JP2004095526A

JP2004095526A - Defogger for vehicle headlight

Info

Publication number: JP2004095526A
Application number: JP2003109071A
Authority: JP
Inventors: Kinji Nagase; 長瀬　金二; Keiji Sano; 佐野　啓二; Saneaki Yoneyama; 米山　真晃
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2002-07-11
Filing date: 2003-04-14
Publication date: 2004-03-25

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defogger for a vehicle headlight with an improved defogging capability for preventing the fog due to moisture condensation at an inner surface of a lens. <P>SOLUTION: The vehicle headlight includes a housing 2, a storing chamber 5 for forming an image by a lens 3 focusing light to a front side opening of the housing 2, and bulbs 6H and 6L and reflectors 7H and 7L, stored in the storing chamber 5. The housing 2 and the lens 3 are configured to tightly close the storing chamber 5. A diaphragm 22 is also provided to the housing 2 for absorbing pressure changes in the storing chamber 5. The storing chamber 5 further includes an absorbent 25. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯に関し，特に，上記レンズ内面の曇り止めのための装置に関する。
【０００２】
【従来の技術】
従来，自動車用前照灯において，収容室に連なる通気孔をハウジングに設け，バルブの点灯及び消灯に伴う収容室の温度変化に応じ収容室を呼吸させて，前照灯各部の変形を回避しつゝ，レンズ内面の結露による曇りを防ごうとするものが特許文献１に開示されるように，既に知られている。
【０００３】
また自動車用前照灯において，ハウジングに設けられた通気孔と，バルブの上方でリフレクタ内面に開口する通気孔との間を通気ダクトで接続し，この通気ダクト内にシリカゲルのような再生可能な吸湿剤を配置し，バルブの点灯及び消灯に伴なうリフレクタ内の温度変化により，通気ダクトを通してハウジング内を呼吸させ，低温の外気を吸入するときに吸湿剤に吸湿を行わせてレンズ内面の曇りを防ぎ，高温の内気を排出するときに吸湿剤に再生を行わせるようにしたものも，特許文献２に開示されるように，既に知られている。
【０００４】
【特許文献１】
実公平７−５５７６８号公報
【特許文献２】
特開平９−１０２２０４号公報
【０００５】
【発明が解決しようとする課題】
ところが，特許文献１に開示されたものでも，収容室の呼吸作用により湿度の高い空気を吸入した場合には，レンズ内面に結露による曇りを生ずることがある。
【０００６】
また特許文献２に開示された，シリカゲルのような物理的に水分を取り込む抱水性の吸湿剤を用いものでは，吸湿した水分を比較的低温で放出してしまい，吸湿効果の持続性が極めて低く，満足する曇り止めを得ることが困難である。その上，抱水性の吸湿剤が湿気を吸収した状態のとき，バルブの点灯によりハウジング内が高温になると，吸湿剤が一旦吸収した水分をハウジング内に放出してハウジング内が多湿状態となるので，それを防ぐために，高温の内気を，吸湿剤の放出水分と共に排出する前述のような通気手段が不可欠となるが，その通気手段は，バルブの消灯により低温の外気を吸入するとき，同時に埃を引き込む弊害を招く虞がある。
【０００７】
本発明は，かゝる事情に鑑みてなされたもので，埃の侵入を防ぎつゝ，レンズ内面の曇り止め性能を大幅に改善した，自動車用前照灯の曇り止め装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記目的を達成するために，本発明は，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を密閉するように前記ハウジング及びレンズを構成すると共に，前記収容室の圧力変化を吸収する圧力調整手段を設けたことを第１の特徴とする。
【０００９】
尚，前記バルブは，後述する本発明の実施例中のハイビーム用バルブ６Ｈ及びロービーム用バルブ６Ｌに対応する。
【００１０】
この第１の特徴によれば，バルブの点灯及び消灯に起因して収容室の温度が激しく変化し，それに伴ない収容室の圧力が変化しても，その変化を圧力調圧手段が吸収することにより，収容室は外気を呼吸しなくても，常に略一定の圧力を保持することができ，したがって前照灯の各部に変形を来すことを回避しつゝ，収容室の外気の吸入を阻止して，レンズ内面の結露による曇りの発生を防ぐことができる。しかも密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入を防ぐことができる。
【００１１】
また本発明は，第１の特徴に加えて，前記圧力調整手段が，一側面を前記収容室に，他側面を大気にそれぞれ臨ませたダイヤフラムを備えることを第２の特徴とする。
【００１２】
この第２の特徴によれば，収容室の激しい圧力変化をダイヤフラムの変形により的確に吸収して，前照灯の各部に変形を来すことを回避しつゝ，レンズ内面の結露による曇りの発生を効果的に防ぐことができる。
【００１３】
さらに本発明は，第２の特徴に加えて，前記リフレクタの裏側で前記ハウジングに前記ダイヤフラムを取り付けたことを第３の特徴とする。
【００１４】
この第３の特徴によれば，ダイヤフラムの設置に，ハウジング及びリフレクタ間のデッドスペースを有効に利用して，前照灯の大型化を回避することができ，またダイヤフラムはリフレクタに隠れることができるから，レンズを通して外部から見られることがなく，外観を良好に保つことができる。
【００１５】
さらにまた本発明は，第２の特徴に加えて，前記圧力調整手段を，前記ハウジング外に設置されるケーシングと，このケーシング内を前記収容室に導管を介して連通する調圧室と，大気に連通する大気室との区画するダイヤフラムとで構成したことを第４の特徴とする。
【００１６】
この第４の特徴によれば，圧力調整手段を，前照灯から離隔した適所に自由に設置することが可能であり，汎用性が高い。
【００１７】
