JP2005296423A - rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve easiness-to-use by automatically correcting a difference of an output value of a no-load state of a weight detecting means, in a rice cooker having the function of detecting weight of preparations put in a pot. <P>SOLUTION: The pot 12 is detachably stored in a rice cooker body 10 having an opening upper surface. An upper surface opening part of the rice cooker body 10 is openably-closably covered with a lid 20. The pot 12 is heated by a heating means 201, and the temperature of the preparations is detected by a temperature detecting means 15. Weight of the pot 12 is stored in a pan weight storage means 205 for storing the weight. A lid opening-closing detecting means 21 for detecting opening-closing of the lid 20 detects lid opening. When a pan detecting means 16 for detecting the existence of the pot 12 detects the nonexistence the pot 12, the output value of a weight detecting means 40 for detecting the total weight of the pot 12 and weight of the preparations put in the pot 12, is set to a value (a zero value) in a no-load, and is stored in a zero value storage means 206. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rice cooker having a function of detecting the weight of a food item put in a pan.

  Conventionally, this type of rice cooker has an operation panel, a buzzer, and a weight measuring means for measuring weight, and can accurately measure the amount of rice and the amount of water corresponding to a desired amount of rice set by the user (set amount of rice set). It is what I did. On the operation panel, a cup number setting key, weight key, clear key, and number display section are arranged. The user prepares cooking rice by the following procedure.

  The user turns on the cup number setting key, and turns off the cup number setting key when the desired amount of rice cooking (number of cups) is displayed on the number display section. Store the empty pot in the predetermined position of the rice cooker and turn on the weight key. The weighing mode starts, and the weight (g) of the pan is displayed on the numeric display. Next, the clear key is turned on, and the display of the numeric display unit is reset to 0 g. In this state, put rice in the pan. The amount of rice is adjusted so that the amount of rice (weight) matches the weight of rice corresponding to the set amount of cooked rice and the buzzer for proper notification sounds.

Next, when the clear key is turned on again, the display of the numeric display unit is reset to 0 g and the water weight measurement state is set. When water is supplied to the pan, the weight of the water is displayed on the numeric display. Adjust the water so that the weight of water matches the weight of water corresponding to the set amount of cooked rice and the buzzer for proper notification sounds. The user can accurately weigh the rice and water based on the buzzer sound (see, for example, Patent Document 1).
JP-A-61-146215

In such a conventional rice cooker, the output of the weight measuring means is output even when the pan is not loaded in the rice cooker body. When the no-load output of the weight detection means is Z, the output when the pan is set in the rice cooker body (nothing in the pan) is N, and the output per 1 g is m. The weight N1 of
N1 = (NZ) / m
It becomes. When the pan is set in the rice cooker body and the output of the weight detection means when the cook is contained in the pan is M, the weight M1 of the cook is
M1 = (M−Z) / m−N1
It becomes.

  Here, the output value Z of the weight detection means when there is no load changes depending on aging or room temperature. The change in the output value causes an error in weight detection. Therefore, by inputting the output Z when there is no load immediately before the weight measurement, it is necessary to perform a zero reset corresponding to the change in output when the load cell is not loaded, thereby eliminating the error. In the conventional rice cooker, before the weight measurement, the clear key is pressed and the state where nothing is in the pan is set to 0 g, thereby correcting the deviation.

  However, it is necessary to press the clear key before use, which is very inconvenient for the user.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to automatically correct the deviation of the output value of the weight detection means in the no-load state, thereby improving usability.

  In order to achieve the above object, the present invention detachably stores a pan in a rice cooker body having an open top surface, covers the top opening of the rice cooker body so as to be freely opened and closed, and heats the pan by heating means. At the same time, the temperature of the food is detected by the temperature detection means, stored in the pan weight storage means for storing the weight of the pan, and the lid opening / closing detection means for detecting the opening / closing of the lid detects the opening of the lid and detects the presence or absence of the pan. When the pan detection means detects that there is no pan, the output value of the weight detection means that detects the total weight of the pan and the weight of the food put in the pan is zero as the value at zero load (zero value) This is stored in the value storage means.

