JP5855056B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker having a rice cooking amount determination function.

Conventionally, various rice cookers for determining the amount of rice and water introduced into the inner pot have been proposed in order to perform optimum heating amount input and rice cooking control according to the amount of rice cooked.
As a conventional example for discriminating the amount of cooked rice, for example, one that directly measures the total weight of rice and water using a weight sensor is disclosed (for example, see Patent Document 1).
Moreover, what determines the amount of rice cooking by measuring the time required for the temperature change of an inner pot to pass between two predetermined points with the temperature sensor provided in the inner pot vicinity (for example, patent document 2) is disclosed. reference).
Furthermore, what is disclosed is a method in which heating is performed for a predetermined period, and when the inner pot temperature reaches a preset temperature, the energization to the rice cooking heater is temporarily interrupted, and the amount of rice cooking is determined from the temperature drop at that time. (For example, refer to Patent Document 3).

Japanese Patent Laid-Open No. 5-261018 (for example, page 3, FIG. 4) JP-A 64-34309 (for example, page 4, FIG. 4 etc.) Japanese Patent Laid-Open No. 3-212215 (for example, pages 2, 3 and 4)

However, as in Patent Document 1, for example, the method of directly measuring the weight of the contents (rice and water) of the inner pot requires a weight sensor and a structural part that holds the weight sensor, so the structure is complicated, The rice cooker becomes larger.
Further, as in Patent Document 2, for example, the method of heating the inner pot, detecting the temperature rise of the inner pot with a temperature sensor, and determining the amount of cooked rice is used when the amount of the contents of the pot is small (for example, the amount of cooked rice 1 In other words, since the temperature of the pot suddenly rises, a response delay of the temperature sensor is added, and the temperature of the rice in the pot sometimes increases excessively. In this case, optimal temperature control cannot be performed in the subsequent rice cooking process, resulting in an unintended cooking result.

  Furthermore, since the temperature sensor measures the temperature only at a predetermined point on the bottom of the pot, temperature unevenness occurs in the pot due to the content bias or the like, and the amount of cooked rice cannot be estimated accurately. Providing a plurality of temperature sensors in preparation for such a case leads to an increase in cost and size.

  In addition, as in Patent Document 3, for example, the one that heats the pot for a predetermined time and then temporarily shuts off the power to the heater and determines the amount of rice cooking from the temperature drop at that time has a small heating amount at the time of heating. From a small amount of rice to a medium amount of rice, it can be detected, but the temperature difference (signal difference) between the two is small and the determination is difficult. When the amount of heating is increased in response to such a case, when the amount of rice in the inner pot is small, the temperature of the rice increases excessively, and appropriate rice cooking control cannot be performed in the subsequent rice cooking process.

  The present invention has been made to solve the above-described problems, and the rice cooking amount can be accurately determined with a simple configuration while suppressing the temperature of the rice to a temperature that does not affect the rice cooking step at the time of rice cooking amount determination. It aims at providing the rice cooker which can be determined.

The rice cooker according to the present invention includes a heating unit that heats the rice cooking container, a drive unit that supplies power to the heating unit, a first temperature detection unit that detects the temperature of the rice cooking container, and an inner side of the rice cooking container. 2nd temperature detection means which measures temperature, and the rice cooking amount determination means which determines the amount of rice cooking in the said rice cooking container, The said rice cooking amount determination means heats the said rice cooking container with the said heating means, Then, the said rice cooking The heating to the container is stopped, the first rice cooking amount determination for determining the amount of rice cooking in the rice cooking container is executed by the amount of change of the signal detected by the first temperature detection means, and the rice cooking container is heated by the heating means. And the 2nd rice cooking amount determination which determines the rice cooking amount in the said rice cooking container with the variation | change_quantity of the signal detected by the said 2nd temperature detection means is performed , and the rice cooking amount determined by the said 2nd rice cooking amount determination is said 1st. Cooking cooked by 1 cooked rice amount judgment It is those greater than the amount.

  According to the rice cooker of the present invention, since the determination of the amount of cooked rice is performed using two determination algorithms, the temperature rise of the rice can be suppressed even when the amount of cooked rice is determined, and the amount of cooked rice can be accurately determined. it can.

