JP2004052074A - Method and apparatus for hardening with laser beam - Google Patents

Method and apparatus for hardening with laser beam Download PDF

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JP2004052074A
JP2004052074A JP2002214081A JP2002214081A JP2004052074A JP 2004052074 A JP2004052074 A JP 2004052074A JP 2002214081 A JP2002214081 A JP 2002214081A JP 2002214081 A JP2002214081 A JP 2002214081A JP 2004052074 A JP2004052074 A JP 2004052074A
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laser
pattern
hardened
hardening
width
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JP3894306B2 (en
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Yusuke Nohara
Keisuke Tsunoda
角田 佳介
野原 祐介
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Toyota Motor Corp
トヨタ自動車株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a new hardening method with laser beam instead of an oscillation system or an integrated system with which uniform hardening can be obtained by controlling heat input in the width direction of a hardening portion of a work. <P>SOLUTION: Two elliptic irradiating patterns P1 ans P2, are combined as V-shape so that respective end parts mutually overlap and two laser beams are scanned to a scanning direction A while preceding the front tip part of this V-shape pattern P3 on the center line in the width direction of the part 2 to be hardened of the platy work 1. Preheating effect is developed to both end parts in the width direction at the part 2 to be hardened by transferring the heat from a side precedingly irradiated to a side irradiated at behind time, and the hardened depths at both end parts are increased. Near the center in the width direction of the part 2 to be hardened, the hardened depth is increased by overlapping two irradiating patterns P1 and P2 and as a result, the hardened layer 3 having almost uniform hardened depths, is formed. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、軸状ワークや板状ワークの表面に焼入れを行うためのレーザ焼入方法とこの方法の実施に用いるレーザ焼入装置に関する。
【0002】
【従来の技術】
例えば、板状ワークの表面にレーザ焼入れを行うには、図8に示すように、ワーク1の被焼入部2の幅に合せてレーザビームの照射パターンPを長円形に設定し、この長円形の照射パターンPを、その長軸がレーザビームの走査方向A(ワーク1の送り方向は、これと反対方向Bとなる)と直交するように配置して、走査方向Aへ平行移動させるようにしている。
【0003】
ところで、レーザ発振源から発振されるレーザビームは、一般に図8の中段に示すように、中央部を最大として周辺部へ向けて急減する指数関数的な断面強度分布(シングルモード)となっており、これに伴って、ワーク1の表層部に形成される硬化層3は、被焼入部2の幅方向中心付近で深く、両端部で浅い焼入パターンとなり、不均一焼入れを避けることはできない。なお、レーザビームの照射パターンPを長円形にする理由は、一度に焼入れできる幅を広げて生産性を上げることにあるが、円形の照射パターンを用いても、前記と同様の問題が生じる。
