TW202103618A - Cooking device - Google Patents

Abstract

The present disclosure provides a cooking device which can improve a heating performance of a pot. The cooking device (rice cooker (10)) includes: a receiving portion (22) for receiving the pot (15), and a plurality of coils (25A, 25B). Each of the coils (25A, 25B) is ring-shaped and includes: a first portion (26), which is curved with a first curvature radius (r1) to protrude toward an axis (A) of the receiving portion (22) and then extends along a bottom wall (24a) to pass through the bottom wall; a second portion (27), which is curved with a second curvature radius (r2) smaller than the first curvature radius (r1) and extends along an outer peripheral wall (24b); an arc-shaped third portion (28), which is connected to a first end (26a) of the first portion (26) and a first end (27a) of the second portion (27); and an arc-shaped fourth portion (29), which is connected to a second end (26b) of the first portion (26) and a second end (27b) of the second portion (27).

Description

Cooker

The invention relates to a cooker.

Patent Document 1 discloses an electric rice cooker in which three coils are arranged at intervals in the circumferential direction at the bottom of a bottomed cylindrical rice cooker. In this rice cooker, while one of the three coils is energized and the remaining coils are de-energized, the energized state is switched in a predetermined order, and the rice cooker is inductively heated by the coil.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Application Publication No. 2018-61573

In view of this, our inventors devoted themselves to further research, and proceeded to develop and improve, hoping to develop a better invention to solve the above problems, and after continuous experimentation and modification, the present invention came out.

The problem to be solved by the invention

The heating device of Patent Document 1 describes that a part of the rice cooker is intensively heated by switching the energized state of the coil, but there is room for improvement in the heating performance of the coil to the rice cooker.

The subject of the present invention is to improve the heatability of a pot in a cooker equipped with a plurality of coils.

Means used to solve the problem

One aspect of the present invention provides a cooking device including: a receiving portion having a bottom wall and a cylindrical outer peripheral wall rising from the outer periphery of the bottom wall, and accommodating a bottomed cylindrical pot; and a plurality of coils, On the outer surface side of the accommodating portion, the coils are arranged in a circumferential direction with the axis of the accommodating portion as the center. When viewing the receiving part in the direction of extension, it is bent at a first radius of curvature so as to protrude toward the axis of the receiving part, and extends along the bottom wall in a way that crosses the bottom wall; the second part, It is curved with a second radius of curvature smaller than the first radius of curvature and extends along the outer peripheral wall; the arc-shaped third part is on the side of the first part in the circumferential direction of the receiving part The first end of the second part is connected to the first end of the one side of the second part; and the arc-shaped fourth part, in the circumferential direction of the receiving portion, is connected to the first end on the other side of the first part The two ends are connected to the second end on the other side of the second part.

In this cooker, the first part locally heats the bottom part of the pot, the second part locally heats the side part of the pot, and the third and fourth parts locally heat the bottom part to the side part of the pot. Since the first radius of curvature of the first part is greater than the second radius of curvature of the second part, the heating area of the bottom portion of the pot can be ensured to be wider. Therefore, it is possible to improve the heatability on the bottom surface side of the pan, which is important in heating cooking.

The first part to the fourth part are all arc-shaped, and there is no straight part in the coil. When the coil is manufactured, in the case where there is a straight portion in the coil, the tension becomes too little at the straight portion, on the other hand, the tension becomes too much at both ends of the straight portion. However, in this method, since there is no straight portion, it is possible to wind a single wire or a twisted wire by applying a predetermined tension to a predetermined portion. As a result, a coil of a predetermined shape can be reliably manufactured, and the productivity of the coil can be improved.

The ratio of the first radius of curvature to the second radius of curvature is 100% or more and 160% or less. According to this method, it is possible to effectively ensure the heating area of the bottom portion of the pot by the first part.

In the direction in which the axis of the receiving portion extends, the thickness of the inner peripheral portion of the third portion is thicker than the thickness of the outer peripheral portion of the third portion, and the thickness of the inner peripheral portion of the fourth portion is greater than the thickness of the inner peripheral portion of the fourth portion. The thickness of the outer periphery of the fourth part is thick. Specifically, the thickness of the third portion and the thickness of the fourth portion each gradually become thinner from the inner peripheral portion to the outer peripheral portion. According to this aspect, the number of single wires per unit area on the bottom surface side of the pot is larger than the number of single wires per unit area on the side surface side, so the heating amount can be ensured. In addition, on the side of the pan, although the number of single wires per unit area is reduced, since the range in which the coil can be arranged can be expanded, the heating area can be secured. In addition, on the side of the pan, the flexibility of the coil is improved due to the decrease in the number of single wires, so that the adhesion to the outer surface shape from the bottom wall to the outer peripheral wall can be improved.