  As a result, when the lid is open and the pan is not set in the rice cooker body, the weight detection means is in a no-load state, so by storing the value at that time as a zero value, the ambient temperature and aging deterioration automatically The deviation of the output value in the no-load state of the weight detection means due to can be corrected, and the usability can be improved.

  The rice cooker of this invention can correct | amend the shift | offset | difference of the weight detection automatically by ambient temperature or aged deterioration, and can improve usability.

  1st invention heats the said rice cooker main body with which the upper surface opened, the pan detachably accommodated in the said rice cooker main body, the lid | cover which opens and closes the upper surface opening part of the said rice cooker main body, and opening and closing Heating means, temperature detecting means for detecting the temperature of the food, time measuring means for measuring the time, weight detecting means for detecting the total weight of the pan and the weight of the food put in the pan, The pan weight storage means for storing the weight of the pan, the lid opening / closing detection means for detecting opening / closing of the lid, the pot detection means for detecting presence / absence of the pan, and the lid opening / closing detection means detects the opening of the lid; And zero value storage means for storing the output value of the weight detection means as a no-load value (zero value) when the pan detection means detects that there is no pan, and the lid is open. When the pan is not set in the rice cooker body, the weight detection means is negative Since it is in a state, the value detected by the weight detection means 40 at that time is stored in the zero value storage means 206 as a zero value, so that even if the zero value is shifted due to temperature or aging, the zero value is stored every time it is used. Even if the clear key is not pressed, the deviation of the output value due to the ambient temperature or aging deterioration can be automatically corrected, and the usability can be improved.

  According to a second invention, in the first invention, the zero value stability detecting means for storing the zero value in the zero value storage means only when the value of the zero value is stable for a certain time and the same value is inputted. Even if the zero value is not stabilized due to vibration or the like, an accurate zero value can be input by inputting after the zero value is stabilized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a rice cooker according to Embodiment 1 of the present invention, and FIG. 2 is a partially cutaway side view of the rice cooker. In order to simplify the drawing, lead wires and the like for electrical connection are omitted. The rice cooker according to the first embodiment is a rice cooker in which the user can accurately adjust the amount of water according to the hardness of the favorite rice.

  As shown in FIG. 2, the rice cooker body 10 has an upper surface that is open and a lid 20 that covers the upper surface opening is provided to be openable and closable. The storage unit 30 of the rice cooker main body 10 includes an upper frame 32 and a lower coil base 31, and the storage unit 30 stores the magnetic pot 12 in a detachable manner. A heating coil 13 for inductively heating the pan 12 is disposed at a portion of the coil base 31 facing the bottom of the pan 12.

  As shown in FIG. 1, the circuit board 14 includes a driving unit 202, a rice cooking control unit 203, a timing unit 204, a pan weight storage unit 205, a zero value storage unit 206, and the like, and the heating coil 13 constituting the heating unit 201. The pot 12 is induction-heated by controlling the operation, and the food 19 in the pot 12 is cooked. Here, the rice cooking control means 203, the timing means 204, the pan weight storage means 205, and the zero value storage means 206 are realized by a microcomputer 100 (hereinafter referred to as a microcomputer) shown in FIG. The microcomputer 100 also includes a portion that is calculated by the weight detection means 40 according to the expression (1) described later.

  The cooked food 19 is rice before cooking rice, a mixture of rice and water, cooked rice, or the like. This rice cooker has a power cord (not shown) and is in a “power-on” state when commercial power is supplied from the power cord.

  The temperature detection means 15 is disposed at the bottom of the coil base 31 and detects the temperature of the pan 12. This temperature detection means 15 is located at the center of the bottom of the pot 12 when the pot 12 is stored in the storage portion 30. The temperature of the food item 19 is detected by detecting the temperature of the pot 12 and the output is input to the rice cooking control means 203. The pan detection means 16 detects whether or not the pan 12 is stored in the storage portion 30, and the pan detection means 16 is constituted by a micro switch rigidly connected to the rice cooker body 10, and the pan 12 is When stored in the storage unit 30, the protrusion provided on the bottom of the temperature detection unit 15 presses the micro switch, and the pan detection unit 16 outputs an ON signal.