【0004】
そこで従来、上記不均一焼入れを解消するため、レーザビームの断面強度分布をシングルモードからマルチモードに変更して平均化することが種々行われており、例えば、反射ミラーを揺動させるオシレート方式、あるいはセグメントミラーや異形ミラーで反射させた2つのレーザビームをワーク面上で重合照射させるインテグレーテッド方式などが、既に実施されている(例えば、「機械技術」第36巻第6号第35〜36行、特公昭60−54838号公報等)
【0005】
【発明が解決しようとする課題】
しかしながら、上記オシレート方式やインテグレーテッド方式により実際にレーザ焼入れを行ってみると、レーザビームの断面強度分布が平均化されているにもかかわらず、焼入パターンは、前記図8に示した硬化層3に近似したパターンとなり、不均一焼入を解消することは困難である、という問題があった。また、これらオシレート方式やインテグレーテッド方式では、反射ミラーを揺動させる複雑な機構や特殊ミラーが必要になり、装置が大掛かりになるばかりか高価になる、という問題もあった。
本発明者等は、上記したレーザビームの断面強度分布が平均化されているにもかかわらず不均一焼入れとなる原因について鋭意検討した結果、長円形の照射パターンP(図8)の両端部に相当する被加熱部分では周辺へ熱が逃げ易いのに対し、照射パターンPの中央部に相当する被加熱部分では熱がたまり易いという現象が起き、この現象が焼入深さに影響している、との結論に至った。
一方、本発明者等は、図3に示すようにワーク1に対する照射パターンP1を、走査方向Aに対して傾斜させてレーザビームを走査すると、▲1▼→▲2▼→▲3▼のように時間的に早く照射される側から遅く照射される側へ熱(入熱)が伝わるため、遅く照射される側ほど予熱効果により加熱され易い状態となり、焼入深さは、前記▲1▼→▲2▼→▲3▼の順番に深くなることを見出した。
本発明は、上記した結論並びに知見に基づいてなされたもので、その課題とするところは、ワークの被焼入部の幅方向における入熱を制御することにより均一焼入れを可能にし、もって、オシレート方式やインテグレーテッド方式に代わる新たなレーザ焼入方法を提供し、併せてこの方法の実施に用いて好適なレーザ焼入装置を提供することにある。
【0006】
【課題を解決するための手段】
上記課題を解決するため、本発明に係るレーザ焼入方法は、長円形または長方形の照射パターンを形成する2つのレーザビームを、それぞれの照射パターンがV字形に合わさるようにワーク表面に照射し、このV字形に照射されるパターンの先鋭部を走査方向へ先行または後行させて2つのレーザビームを走査することを特徴とする。
このように行うレーザ焼入れにおいては、V字形に照射されるパターンの先鋭部を走査方向へ先行させてレーザビームを走査すると、該V字形パターンの先鋭部で照射される部分が時間的に早く照射される側、該V字形パターンの開き方向の両端部で照射される部分が時間的に遅く照射される側となるが、2つのレーザビームの照射パターンをV字形パターンの先鋭部で適当に重合させることにより、早く照射される部分の焼入深さを増大させることができ、遅く照射され予熱効果で深く焼きが入る部分との間で焼入深さのアンバランスを解消することができる。
本発明に係るレーザ焼入装置は、レーザ発振源から送られたレーザビームを、長円形または長方形の照射パターンが得られるように整形する光学系を内蔵する2つのレーザトーチを設けた集光装置を備え、該集光装置は、前記2つのレーザトーチをそれぞれの光軸を中心に相対回転させかつ該2つのレーザトーチの相対的な傾きを変更する機構を備えていることを特徴とする。
このように構成したレーザ焼入装置においては、2つのレーザトーチを相対回転させあるいは相互の傾きを変更することで、ワークに照射されるV字形パターンの向き、開き角度等を任意にかつ簡単に調整することができる。
【0007】
【発明の実施の形態】
以下、本発明の実施の形態を添付図面に基づいて説明する。
【0008】
図3および4は、本発明に係るレーザ焼入方法の原理を示したものである。いま、板状ワーク1に対する長円形の照射パターンP1を走査方向Aへ右肩上りに傾斜させた状態でレーザビームを走査すると、図3に示すように、照射パターンP1の、走査方向Aの前側に位置する一端部に対応する右側部位▲1▼が最も早く照射を受けて加熱される。すると、その熱(入熱)は前記部位▲1▼の周辺へ伝わり、その一部は、被焼入部2の幅方向の中央部位▲2▼および左側部位▲3▼へも伝わり、これにより、時間的に遅く照射される部位▲2▼、▲3▼が予熱された状態となる。この予熱効果は、時間的に遅く照射される側ほど高まり、右側部位▲1▼よりも中央部位▲2▼が、中央部位▲2▼よりも左側部位▲3▼がそれぞれ加熱され易い状態となり、この結果、図4の上部左側に示すように、ワーク1に形成される硬化層3aは前記▲1▼→▲2▼→▲3▼の順番に深さを増す焼入パターンとなる。なお、図4の上部右側に示すように、走査方向Aに対して左肩上りに傾斜する照射パターンP2で焼入れを行った場合は、前記硬化層3aと対称的なパターンの硬化層3bとなる。
【0009】
