JP7547548B2 - Cooking equipment - Google Patents

Description

The present invention relates to a cooking device that heats food while stirring it.

Conventionally, cooking devices that heat and stir ingredients or other objects are known. For example, Patent Document 1 discloses a rice cooker that has a stirrer that is rotated by a rotor disposed between the main body and the lid.

In a cooking device with such an agitator, when a signal instructing stirring is given at regular intervals, the rotor rotates the agitator in a certain direction.

JP 2013-188292 A

In a cooking device like the one described above, if the amount of food being stirred increases, the load on the motor driving the stirring arm increases when the stirring arm is in contact with the food, and the stirring arm may not be able to rotate. This is because the power applied to achieve the target amount of rotation differs depending on the amount of food being stirred. Therefore, in such a case, it is necessary to increase the power (torque) of the motor in order to rotate the stirring arm.

The present invention was made in consideration of the above problems, and its purpose is to suppress an increase in the power of the motor that drives the mixing arm even if the amount of heated material to be mixed increases.

In order to solve the above problem, a cooking device according to one aspect of the present invention includes a stirring body that stirs an object to be heated, a motor that rotates the stirring body, and a motor control unit that controls the rotation of the motor so that the stirring body rotates and stops in the normal rotation direction multiple times, and the motor control unit controls the rotation of the motor so that the stirring body rotates in the opposite direction to the normal rotation direction by an amount smaller than the amount of rotation in the normal rotation direction after or before the stirring body finishes rotating in the normal rotation direction.

According to one aspect of the present invention, it is possible to suppress an increase in the power of the motor that drives the mixing arm even if the amount of heated material to be mixed increases.

1 is a perspective view showing a state in which a lid of a rice cooker according to a first embodiment of the present invention is closed. FIG. FIG. 2 is a perspective view showing the rice cooker with the lid open. 2 is a perspective view showing a mixing state of a first mixing arm and a second mixing arm in the rice cooker. FIG. FIG. 2 is a vertical cross-sectional view showing the internal structure of the rice cooker. FIG. 2 is a block diagram showing the configuration of a control system of the rice cooker. FIG. 2 is a block diagram showing the configuration of a motor control system of the rice cooker. 5 is a waveform diagram showing a concept of motor rotation control by a motor control unit in the motor control system. FIG. 10 is a graph showing a comparison of changes in motor power with respect to the number of stirring times between the stirring method of the rice cooker described above and a conventional stirring method. FIG. 11 is a block diagram showing the configuration of a motor control system of the rice cooker according to the second embodiment. 10 is a flowchart showing a procedure for motor power control by the motor control system of FIG. 9 . 10 is a graph showing a comparison of changes in motor power with respect to the number of stirring times between a stirring method using a rice cooker having the motor control system of FIG. 9 and a conventional stirring method. 10 is a waveform diagram showing a specific example of motor rotation control by a motor control unit in the motor control system of FIG. 9 . 10 is a flowchart showing a procedure for controlling the actual number of rotations of the motor by the motor control system of FIG. 9 . FIG. 11 is a block diagram showing the configuration of a heating control system according to a third embodiment of the rice cooker.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG.

Figure 1 is a perspective view showing the rice cooker 100 (heat cooking device) according to embodiment 1 with the lid 2 closed. Figure 2 is a perspective view showing the rice cooker 100 with the lid open. Figure 3 is a perspective view showing the stirring state of the first stirring arm 12A and the second stirring arm 12B in the rice cooker 100. Figure 4 is a vertical cross-sectional view showing the internal structure of the rice cooker 100. The structure of the rice cooker 100 will be described with reference to these figures.

As shown in FIG. 1, the rice cooker 100 comprises a rice cooker body 1 and a lid body 2 attached to the top of the rice cooker body 1. The rice cooker 100 is configured so that it can be used not only for cooking rice, but also for cooking stews, steamed dishes, etc.

The front of the rice cooker body 1 is provided with an open button 3 for opening the lid 2. Meanwhile, a plug at the end of a power cord 4 protrudes from the rear of the rice cooker body 1. Most of this power cord 4 is wound around a cord reel (not shown) inside the rice cooker body 1 so that it can be pulled out.

At the front of the top surface of the lid 2, there is a liquid crystal display 5 that displays the cooking method and cooking name, and an operation section 6 consisting of multiple operation switches. In addition, steam from the inner pot 7 shown in Figure 2 is discharged from a steam exhaust port 2a at the rear of the top surface of the lid 2.

As shown in FIG. 2, the rice cooker body 1 contains an inner pot 7, which is opened and closed by a lid 2.

