JP2011245119A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker capable of automatically controlling the rice washing according to the amount of rice washed, controlling the amount of rice bran remaining in the rice after the washing, suppressing the outflow of nutrients provided in the rice while removing the smell of the rice bran, and performing rice-washing operation for bringing out the full flavor of the rice.SOLUTION: In this rice cooker 100, before a heating unit 3 performs heating, a control unit 31 detects the amount of rice in an inner bowl 2 by driving a stirring motor 4, thereby rotating a stirring blade 5, and using a motor current detection unit 36 to detect the amount of current flowing through the stirring motor 4. In accordance with the detected amount of rice, the control unit 31 controls the speed at which to have the stirring motor 4 rotationally drive the stirring blade 5 during rice-washing operation. This makes it possible to adjust the speed of the stirring blade 5 during rice-washing operation to fit the amount of rice.

Description

  The present invention relates to a rice cooker, and more particularly, to a rice cooker having a function of scrubbing rice grains to wash rice.

  Washing polished rice before cooking rice is widely recognized as common sense, but since washing rice before cooking is cumbersome, techniques for automating this have been developed. In the technique disclosed in Patent Document 1 (Japanese Utility Model Publication No. 62-182132), a stirring blade driven by an electric motor is attached to a lid body that is attached to the inner pot of a rice cooker, and the stirring blade is rotated to rotate the rice. Is washing.

  Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2-213121), the method of washing rice by rotating the rice cooker itself is devised. Moreover, in patent document 3 (Unexamined-Japanese-Patent No. 4-38918), the rice cooker provided with the temperature sensor for the temperature measurement at the time of rice cooking is also proposed, and automatic rice washing is possible by rotating a rice cooker. Yes. Patent Document 4 (JP-A-4-240421) proposes a technique capable of accurately measuring the weight of rice and water directly with a rice cooker while being a rice cooker capable of automatically washing rice. Further, Patent Document 5 (Japanese Patent Laid-Open No. 4-158818) proposes an automatic rice washing control method that enables appropriate rice washing with an appropriate amount of water.

  In the prior art described above, in the technique disclosed in Patent Document 1, it is possible to automate the washing of rice with a stirring blade. However, for example, when it is desired to leave a little rice cake, it is difficult to control the washing of rice.

  Moreover, in the technique disclosed in Patent Document 2, the rice cooker itself is rotated to wash the rice, so there is a possibility that the whole rice does not move. Moreover, the temperature sensor described in patent document 3 and the weight sensor described in patent document 4 are for using at the time of rice cooking, and the usage which assumed the time of rice washing is not made. Further, the automatic rice washing control method disclosed in Patent Document 5 may not be able to cope with other than the preset amount of rice and other than the preset amount of water. That is, it is not possible to automatically detect the amount of rice put in the inner pot and automatically control the washing.

  By the way, the method of washing rice varies depending on each household and individual, and there is no method that everyone recognizes as "correct", and people who practice the method inherited from their parents without any doubt Is almost. In the past, rice milling technology was not as good as it is now, so washing rice has the purpose of removing dirt, such as mud, in addition to the purpose of removing straw during the process of threshing harvested rice into milled rice. There was a general custom of sharpening and washing rice before cooking.

  On the other hand, at present, the rice milling technology has been dramatically improved, and there is a shift from the act of “sharpening” to the recognition that a washing method of “mixing gently in water” is preferable.

  However, most people still practice the “sharpening” of rice inherited from their parents. In some cases, it may be possible to completely remove the rice cake remaining on the surface of the rice by the action of "sharpening" the rice, but this will also remove the nutrients such as vitamins and minerals contained in the rice cake. become. On the other hand, you can taste the delicious taste of rice by leaving the rice cakes. For this reason, even in the production of wash-free rice, a production method that leaves the rice bran has been developed.

Japanese Utility Model Publication No. 62-182132 JP-A-2-213121 JP-A-4-38918 JP-A-4-240421 JP-A-4-158818

  Therefore, the problem of the present invention is that automatic rice washing control according to the amount of washed rice is possible, the amount of rice bran remaining in the rice after washing can be controlled, and the outflow of nutrients contained in rice is suppressed while removing the bad smell It is possible to provide a rice cooker that can be washed with rice to extract the umami of rice.

In order to solve the above problems, the rice cooker of the present invention comprises a rice cooker,
A heating unit for heating the rice cooker;
A stirrer disposed rotatably in the rice cooker;
A rotational drive device for rotationally driving the agitator;
A control unit for controlling the heating unit to perform a heating operation;
A rice amount detection unit for detecting the amount of rice in the rice cooker,
The control unit
Before performing the heating operation by the heating unit, the rice-driving operation for rotating the stirring body by operating the rotary drive device and performing the rice-washing operation according to the amount of rice detected by the rice amount detection unit It has the rice washing operation part which controls the rotational speed which rotationally drives the said stirring body by the said rotational drive apparatus to high and low.

  According to the rice cooker of this invention, the amount of rice in the rice cooker is detected by the rice amount detection unit, and the rice washing operation unit rotates during the washing operation according to the amount of rice detected. The rotational speed at which the stirring member is rotationally driven is controlled to be high or low. Thereby, since the rotation speed of the stirring body at the time of the rice washing operation can be adjusted to the amount of rice to be washed, it is left to the extent that there is rice bran while avoiding the lack of washing rice, and the rotation speed of the stirring body is It is possible to prevent the cracked rice from being too high and maintain the original taste of rice after cooking.

