JP5488253B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker that cooks rice with good taste with little unevenness of cooking and uneven taste.

  A general rice cooking process mainly consists of a pre-cooking process, a cooking process, a boiling maintenance process, and a follow-up cooking process. In the pre-cooking process, the rice temperature is maintained at around 60 ° C. to promote water absorption, The rice temperature is controlled within the range of 63 ° C to 70 ° C to activate the rice enzyme and to control the cooking of the rice to obtain sweetened rice. Bring to a boil.

  However, when heating with high heat from around 60 ° C. to 70 ° C., the gelatinization of rice is rapidly promoted, and the rice grains coalesce to form a large lump. Then, even if it boils, the rice grains adhere to each other and remain in a large lump. It was. In the heating process, the rice and water are agitated by continuing to boil water to promote water absorption and gelatinization of the rice, but if the rice grains remain adhered during boiling, the water will be absorbed by reducing the chance that the rice will come into contact with water. And gelatinization is inhibited.

  Therefore, conventionally, this type of rice cooker moves rice grains by slowing the rate of temperature rise in the rice cooking process, adding vibration or rotating action to the pan, and repeating pressurization and agitation of rice and water in the pan. A technique for reducing cooking unevenness has been proposed (see, for example, Patent Documents 1, 2, and 3).

  FIG. 11: shows the cross-sectional view of the conventional rice cooker described in patent documents 1-3. As shown in FIG. 11, the main body 1, the pot 2, the pot heating means 4, and the rotating means 17 (are configured.

  When rice and water are put into the pot 2 built in the main body 1 and rice cooking is started, the induction coil as the pot heating means 4 is energized and the pot 2 is induction-heated, and at the same time, the rotation motor of the rotating means 17 is rotated. When driven, the pan 2 slowly begins to rotate intermittently, and the water and rice inside the pan 2 start to flow along with the intermittent rotation of the pan 2. The heat of the heated pot 2 spreads to each part of the pot 2 by the flow of water and rice in the pot 2, and the temperature of the water and the rice rises uniformly. The purpose of this is to realize a rice cooker that can cook delicious rice without unevenness in cooking depending on the amount of cooked rice.

JP-A-5-115355 JP-A-7-23851 JP-A-6-225832

  However, the conventional configuration has various problems. If the heating rate is slowed, there is a problem that the cooking time becomes longer or the taste is lowered, and it is difficult to stir the rice and water by repeating the pressurization and dehydration, which is difficult in the pre-cooking process. In addition, it is possible to avoid adhesion between rice grains by adding vibration and rotation to the pan, but if the optimal vibration and rotation are not applied to loosen the rice and water, the rice and water will have uneven water distribution and will be cooked. Causes unevenness.

  In particular, in the case of rotating operation, the rice is biased in the centrifugal direction, so when the rotating operation is performed so that the rice continues to receive force mainly in the centrifugal direction from the start of rice cooking to the end of rice cooking, By forming a concave shape and leaving moisture in the concave portion, the rice near the upper center of the cooked rice has a watery taste.

  Therefore, when the rice near the top of the center is mixed with other parts, the texture and taste of the cooked rice will vary, resulting in uneven rice, and if the user loosens the cooked rice, A bad part is spread throughout, resulting in a taste evaluation result of rice that is not totally delicious.

  The above phenomenon becomes particularly remarkable in short-time rice cooking in which the time of each process is shortened. In other words, by solving the above problems, it is possible to cook delicious rice with no unevenness even when cooking for a short time.

  The present invention solves the above-mentioned conventional problems, by efficiently stirring the rice and water in the pan, the rice grains adhere to each other due to the gelatinization of the rice and become a large lump, which inhibits water absorption or boiling It is an object to provide a rice cooker that eliminates the problem that rice and water are less likely to be agitated by heating, eliminates unevenness in heating, and cooks rice with greatly improved taste.

  In order to solve the conventional problems, the rice cooker of the present invention has a pot, a pot heating means for heating the pot containing rice and water, and a rotating means for rotating the pot, and the rotation The means includes a first rotation for rotating the pan at a first rotation speed for a first predetermined time during rice cooking, and a second rotation for rotating the pan at a second rotation speed for a second predetermined time. By stirring at least once, the rice and water are heated and stirred in the centrifugal and rotational directions, the first predetermined time is longer than the second predetermined time, and the first rotational speed is the second The first rotation is greater than the number of rotations, and is rotated in the direction opposite to the second rotation.

  As a result, when focusing on a single grain of rice, the movement of the rice in the centrifugal direction and the movement in the rotational direction are combined to follow a three-dimensional trajectory, and stirring is promoted more efficiently. Can be agitated, the rice does not adhere to a large lump, the water absorption is promoted evenly for each grain of rice, and the rice grains are not adhered to each other, so stirring the rice and water by boiling Water absorption and gelatinization can be promoted.

