JP4009432B2 - Laser welding method for vehicular lamp - Google Patents

Laser welding method for vehicular lamp Download PDF

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Publication number
JP4009432B2
JP4009432B2 JP2001096075A JP2001096075A JP4009432B2 JP 4009432 B2 JP4009432 B2 JP 4009432B2 JP 2001096075 A JP2001096075 A JP 2001096075A JP 2001096075 A JP2001096075 A JP 2001096075A JP 4009432 B2 JP4009432 B2 JP 4009432B2
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lens
welding
laser
laser light
end portion
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JP2002292741A (en
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秀生 中村
正孝 浅井
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Toyota Motor Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B29C66/543—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles joining more than two hollow-preforms to form said hollow articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1635—Laser beams characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. laser transmission welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1654—Laser beams characterised by the way of heating the interface scanning at least one of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B29C65/1677—Laser beams making use of an absorber or impact modifier
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
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    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1246—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove
    • B29C66/12463—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove being tapered
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    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
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    • B29C66/545—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles one hollow-preform being placed inside the other
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    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
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    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1603—Laser beams characterised by the type of electromagnetic radiation
    • B29C65/1612—Infrared [IR] radiation, e.g. by infrared lasers
    • B29C65/1616—Near infrared radiation [NIR], e.g. by YAG lasers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/739—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • B29C66/73921—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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    • B29K2033/04—Polymers of esters
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    • B29K2055/00—Use of specific polymers obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of main groups B29K2023/00 - B29K2049/00, e.g. having a vinyl group, as moulding material
    • B29K2055/02—ABS polymers, i.e. acrylonitrile-butadiene-styrene polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B29K2067/006—PBT, i.e. polybutylene terephthalate
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    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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    • B29K2069/00—Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
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    • F21V17/101—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening permanently, e.g. welding, gluing or riveting

Description

【０００１】
【発明の属する技術分野】
本発明は車両用灯具のレーザ溶着方法に関し、詳しくはレーザ溶着を利用してレンズとボディとを一体的に接合する車両用灯具のレーザ溶着方法に関する。
【０００２】
【従来の技術】
自動車のヘッドライト等の車両用灯具は、一般に、レンズと、ランプ及びリフレクタ（反射鏡）を保持するボディとが一体的に接合された構造となっている。このレンズとボディとの接合方法として、特開２０００−２９４０１２号公報には、レーザ溶着を利用する方法が開示されている。
【０００３】
レーザ溶着によるレンズとボディとの接合では、加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディとの当接端部同士を重ね合わせ、ボディの当接端部に向けてレンズ側からレーザ光を照射する。これにより、レンズを透過したレーザ光がボディの当接端部に到達して吸収され、この当接端部に吸収されたレーザ光がエネルギーとして蓄積される。その結果、ボディの当接端部が加熱溶融されるとともに、このボディの当接端部からの熱伝達によりレンズの当接端部が加熱溶融される。この状態で、レンズ及びボディの当接端部同士を圧着させれば、両者を一体的に接合することができる。
【０００４】
そして、上記特開２０００−２９４０１２号公報に開示された車両用灯具では、上記レンズの材質として、透明性、耐熱性や強度等の観点から、ＰＣ（ポリカーボネート）やＰＭＭＡ（ポリメタクリル酸メチル）等が用いられており、また上記ボディの材質として、耐熱性や強度等の観点から、ＰＣを含むポリマーアロイ、具体的にはＰＣとＡＡＳ（アクリル・アクリロニトリル・スチレンポリマー）、ＰＣとＡＢＳ（アリクロニトリル・ブタジエン・スチレンポリマー）、ＰＣとＰＥＴ（ポリエチレンテレフタレート）又はＰＣとＰＢＴ（ポリブチレンテレフタレート）等のポリマーアロイ等が用いられている。
【０００５】
【発明が解決しようとする課題】
ところで、レンズ及びボディに用いられるＰＣ自体は、一般に、レーザ光の透過率が８０〜９５％程度あり、また衝撃強さ、耐熱性及び寸法安定性等に優れている。しかし、このＰＣは、ある一定のストレスレベルを超えるとクラック（ストレスクラック）が発生し易いという特性を有する。そして、このストレスクラックは、熱影響部（溶融はしていないが、組織や機械的性質が変化した部分）や熱劣化した部分等で特に発生し易い。
【０００６】
このため、ＰＣ製レンズに対して、ＰＣを含むポリマーアロイからなるボディをレーザ溶着する場合、以下に示すようにボディ側にストレスクラックが発生し易く、またこのストレスクラックの発生を抑制することが困難であるため、ボディの強度面における信頼性が低下するという問題がある。
【０００７】
すなわち、レーザ透過側のレンズは、レーザ溶着時、ＰＣの高透過性によりレーザ透過中におけるレーザ吸収による内部発熱がほとんどなく、レーザ吸収側のボディからの熱伝達のみで加熱溶融され、しかもボディとの界面のみが溶融して溶着する。このため、レーザ透過側のレンズにおいては、熱影響部がほとんどなく（勿論、熱劣化もしていない）、ストレスクラックがほとんど発生しない。
【０００８】
一方、レーザ吸収側のボディにおいては、レーザ光の吸収により直接加熱溶融されるとともに、ＰＣ製レンズにおける高透過性によりレーザ照射による熱的影響を大きく、かつ、敏感に受けることから、急激な温度上昇や入熱過大が発生し易く、熱影響部の形成や熱劣化の発生を抑えることが困難となる。このため、ボディにＰＣが含まれていると、ストレスクラックが発生し易くなる。
【０００９】
ここに、上記ボディの溶着面における急激な温度上昇や入熱過大は、レーザの照射条件、例えばレーザの出力、照射密度や加工速度（移動速度）等を適宜設定することにより、ある程度は回避することができる。しかし、上述のとおりボディの溶着面はレーザ照射による熱的影響を大きく、かつ、敏感に受けることから、照射条件の小さな調整ミスや操作ミス等の影響を諸に受け、かかる調整ミス等があるとボディの溶着面温度が大きく変化してしまう。このため、単純な照射条件の調整によっては、ボディ溶着面における急激な温度上昇や入熱過大を確実に回避することが困難となり、したがってボディのストレスクラック発生を効果的に抑制することが困難となる。
【００１０】
本発明は上記実情に鑑みてなされたものであり、ＰＣ製レンズに対してボディをレーザ溶着する場合に、ボディにおけるストレスクラックの発生を抑制しうる車両用灯具のレーザ溶着方法を提供することを解決すべき技術課題とするものである。
