JP6974112B2 - rice cooker - Google Patents

Description

The present invention relates to a rice cooker that executes rice cooking in the order of a pre-cooking process, a main cooking process, a cooking process, and a steaming process, and controls this rice cooking based on the temperature detection of the inner pot.

Conventionally, this type of rice cooker generally has an inner pot that opens upward and allows rice and water to enter inside, a main body that can store the inner pot inside and has a lid that covers the inner pot from above, and the inside. It has a heating means for heating the pot, a temperature detecting means for detecting the temperature of the inner pot, and a control means for controlling heating by the heating means. Execute in order. Generally, the pre-cooking process is a process of raising the water temperature over low heat to infiltrate the rice in order to increase the water absorption rate of the rice, and the main cooking process is a process of boiling water over high heat and adding water and heat to the rice. , A step of changing β-starch to α-starch. In addition, the cooking step is a step of reducing the heat again to reduce the heat to promote the pregelatinization of rice, and the steaming step is a step of extinguishing the fire and leaving it to stand until the temperature drops to the heat insulating temperature. In the control means, rice cooking conditions such as temperature and time suitable for cooking rice are set in advance for each of the above steps based on empirical values and the like.

In particular, there is a rice cooker that allows a rice cooker net to be laid on the inner bottom of the inner pot, such as a commercial rice cooker (see, for example, Patent Document 1). This rice cooker is provided with a net receiver that prevents the rice cooking net from coming into contact with the upper surface of the rice layer inside the inner pot, and suppresses premature cutting in which the rice cooking switch is turned off before the rice is cooked.

However, in the above rice cooker, since the rice is cooked by putting a rice cooking net inside the inner pot, the change in the temperature of the inner pot detected by the temperature detecting means in the main cooking process is different from the case of normal rice cooking, and the rice is cooked earlier. There is a problem that the heat is switched and the firepower is switched. Therefore, it was an obstacle to cooking rice with the desired taste.

Japanese Unexamined Patent Publication No. 07-227352

In view of the above points, the present invention accurately shifts from the main cooking process to the cooking process even when the rice is cooked by putting the rice cooking net inside the inner pot, and it is possible to cook the rice with the desired taste. The challenge is to provide a rice cooker that can do it.

In order to solve the above problems, the present invention includes an inner pot that opens upward and allows rice and water to enter inside, and a main body that can store the inside of the inner pot and has a lid that covers the inner pot from above. It has a temperature detecting means for detecting the temperature of the inner pot, a heating means for heating the inner pot, and a control means for controlling heating by the heating means. In the rice cooker that is executed in the order of, the control means are the time measuring means for measuring the time from the start of rice cooking, the elapsed time from the start of rice cooking in the main cooking process, and the temperature change per unit time of the inner pot temperature from positive. and a predetermined first set time before becomes negative, between the temperature change per unit time of the internal pot temperature is the predetermined second set time after becoming from positive to negative, among the temperature detecting means detects A temperature information acquisition means for acquiring temperature information based on the kettle temperature, and a temperature condition storage means for preliminarily storing temperature conditions for determining normal rice cooking in relation to the inner kettle temperature from the first set time to the second set time. Based on the temperature information acquired by the temperature information acquisition means and the temperature condition stored in the temperature condition storage means, it is determined whether or not the rice is cooked normally, and if it is determined that the rice is cooked normally, the cooking process is started. When the transition temperature of the cooking process to be transferred is set to the first temperature and it is determined that the rice is not normally cooked, the cooking process transition setting means for setting the transition temperature of the cooking process to the second temperature higher than that of the normal rice cooking is used. characterized in that it comprises.

According to the present invention, since the control means includes the time measuring means, the temperature information acquiring means, the temperature condition storage means, and the cooking process transition setting means as described above, it is normal in the main cooking process based on the inner pot temperature. It can be determined whether or not the rice is cooked, and if it is determined that the rice is not cooked normally, the transition temperature to the cooking process is set to the second temperature higher than the first temperature in the case of normal rice cooking, and the rice is cooked at an early stage. It is possible to suppress the switching of the thermal power to the increased thermal power. Therefore, it is possible to suppress the occurrence of a problem of insufficient cooking. Therefore, even when the rice is cooked by putting the rice cooking net inside the inner pot, it is possible to accurately shift from the main cooking process to the cooking process and cook the rice with the desired taste.

