JP2013052143A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker cooking good-taste rice by suppressing uneven cooking.SOLUTION: The rice cooker includes a residual water volume determination means determining a residual water volume that is a water volume remaining inside a pot-like container. A rice cooking process includes a temperature rise step raising the temperature of a heated object inside the pot-like container 5 until the heated object boils. The temperature rise step includes: a preheat rise step of repeating high heating power and low heating power; and a postheat rise step of repeating the high heating power and the low heating power in a shorter time than the low heating power in the preheat rise step. When it is determined that residual water inside the pot-like container 5 decreases to a volume not more than a prescribed volume by the residual water volume determination means while executing the preheat rise step of the heat rise step, a control means 8 transfers to the postheat rise step.

Description

  The present invention relates to a rice cooker in which a pot-like container containing food such as rice is housed in a main body and cooked.

  The function that the user who uses the rice cooker wants the rice cooker is to cook delicious rice. The texture, especially hardness, has a great influence on the taste of cooked rice. Therefore, it is very important to cook cooked rice with a favorable texture for the user.

However, it is not preferable in terms of taste if uneven cooking occurs such that some cooked rice in the pan-like container is hard and some cooked rice is soft.
For this reason, the rice cooker which can perform rice cooking control without cooking unevenness is desired.

  Therefore, conventionally, as a rice cooker for the purpose of improving the convection of the entire cooked object in the pan-like container and improving cooking unevenness, “the first heating means for heating the bottom surface of the pan, and the first A second heating means that is located outside the heating means and heats the bottom side surface portion or the bottom outer peripheral portion of the pan; and a control means that controls energization of the first and second heating means, the control means Has proposed a rice cooker that exclusively energizes the first and second heating means at least in the rice cooking step. This conventional rice cooker energizes the second heating means and the first heating means in a predetermined energization cycle (30 seconds or more) in the cooking process, and the second in the power-down process following the cooking process. The energization cycle of the heating means and the first heating means is made shorter than the energization cycle of the cooking process (for example, see Patent Document 1).

JP-A-10-262816 (4th page, 5th page, FIG. 2)

Here, immediately before and immediately after the boiling of water in the pot-shaped container, there is little water (residual water) left without being absorbed by the rice inside the pot-shaped container. If it is not evenly dispersed inside the container, uneven cooking tends to occur.
However, in the rice cooker described in Patent Document 1, since the power is down immediately after detecting boiling in the cooking process, a small amount of residual water does not reach the inside of the pan-like container, and the residual water is at the bottom of the pan. It is easy to collect in. For this reason, the lower cooked rice tends to be soft and the upper cooked rice tends to be hard, and the occurrence of uneven cooking could not be suppressed. In addition, the amount of water remaining in the pan-like container is not taken into account in the heating control, which is insufficient for suppressing cooking unevenness.

  This invention was made | formed in order to solve the above subjects, and provides the rice cooker which can cook rice with good taste by suppressing cooking unevenness.

  A rice cooker according to the present invention drives a main body, a pot-shaped container accommodated in the main body, a lid covering the opening of the pot-shaped container, a heating means for heating the pot-shaped container, and the heating means. A control means for controlling and executing the rice cooking process; and a remaining water amount judging means for judging a remaining water amount that is an amount of water remaining in the pot-like container, wherein the rice cooking process is heated in the pot-like container. A temperature raising step for raising the temperature of the product until it boils, the temperature raising step comprising: a first step that repeats a high thermal power and a low thermal power; a low thermal power that is shorter than the high thermal power and the low thermal power of the first step; The control means is configured to reduce the residual water in the pan-like container to a predetermined amount or less by the residual water amount determination means during execution of the first step of the temperature raising step. If it is determined that it is, the process proceeds to the second step.

  According to the present invention, in the first step of the temperature raising step, the heating means is controlled so as to repeat the high heating power and the low heating power. Further, when the remaining water is reduced to a predetermined amount or less during execution of the first step, the heating means is controlled to repeat the low heating power and the high heating power in a time shorter than the time of the low heating power in the first step. For this reason, in the first step of the temperature raising step, the generation of convection can be promoted in the pan-like container, and in the second step where the amount of remaining water is relatively small, the remaining water is prevented from collecting in a part of the pan-like vessel. it can. Therefore, it is possible to cook cooked rice in a delicious state with improved cooking unevenness.

It is a cross-sectional schematic diagram which shows the structure of the rice cooker which concerns on Embodiment 1. FIG. It is a front view of the operation display part of the rice cooker which concerns on Embodiment 1. FIG. It is a figure which shows the transition of the temperature of the to-be-heated material and the temperature of a pan-shaped container in the rice cooking process which concerns on Embodiment 1, and the electricity supply to a heating coil. It is a flowchart explaining the rice cooking operation | movement of the rice cooker which concerns on Embodiment 1. FIG. It is a cross-sectional schematic diagram which shows the pot-shaped container and the rice and water which are to-be-cooked objects at the time of the preheating process start which concerns on Embodiment 1. FIG. It is a cross-sectional schematic diagram which shows the pot-shaped container and the rice and water which are to-be-cooked objects at the time of the preheating process which concerns on Embodiment 1. FIG. It is a cross-sectional schematic diagram which shows the pot-shaped container and the rice and water which are to-be-cooked objects at the time of completion | finish of the process before temperature rising which concerns on Embodiment 1. FIG. It is a flowchart explaining the rice cooking operation | movement of the rice cooker which concerns on Embodiment 2. FIG. It is a figure which shows the electricity supply pattern to the heating coil of the temperature rising process of the rice cooker which concerns on Embodiment 3. FIG. It is a figure explaining the heating coil which concerns on Embodiment 4. FIG. It is a figure which shows the electricity supply pattern to the heating coil of the temperature rising process of the rice cooker which concerns on Embodiment 4. FIG. It is a figure which shows the modification of the electricity supply pattern to the heating coil of the temperature rising process of the rice cooker which concerns on Embodiment 4. FIG. It is a figure explaining the heating coil which concerns on Embodiment 5. FIG.