A latching portion 8 is provided at the front of the top surface of the rice cooker body 1. A latching portion 23 provided at the front of the bottom surface of the lid body 2 latches releasably to the latching portion 8. When the open button 3 is pressed, the latching portion 8 moves rearward, and the latching of the latching portion 23 to the latching portion 8 is released.

An induction coil 10 is installed in the rice cooker body 1 to inductively heat the inner pot 7. The induction coil 10 is an example of a heating unit.

The inner pot 7 contains rice, water, and the like as examples of contents. The inner pot 7 is made of a highly heat-conductive material such as aluminum. A magnetic material such as stainless steel is attached to the outer surface of the inner pot 7 to improve heating efficiency. Meanwhile, the inner surface of the inner pot 7 is coated with a fluororesin to prevent the contents from sticking to it.

The lid body 2 has an outer lid 21 that is located on the opposite side to the inner pot 7 when the lid body 2 is closed, and an inner lid 22 that is located on the inner pot 7 side when the lid body 2 is closed. A motor 24 is disposed in the right corner of the rear of the outer lid 21. A connecting shaft (not shown) is rotatably disposed in the inner lid 22. This connecting shaft rotates by receiving the rotational driving force generated by the motor 24 via a pulley and belt (not shown).

A stirring unit 50 is rotatably attached to the lid 2. This stirring unit 50 rotates by the driving force of the motor 24 to stir the contents contained in the inner pot 7.

As shown in Figures 2 and 3, the agitation unit 50 has a rotating body 11 and a first agitation arm 12A and a second agitation arm 12B as agitation bodies.

The rotating body 11 is rotatably attached to the lid body 2. The first stirring arm 12A and the second stirring arm 12B are swingably attached to the rotating body 11 and are arranged to sandwich the rotating body 11.

The first agitating arm 12A and the second agitating arm 12B are rotatably attached to the rotor 11 so that they can be switched between a non-agitating state (see FIG. 2) in which they are arranged along the side of the rotor 11, and an agitating state (see FIG. 3) in which they extend vertically from the non-agitating state. In the agitating state, the first agitating arm 12A and the second agitating arm 12B extend toward the inner pot 7 as shown in FIG. 3, so that they come into contact with the rice and other ingredients in the inner pot 7.

As shown in FIG. 4, a lid heater 13 for heating the inner lid 22 is provided on the upper surface of the inner lid 22. A heat retention heater 14 for keeping the heated object in the inner pot 7 warm is provided on the outer surface of the inner pot 7. Furthermore, the above-mentioned induction coil 10 is disposed directly below the bottom of the inner pot 7. A temperature sensor 15 for detecting the temperature of the inner pot 7 is disposed in the space on the inner periphery of the induction coil 10. The temperature sensor 15 is a sensor for detecting the temperature of the inner pot 7, and is composed of, for example, a thermistor. The temperature sensor 15 is disposed so as to be in contact with the bottom of the inner pot 7.

Next, the control system of the rice cooker 100 will be described. FIG. 5 is a block diagram showing the configuration of the control system of the rice cooker 100. FIG. 6 is a block diagram showing the configuration of the motor control system of the rice cooker 100.

As shown in FIG. 5, the rice cooker 100 includes, as the main components of its control system, a CPU (Central Processing Unit) 16, a ROM (Read Only Memory) 17, and a RAM (Random Access Memory) 18. The rice cooker 100 also includes a motor drive circuit 19 that drives the motor 24, and an FG sensor 20 that detects the rotation of the motor 24.

The CPU 16 controls each part by executing a control program stored in the ROM 17. Specifically, the CPU 16 controls the display of the display unit 5, accepts operations on the operation unit 6, controls the on/off and temperature of the induction coil 10, the lid heater 13, and the warming heater, and controls the drive of the motor drive circuit 19.

An FG sensor 20 is attached to the motor 24. For example, the motor 24 is a DC motor. The outer periphery of the rotor has 360 FG (Frequency Generator) teeth that are magnetized so that N and S poles are arranged alternately. The FG sensor 20 is a magnetic sensor such as a Hall element or MR sensor that detects the magnetic field generated by the rotation of the rotor, and outputs a pulsed FG signal.

The CPU 16 measures the period (FG value) of the FG signal and outputs a PWM signal to achieve the target FG value. The CPU 16 also outputs an on/off signal that turns the motor 24 on and off, and a rotation direction signal that specifies the direction of rotation of the motor 24.

The motor drive circuit 19 rectifies the PWM signal to generate a DC voltage to be applied to the motor 24. The motor drive circuit 19 also drives and stops the motor 24 based on the on/off signal. Furthermore, the motor drive circuit 19 rotates the motor 24 in the forward direction or reverse direction based on the rotation direction signal.