  The lid opening / closing detection means 21 detects the opening / closing of the lid 20, and this lid opening / closing detection means 21 is provided in the rice cooker body 10 and is constituted by a microswitch. When the lid 20 is opened, the hinge portion of the lid 20 is a microswitch. And the lid open / close detection means 21 outputs an ON signal. The pan detection means 16 and the lid open / close detection means 21 are always operating when the rice cooker is turned on, and output an on signal or an off signal.

  The weight detection means 40 detects the weight of the pan 12, and this weight detection means 40 is composed of a support portion 17 and a load cell 18, and the load cell 18 is a robust load cell (load converter). The main body 10 is rigidly connected. A resistance wire strain gauge (not shown) is attached to the load cell 18. A change in resistance of the strain gauge when the load cell 18 is distorted is extracted as an electrical signal by a bridge circuit.

  The support portion 17 has a shape in which three protrusions are provided on a thin plate, and the thin plate is screwed to one end of the load cell 18. The protrusions of the support part 17 respectively penetrate three holes provided in the bottom part of the coil base 31, and when the pan 12 is not stored in the storage part 30, the load cell 18 detects the weight of the support part 17. . When the pan 12 is stored in the storage unit 30, the bottom of the pan 12 comes into contact with the tip of the protrusion of the support unit 17, and the load cell 18 is distorted. When the pan 12 is stored in the storage unit 30, the load cell 18 detects the total weight of the support unit 17, the pan 12, and the food 19 in the pan 12. That is, the weight detection means 40 is configured to accurately measure the weight of the pan 12 and the object to be heated (cooked item 19) through the support portion 17 that supports the bottom surface of the pan at three points.

  Electrical signals from the temperature detection means 15, the pan detection means 16, the lid opening / closing detection means 21 and the weight detection means 40 are input to the circuit board 14, respectively.

  FIG. 3 is a diagram showing an operation / display unit of the rice cooker of the present embodiment, although not shown in FIGS. 1 and 2. As shown in FIG. 3, an operation / display unit 50 is provided on the front surface of the rice cooker body 10. The operation / display unit 50 is provided with a key input means 51, a water amount display unit 62, and a liquid crystal display panel 53. As key input means 51, rice weighing switch 51a, heat retention switch 51b, reservation switch 51c for timer reservation, course switch 51d for selecting rice cooking course, rice cooking switch 51e, cancel / off switch 51f, reservation time (hours) Hour switch 51g and minute switch 51h are arranged for matching the minute and minute).

  The water amount display unit 52 includes five lamps 52 a to 52 e arranged on the back surface of the operation / display unit 50. The hardness of the rice depends on the amount of rice and water. After putting rice into the pan 12, the rice measuring switch 51a is pressed to measure the amount of rice, and then water is added. The rice cooker according to the first embodiment measures the amount of water that the user puts in the pan 12, and the corresponding lamp among the lamps 52a to 52e of the water amount display unit 52 according to the amount of rice and the hardness of the rice corresponding to the amount of water. Lights up or flashes. The characters “Kai” on the upper left of the lamp 52a, “Standard” on the upper side of the lamp 52c, and “Softer” on the upper right of the lamp 52e are displayed. Water can be added to cook hard rice.

  The liquid crystal display panel 53 is provided with an operation guidance display unit 54 and a rice amount display unit 55. The operation guidance display unit 54 is a display unit for displaying an operation to be performed next by the user or a current state. The operation guidance display unit 54 is provided with a “water adjustment” display unit 54 a and a “press rice cooking” display unit 54 b. The operation to be performed next by the user is indicated by displaying the background portion of the characters (characters “watering” or “cooking”) on the display units 54a and 54b in black. The rice amount display unit 55 displays the measurement result of the amount of rice (the number of cups) that the user has put in the pan 12.

  The display example of FIG. 3 is a display in a state where the measurement of rice and water has been completed. The amount of rice “2.3 cups” is displayed on the rice amount display portion 55. The background of the characters “cooking rice” in the “press rice cooking” display portion 54b is displayed in black, prompting the user to press the rice cooking switch 51e.

