JP3202400B2 - Induction cooker for induction cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating apparatus for an electromagnetic cooker for cooking by heating an object to be heated such as a pot.

[0002]

2. Description of the Related Art An example of an induction heating device for an electromagnetic cooker is shown in FIG. In FIG. 9, the induction heating device 1 includes a litz wire 3 on a coil base 2 formed of a resin having high heat resistance.
Is attached to a heating coil 4 which is wound in a spiral shape. The litz wire 3 is composed of dozens of enamel wires of high insulation type having a diameter of about 0.5 mm. Further, several ferrite rods (not shown) are attached to the lower surface of the coil mount 2, and the ferrite rods absorb and shield leakage magnetic flux generated from the heating coil 4. Have been.

[0003]

However, in the above-mentioned conventional configuration, since the heating coil 4 is formed by using the complicated and expensive litz wire 3, the manufacturing cost of the entire induction heating apparatus 1 is increased. There is a problem. Also,
Since several ferrite rods are mounted on the coil mount 2 to shield the leakage magnetic flux, the number of parts is increased, and the work of mounting these several rods is troublesome.

Accordingly, an object of the present invention is to provide an induction heating device for an electromagnetic cooker which can simplify the entire structure and reduce the manufacturing cost. Another object of the present invention is to provide an induction heating device for an electromagnetic cooker that can simplify a configuration for shielding magnetic flux leakage, can reduce the number of parts, and can greatly improve manufacturing workability. To offer.

[0005]

Induction heating device of an electromagnetic cooker SUMMARY OF THE INVENTION The present invention includes a substrate and a heating coil a strip-shaped copper plate mounted on the upper surface of the substrate formed by spirally formed, the group
Leakage generated from the heating coil provided on the lower surface of the plate
The shield is designed to shield magnetic flux and prevent eddy currents from flowing.
It is characterized by having the formed shielding conductor pattern .

[0006]

According to the above means, the heating coil is formed by forming a strip-shaped copper plate into a spiral shape, so that the configuration of the heating coil and, consequently, the entire configuration of the induction heating device are greatly simplified as compared with the conventional configuration using a litz wire. And the manufacturing cost is greatly reduced, and the overall configuration becomes thin. In addition, a shielding conductor pattern for shielding leakage magnetic flux generated from the heating coil is provided on the lower surface of the substrate on which the heating coil is mounted, and the shape of the shielding conductor pattern is configured such that eddy currents do not easily flow. Compared with the conventional configuration in which a ferrite rod is mounted, the configuration for shielding the leakage magnetic flux is greatly simplified, the number of components is reduced, and the manufacturing workability of the induction heating device is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 6 showing an electric configuration of the electromagnetic cooker, an inverter circuit 1 for supplying a high-frequency current to a heating coil 12 of an induction heating device 11 is shown.
3 is a rectifier 14, a choke coil 15, a smoothing capacitor 16, a resonance capacitor 17, and an IGBT, for example.
And a switching element 18 and the like.
The switching element 18 of the inverter circuit 13 is configured to be turned on / off by a control circuit 19. The control circuit 19 includes, for example, a microcomputer, and has a function as control means for controlling the overall heating operation of the electromagnetic cooker.

In the above configuration, when the inverter circuit 13 is driven by the control circuit 19, a high-frequency current is supplied from the inverter circuit 13 to the heating coil 12, and the high-frequency magnetic flux generated from the heating coil 12 is the object to be heated. For example, acting on a pan (not shown), an eddy current is induced in the pan. Joule heat is generated by the induced eddy current and the electric resistance of the pot itself, and the temperature of the pot itself is increased by the Joule heat, so that the food contained in the pot is heated and cooked. ing.

Here, regarding the induction heating device 11,
This will be specifically described with reference to FIGS. As shown in FIG. 1, the induction heating device 11 is configured such that a heating coil 12 formed by forming a strip-shaped copper plate 21 in a spiral shape is attached and fixed to the upper surface of a printed circuit board 20, for example. In this case, the heating coil 12 is configured such that the flat plate portion of the strip-shaped copper plate 21 is in contact with the upper surface of the printed wiring board 20 (see FIG. 2). Note that the heating coil 12 is
One flat copper plate may be formed by punching in a spiral shape as shown in FIG. 1, or a strip-shaped copper plate 21 may be formed by being bent in a spiral shape. It may be formed in a spiral shape by any suitable method.

A structure for mounting and fixing the heating coil 12 to the printed wiring board 20 will be specifically described with reference to FIGS. As shown in FIGS. 2 and 3, a pair of mounting projections 22 project downward from both sides of the strip-shaped copper plate 21 of the heating coil 12. In this case, a plurality of pairs of the mounting protrusions 22 are provided at a certain interval. On the other hand, the printed wiring board 20 has
A plurality of holes 23 into which the mounting projections 22 are fitted are formed. The copper plate 21 (the heating coil 12) is fixedly mounted on the printed wiring board 20 by fitting the mounting protrusions 22 into the holes 23 and caulking the distal ends of the mounting protrusions 22. . In addition, it is preferable that the copper plate 21 is bonded and fixed to the printed wiring board 19 via an adhesive such as varnish, instead of fitting the mounting protrusion 22 into the hole 23 and caulking as described above. You may comprise so that caulking fixing and an adhesive may be used together.

On the other hand, as shown in FIG. 4, both ends of the heating coil 12 are bent at substantially right angles, and the bent portions are terminal portions 24 and 25. These terminal portions 24,
Reference numeral 25 penetrates the printed wiring board 20 and protrudes to the lower surface side thereof, and is connected to one end of each of lead wires 26 and 27 made of, for example, a litz wire. The other ends of these lead wires 26 and 27 are connected to output terminals of the inverter circuit 13 (both terminals of the resonance capacitor 17).

