JP2010148801A - Electric rice cooker and rice-cooking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric rice cooker capable of reducing unevenness in cooking rice caused by a difference in amount of rice cooked, thereby cooking delicious rice regardless of the amount of rice cooked. <P>SOLUTION: The electric rice cooker includes: a heater for heating an object to be cooked in a pot; and a controller for performing a rice cooking process by controlling the heater. The controller controls the amount of heating in the heater in response to the amount of rice cooked in the pot, so that a first time (a) to be required for a heating start step I has a prescribed time, and the first time (a) and a second time b to be required for a boiling keeping step II have a certain relationship between them, regardless of the amount of rice cooked in the pot. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric rice cooker and a rice cooking method, and more particularly to a technique for reducing unevenness in cooking due to a difference in the amount of rice cooked.

  A recent electric rice cooker (hereinafter simply referred to as “rice cooker”) is equipped with a microcomputer, and the microcomputer controls the rice cooking process. The rice cooking process controlled by the microcomputer includes a water absorption process for absorbing a predetermined amount of water in the cooked rice in the pan, a rising heating process for heating the absorbed cooked rice until it boils, and this cooked rice The boiling maintenance process which maintains a thing in a boiling state, the steaming process which steams a to-be-cooked rice, the heat retention process which heat-retains at predetermined temperature, etc. are contained.

In such a rice cooker, when the amount of rice cooked in the pot of the rice cooker is different, it is known that delicious rice can be cooked by making the rice cooker control by the microcomputer different depending on the amount of rice cooked ( For example, see Patent Document 1). Specifically, in Patent Document 1, the rice cooking capacity of the cooked rice put in the inner pot is determined in advance, and the cooking process (the above-described startup heating process) according to the determined rice cooking capacity (total number) The same as the above), and the rice cooking process is performed by setting an ideal rice cooking curve (internal hot pot temperature rise curve). And according to this, in the cooking process, because the cooking temperature can be cooked according to this curve by setting a standard temperature rise curve in the standard pan according to the rice cooking capacity, it is possible to cook delicious rice regardless of the rice cooking capacity. Is done.
Japanese Patent Laid-Open No. 5-176837 (for example, paragraphs [0009] to [0010], FIG. 5)

  According to the rice cooking control method disclosed in Patent Document 1, even when the amount of cooked rice in the pan is greatly different, the heating control is performed according to the amount of cooked rice. Delicious rice can be cooked with any amount of rice. However, in recent years, there has been a strong demand for a rice cooker that can cook more delicious rice, and a rice cooker that cooks more delicious rice by reducing unevenness in cooking due to a difference in the amount of cooked rice is desired.

  Therefore, an object of the present invention is to provide an electric rice cooker and a rice cooking method capable of reducing the unevenness of cooking due to the difference in the amount of cooked rice and cooking delicious rice in any amount of cooked rice.

  As a result of intensive investigations regarding rice cooking control to achieve the above objective, not only the time required for the start-up heating process but also the time required for the start-up heating process and boiling maintenance in reducing unevenness due to the difference in the amount of rice cooked It was discovered that the relationship with the time required for the process is important, and the present invention has been completed.

  In order to achieve the above object, an electric rice cooker according to claim 1 is a rice cooker main body having a pan in which a cooked rice containing water and rice is accommodated, and an opening in which the pan is accommodated. An electric rice cooker comprising: a lid that closes the opening; a heating device that heats the rice to be cooked in the pan; and a control device that controls the heating device to perform a rice cooking process. The process includes a water absorption process for absorbing water into the rice, a rising heating process for heating the cooked food absorbed in the water absorption process until boiling, and a boiling maintenance process for maintaining the cooked rice in a boiling state. The control device is configured so that the first time required for the start-up heating step is a predetermined time and the first time when the amount of cooked rice in the pan is any amount. The pan so that the time and the second time required for the boiling maintenance step have a certain relationship And controlling the heating amount of the heating device according to the rice amount.

  Here, the predetermined time includes, for example, a time in which an appropriate amount of water is absorbed by the rice in the pot in the standing heating process, and this time is obtained by an experiment, for example.

  According to a second aspect of the present invention, in the electric rice cooker according to the first aspect, the certain relationship is a relationship in which the first time and the second time are substantially the same.

  According to a third aspect of the present invention, in the electric rice cooker according to the first or second aspect, the control device includes a storage unit that stores a rice cooking amount and a heating control pattern in association with each other, and the control device includes: The heating control pattern corresponding to the amount of cooked rice in the pan is read from the storage unit and the heating device is controlled.

  Invention of Claim 4 is an electric rice cooker in any one of Claim 1 to 3. The pressure valve which controls the pressure valve which adjusts the pressure in the said pan to the said cover body, and the pressure valve which controls the said pressure valve A mechanism is provided, and the control device controls the heating device and the valve opening / closing mechanism to execute the rice cooking step.

  Invention of Claim 5 is an electric rice cooker in any one of Claim 1 to 4. The pressure detection part which detects the pressure in the said pan, The detection value of the said pressure detection part is input, and the said pot inside And a rice cooking amount determination unit for determining the amount of rice cooking, and in the water absorption step, the controller raises the temperature of the pot to a predetermined temperature by the heating device after sealing the pot, and detects the pressure. The pressure value in the pan is detected by a portion, and the detected value is input to the rice cooking amount determination unit to determine the amount of rice cooking in the pan.