  Also, since the optimal mechanical force according to the amount of rice is added to the rice during washing, the entire rice is agitated, washing unevenness is eliminated, and it is avoided that there is a bias in rice nutrition due to the location of rice in the rice cooker it can. In addition, since the rice washing operation section can automatically wash the rice, it can save the user the trouble of sharpening the rice, especially for the winter when the water is cold and for users who are applying nail art to their nails. There is an advantage that you do not have to put your hands in the water.

Moreover, in the rice cooker of one Embodiment, the said rice washing operation part is
A standard mode in which the rotational speed to be controlled to be high and low is a preset setting value;
An adjustment mode in which the rotational speed controlled to be high or low is increased or decreased by a certain percentage from the set value can be executed,
Furthermore, an input operation unit that can input a signal for causing the rice washing operation unit to execute one of the standard mode and the adjustment mode is provided.

  According to this embodiment, the user can select not only the standard mode but also an adjustment mode in which the degree of washing is changed compared to the degree of washing in the standard mode by operating the input operation unit. . Therefore, the remaining amount of rice bran can be adjusted, and the rice can be washed according to the user's preference.

Moreover, as for the rice cooker of one Embodiment, the said rotational drive device has a drive motor,
The rice quantity detection unit has a motor current detection unit for detecting a current value flowing through the drive motor,
The control unit
Before performing the heating operation by the heating unit, a rice amount detection operation unit that drives the drive motor to rotate the stirring body is provided.

  According to the rice cooker of this embodiment, the rice in the rice cooker is detected by detecting the current value flowing through the drive motor constituting the rotary drive device with the motor current detector of the rice amount detector. The amount of can be detected. That is, the value of current flowing through the drive motor is proportional to the amount of load applied to the drive motor, and the amount of load is proportional to the amount of rice in the rice cooker. It can detect the amount of rice in it.

Moreover, the rice cooker of one Embodiment is equipped with the temperature detection part which detects the temperature of the water in the said rice cooker,
The control unit for washing rice is
According to the temperature detected by the temperature detection unit, the time during which the agitator is rotationally driven by the rotary drive device during the rice washing operation is controlled to be short.

  According to the rice cooker of this embodiment, the rice washing operation unit controls the time for which the stirrer is rotationally driven in accordance with the level of the water temperature during the rice washing operation, so the nutrition of rice after the rice washing The survival rate can be maintained at a certain level. When the water temperature at the time of washing the rice becomes high, the residual nutrient rate after washing tends to decrease.

  Moreover, as for the rice cooker of one Embodiment, the said rice cooker has a water level level scale which shows the amount of water corresponding to the quantity of the rice to wash.

  According to the rice cooker of this embodiment, the user supplies the rice cooker with an amount of water suitable for the amount of rice to be washed by adding water to the rice cooker up to the water level level marked on the rice cooker. it can. For example, it becomes possible to easily supply the rice cooker with a water amount of the washed rice that can maintain the nutrient residual rate of the rice after the washing in a high level.

  Moreover, as for the rice cooker of one Embodiment, the time which the rice-washing operation part of the said control part rotates the said stirring body by the said rotational drive apparatus at the time of the said rice-washing operation is less than 60 second.

  According to the rice cooker of this embodiment, the nutrients of the rice contained in the rice bran existing in the surface layer of the polished rice, more than compared to sharpening the rice by hand without excessively flowing out the rice by washing rice You can definitely leave the nutrients in the rice.

  According to the rice cooker of the present invention, the number of rotations of the stirring body during the rice washing operation can be adjusted to the amount of rice to be washed, so that it remains to the extent that there is rice bran while avoiding the lack of rice washing, and It is possible to prevent the cracked rice from being generated because the rotational speed of the stirring body is too high, and maintain the original taste of the rice after cooking.

FIG. 1 is a longitudinal sectional view schematically showing the overall configuration of an embodiment of a rice cooker according to the present invention. FIG. 2 is a longitudinal sectional view of the inner pot of the rice cooker. FIG. 3 is a control block diagram showing a configuration related to the control unit of the rice cooker. FIG. 4 is a diagram showing the load classification (rice washing amount) corresponding to the current value of the stirring motor. FIG. 5A is a flowchart showing details of rice washing operation (motor current of 0.25 A or less) by the control unit of the rice cooker. FIG. 5B is a flowchart showing details of rice washing operation (motor current exceeds 0.25 A) by the controller of the rice cooker. FIG. 6 is a diagram showing the relationship between the current value flowing through the stirring motor and the amount of rice put in the inner pot when only rice is put in the inner pot. FIG. 7 is a diagram showing the relationship between the current value flowing through the stirring motor when rice and water are put into the inner pot and the amount of rice put into the inner pot. FIG. 8 is a diagram showing the current detected by the motor current detector, the amount of rice corresponding to the detected current, and the minimum rotation speed at which the entire rice in the inner pot moves. FIG. 9 is a diagram showing a state in which the remaining ratio of nutrients in the rice after washing changes depending on the water temperature at the time of washing the rice. FIG. 10 is a characteristic diagram showing the relationship between the bath ratio at the time of washing the rice (the amount of water when the amount of rice is 1) and the residual nutrient ratio after the washing. FIG. 11 is a diagram showing the relationship between the washing time and the nutrient residual rate.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  Drawing 1 is a longitudinal section showing typically the whole composition of the embodiment of the rice cooker concerning the present invention. As shown in FIG. 1, the rice cooker 100 of this embodiment is attached to the upper part of the rice cooker main body 1, the inner pot 2 as a rice cooker accommodated in the rice cooker main body 1, and the upper part of the rice cooker main body 1 so that opening and closing is possible. And a lid 12 that can be closed to cover the inner pot 2 and a heating unit 3 that heats the inner pot 2 housed in the rice cooker body 1. FIG. 1 shows a state where rice 11 is put in the inner pot 2.