  Hereinafter, embodiments of a rice cooker according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a rice cooker according to Embodiment 1.
In FIG. 1, a rice cooker 100 includes a main body 1 whose outer appearance is formed in a bottomed cylindrical shape and a lid body 10, for example. The lid 10 has an outer lid 10a and an inner lid 10b. The main body 1 includes a container cover 2, a heating coil 3 as a heating means provided at the bottom of the main body 1, a pan bottom temperature sensor 4, a hinge portion 6 that supports the lid so that it can be opened and closed, and a time measuring means 7. The control means 8 is provided. As a heating means, an electric heater such as a sheathed heater may be provided in place of the heating coil 3.

  The container cover 2 is formed in a bottomed cylindrical shape, and the pot-shaped container 5 is detachably accommodated therein. In the center of the bottom of the container cover 2, a hole 2a for inserting the pan bottom temperature sensor 4 is provided. The pan bottom temperature sensor 4 is composed of, for example, a thermistor. The pan bottom temperature sensor 4 is biased upward by an elastic means such as a spring and is configured to come into contact with the bottom surface of the pan-like container 5 accommodated in the container cover 2. Information regarding the temperature of the pot-like container 5 detected by the pot bottom temperature sensor 4 is output to the control means 8. In the first embodiment, the pot bottom temperature sensor 4 detects the temperature of the pot-like container 5 by detecting the temperature of the pot-bottom container 5, but the configuration for detecting the temperature of the pot-like container 5 is this. It is not limited to, It is also possible to detect the temperature of parts other than the pan bottom.

  An operation / display unit 13 is provided on the upper surface of the outer lid 10a. The cartridge 12 is detachably attached to an attachment portion that penetrates the outer lid 10a and the inner lid 10b. The cartridge 12 includes a steam inlet 12a having a valve that moves up and down according to the steam pressure generated during rice cooking, and a steam outlet 12b that discharges the steam that has passed through the valve of the steam inlet 12a to the outside. Is provided.

  The inner lid 10b is attached to the surface of the outer lid 10a on the main body 1 side via a locking member 11. A lid packing 9 made of a sealing material is attached to the peripheral edge of the inner lid 10b to ensure hermeticity with the flange portion 5a formed on the outer periphery of the upper end of the pan-like container 5. Further, an internal temperature sensor 14 made of, for example, a thermistor for detecting the temperature of the object to be heated in the pan-like container 5 is attached to the inner lid 10b. Information regarding the temperature in the pan-like container 5 detected by the internal temperature sensor 14 is output to the control means 8. In the first embodiment, the temperature of the object to be heated is detected by the internal temperature sensor 14 attached to the inner lid 10b. However, any temperature detecting device can be used as long as the temperature of the object to be heated can be detected. Can be provided at any location.

  The time measuring means 7 is instructed by the control means 8 and counts the elapsed time. The elapsed time counted by the time measuring means 7 is output to the control means 8.

The control means 8 controls the overall operation of the rice cooker in addition to controlling the high-frequency current to be supplied to the heating coil 3 based on the outputs from the pan bottom temperature sensor 4, the operation / display unit 13, and the internal temperature sensor 14.
The control means 8 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU and software executed thereon.

  Moreover, in this Embodiment 1, the control means 8 determines the residual water amount in the pot-shaped container 5 during heating based on the temperature of the to-be-heated object detected by the internal temperature sensor 14 (details are mentioned later). ). In the first embodiment, the control means 8 and the internal temperature sensor 14 correspond to the remaining water amount determination means of the present invention.

Next, the operation / display unit 13 will be described.
FIG. 2 is a front view of the operation / display unit 13 of the rice cooker according to the first embodiment. A liquid crystal display panel 31 is disposed at the approximate center of the operation / display unit 13. On the liquid crystal display panel 31, a time, a rice seed display 32, a hardness display 33, and a menu display 34 are displayed. A rice seed switch 35, a hardness switch 36, a menu switch 37, and a cut / warm switch 38 are provided on the left side of the liquid crystal display panel 31. A rice cooking switch is provided on the right side of the liquid crystal display board 31. 39, a reservation switch 40, and a time switch 41 are provided. In addition, the specific names, the number of items, etc., such as the rice seed | species, hardness, menu, etc. which are shown in FIG. 2 are examples, and are not limited to what was illustrated.

  The rice seed switch 35 is an input means for setting the type of rice to be cooked. Each time the rice seed switch 35 is pressed, the display of the rice seed display 32 is switched to “white rice”, “non-washed rice”, “germinated brown rice”, or “brown rice”. Information regarding the type of rice set by the rice type switch 35 is output to the control means 8.

  The hardness switch 36 is an input means for setting the hardness after cooking. Each time the hardness switch 36 is pressed, the display of the hardness display 33 is switched to “normal”, “warming”, or “soft”. The information regarding the cooked hardness input to the hardness switch 36 is output to the control means 8, and the control means 8 selects the cooked hardness.

  The menu switch 37 is an input means for setting a rice cooking menu. Each time the menu switch 37 is pressed, the display of the menu display 34 is switched to “quick cooking”, “rice porridge”, or “cooking”. Information regarding the rice cooking menu set by the menu switch 37 is output to the control means 8.

  The off / heat retention switch 38 is an input means for switching the end / start of the heat retention operation, the rice cooking switch 39 is an input means for instructing the start of rice cooking, the reservation switch 40 is an input means for setting a rice cooking reservation, and a time switch 41 Is an input means for setting a time such as the current time or a reservation time. Information set by the off / heat keeping switch 38, the rice cooking switch 39, the reservation switch 40, and the time switch 41 is output to the control means 8.

Next, operation | movement of the rice cooking process of the rice cooker which concerns on this Embodiment 1 is demonstrated.
As described above, the rice cooker according to the first embodiment can set the kind of rice, the hardness of the cooked rice, and the rice cooking menu. Based on these set conditions, the control means 8 is a heating coil. 3 is performed to control the energization to the rice cooking process.