【００１１】
【課題を解決するための手段】
上記課題を解決する請求項１記載の車両用灯具のレーザ溶着方法は、加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディとの当接端部同士を当接させる当接工程と、
上記レンズ側からの上記レーザ光の照射により、上記レンズの当接端部及び上記ボディの当接端部の各溶着面同士を加熱溶融させて溶着し、該レンズと該ボディとを一体的に接合する照射工程とからなる車両用灯具のレーザ溶着方法であって、
上記レンズはＰＣ材からなるとともに上記ボディはＰＣ系材からなり、かつ、該レンズの当接端部は嵌合凸部により構成されるとともに、該ボディの当接端部は該嵌合凸部と嵌合可能な嵌合凹部により構成され、
上記当接工程では、該嵌合凸部と該嵌合凹部とを嵌合させ、上記照射工程では、該ボディの当接端部の溶着面である該嵌合凹部の内面のうちの少なくとも一部に対して上記レーザ光を斜め照射することを特徴とするものである。
【００１２】
ここに、レーザ光を斜め照射するとは、レーザ光の入射角が０度を超え、かつ、９０度未満であることを意味する。
【００１５】
上記課題を解決する請求項２記載の車両用灯具のレーザ溶着方法は、加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディと、該レーザ光に対して吸収性のある吸収性樹脂材からなるリフレクタとの当接端部同士を当接させる当接工程と、
上記レンズ側からの上記レーザ光の照射により、上記レンズの当接端部、上記ボディの当接端部及び上記リフレクタの当接端部の各溶着面を加熱溶融させて溶着し、該レンズ、該ボディ及び該リフレクタを一体的に接合する照射工程とからなる車両用灯具のレーザ溶着方法であって、
上記レンズはＰＣ材からなり、上記ボディはＡＢＳ系材からなり、上記リフレクタはＰＥＴ系材又はＰＢＴ系材からなり、
上記照射工程では、上記レンズ側から上記リフレクタの上記当接端部の溶着面に向けて上記レーザ光を照射するとともに、該溶着面で反射したレーザ光を上記レンズの上記当接端部内を透過させて上記ボディの上記当接端部の溶着面に到達させることにより、該レンズ及び該リフレクタ同士並びに該レンズ及び該ボディ同士を溶着することを特徴とするものである。
【００１６】
【発明の実施の形態】
請求項１に記載の車両用灯具のレーザ溶着方法は、加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディとの当接端部同士を当接させる当接工程と、該レンズ側からのレーザ光の照射により、該レンズの当接端部及び該ボディの当接端部の各溶着面同士を加熱溶融させて溶着し、該レンズと該ボディとを一体的に接合する照射工程とからなる。この照射工程において、レンズ側から照射されたレーザ光は該レンズ内を透過してボディの当接端部の溶着面に到達し、吸収される。このボディの溶着面に吸収されたレーザ光がエネルギーとして蓄積される結果、ボディの溶着面が加熱溶融されるとともに、このボディの溶着面からの熱伝達によりレンズの当接端部の溶着面が加熱溶融される。この状態で、レンズ及びボディの溶着面同士を圧着させれば、両者を一体的に接合することができる。
【００１７】
こうして得られた接合部では、溶着面同士が溶融されて接合されており、該溶着面同士の間では両部材を構成する両樹脂が溶融して互いに入り込み絡まった状態が形成されているため、強固な接合状態を構成して高い接合強度及び耐圧強度を有している。
【００１８】
ここに、請求項１記載の車両用灯具のレーザ溶着方法では、上記レンズはＰＣ材からなるとともに上記ボディはＰＣ系材からなり、かつ、該レンズの当接端部は嵌合凸部により構成されるとともに、該ボディの当接端部は該嵌合凸部と嵌合可能な嵌合凹部により構成され、上記当接工程では、該嵌合凸部と該嵌合凹部とを嵌合させ、上記照射工程では、該ボディの当接端部の溶着面である該嵌合凹部の内面のうちの少なくとも一部に対して上記レーザ光を斜め照射することを特徴とする。
【００１９】
上記ボディを構成するＰＣ系材とは、ＰＣ単独からなるＰＣ材（レーザ光に対する所定の吸収性を付与すべく着色材が添加されたもの）、又はＰＣを含むアロイ材を意味する。アロイ材におけるＰＣの相手材としては、ＡＡＳ、ＡＢＳ、ＰＢＴ、ＰＥＴ、ＰＭＭＡ、ＰＡ（ポリアミド）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）やエラストマー等を挙げることができる。なお、ＰＣ系材からなるボディには、レーザ光に対して所定の吸収性を有する吸収性樹脂材とすべく、必要に応じて、カーボンブラック、染料や顔料等の所定の着色材を混入することができ、また必要に応じて、ガラス繊維やカーボン繊維等の補強繊維を添加してもよい。
【００２０】
そして、上記照射工程で、レーザ光を斜め照射することにより、ボディにおけるストレスクラックの発生を容易、かつ、効果的に抑制することが可能となる。
【００２１】
すなわち、ボディの溶着面に対してレーザ光を斜め照射（以下、単に「斜め照射」という）する場合は、該溶着面に対して垂直方向から照射（以下、単に「垂直照射」という）する場合と比較して、該溶着面で反射するレーザ光が多くなる分だけ、該溶着面に吸収されるレーザ光のエネルギが小さくなる。このため、斜め照射の場合は、ボディの溶着面においてレーザ照射により受ける熱的影響が垂直照射の場合と比較して小さくなる。したがって、斜め照射によれば、前述したようにレーザの照射条件を適宜設定することによりボディの溶着面における急激な温度上昇や入熱過大を回避しようとする場合に、たとえ照射条件の小さな調整ミス等が多少あったとしても、垂直照射の場合のようにボディの溶着面温度が大きく変化するようなことはなく、急激な温度上昇や入熱過大を回避することが容易となる。したがって、斜め照射によれば、単純な照射条件の調整によっても、ボディのストレスクラック発生を容易、かつ、効果的に抑制することが可能となる。
【００２２】
なお、ＰＣ材からなるレンズにおいては、前述のとおり、ＰＣの高透過性によりレーザ透過中の内部発熱がほとんどなく、レーザ吸収側のボディからの熱伝達のみで加熱溶融され、しかもボディとの界面のみが溶融して溶着することから、前記熱影響部がほとんどなく、ストレスクラックがほとんど発生しない。
【００２３】
したがって、請求項１に記載の車両用灯具のレーザ溶着方法によれば、レンズ及びボディの双方において、ストレスクラックの発生を効果的に抑えることができ、該ストレスクラック発生による強度低下の問題を効果的に抑制することが可能となる。
【００２４】
また、レンズがＰＣ材から構成されるとともに、ボディがＰＣ系材から構成されていることから、レンズ及びボディの双方に含まれるＰＣの存在により、両者の溶着強度を向上させる上で有利となる。
【００２５】
ところで、請求項１記載の車両用灯具のレーザ溶着方法では、照射工程で、ボディの溶着面に対してレーザ光を斜め照射することから、溶着面で反射するレーザ光が垂直照射の場合と比べて多くなる分だけ、レーザ溶着に使われないレーザ光のエネルギロスが大きくなり、コスト面及び生産性の面では不利となる。
【００２６】
そこで、請求項１記載の車両用灯具のレーザ溶着方法では、透過性樹脂よりなるレンズの当接端部を嵌合凸部により構成するとともに、吸収性樹脂よりなるボディの当接端部を該嵌合凸部と嵌合可能な嵌合凹部により構成し、前記当接工程では、該嵌合凸部と該嵌合凹部とを嵌合させ、前記照射工程では、該嵌合凹部の内面のうちの少なくとも一部に対してレーザ光を斜め照射するようにしている。
【００２７】
かかる態様によれば、嵌合凹部の内面のうちの少なくとも一部に斜め照射されたレーザ光を該面で反射させて嵌合凹部の内面の他の部分に到達させることができる。なお、反射光はレンズ側の嵌合凸部内を透過することになるが、ＰＣ材よりなるレンズの高透過性により、反射光の多くを他の部分に到達させることができる。このように、嵌合凹部の内面同士におけるレーザ光の反射の繰り返しを利用することにより、上記エネルギロスを低減させつつ、ボディの溶着面において分散した入熱状態として急激な温度上昇を効果的に抑えることができる。
【００３２】
さらに、請求項２記載の車両用灯具のレーザ溶着方法は、加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディと、該レーザ光に対して吸収性のある吸収性樹脂材からなるリフレクタとの当接端部同士を当接させる当接工程と、上記レンズ側からの上記レーザ光の照射により、上記レンズの当接端部、上記ボディの当接端部及び上記リフレクタの当接端部の各溶着面を加熱溶融させて溶着し、該レンズ、該ボディ及び該リフレクタを一体的に接合する照射工程とからなる。
【００３３】
上記レンズはＰＣ材からなり、上記ボディはＡＢＳ系材からなり、上記リフレクタはＰＥＴ系材又はＰＢＴ系材からなり、上記照射工程では、上記レンズ側から上記リフレクタの上記当接端部の溶着面に向けて上記レーザ光を照射するとともに、該溶着面で反射したレーザ光を上記ボディの上記当接端部の溶着面に到達させることにより、該レンズ及び該リフレクタ同士並びに該レンズ及び該ボディ同士を溶着することを特徴とする。
【００３４】
上記ボディを構成するＡＢＳ系材とは、ＡＢＳ単独からなるＡＢＳ材（必要に応じてレーザ光に対する所定の吸収性を付与すべく着色材が添加されたもの）、又はＡＢＳを含むアロイ材を意味する。アロイ材におけるＡＢＳの相手材としては、ＡＡＳ、ＰＢＴ、ＰＥＴ、ＰＭＭＡ、ＰＡ（ポリアミド）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）やエラストマー等を挙げることができる。なお、ＡＢＳ系材からなるボディには、レーザ光に対して所定の吸収性を有する吸収性樹脂材とすべく、必要に応じて、カーボンブラック、染料や顔料等の所定の着色材を混入することができ、また必要に応じて、ガラス繊維やカーボン繊維等の補強繊維を添加してもよい。
【００３５】
上記リフレクタを構成するＰＥＴ系材とは、ＰＥＴ単独からなるＰＥＴ材（必要に応じてレーザ光に対する所定の吸収性を付与すべく着色材が添加されたもの）又はＰＥＴを含むアロイ材を意味する。アロイ材におけるＰＥＴの相手材としては、ＡＡＳ、ＡＢＳ、ＰＢＴ、ＰＭＭＡ、ＰＡ（ポリアミド）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）やエラストマー等を挙げることができる。同様に、上記リフレクタを構成するＰＢＴ材とは、ＰＢＴ単独からなるＰＢＴ材（必要に応じてレーザ光に対する所定の吸収性を付与すべく着色材が添加されたもの）又はＰＢＴを含むアロイ材を意味する。アロイ材におけるＰＢＴの相手材としては、ＡＡＳ、ＡＢＳ、ＰＥＴ、ＰＭＭＡ、ＰＡ（ポリアミド）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）やエラストマー等を挙げることができる。なお、ＰＥＴ系材又はＰＢＴ系材からなるリフレクタには、レーザ光に対して所定の吸収性を有する吸収性樹脂材とすべく、必要に応じて、カーボンブラック、染料や顔料等の所定の着色材を混入することができ、また必要に応じて、ガラス繊維やカーボン繊維等の補強繊維を添加してもよい。
【００３６】
そして、上記照射工程で、レンズ側からリフレクタの当接端部の溶着面に向けてレーザ光を照射するとともに、該溶着面で反射したレーザ光をレンズの当接端部内を透過させてボディの当接端部の溶着面に到達させることにより、ボディにおけるストレスクラックの発生を抑制しつつ、該レンズ及び該リフレクタ同士並びに該レンズ及び該ボディ同士を溶着することが可能となる。
【００３７】
すなわち、レンズ側からリフレクタの溶着面に照射されたレーザ光は、その一部が該リフレクタの溶着面に吸収されるとともに、残りが該溶着面で反射してボディの溶着面に到達する。このため、リフレクタの溶着面が加熱溶融されるとともに、該溶着面と当接するレンズの溶着面がリフレクタの溶着面からの熱伝達により加熱溶融され、レンズ及びリフレクタの溶着面同士の溶着が可能となる。また、リフレクタの溶着面で反射したレーザ光がボディの溶着面に到達し、吸収されることにより、該ボディの溶着面が加熱溶融されるとともに、該溶着面と当接するレンズの溶着面がボディの溶着面からの熱伝達により加熱溶融され、レンズ及びボディの溶着面同士の溶着が可能となる。