  The rice cooker body 1 has an outer case 19 and a housing 20, and the housing 20 is formed of a material having heat resistance and electrical insulation. The housing 20 is supported by the heat insulating member 21 with respect to the outer case 19. The inner pot 2 is formed of, for example, a high heat conductive member such as aluminum, and has an inner surface coated with a fluororesin for preventing adhesion of an object to be heated. As shown in the cross-sectional view of FIG. 2, the inner surface of the inner pot 2 is for washing rice corresponding to the amount of rice (1 go-3 go or 4 go-5.5 go) washed by the rice washing operation described later. A water level level scale 41 for the amount of water is formed. In addition, this water level level scale part 41 is provided separately from the water level level scale (not shown) supplied for rice cooking. This is because the amount of water suitable for washing rice and the amount of water suitable for cooking rice are different.

  The rice cooker 100 includes a stirring motor 4 as a drive motor disposed at the bottom of the outer case 19. A rotor 6 is attached to the rotating shaft 4 a of the stirring motor 4. A cover 22 surrounds the rotor 6 and the rotating shaft 4a. In the rotor 6, a plurality of rotor-side magnets 7 that are drive-side magnets are arranged at equal intervals in the circumferential direction on the outer peripheral portion. The rotor 6 is arranged so as to separate a predetermined gap below a cylindrical convex portion 2a that protrudes inward at the bottom of the inner hook 2. Further, the stirring blade 5 is rotatably fitted to the convex portion 2a of the inner hook 2. The convex portion 2 a of the inner pot 2 serves as a support for the stirring blade 5. The stirring blade 5 includes an annular yoke 9 and a plurality of magnets 8 which are driven side magnets arranged at equal intervals in the circumferential direction inside the yoke 9. The magnet 8 on the stirring blade 5 side is disposed so as to face the magnet 7 of the rotor 6 in the radial direction. The stirring blade 5 has a magnet 14 at the center upper portion, and this magnet 14 attracts the magnet 7 of the rotor 6 and plays a role of holding the stirring blade 5 on the convex portion 2 a of the inner pot 2.

  Therefore, when the rotating shaft 4a of the stirring motor 4 rotates, the magnet 7 of the rotor 6 rotates, and the magnet 8 magnetically coupled to the magnet 7 rotates, whereby the stirring blade 5 rotates.

  The heating unit 3 is supported and attached to the housing 20 by attachment members 23 and 24 that are insulators and heat insulators. The heating unit 3 includes a heat transfer heater and an induction coil. When an induction coil is used, a magnetic material such as stainless steel, which improves the heating efficiency, is attached to the outer surface of the inner pot 2.

  Moreover, the temperature sensor 10 is attached to the housing 20, and the detection unit 10 a of the temperature sensor 10 passes through the heating unit 3 and contacts the bottom of the inner pot 2 to detect the temperature of the inner pot 2. The temperature sensor 10 can indirectly detect the temperature of the water put in the inner pot 2 by detecting the temperature of the inner pot 2.

  FIG. 3 is a control block diagram of the rice cooker 100. The rice cooker 100 includes a control unit 31 including a microcomputer and an input / output circuit. Based on an operation signal from the operation panel 32, a signal from the temperature sensor 10, and the like, the display unit 33, the agitation motor 4, and the heating unit. 3 heating circuit 35 is controlled. The operation panel 32 and the display unit 33 are provided on the front side of the rice cooker body 1, and a cooking menu, cooking status, and the like can be displayed on the liquid crystal display of the display unit 33 by a plurality of operation buttons on the operation panel 32. . Moreover, the control part 31 is arrange | positioned in the space between the outer case 19 and the housing | casing 20 of the rice cooker main body 1. FIG. The heating circuit 35 is included in a power supply unit (not shown) disposed between the outer case 19 of the rice cooker body 1 and the housing 20.

  The rice cooker 100 also has a motor current detection unit 36 that detects the value of the current flowing through the stirring motor 4. The motor current detection unit 36 forms a rice amount detection unit that detects the amount of rice in the inner pot 2. That is, the value of the current flowing through the stirring motor 4 is proportional to the amount of load applied to the stirring motor 4, and this load is proportional to the amount of rice in the inner pot 2. It can detect the amount of rice in it. As shown in an example in FIG. 4, when the amount of rice in the inner pot 2 is 2 go or less, the value of the current flowing through the stirring motor 4 is 0.25 A or less, and the amount of rice in the inner pot 2 is 4 The current value flowing through the agitating motor 4 is 0.3A or less when it is equal to or less than 0.35A, and the current value flowing through the agitating motor 4 is 0.35A when the amount of rice in the inner pot 2 is 5.5 or less. It is as follows.

