JP2006334126A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress unnecessary consumption of power by detecting an empty pot or the state similar and preventing continuous heating in the state in a rice cooker having a function of detecting the weight of cooked food contained in the pot. <P>SOLUTION: The pot 12 is detachably housed in a rice cooker main body 10 having an open top, and the open top 20 of the rice cooker main body 10 is covered in an openable and closable state. A heating means 201 heats the pot 12. A weight detection means 204 detects the weight of the cooked food contained in the pot 12, and a weight judgment means 206 compares the weight detected by the weight detection means 204 with a value to be compared stored in advance to judge the weight. The heating means 201 stops heating based on the judged result of the weight judgment means 206. <P>COPYRIGHT: (C)2007,JPO&INPIT

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, when this type of rice cooker detects that the pan to be stored in the rice cooker body is not put, heating is not performed. For example, in the case of an induction heating rice cooker, if it is determined that the current value for detecting the current flowing through the inverter is smaller than a predetermined value, it is determined that there is no pan, and induction heating is stopped (for example, Patent Document 1). reference).
Japanese Patent Laid-Open No. 11-76049

  However, in such a conventional rice cooker, the presence or absence of a pan can be determined, but it cannot be determined whether there is a cooked item such as rice or water in the pan, and therefore there is no cooked item, that is, an empty pan It was in a state where it could be heated even if it remained.

  If the user forgets to set the food in the pan and starts cooking, the operation is continued for several tens of minutes according to the cooking sequence. As a result, there was a problem that the electric power was simply wasted.

  In addition, some rice cookers have a heat retention function, but during the heat insulation, even if the user leaves the rice and the rice goes out of the pan, it cannot be detected, so the user can keep the heat insulation state. Until it was manually canceled, the heating operation was kept at a constant temperature, and power was simply wasted.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and has an object to detect an empty pan or a state close thereto, to prevent continued heating in that state, and to suppress wasteful power consumption.

  In order to achieve the above-mentioned 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 by a lid, and heats the pan by heating means. The weight of the food in the pan is detected by the weight detection means, the weight detected by the weight detection means is compared with the comparison value stored in advance by the weight determination means, and the weight is determined. The means is configured to stop heating based on the determination result of the weight determination means.

  Thereby, the weight determination means can determine the empty pan or a state closer to it than the weight detected by the weight detection means, and can stop heating in response to the result. It is possible to prevent the heating from being continued, and wasteful power consumption can be suppressed.

  The rice cooker of the present invention can determine an empty pan or a state closer to it from the weight detected by the weight detection means by the weight determination means, and can stop the heating in response to the result, so rice cooking, heat retention, etc. Therefore, it is possible to prevent the heating in an empty pan or a state close thereto, and to suppress wasteful power consumption.

  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, weight detection means for detecting the weight of the food put in the pan, weight determination means for comparing the weight detected by the weight detection means with a comparison value stored in advance and determining the weight The heating means stops heating based on the determination result of the weight determination means, and the weight determination means determines an empty pan or a state closer thereto than the weight detected by the weight detection means. Because it can stop the heating in response to the result, it can be prevented to continue heating in an empty pan or near it with rice cooking or heat insulation, etc., and wasteful power consumption is suppressed. Can do.

  According to a second invention, there is provided display means for performing a display operation in the first invention, wherein the display means is configured to display based on a determination result of the weight determination means, and the user displays the display. By checking, you can recognize that you are in an empty pan or near it.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a lid opening / closing detection unit that detects opening / closing of the lid is provided, and the weight determination unit is configured to determine when the lid opening / closing detection unit detects the lid closing. Therefore, when the user closes the lid of the rice cooker, an empty pot or a state close thereto can be determined.

  In a fourth aspect of the present invention, in the first aspect of the invention, when the weight determination unit determines that the weight exceeds the comparison value, heating by the heating unit is permitted, and the pan is close to it. After the state is determined and the heating is stopped, the heating can be resumed by setting the pot containing the cooked product again in the rice cooker body.

  According to a fifth aspect of the present invention, there is provided the comparison value changing means for changing the comparison value stored in the weight determination means in the first invention, so that the comparison value stored in the weight determination means can be easily obtained. Can be changed.

