Heating Regulator

Abstract

To suppress deformation of a coil of a heating cooker having a plurality of coils.SOLUTION: A heating cooker comprises: a housing part 40 with a bottom that houses a pot; a non-cylindrical shape coil 55 that is arranged to a peripheral direction as a center of a shaft line of the housing part 40 on an outer surface side positioned at the side opposite to the pot in the housing part 40, and guides and heats the pot; and a coil depressing part 67 that is adjacent from an outer surface side to an end part of a peripheral direction of the coil 55. Deformation easily occurred in the end part of the peripheral direction of the outer side coil 55 is suppressed.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a cooking device. [Background technology]

[0002] Patent Document 1 discloses a cooking device in which a plurality of coils are arranged at intervals in the circumferential direction of a bottomed cylindrical container that houses a pot. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-129843 Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, the gap between adjacent coils around the periphery of the pot is reduced to ensure a heating area using multiple coils. The applicant of this application has discovered that in such cases, with repeated use, deformation may occur in the end of the coil around the periphery of the pot, moving it away from the pot. This deformation may cause the pot to be insufficiently heated. Patent Document 1 does not disclose how insufficient heating of the pot may result from this warping.

[0005] An object of the present invention is to suppress deformation of coils in a cooking device having a plurality of coils. [Means for solving the problem]

[0006] One aspect of the present invention provides a cooking device comprising a cylindrical storage section with a bottom for storing a pot, a non-circular coil arranged circumferentially around the axis of the storage section on the outer surface of the storage section opposite the pot, for induction heating the pot, and a coil holder adjacent to the outer surface side of the circumferential end of the coil.

[0007] According to this aspect, the coil retainer can suppress deformation that is likely to occur, particularly at the circumferential ends of the coil, due to heating caused by current flow. For example, if a resin such as varnish applied to the coil to maintain its curved state along the shape of the housing softens due to heating, and the circumferential ends of the coil deform in a direction away from the curved shape of the housing, the ends of the coil come into contact with the retainer. This allows the coil retainer to suppress deformation of the coil.

[0008] The coil may have a major axis in a circumferential direction of the pot and a minor axis in a radial direction of the pot.

[0009] According to this configuration, the radius of curvature of the coil in the circumferential direction is smaller than the radius of curvature of the minor axis in the radial direction of the coil. In other words, the curvature of the coil in the circumferential direction changes more rapidly than in the radial direction. With repeated use (repeatedly switching between heated and unheated states), distortion is likely to occur at the circumferential end of the coil where the curvature changes rapidly, so the effect of the retainer in suppressing coil deformation is more pronounced.

[0010] The width of the coil in the circumferential direction of the pot may be greater than the width of the coil in the radial direction of the pot.

[0011] According to this configuration, if the width of the coil in the circumferential direction is to be made larger than the width of the coil in the radial direction, the thickness of the coil in the circumferential direction must be made thinner than the thickness of the coil in the radial direction and it must be extended in the circumferential direction.Since the coil is more likely to deform when it is thinner, the effect of the holding portion in suppressing deformation of the coil is more pronounced.

[0012] The coil pressing portion may have a first pressing portion adjacent to the outer periphery side of the coil and a second pressing portion adjacent to the inner periphery side of the coil.

[0013] According to this configuration, by providing a gap between the first pressing portion and the second pressing portion, deformation of the coil can be suppressed without impeding the heat dissipation properties of the coil.

[0014] a ferrite holder for holding a ferrite core disposed outside the coil; The coil pressing portion may be provided on the ferrite holder.

[0015] According to this configuration, the coil pressing portion is provided on the ferrite holder, so no dedicated part is required for providing the coil pressing portion, and an increase in the number of parts can be suppressed.

[0016] A sensor that contacts the pot is disposed in the storage section, The coil may be located in proximity to the sensor.

[0017] According to this configuration, the temperature of the coil can be detected by the sensor with higher accuracy than when the coil is provided at a distance from the sensor.

[0018] The gap between the coil and the sensor may be set to be equal to or greater than 3 mm and equal to or less than 20 mm.