  In order to achieve the above object, the rice cooking method according to claim 6 is a rice cooking method in which a rice cooking process including water and rice is accommodated in a pan and a rice cooking process is performed, and the rice cooking process includes: Includes a water absorption step for absorbing water into the rice, a rising heating step for heating the cooked rice absorbed in the water absorption step until boiling, and a boiling maintenance step for maintaining the cooked rice in a boiling state. Even when the amount of cooked rice in the pan is any amount, the first time required for the start-up heating step is a predetermined time, and the first time required for the first time and the boiling maintenance step The rice cooking is performed while controlling the heating amount according to the amount of rice cooking in the pan so that the time of 2 is in a fixed relationship.

  Here, the predetermined time includes, for example, a time in which an appropriate amount of water is absorbed by the rice in the pot in the standing heating process, and this time is obtained by an experiment, for example.

  The invention according to claim 7 is the rice cooking method according to claim 6, wherein the certain relationship is a relationship in which the first time and the second time are substantially the same.

  This invention has the following outstanding effects by providing the said structure. That is, according to the invention of claim 1, in addition to the time required for the start-up heating process, the relationship between the time required for the start-up heating process and the time required for the boiling maintenance process is considered, In this case, rice is cooked at the same time. For this reason, the cooking unevenness by the difference in the amount of rice cooking in a pan can be reduced, and it can be set as the same rice cooking in the case of any rice cooking amount.

  According to the invention of claim 2, the rice cooking process is executed by controlling the heating amount of the heating device so that the time required for the start-up heating process and the time required for the boiling maintenance process are substantially the same. In this case, by setting the predetermined time required for the start-up heating process to a time during which the appropriate amount of water is absorbed by the rice in the pan in the start-up heating process, A moisture content can be made into a preferable value. In other words, according to the present invention, it is possible to cook delicious rice that does not give a rough or sticky impression.

  According to invention of Claim 3, it is the structure which reads the heating control pattern according to the amount of rice cooking from a memory | storage part, and performs a start-up heating process and a boiling maintenance process, and it is easy to perform control operation of a control apparatus.

  According to invention of Claim 4, in the rice cooker of the pressure system which performs not only heating control but also pressure control in a rice cooking process, the unevenness of the cooking by the difference in the amount of rice cooking in a pot is eliminated, and any rice cooking In the case of quantity, the same cooking can be made.

  According to invention of Claim 5, since it is the structure which judges the amount of rice cooking in a pot using pressure instead of temperature, about initial rice water temperature (temperature of the water used for rice cooking) about the amount of rice cooking in a pan. Accurate determination can be made without being affected. Thereby, in the start-up heating process and boiling maintenance process to be performed later, in order to be able to control the heating device based on the exact amount of cooked rice, there is no unevenness of cooking due to the difference in the amount of cooked rice, In some cases it is easy to cook delicious. And since this invention is the structure which pressurizes the inside of a pot in a water absorption process, since the moisture content of the rice in a water absorption process can be raised, it becomes possible to cook more delicious rice.

  According to the invention of claim 6, in addition to the time required for the start-up heating process, the relationship between the time required for the start-up heating process and the time required for the boiling maintenance process is also taken into consideration in any rice cooking amount. Cooked rice at the same time. For this reason, the cooking unevenness by the difference in the amount of rice cooking in a pan can be reduced, and it can be set as the same rice cooking in the case of any rice cooking amount.

  According to the seventh aspect of the invention, the rice cooking process is executed by controlling the amount of heating applied to the cooked rice so that the time required for the start-up heating process and the time required for the boiling maintenance process are substantially the same. In this case, by setting the predetermined time required for the start-up heating process to a time during which the appropriate amount of water is absorbed by the rice in the pan in the start-up heating process, A moisture content can be made into a preferable value. In other words, according to the present invention, it is possible to cook delicious rice that does not give a rough or sticky impression.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a pressure rice cooker (hereinafter simply referred to as “rice cooker”) as a rice cooker for embodying the technical idea of the present invention. It is not intended to be specific to the device, and other embodiments within the scope of the claims are equally applicable.

  First, the structure of the rice cooker which concerns on one Embodiment of this invention is demonstrated, referring FIGS. 1-4. FIG. 1 is a front view of a pressure rice cooker according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the pressure rice cooker of FIG. FIG. 3 is an enlarged view of the pressure valve opening mechanism of FIG. FIG. 4 is an enlarged view of a portion X in FIG.

  In addition, the capacity | capacitance of the rice cooker 1 of this embodiment is 1.0L (5.5 go cooking). However, the application range of the present invention is not limited to the rice cooker having this capacity. For example, the present invention can be applied to a rice cooker having a capacity of 1.8 L (one-cooked).

  As shown in FIGS. 1 and 2, the rice cooker 1 includes a pan 10 into which a cooked rice containing rice and water is put, an opening in which the pan 10 is accommodated, and the pan 10 inside. A rice cooker main body (hereinafter referred to as a main body) 2 having a bottom heater 5 and a side heater (side heater) 6 for heating and heating the cooked rice, and an opening of the main body 2 pivoted on one side of the main body 2 A lid body 11 having a lock mechanism 21 that covers and locks in a closed state, a pressure valve 13 that is attached to the lid body 11 to adjust the pressure in the pan 10, and a pressure valve opening that controls the opening and closing of the pressure valve 13 A mechanism 15, a display operation unit 8 that performs operations such as start of rice cooking, timer reservation, and heat retention, and a bottom heater 5, a side heater 6, and an inner lid heater 19 to be described later according to a rice cooking start signal from the display operation unit 8. Having a heating device and a pressure valve opening mechanism 15 etc. And Gosuru controller 9, and a.

