JP5965818B2 - Cooker - Google Patents

Description

  The present invention relates to a cooking device such as a rice cooker that can promote rice water absorption and suppress uneven cooking during the initial stage of the rice cooking process.

  Rice contains carbohydrates, minerals, proteins, dietary fiber, lipids, and the like, and has been reconsidered as a healthy food in recent years because it is low in calories. Under such circumstances, various rice cookers have been developed to cook delicious rice.

  General rice cookers put rice after washing into a rice cooker, add a predetermined amount of water, set it in the rice cooker, start cooking rice, detect the temperature of the rice cooker and control the heating The water absorption heating process and the water absorption process for absorbing water into the rice in advance, the boiling heating process for raising the temperature to the boiling temperature, and the boiling process for sufficiently α-izing the rice while further absorbing water Perform the steaming process.

  In addition, with the recent diversification of consumer preferences, general rice cookers change the time or temperature of each of the above processes, or the amount of water, to change the hardness and stickiness of cooked rice that meets consumer preferences. A cooking sequence is provided.

  In Patent Document 1 (Japanese Patent Laid-Open No. Sho 62-144606), Patent Document 2 (Japanese Patent No. 3112270 Publication), and Patent Document 3 (Japanese Patent Laid-Open Publication No. 2011-183085), rice can be stirred inside a rice cooker. There has been disclosed a rice cooker that is provided with an agitating mechanism and is capable of temperature equalization during rice cooking (prevention of temperature unevenness) and shortening of rice cooking time.

JP-A-62-144606 Japanese Patent No. 3112270 JP 2011-183085 A

  By the way, in a normal rice cooker, the temperature of the rice inside the rice cooker has a temperature difference between the upper and lower sides when the kettle is viewed from the side and the middle and outer sides when the kettle is viewed from the top. In order to suppress this temperature difference, it is necessary to moderate the temperature rise during heating or to directly stir the interior together with the temperature rise heating.

  In patent document 1, patent document 2, and patent document 3, although the temperature equalization during rice cooking and the shortening of rice cooking time can be achieved by driving the stirring mechanism provided inside the rice cooker, Not mentioned.

  Generally, when heating is performed with high heating power in order to quickly raise the temperature while stirring, if the stirring during heating is weak, unevenness in the temperature of the rice inside the rice cooker tends to occur. On the other hand, if the agitation is too strong, a lot of solids such as glue are eluted from the rice, and if this amount of eluted solids is large, problems such as stickiness and scorching may occur in the finished rice after cooking. From the survey of

  Then, the subject of this invention is providing the heating cooker which can suppress the generation | occurrence | production of stickiness, a burning, etc. in the finishing of the rice after cooking, suppressing the uneven cooking of rice while promoting the water absorption to rice. There is.

In order to solve the above problems, the heating cooker of the present invention is:
A rice cooker for storing a heated object including rice and water;
A stirring mechanism for stirring the object to be heated in the rice cooker;
A motor for driving the stirring mechanism to stir the object to be heated;
A heating unit for heating the rice cooker;
A temperature sensor for detecting the temperature of the object to be heated;
A heating control unit that controls the heating unit based on the output of the temperature sensor so that the temperature of the object to be heated becomes a predetermined temperature;
A rotational speed detecting means for detecting the rotational speed of the motor;
A speed control unit that controls the motor based on the output of the rotational speed detection means so that the rotational speed of the motor becomes a predetermined rotational speed;
The speed controller is
In the water absorption heating step of heating the object to be heated from room temperature to a set temperature, a drive input value for driving the motor while raising the temperature from room temperature to the first temperature is set from the first temperature to the set temperature. It is characterized by having a drive input means for making it larger than the drive input value for driving the motor while the temperature is raised up to.

  Here, the drive input value is a duty ratio of PWM control, a voltage value of voltage control, a current value of current control, or the like.

  According to the heating cooker of the present invention, in the water absorption heating process in which the rice and water are heated from normal temperature to the set temperature by the drive input means of the speed control unit, the temperature is increased from normal temperature to the first temperature. The drive input value for driving the motor is set larger than the drive input value for driving the motor while the temperature is raised from the first temperature to the set temperature.

