JP2009004212A - Induction-heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a convenient induction-heating cooker in which heat effect to an infrared ray sensor is reduced, and in which temperature control of a cooking container by the infrared ray sensor can be carried out surely. <P>SOLUTION: Since a gap 42g is installed at the surrounding and the gap 42g of the surrounding acts as a heat insulating layer so that a radiation heat and a conduction heat from a heat generating parts of the surroundings such as a pot, a coil, and a ferrite will not reach the infrared ray sensor 10 directly, the infrared ray sensor 10 is prevented from becoming to have a high temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an induction heating cooker that induction-heats a cooking container and controls the temperature of the cooking container using an infrared sensor.

In recent years, induction cooking devices have been widely used as cooking devices that do not use fire. In this induction heating cooker, an infrared sensor is arranged below the center of the heating coil, and the output of the heating coil is controlled by controlling the inverter circuit by the control means in accordance with the output from the infrared sensor (for example, Patent Documents). 1).
JP 2005-38660 A

  However, in an induction heating cooker having the above-described configuration, when a cooking container such as an empty pan (which does not contain an object to be cooked) is heated, the cooking container has the highest magnetic flux density and generates a large amount of heat during heating. Since the upper part of the middle part of the outermost and innermost windings rises rapidly, the response of the heating output control to the high temperature part of the cooking container is delayed, and a thin stainless steel pan with poor heat conduction and low heat capacity When used as a cooking container, the pan bottom may become red hot and the pan may be deformed, or a small amount of food such as oil may become hot.

  If the infrared sensor is arranged not to be in the center of the heating coil but to be able to measure the temperature of the cooking coil in the middle of the heating coil or in the vicinity of the inner circumference of the heating coil, the above-mentioned problem can be solved. Because it is placed in a place where the temperature of the cooking vessel tends to rise, for example, the infrared sensor receives the radiant heat from the cooking vessel during baking, the radiant heat from the surrounding heating parts such as coils and ferrite, and conduction heat. It had the problem of becoming severe.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an induction heating cooker in which the thermal influence on the infrared sensor is reduced.

  In order to solve the conventional problems, the induction heating cooker according to the present invention includes a main body constituting the outer shell and a cooking container mounted on the upper portion of the main body. A top plate, a heating coil that is provided below the top plate so as to face the top plate and that generates an AC magnetic field to induction-heat the cooking vessel, a coil base that holds the heating coil, An infrared sensor that is provided below the heating coil and detects infrared rays emitted from the cooking vessel, and an infrared incident region formed on the top plate so that infrared rays emitted from the cooking vessel can be transmitted from the cooking vessel. Infrared light is guided to the infrared sensor, based on a resin light guide fixed to or integrally formed with the coil base, and an output signal of the infrared sensor Control means for controlling the output of the heating coil, and the light guide section has a light guide tube and a surrounding outer wall that protrude downward, and a lower portion between the light guide tube and the outer wall. An infrared condensing lens for condensing the infrared light is disposed on the infrared sensor so as to face the lower end opening of the light guide tube.

  As a result, the surrounding gap acts as a heat insulating layer so that radiant heat and conduction heat from surrounding heat generating parts such as pans, coils, and ferrite do not reach the sensor directly, so that the sensor can be prevented from becoming hot. Moreover, since it becomes a double cylinder shape, it becomes strong also in intensity | strength, the perpendicularity of a sensor and a light guide pipe | tube improves, and the detection accuracy of a sensor can improve.

  According to the present invention, it has a light guide tube that protrudes downward and a peripheral outer wall, and a gap that opens downward is provided between the light guide tube and the outer wall, and a lower end opening of the light guide tube By arranging an infrared condensing lens for concentrating the infrared light on the infrared sensor so that the radiant heat and conduction heat from surrounding heat generating parts such as pans, coils, and ferrite do not reach the sensor directly, Since the surrounding gap acts as a heat insulating layer, the sensor can be prevented from becoming hot. Moreover, since it becomes a double cylinder shape, it becomes strong also in intensity | strength, the perpendicularity of a sensor and a light guide cylinder improves, and the detection accuracy of a sensor improves.

  A first invention includes a main body constituting an outer shell, a top plate mounted on an upper portion of the main body for placing a cooking container, and an alternating magnetic field provided below the top plate so as to face the top plate. A heating coil for inductively heating the cooking container, a coil base that holds the heating coil, an infrared sensor that is provided below the heating coil and detects infrared rays emitted from the cooking container, and a cooking container Infrared light from the cooking container is guided to the infrared sensor through an infrared incident area formed on the top plate so that infrared light emitted from the top plate can be transmitted, and is made of a resin that is fixed to or integrally formed with the coil base. A light guide unit; and a control unit configured to control an output of the heating coil based on an output signal of the infrared sensor, and the light guide unit projects downward. A light guide tube and a peripheral outer wall formed by providing a gap opened downward between the light guide tube and the outer wall, and facing the lower end opening of the light guide tube to the infrared sensor. By arranging an infrared condensing lens for condensing infrared rays, the surrounding gap is used as a heat insulation layer so that radiant heat and conduction heat from surrounding heat generating parts such as pans, coils, and ferrite do not reach the sensor directly. Since it acts, it can prevent that a sensor becomes high temperature. Moreover, since it becomes a double cylinder shape, it becomes strong also in intensity | strength, the perpendicularity of a sensor and a light guide pipe | tube improves, and the detection accuracy of a sensor can improve.

