JP6141081B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker that performs a rice cooking operation by determining the amount of rice cooked in the inner pot before induction heating the inner pot.

  As a conventional rice cooker, a convex heating coil that heats a convex bottom part that protrudes inwardly at the center of the bottom of the inner pot, a bottom heating coil that heats the surrounding bottom part excluding the convex bottom part of the inner pot, The convex temperature sensor that detects the temperature of the convex bottom of the kettle, the bottom temperature sensor that detects the temperature of the bottom of the inner kettle, and the convex heating coil and the bottom heating coil at the same time or alternately according to the detected temperature of each temperature sensor (For example, refer to Patent Document 1).

JP 2001-161549 A (page 2-3, FIG. 1)

  However, in the conventional rice cooker described above, when a small or medium amount of cooked rice is cooked, the convex bottom portion of the inner pot is exposed higher than the height of the cooked rice (rice and water). In such a case, it is difficult to determine the amount of rice cooked in a small amount or a medium amount only by the detection temperature of the convex temperature sensor near the convex heating coil and the bottom temperature sensor near the bottom heating coil, and optimal control according to the amount of rice cooking However, it is not possible to start cooking rice, and there is a possibility that power supply is insufficient or excessive power is supplied.

  When the optimum amount of rice cooking cannot be determined and when the heating is actively performed with the convex heating coil to reduce temperature unevenness from the preheating process, the convex bottom of the inner pot is baked and heat loss occurs, resulting in energy saving. There is also a problem from the viewpoint. Further, there is a concern that the temperature of the convex bottom portion of the inner hook becomes unnecessarily high, and the deterioration of the durability of the main body such as the inner hook is accelerated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rice cooker that can suppress a heating loss and an unnecessary temperature rise in the convex housing portion of the inner pot.

The rice cooker according to the present invention is provided with an opening in the upper part of the main body, an intermediate container having a convex portion extending from the bottom to the opening side in a hollow state at the center of the bottom part, and is detachably accommodated in the intermediate container. An inner hook having a convex accommodating portion into which the convex portion of the middle container is inserted at the center of the bottom, a lid provided on the main body for opening and closing the opening of the middle container, and an inner peripheral upper portion of the convex portion of the middle container A convex heating coil, a bottom heating coil provided at the bottom of the inner container, a bottom temperature sensor for detecting the bottom temperature of the inner pot, a side temperature sensor for detecting the side temperature of the inner pot, and the inside of the inner pot An internal temperature sensor for detecting the temperature, and a control means for controlling the energization to the bottom heating coil and the convex heating coil to inductively heat the inner pot. Setting bottom temperature for rice cooking amount judgment according to temperature, setting side Includes a table in which the temperature, setting the internal temperature is set respectively, bottom temperature before induction heating of the inner hook, loading side temperature and internal temperature, again by induction heating the internal pot after a predetermined time has elapsed, the bottom temperature , Read the side temperature and internal temperature, calculate the temperature change values for the bottom temperature, side temperature and internal temperature before induction heating the inner pot , and then read the internal temperature before induction heating the inner pot The set bottom temperature, the set side surface temperature, and the set internal temperature set as the temperature are extracted from the table, compared with each temperature change value, and the amount of cooked rice in the inner pot is determined from the comparison result .

  In the present invention, the bottom temperature, the side surface temperature, and the internal temperature are read before the inner pot is induction-heated, and after a predetermined time has elapsed after the inner pot is induction-heated, the bottom temperature, the side surface temperature, and the internal temperature are read. The temperature change values are calculated based on the bottom temperature, the side surface temperature, and the internal temperature before induction heating the kettle, and the amount of cooked rice in the inner kettle is determined from each temperature change value. As a result, even if the cooked rice is lower than the height of the convex housing part provided in the center of the bottom of the inner pot, the amount of rice cooked in the inner pot can be accurately determined. It is possible to supply optimal power without performing a sufficient power supply. Moreover, a heating loss and an unnecessary temperature rise in the convex housing portion of the inner hook can be suppressed, so that a decrease in durability of the main body such as the inner hook can be suppressed.

The longitudinal cross-sectional view which shows schematic structure of the rice cooker which concerns on Embodiment 1 of this invention. The flowchart which shows operation | movement of the rice cooker which concerns on Embodiment 1 of this invention. The longitudinal cross-sectional view which shows schematic structure of the rice cooker which concerns on Embodiment 2 of this invention. The flowchart which shows operation | movement of the rice cooker which concerns on Embodiment 2 of this invention. The longitudinal cross-sectional view which shows schematic structure of the rice cooker which concerns on Embodiment 3 of this invention. The flowchart which shows operation | movement of the rice cooker which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
1 is a longitudinal sectional view showing a schematic configuration of a rice cooker according to Embodiment 1 of the present invention.
In FIG. 1, the rice cooker includes a main body 1 having a middle container 6 with an opening in the upper part, an inner pot 2 that is detachably accommodated in the middle container 6 of the main body 1, and And a lid 3 that opens and closes the opening. At the center of the bottom of the middle container 6 is provided a substantially cylindrical convex portion 6a extending from the bottom to the opening side in a hollow state.

