JP6464051B2 - Induction heating apparatus and induction heating method - Google Patents
Induction heating apparatus and induction heating method Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description
本発明は、金属のワークを誘導加熱する誘導加熱装置、及びその方法に関する。 The present invention relates to an induction heating apparatus and a method for induction heating a metal workpiece.
誘導加熱装置及び誘導加熱方法では、例えば、特許文献１に記載されているように、電源周波数、及び浸透深さ（以下、深度ともいう。）を加熱対象のワークに応じて適切な値とする必要がある。 In the induction heating apparatus and the induction heating method, for example, as described in Patent Document 1, the power supply frequency and the penetration depth (hereinafter, also referred to as depth) are set to appropriate values according to the workpiece to be heated. There is a need.
電源周波数とは、誘導コイルに通電する電流の周波数をいう。深度とは、ワークに誘起される誘導電流（渦電流）の発生位置であってワーク表面からの深さ寸法をいう。つまり、ワークで発生する熱は深度方向で指数関数的に減少するように分布する。このため、深度が不適切であると、ワークを適切に加熱することができない。 The power supply frequency refers to the frequency of the current that flows through the induction coil. The depth is a position where an induced current (eddy current) induced in the work is generated and a depth dimension from the work surface. That is, the heat generated in the work is distributed so as to decrease exponentially in the depth direction. For this reason, if the depth is inappropriate, the workpiece cannot be heated appropriately.
電源周波数及び深度は、ワークの大きさ等に応じた最適値がある。換言すれば、異なる大きさのワークを同一の誘導加熱装置にて誘導加熱することは難しい。このため、ワークの大きさ毎に、当該ワークに適した電源周波数等を実現可能な電源装置を必要とする。 The power supply frequency and depth have optimum values according to the size of the workpiece. In other words, it is difficult to induction-heat workpieces of different sizes with the same induction heating device. For this reason, the power supply device which can implement | achieve the power supply frequency etc. suitable for the said workpiece | work for every size of a workpiece | work is required.
つまり、外形寸法が大きなワークに適した電源周波数等を実現可能な電源装置（以下、第１電源装置という。）、及び外形寸法が小さなワークに適した電源周波数等を実現可能な電源装置（以下、第２電源装置という。）を必要とする。 That is, a power supply device (hereinafter referred to as a first power supply device) capable of realizing a power supply frequency suitable for a workpiece having a large external dimension (hereinafter referred to as a first power supply device), and a power supply device capable of realizing a power supply frequency suitable for a work having a small external dimension (hereinafter referred to as a power supply frequency) The second power supply device).
このため、外形寸法が大きなワークを誘導加熱している場合には第２電源装置が非稼働状態となる。外形寸法が小さなワークを誘導加熱している場合には第１電源装置が非稼働状態となる。したがって、第１電源装置及び第２電源装置の稼働率、つまり、誘導加熱装置の稼働率を上げることが難しい。 For this reason, when the workpiece having a large outer dimension is induction-heated, the second power supply device is in a non-operating state. When the work having a small outer dimension is induction-heated, the first power supply device is not in operation. Therefore, it is difficult to increase the operation rate of the first power supply device and the second power supply device, that is, the operation rate of the induction heating device.
さらに、第１電源装置及び第２電源装置のいずれか一方の電源装置のみでワークを所定温度（例えば、１０００℃）まで加熱する必要があるので、複数の大きな電源装置を必要とする。このため、多額の設備投資を必要とする。 Furthermore, since it is necessary to heat the workpiece to a predetermined temperature (for example, 1000 ° C.) with only one of the first power supply device and the second power supply device, a plurality of large power supply devices are required. For this reason, a large amount of capital investment is required.
本発明は、上記点に鑑み、設備投資額を抑制しつつ、誘導加熱装置全体の稼働率を高めることが可能な誘導加熱装置及び誘導加熱方法を提供する。 In view of the above points, the present invention provides an induction heating apparatus and an induction heating method capable of increasing the operating rate of the entire induction heating apparatus while suppressing the capital investment.