  In this way, by increasing the stirring until the temperature of the rice and water reaches the first temperature, the temperature can be quickly raised, water absorption into the rice can be promoted, and uneven rice cooking can be suppressed. On the other hand, after the temperature of the rice and water reaches the first temperature, the amount of solids eluted from the rice is reduced by weakening the agitation, and there are problems such as stickiness and scorching in the finished rice after cooking. Occurrence can be prevented.

Moreover, in the heating cooker of one embodiment,
The heating control unit
In the water absorption heating step, a driving input value for driving the heating unit while the temperature is raised from normal temperature to the first temperature is driven, and the heating unit is driven while the temperature is raised from the first temperature to the set temperature. Drive input means for making the drive input value larger than the drive input value.

  According to the heating cooker of this embodiment, the drive input for driving the heating unit during the temperature rising from the normal temperature to the first temperature in the water absorption heating step by the drive input unit of the heating control unit. The value is set to be larger than the drive input value for driving the heating unit while the temperature is raised from the first temperature to the set temperature.

  Thus, the temperature of rice and water can be raised more rapidly by increasing the heating power until the temperature of rice and water reaches the first temperature. On the other hand, after the temperature of rice and water reaches the first temperature, overshooting of the temperature of rice and water can be prevented by reducing the heating power.

  Moreover, in the heating cooker of one Embodiment, the said 1st temperature is temperature which the amount of elution solid content increases.

  Here, the temperature at which the eluted solid content increases means the temperature at which the eluted solid content increases critically.

  According to the heating cooker of this embodiment, since the first temperature is a temperature at which the amount of the eluted solid content increases, after reaching the increased temperature of the amount of the eluted solid content, by weakening the stirring, The amount of eluted solids can be reduced more reliably.

  According to the heating cooker of the present invention, the motor is driven while the temperature is raised from the normal temperature to the first temperature in the water absorption heating step of heating the rice and water from the normal temperature to the set temperature by the speed control unit. The driving input value for the purpose is larger than the driving input value for driving the motor while the temperature is raised from the first temperature to the set temperature, thereby promoting water absorption into the rice and uneven rice cooking In addition, it is possible to prevent the occurrence of problems such as stickiness and scorching in the finished rice after cooking.

It is a schematic block diagram of the rice cooker as an example of the heating cooker of this invention. It is a block diagram of the control apparatus of a rice cooker. It is a figure which shows each process and temperature history of a rice cooker. It is a figure which shows the operation | movement and temperature history of the rotary body of a stirring mechanism of a rice cooker, and a stirring blade. It is a figure which shows control of the rotation speed of a stirring blade and the output of a heater in a water absorption heating process. It is a schematic block diagram which shows the test apparatus which measures the amount of elution solid content. It is a figure which shows the result measured using the said test apparatus. It is a figure which shows the other control of the rotation speed of the stirring blade in a water absorption heating process, and the output of a heater.

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

  FIG. 1 is a schematic configuration diagram of a rice cooker as an example of a heating cooker according to the present invention. As shown in FIG. 1, this rice cooker is connected to the main body 1 so that it can be opened and closed by a main body 1 having an opening, a rice cooker 2 accommodated in the main body 1, a pivot (hinge shaft) and a latch mechanism (not shown). And a lid 3.

  The lid 3 is provided with an inner lid 4, and a lid heater 5 and a lid temperature sensor 6 are further provided inside the inner lid 4. The inner lid 4 is provided with a rotating shaft 7 that passes through the inner lid 4 and the lid heater 5 in a non-contact manner, and a rotating body 8 that can rotate in synchronization with the rotating shaft 7.

  The rotating body 8 is provided with a stirring blade 9 that stands (develops) and falls over the rotating body 8. The rotary shaft 7 is connected to a motor (not shown in FIG. 1) inside the lid 3 so that the rotary body 8 and thus the stirring blade 9 can be driven to rotate.

