JP6030286B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker, and more particularly to a rice cooker that can be applied even when a non-metallic inner pot such as ceramics is used.

  In recent years, rice cookers have a microcomputer to control the energization current to the IH coil and heater, which are heating means, based on the temperature of the inner pot detected by a temperature sensor arranged around the inner pot, By finely adjusting the temperature of the inner pot in each of the rice cooking processes, ie, the temperature process, the boiling process, and the steaming process, delicious rice can be cooked regardless of changes in the amount of cooked rice and the environmental temperature.

  An example of the set temperature of the inner pot in the rice cooking process is shown in FIG.

  As shown in FIG. 9, in the first water absorption step of the rice cooking step, the temperature of the inner pot rises from the room temperature shown as 20 ° C. in the example of FIG. After reaching the set temperature in the water absorption step, the rice is allowed to absorb water while maintaining the set temperature in this water absorption step for a certain time (as an example, 10 to 15 minutes).

  After the water absorption step for a predetermined time, a boiling step for maintaining the temperature of the inner pot at the temperature at which the water is boiled is provided through a temperature increasing step for raising the temperature of the inner pot to around 100 ° C. at which water boils all at once. By this boiling process, α-starching of rice proceeds, and the rice has stickiness and umami.

  At the end of the boiling process, the water in the inner pot disappears and the temperature of the inner pot becomes equal to or higher than the boiling temperature of the water, the excess water adhering to the surface of the rice is removed, the rice cooking process by the steaming process Is completed. Normally, the cooked rice is kept warm by the jar function that the rice cooker also has.

  The water absorption process in the rice cooking process is a process in which the rice absorbs moisture at a relatively low temperature, and the water absorption rate in the water absorption process greatly affects the hardness of the cooked rice, so it is important to control the water absorption rate Become. Also, if too much water is absorbed in the water absorption process, the amount of water in the inner pot required in the subsequent heating process and boiling process becomes too small, making it difficult to cook uniformly. Problem arises.

  In such a water absorption process, in order to control the temperature of the inner pot and realize preferable water absorption conditions, the temperature of the water absorption process should be 60 ° C. or more and 1 minute or more and 30 minutes or less, or the water absorption process temperature may be It has been proposed that the temperature be set in two stages of 40 ° C. and 60 ° C. or higher and lower than 70 ° C. (see Patent Document 1).

  In order to control the water absorption rate of rice and adjust the hardness of the cooked rice to the user's preference such as “soft” “normal” “hard” When the temperature of the water reaches 70 ° C. or higher, a technique is proposed in which heating by the heater is temporarily stopped to secure time for water absorption, and then the heater is energized again to raise the water to the boiling temperature (patent) Reference 2).

JP 2001-046224 A Japanese Patent Laid-Open No. 08-033567

  In the rice cooking process, if temperature control is performed to turn off the heater in order to prevent spilling in the boiling process, the temperature of the inner pot will drop and the progress of alpha starching, which is the umami component of rice There is a problem that will decrease. For this reason, in order to be able to draw out the flavor of rice while preventing spilling in the boiling process, an inner pot made of non-metallic material such as ceramics with high heat storage characteristics (not so-called metal) Earthenware pots are used.

  However, as the reverse of the high heat storage, the non-metallic material inner pot has low thermal conductivity, so in the water absorption process that is the start of the rice cooking process, The temperature does not rise. In addition, in an inner pan using a non-metallic member, an eddy current cannot be directly generated by an IH coil, so the coating of a metal film or a metal foil is transferred. It is difficult to raise the temperature of the entire inner pan evenly. For this reason, when controlling the input current to the heating means so as to achieve the set temperature (50 ° C.) shown in FIG. 9, for example, as the water absorption process in the rice cooker using the above-mentioned conventional metal inner pot There was a problem that cooking unevenness occurred without heat spreading over the entire inner pot.

  In addition, because of the low thermal conductivity of the inner pot, even if the current of the heating means is turned off immediately after the temperature sensor detects that the inner pot temperature has reached the predetermined set temperature, the temperature of the inner pot for a while. It has been impossible to avoid the occurrence of a large overshoot in which the temperature continues to rise and reaches an undesired high temperature. When the temperature of the inner pot becomes too high in the water absorption process, the water absorption rate of the rice in that portion protrudes too high, and there is a problem that the gelatinization of the surface of a portion of the rice proceeds too much.

  On the other hand, even in the case of a metal inner pot, it is impossible to uniformly arrange IH coils and heaters that are heating means for supplying heat to the inner pot so as to surround the entire circumference of the inner pot. The temperature difference between the part facing the heating means and the part where the heating means is not arranged in close proximity is not small, especially in the case of a small amount of rice cooking. Due to the temperature distribution, there was a problem that the uniformity of the cooked rice could not be obtained sufficiently. Also, as with non-metallic inner pots, if a large overshoot occurs in the water absorption process where the temperature of the inner pot rises too much relative to the set temperature, partial gelatinization of the rice progresses and causes uneven cooking. There was also a problem of becoming.

  The present invention solves such a problem of the prior art, and obtains a rice cooker that can realize a rice cooking process that suppresses uneven cooking by raising the temperature of the inner pot in the water absorption process in a uniform state as much as possible. For the purpose.

Moreover, in order to solve the said subject, the rice cooker of this invention heats the said rice cooker main body which has the inner pot which puts a to-be-cooked rice, the inner pot accommodating part which accommodates the said inner pot so that extraction is possible, and the said inner pot. Heating means, a temperature sensor for detecting the temperature of the inner pot, a heating control means for controlling the heating means so that the temperature of the inner pot detected by the temperature sensor becomes a predetermined set temperature, and ventilation Provided on the bottom surface of the inner pot accommodating part or the lower part of the side wall part, which can blow out the air from the fan and the blower fan without passing through the arrangement position of the heating means in the path between the blower fan A blower fan, and a blower fan control unit that controls the operation of the blower fan, wherein a plurality of the blower openings are arranged on a circumference centering on the center of the inner pot accommodating part, and the blower fan control The temperature of the inner pot is 50 By operating the blower fan in the following water absorption step, characterized in that feeding the air from the blower fan between the inner pot and the inner pot accommodating portion from the blower opening.