  The control device 9 is provided with a storage unit. The storage unit heats the cooked rice in the pan 10 to a predetermined temperature and absorbs a predetermined amount of water over the predetermined time. Process, rising heating process for heating and heating the absorbed cooked rice until boiling, boiling maintaining process for maintaining the cooked rice in a boiling state, steaming process for steaming the cooked rice after the boiling maintaining process, The rice cooking and the heat retention program which perform sequentially the heat retention process etc. which heat-retained the cooked rice cooked after the steaming process at predetermined temperature are memorize | stored. Among these rice cooking processes, in the rising heating process and the boiling maintenance process, the inside of the pan is pressurized to atmospheric pressure or higher, for example, about 1.1 to 2.2 atmospheres, and the rice cooking process is executed.

  In addition, the rice cooker 1 changes the heating control pattern in a heating apparatus according to the amount of rice cooking as mentioned later. For this reason, the amount of cooked rice is divided into a plurality of layers (for example, divided into three layers of small, medium, and many), and a plurality of programs are prepared so that different heating control patterns are executed for each layer. A plurality of programs are stored in the storage unit provided in the control device 9 in association with the amount of cooked rice. The storage unit also stores data relating the pressure value and the amount of cooked rice.

  The main body 2 is composed of a bottomed box-type outer case 3 and an inner case 4 which is accommodated in the outer case 3 and in which the pot 10 is accommodated, and a gap is formed between the outer case 3 and the inner case 4. And a control circuit board constituting the control device 9 is disposed in the gap. The inner case 4 is provided with a bottom heater 5 at the bottom 4a and a side heater 6 at the side 4b. As the bottom heater 5, an electromagnetic induction coil wound in a donut shape is used. As the side heater 6, a heater in which a heating wire is covered with a heat-resistant member is used. The bottom 4a is provided with a pan bottom temperature sensor 7 composed of a thermistor for detecting the pan bottom temperature.

  As shown in FIG. 1, the main body 2 includes a display panel 8 a that displays a rice cooking time, a timer reservation state, and the like on the front surface 2 a, operation buttons 8 b that are necessary for operating the rice cooker 1, and the like. A display operation unit 8 is provided.

  As shown in FIG. 2, the pan 10 is a relatively deep bottom container into which a predetermined amount of rice to be cooked made of rice and water is put, and is made of, for example, a clad material of aluminum and stainless steel.

  As shown in FIG. 2, the lid 11 includes an inner lid 12 that closes the opening of the pot 10, an outer lid 20 that closes the entire opening of the main body 2, and the like. One end of the lid 11 is pivotally supported on one end of the main body 2 by a pivot 11 </ b> A, and the other end is locked to the other end of the main body 2 by a lock mechanism 21. The lid 11 is provided with a pressure detector 26 that detects the pressure in the pan 10. The pressure detection unit 26 includes a pressure sensor 27 that converts pressure into an electrical signal, and the pressure sensor 27 is provided on the outer lid 20 of the lid body 11.

  The inner lid 12 has a pressure valve 13 at its upper part, a pressure valve opening mechanism 15 for forcibly opening the pressure valve 13, and the pressure in the pot 10 when the pressure in the pot 10 rises to an abnormal pressure of a predetermined value or more. A safety valve V1 for releasing steam to the outside, an inner lid heater (upper heater) 19 for heating the inside of the pan 10 from above, and the like are provided.

  Among these components, the inner lid heater 19 is a heater in which a heating wire similar to the side heater 6 is covered with a heat-resistant member. 2 and 3, the pressure valve 13 includes a valve seat 13 a in which a valve hole 131 having a predetermined diameter is formed, and a metal mounted on the valve seat 13 a so as to close the valve hole 131. The ball 14 is made of a metal and a cover 13b that restricts the movement of the ball 14 and holds it on the valve seat 13a. The ball 14 has a predetermined weight and closes the valve hole 131 by its own weight.

  As shown in FIG. 3, the pressure valve opening mechanism 15 includes a cylinder 15a around which an electromagnetic coil is wound, a plunger 15b that slides in the cylinder 15a by excitation of the electromagnetic coil and moves the ball 14, and the plunger It comprises a spring and an operating rod 15b 'mounted on the tip of 15b. The operating rod 15b 'is supported by a sealing member 15c having elasticity. FIG. 3 shows a state where the electromagnetic coil is excited.

  The pressure valve opening mechanism 15 is controlled by the control device 9. When the electromagnetic coil is excited based on a command from the control device 9, the plunger 15b is drawn into the cylinder 15a. As a result, the force by which the plunger 15 b pushes the ball 14 in the lateral direction is eliminated, so that the ball 14 is placed on the valve seat 13 a by its own weight, and the valve hole 131 is closed by the ball 14. On the other hand, when excitation to the electromagnetic coil is stopped, the plunger 15b protrudes from the cylinder 15a by the force of the spring. As a result, the operating rod 15b 'mounted on the tip of the plunger 15b collides with the ball 14 and pushes the ball 14 in the lateral direction. By this extrusion, the ball 14 is moved from above the valve seat 13a and the valve hole 131 is opened. A steam temperature sensor S for measuring the temperature of steam ejected from the valve hole 131 is attached to the upper part of the pressure valve 13.