  Therefore, the whole rice in the pan has no core or wateriness and can be cooked without unevenness, and can be provided with sweetness without uneven taste. Moreover, by shortening the time of each process in short-time rice cooking, due to the increase in the amount of heating, the temperature in the pan becomes even more uneven until it reaches the set temperature of each process, and the set temperature of each process is reached. It is possible to cook delicious rice that does not have uneven cooking and uneven flavor even when the unevenness of temperature difference is not sufficiently relaxed due to the short holding time.

  The rice cooker of the present invention can be cooked with no core or wateriness in the entire pan and without cooking unevenness, and can provide sweet rice without uneven taste. In addition, it is possible to cook delicious rice without uneven cooking and taste even in short-time cooking. Therefore, the user can surely eat delicious rice without depending on the cooking conditions.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. Sectional drawing of the pan in Embodiment 1 of this invention (A) in the rice cooking process sequence is the pan detection temperature transition diagram (b) is the rice temperature transition diagram Schematic illustration showing how water passes around a group of rice grains Schematic illustration showing how water passes between rice grains BRIEF DESCRIPTION OF THE DRAWINGS (a) which shows the state of the rice and water in the pan of the rice cooker in Embodiment 1 of this invention is a model explanation top view (b) is a model explanation sectional view (A) which shows the state of the rice and water in the pan of the rice cooker of another mode in Embodiment 1 of the present invention is a schematic explanation top view (b) is a schematic explanation sectional view The graph which compared the temperature rise of the rice in the pan of the cooking process of the rice cooker in Embodiment 1 of this invention and the temperature rise of the rice in the pan of the rice cooking process by the conventional quick cooking course (A) is a schematic explanatory top view (b) is a schematic explanatory sectional view showing the state of rice and water in a pan after the completion of rice cooking in the rice cooker in Embodiment 1 of the present invention. The graph which compared the gelatinization degree in the boiling maintenance process in Embodiment 1 of this invention, and the time-dependent change of the gelatinization degree in the rice cooking process by the conventional quick-cooking course. Cross-sectional view of a conventional rice cooker

  1st invention has a pan, the pan heating means which heats the said pan which put rice and water, and the rotation means to rotate the said pan, The said rotation means makes the said 1st predetermined pot at the time of rice cooking. Heat rice and water by performing at least once a first rotation that rotates at a first number of revolutions in time and a second rotation that rotates the pan at a second number of rotations at a second predetermined time. The first predetermined time is longer than the second predetermined time, the first rotational speed is greater than the second rotational speed, and the first rotational speed is By focusing on a single grain of rice by rotating it in the opposite direction to the second rotation, the movement of the rice in the centrifugal direction and the movement in the rotational direction are combined to follow a three-dimensional trajectory. As a result, stirring is further promoted and the rice can be stirred efficiently, and the rice will adhere. Without a great mass is promoted uniformly absorbed by the rice every grain, it is possible to promote the rice water and gelatinized by agitation of rice and water by boiling for rice grains are not coalesce. Therefore, the whole rice in the pan has no core or wateriness and can be cooked without unevenness, and can be provided with sweetness without uneven taste. Moreover, by shortening the time of each process in short-time rice cooking, due to the increase in the amount of heating, the temperature in the pan becomes even more uneven until it reaches the set temperature of each process, and the set temperature of each process is reached. Even when the unevenness of temperature difference is not sufficiently relaxed due to short holding time, delicious rice without uneven cooking and uneven taste can be cooked.

  According to the second invention, in particular, the first predetermined time and the second predetermined time of the first invention are made variable, so that the state of the rice changes as the rice cooking process proceeds. Stirring optimally in the direction and rotation direction can efficiently loosen rice and rice, and three-dimensionally stirring rice can eliminate adhesion between rice and rice in the pre-cooking process, further promoting water absorption However, since the rice grains are not adhered to each other in the heating step, the water absorption and gelatinization of the rice can be further promoted by stirring the rice and water by boiling.

  According to the third aspect of the invention, in particular, by changing the first rotation speed and the second rotation speed of the first or second invention, the rice state changes as the rice cooking process proceeds. In addition, the rice and rice can be efficiently loosened by the optimum stirring in the centrifugal direction and the rotation direction, and the adhesion between the rice and rice can be eliminated in the pre-cooking process by stirring the rice in three dimensions. Water absorption is promoted, and the rice grains are not adhered to each other in the heating step, so that the water absorption and gelatinization of the rice can be further promoted by stirring the rice and water by boiling.

In the fourth aspect of the invention, in particular, when the first rotation of any one of the first to third aspects of the invention is switched to the second rotation, the pan is stopped for a certain period of time. As the rice is stirred, the adhesion between the rice and the rice can be eliminated in the pre-cooking process, the water absorption is further promoted, and the rice grains do not adhere to each other in the heating process. It is possible to further promote water absorption and gelatinization.