【００３８】
一方、上記レンズを構成するＰＣ材と、上記ボディを構成するＡＢＳ系材とは、異種材ではあるが、互いに相溶性のある相溶系の材料であるため、レーザ溶着が可能となる。
【００３９】
また、上記ボディを構成するＡＢＳ系材に含まれるＡＢＳは、ストレスクラックの発生しにくい材料である反面、ＰＣと比較して、低融点（約１７０℃）で耐熱性の低い材料である。このため、ＡＢＳ系材よりなるボディはストレスクラック発生の問題を効果的に解消しうる反面、仮にレンズ側から直接ＡＢＳ系材よりなるボディにレーザ光を照射すると、熱劣化が発生し易くなるという問題がある。なお、レンズ側から直接ＡＢＳ系材よりなるボディにレーザ光を照射する場合であっても、レーザの照射条件を適宜調整すれば、ボディにおける熱劣化の発生自体は抑えることができる。しかし、この場合はボディの溶着面における入熱不足及び該溶着面からレンズの溶着面への熱伝達不足により、溶着界面におけるボディ及びレンズの溶融不足が起こり、十分な溶着強度を確保することが不可能又は困難となる。
【００４０】
この点、請求項２記載の発明では、上述のとおりレンズ側からのレーザ光をまずリフレクタに照射し、その反射光をレンズの当接端部内を透過させてボディに照射している。このため、ボディの溶接面に到達するレーザ光は、レンズ側から直接照射される場合と比較して、リフレクタの溶着面で吸収される分及び反射光がレンズの当接端部内を透過する間に該レンズ内で吸収される分だけ、エネルギが低いものとなる。したがって、耐熱性の低いＡＢＳ系材からなるボディであっても、ボディの溶着面における熱劣化を効果的に抑えることができる。
【００４１】
しかも、レンズの当接端部は、レンズ側からリフレクタの溶着面に向かって照射されたレーザ光が該溶着面に向かう際、及び該溶着面で反射した反射光がボディの溶着面に向かう際の少なくとも２回にわたってレーザ光が透過しており、反射光が透過する回数が多い分だけより大きく内部発熱している。すなわち、レンズの当接端部は、反射光の透過により予熱された状態となっている。このため、かかる予熱分だけ、ボディ及びレンズ間の十分な溶着強度を確保するめに必要なボディの溶着面からレンズの溶着面への熱伝達量、ひいてはボディの溶着面における入熱量を少なくすることができる。したがって、ボディの溶着面における入熱量が、ＡＢＳの熱劣化を防止しうる程度に低減された場合であっても、ボディ及びレンズ間における溶着強度を十分に確保することが可能となる。
【００４２】
よって、請求項２記載の発明によれば、レンズ及びボディ間における溶着強度を十分に確保しつつ、ボディの熱劣化の発生を抑えることができ、しかもレンズ及びボディの双方におけるストレスクラックの発生を効果的に抑えて、該ストレスクラック発生による強度低下の問題を効果的に抑制することが可能となる。
【００４３】
なお、レンズ側からレーザ光が直接照射されるリフレクタはＰＥＴ系材又はＰＢＴ系材からなり、前述のとおりＰＥＴ系材又はＰＢＴ系材はストレスクラックが発生しにくい材料であることから、リフレクタにおいてはレーザ光が直接照射されてもストレスクラックの問題は発生しない。
【００４４】
また、上記ボディに採用されるＡＢＳは、ＰＣ、ＰＥＴやＰＢＴ等と比べて低価格であるため、コスト面でも有利となる。
【００４５】
さらに、上記照射工程では、リフレクタの溶着面でのレーザ光の反射を利用して、レンズ及びリフレクタ同士並びにレンズ及びボディ同士を同時にレーザ溶着することができる。すなわち、一度のレーザ溶着により、レンズ、ボディ及びリフレクタの三者を一体的に接合することができるので、車両用灯具の生産性を向上させる上で有利となる。
【００４６】
なお、加熱源として用いるレーザ光の種類としては、レーザ光を透過させる透過性樹脂材の吸収スペクトルや板厚（透過長）等との関係で、透過性樹脂材内での透過率が所定値以上となるような波長を有するものが適宜選定される。例えば、ＹＡＧ：Ｎｄ３＋レーザ（レーザ光の波長：１０６０ｎｍ）や半導体レーザ（レーザ光の波長：５００〜１０００ｎｍ）を用いることができる。
【００４７】
また、レーザの出力、照射密度や加工速度（移動速度）等の照射条件は、樹脂の種類等に応じて適宜設定可能である。
【００４８】
【実施例】
以下、本発明の具体的な実施例を図面に基づいて説明する。
【００４９】
（実施例１）
図１〜図３に示す本実施例は、請求項１記載の車両用灯具のレーザ溶着方法を具現化したもので、車両用灯具としての自動車用ヘッドライトの製造に請求項１記載の発明を適用したものである。
【００５０】
図１は、自動車用ヘッドライトを切断した斜視図であり、図２は接合構造を示す要部断面図である。
【００５１】
このヘッドライトは、図１に示すように、レンズ１と、ランプボディ２と、リフレクタ（反射鏡）３と、ランプ４と、カバー５とから構成された中空体である。
【００５２】
レンズ１は、加熱源としてのレーザ光に対して透過性のある透過樹脂材からなり、具体的にはＰＣ材よりなる。
【００５３】
ランプボディ２は、加熱源としてのレーザ光に対して吸収性のある吸収性樹脂材からなり、具体的にはガラス繊維が３０ｗｔ％、着色剤としてのカーボンブラックが適宜量添加されたＰＣ系材（ＰＣとＰＥＴとのアロイ材）よりなる。
【００５４】
そして、レンズ１の当接端部１０と、ボディ２の当接端部２０とが当接された状態で、レーザ溶着により一体的に接合されている。
【００５５】
また、ボディ２の内部には、エポキシ（ＢＭＣ）よりなるリフレクタ３が接着剤等により配設、固定されており、ボディ２及びリフレクタ３の後方壁にそれぞれ貫設された貫孔２ａ及び３ａにはランプ４が配設されるとともに、ボディ２の貫孔２ａがカバー５で塞がれている。
【００５６】
図２に示すように、レンズ１の当接端部１０には、基端側（図２の左端側）に段部を残しつつ中空体の内側（図２の下側、以下同様）及び中空体の外側（図２の上側、以下同様）がテーパ状に切り欠かれるととものその先端部が切り落とされ、先端側へ漸次縮小して突出する形状に形成された嵌合凸部１１が設けられている。この嵌合凸部１１は、先端面１１ａと、中空体の内側及び外側の各テーパ外面１１ｂ及び１１ｃと、各テーパ外面１１ｂ及び１１ｃの基端に交差する内側及び外側の段状面１１ｄ及び１１ｅとを有している。
【００５７】
一方、ボディ２の当接端部２０には、先端側（図２の左端側）へ漸次拡開して突出する形状に形成され、上記嵌合凸部１１と嵌合可能な嵌合凹部２１が設けられている。この嵌合凹部２１は、上記先端面１１ａと互いに整合する底面２１ａと、各上記テーパ外面１１ｂ及び１１ｃとそれぞれ互いに整合する中空体の内側及び外側の各テーパ内面２１ｂ及び２１ｃと、各テーパ内面２１ｂ及び２１ｃの先端に交差し、各上記段状面１１ｄ及び１１ｅとそれぞれ互いに整合する中空体の内側及び外側の先端面２１ｄ及び２１ｅとを有している。なお、底面２１ａ並びに内側及び外側のテーパ内面２１ｂ及び２１ｃにより、嵌合凹部２１の内面が構成される。
【００５８】
そして、レンズ１の嵌合凸部１１及びボディ２の嵌合凹部２１同士が嵌合されるとともに、先端面１１ａ及び底面２１ａ同士と、内側のテーパ外面１１ｂ及びテーパ内面２１ｂ同士と、外側のテーパ外面１１ｃ及びテーパ内面２１ｃ同士と、内側の段状面１１ｄ及び先端面２１ｄ同士と、外側の段状面１１ｅ及び先端面２１ｅ同士が、それぞれレーザ溶着により一体的に接合されている。
【００５９】
なお、本実施例では、上記嵌合凸部１１の先端面１１ａ、各テーパ外面１１ｂ、１１ｃ及び各段状面１１ｄ、１１ｅ、並びに上記嵌合凹部２１の底面２１ａ、各テーパ内面２１ｂ、２１ｃ及び各先端面２１ｄ、２１ｅがレーザ溶着により溶着される溶着面となる。
【００６０】
上記構成を有する本実施例の樹脂成形品は、以下のようにして製造した。
【００６１】
（当接工程）
まず、レンズ１及びボディ２を射出成形によりそれぞれ所定形状に形成した後、ボディ２の内面にリフレクターを配設、固定した。そして、レンズ１の当接端部１０とボディ２の当接端部２０とを当接させるとともに、レンズ１の嵌合凸部１１とボディ２の嵌合凹部２１とを嵌合した。
【００６２】
（照射工程）
この状態で、ボディ２の嵌合凹部２１の底面２１ａの一部（中空体の内側で図２の下側部分）、内側のテーパ内面２１ｂの全体並びに内側及び外側の先端面２１ｄ及び２１ｅの各面に対してそれぞれレーザ光が斜め方向から入射するように、透過性樹脂材としてのレンズ１側で中空体の外側から上記各面に向けてレーザ光６を斜め照射した（図２参照）。この斜め照射する際のレーザ光の入射角（θ）は、嵌合凹部２１の底面２１ａ及び各先端面２１ｄ、２１ｅに対しては３０度とし、嵌合凹部２１の内側のテーパ内面２１ｂに対しては４５度とした（図３参照）。なお、嵌合凹部２１の底面２１ａの一部（中空体の外側で図２の上側部分）及び外側のテーパ内面２１ｃには、レーザ光を直接照射せずに、嵌合凹部２１の底面２１ａの他の部分や内側のテーパ内面２１ｂ等で反射した反射光を照射した。また、レーザ光としてはＹＡＧ−ネオジウムレーザ光（波長１０６０ｎｍ）を用いた。照射条件は、出力：２００〜４００Ｗ、加工速度：５ｍ／ｍｉｎとした。
【００６３】
上記レーザ照射により、嵌合凹部２１の内面における反射の繰り返しを利用しつつ、嵌合凹部２１の内面全体、すなわち底面２１ａ及び各テーパ内面２１ｂ、２１ｃの全体にレーザ光を照射して、レンズ１の嵌合凸部１１の各溶着面及びボディ２の嵌合凹部２１の各溶着面同士を加熱溶融して溶着し、一体的に接合した。
【００６４】
こうして得られた接合部では、各溶着面同士が溶融されて接合されており、該溶着面同士の間では両部材を構成する両樹脂が溶融して互いに入り込み絡まった状態が形成されているため、強固な接合状態を構成して高い接合強度及び耐圧強度を有している。
【００６５】
また、本実施例では、嵌合凸部１１の各溶着面及び嵌合凹部２１の各溶着面同士のレーザ溶着による接合に加えて、レンズ１の嵌合凸部１１とボディ２の嵌合凹部２１との嵌合、及びレンズ１の各段状面１１ｄ、１１ｅとボディ２の各先端面２１ｄ、２１ｅとの係合により構造的にも強固な接合部となっているので、より高い接合強度及び耐圧強度を有している。
【００６６】
さらに、本実施例では、レンズ１がＰＣ材からなり、ボディ２がＰＣ系材、すなわちＰＣを含むアロイ材からなる。このため、レンズ１及びボディ２の双方に含まれるＰＣの存在により、両者の溶着強度を向上させる上で有利となる。
【００６７】
そして、ＰＣ材からなるレンズ１においては、ＰＣの高透過性によりレーザ透過中の内部発熱がほとんどなく、レーザ吸収側のボディ２からの熱伝達のみで加熱溶融され、しかもボディとの界面のみが溶融して溶着することから、熱影響部がほとんどなく、ストレスクラックがほとんど発生しない。
【００６８】
一方、ＰＣ系材からなるボディ２に対して、従来行われている一般的な垂直照射によるレーザ溶着をすれば、ストレスクラックの発生が問題となる。
【００６９】
この点、本実施例では、上記照射工程で、ボディ２の各溶着面（嵌合凹部２１の底面２１ａ、内側のテーパ内面２１ｂ並びに内側及び外側の先端面２１ｄ及び２１ｅの各面）に対してレーザ光を斜め照射している。このため、垂直照射する場合と比較して、各該溶着面で反射するレーザ光が多くなる分だけ、各該溶着面に吸収されるレーザ光のエネルギが小さくなり、各該溶着面においてレーザ照射により受ける熱的影響が小さくなる。したがって、レーザの照射条件を適宜設定することによりボディの各溶着面における急激な温度上昇や入熱過大を回避しようとする場合に、たとえ照射条件の小さな調整ミス等が多少あったとしても、垂直照射の場合のようにボディ２の溶着面温度が大きく変化するようなことはなく、急激な温度上昇や入熱過大を回避することが容易となる。よって、単純な照射条件の調整によっても、ボディ２のストレスクラック発生を容易、かつ、効果的に抑制することが可能となる。
【００７０】
また、本実施例では、透過性樹脂よりなるレンズ１の当接端部１０を嵌合凸部１１により構成するとともに、吸収性樹脂よりなるボディ２の当接端部２０を嵌合凸部１１と嵌合可能な嵌合凹部２１により構成し、嵌合凹部２１の内面のうちの一部に対してレーザ光を斜め照射し、該嵌合凹部２１の内面における反射の繰り返しを利用して、該内面全体にレーザ光を照射している。このため、エネルギロスを低減させつつ、ボディ２の溶着面において分散した入熱状態として急激な温度上昇を効果的に抑えることができる。