本願では、金属のワークを誘導加熱する誘導加熱装置において、ワーク内に電流を誘起して当該ワークを発熱させる少なくとも１つの誘導コイル（３）と、予め設定された第１周波数の電流を誘導コイル（３）に通電させる第１電源部（５）と、第１周波数より高い第２周波数の電流を誘導コイル（３）に通電させる第２電源部（７）と、ワークを第１周波数にて誘導加熱する場合と当該ワークを第２周波数にて誘導加熱する場合とを切り替える切替装置（９）とを備え、ワークの断面のうち外形寸法が最小となる部位の寸法を外形寸法としたとき、切替装置（９）は、ワークの外形寸法が予め設定された所定寸法未満の場合には、当該ワークを第１周波数にて誘導加熱した後、当該ワークを第２周波数にて誘導加熱し、さらに、ワークの外形寸法が所定寸法以上の場合には、当該ワークを第２周波数にて誘導加熱した後、当該ワークを第１周波数にて誘導加熱する。 In the present application, in an induction heating device for induction heating of a metal workpiece, at least one induction coil (3) for inducing a current in the workpiece to generate heat, and a current having a preset first frequency are introduced into the induction coil. A first power supply section (5) for energizing (3), a second power supply section (7) for energizing the induction coil (3) with a current having a second frequency higher than the first frequency, and the work at the first frequency. A switching device (9) that switches between induction heating and induction heating of the workpiece at the second frequency, and when the dimension of the portion of the cross section of the workpiece that has the smallest outer dimension is taken as the outer dimension, The switching device (9), when the external dimension of the work is less than a predetermined dimension set in advance, after induction heating the work at the first frequency, induction heating the work at the second frequency, Outside the work If the size is greater than the predetermined size, after induction heat the workpiece at a second frequency, to inductively heat the workpiece at a first frequency.
これにより、本願発明では、設備投資額を抑制しつつ、誘導加熱装置全体の稼働率を高めることが可能となる。すなわち、通電時の周波数が高くなるほど、深度が小さくなる傾向がある。したがって、周波数が高くなると、誘導電流はワークの表層部で発生し、ワークの中心部で発生し難くなる。 Thereby, in this invention, it becomes possible to raise the operation rate of the whole induction heating apparatus, suppressing the capital investment amount. That is, the depth tends to decrease as the frequency during energization increases. Therefore, when the frequency is increased, the induced current is generated in the surface layer portion of the workpiece and is hardly generated in the center portion of the workpiece.
このため、薄板材のように外形寸法が小さいワークでは、理論上の深度がワークの外形寸法を越えてしまう場合がある。この場合には、当該ワークを効率よく加熱することが困難である。厚板材のように外形寸法が大きいワークでは、理論上の深度がワークの断面中心から大きくずれてしまう場合がある。この場合には、当該ワーク全体を均一に加熱することが難しい。 For this reason, in a work having a small outer dimension such as a thin plate material, the theoretical depth may exceed the outer dimension of the work. In this case, it is difficult to efficiently heat the workpiece. In a workpiece having a large outer dimension such as a thick plate material, the theoretical depth may deviate greatly from the cross-sectional center of the workpiece. In this case, it is difficult to uniformly heat the entire workpiece.
また、周波数が同一であっても、ワークの温度が異なると、深度が異なる。特に、金属においては、周波数が同一であっても、ワークの温度が特定温度を越えると、当該特定温度未満のときに比べて深度が著しく大きくなる。 Moreover, even if the frequency is the same, the depth is different if the temperature of the workpiece is different. In particular, in the case of a metal, even if the frequency is the same, when the temperature of the workpiece exceeds a specific temperature, the depth becomes significantly larger than when the temperature is lower than the specific temperature.
つまり、ワーク温度が特定温度未満のときには、周波数が相違しても深度が大きく変化しないのに対して、ワーク温度が特定温度以上のときには、周波数の変化に応じて深度が大きく変化する。 That is, when the workpiece temperature is lower than the specific temperature, the depth does not change greatly even if the frequency is different, whereas when the workpiece temperature is equal to or higher than the specific temperature, the depth changes greatly according to the change in frequency.
そこで、本願発明では、ワークの外形寸法が所定寸法未満の場合には、当該ワークを第１周波数にて誘導加熱した後、当該ワークを第２周波数にて誘導加熱することにより、理論上の深度がワークの外形寸法を越えてしまうことを抑制して当該ワークを効率よく加熱可能とする。 Therefore, in the present invention, when the outer dimension of the workpiece is less than the predetermined dimension, the theoretical depth is obtained by induction heating the workpiece at the first frequency and then induction heating the workpiece at the second frequency. Is prevented from exceeding the outer dimension of the workpiece, and the workpiece can be efficiently heated.