  Further, the control unit 31 has a rice washing operation unit 37. The rice washing operation unit 37 performs the rice washing operation by driving the stirring motor 4 and rotating the stirring blade 5 before controlling the heating circuit 35 and performing the heating operation by the heating unit 3. This rice washing operation is executed by operating the operation panel 32. In addition, the control unit 31 includes a rice quantity detection operation unit 38. Before performing the rice washing operation by the rice washing operation unit 37, the rice amount detection operation unit 38 performs the rice amount detection operation by driving the stirring motor 4 and rotating the stirring blade 5 for a predetermined time.

  Next, the operation of performing the rice amount detection operation and the automatic rice washing operation before cooking rice by heating with the electric rice cooker having the above configuration will be described with reference to the flowcharts of FIGS. 5A and 5B. In addition, although all the measured values used in this description are the values obtained by experiment, it is an illustration and is not this limitation.

  First, a user puts a desired amount of rice 11 into the inner pot 2 and stores the inner pot 2 containing the rice 11 in the rice cooker body 1. Next, the user operates the operation panel 32 to select a rice washing mode for performing the rice washing operation (step S1). Next, it progresses to step S2, and the control part 31 judges whether the lid | cover 12 is closed, and when it judges that the lid | cover 12 is closed, it will progress to step S3. Whether or not the lid 12 is closed is confirmed, for example, by turning on (or off) when a limit switch provided on the lid 12 abuts against a contacted portion provided on the inner hook 2.

  Next, in step S3, the control unit 31 drives the agitation motor 4 to rotate the agitation blade 5 at a constant rotation speed (400 rpm in this example). At this time, the motor current detection unit 36 shown in FIG. Detects the current flowing through the stirring motor 4. If the detected current is 0.25 A or less, the process proceeds to step S4, and if the detected current exceeds 0.25 A, the process proceeds to step S9. In step S9, it is determined whether or not the current detected by the motor current detector 36 is 0.3 A or less. If it is determined that the detected current is 0.3 A or less, the process proceeds to step S10, where the detected current is 0. If it is determined that it exceeds .3A, the process proceeds to step S15. In step S15, it is determined whether or not the detected current is 0.35 A or less. If it is determined that the detected current is 0.35 A or less, the process proceeds to step S16, and the detected current exceeds 0.35 A. If it is determined, the process proceeds to step S21. In step S21, the display unit 33 (shown in FIG. 3) displays that the load is over and stops the operation in the rice washing mode. In addition, step S3, step S9, and step S15 comprise the rice quantity detection driving | operation part.

  When the load detection of the stirring motor 4 is completed in the above-described steps S3, S9, and S15, water is supplied to the inner pot 2. That is, according to FIG. 4 as an example, when the current detected in step S3 is 0.25 A or less, the amount of rice in the inner pot 2 is 2 or less. In this case, the control unit 31 causes the display unit 33 to display that the amount of rice in the inner pot 2 is 2 go or less. The user may put water up to a water level level scale 41b representing the amount of water corresponding to 1-3, which is stamped on the inner surface of the inner pot 2, for example. In addition, the control unit 31 executes the next step S5 or step S6 in which the rotation speed of the stirring motor 4 is set to 350 rpm.

  Further, when the current detected in step S9 is 0.3 A or less, according to FIG. 4 as an example, the amount of rice in the inner pot 2 is greater than 2 go but less than 4 go. In this case, the control unit 31 causes the display unit 33 to display that the amount of rice in the inner pot 2 exceeds 2 go but is 4 go or less. By looking at this display, for example, the user may add water up to a water level scale 41a indicating the amount of water corresponding to 4 go-5.5 go stamped on the inner surface of the inner pot 2. In this case, the next step S11 or step S12 in which the rotation speed of the stirring motor 4 is set to 450 rpm is executed.

  Further, when the current detected in step S15 is less than 0.35 A, according to FIG. 4 as an example, the amount of rice in the inner pot 2 is greater than 4 go but less than 5.5 go. In this case, the control unit 31 causes the display unit 33 to display that the amount of rice in the inner pot 2 exceeds 4 go but is less than 5.5 go. By looking at this display, for example, the user may add water to the water level of the water level scale 41a indicating the amount of water corresponding to 4 go-5.5 go imprinted on the inner surface of the inner pot 2. In this case, the next step S17 or step S18 in which the rotation speed of the stirring motor 4 is set to 550 rpm is executed.

  Thus, water is supplied to the inner hook 2 after detecting the load of the stirring motor 4 in the above-described steps S3, S9, and S15, and the process proceeds to the next steps S4, S10, and S16 to be supplied to the inner pot 2. The temperature of the water is detected by the temperature sensor 10. The temperature sensor 10 detects the temperature of the water in the inner pot 2 indirectly by detecting the temperature of the inner pot 2. In step S4, step S10, and step S16, it is determined whether the temperature of the water detected by the temperature sensor 10 is less than 23 ° C. If it is determined that the temperature is less than 23 ° C, the process proceeds to step S5, step S11, and step S17. If it is determined that the temperature is not less than 23 ° C., the process proceeds to step S6, step S12, and step S18. Note that the temperature of 23 ° C. is an example of a criterion.

  In step S5, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotational speed of 350 rpm for 60 seconds. Moreover, in step S6, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotational speed of 350 rpm for 30 seconds. In step S11, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotation speed of 450 rpm for 60 seconds. In step S12, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotation speed of 450 rpm for 30 seconds. In step S17, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotational speed of 550 rpm for 60 seconds. Moreover, in step S18, the rice 11 in the inner pot 2 is washed by driving the stirring motor 4 at a rotational speed of 550 rpm for 30 seconds.