It is a schematic block diagram which shows roughly an example of a structure of the rice cooker which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the flow of the process in the case of the rice cooking amount determination operation | movement of the rice cooker which concerns on Embodiment 1 of this invention. It is a graph which shows an example of ideal rice cooking temperature transition. It is the graph which showed the detection signal transition of the 1st temperature detection means at the time of the rice cooking amount determination of the rice cooker which concerns on Embodiment 1 of this invention. It is the graph which showed transition of the detection signal of the 2nd temperature detection means at the time of rice cooking amount determination of the rice cooker which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the flow of the process in the case of the rice cooking amount determination operation | movement of the rice cooker which concerns on Embodiment 2 of this invention. It is a conceptual diagram which shows an example of the table which prescribed | regulated the input electric energy corresponding to the initial temperature of the rice cooker of the rice cooker which concerns on Embodiment 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Further, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common throughout the entire specification. Furthermore, the forms of the constituent elements shown in the entire specification are merely examples, and are not limited to these descriptions.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram schematically showing an example of a configuration of a rice cooker 100 according to Embodiment 1 of the present invention. Based on FIG. 1, the structure of the rice cooker 100 is demonstrated.

  This rice cooker 100 cooks a to-be-heated object by induction-heating the rice cooker 1 in which the to-be-heated object (foodstuffs, such as rice and water) was put by the heating coil 2. As shown in FIG. Specifically, as shown in FIG. 1, the rice cooker 100 detects the temperature of the rice cooker 1 in which an object to be heated is placed, the heating coil 2 that heats the rice cooker 1, and the temperature of the rice cooker 1. 1 temperature detection means 3, second temperature detection means 4 for detecting the ambient temperature inside the rice cooker 1, a drive unit 5 for supplying current to the heating coil 2, a display operation unit 6, a control unit 7, It has.

  As shown in FIG. 1, the heating coil 2 is provided at the bottom and the outer periphery of the rice cooker 1. The 1st temperature detection means 3 is provided in the bottom center part of the rice cooker 1 so that the rice cooker 1 may be contact | connected. The 2nd temperature detection means 4 is provided inside the rice cooker lid 8 which comprises some rice cookers 100, and measures the space temperature of the inside vicinity of the rice cooker 1. FIG. The first temperature detection means 3 and the second temperature detection means 4 may be constituted by a thermistor, for example. The rice cooker lid 8 is provided so as to be openable and closable so as to cover an opening formed in the upper part of the rice cooker 1.

  The drive unit 5 includes at least a rectifying unit 10 that converts an AC voltage applied from a commercial AC power supply 9 into a DC voltage, an inverter circuit 11 that supplies a high-frequency current to the heating coil 2, and the like. The pot 1 is induction heated. Although details of the inverter circuit 11 are not particularly illustrated, for example, a one-stone voltage resonance inverter constituted by a power switching element, a resonance capacitor or the like, a half-bridge inverter, or the like is used for the inverter circuit 11.

  The display operation unit 6 includes an operation unit that receives a rice cooking instruction and a rice cooking condition setting from the user, and a display unit that displays an operation state, a message to the user, and the like. The display operation unit 6 outputs a signal based on the setting from the user to the control unit 7 and displays a message or the like based on the output from the control unit 7. Here, the case where the display unit and the operation unit are collectively used as the display operation unit 6 is shown as an example, but the display unit and the operation unit may be provided separately.

  The control unit 7 includes a microcomputer and a control circuit, and drives and controls the inverter circuit 11 according to a predetermined control sequence based on a signal from the display operation unit 6.

  In addition, the control part 7 is corresponded to the "rice cooking amount determination means" of this invention. That is, in the rice cooker 100, signals output from the first temperature detection means 3 and the second temperature detection means 4 are input to the control unit 7 and subjected to arithmetic processing to determine the amount of rice cooking. It is assumed that the control unit 7 includes a timer / counter function for measuring time and an A / D converter that converts an analog voltage signal into a digital signal.

  The configuration of the rice cooker 100 has been described above. In addition, in FIG. 1, although the drive part 5, the display operation part 6, and the control part 7 are drawn on the exterior of the housing 12 which comprises the rice cooker 100 for convenience, actually the inside of the housing 12 or the rice cooker lid 8 is drawn. It shall be stored inside.