したがって、いま図4の下側に示すように、上記走査方向Aに対する傾斜向きの異なる2つの照射パターンP1と照射パターンP2とを相互に一端部が重合するようにV字形に組合せ、このV字形パターンP3の先鋭部を被焼入部2の幅方向中心上で先行させながら2つのレーザビームを走査すると、V字形パターンP3の先鋭部の移動部位である、被焼入部2の幅方向中心付近が時間的に早く照射される側、被焼入部2の幅方向両端部が時間的に遅く照射される側となる。この場合、V字形パターンP3の先鋭部で各照射パターンP1、P2の一端部が重合していることから、被焼入部2の幅方向中心付近では時間的に早く照射されるにもかかわらず、速やかに加熱され、この結果、被焼入部2の幅方向中心付近と予熱効果により加熱され易い状態となっている被焼入部2の両端部との間で焼入深さにそれほど差がなくなり、幅方向で焼入深さがほぼ均一となる硬化層3が形成される。
【0010】
図1は、本発明に係るレーザ焼入方法の第1の実施の形態を示したものである。本第1の実施の形態においては、上記した原理をそのまま利用して、上記長円形の2つの照射パターンP1とP2とを相互に一端部が重合するようにV字形に組合せ、このV字形パターンP3の先鋭部を板状ワーク1の被焼入部2の幅方向中心線上で先行させながら2つのレーザビームを走査方向Aへ走査させるようにしている。したがって、本第1の実施の形態においては、上記した原理説明の内容と同様の作用で焼入れが進行し、ワーク1の被焼入部2には、その幅方向で焼入れの深さがほぼ一様となる硬化層3が形成される。なお、前記照射パターンP1とP2は、長円形に代えて長方形としてもよいことはもちろんである。
【0011】
ここで、上記レーザ焼入方法を実施するためのレーザ焼入装置は、一例として図2に示すように構成されている。同図において、11、12はレーザ発振器(レーザ発振源)、13、14は、対応するレーザ発振器11、12から光ファイバ15、16を経て送られたレーザビームを集光しワーク1へ向けて照射する2つのレーザトーチ、17は前記2つのレーザトーチ13、14を含む集光装置である。各レーザトーチ13、14は、レーザ発振器11、12から送られたレーザビームを、前記長円形の照射パターンP1、P2(図1、図4)が得られるように整形する光学系を内蔵している。一方、集光装置17は、各レーザトーチ13、14を、それぞれの光軸O1、O2を中心に相対回転させる回転機構と、各レーザトーチ13、14の相対的な傾き(交差度)を調整する傾動機構とを内蔵している。
【0012】
上記集光装置17は、例えば昇降台18に支持され、レーザ焼入に際しては、搬送装置19上に搭載されたワーク1に対して所定の高さレベルに位置決めされる。このとき、集光装置17内の2つのレーザトーチ13、14は、それぞれの照射パターンP1、P2により上記第1の実施の形態におけるV字形パターンP3(図1)がワーク1の表面に形成されるように、相互に回転方向に位置決めされかつ傾斜角度が調整されている。この状態のもと、レーザ発振器11、12から対応するレーザトーチ13、14へレーザビームを送り、かつ搬送装置19によりワーク1を走査方向Aと逆方向B(図1)へ送ると、前記V字形パターンP3の先鋭部が照射方向Aの前側に位置する状態すなわち先行する状態でV字形パターンP3が走査方向Aへ進み、これにより上記第1の実施の形態におけるレーザ焼入方法が実施されることとなり、ワーク1の表層部には均一な硬化層3が形成される。
なお、上記集光装置17においては、2つのレーザトーチ13、14に対し、対応するレーザ発振器11、12から各独立にレーザビームを送るようにしたが、これに代えて、1つのレーザ発振源を共用して該レーザ発振源からのレーザビームを2系統に分割してレーザトーチ13、14へ送るようにしてもよい。また、この集光装置17は、産業用ロボットに支持させるようにしてもよく、この場合は、ワーク1の位置を固定して集光装置17(レーザトーチ13、14)を照射方向Aへ移動させることができる。
【0013】
上記第1の実施の形態において、ワーク1の表面に形成するV字パターンP3の形態は任意であり、例えば、図5(A)に示すように、2つのレーザビームにより形成される長円形の照射パターンP1とP2とをクロスさせたV字パターンP3´とし、あるいは同図(B)に示すように2つのレーザビームにより形成される長円形の照射パターンP1とP2との合せ部をわずか離したV字形パターンP3″としてもよい。クロスさせたV字パターンP3´としてその先鋭部を先行させた場合は、第1の実施の形態で得られる硬化層3に対して、被焼入部2の幅方向中心付近でわずか焼入深さが深くなる焼入パターンが得られ、一方、わずか離したV字形パターンP3″としてその先鋭部を先行させた場合は、第1の実施の形態で得られる硬化層3に対して、被焼入部2の幅方向中心付近でわずか焼入深さが浅くなる焼入パターンが得られるようになる。
【0014】
図6は、本発明に係るレーザ焼入方法の第2の実施の形態を示したものである。本第2の実施の形態の特徴とするところは、上記第1の実施の形態におけるV字形パターンP3を、レーザビームの走査方向Aに対して逆向きに設定して、その先鋭部を後行させる状態で2つのレーザビームを走査方向Aへ走査させるようにした点にある。