ワークの外形寸法が所定寸法以上の場合には、当該ワークを第２周波数にて誘導加熱した後、当該ワークを第１周波数にて誘導加熱することにより、理論上の深度がワークの断面中心から大きくずれてしまうことを抑制して当該ワーク全体を均一に加熱可能とする。 When the outer dimension of the workpiece is equal to or larger than the predetermined dimension, the theoretical depth is determined from the center of the cross section of the workpiece by induction heating the workpiece at the second frequency and then induction heating the workpiece at the first frequency. It is possible to uniformly heat the entire workpiece while suppressing a large shift.
そして、本願発明では、第１電源部（５）及び第２電源部（７）を利用してワークを加熱する。このため、１つの電源部にてワークを加熱する場合に比べて、各電源部（５、７）の能力を小さくすることが可能となるとともに、誘導加熱装置全体（特に、第１電源部（５）及び第２電源部（７））の稼働率を高めることができ得る。 And in this invention, a workpiece | work is heated using a 1st power supply part (5) and a 2nd power supply part (7). For this reason, it is possible to reduce the capacity of each power supply unit (5, 7) as compared with the case where the work is heated by one power supply unit, and the entire induction heating device (particularly, the first power supply unit ( 5) and the operating rate of the second power supply unit (7) can be increased.
以上により、本願発明では、設備投資額を抑制しつつ、誘導加熱装置全体の稼働率を高めることが可能となる。
なお、特定温度は、ワークの物性値等によって決まる値である。したがって、ワークの磁気変態点を基準に予め設定された温度を変更温度としたとき、ワークの温度を検出する温度検出器（１１Ａ、１１Ｂ）を備え、切替装置（９）は、温度検出器（１１Ａ、１１Ｂ）により検出された温度が変更温度に到達したときに、誘導加熱に用いる周波数を変更する構成とすることが望ましい。
As described above, in the present invention, it is possible to increase the operating rate of the entire induction heating apparatus while suppressing the capital investment.
The specific temperature is a value determined by the physical property value of the workpiece. Accordingly, the temperature detector (11A, 11B) that detects the temperature of the workpiece when the temperature preset in relation to the magnetic transformation point of the workpiece is used as the change temperature, the switching device (9) includes the temperature detector ( It is desirable that the frequency used for induction heating is changed when the temperature detected by 11A and 11B) reaches the changed temperature.
因みに、上記各手段等の括弧内の符号は、後述する実施形態に記載の具体的構成等との対応関係を示す一例であり、本発明は上記各手段等の括弧内の符号に示された具体的構成等に限定されるものではない。 Incidentally, the reference numerals in parentheses for each of the above means are examples showing the correspondence with the specific configurations described in the embodiments described later, and the present invention is indicated by the reference numerals in the parentheses of each of the above means, etc. It is not limited to a specific configuration or the like.
以下に説明する「発明の実施形態」は実施形態の一例を示すものである。つまり、特許請求の範囲に記載された発明特定事項等は、下記の実施形態に示された具体的構成や構造等に限定されるものではない。 The “embodiment of the invention” described below shows an example of the embodiment. In other words, the invention specific items described in the claims are not limited to the specific configurations and structures shown in the following embodiments.
本実施形態は、金属製の板バネ（以下、ワークＷという。）を誘導加熱する誘導加熱装置に本発明を適用したものである。各図に付された方向を示す矢印等は、各図相互の関係を理解し易くするために記載したものである。本発明は、各図に付された方向に限定されるものではない。 In the present embodiment, the present invention is applied to an induction heating apparatus for induction heating a metal leaf spring (hereinafter referred to as a workpiece W). The arrows and the like indicating the directions given to the drawings are described for easy understanding of the relationship between the drawings. The present invention is not limited to the directions given in the drawings.
少なくとも符号を付して説明した部材又は部位は、「複数」や「２つ以上」等の断りをした場合を除き、少なくとも１つ設けられている。以下、本発明の実施形態を図面と共に説明する。 At least one member or part described with at least a reference numeral is provided, except where “plurality”, “two or more”, and the like are omitted. Hereinafter, embodiments of the present invention will be described with reference to the drawings.
