JP2004057556A - Pressure rice cooker - Google Patents

Pressure rice cooker Download PDF

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Publication number
JP2004057556A
JP2004057556A JP2002221231A JP2002221231A JP2004057556A JP 2004057556 A JP2004057556 A JP 2004057556A JP 2002221231 A JP2002221231 A JP 2002221231A JP 2002221231 A JP2002221231 A JP 2002221231A JP 2004057556 A JP2004057556 A JP 2004057556A
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Japan
Prior art keywords
pressure
stepping motor
pressing
pot
time
Prior art date
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Granted
Application number
JP2002221231A
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Japanese (ja)
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JP3935019B2 (en
Inventor
Tokuji Betsushi
Kenji Hamada
Hidetaka Osumi
Sadamu Utsunomiya
Takeshi Yamane
別枝 篤司
大隅 英孝
宇都宮 定
山根 健
濱田 憲司
Original Assignee
Zojirushi Corp
象印マホービン株式会社
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Priority to JP2002221231A priority Critical patent/JP3935019B2/en
Publication of JP2004057556A publication Critical patent/JP2004057556A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure rice cooker capable of minutely adjusting a pressure applied at rice cooking. <P>SOLUTION: The pressure rice cooker is provided with an inner pot 2, a main body 3, a cover body 4, an induction heating coil 6 (heating means), an exhaust port 20c for exhausting steam in the inner pot 2, a pressure sensor 13 (pressure detecting means), a closing valve 20b for closing the exhaust port 20c, a pressing part 21b for providing the closing valve 20b with a pressing force via a spring 21g, an arm part 22 (pressing part moving means) for moving the pressing part 21b in a closing direction toward a closing position or in an opening direction toward an opening position, a pressure adjusting device 15 provided with a stepping motor 23 for driving the arm part 22 in a normal rotation or in a reverse rotation and a microcomputer 8 (control means) for increasing or decreasing a pressure in the inner pot 2 based on a signal from the pressure sensor 13 at pressure rice cooking by driving the stepping motor 23 of the pressure adjusting device 15 in the normal rotation direction or in the reverse rotation direction to move the pressing part 21b in the closing direction or in the opening direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to home and commercial pressure cookers.
[0002]
[Prior art]
As a pressure cooker for cooking at a pressure higher than the atmospheric pressure, there is known a pressure cooker in which a pressure regulator as a pressure mechanism is provided in a steam discharge path formed inside a lid closing an inner pot. The pressure regulator includes a steam discharge path communicating with the inner pot, a pressure regulating ball disposed in the steam discharge path, and a solenoid that is a driving means of the pressure regulating ball. Before rice cooking, at the beginning of rice cooking, and after rice cooking, the pressure regulator presses a pressure regulating ball by a solenoid, retracts from a steam discharge path, and communicates the inside of the inner pot with the outside of the lid (open state). It has become. In addition, during pressure cooking, the steam discharge path is closed by the weight of the ball to increase the internal pressure of the inner pot and pressure is applied.On the other hand, when the inner pressure of the inner pot exceeds a predetermined pressure, the steam in the inner pot is discharged. The pressure regulating ball is raised, and is discharged to the outside through a vapor hole provided in the lid via a vapor discharge path (pressurized state).
[0003]
[Problems to be solved by the invention]
However, the rice cooker has a problem that only a constant pressure can be applied during rice cooking, and fine pressure adjustment cannot be performed.
[0004]
Therefore, an object of the present invention is to provide a pressure cooker capable of finely adjusting the pressure applied during rice cooking.
[0005]
[Means for Solving the Problems]
The present invention, as means for solving the above problems,
Inner pot,
A main body containing the inner pot;
A lid that is attached to the main body so as to be openable and closable, and seals the inner pot;
Heating means for heating the inner pot,
An exhaust port for discharging steam in the inner pan provided on the lid,
Pressure detection means for detecting the pressure in the inner pot,
A closing valve for closing the exhaust port, a pressing portion for applying a pressing force to the closing valve via a spring having a predetermined elastic force, and a pressing portion movably provided between a closing position and an opening position; A pressing unit moving means for moving in the closing direction toward the closing position or the opening direction toward the opening position, and a pressure regulating device having a forward / reverse rotatable stepping motor for driving the pressing unit moving means,
At the time of pressure cooked rice, based on a signal from the pressure detecting means, by rotating the stepping motor of the pressure regulating device in the normal direction or the reverse direction to move the pressing portion in the closing direction or the opening direction, It is provided with control means for increasing or decreasing the pressure in the inner pan.
[0006]
In the above invention, at the time of pressure cooking, the control means outputs a drive signal to the stepping motor based on the pressure in the inner pot detected by the pressure detection means. When the stepping motor is driven to rotate in the normal rotation direction in response to this drive signal, the pressing portion moves in the closing direction. At this time, the pressing portion applies a pressing force via a spring to the closing valve that closes the exhaust port to pressurize the pressure in the inner pan. On the other hand, when the stepping motor is driven to rotate in the reverse direction, the pressing portion moves in the opening direction. At this time, the pressing portion is pushed upward by the pressing force of the spring. As a result, the pressing force of the spring applied to the closing valve is reduced, and the pressure in the inner pan is reduced. Thereby, the pressure in the inner pan can be varied.
[0007]
The control means includes:
Set the upper pressure limit and lower pressure limit,
When the pressure value detected by the pressure detecting means is equal to or less than the lower pressure limit, the stepping motor is driven to rotate in the normal rotation direction,
When the pressure value is equal to or higher than the upper pressure limit, the stepping motor is driven to rotate in a reverse direction,
When the pressure value is equal to or higher than the lower pressure limit and equal to or lower than the upper pressure limit, the stepping motor is preferably turned off. Thereby, the pressure in the inner pan is regulated to be equal to or higher than the lower pressure limit and equal to or lower than the upper pressure limit. When the pressure is within this pressure range, the stepping motor is turned off, so that the pressure in the inner pan is maintained at an appropriate pressure value.
[0008]
Further, it is preferable that the pressure upper limit value and the pressure lower limit value can be set arbitrarily. Thereby, the cooking method can be changed.
[0009]
The control means increases the rotation speed of the stepping motor when the pressure difference between the pressure value detected by the pressure detection means and the pressure upper limit value or the pressure lower limit value is equal to or greater than a predetermined pressure difference. When the difference is less than the predetermined pressure difference, it is preferable to reduce the rotation speed of the stepping motor. Accordingly, when the pressure difference is large (when the pressure difference is equal to or larger than the predetermined pressure difference), the pressure can be quickly increased or decreased to the set pressure. In addition, when the pressure difference is small, fine pressure adjustment becomes possible near the set pressure.
[0010]
When reducing the pressure in the inner pot, the control means may rotate the stepping motor in a reverse direction for a predetermined ON time, and then turn off the stepping motor for a predetermined OFF time. preferable. Thereby, the pressure in the inner pan can be reduced stepwise.
[0011]
At this time, it is preferable that the ON time and the OFF time are set according to the pressure in the inner pot. For example, when the pressure in the inner pot is high, if the ON time is set to a short time of 20 ms, the amount of steam discharged can be reduced. When the pressure in the inner pan is low, the on-time is set to 500 ms, and when the off-time is set to 1 s, the pressure in the inner pan can be quickly reduced.
[0012]
Further, it is preferable that the on-time and the off-time are individually set in accordance with each rice cooking menu, each process, or rice cooking capacity.