  In the first rice cooker of the present invention, in the water absorption process in which the temperature of the inner pot is 50 ° C. or less, the heating control means has the heating means so that the temperature of the inner pot rises through a plurality of temperature rising stages that gradually increase. Control. For this reason, the temperature of the whole inner pot can be raised gently, and the rice cooker which can implement | achieve the rice cooking process which suppressed cooking unevenness can be obtained.

  Further, in the second rice cooker of the present invention, the blower fan control unit operates the blower fan in the water absorption process, and the inner pot accommodating portion and the inner portion from the blower opening provided on the bottom surface of the inner pot accommodating portion or the lower side wall portion. Air is sent to and from the pan. For this reason, the temperature of the whole inner pot can be raised, equalizing the temperature of an inner pot, and the rice cooker which can implement | achieve the rice cooking process which suppressed cooking unevenness can be obtained.

It is a perspective view which shows the external appearance of the rice cooker concerning embodiment of this invention. It is sectional drawing which shows the structure of the rice cooker concerning embodiment of this invention. It is an image figure explaining the flow of the airflow by the ventilation fan of the rice cooker concerning embodiment of this invention. It is a figure explaining the temperature control of the inner pot in the water absorption process in the rice cooker concerning embodiment of this invention. It is a figure which shows the temperature change of the inner pot in the water absorption process in the rice cooker concerning embodiment of this invention, and the rice in an inner pot. It is a figure which shows the temperature change of the inner pot in the water absorption process in the rice cooker of a comparative example, and the rice in an inner pot. It is a figure which shows the temperature change of the inner pot in the water absorption process in another Example, and the rice in an inner pot in order to show the effect by the ventilation fan of the rice cooker concerning embodiment of this invention. It is a side view which shows the structure of the inner pot in the modification of the rice cooker concerning embodiment of this invention. It is a figure which shows the temperature control of the whole rice cooking process in the conventional rice cooker.

  The first rice cooker of the present invention includes an inner pot in which to-be-cooked rice is placed, a rice cooker body having an inner pot accommodating portion that accommodates the inner pot in a removable manner, heating means for heating the inner pot, A temperature sensor for detecting the temperature of the inner pot; and heating control means for controlling the heating means so that the temperature of the inner pot detected by the temperature sensor becomes a predetermined temperature. In the water absorption process at 50 ° C. or lower, the heating control means controls the heating means so as to increase through a plurality of temperature raising steps in which the temperature of the inner pot gradually increases.

  The 1st rice cooker of this invention can raise the temperature of an inner pot by a gentle step in the water absorption process in which the temperature of the inner pot at the time of a rice cooking start is 50 degrees C or less by providing the said structure. For this reason, even when using an inner pan made of a non-metallic material with low thermal conductivity, the heat from the heating means can be adequately distributed throughout the inner pan, and the temperature distribution of the inner pan can be made uniform and cooked. Unevenness can be suppressed. At the same time, since it is possible to suppress the occurrence of large overshoots where the temperature of the inner pot becomes a high temperature far from the set temperature, it is effective that the gelatinization of only a part of the rice in the inner pot proceeds. Can be prevented. Moreover, even in the metal inner pot, the unevenness of the inner pot temperature between the part facing the heating means and the part far from the heating means can be eliminated, and the occurrence of uneven cooking can be suppressed. .

  The 1st rice cooker concerning the said invention WHEREIN: It is preferable that the number of steps of the temperature rising stage of the temperature of the said inner pot in the water absorption process whose temperature of the said inner pot is 50 degrees C or less is 5 or more. By doing in this way, the temperature rise of the inner pot in a water absorption process can be controlled more exactly.

  Further, in the water absorption process in which the temperature of the inner pot is 50 ° C. or less, the heating control means may repeat turning on / off the heating means a number of times according to the number of stages of the temperature increase of the inner pot. preferable. By doing in this way, generation | occurrence | production of a big overshoot can be suppressed and the temperature of an inner pot can be raised gently.

  Moreover, the 2nd rice cooker of this invention is a rice cooker main body which has the inner pot which puts a to-be-cooked rice, the inner pot accommodating part which accommodates the said inner pot so that extraction is possible, The heating means which heats the said inner pot, A temperature sensor for detecting the temperature of the inner pot, a heating control means for controlling the heating means so that the temperature of the inner pot set by the temperature sensor becomes a predetermined temperature, a blower fan, and the inner fan A blower opening provided at the bottom of the pot accommodating portion or the lower portion of the side wall, and a blower fan controller that controls the operation of the blower fan, wherein the blower fan controller operates the blower fan in the water absorption step. The air is sent between the inner pot accommodating portion and the inner pot from the blower opening.

  By setting it as such a structure, the 2nd rice cooker of this invention will produce the airflow which goes to the upper part from the lower part of an inner pot around an inner pot in a water absorption process, The heat | fever from a heating means, In addition to heat conduction by the inner pot itself, it can be spread throughout the air by the air flow generated around the inner pot. For this reason, even when an inner pot made of a non-metallic material with low thermal conductivity is used, the temperature distribution of the inner pot can be made uniform and uneven cooking can be suppressed. At the same time, since it is possible to suppress the occurrence of a large overshoot, it is possible to effectively prevent the gelatinization of only a part of the rice in the inner pot from proceeding. Moreover, even in the metal inner pot, the unevenness of the inner pot temperature between the part facing the heating means and the part far from the heating means can be eliminated, and the occurrence of uneven cooking can be suppressed. .

  In the second rice cooker, in the water absorption process in which the temperature of the inner pot is 50 ° C. or less, the heating control unit is configured to increase the temperature through a plurality of temperature rising stages in which the temperature of the inner pot gradually increases. It is preferable to control the means. By doing in this way, the temperature of the whole inner pot can be raised gently, aiming at equalization, and generation | occurrence | production of cooking unevenness can be suppressed more effectively.