（第１実施形態）
１．誘導加熱装置の概要
図１は、本実施形態に係る誘導加熱方法を用いた誘導加熱装置１の模式図である。誘導加熱装置１は、誘導コイル３、第１電源部５、第２電源部７及び切替装置９等を少なくとも備える。
(First embodiment)
1. Outline of Induction Heating Device FIG. 1 is a schematic diagram of an induction heating device 1 using an induction heating method according to the present embodiment. The induction heating device 1 includes at least an induction coil 3, a first power supply unit 5, a second power supply unit 7, a switching device 9, and the like.
誘導コイル３はワークＷ内に電流を誘起して当該ワークＷを発熱させる。本実施形態に係る誘導コイル３は、第１誘導コイル３Ａ及び第２誘導コイル３Ｂを有して構成されている。以下、なお、第１誘導コイル３Ａ及び第２誘導コイル３Ｂを総称する場合には、誘導コイル３と記す。 The induction coil 3 induces a current in the workpiece W to cause the workpiece W to generate heat. The induction coil 3 according to the present embodiment includes a first induction coil 3A and a second induction coil 3B. Hereinafter, the first induction coil 3A and the second induction coil 3B are collectively referred to as the induction coil 3.
第１誘導コイル３Ａは第１電源部５より通電される。第２誘導コイル３Ｂは第２電源部７により通電される。本実施形態に係る誘導コイル３は、楕円を描くように螺旋状に巻かれている。 The first induction coil 3 </ b> A is energized from the first power supply unit 5. The second induction coil 3 </ b> B is energized by the second power supply unit 7. The induction coil 3 according to the present embodiment is spirally wound so as to draw an ellipse.
すなわち、本実施形態に係るワークＷは、その長手方向と直交する断面（以下、ワーク断面という。）の形状が長方形状の帯板である。そして、誘導コイル３は、その長径方向がワーク断面の長手方向と平行となるような楕円形状である。以下、ワーク断面のうち外形寸法が最小となる部位の寸法（本実施形態では、ワークＷの厚み寸法）を外形寸法という。 That is, the workpiece W according to the present embodiment is a strip having a rectangular cross section (hereinafter referred to as a workpiece cross section) orthogonal to the longitudinal direction. The induction coil 3 has an elliptical shape whose major axis direction is parallel to the longitudinal direction of the workpiece cross section. Hereinafter, the dimension of the part having the smallest outer dimension (in this embodiment, the thickness dimension of the work W) in the workpiece cross section is referred to as the outer dimension.
第１電源部５は、予め設定された第１周波数の電流を第１誘導コイル３Ａに通電させる。第２電源部７は、予め設定された第２周波数の電流を第２誘導コイル３Ｂに通電させる。第２周波数は第１周波数より高い周波数である。 The first power supply unit 5 energizes the first induction coil 3 </ b> A with a current having a preset first frequency. The second power supply unit 7 energizes the second induction coil 3B with a current having a preset second frequency. The second frequency is higher than the first frequency.
第１周波数及び第２周波数の具体的な周波数は、ワークＷの材質、形状、外形寸法及び加熱温度等によって適宜選定される。以下、第１周波数を「中周波」ともいう。第２周波数を「高周波」ともいう。誘導コイル３に通電する電流の周波数を加熱周波数ともいう。 Specific frequencies of the first frequency and the second frequency are appropriately selected according to the material, shape, outer dimensions, heating temperature, and the like of the workpiece W. Hereinafter, the first frequency is also referred to as “medium frequency”. The second frequency is also referred to as “high frequency”. The frequency of the current that flows through the induction coil 3 is also referred to as a heating frequency.
切替装置９は、ワークＷを中周波にて誘導加熱する場合と当該ワークＷを高周波にて誘導加熱する場合とを切り替える。本実施形態に係る切替装置９では、ワークＷを第１誘導コイル３Ａ内に挿入する場合と当該ワークＷを第２誘導コイル３Ｂ内に挿入する場合とを切り替えることにより加熱周波数を切り替えている。 The switching device 9 switches between a case where the work W is induction-heated at a medium frequency and a case where the work W is induction-heated at a high frequency. In the switching device 9 according to the present embodiment, the heating frequency is switched by switching between the case where the workpiece W is inserted into the first induction coil 3A and the case where the workpiece W is inserted into the second induction coil 3B.