[0013]
A clock pulse output circuit that outputs a clock pulse having a predetermined frequency to the control unit; and a control unit that is turned on when the pressing unit moving unit contacts the pressing unit when the pressing unit is moved to the open position. A micro switch that outputs a signal to
The control means counts the number of clock pulses output while the stepping motor is rotationally driven in a forward direction or a reverse direction from a time point when the microswitch is turned on. When the stepping motor is driven to rotate in the reverse direction, the counted number of clock pulses is preferably subtracted when the stepping motor is driven to rotate in the reverse direction. Thereby, the position of the motor position of the stepping motor can be detected with reference to the motor position of the stepping motor when the micro switch is turned on.
[0014]
When the micro switch is turned on, the control means sets the motor position of the stepping motor to a zero point, rotates the stepping motor in a normal rotation direction, and counts the counted value to a positive first predetermined number. It is preferable to set the motor position of the stepping motor at the time of becoming as the MAX point. At this time, the operation range of the stepping motor can be defined between the zero point and the MAX point. When the micro switch is turned on, the pressing portion is provided so as to be located at the open position. Further, when the stepping motor is driven to rotate in the normal rotation direction so that the motor position of the stepping motor is located at the MAX point, the pressing portion is provided so as to be located at the closing position.
[0015]
At this time, it is preferable that the control unit turns off the stepping motor when the count value becomes 0 corresponding to the zero point or the positive first predetermined number corresponding to the MAX point.
[0016]
The control means may turn off the stepping motor when the count value reaches the first positive predetermined number or the negative second predetermined number corresponding to the MAX point.
[0017]
It is preferable that the pressing portion moving means is an arm portion rotatably provided in conjunction with an output shaft of the stepping motor and arranged above the pressing portion.
[0018]
The control means preferably turns off the stepping motor for a predetermined time when changing the rotation direction of the stepping motor to the opposite direction. By turning off the stepping motor for a predetermined time, slipping when the stepping motor starts reverse rotation can be prevented, and accurate operation of the pressure regulator can be realized.
[0019]
It is preferable that the control unit lowers the initial rotation speed of the stepping motor when the rotation driving of the stepping motor is started or when the rotation direction of the stepping motor is changed to the opposite direction. As a result, a larger torque can be obtained as compared with the case where the motor is driven to rotate at a normal rotation speed.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0021]
(1st Embodiment)
FIG. 1 shows a pressure cooker 1 according to a first embodiment of the present invention. The pressure cooker 1 includes an inner pot 2, a main body 3, and a lid 4.
[0022]
The inner pot 2 is formed by coating an outer surface of a pot base material made of aluminum or the like having a high thermal conductivity with a ferromagnetic material that is electromagnetically heated by an eddy current generated when a high-frequency current is supplied to an induction heating coil 6 described later. Or joined together.
[0023]
The main body 3 includes a protective frame 5 made of a non-conductive material for accommodating the inner pan 2 inside a body 3 a having a bottomed cylindrical shape. Between the body 3a and the protective frame 5, an induction heating coil 6 as a heating means, an inner pot temperature sensor 7 and a microcomputer 8 as a control means are arranged.
[0024]
The induction heating coil 6 is disposed on the lower surface of the protection frame 5 and is configured to heat the inner pot 2 by electromagnetic induction when a high-frequency current is applied.
[0025]
The inner pan temperature sensor 7 detects the temperature of the inner pan 2, is disposed at the bottom of the protective frame 5, and has a detecting portion at the tip thereof through a through hole provided in the protective frame 5. And outputs the temperature of the inner pan 2 to the microcomputer 8.
[0026]
The lid 4 closes the openings of the inner pot 2 and the main body 3 so as to be openable, and includes an upper lid plate 4a and a lower lid plate 4b. On the inner pot 2 side of the lid 4, a heat radiating plate 9, a lid heater 10, and an inner lid 11 are provided. Further, inside the lid 4, a lid temperature sensor 12, a pressure sensor 13, a relief valve 14, and a pressure regulator 15 are arranged.
[0027]
The lid temperature sensor 12 detects the temperature in the inner pan 2 and outputs the detected temperature to the microcomputer 8.
[0028]
The pressure sensor 13 is disposed so that a detection unit thereof faces the inside of the inner pot 2, detects a pressure in the inner pot 2, and outputs a voltage value according to the detected pressure to the microcomputer 8. Is what you do.
[0029]
The relief valve 14 has a well-known configuration including a pressure regulating ball 16 which is arranged from above an opening 14a communicating with the inner pot 2 and closes the opening 14a by its own weight. The pressure adjusting ball 16 is a metal sphere coated with polypropylene. In addition, a steam discharge path 17 is formed inside the lid 4 and communicates with the outside of the lid 4 through the opening 14 a and the vapor port 4 c of the lid 4. At the time of cooking rice, the pressure regulating ball 16 closes the opening 14a by its own weight, while the internal pressure of the inner pot 2 is, for example, 0.52 kg / cm. 2 When the pressure exceeds (1.5 atm), the steam in the inner pan 2 rises, and the steam in the inner pan 2 is discharged to the outside. Thereby, when the inside of the inner pot 2 becomes abnormally high pressure, the internal pressure is released.
[0030]
As shown in FIGS. 2 to 4, the pressure regulating device 15 includes a closing valve section 20, a closing valve pressing section 21, an arm section 22 (pressing section moving means), and a stepping motor 23.
[0031]
The closing valve section 20 includes a closing valve housing section 20a and a closing valve 20b. The closing valve accommodating portion 20a is fitted from below into a mounting hole 11a provided in the inner lid 11, and is engaged with and attached to the lower surface of the edge of the mounting hole 11a. An exhaust port 20c is formed inside the closing valve accommodating portion 20a. A recess 20d for accommodating the closing valve 20b is formed inside the closing valve housing portion 20a. At the upper end of the closing valve accommodating portion 20a, three locking claws 20e for locking a later-described case member 21a of the closing valve pressing portion 21 are formed.
[0032]
The closing valve 20b is vertically movably disposed inside the recess 20d of the closing valve housing portion 20a. Four claws 20f for locking the lower end of the spring 21g are provided on the outer periphery of the closing valve 20b. A shaft portion 20g is provided on the upper surface of the closing valve 20b.
[0033]
The closing valve pressing portion 21 includes a case member 21a and a pressing portion 21b. The case member 21a has a substantially cylindrical shape with an open lower surface, and an upper surface thereof has an insertion hole 21c through which the upper portion of the pressing portion 21b is inserted. The case member 21a is disposed from above the closing valve portion 20, and a locking claw 21d (shown in FIG. 2) provided on an inner surface of a side wall of the case member 21a is engaged with a locking claw 20e of the closing valve housing portion 20a. By being combined, it is attached and fixed to the upper surface of the inner lid 11. The pressing portion 21b has a cylindrical shape, and is provided with a cylindrical insertion portion 21e extending downward from the lower surface thereof. Further, three guide pieces 21f projecting outward are formed below the pressing portion 21b. The pressing portion 21b is arranged inside the case member 21a, and each guide piece 21f of the pressing portion 21b is slidably provided in a guide groove 20h formed on the inner surface of the side wall of the case member 21a. The shaft portion 20g of the closing valve 20b is inserted inside the insertion portion 21e of the pressing portion 21b. Accordingly, the pressing portion 21b is vertically movable with its upper part protruding upward from the insertion hole 21c of the case member 21a. A spring 21g is provided between the lower surface of the pressing portion 21b and the upper surface of the closing valve 20b. The spring 21g presses the closing valve 20b downward to close the exhaust port 20c.
