JP2009233229A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker capable of detecting the temperature of a heating element by a non-contact type temperature sensor and appropriately controlling the rice cooking using the detection signal. <P>SOLUTION: This rice cooker has an inner pot, an inner case for storing the inner pot, a work coil for heating the inner pot, the heating element provided at the bottom of the inner pot in a form facing the work coil, and the temperature sensor, wherein the temperature sensor is disposed facing the heating element in non-contact therewith. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature sensor for an induction heating rice cooker.

  Generally, a rice cooker has a plurality of heating means such as an induction coil, a heat retaining heater, and a lid heater, and it is very convenient to automatically cook rice and heat by using these heating means to provide the optimum rice to the user. It is widely known as an instrument.

  The present applicant has already marketed rice cookers that use inner pots as earthen pots, for example, and has filed many related patents. This clay pot rice cooker has the same control process as that of a metal pot. An example of the process will be described with reference to FIG. As shown in the figure, the rice cooking process consists of a water absorption process for absorbing sufficient water into the rice, a temperature rising and cooking process for raising the heat and cooking rice, and a subsequent uneven rice process. And a heat insulation process after the rice cooking process, and in each process, a plurality of heating means such as a work coil, a heat insulation heater and a lid heater detect the temperature of the inner pot based on the detection signal of the temperature sensor. The output is controlled and optimal process control is performed.

  Since the earthenware pot has a larger heat capacity than that made of metal, the rate of temperature rise during cooking is relatively gentle, and the heat storage property is good, so that cooked rice can be cooked deliciously. Moreover, when there is unprocessed rice in the inner pot, the whole inner pot can be reheated in a microwave oven, and since heat storage is good, there is an advantage that a warm state can be maintained for a long time after reheating.

  By the way, since the earthenware pot has poor heat response as described above, the earthenware pot cooking is performed with a conventional center sensor, i.e., a contact-type temperature sensor that detects the temperature by contacting the tip of the earthenware pot with the center of the bottom, It had the disadvantage that the accuracy was inferior to that of a metal pan.

  In order to solve the above problems, the present applicant has filed an application shown in FIG. That is, a heating element 3 made of a metal such as silver is provided at the bottom 1a of the earthenware pot 1 so as to face the work coil 2, and a conductive material 4 such as aluminum is provided at the center of the bottom 1a. The center sensor 5 which is a temperature sensor is provided in a form in contact with the center. With such a configuration, the temperature of the earthenware pot 1 is transmitted to the center sensor 5 via the conductive material 4 earlier to increase the detection accuracy (see, for example, Patent Document 1).

However, the above-mentioned conventional example is not necessarily sufficient even if accuracy is improved, for example, when moving from the cooking process to the uneven process, or when there is a cooking process, when shifting to the cooking process, Since there is no water and the temperature of the earthenware pot rises rapidly, it is necessary to detect the temperature immediately. However, the conventional example has a problem that it is difficult to detect the rapid temperature increase immediately. It was.
JP2007-319250A

  The objective of this invention is detecting the temperature of a heat generating body with a non-contact-type temperature sensor, and is providing the rice cooker which can perform more proper rice cooking control using the detection signal.

  In order to achieve the above object, the present invention adopts the following configuration.

  In the invention which concerns on Claim 1, it is provided in the form which opposes the said work coil in the bottom part of the said inner pot, the inner case which accommodates the said inner pot, the work coil for heating the said inner pot, and the said inner pot. The rice cooker which has a heat generating body and a temperature sensor, The said temperature sensor opposes the said heat generating body, and is a structure arrange | positioned in a non-contact state.

  In the invention which concerns on Claim 2, the heat-resistant plate which has a through-hole or a non-through-hole is provided between the bottom part of the said inner pot and the said inner case, and the front-end | tip of the said temperature sensor faces the said heat generating body with the said form. The structure provided in a through-hole or the non-through-hole.

  In the invention which concerns on Claim 3, the said temperature sensor detects the cooking temperature, and the subsequent unevenness process is performed using this detection signal.

  In the invention which concerns on Claim 4, the said work coil is divided | segmented into a central part and an outer peripheral part with a clearance gap, and the lead wire of the said temperature sensor is taken out from the said clearance gap.

  And by these structures, the rice cooking control which followed the temperature of the heat generating body is attained.

  The invention which concerns on Claim 1 can perform appropriate rice cooking control corresponding to the temperature of a heat generating body by making a temperature sensor face a heat generating body in the non-contact state. In particular, if there is a transition from the cooking process to the unevenness process, or if there is a cooking process, the transition to the cooking process can be performed smoothly. It can be carried out.