In the present invention, the temperature information acquired by the temperature information acquisition means is the temperature change per unit time, and the temperature condition stored in advance by the temperature condition storage means is that the temperature change per unit time is zero or less. Is desirable. Generally, in the case of normal rice cooking, the temperature of the inner pot rises to a peak temperature during the main cooking process and then drops once, and the temperature change per unit time changes from positive to negative. That is, in the main cooking process of normal rice cooking, the temperature gradient changes from positive to negative in the inner pot temperature. Therefore, it is stored in advance in the temperature condition storage means that the temperature change per unit time in the case of normal rice cooking is zero or less. As a result, the cooking process transition setting means reliably determines whether or not the rice is cooked normally based on whether or not the temperature change per unit time acquired by the temperature information acquisition means is zero or less in the main cooking process. It can be carried out.

In the present invention, the temperature information that the temperature information acquisition means acquires are internal pot temperature, and the temperature condition that the temperature condition storing means stores in advance state, and are more than a predetermined threshold value of the inner pot temperature, this threshold temperature der Rukoto inflection near point a temperature change per unit time of the internal pot temperature is from positive to negative is desired. The temperature of the inner pot from the first set time to the second set time in the main cooking process when the rice is not normally cooked is lower than the temperature of the inner pot in the case of normal rice cooking. Therefore, the cooking process is performed by storing in advance in the temperature condition storage means that the temperature change of the inner pot temperature per unit time is equal to or higher than a predetermined threshold value, which is the temperature near the inflection point from positive to negative. In the main cooking step, the transition setting means can reliably determine whether or not the rice is normally cooked depending on whether or not the temperature of the inner pot acquired by the temperature information acquisition means is equal to or higher than a predetermined threshold value.

The cross-sectional view which shows one Embodiment of the rice cooker of this invention. The graph which shows the change of the inner pot temperature in the case of normal rice cooking by the rice cooker shown in FIG. A graph showing changes in the temperature of the inner pot when rice is not cooked normally in a conventional rice cooker. FIG. 3 is a block diagram of a control means provided in the rice cooker shown in FIG. 1 and its peripheral means. The flowchart which shows the control method of the control means shown in FIG.

As shown in FIG. 1, the rice cooker 1 according to the embodiment of the present invention has an inner pot 2 that opens upward and allows rice and water to enter inside, and an inner pot 2 that can be internally stored, and the inner pot 2 can be stored. It has a main body 4 having a lid 3 covering from above, a temperature detecting means 5 for detecting the temperature of the inner pot 2, a heating means 6 for heating the inner pot 2, and a control means 7 for controlling heating by the heating means 6. There is. The rice cooker 1 executes rice cooking in the order of a pre-cooking step, a main cooking step, a cooking step, and a steaming step.

The inner pot 2 has a plurality of legs 21 extending downward on the outer periphery of the outer bottom surface, and a support portion 22 extending downward in the center of the outer bottom surface. The main body 4 has a first storage space 41 for accommodating the inner pot 2 on the upper side, and a second storage space 42 for accommodating the temperature detecting means 5, the heating means 6, and the control means 7 on the lower side. The first storage space 41 and the second storage space 42 are separated and partitioned by a partition plate 43. The upper ends of the temperature detecting means 5 and the heating means 6 housed in the second storage space 42 project from the partition plate 43 toward the inside of the first storage space 41. Further, the temperature detecting means 5 is in contact with the lower end of the support portion 22 of the inner pot 2. Therefore, the temperature detecting means 5 can detect the temperature of the inner pot. The heating means 6 is a burner, and the combustion flame heats the inner pot 2 toward the outer bottom surface of the inner pot 2. The control means 7 is housed in the bottom of the second storage space 42, which is not easily affected by heat from the heating means 6. Further, an operation unit 8 is provided on the outer wall portion of the main body 4 corresponding to the second storage space 42. The operation unit 8 is provided with various switches such as a power switch, a rice cooking menu switch, and a rice cooking switch.