As shown in FIG. 6, the rice cooker 100 has a motor control unit 25. The motor control unit 25 is a part that realizes the motor control function of the CPU 16, and outputs the above-mentioned PWM signal, on/off signal, and rotation direction signal. The motor control unit 25 also has a normal rotation control unit 26 and an irregular rotation control unit 27. The normal rotation control unit 26 operates in a normal stirring mode, and the irregular rotation control unit 27 operates in an irregular stirring mode.

The normal stirring mode is applied when the load on the first stirring arm 12A and the second stirring arm 12B is small, for example, when the weight of the heated object is smaller than a predetermined value, or when a cooking menu with a light load such as boiled noodles is selected. The irregular stirring mode is applied when the load on the first stirring arm 12A and the second stirring arm 12B is large, for example, when the weight of the heated object is equal to or larger than a predetermined value, or when the amount of the heated object is increased in a cooking menu such as simmered food. The load can also be measured by the current value flowing through the motor 24. The weight of the heated object can be measured, for example, by installing a weight sensor (not shown) at the bottom of the inner pot 7.

The normal rotation control unit 26 and the irregular rotation control unit 27 operate by appropriately determining whether the normal stirring mode or the irregular stirring mode is applied depending on the instruction input to the operation unit 6 (such as a cooking menu designation or an instruction to increase the amount of food to be heated). In both the normal stirring mode and the irregular stirring mode, it is predetermined that the first stirring arm 12A and the second stirring arm 12B rotate a predetermined number of times within a predetermined time, with a predetermined rotation amount for each rotation, depending on the cooking menu.

The normal rotation control unit 26 rotates the motor 24 in the forward direction so as to rotate the first agitation arm 12A and the second agitation arm 12B a specified number of times in the agitation direction (normal rotation direction).

The irregular rotation control unit 27, like the normal rotation control unit 26, rotates the motor 24 in the forward direction so that the first agitation arm 12A and the second agitation arm 12B rotate in the agitation direction a specified number of times. In addition to the basic rotation control described above, the irregular rotation control unit 27 also rotates the motor 24 in the reverse direction after and before the end of rotation in the normal rotation direction so that the first agitation arm 12A and the second agitation arm 12B rotate slightly in the direction opposite to the normal rotation direction after and before the end of rotation in the normal rotation direction for each rotation.

The operation of the rice cooker 100 configured as described above in the normal stirring mode and the irregular stirring mode will be described. Figure 7 is a waveform diagram showing the concept of the rotation control of the motor 24 by the motor control unit 25 in the motor control system. Figure 8 is a graph showing the change in the power of the motor 24 with respect to the number of stirring cycles, comparing the stirring method of the rice cooker 100 with a conventional stirring method.

In the normal stirring mode, the normal rotation control unit 26 operates to output a PWM signal, an on/off signal, and a forward rotation direction signal. The motor drive circuit 19 rotates the motor 24 according to the time, number of rotations, and amount of rotation specified based on these signals.

In normal stirring mode, the load on the first stirring arm 12A and the second stirring arm 12B is small. Therefore, even if the first stirring arm 12A and the second stirring arm 12B rotate only in the forward direction from the state where they are in contact with the heated object, the load on the motor 24 is small, so the first stirring arm 12A and the second stirring arm 12B can be rotated according to the target.

In the irregular stirring mode, the irregular rotation control unit 27 operates to output a PWM signal, an on/off signal, and a rotation direction signal for reverse rotation/forward rotation. The motor drive circuit 19 rotates the motor 24 according to the time, number of rotations, and amount of rotation specified based on these signals. As shown in FIG. 7, the motor 24 rotates in reverse after rotating in the forward direction (forward rotation) for each rotation. Alternatively, the motor 24 rotates in reverse before rotating forward for each rotation, as shown by the dashed line in FIG. 7.

As a result, the first agitator arm 12A and the second agitator arm 12B rotate slightly in the reverse direction from the state where they are contacting the object to be heated after or before each normal rotation. Therefore, when they start to rotate in the forward direction, the first agitator arm 12A and the second agitator arm 12B are not contacting the object to be heated, so the load on the motor 24 is reduced. Then, the first agitator arm 12A and the second agitator arm 12B rotate slightly in the forward direction before contacting the object to be heated. Therefore, even if the amount of the object to be heated increases and the load on the motor 24 increases, the first agitator arm 12A and the second agitator arm 12B can be rotated according to the target without increasing the power of the motor 24.