  In the invention according to claim 2, the heat-resistant plate provided between the bottom of the inner pot and the inner case is provided with a through-hole or a non-through-hole, and the tip of the temperature sensor is opposed to the heating element in the form of the through-hole or non-through. By providing in the mouth, a part or the whole of the temperature sensor is covered with a heat resistant plate, and the heat resistance of the temperature sensor can be improved. Moreover, since the temperature sensor can be attached using a heat-resistant plate, the attachment can be facilitated.

  The invention which concerns on Claim 3 can perform rice cooking control appropriately by detecting cooking temperature with a temperature sensor, and performing the subsequent uneven process. Further, more appropriate rice cooking control can be performed by using the conventional contact temperature sensor and the non-contact temperature sensor of the present invention in combination.

  The invention according to claim 4 can facilitate the arrangement of the lead wires by dividing the work coil into a central portion and an outer peripheral portion in a form that allows a gap, and taking out the lead wire of the temperature sensor from the gap. . Furthermore, the adverse effect of the magnetic field on the temperature sensor can be reduced.

  1 shows an overall vertical cross-sectional view of the rice cooker, FIG. 2 shows an enlarged cross-sectional view near the bottom of the inner pot in FIG. 1, FIG. 3 shows an enlarged cross-sectional view near the bottom of the other inner pot, and FIG. The expanded sectional view of the other inner pot bottom vicinity vicinity is shown. The inner pot of the rice cooker may be made of metal, but will be described as a clay pot below.

  The whole rice cooker 10 is shown in FIG. The rice cooker 10 includes a main body 11 and a lid 30. The rice cooker main body 11 has an outer case 12 made of an integrally molded product made of synthetic resin, and an earthen pan 13 which is an inner pot made of ceramic is detachably set in the outer case 12. An inner case 14 that is a protective frame along the shape of the earthenware pot 13 is provided outside the earthenware pot 13. The inner case 14 is made of a heat-resistant synthetic resin such as polyethylene terephthalate, for example, and a sensor insertion hole 15a for allowing the center sensor 15 made of a thermistor to face is formed at the center of the bottom.

  The upper end of the inner case 14 is integrally coupled to the upper end of the outer case 12 via a shoulder member 16, and a space portion 17 is formed inside the outer case 12, the inner case 14, and the shoulder member 16. A bottom work coil 18 and a side work coil 19 for induction heating the earthenware pot 13 are provided outside the inner case 14. The bottom work coil 18 and the side work coil 19 are respectively provided concentrically around the center of the bottom of the inner case 14 at each position of the curved portion from the bottom of the inner case 14 to the peripheral side. Yes.

  A synthetic resin coil support 20 is provided outside the bottom work coil 18 and the side work coil 19, and the bottom work coil 20 is attached to the inner case 14 with screws or the like. 18 and the side work coil 19 are positioned and fixed at predetermined positions shown in the figure. A ferrite core 20 a for confining a magnetic field is provided outside the coil support 20. A heat retaining heater 22 is provided on the outer peripheral side of the upper part of the inner case 14.

  The earthenware pan 13 is made of ceramics such as fired ceramics or glass, and a ring-shaped leg portion 13 a that contacts the bottom of the inner case 14 is formed on the bottom of the earthenware pot 13. The legs 13a are not limited to the ring shape, but may be formed locally or radially.

  The leg portion 13a is provided between the bottom work coil 18 on the bottom side of the inner case 14 and the side work coil 19 on the curved portion side, and has a certain clearance S1 between the inner case 14 (FIG. 2). Is formed at a predetermined height so as to occur. Further, the earthenware pot 13 is provided with a bottom heating element 18a and a side heating element 19a made of a metal film at locations facing the bottom work coil 18 and the side work coil 19, respectively.

  And in the said clearance gap S1 between the earthenware pan 13 and the inner case 14, the heat-resistant plate 21 is provided. The heat-resistant plate 21 is a disk-shaped heat-resistant member having a through-hole 21a in the center, and prevents heat from the bottom heating element 18a from being transmitted downward.

  The bottom heating element 18a and the side heating element 19a are formed, for example, by applying and baking a silver paste or the like. Since the leg 13a of the earthenware pan 13 has an uneven surface, it is difficult to form a heating element. However, the leg 13a is formed at the opposite position of the bottom work coil 18 and the side work coil 19. Because it is out of position, there is no effect on rice cooking performance. The heating element may have a structure in which a metal object such as copper foil or stainless steel net is embedded in advance in the earthenware pot 13 in advance.