Generally, in the rice cooker 1, as shown in FIG. 2, when a predetermined time t2 has elapsed from the start of rice cooking (for example, 14 minutes later), the inner pot temperature T1 is detected. Upon receiving this temperature detection, the control means 7 continues the main cooking process until the temperature of the inner pot reaches the cooking process transition temperature T2 (T2 = T1 + a ° C. (a is about 2 ° C.)). In the case of normal rice cooking, as shown in FIG. 2, in the main cooking process, the temperature of the inner pot once rises to a temperature higher than T1 by the predetermined time t2, but then falls, and per unit time. The temperature change ΔT of is changed from positive to negative. That is, in the main cooking process of normal rice cooking, the temperature gradient changes from positive to negative in the inner pot temperature. On the other hand, when the rice cooking net is put inside the inner pot 2 to cook rice, the temperature gradient of the inner pot temperature up to the predetermined time t2 is always positive as shown in FIG. Therefore, the inner pot temperature reaches the cooking process transition temperature T2 shortly after the predetermined time t2 has elapsed. Therefore, as compared with normal rice cooking, when the rice cooking net is put inside the inner pot 2 to cook rice, the time required for the main cooking process is shorter than that of normal rice cooking. As a result, the rice cooking state at the time of transition to the cooking process is different from the rice cooking state of normal rice cooking in which water is almost exhausted in the inner pot 2, and water still remains. This is a problem of insufficient cooking.

Further, when a rice cooking net is put inside the inner pot 2 to cook rice, the temperature gradient is always positive as shown in FIG. 3, but the temperature of the inner pot reaches a temperature reached by normal rice cooking by a predetermined time t2. Not reachable. For this reason, the heat input to the rice and water is not sufficient, and the rice cooking state at the time of transition to the cooking process is different from the rice cooking state of normal rice cooking in which there is almost no water in the inner pot, and water still remains. It becomes a state of cooking, and a problem of insufficient cooking occurs.

Therefore, in the rice cooker 1, improvements have been made to the configuration and control method of the control means 7 shown in FIG. That is, as shown in FIG. 4, the control means 7 includes a time measuring means 71, a temperature information acquiring means 72, a temperature condition storage means 73, and a cooking process transition setting means 74. The time measuring means 71 measures the time from the start of rice cooking, and the measured time is input to the temperature information acquisition means 72 and the cooking process transition setting means 74. As shown in FIGS. 2 and 3, the temperature information acquisition means 72 detects the temperature between the predetermined first set time t1 and the subsequent second set time t2 in the elapsed time from the start of rice cooking in the main cooking step. The temperature information based on the inner pot temperature detected by the means 5 is acquired. Here, the second set time t2 is the same time as the above-mentioned predetermined time t2, and the first set time t1 is shorter than the second set time t2. The first set time t1 and the second set time t2 are parameters that can be appropriately changed depending on the use, capacity, etc. of the rice cooker 1 and the basic rice cooking control method in each process, and are determined based on empirical values. can do. Further, in the basic rice cooking control method, the main cooking process may be composed of a plurality of stages. In this case, the second set time t2 is the elapsed time from the start of rice cooking to immediately before the final stage of the main cooking process. Can be. In a broad sense, based on the change in the inner pot temperature in the case of normal rice cooking as described above, the temperature gradients of the first set time t1 and the second set time t2 are positive to negative in the inner pot temperature, respectively. It can be exemplified as a predetermined time before the change appears, and a predetermined time after the change in the temperature gradient from positive to negative appears in the inner pot temperature. Specifically, 8 minutes is exemplified for the first set time t1, and 14 minutes is exemplified for the second set time.