Here, we will explain the change in power versus the number of stirring times when the first stirring arm 12A and the second stirring arm 12B are used to stir the heated object 10 times, comparing the stirring method according to this embodiment with the conventional stirring method (rotating only in the normal direction). The following is an example in which the ingredients for nikujaga (boiled meat and potatoes) for six people, a relatively large amount, are used as the heated object, and the target amount of stirring (target amount of rotation) per time is fixed at a constant value.

In the stirring method of this embodiment, as shown by the solid line in Figure 8, the target rotation amount is reached after the fourth stirring and the power of the motor 24 becomes almost constant. For the first four stirrings, the power of the motor 24 needs to be gradually increased so that the target stirring amount is reached. In addition, for the fifth stirring and after, the effect of rotating the motor 24 in the reverse direction after (or before) rotating forward appears, and the increase in the power of the motor 24 can be suppressed.

In contrast, in the conventional stirring method, as shown by the dashed line in FIG. 8, the power of the motor 24 is increased for the first four stirrings, as in the stirring method of this embodiment. However, the power of the motor 24 is also increased for the subsequent nine stirrings, until the target rotation amount is finally reached by the ninth stirring, and the power of the motor 24 becomes constant. The reason why the power of the motor 24 is increased up to the ninth stirring is that, for each stirring, the first stirring arm 12A and the second stirring arm 12B rotate in the stirring direction from the state where they are in contact with the heated object, placing a large load on the motor 24.

By adopting the stirring method of this embodiment, as shown in Figure 8, the power of the motor 24 required to reach the target rotation amount can be significantly reduced by a power difference ΔP compared to conventional stirring methods.

The amount of rotation (rotation angle) of the motor 24 during reverse rotation may be a predetermined ratio to the amount of rotation during forward rotation, or may be a fixed amount of rotation.

In addition, in this embodiment, two agitating arms, a first agitating arm 12A and a second agitating arm 12B, are used as the agitating body, but one or three or more agitating arms may be used.

In addition, in this embodiment, the normal stirring mode and the irregular stirring mode are selectively used, but the irregular stirring mode may be fixedly used as the normal stirring operation mode.

In addition, in this embodiment, the rice cooker 100 has been described, but the above-described rotation control of the first stirring arm 12A and the second stirring arm 12B can also be applied to a cooking device that does not have a rice cooking function. The embodiments 2 and 3 described below can also be applied to such cooking devices that do not have a rice cooking function.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to Figures 9 to 13. For ease of explanation, components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

Figure 9 is a block diagram showing the configuration of a motor control system for embodiment 2 of the rice cooker 100.

The rice cooker 100 according to this embodiment has a motor control unit 31 shown in FIG. 9 instead of the motor control unit 25 described above. The motor control unit 31 is a part that realizes the motor control function of the CPU 16 (see FIG. 5), and outputs the above-mentioned PWM signal, on/off signal, and rotation direction signal. The motor control unit 31 also has a rotation amount comparison unit 32 (rotation amount determination unit) and a power change unit 33.

The rotation amount comparison unit 32 compares the target rotation amount and the actual rotation amount of the motor 24 by comparing the target FG value FGt, which is determined based on the cooking menu, etc., with the actual FG value FGm, which the motor control unit 31 measures based on the FG signal from the FG sensor 20. The rotation amount comparison unit 32 also outputs a power change instruction signal that instructs a change in power when the difference between the target FG value FGt and the actual FG value FGm is equal to or greater than a predetermined value. The rotation amount comparison unit 32 also outputs a normal power instruction signal that sets the power to normal power when the difference between the target FG value FGt and the actual FG value FGm is less than a predetermined value.

When the power change unit 33 receives a power change instruction signal from the rotation amount comparison unit 32, it changes the power of the motor 24 from the next rotation to a predetermined value (predetermined PWM value) corresponding to the difference between the target FG value FGt and the measured FG value FGm. Also, when it receives a normal power instruction signal from the rotation amount comparison unit 32, it sets the power of the motor 24 to normal power from the next rotation. Note that when the power change unit 33 receives a power change instruction signal, it changes the rotation time of the motor 24 from the next rotation to a predetermined value corresponding to the power change instruction signal, and when it receives a normal power instruction signal, it sets the rotation time of the motor 24 to the normal power time from the next rotation. Also, when the power change unit 33 receives a power change instruction signal, it may change the current value flowing through the motor 24 to a predetermined value corresponding to the power change instruction signal while keeping the rotation time of the motor 24 the same from the next rotation (PAM control).

The operation of changing the power of the motor 24 by the motor control unit 31 configured as described above will be described with reference to FIG. 10. FIG. 10 is a flowchart showing the procedure for controlling the power of the motor 24 by the motor control system.