  The inner lid 12 is fitted with an inner lid packing 18 on the outer periphery thereof so as to be in contact with the opening of the pan 10 and sealed. As shown in FIG. 4, the inner lid packing 18 has a circular hole 18 </ b> A having a diameter slightly smaller than the diameter of the disk-shaped inner lid 12 and a ring-shaped attachment on the outer peripheral edge of the inner lid 12. It has a mounting portion 18B that is attached via the frame 16, and a seal portion 18C that comes into contact with the opening of the pan 10 and seals the opening, and is composed of a ring having a donut shape as a whole, and has high heat resistance and elasticity. It is formed with the silicon material which has.

  The mounting portion 18B has a concave groove 18B 'in which the ring-shaped mounting frame 16 is mounted, and is formed on the outer periphery of the circular hole 18A. The concave groove 18B 'is erected at a substantially right angle upward from an end portion of the groove bottom 18a on the side of the circular hole 18A and a substantially flat annular groove bottom 18a extending outward from the circular hole 18A. It is comprised by the cylindrical wall 18b and extension part 18a 'extended from the groove bottom part 18a. The cylindrical wall 18b is formed with a hook-like locking claw 18b 'that protrudes outward from its top and has its tip bent downward.

  The seal portion 18C is further extended from the extended portion 18a 'of the groove bottom portion 18a and is formed in a substantially U shape. The U-shaped seal portion 18C is formed by a spring piece portion 18d extending from the extending portion 18a ′ and corresponding to the U-shaped bottom portion, and an elastic seal portion 18e extending from the spring piece portion 18d. . The elastic seal portion 18e has a tip contact portion 181 that contacts the inner wall 10a of the pan 10, and an intermediate contact portion 182 that contacts the curved portion 10b between the inner wall 10a and the pan flange 10c.

  The mounting frame 16 is fitted into the concave groove 18B ′ and contacted with the surface of the groove bottom 18a, a body 16b extending upward from the bottom 16a, and a flat provided on the body 16b. And a ring frame having a donut shape as a whole, and is formed of a resin molded body having high heat resistance and predetermined mechanical strength. The mounting frame 16 is provided with a female screw hole 161 that hangs from the flat surface toward the bottom 16a on the flat surface of the top portion 16c. A locking groove 162 is formed on the flat surface of the top portion 16c. Further, an H-shaped engaging portion 16b 'having a locking groove 163 is formed on the side surface of the body portion 16b, that is, on the surface side of the cylindrical wall 18b. A locking claw 18b 'provided at the top of the cylindrical wall 18b is locked in the locking groove 163 of the H-shaped engaging portion 16b'.

  To attach the inner lid packing 18 to the inner lid 12, first, the ring-shaped attachment frame 16 is attached to the inner lid packing 18. For this mounting, the ring-shaped mounting frame 16 is placed on the top of the cylindrical wall 18b of the inner lid packing 18, and the mounting frame 16 is pressed downward. By this pressing, the cylindrical wall 18b is bent inward by its elastic force, and insertion of the mounting frame 16 downward is allowed. When the bottom portion 16a of the mounting frame 16 is pressed to a position where it contacts the bottom surface of the concave groove 18B ', the restoring force of the cylindrical wall 18b returns to the original position, and the top of the cylindrical wall 18b is locked at this timing. The claw 18b ′ is locked in the engaging groove 163 of the H-shaped engaging portion 16b ′. By this locking, the inner lid packing 18 is fixed to the mounting frame 16. Thereafter, the mounting frame 16 to which the inner lid packing 18 is fixed is brought into contact with the outer peripheral edge of the inner lid 12, and the male screw 17 is screwed into the female screw hole 161 provided in the outer peripheral edge to be fixed.

  According to the inner lid packing 18, the U-shaped seal portion 18C has a spring piece portion 18d corresponding to the U-shaped bottom portion, and an elastic seal extending from the spring piece portion 18d. When the opening of the main body 2 is closed with the lid 11, the elastic sealing portion 18 e of the sealing portion 18 C resists the spring force of the spring piece portion 18 d and the inside of the pot 10. Airtightness is ensured by being in close contact with the wall surface 10a and the curved portion 10b. Therefore, there is almost no steam leakage from the inside of the pan 10, and the loss of heat energy can be suppressed to a minimum, thereby saving energy. Further, since the inner lid packing 18 is fixed to the inner lid 12 with the attachment frame 16 interposed therebetween, the inner lid packing 18 is supported by the attachment frame 16 having a high mechanical strength. Is firmly fixed. Further, since the mounting frame 16 and the inner lid packing 18 can be mounted and removed without using a tool, the old inner lid packing 18 can be easily replaced.

