JP2008004407A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker allowing the shape of an induction coil to be stably produced, and capable of ensuring high eating quality. <P>SOLUTION: This rice cooker is manufactured by setting a winding thickness (t) of an aggregate wire 16 constituting a winding of the induction coil 13 larger than a winding width (w) thereof. Thereby, the targeted shape of the induction coil can be stably produced by reinforcing the induction coil 13, and high eating quality can be ensured by concentrating heating energy. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rice cooker having an induction coil for induction heating a pan.

Conventionally, an induction coil in this type of rice cooker is configured by winding a collective wire in which a plurality of strands are combined into a spiral shape, and the winding width is larger than the winding thickness (for example, , See Patent Document 1).
Japanese Patent Laid-Open No. 9-154714

  However, in the conventional configuration, when the induction coil is wound, after the induction coil is wound and the shape is determined, the entire induction coil has a wide and thin shape, so that it is difficult to maintain strength and maintain a stable shape. Had the problem of being difficult. Also, when fixing the coil shape, it is necessary to determine the shape by squeezing the coil wire into a narrow thickness winding jig, making it difficult to produce the induction coil with a predetermined width. there were. Furthermore, the widening of the induction coil widens the heating range to the pan and disperses the heating energy, so the convection of rice and water from the pan bottom to the top of the pan does not reach and the water level line increases. There was also a problem that uneven cooking occurred at the bottom and the top, resulting in poor production.

  This invention solves the said conventional subject, and it aims at providing the rice cooker which can ensure the high taste while being able to produce the shape of an induction coil stably.

  In order to solve the above-mentioned conventional problems, the rice cooker of the present invention is such that the winding thickness of the collecting wire constituting the winding of the induction coil is larger than the winding width.

  As a result, the induction coil can be made strong and the target induction coil shape can be stably produced, and the heating energy can be concentrated to ensure a high taste.

  The rice cooker of the present invention can stably produce the shape of the induction coil and can ensure a high taste.

  1st invention is equipped with the rice cooker main body, the pan detachably accommodated in the rice cooker main body, and the induction coil which carries out induction heating of the pan, The said induction coil is the set which united two or more strands more Constructed by winding the wire in a spiral shape, the collective wire is a rice cooker whose winding thickness is larger than the winding width, thereby strengthening the induction coil and stabilizing the target induction coil shape While being able to produce, it becomes possible to concentrate heating energy and to ensure a high taste.

  In the second invention, in particular, in the first invention, the assembly wire has a ratio of the winding thickness to the winding width of about 1.0 to 3.0, thereby achieving both taste and shape stability of the induction coil. A configuration can be obtained.

  According to a third aspect of the invention, in particular, in the first or second aspect of the present invention, the wire has a conductor diameter of approximately 0.4 mm or less, thereby suppressing self-heating of the induction coil and increasing thermal efficiency. .

  In a fourth aspect of the invention, in particular, in any one of the first to third aspects, the product of the diameter of the conductors of the strands, the number of strands to be assembled, and the number of twists per 30 cm is about 50 or less. As a result, it is possible to obtain a characteristic that the assembly line easily follows the shape of the target induction coil.

  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)
The figure shows a rice cooker in an embodiment of the present invention.

  As shown in FIG. 1, the rice cooker according to the present embodiment includes a rice cooker main body 10 having an open upper surface, a coil base 11 formed into a bottomed cylindrical shape by a non-metallic material, and a removable body in the main body 10. A pot 12 that contains rice 17 and water and an induction coil 13 that is disposed outside the coil base 11 and induction-heats the pot 12 is provided. The induction coil 13 is divided into two facing the bottom of the pan 12 and the side surface as shown in the figure.

  In addition, a circuit board 14 for supplying an electric current for generating an alternating magnetic field in the induction coil 13 and an outer lid 15 that can be opened and closed with respect to the rice cooker body 10 are provided.

  Next, the strand 15 which comprises the induction coil 13 is demonstrated with FIG. The strand 15 includes a conductor 15a having a diameter of 0.3 mm, and an insulating layer 15b and a fusion layer 15c that sequentially cover the entire circumference. As shown in FIG. 3, the assembly line 16 is formed by bundling 34 strands 15 shown in FIG. 2 and twisting them three times for 30 cm. The collecting wire 16 is wound in a spiral shape to constitute the induction coil 13. Here, the collecting wire 16 has a winding thickness t larger than the winding width w.