さらにまた本発明は，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を，少なくともその低温時に密閉するように前記ハウジング及びレンズを構成すると共に，この収容室に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤を配置したことを第５の特徴とする。
【００１８】
この第５の特徴によれば，バルブの交換等により，収容室に湿った空気が侵入し，収容室の湿度が上がったときには，吸湿剤が収容室内の湿気を吸収することで，レンズ内面の結露による曇りの発生を防ぐことができる。しかも該吸湿剤は，化学的に吸湿する吸湿材料で構成されるので，バルブの点灯により収容室が高温状態となっても吸収した湿気を放出せず，レンズ内面の再結露を防ぐことができ，また低温時には，密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入をも防ぐことができる。
【００１９】
さらにまた本発明は，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を密閉するように前記ハウジング及びレンズを構成すると共に，前記収容室の圧力変化を吸収する圧力調整手段を設け，さらに前記収容室に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤を配置したことを第６の特徴とする。
【００２０】
この第６の特徴によれば，収容室に対する圧力調圧手段の調圧作用と，吸湿剤の吸湿作用とにより，前照灯各部の変形を回避しつゝ，レンズ内面の結露による曇りの発生をより効果的に防ぐことができる。しかも該吸湿剤は，化学的に吸湿して再生能を持たない吸湿材料で構成されるので，バルブの点灯により収容室が高温状態となっても吸収した湿気を放出せず，レンズ内面の再結露を防ぐことができ，また密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入をも防ぐことができる。
【００２１】
さらにまた本発明は，第５又は第６の特徴に加えて，前記吸湿剤を，前記ハウジングに着脱可能に取り付けられるホルダに装着したことを第７の特徴とする。
【００２２】
この第７の特徴によれば，ホルダをハウジングから引き出すことにより，吸湿剤を簡単に交換することができ，したがって，例えばバルブの交換時や，車両の法定検査時に吸湿剤を交換することにより，吸湿剤の機能を常に発揮させて収容室を低湿度に保ち，レンズ内面の結露による曇りの発生を確実に防ぐことができる。
【００２３】
さらにまた本発明は，第５〜第７の特徴の何れかに加えて，前記吸湿剤を，前記バルブから放射された光が前記リフレクタで反射されて前記レンズから出射されるまでの光路外に配置したことを第８の特徴とする。
【００２４】
この第８の特徴によれば，バルブから放射された光は吸湿剤に全く干渉されることなく，その殆どがレンズを通して出射され，バルブの放射光を無駄なく有効に利用することができる。また前照灯の設計に当たっては，従来の配光特性等の光学設計と同様の設計時間で済み，余分な設計工数を必要とせず，設計時間に短縮を図ることができる。
【００２５】
さらにまた本発明は，第５〜第８の特徴の何れかに加えて，前記吸湿剤を，酸化マグネシウム及び塩化マグネシウムの少なくとも一方を主成分とする吸湿材料で構成したことを第９の特徴とする。
【００２６】
この第９の特徴によれば，前記吸湿剤は，シリカゲルを材料とする吸湿剤に比して吸湿性能が極めて高く，少量でもレンズ内面の曇りを防ぐことができるので，その設置スペースが狭くて足り，前照灯のコンパクト化に寄与し得る。
【００２７】
【発明の実施の形態】
本発明の実施の形態を，添付図面に示す本発明の実施例に基づいて以下に説明する。
【００２８】
図１は本発明の第１実施例に係る自動車用前照灯の正面図，図２は図１の２−２線拡大断面図，図３は上記前照灯に装着される吸湿剤及び吸湿剤ホルダの分解斜視図，図４は本発明の第２実施例を示す，第２図との対応図，図５は本発明の第３実施例を示す，図２との対応図，図６は本発明の第４実施例を示す，図２との対応図，図７は本発明の吸湿剤と従来の吸湿剤（シリカゲル）との吸湿性能比較線図である。
【００２９】
先ず，図１〜図３に示す本発明の第１実施例の説明より始める。
【００３０】
図１及び図２において，参照符号１は自動車の左側の前照灯であり，右側の前照灯はそれと対称的な構成であるから，図から省略する。この前照灯１のハウジング２は，前面を開放した椀状をなしており，その前面開放端にシール部材４を介してレンズ３が結合される。これらハウジング２及びレンズ３により密閉した横長の収容室５が画成され，この収容室５に車両内側からハイビーム用バルブ６Ｈ，ロービーム用バルブ６Ｌ及びターンシグナル用バルブ６Ｔと，各バルブ６Ｈ，６Ｌ，６Ｔを囲繞するリフレクタ７Ｈ，７Ｌ，７Ｔと，各リフレクタ７Ｈ，７Ｌ，７Ｔの前面開口部間を仕切る一体型の仕切りフード８とが収容され，この仕切りフード８は，ハウジング２及びレンズ３間に挟持される。
【００３１】
各リフレクタ７Ｈ，７Ｌ，７Ｔはハウジング２に，それとの間に間隙９を存して，図示しない支持腕を介して支持され，また各リフレクタ７Ｈ，７Ｌ，７Ｔと仕切りフード８間にも間隙１０が設けられる。こうしてリフレクタ７Ｈ，７Ｌ，７Ｔ及び仕切りフード８により，収容室５には，ハイビーム用バルブ６Ｈを収容する第１バルブ室１２Ｈ，ロービーム用バルブ６Ｌを収容する第２バルブ室１２Ｌ及びターンシグナル用バルブ６Ｔを収容する第３バルブ室１２Ｔの三室が区画されるが，これら三室１２Ｈ，１２Ｌ，１２Ｔは，各リフレクタ７Ｈ，７Ｌ，７Ｔと仕切りフード８との間隙１０を介して相互に連通すると共に，ハウジング２と各リフレクタ７Ｈ，７Ｌ，７Ｔとの間の空間にも連通することになる。
【００３２】
リフレクタ７Ｈ，７Ｌ，７Ｔの後壁には，バルブ６Ｈ，６Ｌ，６Ｔに対応してバルブ挿入口１３Ｈ，１３Ｌ，１３Ｔが開口しており，これらバルブ挿入口１３Ｈ，１３Ｌ，１３Ｔにバルブ６Ｈ，６Ｌ，６Ｔをそれぞれ装着したソケット１４Ｈ，１４Ｌ，１４Ｔが着脱可能に取り付けられる。またハウジング２の後壁には，各ソケット１４Ｈ，１４Ｌ，１４Ｔに対応してキャップ取り付け口１５Ｈ，１５Ｌ，１５Ｔが開口しており，これらキャップ取り付け口１５Ｈ，１５Ｌ，１５Ｔにソケット１４Ｈ，１４Ｌ，１４Ｔを保持したキャップ１６Ｈ，１６Ｌ，１６Ｔが嵌装される。
【００３３】
ハウジング２には，リフレクタ７Ｈ，７Ｌ，７Ｔの裏側の適所において，収容室５の圧力変化を吸収する圧力調整手段２０が設けられる。この圧力調整手段２０は，リフレクタ７Ｈ，７Ｌ，７Ｔの裏側でハウジング２の適所に設けられた開口部２１を閉鎖しながら内側面を収容室５に臨ませるダイヤフラム２２を備えており，このダイヤフラム２２の外側面を覆うカバー２３がダイヤフラム２２と共にビス２８により固着され，このカバー２３には，ダイヤフラム２２の外側面を大気に連通する通気孔２４が穿設される。
【００３４】
また収容室５には，リフレクタ７Ｈ，７Ｌ，７Ｔの裏側の適所において，収容室５の吸湿を行う吸湿剤２５が配設される。この吸湿剤２５は，ハウジング２の適所に設けられた開口部３５にシール部材２９を介してバヨネット結合される吸湿剤ホルダ２６に保持される。即ち，図３に示すように，吸湿剤ホルダ２６は，収容室５に挿入される一対の挟持腕２６ａ，２６ａを備えており，これら挟持腕２６ａ，２６ａの，鋸歯状の滑り止め２７，２７をそれぞれ形成した対向面によって吸湿剤２５が挟持されるのである。