[0019] According to this configuration, the gap between the coil and the sensor is appropriately set. If it is less than 3 mm, the assembly of the coil is hindered, and if it exceeds 20 mm, the accuracy of temperature detection by the sensor decreases. [Effects of the Invention]

[0020] According to the present invention, deformation of the coils in a cooking device having a plurality of coils can be suppressed. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a rice cooker (heat cooking device) according to an embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view of the rice cooker with the lid not shown. [Figure 3] FIG. [Figure 4] FIG. 4 is a perspective view of a protective frame with a coil assembled thereto. [Figure 5] FIG. 2 is a view of the inner coil as seen from the direction in which the axis of the inner coil extends. [Figure 6] FIG. 2 is a view of the outer coil as seen from the direction in which the axis of the outer coil extends. [Figure 7] FIG. 2 is a schematic diagram showing a cross section of the outer coil along its long axis. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 10 is a bottom view of the ferrite holder attached to the protective frame. [Figure 10] FIG. [Figure 11] FIG. 10 is a perspective view of the ferrite holder attached to the protective frame. [Figure 12] FIG. 10 is a perspective view of the ferrite holder as viewed from a direction in which the outer coil faces forward. [Figure 13] FIG. 4 is a perspective view of the ferrite holder as viewed from a direction in which the coil pressing portion faces forward. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] Fig. 1 is a perspective view from above of a rice cooker (heat cooking appliance) 1 according to one embodiment of the present invention, with the lid 30 open and the pot 10 removed. Fig. 2 is a cross-sectional view of the rice cooker 1. Fig. 3 is an exploded perspective view of the rice cooker 1.

[0024] As shown in FIG. 1, the rice cooker 1 comprises a rice cooker body 20 that detachably houses a bottomed cylindrical pot 10 for heating rice, and a lid 30 that is rotatably disposed relative to the rice cooker body 20.

[0025] Referring to Figures 1 and 2, pot 10 is made of a magnetic material and is induction heated by a coil 50 disposed within rice cooker body 20. Pot 10 has bottom 10a, side 10b, and curved portion 10c. Bottom 10a is circular and extends substantially flat in the left-right direction. Side 10b is substantially cylindrical and extends outward in the up-down direction. Curved portion 10c connects bottom 10a and side 10b. Curved portion 10c has a curved surface shape that connects the radially outer end of bottom 10a to the lower end of side 10b.

[0026] The lid body 30 is rotatably attached to the connecting part 24 of the rice cooker body 20, and closes the opening 20a of the rice cooker body 20 when closed on the rice cooker body 20.

[0027] Referring to Figure 3, the lid body 30 has, at its front side, an operation unit 31 for operating the rice cooker 1 and a display unit 32 for displaying the operation status and operating status, and, at its rear side, a steam exhaust port 33 which is the outlet of the exhaust passage.

[0028] The operation unit 31 has multiple operation buttons 31a and an opening button 31b. The operation buttons 31a are buttons for switching the operating state of the rice cooker 1, such as a button to start cooking rice, a button to cancel operation, and a power button. The opening button 31b is a button for opening the lid 30, which is kept closed by a locking mechanism.

[0029] Referring to FIG. 1, an inner lid (not shown) is attached to the inside of lid body 30 to close top opening 10d of pot 10 in a closed state. The inner lid has a sealing member (not shown) that fits tightly against the inner periphery of top opening 10d of pot 10 to close top opening 10d. The inner lid is detachably attached to lid body 30.

[0030] As shown in Figures 2 and 3, the rice cooker body 20 has a casing 21, a housing (protective frame) 40, a coil 50, a ferrite 91 (see Figure 9), a ferrite holder 60, a reflector 70, a power supply board 26, an IH board 27, and a cooling fan 28.

[0031] 1, the casing 21 includes a casing body 22, a shoulder 23, and a connecting portion 24. The casing body 22 is box-shaped and includes a bottom surface 22a, a peripheral wall portion 22b surrounding the bottom surface 22a, and an opening 22c formed at the upper end of the peripheral wall portion 22b.

[0032] The shoulder body 23 is attached from above so as to cover the opening 22c of the casing body 22. An engagement hole 23a is provided on the front side of the shoulder body 23 to engage with a locking claw 34 provided on the front part of the lid body 30. The connection part 24 is provided on the rear side of the shoulder body 23 and is a hinge part for rotatably attaching the lid body 30.

[0033] As shown in Figure 2, the protective frame 40 is positioned within the casing body 22, below the shoulder body 23. The pot 10 is placed within the protective frame 40. The inner body 25 is positioned above the protective frame 40 and below the shoulder body 23. The inner body 25 is cylindrical and has a diameter slightly larger than that of the pot 10, and is made of a metal material. When the pot 10 is placed within the protective frame (storage section) 40, the axis A of the pot 10 and the axis B of the protective frame 40 coincide with each other.

[0034] FIG. 4 is a perspective view of the protective frame 40 to which the coil is attached. FIG. 4 is shown upside down compared to FIGS. 1 to 3. In FIG. 4, the shape of the coil 50 is shown schematically for clarity and simplicity of illustration. In reality, the coil 50 has a spiral shape formed by winding a wire. The coil 50 has multiple layers of wire laminated in the radial direction. In other words, the coil 50 has multiple layers of wire laminated from the outer circumferential surface of the protective frame 40 outward.