  According to a second aspect of the invention, in particular, in the first aspect of the invention, there is provided a sensor case that holds an infrared sensor so as to face the lower end opening and surrounds and stores the infrared sensor, and the sensor case faces the lower end opening. By having a case opening and bringing the periphery of the case opening into contact with the outer wall of the light guide unit, the light guided from the opening into the sensor case is only routed through the light guide tube and is not disturbed. It becomes stronger.

  According to a third aspect of the present invention, in particular, in the first or second aspect of the invention, the control means suppresses the output of the heating coil when the increase amount of the infrared output signal received by the sensor exceeds a predetermined value. Since there is a gap as a layer, the temperature in the light guide tube and in the vicinity of the infrared sensor is unlikely to change suddenly, and the operation of the sensor is easily 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 schematic cross-sectional view of an induction heating cooker C according to a first embodiment of the present invention. As shown in FIG. 1, the induction heating cooker C according to the present invention includes a main body 2 constituting an outline. And a top plate 4 attached to the upper part of the main body 2 and on which a cooking container P such as a pan is placed, and a substantially disc-shaped heating coil 6 provided below the top plate 4 and generating a high-frequency magnetic field. .

  The top plate 4 is formed in the shape of a plate made of an insulating material such as crystallized ceramic that transmits light, and the printed film 7a (on the back surface or the front surface thereof is displayed so that a circular region facing the upper surface of the heating coil 6 is displayed. A heating unit 5 on which a range for placing the cooking container P is displayed is formed (see FIG. 2). The print-out part 4c displaying the area of the heating part 5 is formed in a circle with a predetermined width line by a part where the print film 7a is not formed. A black light shielding layer 7b (see FIG. 6) having substantially zero transmittance is formed by printing. In addition, it is good also as a color different from the circumference | surroundings for the linear printed extraction part 4c. For example, as shown in FIG. 2, the circular printing portion 4d formed of the printing film 7a on the heating coil 6 and the printing portion 4e other than the heating coil 6 upper portion are made silver, and the printing punched portion 4c is transparent or translucent. A black or brown printed film may be formed. Alternatively, a plurality of radial slit portions 4f having a predetermined length may be provided on the outer side (lateral direction) of the outer periphery of the heating coil 6 to display the region of the heating unit 5. The slit portion 4f is formed to transmit light, or the periphery of the heating coil 6 of the top plate 4 is configured to transmit light, and an annular and linear light emitter (not shown) is provided below the slit portion 4f. The area of the heating unit 5 may be displayed by emitting light around the heating coil 6. The shapes of the printing unit 4d, the printing removal unit 4c, and the slit 4f are all for displaying the range of the heating unit 5, and one or more may be arbitrarily selected to display the range of the heating unit 5.

  An infrared sensor display window 4g (see FIG. 2) is formed in a part of the printing part 4d on the back surface of the top plate 4 that displays the heating part 5 at a printing part where the printing film 7d is not provided. Is almost rectangular. The infrared sensor display window 4g is an area facing the opening at the upper end of the first light guide tube 42a (see FIG. 6), which will be described later, within the range (inside), and the infrared sensor 10 is emitted from the cooking container P. It is formed so as to include an infrared incident area 4a which is an infrared incident area for receiving light and a light emitting area 4b which is a range in which light emitted from a light emitter 11 described later can be visually recognized. The infrared sensor display window 4g may be provided with a translucent printing film (not shown) such as white or brown to make it difficult to see the inside when viewed from the outside. Further, infrared rays may be transmitted through the entire infrared sensor display window 4g. Further, a light shielding layer 7b may be provided on the lower surface of the top plate 4 in a part of the infrared sensor display window 4g. For example, the transmission of light in the region of the infrared sensor display window 4g other than the infrared light incident region 4a and the light emitting region 4b of the light emitted from the light emitter 11 is disturbed to the infrared sensor 10 by providing the light shielding layer 7b. Intrusion can be suppressed.

  Within the region of the infrared sensor display window 4g, the characters “SENSOR” are displayed on the front side of the light emitting region 4b, which is the region where the light emission of the end of the second light guide 42b can be visually recognized, and the user can display the infrared sensor. It can be easily recognized that the window 4g is a window indicating a region for temperature measurement by the infrared sensor 10 and that the light emitting region 4b is a region to be covered with the cooking container P. Further, if the characters “SENSOR” are covered, the infrared incident area 4 a can be more reliably covered with the bottom surface of the cooking container P, and the accuracy of temperature measurement of the cooking container P can be increased by the infrared sensor 10.