【００３５】
上記吸湿剤２５は，化学的に吸湿して再生能を持たず，且つ潮解性し難い吸湿材料で構成される。具体的には，吸湿剤２５は，酸化マグネシウム及び塩化マグネシウムの少なくとも一方を主成分とする吸湿材料で構成され，望ましくは，酸化マグネシウム及び塩化マグネシウムを主成分とし，混合比率を重量％で５０対５０〜７０対３０とした吸湿材料で構成される。
【００３６】
以上のように構成することで，圧力調整手段２０及び吸湿剤２５は，バルブ６Ｈ，６Ｌから放射された光が前記リフレクタ７Ｈ，７Ｌで反射されてレンズ３から出射されるまでの光路外に配置される。
【００３７】
次に，この第１実施例の作用について説明する。
【００３８】
ロービーム用バルブ６Ｌ又はハイビーム用バルブ６Ｈは，その点灯時にかなり高い熱を発するので，収容室５は高温となって圧力を上昇させ，また消灯時には，その熱の放散により圧力を降下させるが，その圧力上昇時にはダイヤフラム２２がカバー２３側へ撓むことにより，収容室５の有効容積を拡大して，上記圧力の上昇分を吸収し，また圧力降下時には，ダイヤフラム２２が収容室５側へ撓むことにより，収容室５の有効容積を縮小して，上記圧力の降下分を吸収する。したがって，収容室５の激しい温度変化にも拘らず，収容室５は外気を呼吸しなくても，常に略一定の圧力に保持されるから，前照灯１の各部に変形を来すことを回避することができ，また収容室５が湿度の高い外気を吸入することもないから，レンズ３内面の結露による曇りの発生を防ぐことができる。勿論，密閉状態の収容室５は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入を防ぐことができる。
【００３９】
しかも上記ダイヤフラム２２は，リフレクタ７Ｈ，７Ｌ，７Ｔの裏側においてハウジング２に取り付けられるので，ダイヤフラム２２の設置に，ハウジング２及びリフレクタ７Ｈ，７Ｌ，７Ｔ間のデッドスペースを有効に利用して，前照灯１の大型化を回避することができ，またダイヤフラム２２はリフレクタ７Ｈ，７Ｌ，７Ｔに隠れることができるから，レンズ３を通して外部から見られることがなく，外観を良好に保つことができる。
【００４０】
ロービーム用バルブ６Ｌ，その他のバルブの交換等により，収容室５に湿った外気が流入し，収容室５の湿度が上がったときには，収容室５に配設された吸湿剤２５が収容室５内の湿気を吸収するので，これによってもレンズ３内面の結露による曇りの発生を防ぐことができる。この吸湿剤２５は，ハウジング２に着脱可能に装着される吸湿剤ホルダ２６に保持されるので，吸湿剤ホルダ２６をハウジング２から引き出すことで，吸湿剤２５を簡単に交換することができ，したがって，例えばバルブ６Ｈ，６Ｌ，６Ｔの交換時や，車両の法定検査時に吸湿剤２５を交換することにより，吸湿剤２５の機能を常に発揮させて収容室５を低湿度に保ち，レンズ３内面の結露による曇りの発生を確実に防ぐことができる。
【００４１】
またハイビーム用バルブ６Ｈ，ロービーム用バルブ６Ｌ及びターンシグナル用バルブ６Ｔをそれぞれ配置する第１，第２，第３バルブ室１２Ｈ，１２Ｌ，１２Ｔは相互に連通すると共に，各リフレクタ７Ｈ，７Ｌ，７Ｔとハウジング２との間の空間とも連通しているから，第１，第２，第３バルブ室１２Ｈ，１２Ｌ，１２Ｔに対して単一の圧力調整手段２０及び吸湿剤２５を共通に使用することができ，構造の簡素化を図ることができる。
【００４２】
また特に，圧力調圧手段２０及び吸湿剤２５を併設することは，収容室５に対する圧力調圧手段の調圧作用と，吸湿剤２５の吸湿作用とにより，前照灯１各部の変形を回避しつゝ，レンズ３内面の結露による曇りの発生をより効果的に防ぐ上で極めて有効である。
【００４３】
図７は，本発明の上記吸湿剤２５を，酸化マグネシウム及び塩化マグネシウムを重量％で６０対４０とした吸湿材料で構成した場合の吸湿率と，シリカゲルよりなる従来の吸湿剤の吸湿率との比較テストをＪＩＳ　Ｚ０７０１の試験方法に基づき実施した結果を示す。
【００４４】
同図から明らかなように，５°Ｃ／３５％ＲＨ（湿度），２５°Ｃ／２０％ＲＨ，２５°Ｃ／５０％ＲＨ，２５°Ｃ／９０％ＲＨの四種類の環境下において，本発明の吸湿剤２５は，従来の吸湿剤に対して約２〜４倍の吸湿率を有することが確認された。また図示はしないが，６０°Ｃ／９５％ＲＨの環境下では約１４倍もの吸湿率を持つことも確認された。
【００４５】
このように本発明の吸湿剤２５の吸湿率が極めて高いことは，吸湿剤２５が少量でもレンズ３内面の曇りを防ぐことができることを意味し，その設置スペースが狭くて足り，前照灯のコンパクト化に寄与し得る。しかも上記吸湿剤２５は再生能を持たないから，密閉状態の収容室５では，温度変化による再結露を防ぐことができる。
【００４６】
また圧力調整手段２０及び吸湿剤２５は，バルブ６Ｈ，６Ｌから放射された光が前記リフレクタ７Ｈ，７Ｌで反射されてレンズ３から出射されるまでの光路外に配置されることで，バルブ６Ｈ，６Ｌから放射された光は吸湿剤に全く干渉されることなく，その殆どがレンズ３を通して出射されるから，バルブ６Ｈ，６Ｌの放射光を無駄なく有効に利用することができる。また前照灯の設計に当たっては，従来の配光特性等の光学設計と同様の設計時間で済み，余分な設計工数を必要としない。また特許文献２に開示されたものゝようには収容室５の呼吸を配慮する必要がないから，設計の自由度が阻害されず，設計時間の短縮と相俟って，設計コストの低減を図ることができる。
【００４７】
また化学的に吸湿し得る吸湿吸湿材料には潮解性を示すものも存在するが，本発明の吸湿剤２５は，潮解性を示し難い酸化マグネシウム及び塩化マグネシウムを主成分とする天然系の吸湿材料で構成されるので，それは潮解し難い天然系の材料であり，廃棄物として処理する場合でも，環境に与える影響が小さいものとすることができる。
【００４８】
次に，図４に示す本発明の第２実施例について説明する。
【００４９】
この第２実施例では，圧力調整手段２０は前照灯１から離隔した場所，例えばエンジンルームに設置される。この場合の圧力調整手段２０は，ケーシング３０と，このケーシング３０の内周壁に取り付けられて，その内部を調圧室３１と大気室３２とに区画するダイヤフラム２２とで構成され，調圧室３１は可撓性の導管３３を介して前照灯１の収容室５に連通され，大気室３２はケーシング３０の通気孔３４を介して大気に開放される。その他の構成は，前実施例と同等であるので，図４中，前実施例と対応する部分には同一の参照符号を付して，その説明を省略する。
【００５０】
この第２実施例によれば，圧力調整手段２０を，前照灯１から離隔した適所に自由に設置することが可能であるから，汎用性が高い。
【００５１】
次に，図５に示す本発明の第３実施例について説明する。
【００５２】
この第５実施例では，ハウジング２の背面に，前記キャップ取り付け口１５Ｈ，１５Ｌ，１５Ｔを避けて装着孔４０が設けられ，この装着孔４０に，吸湿剤２５を内面に付設した有底円筒状の吸湿剤保持キャップ４１が着脱可能に装着される。
【００５３】
その他の構成は，前記第１実施例と同等であるので，図５中，第１実施例と対応する部分には同一の参照符号を付して，その説明を省略する。
【００５４】
この第３実施例によれば，ハウジング２の比較的広い背面を利用して，比較的大型の吸湿剤保持キャップ４１の取り付けが可能となり，したがって該キャップ４１に保持させる吸湿剤２５の量を大幅に調節することができる。