[0035] Protective frame 40 includes a cylindrical pot accommodating portion 41 with a bottom that accommodates pot 10, and a board support portion 42 that supports power supply board 26. Protective frame 40 is made of a non-conductive material (for example, a synthetic resin material).

[0036] 2 and 4, pot accommodating portion 41 has bottom portion 41a, side portion 41b, and curved portion 41c. Bottom portion 41a is located outside bottom portion 10a of pot 10 and has a circular shape that extends generally flat in the left-right direction. Side portion 41b is located outside side portion 10b of pot 10 and has a generally cylindrical shape that extends up-down and outward. Curved portion 41c is located outside curved portion 10c of pot 10 and has a curved surface shape that connects bottom portion 41a and side portion 41b.

[0037] Bottom portion 41a and curved portion 41c are provided with threaded holes and cylindrical bosses 41d extending vertically. Side portion 41b is provided with cylindrical penetration portion 41e (sensor mounting portion) through which a temperature sensor (not shown) is inserted. The sensor mounted in mounting portion 41e penetrates pot housing portion 41 and abuts against pot 10.

[0038] A plurality of brackets 44 are provided on the upper peripheral edge of the protective frame 40. The brackets 44 are used to be screwed to the shoulder body 23. A central support part 45 is provided in the center of the bottom surface of the protective frame 40. The central support part 45 is generally cylindrical and protrudes downward, and is inserted into the central part 61 of the ferrite holder 60 to position the ferrite holder 60 (see FIG. 9).

[0039] 4, coil 50, which is non-circular in plan view (specifically, doughnut-shaped), is disposed on the outer peripheral surface of pot accommodating section 41. Coil 50 includes inner coil 51 and outer coil 55, which have different shapes, and generates eddy currents when a high-frequency current is passed through them, thereby inductively heating pot 10.

[0040] A plurality of the inner coils 51 and the outer coils 55 are arranged side by side around the axis A. In this embodiment, three of each of the inner coils 51 and the outer coils 55 are arranged. The inner coils 51 adjacent to each other in the circumferential direction are arranged at intervals, and the outer coils 55 adjacent to each other in the circumferential direction are arranged at intervals. The inner coils 51 and the outer coils 55 adjacent to each other in the radial direction are arranged at intervals.

[0041] Inner coil 51 is arranged on the outer surface of pot accommodating portion 41, from bottom 41a to curved portion 41c, so as to induction heat bottom 10a and curved portion 10c of pot 10. In other words, inner coil 51 is arranged radially inward (toward axis A) of side portion 41b, in a region spanning from bottom 41a to curved portion 41c of pot accommodating portion 41.

[0042] FIG. 5 is a view of the inner coil 51 as seen from the direction in which the axis of the inner coil 51 extends.

[0043] 4 and 5, inner coil 51 is non-circular, with a major axis a1 extending radially of pot 10 and a minor axis a2 extending circumferentially of pot 10. In this embodiment, inner coil 51 has minor axis a2 positioned closer to axis A than the center of major axis a1.

[0044] As shown in Figure 5, the inner coil 51 comprises an inner portion 52 arranged on the axis A side of the pot 10, and an outer portion 53 extending from the inner portion 52 radially outward from the pot 10. The inner portion 52 and the outer portion 53 are connected via a pair of curved portions 54 curved at a predetermined curvature. The inner portion 52, the outer portion 53, and the curved portions 54 are all formed in an arc shape with a predetermined curvature, but are not limited to a strict arc shape, as long as they are substantially arc-shaped from one end to the other.

[0045] The inner portion 52 extends generally in the circumferential direction of the pot 10. The inner portion 52 is curved at a predetermined radius of curvature R1. The outer portion 53 extends from the inner portion 52 radially outward of the pot 10 and is curved at a predetermined radius of curvature R2 that is smaller than the radius of curvature R1. The curved portion 54 connects the inner portion 52 and the outer portion 53. The curved portion 54 is curved at a predetermined radius of curvature R3 that is larger than the radius of curvature R1.

[0046] FIG. 6 is a view of the outer coil 55 as seen from the direction in which the axis of the outer coil 55 extends.

[0047] 4 and 6, outer coil 55 is positioned radially outward of inner coil 51 with respect to axis A so as to induction heat all but the central portion of bottom 41a of pot 10. Outer coil 55 is positioned across from side portion 41b to curved portion 41c of pot accommodating portion 41. Outer coil 55 as a whole curves along the radial and circumferential curves of pot accommodating portion 41.

[0048] As shown in Figure 6, outer coil 55 is non-circular, with a major axis a3 extending circumferentially around pot 10 and a minor axis a4 extending radially around pot 10. In this embodiment, outer coil 55 has a generally elliptical shape and is flattened to a greater extent in the radial direction than inner coil 51.