本第2の実施の形態においては、V字形パターンP3の先鋭部の移動部位である、被焼入部2の幅方向中心付近が時間的に遅く照射される側、被焼入部2の幅方向両端部が時間的に早く照射される側となり、予熱効果により被焼入部2の幅方向中心付近でより深く焼きが入る。この場合、V字形パターンP3の先鋭部で各照射パターンP1、P2の一端部が重合していることから、被焼入部2の幅方向中心付近はより加熱され易い状態となり、この結果、図6の下側に示すように、ワーク1に形成される硬化層3´は、被焼入部2の幅方向中心付近で深さが極大となる山形の焼入パターンとなる。
【0015】
図7は、本発明に係るレーザ焼入方法の第3の実施の形態を示したものである。本第3の実施の形態の特徴とするところは、軸状ワーク20を対象にその周面に上記第1の実施の形態におけるV字形パターンP3が形成されるように2つのレーザビームを照射し、ワーク20の回転に応じてその円周方向へV字形パターンP3を移動させるようにした点にある。この場合、ワーク20を左回転または右回転させることで、V字形パターンP3の先鋭部が走査方向へ先行または後行する状態で焼入れが進行し、これにより、ワーク20の表層部には、上記第1の実施の形態で得られるような均一な焼入パターンを有する硬化層3、あるいは上記第2の実施の形態で得られるような山形の焼入パターンを有する硬化層3´が形成される。
【0016】
【実施例】
上記第3の実施の形態で用いた軸状ワーク20(図7)を対象に、該ワーク20として、JIS S45C製で直径33mm、長さ63.3mmの大きさのものを選択し、前記図2に示したレーザ焼入装置により、そのレーザ発振器11、12としてLD励起YAG発振器を用いて、ワーク20の表面に前記V字形パターンP3を形成し、このV字形パターンP3の先鋭部が照射方向へ先行するようにワーク20を回転させた。この際、V字形パターンP3を構成する各照射パターンP1、P2は、長軸が18mm、短軸が4mmとなるようにその大きさを設定すると共に、V字形パターンP3の全幅(広がり)を20mmに設定し、レーザ出力950W、ワーク20の回転速度6rpmの条件でワーク20を10秒で一回転させ、その全周にレーザ焼入れを行った。そして、この焼入後、ワークWを切断して試験片を採取し、その被検面を研磨した後、エッチングを行って硬化層を観察した。この結果、ワーク20の表層部には、V字形パターンP3の全幅にほぼ等しい20mm幅にわたって、ほぼ一様な深さ0.3mmとなる硬化層が観察され、本発明の方法が均一焼入れにきわめて有用であることを確認できた。
【0017】
【発明の効果】
以上、説明したように、本発明に係るレーザ焼入方法および装置によれば、2つのレーザビームの照射パターンをV字形に組合せて、走査方向を選択するだけで、均一焼入れが可能になるので、従来のオシレート方式やインテグレーテッド方式に代わるレーザ焼入方法として、きわめて有用となる。
【図面の簡単な説明】
【図1】本発明の第1の実施の形態としてのレーザ焼入方法の実施状況と実施後の硬化層の状態とを示す模式図である。
【図2】本第1の実施の形態で用いるレーザ焼入装置を示す模式図である。
【図3】本発明に係るレーザ焼入方法の原理を示す模式図である。
【図4】本発明に係るレーザ焼入方法の原理を示す模式図である。
【図5】第1の実施の形態の変形例を示す模式図である。
【図6】本発明の第2の実施の形態としてのレーザ焼入方法の実施状況と実施後の硬化層の状態とを示す模式図である。
【図7】本発明の第3の実施の形態としてのレーザ焼入方法の実施状況を模式的に示す斜視図である。
【図8】従来のレーザ焼入方法の実施状況と実施後の硬化層の状態とを示す模式図である。
【符号の説明】
1  板状ワーク
2  被焼入部
3  硬化層
11、12 レーザ発振器(レーザ発振源)
13、14 レーザトーチ
17 集光装置
20 軸状ワーク
P1、P2 各レーザビームの照射パターン
P3 V字形パターン
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser quenching method for quenching the surface of a shaft-like workpiece or a plate-like workpiece, and a laser quenching apparatus used for carrying out this method.
[0002]
[Prior art]
For example, in order to perform laser hardening on the surface of a plate-like workpiece, as shown in FIG. 8, the irradiation pattern P of the laser beam is set to an oval according to the width of the portion to be hardened 2 of the workpiece 1, and this oval is formed. The irradiation pattern P is arranged so that its long axis is perpendicular to the scanning direction A of the laser beam (the feed direction of the workpiece 1 is the opposite direction B), and is translated in the scanning direction A. ing.