  As the material of the inner pot 2, a magnetic metal material, a clad of a magnetic metal material and a non-magnetic highly conductive metal material, a non-magnetic material having a high electric resistance, such as a carbon material, is used. In the center of the bottom of the inner hook 2, a substantially cylindrical convex receiving portion 2a into which the convex portion 6a of the inner container 6 is inserted is provided. The height of the convex accommodating portion 2a is substantially the same as the scale indicating the most amount of cooked rice in the inner pot 2. In addition, about the convex part of the shape of an inner hook, if the objective of enlarging a heating area especially in the perpendicular direction is achieved, it may be cylindrical or chevron.

  The main body 1 detects the convex portion heating coil 4 provided on the inner peripheral upper part of the convex portion 6 a of the middle container 6, the bottom portion heating coil 5 provided on the bottom portion of the middle container 6, and the bottom temperature of the inner pot 2. A bottom temperature sensor 7, a side surface temperature sensor 8 that detects the side surface temperature of the inner pot 2, and a lid temperature sensor that detects the internal temperature of the inner pot 2 provided on the opening side surface of the inner container 6 of the lid 3. 9 (internal temperature sensor), and a control device 10 that controls energization to the bottom heating coil 5 and the convex heating coil 4 to inductively heat the inner pot 2.

  For the bottom temperature sensor 7, the side surface temperature sensor 8, and the lid temperature sensor 9, for example, a thermistor is used. The bottom heating coil 5 is wound up to the height of the scale indicating the minimum amount of rice cooking in the inner pot 2. The side surface temperature sensor 8 is installed at the height of a scale indicating a medium amount of cooked rice. In addition, although the convex part heating coil 4 and the bottom part heating coil 5 are used as a heating means, it replaces with this and the sheathed heater is provided in the inner peripheral upper part of the convex part 6a of the middle container 6, and the bottom part of the middle container 6 Then, the inner pot 2 may be heated.

  The control device 10 reads the bottom temperature, the side surface temperature, and the internal temperature when starting rice cooking, that is, before induction heating the inner pot 2. Next, the control device 10 reads the bottom temperature, the side surface temperature, and the internal temperature again after a lapse of a certain period of time after induction heating the inner pot 2, and the bottom temperature, the side surface temperature, and the internal temperature before the inner pot 2 is induction heated. Each temperature change value is calculated from the temperature, and the amount of cooked rice in the inner pot 2 is determined from each temperature change value.

  Specifically, the control device 10 is a table (not shown) in which a set bottom temperature, a set side surface temperature, and a set internal temperature for rice cooking amount determination are set in advance according to the internal temperature before the inner pot 2 is induction-heated. The set bottom temperature, the set side surface temperature and the set internal temperature set to the internal temperature read before the inner pot 2 is induction-heated are extracted from the table. Then, the control device 10 compares the extracted set bottom temperature, set side surface temperature and set internal temperature with each temperature change value, and calculates the amount of rice cooked in the inner pot 2 from the comparison result (the magnitude of the temperature of each part). judge. Then, the control apparatus 10 implements each process of a preheating process, a cooking process, a boiling maintenance process, and the unevenness process according to the determined rice cooking amount.

  The control device 10 may be configured by hardware such as a circuit device that realizes the above functions, or may be configured by an arithmetic device such as a microcomputer or a CPU and software executed on the arithmetic device. Also good.

Next, the rice cooking operation of the rice cooker according to the first embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing the rice cooking operation of the rice cooker according to Embodiment 1 of the present invention.
Put the inner pot 2 containing cooked rice (water and rice) in the middle container 6 of the main body 1, close the lid 3, and turn on the rice cooking switch (not shown) provided on the lid 3. Then, the control apparatus 10 starts cooking rice (S1).

  At this time, the control device 10 does not inductively heat the inner pot 2, and the bottom temperature of the inner pot 2 detected by the bottom temperature sensor 7, the side temperature of the inner pot 2 detected by the side temperature sensor 8, and the lid Each temperature of the internal temperature of the inner pot 2 detected by the temperature sensor 9 is read and stored as the bottom initial temperature Tb0, the side surface initial temperature Ts0, and the internal initial temperature Ti0 at the start of rice cooking t0 (S2). Next, the control device 10 controls each inverter circuit (not shown) so that a high-frequency current flows through the convex heating coil 4 and the bottom heating coil 5 (S3), and induction heats the inner pot 2.