【００７１】
なお、この実施例では、ボディ２を構成するＰＣ系材として、ＰＣとＰＥＴとのアロイ材を採用したが、この他に、ＰＣ単独からなるＰＣ材（レーザ光に対する所定の吸収性を付与すべく着色材が添加されたもの）や、ＡＡＳ、ＡＢＳ、ＰＢＴ、ＰＭＭＡ、ＰＡ、ＰＥ、ＰＰ又はエラストマーとＰＣとのアロイ材を採用しても、同様の作用効果を達成することができる。
【００７２】
（参考例）
本参考例は、ボディ２の樹脂材料を変更したこと以外は、前記実施例１と同様の構成を有する。
【００７３】
すなわち、本参考例に係るヘッドライトは、吸収性樹脂としてのボディ２がＰＥＴ材からなる。
【００７４】
ボディ２を構成するＰＥＴ材は、ストレスクラックの発生しにくい材料である。このため、かかる材料をボディ２に採用することにより、ＰＣ材よりなるレンズ１に対してボディ２をレーザ溶着しても、ボディ２にストレスクラックがほとんど発生しない。したがって、ボディ２におけるストレスクラックの発生をより効果的に抑えることができる。
【００７５】
その他の作用効果は前記実施例１と同様である。
【００７６】
なお、この参考例では、ボディ２の樹脂材料としてＰＥＴ材を採用したが、これの代わりに、ＰＥＴとＡＢＳとのアロイ材、又はＰＢＴ材若しくはＰＢＴとＡＢＳとのアロイ材を採用しても、ＰＥＴ材を採用した場合と同様の作用効果を達成することができる。
【００７７】
また、ボディ２の樹脂材料として、ＰＥＴ材若しくはＰＥＴとＡＢＳとのアロイ材、又はＰＢＴ材若しくはＰＢＴとＡＢＳとのアロイ材を採用した場合は、こら等の材料特性によりストレスクラックの発生を抑制することができることから、レーザ光を斜め照射しない場合であっても、ボディ２におけるストレスクラックの発生を効果的に抑制することが可能となる。
【００７８】
（実施例２）
図４及び図５に示す本実施例は、請求項２記載の車両用灯具のレーザ溶着方法を具現化したものである。
【００７９】
すなわち、本実施例では、レンズ１が加熱源としてのレーザ光に対して透過性のある透過性樹脂からなり、具体的にはＰＣ材よりなる。
【００８０】
ボディ２は、加熱源としてのレーザ光に対して吸収性のある透過樹脂材からなり、具体的にはガラス繊維が３０ｗｔ％、着色剤としてのカーボンブラックが適宜量添加されたＡＢＳ材よりなる。
【００８１】
また、リフレクタ３が、加熱源としてのレーザ光に対して吸収性のある吸収性樹脂材からなり、具体的にはガラス繊維が３０ｗｔ％、着色剤としてのカーボンブラックが適宜量添加されたＰＥＴ材よりなる。
【００８２】
そして、レンズ１の当接端部１０と、ボディ２の当接端部２０と、リフレクタ３の当接端部３０が当接された状態で、こらら三者の当接端部１０、２０及び３０がレーザ溶着により一体的に接合されている。
【００８３】
具体的には、図５に示すように、レンズ１の当接端部１０は、前記実施例１と同様の嵌合凸部１１が形成されている。
【００８４】
一方、ボディ２の当接端部２０は、前記実施例１で示した嵌合凹部２１の内側（図５の下側）の壁部を切り欠いた形状をなしている。すなわち、このボディ２の嵌合凹部２１は、先端側（図５の左端側）へ漸次拡開して突出する形状に形成されるとともに、一方側（中空体の内側、図５の下側）の壁部が切り欠かれた形状をなし、嵌合凸部１１の先端面１１ａ及びリフレクタ３の当接端部３０の第２側端面（図５の右側の端面）３０ｃが整合して当接する段状底面２１ｆと、嵌合凸部１１の外側（図５の上側）のテーパ外面１１ｃと互いに整合して当接する外側のテーパ内面２１ｃと、該テーパ内面２１ｃの先端に交差し、嵌合凸部１１の外側の段状面１１ｅと互いに整合して当接する外側の先端面２１ｅとを有している。
【００８５】
また、リフレクタ３の当接端部３０は、嵌合凸部１１の内側のテーパ外面１１ｂと互いに整合して当接する傾斜先端面３０ａと、嵌合凸部１１の内側の段状面１１ｄと互いに整合して当接する第１側端面（図５の左側の端面）３０ｂと、上記第２側端面３０ｃとを有している。
【００８６】
そして、レンズ１の嵌合凸部１１及びボディ２の嵌合凹部２１同士が嵌合されるとともに、嵌合された嵌合凸部１１及び嵌合凹部２１間に形成される凹部内にリフレクタ３の当接端部３０の嵌合先端部が嵌合され、嵌合凸部１１の内側の段状面１１ｄ及びリフレクタ３の第１側端面３０ｂ同士と、嵌合凸部１１の内側のテーパ外面１１ｂ及びリフレクタ３の傾斜先端面３０ａ同士と、嵌合凸部１１の先端面１１ａ及び嵌合凹部２１の段状底面２１ｆ同士と、嵌合凸部１１の外側のテーパ外面１１ｃ及び嵌合凹部２１の外側のテーパ内面２１ｃ同士とが、それぞれレーザ溶着により一体的に接合されている。
【００８７】
なお、本実施例では、上記嵌合凸部１１の先端面１１ａ、各テーパ外面１１ｂ、１１ｃ及び内側の段状面１１ｄ、並びに上記嵌合凹部２１の段状底面２１ｅの一部（段状底面２１ｅのうち嵌合凸部１１の先端面１１ａが当接する部分）及び外側のテーパ内面２１ｃ、並びにリフレクタ３の第１側端面３０ｂ及び傾斜先端面３０ａがレーザ溶着により溶着される溶着面となる。
【００８８】
上記構成を有する本実施例の樹脂成形品は、以下のようにして製造した。
【００８９】
（当接工程）
まず、レンズ１、ボディ２及びリフレクタ３を射出成形によりそれぞれ所定形状に形成した後、ボディ２の内側にリフレクターを配設しつつ、レンズ１の当接端部１０、ボディ２の当接端部２０及びリフレクタ３の当接端部３０を当接させるとともに、レンズ１の嵌合凸部１１とボディ２の嵌合凹部２１とを嵌合し、さらに嵌合凸部１１及び嵌合凹部２１間にリフレクタ３の当接端部３０の嵌合先端部を嵌合した。
【００９０】
（照射工程）
この状態で、リフレクタ３の傾斜先端面３０ａ及び第１側端面３０ｂの各面に対してそれぞれレーザ光が斜め方向から入射するように、透過性樹脂材としてのレンズ１側で中空体の外側から上記各面に向けてレーザ光６を斜め照射した（図５参照）。なお、嵌合凹部２１の段状底面２１ｆ、外側のテーパ内面２１ｃ及び外側の先端面２１ｅにはレーザ光を照射しなかった。そして、嵌合凹部２１の段状底面２１ｆ及び外側のテーパ内面２１ｃには、リフレクタ３の傾斜先端面３０ａ等で反射した反射光を照射した。また、レーザ光としてはＹＡＧ−ネオジウムレーザ光（波長１０６０ｎｍ）を用いた。照射条件は、出力：２００〜４００Ｗ、加工速度：５ｍ／ｍｉｎとした。
【００９１】
上記レーザ照射により、嵌合凹部２１の段状底面２１ｆ及び外側のテーパ内面２１ｃ、並びにリフレクタ３の傾斜先端面３０ａにおける反射の繰り返しを利用しつつ、溶着面の全体にレーザ光を照射して、各溶着面同士を加熱溶融して溶着し、一体的に接合した。
【００９２】
こうして得られた接合部では、各溶着面同士が溶融されて接合されており、該溶着面同士の間では両部材を構成する両樹脂が溶融して互いに入り込み絡まった状態が形成されているため、強固な接合状態を構成して高い接合強度及び耐圧強度を有している。
【００９３】
また、本実施例では、嵌合凸部１１の各溶着面及び嵌合凹部２１の各溶着面同士並びに嵌合凸部１１の各溶着面及びリフレクタ３の核溶着面同士のレーザ溶着による接合に加えて、レンズ１の嵌合凸部１１とボディ２の嵌合凹部２１との嵌合、及び嵌合凸部と嵌合凹部２１との間に形成された凹部とリフレクタ３の嵌合先端部との嵌合により構造的にも強固な接合部となっているので、より高い接合強度及び耐圧強度を有している。
【００９４】
そして、ＰＣ材からなるレンズ１においては、ＰＣの高透過性によりレーザ透過中の内部発熱がほとんどなく、レーザ吸収側のリフレクタ３及びボディ２からの熱伝達のみで加熱溶融され、しかもリフレクタ３及びボディとの界面のみが溶融して溶着することから、熱影響部がほとんどなく、ストレスクラックがほとんど発生しない。
【００９５】
一方、ＡＢＳ材からなるボディ２及びＰＥＴ材からなるリフレクタ３においては、これらの材料特性により、ストレスクラックがほとんど発生しない。
【００９６】
ただし、ボディ２を構成するＡＢＳは、ＰＣ、ＰＥＴやＰＢＴ等と比べて、低価格であるためコスト面では有利となるが、耐熱性の低い材料である。このため、ＡＢＳ材よりなるボディ２に直接レーザ光を照射すると熱劣化の問題が発生する。
【００９７】
この点、本実施例では、上記照射工程で、ボディ２の溶着面にはレーザ光を直接照射していない。すなわち、レンズ１側からリフレクタ３の傾斜先端面３０ａ及び第１側端面３０ｂにレーザ光を照射し、この傾斜先端面３０ａで反射した反射光を、レンズ１の嵌合凸部１１内を透過させてボディ２の段状底面２１ｆ及び外側のテーパ内面２１ｃに到達させて照射している。このため、ボディ２の段状底面２１ｆ及び外側のテーパ内面２１ｃに到達するレーザ光は、レンズ１側から直接照射される場合と比較して、リフレクタ３の傾斜先端面３０ａで吸収される分及び反射光がレンズ１の嵌合凸部１１内を透過する間に該嵌合凸部１１内で吸収される分だけ、エネルギが低いものとなる。したがって、耐熱性の低いＡＢＳ系材からなるボディ２であっても、ボディ２の溶着面における熱劣化を効果的に抑えることができる。
【００９８】
しかも、レンズ１の嵌合凸部１１は、レンズ１側からリフレクタ３の傾斜先端面３０ａに向かって照射されたレーザ光が傾斜先端面３０ａに向かう際、及び該傾斜先端面３０ａで反射した反射光がボディ２の溶着面に向かう際の少なくとも２回にわたってレーザ光が透過しており、反射光が透過する回数が多い分だけより大きく内部発熱している。すなわち、レンズ１の嵌合凸部１１は、反射光の透過により予熱された状態となっている。このため、かかる予熱分だけ、レンズ１及びボディ２の十分な溶着強度を確保するめに必要なボディ２の溶着面からレンズ１の溶着面への熱伝達量、ひいてはボディ２の溶着面における入熱量を少なくすることができる。したがって、ボディ２の溶着面における入熱量が、ＡＢＳの熱劣化を防止しうる程度に低減された場合であっても、ボディ１及びレンズ２間における溶着強度を十分に確保することが可能となる。
【００９９】
よって、本実施例によれば、レンズ１及びボディ２間における溶着強度を十分に確保しつつ、ボディ２の熱劣化の発生を抑えることができ、しかもレンズ１及びボディ２の双方におけるストレスクラックの発生を効果的に抑えて、該ストレスクラック発生による強度低下の問題を効果的に抑制することが可能となる。
【０１００】
また、本実施例では、一度のレーザ溶着により、レンズ１、ボディ２及びリフレクタ３の三者を一体的に接合することができるので、車両用灯具の生産性を向上させる上で有利となる。
【０１０１】
なお、この実施例では、ボディ２の樹脂材料としてＡＢＳ材を採用したが、これの代わりに、ＡＡＳ、ＰＢＴ、ＰＥＴ、ＰＭＭＡ、ＰＡ、ＰＥ、ＰＰ又はエラストマーとＡＢＳとのアロイ材を採用しても、ＡＢＳ材を採用した場合と同様の作用効果を達成することができる。
【０１０２】
また、この実施例では、リフレクタ３の樹脂材料としてＰＥＴ材を採用したが、これの代わりに、ＡＡＳ、ＡＢＳ、ＰＢＴ、ＰＭＭＡ、ＰＡ、ＰＥ、ＰＰ若しくはエラストマーとＰＥＴとのアロイ材や、ＰＢＴ単独からなるＰＢＴ材又はＡＡＳ、ＡＢＳ、ＰＥＴ、ＰＭＭＡ、ＰＡ、ＰＥ、ＰＰ若しくはエラストマーとＰＢＴとのアロイ材を採用しても、ＰＥＴ材を採用した場合と同様の作用効果を達成することができる。
【図面の簡単な説明】
【図１】 本発明の実施例１に係る自動車用ヘッドライトを切断した斜視図である。
【図２】 本発明の実施例１に係る自動車用ヘッドライトの接合構造を示す要部断面図である。
【図３】 溶着面に対するレーザ光の入射角を説明する断面図である。
【図４】 本発明の実施例２に係る自動車用ヘッドライトを切断した斜視図である。
【図５】 本発明の実施例２に係る自動車用ヘッドライトの接合構造を示す要部断面図である。
【符号の説明】
１…レンズ ２…ランプボディ（ボディ）
３…リフレクタ １０，２０，３０…当接端部
１１…嵌合凸部 ２１…嵌合凹部[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a method for laser welding a vehicle lamp.To the lawSpecifically, laser welding of a vehicle lamp that integrally joins a lens and a body using laser weldingTo the lawRelated.