[0049] The ratio of the major axis a3 to the minor axis a4 of the inner circumferential portion 55a of the outer coil 55 is set to 2.5 to 3, preferably 2.7 to 2.9. The ratio of the major axis a3 to the minor axis a4 of the outer circumferential portion 55b of the outer coil 55 is set to 2 to 2.5, preferably 2.2 to 2.4.

[0050] The shape of outer coil 55, like inner coil 51, depends on the shape of the jig used to form outer coil 55. The jig has a shape that matches the shape of pot housing 41. The coil wire wound and bundled around the jig is hardened by filling it with an insulating layer such as varnish, and the desired shape is maintained.

[0051] The outer coil 55 comprises an inner portion 56 arranged on the axis A side of the pot 10, and an outer portion 57 extending from the inner portion 56 radially outward of the pot 10. The inner portion 56 and the outer portion 57 are connected via a pair of curved portions 58 curved at a predetermined curvature. The inner portion 56, the outer portion 57, and the curved portions 58 are all formed in an arc shape with a predetermined curvature, but are not limited to a strict arc shape, as long as they are substantially arc-shaped from one end to the other.

[0052] The inner portion 56 and the outer portion 57 extend circumferentially around the pot 10 as a whole. The inner portion 56 and the outer portion 57 are curved at a predetermined radius of curvature (first radius of curvature) R4. The curved portion 58 connects the inner portion 56 and the outer portion 57. The curved portion 58 is curved at a predetermined radius of curvature (second radius of curvature) R5 that is smaller than the radius of curvature R4. The radius of curvature R5 of the curved portion 58 is set smaller than the radius of curvature R4 of the inner portion 56 and the outer portion 57.

[0053] The ratio of the radius of curvature R5 of the curved portion 58 to the radius of curvature R4 of the inner portion 56 and the outer portion 57 is set to be 1.5% or more and 3% or less, and more preferably 2% or more and 2.5% or less. In other words, the curvature of the curved portion 58 changes more rapidly than that of the inner portion 56 and the outer portion 57.

[0054] If the ratio of the radius of curvature is too small, the area extending radially of outer coil 55 will become small, and the unheated area in the radial direction will become too wide. If the ratio of radius of curvature R5 is too large, the area extending circumferentially of curved portion 58 will become small. The distance between adjacent outer coils 55 will increase, and the unheated area will become too wide. Therefore, to ensure the heating area of ​​pot 10 by outer coil 55, it is preferable to set the ratio of radius of curvature R5 to radius of curvature R4 within the above range.

[0055] 6, the width W1 of the curved portion 58 from the inner peripheral portion 55a to the outer peripheral portion 55b of the outer coil 55 is wider than the width W2 of the inner portion 56 and the outer portion 57. Therefore, in the outer coil 55, the heating area in the circumferential direction is wider than the heating area in the radial direction.

[0056] In this way, when the circumferential heating area formed by the curved portion 58 is wider than the radial heating area formed by the inner portion 56 and the outer portion 57, the thickness of the curved portion 58 becomes thinner from the radial inside to the radial outside.

[0057] FIG. 7 is a diagram showing a cross section of the outer coil 55 taken along the major axis a3.

[0058] The circumferential width W1 of the curved portion 58 is wider than the radial width W2 of the inner portion 56 and the outer portion 57, so when the number of coil turns is the same, the thickness T1 of the outer peripheral portion 58a of the curved portion 58 is thinner than the thickness T2 of the inner peripheral portion 58b of the curved portion 58 in the circumferential direction of the pot accommodating portion 41.

[0059] The thickness of the curved portions 58 becomes thinner from the inside to the outside in the circumferential direction of the outer coil 55. In this way, by expanding the surface area of ​​the curved portions 58 in the circumferential direction more than the surface areas of the inner portion 56 and the outer portion 57, the gap between adjacent outer coils 55 can be reduced.

[0060] FIG. 8 is a cross-sectional view of the protective frame 40 in which the coil 50 and the ferrite holder 60 are assembled, taken along the major axis a3 of the outer coil 55. As shown in FIG.

[0061] 8, the sensor mounting portion 41e is disposed circumferentially along the major axis a3 of the curved portion 58. By configuring the outer coil 55 as described above, the outer circumferential portion 55b of the curved portion 58 can be easily brought close to the mounting portion 41e. The gap S between the outer circumferential portion 55b of the curved portion 58 and the mounting portion 41e can be set within a range that provides good detection response by the temperature sensor.

[0062] It is preferable that the gap S between the curved portion 58 and the mounting portion 41e be set to a distance of 20 mm or less and as short as possible. If the gap S is made too small, manufacturing errors in the coil may hinder the assembly of the coil to the protective frame 40.