  As described above, the driving time of the stirring motor 4 is controlled to be short and long (for example, 30 seconds and 60 seconds) according to the temperature of the water in the inner pot 2 being high and low (for example, 23 ° C. or more and less than 23 ° C.). Therefore, it is possible to set the washing time suitable for the water temperature of washed rice, and the washed rice can be executed without excess or deficiency.

  Further, according to the value of the detected current representing the amount of rice detected in step S3, if the detected current is a relatively small amount of rice (for example, 2 go or less) of 0.25 A or less, the rotation speed of the agitating motor 4 is set. 350 rpm is set (steps S5 and S6). In addition, when the detected current exceeds 0.25A in step S9 but is a moderate amount of rice of 0.3A or less (for example, more than 2 joints but 4 joints or less), the rotation speed of the agitating motor 4 is set. 450 rpm is set (steps S11 and S12). Further, when the detected current is a relatively large amount of rice of 0.3A or more and less than 0.35A in step S15 (for example, more than 4 go but less than 5.5 go), the rotation speed of the agitating motor 4 is 550 rpm. (Steps S17 and S18). In this way, in the rice washing operation, the more the amount of rice 11 in the inner pot 2 is, the higher the rotation speed of the stirring motor 4 is controlled. Therefore, the number of rotations of the stirring blade 5 suitable for the amount of rice can be set. Can be executed without excess or deficiency. In addition, the rotation speed of the stirring motor 4 can be controlled using an inverter circuit etc. as an example.

  In steps S5, S6, S11, S12, S17, and S18, the stirring motor 4 is driven for the above-described driving time, and then the stirring motor 4 is turned off (steps S7, S13, and S19).

  Thereafter, in steps S8, S14, and S20, the user is notified that the rice washing process has been completed. The end notification of the rice washing process is performed by display on a display unit 33 (shown in FIG. 3) provided together with the operation panel 32 or by a notification sound from a notification sound source (not shown) disposed in the outer case 19.

  Next, in FIG. 6, when only rice is put in the inner pot 2 and the stirring motor 4 is rotated at 400 rpm, the current value (A) flowing through the stirring motor 4 detected by the motor current detection unit 36 and the inner value The experimental result which calculated | required the relationship with the quantity (total) of the rice put into the pot 2 is shown. From FIG. 6, it can be seen that the current value detected by the motor current detector 36 increases in proportion to the amount of rice in the inner pot 2. That is, it can be seen that the amount of rice in the inner hook 2 can be accurately detected by the motor current detection unit 36. Next, in FIG. 7, when rice and water are put into the inner pot 2 and the stirring motor 4 is rotated at 400 rpm, the current value (A) flowing through the stirring motor 4 detected by the motor current detection unit 36 is The experiment result which calculated | required the relationship with the quantity (total) of the rice put into the inner pot 2 is shown. Here, the amount of water to be put into the inner pot 2 is set, for example, according to a water level level scale 41 for washing rice, which is stamped on the inner peripheral surface of the inner pot 2 shown in FIG. As shown in FIG. 7, even when not only rice but also water is put in the inner pot 2, the amount of rice in the inner pot 2 can be accurately detected by the current value detected by the motor current detecting unit 36. I understand.

  In the above experiment, the rotation time of the stirring blade 5 for detecting the amount of rice may be about 10 seconds. This 10 seconds is the shortest time during which the motor current detector 36 can detect the amount of rice. Turning the stirring blade 5 for an excessively long time with only the rice in the inner pot 2 will cause cracked rice, and if the stirring blade 5 is turned for a long time with the rice and water in it, There is a possibility of losing nutrition.

  Next, the table shown in FIG. 8 shows the current value detected by the motor current detection unit 36 in the left column, and the amount of rice in the inner pot 2 detected corresponding to the detected current value. Shown in the middle column. In the right column of the table of FIG. 8, when the amount of rice detected is the minimum amount that the entire rice moves in the inner pot 2 when the stirring blade 5 is rotated in the inner pot 2. The rotation speed is shown. The smaller the amount of rice in the inner pot 2, the higher the minimum number of revolutions that will move the whole rice. Therefore, at the time of washing the rice, the larger the amount of rice in the inner pot 2, the higher the number of revolutions of the stirring motor 4, so that even if the amount of rice in the inner pot 2 is larger, all the rice in the inner pot 2 is stirred. It can be moved by the rotation of the wing 5. Therefore, it becomes possible to eliminate washing unevenness due to the location of the rice 11 in the inner pot 2. Further, by setting the rotation speed of the agitating motor 4 to the smallest rotation speed (the value in the right column of the table of FIG. 8) among the rotation speeds in which the entire rice moves, it is possible to avoid giving extra mechanical force to the rice. . Thereby, generation | occurrence | production of cracked rice can be prevented. Further, the stirring blade 5 rotating at high speed can substantially eliminate the trouble that water is scattered and the surroundings are soiled during washing.