  As shown in FIG. 2, the outer lid 20 is formed of a decorative cover that covers the inner lid 12, the pressure valve 13 attached to the inner lid 12, the pressure valve opening mechanism 15, and the like. The outer lid 20 is provided with a release button 22 for releasing the lock mechanism 21 of the lid 11 at one end, and a mounting hole 24 at the other end on the pivot 11A side. The mounting hole 24 is a bottomed recessed hole having a size that allows the storage cap 25 to be detachably inserted, and is formed in the frame 23 that supports the outer lid 20. In addition, the mounting hole 24 is formed with a mounting hole 24a into which a discharge cylinder 25a of a to-be-stored cap 25 described later is press-fitted. An annular seal member is attached to the mounting hole 24a so as to be in pressure contact with the outer peripheral surface of the discharge cylinder 25a so that the steam in the pan 10 does not leak to the outside.

  For example, the storage cap 25 includes a discharge cylinder 25a that discharges, for example, steam discharged from the pressure valve 13, a vacant chamber 25b that stores a snack of umami components, and a steam discharge port 25c that discharges steam to the outside. It has and the bottom part of the empty room 25b is provided with the toy return valve V2 for returning the stored toy into the pot 10. When the steam is ejected from the pressure valve 13, the rice balls that are umami components are led out from the pot 10 through the pressure valve 13 together with the steam and are stored in the empty chamber 25 b of the storage cap 25. Is done. The rice balls stored in the empty chamber 25b are opened at a predetermined timing, and the return valve V2 is opened and returned to the pan 10 as the negative pressure valve (not shown) provided in the inner lid 12 is opened.

  The pressure detection unit 26 includes a detection hole (not shown) provided in the inner lid 12 and a pressure sensor 27 provided in correspondence with the detection hole. The detection hole and the pressure sensor 27 are included in the pot 10. Are elastically pressed by a cylindrical body 28 having elasticity so that steam generated in the above does not leak to the outside. That is, when the inner lid 12 is attached to the outer lid 20, the cylindrical body 28 connects the detection hole and the pressure sensor 27 by elastic contact so that steam or the like does not leak. The pressure detection unit is not limited to the above, and may be detected by, for example, the amount of change of the inner lid 12, that is, the amount of change when the inner lid 12 is lifted due to the increase in the pressure in the pan 10, or any other arbitrary It may be possible to detect by this method.

  Here, the configuration of the control device 9 will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of a control device provided in the pressure rice cooker of the present embodiment.

  The control device 9 includes a CPU for performing various arithmetic processes, a storage unit including a ROM and a RAM for storing various data, a rice cooking amount determination unit, a valve opening / closing timer in which the opening / closing time of the pressure valve 13 is set, A counter for counting the number of times of opening and closing, a heating control circuit for controlling the heating temperature and heating time in the pan 10, a display panel control circuit for controlling a display screen displayed on the display panel 8a, and a pressure valve opening mechanism 15 are driven. And a pressure valve opening mechanism drive circuit for controlling the opening / closing timing of the pressure valve 13.

  Various commands are input to the control device 9 from the start key 81 and the reservation key 82 of the display operation unit 8. Similarly, detection values are input from the pan bottom temperature sensor 7, the steam temperature sensor S, the pressure sensor 27, and the like. In addition, the bottom heater 5, the side heater 6, the inner lid heater 19, the display panel 8a, the pressure valve opening mechanism 15 and the like are connected to this apparatus.

  Next, with reference mainly to FIGS. 5-8, the rice cooking process performed with the rice cooker 1 of this embodiment is demonstrated. In addition, FIG. 6 is a figure which shows an example of the control pattern of the change in the temperature and pressure in a pan in the rice cooking process of the rice cooker of this embodiment, and a pressure valve and a heating apparatus. FIG. 7 is a pressure curve diagram showing the relationship between the pressure in the pan and the amount of cooked rice in the water absorption process of the rice cooker of the present embodiment. FIG. 8 is a diagram for explaining problems of the heating control method in the conventional rice cooker.

  First, when the start key 81 of the display operation unit 8 is operated and the rice cooking process is started, the control device 9 performs the bottom heater 5, the side heater 6, the inner lid according to the rice cooking program stored in the storage unit in advance. Control of the heater 19 and the pressure valve opening mechanism 15 is started. And while heating the to-be-cooked rice in the pan 10 to predetermined temperature, the water absorption process I which makes a to-be-cooked rice absorb a predetermined amount of water | moisture contents over predetermined temperature and predetermined time, and boiled this to-be-cooked rice to be cooked Start-up heating process II for raising the temperature until heating, boiling maintaining process III for maintaining the cooked rice in a boiling state, and steaming process IV for steaming the cooked food after the boiling maintaining process III are performed (see FIG. 6).

  In the water absorption process I, the control device 9 controls the pressure valve opening mechanism 15 to close the pressure valve 13. In this state, the heating amount of the bottom heater 5, the side heater 6, and the inner lid heater 19 is controlled to bring the inside of the pot 10 to a predetermined water absorption temperature, for example, 60 ° C., so that the rice can absorb water. When the pressure valve 13 is heated in a closed state, the pressure P in the pan 10 rises along a pressure curve corresponding to the amount of cooked rice, as shown in FIG. According to the study by the present inventors, it has been confirmed that when the pressure in the pan 10 increases, the moisture content of rice increases. That is, as shown in FIG. 2, the moisture content at each location is measured with the measurement location in the pan 10 as the bottom portion A near the bottom of the pan, the intermediate portion B higher than the bottom portion A, and the upper portion C above the intermediate portion B. As a result, the average value was increased by 1.0% or more compared with the case where the pressure was not increased.