具体的には、本実施形態に係る切替装置９は、ワークＷを搬送する搬送機９Ａ、及びワークＷを搬送機９Ａと誘導コイル３との間で移送させるワーク投入用ロボットアーム（図示せず。）等を有して構成される。 Specifically, the switching device 9 according to the present embodiment includes a transporter 9A that transports the workpiece W, and a workpiece loading robot arm (not shown) that transports the workpiece W between the transporter 9A and the induction coil 3. Etc.).
第１電源部５、第２電源部７並びに切替装置９（搬送機９Ａ及びワーク投入用ロボットアーム）等の作動は、制御装置（図示せず。）により制御される。制御装置は、ＣＰＵ、ＲＯＭ及びＲＡＭ等を有するコンピュータにて構成されている。 The operations of the first power supply unit 5, the second power supply unit 7, the switching device 9 (the transfer machine 9A and the workpiece loading robot arm), and the like are controlled by a control device (not shown). The control device is configured by a computer having a CPU, a ROM, a RAM, and the like.
２．ワークの誘導加熱方法
制御装置は、ワークＷを加熱する際の加熱周波数を、以下のように切替制御する。
すなわち、切替装置９（制御装置）は、ワークＷの外形寸法が予め設定された所定寸法未満の場合には、当該ワークＷを中周波にて誘導加熱した後、当該ワークＷを高周波にて誘導加熱する（図１参照）。
2. Induction Heating Method for Workpiece The control device switches and controls the heating frequency when heating the workpiece W as follows.
That is, the switching device 9 (control device), when the outer dimension of the workpiece W is less than a predetermined dimension set in advance, induction-heats the workpiece W at medium frequency and then induces the workpiece W at high frequency. Heat (see FIG. 1).
さらに、切替装置９（制御装置）は、ワークＷの外形寸法が前記所定寸法以上の場合には、当該ワークＷを高周波にて誘導加熱した後、当該ワークＷを中周波にて誘導加熱する（図２参照）。 Further, when the outer dimension of the workpiece W is equal to or larger than the predetermined dimension, the switching device 9 (control device) performs induction heating of the workpiece W at a high frequency and then induction heating of the workpiece W at a medium frequency ( (See FIG. 2).
加熱周波数は、ワークＷの温度が変更温度に到達したときに切り替えられる。変更温度とは、ワークＷの磁気変態点を基準に予め設定された温度をいう。このため、制御装置には、赤外線温度センサ等の非接触でワークＷの表面温度を検出する温度検出器１１Ａ、１１Ｂの出力信号が入力されている。 The heating frequency is switched when the temperature of the workpiece W reaches the change temperature. The change temperature refers to a temperature set in advance based on the magnetic transformation point of the workpiece W. For this reason, the output signals of the temperature detectors 11A and 11B that detect the surface temperature of the workpiece W in a non-contact manner such as an infrared temperature sensor are input to the control device.
制御装置は、温度検出器１１Ａ、１１Ｂの出力信号を利用してワークＷの温度が変更温度に到達したか否かを判定して、加熱周波数を切り替える。なお、ワークＷの外形寸法及び変更温度は、誘導加熱装置１にワークＷが搬送されてきたときに、自動的又は作業者による手動操作により制御装置に入力される。 The control device determines whether or not the temperature of the workpiece W has reached the changed temperature using the output signals of the temperature detectors 11A and 11B, and switches the heating frequency. Note that the outer dimensions and the change temperature of the workpiece W are input to the control device automatically or manually by an operator when the workpiece W is conveyed to the induction heating device 1.
３．本実施形態に係る誘導加熱装置（誘導加熱方法）の特徴
通電時の周波数（加熱周波数）が高くなるほど、深度が小さくなる傾向がある。したがって、加熱周波数が高くなると、誘導電流はワークＷの表層部で発生し、ワークＷの中心部で発生し難くなる。
3. Characteristics of Induction Heating Device (Induction Heating Method) According to the Present Embodiment As the frequency (heating frequency) at the time of energization increases, the depth tends to decrease. Therefore, when the heating frequency is increased, the induced current is generated at the surface layer portion of the workpiece W and is hardly generated at the center portion of the workpiece W.