Only two such coils are provided. In addition, a sensor is provided that penetrates the outer peripheral wall and detects the temperature of the pot. When the storage portion is viewed in the direction extending from the axis of the storage portion, the two coils are relatively The center of the bottom wall is symmetrically arranged with the reference line of the sensor. According to this aspect, the bottom surface side of the pan can be heated by the two coils without bias. In addition, it is possible to unbiasedly detect the heating temperature of the pot by the two coils by one sensor.

The gap between the third part or the fourth part closest to the sensor and the sensor is 20 mm or less. As described above, by making the thickness of the outer peripheral portion of the third portion and the fourth portion thinner than the thickness of the inner peripheral portion, it is possible to enlarge the heating area of the side portion and bring it closer to the sensor. Furthermore, if the arrangement of the third part or the fourth part and the sensor is configured in this manner, the responsiveness when the temperature of the pot heated by the coil is detected by the sensor can be improved.

The thickness of the first portion and the thickness of the second portion in the direction in which the axis of the accommodating portion extends is uniform from the inner peripheral portion to the outer peripheral portion, and the density ratio of the single wires constituting the first portion is constituted The density of the single wires of the second part is high. According to this aspect, the heating amount per unit area of the bottom part of the pot can be ensured, and the heating area of the side part of the pot can be ensured.

Invention effect

In the cooker of the present invention, since the first radius of curvature of the first portion is larger than the second radius of curvature of the second portion, it is possible to improve the heatability of the bottom surface side of the pot by the plurality of coils. In addition, since there is no straight portion in the coil, the productivity of the coil can be improved.

Regarding the technical means of our inventors, several preferred embodiments are described in detail below in conjunction with the drawings, in order to provide a thorough understanding and approval of the present invention.

Hereinafter, embodiments of the present invention will be described in accordance with the drawings.

Fig. 1 shows a rice cooker 10 as an example of a cooking device according to an embodiment of the present invention. The rice cooker 10 includes a rice cooker main body 20 equipped with a rice cooker (pot) 15 and a lid 35 that is attached to the rice cooker main body 20 in an openable and closable manner. The rice cooker main body 20 is provided with a plurality of (two in this embodiment). A) Multi-coil type with coils 25A and 25B. In this embodiment, the heatability of the rice cooker 15 is improved by optimizing the shape of the coils 25A and 25B.

(Outline of rice cooker)

As shown in FIG. 1, the rice cooking pot 15 is made of a magnetic material, and is an integral structure formed by pressing or casting. The rice cooking pot 15 has a bottomed cylindrical shape, and includes a disc-shaped bottom surface portion 16 and a side surface portion 17 rising from the outer periphery of the bottom surface portion 16. The side surface portion 17 has a cylindrical shape having an axis passing through the center of the bottom surface portion 16.

The rice cooker main body 20 includes a bottomed cylindrical receiving portion 22 for detachably receiving the rice cooking pot 15 in the exterior body 21. By accommodating the rice cooking pot 15 on the inner surface side of the accommodating portion 22, the axis A of the protection frame 24 (the accommodating portion 22) coincides with the axis of the rice cooking pot 15. The accommodating portion 22 is provided at the lower part of the opening formed on the upper surface of the exterior body 21. The accommodating portion 22 includes an inner carcass 23 located at a distance from the upper portion of the side portion 17 and a protective frame 24 located at a position separated from the bottom portion 16 and the lower portion of the side portion 17. The inner carcass 23 is made of metal and has a cylindrical shape with a uniform diameter. The protective frame 24 is made of resin (non-conductive material), and is in the shape of a tray arranged at the lower end of the inner body 23.

2 and 3, in the protection frame 24, on the outer surface side opposite to the inner surface side where the rice cooker 15 is housed, two coils 25A are arranged in a circumferential direction around the axis A of the protection frame 24, 25B. 1, a holder 31 holding a ferrite core 30 is arranged outside the coils 25A, 25B, respectively, and the coils 25A, 25B are held (fixed) between the holder 31 and the protective frame 24. The coils 25A and 25B generate eddy currents by energizing high-frequency currents, and induce induction heating of the rice cooking pot 15.

As shown in FIG. 1, the cover 35 is rotatably attached to the hinge connection portion 36 on the back of the rice cooker main body 20 on the right side in FIG. 1. The lid 35 includes a heat dissipation plate 37 on the inner surface side (the lower side in FIG. 1) facing the rice cooking pot 15. An inner cover 38 that closes the opening of the upper end of the rice cooking pot 15 is provided on the lower side of the heat dissipation plate 37. With respect to the cover body 35, the inner cover 38 may be a structure that can be detached and detached, or a structure that cannot be detached and detached. A cover heater 39 is arranged on the upper surface of the heat dissipation plate 37, and the cover heater 39 heats the inner cover 38 through the heat dissipation plate 37 and evaporates the dew water adhering to the inner cover 38.

