JP2005078960A5

JP2005078960A5 -

Info

Publication number: JP2005078960A5
Application number: JP2003308538A
Authority: JP
Filing date: 2003-09-01
Publication date: 2007-08-30
Anticipated expiration: 2023-09-01

Description

Induction heating device

本発明は、高周波磁界による誘導加熱を利用して被加熱物の加熱を行う電磁調理器などの誘導加熱装置に関するものである。 The present invention relates to an induction heating device such as an electromagnetic cooker that heats an object to be heated by using induction heating by a high frequency magnetic field.

従来の誘導加熱装置において、加熱コイルの漏洩磁界低減した誘導加熱装置（例えば、特許文献１参照）について図面を用いて説明する。図８は、加熱コイルの漏洩磁界を低減した従来の誘導加熱装置である。本従来例では、加熱コイル１の外周部に電磁シールド環２を配置し、誘導加熱装置を構成している。この構成の誘導加熱装置では、加熱コイル１で生じた高周波磁界に誘導され電磁シールド環２に誘導電流が流れ、更にこの誘導電流により、電磁シールド環２には加熱コイル１から発生する高周波磁界とは逆向きの高周波磁界が発生する。この結果、電磁シールド環２から発生する高周波磁界が、加熱コイル１の外周部に発生する高周波磁界を打ち消す様に作用するため、加熱コイル１から漏洩する２０ｋ〜５０ｋＨｚ高周波漏洩磁界が減少する。なお、電磁シールド環２はアルミ板やリード線などを環状にしたものが知られている。 In a conventional induction heating apparatus, an induction heating apparatus (for example, see Patent Document 1) in which a leakage magnetic field of a heating coil is reduced will be described with reference to the drawings. FIG. 8 shows a conventional induction heating apparatus in which the leakage magnetic field of the heating coil is reduced. In this conventional example, an electromagnetic shield ring 2 is arranged on the outer peripheral portion of the heating coil 1 to constitute an induction heating device. In the induction heating apparatus having this configuration, an induction current flows through the electromagnetic shield ring 2 by being induced by the high-frequency magnetic field generated in the heating coil 1, and further, the induction current causes a high-frequency magnetic field generated from the heating coil 1 to be generated in the electromagnetic shield ring 2. Produces a reverse high-frequency magnetic field. As a result, the high-frequency magnetic field generated from the electromagnetic shield ring 2 acts so as to cancel out the high-frequency magnetic field generated on the outer peripheral portion of the heating coil 1, so that the 20 k to 50 kHz high-frequency leakage magnetic field leaking from the heating coil 1 is reduced. The electromagnetic shield ring 2 is known to have an aluminum plate, a lead wire or the like made into a ring.

他の加熱コイルから発生する漏洩磁界を低減する誘導加熱装置（例えば、特許文献２参照）について説明する。図９は従来の漏洩磁界を低減した誘導加熱装置である。加熱コイル１の外周近傍に巻き線を施してインダクタンス５を構成するとともに、加熱コイル１から発生する高周波磁界と、インダクタンス５が発生する高周波磁界成分が互いに打ち消す方向に配置している。図１０に従来の誘導加熱装置の回路例を示す。図１０の誘導加熱装置は商用電源などで構成される電源部３と電源部３の電力を高周波電力に変換する高周波発振部１１と高周波発振部１１の電力を高周波磁界に変換する加熱コイル１と加熱コイル１からの磁界を受けて発熱する負荷１５で構成されており、高周波発振部１１は、商用電源を整流する整流手段４と整流手段４の出力を平滑化するインダクタ５及び平滑コンデンサ６と加熱コイル１への電力供給を制御する半導体スイッチ８及び半導体スイッチ８のスイッチング動作を滑らかにする共振コンデンサ７から構成されている。図１０の従来例ではインダクタ５を巻き線のみで構成していおり、インダクタンス５のコア材を不要とし装置の小型化を図るとともに高周波ノイズの低減効果を併せ持っている。
特開昭５７−１１５７９５号公報特公昭６３−７６７２号公報 An induction heating apparatus (see, for example, Patent Document 2) that reduces a leakage magnetic field generated from another heating coil will be described. FIG. 9 shows a conventional induction heating apparatus with a reduced leakage magnetic field. The inductance 5 is formed by winding the vicinity of the outer periphery of the heating coil 1, and the high-frequency magnetic field generated from the heating coil 1 and the high-frequency magnetic field component generated by the inductance 5 are arranged to cancel each other. FIG. 10 shows a circuit example of a conventional induction heating apparatus. The induction heating apparatus of FIG. 10 includes a power supply unit 3 configured by a commercial power source, a high-frequency oscillation unit 11 that converts power from the power supply unit 3 into high-frequency power, and a heating coil 1 that converts power from the high-frequency oscillation unit 11 into a high-frequency magnetic field. The high frequency oscillating unit 11 includes a rectifier 4 that rectifies the commercial power supply, an inductor 5 and a smoothing capacitor 6 that smooth the output of the rectifier 4, and a load 15 that generates heat upon receiving a magnetic field from the heating coil 1. The semiconductor switch 8 that controls the power supply to the heating coil 1 and the resonance capacitor 7 that smoothes the switching operation of the semiconductor switch 8 are configured. In the conventional example shown in FIG. 10, the inductor 5 is composed only of windings, which eliminates the need for the core material of the inductance 5, thereby reducing the size of the device and simultaneously reducing the high frequency noise.
JP-A-57-115795 Japanese Patent Publication No. 63-7672