  By the way, the amount of nutrients remaining in the rice varies depending on the temperature of the water when washing the rice. That is, the lower the water temperature at the time of washing the rice, the easier the nutrition remains in the rice after the washing. On the other hand, at a water temperature of about 23 ° C. or higher, the nutrient outflow state is not significantly different. FIG. 9 shows how the residual rate of remaining nutrients in the rice after washing changes depending on the water temperature at the time of washing the rice. The characteristics K1, K2, and K3 in FIG. 9 show the relationship between the residual nutrient amount of rice and the water temperature at the time of washing when the amount of rice at the time of washing is 1 go, 3 go, and 5.5 go, respectively. It can be said in common that the amount of rice at the time of washing is 1 go (characteristic K1), 3 go (characteristic K2), 5.5 go (characteristic K3) when the water temperature is 7 ° C and when the water temperature is 23 ° C. Therefore, the residual rate of nutrition differs by about 10%. That is, nutrition is more likely to remain after the rice washing when the water temperature is 7 ° C. than when the water temperature is 23 ° C. Further, in 1 go (characteristic K1) and 3 go (characteristic K2), the residual ratio of nutrients is substantially constant between a water temperature of 23 ° C. and a water temperature of 38 ° C., and does not drop greatly. On the other hand, at 5.5 (characteristic K3), the nutrient residual rate decreases between a water temperature of 23 ° C. and a water temperature of 38 ° C.

  Therefore, for example, when the water temperature detected by the temperature sensor 10 is less than 23 ° C., the time for rotating the stirring blade 5 at the time of washing the rice is set as the standard rotation time, and if the water temperature is 23 ° C. or more, it is shorter than the standard rotation time. The rice washing operation control is performed by the rice washing operation unit 37. As an example, as described with reference to the flowcharts of FIGS. 5A and 5B, the standard rotation time is 60 seconds, and when the water temperature detected by the temperature sensor 10 is less than 23 ° C., the rotation time of the stirring blade 5 is 60 When the water temperature detected by the temperature sensor 10 is 23 ° C. or higher, the rotation time of the stirring blade 5 is set to 30 seconds. As described above, the rotation time of the stirring blade 5 (driving time of the stirring motor 4) is short and long (30 seconds, 60 seconds) according to the high and low water temperature (23 ° C. or more and less than 23 ° C.) at the time of washing the rice To control. By controlling this rotation time, the surface of the rice is not excessively shaved during the rice washing, and even when the water temperature is 23 ° C. or higher, a nutrient equivalent to the case where the water temperature is 7 ° C. can be left in the rice after the rice washing. it can. In this embodiment, when controlling the rotation time of the stirring blade 5 during the rice washing operation, the water temperature is determined with a water temperature of 23 ° C. as a boundary. However, the water temperature at the boundary of the water temperature determination is limited to only 23 ° C. Of course not. That is, you may set several rotation time of the stirring blade 5 according to the water temperature at the time of rice washing. For example, when the water temperature is 23 ° C. or more, the rotation time of the stirring blade 5 is set to 20 seconds, and when the water temperature is 15 ° C. or more and less than 23 ° C., the rotation time of the stirring blade 5 is set to 30 seconds. When the temperature is less than 15 ° C., the rotation time of the stirring blade 5 may be set to 45 seconds, and when the water temperature is less than 10 ° C., the rotation time of the stirring blade 5 may be set to 60 seconds.

  Moreover, when the amount (volume) of water required when the amount (volume) of rice to be washed is 1 is defined as a bath ratio, there is a bath ratio that minimizes the outflow of nutrients at the time of washing the rice. FIG. 10 shows the nutrient residual rate of rice after washing with different bath ratios. The characteristic K11 in FIG. 10 shows the relationship between the bath ratio and the nutrient residual rate when the rice washing time (rotation time of the stirring blade 5) is 30 seconds, and the characteristic K12 in FIG. 10 shows the rice washing time (rotation time of the stirring blade 5). ) Shows the relationship between the bath ratio and nutrient residual rate when 60 seconds. In addition, it is magnesium that is nutrition here. According to the plots P11 and P12 of the characteristics K11 and K12 in FIG. 10, when the bath ratio is 2.2, the nutrition is most likely to remain after the rice washing. On the other hand, the plots L11 and L12 when the bath ratio value is 1.6 and the plots R11 and R12 when the bath ratio value is 6.7 are shown when the bath ratio is smaller than 2.2 and when the bath ratio is 2. If it is greater than .2, it indicates that nutrition tends to flow out easily.

  Therefore, it is preferable that the water level level scale for the rice washing formed in the inner pot 2 is set so as to have a bath ratio that maximizes the nutrient residual rate for each amount of rice washing. In this embodiment, the optimum value of the bath ratio is 2.2. However, if the bath ratio is set to 2.2 when the amount of washed rice is large, water may overflow from the inner pot 2. In that case, it is necessary to reduce the amount of water, and the bath ratio decreases accordingly, but it may be set so as to be the minimum necessary amount.

  Further, in this embodiment, as described above, the standard rotation time of the stirring blade 5 at the time of washing is 60 seconds. FIG. 11 shows the relationship between the rice washing time by automatic rice washing (rotation time of the stirring blade 5) and the nutrient residual rate. According to FIG. 11, the nutrient amount is reduced by about 20% by the automatic rice washing for 10 seconds as compared to before the rice washing, and the nutrition amount is reduced by about 40% by the automatic rice washing for 60 seconds compared to before the rice washing. Yes. However, the rice after the automatic washing for 60 seconds has a nutrient amount 1.5 times that of the hand-washed rice. And after automatic rice washing for 10 minutes, the amount of nutrients has decreased about 60% compared with before rice washing, and the nutrient residual rate has fallen compared with hand-washed rice.

  Therefore, it can be seen from FIG. 11 that it is possible to ensure a large amount of residual nutrient compared to hand-washed rice when the washing time of automatic rice washing is within 60 seconds. Therefore, when controlling the rice washing time in order to leave nourishment in the rice, it is desirable to set the optimum value of the rice washing time within 60 seconds.