[0034]
The periphery of the closing valve pressing portion 21 is covered with an elastic cap 24 made of elastic rubber or the like. The folded collar portion 24a formed at the lower portion of the elastic cap 24 is sandwiched between the heat sink 9 and the inner lid 11. At the top of the elastic cap 24, a disk-shaped thick portion 24b is integrally formed. A plurality of flow ports 24c are formed in the shoulder of the elastic cap 24.
[0035]
The arm portion 22 (pressing portion moving means) has a ring-shaped portion 22a formed at the center thereof, and an L-shaped mounting portion 22b is provided on the lower surface on both sides of the ring-shaped portion 22a. Both ends of the pressing bar 22c are supported by the mounting portion 22b. The pressing bar 22c has a disc-shaped portion 22d at an intermediate portion thereof. On one side of the ring-shaped portion 22a, a protruding portion 22e protruding outward is provided. The protrusion 22e is for turning on the microswitch 26 when the arm 22 rotates counterclockwise as described later. An arc-shaped rack 22f that meshes with a pinion gear 23b of the stepping motor 23, which will be described later, is provided at the tip of the arm 22. The fulcrum portion 22g of the arm portion 22 has a disk shape, and a hole 22h is formed in the center thereof. A fixed shaft 22i fixed to the arm mounting portion 25a of the motor stay 25 is fitted into the hole 22h of the fulcrum portion 22g. The ring-shaped part 22a of the arm part 22 is arranged so as to be located above the elastic cap 24, and the arm part 22 is attached rotatably about a fixed shaft 22i. The disc-shaped portion 22d of the pressing bar 22c is in contact with or fixed to the upper surface of the thick portion 24b on the top of the elastic cap 24.
[0036]
The stepping motor 23 is driven to rotate in both directions (forward direction or reverse direction) as shown by an arrow P in FIG. The stepping motor 23 is fixed to a motor stay 25, and an output shaft 23a of the stepping motor 23 is provided with a pinion gear 23b fixed integrally with the output shaft 23a. The pinion gear 23b is arranged so as to mesh with the rack 22f of the arm portion 22. When the stepping motor 23 is driven to rotate in the normal direction or the reverse direction, the arm portion 22 is moved to an arrow Q in FIG. Are driven to rotate clockwise or counterclockwise as indicated by. Thereby, the pressing portion 21b moves in the closing direction or the opening direction along the vertical direction indicated by the arrow R in FIG.
[0037]
Further, the stepping motor 23 is connected to the microcomputer 8 via a peripheral circuit 40 shown in FIG. The stepping motor 23 receives an on / off drive signal from the ports p1 to p4 of the microcomputer 8 and is driven according to the drive signal.
[0038]
As shown in FIG. 4, the motor stay 25 is attached and fixed to the lower cover plate 4b with screws 25b. A micro switch 26 is provided near the center of the motor stay 25 so as to be positioned above the protrusion 22e of the arm 22 with the arm 22 attached to the motor stay 25. When the arm 22 is rotated in the counterclockwise direction and the pressing portion 21b is located at an open position (upper end in the vertical direction) to be described later, the microswitch 26 comes into contact with the protrusion 22e of the arm 22. Are arranged so as to be turned on.
[0039]
The closing valve 20b is pressed downward by a spring 21g to close the exhaust port 20c. Further, inside the cover 4, a steam discharge path 18 is formed, which communicates with the outside of the cover 4 through the exhaust port 20c and the steam port 4c of the cover 4. When the internal pressure of the inner pot 2 rises during rice cooking, the closing valve 20b is pushed up by the steam in the inner pot 2 against the elastic force of the spring 21g, whereby the steam in the inner pot 2 passes through the steam discharge path 18. It is designed to be discharged to the outside.
[0040]
An operation panel 19 shown in FIG. 5 is provided on the upper surface of the lid 4. In the operation panel 19, a plurality of switches 31 to 35 for inputting rice cooking conditions are provided around a display panel 30 of a liquid crystal display system provided in the center.
[0041]
The switches 31 to 35 execute a reserved rice menu or a germinated brown rice rice menu, and a rice cook switch 31 for pressing when a reheating function is to be performed during execution of a warming function, and a desired rice cooking menu or a reserved rice menu. A menu switch 32 for selection, a release switch 33 for pressing when it is desired to end all operations including the rice cooking operation and the reserved rice cooking operation and to be in a standby state, a heat retention switch 34 for pressing when performing a heat retention function, A sleep insulation switch 35 to be pressed when the user wants to change to the sleep insulation function and execute it. An LED (not shown) is provided at the back of each of the switches 31, 34, and 35, so that the switches 31, 34, and 35 can be lit or blinked.
[0042]
In the center of the display panel 30, a numerical value display unit 30a capable of displaying a time of 24 hours, a time display unit 30b indicating a unit such as a heat retention time, and a minute display unit 30c indicating a unit such as a remaining time of the rice cooking operation. Is provided. In addition, a triangular display for indicating the hardness of the rice in the rice cooked rice menu “normal”, “soft”, “warm”, and “white rice quick” is provided on the upper part of the display panel 30; , "Curry", "lunch", "sushi", "koge", "cooked", "porridge", and a menu display portion for indicating "kokowa". I have. Above the numerical display 30a, a reheat display 30e indicating that reheating is being performed is provided. In addition, a menu display at the bottom of the display panel 30 for indicating that four types of healthy rice cooking menus, “divided rice”, “brown rice”, “active brown rice”, and “germinated brown rice” are selected. A part 30f is provided.
[0043]
Below the menu display section 30f, there is provided a pictogram display section 30g for displaying the pressure in the inner pot 2 at the time of pressure cooking, which will be described later, stepwise. The pictogram display section 30g increases or decreases the display number of the four pictographs 30h provided on both sides in accordance with the pressure in the inner pan 2 detected by the pressure sensor 13. For example, when the pressure in the inner pan 2 is low, only one pict 30h on both sides of the central portion is displayed, and when an abnormally high pressure state occurs due to a failure of the pressure regulator 15, the relief valve 14, and the like, all four are displayed. The pictogram 30h is displayed. This allows the user to determine the pressure state in the inner pot 2, thereby preventing the user from inadvertently opening the lid 4.
[0044]
The microcomputer 8 sequentially executes the respective steps of a preheating step, a rice cooking step, a washing step, and a heat retaining step in accordance with a stored program in response to inputs from the temperature sensors 7, 12 and the pressure sensor 13, and the like, and performs the rice cooking operation. Is what you do. The microcomputer 8 performs pressure regulation control (pressure rice cooking) in accordance with an input from the pressure sensor 13 in accordance with a stored program in the rice cooking step and the rice drying step during the rice cooking operation. FIG. 7 shows a data table 50 stored in the microcomputer 8 used for this control. The data table 50 includes a detected pressure value of the pressure sensor 13, a voltage value output from the pressure sensor 13, and an AD value corresponding to the voltage value. The AD value is displayed in hexadecimal (HEX).