  In this configuration, the operation during rice cooking will be described.

  Rice cooking is started, and the circuit board 14 starts energizing the induction coil 13. The pan 12 generates heat due to the induction magnetic field. Since the opposing portion of the induction coil 13 mainly generates heat, convection as shown by the arrow in FIG. 1 is generated in the pan 12 and passes between the rice grains 17. That is, it is heated from the side closer to the side surface of the induction coil 13 and rises along the side surface of the pan 12, and further rises from the opposite side of the bottom side of the induction coil 13 that is inside the convection, Convection descending to the outside and inside (the center of the pan 12) is generated.

  In order to improve the taste of rice, all the rice grains 17 in the pan 12 are heated uniformly and heated at a stretch with a strong heating amount to surely break down the starchy substance (amylose) of the rice grains 17 and promote the alpha conversion. Is good. However, as the heating progresses, the starchy material on the surface of the rice grain 17 around the heated portion at the bottom of the pan 12 melts first, and the moisture becomes sticky and the convection stops. The part which rice cooking complete | finishes with sufficient generation | occurrence | production, and cooking unevenness arises. Therefore, it is important to set the convection appropriately. In order to turn the heat flow in the entire pan 12 quickly and reliably, the entire pan 12 is uniformly heated when the convection as shown by the arrow in FIG. It is convenient for.

  In order to become a convection as shown by the arrow in FIG. 1, as described above, it is necessary to place the convection heated in the pan 12 and the rising convection, and the rising heat flow must be lowered and put on the rising convection again. The arrangement of the induction coil 13 has a great influence on the taste. Depending on the width of the induction coil 13, the heating range of the pan 12 changes, and the heating location also changes depending on the positional relationship between the bottom side and the side of the side, and it is determined whether convection occurs well.

  When this convection is strengthened, heated water can be turned at once from the bottom to the top of the pan 12, so that the entire cooking pot 12 is provided with strong heating during cooking necessary to improve the taste of rice. Therefore, the entire inside of the pan 12 is quickly and uniformly heated. Furthermore, even when the amount of rice grains 17 is large and deep, heat can be reliably transferred from the bottom of the pan 12 to the top.

  Here, it is assumed that the induction coil 13 is set to be narrow on both the bottom and the side of the pan. At this time, the heating level per unit area in the heating part increases, and strong upward convection occurs. In addition, by narrowing the heating range, a path is ensured in which the heat flow rising from the bottom of the pan 12 descends again and returns to the bottom of the pan 12, and a large heat flow can be made in the entire pan 12.

  The width of the induction coil 13 is determined by the number of turns of the collecting wire 16 and the width per winding of the collecting wire 16. If the number of turns of the collective wire 16 is small, the inductance value of the induction coil 13 decreases, that is, the resistance value against the high-frequency alternating current decreases, so that the inverter current value increases with respect to the required electric energy, and the induction coil 13 and the circuit board 14 are configured. Since the inverter element that generates heat increases, a certain number of turns is required. Therefore, it is preferable to reduce the width of the induction coil 13 by reducing the width of the collecting wire 16 per turn.

  In this embodiment, the induction coil 13 is described as being divided into two parts. However, when the heating range is narrow, such as when the diameter of the pan 12 is large, sufficient heating cannot be obtained. If the number of divisions is increased, the total amount of heating can be increased by increasing the number of convections.

  Here, the production process for forming the assembly wire 16 into the induction coil 13 will be briefly described. The winding jig used to form the assembly wire 16 has a gap that matches the shape of the induction coil 13, and the assembly wire 16 is wound into the gap. The winding jig gap and the winding thickness t are naturally the same dimensions. When the winding thickness t and the pulling force applied to the collecting wire 16 at the time of winding change, the winding density of the strands 15 changes, so that the winding width w can be set to a width that can cause optimum convection. Make adjustments.

  When the collecting wire 16 is wound up to a predetermined number of turns on the winding jig, a large direct current of about 280 A is passed through the collecting wire 16. As a result, the conductor 15a self-heats, and the fusion layer 15c is melted by the heat, and the adjacent wires 15 are fixed to each other. At this time, by making the winding thickness t of the assembly wire 16 constituting the induction coil 13 larger than the winding width w, a large contact area between the adjacent assembly wires 16 is secured. The ratio of the number of 15 strands of the matching assembly line 16 is increased. As a result, the induction coil 13 has a strong shape that does not easily collapse. In addition, as for the assembly line 16, ratio of the winding thickness t with respect to the winding width w is about 1.0-3.0.