[0063] As shown in FIGS. 4 and 8, outer coil 55 is formed in a curved shape along the curved surfaces extending in the circumferential direction of side portion 41b and curved portion 41c of pot accommodating portion 41.

[0064] In the case of outer coil 55 described above, repeated switching between a heated state and an unheated state causes curved portion 58 of outer coil 55 to deform in a direction away from pot accommodating portion 41. This may result in insufficient heating of the separated portion of the coil.

[0065] In other words, the applicant of the present application discovered a new problem in that when an outer coil 55 is used in which the radius of curvature R5 of the curved portions 58 at both circumferential ends is smaller than the radius of curvature R4 of the inner and outer portions 56 and 57 at both radial ends, and the thickness of the curved portions 58 becomes thinner from the radial inside to the radial outside of the coil, deformation occurs at the circumferential ends (curved portions 58) of the coil.

[0066] During cooking (heating), the coil may heat up to near the melting temperature of the insulating layer (e.g., 120°C) due to heat generated by the coil itself or radiant heat from the heated pot, resulting in a temperature difference between the unheated state and the unheated state. This temperature difference has led to new findings that distortion is likely to occur in curved portion 58, where the curvature of the coil changes rapidly. Furthermore, because the thickness of curved portion 58 becomes thinner from the inner periphery to the outer periphery, the number of strands is smaller and the insulating layer is more likely to melt. In other words, the curved portion is more susceptible to deformation.

[0067] In contrast, in this embodiment, ferrite holder 60 is provided with coil pressing portion 67 that is positioned close to the outside (opposite side of pot accommodating portion 41) of circumferentially outer end (top) 58a of curved portion 58, thereby suppressing deformation of curved portion 58. As shown in FIG. 2, ferrite holder 60 is positioned directly below coil 50 and accommodates ferrite core 91 (see FIG. 9) for converging magnetic flux from coil 50.

[0068] Fig. 9 is a bottom view of the ferrite holder 60 attached to the protective frame 40. Fig. 10 is a perspective view of the ferrite holder 60 from below. Fig. 11 is a perspective view of the ferrite holder 60 attached to the protective frame 40.

[0069] The ferrite holder 60 includes a central portion 61, first to third holding portions 62 to 64 that hold the ferrite core 91, and a coil pressing portion 67. Arranging multiple ferrite cores for each coil 50 is effective in suppressing the concentration of magnetic flux generated by energizing the coil 50 and the leakage of magnetic flux to the outside of the casing 21. Therefore, the first to third holding portions 62 to 64 are provided to correspond to each coil 50. Each of the first to third holding portions 62 to 64 has a slot shape, and the ferrite core is housed in the slot. The ferrite holder 60 further includes a boss receiving portion 60a for fixing to the protective frame 40 and a screw fastening portion 60b for screwing in the reflector 70 shown in FIG. 12.

[0070] The central portion 61 is an annular portion centered on the axis B. The central support portion 45 of the protective frame 40 is disposed in the internal space of the central portion 61 so as to pass through it.

[0071] 9 and 10, the first holding portions 62 protrude radially from the central portion 61. Three first holding portions 62 are provided at equal intervals in the circumferential direction around the central portion 61. Each first holding portion 62 has a radial portion 62a extending radially along the bottom portion 41a of the protective frame 40, and an extending portion 62b extending further radially from the outer end of the radial portion 62a and extending along the side portion 41b (axis B) of the protective frame 40.

[0072] The first retaining portion 62 includes a pair of sidewall portions 62c, a connecting portion 62d, an elastic piece 62e, and a retaining portion 62f. The pair of sidewall portions 62c extend from the radial portion 62a to the extending portion 62b. The connecting portion 62d connects the ends of the sidewall portions 62c on the protective frame 40 side. The retaining portion 62f protrudes inward from the end of the sidewall portions 62c opposite the connecting portion 62d. The elastic piece 62e is formed from a part of the connecting portion 62d and biases the ferrite core toward the retaining portion 62f. The connecting portion 62d, the elastic piece 62e, and the retaining portion 62f are provided on the radial portion 62a and the extending portion 62b, respectively.

[0073] The second retaining portion 63 has a first circumferential portion 63a and a second circumferential portion 63b extending generally circumferentially from both radially outer ends of the side wall portion 62c of the radial portion 62a. The first and second circumferential portions 63a, 63b each include an outer peripheral wall 63c, a bottom wall 63d, a retaining portion 63f, and an elastic piece 63e. The outer peripheral wall 63c surrounds the outer periphery of the ferrite core. The bottom wall 63d closes a portion of the end of the outer peripheral wall 63c facing the protective frame 40. The retaining portion 63f protrudes inward from the end of the outer peripheral wall 63c opposite the bottom wall 63d. The elastic piece 63e extends radially from the bottom wall 63d and biases the ferrite core toward the retaining portion 63f.