しかし、図８の様な従来の加熱コイルからの漏洩磁界を低減した誘導加熱装置においては、高周波の漏洩磁界は電磁シールド環２の効果により、減少させることができるが、加熱コイル１から発生する電源周波数または電源の２倍周波数の磁界（以下低周波磁界）は、電磁シールド環２では抑制できないので負荷１５にほとんど吸収されず外部に放出され、また電磁シールド環２は逆向きの磁界を十分発生させないので、低周波磁界が減少しない。 However, in the induction heating apparatus in which the leakage magnetic field from the conventional heating coil as shown in FIG. 8 is reduced, the high-frequency leakage magnetic field can be reduced by the effect of the electromagnetic shield ring 2 but is generated from the heating coil 1. A magnetic field having a power source frequency or twice the frequency of the power source (hereinafter referred to as a low-frequency magnetic field) cannot be suppressed by the electromagnetic shield ring 2 and is therefore hardly absorbed by the load 15 and released to the outside. The electromagnetic shield ring 2 has a sufficient reverse magnetic field. Since it is not generated, the low frequency magnetic field does not decrease.

一方、図９の従来の誘導加熱装置においては、巻き線をインダクタンスとして動作させるため（数１００μＨ程度）、巻き線の巻き数が多くなることになる。この際、巻き線から放出される低周波磁界が加熱コイルから放出される低周波磁界より大きくなり、外部に放出する低周波磁界が増加する課題が生じることになる。また、従来の誘導加熱装置は高周波磁界を打ち消すことを目的としており、漏洩磁界低減用の巻き線は加熱コイルの最外周部の外側に限定され、配置の自由度がないという課題が生じることになる。 On the other hand, in the conventional induction heating apparatus of FIG. 9, since the winding is operated as an inductance (about several hundred μH), the number of turns of the winding increases. At this time, the low-frequency magnetic field emitted from the winding becomes larger than the low-frequency magnetic field emitted from the heating coil, resulting in an increase in the low-frequency magnetic field emitted to the outside. Further, the conventional induction heating device aims to cancel the high-frequency magnetic field, and the winding for reducing the leakage magnetic field is limited to the outside of the outermost peripheral portion of the heating coil, resulting in the problem that there is no degree of freedom in arrangement. Become.

また、上記の様に従来の誘導加熱装置は高周波の漏洩磁界を低減させるもので、低周波の漏洩磁界の低減に着目してこなかった。しかし、低周波漏洩磁界を低減することにより、因果関係は明確ではないが一部の調査で懸念されている低周波磁界の人体への影響に対する機器使用者の不安を取り除くことができ、また機器の極近傍の電子機器の誤動作のリスクを排除することもできる。 Further, as described above, the conventional induction heating apparatus reduces the high-frequency leakage magnetic field, and has not paid attention to the reduction of the low-frequency leakage magnetic field. However, by reducing the low-frequency leakage magnetic field, the user's anxiety about the effects on the human body of the low-frequency magnetic field, which is not clear in the causal relationship but is concerned in some investigations, can be removed. It is also possible to eliminate the risk of malfunction of an electronic device in the immediate vicinity of.

本発明は上記の課題を解決するべく従来の誘導加熱装置に対策されてきた高周波漏洩磁界に加え、今まで認知されなかった低周波漏洩磁界にも焦点をあて対策するもので、低周波磁界が加熱コイルから放射されることを減少させ、かつ高周波成分の漏れ磁界も両立して抑制し、機器から発生する不要な電磁波を減少させる誘導加熱装置を提供することを目的としている。 The present invention focuses on low-frequency leakage magnetic fields that have not been recognized so far, in addition to high-frequency leakage magnetic fields that have been dealt with in conventional induction heating devices in order to solve the above-mentioned problems. An object of the present invention is to provide an induction heating device that reduces radiation emitted from a heating coil, suppresses a leakage magnetic field of high-frequency components and reduces unnecessary electromagnetic waves generated from the device.

上記課題を解決するために本発明は、電源部に接続され商用周波数の電力を整流し商用周波数の２倍の周波数の低周波成分を持った電力に変換する整流手段と、高周波磁界を発生し被加熱物を誘導加熱する加熱コイルと、前記低周波成分を持った電力を高周波電力に変換し前記加熱コイルに前記低周波成分と高周波成分が重畳した高周波電流を供給する高周波発振部と、環状の導体を前記加熱コイル外周部に配した電磁シールド環とを備え、前記高周波発振部内にあり前記低周波成分を持つ低周波電流が流れる配線を、前記加熱コイル近傍にコイル状に施しかつ前記配線より発生する低周波磁界と前記加熱コイルより発生する低周波磁界が互いに打ち消す方向となるように配置しさらに外部に漏洩する前記低周波磁界を低減するように１回または複数回巻いて構成した低周波磁界打ち消し手段を有するとともに、前記電磁シールド環は前記低周波打ち消し手段の外周部に配置する誘導加熱装置としている。 In order to solve the above problems, the present invention generates a high-frequency magnetic field and a rectifying means connected to a power supply unit for rectifying commercial frequency power and converting it to power having a low frequency component twice the commercial frequency. A heating coil for inductively heating an object to be heated; a high-frequency oscillation section for converting a power having the low-frequency component into a high-frequency power and supplying a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil; and a electromagnetic shield ring arranged on the heating coil outer periphery of the conductor, the high frequency is in the oscillating portion the wires that low-frequency current having a low frequency component flows, subjected to the heating coils near the coiled and the wire The low-frequency magnetic field generated from the heating coil and the low-frequency magnetic field generated from the heating coil are arranged so as to cancel each other, and further, the low-frequency magnetic field leaking outside is reduced once. Together with having a low frequency magnetic field cancellation means constituted by plurality of turns, the electromagnetic shield rings are an induction heating apparatus disposed in an outer peripheral portion of the low-frequency canceling means.