[0045]
Next, a driving method in which the microcomputer 8 drives the stepping motor 23 will be described. In the present embodiment, the microcomputer 8 drives the stepping motor 23 by a 1-2-phase excitation method. The 1-2-phase excitation method is an excitation method in which one-phase excitation and two-phase excitation are alternately performed. FIGS. 8A and 8B show drive signals in the 1-2-phase excitation method output by the microcomputer 8. FIG. The microcomputer 8 is connected to a clock pulse output circuit 42 (shown in FIG. 6) provided inside or outside the microcomputer 8, and the clock pulse output circuit 42 supplies a clock pulse a having a predetermined frequency (in this embodiment, , And the frequency of the clock pulse a is set to 330 pps.). The driving signals output from the ports p1 to p4 of the microcomputer 8 by the microcomputer 8 are counted based on the input clock pulse a and output based on the clock pulse a. That is, as shown in FIGS. 8A and 8B, the microcomputer 8 sequentially outputs the ON signals from the ports p1 to p4 at the cycle of the clock pulse a × 2. The time during which the ON signal is output is set as the time until the clock pulse a × 3 is counted. In the present embodiment, the time until counting the clock pulse a × 3 is 3 ms × 3 = 9 ms.
[0046]
When the microcomputer 8 outputs an ON signal in the order of the ports p1, 2, 3, and 4, as shown in FIG. 8A, the stepping motor 23 is driven to rotate in the normal rotation direction. When the on signals are output in the order of the ports p4, 3, 2, and 1, the stepping motor 23 is driven to rotate in the reverse direction.
[0047]
When the stepping motor 23 is rotated in the reverse direction, that is, when the direction in which the stepping motor 23 is rotated from the normal direction to the reverse direction or from the reverse direction to the normal direction is changed, a predetermined time T1 (until clock pulse a × 5 is counted) ), An off signal is output to the stepping motor 23. Accordingly, when the rotation direction of the stepping motor 23 is changed to the opposite direction, the stepping motor 23 is prevented from slipping, and the stepping motor 23 can be accurately controlled.
[0048]
Further, when the rotation driving of the stepping motor 23 is started or when the rotation direction of the stepping motor 23 is changed to the opposite direction, the clock pulse output circuit 42 outputs a lower voltage than the normal time during the predetermined time T2 as shown in FIG. A clock pulse a ′ having a frequency may be output. In the present embodiment, the predetermined time T2 is set as a time until the clock pulse a ′ × 7 is counted. As a result, the rotation speed of the stepping motor 23 becomes slower than in the case described above, and a large torque is obtained. Further, the rotation speed of the stepping motor 23 may be arbitrarily set by making the frequency of the clock pulse a ′ arbitrarily changeable. Further, the predetermined time T2 for the slow start may be arbitrarily set.
[0049]
Further, the microcomputer 8 counts the number of clock pulses of the clock pulse a output while the stepping motor 23 is driven to rotate from the time when the micro switch 26 is turned on. According to this counting method, when the stepping motor 23 is driven to rotate in the normal rotation direction, the number of clock pulses a counted during the rotation is added. When the stepping motor 23 is driven to rotate in the reverse direction, the number of clock pulses a counted during the rotation drive in the reverse direction is subtracted. The microcomputer 8 detects the motor position of the stepping motor 23 by referring to the counted value Y. That is, it is possible to detect whether the motor position is located at the zero point or how far the motor position is from the zero point.
[0050]
Further, the microcomputer 8 sets the operation range of the stepping motor 23, and the stepping motor 23 operates between the zero point and the MAX point. In the method of setting the zero point by the microcomputer 8, as shown in the flowchart of FIG. 9, first, in step S1, the stepping motor 23 is driven to rotate in the reverse direction, and in step S2, the timer is started. Next, in step S3, the timer determines whether or not the time has expired. If it is determined that the time has not expired (NO), in step S4, it is determined whether or not the micro switch 26 has been turned on. to decide. If it is determined in step S3 that the timer has expired (YES), an error is displayed in step S7.
[0051]
If it is determined in step S4 that the stepping motor 23 has been turned on (YES), the stepping motor 23 is turned off in step S5. At this time, the arm 22 rotated counterclockwise is in a state where the micro switch 26 is turned on, as shown in FIG. 2, and the pressing portion 21b is located at the open position (upper end in the vertical direction). In step S6, the microcomputer 8 sets the current motor position of the stepping motor 23 as a zero point (origin). On the other hand, if it is determined in step S4 that the micro switch 26 has not been turned on, the process returns to step S3.
[0052]
The microcomputer 8 sets the MAX point by rotating the stepping motor 23 in the forward direction from the state where the stepping motor 23 is located at the zero point, and setting a predetermined number (positive first predetermined number) of clock pulses. The motor position of the stepping motor 23 when the stepping motor 23 is rotationally driven until a is output is set as the MAX point. In the present embodiment, the predetermined number is set to 210 (HEX). At this time, the counted value is 210 (HEX). The arm portion 22 rotates clockwise in FIG. 2, the thick portion 24 b of the elastic cap 24 is pushed down to the position shown by the dashed line in FIG. 2, and the pressing portion 21 b is moved to the closed position (vertical direction). Bottom).
[0053]
The microcomputer 8 turns off the stepping motor 23 when the count value Y becomes 0 (HEX) corresponding to the zero point or 210 (HEX) corresponding to the MAX point. Accordingly, the stepping motor 23 operates between the zero point and the MAX point, and the pressing portion 21 is positioned between the upper end and the lower end in the vertical direction.
[0054]
Next, the operation of the pressure cooker 1 by the microcomputer 8 will be described.
[0055]
First, the user stores the desired number of cups of rice and the amount of water required to cook the rice in the inner pot 2, sets the inner pot 2 on the main body 3, and then sets the desired rice after cooking. The rice cooker 31 is pressed by operating the switches 31 to 35 of the display panel 30 to set the hardness of the rice, the cooking time, and the like.
[0056]
Then, the microcomputer 8 starts the rice cooking flow as shown in the flowchart of FIG. In step S10, energization of the induction heating coil 6 is started, and the temperature of the inner pan 2 is adjusted to about 50 ° C. and preheating is applied (preheating step).
[0057]
Then, after a lapse of a predetermined time, in step S11, the microcomputer 8 energizes the induction heating coil 6 with 100% (full power) power, and executes the middle wrapper process (rice cooking process). Also, in step S12, when the temperature in the inner pan 2 is determined to be 100 ° C. by the inner pan temperature sensor 7, the power control step (rice cooking step) is executed by controlling the amount of electricity to the induction heating coil 6. In step S13, electricity is again supplied to the induction heating coil 6 at a power of 60 to 70%, the temperature in the inner pot 2 is raised to 100 ° C. or more, and a cooking process (rice cooking process) is executed.
[0058]
When the microcomputer 8 detects the dry-up by a known method, in step S14, the microcomputer 8 starts energizing the lid heater 10 disposed on the lid 4, and performs steaming and dew-sparging (smoothing step) for a predetermined time. Then, in step S15, the microcomputer 8 shifts to a heat retaining process, similarly to the known pressure cooker (heat retaining step).
[0059]
The microcomputer 8 performs a motor home return operation at the start of the preheating step. At this time, the microcomputer 8 drives the stepping motor 23 to rotate in the reverse direction, and positions the stepping motor 23 at the zero point. The microcomputer 8 turns off the stepping motor 23 when the motor origin return operation is completed.
[0060]
The microcomputer 8 performs the pressure regulation control as shown in the flowcharts of FIGS. 11 and 12 during the middle wrapper step, the power control step, the cooking step, and the spotting step. First, the microcomputer 8 sets a pressure upper limit A and a pressure lower limit B in step S20. The pressure upper limit A and the pressure lower limit B are set based on a data table 51 stored in the microcomputer 8 shown in FIG. The data table 51 includes a pressure upper limit value A and a pressure lower limit value set for each of the steps of medium dad, power control, cooking and steaming in each of the normal, firm, soft, rapid, and brown rice cooking menus. It has a value B (AD value). The microcomputer 8 sets the pressure upper limit value A and the pressure lower limit value B to 42 and 3E (HEX) based on the data table 51, for example, when the middle rice wrapping process is performed in the ordinary rice cooking menu.