Next, the operation of the rice cooker 100 will be described.
FIG. 2 is a flowchart illustrating an example of a processing flow in the rice cooking amount determination operation of the rice cooker 100. FIG. 3 is a graph showing an example of an ideal rice cooking temperature transition. FIG. 4 is a graph showing the detection signal transition of the first temperature detection means when the amount of rice cooked by the rice cooker 100 is determined. Here, it is assumed that the detection signal increases as the pot temperature increases, and the detection signal decreases as the pot temperature decreases. Hereinafter, the rice cooking amount determination operation of the rice cooker 100 will be described with reference to FIGS.

  Before operating the rice cooker 100, the user first sets the rice cooker 1 containing a predetermined amount of rice and water in the rice cooker body. Then, the user closes the rice cooker lid 8, turns on the power, selects the rice cooking menu with the display operation unit 6, presses a rice cooking switch (not shown), and gives an operation instruction to the rice cooker 100. The rice cooker 100 starts cooking rice when the rice cooking switch is pressed by the user and an operation instruction is given. That is, when the user operates the display operation unit 6 to give an instruction to start cooking such as a rice cooking instruction, the control unit 7 shifts to a rice cooking amount determination operation.

  Here, an example will be described in which the amount of cooked rice is determined in three stages: a small amount (for example, 1 go), a medium amount (for example, 3 go), and a large amount (for example, 5 go). The rice cooking amount determination operation is roughly divided into two steps, and the determination methods are different. It is determined whether the amount of cooking rice is small in the first step operation (small amount determination algorithm), and whether the amount of cooking rice is medium amount or large amount in the second step operation Yes (medium / large quantity judgment algorithm). When the rice cooking amount determination operation is completed, rice cooking control corresponding to each rice cooking amount is applied, and power input suitable for each rice cooking amount is performed.

As shown in FIG. 3, when the amount of rice cooking is not detected with respect to the curve representing the ideal rice cooking temperature (line (A) shown in FIG. 3), the rice cooking amount is compared with the ideal temperature when the amount of rice cooking is small. The temperature changes to higher (line (B) shown in FIG. 3).
On the other hand, if the amount of rice cooking is not detected for the curve representing the ideal rice cooking temperature (line (A) shown in FIG. 3), the rice cooking temperature will be lower than the ideal temperature if the amount of rice cooking is large. (Line (C) shown in FIG. 3).
That is, if the amount of cooked rice is known in advance, heating power can be input in accordance with the amount of cooked rice, so that rice can be cooked at an ideal temperature regardless of the amount of cooked rice.

First, the “small amount determination algorithm” will be described.
In the rice cooker 100, the control part 7 operates the drive part 5 and heats the rice cooker 1 for a predetermined time (steps S1 and S2 in FIG. 2). At this time, when the amount of rice in the rice cooker 1 is small, the heating power and the heating period are programmed in the control unit 7 in advance so that the temperature of the inside rice does not affect the cooking time (for example, 60 ° C.) or less. Keep it. If the temperature is less than the temperature that does not affect the rice cooking performance in a small amount, there is no problem because the temperature of the rice does not rise more than in a small amount when the amount of rice cooking is medium or large.

  After a predetermined time has elapsed (step S2 in FIG. 2; Yes), the control unit 7 stops the drive unit 5 and stops the heating operation (step S3 in FIG. 2). While the heating operation is stopped, the heat of the rice cooker 1 stored by heating is transferred to the internal water and rice, so the temperature of the rice cooker 1 gradually decreases. At this time, when there is little rice cooking amount, the contact area of the rice cooking pot 1 and water is small, the upper part of the rice cooking pot 1 is occupied by the air layer with small heat conductivity, and the temperature drop of the rice cooking pot 1 is small. On the other hand, when there is much rice cooking amount, since the upper part of the rice cooking pot 1 is occupied with rice and water, the contact area of the rice cooking pot 1 and water is large, and the temperature drop of the rice cooking pot 1 is large.

  Therefore, when the amount of rice cooking is small, the inclination of the temperature change of the rice cooker 1 becomes gentle, and when the amount of rice cooking is large, the inclination of the temperature change of the rice cooking pot 1 becomes large. The graph shown in FIG. 4 shows the signal waveform of the first temperature detecting means 3 obtained from the experiment conducted by the inventor of the present invention. It was obtained when heating, and then energizing was stopped and the signal of the first temperature detecting means 3 was measured. Here, all the signals of the first temperature detecting means 3 at the time of the start of the temperature drop are displayed so as to make it easy to compare the inclinations.