【００５５】
最後に，図６に示す本発明の第４実施例について説明する。
【００５６】
この第４実施例では，圧力調整手段２０は，シリンダ４２と，このシリンダ４２内にシール部材４４を介して摺動可能に嵌合して，その内部を調圧室３１と大気室３２とに区画するピストン４３とで構成され，調圧室３１は可撓性の導管３３を介して前照灯１の収容室５に連通され，大気室３２はシリンダ４２の端面から大気に開放される。ピストン４３は，その挿入，離脱時に操作されるピストンロッド４３ａを備える。
【００５７】
また吸湿剤２５は，前照灯１を自動車に取り付けた場合，外部から見えない位置，例えば仕切りフード８の裏面に接着される。したがって，この吸湿剤２５は，前照灯１の組立工程において，ハウジング２にレンズ３を取り付ける直前に，仕切りフード８の裏面に接着しなければならない。
【００５８】
その他の構成は，前記第１実施例と同様であるので，図６中，第１実施例と対応する部分には同一の参照符号を付して，その説明を省略するが，この第４実施例においては，前照灯１の使用初期段階では，ハウジング２に吸湿剤ホルダ２６を取り付けず，その装着用の開口部３５に単に密閉栓を施しておくだけでもよく，また吸湿剤ホルダ２６を取り付けておく場合であっても，該ホルダ２６に当初から吸湿剤２５を保持させておく必要はない。
【００５９】
この第４実施例によれば，バルブ６Ｌ，バルブ６Ｈの点灯及び消灯に伴なう収容室５の温度変化による圧力変動時には，ピストン４３がシリンダ４２内を進退して，調圧室３１の容積を変動させることで，収容室５の圧力変動を吸収して，前照灯１の各部に変形を来すことを回避することができる。このようにシリンダ４２及びピストン４３からなる圧力調整手段２０は，部品点数がすくなく，構造が簡単であるから，これを安価に提供することができる。
【００６０】
また吸湿剤２５は，前照灯１の組立工程において，ハウジング２にレンズ３を取り付ける直前に，仕切りフード８の裏面に接着されるので，仕切りフード８及びレンズ３間の狭小なスペースを利用して吸湿剤２５の設置が可能となり，吸湿剤２５がレンズ３に近接配置されることで，レンズ３内面での結露を効果的に防ぐことができる。
【００６１】
本発明は上記実施例に限定されるものではなく，その要旨を逸脱しない範囲で種々の設計変更が可能である。例えば，第１，第２，第３バルブ室１２Ｈ，１２Ｌ，１２Ｔを個別に密閉状に構成した場合には，各バルブ室１２Ｈ，１２Ｌ，１２Ｔに個別に圧力調整手段２０を接続することもでき，若しくは各バルブ室１２Ｈ，１２Ｌ，１２Ｔの境界部に共通の圧力調整手段２０を配設することもできる。またターンシグナル用バルブ６Ｔは前照灯１から除外することもできる。また本発明は，ハイビーム用バルブ６Ｈ及びロービーム用バルブ６Ｌをシングル型に構成した前照灯にも適用が可能である。
【００６２】
また上記各実施例では，圧力調整手段２０及び吸湿剤２５の両方により，レンズ３内面の結露による曇りを防ぐようにしたが，圧力調整手段２０及び吸湿剤２５の何れか一方によりレンズ３内面の結露による曇りを防ぐようすることもできる。吸湿剤２５のみを設ける場合には，収容室５の高温時には過剰圧力を逃がし，低温時には外気の吸入を阻止する一方弁をハウジング２に設けることは，前照灯１の変形防止とレンズ３の曇り止めとの両立を図る上で有効である。
【００６３】
【発明の効果】
以上のように本発明の第１の特徴によれば，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を密閉するように前記ハウジング及びレンズを構成すると共に，前記収容室の圧力変化を吸収する圧力調整手段を設けたので，バルブの点灯及び消灯に起因して収容室の温度が激しく変化し，それに伴ない収容室の圧力が変化しても，その変化を圧力調圧手段が吸収することにより，収容室は外気を呼吸しなくても，常に略一定の圧力を保持することができ，したがって前照灯の各部に変形を来すことを回避しつゝ，収容室の外気の吸入を阻止して，レンズ内面の結露による曇りの発生を防ぐことができる。しかも密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入を防ぐことができる。
【００６４】
また本発明の第２の特徴によれば，第１の特徴に加えて，前記圧力調整手段が，一側面を前記収容室に，他側面を大気にそれぞれ臨ませたダイヤフラムを備えるので，収容室の激しい圧力変化をダイヤフラムの変形により的確に吸収して，前照灯の各部に変形を来すことを回避しつゝ，レンズ内面の結露による曇りの発生を効果的に防ぐことができる。
【００６５】
さらに本発明の第３の特徴によれば，第２の特徴に加えて，前記リフレクタの裏側で前記ハウジングに前記ダイヤフラムを取り付けたので，ダイヤフラムの設置に，ハウジング及びリフレクタ間のデッドスペースを有効に利用して，前照灯の大型化を回避することができ，またダイヤフラムはリフレクタに隠れることができるから，レンズを通して外部から見られることがなく，外観を良好に保つことができる。
【００６６】
さらにまた本発明の第４の特徴によれば，第２の特徴に加えて，前記圧力調整手段を，前記ハウジング外に設置されるケーシングと，このケーシング内を前記収容室に導管を介して連通する調圧室と，大気に連通する大気室との区画するダイヤフラムとで構成したので，圧力調整手段を，前照灯から離隔した適所に自由に設置することが可能であり，汎用性が高い。
【００６７】
さらにまた本発明の第５の特徴によれば，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を，少なくともその低温時に密閉するように前記ハウジング及びレンズを構成すると共に，この収容室に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤を配置したので，バルブの交換等により，収容室に湿った外気が流入し，収容室の湿度が上がったときには，吸湿剤が収容室内の湿気を吸収することで，レンズ内面の結露による曇りの発生を防ぐことができる。しかも該吸湿剤は，化学的に吸湿する吸湿材料で構成されるので，バルブの点灯により収容室が高温状態となっても吸収した湿気を放出せず，レンズ内面の再結露を防ぐことができ，また低温時には，密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入をも防ぐことができる。
【００６８】
さらにまた本発明の第６の特徴によれば，ハウジングと，このハウジングの前面開口部に結合されるレンズとで画成される収容室に，バルブ及びリフレクタを収容してなる自動車用前照灯において，前記収容室を密閉するように前記ハウジング及びレンズを構成すると共に，前記収容室の圧力変化を吸収する圧力調整手段を設け，さらに前記収容室に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤を配置したので，収容室に対する圧力調圧手段の調圧作用と，吸湿剤の吸湿作用とにより，前照灯各部の変形を回避しつゝ，レンズ内面の結露による曇りの発生をより効果的に防ぐことができる。しかも該吸湿剤は，化学的に吸湿して再生能を持たない吸湿材料で構成されるので，バルブの点灯により収容室が高温状態となっても吸収した湿気を放出せず，レンズ内面の再結露を防ぐことができ，また密閉状態の収容室は外気を吸入しないから，吸湿剤の機能を特別増強する必要もなく，埃の侵入をも防ぐことができる。