  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.

  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 part 30 of the rice cooker body 10 is composed of an upper upper frame 32 and a lower coil base 31, and the storage part 30 detachably stores the pan 12 made of a magnetic material. 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 control unit 203, a display unit 207, and the like that configure the heating unit 201, and controls the operation of the heating coil 13 that configures the heating unit 201. The pot 12 is induction-heated, and the food 19 in the pot 12 is heated and cooked. Here, the control means 203 is realized by a microcomputer 100 (hereinafter referred to as a microcomputer) shown in FIG. The microcomputer 100 also includes a signal conversion unit 205 constituting the weight detection unit 204 and a weight determination unit 206 for determining the weight.

  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 pan temperature detecting means 15 is disposed at the bottom of the coil base 31 and detects the temperature of the pot 12. When the pan 12 is stored in the storage portion 30, the pot temperature detecting means 15 is the bottom of the pot 12. The temperature of the cooked food 19 is detected by detecting the temperature of the pan 12, and the output is input to the control means 203.

  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 lid open / close detection means 21 is always operating when the rice cooker is turned on, and outputs an on signal or an off signal.

  The weight detection unit 40 constituting the weight detection unit 204 detects the total weight of the pan 12 and the food 19 placed in the pan 12. The main parts of the weight detection unit 40 are the support unit 17 and the load cell 18. The load cell 18 is a robust load cell (load converter), and is rigidly connected to the rice cooker body 10. 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 unit 40 is configured to accurately measure the weight of the pan 12 and the object to be heated (the cooked object 19) through the support unit 17 that supports the bottom surface of the pan 12 at three points.

  Electric signals from the pan temperature detecting means 15, the lid open / close detecting means 21, and the weight detecting section 40 are input to the circuit board 14, respectively.

  FIG. 3 is a circuit diagram of the circuit board 14 of the present embodiment. As shown in FIG. 3, 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 pan temperature detecting 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 liquid crystal display panel 53 and the lamp 52 constitute display means 207 to perform a display operation.

  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 of weight detection in the above configuration will be described. The output of the weight detector 40 is output even when the pan 12 is not loaded in the rice cooker body 10. The input to the microcomputer 100 at the time of no load of the weight detection unit 40 is Z, and the input when the pan 12 is set in the rice cooker body 10 (nothing is contained in the pan 12) per N, 1g If the microcomputer input is m, the weight N1 of the pan 12 is
N1 = (NZ) / m
It becomes.

  The input Z to the microcomputer 100 at the time of no load and the weight N1 of the pan 12 are stored in the signal conversion means 205. This storage of Z and N1 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 body 10 and the food 19 is contained in the pan 12 and the input to the microcomputer 100 of the weight detector 40 is M, the weight M1 of the cook 19 is
M1 = (M−Z) / m−N1 (1)
It becomes. The signal conversion unit 205 converts the signal from the weight detection unit 40 into a weight value according to the equation (1).

  The weight value detected by the weight detection unit 204 is input to the weight determination unit 206. The operation of the weight determination means 206 will be described with reference to the flowchart of FIG.

  In step 101, the lid opening / closing detection means 21 determines whether the lid 20 is open. If it is open, the process proceeds to step 102 where the weight value detected by the weight detection means 204 is compared with a predetermined comparison value.

  In the rice cooker, there is a range of the number of cups that can be cooked. Here, the range of the number of cups that can be cooked is 0.5 cup to 5.5 cups. That is, since the minimum number of cups is 0.5 cup, the cooked food 19 that can be cooked in the pan 12 is compared by comparing a weight value smaller than the total value of the weight of rice and the weight of water at that time. You can determine if it is in. The rice weight of 0.5 cup is about 75g, and if the amount of water required when cooking 0.5 cup is 160cc, the weight is about 160g, so if the total is 235g or more, rice can be cooked become. In step 102, it is determined whether or not the weight is 200 g or less, which is smaller than 235 g. If it is less than that, it is determined that the pan is in an empty pan or a state close thereto, and in step 103, a heating stop signal is sent to the control means 203. Output.

  As described above, if the weight of the food 19 is 200 g or less, it can be determined that the pot is in an empty pan or a state close thereto, and the weight determination means 206 outputs a heating stop signal to the control means 203 constituting the heating means 201. The control means 203 can stop outputting the drive signal to the drive means 202 when receiving the signal.