これにより、高周波発振部内にあり前記加熱コイルに流れる電流の低周波成分と同じ周波数成分で前記加熱コイルと逆向きに電流が流れるように配置した低周波磁界打ち消し手段が、加熱コイルから発生する低周波漏洩磁界を大きく低減させるとともに、電磁シールド環を低周波磁界打ち消し手段の外周部に配置することで、更に低周波から高周波にわたり漏洩磁界を減少させることができるため、漏洩磁界の少ない誘導加熱装置を実現するものである。 Accordingly, the low-frequency magnetic field canceling means arranged in the high-frequency oscillating portion so that the current flows in the opposite direction to the heating coil with the same frequency component as the low-frequency component of the current flowing through the heating coil is generated by the low-frequency generated from the heating coil. Induction heating device with less leakage magnetic field because the leakage magnetic field can be further reduced from low to high frequency by greatly reducing the frequency leakage magnetic field and arranging the electromagnetic shield ring on the outer periphery of the low frequency magnetic field canceling means. Is realized.

以上のように請求項１〜５記載の本発明によれば、高周波発振部内にあり前記加熱コイルに流れる電流の低周波成分と同じ周波数成分で前記加熱コイルと逆向きに電流が流れるように配置した低周波磁界打ち消し手段が、加熱コイルから発生する低周波漏洩磁界を大きく低減させるとともに、電磁シールド環を低周波磁界打ち消し手段の外周部に配置することで、更に低周波から高周波にわたり漏洩磁界を減少させることができるため、漏洩磁界の少ない誘導加熱装置を実現するものである。 As described above, according to the first to fifth aspects of the present invention, the current flows in the direction opposite to the heating coil at the same frequency component as the low frequency component of the current flowing in the heating coil in the high-frequency oscillation unit. The low-frequency magnetic field canceling means greatly reduces the low-frequency leakage magnetic field generated from the heating coil, and the electromagnetic shield ring is arranged on the outer periphery of the low-frequency magnetic field canceling means, thereby further reducing the leakage magnetic field from low to high frequencies. Since it can be reduced, an induction heating device with a small leakage magnetic field is realized.

請求項１に係わる本発明は、電源部に接続され商用周波数の電力を整流し商用周波数の２倍の周波数の低周波成分を持った電力に変換する整流手段と、高周波磁界を発生し被加熱物を誘導加熱する加熱コイルと、前記低周波成分を持った電力を高周波電力に変換し前記加熱コイルに前記低周波成分と高周波成分が重畳した高周波電流を供給する高周波発振部と、環状の導体を前記加熱コイル外周部に配した電磁シールド環とを備え、前記高周波発振部内にあり前記低周波成分を持つ低周波電流が流れる配線を、前記加熱コイル近傍にコイル状に施しかつ前記配線より発生する低周波磁界と前記加熱コイルより発生する低周波磁界が互いに打ち消す方向となるように配置しさらに外部に漏洩する前記低周波磁界を低減するように１回または複数回巻いて構成した低周波磁界打ち消し手段を有するとともに、前記電磁シールド環は前記低周波打ち消し手段の外周部に配置する誘導加熱装置としている。 The present invention according to claim 1 is a rectifier that is connected to a power supply unit and rectifies power at a commercial frequency to convert it into power having a low frequency component twice the commercial frequency, and generates a high frequency magnetic field to be heated. A heating coil for inductively heating an object, a high-frequency oscillation unit for converting a power having the low-frequency component into a high-frequency power and supplying a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil, and an annular conductor the an electromagnetic shield ring arranged on the heating coil outer periphery, the high frequency is in the oscillating portion the wires that low-frequency current having a low frequency component flows, subjected to the heating coils near coiled and generated by the wiring The low frequency magnetic field and the low frequency magnetic field generated by the heating coil are arranged so as to cancel each other, and further, the low frequency magnetic field leaking to the outside is reduced once or plural times. Together with a low-frequency magnetic field cancellation means configured by winding, the electromagnetic shield rings are an induction heating apparatus disposed in an outer peripheral portion of the low-frequency canceling means.

請求項２に係わる発明は、上記に加え、電磁シールド環はリード線を環状にして構成し、低周波磁界打ち消し手段はリード線をコイル状に構成した誘導加熱装置としている。 In addition to the above, the invention according to claim 2 is an induction heating apparatus in which the electromagnetic shield ring is formed by making the lead wire into an annular shape, and the low frequency magnetic field canceling means is formed by forming the lead wire in a coil shape.

