JP3834975B2

JP3834975B2 - Induction heating device

Info

Publication number: JP3834975B2
Application number: JP33396597A
Authority: JP
Inventors: 聡山田; 裕関野
Original assignee: Meidensha Corp
Current assignee: Meidensha Corp
Priority date: 1997-12-04
Filing date: 1997-12-04
Publication date: 2006-10-18
Anticipated expiration: 2017-12-04
Also published as: JPH11167983A

Description

【０００１】
【発明の属する技術分野】
本発明は誘導加熱装置に関し、ワークの昇温後の保温が適正になされるようにしたものである。
【０００２】
【従来の技術】
ワークを熱処理するには、誘導加熱装置が用いられる。熱処理の手順としては、図４に示すように一定の時間ｔ₁内にワークの温度をＴまで昇温させたのちに、温度Ｔで時間ｔ₂だけワークを保温し、最後に時間ｔ₃内にワークの温度を常温まで急冷する。
【０００３】
図４のパターンでワークを熱処理する場合、従来例１，２の２つの方式が用いられている。
【０００４】
まず、従来例１について説明する。図５に示すように昇温コイル１，保温筒２ａと水冷等による冷却器３とがラインに沿って架台１３上に配置され、ワーク４が矢印の方向へ移送される。そして、図６に示すように電源５からインバータ６，マッチング回路６を介して昇温コイル１のみに電力が供給される。ここで、保温筒２ａの長さＬは最高ライン速度Ｖｍａｘ及び最低必要保温時間ｔ₂ｍｉｎによって決定される。
【０００５】
次に、従来例２について説明する。図７に示すように昇温コイル１等が配置されている。従来例２は従来例１と異なり、保温筒２ａに代えて強制加熱用の保温コイル２ｂが用いられ、そのために図８に示すように保温コイル２ｂにも電力が供給される。保温コイル２ｂの長さＬも前記の保温筒２ａの長さと同様にして決定される。
【０００６】
【発明が解決しようとする課題】
ところが、従来例１では昇温コイルのみによる加熱であるため、保温筒を通過中に熱の輻射，熱伝導等によってワークの温度が図９のように低下する。また、保温筒の長さＬは前記のようにして決定されるため、保温温度の許容範囲が狭く、ライン速度が小さい場合は保温温度の下限を下回ってしまう。
【０００７】
従来例２では保温コイルの長さＬは前記のようにして決定されるが、ライン速度が小さいときでも必要以上に長いコイルで加熱することになり、コスト高になる。また、ワークは誘導加熱装置の前後のみに設けられた上下一対の搬送用ロール（図示せず）で拘束されているため、長いコイルで長時間ワークを加熱すると自重変形等によりワークの形状に悪影響を及ぼす恐れがある。
【０００８】
そこで本発明は、斯る課題を解決した誘導加熱装置を提供することを目的とする。
【０００９】
【課題を解決するための手段】
斯る目的を達成するための請求項１に係る誘導加熱装置の構成は、ワークを移送するラインに沿って、ワークの温度を所定温度まで昇温させる昇温コイルと、ワークを所定温度に保持する保温手段と、ワークを所定温度から常温まで冷却する冷却器とを順に配置し、前記保温手段は、発熱を伴うことなくワークを保温する保温筒と発熱を伴う保温コイルとをラインの流れる方向に沿って順に配置した組み合わせを少なくとも１対設けて構成し、前記保温筒はライン上に着脱自在に設ける一方、前記保温コイルはラインに沿って移動可能に設け、前記冷却器はラインに沿って移動可能に設けたことを特徴とする。
【００１０】
【発明の実施の形態】
以下、本発明による誘導加熱装置の実施の形態を説明する。
【００１１】
（ａ）実施の形態１
まず、ライン速度が大きいために一定時間だけ保温するには長い保温スペースが必要な場合の誘導加熱装置の構成を図１に示す。この場合は、図のように、ワーク４の移送されるラインに沿って、昇温コイル１，保温手段９，冷却器１２が配置され、保温手段９は単一の保温筒１０と単一の保温コイル１１とで構成されている。
【００１２】
昇温コイル1は従来と同じであって発熱を伴うものである。保温筒１０は発熱を伴うことはなくワークの熱が逃げるのを防止するためにワークの周囲を覆う筒形状にしたものであり、架台１３に対して着脱自在に設けられている。発熱を伴う保温コイル１１と冷却器１２は、車輪１４を設けることでラインに沿って移動自在に構成されている。
【００１３】
斯る誘導加熱装置では、保温コイル１１と冷却器１２とをラインに沿って動かすことにより、保温手段９の占める保温スペースＳの長さを自由に設定することができる。このため、ライン速度が大きくて長い保温スペースが必要な場合のワークの誘導加熱を適正に行うことができる。
【００１４】
（ｂ）実施の形態２
次に、ライン速度が小さいために一定時間だけ保温するには短い保温スペースで足りる場合の誘導加熱装置の構成を図２に示す。この場合は、図のように保温手段９として発熱を伴う保温コイル１１のみを設けたものである。
【００１５】
斯る誘導加熱装置は、図１における実施の形態１のライン上から保温筒１０を取り除き、保温コイル１１及び冷却器１２を図中の左方へ移動させることによって構成することができる。保温手段９が、保温コイル１１のみによって構成されるために保温スペースＳの長さが短く、ライン速度が小さくて短い保温スペースが必要な場合のワークの誘導加熱を適正に行うことができる。
【００１６】
（ｃ）実施の形態３
最後に、ライン速度が実施の形態１の場合よりも大きい場合の誘導加熱装置を図３に示す。この場合は、図１が保温手段９として保温筒１０，保温コイル１１の組み合わせたものを一対設けたのに対して２対設けて、ワークの搬送速度が大きくなった分だけ保温スペースＳを長くして保温時間を一定にしたものである。なお、保温筒１０，保温コイル１１を３対以上設けてもよい。
【００１７】
その他の構成，作用は実施の形態１と同じなので、説明を省略する。
【００１８】
なお、実施の形態１では保温手段として保温筒と保温コイルとからなる組み合わせを１対設け、実施の形態３では２対設けたが、３対以上設けてもよい。
【００１９】
【発明の効果】
以上の説明からわかるように、請求項１に係る誘導加熱装置によれば保温手段を発熱を伴うことなくワークを保温する保温筒と発熱を伴う保温コイルとをラインの流れる方向に沿って順に配置した組み合わせを少なくとも１対設けて構成したので、ライン速度が大きくて長い保温スペースが必要な場合のワークの誘導加熱を適正に行うことができ、保温スペースの全体に保温コイルを配置する場合に比べて製造コストを下げることができる。
【００２０】
また、保温スペースの長さを変更できるため、ライン速度が小さい場合から大きい場合までの全ての範囲にわたって保温時間を同等にすることができる。そして、長い保温スペースを設けることによりワークを支持する搬送用ロール間の長さが必要以上に大きくなりワークが自重によって変形する等の悪影響がなくなる。
【図面の簡単な説明】
【図１】本発明による誘導加熱装置の実施の形態１を示す構成図。
【図２】本発明による誘導加熱装置の実施の形態２を示す構成図。
【図３】本発明による誘導加熱装置の実施の形態３を示す構成図。
【図４】ワークを熱処理する際の時間と温度との関係を示すグラフ。
【図５】誘導加熱装置の従来例１を示す構成図。
【図６】誘導加熱装置の従来例１における電気系統を示す構成図。
【図７】誘導加熱装置の従来例２を示す構成図。
【図８】誘導加熱装置の従来例２における電気系統を示す構成図。
【図９】従来例１の欠点を示すためのグラフ。
【符号の説明】
１…昇温コイル
４…ワーク
９…保温手段
１０…保温筒
１１…保温コイル
１２…冷却器