  In the present embodiment, since the comparison value of the weight determination means 206 is set to a value that takes into account the minimum value of the number of cups that can be cooked, heating is stopped if the value is less than that value, and if the value is exceeded, normal You can cook rice.

  Here, in the operation of the weight determination unit 206 of the present embodiment, the weight is determined only when the lid 20 is opened by the lid opening / closing detection unit 21, which is the rice cooker of the present embodiment. This is because when the lid 20 is closed, the lid 20 presses the pan 12 from above, so that the weight of the food 19 cannot be detected when the lid 20 is closed. Needless to say, the lid opening / closing determination is not necessary unless the pan 12 is pressed from above when the lid 20 is closed.

  As described above, in the present embodiment, the weight of the food 19 placed in the pan 12 is detected by the weight detection means 204, and the weight detected by the weight detection means 204 and the comparison value stored in advance are stored. Since the weight is determined by the weight determination unit 206 and the heating unit 201 stops heating based on the determination result of the weight determination unit 206, the weight detected by the weight detection unit 204 by the weight determination unit 206. Since it is possible to judge the state of the empty pan or a state closer to it, and stop the heating in response to the result, it is possible to prevent the heating in the state of the empty pan or near it from being cooked or kept warm. This can reduce wasteful power consumption.

  In the present embodiment, the signal conversion means 205 constituting the weight detection means 204 detects the weight of the cooked food 19 only from the output of the weight detection section 40 and the weight determination means 206 determines the weight. However, of course, the determination may be made based on the total weight of the pan 12 and the food 19.

(Embodiment 2)
The display means 207 shown in FIG. 1 turns on the lamp 52 constituting the display means 207 when the weight determination means 206 determines that the weight is equal to or less than the comparison value based on the determination result of the weight determination means 206. It is configured. Other configurations are the same as those of the first embodiment.

  Thus, when the heating means 201 stops heating, the user can recognize that the cooked food 19 is not contained in the pan 12 by confirming that the lamp 52 is lit.

  As described above, in the present embodiment, since the display unit 207 displays based on the determination result of the weight determination unit 206, the user confirms the display so that the empty pan or a state close thereto is displayed. Can recognize that

  In this embodiment, the lamp 52 is used for display, but it goes without saying that the same effect can be obtained even when the liquid crystal display panel 53 is used for display.

(Embodiment 3)
The weight determination means 206 shown in FIG. 1 is configured to determine the weight when the lid opening / closing means 21 detects a closed state from the open state of the lid 20. Other configurations are the same as those in the first or second embodiment.

  In the above configuration, the operation of the weight determination means 206 will be described with reference to the flowchart of FIG.

  In step 104, the lid opening / closing detection means 21 determines whether or not the lid 20 has changed from an open state to a closed state.

  The lid opening / closing detection means 21 is adjusted so as to detect the lid closed state immediately before the lid 20 is closed and a load is applied to the pan 12, so that the cooked food accurately after detecting the lid closed state from the lid open state. 19 weights can be detected.

  Thus, the weight determination means 206 performs determination when the lid 20 is closed. Since the user normally takes out the pan 12 or prepares rice cooking when the lid 20 is opened, an unnecessary judgment can be omitted by making a judgment when the lid 20 is closed. The lamp 52 can be prevented from being lit when the lid 20 is open.

  As described above, in the present embodiment, the weight determination unit 206 determines the weight when the lid open / close detection unit 21 detects the lid closed, so the user closed the lid 12 of the rice cooker. Sometimes it can be determined whether the pan is close to it.

(Embodiment 4)
The weight determination unit 206 shown in FIG. 1 is configured to determine that the weight has increased when it is determined that the weight is below the comparison value and then exceeds the comparison value, and to allow the heating unit 201 to perform heating permission. is doing. Other configurations are the same as those of the first embodiment.

  In the above configuration, the operation of the weight determination means 206 will be described with reference to the flowchart of FIG.