[0002]
[Prior art]
In general, a vehicular lamp such as a headlight of an automobile has a structure in which a lens and a body holding a lamp and a reflector (reflecting mirror) are integrally joined. As a method for joining the lens and the body, Japanese Patent Application Laid-Open No. 2000-294012 discloses a method using laser welding.
[0003]
In joining of a lens and a body by laser welding, a lens made of a transparent resin material that is transmissive to laser light as a heating source, and a body made of an absorbent resin material that is absorbent to the laser light Are abutted with each other, and laser light is irradiated from the lens side toward the abutting end of the body. As a result, the laser light transmitted through the lens reaches the contact end portion of the body and is absorbed, and the laser light absorbed at the contact end portion is accumulated as energy. As a result, the contact end portion of the body is heated and melted, and the contact end portion of the lens is heated and melted by heat transfer from the contact end portion of the body. In this state, if the contact end portions of the lens and the body are pressure-bonded to each other, they can be joined together.
[0004]
In the vehicular lamp disclosed in the above Japanese Patent Laid-Open No. 2000-294012, the material of the lens is PC (polycarbonate), PMMA (polymethyl methacrylate), etc. from the viewpoint of transparency, heat resistance, strength, and the like. As the material of the body, from the viewpoint of heat resistance, strength, etc., a polymer alloy containing PC, specifically, PC and AAS (acrylic / acrylonitrile / styrene polymer), PC and ABS (alichloronitrile) are used. A polymer alloy such as butadiene / styrene polymer), PC and PET (polyethylene terephthalate) or PC and PBT (polybutylene terephthalate) is used.
[0005]
[Problems to be solved by the invention]
By the way, the PC itself used for the lens and the body generally has a laser light transmittance of about 80 to 95%, and is excellent in impact strength, heat resistance, dimensional stability, and the like. However, this PC has a characteristic that cracks (stress cracks) easily occur when a certain stress level is exceeded. This stress crack is particularly likely to occur in a heat-affected zone (a portion that has not been melted but has changed in structure or mechanical properties) or a portion that has been thermally deteriorated.
[0006]
For this reason, when laser welding a body made of a polymer alloy containing PC to a lens made of PC, stress cracks are likely to occur on the body side as shown below, and the occurrence of stress cracks can be suppressed. Since it is difficult, there is a problem that the reliability of the strength of the body is lowered.
[0007]
In other words, the lens on the laser transmission side has almost no internal heat generation due to laser absorption during laser transmission due to the high transmittance of the PC during laser welding, and is heated and melted only by heat transfer from the body on the laser absorption side. Only the interface melts and welds. For this reason, in the lens on the laser transmission side, there is almost no heat-affected zone (of course, no thermal degradation), and stress cracks hardly occur.
[0008]
On the other hand, the body on the laser absorption side is directly heated and melted by the absorption of laser light, and the thermal effect due to laser irradiation is large and sensitive due to the high transparency of the lens made of PC. An increase in temperature and excessive heat input are likely to occur, making it difficult to suppress the formation of the heat affected zone and the occurrence of thermal degradation. For this reason, if the body contains PC, stress cracks are likely to occur.
[0009]
Here, abrupt temperature rise and excessive heat input on the welding surface of the body are avoided to some extent by appropriately setting laser irradiation conditions, for example, laser output, irradiation density, processing speed (moving speed), and the like. be able to. However, as described above, the welding surface of the body is greatly affected and sensitive to the thermal effects of laser irradiation, and thus is subject to various effects such as small adjustment errors and operation errors in the irradiation conditions. And the welding surface temperature of the body changes greatly. For this reason, depending on simple adjustment of irradiation conditions, it is difficult to reliably avoid sudden temperature rise and excessive heat input on the body welding surface, and therefore it is difficult to effectively suppress the occurrence of stress cracks in the body. Become.
[0010]
  The present invention has been made in view of the above circumstances, and a laser welding method for a vehicle lamp that can suppress the occurrence of stress cracks in the body when the body is laser welded to a PC lens.The lawThis is a technical problem to be solved.
[0011]
[Means for Solving the Problems]
  The laser welding method for a vehicular lamp according to claim 1, which solves the above-described problem, includes a lens made of a transparent resin material that is transmissive to laser light as a heating source, and a laser absorptive to the laser light. An abutting step for abutting the abutting ends with a body made of a certain absorbent resin material;
  By irradiating the laser light from the lens side, the welding surfaces of the contact end portion of the lens and the contact end portion of the body are heated and melted to weld the lens and the body together. A laser welding method for a vehicle lamp comprising an irradiation process to be joined,
  The lens is made of PC material and the body is made of PC material.And the contact end portion of the lens is constituted by a fitting convex portion, and the contact end portion of the body is constituted by a fitting concave portion that can be fitted to the fitting convex portion,
In the contact step, the fitting convex part and the fitting concave part are fitted,In the irradiation step, the welding surface of the contact end of the bodyAt least part of the inner surface of the fitting recessIn contrast, the laser beam is obliquely irradiated.
[0012]
Here, obliquely irradiating laser light means that the incident angle of the laser light is more than 0 degree and less than 90 degrees.
[0015]
  Claims for solving the above problems2The laser welding method for a vehicle lamp described above includes: a lens made of a transmissive resin material that is transmissive to laser light as a heating source; and a body made of an absorbent resin material that is absorbent to the laser light. And an abutting step for abutting the abutting ends with a reflector made of an absorbing resin material that absorbs the laser beam; and
  By irradiating the laser light from the lens side, the welding surfaces of the contact end portion of the lens, the contact end portion of the body, and the contact end portion of the reflector are heated and melted, and the lens, A laser welding method for a vehicular lamp comprising an irradiation step of integrally joining the body and the reflector,
  The lens is made of PC material, the body is made of ABS material, the reflector is made of PET material or PBT material,
  In the irradiation step, the laser light is irradiated from the lens side toward the welding surface of the contact end portion of the reflector, and the laser light reflected by the welding surface is transmitted through the contact end portion of the lens. The lens and the reflectors and the lens and the bodies are welded together by reaching the welding surface of the contact end portion of the body..
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  Claim1The laser welding method for a vehicle lamp described above includes: a lens made of a transmissive resin material that is transmissive to laser light as a heating source; and a body made of an absorbent resin material that is absorbent to the laser light. The abutting step of abutting the abutting end portions with each other, and laser welding from the lens side, the welding surfaces of the abutting end portion of the lens and the abutting end portion of the body are heated and melted. And an irradiation step of integrally welding the lens and the body. In this irradiation step, the laser light irradiated from the lens side passes through the lens, reaches the welding surface of the contact end portion of the body, and is absorbed. As a result of the laser light absorbed on the welded surface of the body being accumulated as energy, the welded surface of the body is heated and melted, and the welded surface of the contact end portion of the lens is transferred by heat transfer from the welded surface of the body. It is heated and melted. In this state, if the welding surfaces of the lens and the body are pressure-bonded, the two can be integrally joined.
[0017]
In the joint portion thus obtained, the weld surfaces are melted and joined, and between the weld surfaces, both resins constituting both members are melted and are intertwined with each other, so that the entangled state is formed. It has a strong bonding state and high bonding strength and pressure resistance.
[0018]
  Here, in the laser welding method for a vehicular lamp according to claim 1, the lens is made of a PC material and the body is made of a PC-based material.In addition, the contact end portion of the lens is constituted by a fitting convex portion, and the contact end portion of the body is constituted by a fitting concave portion that can be fitted to the fitting convex portion. , Fitting the fitting convex part and the fitting concave part,In the irradiation step, the welding surface of the contact end of the bodyAt least part of the inner surface of the fitting recessThe laser beam is obliquely irradiated to the above.
[0019]
The PC material constituting the body means a PC material made of PC alone (a colorant added to give a predetermined absorbability to laser light) or an alloy material containing PC. Examples of the counterpart material of PC in the alloy material include AAS, ABS, PBT, PET, PMMA, PA (polyamide), PE (polyethylene), PP (polypropylene), and elastomer. In addition, a predetermined colorant such as carbon black, a dye, or a pigment is mixed in the body made of the PC-based material, if necessary, so as to be an absorptive resin material having a predetermined absorbability with respect to the laser beam. In addition, if necessary, reinforcing fibers such as glass fibers and carbon fibers may be added.
[0020]
In the irradiation process, the generation of stress cracks in the body can be easily and effectively suppressed by obliquely irradiating the laser beam.
[0021]
That is, when the laser beam is obliquely irradiated to the welding surface of the body (hereinafter simply referred to as “diagonal irradiation”), the laser beam is irradiated from the vertical direction (hereinafter simply referred to as “vertical irradiation”). In comparison with, the amount of laser light absorbed by the welding surface is reduced by the amount of laser light reflected by the welding surface. For this reason, in the case of oblique irradiation, the thermal influence received by laser irradiation on the welding surface of the body is smaller than that in the case of vertical irradiation. Therefore, with oblique irradiation, a small misadjustment of irradiation conditions is necessary when trying to avoid a sudden rise in temperature or excessive heat input on the welding surface of the body by appropriately setting the laser irradiation conditions as described above. Even if there is some, etc., the welding surface temperature of the body does not change greatly as in the case of vertical irradiation, and it becomes easy to avoid a sudden temperature rise and excessive heat input. Therefore, according to the oblique irradiation, the occurrence of stress cracks in the body can be easily and effectively suppressed by simply adjusting the irradiation conditions.
[0022]
In the lens made of PC material, as described above, due to the high transmittance of PC, there is almost no internal heat generation during laser transmission, and it is heated and melted only by heat transfer from the body on the laser absorption side, and the interface with the body. Since only melts and welds, there is almost no said heat affected zone and stress cracks hardly occur.
[0023]
Therefore, according to the laser welding method for a vehicular lamp according to claim 1, it is possible to effectively suppress the occurrence of stress cracks in both the lens and the body, and the problem of strength reduction due to the occurrence of the stress cracks is effective. Can be suppressed.
