JPH0612701B2 - Induction heating cooker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an induction heating cooker in which a control circuit is driven by using a coupling coil.

BACKGROUND ART Generally, in order to drive a semiconductor control circuit inside an induction heating cooker, a power transformer for converting a household 100V power supply to a low voltage is required, but the body is downsized, the weight is reduced, and the cost is reduced. In order to achieve this, a power supply method based on a coupling coil method, which uses high frequency of induction heating cost instead of a power transformer, has been adopted.

As one method of feeding by the coupling coil, there is a method in which the coupling coil 2 is diagonally positioned around the lower portion of the induction heating coil 1 as shown in FIG.

However, in the conventional configuration, firstly, if the positional relationship with the induction heating coil 1 varies, a predetermined output cannot be obtained, so that the coupling coil 2 must be securely fixed. It was very difficult to attach it to the back surface of the induction heating coil because it was necessary to bond it or to provide the fixture 3. Secondly, if the lead wire 5 connecting the coupling coil 2 to the control circuit 4 is poorly routed, it is affected by the high frequency magnetic field of the induction heating coil 1 to generate a noise component, which causes abnormal voltage generation. It was In particular, when the thickness of the body is reduced, it has been a serious problem if the induction heating coil 1 cannot be sufficiently separated.

Therefore, the present invention solves the above-mentioned problems, and provides an induction heating cooker having a coupling coil that can perform a reliable operation and is easy to install.

Means for Solving the Problems According to the present invention, a coupling coil is attached to a printed circuit board that constitutes a control circuit, and the coupling coil is arranged on the printed circuit board so that the coupling coil is located at a predetermined position of the induction heating coil. The lead wire to is abolished and is connected by the conductor surface of the printed circuit board.

Action With the above configuration, the attachment of the coupling coil becomes very easy and the positional relationship becomes reliable. In addition, since the connection between the coupling coil and the control circuit is a conductor on the printed circuit board, there is no variation in lead wiring and the noise influence can be included in the design condition in advance, so that an abnormal voltage is not generated.

Embodiment One embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In the figure, 6 is the main body of the electromagnetic cooker, 7 is the cooking plate, and 8
Is an induction heating coil, 9 is a control circuit board, and a coupling coil 10 is mounted on the upper surface thereof. The coupling coil 10 is located at a position in contact with the back surface of the supporting plate 11 of the induction heating coil 8 so that the coupling coil 10 has a constant distance from the induction heating coil 8. The coupling coil 10 is formed by winding the winding 12 around a coil bobbin 14 having a ferrite core 13 inside, and is fixed to the control circuit board 9 by soldering with the leg pins 15. 16 is a control circuit unit 17
Is a conductor film (copper foil) of a printed circuit board for connecting the coupling coil 10 with the coupling coil 10.

The operation of the coupling coil 10 having the above configuration will be described. When the power supply is turned on, the control circuit 17 and the inverter circuit 18 are activated, and a high-frequency current flows in the induction heating coil 8, a current is induced in the coupling coil 10 by the electromagnetic induction action, and the leg pin 15 and the conductor film of the substrate. It flows to the control circuit unit 17 through 16 (copper foil). The current I _P supplied to the control circuit unit 17 serves as a power source for the control circuit unit 17 thereafter. The power required for the initial activation until the current I _P of the coupling coil 10 flows is supplied from the switching regulator inside the control circuit unit 17.

At this time, the coupling coil current I _P is _equal to the induction heating coil 8
There is a possibility that the output may change due to the positional relationship between the conductor film 15 and the induction heating coil 8, or the positional relationship between the conductor film 15 and the induction heating coil 8.
Since the coupling coil 10 is arranged on the printed circuit board as in the present embodiment, the positional relationship becomes very accurate, and it is possible to suppress the occurrence of output variation and abnormal voltage to a very small level. Further, the coupling coil 16 itself can be attached only by inserting the leg pin 15 into a predetermined position of the control circuit board 9 and soldering it, which is very easy as compared with the conventional method attached to the induction heating coil 8 side. Has become.

EFFECTS OF THE INVENTION As is apparent from the description of the embodiments above, according to the present invention, the coupling coil is directly mounted on the printed circuit board forming the control circuit, and the lead wire is eliminated to form an integrated structure. Eliminates variations in the distance from the induction heating coil and placement position, suppresses output variations, suppresses abnormal voltage generation on the conductor system path from the coupling coil to the control circuit, and improves mounting work of the coupling coil itself. Can be planned.

[Brief description of drawings]

FIG. 1 is a sectional view of an induction heating cooker according to an embodiment of the present invention, FIG. 2 is a plan view of the same main part, FIG. 3 is a perspective view of the same main part, FIG. 4 is a control circuit diagram, and FIG. The figure is a sectional view of a conventional induction heating cooker. 8 ... Induction heating coil, 9 ... Control circuit board, 10 ...
Coupling coil.

Claims (1)

[Claims] 1. An induction heating coil, a coupling coil for supplying a drive current to a control circuit unit by utilizing a high frequency magnetic field generated by the induction heating coil, and a control circuit unit for controlling an oscillation frequency of the induction heating coil. The induction heating cooker, wherein the coupling coil is mounted on a printed circuit board that constitutes the control circuit unit so as to face the induction heating coil and is connected to a conductor of the printed circuit board.