  In the fifth aspect of the invention, the rotational state is changed according to the amount of rice cooked in any one of the first to fourth aspects of the invention. Optimum agitation can be used to efficiently loosen rice and rice against changes depending on the amount of rice cooked, and rice can be more efficiently agitated so that the adhesion between rice and rice can be eliminated in the pre-cooking process. Since the rice grains are not adhered to each other in the heating step, the water absorption and gelatinization of the rice can be further promoted by stirring the rice and water by boiling.

  In the sixth aspect of the invention, in particular, the rotation of the pan according to any one of the first to fifth aspects causes sloshing due to resonance to stir the rice and water. Since the water can be agitated and a strong water flow can be caused even with a small rotation amplitude, the reliability can be further improved with respect to quality problems such as vibration, noise and durability caused by the rotation operation.

  In a seventh aspect of the invention, in particular, the pan of any one of the first to sixth aspects of the invention has a gently curved shape connecting the bottom surface and the side surface, and the inner peripheral surface has a diameter toward the opening of the pan. By making the shape expand, the rice in the pan can be stirred more uniformly when rotated, and the centrifugal force causes the rice to move from the center of the pan toward the side of the pan. The rice is lifted while moving along a gently curved surface, and thus efficiently stirred.

  In the eighth aspect of the invention, in particular, the rice cooking process of any one of the first to seventh aspects includes a pre-cooking process, a cooking process for heating water and rice to the boiling temperature from the end of the pre-cooking process, and boiling. It consists of a boiling maintenance process that heats to a temperature higher than the boiling temperature, and a re-cooking process that further accelerates gelatinization of the rice and evaporates excess water. In the pre-cooking process and the cooking process, the rice and water are in the centrifugal direction. Stirring, in the boiling maintaining step and the additional cooking step, the rotation speed of the pan is made slower than the rotation speed of the pan in the pre-cooking step and the cooking step, so that water and rice in each rice cooking step Stirring effect can be effectively acted on, and by setting the number of rotations of the pan and the degree of operation and non-operation for each rice cooking process, rice cooking is performed as desired by the user, shortening the rice cooking time, user It is possible to realize the taste of taste.

  Hereinafter, embodiments of 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. 1 is a cross-sectional view of a rice cooker according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a pot according to the first embodiment of the present invention.

  In FIG.1 and FIG.2, the main body 1 of a rice cooker is equipped with the detachable pan 2 inside. The pan 2 has a gently curved surface shape R connecting the inner bottom surface and the inner peripheral surface, and the inner peripheral surface has a shape whose diameter increases toward the pan opening. As shown in FIG. 2, the inner diameter A in the vicinity of the pan opening is larger than the inner diameter B in the vicinity of the pan bottom.

The main body 1 is provided with a lid 3 covering its upper surface so as to be freely opened and closed. The rice cooker of this Embodiment induction-heats the pan 2 with the method mentioned later, and cooks the rice and water in the pan 2 by heating. The main body 1 has a pot heating means 4 (which is an induction heating coil) for induction heating the bottom of the pot 2, a pot temperature detection means 5 for detecting the temperature of the pot 2, and a control means 6. The lid 3 further includes a heating plate 7 that covers the opening of the pan 2,
A heating plate heating means 8 (which is an induction heating coil) for induction heating the heating plate 7 and a heating plate temperature detection means 9 for detecting the temperature of the heating plate 7 are provided.

  The heating plate 7 is a detachable heating plate with a heating plate seal packing 10 attached to the lower surface of the lid 3. The heating plate 7 has a vapor hole 11 in the center. The heating plate temperature detecting means 9 is pressed against the heating plate 7. The heating plate seal packing 10 was made of a fluororesin having a low frictional resistance.

  Further, the main body 1 has a protective frame 12 for housing the pan 2, and a motor 13 for rotating the pan 2 is attached to the protective frame 12. The pan 2 rotates when the rotational power of the motor 13 is transmitted through the rubber roller 14. A receiving roller 15 is attached to the protective frame 12 at a portion facing the rubber roller 14 with respect to the central axis of the pan 2, thereby preventing the wobbling in the axial direction due to the rotation of the pan 2.

  In addition, in order to make the operation of the pan 2 smooth, a support roller 16 is attached to the protective frame 12 and abuts against the bottom of the pan 2 to prevent generation of vibration and noise associated with the rotation of the pan 2. The rotation speed of the pan 2 can be obtained by changing the rotation speed of the rubber roller 14 by changing the input to the motor 13. The rotating means 17 in the present embodiment includes a motor 13, a rubber roller 14, a receiving roller 15, and a support roller 16.