これにより、加熱コイルの外周部近傍に、低周波磁界打ち消し手段と電磁シールド環を近接して配置することができるため、低周波磁界打ち消し手段及び電磁シールド環が誘導加熱装置の形状に大きく影響を与えることなく配置することができ、従来の形状を保ったまま漏洩磁界を低減することができる誘導加熱装置を実現するものである。 As a result, the low-frequency magnetic field canceling means and the electromagnetic shield ring can be arranged close to the outer periphery of the heating coil, so that the low-frequency magnetic field canceling means and the electromagnetic shield ring greatly affect the shape of the induction heating device. It is possible to realize an induction heating device that can be arranged without giving, and can reduce a leakage magnetic field while maintaining a conventional shape.

請求項３に係わる発明は、上記に加え、電磁シールド環の外側に磁性体を配置した誘導加熱装置としている。 In addition to the above, the invention according to claim 3 is an induction heating device in which a magnetic material is disposed outside the electromagnetic shield ring.

これにより、低周波磁界打ち消し手段及び電磁シールド環を用いて抑制できなかった漏洩磁界を磁性体に吸収させることで、周波数によらず漏洩磁界を更に低減させることができ、より漏洩磁界の少ない誘導加熱装置を実現できるものである。 As a result, the leakage magnetic field that could not be suppressed using the low-frequency magnetic field canceling means and the electromagnetic shield ring is absorbed by the magnetic material, so that the leakage magnetic field can be further reduced regardless of the frequency, and the induction with less leakage magnetic field can be achieved. A heating device can be realized.

請求項４に係わる発明は、上記に加え、２線を一体化したケーブルをコイル状に形成し、２線のうちの一方の線を低周波磁界打ち消し手段とし、他方は周回部で短絡して環状に結線し電磁シールド環とした誘導加熱装置としている。 In the invention according to claim 4, in addition to the above, a cable in which two wires are integrated is formed in a coil shape, one of the two wires is used as a low-frequency magnetic field canceling means, and the other is short-circuited at the circuit portion. It is an induction heating device that is connected in an annular shape to form an electromagnetic shield ring.

これにより、低周波磁界打ち消し手段と電磁シールド環を一体化された１組の線を巻くことで構成することができるため、従来の誘導加熱装置からあまり形状を変えることなく、しかも低周波打ち消し手段と電磁シールド環を同時に扱えるため組み立て作業性が良く、簡易な構成で漏洩磁界を低減できる誘導加熱装置を実現できるものである。 As a result, the low frequency magnetic field canceling means and the electromagnetic shield ring can be formed by winding a pair of wires, so that the shape is not changed so much from the conventional induction heating device, and the low frequency canceling means Since the electromagnetic shield ring can be handled at the same time, the assembly workability is good, and an induction heating device that can reduce the leakage magnetic field with a simple configuration can be realized.

請求項５に係わる発明は、上記に加え、シールドケーブルの信号線をコイル状に形成し、シールドケーブルの軸側の電線を低周波磁界打ち消し手段とし、シールド線側の電線は周回部で短絡して環状に結線し電磁シールド環とした誘導加熱装置としている。 In addition to the above, the invention according to claim 5 is configured such that the signal wire of the shield cable is formed in a coil shape, the electric wire on the shaft side of the shield cable is used as a low-frequency magnetic field canceling means, and the electric wire on the shield wire side is short-circuited at the circuit portion. Thus, the induction heating device is connected in a ring to form an electromagnetic shield ring.

（実施例１）
本発明の第１の実施例について図面を参照しながら説明する。本実施例は請求項１に係わる。 (Example 1)
A first embodiment of the present invention will be described with reference to the drawings. This embodiment relates to claim 1.

図１は本実施例の誘導加熱装置の構成を示す図である。商用電源を含む電源部３は、高周波発振部１１に接続され、高周波発振部１１は加熱コイル１に接続される。加熱コイル１は上部に鍋などの負荷１５が加熱コイル１と磁気結合する形で設置され、下部には負荷１５との磁気結合を高める防磁フェライト１３が配置される。また、高周波発振部１１は電源部３に接続される整流手段４と、整流手段４と直列に接続されるインダクタ５と平滑コンデンサ６の直列接続と、平滑コンデンサ６に並列に接続される共振コンデンサ７と半導体スイッチ８の直列接続からなり、共振コンデンサ７は加熱コイル１と並列に接続される。一方、インダクタ５の配線は加熱コイルの外周部近傍でフェライトの下部に加熱コイル１の巻き方向とは逆に複数回巻かれ、低周波打ち消し手段を構成する。更に低周波打ち消し手段１２とほぼ同じ箇所または低周波打ち消し手段１２の外周部には、電磁シールド環２が配置される。この配置の一例を図２に示す。電磁シールド環２は、導電性の金属で表皮抵抗が小さいアルミなどが望ましく、アルミリングなどが使われる。 FIG. 1 is a diagram showing the configuration of the induction heating apparatus of this embodiment. The power supply unit 3 including a commercial power supply is connected to the high frequency oscillation unit 11, and the high frequency oscillation unit 11 is connected to the heating coil 1. The heating coil 1 is installed at the upper part in such a manner that a load 15 such as a pan is magnetically coupled to the heating coil 1, and a magnetic shield ferrite 13 is arranged at the lower part to enhance the magnetic coupling with the load 15. The high-frequency oscillation unit 11 includes a rectifying unit 4 connected to the power source unit 3, a series connection of an inductor 5 and a smoothing capacitor 6 connected in series with the rectifying unit 4, and a resonant capacitor connected in parallel to the smoothing capacitor 6. 7 and the semiconductor switch 8 are connected in series, and the resonant capacitor 7 is connected in parallel with the heating coil 1. On the other hand, the wiring of the inductor 5 is wound a plurality of times in the vicinity of the outer periphery of the heating coil around the lower part of the ferrite in the direction opposite to the winding direction of the heating coil 1 to constitute a low-frequency canceling means. Further, the electromagnetic shield ring 2 is arranged at substantially the same location as the low frequency canceling means 12 or at the outer periphery of the low frequency canceling means 12. An example of this arrangement is shown in FIG. The electromagnetic shield ring 2 is preferably made of an electrically conductive metal such as aluminum having a low skin resistance, and an aluminum ring or the like is used.