[0061]
Next, in step S21, the microcomputer 8 takes in the AD value C corresponding to the voltage value output by the pressure sensor 13 based on the data table 50 shown in FIG. This AD value C represents the current pressure value in the inner pot 2. Then, in step S22, it is determined whether or not the current value C of the pressure sensor 13 is equal to or less than the lower pressure limit B. If the current value C is equal to or less than the pressure lower limit value B, it is determined in step S23 whether or not the motor position of the stepping motor 23 is located at the MAX point (position detection). At this time, the microcomputer 8 makes the determination by referring to the count value Y added or subtracted according to the rotation direction of the stepping motor 23 as described above. That is, it is determined whether or not the count value Y is 210 (HEX). If it is not the MAX point, the stepping motor 23 is driven to rotate in the normal rotation direction in step S24, and if it is the MAX point, the stepping motor 23 is turned off in step S26.
[0062]
Then, in step S25, similarly to the conventional pressure cooker, when the termination condition in each step is satisfied, the pressure regulation control is terminated and the process proceeds to the next step. Here, if the pressure adjustment control is not ended, the process returns to step S21.
[0063]
As described above, when the stepping motor 23 is driven to rotate in the normal rotation direction, the arm portion 22 rotates, and the pressing portion 21b of the closing valve pressing portion 21 is pushed down in the closing direction. The pressing portion 21b presses the closing valve 20b downward via a spring 21g having a predetermined elasticity attached to the lower surface. At this time, a pressing force is applied to the closing valve 20b by the contracted spring 21g to close the exhaust port 20c. As a result, the inside of the inner pot 2 is closed and pressurized until the pressure becomes equal to or higher than the pressure lower limit value B.
[0064]
On the other hand, if the current value C of the pressure sensor 13 is equal to or greater than the lower pressure limit B in step S22 (NO), it is determined in step S27 whether the current value C of the pressure sensor 13 is equal to or greater than the upper pressure limit A. Judge. If the current value C of the pressure sensor 13 is not equal to or higher than the upper pressure limit A (NO), in step S28, the stepping motor 23 is turned off, and the process proceeds to step S25. Thereby, the closing valve 20b is maintained in a state where the pressing force is applied by the spring 21g. As a result, the pressure in the inner pot 2 is maintained at the pressure lower limit B or more and the pressure upper limit A or less.
[0065]
If the current value C of the pressure sensor 13 is equal to or greater than the upper pressure limit A in step S27 (YES), it is determined in step S29 shown in FIG. 12 whether or not the micro switch 26 has been turned on. If not, the process proceeds to step S30. In step S30, it is determined whether or not the motor position of the stepping motor 23 is located at the zero point (position detection). At this time, the microcomputer 8 makes the determination by referring to the count value Y added or subtracted according to the rotation direction of the stepping motor 23 as described above. That is, it is determined whether or not the count value Y is 0 (HEX). If it is not the zero point, in step S31, the stepping motor 23 is driven to rotate in the reverse direction, and the process proceeds to step S25 (shown in FIG. 11).
[0066]
That is, when the stepping motor 23 is driven to rotate in the reverse direction, the arm portion 22 rotates counterclockwise, and the pressing portion 21b of the closing valve pressing portion 21 is pressed upward by the spring 21g and moves in the opening direction. I do. At this time, since the pressing force applied by the spring 21g is reduced, the closing valve 20b is pressed upward by the steam in the inner pot 2 in a high pressure state. As a result, the exhaust port 20c is opened, and the pressure in the inner pan 2 is reduced (released) until the pressure in the inner pan 2 becomes equal to or less than the pressure upper limit value A.
[0067]
If the motor position is at the zero point in step S30, the stepping motor 23 is turned off in step S33, and the process proceeds to step S25. If the micro switch 26 is turned on in step S29, the current position of the stepping motor 23 is reset to zero in step S32. At this time, the count value Y is reset to 0 (HEX). Then, in step S33, the stepping motor 23 is turned off, and the process proceeds to step S25. Thus, even when the zero point is shifted due to the slippage occurring in the stepping motor 23, accurate control can be performed by newly setting the zero point.
[0068]
As described above, the microcomputer 8 controls the pressure regulating device 15 to regulate the pressure in the inner pan 2 appropriately to the pressure lower limit B or more and the pressure upper limit A or less. Thus, by applying pressure at the time of cooking rice, it is possible to cook delicious rice with increased stickiness and sweetness.
[0069]
When the microcomputer 8 shifts to the warming step, it notifies the end of rice cooking and returns the stepping motor 23 to the zero point as shown in the flowchart of FIG. First, in step S50, the stepping motor 23 is driven to rotate in the reverse direction, and in step S51, a timer is started. Next, in step S52, the timer determines whether or not the time has expired. If it is determined that the time has not expired (NO), in step S53, it is determined whether or not the micro switch 26 has been turned on. to decide. If it is determined in step S52 that the timer has expired (YES), an error is displayed in step S55.
[0070]
If it is determined in step S53 that the stepping motor has been turned on (in the case of YES), the stepping motor 23 is turned off in step S54. At this time, the arm 22 rotated counterclockwise is located in a state where the micro switch 26 is turned on, as shown in FIG. On the other hand, if it is determined in step S53 that the micro switch 26 has not been turned on, the process returns to step S52. Thereby, when attaching the inner lid 11, the attaching operation can be performed smoothly without the arm portion 22 pressing the pressing portion 21b. Also, when the mode shifts to the cancel mode, it is preferable that the stepping motor 23 is similarly returned to the zero point.
[0071]
Further, as shown in the data table 51, the cooking method can be changed by changing the set upper pressure limit and lower pressure limit according to each rice cooking menu. Alternatively, the rice cooking time may be shortened by changing the pressure upper limit value A to a larger value and cooking the rice with a higher pressure.
[0072]
As a modified example of the above embodiment, a pressure adjusting device 15 'as shown in FIGS. 15A and 15B may be provided. This pressure adjusting device 15 'has an arm portion 22' provided with a fulcrum portion 22g at the center. The arm portion 22 'is attached rotatably about a fixed shaft 22i. In addition, one end 22j of the arm portion 22 ′ located on the left side in FIG. 15 is abutted or attached to the upper surface of the pressing portion 21b.
[0073]
When the stepping motor 23 is driven to rotate in the normal direction or the reverse direction as shown by the arrow P in FIG. 15, the arm portion 22 ′ rotates in the counterclockwise direction or the clockwise direction shown by the arrow Q. It is designed to be driven. Thus, the pressing portion 21b moves in the closing direction or the opening direction along the vertical direction indicated by the arrow R in FIG.
[0074]
Further, a micro switch 26 is provided so as to be located below the vicinity of the center of the arm portion 22 'with the arm portion 22' attached to the motor stay 25.
[0075]
Further, as another modified example of the embodiment, as shown in FIG. 16A, instead of providing the pictograph display section 30g of the display panel 30, a numerical display section 30a for displaying the time on the display panel 30 is provided. The pressure in the inner pot 2 may be displayed in a stepwise manner by using a block. FIG. 16A shows that the numerical value display section 30a is in the high pressure state by three steps from the normal pressure state. Further, as shown in FIG. 16 (b), the pressure in the inner pot 2 may be numerically displayed by the numerical display section 30a during the pressure regulation control.