  The heating coil 6 is placed on a coil base 8 formed of a heat-resistant resin, and a plurality of rod-shaped coil holders 9 are screwed to the coil base 8 at the outer peripheral portion of the heating coil 6, whereby the distal end portion of the coil holder 9. The inner periphery of the heating coil 6 is pressed and held, and the cooking container P is located below the coil base 8 on the near side from the center of the heating coil 6 (the same applies to the cooker side). An infrared sensor 10 that detects the temperature of the bottom and a light emitter 11 that emits light toward the top plate 4 are provided. The infrared sensor 10 and the light emitter 11 are installed on a substrate (printed wiring board) 12 and other electrical devices. It is electrically connected to the part.

  The infrared incident region 4a (see FIG. 6) of the top plate 4 is opposed to a portion different from the center of the heating coil 6 on the radial inside of the heating coil 6 with respect to the light emitting region 4b in the vicinity of the inner edge of the heating coil 6. The infrared sensor 10 is positioned directly below the infrared incident area 4a.

  The heating coil 6 has a split winding configuration of an inner coil and an outer coil, and the infrared incident region 4a and the light emitting region 4b are arranged inside the outer edge of the heating coil 6 and immediately below the inner coil and the outer coil. You can also.

  Further, a plate-like filter 14 for suppressing transmission of visible light is provided above the infrared sensor 10, and a side wall 16 for suppressing transmission of visible light is also provided around the infrared sensor 10. Yes. The filter 14 is attached on the substrate 12 so as to cover the infrared sensor 10 on the substrate 12 through the side wall 16 surrounding the infrared sensor 10, and the filter 14 positioned directly above the infrared sensor 10 includes There is a convex lens 18 for narrowing the field of view of the infrared sensor 10, that is, for increasing the amount of infrared light emitted from the cooking container P and not directly reflected from the inner surface of the first light guide tube 42a from the infrared incident region 4a. It is integrally formed.

  An amplifier (not shown) that amplifies the output signal from the infrared sensor 10 is also provided on the substrate 12, and the output signal from the infrared sensor 10 is amplified by the amplifier and connected to the connector 20. 22 and a temperature conversion means 24b for converting the amplified output signal of the infrared sensor 10 into the temperature of the cooking container, and is connected to the control means 24a. The control unit 24 a and the temperature conversion unit 24 b are configured on the control board 24. The temperature conversion means 24b may be configured on the substrate 12. Further, an operation panel 28 for operating the heating cooker C is provided in front of the control board 24.

  The substrate 12 on which the infrared sensor 10 and the light emitter 11 are placed is housed in a metal case 26 formed of a metal such as aluminum, nonmagnetic stainless steel, or iron plate, and the infrared sensor 10 receives light on the upper surface of the metal case 26. An opening 26c for allowing infrared light from the cooking container P to pass through and passing light emitted from the light emitter 11 is formed in a portion of the surface facing the light emitting surface of the light emitter 11. The lower end of the first light guide tube (first light guide portion) 42a is located below the upper surface of the metal case 26, and the infrared rays from the infrared incident region 4a are applied to the infrared sensor 10 so as to be close to the filter 14. Increasing the incident ratio. Further, the upper surface of the metal case 26 around the opening 26 c is in close contact with the lower surface of the light guide tube holding member (light guide portion holding member) 40 to which the metal case 26 is fixed, and the metal case 26 and the light guide tube holding member 40. Light is prevented from entering through the gaps between the two. The metal case 26 is assembled by fitting the upper metal case 26a and the lower metal case 26b. The metal case upper 26a and the metal case lower 26b are each formed by bending a metal plate. In addition, a fixed piece 26d is formed by bending a part of the upper metal case 26a outward. Further, the substrate 12 is screwed and fixed to a locking piece (not shown) in which a part of the upper metal case 26a is bent inward.

  Further, a part of the top plate 4 through which the light emitted from the light emitter 11 passes is a light emitting region 4b (see FIG. 6), which is a region where the user can visually recognize the light of the light emitter 11, and the light emitting region 4b is If it is located right above the light emitter 11 and the user perspectives from the near side, it will be located from right above the light emitter 11 due to the parallax, and the near side of the infrared light incident region 4a adjacent to the infrared light incident region 4a. Is provided. Note that a light diffusion layer may be printed on the light emitting region 4b of the top plate 4, and light from the light emitter 11 may be irradiated from below.