本実施例では、誘導加熱装置に用いられる一般的な回路構成を示しているが、加熱コイル１に低周波磁界成分が重畳する回路構成であれば特に限定するものではない。 In this embodiment, a general circuit configuration used for the induction heating apparatus is shown, but there is no particular limitation as long as the circuit configuration is such that a low-frequency magnetic field component is superimposed on the heating coil 1.

次に本実施例に動作に関して説明する。図３はインバータ回路の各区間における電流経路を示した図である。Ｉ３は入力電流を、Ｉ５はインダクタ５及び低周波磁界打ち消し手段１２に流れる電流を、Ｉ１は加熱コイルに流れる電流を示している。電源部３は商用電源などで構成され、高周波発振部１１に商用周波数の電力を供給する。そのため、入力電流Ｉ３は、商用周波数成分を持つ電流になる。高周波発振部１１では整流手段４により商用電力を整流して商用電源の２倍の周波数成分を持った電力に変換し、更に半導体スイッチ８を用いて２０ｋ〜５０ｋＨｚ程度の高周波電力に変換される。そしてこの高周波電力は加熱コイル１に供給され、加熱コイル１から高周波磁界の形で負荷１５に供給される。負荷１５は、高周波磁界に従い表層部に渦電流が生じ、その結果発熱するに至る。そのため、インダクタ５及び低周波磁界打ち消し手段１２に流れる電流は商用周波数の２倍の周波数の電流Ｉ５が流れ、また加熱コイル１には半導体スイッチ８が導通状態になったときに電源部１→整流手段４→加熱コイル１→半導体スイッチ８のループで生じる商用周波数の２倍の成分をもつ低周波電流と、半導体スイッチ８の周波数に従って加熱コイル１に流れる高周波成分が重畳した電流Ｉ１１が流れる。よって加熱コイル１と低周波磁界打ち消し手段１２の低周波磁界が互いに打ち消すように配置することにより、加熱コイル１から発生する低周波磁界を打ち消すことができる。また、低周波磁界打ち消し手段１２は加熱コイル１が複数に分割されている場合などは外側に加熱コイル１の近傍に配置することが望ましく、また複数回巻いた方がより多くの打ち消し磁界を発生させることが可能になる。但し、低周波磁界打ち消し手段１２を複数回巻く場合においては、巻き数が多いと逆に低周波磁界打ち消し手段１２からの磁界が大きくなるため、加熱コイル１の巻き数の概１／２以下の巻き数で構成することになる。 Next, the operation of this embodiment will be described. FIG. 3 is a diagram showing a current path in each section of the inverter circuit. I3 is an input current, I5 is a current flowing through the inductor 5 and the low-frequency magnetic field canceling means 12, and I1 is a current flowing through the heating coil. The power supply unit 3 is composed of a commercial power source or the like, and supplies commercial frequency power to the high-frequency oscillation unit 11. Therefore, the input current I3 is a current having a commercial frequency component. In the high-frequency oscillating unit 11, the commercial power is rectified by the rectifying means 4 to be converted into power having a frequency component twice that of the commercial power supply, and further converted into high-frequency power of about 20 k to 50 kHz using the semiconductor switch 8. This high frequency power is supplied to the heating coil 1 and supplied from the heating coil 1 to the load 15 in the form of a high frequency magnetic field. The load 15 generates an eddy current in the surface layer portion according to the high-frequency magnetic field, and as a result, generates heat. For this reason, the current I5 having a frequency twice the commercial frequency flows through the inductor 5 and the low-frequency magnetic field canceling means 12, and when the semiconductor switch 8 becomes conductive in the heating coil 1, the power source 1 → rectifier A current I11 in which a low-frequency current having a component twice the commercial frequency generated in the loop of means 4 → heating coil 1 → semiconductor switch 8 and a high-frequency component flowing in the heating coil 1 according to the frequency of the semiconductor switch 8 flows. Therefore, the low frequency magnetic field generated from the heating coil 1 can be canceled by arranging the heating coil 1 and the low frequency magnetic field canceling means 12 so that the low frequency magnetic fields cancel each other. Further, the low frequency magnetic field canceling means 12 is preferably arranged outside the heating coil 1 when the heating coil 1 is divided into a plurality of parts, and more canceling magnetic fields are generated by winding a plurality of times. It becomes possible to make it. However, when the low-frequency magnetic field canceling means 12 is wound a plurality of times, the magnetic field from the low-frequency magnetic field canceling means 12 increases conversely when the number of turns is large, and therefore the number of turns of the heating coil 1 is approximately ½ or less. It consists of the number of turns.