【００６９】
さらにまた本発明の第７の特徴によれば，第５又は第６の特徴に加えて，前記吸湿剤を，前記ハウジングに着脱可能に取り付けられるホルダに装着したので，ホルダをハウジングから引き出すことにより，吸湿剤を簡単に交換することができ，したがって，例えばバルブの交換時や，車両の法定検査時に吸湿剤を交換することにより，吸湿剤の機能を常に発揮させて収容室を低湿度に保ち，レンズ内面の結露による曇りの発生を確実に防ぐことができる。
【００７０】
さらにまた本発明の第８の特徴によれば，第５〜第７の特徴の何れかに加えて，前記吸湿剤を，前記バルブから放射された光が前記リフレクタで反射されて前記レンズから出射されるまでの光路外に配置したので，バルブから放射された光は吸湿剤に全く干渉されることなく，その殆どがレンズを通して出射され，バルブの放射光を無駄なく有効に利用することができる。また前照灯の設計に当たっては，従来の配光特性等の光学設計と同様の設計時間で済み，余分な設計工数を必要とせず，設計時間に短縮を図ることができる。
【００７１】
さらにまた本発明の第９の特徴によれば，第５〜第８の特徴の何れかに加えて，前記吸湿剤を，酸化マグネシウム及び塩化マグネシウムの少なくとも一方を主成分とする吸湿材料で構成したので，前記吸湿剤は，シリカゲルを材料とする吸湿剤に比して吸湿性能が極めて高く，少量でもレンズ内面の曇りを防ぐことができるので，その設置スペースが狭くて足り，前照灯のコンパクト化に寄与し得る。
【図面の簡単な説明】
【図１】本発明の第１実施例に係る自動車用前照灯の正面図
【図２】図１の２−２線拡大断面図
【図３】上記前照灯に装着される吸湿剤及び吸湿剤ホルダの分解斜視図
【図４】本発明の第２実施例を示す，第２図との対応図
【図５】本発明の第３実施例を示す，図２との対応図
【図６】本発明の第４実施例を示す，図２との対応図
【図７】本発明の吸湿剤と従来の吸湿剤（シリカゲル）との吸湿性能比較線図
【符号の説明】
１・・・・・前照灯
２・・・・・ハウジング
３・・・・・レンズ
５・・・・・収容室
６Ｈ・・・・バルブ（ハイビーム用バルブ）
６Ｌ・・・・バルブ（ロービーム用バルブ）
７Ｈ・・・・リフレクタ（ハイビーム用リフレクタ）
６Ｌ・・・・リフレクタ（ロービーム用リフレクタ）
２０・・・・圧力調整手段
２２・・・・ダイヤフラム
２５・・・・吸湿剤
２６・・・・ホルダ
３０・・・・ケーシング
３１・・・・調圧室
３２・・・・大気室
３３・・・・導管[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a headlamp for an automobile in which a bulb and a reflector are accommodated in an accommodation room defined by a housing and a lens connected to a front opening of the housing. It relates to a device for stopping.
[0002]
[Prior art]
Conventionally, in an automotive headlamp, a ventilation hole connected to the housing chamber is provided in the housing, and the housing chamber is breathed according to the temperature change of the housing chamber when the valve is turned on and off, thereby avoiding deformation of each part of the headlight. First, as disclosed in Japanese Patent Application Laid-Open Publication No. HEI 10-163, there is already known an apparatus that attempts to prevent fogging due to condensation on the inner surface of a lens.
[0003]
Also, in a headlight for an automobile, a ventilation duct is used to connect the ventilation hole provided in the housing and the ventilation hole opening on the inner surface of the reflector above the bulb. A moisture absorbent is arranged, and the temperature inside the reflector is changed by turning on and off the bulb, and the inside of the housing is breathed through the ventilation duct. When the low temperature outside air is inhaled, the moisture absorbent absorbs moisture and the inside of the lens is removed. A device that prevents fogging and allows a moisture absorbent to regenerate when exhausting high-temperature inside air is already known as disclosed in Patent Document 2.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 7-55768
[Patent Document 2]
JP-A-9-102204
[0005]
[Problems to be solved by the invention]
However, even in the case disclosed in Patent Document 1, when high-humidity air is inhaled by the respiration of the storage chamber, fogging may occur on the inner surface of the lens due to condensation.
[0006]