  When the rice cooking switch is turned on, the bottom heating element 18a and the side heating element 19a are heated by the Joule heat caused by the eddy current induced by the bottom work coil 18 and the side work coil 19, and the clay pot is heated by the heating of both heating elements. 13 is heated.

  Furthermore, the center part with which the center sensor 15 of the bottom part of the earthenware pot 13 contact | abuts is formed a little thinly so that intensity | strength may not be impaired rather than another part. By making the central portion of the earthenware pan 13 thin, heat from the bottom heating element 18a and the side heating element 19a is easily conducted to the central portion of the thin wall, so that the detection accuracy of the center sensor 15 can be increased. The energizing power to the bottom work coil 18 and the side work coil 19 can be controlled appropriately.

  Reference numeral 23 denotes an operation panel constituting an operation unit. The operation panel 23 includes, for example, a rice cooker switch, a heat retention switch, a menu switch for setting various menus such as white rice, quick cooking, and no-wash rice, and a timer switch for setting time. In addition, various switches 24 such as a cancel switch for canceling the setting and a liquid crystal display unit 25 are provided.

  Reference numeral 26 is a microcomputer board on which a microcomputer is mounted, 27 is a power board on which a power circuit having an inverter and the like for controlling energization to the bottom work coil 18 and the side work coil 19 is mounted, and 28 is each of the above-mentioned A substrate cooling fan for cooling the substrates 26 and 27.

  The lid body 30 includes a lid upper member 31 and a lid lower member 32. The lid upper member 31 is a resin member forming an outer peripheral surface, and has a pressure adjusting unit 33 at the center thereof. The lid lower member 32 has a metal heat radiating plate 34 at the center thereof, and a lid sensor 35 for detecting the temperature in the clay pot 13 is attached to the heat radiating plate 34 and a lid heater (not shown) is attached. The inside of the clay pot 13 is heated from above. The pressure adjusting unit 33 includes a steam passage 36 and a steam valve 37 inside, and regulates the internal steam pressure.

  The lid body 30 is pivotally supported by applying a force in the opening direction to a hinge mechanism 38 provided behind the rice cooker 10, and is opened by pressing a lock member 39 provided in front of the rice cooker 10. .

  A microcomputer control unit is provided on the microcomputer board 26 on which the microcomputer is mounted, and rice cooking and heat retention control shown in the time chart of FIG. 6 are performed.

  That is, in the rice cooking process, by increasing the outputs of the bottom work coil 18 and the side work coil 19 to predetermined values, a water absorption process is first performed for causing the rice to absorb water. When enough water is absorbed in the rice, the output is rapidly increased and the temperature rising process is performed to cook the rice at once. The amount of cooked rice in the inner pot is based on the temperature rising time in this temperature increasing process. The total number is determined, and the subsequent cooking time is determined based on the total number of cooked rice. After the cooking process, the rice cooked in the uneven process is sufficiently uneven, the rice is brought into an optimal state, and the rice cooking process is completed. When the rice cooking process is completed, the process moves to a heat retaining process, and the heat is kept for a predetermined time. These controls are performed by executing a predetermined program stored in the memory of the microcomputer.

  The temperature sensor 40 of the present invention will be described. In FIG. 1 and FIG. 2, a through hole 41 is provided in the heat-resistant plate 21, and a temperature sensor 40 is provided in the through hole 41. The heat-resistant plate 21 is provided with a through hole 41 at a position shifted from the center to the outer periphery, and a temperature sensor 40 is attached to the through hole 41.

  The temperature sensor 40 is a T-shaped member having a small-diameter portion 40a and a large-diameter portion 40b, the periphery of which is covered with a polymer resin. The distal end of the small-diameter portion 40a is a distal end portion 42. Has an embedded thermistor. A lead wire 43 is connected to the thermistor, and the lead wire 43 is pulled out and connected to a power source (not shown).

  The temperature sensor 40 is attached as follows. As described above, the heat resistant plate 21 is provided with the through hole 41, and the small diameter portion 40 a of the temperature sensor 40 is fitted into the through hole 41. The inner diameter of the through hole 41 is slightly larger than the small diameter part 40 a of the temperature sensor 40, and the small diameter part 40 a easily fits into the through hole 41. When the small diameter portion 40 a is fitted into the through hole 41, the tip end portion 42 protrudes upward, for example, by about 0.5 mm from the upper surface of the heat resistant plate 21.