  In step 101, the lid opening / closing detection means 21 determines whether the lid 20 is open. If it is open, the process proceeds to step 102. In step 102, it is determined whether or not the weight is 200 g or less, and if it is 200 g or less, it is determined that the pan is close to it or not, and in step 103, a heating stop signal is transmitted to the control means 203. Output to. If the weight exceeds 200 g in step 102, the process proceeds to step 105, and it is determined whether the weight has changed from a state of 200 g or less to a state of exceeding 200 g. When the weight changes from 200 g or less to over 200 g, the routine proceeds to step 106 and a heating permission signal is output to the control means 203.

  In this way, once it is determined that the weight is 200 g or less and the heating means 201 has stopped heating, the cooked food 19 is again placed in the pan 12 and set in the rice cooker body 10 to return to heating permission. Can do.

  As described above, in the present embodiment, when the weight determining unit 206 determines that the weight exceeds the comparison value, the heating by the heating unit 201 is permitted. Then, after heating is stopped, heating can be resumed by setting the pot 12 containing the cooked food 19 again in the rice cooker body 10.

  In the present embodiment, it is determined in step 105 that the weight has increased by determining whether the weight has changed from 200 g or less to a state exceeding 200 g, but a heating stop signal is output. In the state, it may be determined whether or not the weight exceeds 200 g, and similar actions and effects can be obtained.

(Embodiment 5)
The comparison value stored in the weight determination unit 206 shown in FIG. 1 can be changed by the comparison value changing unit 208. Other configurations are the same as those of the first embodiment.

  The comparison value changing unit 208 divides the power supply voltage generated by the power supply IC 106 by a resistor and inputs the divided voltage to an AD converter built in the microcomputer 100, and the comparison value stored in the weight determination unit 206 based on the AD conversion result. To change. Here, a value twice the conversion result when the AD converter applies a predetermined voltage to the AD converter with 8-bit accuracy is changed as a comparison value of the weight determination means 206. That is, when the AD conversion result is 90 (0x5A in hexadecimal), the double 180 is changed as the comparison value, and when the AD conversion result is 105 (0x69 in hexadecimal), the double. 210 is changed as a comparison value.

  Thus, when the lower limit of the number of cups in the possible range of rice cooking is changed, the comparison value stored in the weight determination means 206 can be freely changed.

  As described above, in the present embodiment, since the comparison value changing unit 208 for changing the comparison value stored in the weight determination unit 206 is provided, the comparison value stored in the weight determination unit 206 can be easily obtained. Can be changed.

  As mentioned above, since the rice cooker concerning this invention can determine an empty pot or a state close to it, and can stop a heating in response to the result, it is an empty pot or near it by rice cooking or heat insulation. Since it is possible to prevent the heating in the state from being continued, and wasteful power consumption can be suppressed, it is useful as a rice cooker having a function of detecting the weight of the cooked food put in the pan.

The block diagram of the rice cooker of Embodiment 1 of this invention Side view of the rice cooker partially cut away Main part circuit diagram of the rice cooker partially block Operation flowchart of weight determination means of the rice cooker Operation flowchart of weight determination means of rice cooker according to embodiment 3 of the present invention Operation flowchart of weight determination means of rice cooker according to embodiment 4 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rice cooker main body 12 Pan 20 Lid 201 Heating means 204 Weight detection means 206 Weight determination means

Claims (5)

A rice cooker body having an open top surface, a pan that is detachably stored in the rice cooker body, a lid that covers the top opening of the rice cooker body in an openable and closable manner, a heating means that heats the pan, and A weight detecting means for detecting the weight of the food put in the pan; and a weight determining means for comparing the weight detected by the weight detecting means with a comparison value stored in advance to determine the weight, and the heating The means is a rice cooker that stops heating based on the determination result of the weight determination means. The rice cooker according to claim 1, further comprising display means for performing a display operation, wherein the display means displays based on a determination result of the weight determination means. The rice cooker according to claim 1 or 2, further comprising lid opening / closing detection means for detecting opening / closing of the lid, wherein the weight determination means determines when the lid opening / closing detection means detects lid closing. The rice cooker according to claim 1, wherein when the weight determination means determines that the weight exceeds the comparison value, heating by the heating means is permitted. The rice cooker of Claim 1 provided with the comparison value change means which changes the comparison value memorize | stored in the weight determination means.