  The control means 6 has a microcomputer mounted on a circuit board (not shown). The control means 6 (microcomputer) is pre-programmed by software based on operation commands input by a user via an operation panel (not shown), signals input from the pan temperature detection means 5 and the heating plate temperature detection means 9. The heating control of the pan 2 and the heating plate 7 and the operation control of the motor 13 are performed by the rice cooking program stored in the above.

  The control means 6 controls the heating amount of the pan heating means 4 and the heating plate heating means 8 and the operation of the motor 13 by the energization rate and / or the energization amount of each heating means and motor. In this embodiment, the pot 2 and the heating plate 7 are heated to cook rice and water that are to be cooked, and the pot heating means 4 and the heating plate heating means 8 are placed in the pot. It is used as a heating device that heats food.

About the rice cooker comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.
A user puts rice to be cooked and water corresponding to the amount of the rice into the pan 2 and decorates the main body 1. Further, when the user selects a desired rice cooking menu and operates a rice cooking start switch (not shown), the rice cooking process is performed.

  The rice cooking process is largely divided into pre-cooking, cooking, maintaining boiling, and additional cooking in chronological order.

  FIG. 3A shows a pan detection temperature transition diagram, and FIG. 3B shows a rice temperature transition diagram in the rice cooking process sequence.

  As shown in FIG. 3, there is a correlation between the pot detection temperature and the cooked rice temperature, and the cooked rice temperature can be detected by detecting the pot temperature. Therefore, in this Embodiment, the pan temperature detection means 5 acts as a temperature detection part which detects the temperature of the to-be-cooked item in a pan.

In the pre-cooking process A, the temperature of the rice is maintained at around 60 ° C., which is lower than the gelatinization temperature, to promote water absorption, and in the subsequent processes, the rice is sufficiently gelatinized to the center of the rice, or the temperature of the rice The rice cooking is controlled such that the enzyme of white rice is activated by bringing the temperature within the range of 63 ° C. to 70 ° C. to obtain sweetened rice. In this embodiment, a first predetermined temperature T1 (60 ° C.) suitable for water absorption of rice.
Based on the temperature value signal detected by the pan temperature detecting means 5 and the heating plate temperature detecting means 9, the control means 6 controls the pot heating means 4 to heat the rice and water in the pot.

  Next, in the cooking step B, the pan 2 is heated with a predetermined amount of heat by the pan heating means 4 until the temperature of the pan 2 reaches a second predetermined temperature T2 (boiling point of water, usually around 100 ° C.). Boil the water inside. The amount of cooked rice is also determined based on the temperature rise rate at this time (signal input from the heating plate temperature detecting means 9).

  In the boiling maintenance step C, as shown in FIG. 3 (a), while the pot 2 has water, the detected temperature Ta of the pot temperature detecting means 5 is the second predetermined temperature T2 (boiling point of water. Usually around 100 ° C.). ), The control means 6 controls the pot heating means 4 and the heating plate heating means 8 so that the pot heating means 4 heats the pot 2 and heats rice and water. And if the boiling maintenance process C passes, the water in the pan 2 will evaporate, and if there is no water in the pan 2, the temperature of the pan 2 will rise. When the detected temperature Ta of the pot temperature detecting means 5 reaches the third predetermined temperature T3 (above the boiling point of water), it is determined that there is no water in the pot 2 and the process ends. This step is a step of gelatinizing rice starch, and the degree of gelatinization of rice after cooking reaches nearly 100%, but the degree of gelatinization is about 50 to 60% at the end of this step.

  Finally, in the additional cooking step D, as shown in FIG. 3A, the detected temperature Ta of the pan temperature detecting means 5 is the second predetermined temperature T2 until the second predetermined time t2 (usually around 15 minutes). The control means 6 controls the pot heating means 4 and the heating plate heating means 8 according to the amount of cooked rice so that it is maintained at (normally around 100 ° C.). Repeat (pause). The additional cooking process is a process of further promoting gelatinization of rice starch and evaporating excess water following the boiling maintaining process, and the gelatinization degree was about 50 to 60% at the start of the additional cooking process. At the end of the cooking process, that is, at the end of cooking, the degree of gelatinization reaches nearly 100%.

  When such a rice cooking process is executed, the detected temperature Ta of the pot temperature detecting means 5 is changed in temperature as shown in FIG. 3A, and the temperature Tb in the pot 2, that is, the temperature of rice is shown in FIG. 3B. To do.

  Normally, when heating with high heat from around 60 ° C. to 70 ° C. in the pre-cooking process, the gelatinization of rice is rapidly promoted and the rice grains coalesce into a rice grain group, and the rice grains adhere to each other at the time of boiling. Since the rice was heated as it was, the rice near the side of the pan became hard rice due to overheating, and the rice near the center of the pan became watery rice, which caused cooking unevenness. Also, in the heating process, the rice and water are stirred by continuing to boil the water, and the rice absorbs water and promotes gelatinization. However, if the rice grains remain adhered during boiling, the rice inside the rice grains will contact the water. Water absorption and gelatinization are hindered by reducing the opportunity to do.