1, in the rice cooker 10, two sensors 41 and 42 are arranged as a detection unit that detects the temperature in the rice cooker 15. The first sensor 41 is arranged in the rice cooker main body 20, and the second sensor 42 is arranged in the lid 35. The sensor (side sensor) 41 is arranged to penetrate the protective frame 24 and contact the outer surface of the rice cooking pot 15, and detect the rice temperature or the rice temperature containing water inside through the rice cooking pot 15. The sensor 42 is arranged to be in contact with the heat dissipation plate 37 and detects the temperature in the rice cooker 15 (the space between the heat dissipation plate 37 and the inner cover 38) through the heat dissipation plate 37.

The rice cooker 10 is provided with a control board 44 including a control unit (not shown). The control board 44 of the present embodiment is arranged on the front side of the rice cooker main body 20 by the holder 45, but may be arranged on the back side of the rice cooker main body 20, or may be arranged in the lid 35. The control unit is composed of a single or multiple microcomputers and other electronic devices. The control unit controls the coils 25A, 25B and the lid heater 39 based on the detected temperatures of the sensors 41 and 42 to perform a rice cooking process including a preheating process, a high-fire heating (increasing temperature) process, a boiling maintenance process, and a rice braising process.

When the rice cooking process is executed, the control unit alternately switches the energized state such that one of the two coils 25A and 25B is energized and the other is energized. That is, the first energized state of the coil 25A is electrically connected to cut off the coil 25B and the second energized state of the coil 25B is electrically connected to cut off the coil 25A is alternately repeated. These switching cycles may be different for each process, or may be the same in all processes. However, it is preferable that, in the high-fire heating step in which the temperature in the rice cooking pot 15 is rapidly raised, the switching cycle is changed compared to a step other than the high-fire heating step in which the inside of the rice cooker 15 is maintained (temperature adjusted) at a predetermined temperature. long.

Generally speaking, the distribution boards installed in Japanese households are mostly 20 amps, and the sockets are mostly 15 amps. Therefore, in electrical equipment including this kind of rice cooker 10, the maximum rated power that can be input per unit time is 1500W. In the case of a rice cooker using one coil covering the entire bottom portion 16, the entire rice cooker 15 is induction-heated with a heating amount corresponding to the rated power. In contrast, in the rice cooker 10 of the present embodiment, since the rated power is input to one of the two coils 25A and 25B at the maximum, the corresponding 1/2 of the heating area of the rice cooker 15 is set to correspond to the rated power. The heating volume is the largest and concentrated by induction heating. Therefore, compared with the rice cooker using one coil, in the rice cooker 10 of this embodiment, the maximum heating amount per unit area of the rice cooker 15 can be enlarged. As a result, in the present embodiment, it is possible to intensively heat a part of the rice cooking pot 15 with a large amount of heat.

The heating area of the rice cooking pot 15 is a part located in the magnetic field generated by energization of the coils 25A and 25B, and its shape corresponds to the shape of the coils 25A and 25B. In addition, the heating amount of the rice cooker 15 corresponds to the magnetic flux of the coils 25A and 25B, and the magnetic flux corresponds to the number of the single wires 25a (refer to FIGS. 7 to 9) constituting the coils 25A and 25B. The non-heating area other than the heating area in the rice cooking pot 15 is heated by the heat transfer of the heating area. As this non-heating area increases, the heating efficiency of the rice cooker 15 by the coils 25A and 25B decreases. That is, in order to improve the heating efficiency of the rice cooking pot 15, in addition to the input of electric power, the improvement of the heatability on the side of the bottom surface portion 16 of the rice cooking pot 15 is also important. Therefore, in this embodiment, the coils 25A and 25B arranged in the protective frame 24 are configured as follows.

(Outline of protection frame and coil)

As shown in FIGS. 2 and 3, the plurality of coils 25A and 25B have the same structure and are arranged at predetermined positions of the protection frame 24. Since there are two coils 25A and 25B in this embodiment, they are arranged symmetrically with respect to the reference line L extending in the radial direction of the protective frame 24. The protective frame 24 has a shape corresponding to the shape of the outer surface of the lower portion of the rice cooking pot 15.

Specifically, as shown in FIG. 1, the rice cooking pot 15 includes a bottom surface portion 16 and a side surface portion 17 as described above. Among them, the side surface portion 17 roughly includes a first portion 17a, a second portion 17b, and a third portion 17c. The first part 17a is connected to the outer periphery of the bottom surface 16 and has a curved shape gradually increasing in diameter from the lower side to the upper side. The second portion 17b is connected to the upper end of the first portion 17a, and has a conical cylindrical shape whose diameter gradually increases from the lower side to the upper side. The third portion 17c is connected to the upper end of the second portion 17b, and has a cylindrical shape with a uniform diameter from the lower side to the upper side.