  The control device 10 detects the bottom of the inner pot 2 detected by the bottom temperature sensor 7 when a predetermined time t (for example, several seconds) has elapsed since the energization start of the convex heating coil 4 and the bottom heating coil 5 (S4). The temperature Tb, the side surface temperature Ts of the inner pot 2 detected by the side surface temperature sensor 8, and the inner temperature Ti of the inner pot 2 detected by the lid temperature sensor 9 are read (S5).

  And the control apparatus 10 subtracts each temperature Tb0, Ts0, Ti0 at the time of rice cooking start t0 from each temperature Tb, Ts, Ti at the time of fixed time t progress, and calculates each temperature change value (S6). That is, the controller 10 subtracts the bottom initial temperature Tb0 from the bottom temperature Tb to obtain the bottom temperature change value ΔTb, subtracts the side face initial temperature Ts0 from the side face temperature Ts to obtain the side face temperature change value ΔTs, and the internal temperature Ti. The internal initial temperature Ti0 is subtracted from the internal temperature change value ΔTi.

  Thereafter, the control device 10 extracts the set bottom temperature ΔTbj, the set side surface temperature ΔTsj, and the set internal temperature ΔTij for determining the amount of cooking rice set according to the internal initial temperature Ti0 at the start of rice cooking t0 from the table (S7). . This is the ambient environment at the start of rice cooking, for example, the temperature, the temperature after cooking once, and the internal initial temperature Ti0 differs depending on the temperature in the main body 1 immediately after the heat retention, A set bottom temperature ΔTbj, a set side surface temperature ΔTsj, and a set internal temperature ΔTij for rice cooking amount determination according to the internal initial temperature Ti0 are extracted.

  Then, the control device 10 determines whether or not ΔTb <ΔTbj and ΔTs <ΔTsj (S8). This is a method of determining the amount of cooked rice by the rapid temperature rise caused by the baked state, which occurs because the cooked rice in the inner pot 2 does not enter the predetermined height. When ΔTb> ΔTbj and ΔTs ≧ ΔTsj, the controller 10 determines that the amount of rice cooked in the inner pot 2 is “small” and proceeds to S20. However, when ΔTb <ΔTbj and ΔTs <ΔTsj, ΔTi It is determined whether <ΔTij (S9).

  In S9, when ΔTi <ΔTij, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “large” and continues energizing the convex heating coil 4 and the bottom heating coil 5 (S10). Then, the preheating process, the cooking process, the boiling maintenance process, and the uneven process are sequentially performed (S11 to S14), and the rice cooking is completed when the uneven process is completed (S25).

  In the preheating process, the control device 10 controls energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheating temperature. When the preheating temperature is reached, the energization to the convex heating coil 4 and the bottom heating coil 5 is controlled so that the state is maintained. In the cooking process, the control device 10 controls the energization of the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice rises to 98 ° C. (temperature at which the rice is made into α).

  Furthermore, in the boiling maintenance process, the control device 10 controls the energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice reaches the boiling temperature, and the rice is turned into α in this state. Keep boiling until. In the unevenness process, the control device 10 stops energization of the convex heating coil 4 and the bottom heating coil 5 and unevenly cooks the cooked rice (rice cooked rice) until the uneven time corresponding to the amount of rice cooked. In each step, the convex heating coil 4 and the bottom heating coil 5 are alternately energized so that natural convection occurs from the central portion of the inner pot, and from the inner peripheral side surface of the inner pot 2. Natural convection may be caused, temperature unevenness in the inner pot 2 is reduced, and cooked rice may be cooked evenly.

  In S9, when ΔTi ≧ ΔTij, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “medium”, stops energization of the convex heating coil 4, and energizes only the bottom heating coil 5. Continue (S15) and, as described above, perform the preheating step, the cooking step, the boiling maintenance step, and the unevenness step in order (S16 to S19), and finish the cooking when the unevenness step is completed. (S25).

  In the preheating process, the control device 10 controls energization to the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheat temperature, and the convex housing portion 2a exposed from the cooked rice. The energization to the convex heating coil 4 is performed for a short time so that the temperature does not become abnormal. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible.

  In the cooking process and the boiling maintenance process, the control device 10 is configured so that the energization time to the convex heating coil 4 is gradually longer than that in the preheating process when the rice sucks water to some extent and the volume increases. To. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot, and the inner pot 2 Natural convection occurs from the inner peripheral side of the rice bowl so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

  Further, in S8, when ΔTb <ΔTbj and ΔTs ≧ ΔTsj in S8, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “small amount”, stops energization of the convex heating coil 4, Only the bottom heating coil 5 is energized (S20), and as described above, the preheating process, the cooking process, the boiling maintenance process, and the uneven process are performed in order (S21 to S24), and the uneven process is performed. When finished, the cooking is finished (S25).