As shown in FIG. 10, first, the rotation amount comparison unit 32 compares the target FG value FGt with the measured FG value FGm (step S1). The rotation amount comparison unit 32 determines through the comparison whether the difference between the two is less than the first predetermined value D1, is equal to or greater than the first predetermined value D1 and less than the second predetermined value D2, or is equal to or greater than the second predetermined value D2 (step S2). Here, the second predetermined value D2 is a value greater than the first predetermined value D1.

When the rotation amount comparison unit 32 determines that the difference between the two is equal to or greater than the first predetermined value D1 and less than the second predetermined value D2, the power change unit 33 outputs a PWM signal to the motor drive circuit 19 to change the power in the next rotation from the current value by a small amount (first change amount). The motor 24 is driven by the motor drive circuit 19 based on the PWM signal, and rotates with the changed power by the small amount in the next rotation (step S3). For example, if the actual FG value FGm is smaller than the target FG value FGt by a value equal to or greater than the first predetermined value D1 and less than the second predetermined value D2, the motor 24 increases the power. Conversely, if the actual FG value FGm is larger than the target FG value FGt by the above value, the motor 24 reduces the power.

In step S2, if the rotation amount comparison unit 32 determines that the difference between the two is equal to or greater than the second predetermined value D2, the power change unit 33 outputs a PWM signal to the motor drive circuit 19 to change the power in the next rotation from the current value by a larger amount (second change amount). Here, the second change amount is a value greater than the first change amount. In step 3, the motor 24 is driven by the motor drive circuit 19 based on the PWM signal, and rotates at the changed power by the larger amount in the next rotation (step S4).

In step S2, if the rotation amount comparison unit 32 determines that the difference between the two is less than the first predetermined value D1, the power change unit 33 outputs a PWM signal to the motor drive circuit 19 so that the power of the motor 24 in the next rotation will be normal power. The motor 24 is driven by the motor drive circuit 19 based on the PWM signal, and rotates at normal power in the next rotation (step S5).

After step S3, step S4, or step S5, the rotation amount comparison unit 32 determines whether the specified number of rotations has been completed (step S6). If the rotation amount comparison unit 32 determines that the specified number of rotations has been completed (YES), it ends the process, whereas if it determines that the specified number of rotations has not been completed (NO), it performs the process of step S1 again.

In this way, when the difference between the actual rotation amount and the target rotation amount per stirring of the first stirring arm 12A and the second stirring arm 12B (motor 24) is equal to or greater than a predetermined value (first predetermined value), the motor control unit 31 changes the amount of change in power and time by which the actual rotation amount approaches the target rotation amount in the next rotation according to the magnitude of the difference. Specifically, the motor control unit 31 controls the motor 24 so that when the actual rotation amount is far from the target rotation amount, the amount of change is large, and when the actual rotation amount approaches the target rotation amount, the amount of change is small (returned to normal).

As a result, even if the weight of the object to be heated increases, the first agitating arm 12A and the second agitating arm 12B start to rotate earlier, and once the target rotation amount is reached, it is possible to maintain the target rotation amount without any significant deviation. Therefore, even if the weight range of the object to be heated increases, the first agitating arm 12A and the second agitating arm 12B can be rotated with power and time appropriate for each amount, so that the target rotation amount can be reached and maintained in a short time, as shown in FIG. 11.

Figure 11 is a graph showing the change in motor 24 power versus number of stirring cycles, comparing the stirring method used by rice cooker 100 with a conventional stirring method. Figure 11 shows an example in which ingredients for meat and potatoes (enough for six people) are used as the heated object, which is a relatively large amount. The conventional stirring method is an example in which the power is changed by a fixed value regardless of the difference between the actual rotation amount and the target rotation amount.

As shown in FIG. 11, in the stirring method of this embodiment, the target power is reached at time T1, as shown by the solid line. In contrast, in the conventional stirring method, the target power is finally reached at time T2, which is significantly longer than time T1, as shown by the dashed line. In this way, with the stirring method of this embodiment, the time to reach the target rotation amount can be significantly reduced compared to the conventional agitation method.

Here, a specific example of control of the motor 24 by the motor control unit 31 in accordance with the difference between the target rotation amount and the actual rotation amount will be described. FIG. 12 is a waveform diagram showing a specific example of rotation control of the motor 24 by the motor control unit 31 in the above motor control system. FIG. 12 shows an example in which the power of the motor 24 is changed in accordance with the difference between the actual rotation amount and the target rotation amount, without changing the rotation time of the motor 24. This example is not limiting, and the rotation time may be changed in accordance with the difference between the actual rotation amount and the target rotation amount, without changing the power of the motor 24.