  When the small diameter portion 40 a is fitted into the through hole 41, the upper surface of the large diameter portion 40 b comes into contact with the lower surface of the heat resistant plate 21. In such a state, the heat-resistant plate 21 is placed on the upper surface of the inner case 14. Then, the lower surface of the temperature sensor 40 comes into contact with the upper surface of the inner case 14, and the temperature sensor 40 is held between the upper surface of the inner case 14 and the lower surface of the heat resistant plate 21. Thereafter, the upper surface of the inner case 14 and the lower surface of the heat-resistant plate 21 are bonded with an adhesive, and the temperature sensor 40 is fixed. With such an attachment form, in particular, an attachment member for the temperature sensor 40 can be eliminated, and the attachment can be easily performed. The lead wire 43 is taken out from the side surface of the large diameter portion 40b.

  By the way, the center sensor 15 is fitted into the sensor insertion hole 15a at the center of the heat-resistant plate 21 with a gap, and the temperature sensor 40 is also inserted into the through-hole 41 provided at a position eccentric from the center of the heat-resistant plate 21. When water enters the inner case 14 after the earthenware pan 13 is taken out, the water enters the inner case 14 through the sensor insertion hole 15a and the through hole 41. A plurality of drain holes 44 are provided in the circumferential direction substantially at the center of the bottom, and water that has entered the inner case 14 is discharged from the drain holes 44. In particular, drainage can be facilitated by providing the through hole 41 above or near the drainage hole 44.

  By attaching the temperature sensor 40 to the heat-resistant plate 21 in this manner, the tip 42 of the temperature sensor 40 penetrates the through hole 41 and has a gap in the vicinity of the bottom heating element 18a at the bottom of the earthenware pan 13 so as to be non-existent. It will be opposed in the state of contact, and the temperature of the bottom heating element 18a can be detected more reliably. In addition, by setting it as such a form, the clearance gap between the front-end | tip part 42 of the temperature sensor 40 and the bottom part heat generating body 18a can be freely set as needed.

  FIG. 3 shows another mounting structure of the temperature sensor 40. The thing of FIG. 3 provides the recessed part 45 which protruded upwards in the lower surface of the heat-resistant plate 21 instead of the through-hole 41 in the heat-resistant plate 21, and attaches the temperature sensor 40 to this recessed part 45. FIG. The recess 45 is provided upward from below the heat-resistant plate 21, and the thickness of the heat-resistant plate 21 remaining above the recess 45 is set to ½ or less of the total thickness of the heat-resistant plate 21.

  The front end portion 42 of the temperature sensor 40 is attached in a form that comes into contact with the upper surface of the recess 45. The mounting of the temperature sensor 40 is almost the same as that of FIG. By adopting such a configuration, the temperature of the bottom heating element 18a can be detected. By adopting such a configuration, the distal end portion 42 of the temperature sensor 40 is not directly exposed to the high heat of the bottom heating element 18a, and adverse effects caused by the direct exposure can be reduced. For example, it becomes possible to use a resin having lower heat resistance.

  4 and 5 show still another mounting structure of the temperature sensor 40. FIG. The temperature sensor 40 has a lead wire 43, and in order to connect the lead wire 43 to, for example, a power source, it is necessary to secure a place where the lead wire 43 is pulled out. When it arrange | positions to, taking out of the lead wire 43 becomes difficult. The thing of this example can respond to such a bad effect.

  That is, as shown in FIG. 5, the bottom work coil 18 is divided into a central portion 18b and an outer peripheral portion 18c, and a gap 18d is provided between both portions 18b and 18c, and the lead wire 43 is taken out from the gap 18d. It is.

  By adopting such a configuration, the lead wire 43 can be easily taken out, and the bottom work coil 18 is not positioned below the temperature sensor 40, so that the adverse effect of the magnetic field on the temperature sensor 40 can be reduced. In this example, the tip 42 of the temperature sensor 40 is shown in FIGS. 1 and 2 in which the heat-resistant plate 21 penetrates, but the temperature sensor 40 as shown in FIG. 3 may be used.