1 to 3, the protective frame 24 includes a circular bottom wall 24 a located at a distance from the bottom surface portion 16, and an outer peripheral wall 24 b located at a distance from the side surface portion 17. Among them, the outer peripheral wall 24b has a cylindrical shape rising from the outer periphery of the bottom wall 24a, and includes a first portion 24c corresponding to the first portion 17a and a second portion 24d corresponding to the second portion 17b. The first portion 24c is connected to the outer circumference of the bottom wall 24a, and has a curved shape with a diameter gradually increasing from the lower side to the upper side. The second portion 24d is connected to the upper end of the first portion 24c, and has a conical cylindrical shape whose diameter gradually increases from the lower side to the upper side.

The protective frame 24 includes an attachment portion 24e on which the sensor 41 is attached. The attachment portion 24e is provided in the second portion 24d of the outer peripheral wall 24b, and includes a circular through hole 24f and a cylindrical protrusion 24g that protrudes outward from the periphery of the through hole 24f. As shown most clearly in FIG. 3, the mounting portion 24e is formed in the exterior body 21 having a substantially rectangular shape in plan view when viewed from the direction extending from the axis A of the protection frame 24, and protrudes toward one of the four corners. . By attaching the sensor 41 to the attaching portion 24e, as shown in FIG. 1, the detection portion penetrating the protective frame 24 abuts the second portion 17b of the side surface portion 17. In addition, the sensor 41 is arranged on the rear side of the exterior body 21 in this embodiment, but it may be arranged on the front side of the exterior body 21.

As shown most clearly in FIG. 2, the protection frame 24 is provided with ribs 24h for positioning the coils 25A and 25B, respectively, and bosses 24i for fixing the holder 31. 3, the rib 24h and the boss 24i for the coil 25A, the rib 24h and the boss 24i for the coil 25B are relative to the center (the axis A of the protection frame 24) passing through the bottom wall 24a and the mounting portion 24e (sensor 41) The reference line L is set symmetrically. Ribs 24h are provided on the inner peripheral portion 25b of the substantially elliptical coils 25A, 25B at one end (inside) of the two ends in the short axis direction, and two at the other end (outside). One at each end of the direction. In addition, two ribs 24h are also provided between the pair of coils 25A and 25B. Two bosses 24i are provided on the inner peripheral portion 25b of the coils 25A and 25B on the outer side in the short axis direction, and one on each end in the long axis direction.

As shown in FIGS. 2 to 4, each of the coils 25A and 25B is formed by winding a plurality of single wires 25a (refer to FIGS. 7 to 9) into an asymmetrical elliptical ring shape. The coils 25A and 25B have a substantially elliptical inner peripheral portion 25b and a substantially semicircular outer peripheral portion 25c. A first connecting wire 25d is extended in the inner peripheral portion 25b, and a second connecting wire 25e is extended in the outer peripheral portion 25c. The connection wires 25d and 25e are respectively covered by insulating tubes, and pass through between adjacent coils 25A and 25B to be electrically connected to the control board 44.

The coils 25A and 25B are respectively arranged in the region from the bottom wall 24a to the first portion 24c of the outer peripheral wall 24b of the protective frame 24 so as to heat the region from the bottom portion 16 to the first portion 17a of the side portion 17 of the rice cooking pot 15. As shown most clearly in FIG. 3, when the receiving portion 22 is viewed from the direction extending from the axis A of the receiving portion 22, the two coils 25A, 25B are arranged side by side in the circumferential direction with the axis A of the protection frame 24 as the center. , And are arranged symmetrically with respect to the reference line L.

More specifically, as shown in FIGS. 3 and 4, each coil 25A, 25B includes: a first portion 26 extending along the bottom wall 24a; a second portion 27 extending along the outer peripheral wall 24b; and a first portion connected to them The third part 28 and the fourth part 29. In Figs. 3 and 4, their boundary portions are shown by a one-dot chain line (virtual line). They are all formed in a circular arc shape with a given curvature, but are not limited to a strict circular arc shape, as long as they are substantially circular arc shapes from one end to the other.

When the accommodating portion 22 is viewed from the direction in which the axis A of the accommodating portion 22 extends, the first portion 26 protrudes inwardly toward the axis A of the accommodating portion 22 and is curved with a predetermined radius of curvature (first radius of curvature) r1. The first portion 26 extends along the reference line L so as to cross the bottom wall 24a. The outer peripheral portion 25c of the first portion 26 in the coil 25A and the outer peripheral portion 25c of the first portion 26 in the coil 25B are located at a predetermined interval (for example, 10 mm).

The second portion 27 is located on the opposite side of the first portion 26 in the minor axis direction of the inner peripheral portion 25b, and protrudes in the opposite direction (outward) from the first portion 26, with a radius of curvature ( The second radius of curvature) r2 is curved. The second portion 27 is centered on the axis A of the protection frame 24 and extends along the first portion 24c of the outer peripheral wall 24b.