[0024]
In addition, since the lens is made of a PC material and the body is made of a PC-based material, the presence of PC contained in both the lens and the body is advantageous in improving the welding strength of both. .
[0025]
By the way, in the laser welding method of the vehicular lamp according to claim 1, since the laser beam is obliquely irradiated to the welding surface of the body in the irradiation step, the laser beam reflected by the welding surface is compared with the case of vertical irradiation. Therefore, the energy loss of the laser beam that is not used for laser welding increases, which is disadvantageous in terms of cost and productivity.
[0026]
  Therefore,In the laser welding method of the vehicular lamp according to claim 1,The contact end portion of the lens made of a transparent resin is constituted by a fitting convex portion, and the contact end portion of the body made of an absorbent resin is constituted by a fitting concave portion that can be fitted to the fitting convex portion, In the contact step, the fitting convex portion and the fitting concave portion are fitted, and in the irradiation step, at least a part of the inner surface of the fitting concave portion is irradiated obliquely with laser light.Like.
[0027]
According to this aspect, the laser beam obliquely irradiated onto at least a part of the inner surface of the fitting recess can be reflected by the surface to reach the other part of the inner surface of the fitting recess. In addition, although reflected light permeate | transmits the inside of the fitting convex part by the side of a lens, most reflected light can be made to reach other parts with the high transmittance | permeability of the lens which consists of PC materials. As described above, by utilizing the repetition of the reflection of the laser light between the inner surfaces of the fitting recesses, it is possible to effectively increase the temperature suddenly as a heat input dispersed on the welding surface of the body while reducing the energy loss. Can be suppressed.
[0032]
  And claims2The laser welding method for a vehicle lamp described above includes: a lens made of a transmissive resin material that is transmissive to laser light as a heating source; and a body made of an absorbent resin material that is absorbent to the laser light. An abutting step of abutting the abutting ends of the absorptive resin material that absorbs the laser light with each other, and irradiation of the laser light from the lens side. A contact end portion, a contact end portion of the body, and a contact end portion of the reflector are heated and melted to weld, and the lens, the body, and the reflector are integrally joined. Become.
[0033]
The lens is made of a PC material, the body is made of an ABS-based material, the reflector is made of a PET-based material or a PBT-based material, and in the irradiation step, a welding surface of the contact end portion of the reflector from the lens side. And irradiating the laser beam toward the welding surface and causing the laser beam reflected by the welding surface to reach the welding surface of the contact end portion of the body, so that the lenses and the reflectors and the lenses and the bodies are It is characterized by welding.
[0034]
The ABS material constituting the body means an ABS material made of ABS alone (added with a coloring material to give a predetermined absorbability to laser light as necessary) or an alloy material containing ABS. To do. Examples of the ABS counterpart in the alloy material include AAS, PBT, PET, PMMA, PA (polyamide), PE (polyethylene), PP (polypropylene), and elastomer. In addition, a predetermined colorant such as carbon black, a dye, or a pigment is mixed in the body made of the ABS-based material, if necessary, so as to be an absorptive resin material having a predetermined absorbability with respect to the laser beam. In addition, if necessary, reinforcing fibers such as glass fibers and carbon fibers may be added.
[0035]
The PET-based material constituting the reflector means a PET material made of PET alone (added with a coloring material to give a predetermined absorbability to laser light as necessary) or an alloy material containing PET. . Examples of the PET counterpart in the alloy material include AAS, ABS, PBT, PMMA, PA (polyamide), PE (polyethylene), PP (polypropylene), and elastomer. Similarly, the PBT material constituting the reflector is a PBT material made of PBT alone (added with a coloring material to give a predetermined absorbability to laser light as necessary) or an alloy material containing PBT. means. Examples of the PBT counterpart material in the alloy material include AAS, ABS, PET, PMMA, PA (polyamide), PE (polyethylene), PP (polypropylene), and elastomer. It should be noted that a reflector made of a PET-based material or a PBT-based material has a predetermined coloring such as carbon black, a dye, or a pigment as necessary so as to be an absorptive resin material having a predetermined absorbability with respect to laser light. A material can be mixed, and if necessary, reinforcing fibers such as glass fibers and carbon fibers may be added.
[0036]
In the irradiation step, the laser beam is irradiated from the lens side toward the welding surface of the contact end portion of the reflector, and the laser beam reflected by the welding surface is transmitted through the contact end portion of the lens to By reaching the welding surface of the abutting end, it is possible to weld the lens and the reflectors and the lens and the bodies while suppressing the occurrence of stress cracks in the body.
[0037]
That is, a part of the laser light applied to the welding surface of the reflector from the lens side is absorbed by the welding surface of the reflector, and the rest is reflected by the welding surface and reaches the welding surface of the body. For this reason, the welding surface of the reflector is heated and melted, and the welding surface of the lens that contacts the welding surface is heated and melted by heat transfer from the welding surface of the reflector, so that the welding surfaces of the lens and the reflector can be welded to each other. Become. Further, the laser beam reflected by the welding surface of the reflector reaches the welding surface of the body and is absorbed, whereby the welding surface of the body is heated and melted, and the welding surface of the lens in contact with the welding surface is the body. It is heated and melted by heat transfer from the welding surface, and the welding surfaces of the lens and the body can be welded to each other.
[0038]
On the other hand, the PC material constituting the lens and the ABS material constituting the body are different materials, but are compatible materials with each other, so that laser welding is possible.
[0039]
In addition, ABS contained in the ABS material constituting the body is a material that hardly causes stress cracks, but is a material having a low melting point (about 170 ° C.) and low heat resistance as compared with PC. For this reason, the body made of ABS material can effectively eliminate the problem of stress cracking, but if the body made of ABS material is directly irradiated with laser light from the lens side, thermal deterioration is likely to occur. There's a problem. Even when the laser beam is directly applied to the body made of an ABS material from the lens side, the occurrence of thermal deterioration in the body can be suppressed by appropriately adjusting the laser irradiation conditions. However, in this case, due to insufficient heat input at the welding surface of the body and insufficient heat transfer from the welding surface to the welding surface of the lens, insufficient melting of the body and lens at the welding interface occurs, and sufficient welding strength can be ensured. Impossible or difficult.
[0040]
  This point, claims2In the described invention, the laser beam from the lens side is first irradiated to the reflector as described above, and the reflected light is transmitted through the abutting end of the lens and irradiated to the body. For this reason, compared with the case where the laser beam reaching the welding surface of the body is directly irradiated from the lens side, the amount absorbed by the welding surface of the reflector and the time during which the reflected light passes through the contact end portion of the lens. Therefore, the energy is reduced by the amount absorbed in the lens. Therefore, even if the body is made of an ABS-based material having low heat resistance, it is possible to effectively suppress thermal deterioration on the welding surface of the body.
[0041]
In addition, the contact end portion of the lens is formed when the laser beam irradiated from the lens side toward the welding surface of the reflector is directed to the welding surface, and when the reflected light reflected by the welding surface is directed to the welding surface of the body. The laser light is transmitted at least twice, and the internal heat generation is larger due to the greater number of times the reflected light is transmitted. That is, the contact end portion of the lens is preheated by the transmission of reflected light. For this reason, the amount of heat transfer from the welding surface of the body to the welding surface of the lens, which is necessary to ensure sufficient welding strength between the body and the lens, and thus the amount of heat input on the welding surface of the body is reduced by such preheating. Can do. Therefore, even when the amount of heat input on the welding surface of the body is reduced to a level that can prevent thermal degradation of the ABS, it is possible to sufficiently secure the welding strength between the body and the lens.
[0042]
  Therefore, the claim2According to the described invention, it is possible to suppress the occurrence of thermal degradation of the body while sufficiently ensuring the welding strength between the lens and the body, and to effectively suppress the occurrence of stress cracks in both the lens and the body. The problem of strength reduction due to the occurrence of the stress crack can be effectively suppressed.
[0043]
In addition, the reflector directly irradiated with laser light from the lens side is made of a PET-based material or a PBT-based material, and as described above, the PET-based material or the PBT-based material is a material that hardly generates stress cracks. The problem of stress cracks does not occur even when directly irradiated with laser light.
[0044]
In addition, since ABS used for the body is less expensive than PC, PET, PBT, etc., it is advantageous in terms of cost.
[0045]
Further, in the irradiation step, the lens and the reflectors and the lens and the body can be laser-welded at the same time by utilizing the reflection of the laser beam on the welding surface of the reflector. That is, the three components of the lens, the body, and the reflector can be integrally joined by one laser welding, which is advantageous in improving the productivity of the vehicular lamp.
[0046]
The type of laser light used as the heating source is a predetermined value for the transmittance in the transparent resin material in relation to the absorption spectrum, plate thickness (transmission length), etc. of the transparent resin material that transmits the laser light. What has the wavelength which becomes the above is selected suitably. For example, a YAG: Nd3 + laser (laser light wavelength: 1060 nm) or a semiconductor laser (laser light wavelength: 500 to 1000 nm) can be used.
[0047]
Further, irradiation conditions such as laser output, irradiation density, and processing speed (moving speed) can be appropriately set according to the type of resin.
[0048]
【Example】
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0049]
  Example 1
  The embodiment shown in FIGS.1The present invention embodies a laser welding method for a vehicle lamp, and claims the manufacture of an automotive headlight as a vehicle lamp.1This invention is applied.
[0050]
FIG. 1 is a perspective view of a car headlight cut, and FIG. 2 is a cross-sectional view of a main part showing a joining structure.
[0051]
As shown in FIG. 1, this headlight is a hollow body composed of a lens 1, a lamp body 2, a reflector (reflecting mirror) 3, a lamp 4, and a cover 5.
[0052]
The lens 1 is made of a transmissive resin material that is transmissive to laser light as a heating source, and specifically made of a PC material.
[0053]
The lamp body 2 is made of an absorptive resin material that absorbs laser light as a heating source, specifically, a PC-based material to which glass fiber is added in an appropriate amount in an amount of 30 wt% and carbon black as a colorant. (Alloy material of PC and PET).
[0054]
Then, the abutting end portion 10 of the lens 1 and the abutting end portion 20 of the body 2 are in contact with each other by laser welding.
[0055]
In addition, a reflector 3 made of epoxy (BMC) is disposed and fixed inside the body 2 with an adhesive or the like, and is inserted into through holes 2a and 3a that are formed in the rear walls of the body 2 and the reflector 3, respectively. The lamp 4 is disposed, and the through hole 2 a of the body 2 is closed with a cover 5.
[0056]
As shown in FIG. 2, the abutting end 10 of the lens 1 has a hollow portion inside the hollow body (the lower side of FIG. 2, the same applies hereinafter) and a hollow while leaving a stepped portion on the base end side (left end side of FIG. 2). The outside of the body (upper side in FIG. 2, the same applies hereinafter) is cut out in a tapered shape, and the tip is cut off, and a fitting projection 11 is provided which is formed so as to gradually shrink toward the tip and protrude. It has been. The fitting convex portion 11 includes a distal end surface 11a, inner and outer tapered outer surfaces 11b and 11c of the hollow body, and inner and outer stepped surfaces 11d and 11e intersecting the base ends of the tapered outer surfaces 11b and 11c. And have.