[0074] The third holding portions 64 are connected between adjacent second holding portions 63 via connecting portions 65. The third holding portions 64 extend radially. Three third holding portions 64 are provided at equal intervals in the circumferential direction around the axis B. The third holding portions 64 are arranged with their circumferential positions offset from the first holding portions 62. The third holding portions 64 have a radial portion 64a extending radially along the curved portion 41c of the protective frame 40, and an extending portion 64b extending further radially from the outer end of the radial portion 64a and extending along the side portion 41b (axis B) of the protective frame 40.

[0075] The third retaining portion 64 includes a pair of side wall portions 64c, a connecting portion 64d, an elastic piece 64e, and a retaining portion 64f. The pair of side wall portions 64c extend from the radial portion 64a to the extending portion 64b. The connecting portion 64d connects the ends of the side wall portions 64c on the protective frame 40 side. The retaining portion 64f protrudes inward from the end of the side wall portions 64c opposite the connecting portion 64d, toward the inside of the side wall portion 62c. The elastic piece 64e is formed from a portion of the connecting portion 64d and biases the ferrite core toward the retaining portion 64f.

[0076] 9 and 11, the first holding portion 62 is arranged along the longitudinal axis of the inner coil 51. The radial portion 62a is located from outside the apex of the inner portion 52 to within the inner diameter portion of the inner coil 51. The radial portion 62a is arranged to correspond to the inner portion 52 of the inner coil 51. The extending portion 62b is located from outside the apex of the outer portion 53 to within the inner diameter portion of the inner coil 51. The extending portion 62b is arranged to correspond to the outer portion 53 of the inner coil 51.

[0077] The second holding portion 63 is disposed along the short axis portion of the inner coil 51. The first and second circumferential portions 63a, 63b are disposed between two circumferentially adjacent radial portions 62a at positions corresponding to the curved portion 54 of the inner coil 51 and the inner portion 56 of the outer coil 55.

[0078] The third holding portion 64 is disposed along the major axis portion of the outer coil 55, between the first circumferential portion 63a and the second circumferential portion 63b that are adjacent in the circumferential direction. The radial portion 64a is located from outside the apex of the inner portion 56 to within the inner diameter portion of the outer coil 55. The radial portion 64a is disposed corresponding to the inner portion 56 of the outer coil 55. The extending portion 64b is located from outside the apex of the outer portion 57 to within the inner diameter portion of the outer coil 55. The extending portion 64b is disposed corresponding to the outer portion 53 of the outer coil 55.

[0079] Fig. 12 is a perspective view of the ferrite holder 60 when viewed from a direction in which the outer coil 55 faces forward. Fig. 13 is a perspective view of the ferrite holder 60 when viewed from a direction in which the coil pressing portion 67 faces forward.

[0080] As shown in Fig. 12, the coil pressing portions 67 are provided at positions corresponding to the pair of curved portions 58 of the outer coil 55. The coil pressing portions 67 are connected to the radially outer side of the outer peripheral wall 63c of the second holding portion 63. The coil pressing portions 67 extend radially in the radial direction. As shown in Fig. 10, the coil pressing portions 67 extend along the curved portions 41c and side portions 41b (axis B) of the protective frame 40.

[0081] 9, six coil holding portions 67 are provided at equal intervals in the circumferential direction around the axis B. The coil holding portions 67 are arranged with their circumferential positions offset from the first holding portions 62 and the third holding portions 64. Between adjacent coil holding portions 67, the first holding portions 62 (extension portions 62b) and the third holding portions 64 are arranged alternately.

[0082] 13, the coil pressing portion 67 includes a first pressing portion 67a, a second pressing portion 67b, a first connecting portion 67c, a second connecting portion 67d, a first opening 67e, and a second opening 67f. The first pressing portion 67a and the second pressing portion 67b are spaced apart by a predetermined width W3 that corresponds to the circumferential width W2 of the curved portion 58 of the outer coil 55.

[0083] First retaining portion 67a and second retaining portion 67b are plate-shaped side walls that extend radially and protrude outward from pot accommodating portion 41. Thickness T3 (circumferential dimension) of first retaining portion 67a and second retaining portion 67b is set to 1.5 mm or more and 3.5 mm or less. If it is less than 1.5 mm, coil retaining portion 67 does not have enough rigidity to withstand deformation of outer coil 55, making it difficult to suppress coil deformation. If it exceeds 3.5 mm, the area of ​​outer coil 55 covered by first retaining portion 67a and second retaining portion 67b increases, which may result in reduced heat dissipation.