  In addition, regarding the winding width w, the winding thickness t, and the spatial distance d with the pan 12, the winding width w is 3 mm, the winding thickness t is 4 mm, and the spatial distance d is 5.5 mm. It is composed.

  In addition, by setting the diameter of the conductor 15a portion of the strand 15 to 0.4 mm or less, the distance from the surface of the conductor 15a to the center is reduced, but generally high frequency current is concentrated on the surface layer of the conductor 15a. A flowing skin effect is known, and by this skin effect, the diameter of the conductor 15a is reduced and the number of the wires 15 is increased to obtain a predetermined surface area, thereby suppressing the self-heating of the induction coil 13 and thermal efficiency and reliability. Can be improved. That is, the smaller the diameter of the conductor 15a portion of the strand 15 and the greater the number, the better. However, if the number of the strands 15 increases, the processing cost increases, so the setting is made according to the balance between the processing cost and the above effect.

  Furthermore, the cross-sectional shape of the assembly wire 16 is deformed by reducing the product of the diameter (in mm) of the conductor 15a of the strand 15 to the number of strands 15 to be assembled and the number of twists per 30 cm to about 50 or less. This makes it easy to follow the shape even if the ratio between the winding thickness t and the winding width w of the assembly wire 16 is greatly deviated, so that the workability can be improved.

  As described above, in this embodiment, by making the winding thickness t of the assembly wire larger than the winding width w, the dimensional accuracy in the width direction can be determined stably when the induction coil 13 is produced. Strong overall strength is ensured and easy to manage.

  Furthermore, since the convection of rice and water in the pan 10 can be concentrated by reducing the width of the induction coil 13, heating is performed from the bottom of the pan to the top even when the amount of cooked rice is high and the water level line is high. It is possible to reduce the outer diameter of the pot 10 and reduce the size of the rice cooker by the amount that the pot depth can be set deeper. When it is necessary to take a large heating area, such as a large-capacity rice cooker, the induction coil 13 as in this embodiment is not divided into the middle and outer two parts, but divided into three parts and four parts. If this is the case, the heating range is dispersed and the wide range can be heated uniformly, and the self-heating of the induction coil 13 can be easily cooled.

  In addition, when it is desired to reduce the heating area, such as small-capacity rice cooking, the winding density of the induction coil 13 is increased by reducing the winding width of the induction coil 13, and the characteristic value (inductance) of the induction coil 13 can be increased even in a narrow range. Can be secured. In order for the circuit board 14 to operate normally, it is necessary to secure a certain amount of inductance value, but by using this configuration, it is possible to easily configure a circuit having a small heating area.

  Each value of the induction coil 13 described above is a value that can be put to practical use based on the result of the experiment according to each purpose, and the values that substantially correspond to the respective values are the present invention. Belongs to.

  As described above, the rice cooker according to the present invention can stably produce the shape of the induction coil and can ensure a high taste, so that it can easily produce a heating coil for electromagnetic induction heating. Therefore, the present invention can be applied not only to cookers for cooked rice for general household use and business use but also to uses for heating various foods.

Partial sectional view of a rice cooker in an embodiment of the present invention Sectional drawing of the strand which comprises the induction coil of the rice cooker (A) Main part sectional drawing which shows the arrangement | positioning state of the induction coil of the rice cooker (b) The expanded sectional view of the A section in (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rice cooker body 12 Pot 13 Induction coil 15 Wire 15a Conductor 16 Assembly line

Claims (4)

A rice cooker body, a pan that is detachably stored in the rice cooker body, and an induction coil that induction-heats the pan, and the induction coil is a spirally wound assembly of a plurality of strands. The rice cooker is configured by forming a winding thickness larger than the winding width. The rice cooker according to claim 1, wherein the assembly line has a ratio of a winding thickness to a winding width of approximately 1.0 to 3.0. The rice cooker according to claim 1 or 2, wherein the wire has a conductor diameter of approximately 0.4 mm or less. The rice cooker according to any one of claims 1 to 3, wherein a product of the diameter of the conductors of the strands, the number of strands to be gathered, and the number of twists per 30 cm is about 50 or less.