  Thus, in the water absorption process I of the rice cooker 1 of this embodiment, since the inside of the pan 10 is heated to a predetermined temperature and the internal pressure is increased and water is absorbed into the rice, uneven water absorption is generated. It is possible to effectively and efficiently absorb sufficient water to the rice. This is considered to be because pressure is applied to water and rice by pressurizing the inside of the pan 10, and this pressure makes it easy for water to pass through the rice cell wall, so that more water is absorbed by the starch of rice. . Also, when pressure is applied to the rice, a small crack enters the rice, water penetrates into the rice from there, water is supplied to the starch in the center of the rice through the gap between the rice cell walls, It is thought that the moisture content increases.

  Moreover, in the water absorption process I of the rice cooker 1, the amount of rice cooking in the pan 10 is calculated | required from the pressure value P in the pan 10. FIG. This will be described with reference to FIG. When the amount of rice cooking is small, the relationship between the pressure in the pot 10 and the amount of rice cooking in the water absorption process I rises steeply from the beginning as shown by the pressure curve X1, becomes substantially constant at a high pressure value P3, and is saturated. Further, when the amount of cooked rice is large, as shown in the pressure curve X3, the rise is dull and the pressure value P1 becomes a substantially constant value and becomes saturated. Furthermore, when the amount of cooked rice is an intermediate amount, the pressure curve X2 is located between the pressure curves X1 and X3, and becomes a substantially constant value and becomes saturated at the intermediate pressure value P2.

  In addition, the above-mentioned pressure value P is the range of 1.05-1.18 atmosphere, and the amount of rice cooking of each pressure curve X1-X3 is 0.5 cup for the curve X1, and 3.3 cup for the curve X2. The curve X3 is 5.5 cups, and the amount of cooked rice is small, medium, and large in order.

  According to the study by the present inventors, it has been found that the pressure value and the amount of cooked rice correspond to each pressure curve X1 to X3 at a stable time point (when it becomes a substantially constant value) on a one-to-one basis. For this reason, the control apparatus 9 detects the pressure in the pan 10 in the water absorption process I with the pressure sensor 27, inputs the pressure value detected with the pressure sensor 27 into the rice cooking determination unit, and calculates the amount of rice cooked in the pan 10. It comes to judge. In addition, the relationship between the pressure in the pan 10 and the amount of cooked rice is stored in advance in the storage unit as described above, and in the rice cooking determination unit, the detected pressure value and the cooked rice amount data stored in the storage unit are stored. The amount of cooked rice is determined by collation. Such determination of the amount of cooked rice is to determine the amount of cooked rice without being affected by the initial water temperature, and therefore, a more accurate determination can be made than the method of determining the amount of cooked rice based on a change in temperature.

  In the next rising heating process II, the heating amount of the heating device is controlled based on the amount of rice cooking. In this step, the pressure in the pot 10 is increased to, for example, 1.2 atmospheres.

  Further, in the boiling maintenance step III, the pressure valve 13 is forcibly opened once or a plurality of times to reduce the pressure in the boiling pot 10 at a stroke so as to be close to the atmospheric pressure. The opening of the pressure valve 13 causes a bumping phenomenon in the pan 10, and the rice is vigorously stirred. In addition, when the pressure valve 13 is opened, the umami component generated in the pan 10 is temporarily stored in the storage cap 25 through the pressure valve 13. The rice balls stored in the storage cap 25 are returned to the pot 10 by opening the return valve V2 at a predetermined timing.

  The rice cooker 1 of this embodiment is characterized by the control operation of the heating device in the rising heating process II and the boiling maintaining process III. Hereinafter, this point will be described, but prior to that, in order to facilitate understanding of the control operation of the heating device of the present embodiment, a conventional problem will be described with reference to FIG.

  8 (a) to 8 (c) are diagrams showing the relationship between time (relative time of each process) and temperature (pot bottom temperature) in the rice cooking process, and FIG. 8 (a) shows a small amount of rice cooking. 8 (b) shows a case where the amount of cooked rice is medium, and FIG. 8 (c) shows a case where the amount of cooked rice is large. Here, when the amount of rice to be cooked is 1 cup (1 go), the amount of cooked rice is small, when the amount of rice is 3 cups (3 go), the amount of rice cooked is medium, and the amount of rice is 5 The amount of cooked rice is 5 cups (5.5 go). Moreover, Fig.8 (a)-FIG.8 (c) make electric power (starting heating electric power) given to a heating device in the case of the start-up heating process II irrespective of the amount of rice cooking to be constant electric power, and also according to the amount of rice cooking. It shows the case where the power (boiling maintenance power) applied to the heating device during the boiling maintenance step III is also constant power. The rising heating power and the boiling maintenance power are different in magnitude.

  In the start-up heating process II, because heating is performed at a constant power regardless of the amount of cooked rice, as shown in FIG. 8, when the amount of cooked rice is small, the time to reach the boiling state is shortened, and the amount of cooked rice is large It takes longer to reach the boiling state. Whether or not the boiling state has been reached can be determined based on the temperature measured by the steam temperature sensor S (see FIGS. 3 and 5). For example, the temperature measured by the steam temperature sensor S is 74 ° C. It can be determined that the boiling state has been reached. Further, when the temperature measured by the steam temperature sensor S reaches 74 ° C., the process proceeds from the rising heating process II to the boiling maintaining process III.