  The stirring blade 9 receives the rotational force from the rotating shaft 7 through a gear mechanism including a bevel gear (not shown), and rises (deploys) and falls (accommodates) in accordance with normal rotation and reverse rotation of the rotating shaft 7. ). The agitating blade 9 stands up from the rotating body 8, that is, rotates in conjunction with the rotating body 8 in a deployed state so that the water and rice accommodated in the rice cooker 2 are agitated by the agitating blade 9. It has become.

  The details of the gear mechanism are not the gist of the present invention and are well known in Japanese Patent Application Laid-Open No. 2012-135605 and the like, and thus detailed description thereof is omitted.

  The rotating body 8, the gear mechanism, and the stirring blade 9 constitute an example of the stirring mechanism 20. However, the stirring mechanism may be anything as long as it can stir the rice and water in the rice cooker 2, for example, the stirring mechanism described in Patent Documents 1 to 3.

  The casing of the lid 3 has a steam port 13 for escaping water vapor generated in the rice cooker 2 during rice cooking, display of information indicating the operation state of the rice cooker, and an operation unit 14 for receiving a user command. The inner lid 4 is provided with a packing 15 that comes into close contact with the rice cooker 2 housed in the main body 1 when the lid 3 is closed.

  Inside the main body 1, a heater 10 as an example of a heating unit for heating and keeping warm the food to be heated, that is, the outer pot 10 that constitutes the container of the rice cooker 2 and the rice cooker 2. 11. A temperature sensor 12 for detecting the temperature of the rice cooker 2 is disposed. A control device 30 (see FIG. 2) that controls the operation of the rice cooker is disposed on the lid 3 or the main body 1.

  As shown in FIG. 1, the temperature sensor 12 is installed so that the bottom temperature of the rice cooker 2 can be measured, and the temperature sensor 12 measures the temperature of an object to be heated (rice, water) accommodated in the rice cooker 2. It has become so. In this embodiment, it is confirmed that the wall surface temperature of the bottom of the rice cooker 2 is substantially equal to the temperature of the heated object accommodated in the rice cooker 2.

  The operation unit 14 is integrally provided on the housing surface of the lid 3. It should be noted that the attachment position of the operation unit 14 is not limited to the present embodiment as long as the display information can be visually recognized by the user and the operation such as button operation can be performed.

  The rice cooker is connected to a commercial power source via a power cord (not shown). The power supplied from the commercial power source is supplied to each unit via a power source unit (not shown).

  The heater 11 as a heat source for heating and heat retention may be constituted by an IH (Induction Heating) heater in addition to a resistor heater such as a nichrome wire heater, and is particularly limited to these. is not.

  In addition, the determination means of the weight of the rice accommodated in the rice cooker 2 may be measured by, for example, a separately installed weight sensor, or may be applied to the load of the motor 21 (see FIG. 2) that rotates the stirring blade 8. May be detected based on the detection result of the sensor for detecting the water level in the rice cooker 2, or the user may input the amount of rice from the operation unit 14. Well, it is not particularly limited to these.

  The rice cooking course is selected and determined by the button operation of the operation unit 14 or the like. The control device 30 controls the heater 11 based on the signal from the temperature sensor 12 according to the control program corresponding to the selected rice cooking course, controls the overturning and standing of the stirring blade 9, and rotates the rotating body. Control with speed and drive time.

  FIG. 2 is a block diagram of the control device 30. As shown in FIG. 2, the control device 30 includes, for example, a microcomputer, and includes a heating control unit 31 that controls the heater 11 and a speed control unit 32 that controls the speed of the motor 21. The heating control unit 31 and the speed control unit 32 are configured by software.

  The heating control unit 31 follows the control program of the rice cooking course determined by the button operation of the operation unit 14 and the like so that the detected temperature of the temperature sensor 12 becomes the target temperature based on the output of the temperature sensor 12. The detected temperature is controlled so as to become the temperature shown in FIGS. 3A and 3B with time.

  The heating control unit 31 has drive input means 310. The drive input means 310 is configured by software. As shown in FIG. 4, the drive input means 310 increases the duty ratio as an example of the drive input value for driving the heater 11 at the initial low temperature of the rice cooking process, and then decreases the duty ratio.

