting the temperature of the bottom or side of the pot,
The second temperature detecting means provided in the lid body for covering the pot of the cooker body, the second heating means for heating the pot surface side of the lid body, and the output of the first temperature detecting means are set to the first setting. When the output of the second temperature detecting means is equal to or lower than the temperature and is equal to or lower than the second set temperature, the food to be cooked is heated by the first and second heating means, and the output of the first temperature detecting means is equal to the second temperature. When the temperature is equal to or higher than one set temperature or the second temperature detection unit is equal to or higher than the second set temperature, the heating amounts of the first and second heating units are reduced.

The second set temperature is set higher than the first set temperature.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a sectional view of the electric rice cooker. (1) is a cooker main body, which is a frame (2) made of synthetic resin, an outer frame (3) made of metal, a bottom plate (4) made of synthetic resin provided below the outer frame, and the outer frame (3). And a pan (5) made of a magnetic material (iron or stainless steel) that can be stored inside the bottom plate (4).

Reference numeral (6) is an induction coil (hereinafter referred to as a coil) which is a first heating means and which is in close contact with the lower surface of the bottom plate (4),
(7) is a side heater mounted on the outer wall of the outer frame (3), and (8) is a pan bottom serving as a first temperature detecting means for penetrating the central portion of the bottom plate (4) and bringing its upper surface into close contact with the pan bottom. Temperature sensor, (9) is a coil base for supporting the coil (6), (10) is ferrite for shielding provided on the lower surface of the coil base, (11) is a bottom wall of the frame (2) and ferrite A choke coil (13) and a heat dissipation plate (14) are attached to a power supply board arranged in a space (12) below (10). (15) is a fan for cooling the radiator plate, (16) is a control board arranged in a space (17) between the side wall of the frame (2) and the outer frame (3), and (18) is a frame for the frame (2). It is a frame cover for fixing the upper portion of each of the outer frames (3).

Reference numeral (19) is a lid body having one side pivotally supported on the cooker body (1) and the other side engageable with the cooker body, and includes an upper plate (20), a lower plate (21) and a metal. The heat dissipation plate (22) and the inner lid (23) provided below the heat dissipation plate. (24) is a lid heater which is mounted on the upper surface of the heat dissipation plate (22) and serves as a second heating means for heating the pot surface side of the lid body,
Reference numeral (25) is a lid temperature sensor which is provided in the lid and is arranged between the lower plate (21) and the heat radiating plate (22) and serves as a second temperature detecting means. (26) is an outer packing fitted and fixed to the outer peripheral edge of the heat sink (22), (27) is an inner packing fitted and fixed to the outer peripheral edge of the inner lid (23), (2)
8) is a steam hole that opens the upper plate (20) and the heat radiating plate (22) to communicate with the outside air, and (29) is a pressure adjusting device provided in the central portion of the inner lid (23), and a plurality of pressure adjusting devices are provided in the lower portion. A hollow valve casing (31) having a plurality of pressure relief holes (30), a valve seat (33) having a pressure hole (32) provided in the lower portion of the valve casing, and a valve seat (33) mounted on the valve seat and always placed. The pressure regulating valve (34) for closing the pressure hole (32).

FIG. 3 is a block diagram of the electric rice cooker of the present invention. (M) is a control means including a microcomputer programmed with a predetermined series of rice cooking operations and a warming operation after completion of rice cooking, a pan bottom temperature detecting means (TM) including a pan bottom temperature sensor (8), and a lid temperature sensor. -By inputting the upper lid temperature detecting means (TF) including (25), the pan bottom heating means (HM) including the coil (6) and the side heating means (HS) including the side heater (7) according to a pre-programmed procedure. And an upper lid heating means (H
F).

The electric power of each heating means is designed by the maximum heating amount required for rice cooking. The maximum electric power of each heating means is 50 W for the lid heater (24) and 30 W for the side heater (7).
The coil (6) is heated at 1200W. Further, the coil (6) can be changed almost continuously from 350 W to 1200 W by changing the control frequency of induction heating. Further, the control of the average power described later is performed by changing the energization duty of these heaters,
In the present invention, by changing the ratio of energization and non-energization during 16 seconds, for example, 6.3 W of the lid heater (24)
Is realized by energizing a 50 W heater for 2 seconds in 16 seconds, and 28.4 W of the induction coil (6) by heating 350 W for 1.3 seconds in 16 seconds.

Next, the operation of the pan bottom temperature sensor (8) when there is no foreign matter in the normal state is shown in FIG.
This will be described with reference to the flowchart of.