  As shown in FIG. 4, it can be seen that only when the amount of cooked rice is small, the slope of the signal, that is, the gradient of temperature change, becomes gentler than that of medium and large amounts, and a difference appears. On the other hand, it can be seen that when the amount of cooked rice is medium and large, the slope of the signal, that is, the slope of the temperature change is substantially the same, and the difference is small. This is because the input power and the input time are set so that the rice temperature at the time of a small amount is not more than a temperature that does not affect the rice cooking process.

  Since the rice cooker 1 is induction-heated by the heating coil 2 installed at the bottom, the vicinity of the bottom is heated. The heat at the bottom of the rice cooker 1 is transferred to the top of the pot by heat conduction, but since the input power and time are limited, the heat transferred to the top of the pot is small, and the heat transferred from the pot to the water is low at the top of the pot. small. Therefore, the first temperature detecting means 3 is used in the case of mass cooking where rice and water are introduced up to the upper part of the rice cooking pot 1 and in the case of medium quantity cooking where rice and water are introduced up to an intermediate height of the rice cooking pot 1. The difference in the signal waveform is difficult.

  While the heating operation is stopped, the signal output from the first temperature detection means 3 is input to the control unit 7 and converted from an analog value to a digital value by an A / D converter inside the microcomputer. The control unit 7 counts the time at the same time, obtains the time change amount (ΔTa / Δt) of the signal output from the first temperature detection means 3 (step S4 in FIG. 2), and determines whether the amount of rice cooking is small. (Step S5 in FIG. 2). Here, ΔTa represents the signal change amount of the first temperature detecting means 3, and Δt represents the time width at this time.

That is, when ΔTa / Δt is smaller than a predetermined value set in advance by the program, the controller 7 determines that the amount of rice cooking is a small amount (step S5 in FIG. 2; small amount).
Moreover, when ΔTa / Δt is larger than a predetermined value set in advance by the program, the control unit 7 determines that the amount of cooked rice is not small (Step S5 in FIG. 2; medium amount / large amount).
Here, if it is judged that it is small amount rice cooking, it will transfer to a rice cooking process and rice cooking will be performed by control suitable for small amount rice cooking (step S6 of FIG. 2). When it is determined that it is not a small amount of rice cooking, the process proceeds to the rice cooking amount determination operation in the second step.

Next, the “medium / large quantity determination algorithm” will be described.
If it determines with the control part 7 not being a small amount rice cooking, it will input electric power again by the drive part 5, and will heat the rice cooking pot 1 (step S7 of FIG. 2). In the “medium / large quantity determination algorithm”, it is determined whether the amount of cooked rice is medium or large from the temperature change of the second temperature detection means 4 provided inside the rice cooker lid 8. As shown in FIG. 1, the 2nd temperature detection means 4 is arrange | positioned so that the air temperature (atmosphere temperature) inside the rice cooking pot 1 can be measured.

  The amount of cooked rice is determined according to the following principle. When the rice cooker 1 is heated, the rice cooker 1 and the rice and water inside are heated, and the atmospheric temperature inside the rice cooker 1 gradually rises. At this time, if the amount of rice and water charged in the rice cooker 1 is different, the rate of increase in the atmospheric temperature inside the rice cooker 1 is different due to the difference in heat capacity. That is, if the amount of rice and water inside the rice cooker 1 is small, the temperature of the rice and water rises quickly, so that the ambient temperature inside the rice cooker 1 rises quickly. Conversely, if the amount of rice and water inside the rice cooker 1 is large, the temperature rise of rice and water is slow, so the rise in the atmospheric temperature inside the rice cooker 1 is slow. The amount of cooked rice is determined from the difference in the rising speed of the atmospheric temperature inside the rice cooker 1.

  A signal output from the second temperature detecting means 4 is input to the control unit 7 and converted from an analog value to a digital value by an A / D converter of the microcomputer. The control unit 7 counts the time at the same time, obtains the time change amount (ΔTb / Δt) of the signal output from the second temperature detection means 4 (step S8 in FIG. 2), and determines whether the amount of rice cooking is medium or large. Determination is made (step S9 in FIG. 2). Here, ΔTb represents the signal change amount of the second temperature detecting means 4, and Δt represents the time width at this time.