  If the time required for the start-up heating process II is short as in the case of FIG. 8A, the process proceeds to the boiling maintenance process III before water is sufficiently absorbed by the rice. In this case, when the boiling maintenance process III is started, the amount of water becomes relatively large, and the time required for the boiling maintenance process III becomes long. In the case shown in FIG. 8A, the time b required for the boiling maintenance step III is longer than the time a required for the start-up heating step II (a <b). In addition, the completion | finish judgment of the boiling maintenance process III is judged by the temperature measured with the pan bottom temperature sensor 7 (refer FIG. 2, FIG. 5). For example, when the temperature measured by the pan bottom temperature sensor 7 reaches 120 ° C., it is determined that the water in the pan 10 has been drowned and the forced dry-up has been completed, so the boiling maintenance process III is terminated at that temperature, It is decided to move to the steaming process IV.

  In the case of Fig.8 (a), when the moisture content of the rice in the pan 10 after the end of the rice cooking process was examined, the average value was about 64%, and the rice state gave a solid impression. .

  On the other hand, when the time required for the start-up heating step II is long as in the case of FIG. 8C, the amount of water absorbed by the rice increases. In this case, when the boiling maintenance process III is started, the amount of water becomes relatively small, and the time required for the boiling maintenance process III is shortened. 8A, the time b required for the boiling maintenance process III is shorter than the time a required for the start-up heating process II (a> b).

  In the case of FIG.8 (c), when the moisture content of the rice in the pan 10 after completion | finish of a rice cooking process was investigated, the average value was about 62%. However, there was a large difference in the moisture content of the rice between the surface portion of the cooked rice after cooking and the rice in the peripheral portion of the pan 10 and the rice in the central portion of the pan 10. As for the state of rice, the rice in the surface part of the cooked rice after cooking and the peripheral part of the pan 10 gives a sticky impression, and the rice in the center of the pan 10 gives a prickly impression. Met.

  In addition, when the amount of cooked rice is medium as shown in FIG. 8B, the time a required for the start-up heating step II is the time between when the amount of cooked rice is small and when it is large. In the case shown in FIG. 8B, the time a required for the start-up heating process II and the time b required for the boiling maintenance process III are approximately the same (a = b). In the case of FIG. 8 (b), when the moisture content of the rice in the pan 10 after the rice cooking process was examined, the average value was about 62.5%, and the impression that the rice was sticky or pattered. It was not something to give, it was delicious and it was ideal.

  As described above, if the same cooking method is used despite the difference in the amount of cooked rice, there is a case where a difference in the amount of cooked rice is produced depending on the amount of cooked rice and a delicious cooked rice cannot be obtained. Then, based on the above result, various examinations were performed regarding preferable heating control of the rice cooker 1, and the following knowledge was obtained.

  First, in order to eliminate unevenness in cooking due to the difference in the amount of cooked rice, it was found that it is preferable that the total time required for the start-up heating process II and the boiling maintenance process III be the same in any case of cooked rice . And in any rice cooking amount, the time a required for the start-up heating process II and the time b required for the boiling maintenance process III have a certain relationship (in other words, in any rice cooking amount, It was found that performing the rice cooking step so that the ratio of time a and time b is substantially the same) is preferable in order to eliminate uneven cooking.

  In addition, in order to make the same delicious cooking in any amount of cooked rice, in the start-up heating process II, in the case of any cooked rice amount, it should be brought to a boiled state rapidly and boiled very slowly It turned out to be unpreferable. And the preferable time of the start-up heating process II is time when rice can absorb water moderately, and it turned out that this is the same also in any rice cooking amount. In addition, this time is calculated | required by experiment, for example. Furthermore, in any rice cooking amount, it is preferable that the time a required for the start-up heating step, which is determined as the time during which water can be appropriately absorbed, and the time b required for the boiling maintenance step III are approximately the same. I understood it.

  Therefore, in the present embodiment, a time (predetermined time) for the rice to absorb water appropriately in the start-up heating step II is obtained, and this time is set as the time required for the start-up heating step II. In addition, this predetermined time is the same time and fixed value in any rice cooking amount. And in any rice cooking amount, the predetermined time obtained previously is the time a required for the start-up heating step II, and the time b required for the boiling maintenance step III is the time a required for the start-up heating step II The rice cooking process is performed while controlling the heating amount of the heating device so as to be substantially the same.

  For example, the temperature change pattern as shown in FIG. 8 (b) is an ideal temperature change, and in the rice cooker 1, the temperature change pattern as shown in FIG. Thus, the control device 9 controls the amount of heating given to the cooked rice in the pan 10 by the heating device (the bottom heater 5, the side heater 6, and the inner lid heater 19). And by this, in the case of any rice cooking amount, it can be made the delicious cooking which has the same taste. In addition, according to the rice cooking method of this embodiment, the moisture content of the cooked rice is about 62.5% on average for any rice cooking amount, and variation in the moisture content of rice in the pan 10 can be suppressed. .