[0076]
Further, as another modified example of the embodiment, when the stepping motor 23 is rotationally driven during the pressure regulation control, a speed changing process may be performed as shown in a flowchart of FIG. The speed changing process is performed when the pressure in the inner pan 2 is increased or decreased in the pressure regulation control, that is, when the stepping motor 23 is driven to rotate in the normal direction or the reverse direction.
[0077]
In this speed variable process, in step S41, the pressure difference between the pressure value C detected by the pressure sensor 13 and the pressure upper limit value A or the pressure lower limit value B is 0.3 atm (predetermined pressure difference) or more. Determine whether or not. If the pressure difference is equal to or higher than 0.3 atm, in step S42, the frequency of the clock pulse a is set to 500 pps, which is higher than the normal frequency of 330 pps. On the other hand, if the pressure difference is less than 0.3 atm in step S41 (NO), the frequency of the clock pulse a is set to 100 pps, which is lower than the normal frequency of 330 pps, in step S43. As described above, when the clock pulse a is set to the frequency of 500 pps, the rotation speed of the stepping motor 23 becomes faster than that in the normal state, and when the clock pulse a is set to the frequency of 100 pps, the rotation speed of the stepping motor 23 becomes It is slower than normal.
[0078]
When the pressure difference between the pressure upper limit value A and the pressure lower limit value B is large (0.3 atm or more), the rotation speed of the stepping motor 23 is set to be higher than usual, so that the closing valve is pressed. The moving speed of the pressing portion 21b of the portion 21 also increases. As a result, the pressure is rapidly reduced or increased until the detected pressure C in the inner pot 2 reaches the pressure upper limit value A or the pressure lower limit value B. When the pressure difference between the pressure upper limit value A and the pressure lower limit value B is small (less than 0.3 atm), the rotation speed of the stepping motor 23 is set lower than usual, so The moving speed of the pressing portion 21b of the valve pressing portion 21 also decreases. As a result, when the pressure in the inner pan 2 is close to the upper pressure limit A or the lower pressure limit B, fine pressure adjustment is possible.
[0079]
Next, other embodiments will be described, but portions similar to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0080]
(2nd Embodiment)
The stepping motor 23 of the pressure cooker 1 according to the second embodiment of the present invention is different from the operation range (the count value Y is 0 (HEX) to 210 (HEX)) of the first embodiment, and is -315 (HEX). ) (Second negative predetermined number) to 210 (HEX) (first positive predetermined number). That is, the stepping motor 23 is set to operate also in the negative region.
[0081]
FIGS. 18 and 19 show flowcharts of the pressure regulation control at this time. Unlike the pressure regulation control of the first embodiment shown in FIGS. 11 and 12, in step S27-1, it is determined whether or not the motor position of the stepping motor 23 has exceeded a negative allowable value (-315 (HEX)). Judge (position detection). At this time, the microcomputer 8 makes the determination by referring to the count value Y indicating the motor position of the stepping motor 23. That is, it is determined whether or not the count value Y is equal to or less than -315 (HEX). If the count value Y does not exceed the negative allowable value in step S27-1 (NO), the process proceeds to step S29. On the other hand, when the count value Y exceeds the negative allowable value (in the case of YES), the process proceeds to step S27-2, and the stepping motor 23 is turned off.
[0082]
Further, unlike the pressure regulation control of the first embodiment, the step S30 in the first embodiment is not provided. That is, even if the motor position of the stepping motor 23 is at the zero point, the stepping motor 23 is rotated in the reverse direction in step S31 without turning off the stepping motor 23.
[0083]
For example, noise enters the microswitch 26 when the motor position of the stepping motor 23 is in the positive region, and the microswitch 26 is erroneously detected as being turned on, or slips during the rotation operation of the stepping motor 23 during pressure regulation control. Occurs, the zero point is set within the operating range of the positive region 0 (HEX) to 210 (HEX) of the stepping motor 23. At this time, even if the motor position of the stepping motor 23 reaches the zero point by the pressure regulation control, the stepping motor 23 can be continuously driven to rotate to the negative region. As a result, it is possible to return to the correct zero point of the stepping motor 23. The negative operating range is set to have an area 1.5 times the positive operating range so that the stepping motor 23 can return to the correct zero point even when the zero point is erroneously set near the MAX point. Is set.
[0084]
(Third embodiment)
FIGS. 20 and 21 show a flowchart of pressure regulation control of the pressure cooker 1 according to the third embodiment of the present invention. Unlike the pressure regulation control of the first embodiment shown in FIGS. 11 and 12, when the pressure value in the inner pot 2 detected by the pressure sensor 13 is 1.0 to 1.09 atm in step S31-1. Then, the process proceeds to step S31-2, in which the stepping motor 23 is rotationally driven (turned on) in the reverse direction for 500 ms, and in step S31-3, the stepping motor 23 is turned off for 1 second.
[0085]
In step S31-1, when the pressure value in the inner pan 2 is 1.1 to 1.19 atm, the process proceeds to step S31-4, and the stepping motor 23 is rotationally driven in the reverse direction for 100 ms (ON). Then, in step S31-5, the stepping motor 23 is turned off for 3 seconds.
[0086]
In step S31-1, when the pressure value in the inner pan 2 is 1.2 to 1.3 atm, the process proceeds to step S31-6, and the stepping motor 23 is rotationally driven in the reverse direction for 20 ms (ON). Then, in step S31-7, the stepping motor 23 is turned off for 5 seconds.
[0087]
Thus, in the pressure cooker 1 according to the third embodiment, after the stepping motor 23 is rotationally driven (turned on) in the reverse direction for 500 ms, 100 ms or 20 ms (predetermined on-time), 1s, 3s or 5s. During the (predetermined off time), the stepping motor 23 is turned off. Thus, the stepping motor 23 is repeatedly turned on / off, and the pressure in the inner pot 2 is reduced stepwise.
[0088]
Further, the time for driving the stepping motor 23 to rotate is changed according to the pressure in the inner pan 2. When the pressure in the inner pan 2 is high (1.2 to 1.3 atm), the stepping motor 23 is driven to rotate in the reverse direction for a short time of 20 ms, so that the stepping motor 23 is discharged to the steam discharge path 18 via the exhaust port 20c. And the amount of steam discharged to the outside of the lid 4 can be reduced. Thus, the danger of the user being burned by the steam discharged from the steam port 4c of the lid 4 can be avoided, and the safety is improved.
[0089]
When the pressure in the inner pan 2 is low (1.0 to 1.09 atm), the stepping motor 23 is driven to rotate in the reverse direction for 500 ms, and the time for turning off the stepping motor 23 is only 1 s. Therefore, the pressure in the inner pan 2 can be quickly reduced. By reducing the pressure in such a short time, excess moisture adhering to the surface of the rice can be blown off, particularly in the rice drying step, and it becomes possible to cook deliciously. In the spotting process, the pressure regulation control may be ended when the detected pressure value in the inner pot 2 reaches 1.0 atm.
[0090]
Further, the on-time during which the stepping motor 23 is driven to rotate in the reverse direction and the time during which the stepping motor 23 is turned off may be individually set according to each rice cooking menu, each process, or rice cooking capacity.