That is, when ΔTb / Δt is larger than a predetermined value set in advance by the program, the control unit 7 determines that the amount of rice cooking is a medium amount (step S9 in FIG. 2; medium amount).
Further, when ΔTb / Δt is smaller than a predetermined value set in advance by the program, the control unit 7 determines that the amount of rice cooking is large (step S9 in FIG. 2; large amount).
Here, if it is determined that it is medium-sized rice cooking, the process shifts to a rice cooking control process suitable for medium-sized rice cooking (step S10 in FIG. 2). (Step S11 in FIG. 2). Thereby, in the rice cooker 100, rice cooking can be performed by the optimal control suitable for each rice cooking amount.

  FIG. 5 is a graph showing the transition of the detection signal of the second temperature detection means 4 when determining the amount of rice cooked by the rice cooker 100. This FIG. 5 has shown the signal waveform of the 2nd temperature detection means 4 obtained from the experiment which the inventor of this invention conducted, and when the rice cooking pot 1 was heated for a fixed time by making the amount of rice cooking medium and large quantity. It was obtained. Here, it is assumed that the detection signal increases as the pot temperature increases, and the detection signal decreases as the pot temperature decreases.

From FIG. 5, the detection signal of the 2nd temperature detection means 4 rises with the internal atmosphere temperature rise of the rice cooker 1, However, A temperature change is large with medium amount rice cooking, and the output signal change amount of the 2nd temperature detection means 4 is large. It can be seen (line (D) shown in FIG. 5). Moreover, it turns out that a temperature change is small in mass rice cooking, and the output signal change amount of the 2nd temperature detection means 4 is small (line (E) shown in FIG. 5).
In order to easily compare the inclinations, the output signal of the second temperature detecting means 4 at the time of power-on is displayed so as to coincide with a medium amount and a large amount.

  Thus, since there is a difference in the output signal of the second temperature detection means 4 between the medium amount and the large amount, the rice cooking amount determination can be performed using this. In the “medium / large quantity determination algorithm”, the amount of cooked rice is determined based on changes in the air temperature (atmosphere temperature) around the inside of the rice cooker 1. Thereby, the stable temperature change can be caught compared with the case where one arbitrary place of the rice cooker 1 is directly temperature-measured.

  When rice is added to the rice cooker 1, convection is less likely to occur inside the rice cooker 1 than when water is used alone. Is likely to occur. Therefore, when measuring the temperature of the rice cooking pot 1 only at one arbitrary point, there is a possibility that the amount of rice cooking is erroneously determined due to the temperature unevenness of the rice cooking pot 1. On the other hand, the rice cooker 100 does not directly measure the temperature of the rice cooker 1, but detects the ambient temperature inside the rice cooker 1 by the second temperature detection means 4, so There is an advantage that it is not easily affected.

  Moreover, although the structure of the rice cooker 100 uses the microcomputer which comprises the 1st temperature detection means 3 provided in the pot bottom, the 2nd temperature detection means 4 provided in the rice cooker cover 8, and the control part 7, these are used. Since these are parts pre-equipped in a general rice cooker that is currently distributed, by using these, it can be realized only by the correspondence of the microcomputer program without additional members. Thereby, rice cooker 100 can be provided as a small and inexpensive product.

  As mentioned above, in the rice cooker 100, the algorithm which determines small amount rice cooking, and the algorithm which determines medium amount and large amount rice cooking are provided individually. In the “small amount determination algorithm”, the rice cooker 1 is heated for a predetermined period, and after a predetermined time has elapsed, the heating operation is stopped. And the temperature fall of the rice cooker 1 is detected by the 1st temperature detection means 3, time variation | change_quantity ((DELTA) Ta / (DELTA) t) is calculated | required, and it is discriminate | determined from the variation | change_quantity whether it is a small amount rice cooking. If it is a small amount of rice, then the process proceeds to the rice cooking process, and if it is determined that it is not a small amount of rice, the process continues to the “medium / large amount determination algorithm”.