  In the preheating process, the control device 10 energizes only the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 becomes the preheating temperature. In the cooking process / boiling maintenance process, the control device 10 absorbs water to some extent and increases the volume so that the convex housing part 2a exposed from the cooked rice does not reach an abnormal temperature. The energization to the convex heating coil 4 is performed for a short time. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot 2, and the inner pot The natural convection is caused from the inner peripheral side surface of 2 so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

As described above, according to the first embodiment, at the time of starting rice cooking (before induction heating of the inner pot 2), the bottom initial temperature Tb0, the side surface initial temperature Ts0, and the internal initial temperature Ti0 are read, and the inner pot 2 is After a certain time t has elapsed after induction heating, the bottom temperature Tb, the side surface temperature Ts and the internal temperature Ti are read, and the bottom initial temperature Tb0, the side surface initial temperature Ts0 and the internal initial temperature Ti0 before induction heating the inner pot 2 To calculate the temperature change values ΔTb, ΔTs, and ΔTi, respectively. Then, the set bottom temperature ΔTbj, the set side surface temperature ΔTsj and the set internal temperature ΔTij set corresponding to the internal initial temperature Ti0 (internal temperature Ti0) read before the inner pot 2 is induction-heated are extracted from the table, Each temperature change value ΔTb, ΔTs, ΔTi is compared, and the amount of cooked rice in the inner pot 2 is determined from the comparison result.
Thereby, when the cooked rice is lower than the height of the convex housing part 2a provided at the bottom center of the inner pot 2, that is, even if the amount of cooked rice is small or medium, the amount of cooked rice in the inner pot 2 can be accurately determined. Can be judged. For this reason, there is no shortage of power supply or excessive power supply, and optimal power can be supplied. Moreover, a heating loss and an unnecessary temperature rise of the convex housing portion 2a of the inner hook 2 can be suppressed, and therefore a decrease in durability of the main body 1 such as the inner hook 2 can be suppressed.

Embodiment 2. FIG.
FIG. 3 is a longitudinal sectional view showing a schematic configuration of the rice cooker according to Embodiment 2 of the present invention.
As shown in FIG. 3, the rice cooker according to Embodiment 2 includes an inner pot 2 and a weight sensor 11 that detects the weight of the cooked food in the inner pot 2 immediately below the inner pot 2. The side surface temperature sensor 8 used as one of the purposes for detecting this is omitted. Other components are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted.

  The control device 10 reads the bottom temperature and the internal temperature before induction heating the inner pot 2, reads the weight of the inner pot 2, and corrects the weight according to the read bottom temperature and the internal temperature. The amount of cooked rice in the inner pot 2 is determined based on the weight. Specifically, the control device 10 has a table (not shown) in which correction values are set in advance according to the bottom temperature and the internal temperature before the inner pot 2 is induction-heated. The correction value set to the bottom temperature and the internal temperature read before heating is selected from the table, the weight read before induction heating of the inner pot 2 is corrected, and the inside of the inner pot 2 is corrected based on the corrected weight. Determine the amount of rice cooked. Then, the control apparatus 10 implements each process of a preheating process, a cooking process, a boiling maintenance process, and the unevenness process according to the determined rice cooking amount.

Next, the rice cooking operation of the rice cooker according to Embodiment 2 will be described with reference to FIGS. FIG. 4 is a flowchart showing the operation of the rice cooker according to Embodiment 2 of the present invention.
Put the inner pot 2 containing cooked rice (water and rice) in the middle container 6 of the main body 1, close the lid 3, and turn on the rice cooking switch (not shown) provided on the lid 3. Then, the control apparatus 10 starts rice cooking (S31).

  At this time, the control device 10 does not inductively heat the inner pot 2, and the bottom temperature of the inner pot 2 detected by the bottom temperature sensor 7 and the inner pot 2 detected by the lid temperature sensor 9 (internal temperature sensor). Are read and stored as the bottom initial temperature Tb0 and the internal initial temperature Ti0 at the start of rice cooking t0 (S32). Next, the control device 10 reads the weight detected by the weight sensor 11, extracts the correction values set for the bottom initial temperature Tb0 and the internal initial temperature Ti0 from the table, and calculates the previously read weight as the correction value. And the amount of cooked rice in the inner pot 2 is selected based on the corrected weight (S33). The weight detected by the weight sensor 11 is the ambient environment at the start of rice cooking, for example, the air temperature, the temperature after cooking once, or the temperature in the main body 1 immediately after keeping warm, The correction values set for the bottom initial temperature Tb0 and the internal initial temperature Ti0 are extracted to correct the weight.

  Then, the control apparatus 10 determines whether the selected rice cooking amount is large (S34). This determination is made by comparing with a first threshold set in advance and a second threshold lower than the first threshold. For example, when the amount of cooked rice exceeds the first threshold, the amount is set to a large amount. When the amount of cooked rice is less than the first threshold and exceeds the second threshold, the amount is set to medium.

  When the amount of rice cooking is determined to be “large” by the above-described method, the control device 10 starts energizing the convex heating coil 4 and the bottom heating coil 5 (S35), the preheating process, the cooking process, and the boiling maintenance Each process of a process and a spotting process is implemented in order (S36-S39), and rice cooking is complete | finished when the spotting process is complete | finished (S51).