  When a heating operation is instructed by operating the operation panel 28, the output signal from the infrared sensor 10 is converted into the temperature of the cooking container P by the temperature conversion means 24b, but the infrared sensor is not provided with the temperature conversion means 24b. The ten output signals may be directly output to the control means 24a as temperature information. Based on the converted temperature or the output signal of the infrared sensor 10, the control means 24 a controls the inverter power supply 30 that supplies high-frequency power to the heating coil 6, and the temperature of the cooking container P is set to a predetermined temperature or a predetermined temperature or lower. Adjust.

  As shown in FIGS. 2 and 3, an aluminum plate having a thickness of about 0.5 to 1.5 mm is formed above the heating coil 6 placed and held on the coil base 8 in order from the top. The buoyancy reduction plate 32 for reducing the buoyancy acting on the cooking container P when the aluminum cooking container P is heated, the heat insulating sheet 34 which is a heat insulating material made of ceramic fiber with a thickness of about 2 mm, and a thickness of about A mica plate 36, which is a 0.5 mm electric insulating plate, is placed, and extends radially on the lower surface of the coil base 8 so as to concentrate the magnetic flux from the heating coil 6 to the back surface side in the vicinity of the heating coil 6. A plurality of ferrite cores 38 are attached at predetermined intervals. Most of these ferrite cores 38 except for a part (described later) are U-shaped in a side view, both ends thereof are bent upward, and the outer ends are located on the radially outer side of the heating coil 6, The inner end portion is located inside the heating coil 6 in the radial direction.

  Further, a resin-made light guide tube holding member 40 is attached to the lower surface of the coil base 8, and the infrared sensor described above is attached to the metal case fixing portion 40e (see FIG. 5) formed on the light guide tube holding member 40. The metal case 26 is attached to the light guide tube holding member 40 by screwing a fixing piece 26d of the metal case 26 in which the housing 10 is accommodated. At this time, the lower end of the light guide tube (light guide portion) 42 is inserted into the opening 26c, and the lower end of the outer wall 40f of the light guide tube 42, the lower surface of the annular portion 40a, and the upper surface of the metal case 26 are in close contact with each other. The light guided from the opening 26c into the metal case 26 is only through the light guide tube 42 as a path.

  Hereinafter, the configuration of the light guide tube holding member 40 will be described with reference to FIGS. 4 and 5.

  The light guide tube holding member 40 is formed in an annular shape with a predetermined width, and has an annular portion 40 a whose upper surface is in contact with the lower surface of the heating coil 6. A convex reinforcing rib 40h provided vertically downward is integrally formed at the width intermediate portion of the lower surface of the annular portion 40a. A light guide tube 42, a metal case fixing portion 40e, and a light guide tube outer wall 40f are integrally formed on the inner peripheral side of the front portion of the annular portion 40a. At the front part of the annular part 40a, in front of the light guide tube 42, a wiring locking part 40c is projected with a predetermined width in the outer radial direction, and a wiring locking piece 40d is integrally formed in an L-shaped cross section in the vicinity of the tip. Formed. On the lower surface of the annular portion 40a, a metal case fixing portion 40e is provided projecting downward in the vicinity of the light guide tube 42, and three light guide tube holding member fixing portions 40g are dispersedly provided. A first thermistor holding member 44 is integrally formed in the vertical direction at the rear portion of the annular portion 40a. In addition, the lower part of the second thermistor holding member 51 is located at the center of the annular part 40a, that is, between the light guide tube 42 and the first thermistor holding member 44, at a position directly below the center of the heating coil 6. A covering second thermistor cover 46 is integrally formed with a connecting member 48 for connecting the second thermistor cover 46 and the annular portion 40a. The first and second thermistor holding members 44 and 46 accommodate first and second thermistors 50 and 52, respectively, together with coil springs 53 and 55 formed in a solenoid coil shape (see FIG. 1). Similar to the infrared sensor 10, the second thermistors 50 and 52 are connected to the control means 24a through lead wires (not shown) connected to connectors (not shown).

  The first and second thermistors 50 and 52 are temperature detecting means for detecting the temperature of the cooking container P by heat conduction, and the first and second thermistor holding members 44 and 51 are accommodated in the first and second thermistor holding members 44 and 51, respectively. The two thermistors 50 and 52 are urged toward the top plate 4 by coil springs 53 and 55. The second thermistor holding member 51 is integrally molded and held with resin together with the coil base 8 and the connecting member 49, and the lower portion is covered with the second thermistor cover 46, and the cooling air is supplied to the second thermistor holding member 51. The second thermistor 52 is prevented from being cooled by entering the second thermistor holding member 51 from the hole for locking the locking portion of the thermistor 52 on the lower surface of the second thermistor 52. In addition, since the infrared sensor 10 is more excellent in transient temperature responsiveness than the thermistors 50 and 52, the bottom surface of the cooking container P is rapidly heated in the case of cooking with a small amount of oil such as fried food cooking. Even when it rises, the temperature of the bottom surface of the cooking container P can be measured with high sensitivity according to the output of the infrared sensor 10, and the output of the heating coil 6 is quickly reduced immediately before oil ignition or the like occurs, as well as vegetables, etc. When the food to be cooked is charged and the temperature of the cooking container P is lowered, the output is controlled to be quickly recovered. However, if the temperature of the cooking container P cannot be detected by the infrared sensor 10 because the cooking container P is not placed above the infrared sensor 10 or if the infrared sensor 10 fails, the heating coil 6 is used as a backup. The thermistor 50 is provided at a position behind the center, and the thermistor 52 in the center of the heating coil 6 is provided for temperature adjustment when the oil temperature is automatically set during frying.