[0003]
By the way, the laser beam oscillated from the laser oscillation source generally has an exponential cross-sectional intensity distribution (single mode) that rapidly decreases toward the peripheral portion with the maximum at the central portion as shown in the middle part of FIG. Accordingly, the hardened layer 3 formed on the surface layer portion of the workpiece 1 has a deep quenching pattern near the center in the width direction of the to-be-quenched portion 2 and a shallow quenching pattern at both end portions, and uneven quenching cannot be avoided. The reason for making the laser beam irradiation pattern P oval is to increase the width that can be quenched at one time to increase productivity, but the same problem as described above occurs even if a circular irradiation pattern is used.
[0004]
Therefore, conventionally, in order to eliminate the non-uniform quenching, the laser beam cross-sectional intensity distribution has been variously averaged by changing from a single mode to a multimode. For example, an oscillating method of swinging a reflecting mirror, Alternatively, an integrated system in which two laser beams reflected by a segment mirror or a deformed mirror are superposed on the work surface is already implemented (for example, “Machine Technology” Vol. 36, No. 6, No. 35-36). Line, JP-B 60-54838)
[0005]
[Problems to be solved by the invention]
However, when laser quenching is actually performed by the oscillating method or the integrated method, the hardened pattern shown in FIG. 8 is obtained even though the cross-sectional intensity distribution of the laser beam is averaged. There was a problem that it was difficult to eliminate non-uniform quenching. In addition, these oscillating methods and integrated methods require a complicated mechanism and a special mirror for swinging the reflecting mirror, and there is a problem that the apparatus becomes large and expensive.
As a result of intensive studies on the cause of non-uniform quenching despite the above-described cross-sectional intensity distribution of the laser beam being averaged, the present inventors have found that the both ends of the oval irradiation pattern P (FIG. 8). In the corresponding heated portion, heat easily escapes to the periphery, whereas in the heated portion corresponding to the central portion of the irradiation pattern P, a phenomenon occurs in which heat tends to accumulate, and this phenomenon affects the quenching depth. I came to the conclusion.
On the other hand, when the present inventors scan the laser beam while inclining the irradiation pattern P1 on the workpiece 1 with respect to the scanning direction A as shown in FIG. 3, as shown in (1) → (2) → (3) Since heat (heat input) is transmitted from the side that is irradiated earlier in time to the side that is irradiated later in time, the later irradiated side is more easily heated by the preheating effect, and the quenching depth is the above-mentioned (1) I found out that it becomes deeper in the order of (2)-> (3).
The present invention has been made on the basis of the above conclusions and findings, and the object of the present invention is to enable uniform quenching by controlling the heat input in the width direction of the workpiece to be quenched, and thus the oscillating method. And a new laser quenching method that replaces the integrated method and a laser quenching apparatus suitable for use in the implementation of this method.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the laser hardening method according to the present invention irradiates the surface of a workpiece with two laser beams forming an oval or rectangular irradiation pattern so that each irradiation pattern matches a V shape, Two laser beams are scanned by making the sharpened portion of the pattern irradiated in the V shape precede or follow in the scanning direction.
In laser hardening performed in this way, when the laser beam is scanned with the sharpened portion of the pattern irradiated in a V-shape preceding the scanning direction, the portion irradiated with the sharpened portion of the V-shaped pattern is irradiated earlier in time. The side irradiated with both ends in the opening direction of the V-shaped pattern is the side irradiated with time, but the two laser beam irradiation patterns are appropriately overlapped with the sharp part of the V-shaped pattern. By doing so, the quenching depth of the portion irradiated early can be increased, and the imbalance of the quenching depth between the portion irradiated late and deeply quenched by the preheating effect can be eliminated.
A laser hardening apparatus according to the present invention includes a condensing apparatus provided with two laser torches incorporating an optical system for shaping a laser beam sent from a laser oscillation source so as to obtain an oval or rectangular irradiation pattern. The condensing device includes a mechanism that relatively rotates the two laser torches about the respective optical axes and changes a relative inclination of the two laser torches.