１４…車輪[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating apparatus, and is intended to appropriately keep the temperature of a workpiece after the temperature is raised.
[0002]
[Prior art]
An induction heating device is used to heat treat the workpiece. As shown in FIG. 4, after the temperature of the workpiece is raised to T within a certain time t ₁ as shown in FIG. 4, the temperature of the workpiece is kept at temperature T for time t ₂ , and finally within time t ₃ . Quickly cool the workpiece to room temperature.
[0003]
When the workpiece is heat-treated with the pattern of FIG. 4, the two methods of Conventional Examples 1 and 2 are used.
[0004]
First, Conventional Example 1 will be described. As shown in FIG. 5, the temperature raising coil 1, the heat retaining cylinder 2a, and the cooler 3 by water cooling or the like are arranged on the mount 13 along the line, and the work 4 is transferred in the direction of the arrow. Then, as shown in FIG. 6, power is supplied only from the power source 5 to the temperature raising coil 1 through the inverter 6 and the matching circuit 6. Here, the length L of the heat insulating cylinder 2a is determined by the maximum line speed Vmax and the minimum required heat insulating time t ₂ min.
[0005]
Next, Conventional Example 2 will be described. As shown in FIG. 7, a heating coil 1 and the like are arranged. Unlike the conventional example 1, the conventional example 2 uses a heat-insulating coil 2b for forced heating instead of the heat-insulating cylinder 2a. For this purpose, power is also supplied to the heat-insulating coil 2b as shown in FIG. The length L of the heat insulation coil 2b is also determined in the same manner as the length of the heat insulation cylinder 2a.
[0006]
[Problems to be solved by the invention]
However, in the conventional example 1, since the heating is performed only by the temperature raising coil, the temperature of the work is lowered as shown in FIG. 9 due to heat radiation, heat conduction or the like while passing through the heat insulating cylinder. In addition, since the length L of the heat insulation cylinder is determined as described above, if the allowable range of the heat insulation temperature is narrow and the line speed is low, the temperature is below the lower limit of the heat insulation temperature.
[0007]
In Conventional Example 2, the length L of the heat retaining coil is determined as described above. However, even when the line speed is low, heating is performed with a coil longer than necessary, resulting in an increase in cost. In addition, since the work is restrained by a pair of upper and lower conveying rolls (not shown) provided only before and after the induction heating device, if the work is heated for a long time with a long coil, the work shape is adversely affected by its own weight deformation or the like. There is a risk of affecting.
[0008]
Then, an object of this invention is to provide the induction heating apparatus which solved such a subject.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, the structure of the induction heating apparatus according to claim 1 includes a heating coil for raising the temperature of the workpiece to a predetermined temperature along the line for transferring the workpiece, and holding the workpiece at the predetermined temperature. And a cooler that cools the workpiece from a predetermined temperature to room temperature, and the heat retaining unit is configured to flow in a line between a heat retaining cylinder that retains the workpiece without heat generation and a heat retaining coil that generates heat. at least one pair provided to constitute the combination are arranged in this order along the while heat insulating tube is provided removably on the line, the heat insulating coil movably provided along the lines, the cooler along the line It is provided to be movable.