The temperature condition storage means 73 stores in advance the temperature conditions for determining normal rice cooking in relation to the inner pot temperature from the first set time t1 to the second set time t2 in the case of normal rice cooking. The cooking process transition setting means 74 determines whether or not the rice is normally cooked based on the temperature information acquired by the temperature information acquisition means 72 and the temperature conditions stored in the temperature condition storage means 73. Further, when the cooking process transition setting means 74 determines that the rice is normally cooked, the cooking process transition temperature T2 for shifting to the cooking process is set to the first temperature. On the other hand, when the cooking process transition setting means 74 determines that the rice is not normally cooked, the cooking process transition temperature (first temperature) T2 is set to a second temperature T21 higher than that of the normal cooked rice. Here, the cooking process transition temperature T2 is set in the cooking process transition setting means 74 based on the detection temperature T1 of the second set time t2, similarly to the cooking process transition temperature T2 shown in FIGS. 2 and 3. be able to. That is, T2 = T1 + a ° C. (a is about 2 ° C.) is exemplified. The second temperature T21 when it is determined that the rice is not normally cooked can be set in the cooking process transition setting means 74 as T21 = T1 + b ° C. It is desirable that the value of b is larger than the value of a, and for example, about 4 ° C to 5 ° C is exemplified.

The temperature information acquired by the temperature information acquisition means 72 may be stored by the temperature information acquisition means 72 itself, or the control means 7 may be provided with a separate storage means and the storage means may store the temperature information. When the storage means is separately provided, the cooking process transition setting means 74 makes it possible to access the storage means. Similarly, the inner pot temperature detected by the temperature detecting means 5 may be stored by the temperature information acquiring means 72 or may be stored separately in the control means 7 by the storage means. In the latter case, the case of the latter case. The cooking process transition setting means 74 also makes it possible to access the storage means.

The above control means 7 can be realized by, for example, a microcomputer or the like. Further, the control means 7 can be electrically connected to the power supply circuit 9 to supply electric power from the power supply circuit 9 to the control means 7. The temperature detecting means 5, the heating means 6, and the operating unit 8 can also be electrically connected to the control means 7.

The temperature information acquired by the temperature information acquisition means 72 is, for example, the temperature per unit time between the predetermined first set time t1 and the subsequent second set time t2 in the elapsed time from the start of rice cooking in the main cooking step. It can be the change ΔT. In this case, the temperature condition stored in advance by the temperature condition storage means 73 is the temperature change ΔT per unit time in the case of normal rice cooking, that is, ΔT ≦ 0. Further, the temperature information acquired by the temperature information acquisition means 72 can be, for example, the temperature of the inner pot detected by the temperature detection means 5, and in this case, the temperature condition stored in advance by the temperature condition storage means 73 may be. It is equal to or higher than a predetermined threshold Tx of the inner pot temperature. The threshold value Tx can be determined based on the inner pot temperature that reaches from the first set time t1 to the second set time t2 shown in FIG. For example, the temperature change ΔT per unit time, that is, the temperature near the inflection point where the temperature gradient changes from positive to negative can be exemplified as the threshold value Tx. Specifically, the threshold value Tx can be a temperature in the range from the temperature at which the temperature change ΔT per unit time becomes zero to a temperature within about 1 ° C. to 3 ° C. lower than this temperature.

The rice cooking control by the control means 7 as described above is executed according to, for example, the flowchart shown in FIG. In the operation unit 8 of the rice cooker 1 shown in FIG. 1, for example, when the power switch is turned on, the rice cooking menu is selected and the rice cooker switch is turned on, the main valve opens when the rice cooker 1 is, for example, a gas cooker. At the same time that the proportional valve is adjusted to an appropriate opening degree, a voltage is applied to the igniter to ignite and start cooking rice (step S1). At this time, the time measuring means 71 shown in FIG. 4 is activated, and the time measurement is started. Then, the pre-cooking step is started (step S2). After that, when the conditions for shifting to the main cooking process, for example, predetermined conditions regarding the elapsed time and temperature are satisfied, the process shifts to the main cooking process (step S3). The basic control method of shifting from the pre-cooking process to the main-cooking process can, for example, follow the conventional control method. Then, when the first set time t1 elapses (step S4), acquisition of the temperature change ΔT per unit time is started (step S5). As a unit of ΔT, for example, ° C./sec is exemplified. The acquisition of ΔT is performed by the temperature information acquisition means 72 shown in FIG. The temperature information acquisition means 72 calculates and acquires the temperature change ΔT per unit time based on the time input from the time measuring means 71 and the inner pot temperature input from the temperature detecting means 5. The calculated temperature change ΔT per unit time can be stored in the temperature information acquisition means 72 or the storage means as described above.