  The rotational speeds of the motor 21 and, consequently, the rotating body 8 and the stirring blade 9 are detected by the rotational speed detection means 25, and the speed control unit 32 determines the motor 21 based on the output of the rotational speed detection means 25. The motor 21 is controlled so that the rotation speed becomes a predetermined rotation speed.

  The speed control unit 32 has drive input means 320. The drive input means 320 is configured by software. As shown in FIG. 4, the drive input unit 320 increases the duty ratio as an example of the drive input value for driving the motor 21 at the initial low temperature of the rice cooking process, and then decreases the duty ratio.

  The rice cooker having the above-described configuration operates as follows.

  Drawing 3A and 3B are figures explaining each process of rice cooking in this embodiment.

  In FIG. 3A, the vertical axis indicates the water temperature, and the horizontal axis indicates the elapsed time from the start of cooking. FIG. 3B shows the state of the stirring blade 9 and the operating state of the rotating body 8 in each step. The rice and water in the rice cooker 2 are controlled by the heating control unit 31 of the control device 30 to the temperatures shown in FIGS. 3A and 3B based on the output of the temperature sensor 12. 3A and 3B show a case where rice is cooked in a rice cooker with 5.5 go (1 go for rice is 150 grams) in a rice cooker 2 containing 3 go white rice.

  In this embodiment, the stirring blade 9 is developed (stands up) and rotated from the rotating body 8 together with the start of rice cooking, and the water and the rice contained in the rice cooker 2 are heated by the heater 12 while being stirred by the stirring blade 9. When the temperature sensor 12 reaches a temperature set within a temperature range of 50 to 66 ° C., the temperature of the temperature sensor 12 is set to the set temperature while stirring the water and rice stored in the rice cooker 2 in the same manner. A water absorption process for controlling heating by the heater 12 is performed so as to be held. Thereafter, the agitating blade 9 is housed (inverted) in the rotating body 8 and is heated by the heater 12 until the temperature sensor 12 reaches 95 ° C., and the rotating body 8 is rotated in a state where the agitating blade 9 is housed. The boiling process for continuing the heating by the heater 12 is performed. Finally, a steaming process is performed to complete the cooking.

  In the water absorption heating step and the water absorption step, the rice and water in the rice cooker 2 are stirred with the stirring blade 9 and heated with the heater 12 to gelatinize the starch of the rice. It is designed to allow sufficient water to be absorbed. By adding water and heat to rice, the raw starch changes its shape and becomes easily digestible alpha (α) starch. This change from raw starch to pregelatinized starch is called gelatinization. In addition to water and heat, starch is hydrolyzed by saccharifying enzymes to produce glucose as a sweet component.

  The optimum temperature of the saccharifying enzyme is about 60 ° C., and the gelatinization temperature is about 60 to 64 ° C. for glutinous rice and about 55 to 60 ° C. for glutinous rice.

  When gelatinization starts, when water and heat are added to the starch of rice, a phenomenon that changes to a paste is observed, and the surface of the rice grain gradually changes to a soft starch with a stickiness. Therefore, when rubbing is continued, a large amount of solid content such as glue is eluted, and if the amount of the eluted solid content is excessively large, charring occurs. In addition, yellowing after incubation is caused by the Maillard reaction between glucose and amino acids.

  Therefore, in order to avoid elution of excessive solid content and production of glucose, the temperature of the water absorption process is preferably 64 ° C. or lower.

  FIG. 4 shows the rotational speed (rpm) of the rotating body 8, that is, the stirring blade 9, and the output (W) of the heater 11 in the water absorption heating process and the water absorption process.

  As shown in FIG. 4, in the water absorption heating process, the heater 11 is driven by the drive input means 310 of the heating control unit 31 until the temperature of the rice in the rice cooker 2 reaches the first temperature (about 50 ° C.) from the normal temperature. The heating power is increased by setting the duty ratio of the input voltage to 100%, and the stirring power is increased by setting the duty ratio of the input voltage to the motor 21 to 80% by the drive input means 320 of the speed controller 32. That is, the output of the heater 11 is 1000 W, the operation of the heater 11 is continuous, the rotation speed of the stirring blade 9 is 150 rpm, and the ON / OFF time of the motor 21 is 12 seconds / 3 seconds.