このため、厚板材のように外形寸法が大きいワークＷでは、理論上の深度がワークＷの断面中心から大きくずれてしまう場合がある。この場合には、当該ワークＷ全体を均一に加熱することが難しい。 For this reason, in a workpiece W having a large outer dimension such as a thick plate material, the theoretical depth may deviate greatly from the cross-sectional center of the workpiece W. In this case, it is difficult to uniformly heat the entire workpiece W.
薄板材のように外形寸法が小さいワークＷでは、理論上の深度がワークＷの外形寸法を越えてしまう場合がある。この場合には、当該ワークＷを効率よく加熱することが困難である。 In a workpiece W having a small outer dimension such as a thin plate material, the theoretical depth may exceed the outer dimension of the workpiece W. In this case, it is difficult to efficiently heat the workpiece W.
また、加熱周波数が同一であっても、ワークＷの温度が異なると、深度が異なる。特に、金属においては、加熱周波数が同一であっても、ワークＷの温度が特定温度を越えると、当該特定温度未満のときに比べて深度が著しく大きくなる。 Further, even if the heating frequency is the same, the depth is different if the temperature of the workpiece W is different. In particular, in the case of metal, even if the heating frequency is the same, when the temperature of the workpiece W exceeds a specific temperature, the depth becomes significantly larger than when the temperature is lower than the specific temperature.
つまり、ワーク温度が特定温度未満のときには、加熱周波数が相違しても深度が大きく変化しないのに対して、ワーク温度が特定温度以上のときには、周波数の変化に応じて深度が大きく変化する。 That is, when the work temperature is lower than the specific temperature, the depth does not change greatly even if the heating frequency is different, whereas when the work temperature is equal to or higher than the specific temperature, the depth changes greatly according to the change in frequency.
そこで、本実施形態では、ワークＷの外形寸法が所定寸法未満の場合には、当該ワークＷを中周波にて誘導加熱した後、当該ワークＷを高周波にて誘導加熱することより、理論上の深度がワークの外形寸法を越えてしまうことを抑制して当該ワークＷを効率よく加熱可能とする。 Therefore, in the present embodiment, when the outer dimension of the work W is less than a predetermined dimension, the work W is induction-heated at a medium frequency, and then the work W is induction-heated at a high frequency. It is possible to efficiently heat the workpiece W while suppressing the depth from exceeding the outer dimension of the workpiece.
ワークの外形寸法が所定寸法以上の場合には、当該ワークＷを高周波にて誘導加熱した後、当該ワークＷを中周波にて誘導加熱することにより、理論上の深度がワークの断面中心から大きくずれてしまうことを抑制して当該ワークＷ全体を均一に加熱可能とする。 When the outer dimension of the workpiece is greater than or equal to a predetermined dimension, the theoretical depth is increased from the cross-sectional center of the workpiece by induction heating the workpiece W at a high frequency and then induction heating the workpiece W at a medium frequency. It is possible to uniformly heat the entire workpiece W while suppressing the displacement.
そして、本実施形態では、第１電源部５及び第２電源部７を利用してワークを加熱する。このため、１つの電源部にてワークを加熱する場合に比べて、各電源部５、７の能力を小さくすることが可能となるとともに、誘導加熱装置全体（特に、第１電源部５及び第２電源部７）の稼働率を高めることができ得る。 In this embodiment, the workpiece is heated using the first power supply unit 5 and the second power supply unit 7. For this reason, compared with the case where a workpiece | work is heated by one power supply part, while it becomes possible to reduce the capability of each power supply part 5 and 7, the whole induction heating apparatus (especially the 1st power supply part 5 and the 1st) It is possible to increase the operating rate of the two power supply units 7).
例えば、１つの電源にてワークＷを１０００℃昇温可能とするには、大きな容量の電源を必要とする。これに対して、本実施形態では、例えば、第１電源部５にて５００℃昇温可能とし、第２電源部７にて５００℃昇温可能とすれば、各電源５、７の容量を小さくすることができる。 For example, in order to increase the temperature of the workpiece W by 1000 ° C. with a single power source, a large capacity power source is required. On the other hand, in the present embodiment, for example, if the first power supply unit 5 can increase the temperature by 500 ° C. and the second power supply unit 7 can increase the temperature by 500 ° C., the capacity of each of the power supplies 5 and 7 can be increased. Can be small.