  A convex rib 40b is integrally formed on the inner edge of the annular portion 40a of the light guide tube holding member 40, and this rib 40b is bonded and held to the back surface of the coil base 8 by an adhesive. The light guide tube holding member fixing portions 40g, which are inserted along the inner end surfaces of the plurality of ferrite cores 38 and are provided on the annular portion 40a of the light guide tube holding member 40, are screwed to the coil base 8. Thus, the bottom surface and the side surface of the inner end portion of the ferrite core 38 are held and regulated by the light guide tube holding member 40. Therefore, the light guide tube holding member 40 also functions as a mechanical holding member for the ferrite core.

  Since the light guide tube 42 and the first thermistor holding member 44 are partly located outside the rib 40 b, the inside of the ferrite core 38 corresponding to the light guide tube 42 and the first thermistor holding member 44. The end portion is cut out so as not to interfere with the light guide tube 42 and the first thermistor holding member 44, and the ferrite core 38 with the inner end portion cut out is shorter than the other ferrite cores 38. It has a letter shape. As shown in FIG. 3, at least a part of the buoyancy reduction plate 32, the heat insulating sheet 34, and the mica plate 36 positioned above the light guide tube 42 and the first thermistor holding member 44 is from the cooking container P to the light guide tube. The first and second thermistors 50 and 52 are notched so as to pass through and contact the back surface of the top plate 4 so as not to block infrared rays incident on the infrared sensor 10 through the upper opening of 42.

  In addition, the light guide tube 42 has an elliptical cross-sectional outer shape, and the inside thereof is divided into two parts. The light guide tube 42 is a second for guiding infrared rays radiated from the cooking container P toward the center of the heating coil 6 to the infrared sensor 10. 1 light guide tube 42a is formed, located near the outer edge side of the heating coil 6 with respect to the first light guide tube 42a, and further emitted from the light emitter 11 to the front side of the center of the heating coil 6. A second light guide tube (second light guide portion) 42 b for guiding light toward the top plate 4 is formed. Therefore, the metal case 26 containing the infrared sensor 10 and the light emitter 11 is arranged so that the infrared sensor 10 and the light emitter 11 face the lower end openings of the first light guide tube 42a and the second light guide tube 42b, respectively. The light guide tube holding member 40 is screwed.

  A horseshoe-shaped rib 42c extending upward is formed on the upper end of the light guide tube 42 along the outer periphery of the upper end of the light guide tube 42, and a stepped portion 42d having a predetermined width is disposed outside thereof. A light guide 56 for accommodating the light emitted from the light emitter 11 efficiently in the vicinity of the top plate 4 so that the light is easily visible is accommodated inside the light guide tube 42b. When the mica plate 36 shown in FIG. 3 is fixed on the heating coil 6, a rib 42c is fitted into a hole 36a provided in the mica plate 36, and the hole 36a is formed on the step portion 42d as shown in FIG. The peripheral edge is placed. Similarly, a substantially annular rib 51a extending upward and an outer stepped portion 51b are formed at the upper end of the hemispherical container-like second thermistor holding member 51, and the rib 51a is fitted into the hole 36b of the mica plate 36. Then, the edge around the hole 36b is placed on the stepped portion 51b. Cooling air A blown by a cooling fan (not shown) is sent from below the center of the heating coil 6 as shown in FIG. 6, hits the lower surface of the mica plate 36, and the upper surface of the heating coil 6 along the lower surface of the mica plate 36. Flows radially through the gap. Since the cooling air A passes through the lower surface of the mica plate 36 and the upper surface of the heating coil 6 without directly touching the heat insulating material 34 and the top plate 4, the heating coil 6 can be efficiently cooled. Further, since the mica plate 36 is placed on the upper end surface of the light guide tube 42 including the stepped portion 42d, the path through which the high-temperature cooling air A is sent into the first light guide tube 42a is blocked. Therefore, it is possible to prevent the temperature of the infrared sensor 10 from being raised to an allowable temperature or higher by the cooling air A being blown around the infrared sensor 10.

  As shown in FIGS. 5 and 6, the light guide 56 is formed in a columnar shape, and a lower portion of the light guide 56 is inserted into a pair of notches 42f formed at the lower end of the second light guide tube 42b. A pair of locking pieces 56a for locking the light body 56 to the second light guide tube 42b are integrally formed. The light guide 56 is inserted into the second light guide tube 42b from below before the metal case 26 is attached to the light guide tube holding member 40.