  Thereafter, until the temperature of the rice in the rice cooker 2 reaches the second temperature (about 55 ° C.) from the first temperature (about 50 ° C.), input to the heater 11 by the drive input means 310 of the heating control unit 31. The duty ratio of the voltage is set to 53% and the heating power is weakened. The drive input means 320 of the speed control unit 32 reduces the stirring power by setting the duty ratio of the input voltage to the motor 21 to 60%. That is, the output of the heater 11 is 1000 W, the ON / OFF time of the heater 11 is 8 seconds / 7 seconds, the rotation speed of the stirring blade 9 is 150 rpm, and the ON / OFF time of the motor 21 is 9 seconds / 6 seconds. .

  Thereafter, the input voltage to the heater 11 by the drive input means 310 of the heating control unit 31 until the temperature of the rice in the rice cooker 2 reaches the set temperature (about 60 ° C.) from the second temperature (about 55 ° C.). The heating power is further reduced by setting the duty ratio to 33%, and the stirring power is reduced by setting the duty ratio of the input voltage to the motor 21 to 40% by the drive input means 320 of the speed control unit 32. That is, the output of the heater 11 is 1000 W, the ON / OFF time of the heater 11 is 5 seconds / 10 seconds, the rotation speed of the stirring blade 9 is 150 rpm, and the ON / OFF time of the motor 21 is 6 seconds / 9 seconds. .

  Here, the first temperature (about 50 ° C.) is a temperature at which the amount of eluted solids increases. A test apparatus for determining this temperature is shown in FIG. 5A. As shown in FIG. 5A, in this test apparatus, a rice cooker 102 is arranged inside a heat insulating box 116, and a halogen heater 117 is arranged around the rice cooker 102. A shaft 119 having a propeller blade 118 having a diameter of 50 mm fixed at the tip passes through the center of the heat insulating lid 120 and is connected to the motor 121. A thermocouple 122 for measuring the temperature inside the rice cooker 102 is installed via a heat insulating lid 120.

  And using the said test apparatus, 450 g of rice and 665 mL of water are first put in the inside of the rice cooker 102, the motor 121 is driven, the propeller blade 118 is rotated at 750 rpm, and the operation rate (duty ratio) is 80% ( The input of the halogen heater 117 is controlled and stored so that the temperature inside the rice cooker 102 reaches about 60 ° C. in about 20 minutes while rotating at an ON time of 8 seconds and an OFF time of 2 seconds. Subsequently, after the rice cooker 102 was cooled, rice and water were similarly added, and after 2.5 minutes from the start, the rice and water in the rice cooker 102 were separated, and the water was completely dried. The remaining solid content was measured. Further, the solid content after 5 minutes, 10 minutes, 15 minutes and 20 minutes was measured by the same method.

  The measurement result is shown in FIG. 5B. As shown in FIG. 5B, when the temperature inside the rice cooker 102 is from room temperature to about 50 ° C., there is no significant difference in the eluted solid content. On the other hand, when it exceeds 50 degreeC, the elution solid content will increase rapidly. That is, this 50 ° C. can be said to be a critical temperature.

  According to the rice cooker having the above configuration, in the water absorption heating process in which the rice and water are heated from normal temperature to a set temperature (about 60 ° C.) by the drive input means 320 of the speed control unit 32, the normal temperature is changed to the first temperature. A drive input value (duty ratio) for driving the motor 21 while raising the temperature to (about 50 ° C.) is used to drive the motor 21 while raising the temperature from the first temperature to the set temperature. Make it larger than the drive input value (duty ratio).

  In this way, by increasing the stirring until the temperature of the rice and water reaches the first temperature, the temperature can be quickly raised, water absorption into the rice can be promoted, and uneven rice cooking can be suppressed. On the other hand, after the temperature of the rice and water reaches the first temperature, the amount of solids eluted from the rice is reduced by weakening the agitation, and there are problems such as stickiness and scorching in the finished rice after cooking. Occurrence can be prevented.