以上により、本実施形態では、設備投資額を抑制しつつ、誘導加熱装置全体の稼働率を高めることが可能となる。
（その他の実施形態）
上述の実施形態では、第１誘導コイル３Ａ及び第２誘導コイル３Ｂを用いてワークＷへの加熱周波数を切り替えたが、本発明はこれに限定されるものではない。
As described above, in this embodiment, it is possible to increase the operating rate of the entire induction heating apparatus while suppressing the capital investment.
(Other embodiments)
In the above-described embodiment, the heating frequency to the workpiece W is switched using the first induction coil 3A and the second induction coil 3B, but the present invention is not limited to this.
すなわち、例えば、誘導コイル３を１つとし、その誘導コイル３に第１電源部５から通電する場合と第２電源部７から通電する場合とを切り替えることにより、ワークＷへの加熱周波数を切り替えてもよい。なお、この場合、通電切替タイミングを制御する制御装置が切替装置９に相当する。 That is, for example, the number of induction coils 3 is one, and the heating frequency to the workpiece W is switched by switching between the case where the induction coil 3 is energized from the first power supply unit 5 and the case where the induction coil 3 is energized from the second power supply unit 7. May be. In this case, the control device that controls the energization switching timing corresponds to the switching device 9.
上述の実施形態では、ワークＷの温度が変更温度に到達したときにワークＷへの加熱周波数を切り替えたが、本発明はこれに限定されるものではなく、例えば、第１周波数で加熱する時間、及び第２周波数で加熱する時間をワークＷの材質及び外形寸法毎に予め設定しておき、その加熱時間に従ってワークＷへの加熱周波数を切り替えてもよい。 In the above-described embodiment, the heating frequency for the workpiece W is switched when the temperature of the workpiece W reaches the change temperature. However, the present invention is not limited to this, for example, the time for heating at the first frequency. The time for heating at the second frequency may be preset for each material and outer dimension of the workpiece W, and the heating frequency for the workpiece W may be switched according to the heating time.
上述の実施形態では、２段階に分けてワークＷを誘導加熱したが、本発明はこれに限定されるものではなく、例えば、３段階（低周波、中周波、高周波）に分けてワークＷを誘導加熱してもよい。 In the above-described embodiment, the work W is induction-heated in two stages, but the present invention is not limited to this. For example, the work W is divided into three stages (low frequency, medium frequency, and high frequency). Induction heating may be used.
上述の実施形態では、帯板状のワークＷを加熱対象とした例であったが、本発明はこれに限定されるものではなく、その他形状のワークＷであってもよい。なお、ワーク断面が円形の場合には、外形寸法は直径寸法となる。ワーク断面が正方形の場合には、外形寸法は対角線寸法となる。 In the above-described embodiment, the belt-shaped workpiece W is an example to be heated. However, the present invention is not limited to this, and the workpiece W may have other shapes. When the workpiece cross section is circular, the outer dimension is a diameter dimension. When the workpiece cross section is square, the outer dimension is a diagonal dimension.
上述の実施形態に係る温度検出器１１Ａ、１１Ｂは、赤外線温度センサ等の非接触でワークＷの表面温度を検出するものであったが、本発明はこれに限定されるものではなく、例えば、電気抵抗値の変化を検出する等の接触してワークＷの温度を検出する温度検出器であってもよい。 Although the temperature detectors 11A and 11B according to the above-described embodiment detect the surface temperature of the workpiece W in a non-contact manner such as an infrared temperature sensor, the present invention is not limited to this. For example, A temperature detector that detects the temperature of the workpiece W by contact such as detecting a change in the electrical resistance value may be used.
上述の実施形態に係る誘導コイル３は、楕円状に巻かれたものであったが、本発明はこれに限定されるものではなく、例えば、円形又は矩形状等に巻かれたものであってもよい。 Although the induction coil 3 according to the above-described embodiment has been wound in an elliptical shape, the present invention is not limited to this, and is, for example, wound in a circular or rectangular shape. Also good.
また、本発明は、特許請求の範囲に記載された発明の趣旨に合致するものであればよく、上述の実施形態に限定されるものではない。 Further, the present invention is not limited to the above-described embodiment as long as it matches the gist of the invention described in the claims.