  FIG. 3 is a diagram showing the transition of the internal temperature of the pot-shaped container and the temperature of the pot-shaped container and the energization power to the heating coil 3 in the rice cooking process according to the first embodiment. In the first embodiment, the internal temperature of the pan-shaped container 5 (temperature of the object to be heated) is detected based on the detection value of the internal temperature sensor 14, and the temperature of the pan-shaped container 5 is detected as the pot bottom temperature sensor 4. Detection is based on the detected value. Moreover, FIG. 4 is a flowchart explaining the rice cooking process of the rice cooker which concerns on Embodiment 1. FIG. Hereinafter, operation | movement of the rice cooking process of the rice cooker which concerns on Embodiment 1 is demonstrated with reference to FIG. 3, FIG. 4 suitably.

First, each process which comprises a rice cooking process is demonstrated roughly.
As shown in FIGS. 3 and 4, the rice cooking process of the rice cooker according to the first embodiment includes a preheating process (step S1 in FIG. 4), a temperature raising process (step S2 in FIG. 4), and a high fire process (FIG. 4). Step S5), a low heat process (Step S6 in FIG. 4), a dry-up process (Step S7 in FIG. 4), and a steaming process (Step S8 in FIG. 4). The temperature raising step includes a pre-temperature raising step (step S3 in FIG. 4) and a post-temperature raising step (step S4 in FIG. 4). In addition, the process before temperature increase corresponds to the first process of the present invention, and the process after temperature increase corresponds to the second process of the present invention.

  The preheating process is a stage before the water in the pot-like container 5 boils, and the pot-like container 5 is heated at a predetermined temperature for a predetermined time, thereby promoting water absorption of the rice, and sugar and umami components as sweet ingredients It is the process of producing | generating taste components, such as an amino acid. In the preheating step, the control means 8 adjusts the temperature by repeatedly energizing the heating coil 3 and cutting off the power so that the temperature of the pan-like container 5 becomes a predetermined preheating temperature T. Here, the preheating temperature T is a temperature (for example, less than about 60 ° C.) at which the temperature of the water in the pan-like container 5 can be maintained at a temperature at which rice gelatinization does not start.

The temperature raising step is a step from the end of the preheating step until the water in the pan-like container 5 boils. The temperature raising step includes a pre-temperature raising step and a post-temperature raising step.
In the pre-temperature raising step, water absorption of rice proceeds rapidly and gelatinization starts, so that the amount of water (referred to as residual water) remaining without being absorbed by the rice in the pan-like container 5 gradually decreases. If the temperature distribution inside the pot-like container 5 is non-uniform, the water absorption state becomes non-uniform so that when it is cooked, it becomes hard and soft, that is, cooking unevenness occurs. In order to cook deliciously, it is important to reduce the temperature unevenness inside the pan-like container 5 in the temperature raising step, and for that purpose, it is necessary to generate convection of water by heating in the step before temperature raising. . The heating control for realizing such a pre-temperature rise process will be described later.
Moreover, the water absorption of the rice further proceeds in the post-temperature increase process, and the amount of residual water further decreases from that in the pre-temperature increase process. At this time, if the rice comes above the surface of the water, the cooked portion of the rice that has not been soaked in water becomes hard, so in this post-heating step, the rice is always kept in the remaining water. This is very important. The heating control for realizing the post-temperature raising process will be described later.

  When the water in the pot-like container 5 boils, it enters a high-fire process. In this high fire process, boiling is maintained by heating for a predetermined time with a predetermined power so that the temperature in the pot-shaped container 5 becomes a predetermined temperature equal to or higher than the boiling temperature at which the cooked rice can be kept boiling, and the remaining water is stored in the pot-shaped container. 5 evenly.

  In the low heat process, the remaining water is almost absorbed by the rice, and in this state, the boiling temperature is maintained for a predetermined time to promote gelatinization of rice starch.

  The dry-up process is a process for removing excess water. When it reaches the temperature (dry-up determination temperature) at which it is determined that there is no excess water in the pan-like container 5 and a dry-up state is reached, the process proceeds to the steaming step. When the predetermined time elapses in the steaming process, the cooking is finished.

Next, along FIG. 4, the rice cooking operation of the rice cooker according to the first embodiment will be further described.
First, the user stores a pan-like container 5 containing a predetermined amount of rice and a water amount corresponding to the amount of rice in the container cover 2 in the main body 1, closes the outer lid 10 a, and operates / displays 13. When the rice cooking switch 39 is pressed and an operation instruction for starting rice cooking is performed, the rice cooking process is started.

When the rice cooking switch 39 is turned on by the user and the start of rice cooking is instructed, the control means 8 proceeds to the preheating step.
FIG. 5 shows a schematic cross-sectional view of the pot-like container 5 and the cooked rice and water at the start of the preheating process. At this time, the top surface R of the rice that is substantially horizontal with respect to the bottom surface of the pan-like container 5 is separated from the water surface W by a distance A, and the entire rice is in a state of being immersed in water.

  In the preheating process of step S1, the control means 8 starts measuring the elapsed time of the preheating by the time measuring means 7, and uses the predetermined power P1 so that the temperature detected by the pan bottom temperature sensor 4 maintains the predetermined preheating temperature T. The heating coil 3 is energized and the power is cut off repeatedly to adjust the temperature of the pan-like container 5 (see FIG. 3). Then, when the elapsed time measured by the time measuring means 7 reaches a predetermined preheating time, the control means 8 proceeds to a temperature raising step in step S2.

  Here, FIG. 6 shows a schematic cross-sectional view of a pot-shaped container and cooked rice and water at the end of the preheating step. At this time, the upper surface R of the rice that is substantially horizontal with respect to the bottom surface of the pan-like container 5 is separated from the water surface W by a distance of 0.45A to 0.65A, and the entire rice is in a state of being immersed in water. However, the distance is shorter than the preheating process start time (see FIG. 5).