  Further, as shown in FIGS. 5, 6, and 7, the light guide 42 has a light guide tube 42 a and an outer wall 40 f that are formed to protrude downward, and between the light guide tube 42 a and the outer wall 40 f. A heat insulating layer having a gap 42g opened downward is provided, and the infrared condensing lens 18 is disposed so as to face the lower end opening of the light guide tube 42a.

  About the induction heating cooking appliance C comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the food is put in the cooking container P and cooked by the induction heating cooker C according to the present invention, when the power switch (not shown) of the induction heating cooker C is turned on, the light emitter 11 emits light and the emitted light is emitted. In the vicinity of the infrared incident area 4a of the top plate 4 guided by the light guide 56 (the outer side in the radial direction of the heating coil 6 with respect to the infrared incident area 4a on the near side of the center of the heating coil 6, in this embodiment, heating is performed. The light emitting region 4b is irradiated on the line passing through the center of the coil 6 and perpendicular to the front surface of the main body 2. Therefore, the user can visually recognize the light emission of the light emitting region 4b provided on the radially outer side of the heating coil 6 with respect to the infrared incident region 4a, and the cooking container P is placed on the top plate 4 so as to close the light emitting region 4b. If placed, the infrared sensor 10 can reliably receive the infrared rays emitted from the bottom surface of the cooking container P.

  When the operation panel 28 is operated to start heating, the control means 24 a supplies a high frequency current to the heating coil 6 via the inverter power supply 30. When a high-frequency current is supplied to the heating coil 6, the heating coil 6 generates an alternating magnetic field, and the temperature of the cooking vessel P rises due to induction heating. When the temperature of the cooking vessel P rises, the cooking vessel P generally emits infrared energy proportional to a quadruple of its absolute temperature, as shown by Stefan-Boltzmann law. Infrared radiation radiated from the cooking container P passes through the infrared incident region 4a and the inside of the first light guide tube 42a, passes through the filter 14 provided to cover the infrared sensor 10 and removes unnecessary light. The infrared sensor 10 is reached.

  Further, when the temperature of the cooking container P rises, the output signal of the infrared sensor 10 receiving the infrared energy increases, and as described above, this output signal is amplified by the amplifier and input to the temperature conversion means 24b to convert the temperature. The output signal of the infrared sensor 10 is converted into the temperature of the cooking container P by means 24b. When the converted temperature of the cooking container P exceeds a predetermined temperature set in advance, the control unit 24a stops the supply of the high-frequency current output from the inverter power supply 30 to the heating coil 6 or reduces the high-frequency current. Adjust.

  The infrared incident region 4a is formed so as to face the opening surface at the upper end of the first light guide tube 42a provided to be located inside the outer edge portion of the heating coil 6 and at a position different from the center of the heating coil 6. This is a portion of the top plate 4. Since the emitted light of the light emitter 11 guided by the second light guide tube 42b is emitted from the infrared incident region 4a in the radial direction outside the heating coil 6 so as to be visible, the temperature is higher than above the central portion of the heating coil 6. The infrared rays emitted from the portion of the cooking container P can be made incident on the infrared sensor 10 and the center of the cooking container P is brought as close as possible to the center of the heating coil 6 so that the light emitting region 4b of the cooking container P Can be covered with the bottom. Thereby, the magnetic coupling between the heating coil 6 and the heating container P can be increased, that is, the heating efficiency can be increased, and the bottom surface of the cooking container P can be positioned on the infrared incident region 4a. Therefore, it becomes possible to reliably control the temperature of the cooking container P by the infrared sensor 10 while increasing the heating efficiency, thereby suppressing abnormal heat generation of the cooking container P and improving safety, and efficient cooking at high temperatures. Can be done well and improves usability.

  Further, the top plate 4 includes an infrared sensor display window 4g that displays an area surrounding at least a part of the infrared incident area 4a, so that light emitted from the light emitter 11 can be visually recognized in the area surrounded by the infrared sensor display window 4g. Therefore, the user indicates the meaning of the light emission in the light emitting area 4b of the light emitter 11, the infrared incident area 4a that does not emit light, and the presence of the infrared sensor 10, and the light emitting portion 4b by the light of the light emitter 11 in the infrared sensor display window 4g. And the infrared incident region 4a can be easily recognized.

  Further, since the infrared incident area 4a is positioned on the front side of the center of the heating coil 6, the light of the light emitter 11 that emits light on the outer edge side of the heating coil 6 near the infrared incident area 4a is above the cooking container. When P is not located, it is difficult to hide from the side wall of the cooking container P when viewed from the cook side, and the cook can more easily visually recognize the light emitting portion.