[0084] As shown in Fig. 12, the first pressing portion 67a and the second pressing portion 67b have a predetermined cross-sectional height (dimension along the axis B). The cross-sectional height H1 of the tip of the first pressing portion 67a and the second pressing portion 67b is set to be 20 mm or more and 30 mm or less. If it is less than 20 mm, the coil pressing portion 67 does not have enough rigidity against deformation of the coil, and it is difficult to suppress deformation of the coil. If it exceeds 30 mm, it is difficult to arrange the coil pressing portion 67 in the limited space between the casing 21 and the protective frame 40.

[0085] 8 and 13, the first pressing portion 67a is arranged to abut near the circumferentially outer end (apex) 58a of the curved portion 58 of the outer coil 55. The second pressing portion 67b is arranged to abut near the inner circumferential portion 58b of the curved portion 58 of the outer coil 55. The second connecting portion 67d is arranged to abut at a radial position corresponding to the major axis a3 of the outer coil 55, between the outer circumferential portion and the inner circumferential portion of the curved portion 58 of the outer coil 55. As a result, the first pressing portion 67a and the second connecting portion 67d press the outer circumferential portion and the inner circumferential portion of the curved portion 58 of the outer coil 55, and the second connecting portion 67d presses the area between the apex 58a and the inner circumferential portion 58b of the curved portion 58 of the outer coil 55 by a surface.

[0086] The vicinity of the outer periphery refers to a width of 4 to 10 mm in the circumferential direction centered on the apex 58a of the curved portion 58. The vicinity of the inner periphery refers to a width of 3 to 10 mm in the circumferential direction centered on the apex on the inner periphery side of the curved portion 58. The radial position corresponding to the major axis a3 where the second connecting portion 67d is disposed includes a distance from the major axis a3 in the direction of the minor axis a4 of 20 mm or less.

[0087] The term "contacting" includes a case where the outer coil and the coil retainer 67 are spaced apart enough that the outer coil 55 is considered not to be substantially deformed. For example, the distance between the curved portion 58 and the coil retainer 67 may be such that deformation is permitted to the extent that insufficient heating does not occur due to the distance between the curved portion 58 and the protective frame 40. In this embodiment, the coil retainer 67 and the outer coil 55 are set to interfere with each other by 0.3 mm. This ensures that deformation is suppressed even when the thickness of the coil or the dimensions of the coil retainer vary due to manufacturing errors.

[0088] 12, the first connecting portion 67c is provided on the base end side of the first and second pressing portions 67a, 67b and radially inward of the first and second pressing portions 67a, 67b. The first connecting portion 67c extends along the circumferential direction of the protective frame 40 to connect the first and second pressing portions 67a, 67b.

[0089] The second connecting portion 67d is provided at the radially outer tip portions of the first and second pressing portions 67a, 67b. The second connecting portion 67d extends in the circumferential direction of the protective frame 40 to connect the tip portions of the first and second pressing portions 67a, 67b. A dimension H2 in the radial direction (direction of axis B) of the second connecting portion 67d is set so as to substantially cover the curved portion 58 of the outer coil 55.

[0090] The first opening 67e is defined by the pair of opposing surfaces of the first pressing portion 67a and the second pressing portion 67b, the first connecting portion 67c, and the outer peripheral wall 63c of the second holding portion 63. The second opening 67f is defined by the pair of opposing surfaces of the first pressing portion 67a and the second pressing portion 67b, the first connecting portion 67c, and the second connecting portion 67d.

[0091] As shown in Figure 2, a reflector 70 is placed directly below ferrite holder 60 to prevent the high-frequency magnetic field generated by coil 50 from adversely affecting peripheral equipment. Reflector 70 has an integrated structure made by bending a single metal sheet. Reflector 70 is made of a material with lower electrical resistance than pot 10, such as copper or aluminum.

[0092] When rice cooker body 20 is assembled, the position of coil 50 is fixed by sandwiching coil 50 between ferrite holder 60 and pot accommodating portion 41. In this embodiment, with boss 41d of pot accommodating portion 41 received in boss receiver 60a of ferrite holder 60, boss 41d, the screw hole of reflector 70, and screw fastening portion 60b of ferrite holder 60 are fastened together to fix them in place.

[0093] The rice cooker 1 configured in this manner has the following features.

[0094] Coil retainer 67 can suppress deformation that is likely to occur when heated by electrical current, particularly at the circumferential ends of outer coil 55. For example, if a resin such as varnish applied to outer coil 55 to maintain its curved state along the shape of pot accommodating section 41 softens due to heating, and the circumferential end of outer coil 55 (curved portion 58) deforms in a direction away from the curved shape of pot accommodating section 41, the end of outer coil 55 will come into contact with coil retainer 67. This allows coil retainer 67 to suppress deformation of outer coil 55.