The third portion 28 is connected to the first end 26a on the side of the first portion 26 and the first end 27a on the side of the second portion 27 in the circumferential direction of the receiving portion 22, and protrudes to the radially outer side of the protective frame 24 In this way, it is curved with a radius of curvature (third radius of curvature) r3 that is smaller than the radius of curvature r2. The first end 26 a of the first part 26 and the first end 27 a of the second part 27 are parts located on the same side (one side) in the front-rear direction of the exterior body 21.

The fourth portion 29 is connected to the second end 26b on the other side of the first portion 26 and the second end 27b on the other side of the second portion 27 in the circumferential direction of the accommodating portion 22, and extends in the radial direction of the protective frame 24. The outward protrusion is curved with a radius of curvature (fourth radius of curvature) r4 that is smaller than the radius of curvature r2. The second end 26 b of the first part 26 and the second end 27 b of the second part 27 are parts located on the side (the other side) opposite to the first ends 26 a and 27 a in the front-rear direction of the exterior body 21.

The ratio of the radius of curvature r1 of the first portion 26 to the radius of curvature r2 of the second portion 27 is set to 100% or more and 160% or less, more preferably 140% or more and 150% or less. As shown by the dotted line in Fig. 10, if the ratio of the radius of curvature is set too small, the third portion 28 and the fourth portion 29 will be far away from the reference line L, so the heating area of the coils 25A and 25B cannot be ensured. The adjacent coil 25A The non-heating area between, 25B becomes too wide. As shown by the one-dot chain line in Fig. 10, if the ratio of the radius of curvature is set too large, the first portion 26 is close to a straight line. Therefore, as described later, the coils 25A and 25B cannot be manufactured with a predetermined tension. Wind the single wire 25a. Therefore, in order to ensure the heating area of the rice cooker 15 by the first portion 26 and to increase the productivity of the coils 25A and 25B, the ratio of the radius of curvature r1 to the radius of curvature r2 is preferably set within the above-mentioned range.

The radius of curvature r3 of the third portion 28 and the radius of curvature r4 of the fourth portion 29 are set to be the same. Therefore, as shown in FIG. 4, the coils 25A and 25B each have a shape symmetrical with respect to the center line C extending in the minor axis direction of the inner peripheral portion 25b. Therefore, it is possible to prevent the heating area from being different on the one end side and the other end side in the direction along the reference line L, so that the rice cooking pot 15 can be heated uniformly.

3 and 5, the first portion 26 extends along the bottom wall 24a and is formed in a substantially flat shape having a thickness. The second portion 27 extends in the circumferential direction of the protective frame 24 along the first portion 24c of the outer peripheral wall 24b, and is formed in a curved shape having a thickness. The thickness Ta of the first portion 26 in the direction in which the axis A of the protective frame 24 extends is uniform from the inner peripheral portion 25b to the outer peripheral portion 25c. The thickness Tb of the second portion 27 in the direction in which the axis A of the protective frame 24 extends is also uniform from the inner peripheral portion 25b to the outer peripheral portion 25c. The thickness Ta of the first portion 26 in this embodiment is the same as the thickness Tb of the second portion 27.

The width W1 of the first portion 26 from the inner peripheral portion 25b to the outer peripheral portion 25c is smaller than the width (creepage distance) W2 of the second portion 27 from the inner peripheral portion 25b to the outer peripheral portion 25c. Referring to FIG. 7, a large number of single wires 25a constituting the first portion 26 are densely wound by applying tension. Referring to FIG. 8, a large number of single wires 25 a constituting the second portion 27 are wound to have more gaps than the first portion 26 by applying a weaker tension than the single wires 25 a of the first portion 26. That is, the density of the element wires 25a constituting the first portion 26 is higher than the density of the element wires 25a constituting the second portion 27. Therefore, even if the thicknesses Ta and Tb are the same and the number of the single wires 25a is the same, the width W1 of the first portion 26 and the width W2 of the second portion 27 are different. In addition, due to the difference in the widths W1 and W2, the heating amount of the first portion 26 per unit area is greater than the heating amount of the second portion 27 per unit area.

Referring to FIG. 4, the third portion 28 and the fourth portion 29 are formed in a line-symmetric plan shape. 6, they extend in the radial direction of the protective frame 24 along the first portion 24c of the outer peripheral wall 24b, and are formed in a curved shape with a thickness. In the direction in which the axis A of the protective frame 24 extends, the thickness Tc1 of the inner peripheral portion 25b of the third portion 28 is thicker than the thickness Tc2 of the outer peripheral portion 25c of the third portion 28. Like the third portion 28, the thickness Tc1 of the inner peripheral portion 25b of the fourth portion 29 is thicker than the thickness Tc2 of the outer peripheral portion 25c of the fourth portion 29. These thicknesses Tc1 and Tc2 are gradually thinner from the inner peripheral portion 25b to the outer peripheral portion 25c, respectively.