In the laser hardening apparatus configured in this way, the orientation and opening angle of the V-shaped pattern irradiated on the workpiece can be adjusted arbitrarily and easily by rotating the two laser torches or changing their inclinations. can do.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0008]
3 and 4 show the principle of the laser hardening method according to the present invention. Now, when the laser beam is scanned in a state where the oval irradiation pattern P1 for the plate-like workpiece 1 is inclined to the right in the scanning direction A, as shown in FIG. 3, the front side of the irradiation pattern P1 in the scanning direction A The right side portion {circle around (1)} corresponding to the one end located at the first is irradiated and heated the fastest. Then, the heat (heat input) is transmitted to the periphery of the part (1), and a part thereof is also transmitted to the central part (2) and the left part (3) in the width direction of the portion to be hardened 2, thereby The portions {circle around (2)} and {circle around (3)} that are irradiated later in time are in a preheated state. This preheating effect increases as the side irradiated later in time, and the central part (2) is more easily heated than the right part (1), and the left part (3) is more easily heated than the central part (2). As a result, as shown on the upper left side of FIG. 4, the hardened layer 3a formed on the workpiece 1 has a quenching pattern in which the depth increases in the order of (1) → (2) → (3). In addition, as shown in the upper right side of FIG. 4, when hardening is performed with the irradiation pattern P2 which inclines to the left shoulder with respect to the scanning direction A, it becomes the hardened layer 3b of a symmetrical pattern with the hardened layer 3a.
[0009]
Therefore, as shown in the lower side of FIG. 4, the two irradiation patterns P1 and P2 having different inclination directions with respect to the scanning direction A are combined in a V shape so that one end portions overlap each other. When two laser beams are scanned while the sharp part of the pattern P3 is advanced on the center of the hardened part 2 in the width direction, the vicinity of the center of the hardened part 2 in the width direction, which is the moving part of the sharp part of the V-shaped pattern P3, is found. The side that is irradiated earlier in time and the both ends in the width direction of the hardened portion 2 are the sides that are irradiated later in time. In this case, since one end part of each irradiation pattern P1, P2 is superposed at the sharp part of the V-shaped pattern P3, although it is irradiated early in the vicinity of the width direction center of the to-be-quenched part 2, It is quickly heated, and as a result, there is not much difference in the quenching depth between the vicinity of the center in the width direction of the portion to be quenched 2 and both ends of the portion to be quenched 2 that is easily heated by the preheating effect, A hardened layer 3 having a substantially uniform quenching depth in the width direction is formed.
[0010]
FIG. 1 shows a first embodiment of a laser hardening method according to the present invention. In the first embodiment, the above-described principle is used as it is, and the two oval irradiation patterns P1 and P2 are combined in a V shape so that one end thereof is overlapped with each other. The two laser beams are scanned in the scanning direction A while the sharp portion of P3 is advanced on the center line in the width direction of the portion to be hardened 2 of the plate-like workpiece 1. Accordingly, in the first embodiment, quenching proceeds by the same action as described in the principle description above, and the quenching depth of the workpiece 1 to be quenched 2 is substantially uniform in the width direction. A cured layer 3 is formed. Of course, the irradiation patterns P1 and P2 may be rectangular instead of oval.
[0011]
Here, a laser hardening apparatus for carrying out the laser hardening method is configured as shown in FIG. 2 as an example. In the figure, reference numerals 11 and 12 denote laser oscillators (laser oscillation sources), and reference numerals 13 and 14 denote laser beams sent from the corresponding laser oscillators 11 and 12 via optical fibers 15 and 16 and are directed toward the work 1. Two laser torches 17 and 17 to irradiate are condensing devices including the two laser torches 13 and 14. Each of the laser torches 13 and 14 incorporates an optical system that shapes the laser beam sent from the laser oscillators 11 and 12 so as to obtain the elliptical irradiation patterns P1 and P2 (FIGS. 1 and 4). . On the other hand, the condensing device 17 tilts to adjust the relative inclination (crossing degree) of the laser torches 13 and 14 and the rotation mechanism that relatively rotates the laser torches 13 and 14 around the optical axes O1 and O2. Built-in mechanism.
[0012]
The condensing device 17 is supported by, for example, a lift 18 and is positioned at a predetermined height level with respect to the workpiece 1 mounted on the transport device 19 during laser quenching. At this time, the two laser torches 13 and 14 in the light condensing device 17 form the V-shaped pattern P3 (FIG. 1) in the first embodiment on the surface of the workpiece 1 by the respective irradiation patterns P1 and P2. As described above, they are positioned in the rotational direction and the inclination angle is adjusted. In this state, when the laser beam is sent from the laser oscillators 11 and 12 to the corresponding laser torches 13 and 14 and the workpiece 1 is sent in the direction B opposite to the scanning direction A (FIG. 1) by the conveying device 19, the V-shaped. The V-shaped pattern P3 advances in the scanning direction A in a state where the sharpened portion of the pattern P3 is positioned in front of the irradiation direction A, that is, in a preceding state, and thereby the laser hardening method in the first embodiment is performed. Thus, a uniform hardened layer 3 is formed on the surface layer portion of the work 1.