In the temperature raising step in step S2, first, the step before temperature raising in step S3 is executed.
In the pre-temperature raising step, the control means 8 energizes the heating coil 3 with the predetermined power P2 at the energization rate A / (A + B) (S31). Here, A is the energization time to the heating coil 3 (high heating time in the process before temperature increase), and B is the energization stop time to stop energization to the heating coil 3 (low heating time in the process before temperature increase). is there. That is, the control means 8 heats by the heating pattern (pre-process pattern) which repeats alternately a high thermal power state and a low thermal power state by repeating energization of the predetermined power P2 to the heating coil 3 and the energization stop. In order to cause convection of water in the pan-like container 5 by heating, a heating pattern in which the energization state (high thermal power state) is set for a relatively long time and then the energization stop state (low thermal power state) is set for a relatively long time is preferable. In the first embodiment, for example, A = 40 seconds, B = 20 seconds, and convection in the pan-like container 5 is promoted by repeating intermittent operation of energizing for 40 seconds and then stopping for 20 seconds. Instead of realizing low thermal power by stopping energization of the heating coil 3, low thermal power may be achieved by energizing the heating coil 3 with lower electric power than during high thermal power.

In heating before step, the control unit 8, the detection temperature T ₀ of the internal temperature sensor 14 is equal to or a predetermined threshold above T _1, the detected temperature T ₀ is the threshold value T ₁ of the internal temperature sensor 14 When it determines with it being above (S32; Yes), it progresses to the process after temperature rising of step S4. In step S32, the remaining water amount in the pan-like container 5 is determined based on the detected temperature T ₀ of the internal temperature sensor 14.

The determination of the remaining water amount based on the temperature detected by the internal temperature sensor 14 utilizes the fact that the remaining water amount can be estimated from the water absorption state of rice. In general, the water absorption of rice is determined by the relationship between temperature and time in the rice cooking process. Therefore, the relationship between the temperature of the object to be heated (rice and water) in the pan-like container 5 when the predetermined power P2 is energized to the heating coil 3 with an energization rate A / (A + B) by experiments or the like in advance The temperature detected by the internal temperature sensor 14 when the predetermined remaining water amount is reached is stored as a threshold value T ₁ in a storage device (not shown). Then, the amount of remaining water in the pan-like container 5 is determined by comparing the threshold T ₁ stored in the storage device (not shown) with the detected temperature T ₀ of the internal temperature sensor 14.

  FIG. 7 is a schematic cross-sectional view showing a pot-like container, rice to be heated, and water at the end of the pre-temperature rise process. At this time, the top surface R of the rice that is substantially horizontal with respect to the bottom surface of the pan-like container 5 is separated from the water surface W by a distance of 0.3 A to 0.4 A, and the entire rice is in a state of being immersed in water. However, the distance is further shortened from the end of the preheating step (see FIG. 6). In addition, depending on the situation where the user sets the rice and water before cooking (for example, when the upper surface of the rice is set so as to be largely inclined), some rice grains may come out above the water surface. is there.

For example, as shown in FIG. 7, the amount of residual water in which the entire rice is immersed in water but the distance between the upper surface R of the rice and the water surface W is further reduced from the end of the preheating step is a predetermined residual water amount. Yes, the temperature detected by the internal temperature sensor 14 at this time becomes the threshold value T ₁ .
According to the experiment, when the temperature of the object to be heated (rice and water) becomes 70 ° C. and the state of the remaining water amount (for example, the state illustrated in FIG. 7) is shifted to the post-temperature increase process, It is known that it can be suppressed. Therefore, in the first embodiment, when the temperature of the object to be heated (rice and water) becomes 70 ° C. or higher, it is determined that the remaining water amount has decreased to a predetermined amount or less, and the process proceeds to the post-temperature increase process. In the first embodiment, the temperature of the object to be heated (rice and water) is detected based on the detection temperature of the internal temperature sensor 14, and when the temperature of the object to be heated (rice and water) is 70 ° C., the internal temperature sensor Since the detected temperature 14 indicates 60 ° C., the predetermined threshold T _{1 is set} to 60 ° C.

  The post-temperature increase process in step S4 is a process until the control means 8 detects boiling in the pan-like container 5 based on the detection information of the internal temperature sensor 14. When entering the post-temperature rise process, the control means 8 energizes the heating coil 3 with the predetermined power P3 at the energization rate C / (C + D) (S41). Here, C is the energization time to the heating coil 3 (high heating time in the process after the temperature increase), D is the energization stop time (low heating time in the process after the temperature increase) that stops the energization to the heating coil 3. is there. That is, the control means 8 heats with the heating pattern (post-process pattern) which repeats alternately a high thermal power state and a low thermal power state by repeating energization of the predetermined electric power P3 to the heating coil 3 and the energization stop.

  Here, the energization stop time D is a time shorter than the energization stop time B in the pre-temperature rise process (D <B). In the state where the remaining water is decreasing, when the heating coil 3 is energized (high thermal power state), the remaining water boils up to the top of the pan-like container 5 and the whole rice in the pan-like container 5 Is immersed in the remaining water, but when the energization is stopped (low thermal power state), the surface of the remaining water is lowered and the remaining water is accumulated in the lower portion of the pan-like container 5. When the remaining water level drops and the remaining water has accumulated in the lower part of the pan-like container 5 for a long time, that is, when the energization stop state for the heating coil 3 continues for a long time, the rice in the upper part of the pot-like container 5 is removed from the water surface. The upper part of the rice is dried up without being able to absorb water, and the difference in water absorption between the lower and upper rices in the pan-like container 5 opens. That is, when the energization stop state to the heating coil 3 is long, uneven water absorption occurs at the lower part and the upper part of the pan-like container 5 and causes uneven cooking. Therefore, while there is enough remaining water (that is, before the temperature rise), in order to promote convection as described above, after energizing for a relatively long time (high thermal power state), the energization is stopped for a relatively long time. In the post-temperature rise process where residual water is reduced, the heating control is performed with a heating pattern that shortens the time of low thermal power compared to the pre-temperature rise process. . By doing in this way, cooking unevenness can be suppressed in the pre-temperature raising step and the post-temperature raising step. In the first embodiment, the energization time C in the post-temperature increase process is shorter than the energization time A in the pre-temperature increase process, but the present invention is not limited to this.