  In the “medium / large quantity determination algorithm”, the rice cooker 1 is heated again, the atmospheric temperature inside the cooking rice cooker 1 being heated is detected by the second temperature detection means 4, and the amount of time change (ΔTb / Δt) is obtained. It is determined whether the amount of cooking rice is medium or large from the amount of change. And it shifts to a rice cooking process after that, and rice cooking control suitable for each amount of rice cooking is implemented.

  Since the “small amount determination algorithm” determines only whether the amount is small, the amount of input power during heating is small, and even if the amount of cooked rice is small, the inside rice can be kept below the temperature at which the rice cooking process is not affected.

  On the other hand, if the amount of cooked rice is medium or large, it will be heated again with the medium / large amount judgment algorithm removed in the case of a small amount. It can be suppressed to a temperature that does not reach. In addition, in the “medium / large quantity determination algorithm”, the temperature of the rice cooker 1 is not directly measured, but the amount of rice cooked is determined from the atmosphere temperature inside the rice cooker 1, so that the influence of temperature unevenness of the rice cooker 1 is reduced. be able to. Therefore, according to the rice cooker 100, the amount of cooked rice can be determined more accurately.

  In addition, although demonstrated here in the example which determines the amount of rice cooking in three steps, a small amount, a medium amount, and a large amount, it does not limit the amount of rice cooking to three steps, The temperature of the rice cooking pot 1 by the 1st temperature detection means 3 is demonstrated. The amount of rice cooking may be further divided and determined from the amount of change and the amount of change in the ambient temperature inside the rice cooker 1 by the second temperature detection means 4. For example, when discriminating the amount of cooked rice into five levels, the first step (for example, 1 go) and the second step (for example, 2 go) are determined using the “small amount determination algorithm” from the side with the smaller amount of cooked rice, and 3 steps (for example, 3 go) ), 4 stages (for example, 4 go) and 5 stages (for example, 5 go) can also be determined using the “medium / large quantity determination algorithm”.

  In addition, during power-on to the rice cooker 1 in the “small amount determination algorithm” and “medium amount / large amount determination algorithm”, the drive unit 5 and the control unit 7 perform constant power feedback control so that the input power becomes constant. The influence of fluctuations in power supply voltage can be eliminated. Therefore, the determination accuracy of the amount of cooked rice can be improved, and erroneous determination can be prevented. In constant power feedback control, for example, the heating power to the rice cooker 1 may be directly measured, compared with the target power, and the drive unit 5 may be controlled by the control unit 7 so as to match the target power. In addition, for example, the power input current is measured by a current transformer, the heating power to the rice cooker 1 is indirectly detected from the power input current, and the drive unit 5 is controlled by the control unit 7 so that the power input current becomes the target current. You may control.

  Moreover, although the case where the induction heating by the heating coil 2 was utilized was demonstrated to the example as a means to heat the rice cooker 1, it is not limited to this, You may use the heating means by a heating wire, a sheathed heater, etc. .

Embodiment 2. FIG.
A rice cooker according to Embodiment 2 of the present invention (hereinafter, not shown, but referred to as rice cooker 110 for convenience) will be described. In the second embodiment, the difference from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted. In addition, since the structure of the rice cooker 110 which concerns on Embodiment 2 is the same structure as the rice cooker 100 of FIG. 1 shown in Embodiment 1 of this invention, description is abbreviate | omitted.

  As with the rice cooker 100 according to the first embodiment, the rice cooker 110 cooks the heated object by heating the cooker 1 containing the heated object (food such as rice and water) with the heating coil 2. To raise. The difference between the rice cooker 110 and the rice cooker 100 is that the first temperature detection means 3 detects the initial temperature of the rice cooker 1 before the “small amount determination algorithm”, and the “small amount determination algorithm” and the “medium amount / large amount determination algorithm”. "At the time of implementation, it is possible to adjust the input power amount when heating the rice cooker 1 according to the initial temperature of the rice cooker 1.

Next, the operation of the rice cooker 110 will be described.
FIG. 6 is a flowchart illustrating an example of a processing flow in the rice cooking amount determination operation of the rice cooker 110. FIG. 7 is a conceptual diagram showing an example of a table that defines the input power amount corresponding to the initial temperature of the rice cooker 1 of the rice cooker 110.