  Moreover, it is desirable that the number of steps of the temperature rise of the inner pot in the water absorption process in which the temperature of the inner pot is 50 ° C. or less is 5 or more, and in the water absorption process in which the temperature of the inner pot is 50 ° C. or less, It is preferable that the heating control unit repeats on / off of the heating unit a number of times according to the number of steps of the temperature raising stage of the temperature of the inner pot. By doing in this way, it can raise gently, controlling the temperature of an inner pot more reliably.

  Furthermore, the inner pot is preferably made of a non-metallic material. By doing in this way, while using the heat storage property in the boiling process of the non-metallic inner pot, the entire cooked rice can be absorbed by water, and a rice cooker that can cook rice more deliciously is obtained. be able to.

  Note that the rice cooker of the present invention includes an inner pot in which to-be-cooked rice is placed, a rice cooker body having an inner pot accommodating portion that accommodates the inner pot in a removable manner, a heating means for heating the inner pot, A temperature sensor for detecting the temperature of the pot; and a heating control means for controlling the heating means so that the temperature of the inner pot detected by the temperature sensor becomes a predetermined set temperature, and the temperature of the inner pot is 50 In the water absorption step of less than or equal to ° C., it is preferable that the set temperature is set so as to increase through a plurality of temperature rising steps that gradually increase.

  By doing in this way, the temperature control which raises gently the temperature of the whole inner pot, aiming at equalization can be performed.

  Hereinafter, as an embodiment of the rice cooker according to the present invention, an inner pot is a non-metallic earthen pot pot, and a rice cooker provided with a blower fan capable of sending air into the gap between the inner pot and the inner pot accommodating portion. An example will be described.

  FIG. 1 is a perspective view showing the appearance of the rice cooker of the present embodiment. Moreover, FIG. 2 is a figure which shows the cross-sectional structure of the rice cooker of this embodiment.

  As shown in FIG. 1 and FIG. 2, the rice cooker 100 according to the present embodiment includes an inner pot 30 for storing rice and water, and in addition, a cooked rice mode and the like, and a cooked rice that is various ingredients such as vegetables and beans, It has the rice cooker main body 20 which can accommodate this inner pot 30 in the inner pot accommodating part 20a.

  FIG. 1 shows a state in which the lid 10 attached to the rice cooker body 20 so as to be opened and closed is closed.

  The lid 10 is provided with a switch 11 for a user to give various settings to the rice cooker 100, and a liquid crystal display unit 12 for displaying an operation state by the switch 11, an operation state of the rice cooker 100, and the like. The switch 11 includes a rice cooking switch, a heat retention switch, a menu switch for setting various menus, a timer switch for setting time, and the like.

  Further, the lid body 10 is provided with a pressure regulating cap 13, and the ball-shaped check valve 14 (see FIG. 2) inside the pressure regulating cap 13 is operated so that the valve pressure of the check valve 14 is closed. The steam is discharged to the outside of the lid body 10 only when it exceeds the limit, and the gas-liquid-separated “needle” is temporarily stored and then returned to the inner pot 30.

  A lock button 21 is provided on the front side surface of the rice cooker body 20, and when the lock button 21 is pushed in with the lid 10 closed, the lid 10 is unlocked, and a lid is formed by a spring mechanism (not shown). 10 is opened to the rear (back) side in FIG.

  In addition, a handle 22 that allows the entire rice cooker 100 to be carried is provided behind the rice cooker body 20.

  As shown in FIG. 2, operation circuits of various switches 11, not shown in FIG. 2, and a display image on the liquid crystal display unit 12 are output to a portion located below the liquid crystal display unit 12 inside the lid 10. A circuit unit 15 including a liquid crystal unit driving circuit and the like is provided. Moreover, in the rice cooker 100 of this embodiment, the microcomputer which is not shown in which the control circuit which controls a rice cooking program was mounted is also mounted on the circuit board which comprises the circuit part 15. FIG. In the rice cooker 100 of the present embodiment, the control circuit included in the microcomputer disposed in the circuit unit 15 has heating control means for controlling energization to the heating means 25 (25a, 25b, 25c), and a blower fan 23 described later. A blower fan control unit for controlling the operation is also included.

  In addition, in the rice cooker 100 of this embodiment, it is only an example that the microcomputer by which the control circuit containing a heating control means and a ventilation fan control part is mounted is arrange | positioned in the lower part of the liquid crystal display part 12. FIG. The heating control unit and the blower fan control unit may be mounted on separate circuit boards, respectively, and the heating control unit and the blower fan control unit are separated from the liquid crystal display unit 12 in the lid 10. For example, it may be arranged in the rice cooker body 20.

  In the rice cooker 100 of this embodiment, the lid sensor 16 which is one of the temperature sensors for detecting the temperature of the inner pot 30 is positioned above when the inner pot 30 is stored in the inner pot accommodating portion 20a. It arrange | positions at the back surface of the cover body 10 so that the temperature of the vapor | steam above the inner pot 30 at the time of rice cooking can be measured. Each temperature sensor used in the rice cooker 100 of the present embodiment, such as the lid sensor 16 and the center sensor 26 described later, is a conventionally known temperature sensor configured using a thermal electric element typified by a thermistor, for example. Can be used as is.

  The lid 10 can be opened and closed by a hinge mechanism 27 of the rice cooker body 20. And when the cover body 10 is closed, the cover body 10 is fixed in the state pressed firmly on the upper surface of the rice cooker main body 20 by the lock mechanism not explicitly shown in FIG. The lid 10 and the rice cooker body 20 are firmly pressed and fixed, so that the seal packing (not shown) of the lid 10 is pressed against the lip of the inner pot accommodating portion 20a of the rice cooker body 20 from above. It will be in the state which seals the space of the inner pot accommodating part 20a which accommodated the inner pot 30, and performs rice cooking or heat insulation.

  A pair of blower fans 23 are arranged inside the rice cooker body 20 of the rice cooker 100 of the present embodiment. The blower fan 23 rotates (ON), stops (OFF), and rotates forward and reverse as necessary according to a signal from a blower fan control unit inside the microcomputer mounted on the circuit board 15 of the lid 10. Operation is controlled.