  In addition, since the infrared incident region 4a is positioned on a line that passes through the center of the heating coil 6 and is orthogonal to the front surface of the main body, the light of the light emitter 11 that emits light on the outer edge side of the heating coil 6 near the infrared incident region 4a When the cooking container P is not located above the cooking container P, the cooking container P is most difficult to hide on the side wall of the cooking container P, and the cooking person can visually recognize the light-emitting part most easily. be able to.

  Further, when the first thermistor 50 serving as the first temperature detecting means for detecting the back surface temperature of the top plate 4 by heat conduction is provided on the opposite side of the infrared incident area 4a with respect to the center of the heating coil 6, the thermal coil 6 is provided. In addition to the infrared sensor 10 that measures a temperature higher than the temperature of the cooking container P at the upper center, the temperature of the cooking container P that is higher than the temperature at the upper center of the heating coil 6 is measured by the first thermistor 50. Even when the infrared sensor 10 fails or when the cooking container P does not properly cover the infrared incident area 4a, the first thermistor 50 does not detect the temperature of the cooking container P. Since the temperature of P can be detected, safety and usability are further improved.

  Moreover, when the 2nd thermistor 52 which is a 2nd temperature detection means which detects the back surface temperature of the top plate 4 by heat conduction is provided in the approximate center of the heating coil 6, it is located above the center of the heating coil 6 of the cooking container P. In addition to the infrared sensor 10 for measuring the portion of the cooking container P that is hotter than the bottom surface portion to be cooked, the cooking container is most stable with respect to the deviation of the center position of the cooking container from the center of the heating coil at the temperature of the cooking container P. Since the bottom surface temperature of P is measured by the second thermistor 52, when ambient light is incident on the infrared sensor 10, the temperature measurement circuit using the infrared sensor 10 such as the infrared sensor 10 or the temperature conversion means 24b fails. Even when the temperature of the cooking container P cannot be detected by the infrared sensor 10, such as when the cooking container P does not cover the infrared incident region 4a, the second thermistor Because it detects the temperature of the cooking container P 2, it is possible to accurately control the steady-state temperature, such as temperatures of the oil during frying, usability is further improved. By further providing the first thermistor 50 on the opposite side of the infrared sensor 10 with respect to the center of the heating coil 6, the reliability when disturbance light is incident on the infrared sensor or when the position of the cooking container is displaced is improved. be able to.

  Further, since the first light guide tube 42a and the second light guide tube 42b are integrally formed of resin, there is no relative displacement between the first light guide tube 42a and the second light guide tube 42b. Simple and easy to manufacture.

  In addition, a coil base 8 made of resin for holding the heating coil 6 and a light guide tube holding member 40 formed integrally with the first light guide tube 42a and the second light guide tube 42b are further provided. Since the light guide tube holding member 40 is fixed to the coil base 8, it is easy to regulate the positional deviation between the heating coil 6 and the light guide tube 42, and the first light guide tube is incorporated into the main body at the same time. 42a and the 2nd light guide cylinder 42b can be integrated in a main body, and the measurement structure of the bottom face temperature of the cooking container P provided with the light emission area | region 4b which shows the measurement by the infrared sensor 10, and its position is easily realizable. The first light guide tube 42a or the second light guide tube 42b may be integrally molded with the coil base 8 and resin and fixed to the coil base 8.

  Further, since the light guide 56 is inserted into the second light guide tube 42b, the light from the light emitter 11 can be efficiently guided to the vicinity of the infrared incident region 4a, and the assembly is easy.

  Further, since the end portions of the plurality of ferrite cores 38 provided below the heating coil 6 are held by the light guide tube holding member 40, the ferrite core 38 is mechanically held and at the same time the light guide tube holding member 40 is heated. 6 and the structure is simple.

  In addition, since the gap 42g is provided, the peripheral gap 42g acts as a heat insulating layer so that the radiant heat and conduction heat from the surrounding heat generating parts such as pans, coils, and ferrite do not reach the infrared sensor 10 directly. It can prevent that 10 becomes high temperature. Note that the gap 42g does not necessarily have to be provided on the entire circumference, and may be provided only in a necessary portion where heat insulation is desired. Or about the location cooled with the cold wind, it is not necessary to provide the clearance gap 42g and to insulate.

  Moreover, since it becomes a double cylinder shape, it becomes strong also in strength, and the perpendicularity with the infrared sensor 10 is easily obtained, and the detection accuracy of the sensor is increased.

  Further, the lower end of the light guide tube (light guide portion) 42 is inserted into the opening 26c, and the lower end of the outer wall 40f of the light guide tube 42, the lower surface of the annular portion 40a, and the upper surface of the metal case 26 are in close contact with each other, By using the outer wall 40f and the annular portion 40a in which the gap 42c is formed, the light guided into the metal case 26 from the opening 26c is only routed through the light guide tube 42, and is strong against disturbance light. Become.