  And the rice washed with the rice washing time within 60 seconds was cooked by the heating cooking operation described below, and the taste was confirmed. As a result, when the rice washing time is 60 seconds and the rice washing time is 30 seconds, both are not particularly smelly compared to hand-washed rice, but rather taste the flavor of rice compared to hand-washed rice It was confirmed that is possible.

  Next, an example of the operation of cooking rice after washing the rice 11 in the inner pot 2 by the above-described automatic rice washing operation will be described below. First, after the rice washing, the water used for the rice washing is discarded. Then, after the rice after washing and the water for rice cooking are newly put in the inner pot 2 and the inner pot 2 is stored in the rice cooker body 1, the user operates the operation panel 32 to cook (cooking rice). The operation is started, and the control unit 31 determines whether or not the lid 12 is closed. When the control unit 31 determines that the lid 12 is closed, the heating circuit 35 controls the heating unit 3 to heat the cooking unit 3 (rice cooking). ).

  In this cooking operation, the control unit 31 performs control in the order of preheating operation, start-up operation, cooking operation, steaming operation, and heat retaining operation.

[Preheating operation]
First, in the preheating operation, the stirring blade 5 is rotationally driven by the stirring motor 4, and a small electric power is supplied from the heating circuit 35 to the heating unit 3 while stirring the inside of the inner pot 2. And the power of the heating unit 3 is controlled so as to keep the temperature in the inner pot 2 detected by the temperature sensor 10 at 60 ° C., and the preheating operation is performed for a predetermined time. At this time, by stirring the inside of the inner pot 2 with the stirring blade 5, the rice to be heated (rice and water) in the inner pot 2 is allowed to absorb water while maintaining a uniform target temperature (60 ° C). Glucose, an umami component, is produced.

  In this preheating operation, it is set to 60 ° C., which is the temperature at which the amylolytic enzyme works most effectively, and the temperature in the inner pot 2 is kept at 60 ° C. for 15 minutes to 20 minutes. In this embodiment, the target temperature of the preheating operation is set to 60 ° C. However, the present invention is not limited to this, and the target temperature may be set as appropriate according to various conditions.

[Start-up operation]
Next, after the operation of the stirring motor 4 is stopped and the stirring blade 5 is stopped, a large electric power is supplied from the heating circuit 35 to the heating unit 3, and the inner pot 2 is heated by the heating unit 3. A start-up operation is performed in which the temperature of the is raised to 100 ° C. Here, the temperature in the inner pot 2 is detected by the temperature sensor 10.

[Cooking operation]
Next, after the temperature in the inner pot 2 reaches 100 ° C., the cooking operation is performed in which the heating amount by the heating unit 3 is adjusted and boiling is maintained until the temperature in the inner pot 2 reaches 120 ° C. Here, when the water in the inner pot 2 runs out and it stops boiling, the temperature in the inner pot 2 starts to rise from 100 ° C. By this cooking operation, heat and water are added to the rice to cause a chemical reaction called gelatinization in which β starch contained in the rice is changed to α starch, and delicious rice can be produced.

[Steaming operation]
Then, when the temperature in the inner pot 2 reaches 120 ° C., the amount of heating by the heating unit 3 is adjusted and the steaming operation is performed for a predetermined time. Then, the cooking (rice cooking) is finished, and the heat retaining operation is started.

  As described above, according to the rice cooker of the present embodiment, the amount of rice in the inner pot 2 is detected by detecting the current value flowing through the stirring motor 4 by the motor current detecting unit 36, and the rice 11 in the inner pot 2 is detected. The larger the amount, the higher the number of revolutions of the stirring motor 4 in the rice washing operation is controlled. Therefore, the number of revolutions of the stirring blade 5 suitable for the amount of rice can be set, and the washing of rice can be performed without excess or deficiency. In addition, since the drive time of the agitating motor 4 is controlled to be short and long according to the high and low temperature of the water in the inner pot 2 detected by the water temperature sensor 10, it is possible to set the rice washing time suitable for the washing water temperature. , Can wash the rice without excess or deficiency. Therefore, it is possible to maintain the original taste of rice after cooking by preventing rice from being washed to the extent that rice bran remains and preventing the generation of cracked rice due to the high rotation speed of the stirring blade 5. Become.

  In the above embodiment, the motor current detection unit 36 that detects the value of the current flowing through the agitation motor 4 is the rice amount detection unit, but the moving member is attached to the bottom of the inner hook 2 with a spring member or the like with respect to the housing 20. The amount of rice in the inner hook 2 may be detected by measuring the amount of displacement of the moving member that is supported so as to come into contact and is displaced according to the amount of rice in the inner hook 2 with a strain amount measuring device. Moreover, in the said embodiment, although the rotation speed of the stirring motor 4 was adjusted to high and low in steps according to the detected amount of rice, the rotation speed of the stirring motor 4 was continuously adjusted to high and low according to the amount of rice. May be. Moreover, in the said embodiment, although the rotation time of the stirring motor 4 was controlled in short steps according to the temperature detected with the water temperature sensor 10, the rotation time of the stirring motor 4 was continuously shortened according to the detected water temperature. May be controlled automatically.