  In the rice cooker 100 of this embodiment, the two blower fans 23 are arrange | positioned at the left and right of the back side at the time of seeing the rice cooker 100 from the lock button 21 side which is a front side. In FIG. 2, only one of the two blower fans 23 on the near side in FIG. 2 is shown. The blower fan 23 blows out air sucked from a suction port (not shown) from a blower port 24 provided on the lower side of the side wall portion of the inner pot accommodating portion 20a to a gap portion with the inner pot 30 in the inner pot accommodating portion 20a. In the rice cooker 100 of this embodiment, the ventilation opening 24 is provided with a total of six ventilation openings 24 at intervals of 60 degrees with respect to the center of the inner pot accommodating part 20a.

  Around the inner pot accommodating portion 20a of the rice cooker body 20, a first work coil 25a, a second work coil 25b, and a heater 25c are provided as the heating means 25.

  The first work coil 25a faces the bottom surface of the inner pot 30 and is disposed on the bottom surface of the inner pot accommodating portion 20a. Since the center sensor 26 which is a temperature sensor for detecting the temperature of the bottom surface of the inner pot 30 is disposed in the center of the bottom surface of the inner pot accommodating portion 20a, the first work coil 25a has a hole in the center in plan view. It has an open ring shape.

  The second work coil 25b is disposed so as to face the inclined portion located at the boundary between the bottom surface and the side surface of the inner pot 30. Similarly to the first work coil 25a, the second work coil 25b has an annular shape.

  In the inner pot 30 of the rice cooker 100 of the present embodiment, stainless steel is formed on the inner surface side of the non-metallic inner pot body so that an eddy current is generated by the current flowing through the first work coil 25a and the second work coil 25b. Alternatively, a metal thin film such as silver is formed by transferring a coating or a metal foil. Then, when a current flows through the first work coil 25a and the second work coil 25b, the metal thin film generates heat, and this heat generation increases the temperature of the entire pot.

  A side heater 25 c is disposed on the side wall of the inner pot accommodating portion 20 a facing the side surface of the inner pot 30. When the current flows through the side heater 25c, heat is generated and the inner pot 30 is kept warm during the jar function after rice cooking, and the inner pot 30 is also used with the first work coil 25a and the second work coil 25b during rice cooking. Can be heated.

  In the rice cooker 100 of the present embodiment, the first work coil 25a, the second work coil 25b, and the side heater 25c constitute the heating means 25, and are mounted on the microcomputer of the circuit unit 15 of the lid 10. By controlling the amount of current flowing through each of the heating control means, the heating means is turned on and off, and the amount of heat generated when the heating means is on is controlled. In addition to the first work coil 25a, the second work coil 25b, and the side heater 25c, as the heating means 25, a coil is formed in another part around the inner pot accommodating portion 20a and in the lid body 10. It is possible to arrange a heater or the like.

  The hinge mechanism 27 is provided in the upper part in the back surface of the rice cooker main body 20, and it can open and close from the state which the cover body 10 covered the inner pot accommodating part 20a.

  In order to supply electric power to the rice cooker 100, a cord reel that houses a power cord connected to a power plug 28 connected to a commercial power source is disposed below the hinge mechanism 27.

  In addition, as a whole shape of the rice cooker 100 of this embodiment, and a concrete structure and arrangement | positioning of each part, various structures different from the structure illustrated to the said FIG. 1 and FIG. 2 are employable.

  Here, the flow of air in the gap portion between the inner pot accommodating portion 20a and the inner pot 30 when the blower fan 23 is operated will be described with reference to FIG.

  As shown in FIG. 3, the air sent from the blower opening 24 provided in the lower side of the side wall part of the inner pot accommodating part 20a of the rice cooker main body 20 is air current by operating the blower fan 23 not shown in FIG. 29 is formed. For example, as shown in FIG. 3, the airflow 29 is directed in the direction of the upper left rather than directly above, so that the airflow 29 circulates clockwise in the gap portion between the side wall of the inner pot accommodating portion 20 a and the inner pot 30. You can make a flow of air.

  In the rice cooker 100 of this embodiment, the 1st work coil 25a which is the heating means 25 is arrange | positioned on the bottom face of the inner pot accommodating part 20a facing the bottom face of the inner pot 30, and 2nd workpiece | work. Since the coil 25b is also provided facing the boundary between the bottom surface and the side surface of the inner pot 30, the temperature of the lower portion of the inner pot 30 is increased by the first work coil 25a and the second work coil 25b. It's easy to do. Moreover, since the side heater 25c is also arranged opposite to the central portion in the vertical direction of the side surface of the inner pot 30, the temperature of the inner pot 30 itself and the temperature of the air around the inner pot 30 are the same as those of the inner pot 30. The lower part tends to be higher than the upper part. On the other hand, the brim part formed in the upper end of the inner pot 30 is covered with the lid 10 and the rice cooker body 20 so that the spilled food to be cooked heated during rice cooking does not occur. It is difficult to heat the part directly with heating means, and the temperature on the upper side of the inner pot 30 is less likely to be higher than other parts.

  For this reason, in the rice cooker 100 of this embodiment, by providing the blower opening 24 on the lower side of the side wall portion of the inner pot accommodating portion 20a, the air flow 29 blown out from the blower opening 24 is used as a whole on the outer surface of the inner pot 30. By moving from the bottom to the top, the high temperature air located around the lower part of the inner pot 30 is directed toward the collar part above the inner pot 30 and the vicinity thereof, thereby raising the overall temperature of the inner pot 30. It can be made to.