In the condensing device 17, the laser beams are independently sent from the corresponding laser oscillators 11 and 12 to the two laser torches 13 and 14, but instead of this, one laser oscillation source is provided. In common, the laser beam from the laser oscillation source may be divided into two systems and sent to the laser torches 13 and 14. Further, the light collecting device 17 may be supported by an industrial robot. In this case, the position of the workpiece 1 is fixed and the light collecting device 17 (laser torches 13 and 14) is moved in the irradiation direction A. be able to.
[0013]
In the first embodiment, the shape of the V-shaped pattern P3 formed on the surface of the workpiece 1 is arbitrary. For example, as shown in FIG. 5A, an oval formed by two laser beams. A V-shaped pattern P3 ′ obtained by crossing the irradiation patterns P1 and P2 or, as shown in FIG. 5B, the joining portion of the oval irradiation patterns P1 and P2 formed by two laser beams is slightly separated. The V-shaped pattern P3 ″ may be used. When the sharpened portion is preceded as the crossed V-shaped pattern P3 ′, the hardened layer 2 obtained in the first embodiment has A quenching pattern having a slightly deepened quenching depth in the vicinity of the center in the width direction is obtained. On the other hand, when the sharpened portion is preceded as a slightly separated V-shaped pattern P3 ″, it is obtained in the first embodiment. Hardened layer 3, a quenching pattern in which the quenching depth becomes slightly shallow near the center in the width direction of the portion to be quenched 2 can be obtained.
[0014]
FIG. 6 shows a second embodiment of the laser hardening method according to the present invention. The feature of the second embodiment is that the V-shaped pattern P3 in the first embodiment is set in the opposite direction with respect to the scanning direction A of the laser beam, and the sharpened portion is followed. In this state, two laser beams are scanned in the scanning direction A.
In the second embodiment, the side near the center in the width direction of the to-be-quenched portion 2 which is the moving part of the sharp portion of the V-shaped pattern P3 is irradiated with time later, both ends in the width direction of the to-be-quenched portion 2 The portion becomes the side that is irradiated earlier in time, and deeper quenching occurs near the center in the width direction of the portion to be quenched 2 due to the preheating effect. In this case, since one end of each irradiation pattern P1, P2 is superposed at the sharp part of the V-shaped pattern P3, the vicinity of the center in the width direction of the to-be-quenched part 2 is more easily heated. As a result, FIG. As shown on the lower side, the hardened layer 3 ′ formed on the work 1 has a chevron-shaped quenching pattern in which the depth is maximized near the center in the width direction of the portion to be quenched 2.
[0015]
FIG. 7 shows a third embodiment of the laser hardening method according to the present invention. The feature of the third embodiment is that two laser beams are irradiated so that the V-shaped pattern P3 in the first embodiment is formed on the peripheral surface of the shaft-like workpiece 20 as an object. The V-shaped pattern P3 is moved in the circumferential direction according to the rotation of the workpiece 20. In this case, by rotating the work 20 counterclockwise or clockwise, quenching proceeds with the sharpened portion of the V-shaped pattern P3 leading or following in the scanning direction. A cured layer 3 having a uniform quenching pattern as obtained in the first embodiment, or a cured layer 3 ′ having a chevron-shaped quenching pattern as obtained in the second embodiment is formed. .
[0016]
【Example】
For the shaft-like workpiece 20 (FIG. 7) used in the third embodiment, the workpiece 20 made of JIS S45C and having a diameter of 33 mm and a length of 63.3 mm is selected. 2 is used to form the V-shaped pattern P3 on the surface of the workpiece 20 by using an LD-excited YAG oscillator as the laser oscillators 11 and 12, and the sharp portion of the V-shaped pattern P3 is irradiated in the irradiation direction. The workpiece 20 was rotated so as to precede. At this time, the irradiation patterns P1 and P2 constituting the V-shaped pattern P3 are sized so that the major axis is 18 mm and the minor axis is 4 mm, and the total width (expansion) of the V-shaped pattern P3 is 20 mm. The workpiece 20 was rotated once in 10 seconds under the conditions of a laser output of 950 W and a rotational speed of the workpiece 20 of 6 rpm, and laser hardening was performed on the entire circumference. And after this hardening, after cut | disconnecting the workpiece | work W, the test piece was extract | collected, the test surface was grind | polished, and it etched, and observed the hardened layer. As a result, a hardened layer having a substantially uniform depth of 0.3 mm is observed in the surface layer portion of the work 20 over a 20 mm width substantially equal to the entire width of the V-shaped pattern P3, and the method of the present invention is extremely effective for uniform quenching. It was confirmed that it was useful.