FIG. 4 is a schematic explanatory diagram showing a state in which water passes around the rice grain group.
As shown in FIG. 4, when a plurality of rice grains R1 adhere to each other to form a rice grain group RG1, the water W1 moves outside the rice grain group RG1, as indicated by the dotted arrow in FIG. For this reason, the contact area of the water W1 per one rice grain R1 becomes small, and the water absorption of the rice R1 becomes worse.

  In the present embodiment, the motor 13 is controlled so that the user reaches the target rice cooked state for each step of pre-cooking, cooking, boiling maintenance, and additional cooking, and the pan 2 is rotated at a predetermined time for a predetermined time. A predetermined number of rotations are performed to give the rice and water in the pan 2 an optimal movement.

FIG. 5 is a schematic explanatory view showing how water passes between rice grains. As shown in FIG. 5, the optimal movement is given to the rice and water in the pan 2, so that the rice is dispersed and the formation of rice grain aggregates is inhibited, and the rice grains R1 and R1 adhere to each other. It will be in a state of falling apart. Therefore, the water W1 in the pan 2 moves between the rice grains R1, R1 adjacent to each other, as shown by the dotted arrows in FIG.
The contact area of the water W1 per one rice grain R1 increases.

  FIG. 6: shows the state of the rice and water in the pan of the rice cooker of the 1st Embodiment of this invention, (a) is a schematic explanatory top view, (b) shows a schematic explanatory sectional view.

  In the pre-cooking step, the pan 2 repeats normal rotation and reversal at a predetermined time for a predetermined number of rotations, and the normal rotation time is longer than the reversal time, and the normal rotation speed is larger than the reversal speed (this embodiment In this case, the rice is rotated in the clockwise direction at 60 rpm for 1 second and then reversed in the counterclockwise direction at 14 rpm for 0.8 second), and the rice is stirred three-dimensionally as shown in FIG. Rice adhesion can be eliminated, water absorption is further promoted, rice is not adhered to each other in the cooking and boiling maintenance process, and rice water absorption and gelatinization are further promoted by stirring rice and water by boiling Can do.

  That is, by rotating clockwise at 60 rpm, the centrifugal force decreases when the rice heading from the center of the pan to the side of the pan by centrifugal force turns counterclockwise after 1 second, and the center of the pan from the side of the pan Returned to

  When the direction of rotation switches from normal rotation to reverse, the acceleration in the rotation direction changes, and the rice near the pan surface tries to move in the reverse direction due to frictional force, but the other rice has inertial force. In order to keep rotating in the forward rotation direction, the rice is stirred in the rotation direction.

  At this time, since the pan surface is usually smooth, the frictional force between the pan surface and the rice is small, and the inertia force of the whole rice is larger. It is necessary to lengthen the predetermined time and the second predetermined time, and it cannot be stirred efficiently. When the first predetermined time and the second predetermined time are short, it is difficult to stir as if the rice and the pan surface slip and the rice looks like.

  Therefore, in order to efficiently stir, it is necessary to make the time obtained by adding the first predetermined time and the second predetermined time as short as possible. The first predetermined time is longer than the second predetermined time. In addition, it is necessary to consider the optimum conditions for the first rotation speed and the second rotation speed.

  Next, when both the first rotation speed and the second rotation speed are high-speed rotation, it is difficult to stir as if the rice and the pan surface slip and the rice looks like the first rotation speed. When both the second rotation speeds are low-speed rotation, the friction force between the rice and the pan surface is larger than the inertia force of the whole rice, and it is difficult to stir the rice as if it were.

  Therefore, by making the first rotation speed larger than the second rotation speed, the inertial force is gradually reduced when the first rotation (forward rotation) is changed to the second rotation (reverse rotation), and the second rotation speed is decreased. It becomes effective to use the frictional force of the rice near the pan surface for stirring.

  Therefore, the first predetermined time is longer than the second predetermined time, and the first rotational speed is greater than the second rotational speed, whereby the rice can be stirred more efficiently. In this embodiment, an operation of rotating clockwise at 60 rpm for 1 second (forward rotation) and then rotating counterclockwise at 14 rpm for 0.8 seconds (reversal) is performed repeatedly to efficiently stir the rice. Is something you can do.

In other words, when focusing on a single grain of rice, the movement of the rice in the centrifugal direction and the movement in the rotational direction are combined to follow a three-dimensional trajectory. Can be mixed, the rice does not stick together to form a big lump, the water absorption is promoted evenly for each grain of rice, and the rice grains do not adhere to each other, so the rice absorbs water by stirring the rice and water by boiling And gelatinization can be promoted.