  In the preheating step, the control device 10 controls energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheating temperature, and the temperature of the cooked rice When the temperature reaches the preheating temperature, the energization to the convex heating coil 4 and the bottom heating coil 5 is controlled so that the state is maintained. In the cooking process, the control device 10 controls the energization of the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice rises to 98 ° C. (temperature at which the rice is made into α).

  Furthermore, in the boiling maintenance process, the control device 10 controls the energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice reaches the boiling temperature, and the rice is turned into α in this state. Keep boiling until. In the unevenness process, the control device 10 stops energization of the convex heating coil 4 and the bottom heating coil 5 and unevenly cooks the cooked rice (rice cooked rice) until the uneven time corresponding to the amount of rice cooked. In each step, the convex heating coil 4 and the bottom heating coil 5 are alternately energized so that natural convection occurs from the central portion of the inner pot, and from the inner peripheral side surface of the inner pot 2. Natural convection may be caused, temperature unevenness in the inner pot 2 is reduced, and cooked rice may be cooked evenly.

  When determining in S34 that the amount of cooked rice is not “large”, the control device 10 determines whether or not the amount of cooked rice is “medium” (S40). When the amount of cooked rice is determined to be “medium”, the control device 10 starts energizing only the bottom heating coil 5 (S41), and as described above, the preheating step, the cooking step, the boiling maintenance step, and the unevenness step. The steps are performed in order (S42 to S45), and the rice cooking is finished when the unevenness step is finished (S51).

  In the preheating process, the control device 10 controls energization to the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheat temperature, and the convex housing portion 2a exposed from the cooked rice. The energization to the convex heating coil 4 is performed for a short time so that the temperature does not become abnormal. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible.

  In the cooking process and the boiling maintenance process, the control device 10 is configured so that the energization time to the convex heating coil 4 is gradually longer than that in the preheating process when the rice sucks water to some extent and the volume increases. To. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot 2, and the inner pot The natural convection is caused from the inner peripheral side surface of 2 so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

  When it is determined that the amount of cooked rice is “small” in S40, the control device 10 starts energizing only the bottom heating coil 5 (S46), and as described above, the preheating step, the cooking step, the boiling maintaining step, and the unevenness. Each step of the step is performed in order (S47 to S50), and the rice cooking is finished when the unevenness step is finished (S51).

  In the preheating process, the control device 10 energizes only the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 becomes the preheating temperature. In the cooking process / boiling maintenance process, the control device 10 absorbs water to some extent and increases the volume so that the convex housing part 2a exposed from the cooked rice does not reach an abnormal temperature. The energization to the convex heating coil 4 is performed for a short time. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot 2, and the inner pot The natural convection is caused from the inner peripheral side surface of 2 so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

As described above, according to the second embodiment, at the time of starting rice cooking (before induction heating of the inner pot 2), the bottom initial temperature Tb0 and the internal initial temperature Ti0 are read and the weight of the inner pot 2 is read. The correction values set for the read bottom initial temperature Tb0 and the internal initial temperature Ti0 are selected from the table, the read weight is corrected before the inner pot 2 is induction-heated, and the inner pot 2 is corrected based on the corrected weight. The amount of cooked rice is judged.
Thereby, even when the cooked rice is lower than the height of the convex housing portion 2a provided at the center of the bottom of the inner pot 2, that is, even if the amount of cooked rice is small or medium, it is accurate without being affected by the ambient temperature. In addition, the amount of cooked rice in the inner pot 2 can be determined. For this reason, there is no shortage of power supply or excessive power supply, and optimal power can be supplied. Moreover, a heating loss and an unnecessary temperature rise of the convex housing portion 2a of the inner hook 2 can be suppressed, and therefore a decrease in durability of the main body 1 such as the inner hook 2 can be suppressed.

Embodiment 3 FIG.
FIG. 5 is a longitudinal sectional view showing a schematic configuration of a rice cooker according to Embodiment 3 of the present invention.
As shown in FIG. 5, the rice cooker according to Embodiment 3 includes a non-contact temperature sensor 12 that detects the upper surface temperature of the convex housing portion 2 a of the inner pot 2 on the back surface of the lid 3. Yes. Other components are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted. Although the non-contact temperature sensor 12 is provided on the back surface of the lid 3, the non-contact type temperature sensor 12 may not be provided on the lid 3 as long as the upper surface temperature of the convex housing portion 2 a of the inner hook 2 can be detected.

  The control device 10 reads the bottom temperature, the side surface temperature, and the top surface temperature when starting rice cooking, that is, before the inner pot 2 is induction heated, and after a certain time has elapsed after the inner pot 2 is induction heated, Read the temperature and top surface temperature, calculate each temperature change value with bottom temperature, side surface temperature and top surface temperature before induction heating the inner pot 2, and determine the amount of rice cooking in the inner pot 2 from each temperature change value To do.