  In addition, in the rice cooker 100 of this embodiment, the two air blowing fans 23 provided in the left and right rear when the rice cooker 100 is viewed from the front are alternately operated every 30 seconds to alternately generate airflows in opposite directions. It is generated in the gap between the inner pot accommodating portion 20a and the inner pot 30. However, in the rice cooker according to the present invention, the number of blower fans, the method of controlling the operation thereof, the number of blower ports, and the arrangement positions thereof are not limited to those illustrated. One or three or more blower fans can be provided, and instead of operating a plurality of blower fans alternately, a plurality of blower fans can be operated simultaneously to generate a stronger airflow. Moreover, the ventilation port 24 can also be provided in the bottom face of the inner pot accommodating part 20a not only in the side wall part lower side of the inner pot accommodating part 20a. However, as described above, since the temperature on the lower side of the inner pot 30 becomes higher due to the arrangement position of the heating means 25, the air flow generated by the blower fan 23 is more preferably directed from the bottom to the upper. It is further preferable to generate an air flow surrounding the periphery of the inner ring 30 in order to uniformly raise the temperature of the entire inner pot 30.

  Drawing 4 is a figure for explaining temperature control of inner pot 30 in a water absorption process of rice cooker 100 concerning this embodiment.

  The temperature of the inner pot 30 in the water absorption process of the rice cooker 100 according to the present embodiment is from the initial set temperature at the start of the water absorption process to the set temperature of the inner pot at the start of the temperature raising process performed following the water absorption process. The temperature is set so as to rise through a plurality of temperature rising stages that gradually rise.

  Specifically, as shown in FIG. 4, the water absorption process is started, that is, the set temperature 41 at the time t = 0 at the start of the rice cooking program is set to, for example, 30 ° C. higher than room temperature, and the water absorption process is performed. When the set temperature at the time t = 12, which is the start of the subsequent heating process, is 40 ° C., the water absorption process is divided into 12 stages, and the set temperature 41 during this period is a predetermined time (for example, 1 minute) While maintaining a constant temperature, it is set to gradually increase in a stepped manner. In the example shown in FIG. 4, the set temperature rise corresponding to one step of the staircase is 0.8 ° C. as an example, and the set temperature in the water absorption process is 30 ° C. in the water absorption process for 12 minutes. From the temperature at the time of the water absorption process disclosure to the temperature at the end of the water absorption process at 40 ° C., the temperature is set to rise through 12 stages of temperature increase.

  The heating control means 25 is configured so that the detection temperature of various sensors including the center sensor 26 that detects the temperature of the center outside the bottom of the inner pot 30 follows the set temperature 41 shown in FIG. To control. Specifically, the heating means 25 as a whole is turned on and off, and the current amount when the heating means 25 is turned on, and the three heating means 25 of the first work coil 25a, the second work coil 25b, and the side heater 25c are adjusted. Control which one of the heating means 25 is turned on with which current amount is performed. In FIG. 4, the time when the heating means 25 is turned on is represented as shaded 44. When the heating means 25 is turned on, the temperature 42 of the center sensor 26 shown in FIG. 4 starts to rise as the temperature of the inner pot 30, and when the temperature 42 of the center sensor 26 reaches the set temperature 41, the heating control means is heated. The means 25 is turned off.

  The heating control means turns on the heating means again when the set temperature 41 changes to a slightly higher temperature which is the next stage. Then, when the temperature 42 of the center sensor 26 indicating the temperature of the inner pot 30 rises again and becomes higher than the set temperature 41, the heating control means turns off the heating means again. When the heating control means repeats such control, the temperature of the inner pot 30 that appears as the temperature 42 of the center sensor 26 rises while repeating raising and lowering with respect to the set temperature 41 as shown in FIG.

  In the rice cooker 100 of the present embodiment, the set temperature 41 in the water absorption process is gradually increased from the initial set temperature at the start of the water absorption process to the set temperature of the inner pot at the start of the temperature rising process performed subsequent to the water absorption process. By setting so as to increase through a plurality of temperature raising steps, the temperature 42 of the center sensor 26 that is the temperature of the inner pot 30 can be gradually increased as shown in FIG. For this reason, the temperature of the entire inner pot 30 can be reliably increased despite the use of an earthen pot made of a non-metallic material with low thermal conductivity as the inner pot 30, which is shown as a dotted line 43 in FIG. The temperature of the cooked rice housed in the inner pot 30 can be raised gently.

  As shown in FIG. 4, the temperature 42 of the center sensor 26 indicating the temperature of the inner pot 30 in the water absorption process of the rice cooker 100 of the present embodiment has an overshoot that exceeds the set temperature 41 when viewed microscopically. Has occurred. However, since the set temperature 41 is set so as to go through a plurality of temperature rising stages in which the temperature gradually rises, the current is supplied to the heating means 25 by the heating control means and the set temperature 41 at the start of each temperature rising stage and the actual temperature. Since the temperature difference with the temperature 42 of the center sensor 26 which is the temperature of the inner pot 30 is small, the amount of current passed to the heating means 25 by the heating control means becomes relatively small, and the size of the inevitable overshoot is reduced. Can be small. For this reason, the temperature 42 of the center sensor 26 which is the temperature of the inner pot 30 and the temperature 43 of the cooked rice in the inner pot 30 are set to 40 ° C. which is a set temperature at the start of the temperature raising process. It can be controlled to an equivalent temperature or a temperature below the equivalent. Therefore, like the temperature control in the water absorption process in the conventional rice cooker, the temperature from 40 ° C to around 60 ° C is centrally set as the set temperature in the water absorption process, and the temperature of the non-metallic inner pot is this setting It is possible to suppress the occurrence of a large overshoot that has occurred when the heating control means controls the heating means so as to follow the temperature as soon as possible. As a result, it is possible to effectively avoid that the temperature of a part of the inner pot 30 becomes extremely high and the gelatinization of only that part of the rice proceeds. In the rice cooker 100 of the present embodiment, , You can cook the whole rice and cook it without any unevenness.

  FIG. 5 shows the temperature change of the cooked rice in the inner pot 30 and the inner pot 30 in the water absorption process when cooking with the rice cooker 100 according to the present embodiment.

  In FIG. 5, the solid line 51 is the temperature measured by placing the thermocouple at the center of the bottom of the inner pot 30 inside the temperature of the inner pot 30. Thus, since it is the temperature inside the inner pot 30, the temperature shown by the solid line 51 is different from the temperature detected by the center sensor 26. Moreover, the dotted line 52 is the temperature of the rice located in the upper part of the inner pot 30 among the white rice accommodated in the inner pot 30, the alternate long and short dash line 53 is the temperature of the rice in the central portion of the inner pot 30, and the two-dotted line 54 is the inner pot. The temperature of the rice located in the lower part of 30 is shown, respectively.