On the lower surface of the printed wiring board 20,
The shielding conductor pattern 28 having a shape as shown in FIG. 5 is formed by, for example, printing. The shielding conductor pattern 28 is configured to absorb and shield leakage magnetic flux generated from the heating coil 12. In this case, the shielding conductor pattern 28 includes a plurality of relatively elongated conductor patterns 2.
9 are arranged radially from the center of the printed wiring board 20. This is because by forming each conductor pattern 29 in an elongated shape, it becomes difficult to flow an eddy current induced by receiving a leakage magnetic flux from the heating coil 12, thereby minimizing the generation of Joule heat. is there. As a result, each conductor pattern 29 of the shielding conductor pattern 28 is prevented from generating heat by induction heating as much as possible.

According to this embodiment having such a configuration, the heating coil 1 is formed by forming the strip-shaped copper plate 21 in a spiral shape.
Since the configuration 2 is used, the configuration is greatly simplified and the manufacturing cost is significantly reduced as compared with the conventional configuration using the litz wire 3 (see FIG. 9). Therefore, the configuration of the entire induction heating device 11 is simplified, the manufacturing cost is reduced, and the time required for assembly and manufacturing can be significantly reduced. And since the shape of the heating coil 12 becomes thin, the structure of the induction heating device 11 as a whole also becomes thin, and the whole becomes a thin and compact structure.

Further, since the shielding conductor pattern 28 for shielding the leakage magnetic flux generated from the heating coil 12 is provided on the lower surface of the printed wiring board 20, compared with the conventional configuration in which several ferrite rods are provided, For example, since only the printing molding is performed, the configuration for shielding the leakage magnetic flux is greatly simplified, the number of parts is reduced, and the manufacturing workability of the induction heating device 11 can be greatly improved. In this case, the shielding conductor pattern 28 is configured to have a shape in which eddy current is unlikely to flow. Specifically, a plurality of elongated conductor patterns 29 are provided to form the shielding conductor pattern 28. The eddy current induced in the conductor pattern 29 by receiving the magnetic flux becomes difficult to flow,
Generation of Joule heat is minimized. Thereby, it is possible to prevent each conductor pattern 29 of the shielding conductor pattern 28 from generating heat by induction heating as much as possible.

Further, in the above embodiment, when the shielding conductor pattern 28 is formed into a shape in which eddy current is unlikely to flow, the shielding conductor pattern 28 is formed into a shape as shown in FIG. 5. However, the present invention is not limited to this. It may be configured as in the second and third embodiments of the present invention shown in FIGS. 7 and 8, respectively.
In the second embodiment shown in FIG.
The shielding conductor pattern 31 is formed by arranging a large number of zeros. In the third embodiment shown in FIG. 8, a plurality of elongated strip-shaped conductor patterns 32 are arranged in parallel to form a shielding conductor pattern 33. The configuration of the second and third embodiments other than the above-described points is the same as the configuration of the first embodiment. Therefore, in the second and third embodiments, substantially the same operation and effect as those in the first embodiment can be obtained.

[0016]

According to the present invention, as is apparent from the above description, a heating coil is formed by forming a strip-shaped copper plate in a spiral shape, and the heating coil is mounted on the upper surface of the substrate. Eventually, the overall configuration of the induction heating device can be greatly simplified, the manufacturing cost can be greatly reduced, and
An excellent effect that the entire configuration can be made thin can be achieved. In this case, if a shielding conductor pattern for shielding the leakage magnetic flux generated from the heating coil is provided on the lower surface of the substrate, and if the shape of the shielding conductor pattern is configured to be a shape in which eddy current hardly flows, the leakage magnetic flux is shielded. Can be greatly simplified, the number of parts can be reduced, and the production workability of the induction heating device can be improved.

[Brief description of the drawings]

FIG. 1 is a top view of an induction heating apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial longitudinal sectional view of an induction heating device.

FIG. 3 is a partial longitudinal sectional view of different portions of the induction heating device.

FIG. 4 is a partial side view of the induction heating device.

FIG. 5 is a bottom view of the induction heating device.

FIG. 6 is an electric circuit diagram of the electromagnetic cooker.

FIG. 7 is a view corresponding to FIG. 5, showing a second embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 5, showing a third embodiment of the present invention.

FIG. 9 is a perspective view of an induction heating device showing a conventional configuration.

[Explanation of symbols]

11 is an induction heating device, 12 is a heating coil, 13 is an inverter circuit, 19 is a control circuit, 20 is a printed circuit board (substrate), 21 is a copper plate, and 28, 31, and 33 are shielding conductor patterns.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-99296 (JP, A) JP-A-4-337606 (JP, A) JP-A-1-120789 (JP, A) JP-A 55-99 124981 (JP, A) JP-A-5-82252 (JP, A) JP-A 63-79093 (JP, U) JP-A 50-82046 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 6/12

Claims (1)

(57) [Claims] 1. A induction heating apparatus of an electromagnetic cooker for induction heating a heated body such as a pot, a substrate, a heating coil a strip-shaped copper plate mounted on the upper surface of the substrate formed by spirally formed, wherein It is provided on the lower surface of the substrate and is generated from the heating coil.
Shape that shields the leakage magnetic flux from flowing, making it difficult for eddy currents to flow.
An induction heating device for an electromagnetic cooker , comprising: a shielding conductor pattern configured in a shape .