Matsushita Electric Industrial Co., Ltd.

Nobuyoshi Makio

Akira Kataoka

Katsuyuki Aihara

Izuo Hirota

Yuji Fujii

Takahiro Miyauchi

Toshihiro Keishima

Atsushi Fujita

Kazuya Gotou

An induction heating apparatus wherein an electrostatic shield and the low-potential portion of an inverter circuit are electrically connected securely is provided. The induction heating apparatus in accordance with the present invention comprises a top plateon which a matterto be heated is placed, an induction heating coilfor induction heating the matterto be heated, driving meansfor driving the induction heating coil, and a stationary plateand a cover for stationary plateprovided between the matterto be heated and the induction heating coil, wherein connection portionseach integrated with a connection terminalare electrically connected to the electrostatic shieldprovided on the stationary plateusing a conductive adhesive, and the connection parts are held between the stationary plateand the cover for stationary plate. With this configuration, the connection parts can be held securely and stably.

Induction heating apparatus

An induction heating apparatus with high safety is provided in which leakage current is prevented from flowing to the human body and there is no possibility of an electric shock even when an electrostatic shielding member does not sufficiently perform its function. The driving apparatus of the present invention is an induction heating apparatus in which the electrostatic shielding member is provided between an object to be heated and an induction heating coil where sensing portion for sensing the conduction condition of the electrostatic shielding member is provided, and driving portion for driving the induction heating coil is controlled through sensing by the sensing portion.

Induction heating apparatus having electrostatic shielding member

An induction heating coil having little high-frequency loss and producing little hast is easily manufactured by covering a conductor with a first insulating material to form a wire, then bundling and twisting such wires to form a stranded wire, covering the outer surface of the stranded wire with a second insulating material to form a coil wire, winding the coil wire a certain number of turns into a coil portion having a certain shape. The end portion of the coil portion and a connecting portion are heated with Joule heat while applying pressure to the end portion at the same time, so that the first and second insulating materials are fused and pressure-bonded to the conductor. Thus a terminal portion for the external connection of the coil portion is fixed while keeping the electrical connection with the conductor. Accordingly, an induction heating coil of low cost and stable quality can be easily manufactured. The induction heating coil producing little heat because of its high-frequency loss and suitable for induction heating of a highly-conductive nonmagnetic substance such as aluminum.

Induction heating coil

In an induction heating apparatus, in order to decrease the buoyancy exerted on an object to be heated which is made of a material having high electrical conductivity and low magnetic permeability, such as aluminum, an electrical conductor is provided between a heating coil and the object to be heated, thereby increasing the equivalent series resistance of the heating coil. Hence, the current of the heating coil, which is required for obtaining a desired heating output, is decreased, whereby the buoyancy of the object to be heated can be decreased. In addition, the electrical conductor is divided into two halves, and they are arranged in a circular arc form with a clearance provided therebetween and made close contact with the bottom face of a plate, whereby the temperature rise of the electrical conductor can be restricted. Furthermore, the heat of the electrical conductor is transferred and dissipated to the object to be heated, whereby the heating coil and the like are not damaged even if the electrical conductor is heated. An electrical conductor temperature sensor for detecting the temperature of the electrical conductor is provided; when the detection temperature becomes a predetermined temperature, the heating output of a drive circuit is decreased, whereby the heat generation of the electrical conductor is decreased and the heating coil and the like are not damaged by heat.

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Miki, Japan

Nobuyoshi Makio