[0095] Outer coil 55 has a major axis a3 circumferentially around pot 10 and a minor axis a4 radially around pot 10, so that the radius of curvature R5 of outer coil 55 in the circumferential direction is smaller than the radius of curvature R4 of the minor axis a4 of outer coil 55 in the radial direction. In other words, the curvature of outer coil 55 in the circumferential direction changes more rapidly than in the radial direction. With repeated use (repeated switching between heated and unheated states), distortion is likely to occur at the circumferential end (curved portion 58) of outer coil 55, where the curvature changes rapidly, and therefore the effect of coil retainer 67 in suppressing deformation of outer coil 55 becomes more pronounced.

[0096] The thickness T1 of the circumferential outer end (top) 58a of the curved portion 58, where the width W1 of the outer coil 55 is longer, is thinner and more easily deformed than the thickness T2 of the circumferential inner end 58b of the curved portion 58, and therefore the effect of the coil holding portion 67 in suppressing deformation of the coil is more pronounced.

[0097] By providing a gap between the first pressing portion 67a and the second pressing portion 67b that form part of the coil pressing portion 67, deformation of the outer coil 55 can be suppressed without impeding the heat dissipation properties of the outer coil 55.

[0098] Since the coil retaining portion 67 is provided on the ferrite holder 60, no special component is required for providing the coil retaining portion 67, and an increase in the number of components can be suppressed.

[0099] Since the outer coil 55 is located close to the sensor (mounting portion) 41e, the temperature of the outer coil 55 can be detected by the sensor (mounting portion) 41e with higher accuracy than when the outer coil 55 is located away from the sensor (mounting portion) 41e.

[0100] 7, the gap S between the outer coil 55 and the sensor (mounting portion) 41e is set to 3 mm or more and 20 mm or less, so that the gap S between the outer coil 55 and the sensor (mounting portion) 41e is appropriately set. If it is less than 3 mm, the assembly of the outer coil is hindered, and if it exceeds 20 mm, the accuracy of temperature detection by the sensor (mounting portion) 41e is reduced.

[0101] In the above-described embodiment, the coil holding portion 67 is described as having a first holding portion 67a, a second holding portion 67b, and a second connecting portion 67d, but this is not limited to this and the coil holding portion 67 may be configured with only one of the first holding portion 67a or the second holding portion 67b.

[0102] In the above-described embodiment, the coil holding portion 67 has a configuration having a first opening 67e and a second opening 67f, but this is not limited to this, and the coil holding portion 67 does not have to have the first and second openings 67e, 67f.

[0103] In the above embodiment, the coil pressing portion 67 is provided on the ferrite holder 60, but the present invention is not limited to this and the coil pressing portion 67 may be provided on a separate member.

[0104] In the above-described embodiment, the inner portion 56 and the outer portion 57 of the outer coil 55 have the same radius of curvature, but this is not limited to this. For example, the inner portion 56 and the outer portion 57 may have different radii of curvature, such as an egg shape in which the radius of curvature of the inner portion 56 is smaller than the radius of curvature of the outer portion 57.

[0105] In the above-described embodiment, a configuration in which the pair of curved portions 58 of the outer coil 55 have the same radius of curvature has been described, but this is not limited to this, and the pair of curved portions 58 of the outer coil 55 may each be configured with a different radius of curvature.

[0106] The cooking device 1 of the present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0107] 1 Cooker 10. Hot Pot 24 Storage section 55 outer coil (coil) 60 Ferrite holder 67 Coil holder 67a First holding part 67b Second holding part a3 long axis a4 short axis A axis B axis W1 width W2 width

Claims

1. a cylindrical storage section with a bottom for storing a pot; a non-circular coil arranged circumferentially around the axis of the storage section on the outer surface opposite the pot in the storage section, for induction heating the pot; a coil pressing portion located at a curved portion of the coil having a small radius of curvature and adjacent to the coil from an outer surface side of the coil, the coil pressing portion has a first pressing portion adjacent to the outer circumferential side of the coil and a second pressing portion adjacent to the inner circumferential side of the coil, A separation distance W3 between the first pressing portion and the second pressing portion corresponds to a circumferential width W1 of the curved portion of the coil. Heating cooker.

2. The cooking device according to claim 1 , wherein the coil has a major axis in a circumferential direction of the pot and a minor axis in a radial direction of the pot.

3. The cooking device according to claim 1 , wherein the width of the coil in the circumferential direction of the pot is greater than the width of the coil in the radial direction of the pot.

4. a ferrite holder for holding a ferrite core disposed outside the coil; The cooking device according to claim 1 , wherein the coil pressing portion is provided on the ferrite holder.

5. A sensor that contacts the pot is disposed in the storage section, The cooking device according to claim 1 , wherein the coil is provided in proximity to the sensor.

6. 6. The cooking device according to claim 5, wherein a gap between the coil and the sensor is set to be 3 mm or more and 20 mm or less.

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