  The temperature sensor 40 can perform rice cooking control alone, but may be performed in combination with the center sensor 15. An example of such control will be described. In particular, the temperature sensor 40 can detect an appropriate temperature as compared with the conventional center sensor 15 that shifts from the cooking process to the unevenness process. That is, the time to shift from the cooking process to the unevenness process is the time when the water in the clay pot 13 runs out and the temperature of the bottom heating element 18a and the side heating element 19a rises rapidly, the time corresponding to the temperature H in FIG. However, the conventional center sensor 15 cannot accurately detect the rapidly rising temperatures of the bottom heating element 18a and the side heating element 19a. On the other hand, since the temperature sensor 40 is provided so as to face the bottom heating element 18a, the temperature sensor 40 can detect the temperature more accurately. Therefore, the temperature sensor 40 is used for detection of such a period, and the control of the other period is a control form in which heating control is performed based on the detection signal of the center sensor 15 as usual.

  The above-described control using the temperature sensor 40 is “control that shifts to the unevenness process when the detected value of the temperature sensor 40 reaches a predetermined temperature during the cooking process”, but other control is “during the cooking process” "When the detected value of the temperature sensor 40 reaches a predetermined change amount, the control shifts to the uneven process", "When the detected value of the temperature sensor 40 reaches a predetermined temperature during the cooking process, the additional cooking process is performed for a predetermined time. After, control to shift to the uneven process "," control to execute the additional cooking process for a predetermined time when the detected value of the temperature sensor 40 reaches a predetermined change amount during the cooking process, and to shift to the uneven process "," When the temperature sensor 40 detects a predetermined temperature during the cooking process, it is determined that the earthenware pan 13 is in an empty state and the heating is stopped. “When the temperature sensor 40 detects a predetermined change amount during the cooking process, the earthenware pot 13 is empty Determining that come state, the control of the control "such as to control the control" and "Okoge to stop heating are conceivable.

  The present invention is not limited to the configuration of the embodiment described above, and can be appropriately changed in design without departing from the gist of the invention. For example, when the heating means is a heater, the temperature sensor is opposed to the heater. The present invention can also be applied to those arranged in a non-contact state.

Whole sectional view of the rice cooker of the present invention 1 is an enlarged cross-sectional view near the bottom of the inner pot in FIG. Enlarged sectional view of the other inner pot bottom vicinity of the present invention Enlarged sectional view of still another inner pot bottom vicinity of the present invention The figure which shows the state which divided | segmented the bottom work coil of FIG. Cooking rice, heat retention process time chart Conventional center sensor installation drawing

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Rice cooker 11 ... Rice cooker main body 12 ... Outer case 13 ... Earthen pot 13a ... Leg part 14 ... Inner case 15 ... Center sensor 15a ... Sensor insertion hole 16 ... Shoulder member 17 ... Space part 18 ... Bottom work coil 18a ... Bottom heat generation Body 18b ... Central part 18c ... Outer peripheral part 18d ... Clearance 19 ... Side work coil 19a ... Side heating element 20 ... Coil support 20a ... Ferrite core 21 ... Heat-resistant plate 21a ... Through hole 22 ... Insulation heater 23 ... Operation panel 24 ... Various switches 25 ... Liquid crystal display unit 26 ... Microcomputer board 27 ... Power supply board 28 ... Cooling fan 30 ... Cover body 31 ... Cover upper member 32 ... Cover lower member 33 ... Pressure adjusting unit 34 ... Heat sink 35 ... Cover sensor 36 ... Steam passage 37 ... Steam valve 38 ... Hinge mechanism 39 ... Lock member 40 ... Temperature sensor 40a ... Small diameter portion 40b ... Large diameter portion 1 ... through hole 42 ... tip 43 ... lead wire 44 ... drain hole 45 ... recess

Claims (4)

An inner pot, an inner case for storing the inner pot, a work coil for heating the inner pot, a heating element provided in a form facing the work coil at the bottom of the inner pot, a temperature sensor, In the rice cooker having
The said temperature sensor is arrange | positioned in the non-contact state facing the said heat generating body, The rice cooker characterized by the above-mentioned.   A heat-resistant plate having a through-hole or a non-through hole is provided between the bottom of the inner pot and the inner case, and the tip of the temperature sensor faces the heating element in the form facing the heating element. The rice cooker according to claim 1, wherein the rice cooker is provided.   The rice cooker according to claim 1 or 2, wherein the temperature sensor detects a cooking temperature and performs a subsequent uneven process using the detection signal.   The rice cooker according to any one of claims 1 to 3, wherein the work coil is divided into a central portion and an outer peripheral portion with a gap, and a lead wire of the temperature sensor is taken out from the gap. vessel.

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