Next, the cooking process transition setting means 74 shown in FIG. 4 determines whether or not the rice is normally cooked based on the temperature information acquired by the temperature information acquisition means 72 (step S6). There are two types of normal rice cooking determination methods performed by the cooking process transition setting means 74. One is based on the value of the temperature change ΔT per unit time, and the other is based on the temperature of the inner pot. In the former, it is determined whether or not the rice is normally cooked based on ΔT ≦ 0 stored in the temperature condition storage means 73. The determination in this case is made based on whether or not ΔT ≦ 0 is detected three times in succession every 10 seconds, and when ΔT ≦ 0 is detected three times in succession every 10 seconds, the cooking process shifts. The setting means 74 determines that the rice is normally cooked. In the latter, it is determined whether or not the rice is normally cooked based on the threshold value Tx or more stored in the temperature condition storage means 73. The determination in this case is performed based on whether or not the temperature of the inner pot is equal to or higher than the threshold value Tx, and when it is detected that the temperature reaches the threshold value Tx, the cooking process transition setting means 74 determines that the rice is cooked normally. The determination made by the cooking process transition setting means 74 is continuously performed until the second set time t2. When it cannot be determined that the cooked rice is normally cooked by the second set time t2, the cooking process transition setting means 74 determines that the cooked rice is not normally cooked. In any of the determination methods, when it is determined that the rice is cooked normally, the inner pot temperature T1 at that time is stored after the second set time t2 elapses (steps S7 and S8). The inner pot temperature T1 can be stored by the temperature information acquisition means 72 or the storage means as described above. Then, the cooking process transition setting means 74 sets the cooking process transition temperature T2 as the first temperature based on the inner pot temperature T1. That is, T2 = T1 + a ° C. (a is about 2 ° C.) is set. When the cooking process transition temperature T2 is reached (step S9), the opening degree of the proportional valve is changed in the heating means 6, and the heating power becomes “weak” (step S10). Then, the process proceeds to the cooking process (step 11).

On the other hand, when it is determined in step S6 that the cooking process transition setting means 74 is not normal rice cooking, after the second set time t2 elapses (step S12), the inner pot temperature T1 at that time is set to the temperature information acquisition means 72 or the storage means. (Step S13), the cooking process transition setting means 74 sets the cooking process transition temperature T2 to the second temperature T21, which is higher than that at the time of normal rice cooking (step S14). That is, the second temperature T21 is set to T21 = T1 + b ° C. (b> a, where b is about 4 ° C. to 5 ° C.) as described above. When the second temperature T21 is reached (step S15), the control method is the same as that of step S10.

After shifting to the cooking process, it is the same as the conventional control method. When the cooking step is completed, the heating means 6 stops heating and extinguishes the fire (step S16). After this, the process proceeds to the steaming process (step 17), and the rice cooking is completed.

For example, by controlling the rice cooking by the control means 7 as described above, it is possible to determine whether or not the rice is cooked normally based on the temperature of the inner pot in the main cooking process. By setting T2 to the second temperature T21, which is higher than the first temperature in the case of normal rice cooking, it is possible to suppress the switching of the heating power to the cooking heating power at an early stage. Therefore, it is possible to suppress the occurrence of a problem of insufficient cooking. Therefore, even when the rice is cooked by putting the rice cooking net inside the inner pot, it is possible to accurately shift from the main cooking process to the cooking process and cook the rice with the desired taste.