  In the measurement of the temperature change in FIG. 5, assuming that rice is cooked with 5.5 rice of white rice, the initial set temperature of the inner pot at the start of the water absorption process is 25 ° C., that is, the temperature increase process is started. The set temperature of the inner pot at the time was 40 ° C. Moreover, the length of the whole water absorption process was made into 15 minutes, and set temperature was set so that it might go up through 15 temperature rising steps in this 15 minutes. The blower fan 23 was operated alternately every 30 seconds from the start of the water absorption process to the end of the water absorption process using two fans. Furthermore, after the water absorption process, the rice cooking was completed through a temperature raising process, a boiling process, and a steaming process based on a set temperature determined according to a normal rice cooking program. The blower fan 23 was operated from the latter half of the temperature raising process to the beginning of the steaming process.

  As shown in FIG. 5, in the rice cooking by the rice cooker 100 of this embodiment, in the water absorption process, the upper part in the inner pot 30 shown by the dotted line 52, the center part in the inner pot 30 shown by the one-dot chain line 53, the two-dot chain line 54 The temperature of the rice located in the lower part of the inner pot 30 shown in FIG. 2 rises almost evenly without a large temperature difference, and at the end of the water absorption process, the rice in any part is also the set temperature of the inner pot 30 It can be seen that the temperature has reached 40 ° C.

  On the other hand, as a comparative example, when the set temperature of the water absorption process is not set so as to increase through the 15th temperature increase step, it is centrally set to 40 ° C. which is the set temperature at the start of the temperature increase process. The result of having measured the temperature of the rice in the center of the bottom inside the inner pot 30 and each part in the inner pot 30 is shown in FIG. In the case of the comparative example showing the temperature change in FIG. 6, the water absorption process is performed for 15 minutes, and the blower fan is not operated in the water absorption process. Also in FIG. 6, the temperature of the same part as in FIG. 5 is shown by the same line type, the solid line 61 is the temperature at the bottom center inside the inner pot 30, and the dotted line 62 is the temperature of the rice located at the top of the inner pot 30. The alternate long and short dash line 63 indicates the temperature of rice in the central portion of the inner pot 30, and the alternate long and two short dashes line 54 indicates the temperature of rice located in the lower portion of the inner pot 30. Moreover, the rice cooking conditions after a temperature rising process were made into the same conditions as the case of FIG. 5 which demonstrated the rice cooking conditions of this embodiment including the operation | movement of a ventilation fan.

  As shown in FIG. 6, in the water absorption process of the comparative example, since the set temperature is set to 40 ° C. from the beginning, strong heating is performed from the beginning of the water absorption process, and the inner pot 30 after 4 minutes from the start of the water absorption process. A large overshoot exceeding 70 ° C. occurs at the temperature 61 at the center of the inner bottom. Moreover, the temperature of the rice inside the inner pot 30 has not reached the set temperature of 40 ° C. in the upper part 62, the central part 63, and the lower part 64 at the time when 15 minutes have passed since the end of the water absorption process. The temperature 62 of the rice in the upper part of the inner pot 30 is 38 ° C. or higher, whereas the temperature 62 of the rice in the lower part of the inner pot 30 is about 32 ° C. It can be seen that there is a temperature difference.

  If the water absorption step is performed at the set temperature in such a comparative example, the temperature at the time of water absorption is not sufficiently increased, so that a sufficient amount of water cannot be absorbed. On the other hand, in the rice cooker of the present embodiment showing the temperature change in FIG. 5, when setting the inner pan temperature rising through a plurality of temperature rising steps that gradually increase, and operating the blower fan in the water absorption process Compared with the case of the water absorption process at the set temperature of the comparative example showing the temperature change in FIG. 6, although there is a change depending on the total number of rice to be cooked, it can be confirmed that the water absorption rate has increased by 3% to 37%. It was.

  In addition, when the water absorption process is performed at the set temperature in the case of the comparative example shown in FIG. 6, the water absorption unevenness due to the temperature difference of the rice occurs in each place in the inner pot 30, so when cooking You can see that it leads to uneven cooking.

  FIG. 7 shows an inner pot in another embodiment for confirming the effect of operating the blower fan in the water absorption step and generating an air current around the inner pot 30 as used in the rice cooker 100 of the present embodiment. The result of having measured the temperature of the rice in the bottom part of 30 and each part in the inner pot 30 is shown.

  The rice cooking conditions in the rice cooker of another embodiment shown in FIG. 7 are different from the comparative example shown in FIG. 6 only in that the blower fan is operated in the water absorption process, and the set temperature is the water absorption process from the beginning of the water absorption process. The water absorption step was performed by setting the temperature to 40 ° C., which is the set temperature at the end of the step. In FIG. 7, the temperature measurement results at the same places as in FIGS. 5 and 6 are shown by the same line type, the solid line 71 is the temperature at the bottom center inside the inner pot 30, and the dotted line 72 is the upper part of the inner pot 30. The temperature of the rice located at 1, the one-dot chain line 73 indicates the temperature of the rice in the central portion of the inner pot 30, and the two-dot chain line 74 indicates the temperature of the rice located at the lower portion of the inner pot 30. As in the case of the rice cooker of this embodiment whose temperature measurement results are shown in FIG. 5, the operation control of the blower fan in the water absorption process in another example is performed by switching the operation of the two fans every 30 seconds. did. In addition, in another Example shown in FIG. 7, the rice cooking process after a temperature rising process is the rice cooking conditions in the rice cooker of this embodiment shown in FIG. 5, and the comparison which showed the temperature measurement result in FIG. The conditions were the same as the cooking conditions in the example.