  In addition, the control means suppresses the output of the heating coil when the increase amount of the infrared output signal received by the sensor exceeds a predetermined value. In such a case, there is a gap 42g serving as a heat insulating layer. Therefore, the temperature in the light guide tube 42a and in the vicinity of the infrared sensor 10 is unlikely to change suddenly, and the operation of the sensor is easily stabilized.

  As described above, the induction heating cooker C according to the present invention arranges the incident region 4a to the infrared sensor 10 for infrared rays radiated from the cooking container P such as a pan at different positions from the center of the heating coil 6. The temperature of the high temperature part of the cooking container P can be measured by the infrared sensor 10 to control the temperature of the cooking container P with high sensitivity, and the light guide part is made of resin and protrudes downward. 1 light guide tube is provided, a gap opened downward is provided between the light guide tube and an outer wall around the light guide tube, and an infrared condensing lens is disposed facing the lower end opening surface of the light guide tube As a result, the surrounding gap acts as a heat insulation layer so that radiant heat and conduction heat from surrounding heat generating parts such as pans, coils, and ferrite do not reach the sensor directly, so that the sensor can be prevented from becoming hot. . In addition, since it has a double cylindrical shape, the strength is increased, the verticality of the sensor and the light guide tube is improved, the sensor accuracy is improved, and it is useful as an induction heating cooker for home use or business use. .

Schematic sectional view of induction heating cooker in Embodiment 1 of the present invention The fragmentary top view of the top plate provided in the induction heating cooking appliance in Embodiment 1 of this invention The principal part disassembled perspective view of the induction heating cooking appliance in Embodiment 1 of this invention The disassembled perspective view of the light guide cylinder holding member provided in the induction heating cooking appliance in Embodiment 1 of this invention The disassembled perspective view at the time of seeing the light guide cylinder holding member provided in the induction heating cooking appliance in Embodiment 1 of this invention from the bottom The elements on larger scale of the infrared sensor vicinity provided in the induction heating cooking appliance in Embodiment 1 of this invention The fragmentary sectional view of the infrared sensor vicinity provided in the induction heating cooking appliance in Embodiment 1 of this invention

Explanation of symbols

2 Main body 4 Top plate 4a Infrared incident area 4b Light emitting area 4c Printing out part 4d Printing part 4f Slit part 4g Infrared sensor display window 4e Printing part 5 Heating part 6 Heating coil 7a Printed film 7b Light shielding layer 8 Coil base 9 Coil holder 10 Infrared Sensor 11 Light emitter 12 Substrate 14 Filter 16 Side wall 18 Lens 20 Connector 22 Lead wire 24 Control board 24a Control means 24b Temperature conversion means 26 Metal case 26a On metal case 26b Under metal case 26c Opening 28 Operation panel 30 Inverter power supply 32 Decrease buoyancy Plate 34 Heat insulation sheet 36 Mica plate 36a Hole 36b Hole 38 Ferrite core 40 Light guide tube holding member (light guide holding member)
40a annular portion 40b rib 40c wiring locking portion 40d wiring locking piece 40e metal case fixing portion 40f light guide tube lower outer wall 40g light guide tube holding member fixing portion 40h reinforcing rib 42 light guide tube (light guide portion)
42a 1st light guide cylinder (1st light guide part)
42b 2nd light guide cylinder (2nd light guide part)
42c rib 42d step part 42f notch 42g gap 44 first thermistor holding member 46 second thermistor cover 48 connecting member 50 first thermistor 51 second thermistor holding member 51a rib 51b step part 52 second thermistor 56 light guide Body 56a Locking piece C Induction heating cooker P Cooking container

Claims (3)

A main body constituting the outer shell, a top plate attached to the upper portion of the main body for placing the cooking container, and a cooking container that generates an alternating magnetic field and is provided below the top plate so as to face the top plate. A heating coil for induction heating, a coil base that holds the heating coil, an infrared sensor that is provided below the heating coil and detects infrared rays emitted from the cooking vessel, and infrared rays emitted from the cooking vessel Inducting infrared rays from a cooking container to the infrared sensor through an infrared incident area formed on the top plate so that it can pass through, and a resin light guide portion fixed to or integrally formed with the coil base, Control means for controlling the output of the heating coil based on the output signal of the infrared sensor, and the light guide portion is formed to project downward. A light tube and a surrounding outer wall are provided, a gap opened downward is provided between the light guide tube and the outer wall, and the infrared light is condensed on the infrared sensor facing the lower end opening of the light guide tube. An induction heating cooker characterized in that an infrared condenser lens is disposed. An infrared sensor is held so as to face the lower end opening, and includes a sensor case that surrounds and accommodates the infrared sensor, the sensor case has a case opening facing the lower end opening, and a light guide portion around the case opening The induction heating cooker of Claim 1 made to contact | abut to the outer wall of. The induction heating cooker according to claim 1 or 2, wherein the control means suppresses the output of the heating coil when the amount of increase in the infrared output signal received by the sensor exceeds a predetermined value.

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