  Specifically, the control device 10 is a table (not shown) in which a set bottom temperature, a set side surface temperature, and a set top surface temperature for rice cooking amount determination are set in advance according to the internal temperature before induction heating the inner pot 2. And a set bottom temperature, a set side surface temperature and a set top surface temperature corresponding to the internal temperature read before induction heating the inner pot 2 is extracted from the table and compared with each temperature change value, The amount of cooked rice in the inner pot 2 is determined from the comparison result. Then, the control apparatus 10 implements each process of a preheating process, a cooking process, a boiling maintenance process, and the unevenness process according to the determined rice cooking amount.

Next, the rice cooking operation of the rice cooker according to Embodiment 3 will be described with reference to FIGS. FIG. 6 is a flowchart showing the operation of the rice cooker according to Embodiment 3 of the present invention.
Put the inner pot 2 containing cooked rice (water and rice) in the middle container 6 of the main body 1, close the lid 3, and turn on the rice cooking switch (not shown) provided on the lid 3. Then, the control apparatus 10 starts cooking rice (S61).

  At this time, the control device 10 does not inductively heat the inner pot 2, the bottom temperature of the inner pot 2 detected by the bottom temperature sensor 7, the side temperature of the inner pot 2 detected by the side temperature sensor 8, and non-contact. Each temperature of the top surface temperature of the convex housing part 2a detected by the mold temperature sensor 12 and the internal temperature of the inner pot 2 detected by the lid temperature sensor 9 (internal temperature sensor) is read, and the bottom initial temperature Tb0 at the start of rice cooking t0 These are stored as side surface initial temperature Ts0, top surface initial temperature Tp0, and internal initial temperature Ti0 (S62). Next, the control device 10 controls each inverter circuit (not shown) so that a high-frequency current flows through the convex heating coil 4 and the bottom heating coil 5 (S63), and the inner pot 2 is induction-heated.

  The control device 10 detects the bottom of the inner pot 2 detected by the bottom temperature sensor 7 when a predetermined time t (for example, several seconds) has elapsed since the energization start of the convex heating coil 4 and the bottom heating coil 5 (S64). The temperature Tb, the side surface temperature Ts of the inner pot 2 detected by the side surface temperature sensor 8, and the upper surface temperature Tp of the convex housing part 2a detected by the non-contact type temperature sensor 12 are read (S65).

  And the control apparatus 10 calculates each temperature change value by subtracting each initial temperature Tb0, Ts0, Tp0 at the time of rice cooking start t0 from each temperature Tb, Ts, Tp at the time of fixed time t progress (S66). That is, the control device 10 subtracts the bottom initial temperature Tb0 from the bottom temperature Tb to obtain the bottom temperature change value ΔTb, subtracts the side face initial temperature Ts0 from the side surface temperature Ts to obtain the side surface temperature change value ΔTs, and obtains the top surface temperature Tp. From this, the upper surface initial temperature Tp0 is subtracted to determine the upper surface temperature change value ΔTp.

Thereafter, the control device 10 extracts the set bottom temperature ΔTbj, the set side surface temperature ΔTsj, and the set top surface temperature ΔTpj for determining the amount of rice cooking set corresponding to the internal initial temperature Ti0 at the start of rice cooking t0 (S67). This is the ambient environment at the start of rice cooking, for example, the temperature, the temperature after cooking once, and the internal initial temperature Ti0 differs depending on the temperature in the main body 1 immediately after the heat retention, A set bottom temperature ΔTbj, a set side surface temperature ΔTsj, and a set top surface temperature ΔTpj for rice cooking amount determination according to the internal initial temperature Ti0 are extracted.
Then, the control device 10 determines whether or not ΔTb <ΔTbj and ΔTs <ΔTsj (S68). When ΔTb> ΔTbj and ΔTs ≧ ΔTsj, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “small” and proceeds to S80, but when ΔTb <ΔTbj and ΔTs <ΔTsj, ΔTp It is determined whether or not <ΔTpj (S69).

  When ΔTp <ΔTpj in S69, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “large”, and continues energizing the convex heating coil 4 and the bottom heating coil 5 (S70). Then, the preheating process, the cooking process, the boiling maintenance process, and the uneven process are sequentially performed (S71 to S74), and the rice cooking is ended when the uneven process is completed (S85).

  In the preheating process, the control device 10 controls energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheating temperature. When the preheating temperature is reached, the energization to the convex heating coil 4 and the bottom heating coil 5 is controlled so that the state is maintained. In the cooking process, the control device 10 controls the energization of the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice rises to 98 ° C. (temperature at which the rice is made into α).