As shown in FIG. 12, when the actual rotation amount is less than the target rotation amount, the motor control unit 31 increases the power of the motor 24 in the next rotation in accordance with the difference between the target rotation amount and the actual rotation amount. On the other hand, when the actual rotation amount is more than the target rotation amount, the motor control unit 31 attenuates the power of the motor 24 in the next rotation in accordance with the difference between the target rotation amount and the actual rotation amount. In this way, the motor control unit 31 controls the power of the motor 24 so that the actual rotation amount approaches the target rotation amount. Furthermore, when the actual rotation amount is equal to the target rotation amount, the motor control unit 31 maintains the power of the motor 24 in the next rotation.

For example, as cooking progresses, the object to be heated may become softer, or the object to be heated, such as jam, may become harder as it thickens and its viscosity increases. When the object to be heated becomes softer, the load on the motor 24 becomes lighter and it becomes easier to rotate, so the actual rotation amount becomes greater than the target rotation amount. In this case, the power of the motor 24 is controlled to decrease during the next rotation. On the other hand, when the object to be heated becomes harder, the load on the motor 24 becomes heavier and it becomes harder to rotate, so the actual rotation amount becomes less than the target rotation amount. In this case, the power of the motor 24 is controlled to increase during the next rotation.

The process shown in FIG. 10 ends when the rotation amount comparison unit 32 determines in step S6 that the motor 24 has completed a specified number of rotations in the program process, regardless of whether the motor 24 has actually rotated. However, even if the first agitation arm 12A and the second agitation arm 12B attempt to rotate the same number of times within a specified time, the number of times they actually rotate at the target rotation amount differs depending on the load (weight of the heated object). For this reason, when the load is small, over-mixing occurs, and conversely, when the load is large, undermixing occurs.

Furthermore, when there is a large amount of heated material (heavy material), even if the power for the next rotation is increased to reach the target rotation amount as quickly as possible, it takes several rotations to reach the target rotation amount, resulting in a difference in the actual number of rotations (mixing) compared to when there is a small amount of heated material (light material). For example, when rotating the first mixing arm 12A and the second mixing arm 12B 30 times in a heating time of 5 minutes, if there is a large amount of heated material, the motor control unit 31 controls them to rotate as quickly as possible using the above-mentioned process. However, if the first mixing arm 12A and the second mixing arm 12B cannot rotate according to the target rotation amount in the first few rotations, they will not be able to rotate correctly 30 times.

To eliminate such inconveniences, the motor control unit 31 further includes a rotation count unit 34 (rotation count unit) and a rotation count comparison unit 35.

When the rotation counting unit 34 determines that the target FG value FGt and the actual FG value FGm match, it determines that the motor 24 has rotated normally once, and adds 1 to the counted rotation count Nc (count value) to count the number of times the motor 24 has rotated normally.

The rotation count comparison unit 35 compares the count rotation count Nc with the specified rotation count Nt, which is predefined according to the cooking menu, etc. Furthermore, when the two match, the rotation count comparison unit 35 outputs an OFF signal to the power change unit 33 to stop the motor 24. Furthermore, when the two do not match, the rotation count comparison unit 35 outputs an ON signal to the power change unit 33 to rotate the motor 24 the next time.

The operation of the motor control unit 31 configured as described above to control the actual number of rotations of the motor 24 will be described with reference to FIG. 13. FIG. 13 is a flowchart showing the procedure for controlling the actual number of rotations of the motor 24 by the motor control unit 31.

As shown in FIG. 13, first, the rotation count count unit 34 sets the count rotation count Nc to 0 (step S11). Next, the rotation amount comparison unit 32 compares the target FG value FGt with the measured FG value FGm (step S12) and determines whether the two match (step S13). If the rotation amount comparison unit 32 determines that the two match (YES), the rotation count count unit 34 adds 1 to the count rotation count Nc (step S14).

Then, the rotation count comparison unit 35 compares the specified rotation count Nt with the counted rotation count Nc (step S15) and determines whether they match (step S16). If the rotation count comparison unit 35 determines that they match (YES), it determines that the motor 24 has rotated the target amount of rotations each time and completed the specified number of rotations Nt. This causes the power change unit 33 to stop the rotation of the motor 24 (step S17), and the mixing operation ends. Thereafter, the process moves to the next cooking stage as necessary.

If the rotation amount comparison unit 32 determines in step S13 that the target FG value FGt and the measured FG value FGm do not match, the process proceeds to step S15.

If the rotation count comparison unit 35 determines in step S16 that the two do not match, the process proceeds to step S12, and in the next rotation, the rotation amount comparison unit 32 compares the target FG value FGt with the measured FG value FGm.