  In addition, the drive input means (duty ratio) for driving the heater 11 during the temperature rise from the normal temperature to the first temperature in the water absorption heating process by the drive input means 310 of the heating control unit 31. The driving input value (duty ratio) for driving the heater 11 during the temperature rise from the first temperature to the set temperature is set larger.

  Thus, the temperature of rice and water can be raised more rapidly by increasing the heating power until the temperature of rice and water reaches the first temperature. On the other hand, after the temperature of rice and water reaches the first temperature, overshooting of the temperature of rice and water can be prevented by reducing the heating power.

  In addition, since the first temperature is a temperature at which the amount of the eluted solid content increases, the amount of the eluted solid content from the rice can be further reliably reduced by reducing the stirring after reaching the increased temperature of the eluted solid content. .

  In the above embodiment, the duty ratio is described as an example of the drive input value. However, the drive input value may be a voltage value or a current value.

  As shown in FIG. 6, the rotational speed of the motor 21 (stirring blade 9) is raised from the first temperature to the set temperature (about 60 ° C.) while the temperature is raised from the normal temperature to the first temperature (about 50 ° C.). You may make it make it larger than the rotation speed of the motor 21 in the meantime. That is, the number of revolutions is set to 150 rpm from room temperature to 50 ° C., 100 rpm from 50 ° C. to 55 ° C., and 50 rpm from 55 ° C. to 60 ° C.

  Further, the output of the heater 11 during the temperature rise from the normal temperature to the first temperature may be made larger than the output of the heater 11 during the temperature rise from the first temperature to the set temperature. That is, the output is 1000 W at room temperature to 50 ° C., 700 W at 50 ° C. to 55 ° C., and 300 W at 55 ° C. to 60 ° C.

  In the above embodiment, the second temperature (55 ° C.) is provided between the first temperature (50 ° C.) and the set temperature (60 ° C.), and the drive input value is gradually reduced. The drive input value from the normal temperature to the first temperature may be larger than the drive input value from the first temperature to the set temperature.

  In the above embodiment, the drive input unit 310 is provided in the heating control unit 31, but the drive input unit 310 may be omitted.

  Although the rice cooker as an example of the heating cooker has been described in the above embodiment, the heating cooker may be a range or an oven. Any cooking device may be used as long as it can cook rice.

DESCRIPTION OF SYMBOLS 1 Main body 2 Rice cooker 3 Lid 4 Inner lid 8 Rotating body 9 Stirring blade 10 Inner pan 11 Heater (heating part)
DESCRIPTION OF SYMBOLS 12 Temperature sensor 21 Motor 25 Rotational speed detection means 30 Control apparatus 31 Heating control part 310 Drive input means 32 Speed control part 320 Drive input means

Claims (3)

A rice cooker for storing a heated object including rice and water;
A stirring mechanism for stirring the object to be heated in the rice cooker;
A motor for driving the stirring mechanism to stir the object to be heated;
A heating unit for heating the rice cooker;
A temperature sensor for detecting the temperature of the object to be heated;
A heating control unit that controls the heating unit based on the output of the temperature sensor so that the temperature of the object to be heated becomes a predetermined temperature;
A rotational speed detecting means for detecting the rotational speed of the motor;
A speed control unit that controls the motor based on the output of the rotational speed detection means so that the rotational speed of the motor becomes a predetermined rotational speed;
The speed controller is
In the water absorption heating step of heating the object to be heated from room temperature to a set temperature, a drive input value for driving the motor while raising the temperature from room temperature to the first temperature is set from the first temperature to the set temperature. A heating cooker characterized by comprising drive input means for making the value larger than the drive input value for driving the motor while the temperature is raised to The heating cooker according to claim 1, wherein
The heating control unit
In the water absorption heating step, a driving input value for driving the heating unit while the temperature is raised from normal temperature to the first temperature is driven, and the heating unit is driven while the temperature is raised from the first temperature to the set temperature. A heating cooker comprising drive input means for making the value larger than the drive input value for performing the operation. The heating cooker according to claim 1 or 2,
The cooking device according to claim 1, wherein the first temperature is a temperature at which the amount of eluted solids increases.

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