  And if the control means 8 detects that the to-be-heated material in the pan-shaped container 5 boiled based on the detection temperature of the internal temperature sensor 14, it will progress to a high fire process (S5).

  In the strong fire process in step S5, the control means 8 energizes the heating coil 3 with the predetermined power P4 until the time measuring means 7 measures the passage of the predetermined time in the high fire process. The boiling state is maintained by heating with a predetermined power for a predetermined time, and the remaining water is made to uniformly reach the pot-shaped container 5.

  When the strong fire process of step S5 is completed, the process proceeds to the low fire process of step S6. In order to gelatinize rice, it is necessary to maintain at 98 ° C. or higher for 20 minutes. Therefore, in the low heat process of step S6, the control means 8 starts measuring the elapsed time by the time measuring means 7, and supplies the heating coil 3 with a predetermined power P5 so that the rice and water in the pan-like container 5 do not burn. Perform intermittent energization. When the elapsed time measured by the time measuring means 7 reaches a predetermined time, the control means 8 proceeds to a dry-up process in step S7.

  The dry-up process of step S7 is a process from the end of the low-fire process until the pan-like container 5 reaches the dry-up determination temperature. The control means 8 detects whether or not the pot-like container 5 has reached the dry-up determination temperature based on the detection information of the pot bottom temperature sensor 4. In the dry-up process, the control means 8 performs intermittent energization to the heating coil 3 with the predetermined power P6 so that the amount of power per unit time is higher than that in the low-fire process. When the control means 8 detects that the object to be heated in the pot-like container 5 has reached a predetermined dry-up determination temperature based on the temperature detected by the pot bottom temperature sensor 4, the control means 8 proceeds to the steaming step of step S8.

  In the steaming step of step S8, the control means 8 starts measuring the elapsed time by the time measuring means 7, and ends the rice cooking process when the elapsed time measured by the time measuring means 7 reaches a predetermined time.

  As described above, in the first embodiment, the energization pattern is switched between the pre-temperature increase process and the post-temperature increase process. And in the process before temperature rising with a relatively large amount of residual water, heating is performed with a heating pattern in which high and low heating power are repeated. For this reason, generation | occurrence | production of the convection of a to-be-heated material can be accelerated | stimulated in the pan-shaped container 5, and cooking unevenness can be suppressed. Further, when the residual water is reduced to a predetermined amount, the energization pattern is different from that before the temperature increase process, and heating is performed with a heating pattern that repeats low and high thermal power in a time shorter than the time of low heat power in the process before temperature increase. I did it. For this reason, it can suppress that a little residual water accumulates in a part in the pot-shaped container 5 in the post-temperature raising step, and the remaining water can be distributed more uniformly in the pot-shaped container 5. Moreover, in the post-temperature raising step, convection of the heated object in the pan-like container 5 is promoted by performing intermittent energization that repeats energization and energization stop even in a shorter time than the pre-temperature raising step. Can do. Therefore, temperature unevenness of the object to be heated is suppressed, and delicious cooked rice with less cooking unevenness can be provided to the user.

Further, in the first embodiment, the remaining water amount is used as a determination criterion for switching from the pre-temperature increase process to the post-temperature increase process and switching the energization pattern, and the internal temperature sensor 14 is configured as a configuration for determining this remaining water amount. The detected temperature was used. By using the internal temperature sensor 14, the amount of remaining water can be estimated without directly touching the cooked rice, which is hygienic.
Moreover, the timing which transfers to a post-temperature-raising process can be determined with high accuracy by estimating the amount of residual water based on the temperature of rice and water that are to be heated.

In the first embodiment, when the detected temperature of the internal temperature sensor 14 is equal to or higher than the predetermined value T ₁ = 60 ° C., it is determined that the remaining water amount is equal to or lower than the predetermined amount. The temperature of the object to be heated may be detected by using the temperature sensor 4 or a pan side surface temperature sensor (not shown) that detects the temperature of the pan side surface, and the remaining water amount may be determined based on the temperature. In that case, as described above, the control means 8 stores the temperature at the bottom of the pan and the side of the pan when the temperature of the rice and water reaches 70 ° C. as a predetermined threshold, and the temperature of the pan bottom temperature sensor 4 or pan side temperature sensor When it is determined that the detected temperature is equal to or higher than the predetermined threshold, the process may be shifted to a post-temperature increase process. Alternatively, a sensor that directly measures the temperature of rice or water may be used. In this case, the predetermined threshold T _{1 is set} to 70 ° C.

Embodiment 2. FIG.
In this Embodiment 2, the example which uses a time measurement means as a residual water amount determination means is shown. In the second embodiment, differences from the first embodiment will be mainly described, and the same or corresponding components as those in FIGS. 1 to 4 described above are denoted by the same reference numerals.

  FIG. 8 is a flowchart for explaining the operation of the rice cooking process of the rice cooker according to the second embodiment. Hereinafter, the rice cooking operation of the rice cooker according to the second embodiment will be described with reference to FIG.

  As shown in FIG. 8, when the rice cooking switch 39 is turned on by the user and the start of rice cooking is instructed, the control means 8 proceeds to the preheating process of step S <b> 1. The preheating process in step S1 is the same as that in the first embodiment.

  When the preheating process ends and the process proceeds to the temperature raising process in step S2, the process before temperature raising in step S3 starts. When the pre-temperature rise process is started, the control means 8 starts measuring the elapsed time by the time measuring means 7 (S31a), and energizes the heating coil 3 with the predetermined power P2 at the energization rate A / (A + B) ( S32a). When the time measuring means 7 determines that the predetermined elapsed time t1 has elapsed (S33a), the process proceeds to the next step S4 after the temperature increase. In step S33a, the amount of water remaining in the pan-like container 5 is determined based on the elapsed time since the start of the temperature increase pre-process.