In this way, the motor control unit 31 judges whether the actual rotation amount for each rotation of the motor 24 reaches the target rotation amount. Furthermore, the motor control unit 31 regards a rotation in which the actual rotation amount reaches the target rotation amount as a normal rotation, and controls the motor 24 to maintain the rotation operation until the normal rotation number reaches the specified number of rotations Nt. This makes it possible to unify the number of normal rotations as targeted to the specified number of rotations Nt, rather than the number of rotations attempted. Therefore, even for heated objects of different amounts, the total amount of stirring can be adjusted to the same extent without causing differences in the degree of stirring.

In addition, in step S13 described above, the rotation amount comparison unit 32 determines whether the target FG value FGt and the measured FG value FGm match or not, but it may also determine whether the measured FG value FGm reaches a predetermined percentage (e.g., 70%) of the target FG value FGt. This type of determination can be applied in cases where it is acceptable that one stirring cycle was completed as targeted, even if the target FG value FGt and the measured FG value FGm do not match, as long as the measured FG value FGm is reasonably close to the target FG value FGt.

In addition, the rotation amount comparison unit 32, power change unit 33, rotation number count unit 34, and rotation number comparison unit 35 of the motor control unit 31 may be incorporated as functions of the irregular rotation control unit 27 of the motor control unit 25 in embodiment 1.

[Embodiment 3]
Further, another embodiment of the present invention will be described below with reference to Fig. 14. For convenience of explanation, components having the same functions as those described in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

Figure 14 is a block diagram showing the configuration of a heating control system for embodiment 3 of the rice cooker 100.

As shown in FIG. 14, the rice cooker 100 according to this embodiment has a heating control unit 41. The heating control unit 41 is a part that realizes the heating control function of the CPU 16 (see FIG. 5), and controls the on/off and temperature of the warming heater 14 and the induction coil 10 based on the temperature of the inner pot 7 detected by the temperature sensor 15. For this reason, the heating control unit 41 has a temperature rise measurement unit 42 and a temperature rise determination unit 43.

The temperature rise measurement unit 42 measures the temperature rise ΔT of the inner pot 7 from the start of heating for a specified time based on the temperature detected by the temperature sensor 15.

When the temperature rise determination unit 43 determines that the amount of heated object is small when the temperature rise ΔT is equal to or greater than a predetermined temperature, it controls the heater 14 to be turned off during heat retention.

This prevents the heated food from boiling over or overheating, and prevents the food from burning or sticking to the sides of the inner pot 7. It also contributes to saving electricity by eliminating unnecessary power consumption. When the temperature rise determination unit 43 determines that the amount of heated food is small during warming, it turns off the warming heater 14 located on the side of the inner pot 7 and turns on the induction coil 10 located on the bottom of the inner pot 7 to keep the food warm.

In this embodiment, a configuration has been described in which a warming heater 14 is provided on the side surface of the inner pot 7, and an induction coil 10 is provided on the bottom surface of the inner pot 7. In contrast, the heating means may be configured to provide heaters on both the side surface and bottom surface of the inner pot 7, or to provide induction coils on both the side surface and bottom surface of the inner pot 7.

[Software implementation example]
The control blocks of the rice cooker 100 (particularly the motor control unit 31 and the heating control unit 41) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software using the CPU 16.

In the latter case, the rice cooker 100 includes a CPU 16 that executes the commands of a program, which is software that realizes each function, a ROM 17 or storage device (these are referred to as "recording media") in which the program and various data are recorded so as to be readable by a computer (or CPU), and a RAM 18 in which the program is expanded. The object of the present invention is achieved when the computer (or CPU 16) reads (loads) the program from the recording media and executes it. The recording media may be "non-transient tangible media," such as tapes, disks, cards, semiconductor memories, and programmable logic circuits. The program may also be supplied to the computer via any transmission medium (such as a communication network or broadcast waves) capable of transmitting the program. The present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

〔summary〕
The heating cooker of aspect 1 of the present invention comprises a stirring body (first stirring arm 12A and second stirring arm 12B) for stirring the heated material, a motor 24 for rotating the stirring body, and a motor control unit 25, 31 for controlling the rotation of the motor 24 so that the stirring body rotates multiple times in the normal rotation direction, and the motor control unit 25, 31 controls the rotation of the motor so that the stirring body rotates in a rotation direction opposite to the normal rotation direction after or before the end of rotation in the normal rotation direction for each rotation.

According to the above configuration, the stirring body rotates slightly in the reverse direction from the state where it was in contact with the object to be heated when the previous rotation ended, and then rotates in the normal rotation direction. As a result, at the start of each rotation in the normal direction, the stirring body is away from the object to be heated, so the load on the motor is reduced. And, by rotating slightly in the normal rotation direction before the stirring body hits the object to be heated, the motor power can be reduced compared to rotating in the normal rotation direction from the beginning of the rotation.