一方、加熱コイル１と負荷１５の間は通常１０ｍｍ前後の空隙が存在する。そのため、加熱コイル１から発生する高周波磁界の内負荷１５に吸収されずに外部に放出される漏れ磁界が存在する。この漏れ磁界は外周部ほど多くなるため、最外部に周辺に逆向きの高周波磁界を発生させる方法が有効である。しかし、低周波漏れ磁界低減手段１２から発生する磁界は、低周波が大部分で高周波漏れ磁界の低減効果は少ない。そこで、加熱コイル１の外周部に電磁シールド環２を配置することで、加熱コイル１に対する打ち消し磁界を電磁シールド環２に発生させ、高周波漏れ磁界を低減させることができる。この際、高周波漏れ磁束への影響が少ない低周波漏れ磁界低減手段１２を加熱コイル１の外側の下方向に配置し、電磁シールド環２を加熱コイル１の外周部に配置することで、設置スペースを取らずまた、高周波磁界の分布を大きく乱すことなく漏れ磁界を低減することができる。 On the other hand, a gap of about 10 mm usually exists between the heating coil 1 and the load 15. For this reason, there is a leakage magnetic field that is not absorbed by the internal load 15 of the high-frequency magnetic field generated from the heating coil 1 and is released to the outside. Since this leakage magnetic field increases toward the outer periphery, it is effective to generate a high-frequency magnetic field in the opposite direction at the outermost part. However, the magnetic field generated from the low-frequency leakage magnetic field reduction means 12 is mostly low-frequency and the effect of reducing the high-frequency leakage magnetic field is small. Therefore, by disposing the electromagnetic shield ring 2 on the outer periphery of the heating coil 1, a canceling magnetic field for the heating coil 1 can be generated in the electromagnetic shield ring 2, and the high-frequency leakage magnetic field can be reduced. At this time, the low-frequency leakage magnetic field reduction means 12 having a small influence on the high-frequency leakage magnetic flux is arranged in the downward direction outside the heating coil 1, and the electromagnetic shield ring 2 is arranged on the outer peripheral portion of the heating coil 1, thereby providing an installation space. In addition, the leakage magnetic field can be reduced without significantly disturbing the distribution of the high-frequency magnetic field.

以上のように本実施例では、高周波発振部１１内にあり前記加熱コイル１に流れる電流の低周波成分と同じ周波数成分で前記加熱コイル１と逆向きに電流が流れるように配置した低周波磁界打ち消し手段１２が、加熱コイル１から発生する低周波漏洩磁界を大きく低減させるとともに、電磁シールド環２を低周波磁界打ち消し手段１２の外周部に配置することで、更に低周波から高周波にわたり漏洩磁界を減少させることができるため、漏洩磁界の少ない誘導加熱装置を実現するものである。 As described above, in this embodiment, the low frequency magnetic field is arranged in the high frequency oscillating unit 11 so that the current flows in the opposite direction to the heating coil 1 with the same frequency component as the low frequency component of the current flowing in the heating coil 1. The canceling means 12 greatly reduces the low-frequency leakage magnetic field generated from the heating coil 1, and the electromagnetic shield ring 2 is disposed on the outer periphery of the low-frequency magnetic field canceling means 12, thereby further reducing the leakage magnetic field from low to high frequencies. Since it can be reduced, an induction heating device with a small leakage magnetic field is realized.

（実施例２）
本発明の第２の実施例について図面を参照しながら説明する。本実施例は請求項２に係わる。 (Example 2)
A second embodiment of the present invention will be described with reference to the drawings. This embodiment relates to claim 2.

本実施例の構成を図４に示す。本実施例が実施例１と異なるのは、電磁シールド環を導線で構成している点である。 The configuration of this embodiment is shown in FIG. This embodiment is different from the first embodiment in that the electromagnetic shield ring is composed of a conducting wire.

上記構成における動作について説明する。本実施例では図４に示すように、電磁シールド環２を導線で構成している。導線はリング上にしたものを複数本用いる場合もある。電磁シールド環２を導線で構成することにより、金属板で構成するときよりも電磁シールド環２の配置の自由度があるため、誘導加熱装置の筐体を小さくすることができる。また、低周波磁界低減手段１２と電磁シールド環２を近接して配置することが可能になるため、両者を一つの治具で止めることができるなど簡易なシールド構成を取ることが可能になる。 The operation in the above configuration will be described. In this embodiment, as shown in FIG. 4, the electromagnetic shield ring 2 is constituted by a conductive wire. There may be a case where a plurality of conductors are used on a ring. By configuring the electromagnetic shield ring 2 with a conductive wire, there is a degree of freedom in arrangement of the electromagnetic shield ring 2 as compared with the case of configuring it with a metal plate, so that the casing of the induction heating device can be made smaller. In addition, since the low-frequency magnetic field reducing means 12 and the electromagnetic shield ring 2 can be arranged close to each other, it is possible to adopt a simple shield configuration in which both can be stopped with one jig.