  The determination of the amount of remaining water based on the elapsed time since the start of the pre-temperature rise process utilizes the fact that the amount of remaining water can be estimated from the water absorption state of rice. As described in Embodiment 1, the water absorption of rice is generally determined by the relationship between temperature and time in the rice cooking process. Therefore, in the second embodiment, instead of determining the remaining water amount based on the temperature of the object to be heated as in the first embodiment, the remaining water amount is determined based on the elapsed time. Specifically, the relationship between the elapsed time from the start of energization of the heating coil 3 with the predetermined power P2 at the energization rate A / (A + B) and the remaining water amount is examined in advance through experiments or the like. Is stored as a threshold elapsed time t1 in a storage device (not shown). Then, the amount of remaining water in the pan-like container 5 is determined by comparing the elapsed time t3 stored in the storage device (not shown) with the elapsed time measured by the time measuring means 7.

  According to the experiment, it is known that the uneven cooking can be most suppressed when the process proceeds to the post-temperature increase process at the timing 3 minutes after the start of the pre-temperature increase process (end of the preheating process). Therefore, in the second embodiment, the elapsed time t1 serving as the threshold is set as 3 minutes.

  The process from the post-temperature raising process in step S4 to the steaming process in S8 is the same as that in the first embodiment.

  As described above, according to the second embodiment, the uneven cooking can be suppressed as described in the first embodiment. Furthermore, in the second embodiment, the amount of residual water in the pan-like container 5 is determined by the time measuring means 7 based on the elapsed time of the pre-temperature increase process. For this reason, for example, the amount of residual water in the pan-like container 5 can be determined without directly touching the cooked rice with a member such as a temperature sensor, which is hygienic. In addition, the temperature sensor is placed near the object to be heated because it needs to measure the temperature of the object to be heated. For example, foreign matter (for example, rice) adheres to the temperature sensor's sensitive area and the temperature cannot be measured accurately. However, since such a problem does not occur in time measurement, there is a low probability that a measurement error, that is, a determination error of the remaining water amount will occur.

  Note that the determination of the remaining water amount based on the temperature of the object to be heated described in Embodiment 1 and the determination of the remaining water amount based on the elapsed time of the pre-temperature increase process described in Embodiment 2 may be used in combination. . In this case, when it is determined by either one that the remaining water amount is equal to or less than the predetermined amount, it is possible to shift from the pre-temperature increase step to the post-temperature increase step, or both the residual water amount is equal to or less than the predetermined amount. If it is determined that the process has been performed, the process may proceed from the pre-temperature increase process to the post-temperature increase process.

Embodiment 3 FIG.
In the third embodiment, a modification of the energization pattern in the post-temperature increase process will be described. The third embodiment will be described with a focus on the energization pattern of the post-temperature increase process, which is the difference from the first and second embodiments. The third embodiment can be combined with the first and second embodiments.
FIG. 9 is a diagram showing an energization pattern to the heating coil in the temperature raising process of the rice cooker according to the third embodiment.

In the first and second embodiments, the energization pattern of the energization rate C / (C + D) in which the energization is performed for the energization time C and the energization is stopped for the energization stop time D is shown as the energization pattern of the post-temperature increase process.
On the other hand, as shown in FIG. 9, the energization pattern of the post-temperature increase process according to the third embodiment is energized for a predetermined time C1 with electric power X and energized for a predetermined time D1 with electric power Y smaller than electric power X (D1). The heating pattern is <B). That is, repetition of high thermal power and low thermal power is realized by alternately energizing with relatively high power and energizing with relatively low power.

  By doing in this way, in this Embodiment 3, since the heating coil 3 will always be in an energized state in the post-temperature raising step, the temperature of the pot-like container 5 will not drop too much, and the remaining water will be in a pot-like form. It is possible to further suppress the accumulation in the bottom in the container 5. Therefore, the cooking unevenness of the upper part and the lower part in the pot-shaped container 5 can be suppressed.

Embodiment 4 FIG.
In the first to third embodiments described above, an example in which one heating means (heating coil 3) is provided at the bottom of the main body 1 (see FIG. 1) is shown. However, in the fourth embodiment, the bottom of the main body 1 is provided. A configuration example provided with a plurality of heating means will be described. In addition, since the rice cooker of this Embodiment 4 has the characteristics in the structure regarding a heating means, it demonstrates centering on this point. Other configurations can be combined with the first to third embodiments.
10A and 10B are diagrams for explaining the heating coil according to the fourth embodiment. FIG. 10A is a schematic cross-sectional view of the main part, and FIG. 10B is a schematic plan view of the heating coil.

  As shown in FIG. 10, in Embodiment 4, the heating coil 3a (heating part) and the heating coil 3b (heating part) arranged in a double ring shape are used as heating means for heating the pot-like container 5. Prepare. The heating coil 3 a has a substantially annular shape and is provided at a position corresponding to the inside of the bottom of the pan-like container 5. The heating coil 3b has a substantially annular shape having a larger diameter than that of the heating coil 3a, and is provided substantially concentrically with the heating coil 3a outside the heating coil 3a. The heating coil 3a and the heating coil 3b are independently driven and controlled by the control means 8 (see FIG. 1).

  FIG. 11 is a diagram illustrating an energization pattern to the heating coil in the temperature raising process of the rice cooker according to the fourth embodiment. FIG. 11A shows the energizing power to the heating coil 3a, FIG. 11B shows the energizing power to the heating coil 3b, and FIG. 11C shows the total energizing power (energizing power to the heating coil 3a and the heating coil 3b). This is the total value of power over time, and the same applies to the following description).