The thickness Tc1 of the inner peripheral portion 25b of the third portion 28 and the fourth portion 29 is the thinnest at the central portions 28a, 29a between the first end 26a of the first portion 26 and the first end 27a of the second portion 27. That is, the thickness Tc1 of the inner peripheral portion 25b of the third portion 28 and the fourth portion 29 gradually becomes thinner as the distance from the first portion 26 and the second portion 27 is increased. Similarly, the thickness Tc2 of the outer peripheral portion 25c of the third portion 28 and the fourth portion 29 gradually becomes thinner as they move away from the first portion 26 and the second portion 27, and is the thinnest in the central portions 28a and 29a. 9, the density of a large number of single wires 25 a constituting the third portion 28 and the fourth portion 29 respectively is higher than the density of the single wires 25 a constituting the second portion 27.

In this way, the thickness of the third portion 28 and the thickness of the fourth portion 29 gradually decrease from the inner side to the outer side in the circumferential and radial directions of the coils 25A and 25B. Therefore, even if the number of single wires 25a is the same, the surface area of the third portion 28 and the surface area of the fourth portion 29 can be expanded larger than the surface area of the first portion 26 and the surface area of the second portion 27. As a result, the outer peripheral portion 25c of the third portion 28 and the outer peripheral portion 25c of the fourth portion 29 can be brought close to the sensor 41. In other words, as shown in FIG. 3, the gap S between the outer peripheral portion 25c of the third portion 28 and the outer peripheral portion 25c of the fourth portion 29 and the mounting portion 24e (sensor 41) can be set so that the detection responsiveness of the sensor 41 is good. Within range.

Specifically, the gap S between the third portion 28 and the fourth portion 29 and the sensor 41 is 20 mm or less, and it is preferable to set the distance as short as possible. However, in consideration of the assemblability of the coils 25A and 25B with respect to the protective frame 24, it is preferable to set it to a range of 8 mm or more and 17 mm or less. If the gap S is too small, the assemblability of the coils 25A and 25B with respect to the protective frame 24 may deteriorate due to manufacturing errors of the coils 25A and 25B. If the gap S is set too large, the detection responsiveness of the sensor 41 may deteriorate. In order to prevent these problems, the gap S is preferably set within the above-mentioned range.

Next, an example of a method of manufacturing the coils 25A and 25B will be described. However, the manufacturing method of the coils 25A and 25B is not limited to this.

The coils 25A and 25B are manufactured by a coil manufacturing machine equipped with a bobbin and a feeder. The bobbin includes a first mold having a first surface corresponding to the shape of the inner surface of the coils 25A, 25B, and a second mold having a second surface corresponding to the shape of the outer surface of the coils 25A, 25B. The feeder sends out a twisted wire formed by twisting a plurality of (for example, 32) single wires 25a (refer to FIGS. 7 to 9).

The spool is rotated with a rotating shaft extending in the vertical direction as the center, and the stranded wire is wound with the spool while applying a predetermined tension through the feeder. As a result, coils 25A and 25B having a thickness and shape corresponding to the space between the first mold and the second mold are wound. The winding-start part protruding from the spool constitutes the connecting wire 25d, and the winding-ending part protruding from the spool constitutes the connecting wire 25e. When the winding of the twisted wire ends, the single wire 25a is heated by energization. Thereby, the welding layer of the outer peripheral part of the element wire 25a is melted, and the adjacent element wires 25a are welded to each other. As a result, coils 25A and 25B of predetermined shapes corresponding to the space of the bobbin are formed.

Here, when the coil is D-shaped when viewed from the direction in which the axis A of the protection frame 24 extends, that is, when the first portion 26 is linear, when the stranded wire is wound around the first portion 26, it cannot be twisted. The bonding wire applies tension toward the second portion 27. Moreover, when the twisted wire of the first part 26 is wound, a multi-degree tension is applied to the third part 28 or the fourth part 29 that is wound first. That is, since a predetermined tension cannot be applied to a predetermined portion, the productivity of the coil deteriorates.

In this embodiment, the first part 26 to the fourth part 29 are all circular arc shapes, and there are no straight portions in the coils 25A and 25B. Therefore, it does not happen that the tension becomes too low at the straight portion (the first portion 26) or the tension becomes too much at both ends of the straight portion (the third portion 28 or the fourth portion 29). Therefore, the twisted wire (single wire 25a) can be wound by applying a predetermined tension to a predetermined location. Thereby, the coils 25A and 25B of predetermined shapes can be reliably manufactured, and the productivity of the coils 25A and 25B can be improved.

The rice cooker 10 of the present invention configured as described above has the following characteristics.