  When the display operation unit 6 is operated by the user and an instruction to start rice cooking such as a rice cooking instruction is made, the control unit 7 shifts to a rice cooking amount determination operation. Here, before implementing the “small amount determination algorithm”, the initial temperature of the rice cooker 1 is measured by the first temperature detection means 3 (step S0 in FIG. 6). After the initial temperature measurement of the rice cooker 1 is completed, the “small quantity determination algorithm” is executed next.

  In the “small amount determination algorithm”, the rice cooker 1 is heated for a predetermined time as in the first embodiment (step S1 in FIG. 6), but based on the initial temperature of the rice cooker 1, the heating power amount to the rice cooker 1 is calculated. adjust. For example, the control unit 7 has a table inside the microcomputer program as shown in FIG. 7, refers to the input power amount corresponding to the measured initial temperature of the rice cooker 1, and the drive unit 5 is based on that. The rice cooker 1 is heated. As the initial temperature of the rice cooker 1 is lower, the output signals of the first temperature detection means 3 and the second temperature detection means 4 are less likely to cause a difference in the amount of time change between the rice cooking amounts. The relationship between the amounts of electric power is a> b> c> d, and the lower the initial temperature of the rice cooker 1 is, the higher the input electric energy is (increased), and the higher the initial temperature of the rice cooker 1 is, the smaller the input electric energy is (lower) )

  After heating for a predetermined time, as in the first embodiment, the control unit 7 stops the driving unit 5 and stops the heating operation (step S3 in FIG. 6). A time change amount (ΔTa / Δt) of the signal output from the first temperature detection means 3 at this time is obtained (step S4 in FIG. 6), and it is determined whether or not it is a small amount of rice cooking (step S5 in FIG. 6). At this time, you may change suitably the time variation | change_quantity used as the determination threshold value which determines whether it is a small amount rice cooking according to the input electric energy at the time of the heating of the rice cooking pot 1. FIG. Here, if it is judged that it is small amount rice cooking, it will transfer to rice cooking control and rice cooking will be performed by the control suitable for small amount rice cooking (step S6 of FIG. 6). When it is determined that it is not a small amount of rice cooking, the rice cooking amount determination operation in the second step is continued.

  Next, the “medium / large quantity determination algorithm” will be described. As in the first embodiment, the control unit 7 turns on the power again (step S7 in FIG. 6) and determines the amount of rice cooked by the second temperature detection means 4, but also for the “medium / large amount determination algorithm” Based on the initial temperature of the rice cooker 1, the heating power amount to the rice cooker 1 is adjusted. For example, as in the “small amount determination algorithm”, the control unit 7 has a table in the microcomputer program as shown in FIG. 7 and refers to the input power amount corresponding to the measured initial temperature of the rice cooker 1. The drive part 5 heats the rice cooker 1 based on it. The input power amount is increased as the initial temperature of the rice cooker 1 is lower, and the input power amount is decreased as the initial temperature of the rice cooker 1 is higher.

  After a predetermined time has elapsed, the control unit 7 obtains a time change amount (ΔTb / Δt) of the signal from the signal output from the second temperature detection means 4 (step S8 in FIG. 6), and the amount of rice cooking is medium amount from this value. Or a large amount (step S9 in FIG. 6). That is, when ΔTb / Δt is larger than a predetermined value set in advance by the program, the control unit 7 determines that the amount of rice cooking is a medium amount, and ΔTb / Δt is a predetermined value set in advance by the program. If it is smaller than that, the amount of cooked rice is judged to be large.

  Here, if it is determined that the amount of rice is medium, the process shifts to a rice cooking control process suitable for medium-sized rice cooking (step S10 in FIG. 6). (Step S11 in FIG. 6). Thereby, in the rice cooker 110, rice cooking can be performed by the optimal control suitable for each rice cooking amount. Here, the amount of time change (ΔTb / Δt) serving as a determination threshold value for determining whether the rice is cooked in a medium amount or a large amount may be appropriately changed according to the amount of input power when the rice cooker 1 is heated.

  Thus, in Embodiment 2, in the rice cooking amount determination operation, the initial temperature of the rice cooking pot 1 is measured, and the rice cooking pot in the “small amount determination algorithm” and the “medium amount / large amount determination algorithm” according to this temperature. The heating power amount of 1 is adjusted. When the initial temperature of the rice cooker 1 is low, the input power amount is increased, and when the initial temperature of the rice cooker 1 is high, the input power amount is decreased. Thus, for example, even if the temperature of the rice cooker 1 varies depending on the season or the temperature of the water to be added to the rice cooker 1, the variation in the determination signal due to the difference in the initial temperature of the rice cooker 1 is corrected by adjusting the amount of input power. can do.