Further, in the case of using a water-absorbing hygroscopic agent such as silica gel that physically takes in moisture as disclosed in Patent Document 2, the moisture absorbed is released at a relatively low temperature, and the durability of the moisture absorbing effect is extremely low. ， It is difficult to obtain satisfactory anti-fog. In addition, when the interior of the housing becomes hot due to the operation of the bulb when the hydrated absorbent absorbs moisture, the moisture absorbed by the absorbent is released into the housing and the interior of the housing becomes humid. In order to prevent this, it is essential to use the above-mentioned ventilation means for discharging the high-temperature inside air together with the moisture released from the desiccant. There is a risk of causing adverse effects of drawing in.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an anti-fog device for a headlight for an automobile, which prevents intrusion of dust and greatly improves the anti-fog performance on the inner surface of a lens. Aim.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an automotive headlamp in which a bulb and a reflector are accommodated in an accommodation room defined by a housing and a lens connected to a front opening of the housing. The first feature is that the housing and the lens are configured so as to seal the accommodation chamber, and pressure adjusting means for absorbing a pressure change in the accommodation chamber is provided.
[0009]
The valves correspond to a high beam valve 6H and a low beam valve 6L in an embodiment of the present invention described later.
[0010]
According to the first feature, even if the temperature of the storage chamber changes drastically due to the turning on and off of the valve and the pressure of the storage chamber changes accordingly, the change is absorbed by the pressure regulating means. This allows the containment chamber to maintain a substantially constant pressure at all times without breathing the outside air, thus avoiding deformation of the headlamp parts while inhaling the outside air from the containment chamber. And fogging due to condensation on the inner surface of the lens can be prevented. In addition, since the closed accommodation chamber does not inhale the outside air, it is not necessary to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0011]
According to a second feature of the present invention, in addition to the first feature, the pressure adjusting means includes a diaphragm having one side surface facing the accommodation chamber and the other side facing the atmosphere.
[0012]
According to the second feature, the violent pressure change in the housing chamber is accurately absorbed by the deformation of the diaphragm to avoid deformation of each part of the headlamp. Generation can be effectively prevented.
[0013]
Further, according to the present invention, in addition to the second feature, a third feature is that the diaphragm is attached to the housing on the back side of the reflector.
[0014]
According to the third feature, the dead space between the housing and the reflector can be effectively used for the installation of the diaphragm, so that the headlight can be prevented from being enlarged, and the diaphragm can be hidden by the reflector. Therefore, the appearance can be kept good without being seen from the outside through the lens.