FIG. 4 shows a state in which the rice is cooked (after the rice is cooked), the water content in the pan evaporates, and the rice reaches about 100 ° C. and is being lowered to around 70 ° C. by heat retention control. Pan bottom threshold (ki) that reaches the first set temperature
In the normal state without the pan bottom temperature sensor (8), the rice in the pan is set to exhibit 72.5 degrees. In the present invention, the pan bottom threshold is set to 68.3 degrees. There is.

The upper lid threshold value (K), which is the second set temperature, is a feature of the present invention. When the pot bottom temperature sensor (8) is in a normal state where there is no foreign matter, and the lid temperature is kept at a predetermined power balance. The temperature that the sensor (25) can exhibit is set to a temperature with a slight margin, and in the present invention, it is set to a value obtained by adding 10 degrees from the pan bottom threshold value. In the graph (m) is the pan bottom sensor from the pan bottom temperature detection means (TM).
The temperature, (m) indicates the temperature of the upper lid sensor detected by the upper lid temperature detecting means (TF), and (m) indicates the average temperature of the rice in the pan. The pan bottom sensor-temperature (m) is influenced by the pan bottom heating means (HM) and changes so as to pulse according to the control state.

The upper lid temperature is also the same, and the upper lid heating means (HF) is used.
It is changing so as to be pulsed under the influence of. The fact that the temperature of the rice in the pan exhibits a higher value than the pan bottom temperature is also a feature of the induction heating system of the embodiment of the present invention, in which the energy of the induction heating coil that is the pan bottom heating means first heats the pan, This is because the energy is transferred to the rice in the pot and the pot bottom temperature detecting means.

The temperature detected by the upper lid temperature detecting means is higher than the temperature of the rice in the pan because the moisture of the rice does not condense on the inner lid (23) and so-called dew does not adhere to the upper lid heating means. This is because the heating balance is set to be high.

The control mode before point (a) until the temperature of the rice is lowered and the temperature of the pan bottom sensor reaches the pan bottom temperature threshold (ki) is the cooling mode (S1), and each heating means for heating the pan. The average electric power of the heater is 6.3 W for the top lid heater, 7.5 W for the side heater, and 0.0 W for the pot bottom heater (S2). Also, from the start of this heater control, the timer ( CM) starts timing. (S3).

As described above, this heating balance is achieved by the inner lid (2
In order to prevent dew from adhering to 3), it is a set value peculiar to the main body of this embodiment so that the temperature of the upper lid is slightly higher than the temperature of the rice in the pan. Further, each electric power is shown as an average electric power, and the heating method is as described above. At this time,
According to the determination of the cooling mode on the flowchart (S4),
Until the temperature of the pan bottom sensor-temperature (m) reaches the pan bottom threshold (ki), the top heater is 6.3 W, the side heater is 7.5 W, and the pan bottom heater is 0.0 W as described above. S
5) When the time measured by the timer (CM) reaches 16 seconds set in advance, the process proceeds to Yes (S6), and then the pot bottom sensor-temperature and the pot bottom threshold value are compared. At this point, the pot bottom temperature is normally set. Since the temperature of the sensor is high, the process proceeds to No (S7).

When the temperature of the rice further decreases and reaches the point (a) in the graph of FIG. 4, step (S) of the flow chart.
In 7), the temperature of the pan bottom temperature sensor-becomes lower than the threshold value of the pan bottom, and the process proceeds to Yes. Further, when the temperature of the lid sensor is lower than the threshold value of the lid, the process proceeds to Yes in the normal state (S8), and the control is performed. The mode is set to the heating mode and the timer (CM) is reset (S9). The timer (CM) at this time is reset to stabilize the control, and the heating mode does not return to the cooling mode for 16 seconds.

In the heating mode, the average electric power of each heating means for heating the pot is 17.5 W for the upper lid heater and 2 for the side heater as shown in the region from point (a) to point (a) in the graph of FIG.
6.3W, pan bottom heater is 28.4W (S1
0).

When the temperature rises and the pan bottom sensor reaches the pan bottom threshold (g) again and reaches point (a), a timer
When the time measured by (CM) reaches 16 seconds, the process proceeds to Yes (S11).

After that, when the temperature of the pan bottom sensor is lower than the threshold value of the pan bottom and the temperature of the upper lid temperature sensor is lower than the threshold value of the upper lid (S12) (S13), the heater control is terminated (S14).

If the pan bottom sensor-temperature is higher than the pan bottom threshold value at the position of step (S12) or the top lid temperature sensor-temperature is higher than the top lid threshold value at the position of step (S13). The control mode is set to the cooling mode and the timer (CM) is reset (S1)
5).