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the induction heating apparatus according to the present invention will be described.
[0011]
(A) Embodiment 1
First, FIG. 1 shows the configuration of the induction heating apparatus when a long heat-retaining space is required to keep the temperature for a certain time because the line speed is high. In this case, as shown in the figure, the temperature raising coil 1, the heat retaining means 9, and the cooler 12 are arranged along the line to which the workpiece 4 is transferred, and the heat retaining means 9 includes a single heat retaining cylinder 10 and a single heat retaining cylinder 10. It is comprised with the heat insulation coil 11. FIG.
[0012]
The temperature raising coil 1 is the same as the conventional one and generates heat . The heat retaining cylinder 10 does not generate heat and has a cylindrical shape that covers the periphery of the work in order to prevent the heat of the work from escaping, and is detachably attached to the gantry 13. The heat retaining coil 11 and the cooler 12 that generate heat are configured to be movable along a line by providing wheels 14.
[0013]
In such an induction heating apparatus, the length of the heat retaining space S occupied by the heat retaining means 9 can be freely set by moving the heat retaining coil 11 and the cooler 12 along the line. For this reason, the induction heating of the workpiece | work when a line speed is large and a long heat retention space is required can be performed appropriately.
[0014]
(B) Embodiment 2
Next, FIG. 2 shows the configuration of the induction heating device when a short heat-retaining space is sufficient to keep the temperature for a certain time because the line speed is low. In this case, only the heat retaining coil 11 accompanied by heat generation is provided as the heat retaining means 9 as shown in the figure.
[0015]
Such an induction heating apparatus can be configured by removing the heat retaining cylinder 10 from the line of the first embodiment in FIG. 1 and moving the heat retaining coil 11 and the cooler 12 to the left in the drawing. Since the heat retaining means 9 is configured only by the heat retaining coil 11, the length of the heat retaining space S is short, the line speed is small, and the work can be appropriately induction-heated when a short heat retaining space is required.
[0016]
(C) Embodiment 3
Finally, FIG. 3 shows an induction heating apparatus in the case where the line speed is larger than that in the first embodiment. In this case, FIG. 1 shows that a pair of the heat retaining cylinder 10 and the heat retaining coil 11 is provided as the heat retaining means 9, but two pairs are provided, and the heat retaining space S is lengthened by an amount corresponding to the increase in the workpiece conveyance speed. Thus, the heat retention time is made constant. Note that three or more pairs of the heat retaining cylinders 10 and the heat retaining coils 11 may be provided.
[0017]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0018]