[0015]
Still further, according to the present invention, in addition to the second feature, the pressure adjusting means includes a casing installed outside the housing, a pressure regulating chamber communicating the interior of the casing with the accommodation chamber via a conduit, and A fourth feature is that the air chamber communicates with the diaphragm and the diaphragm is partitioned.
[0016]
According to the fourth feature, it is possible to freely install the pressure adjusting means in an appropriate place separated from the headlight, and the versatility is high.
[0017]
Still further, the present invention provides an automotive headlamp in which a bulb and a reflector are accommodated in an accommodation room defined by a housing and a lens connected to a front opening of the housing, wherein the accommodation room includes: A fifth feature is that the housing and the lens are configured so as to be hermetically sealed at least at the low temperature, and a hygroscopic agent made of a hygroscopic material that does not have a regenerative ability by chemically absorbing moisture is disposed in the housing chamber. And
[0018]
According to the fifth feature, when moist air enters the accommodation room due to replacement of a valve or the like and the humidity of the accommodation room rises, the hygroscopic agent absorbs moisture in the accommodation room, so that the inner surface of the lens is removed. Clouding due to condensation can be prevented. Moreover, since the desiccant is made of a moisture-absorbing material that chemically absorbs moisture, the absorbed moisture is not released even if the storage chamber is heated to a high temperature by turning on the bulb, so that dew condensation on the inner surface of the lens can be prevented. Also, at low temperatures, the closed storage chamber does not suck in the outside air, so that it is not necessary to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0019]
Still further, the present invention provides an automotive headlamp in which a bulb and a reflector are accommodated in an accommodation room defined by a housing and a lens connected to a front opening of the housing. The housing and the lens, and a pressure adjusting means for absorbing a change in the pressure in the housing chamber. The housing chamber is made of a hygroscopic material which does not have a regenerating ability due to chemical absorption. A sixth feature is that a moisture absorbent is arranged.
[0020]
According to the sixth aspect, deformation of each part of the headlight is avoided by the pressure adjusting operation of the pressure adjusting means on the storage chamber and the moisture absorbing action of the moisture absorbent, and clouding due to condensation on the inner surface of the lens is prevented. Can be more effectively prevented. In addition, since the desiccant is made of a moisture absorbing material that does not have a regenerating ability by absorbing moisture chemically, even if the accommodation chamber becomes high temperature by turning on the bulb, the absorbed moisture is not released and the inner surface of the lens is regenerated. Dew condensation can be prevented, and since the enclosed chamber does not inhale outside air, there is no need to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0021]
Still further, according to the present invention, in addition to the fifth or sixth feature, a seventh feature is that the desiccant is mounted on a holder detachably attached to the housing.
[0022]
According to this seventh feature, the moisture absorbent can be easily replaced by pulling out the holder from the housing. Therefore, for example, by replacing the moisture absorbent at the time of valve replacement or legal inspection of the vehicle, The function of the hygroscopic agent is always exerted to keep the accommodation room at low humidity, and it is possible to reliably prevent the occurrence of fogging due to condensation on the inner surface of the lens.
[0023]
Still further, according to the present invention, in addition to any one of the fifth to seventh features, the desiccant is placed outside an optical path until light emitted from the bulb is reflected by the reflector and emitted from the lens. The arrangement is an eighth feature.
[0024]
According to the eighth feature, most of the light emitted from the bulb is emitted through the lens without any interference by the moisture absorbent, and the emitted light from the bulb can be effectively used without waste. Also, the design of the headlight requires only the same design time as that of the conventional optical design such as the light distribution characteristics, and does not require extra design man-hours, thereby shortening the design time.
[0025]
According to a ninth feature of the present invention, in addition to any one of the fifth to eighth features, the desiccant is made of a moisture-absorbing material containing at least one of magnesium oxide and magnesium chloride as a main component. I do.
[0026]
According to the ninth feature, the hygroscopic agent has extremely high hygroscopic performance as compared with a hygroscopic agent made of silica gel, and can prevent fogging of the lens inner surface even with a small amount, so that the installation space is small. It can contribute to making the headlights more compact.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.
[0028]
FIG. 1 is a front view of a vehicle headlamp according to a first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is an exploded perspective view of the agent holder, FIG. 4 shows a second embodiment of the present invention, corresponding to FIG. 2, and FIG. 5 shows a third embodiment of the present invention, corresponding to FIG. 2, FIG. FIG. 7 shows a fourth embodiment of the present invention, corresponding to FIG. 2, and FIG. 7 is a diagram comparing the hygroscopic performance of the hygroscopic agent of the present invention with a conventional hygroscopic agent (silica gel).
[0029]
First, a description will be given of the first embodiment of the present invention shown in FIGS.
[0030]
In FIGS. 1 and 2, reference numeral 1 denotes a left headlight of a vehicle, and a right headlight has a symmetrical configuration, and thus is omitted from the drawings. The housing 2 of the headlamp 1 has a bowl shape with an open front surface, and a lens 3 is connected to the open end of the front surface via a seal member 4. The housing 2 and the lens 3 define a horizontally long storage chamber 5 which is hermetically sealed. The storage chamber 5 has a high beam valve 6H, a low beam valve 6L, a turn signal valve 6T, and valves 6H, 6L, The reflectors 7H, 7L, 7T surrounding the 6T and the integral partition hood 8 for partitioning between the front openings of the reflectors 7H, 7L, 7T are accommodated. The partition hood 8 is located between the housing 2 and the lens 3. Be pinched.
[0031]
Each of the reflectors 7H, 7L, 7T is supported by a housing 2 via a support arm (not shown) with a gap 9 therebetween, and a gap 10 between the reflectors 7H, 7L, 7T and the partition hood 8. Is provided. Thus, the first and second reflectors 7H, 7L, 7T and the partition hood 8 allow the housing chamber 5 to have the first valve chamber 12H for housing the high beam valve 6H, the second valve chamber 12L for housing the low beam valve 6L, and the turn signal valve 6T. Is divided into three chambers 12T, 12H, 12L, and 12T. The three chambers 12H, 12L, and 12T communicate with each other via a gap 10 between each of the reflectors 7H, 7L, and 7T and the partition hood 8, and also have a housing. 2 and each of the reflectors 7H, 7L, 7T.