１… 誘導加熱装置
３… 誘導コイル
３Ａ… 第１誘導コイル
３Ｂ… 第２誘導コイル
５… 第１電源部
５… 各電源部
７… 第２電源部
９… 切替装置
９Ａ… 搬送機
DESCRIPTION OF SYMBOLS 1 ... Induction heating apparatus 3 ... Induction coil 3A ... 1st induction coil 3B ... 2nd induction coil 5 ... 1st power supply part 5 ... Each power supply part 7 ... 2nd power supply part 9 ... Switching apparatus 9A ... Conveyor
Claims (5)
ワーク内に電流を誘起して当該ワークを発熱させる少なくとも１つの誘導コイルと、
予め設定された第１周波数の電流を前記誘導コイルに通電させる第１電源部と、
前記第１周波数より高い第２周波数の電流を前記誘導コイルに通電させる第２電源部と、
ワークを前記第１周波数にて誘導加熱する場合と当該ワークを前記第２周波数にて誘導加熱する場合とを切り替える切替装置とを備え、
ワークの断面のうち外形寸法が最小となる部位の寸法を外形寸法としたとき、
前記切替装置は、ワークの外形寸法が予め設定された所定寸法未満の場合には、当該ワークを前記第１周波数にて誘導加熱した後、当該ワークを前記第２周波数にて誘導加熱し、
さらに、ワークの外形寸法が前記所定寸法以上の場合には、当該ワークを前記第２周波数にて誘導加熱した後、当該ワークを前記第１周波数にて誘導加熱する
ことを特徴とする誘導加熱装置。 In an induction heating device for induction heating of a metal workpiece,
At least one induction coil that induces an electric current in the workpiece to heat the workpiece;
A first power supply unit for energizing the induction coil with a current having a first frequency set in advance;
A second power supply unit for energizing the induction coil with a current having a second frequency higher than the first frequency;
A switching device that switches between induction heating of the work at the first frequency and induction heating of the work at the second frequency;
When the dimension of the part where the outer dimension is the smallest in the cross section of the workpiece is the outer dimension,
If the external dimension of the workpiece is less than a predetermined dimension set in advance, the switching device induction-heats the workpiece at the first frequency, and then induction-heats the workpiece at the second frequency.
Furthermore, when the external dimension of the workpiece is equal to or greater than the predetermined dimension, the workpiece is induction-heated at the first frequency after the workpiece is induction-heated at the second frequency. .
ワークの温度を検出する温度検出器を備え、
前記切替装置は、前記温度検出器により検出された温度が前記変更温度に到達したときに、誘導加熱に用いる周波数を変更する
ことを特徴とする請求項１に記載の誘導加熱装置。 When the temperature set in advance based on the magnetic transformation point of the workpiece is used as the change temperature,
It has a temperature detector that detects the temperature of the workpiece,
The induction heating device according to claim 1, wherein the switching device changes a frequency used for induction heating when the temperature detected by the temperature detector reaches the change temperature.
ワークの断面のうち外形寸法が最小となる部位の寸法を外形寸法とし、予め設定された第１周波数より高い周波数を第２周波数としたとき、
ワークの外形寸法が予め設定された所定寸法未満の場合には、当該ワークを前記第１周波数にて誘導加熱した後、当該ワークを前記第２周波数にて誘導加熱し、
さらに、ワークの外形寸法が前記所定寸法以上の場合には、当該ワークを前記第２周波数にて誘導加熱した後、当該ワークを前記第１周波数にて誘導加熱する
ことを特徴とする誘導加熱方法。 In an induction heating method for induction heating a metal workpiece,
When the dimension of the part where the outer dimension is the smallest in the cross section of the workpiece is the outer dimension, and the frequency higher than the preset first frequency is the second frequency,
If the outer dimension of the workpiece is less than a predetermined dimension set in advance, after the workpiece is induction heated at the first frequency, the workpiece is induction heated at the second frequency,
Furthermore, when the outer dimension of the workpiece is equal to or larger than the predetermined dimension, the workpiece is induction-heated at the first frequency after the workpiece is induction-heated at the second frequency. .
ワークの温度が前記変更温度に到達したときに、誘導加熱に用いる周波数を変更する
ことを特徴とする請求項４に記載の誘導加熱方法。 When the temperature set in advance based on the magnetic transformation point of the workpiece is used as the change temperature,
The induction heating method according to claim 4, wherein the frequency used for induction heating is changed when the temperature of the workpiece reaches the change temperature.
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