[0091]
(Fourth embodiment)
FIG. 22 shows a pressure cooker 1 according to a fourth embodiment of the present invention. The pressure cooker 1 includes a fan 60 and a hybrid power supply IC (HIC) 61, and other structures are the same as those of the above-described embodiment.
[0092]
The fan 60 is disposed between the body 3a and the protection frame 5, and forcibly sucks outside air from an intake port (not shown) during a rice cooking operation, and the microcomputer 8 disposed at an opposite position. Is directly exposed to outside air to cool the elements of the microcomputer 8 and the like.
[0093]
The hybrid power supply IC 61 generates a DC output from a 100 V AC power supply 61a and supplies the current to the fan 60, the stepping motor 23, the microcomputer 8, and the like. The current capacity of the hybrid power supply IC 61 is 200 mA, and cannot supply a current of 200 mA or more. The current required for driving the fan 60 is 130 mA, and the driving current required for the stepping motor 23 is 60 mA. The drive current required by the microcomputer 8 and other members is 40 mA.
[0094]
Next, the rice cooking operation of the pressure rice cooker 1 by the microcomputer 8 will be described.
[0095]
As shown in the flowchart of FIG. 23, the microcomputer 8 supplies a current of 130 mA to the fan 60 and drives (turns on) the fan 60 in step S70. In step S71, energization of the induction heating coil 6 is started, and the temperature of the inner pot 2 is adjusted to about 50 ° C. and preheating is applied (preheating step). At this time, the total value of the required current is 170 mA used by the fan 60, the microcomputer 8, and other members.
[0096]
When the predetermined time has elapsed, in step S72, the microcomputer 8 energizes the induction heating coil 6 with 100% (full power) electric power to execute the middle papper process. When it is determined that the temperature in the inner pan 2 has reached 100 ° C. by 7, the power control step is executed by controlling the amount of electricity to the induction heating coil 6 (pressure regulation mode). The microcomputer 8 performs the same pressure control as in the above-described embodiment at the time of the middle wrapper process and the power control process in the pressure control mode.
[0097]
Then, in step S73, it is determined whether or not the pressure adjustment mode has been completed. When the pressure adjustment mode is being executed (NO in step S73), in step S77, the stepping motor 23 is turned on. It is determined whether or not there is. If the stepping motor is on, the fan 60 is turned off in step S78, and the process returns to step S73. On the other hand, if the stepping motor 23 is not turned on, the fan 60 is driven (turned on) in step S79. Then, the process returns to step S73.
[0098]
At this time, the total value of the required current is 100 mA used by the stepping motor 23, the microcomputer 8 and other members when the stepping motor 23 is driven. When the stepping motor 23 is not driven, the current is 170 mA used by the fan 60, the microcomputer 8, and other members. Therefore, the current capacity of the hybrid power supply IC 61 does not exceed 200 mA. Therefore, since a power supply IC having a current capacity of 200 mA or more is not required, an increase in cost and an increase in size can be avoided.
[0099]
When the pressure regulation mode ends (YES in step S73), in step S74, the induction heating coil 6 is again energized with 100% (full power) power, and the temperature in the inner pan 2 is reduced to 100%. ℃ to perform the cooking process. At this time, the fan 60 is being driven.
[0100]
When the microcomputer 8 detects the dry-up by a known method, in step S75, the microcomputer 8 starts energization of the lid heater 10 disposed on the lid 4, and performs steaming and dew-exposure (smoothing process) for a predetermined time. At this time, the fan 60 is being driven. Then, in step S76, the microcomputer 8 shifts to a heat retaining process, similarly to the well-known pressure cooker (heat retaining step).
[0101]
【The invention's effect】
As is clear from the above description, in the rice cooker of the present invention, the inner pot, the main body that houses the inner pot, the lid that is attached to the main body so as to be openable and closable, and the inner pot are heated. Heating means, an exhaust port provided in the lid for discharging steam in the inner pan, a pressure detecting means for detecting pressure in the inner pan, a closing valve closing the exhaust port, a closing valve A pressing portion that applies a pressing force and is movably provided between a closed position and an open position, a pressing portion moving unit that moves the pressing portion in a closing direction toward the closing position or an opening direction toward the opening position, And a pressure regulating device having a forward / reverse rotating stepping motor for driving the pressing portion moving means, and rotating the stepping motor of the pressure regulating device in the forward direction or the reverse direction based on a signal from the pressure detecting means at the time of pressure cooking. Drive and push By moving the portion in the closing direction or the opening direction, a control means for increasing or decreasing the pressure in the inner pot is provided, so that it is possible to cook rice by applying high pressure during cooking, and it is possible to apply the pressure to be applied. Pressure rice cooker which can obtain delicious rice with increased stickiness and sweetness by changing the pressure to the above pressure can be provided. In addition, by cooking rice under high pressure, the rice cooking time can be shortened.
[0102]
In particular, the control means sets a pressure upper limit value and a pressure lower limit value, and when the pressure value detected by the pressure detection means is equal to or less than the pressure lower limit value, drives the stepping motor to rotate in the normal rotation direction, and When the pressure is equal to or higher than the upper limit, the stepping motor is driven to rotate in the reverse direction, and when the pressure value is equal to or higher than the lower pressure limit and equal to or lower than the upper pressure limit, the stepping motor is turned off. The pressure is appropriately adjusted to be equal to or higher than the lower pressure limit and equal to or lower than the upper pressure limit.
[0103]
In particular, when the pressure difference between the pressure value detected by the pressure detection means and the pressure upper limit value or the pressure lower limit value is equal to or greater than a predetermined pressure difference, the control means increases the rotation speed of the stepping motor and sets the pressure difference to a predetermined pressure. When the difference is less than the difference, the rotation speed of the stepping motor is reduced, so that when the pressure difference is large, the pressure in the inner pan can be quickly reduced or increased. When the pressure difference is small, fine pressure adjustment is possible.
[0104]
When the pressure in the inner pan is reduced, the control means drives the stepping motor to rotate in the reverse direction for a predetermined on-time, and then turns off the stepping motor for a predetermined off-time. Can be gradually reduced.
[0105]
Further, by setting the ON time and the OFF time in accordance with the pressure in the inner pot, it is possible to reduce the amount of steam to be discharged and to quickly reduce the pressure in the inner pot.
[Brief description of the drawings]
FIG. 1 is a schematic view of a pressure cooker according to a first embodiment of the present invention.
FIG. 2A is an enlarged view of the pressure regulator of FIG. 1; (B) is a top view of (a).
FIG. 3 is an exploded perspective view of the pressure adjusting device of FIG.
FIG. 4 is a perspective view of the lid of FIG. 1;
FIG. 5 is a front view of the operation panel of FIG. 1;
FIG. 6 is a drive circuit diagram of a stepping motor of the pressure cooker of FIG. 1;
FIG. 7 is a data table stored in the microcomputer of FIG. 1;
FIGS. 8A and 8B are waveform diagrams of driving signals output from a microcomputer for driving a stepping motor.
FIG. 9 is a flowchart showing zero point setting control of the pressure cooker.
FIG. 10 is a flowchart showing rice cooking control of the pressure rice cooker.
FIG. 11 is a flowchart showing pressure regulation control of the pressure cooker according to the first embodiment of the present invention.
FIG. 12 is a flowchart showing pressure regulation control of the pressure cooker according to the first embodiment of the present invention.
FIG. 13 is a data table used during pressure regulation control.
FIG. 14 is a flowchart showing a zero-point return process of the pressure cooker.
FIG. 15A is a side view showing a modified example of the pressure regulator of FIG. 1; (B) is a top view of (a).