  Therefore, according to the rice cooker 110 which concerns on Embodiment 2, the stable rice cooking amount determination is attained, the determination accuracy of the rice cooking amount can be improved, and an erroneous determination can be prevented. Moreover, when initial temperature is high, since input electric energy is reduced, it can suppress to the temperature (for example, 60 degreeC) below the rice which the rice inside the rice cooking pot 1 does not affect a rice cooking process.

  The input power amount is represented by the product of the heating power of the rice cooker 1 and the heating time, and the adjustment of the input power amount is to adjust the heating time with the heating power fixed or with the heating time fixed. Or both of them may be adjusted. In the second embodiment, the input power amount is adjusted by both the “small amount determination algorithm” and the “medium amount / large amount determination algorithm”, but the “small amount determination algorithm” or the “medium amount / large amount determination algorithm”. It is also possible to adjust the input power amount of only one of them.

  As in the first embodiment, the amount of cooked rice is further determined from the amount of change in the temperature of the rice cooker 1 by the first temperature detection means 3 and the amount of change in the ambient temperature inside the rice cooker 1 by the second temperature detection means 4. You may judge by dividing finely. In addition, as in the first embodiment, during the power-on to the rice cooker 1 in the “small amount determination algorithm” and the “medium amount / large amount determination algorithm”, the input power is made constant by the drive unit 5 and the control unit 7. Alternatively, constant power feedback control may be performed. Further, as in the first embodiment, heating means such as a heating wire or a sheathed heater may be used.

  DESCRIPTION OF SYMBOLS 1 Rice cooker (rice cooker), 2 Heating coil, 3rd temperature detection means, 4nd temperature detection means, 5 Drive part, 6 Display operation part, 7 Control part, 8 Rice cooker lid, 9 Commercial AC power supply, 10 Rectification unit, 11 inverter circuit, 12 housing, 100 rice cooker, 110 rice cooker.

Claims (6)

Heating means for heating the rice cooking container;
A drive unit for supplying power to the heating means;
First temperature detecting means for detecting the temperature of the rice cooking container;
Second temperature detection means for measuring the temperature inside the rice cooking container;
A rice cooking amount determination means for determining the amount of rice cooking in the rice cooking container,
The rice cooking amount determination means is:
After heating the rice cooking container by the heating means, the heating to the rice cooking container is stopped, and the first rice cooking amount determination for determining the rice cooking amount in the rice cooking container by the change amount of the signal detected by the first temperature detection means. Run
The rice cooking container is heated by the heating means, and a second rice cooking amount determination is performed to determine the amount of rice cooking in the rice cooking container with the amount of change of the signal detected by the second temperature detection means,
The cooking amount determined by the second cooking amount determination 炊 rice instrument you characterized by more than judges cooking amount by the first cooking amount determination. The rice cooking amount determination means is:
The rice cooker according to claim 1, wherein after the first rice cooking amount determination is performed, the second cooking rice amount determination is performed again by heating the rice cooking container with the heating unit. Before performing the first rice cooking amount determination, the first temperature detection means detects the temperature of the rice cooking container as an initial temperature,
The rice cooker according to claim 1 or 2 , wherein the amount of electric power for heating the rice cooking container in the first rice cooking amount determination is decreased as the initial temperature of the rice cooking container is higher. Before performing the first rice cooking amount determination, the first temperature detection means detects the temperature of the rice cooking container as an initial temperature,
The amount of power for heating the cooking vessel in the second cooking amount determination, rice cooker according to any one of claims 1 to 3, wherein the reducing higher initial temperature is higher of the cooking container. In the first rice cooking amount determination and the second rice cooking amount determination,
The constant-power feedback control which carries out constant control of the heating electric power of the said rice cooking container to predetermined electric power is performed. The rice cooker as described in any one of Claims 1-4 characterized by the above-mentioned. A rice cooker lid that covers the opening of the rice cooker so as to be freely opened and closed,
The second temperature detecting means includes
It is provided in the said rice cooker lid. The rice cooker as described in any one of Claims 1-5 characterized by the above-mentioned.

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