  As shown in FIG. 7, in the water absorption process in another embodiment, although the set temperature is set to 40 ° C. from the beginning, since the blower fan is operated from the beginning of the water absorption process, the inner side of the inner pot 30 is 3 minutes after the start. Overshoot occurs at the temperature 71 at the center of the bottom of the glass, but it is lower than the overshoot temperature 70 ° C. in the case of the comparative example shown in FIG. Moreover, although the temperature of the rice inside an inner pot has not reached 40 degreeC of setting temperature at the upper part 72, the center 73, and the lower part 74 at the time of the water absorption process of 15 minutes, in each site | part in an inner pot, The temperature difference of the rice temperature is 3 ° C. or less, and it can be seen that the temperature difference of 6 ° C. or more in the comparative example can be reduced by half.

  From the temperature measurement result in the water absorption process in another embodiment shown in FIG. 7, the temperature of the rice in the inner pot is made uniform by operating the blower fan in the water absorption process and generating an air flow around the inner pot. It can be seen that the effect can be demonstrated.

  Moreover, when the temperature change in the comparative example shown in FIG. 6 is compared with the temperature change in another embodiment shown in FIG. 7, in FIG. 6, the temperature 62 of rice located at the upper part of the inner pot is the slowest. In contrast to FIG. 7, it can be seen that the temperature 72 of the rice in the upper part of the inner pot rises the fastest, whereas it starts to rise. On the other hand, in the comparative example of FIG. 6, the temperature 64 of the rice at the lower part of the inner pot once becomes the highest in the first half of the water absorption process and then becomes the lowest at the end of the water absorption process, but in another embodiment of FIG. The temperature 74 of the rice in the lower part of the inner pot always gradually increases in a low state as compared with the temperature of rice in other parts. From these things, it can confirm that the heat | fever of an inner pot bottom is transmitted well to the upper part of an inner pot by operating a ventilation fan in a water absorption process and producing airflow.

  Therefore, as shown in FIG. 4, even if it is not set so as to increase through a plurality of temperature rising stages in which the set temperature of the inner pot gradually increases, control is performed so that the blower fan is operated in the water absorption process. Therefore, it is possible to reduce the temperature difference of the rice in the difference in the place in the inner pot, it is possible to suppress the unevenness of the water absorption rate for each place and effectively reduce the occurrence of uneven cooking during cooking. Understandable.

  As shown in FIG. 4 as the temperature 42 of the center sensor 26 and as the temperature 51 at the bottom center inside the inner pot 30 in FIG. 5, the set temperature rises stepwise as a plurality of temperature rising stages. Even when set in this way, the actual temperature of the inner pot 30 does not show a beautiful step-like change like the set temperature 41 in FIG. As described above, this is because the heating control means controls the on / off of the heating means while judging the relationship between the temperature of the center sensor 26 and the set temperature. This is because the temperature of the pan rises up and down repeatedly with respect to the set temperature. Therefore, in the present invention, when the temperature of the inner pot is expressed as “rising through a plurality of temperature rising stages that gradually increase”, the temperature is constant for a certain period of time as shown by a straight line 41 in FIG. Is maintained and rises on the staircase, as shown by the dotted line 42 in FIG. 4 and the straight line 51 in FIG. 5, the average temperature gradually rises through the steps while repeating small undulations. Including temperature changes. Then, this single undulation is regarded as one stage of temperature increase.

  FIG. 8 can be used for the rice cooker of this embodiment. It is a side view which shows the shape of the modification of an inner pot.

  The inner pot 31 of the modification shown in FIG. 8 has a streak-like groove 32 formed in the middle portion in the vertical direction of the outer surface of the inner pot 31. Thus, by providing the groove 32 on the outer surface of the inner pot, the contact area between the air heated when the blower fan is operated and the inner pot 31 is increased. For this reason, when the inner pot 31 heated by the coil or the air heated by the heater moves as an air current in the gap between the inner pot accommodating portion 20a and the inner pot 20, the surface of the inner pot 31 is heated. Can be improved, and the effect of uniformizing the temperature of the inner pot during the operation of the blower fan can be further improved.

  In addition, since it is thought that the effect of the temperature rise by the airflow produced | generated around the inner pot can be improved by increasing the surface area of an inner pot, in addition to forming a groove | channel as shown in FIG. The same effect can be expected even if a ridge-shaped convex portion is formed around the rim. Moreover, in the inner pot 31 of the modified example shown in FIG. 8, the groove is formed in an oblique direction, but the angle and length of the groove, the arrangement position in the inner pot 31 is not limited to that shown in FIG. It can select suitably according to the intensity | strength, direction, etc. of the airflow produced around an inner pot.

  The rice cooker of the present invention has been described above by exemplifying the case where a nonmetallic earthenware pot is used as the inner pot. However, the inner pot of the rice cooker of the present invention is not limited to an earthen pot made of non-metallic ceramics, and a metal pot mainly made of a metal material such as stainless steel or copper can be used.

  In addition, as the rice cooker of the present embodiment, the example provided with the blower fan that sends air into the gap between the inner pot accommodating portion and the inner pot to generate the airflow has been described, but without the blower fan, By setting the set temperature of the water absorption process so that the temperature of the inner pot gradually rises through a plurality of temperature rising stages as shown in FIG. 4, the temperature of the inner pot can be made uniform. Moreover, generation | occurrence | production of a strong overshoot can be suppressed, water absorption on uniform water absorption conditions can be performed, and the rice cooker which can reduce cooking unevenness can be obtained.

  In addition, in the said embodiment, although the setting temperature at the time of a water absorption process start was illustrated and demonstrated what was 30 degreeC in FIG. 4, and 25 degreeC in FIG. 5, in the rice cooker of this embodiment, at the time of a water absorption process start. The set temperature is not limited to these temperatures. The set temperature at the start of the water absorption process is equal to or higher than the room temperature before the start of rice cooking, and the temperature at which the rice cooking process starting from the water absorption process can be started without excessively applying strong thermal power at the start of rice cooking can be appropriately set.