  First, the total value of the energized power of the heating coil 3a and the heating coil 3b shown in FIG. As shown in FIG. 11C, in the post-heating step, heating is performed with a heating pattern in which an energization time C2 for energizing the heating coil 3a or the heating coil 3b and an energization stop time D2 for stopping energization are alternately repeated. . In this post-temperature increase process, the energization stop time (low heating power time in the post-temperature increase process) D2 for stopping the energization of the heating coil 3a and the heating coil 3b is set to the low thermal power time B in the pre-temperature increase process. Is shorter (D2 <B). That is, as in the first embodiment, heating is performed with a heating pattern in which a low heating power in a time shorter than a low heating power time in the pre-temperature raising step and a high heating power are repeated. For this reason, like Embodiment 1, it can suppress that a little residual water accumulates in a part in the pan-like container 5 in a post-temperature-raising process, and the residual water is spread more uniformly in the pan-like container 5. Can be made.

  Next, the energization power to each of the heating coil 3a located inside the pan-like container 5 and the heating coil 3b located outside will be described. As shown in FIG. 11A, the control means 8 performs energization control with an energization pattern in which energization is stopped for the time D2a after energizing the heating coil 3a for the time C2a. Further, as shown in FIG. 11 (b), the control means 8 controls energization with an energization pattern in which energization is stopped for the time D2b after energizing the heating coil 3b for the time C2b. And the energization timing to the heating coil 3a and the heating coil 3b is controlled so that the heating coil 3a is energized only for the time C2a and then the heating coil 3b is energized only for the time C2b. Thus, in the post-temperature raising step, high heating power in the high-temperature post-step shown in FIG. 11C is realized by selectively energizing either the heating coil 3a or the heating coil 3b. By energizing the heating coil 3a located on the center side and the heating coil 3b located on the outside at different timings, convection can be promoted between the inside and outside of the pan-like container 5. For this reason, compared with the case where the one heating coil 3 is provided like Embodiment 1, the convection of the to-be-heated material in the pan-shaped container 5 can be further promoted. Therefore, temperature unevenness of the object to be heated is suppressed, and delicious cooked rice with less cooking unevenness can be provided to the user.

  Although FIG. 11 shows an example in which only the heating coil 3a is energized in the pre-temperature raising step, the heating coil 3a and the heating coil 3b may be energized alternately as in the post-temperature raising step. The energization control may be performed so that the total value of energization power to the heating coil 3a and the heating coil 3b is in the state shown in FIG. 11C, and the distribution of energization to the heating coil 3a and the heating coil 3b is set as appropriate. be able to.

  Next, a modification of the energization pattern to the heating coil in the temperature raising process shown in FIG. 11 will be described. FIG. 12 is a diagram illustrating a modification of the energization pattern to the heating coil in the temperature raising process of the rice cooker according to the fourth embodiment. 12A shows the energizing power to the heating coil 3a, FIG. 12B shows the energizing power to the heating coil 3b, and FIG. 12C shows the total energizing power to the heating coil 3a and the heating coil 3b (energization). This is the total value of power over time, and the same applies to the following description).

  The energizing power to the heating coil 3a shown in FIG. 12 (a) is the same as that in FIG. 11 (a), but the energizing power to the heating coil 3b shown in FIG. 12 (b) is different from that in FIG. 11 (b). . Specifically, in FIG. 12B, the energization power to the heating coil 3b is set to a value lower than the energization power to the heating coil 3a. Further, the energization time C2b to the heating coil 3b is set to be longer than the energization time C2a to the heating coil 3a (C2b> C2a), and the energization timing to the heating coil 3a and the energization timing to the heating coil 3b are set. A time for energizing the heating coil 3a and the heating coil 3b at the same time is provided. For this reason, the total value of the energization power to the heating coil 3a and the heating coil 3b is as shown in FIG. As can be seen by comparing FIG. 12 (c) and FIG. 11 (c), in FIG. 12 (c), the change in energized power in the post-temperature rise process becomes more complicated than in FIG. 11 (c). ing. For this reason, in the post-temperature raising step shown in FIG. 12, convection of the heated object in the pan-like container 5 can be promoted more than that shown in FIG. Therefore, temperature unevenness of the object to be heated is suppressed, and delicious cooked rice with less cooking unevenness can be provided to the user.

  Note that the total value of the energization power to the heating coil 3a and the heating coil 3b may be as shown in FIGS. 11C and 12C. For example, the heating coil shown in FIGS. The energizing power to 3a and the energizing power to the heating coil 3b may be interchanged.

Embodiment 5 FIG.
In the above-described fourth embodiment, the example in which the two heating units (heating coils 3a and 3b) are provided at the bottom of the pan-like container 5 has been shown. However, in the fifth embodiment, another arrangement example of the heating unit is illustrated. explain. In addition, since the rice cooker of this Embodiment 5 has the characteristics in the structure regarding a heating means, it demonstrates centering on this point. Other configurations can be combined with the first to third embodiments.
FIG. 13 is a diagram for explaining the heating coil according to the fifth embodiment. FIG. 13 (a) is a schematic cross-sectional view of the main part, and FIG. 13 (b) is a perspective view of the pan-like container and the heating coil. In FIG. 13B, the container cover 2 is not shown because of the illustration.

  As shown in FIG. 13, in the fifth embodiment, the heating coil 3 a (heating unit) is disposed at a position facing the bottom of the pan-like container 5. Further, the heating coil 3 b (heating unit) is disposed at a position facing the side surface of the pan-like container 5. Thus, in this Embodiment 5, the heating part is arrange | positioned at the bottom face and side surface of the pan-shaped container 5, respectively.

  Control of the energization power to the heating coils 3a and 3b can be performed in the same manner as in FIGS. 11 and 12 described in the fourth embodiment. In this way, in the post-temperature raising step, the convection between the inside and outside of the pot-shaped container 5 can be promoted by heating from both the bottom of the pot-shaped container 5 and the side surface of the pot-shaped container 5. it can. For this reason, compared with the case where the one heating coil 3 is provided like Embodiment 1, the convection of the to-be-heated material in the pan-shaped container 5 can be further promoted. Therefore, temperature unevenness of the object to be heated is suppressed, and delicious cooked rice with less cooking unevenness can be provided to the user.