  FIG. 4 is a circuit diagram of the circuit board 14 of the present embodiment. As shown in FIG. 4, the heating coil 13 induction heats the pan 12. AC power is supplied from a commercial power source, rectified by a diode bridge 102, and high-frequency power for induction heating is generated by an inverter circuit including a smoothing capacitor 103, a resonance capacitor 104, a switching element 105, and a heating coil 13. The power supply IC 106 supplies power for operation to each circuit. The inverter circuit is driven by a drive IC 107 and an induction heating control IC 108 constituting the driving means 202.

  The thermistor 109 is built in the temperature detection means 15 and detects the temperature of the pan 12 by utilizing the fact that the thermistor 109 changes its resistance value depending on the temperature. By the oscillation of the crystal oscillator 110, the timer in the microcomputer 100 is counted to measure time. Then, by controlling the induction heating control IC 108 based on the temperature input to the microcomputer 100 and the time being measured, the heating of the pan 12 is controlled to perform rice cooking.

  The lid opening / closing detection switch 111 constitutes the lid opening / closing detection means 21, and detects that the lid is opened or closed by turning off the switch when the lid 20 is opened and turning on when the lid 20 is closed. The display is performed by the liquid crystal display panel 53 and the lamp 52.

  In the weight detection, since the signal from the load cell 18 is very small, it is amplified by the differential amplifier circuit 112 composed of an operational amplifier and a resistor and input to the microcomputer 100. Since the output from the load cell 18 is proportional to the weight applied to the load cell 18, the value obtained by dividing the weight input of the microcomputer 100 by the input per gram is the weight value.

The operation and action of the above configuration will be described. The output of the weight detection means 40 is output even when the pan 12 is not loaded in the rice cooker body 10. The input to the microcomputer 100 when there is no load of the weight detection means 40 is Z, and the input when the pan 12 is set in the rice cooker body 10 (the pan 12 has nothing in it) If the microcomputer input is m, the weight N1 of the pan 12 is
N1 = (NZ) / m
It becomes.

  The weight N1 of the pan 12 is stored in the pan weight storage means 205. This pan weight storage is performed at the time of shipment from the factory, and the user need not be aware of it.

When the pan 12 is set in the rice cooker main body 10 and the input to the microcomputer 100 of the weight detection means 40 when the cook is contained in the pan 12 is M, the weight M1 of the cook is
M1 = (M−Z) / m−N1 (1)
It becomes.

  Here, the output value of the input Z to the microcomputer 100 at the time of no load of the weight detection means 40 varies depending on the aging of the load cell 18 or the room temperature. The change in the output value causes an error in weight detection. Therefore, by inputting the output Z when there is no load immediately before the weight measurement, it is necessary to perform a zero reset corresponding to the change in the output of the load cell 18 when there is no load and to eliminate the error. In the present embodiment, the lid opening / closing detection means 21 detects the lid opening, and the pot detection means 16 determines that there is no load when the pot 12 is not set in the rice cooker body 10 and performs input when no load is applied. Reset to zero.

  The operation at this time will be described with reference to FIG. FIG. 2 is a main part flowchart showing the operation of the microcomputer 100 of the rice cooker of the present embodiment.

  In step 301, it is detected whether or not the lid 20 is open. If the lid 20 is not open, the process is terminated. If the lid 20 is open, the process proceeds to step 302. In step 302, the presence / absence of the pan 12 is detected. If there is no pan 12, the process proceeds to step 303. In step 303, the weight detection means 40 measures the weight input value Z to the microcomputer 100 when there is no load. The value is stored in the zero value storage means 206.

  Next, if there is a pan 12, the process proceeds to step 305. In step 305, since the pan 12 is set in the rice cooker body 10, the weight input value to the microcomputer 100 based on the weight of the pan 12 and the food in the pan 12 is input. M is measured, and in step 306, the weight M1 of the cooked food is calculated by the above equation (1). Here, the weight N1 of the pan 12 is stored in the pan weight storage means 205 at the time of shipment from the factory, and the no-load output Z of the weight detection means 40 is stored in the zero value storage means 206 in step 304. Therefore, the weight M1 of the cooked food can be obtained from the equation (1). Various processes can be performed according to the weight M1 of the cooked food in the pan 12 thus calculated.

  Here, the pan detection means 16 and the lid open / close detection means 21 are always in operation when the rice cooker is turned on, and output an on signal or an off signal. The hour output Z is always stored in the zero value storage means 206 and can always be reset to zero.