  Moreover, although the example which set the preset temperature at the time of the temperature rising process which complete | finishes a water absorption process as 40 degreeC was illustrated, the setting temperature at the time of a temperature rising process start is not restricted to 40 degreeC, and it is sufficiently efficient in a water absorption process It is possible to set an appropriate temperature at which good water absorption is possible. In general, in order to allow sufficient and more uniform water absorption to the rice in the inner pot, the set temperature in the water absorption process is preferably about 40 ° C to 50 ° C. It is important that the temperature of the pan is set to 50 ° C. or lower, and in the water absorption process at 50 ° C. or lower, the temperature of the inner pan rises through a plurality of temperature rising stages in which the temperature gradually rises. The set temperature at the end of the water absorption process, that is, the set temperature at the start of the temperature raising process can be set to 50 ° C. or higher. However, even in this case, the water absorption temperature is 50 ° C. or lower. It is important to control so that the temperature of the inner pot rises through a plurality of temperature raising steps at least in the previous stage of the step. Further, it is not necessary to set the temperature so as to increase through a plurality of temperature rising steps that gradually increase over the entire time of the water absorption process where the set temperature is 50 ° C. or less. There is no problem even if there is a part where the temperature of the inner pot does not go through a step-like temperature rising stage in which the temperature rises gently.

  Further, in the setting example of the set temperature shown in FIG. 4, the set temperature is divided into twelve temperature rising stages equally divided from t = 0 when the water absorption process is disclosed to t = 12 when the temperature rising process is started. An example of raising through the above was explained. Furthermore, in the embodiment whose temperature change is shown in FIG. 5, the temperature is raised through 15 temperature raising steps. However, the setting example of the set temperature in the rice cooker 100 of the present embodiment is not limited to that illustrated in FIG.

  First, the number of the temperature raising steps of the set temperature is not limited to the illustrated 12 steps or 15 steps, but the entire time of the water absorption process, the set temperature at the start of the temperature raising process, and the inner pot is made of metal or nonmetal Or according to various conditions, such as the arrangement position of a heating means and its heating capability, a suitable thing can be suitably selected in the range of about 2 steps to 18 steps. Of course, by increasing the number of temperature raising steps, the temperature of the inner pot can be raised in a more uniform and uniform manner, so that the number of temperature raising steps is more preferably 5 or more. . On the other hand, even if the temperature raising stage is set very finely, there is a limit to the temperature control of the inner pot, so considering that the time of the water absorption process is about 15 minutes, it is most likely to be divided into about 15 stages. It can be said that it is realistic.

  Further, in the study by the present inventors, there was no significant difference in the number of preferable temperature raising steps between the case where the air current was generated around the inner pot using the blower fan and the case where the air current was not generated. . However, since the temperature of the inner pot can be controlled in a more uniform state by generating an air current around the inner pot using the blower fan, when the air current is generated by the blower fan, the temperature rise stage of the set temperature The number may be reduced.

  Further, in the temperature raising stage of the set temperature, the constant time for maintaining the predetermined temperature in each stage does not need to be all constant as shown in FIG. 4, and can be set appropriately with a length. Further, the degree of increase in the set temperature when proceeding to the set temperature of the next stage, that is, the temperature difference from the previous temperature raising stage is not limited to be uniform, and a preferable temperature difference can be selected as appropriate. . In this case, it is preferable to set the set time at the first stage of the water absorption process, which is the time when the temperature rise of the inner pot starts, to be longer and set the temperature difference at the stage closer to the first to be smaller. Conceivable.

  Furthermore, in order to raise the temperature of an inner pot through several temperature rising steps, the heating control means demonstrated the example which carries out on / off control of a heating means once in one temperature rising step. In order to raise the temperature of the inner pot through a plurality of temperature raising stages that gradually rise, it is preferable to repeat the on / off control once in one temperature raising stage as described above, but in the rice cooker of the present invention, Needless to say, the control of the heating control means includes the case where the number of on / off times of the heating means does not necessarily match the number of stages of the temperature raising stage.

  In addition, in the above description, the case where white rice is used as the cooked rice has been described, but various ingredients such as beans and vegetables other than white rice, grains other than rice can be used as cooked rice, cooked rice, etc. In so-called rice with ingredients, delicious rice with ingredients based on a good water absorption process can be cooked.

  According to the rice cooker of the present invention, it is possible to cause the rice to be cooked in the inner pot to absorb water evenly in the water absorption step, which is useful for reducing uneven cooking.

DESCRIPTION OF SYMBOLS 20 Rice cooker main body 20a Inner pan accommodating part 23 Blower fan 24 Blower port 25 Heating means 26 Center sensor (temperature sensor)
30 inner pot

Claims (5)

An inner pot for containing the cooked rice, a rice cooker body having an inner pot accommodating portion for accommodating the inner pot so as to be removable, a heating means for heating the inner pot, and a temperature sensor for detecting the temperature of the inner pot. The heating control means for controlling the heating means so that the temperature of the inner pot detected by the temperature sensor becomes a predetermined set temperature, the blower fan, and the wind from the blower fan, A blower opening provided at the bottom of the inner pot accommodating portion or the lower portion of the side wall, and a blower fan controller for controlling the operation of the blower fan, which can be blown out without passing through the arrangement position of the heating means in the path between And
A plurality of the air outlets are arranged on a circumference centered on the center of the inner pot accommodating portion,
The blower fan control unit operates the blower fan in a water absorption process in which the temperature of the inner pot is 50 ° C. or less, and from the blower fan between the inner pot accommodating unit and the inner pot from the blower opening. A rice cooker characterized by feeding wind.   In the water absorption process in which the temperature of the inner pot is 50 ° C. or less, the heating control means is configured so that the temperature of the inner pot follows a set temperature that gradually increases through a plurality of temperature increasing steps that gradually increase. The rice cooker of Claim 1 which controls a heating means.   3. The rice cooker according to claim 2, wherein the number of steps of the temperature increase stage of the set temperature of the inner pot in the water absorption process in which the temperature of the inner pot is 50 ° C. or less is 5 or more.   3. The water absorption process in which the temperature of the inner pot is 50 ° C. or less, wherein the heating control unit repeats on / off of the heating unit a number of times according to the number of stages of temperature increase of the set temperature of the inner pot. Or the rice cooker of 3.   The rice cooker according to any one of claims 1 to 4, wherein the inner pot is made of a non-metallic material.

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