  Furthermore, in the boiling maintenance process, the control device 10 controls the energization to the convex heating coil 4 and the bottom heating coil 5 so that the temperature of the cooked rice reaches the boiling temperature, and the rice is turned into α in this state. Keep boiling until. In the unevenness process, the control device 10 stops energization of the convex heating coil 4 and the bottom heating coil 5 and unevenly cooks the cooked rice (rice cooked rice) until the uneven time corresponding to the amount of rice cooked. In each step, the convex heating coil 4 and the bottom heating coil 5 are alternately energized so that natural convection occurs from the central portion of the inner pot, and from the inner peripheral side surface of the inner pot 2. Natural convection may be caused, temperature unevenness in the inner pot 2 is reduced, and cooked rice may be cooked evenly.

  In S69, when ΔTp ≧ ΔTpj, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “medium”, stops energization of the convex heating coil 4, and energizes only the bottom heating coil 5. Continue (S75) and, as described above, perform the preheating step, the cooking step, the boiling maintenance step, and the unevenness step in sequence (S76 to S79), and finish cooking when the unevenness step is completed. (S85).

  In the preheating process, the control device 10 controls energization to the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 rises to the preheat temperature, and the convex housing portion 2a exposed from the cooked rice. The energization to the convex heating coil 4 is performed for a short time so that the temperature does not become abnormal. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible.

  In the cooking process and the boiling maintenance process, the control device 10 is configured so that the energization time to the convex heating coil 4 is gradually longer than that in the preheating process when the rice sucks water to some extent and the volume increases. To. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot 2, and the inner pot The natural convection is caused from the inner peripheral side surface of 2 so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

  Further, in S68, when ΔTb <ΔTbj and ΔTs ≧ ΔTsj, the control device 10 determines that the amount of rice cooked in the inner pot 2 is “small amount”, and stops energization of the convex heating coil 4, Only the bottom heating coil 5 is energized (S80), and as described above, the preheating step, the cooking step, the boiling maintenance step, and the unevenness step are sequentially performed (S81 to S84), and the unevenness step is performed. When finished, the cooking is finished (S85).

  In the preheating process, the control device 10 energizes only the bottom heating coil 5 so that the temperature of the cooked rice in the inner pot 2 becomes the preheating temperature. In the cooking process / boiling maintenance process, the control device 10 absorbs water to some extent and increases the volume so that the convex housing part 2a exposed from the cooked rice does not reach an abnormal temperature. The energization to the convex heating coil 4 is performed for a short time. This is to suppress the water absorption unevenness of the rice in the cooked rice by providing a heat source in the vertical direction as much as possible. In this case, the control device 10 energizes both the convex heating coil 4 and the bottom heating coil 5 substantially simultaneously or alternately so that natural convection occurs from the central portion of the inner pot 2, and the inner pot The natural convection is caused from the inner peripheral side surface of 2 so that the temperature unevenness in the inner pot 2 is reduced and the cooked rice is cooked evenly.

As described above, according to the third embodiment, the bottom initial temperature Tb0, the side surface initial temperature Ts0, the top surface initial temperature Tp0, and the internal initial temperature Ti0 are read at the time of rice cooking start t0 (before induction heating of the inner pot 2). After a certain time t has elapsed since the induction heating of the inner pot 2, the bottom temperature Tb, the side surface temperature Ts and the top surface temperature Tp are read, and the bottom initial temperature Tb0, the side surface initial temperature Ts0 and the The temperature change values ΔTb, ΔTs, and ΔTp are calculated from the upper surface initial temperature Tp0. Then, the set bottom temperature ΔTbj, the set side surface temperature ΔTsj and the set top surface temperature ΔTpj set corresponding to the internal initial temperature Ti0 (internal temperature Ti0) read before induction heating the inner pot 2 are extracted from the table, Each temperature change value ΔTb, ΔTs, ΔTp is compared with each other, and the amount of cooked rice in the inner pot 2 is determined from the comparison result.
Thereby, when the cooked rice is lower than the height of the convex housing part 2a provided at the bottom center of the inner pot 2, that is, even if the amount of cooked rice is small or medium, the amount of cooked rice in the inner pot 2 can be accurately determined. Can be judged. For this reason, there is no shortage of power supply or excessive power supply, and optimal power can be supplied. Moreover, a heating loss and an unnecessary temperature rise of the convex housing portion 2a of the inner hook 2 can be suppressed, and therefore a decrease in durability of the main body 1 such as the inner hook 2 can be suppressed.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Inner hook, 2a Convex accommodating part, 3 Cover body, 4 Convex part heating coil, 5 Bottom part heating coil, 6 Middle container, 6a Convex part, 7 Bottom part temperature sensor, 8 Side surface temperature sensor, 9 Lid temperature sensor, 10 controller, 11 weight sensor, 12 non-contact temperature sensor.