以上の様に本実施例によれば、加熱コイル１の外周部近傍に、低周波磁界打ち消し手段１２と電磁シールド環２を近接して配置することができるため、低周波磁界打ち消し手段１２及び電磁シールド環２が誘導加熱装置の形状に大きく影響を与えることなく配置することができ、従来の形状を保ったまま漏洩磁界を低減することができる誘導加熱装置を実現するものである。 As described above, according to the present embodiment, the low-frequency magnetic field canceling means 12 and the electromagnetic shield ring 2 can be arranged close to each other in the vicinity of the outer peripheral portion of the heating coil 1. The shield ring 2 can be arranged without greatly affecting the shape of the induction heating device, and an induction heating device that can reduce the leakage magnetic field while maintaining the conventional shape is realized.

（実施例３）
本発明の第３の実施例について図面を参照しながら説明する。本実施例は請求項３に係わる。 (Example 3)
A third embodiment of the present invention will be described with reference to the drawings. This embodiment relates to claim 3.

本実施例の構成を図５に示す。本実施例が実施例１と異なるのは、電磁シールド環２の外周部に磁性体１４を配置している点である。 The configuration of this embodiment is shown in FIG. The present embodiment is different from the first embodiment in that a magnetic body 14 is disposed on the outer peripheral portion of the electromagnetic shield ring 2.

上記構成における動作について説明する。本実施例では図５に示すように、電磁シールド環２の外周部に磁性体１４が配置されている。そのため、磁性体１４が加熱コイル１からの漏れ磁束を吸収し、更に漏れ磁界を低減することができる。また、電磁シールド環２により大部分の磁界を打ち消しているため、磁性体１４自体の発熱も抑えられることになる。なお、磁性体１４としては、鉄、ステンレス及び珪素鋼板などがあり、特に限定するものではない。 The operation in the above configuration will be described. In this embodiment, as shown in FIG. 5, the magnetic body 14 is disposed on the outer periphery of the electromagnetic shield ring 2. Therefore, the magnetic body 14 can absorb the leakage magnetic flux from the heating coil 1 and further reduce the leakage magnetic field. In addition, since most of the magnetic field is canceled by the electromagnetic shield ring 2, heat generation of the magnetic body 14 itself can be suppressed. Examples of the magnetic body 14 include iron, stainless steel, and silicon steel plate, and are not particularly limited.

以上の様に本実施例によれば、低周波磁界打ち消し手段１２及び電磁シールド環２を用いて抑制できなかった漏洩磁界を磁性体１４に吸収させることで、周波数によらず漏洩磁界を更に低減させることができ、より漏洩磁界の少ない誘導加熱装置を実現できるものである。 As described above, according to the present embodiment, the leakage magnetic field that cannot be suppressed by using the low-frequency magnetic field canceling means 12 and the electromagnetic shield ring 2 is absorbed by the magnetic body 14, thereby further reducing the leakage magnetic field regardless of the frequency. Thus, an induction heating device with less leakage magnetic field can be realized.

（実施例４）
本発明の第４の実施例について図面を参照しながら説明する。本実施例は請求項４に係わる。 Example 4
A fourth embodiment of the present invention will be described with reference to the drawings. This embodiment relates to claim 4.

本実施例の構成を図６に示す。本実施例が実施例２と異なるのは、低周波磁界打ち消し手段１２及び電磁シールド環２を２線ケーブル１６で構成している点である。 The configuration of this embodiment is shown in FIG. This embodiment is different from the second embodiment in that the low-frequency magnetic field canceling means 12 and the electromagnetic shield ring 2 are configured by a two-wire cable 16.

本実施例の動作について説明する。本実施例では、２線ケーブル１６を加熱コイル１の近傍に１回もしくは複数回コイル状に巻き付ける。そして２線ケーブル１６は、１本を低周波磁界打ち消し手段１２として用いるため高周波発振部１１内にあり加熱コイル１の低周波成分と同じ成分をもつ配線と直列に接続され、残りの１本は電磁シールド環２として加熱コイル１を一周する毎に環状に短絡する構成をとる。このことにより、２線が加熱コイル１の近傍に簡易に配置することが可能になる。 The operation of this embodiment will be described. In this embodiment, the two-wire cable 16 is wound around the heating coil 1 once or a plurality of times in a coil shape. And since the two-wire cable 16 is used as the low-frequency magnetic field canceling means 12, the two-wire cable 16 is connected in series with the wiring having the same component as the low-frequency component of the heating coil 1 in the high-frequency oscillating unit 11, and the remaining one is The electromagnetic shield ring 2 is configured to be short-circuited in an annular shape every time the heating coil 1 goes around. This makes it possible to easily arrange the two wires in the vicinity of the heating coil 1.

以上の様に本実施例では、低周波磁界打ち消し手段１２と電磁シールド環２を一体化された１組の線を巻くことで構成することができるため、従来の誘導加熱装置からあまり形状を変えることなく、しかも低周波打ち消し手段１２と電磁シールド環２を同時に扱えるため作業性の良い構成をとることができ、簡易な構成で漏洩磁界を低減できる誘導加熱装置を実現できるものである。 As described above, in this embodiment, since the low frequency magnetic field canceling means 12 and the electromagnetic shield ring 2 can be formed by winding a set of integrated wires, the shape is changed so much from the conventional induction heating device. In addition, since the low-frequency canceling means 12 and the electromagnetic shield ring 2 can be handled at the same time, a configuration with good workability can be achieved, and an induction heating apparatus that can reduce the leakage magnetic field with a simple configuration can be realized.