In the first embodiment, one pair of the combination of the heat insulating cylinder and the heat insulating coil is provided as the heat insulating means, and two pairs are provided in the third embodiment. However, three or more pairs may be provided.
[0019]
【The invention's effect】
As can be seen from the above description, according to the induction heating device according to claim 1, the heat retaining means is arranged in order along the flow direction of the line with the heat retaining cylinder for retaining the workpiece without heat generation and the heat retaining coil with heat generation. Since at least one pair of the above combinations is provided, it is possible to properly perform induction heating of the workpiece when the line speed is high and a long heat insulation space is required , compared with the case where the heat insulation coil is arranged in the whole heat insulation space. Manufacturing costs can be reduced .
[0020]
Moreover, since the length of the heat insulation space can be changed, the heat insulation time can be made equal over the entire range from the case where the line speed is low to the case where the line speed is high. By providing a long heat-retaining space, the length between the conveyance rolls that support the workpiece becomes larger than necessary, and adverse effects such as deformation of the workpiece due to its own weight are eliminated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing Embodiment 1 of an induction heating apparatus according to the present invention.
FIG. 2 is a configuration diagram showing a second embodiment of the induction heating apparatus according to the present invention.
FIG. 3 is a configuration diagram showing Embodiment 3 of the induction heating apparatus according to the present invention.
FIG. 4 is a graph showing the relationship between time and temperature when a workpiece is heat-treated.
FIG. 5 is a configuration diagram showing a conventional example 1 of an induction heating device.
FIG. 6 is a configuration diagram showing an electric system in Conventional Example 1 of an induction heating device.
FIG. 7 is a configuration diagram showing a conventional example 2 of an induction heating device.
FIG. 8 is a configuration diagram showing an electrical system in Conventional Example 2 of an induction heating device.
FIG. 9 is a graph for illustrating a defect of Conventional Example 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Temperature rising coil 4 ... Work piece 9 ... Thermal insulation means 10 ... Thermal insulation cylinder 11 ... Thermal insulation coil 12 ... Cooler 14 ... Wheel

Claims

A heating coil that raises the temperature of the workpiece to a predetermined temperature, a heat retaining means that keeps the workpiece at a predetermined temperature, and a cooler that cools the workpiece from the predetermined temperature to room temperature are arranged in order along the line for transferring the workpiece. And
The heat retaining means is configured by providing at least one pair of combinations in which a heat retaining cylinder that retains a work without heat generation and a heat retaining coil with heat generation are sequentially arranged along the line flow direction, and the heat retaining cylinder is on the line while providing detachably to said insulation coil is movable along the line,
An induction heating apparatus, wherein the cooler is provided so as to be movable along a line.