In addition, it is possible to suppress the occurrence of the above-mentioned problem of insufficient cooking in the same way when cooking rice that is insufficiently washed. When cooking rice that has not been washed sufficiently, impurities and the like tend to accumulate in the inner bottom of the inner pot 2 shown in FIG. There is. It is determined that such a problem is not normal rice cooking because it is possible to determine whether or not the rice is normally cooked based on the temperature of the inner pot in the main cooking process by the rice cooking control shown in FIG. 5 by the control means 7 shown in FIG. Then, the transition temperature T2 to the cooking process can be set to the second temperature T21, which is higher than the first temperature in the case of normal rice cooking, and the switching of the heating power to the cooking heating power at an early stage can be suppressed. Even when cooking rice that has not been washed enough, the transition from the main cooking process to the cooking process can be performed accurately, and rice with the desired taste can be cooked.

Further, by storing in advance in the temperature condition storage means 73 that the temperature change ΔT per unit time in the case of normal rice cooking is zero or less, the cooking process transition setting means 74 can perform the temperature in the main cooking process. Whether or not the rice is normally cooked can be reliably determined based on whether or not the temperature change ΔT per unit time acquired by the information acquisition means 72 is zero or less.

Further, by storing in advance in the temperature condition storage means 73 that the inner pot temperature is equal to or higher than a predetermined threshold value Tx, the cooking process transition setting means 74 is acquired by the temperature information acquisition means 72 in the main cooking process. Whether or not the rice is normally cooked can be reliably determined based on whether or not the temperature of the inner pot is equal to or higher than a predetermined threshold value Tx.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the above embodiments. The present invention can be variously modified and implemented without departing from the spirit of the present invention.

1 ... rice cooker, 2 ... inner pot, 3 ... lid, 4 ... main body, 5 ... temperature detecting means, 6 ... heating means, 7 ... control means, 71 ... time measuring means, 72 ... temperature information acquiring means, 73 ... temperature Condition storage means, 74 ... Cooking process transition setting means, t1 ... First set time, t2 ... Second set time, T1 ... Inner pot temperature, T2 ... Cooking process transition temperature (first temperature), T21 ... Second Temperature, ΔT ... Temperature change per unit time, Tx ... Threshold.

Claims (3)

An inner pot that opens upward and allows rice and water to enter inside, a main body that can store the inner pot inside and has a lid that covers the inner pot from above, a temperature detecting means that detects the temperature of the inner pot, and the inside. In a rice cooker that has a heating means for heating a kettle and a control means for controlling heating by the heating means, and executes rice cooking in the order of a pre-cooking step, a main cooking step, a cooking step, and a steaming step.
The control means are a time measuring means for measuring the time from the start of rice cooking, and a predetermined number of times elapsed from the start of rice cooking in the main cooking process before the temperature change per unit time of the inner pot temperature changes from positive to negative . Acquires temperature information based on the inner pot temperature detected by the temperature detecting means between one set time and a predetermined second set time after the temperature change per unit time of the inner pot temperature changes from positive to negative. The temperature information acquisition means, the temperature condition storage means that stores in advance the temperature conditions that are determined to be normal rice cooking in relation to the inner pot temperature from the first set time to the second set time, and the temperature information acquisition means acquire. Based on the temperature information and the temperature condition stored in the temperature condition storage means, it is determined whether or not the rice is normally cooked, and if it is determined that the rice is normally cooked, the temperature at which the cooking process is transferred to the cooking process is determined. When the temperature is set to the first temperature and it is determined that the rice is not normally cooked, the cooking process transition setting means for setting the cooking process transition temperature to a second temperature higher than the normal rice cooking is provided. rice cooker. The temperature information acquired by the temperature information acquisition means is the temperature change per unit time, and the temperature condition stored in advance by the temperature condition storage means is characterized in that the temperature change per unit time is zero or less. The rice cooker according to claim 1. Temperature information temperature information acquisition means acquires are internal pot temperature, and the temperature condition that the temperature condition storing means stores in advance state, and are more than a predetermined threshold value of the inner pot temperature, this threshold, the inner pot temperature cooker according to claim 1, wherein the unit temperature change per time is characterized temperatures der Rukoto near the inflection point, which is a positive to a negative.

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