In the cooking device according to aspect 2 of the present invention, in the above aspect 1, when the difference between the target rotation amount and the actual rotation amount of the motor 24 is equal to or greater than a predetermined value, the motor control unit 31 may change the power of the motor in the next rotation by an amount corresponding to the difference.

According to the above configuration, when the difference between the actual rotation amount of the motor and the target rotation amount is large, the amount of change in motor power can be increased in the next rotation so that the target rotation amount is approached more quickly. This makes it possible to reach the target power in a shorter time even when the amount of heated material is large.

In the cooking device according to aspect 3 of the present invention, in the above aspect 1 or 2, the motor control unit 31 may further include a rotation amount determination unit that determines whether the actual rotation amount in one rotation of the motor reaches the target rotation amount, and a rotation number counting unit that counts the number of rotations that the motor has rotated normally when the actual rotation amount reaches the target rotation amount, and may maintain the rotation operation of the motor until the count value of the rotation number counting unit reaches a specified number of rotations Nt.

With the above configuration, the number of times the target rotation amount is normally rotated, rather than the number of rotation attempts, can be unified to the specified number of rotations Nt. Therefore, even if the amount of heated material is different, the total amount of stirring can be adjusted to the same level without causing differences in the degree of stirring.

The cooking device according to each aspect of the present invention may be realized by a computer. In this case, the control program for the cooking device, which causes the computer to operate as each unit (software element) of the cooking device to realize the cooking device, and the computer-readable recording medium on which the control program is recorded, also fall within the scope of the present invention.

[Additional Notes]
A heating cooker according to another aspect of the present invention comprises a stirring body for stirring an object to be heated, a motor for rotating the stirring body, and a motor control unit for controlling the rotation of the motor so that the stirring body rotates multiple times in a normal rotation direction, and the motor control unit controls the rotation of the motor so that, during each rotation, the stirring body rotates in a direction opposite to the normal rotation direction by an amount smaller than the amount by which it rotates in the normal rotation direction after or before rotation in the normal rotation direction ends.

The cooking device according to another aspect of the present invention is further characterized in that, when the difference between the target rotation amount and the actual rotation amount of the motor is equal to or greater than a predetermined value, the motor control unit changes the power of the motor in the next rotation by an amount corresponding to the difference.

In another aspect of the cooking device of the present invention, the motor control unit further includes a rotation amount determination unit that determines whether the actual rotation amount in one rotation of the motor reaches the target rotation amount, and a rotation number counting unit that counts the number of rotations that the motor has rotated normally when the actual rotation amount reaches the target rotation amount, and is characterized in that the rotation operation of the motor is maintained until the count value of the rotation number counting unit reaches a specified number of rotations.

A control program according to another aspect of the present invention is a control program for causing a computer to function as the heating cooker according to the above-mentioned another aspect, and is a control program for causing a computer to function as the motor control unit.

A recording medium according to another aspect of the present invention is a computer-readable recording medium having recorded thereon a control program according to the above-mentioned another aspect.

In another embodiment of the cooking device of the present invention, the amount of rotation smaller than the normal rotation direction is an amount by which the stirring body moves away from the heated object that is in contact with the stirring body when the stirring body is stopped and no longer comes into contact with the heated object.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

12A First stirring arm (stirring body)
12B Second stirring arm (stirring body)
24 Motor 25, 31 Motor control unit 27 Irregular rotation control unit 32 Rotation amount comparison unit (rotation amount determination unit)
33 Power changing section 34 Rotation number counting section (rotation number counting section)
35 Rotation number comparison unit 100 Rice cooker (heating cooking device)
Nc Number of counted rotations (count value)
Nt Specified number of revolutions

Claims (3)

A stirring body that stirs the object to be heated;
A motor that rotates the stirring body;
a motor control unit that controls the rotation of the motor so that the stirring body rotates in a normal rotation direction and stops multiple times;
The motor control unit controls the rotation of the motor so that the stirring body rotates in a direction opposite to the normal rotation direction an amount smaller than the amount of rotation in the normal rotation direction after rotation in the normal rotation direction has ended or before rotation begins. The cooking device according to claim 1, characterized in that the stirring body is provided separately from the pot that contains the object to be heated. The cooking device according to claim 1 or 2, characterized in that, during cooking of stewed food, the motor control unit controls the rotation of the motor so that the stirring body rotates in a direction opposite to the normal rotation direction by an amount smaller than the amount of rotation in the normal rotation direction after rotation in the normal rotation direction has ended or before rotation starts.

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