  When the start-up heating process II and the boiling maintenance process III described above are completed, the process proceeds to the heat retaining process in response to a command from the display operation unit 8 or automatically. In this heat insulation process, the control device 9 keeps the inside of the pan 10 at a predetermined time and at a predetermined temperature. In this time zone, the control device 9 intermittently controls on / off of the bottom heater 5, the side heater 6, and the inner lid heater 19 to control the temperature at a predetermined temperature, for example, 70 ° C. or higher. By this heat retention control, the dew condensation on the inner wall of the pan 10 is reduced and the heat is kept at an optimum temperature.

  In addition, the electric rice cooker of this invention is not the meaning limited to the structure of embodiment shown above. That is, various modifications can be made without departing from the object of the present invention.

  For example, in embodiment shown above, it was set as the structure which detects the pressure in the pan 10 with the pressure sensor 27 about the amount of rice cooking in the pan 10, and detects the amount of rice cooking using the detected pressure. However, the present invention is not limited to this configuration. That is, for example, the amount of cooked rice in the pan may be determined by providing a weight meter in the rice cooker, or for example, the configuration of determining the amount of cooked rice using the temperature change when heated in the water absorption process. I do not care. Furthermore, it is good also as a structure (for example, providing a rice cooking amount input button) which a user inputs about rice cooking amount.

  In addition, in embodiment shown above, although the case where an electric rice cooker was a pressure type rice cooker was shown, the application range of this invention is not necessarily limited to a pressure type rice cooker, normal non- It can also be applied to pressure rice cookers.

These are the front views of the pressure type rice cooker which concerns on embodiment of this invention. These are the longitudinal cross-sectional views of the pressure type rice cooker of FIG. FIG. 3 is an enlarged view of the pressure valve opening mechanism of FIG. 2. FIG. 3 is an enlarged view of a portion X in FIG. 2. These are block diagrams which show the structure of the control apparatus with which the pressure type rice cooker of this embodiment is provided. These are figures which show an example of the control pattern with the change in the temperature and pressure in a pan in the rice cooking process of the rice cooker of this embodiment, and a pressure valve and a heating apparatus. These are the pressure-curve figures which showed the relationship between the pressure in a pan in the water absorption process of the rice cooker of this embodiment, and the amount of rice cooking. These are the figures for demonstrating the problem of the heating control method in the conventional rice cooker.

Explanation of symbols

1 (Pressure type) rice cooker (electric rice cooker)
2 (Rice cooker) body 5 Bottom heater (part of heating device)
6 Side heater (part of heating device)
DESCRIPTION OF SYMBOLS 9 Control apparatus 10 Pan 11 Cover body 13 Pressure valve 15 Pressure valve opening mechanism 19 Inner cover heater (a part of heating apparatus)
26 Pressure detector

Claims (7)

A pan in which to-be-cooked food containing water and rice is stored;
A rice cooker body having an opening in which the pan is accommodated;
A lid that closes the opening;
A heating device for heating the cooked rice in the pan;
A control device for controlling the heating device to perform a rice cooking process, and an electric rice cooker comprising:
The rice cooking step includes a water absorption step for absorbing water into the rice, a rising heating step for heating the cooked rice absorbed in the water absorption step until boiling, and a boiling for maintaining the cooked rice in a boiling state. A maintenance process,
The control device is configured such that the first time required for the start-up heating step is a predetermined time, and the first time and the boiling maintaining step, regardless of the amount of rice cooked in the pan. The electric rice cooker is characterized in that the heating amount of the heating device is controlled in accordance with the amount of rice cooked in the pan so that the second time required for the heating is in a certain relationship.   The electric rice cooker according to claim 1, wherein the predetermined relationship is a relationship in which the first time and the second time are substantially the same. The control device includes a storage unit that stores the rice cooking amount and the heating control pattern in association with each other,
The said control apparatus reads the said heating control pattern according to the amount of rice cooking in the said pan from the said memory | storage part, and controls the said heating apparatus, The electric rice cooker of Claim 1 or 2 characterized by the above-mentioned. The lid body is provided with a pressure valve for adjusting the pressure in the pan, and a pressure valve opening mechanism for controlling the pressure valve,
The said control apparatus controls the said heating apparatus and the said valve opening / closing mechanism, and performs the said rice cooking process, The electric rice cooker in any one of Claim 1 to 3 characterized by the above-mentioned. A pressure detection unit that detects the pressure in the pan, and a rice cooking amount determination unit that inputs a detection value of the pressure detection unit and determines the amount of rice cooking in the pan;
In the water absorption step, the control device raises the temperature in the pan to a predetermined temperature by the heating device after sealing the pan, detects the pressure value in the pan by the pressure detection unit, and detects the pressure The electric rice cooker according to any one of claims 1 to 4, wherein a value is input to the rice cooking amount determination unit to determine the amount of rice cooking in the pan. It is a rice cooking method for storing a rice to be cooked containing water and rice in a pan and performing a rice cooking process,
The rice cooking step includes a water absorption step for absorbing water into the rice, a rising heating step for heating the cooked rice absorbed in the water absorption step until boiling, and a boiling for maintaining the cooked rice in a boiling state. A maintenance process,
Even when the amount of cooked rice in the pan is any amount, the first time required for the rising heating step is a predetermined time, and the second time required for the first time and the boiling maintenance step The rice cooking method characterized by performing rice cooking, controlling the amount of heating according to the amount of rice cooking in the said pan so that time may become a fixed relationship.   The rice cooking method according to claim 6, wherein the certain relationship is a relationship in which the first time and the second time are substantially the same.

Images