  Moreover, in the said embodiment, the rotation speed of the stirring blade 5 which the control part 31 controls according to the detected rice quantity is a series of rice set for the rice washing without excess and deficiency as demonstrated with the above-mentioned flowchart. The number of rotations (350 rpm, 450 rpm, 550 rpm) was used, but the user may be able to adjust the number of rotations (350 rpm, 450 rpm, 550 rpm). For example, when the operation panel 32 as an input operation unit is provided with buttons such as “light”, “standard”, “careful”, etc. for specifying the degree of rice washing as the rice washing menu, and the “standard” button is pressed. Executes each rotation speed described in each step of the above-mentioned flowchart, and when the “light” button is pressed, as an example, the number of rotations (350 rpm, 450 rpm, 550 rpm) in the above-described flowchart is an example. When the rotation speed 10% lower is executed and the “careful” button is pressed, the rotation speed 10% higher than the series of rotation speeds in the above-described flowchart may be executed as an example. Thereby, the user can adjust the remaining amount of rice bran, and the rice can be washed according to the user's preference. It should be noted that the rotational speed may be adjusted not only in three stages of “light”, “standard”, and “careful” but also in multiple stages.

  Further, in the above embodiment, the rotation is transmitted from the stirring motor 4 to the stirring blade 5 by the magnetic coupling using the magnet 7 of the rotor 6 and the magnet 8 of the stirring blade 5, but instead of the magnetic coupling by the magnets 7, 8. When the inner pot 2 is housed in the rice cooker body 1, the stirring blade 5 may be mechanically fitted to the rotor 6 attached to the rotating shaft 4 a of the stirring motor 4 so as not to be relatively rotatable. In this case, a seal device for preventing water leakage is provided at a location penetrating the inner hook 2 by a structure in which the stirring blade 5 and the rotor 6 are fitted. Further, instead of the stirring motor 17 and the rotor 6, for example, a stator yoke of a synchronous motor, a plurality of coils wound around the stator yoke, and a rotating magnetic field for generating a rotating magnetic field in the plurality of coils. An AC power source may be used. By generating a rotating magnetic field by the stator yoke and the AC power source, the magnetically coupled stirring blade 5 can be driven to rotate.

  In addition, this invention is not limited to the said embodiment, A various change can be implemented within the scope of this invention.

DESCRIPTION OF SYMBOLS 1 Rice cooker main body 2 Inner pot 2a Convex part 3 Heating part 4 Stirring motor 4a Rotating shaft 5 Stirring blade 6 Rotor 7 Rotor side magnet 8 Stirring blade side magnet 9 Yoke 10 Temperature sensor 10a Detection part 11 Rice 12 Cover 14 Magnet 19 Outer case 20 Case 21 Heat insulation member 22 Cover 23, 24 Mounting member 31 Control unit 32 Operation panel 33 Display unit 35 Heating circuit 36 Motor current detection unit 37 Rice washing operation unit 38 Rice amount detection operation unit 41 Water level scale unit 41a, 41b Water level level scale 100 rice cooker

In order to solve the above problems, the rice cooker of the present invention comprises a rice cooker,
A heating unit for heating the rice cooker;
A stirring body for stirring the rice in the rice cooker;
A rotational drive device for rotationally driving the agitator;
A control unit for controlling the heating unit to perform a heating operation ;
With
The control unit
According to the amount of rice in the rice cooker, it has a rice washing operation section that changes the number of rotations that rotate the stirring body by the rotation driving device so that cracked rice does not occur during the rice washing operation. .

Claims (6)

A rice cooker,
A heating unit for heating the rice cooker;
A stirrer disposed rotatably in the rice cooker;
A rotational drive device for rotationally driving the agitator;
A control unit for controlling the heating unit to perform a heating operation;
A rice amount detection unit for detecting the amount of rice in the rice cooker,
The control unit
Prior to performing the heating operation by the heating unit, the rotary drive device is operated to perform the rice washing operation for rotating the agitator and at the time of the rice washing operation according to the amount of rice detected by the rice amount detection unit. A rice cooker comprising a rice washing operation unit that controls the rotational speed of the stirring body to be rotationally driven by the rotational driving device. In the rice cooker according to claim 1,
The rice washing operation section
A standard mode in which the rotational speed to be controlled to be high and low is a preset setting value;
An adjustment mode in which the rotational speed controlled to be high or low is increased or decreased by a certain percentage from the set value can be executed,
The rice cooker further includes an input operation unit capable of inputting a signal for causing the rice washing operation unit to execute one of the standard mode and the adjustment mode. In the rice cooker according to claim 1 or 2,
The rotational drive device has a drive motor,
The rice quantity detection unit has a motor current detection unit for detecting a current value flowing through the drive motor,
The control unit
A rice cooker having a rice amount detection operation unit that drives the drive motor to rotate the stirring body before performing the rice washing operation by the rice washing operation unit. In the rice cooker as described in any one of Claim 1 to 3,
A temperature detection unit for detecting the temperature of the water in the rice cooker,
The control unit for washing rice is
According to the temperature detected by the temperature detection unit, the time during which the agitator is rotationally driven by the rotational driving device during the rice washing operation is controlled to be short. In the rice cooker as described in any one of Claim 1 to 4,
The above rice cooker is
A rice cooker having a water level scale indicating the amount of water corresponding to the amount of rice to be washed. In the rice cooker as described in any one of Claim 1 to 5,
The rice cooker characterized in that the rice washing operation unit of the control unit rotates the stirrer by the rotation driving device during the rice washing operation within 60 seconds.

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