Similarly, after the graph (c) point, the same operation as described above is repeated.

The electric power in the cooling mode and the electric power in the heating mode are the electric power values specific to the present embodiment, which are determined so that the heating cycle and the cooling cycle are repeated within the range where the ambient temperature during use is considered.

Further, the steps on the flowchart (S1
1) and (S6) are provided so that the cooling mode and the heating mode do not reciprocate in a short time in order to stabilize the control.

Next, according to the present invention, a pan bottom temperature sensor- (8)
The operation when foreign matter such as rice grains adheres to the upper surface of is described with reference to the graph of FIG. 5 and the flowchart of FIG.

Up to the point (a) in the graph, since there is no energization by the pan bottom heating means, the temperature value detected by the pan bottom temperature detecting means operates almost in the same manner as in normal times without being significantly affected by foreign matter. . When the pan bottom detection temperature exceeds point (a), the pan mode is switched to the heating mode, and when the pan bottom heating means is energized,
The amount of heat received by the pan bottom sensor becomes smaller than the amount of heat received by the rice in the pan, and the temperature difference gradually begins to appear. The temperature of the upper lid sensor also starts to rise because the heating amount is higher than usual. Eventually, when the temperature difference between the pan bottom sensor temperature and the actual pan bottom temperature becomes stable, and the natural cooling amount from the pan is balanced, the temperature of the rice in the pan reaches a constant temperature. However, the temperature is much higher than in the normal state, and depending on the conditions, it rises from the latter half of the 70 degrees to the worst of 90 degrees, and becomes abnormally dry or scorched.

When the temperature of the rice reaches the point (D), in the step (S13) on the flowchart in the heating mode, the process shifts from No to Yes and shifts to the cooling mode. In the mode, the branch dominated by the step (S7) on the flow chart is controlled by the step (S8). In terms of the movement on the graph, the control by the pan bottom sensor and the pan bottom threshold is The temperature is controlled by the upper lid sensor and the upper lid threshold. At this point, the temperature rise of the rice in the pan stops, and although it shows a higher temperature than usual, it is suppressed to around 75 degrees, and it is possible to suppress abnormal drying and burning as described above.

In this embodiment, an induction heating type rice cooker has been described as an example, but it can be applied to a heating type rice cooker other than induction heating.

[0032]

As described above, according to the present invention, the bottom temperature detecting means cannot accurately capture the temperature of the bottom of the pan due to foreign matter, and even if the temperature of the contents of the pan rises, the temperature of the top lid temperature detecting means causes the rice in the pan to cook. By detecting and controlling the temperature, it is possible to suppress the abnormal temperature rise of the rice in the pan and keep it warm without abnormal drying or burning.

[Brief description of the drawings]

FIG. 1 is a flowchart of a heat retaining operation in an electric cooker according to the present invention.

FIG. 2 is a structural sectional view of the same.

FIG. 3 is a block diagram similarly.

FIG. 4 is a heat retention characteristic diagram of a normal state.

FIG. 5 is a heat retention characteristic diagram similarly when an abnormality occurs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooker main body 5 Pan 6 Induction coil (first heating means) 8 Pan bottom temperature sensor- (first temperature detection means) 19 Lid body 24 Lid heater (second heating means) 25 Lid temperature sensor- (second temperature detection means) ) M control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuo Tanigawa 3 201 Minamiyoshikata Minamiyoshikata, Tottori City, Tottori Prefecture Tottori Sanyo Electric Co., Ltd. (72) Yuji Saito 3201 201 Minamiyoshikata Minamiyoshikata, Tottori City Tottori Sanyo Within the corporation

Claims (2)

[Claims] 1. A cooker main body, a pan for accommodating an object to be cooked which is detachably attached to the cooker main body, a first heating means for heating the pan, and a temperature of a bottom surface or a side surface of the pan. A first temperature detecting means for detecting, a second temperature detecting means provided in a lid for covering the pot of the cooker body, a second heating means for heating the pot surface side of the lid, When the output of the one temperature detecting means is below the first set temperature and the output of the second temperature detecting means is below the second set temperature, the food to be cooked is heated by the first and second heating means, and When the output of the first temperature detecting means is equal to or higher than the first preset temperature or the second temperature detecting means is equal to or higher than the second preset temperature, the heating amount of the first and second heating means is decreased. Electric cooker 2. The electric cooker according to claim 1, wherein the second preset temperature is set higher than the first preset temperature.