[0017]
【The invention's effect】
As described above, according to the laser quenching method and apparatus according to the present invention, uniform quenching can be achieved simply by combining the irradiation patterns of the two laser beams into a V shape and selecting the scanning direction. It is extremely useful as a laser hardening method that replaces the conventional oscillating method and integrated method.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an implementation status of a laser hardening method as a first embodiment of the present invention and a state of a cured layer after implementation.
FIG. 2 is a schematic diagram showing a laser hardening apparatus used in the first embodiment.
FIG. 3 is a schematic diagram showing the principle of a laser hardening method according to the present invention.
FIG. 4 is a schematic diagram showing the principle of a laser hardening method according to the present invention.
FIG. 5 is a schematic diagram showing a modification of the first embodiment.
FIG. 6 is a schematic diagram showing a state of implementation of a laser hardening method as a second embodiment of the present invention and a state of a cured layer after implementation.
FIG. 7 is a perspective view schematically showing an implementation status of a laser hardening method as a third embodiment of the present invention.
FIG. 8 is a schematic diagram showing the state of implementation of a conventional laser hardening method and the state of the cured layer after implementation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plate-shaped workpiece 2 Hardened part 3 Hardened layer 11, 12 Laser oscillator (laser oscillation source)
13, 14 Laser torch 17 Condensing device 20 Axial workpiece P1, P2 Irradiation pattern P3 of each laser beam P3 V-shaped pattern

Claims (3)

  1. 長円形または長方形の照射パターンを形成する2つのレーザビームを、それぞれの照射パターンがV字形に合わさるようにワーク表面に照射し、このV字形に照射されるパターンの先鋭部を走査方向へ先行または後行させて2つのレーザビームを走査することを特徴とするレーザ焼入方法。Two laser beams forming an oval or rectangular irradiation pattern are irradiated on the surface of the workpiece so that each irradiation pattern is aligned with a V shape, and a sharp portion of the pattern irradiated in the V shape is advanced in the scanning direction or A laser quenching method, wherein the two laser beams are scanned in a subsequent manner.
  2. 2つのレーザビームの照射パターンをV字形パターンの先鋭部で重合させ、該V字形パターンの先鋭部を走査方向へ先行させることを特徴とする請求項1に記載のレーザ焼入方法。2. The laser hardening method according to claim 1, wherein two laser beam irradiation patterns are superposed at a sharp portion of a V-shaped pattern, and the sharp portion of the V-shaped pattern is advanced in a scanning direction.
  3. レーザ発振源から送られたレーザビームを、長円形または長方形の照射パターンが得られるように整形する光学系を内蔵する2つのレーザトーチを設けた集光装置を備え、該集光装置は、前記2つのレーザトーチをそれぞれの光軸を中心に相対回転させ、かつ該2つのレーザトーチの相対的な傾きを変更する機構を備えていることを特徴とするレーザ焼入装置。A condensing device provided with two laser torches incorporating an optical system that shapes a laser beam sent from a laser oscillation source so as to obtain an oval or rectangular irradiation pattern, and the condensing device includes the 2 A laser hardening apparatus comprising a mechanism for rotating two laser torches relative to each other along an optical axis and changing a relative inclination of the two laser torches.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013010876A1 (en) * 2011-07-15 2013-01-24 Fraunhofer-Ges. Zur Förderung Der Angewandten Forschung E.V. Process and apparatus for smoothing and polishing workpiece surfaces by machining with two energetic radiations
CN103602790A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process of sliding plate
CN103602789A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process for effective control of quenching deformation of sliding plate
CN103602800A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process of sliding plate
CN103602788A (en) * 2012-05-27 2014-02-26 蒋超 Sliding plate laser strengthening process for laser quenching on sliding plate surface
WO2020064635A1 (en) * 2018-09-24 2020-04-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Method for smoothing the surface of a plastic component

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013010876A1 (en) * 2011-07-15 2013-01-24 Fraunhofer-Ges. Zur Förderung Der Angewandten Forschung E.V. Process and apparatus for smoothing and polishing workpiece surfaces by machining with two energetic radiations
CN103602790A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process of sliding plate
CN103602789A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process for effective control of quenching deformation of sliding plate
CN103602800A (en) * 2012-05-27 2014-02-26 蒋超 Laser strengthening process of sliding plate
CN103602788A (en) * 2012-05-27 2014-02-26 蒋超 Sliding plate laser strengthening process for laser quenching on sliding plate surface
WO2020064635A1 (en) * 2018-09-24 2020-04-02 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Method for smoothing the surface of a plastic component

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