FIGS. 16A and 16B are front views showing a modification of the operation panel in FIG.
FIG. 17 is a flowchart showing speed change processing of the pressure cooker according to the present invention.
FIG. 18 is a flowchart showing pressure regulation control of the pressure cooker according to the second embodiment of the present invention.
FIG. 19 is a flowchart showing pressure regulation control of the pressure cooker according to the second embodiment of the present invention.
FIG. 20 is a flowchart showing pressure regulation control of the pressure cooker according to the third embodiment of the present invention.
FIG. 21 is a flowchart showing pressure regulation control of the pressure cooker according to the third embodiment of the present invention.
FIG. 22 is a schematic diagram of a pressure cooker according to a fourth embodiment of the present invention.
FIG. 23 is a flowchart showing rice cooking control of the pressure rice cooker of FIG. 22.
[Explanation of symbols]
1. Pressure cooker
2. Inner pot
3 ... body
4: Lid
6. Induction heating coil (heating means)
8. Microcomputer (control means)
13. Pressure sensor (pressure detecting means)
15 ... Pressure adjusting device
20b ... shut-off valve
20c ... Exhaust port
21b ... Pressing part
21g… Spring
22 ... arm part (pressing part moving means)
22g ... fulcrum
23 ... Stepping motor
26 ... Micro switch
42 ... Clock pulse output circuit

Claims (14)

  1. Inner pot,
    A main body containing the inner pot;
    A lid that is attached to the main body so as to be openable and closable, and seals the inner pot;
    Heating means for heating the inner pot,
    An exhaust port for discharging steam in the inner pan provided on the lid,
    Pressure detection means for detecting the pressure in the inner pot,
    A closing valve for closing the exhaust port, a pressing portion for applying a pressing force to the closing valve via a spring having a predetermined elastic force, and a pressing portion movably provided between a closing position and an opening position; A pressing unit moving means for moving in the closing direction toward the closing position or the opening direction toward the opening position, and a pressure regulating device having a forward / reverse rotatable stepping motor for driving the pressing unit moving means,
    At the time of pressure cooked rice, based on a signal from the pressure detecting means, by rotating the stepping motor of the pressure regulating device in the normal direction or the reverse direction to move the pressing portion in the closing direction or the opening direction, A pressure cooker comprising control means for increasing or decreasing the pressure in the inner pot.
  2. The control means includes:
    Set the upper pressure limit and lower pressure limit,
    When the pressure value detected by the pressure detecting means is equal to or less than the lower pressure limit, the stepping motor is driven to rotate in the normal rotation direction,
    When the pressure value is equal to or higher than the upper pressure limit, the stepping motor is driven to rotate in a reverse direction,
    The pressure rice cooker according to claim 1, wherein the stepping motor is turned off when the pressure value is equal to or higher than the lower pressure limit and equal to or lower than the upper pressure limit.
  3. The pressure cooker according to claim 2, wherein the upper pressure limit and the lower pressure limit can be arbitrarily set.
  4. The control means increases the rotation speed of the stepping motor when the pressure difference between the pressure value detected by the pressure detection means and the pressure upper limit value or the pressure lower limit value is equal to or greater than a predetermined pressure difference. The pressure cooker according to claim 2 or 3, wherein when the difference is less than the predetermined pressure difference, the rotation speed of the stepping motor is reduced.
  5. When the pressure in the inner pan is reduced, the control unit drives the stepping motor to rotate in the reverse direction for a predetermined ON time, and then turns off the stepping motor for a predetermined OFF time. The pressure cooker according to any one of claims 1 to 4, characterized in that:
  6. The pressure rice cooker according to claim 5, wherein the on-time and the off-time are set according to a pressure in the inner pot.
  7. 7. The pressure cooker according to claim 5, wherein the ON time and the OFF time are individually set according to each rice cooking menu, each process, or the rice cooking capacity.
  8. A clock pulse output circuit that outputs a clock pulse having a predetermined frequency to the control unit; and a control unit that is turned on when the pressing unit moving unit contacts the pressing unit when the pressing unit is moved to the open position. A micro switch that outputs a signal to
    The control means counts the number of clock pulses output while the stepping motor is rotationally driven in a forward direction or a reverse direction from a time point when the microswitch is turned on. The method according to claim 1, wherein when the stepping motor is driven to rotate in the reverse direction, the counted number of clock pulses is subtracted when the stepping motor is driven to rotate in the reverse direction. 8. The pressure cooker according to any one of 7 above.
  9. When the micro switch is turned on, the control means sets the motor position of the stepping motor to a zero point, rotates the stepping motor in a normal rotation direction, and counts the counted value to a positive first predetermined number. 9. The pressure rice cooker according to claim 8, wherein the motor position of the stepping motor when the condition is reached is set as a MAX point.
  10. 10. The stepping motor according to claim 9, wherein the control unit turns off the stepping motor when the count value becomes 0 corresponding to the zero point or the positive first predetermined number corresponding to the MAX point. 2. A pressure cooker according to claim 1.
  11. 10. The method according to claim 9, wherein the control unit turns off the stepping motor when the count value reaches the first positive predetermined number or the second negative predetermined number corresponding to the MAX point. The described pressure cooker.
  12. 12. The device according to claim 1, wherein the pressing portion moving means is an arm portion rotatably provided in conjunction with an output shaft of the stepping motor and arranged above the pressing portion. The described pressure cooker.
  13. The pressure cooker according to any one of claims 1 to 12, wherein the control unit turns off the stepping motor for a predetermined time when changing the rotation direction of the stepping motor to the opposite direction.
  14. 14. The method according to claim 1, wherein the control unit reduces the initial rotation speed of the stepping motor when the rotation of the stepping motor is started or when the rotation direction of the stepping motor is changed in the opposite direction. A pressure cooker according to the present invention.
JP2002221231A 2002-07-30 2002-07-30 Pressure cooker Active JP3935019B2 (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006326037A (en) * 2005-05-27 2006-12-07 Zojirushi Corp Pressure rice cooker
JP2009082755A (en) * 2009-01-30 2009-04-23 Zojirushi Corp Pressure rice cooker
JP2010214114A (en) * 2009-03-14 2010-09-30 Wmf Wuerttembergische Metallwarenfabrik Ag Steam cooking method and steam pressure cooking device, desirably pressure cooker
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JP2010214114A (en) * 2009-03-14 2010-09-30 Wmf Wuerttembergische Metallwarenfabrik Ag Steam cooking method and steam pressure cooking device, desirably pressure cooker
US9498039B2 (en) 2014-04-11 2016-11-22 Panasonic Intellectual Property Management Co., Ltd. Heating blower
CN106551620A (en) * 2015-09-25 2017-04-05 佛山市顺德区美的电热电器制造有限公司 Cooker and its control method
CN106551618A (en) * 2015-09-25 2017-04-05 佛山市顺德区美的电热电器制造有限公司 Cover assembly and cooking apparatus
CN106551617A (en) * 2015-09-25 2017-04-05 佛山市顺德区美的电热电器制造有限公司 The cooking control method of electric cooker and electric cooker
JP2018515269A (en) * 2015-09-25 2018-06-14 佛山市▲順▼▲徳▼区美的▲電▼▲熱▼▲電▼器制造有限公司Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co.,Limited Rice cooker and cooking control method of rice cooker
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WO2021051680A1 (en) * 2019-09-19 2021-03-25 珠海格力电器股份有限公司 Steam valve assembly and cooking device having same
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