  By the above operation, the whole rice in the pan has no core or wateriness, and can be cooked without uneven cooking, and can provide sweet rice without uneven taste. Moreover, by shortening the time of each process in short-time rice cooking, due to the increase in the amount of heating, the temperature in the pan becomes even more uneven until it reaches the set temperature of each process, and the set temperature of each process is reached. It is possible to cook delicious rice that does not have uneven cooking and uneven flavor even when the unevenness of temperature difference is not sufficiently relaxed due to the short holding time.

  In addition, by stirring the rice and water in the centrifugal direction and the rotating direction while varying the first predetermined time and the second predetermined time, by the optimal stirring against the state of the rice changing as the rice cooking process proceeds Efficiently loosening rice and rice.

  For example, in the rice cooking process, until the pre-cooking process, where the temperature is adjusted to a temperature suitable for water absorption of rice, the rice is not sufficiently absorbed and the gelatinization of the rice has not progressed. The surface is not sticky. Since the frictional force between the pan surface and the rice is not large in this rice state, when the first rotation is changed to the second rotation by increasing the first predetermined time and the second predetermined time. The rice can be efficiently loosened by promoting the stirring of rice in the axial direction.

  Further, in the latter half of the pre-cooking process, water absorption of the rice has progressed, and gelatinization of the surface of the rice has started. In this rice state, the frictional force between the pan surface and the rice is increasing, so the first rotation is changed to the second rotation by shortening the first predetermined time and the second predetermined time. When turning, it can efficiently stir the rice in the axial direction and efficiently loosen the rice.

  Therefore, the rice is stirred three-dimensionally so that the adhesion between the rice and the rice can be eliminated in the pre-cooking process, the water absorption is further promoted, and the rice grains are not adhered to each other in the heating process. This can further promote water absorption and gelatinization of rice.

  Similarly, by changing the first rotation speed and the second rotation speed while stirring the rice and water in the centrifugal direction and the rotation direction, the state of the rice changes as the rice cooking process proceeds. Stirring can also efficiently loosen rice.

  For example, until the pre-cooking process, where the temperature is adjusted to a temperature suitable for water absorption in the rice cooking process, the rice surface has not absorbed water sufficiently and the gelatinization of the rice has not progressed. There is no stickiness. Since the frictional force between the pan surface and the rice is not large in this rice state, the first rotation turns to the second rotation by reducing the first rotation speed and the second rotation speed. The rice can be efficiently loosened by promoting the stirring of rice in the axial direction.

  Further, in the latter half of the pre-cooking process, water absorption of the rice has progressed, and gelatinization of the surface of the rice has started. In this rice state, since the frictional force between the pan surface and the rice is increasing, the first rotation is changed to the second rotation by increasing the first rotation speed and the second rotation speed. When turning, it can efficiently stir the rice in the axial direction and efficiently loosen the rice.

  Therefore, the rice is stirred three-dimensionally so that the adhesion between the rice and the rice can be eliminated in the pre-cooking process, the water absorption is further promoted, and the rice grains are not adhered to each other in the heating process. This can further promote water absorption and gelatinization of rice.

  By stirring while changing the number of rotations, the water in the pan 2 can be sloshing due to resonance, rice and water can be stirred with less energy, and a strong water flow can be caused even with a small rotation amplitude. For example, when the pot 2 is shaken at a constant period (for example, repetition of 30 rotations and 50 rotations) in the first rotation, the water in the pot 2 undulates. This phenomenon is well known as the sloshing phenomenon.

  Sloshing is a phenomenon in which the liquid level in the tank swells when a vessel containing liquid, such as a tank, is subjected to periodic vibrations. If a significant sloshing occurs, the structure is destroyed. Etc. When the sloshing phenomenon occurs, the liquid level reaches a level that cannot be assumed under normal conditions, and the rice is stirred. Therefore, it is not necessary to increase the rotation speed for stirring rice and water, and effective rice stirring can be performed with less energy.

  Therefore, it is possible to further improve the reliability with respect to quality problems such as vibration, noise, and durability due to the rotating operation.

  By the way, as shown in FIG. 2, since the pan 2 has a gently curved surface shape R connecting the inner bottom surface and the inner peripheral surface, and the inner peripheral surface is a shape whose diameter increases toward the pan opening, When it is rotated, the rice in the pan can be stirred more uniformly, and the rice moves along the gently curved shape in the movement of the rice from the center of the pan to the side of the pan by centrifugal force. As the rice moves up while moving, it is more efficiently promoted that rice is stirred three-dimensionally.

  7A and 7B show a state of rice and water in a pan of a rice cooker according to another aspect of the first embodiment of the present invention, wherein FIG. 7A is a schematic top view, and FIG. 7B is a schematic cross-sectional view. It is.

  As shown in FIG. 7, when the pan 2 is switched between normal rotation and reversal, the pan 2 is stopped for a certain period of time so that the rice is agitated three-dimensionally, thereby eliminating the adhesion between the rice and the rice in the pre-cooking process. Water absorption is further promoted, and the rice grains are not adhered to each other in the heating step, so that the water absorption and gelatinization of the rice can be further promoted by stirring the rice and water by boiling.