Claims (10)

An intermediate container provided with an opening at the top of the main body, and having a convex portion extending from the bottom to the opening side in a hollow state at the center of the bottom,
An inner hook having a convex accommodating portion that is removably accommodated in the middle container and into which a convex portion of the middle container is inserted at the bottom center;
A lid provided on the main body for opening and closing the opening of the middle container;
A convex heating coil provided on the inner periphery of the convex portion of the middle container;
A bottom heating coil provided at the bottom of the middle container;
A bottom temperature sensor for detecting the bottom temperature of the inner pot;
A side surface temperature sensor for detecting a side surface temperature of the inner pot;
An internal temperature sensor for detecting the internal temperature of the inner pot;
Control means for controlling energization to the bottom heating coil and the convex heating coil, and induction heating the inner pot,
The control means includes a table in which a set bottom temperature, a set side surface temperature, and a set internal temperature for rice cooking amount determination are set in advance in accordance with an internal temperature before the inner pot is induction-heated. Read the bottom temperature, the side surface temperature and the internal temperature before induction heating, read the bottom temperature, the side surface temperature and the internal temperature again after a certain period of time after induction heating the inner pot, Each temperature change value was calculated with the bottom temperature, the side surface temperature, and the internal temperature before induction heating the inner pot , and then set to the internal temperature read before the inner pot was induction heated. setting bottom temperature, extracts the set side temperature and the set internal temperature from the table, the respectively compared with each temperature change value, it determines rice amount within the kiln from the comparison result Rice cooker, wherein the door. An intermediate container provided with an opening at the top of the main body, and having a convex portion extending from the bottom to the opening side in a hollow state at the center of the bottom,
An inner hook having a convex accommodating portion that is removably accommodated in the middle container and into which a convex portion of the middle container is inserted at the bottom center;
A lid provided on the main body for opening and closing the opening of the middle container;
A convex heating coil provided on the inner periphery of the convex portion of the middle container;
A bottom heating coil provided at the bottom of the middle container;
A bottom temperature sensor for detecting the bottom temperature of the inner pot;
A side surface temperature sensor for detecting a side surface temperature of the inner pot;
A non-contact temperature sensor for detecting the upper surface temperature of the convex housing portion of the inner hook;
Control means for controlling energization to the bottom heating coil and the convex heating coil, and induction heating the inner pot,
The control means reads the bottom temperature, the side surface temperature, and the top surface temperature before induction heating the inner pot, and after a predetermined time has elapsed since the induction heating of the inner pot, the bottom temperature, the side surface temperature, and Read the upper surface temperature, calculate the temperature change values of the bottom temperature, the side surface temperature and the upper surface temperature before induction heating the inner pot, and the amount of rice cooked in the inner pot from each temperature change value The rice cooker characterized by determining. An internal temperature sensor for detecting the internal temperature of the inner pot;
The control means includes a table in which a set bottom temperature, a set side surface temperature, and a set top surface temperature for rice cooking amount determination are set in advance in accordance with an internal temperature before the inner pot is induction-heated. The set bottom temperature, the set side surface temperature and the set top surface temperature corresponding to the internal temperature read before induction heating are extracted from the table and compared with the temperature change values, respectively. The rice cooker according to claim 2, wherein the amount of cooked rice is determined. The control means includes a preheating step, a cooking step, a boiling maintenance step, and a unevenness step, and when the amount of cooked rice is within a large range in the inner pot, the bottom heating is performed in each step. The rice cooker according to any one of claims 1 to 3 , wherein both the coil and the convex heating coil are energized. The control means includes a preheating step, a cooking step, a boiling maintenance step, and a unevenness step, and when the amount of cooked rice is within a range of medium amount in the inner pot, preheating among the respective steps. In the process, the energization time of the convex heating coil is made shorter than that of the bottom heating coil, and in the cooking process and the boiling maintenance process, the energization time of the convex heating coil is gradually increased from the energization time in the preheating process. The rice cooker as described in any one of Claims 1-4 characterized by the above-mentioned. The control means includes a preheating step, a cooking step, a boiling maintenance step, and a unevenness step, and when the amount of cooked rice is within a range of a small amount in the inner pot, a preheating step among the respective steps. Then, only the bottom heating coil is energized, and the convex heating coil is energized in the cooking step and the boiling maintaining step, and the energizing time is shorter than the energizing time to the bottom heating coil. cooker according to any one of claim 1-5. The rice cooker according to claim 4 or 5 , wherein the control means alternately energizes the bottom heating coil and the convex heating coil in each step of a preheating step, a cooking step, and a boiling maintenance step . . The rice cooker according to claim 6, wherein the control means alternately energizes the bottom heating coil and the convex heating coil in each step of the cooking step and the boiling maintaining step . The rice cooker according to any one of claims 1 to 8 , wherein a height of the convex housing portion of the inner pot is greater than or equal to a scale indicating a maximum amount of rice cooking in the inner pot. The bottom heating coils, rice cooker according to any one of claim 1 to 9, characterized in that the wound to the height of the scale indicating the minimum cooking amount in the kiln.

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