[0057]
On the other hand, the contact end 20 of the body 2 is formed in a shape that gradually expands and protrudes toward the distal end side (left end side in FIG. 2), and is a fitting recess 21 that can be fitted with the fitting protrusion 11. Is provided. The fitting recess 21 includes a bottom surface 21a aligned with the tip surface 11a, tapered inner surfaces 21b and 21c inside and outside the hollow body aligned with the tapered outer surfaces 11b and 11c, and tapered inner surfaces 21b. And 21c and 21c, and the inner and outer tip surfaces 21d and 21e of the hollow body that are aligned with the stepped surfaces 11d and 11e, respectively. The inner surface of the fitting recess 21 is constituted by the bottom surface 21a and the inner and outer tapered inner surfaces 21b and 21c.
[0058]
And the fitting convex part 11 of the lens 1 and the fitting concave part 21 of the body 2 are fitted, the front end surface 11a and the bottom face 21a, the inner taper outer surface 11b and the taper inner face 21b, and the outer taper. The outer surface 11c and the tapered inner surface 21c, the inner stepped surface 11d and the distal end surface 21d, and the outer stepped surface 11e and the distal end surface 21e are integrally joined by laser welding.
[0059]
In this embodiment, the front end surface 11a of the fitting convex portion 11, the tapered outer surfaces 11b and 11c and the stepped surfaces 11d and 11e, the bottom surface 21a of the fitting concave portion 21, the tapered inner surfaces 21b and 21c, and Each front end surface 21d, 21e becomes a welding surface to be welded by laser welding.
[0060]
The resin molded product of the present example having the above-described configuration was manufactured as follows.
[0061]
(Contact process)
First, the lens 1 and the body 2 were each formed into a predetermined shape by injection molding, and then a reflector was disposed and fixed on the inner surface of the body 2. Then, the contact end portion 10 of the lens 1 and the contact end portion 20 of the body 2 were brought into contact with each other, and the fitting convex portion 11 of the lens 1 and the fitting concave portion 21 of the body 2 were fitted.
[0062]
(Irradiation process)
In this state, a part of the bottom surface 21a of the fitting recess 21 of the body 2 (the lower part of FIG. 2 inside the hollow body), the entire inner tapered inner surface 21b, and the inner and outer tip surfaces 21d and 21e, respectively. The laser beam 6 was obliquely irradiated from the outside of the hollow body toward each surface on the lens 1 side as the transparent resin material so that the laser beam was incident on the surface from an oblique direction (see FIG. 2). The incident angle (θ) of the laser beam at the time of oblique irradiation is 30 degrees with respect to the bottom surface 21a of the fitting recess 21 and the respective tip surfaces 21d and 21e, and with respect to the tapered inner surface 21b inside the fitting recess 21. The angle was 45 degrees (see FIG. 3). Note that a part of the bottom surface 21a of the fitting recess 21 (the outer portion of the hollow body in FIG. 2 and the outer tapered inner surface 21c) is not directly irradiated with laser light, and the bottom surface 21a of the fitting recess 21 is not irradiated. The reflected light reflected from other portions or the inner tapered inner surface 21b was irradiated. Further, YAG-neodymium laser light (wavelength 1060 nm) was used as the laser light. Irradiation conditions were: output: 200 to 400 W, processing speed: 5 m / min.
[0063]
The laser irradiation irradiates the entire inner surface of the fitting recess 21, that is, the entire bottom surface 21 a and each of the tapered inner surfaces 21 b and 21 c, by utilizing the repetition of reflection on the inner surface of the fitting recess 21 by the laser irradiation. The welding surfaces of the fitting projections 11 and the welding surfaces of the fitting recesses 21 of the body 2 were heat-melted and welded together and integrally joined.
[0064]
In the joint portion thus obtained, the respective weld surfaces are melted and joined, and between the weld surfaces, both resins constituting both members are melted to enter each other and become entangled. It has a strong bonding state and a high pressure strength by constituting a strong bonding state.
[0065]
In addition, in this embodiment, in addition to joining by welding the respective welding surfaces of the fitting convex portion 11 and the respective welding surfaces of the fitting concave portion 21 by laser welding, the fitting convex portion 11 of the lens 1 and the fitting concave portion of the body 2. 21 and the engagement between the stepped surfaces 11d and 11e of the lens 1 and the front end surfaces 21d and 21e of the body 2 provide a structurally strong joint, and thus a higher joint strength. And withstand pressure strength.
[0066]
Further, in this embodiment, the lens 1 is made of a PC material, and the body 2 is made of a PC material, that is, an alloy material containing PC. For this reason, the presence of the PC included in both the lens 1 and the body 2 is advantageous in improving the welding strength of both.
[0067]
In the lens 1 made of a PC material, there is almost no internal heat generation during laser transmission due to the high transmittance of the PC, and it is heated and melted only by heat transfer from the body 2 on the laser absorption side, and only the interface with the body is present. Since it is melted and welded, there are almost no heat-affected zones and stress cracks hardly occur.
[0068]
On the other hand, if laser welding is performed on the body 2 made of a PC-based material by general vertical irradiation that has been conventionally performed, the occurrence of stress cracks becomes a problem.
[0069]
In this respect, in this embodiment, in the irradiation step, each welding surface of the body 2 (the bottom surface 21a of the fitting recess 21, the inner tapered inner surface 21b, and the inner and outer front end surfaces 21d and 21e). Laser light is obliquely irradiated. For this reason, compared to the case of vertical irradiation, the amount of laser light absorbed by each welding surface is reduced by the amount of laser light reflected by each welding surface, and laser irradiation is performed on each welding surface. This reduces the thermal effect caused by. Therefore, when trying to avoid a sudden temperature rise and excessive heat input on each welding surface of the body by setting the laser irradiation conditions as appropriate, even if there are some minor adjustment errors in the irradiation conditions, The welding surface temperature of the body 2 does not change greatly as in the case of irradiation, and it is easy to avoid a sudden temperature rise and excessive heat input. Therefore, the occurrence of stress cracks in the body 2 can be easily and effectively suppressed by simple adjustment of the irradiation conditions.
[0070]
Further, in this embodiment, the contact end portion 10 of the lens 1 made of a transparent resin is constituted by the fitting convex portion 11, and the contact end portion 20 of the body 2 made of the absorbent resin is made the fitting convex portion 11. And a fitting concave portion 21 that can be fitted, and obliquely irradiating a part of the inner surface of the fitting concave portion 21 with laser light, utilizing the repetition of reflection on the inner surface of the fitting concave portion 21, The entire inner surface is irradiated with laser light. For this reason, it is possible to effectively suppress a rapid temperature rise as a heat input state dispersed on the welding surface of the body 2 while reducing energy loss.
[0071]
In this embodiment, an alloy material of PC and PET is used as the PC material constituting the body 2, but in addition to this, a PC material made of a single PC (giving a predetermined absorbability for laser light). The same effect can be achieved even if an alloy material of AAS, ABS, PBT, PMMA, PA, PE, PP, or elastomer and PC is used.
[0072]
  (Reference example)
  BookReference examplesExcept for changing the resin material of Di 2, the configuration is the same as in Example 1.
[0073]
  Ie bookreferenceIn the headlight according to the example, the body 2 as the absorbent resin is made of a PET material.
[0074]
The PET material that constitutes the body 2 is a material in which stress cracks are unlikely to occur. For this reason, by adopting such a material for the body 2, even if the body 2 is laser welded to the lens 1 made of a PC material, almost no stress cracks are generated in the body 2. Therefore, the occurrence of stress cracks in the body 2 can be suppressed more effectively.
[0075]
Other functions and effects are the same as those of the first embodiment.
[0076]
  In addition, thisreferenceIn the example, a PET material is adopted as the resin material of the body 2, but instead of this, an PET material is used even if an alloy material of PET and ABS, or an alloy material of PBT material or PBT and ABS is adopted. It is possible to achieve the same effect as the case.
[0077]
In addition, when a resin material of the body 2 is an PET material or an alloy material of PET and ABS, or an alloy material of PBT material or PBT and ABS, the generation of stress cracks is suppressed by these material characteristics. Therefore, even when the laser beam is not irradiated obliquely, the occurrence of stress cracks in the body 2 can be effectively suppressed.
[0078]
  (Example2)
  This embodiment shown in FIG. 4 and FIG.2The present invention embodies a laser welding method for a vehicle lamp.
[0079]
In other words, in the present embodiment, the lens 1 is made of a transmissive resin that is transmissive to laser light as a heating source, and specifically made of a PC material.
[0080]
The body 2 is made of a transparent resin material that absorbs laser light as a heating source. Specifically, the body 2 is made of an ABS material to which 30% by weight of glass fiber and an appropriate amount of carbon black as a colorant are added.
[0081]
The reflector 3 is made of an absorptive resin material that absorbs laser light as a heating source, specifically, a PET material to which glass fiber is 30 wt% and carbon black as a colorant is appropriately added. It becomes more.
[0082]
The three contact end portions 10 and 20 are in contact with the contact end portion 10 of the lens 1, the contact end portion 20 of the body 2, and the contact end portion 30 of the reflector 3. And 30 are joined together by laser welding.
[0083]
Specifically, as shown in FIG. 5, the contact end portion 10 of the lens 1 is formed with a fitting convex portion 11 similar to that in the first embodiment.
[0084]
On the other hand, the contact end portion 20 of the body 2 has a shape in which a wall portion on the inner side (lower side in FIG. 5) of the fitting recess 21 shown in the first embodiment is cut out. That is, the fitting recess 21 of the body 2 is formed in a shape that gradually expands and protrudes toward the distal end side (left end side in FIG. 5), and one side (inside the hollow body, the lower side in FIG. 5). The end portion 11a of the fitting convex portion 11 and the second end surface (the end surface on the right side in FIG. 5) 30c of the contact end portion 30 of the reflector 3 are in contact with each other. The stepped bottom surface 21f, the outer tapered inner surface 21c that contacts and contacts the outer tapered surface 11c on the outer side (upper side in FIG. 5) of the fitting convex portion 11, and the tip of the tapered inner surface 21c intersect with the fitting convex portion. It has a stepped surface 11e on the outer side of the portion 11 and an outer tip surface 21e that abuts in alignment with each other.
[0085]
Further, the abutting end 30 of the reflector 3 is in contact with the tapered tip surface 30 a that is in contact with the tapered outer surface 11 b inside the fitting convex portion 11 and the stepped surface 11 d that is inside the fitting convex portion 11. It has a first side end face (the left end face in FIG. 5) 30b that abuts in alignment and the second side end face 30c.
[0086]
And the fitting convex part 11 of the lens 1 and the fitting recessed part 21 of the body 2 are fitted, and the reflector 3 is formed in the recessed part formed between the fitting convex part 11 fitted and the fitting recessed part 21. The fitting tip of the contact end 30 is fitted, the stepped surface 11 d inside the fitting convex 11 and the first side end surfaces 30 b of the reflector 3, and the tapered outer surface inside the fitting convex 11 11b and the inclined front end surfaces 30a of the reflector 3, the front end surface 11a of the fitting convex portion 11 and the stepped bottom surfaces 21f of the fitting concave portion 21, and the outer tapered surface 11c and the fitting concave portion 21 outside the fitting convex portion 11. The outer tapered inner surfaces 21c are integrally joined to each other by laser welding.