  For example, when the first rotation (forward rotation) is started and the rice that has been turned from the center of the pan to the side of the pan by centrifugal force is reduced in rotation, the centrifugal force decreases and the rice is returned from the side of the pan to the center of the pan. When turning to the second rotation (reversal), the rice moves in the rotation direction by changing the acceleration in the rotation direction.

  Therefore, when focusing on one grain of rice, the movement of the rice in the centrifugal direction and the movement in the rotation direction are combined to follow a three-dimensional trajectory, and the movement direction changes periodically and every rotation cycle. The moving distance becomes longer, and the stirring is further promoted.

  In addition, by changing the rotation state according to the amount of rice cooked, the friction force between the pan surface and the rice and the inertial force of the whole rice is efficiently loosened by optimal stirring against the change in the amount of rice cooked. be able to.

  For example, in the case of 1 rice cooking amount, since the friction force between the pan surface and the rice and the inertia force of the whole rice are both small, the first predetermined time and the second predetermined time are set short, and the first By setting the number of rotations and the second number of rotations to be small, rice can be efficiently loosened.

  Moreover, in the case of the amount of cooked rice 5 go, both the friction force between the pan surface and the rice and the inertia force of the whole rice are both large, so the first predetermined time and the second predetermined time are set long, and the first By setting the rotation speed and the second rotation speed large, rice and rice can be efficiently loosened.

Therefore, the rice is more efficiently stirred so that the adhesion between the rice and the rice can be eliminated in the pre-cooking process, and the water absorption is further promoted. Stirring can further promote rice water absorption and gelatinization.

  By stirring rice three-dimensionally, the temperature in the pan can be made more uniform, but this indicates that the rice and rice are in a loose state without sticking to each other due to stirring. is there. Because, if the rice and rice are in a state of adhesion, the heat transfer from the bottom of the pan 2 is mainly due to heat conduction in which the rice grains are regarded as a large lump of rice, and shows a temperature distribution with a very large temperature difference. It is. The above is clear from the distribution comparison of the temperature in the pan shown in FIG.

  FIG. 8 is a graph comparing the temperature rise of the rice in the pan in the cooking process of the rice cooker in Embodiment 1 of the present invention and the temperature rise of the rice in the pan in the rice cooking process by the conventional quick cooking course.

  As shown in FIG. 8, the temperature difference between the rice at the center of the pan and the bottom of the pan in the present embodiment is significantly smaller in a shorter time than that in the conventional quick cooking course, and the temperature becomes uniform faster. You can see that In the conventional quick cooking, the rice at the bottom of the pan close to the pan heating means 4 is rapidly gelatinized and the pasting of only the surface of the rice is progressing at a stretch in a state where water is not sufficiently absorbed to the inside of the rice. As a result, the adhesion between rice and rice is promoted, and the amount of heat given to a single grain of rice can be further different, which leads to a difference in the degree of gelatinization of rice, which leads to uneven cooking and uneven taste.

  By rotating the pan 2 in the pre-cooking process, the rice and the rice are prevented from sticking together, and the water is always brought into contact with the rice, thereby improving the contact efficiency between the rice and the water and improving the water absorption performance. Can do. Therefore, in the pre-cooking process, the rice can be sufficiently absorbed in a short time, so that it becomes cooked rice where gelatinization has not progressed to the center of the rice due to insufficient water absorption as before. There is no.

  By rotating the pan 2 in the cooking process, it is possible to eliminate the uneven cooking in the cooking process, which is one of the processes in which uneven cooking is likely to occur, and to prevent a decrease in taste. In other words, in the cooking process where the input power to the pan is large, the temperature of the rice suddenly rises, and gelatinization progresses only on the surface of the rice at a stretch with the water not sufficiently absorbed into the inside of the rice. By inhibiting water absorption, the rice with the core remaining was cooked, which was one of the causes of uneven cooking.

  Therefore, the rice and water are agitated by the rotation of the pot 2, and the rice is stirred three-dimensionally to avoid the state where the same rice is always in close contact with each other, thereby eliminating the uneven cooking and the contact efficiency between the rice and water. Water absorption can be promoted by improving.

  Moreover, in a boiling maintenance process, water absorption promotion and gelatinization can be accelerated | stimulated by making the pan 2 rotate at low speed | strength of the grade which does not bias rice and water to a centrifugal direction.