The first part 26 locally heats the bottom part 16 of the rice cooking pot 15, the second part 27 locally heats the side part 17 of the rice cooking pot 15, and the third part 28 and the fourth part 29 locally heat the bottom part of the rice cooking pot 15 16 to the side portion 17. Since the first radius of curvature r1 of the first portion 26 is greater than the second radius of curvature r2 of the second portion 27, the heating area of the bottom surface portion 16 of the rice cooking pot 15 can be ensured to be wider. Therefore, it is possible to improve the heatability of the bottom surface portion 16 side of the rice cooking pot 15 which is important in heating cooking. Furthermore, since there are no straight portions in the coils 25A and 25B, productivity can be improved.

The thickness Tc1 of the inner peripheral portion 25b of the third portion 28 and the fourth portion 29 is thicker than the thickness Tc2 of the outer peripheral portion 25c of the third portion 28 and the fourth portion 29. In addition, the thickness of each of the third portion 28 and the fourth portion 29 gradually becomes thinner from the inner peripheral portion 25b to the outer peripheral portion 25c. Therefore, the number of single wires 25a per unit area on the side of the bottom surface portion 16 of the rice cooking pot 15 is greater than the number of single wires 25a per unit area on the side portion 17 side, and therefore the heating amount can be ensured. In addition, although the number of single wires 25a per unit area is reduced on the side surface portion 17 side of the rice cooking pot 15, the range in which the coils 25A and 25B can be arranged can be expanded, and therefore the heating area can be secured. Moreover, on the side surface 17 side of the rice cooking pot 15, the flexibility of the coils 25A, 25B is improved due to the reduction in the number of the single wires 25a, so that the adhesion to the outer surface shape from the bottom wall 24a to the outer peripheral wall 24b can be improved. Sex.

Two coils 25A and 25B are provided, and they are arranged symmetrically with respect to the reference line L passing through the center of the bottom wall 24a and the sensor 41. Therefore, the bottom surface 16 side of the rice cooking pot 15 can be heated by the two coils 25A, 25B without bias. In addition, the heating temperature of the rice cooking pot 15 by the two coils 25A and 25B can be detected by one sensor 41 without bias.

The gap S between the third portion 28 or the fourth portion 29 closest to the sensor 41 and the sensor 41 is 20 mm or less. Therefore, it is possible to improve the responsiveness when the sensor 41 detects the temperature of the rice cooker 15 heated by the coils 25A and 25B.

The thicknesses Ta and Tb of the first portion 26 and the second portion 27 are uniform from the inner peripheral portion 25b to the outer peripheral portion 25c, and the density of the element wires 25a constituting the first portion 26 is higher than the density of the element wires 25a constituting the second portion 27 . Therefore, the heating amount per unit area in the bottom surface part 16 of the rice cooking pot 15 can be ensured, and the heating area in the side surface part 17 of the rice cooking pot 15 can be ensured.

In addition, the rice cooker (cooker) 10 of this invention is not limited to the structure of the said embodiment, Various changes can be made.

For example, the thickness Ta of the first portion 26 and the thickness Tb of the second portion 27 may be different, or may be different at the inner peripheral portion 25b and the outer peripheral portion 25c. The thickness of the third portion 28 and the thickness of the fourth portion 29 may be different, respectively, or may be the same at the inner peripheral portion 25b and the outer peripheral portion 25c.

The radii of curvature of the first part 26 to the fourth part 29 and the density of the single wires 25a constituting them can be changed as needed. In particular, the radius of curvature of the third portion 28 and the radius of curvature of the fourth portion 29 may also be different.

The coil is not limited to two, and three or more coils may be arranged side by side in the circumferential direction with the axis A of the protection frame 24 as the center. In this case, the sensor 41 is preferably arranged in the center of the bottom wall 24 a of the protection frame 24.

In the above-mentioned embodiment, the rice cooker 10 has been described as an example, but as long as it is a cooker equipped with a bottomed cylindrical storage portion and a plurality of coils arranged on the outer surface side of the storage portion, it can be applied and can be used. Get the same effect and effect.

In summary, the technical means disclosed in the present invention can indeed effectively solve the problems of the prior art and achieve the expected purpose and effect. It has not been seen in the publications, has not been used publicly, and has long-term progress before the application. The patent law claims that the invention is correct. Yan filed an application in accordance with the law and prayed that Jun Shanghui would give a detailed examination and grant a patent for invention.

However, the above are only a few preferred embodiments of the present invention, and should not be used to limit the scope of implementation of the present invention, that is, all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the description of the invention are all It should still fall within the scope of the invention patent.