  In the fourth and fifth embodiments, it has been described that no power is supplied to any of the heating coils 3a and 3b during the low heating power in the post-temperature raising process. However, in the same manner as shown in the third embodiment, the total value of the energization power to the heating coils 3a and 3b is smaller at the time of low heating power in the post-temperature raising process than at the time of high heating power in the post-temperature raising process. In this way, one or both of the heating coils 3a and 3b may be energized. Even if it does in this way, the same effect can be acquired.

  In the fourth and fifth embodiments, the example in which two heating coils are provided has been described. However, three or more heating coils may be provided. For example, three heating coils having different diameters may be provided on the bottom surface of the pan-like container 5 in a substantially concentric manner to form a triple ring structure. For example, a heating coil having a double ring structure as shown in the fourth embodiment is provided on the bottom surface of the pan-like container 5, and a heating coil is also provided at a position facing the side surface of the pot-like container 5. Good. Even in the case where three or more heating coils are provided in this way, the low heating time in the post-heating process is shorter than the low heating time in the pre-heating process, so that The same effect can be obtained by selectively driving one or more of them.

  In the first to fifth embodiments, the example in which the heating coil is used as the heating unit has been described. However, an electric heater such as a sheathed heater may be used instead of the heating coil. In this case, the heating control is performed in the pre-heating step and the post-heating step so as to alternately repeat a relatively large state (high thermal power state) and a small state (low thermal power state) of the electric heater. Do.

  In the first embodiment, the remaining water amount is determined based on the temperature detected by the internal temperature sensor 14, and in the second embodiment, the remaining water amount is determined based on the elapsed time measured by the time measuring means 7. A water level sensor that detects the water level in the container 5 may be provided to determine the remaining water amount based on the water level. For example, when a water level sensor that measures the water level using a contact method is used, the distance from the bottom surface of the pan-like container 5 to the top surface R of the rice and the distance to the water surface W is detected, and the residual from the difference between these two distances. The amount of water can be determined. By directly measuring the water level using a water level sensor, it is possible to accurately determine the amount of residual water with little influence of water absorption characteristics of rice due to rice varieties, freshness, etc., and more reliably suppressing the occurrence of uneven cooking. it can.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Container cover, 2a Hole part, 3 Heating coil, 3a Heating coil, 3b Heating coil, 4 Pan bottom temperature sensor, 5 Pan-shaped container, 5a Flange part, 6 Hinge part, 7 Time measuring means, 8 Control means, 9 lid packing, 10 lid, 10a outer lid, 10b inner lid, 11 locking material, 12 cartridge, 12a steam inlet, 12b steam outlet, 13 operation / display section, 14 internal temperature sensor, 31 liquid crystal display board, 32 Rice display, 33 Hardness display, 34 Menu display, 35 Rice switch, 36 Hardness switch, 37 Menu switch, 38 OFF / Heat switch, 39 Rice cooker switch, 40 Reservation switch, 41 Time switch, 100 Rice cooker.

Claims (11)

The body,
A pot-shaped container accommodated in the main body;
A lid covering the opening of the pan-like container;
Heating means for heating the pan-like container;
Control means for controlling the heating means to perform the rice cooking process;
A residual water amount determination means for determining a residual water amount that is the amount of water remaining in the pan-like container;
The rice cooking step includes a temperature raising step of raising the temperature of the heated object in the pan-like container until it boils,
The temperature raising step includes a first step that repeats high thermal power and low thermal power, and a second step that repeats high thermal power and low thermal power in a shorter time than the low thermal power of the first step,
The control means includes
If the residual water amount determination means determines that the residual water in the pan-like container has decreased below a predetermined amount during execution of the first step of the temperature raising step, the process proceeds to the second step. A rice cooker characterized by that. The said control means stops the electricity supply to the said heating means at the time of the low heating power of said 2nd process. The rice cooker of Claim 1 characterized by the above-mentioned. The control means is configured to energize the heating means when the second process has a low heating power for a time shorter than the power of the second process at a high heating power for a time shorter than the low heating power of the first process. The rice cooker of Claim 1 characterized by the above-mentioned. The said control means stops the electricity supply to the said heating means at the time of the low thermal power of said 1st process. The rice cooker as described in any one of Claims 1-3 characterized by the above-mentioned. The residual water amount determination means includes
A temperature detecting means for detecting the temperature of the object to be heated in the pot-shaped container or the temperature of the pot-shaped container;
The rice cooker according to any one of claims 1 to 4, wherein the remaining water amount that decreases as the detected temperature increases is determined based on the detected temperature of the temperature detecting means. The residual water amount determination means includes
Temperature detecting means for detecting the temperature of the object to be heated in the pot-shaped container or the pot-shaped container;
Storage means for storing the temperature detected by the temperature detection means when the residual water reaches the predetermined amount;
The residual water amount is determined by comparing the detected temperature of the temperature detecting means with the detected temperature stored in the storage means. The described rice cooker. The residual water amount determination means includes
Comprising a time measuring means for measuring an elapsed time from the start of the first step,
The rice cooker according to any one of claims 1 to 4, wherein the remaining water amount that decreases as the elapsed time becomes longer is determined based on the elapsed time measured by the time measuring means. The residual water amount determination means includes
A time measuring means for measuring an elapsed time from the start of the first step;
Storage means for storing the elapsed time of the time measuring means when the residual water reaches the predetermined amount,
The residual water amount is determined by comparing the elapsed time measured by the time measuring means with the elapsed time stored in the storage means. Rice cooker according to item. The heating means is composed of a plurality of heating units that are independently driven and controlled,
The said control means performs said 1st process and said 2nd process by selectively driving one or more things of these heating parts. Item 9. The rice cooker according to any one of items 8. Two of the plurality of heating units are formed in a substantially annular shape having different diameters, and are arranged substantially concentrically at positions facing the bottom surface of the pan-like container. 9. Rice cooker according to 9. One of the plurality of heating units is provided at a position facing the bottom surface of the pan-like container,
The other one of the plurality of heating units is provided at a position facing a side surface of the pan-like container.

Images