  That is, by rotating the pan 2 in the pre-cooking process and the cooking process, the rice grains are not adhered to each other, and the water absorption and gelatinization of the rice by stirring the rice and water by boiling can be promoted. In addition, by rotating the pan, it is possible to reduce uneven heating by causing the boiling to occur uniformly from the bottom of the pan. Furthermore, in the boiling maintenance process, the water in the pan is reduced due to the evaporation of water by boiling and the water absorption of the rice. At this time, since the pan is rotating slowly, the rice is biased in the centrifugal direction and the central part Since there is no uneven distribution of moisture in the pan and the moisture distribution in the pan is uniform, the cooking is very uneven. The cooked rice surface is flat and of good quality. The schematic explanatory drawing which shows the state of the rice and water in the pan after the rice cooking completion of the rice cooker in FIG. 9 is shown.

  Therefore, the whole rice in the pan has no core or wateriness, and can be cooked without unevenness, and can provide sweet rice without uneven taste.

  Furthermore, by shortening the time of each process in short-time rice cooking, due to the increase in the amount of heating, the temperature in the pan becomes even more uneven until it reaches the set temperature of each process, and the set temperature of each process is reached. In this embodiment, it is possible to cook delicious rice that has no unevenness in cooking and uneven taste, even for an increase in uneven cooking due to insufficient relaxation of the temperature difference due to short holding time. .

  FIG. 10 is a graph comparing the degree of gelatinization in the boiling maintaining process in the first embodiment of the present invention and the change over time in the degree of gelatinization in the rice cooking process using the conventional quick cooking course.

  As shown in FIG. 10, in this embodiment, the gelatinization degree is increased to 95% in about 10 minutes. However, the conventional quick cooking does not reach 80% even in 10 minutes. Concerned. This is because in early cooking (short-time rice cooking), in order to heat in a short time, gelatinization of only the surface of the rice progresses at a stretch in a state where water has not been sufficiently absorbed up to the inside of the rice, and further surface gelatinization As a result of the adhesion of rice and rice into a large lump of rice in the pan, water absorption into the rice is inhibited in the early stage of the boiling maintenance process, indicating a phenomenon in which gelatinization is insufficient.

  In the present embodiment, in the pre-cooking process and the cooking process, by stirring rice and water by rotating the pan, the rice is stirred three-dimensionally to avoid the state where the same rice is always in contact, By eliminating the unevenness of cooking and improving the contact efficiency between rice and water, water absorption can be promoted to the inside of the rice in a short time. Regardless of the decrease in moisture in the pan due to the water absorption of rice, there is no uneven distribution of rice and moisture, and the moisture distribution in the pan is uniform, so the cooking surface is very uneven and the cooked rice surface is flat. The quality will be good.

  As described above, the rice cooker according to the present invention can be used as a non-cooking rice with no core or wateriness in the whole rice in the pan, so that it can be used for other cooking devices. Is also applicable.

DESCRIPTION OF SYMBOLS 1 Main body 2 Pan 3 Lid 4 Pan heating means 5 Pan temperature detection means 6 Control means 7 Heating plate 8 Heating plate heating means 9 Heating plate temperature detection means 10 Heating plate seal packing 11 Steam hole 12 Protective frame 13 Motor 14 Rubber roller 15 Receiving roller 16 Support roller 17 Rotating means

Claims (8)

A pan, a pan heating means for heating the pan filled with rice and water, and a rotating means for rotating the pan; the rotating means includes a first pan at a first predetermined time during rice cooking. A first rotation that rotates at a rotation speed and a second rotation that rotates the pan at a second rotation speed at a second predetermined time at least once each time while heating rice and water, The first predetermined time is longer than the second predetermined time, the first rotational speed is greater than the second rotational speed, and the first rotational speed is the second rotational speed. A rice cooker that rotates in the opposite direction. The rice cooker according to claim 1, wherein the first predetermined time and the second predetermined time are variable. The rice cooker according to claim 1 or 2, wherein the first rotation speed and the second rotation speed are variable. The rice cooker according to any one of claims 1 to 3, wherein the pan is stopped for a certain time when the first rotation is switched to the second rotation. The rice cooker of any one of Claims 1-4 which was made to change a rotation state according to the amount of rice cooking. The rice cooker according to any one of claims 1 to 5, wherein sloshing due to resonance is caused by rotation of the pan to stir rice and water. The said pan has the gentle curved surface shape which connects a bottom face and a side surface, and the inner peripheral surface was made into the shape which a diameter expands toward the opening part of the said pan, The description of any one of Claims 1-6 rice cooker. The rice cooking process further includes a pre-cooking process, a cooking process in which water and rice are heated to the boiling temperature from the end of the pre-cooking process, a boiling maintaining process in which the boiling is heated to a temperature higher than the boiling temperature, and gelatinization of the rice. It consists of a cooking process that promotes and evaporates excess water, stirs rice and water in the centrifugal direction in the pre-cooking process and the cooking process, and the rotation speed of the pan in the boiling maintenance process and the cooking process The rice cooker of any one of Claims 1-7 which made it slower than the rotational speed of the said pan in the said pre-cooking process and the said cooking process.