（実施例５）
本発明の第５の実施例について図面を参照しながら説明する。本実施例は請求項５に係わる。 (Example 5)
A fifth embodiment of the present invention will be described with reference to the drawings. This embodiment relates to claim 5.

本実施例の構成を図７に示す。本実施例が実施例２と異なるのは、低周波磁界打ち消し手段１２及び電磁シールド環２をシールドケーブル１７で構成している点である。 The configuration of this embodiment is shown in FIG. This embodiment is different from the second embodiment in that the low-frequency magnetic field canceling means 12 and the electromagnetic shield ring 2 are configured by a shield cable 17.

本実施例の動作について説明する。本実施例では、シールドケーブル１７を加熱コイル１の近傍に１回もしくは複数回コイル状に巻き付ける。そしてシールドケーブル１７は、低周波磁界打ち消し手段１２として用いるため高周波発振部１１内にあり加熱コイル１の低周波成分と同じ成分をもつ配線と直列に接続さる。一方、シールド線は電磁シールド環２として用いるため加熱コイル１を一回りする毎に環状に短絡する。このことにより、低周波漏れ磁界及び高周波漏れ磁界対策用の対策を加熱コイル１の近傍に簡易に配置することが可能になる。 The operation of this embodiment will be described. In the present embodiment, the shield cable 17 is wound around the heating coil 1 once or a plurality of times in a coil shape. The shield cable 17 is used as the low-frequency magnetic field canceling means 12 and is connected in series with a wiring that is in the high-frequency oscillation unit 11 and has the same component as the low-frequency component of the heating coil 1. On the other hand, since the shield wire is used as the electromagnetic shield ring 2, the shield wire is short-circuited in an annular shape every time it goes around the heating coil 1. This makes it possible to easily dispose measures for countermeasures against low-frequency leakage magnetic fields and high-frequency leakage magnetic fields in the vicinity of the heating coil 1.

本発明の第１の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of 1st Example of this invention. 本発明の第１の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of 1st Example of this invention. 本発明の第１に実施例の誘導加熱装置の動作波形を示す図The figure which shows the operation | movement waveform of the induction heating apparatus of a 1st Example of this invention. 本発明の第２の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of 2nd Example of this invention. 本発明の第３の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of the 3rd Example of this invention. 本発明の第４の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of the 4th Example of this invention. 本発明の第５の実施例の誘導加熱装置の構成を示す図The figure which shows the structure of the induction heating apparatus of the 5th Example of this invention. 従来の誘導加熱装置の構成を示す図The figure which shows the structure of the conventional induction heating apparatus 従来の誘導加熱装置の構成を示す図The figure which shows the structure of the conventional induction heating apparatus 従来の誘導加熱加熱装置の回路構成を示す図The figure which shows the circuit structure of the conventional induction heating heating apparatus.

Explanation of symbols

１加熱コイル
２電磁シールド環
３電源部
４整流手段
５インダクタ
６平滑コンデンサ
７共振コンデンサ
８半導体スイッチ
１１高周波発振部
１２低周波磁界打ち消し手段
１３防磁フェライト
１４磁性体
１５負荷
１６２軸ケーブル
１７シールドケーブル DESCRIPTION OF SYMBOLS 1 Heating coil 2 Electromagnetic shield ring 3 Power supply part 4 Rectification means 5 Inductor 6 Smoothing capacitor 7 Resonance capacitor 8 Semiconductor switch 11 High frequency oscillation part 12 Low frequency magnetic field cancellation means 13 Magnetic shield ferrite 14 Magnetic body 15 Load 16 Biaxial cable 17 Shield cable

Claims

A rectifying means connected to the power supply unit for rectifying the power of the commercial frequency and converting it into a power having a low frequency component of a frequency twice the commercial frequency, a heating coil for generating a high frequency magnetic field and induction heating the object to be heated; A high-frequency oscillating unit that converts power having the low-frequency component into high-frequency power and supplies a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil, and an annular conductor is disposed on the outer periphery of the heating coil. and an electromagnetic shield ring, from the high frequency is in the oscillation portion the low-frequency wiring the low-frequency current flows having a component, said heating coil and the low-frequency magnetic field generated from the coiled subjected and the wiring in the vicinity the heating coil A low-frequency magnetic field which is arranged so that the generated low-frequency magnetic fields are in a direction to cancel each other, and is wound once or a plurality of times so as to reduce the low-frequency magnetic field leaking to the outside. And it has a Chi off means, the induction heating apparatus the electromagnetic shield ring to place the outer peripheral portion of the low-frequency canceling means.

The induction heating apparatus according to claim 1, wherein the electromagnetic shield ring is configured by forming the lead wire in an annular shape, and the low-frequency canceling means is configured by forming the lead wire in a coil shape.

The induction heating device according to claim 1 or 2, wherein a magnetic body is disposed outside the electromagnetic shield ring.

3. A cable in which two wires are integrated is formed in a coil shape, and one of the two wires is used as a low-frequency magnetic field canceling means, and the other wire is short-circuited at a loop portion and connected in an annular shape to form an electromagnetic shield ring. Or the induction heating apparatus of 3.

The shielded cable signal wire is formed in a coil shape, the shielded cable shaft side wire is used as a low-frequency canceling means, and the shielded wire side wire is short-circuited at the loop portion and connected in an annular shape to form an electromagnetic shield ring. Or the induction heating apparatus of 3.