  As described above, in the present embodiment, the lid opening / closing detection means 21 for detecting the opening / closing of the lid 20 detects the opening of the lid and the pot detection means 16 for detecting the presence / absence of the pot 12 detects that the pot 12 is not present. In this case, the output value of the weight detection means 40 for detecting the total weight of the pot 12 and the weight of the food 19 placed in the pot 12 is stored in the zero value storage means 206 as a no-load value (zero value). Since the lid 20 is open and the pan 12 is not set in the rice cooker body 10, it is in a no-load state. Therefore, the value detected by the weight detection unit 40 at that time is set as a zero value and the zero value storage unit 206 Even if the zero value shifts due to temperature or aging, the zero value is memorized every time it is used, so that the output value shifts due to the ambient temperature and aging deterioration automatically without pressing the clear key. Correct It can, it is possible to improve the usability.

  In the first embodiment, a switch is used for the pan detection means 16, but other means such as driving induction heating to detect the pot based on the waveform difference, or the weight detection means 40 are used. Needless to say, when the weight applied to the weight detecting means 40 is smaller than a certain value, it is possible to use means for determining that there is no pan.

(Embodiment 2)
FIG. 6 is a block diagram of a rice cooker according to Embodiment 2 of the present invention.

  As shown in FIG. 6, the zero value stability detecting means 207 has a zero value only when the zero value is stably input for a certain time (for example, 1 second) and a similar value (for example, within α) is input. The storage unit 206 is configured to store a zero value. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation and action of the above configuration will be described with reference to FIG. FIG. 7 is a main part flowchart showing the operation of the microcomputer 100 of the rice cooker of the present embodiment. In addition, since the operation | movement of step 301-306 is the same as the operation | movement of the said Embodiment 1, description is abbreviate | omitted.

  In step 303, the weight input value Z to the microcomputer 100 when there is no load is measured by the weight detection means 40. If the variation in the input of the microcomputer 100 when there is no load for one second is within α in step 307, the input is stabilized. The process proceeds to step 304, and the zero value storage means 206 stores the zero value. If the variation is large in step 307, the value is not stable, so the process is terminated without storing the value.

  As described above, in the present embodiment, the zero value stability detection unit 207 that stores the zero value in the zero value storage unit 206 only when the value of the zero value is stable for a certain period of time and the same value is input. Therefore, even when the zero value is not stabilized due to vibration or the like, an accurate zero value can be input and stored by inputting after the zero value is stabilized.

  The rice cooker according to the present invention can automatically correct the deviation of weight detection due to ambient temperature and aging deterioration, and can improve the usability, so it has a function of detecting the weight of the food put in the pan. It is useful as a rice cooker.

The block diagram of the rice cooker of Embodiment 1 of this invention Side view of the rice cooker partially cut away The figure which shows the operation and the display part of the rice cooker Main circuit diagram of the rice cooker Main part flow chart of the rice cooker The block diagram of the rice cooker of Embodiment 2 of this invention Main part flow chart of the rice cooker

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rice cooker main body 12 Pan 15 Temperature detection means 16 Pot detection means 20 Lid 21 Lid open / close detection means 40 Weight detection means 201 Heating means 204 Timing means 205 Pot weight storage means 206 Zero value storage means

Claims (2)

A rice cooker body having an open top surface, a pan detachably accommodated in the rice cooker body, a lid that covers the top opening of the rice cooker body so as to be openable and closable, a heating means for heating the pan, and cooking Temperature detecting means for detecting the temperature of the object, time measuring means for measuring time, weight detecting means for detecting the total weight of the pan and the weight of the food put in the pan, and storing the weight of the pan Pan weight storage means, lid open / close detection means for detecting the opening / closing of the lid, pan detection means for detecting the presence / absence of the pan, the lid open / close detection means detects lid opening, and the pot detection means is a pan A rice cooker comprising zero value storage means for storing the output value of the weight detection means as a value (zero value) at the time of no load when it is detected that there is no food. 2. The rice cooker according to claim 1, wherein a zero value stability detecting means for storing the zero value is added to the zero value storage means only when the value of the zero value is stable for a predetermined time and the same value is inputted.

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