〔this invention〕 10: Rice cooker (cooker) 15: Rice cooking pot (pot) 16: bottom face 17: Side 17a: Part One 17b: Part Two 17c: Part Three 20: The main body of the rice cooker 21: Exterior body 22: Containment Department 23: inner carcass 24: Protective frame 24a: bottom wall 24b: Peripheral wall 24c: part one 24d: second part 24e: Installation Department 24f: Through hole 24g: protrusion 24h: rib 24i: boss 25A, 25B: coil 25a: single line 25b: inner circumference 25c: Peripheral 25d: connection line 25e: connection line 26: Part One 26a: first end 26b: second end 27: Part Two 27a: first end 27b: second end 28: Part Three 28a: central part 29: Part Four 29a: central part 30: Ferrite core 31: Holder 35: Lid 36: Hinge connection part 37: heat sink 38: inner cover 39: Lid heater 41: Sensor 42: Sensor 44: control board 45: Holder A: Axis of the protection frame (receiving part) L: Baseline S: gap r1: the radius of curvature of the first part r2: the radius of curvature of the second part r3: the radius of curvature of the third part r4: the radius of curvature of the fourth part Ta: the thickness of the first part Tb: the thickness of the second part Tc1: The thickness of the inner circumference of the third and fourth parts Tc2: The thickness of the outer circumference of the third and fourth parts

[Figure 1] is a cross-sectional view of a cooking device according to an embodiment of the present invention; [Figure 2] is an exploded perspective view of the protective frame and coil; [Figure 3] is a bottom view of the protective frame and coil; [Figure 4] is a bottom view of a coil; [Figure 5] is a sectional view taken along line V-V of Figure 4; [Figure 6] is a sectional view taken along line VI-VI of Figure 4; [Figure 7] is a partial enlarged view of Figure 5; [Figure 8] is a partial enlarged view of the part of Figure 5 different from Figure 7; [Figure 9] is an enlarged view of Figure 6; Fig. 10 is a bottom view showing a comparative example in the case where the curvature of the first part of the coil is changed.

21: Exterior body

22: Containment Department

24: Protective frame

24a: bottom wall

24b: Peripheral wall

24c: part one

24d: second part

24e: Installation Department

24h: rib

25A, 25B: coil

25b: inner circumference

25c: Peripheral

26: Part One

26a: first end

26b: second end

27: Part Two

27a: first end

27b: second end

28: Part Three

29: Part Four

A: Axis of the protection frame (receiving part)

L: Baseline

S: gap

r1: the radius of curvature of the first part

r2: the radius of curvature of the second part

r3: the radius of curvature of the third part

r4: the radius of curvature of the fourth part

Claims (8)

A cooking device having: The accommodating part has a bottom wall and a cylindrical outer peripheral wall rising from the outer periphery of the bottom wall, and accommodates a bottomed cylindrical pot; and A plurality of coils are arranged side by side in the circumferential direction on the outer surface side of the accommodating portion centered on the axis of the accommodating portion, The multiple coils are ring-shaped, and each have: The first part, when the receiving portion is viewed from the direction in which the axis of the receiving portion extends, is bent at a first radius of curvature so as to protrude toward the axis of the receiving portion, and runs along the bottom wall so as to cross the bottom wall. Extends along the bottom wall; The second part is curved with a second radius of curvature smaller than the first radius of curvature and extends along the outer peripheral wall; The arc-shaped third portion is connected to the first end on one side of the first portion and the first end on the side of the second portion in the circumferential direction of the receiving portion; and The arc-shaped fourth portion is connected to the second end on the other side of the first portion and the second end on the other side of the second portion in the circumferential direction of the receiving portion. The cooker according to claim 1, wherein The ratio of the first radius of curvature to the second radius of curvature is 100% or more and 160% or less. The cooker according to claim 1 or 2, wherein In the direction in which the axis of the receiving portion extends, the thickness of the inner peripheral portion of the third portion is thicker than the thickness of the outer peripheral portion of the third portion, and the thickness of the inner peripheral portion of the fourth portion is greater than the thickness of the inner peripheral portion of the third portion. The thickness of the outer periphery of the fourth part is thick. The cooker according to claim 3, wherein: The thickness of the third portion and the thickness of the fourth portion respectively gradually become thinner from the inner peripheral portion toward the outer peripheral portion. The cooker according to claim 1 or 2, wherein The cooker has only two coils. The cooker according to claim 5, wherein: The cooking device includes a sensor that penetrates the outer peripheral wall and detects the temperature of the pot, When the accommodating part is viewed from the direction in which the axis of the accommodating part extends, the two coils are arranged symmetrically with respect to the center passing through the bottom wall and the reference line of the sensor. The cooker according to claim 6, wherein: The gap between the third part or the fourth part closest to the sensor and the sensor is 20 mm or less. The cooker according to claim 1 or 2, wherein The thickness of the first portion and the thickness of the second portion in the direction in which the axis of the accommodating portion extends is uniform from an inner peripheral portion to an outer peripheral portion, The density of the single wires constituting the first portion is higher than the density of the single wires constituting the second portion.

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