[0087]
In this embodiment, the front end surface 11a of the fitting convex portion 11, each tapered outer surface 11b, 11c, the inner stepped surface 11d, and a part of the stepped bottom surface 21e of the fitting concave portion 21 (stepped bottom surface). 21e), the outer tapered inner surface 21c, the first side end surface 30b and the inclined front end surface 30a of the reflector 3 are welded surfaces that are welded by laser welding.
[0088]
The resin molded product of the present example having the above-described configuration was manufactured as follows.
[0089]
(Contact process)
First, the lens 1, the body 2 and the reflector 3 are each formed into a predetermined shape by injection molding, and then the abutting end 10 of the lens 1 and the abutting end of the body 2 are disposed inside the body 2. 20 and the contact end portion 30 of the reflector 3 are brought into contact with each other, the fitting convex portion 11 of the lens 1 and the fitting concave portion 21 of the body 2 are fitted, and further between the fitting convex portion 11 and the fitting concave portion 21. The fitting tip part of the contact end part 30 of the reflector 3 was fitted.
[0090]
(Irradiation process)
In this state, from the outside of the hollow body on the lens 1 side as the transmissive resin material, the laser light is incident on each of the inclined front end surface 30a and the first side end surface 30b of the reflector 3 from an oblique direction. The laser beam 6 was obliquely irradiated toward each surface (see FIG. 5). The stepped bottom surface 21f, the outer tapered inner surface 21c, and the outer tip surface 21e of the fitting recess 21 were not irradiated with laser light. The stepped bottom surface 21 f and the outer tapered inner surface 21 c of the fitting recess 21 were irradiated with the reflected light reflected by the inclined tip surface 30 a of the reflector 3 and the like. Further, YAG-neodymium laser light (wavelength 1060 nm) was used as the laser light. Irradiation conditions were: output: 200 to 400 W, processing speed: 5 m / min.
[0091]
By irradiating the entire welding surface with laser light while utilizing the repetition of reflection on the stepped bottom surface 21f and the outer tapered inner surface 21c of the fitting recess 21 and the inclined front end surface 30a of the reflector 3 by the laser irradiation, The weld surfaces were melted by heating and welded together, and were joined together.
[0092]
In the joint portion thus obtained, the respective weld surfaces are melted and joined, and between the weld surfaces, both resins constituting both members are melted to enter each other and become entangled. It has a strong bonding state and a high pressure strength by constituting a strong bonding state.
[0093]
Further, in this embodiment, each welding surface of the fitting convex portion 11 and each welding surface of the fitting concave portion 21, each welding surface of the fitting convex portion 11, and each nuclear welding surface of the reflector 3 are joined by laser welding. In addition, the fitting convex portion 11 of the lens 1 and the fitting concave portion 21 of the body 2 are fitted, and the concave portion formed between the fitting convex portion and the fitting concave portion 21 and the fitting distal end portion of the reflector 3. Since it is a structurally strong joint due to the fitting, it has higher joint strength and pressure strength.
[0094]
In the lens 1 made of a PC material, there is almost no internal heat generation during laser transmission due to the high transmittance of the PC, and it is heated and melted only by heat transfer from the reflector 3 and the body 2 on the laser absorption side. Since only the interface with the body is melted and welded, there is almost no heat-affected zone and stress cracks hardly occur.
[0095]
On the other hand, in the body 2 made of ABS material and the reflector 3 made of PET material, stress cracks hardly occur due to these material characteristics.
[0096]
However, ABS, which constitutes the body 2, is advantageous in terms of cost because it is less expensive than PC, PET, PBT, and the like, but is a material with low heat resistance. For this reason, if the body 2 made of ABS material is directly irradiated with laser light, a problem of thermal degradation occurs.
[0097]
In this regard, in this embodiment, the laser beam is not directly irradiated on the welding surface of the body 2 in the irradiation step. That is, laser light is irradiated from the lens 1 side to the inclined tip surface 30a and the first side end surface 30b of the reflector 3, and the reflected light reflected by the inclined tip surface 30a is transmitted through the fitting convex portion 11 of the lens 1. The body 2 is irradiated with the stepped bottom surface 21f and the outer tapered inner surface 21c. For this reason, the amount of laser light that reaches the stepped bottom surface 21f and the outer tapered inner surface 21c of the body 2 is absorbed by the inclined tip surface 30a of the reflector 3 as compared with the case where it is directly irradiated from the lens 1 side. While the reflected light is transmitted through the fitting projection 11 of the lens 1, the energy is reduced by the amount absorbed in the fitting projection 11. Therefore, even if the body 2 is made of an ABS-based material having low heat resistance, it is possible to effectively suppress thermal deterioration on the welding surface of the body 2.
[0098]
In addition, the fitting convex portion 11 of the lens 1 is reflected when the laser light irradiated from the lens 1 toward the inclined tip surface 30a of the reflector 3 is directed to the inclined tip surface 30a and reflected by the inclined tip surface 30a. The laser light is transmitted at least twice when the light travels toward the welding surface of the body 2, and the internal heat generation is larger due to the greater number of times the reflected light is transmitted. That is, the fitting convex portion 11 of the lens 1 is in a preheated state by transmission of reflected light. For this reason, the amount of heat transfer from the welding surface of the body 2 to the welding surface of the lens 1 and the amount of heat input on the welding surface of the body 2 necessary for ensuring sufficient welding strength of the lens 1 and the body 2 by this preheating amount. Can be reduced. Therefore, even when the amount of heat input at the welding surface of the body 2 is reduced to a level that can prevent thermal degradation of the ABS, it is possible to sufficiently secure the welding strength between the body 1 and the lens 2. .
[0099]
Therefore, according to the present embodiment, it is possible to suppress the occurrence of thermal deterioration of the body 2 while sufficiently securing the welding strength between the lens 1 and the body 2, and to prevent stress cracks in both the lens 1 and the body 2. Generation | occurrence | production can be suppressed effectively and it becomes possible to suppress effectively the problem of the strength fall by this stress crack generation | occurrence | production.
[0100]
Further, in this embodiment, the three components of the lens 1, the body 2, and the reflector 3 can be integrally joined by one laser welding, which is advantageous in improving the productivity of the vehicular lamp.
[0101]
In this embodiment, an ABS material is used as the resin material of the body 2, but instead of this, an alloy material of AAS, PBT, PET, PMMA, PA, PE, PP or an elastomer and ABS is used. Also, it is possible to achieve the same effect as when the ABS material is employed.
[0102]
In this embodiment, a PET material is used as the resin material of the reflector 3, but instead of this, an alloy material of AAS, ABS, PBT, PMMA, PA, PE, PP or elastomer and PET, or PBT alone Even when a PBT material made of AAS, ABS, PET, PMMA, PA, PE, PP, or an alloy material of an elastomer and PBT is employed, the same effect as when the PET material is employed can be achieved.
[Brief description of the drawings]
FIG. 1 is a perspective view of an automotive headlight according to a first embodiment of the present invention cut.
FIG. 2 is a cross-sectional view of a main part showing a joining structure of an automotive headlight according to Embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view illustrating an incident angle of laser light with respect to a welding surface.
FIG. 4 is a perspective view of an automobile headlight according to a second embodiment of the present invention cut.
FIG. 5 is a cross-sectional view of a main part showing a joining structure of an automotive headlight according to a second embodiment of the invention.
[Explanation of symbols]
1 ... Lens 2 ... Lamp body (body)
3 ... Reflector 10, 20, 30 ... Contact end
11 ... Fitting convex part 21 ... Fitting concave part

Claims (2)

加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディとの当接端部同士を当接させる当接工程と、
上記レンズ側からの上記レーザ光の照射により、上記レンズの当接端部及び上記ボディの当接端部の各溶着面同士を加熱溶融させて溶着し、該レンズと該ボディとを一体的に接合する照射工程とからなる車両用灯具のレーザ溶着方法であって、
上記レンズはＰＣ材からなるとともに上記ボディはＰＣ系材からなり、かつ、該レンズの当接端部は嵌合凸部により構成されるとともに、該ボディの当接端部は該嵌合凸部と嵌合可能な嵌合凹部により構成され、
上記当接工程では、該嵌合凸部と該嵌合凹部とを嵌合させ、上記照射工程では、該ボディの当接端部の溶着面である該嵌合凹部の内面のうちの少なくとも一部に対して上記レーザ光を斜め照射することを特徴とする車両用灯具のレーザ溶着方法。Abutting ends of a lens made of a transparent resin material that is transparent to laser light as a heating source and a body made of an absorbent resin material that is absorbent to the laser light are brought into contact with each other. A contact process;
By irradiating the laser light from the lens side, the welding surfaces of the contact end portion of the lens and the contact end portion of the body are heated and melted to weld the lens and the body together. A laser welding method for a vehicular lamp comprising an irradiation process to be joined,
The lens is made of a PC material, the body is made of a PC-based material, and the contact end portion of the lens is configured by a fitting convex portion, and the contact end portion of the body is the fitting convex portion It is composed of a fitting recess that can be fitted with
In the contact step, the fitting convex portion and the fitting concave portion are fitted , and in the irradiation step, at least one of the inner surfaces of the fitting concave portion which is a welding surface of the contact end portion of the body. A laser welding method for a vehicular lamp characterized by obliquely irradiating the laser beam to the part . 加熱源としてのレーザ光に対して透過性のある透過性樹脂材からなるレンズと、該レーザ光に対して吸収性のある吸収性樹脂材からなるボディと、該レーザ光に対して吸収性のある吸収性樹脂材からなるリフレクタとの当接端部同士を当接させる当接工程と、
上記レンズ側からの上記レーザ光の照射により、上記レンズの当接端部、上記ボディの当接端部及び上記リフレクタの当接端部の各溶着面を加熱溶融させて溶着し、該レンズ、該ボディ及び該リフレクタを一体的に接合する照射工程とからなる車両用灯具のレーザ溶着方法であって、
上記レンズはＰＣ材からなり、上記ボディはＡＢＳ系材からなり、上記リフレクタはＰＥＴ系材又はＰＢＴ系材からなり、
上記照射工程では、上記レンズ側から上記リフレクタの上記当接端部の溶着面に向けて上記レーザ光を照射するとともに、該溶着面で反射したレーザ光を上記レンズの上記当接端部内を透過させて上記ボディの上記当接端部の溶着面に到達させることにより、該レンズ及び該リフレクタ同士並びに該レンズ及び該ボディ同士を溶着することを特徴とする車両用灯具のレーザ溶着方法。A lens made of a transparent resin material that is transparent to laser light as a heating source, a body made of an absorbent resin material that is absorbent to the laser light, and an absorptive material to the laser light A contact step of contacting the contact end portions with a reflector made of a certain absorbent resin material;
By irradiating the laser light from the lens side, the welding surfaces of the contact end portion of the lens, the contact end portion of the body, and the contact end portion of the reflector are heated and melted, and the lens, A laser welding method for a vehicular lamp comprising an irradiation step of integrally joining the body and the reflector,
The lens is made of PC material, the body is made of ABS material, the reflector is made of PET material or PBT material,
In the irradiation step, the laser light is irradiated from the lens side toward the welding surface of the contact end portion of the reflector, and the laser light reflected by the welding surface is transmitted through the contact end portion of the lens. A laser welding method for a vehicular lamp, wherein the lens and the reflector and the lens and the body are welded to each other by reaching the welding surface of the contact end portion of the body.
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