[0032]
On the rear wall of the reflectors 7H, 7L, 7T, valve insertion ports 13H, 13L, 13T are opened corresponding to the valves 6H, 6L, 6T, and the valve insertion ports 13H, 13L, 13T are provided with valves 6H, 6L. , 6T, respectively, are removably attached to sockets 14H, 14L, 14T. Cap mounting holes 15H, 15L, and 15T are opened in the rear wall of the housing 2 corresponding to the sockets 14H, 14L, and 14T, respectively, and the sockets 14H, 14L, and 14T are provided in the cap mounting holes 15H, 15L, and 15T. The caps 16H, 16L, and 16T holding the are fitted.
[0033]
The housing 2 is provided with a pressure adjusting means 20 for absorbing a pressure change in the storage chamber 5 at an appropriate position on the back side of the reflectors 7H, 7L, 7T. The pressure adjusting means 20 includes a diaphragm 22 for closing the opening 21 provided at an appropriate position of the housing 2 on the back side of the reflectors 7H, 7L, 7T so as to expose the inner side surface to the housing chamber 5. A cover 23 that covers the outer surface of the diaphragm 22 is fixed together with the diaphragm 22 with screws 28, and a vent hole 24 that communicates the outer surface of the diaphragm 22 with the atmosphere is formed in the cover 23.
[0034]
In the accommodation room 5, a moisture absorbent 25 for absorbing moisture in the accommodation room 5 is disposed at an appropriate position on the back side of the reflectors 7H, 7L, 7T. The desiccant 25 is held in a desiccant holder 26 that is bayonet-coupled to an opening 35 provided at an appropriate position in the housing 2 via a seal member 29. That is, as shown in FIG. 3, the desiccant holder 26 has a pair of holding arms 26a, 26a inserted into the storage chamber 5, and the saw-toothed slip stoppers 27, 27 of these holding arms 26a, 26a. The hygroscopic agent 25 is sandwiched between the opposing surfaces respectively formed with.
[0035]
The hygroscopic agent 25 is made of a hygroscopic material that does not have a regenerating ability by absorbing moisture chemically and is hardly deliquescent. Specifically, the hygroscopic agent 25 is made of a hygroscopic material containing at least one of magnesium oxide and magnesium chloride as a main component, and desirably contains magnesium oxide and magnesium chloride as main components, and the mixing ratio is 50% by weight. It is composed of a 50-70: 30 hygroscopic material.
[0036]
With the above configuration, the pressure adjusting means 20 and the hygroscopic agent 25 are disposed outside the optical path until the light radiated from the valves 6H, 6L is reflected by the reflectors 7H, 7L and emitted from the lens 3. Is done.
[0037]
Next, the operation of the first embodiment will be described.
[0038]
Since the low beam bulb 6L or the high beam bulb 6H emits considerably high heat when it is turned on, the accommodation room 5 becomes hot and raises the pressure, and when it is turned off, the pressure drops due to the dissipation of the heat. When the pressure rises, the diaphragm 22 bends toward the cover 23, thereby expanding the effective volume of the storage chamber 5 to absorb the rise in pressure. When the pressure drops, the diaphragm 22 bends toward the storage chamber 5 side. As a result, the effective volume of the storage chamber 5 is reduced, and the above pressure drop is absorbed. Therefore, regardless of the severe temperature change of the storage room 5, the storage room 5 is always kept at a substantially constant pressure without breathing the outside air. Since it can be avoided and the storage room 5 does not inhale high humidity outside air, it is possible to prevent clouding due to condensation on the inner surface of the lens 3. Of course, since the closed accommodation chamber 5 does not inhale outside air, it is not necessary to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0039]
In addition, since the diaphragm 22 is attached to the housing 2 on the back side of the reflectors 7H, 7L, 7T, the dead space between the housing 2 and the reflectors 7H, 7L, 7T is effectively used for installing the diaphragm 22, and the headlight is used. Since the size of the lamp 1 can be avoided and the diaphragm 22 can be hidden by the reflectors 7H, 7L, 7T, the external appearance can be kept good without being seen from the outside through the lens 3.
[0040]
When wet outside air flows into the storage room 5 due to replacement of the low beam valve 6L and other valves, and the humidity of the storage room 5 increases, the moisture absorbent 25 disposed in the storage room 5 is removed from the inside of the storage room 5. Therefore, the occurrence of fogging due to dew condensation on the inner surface of the lens 3 can be prevented. Since the desiccant 25 is held by the desiccant holder 26 detachably mounted on the housing 2, the desiccant 25 can be easily replaced by pulling the desiccant holder 26 out of the housing 2. For example, when the valves 6H, 6L, 6T are replaced, or when the legal inspection of the vehicle is performed, the function of the moisture absorbent 25 is always performed, so that the function of the moisture absorbent 25 is always maintained, and the housing chamber 5 is kept at a low humidity. Clouding due to dew condensation can be reliably prevented.
[0041]
The first, second, and third valve chambers 12H, 12L, and 12T in which the high-beam valve 6H, the low-beam valve 6L, and the turn signal valve 6T are disposed communicate with each other, and are connected to the reflectors 7H, 7L, and 7T. Since it is also in communication with the space between the housing 2 and the first, second, and third valve chambers 12H, 12L, and 12T, a single pressure adjusting means 20 and a desiccant 25 can be commonly used. The structure can be simplified.
[0042]
In particular, since the pressure adjusting means 20 and the moisture absorbing agent 25 are provided together, the deformation of each part of the headlight 1 is avoided by the pressure adjusting action of the pressure adjusting means on the storage chamber 5 and the moisture absorbing action of the moisture absorbing agent 25. This is extremely effective in preventing fogging due to dew condensation on the inner surface of the lens 3 more effectively.
[0043]
FIG. 7 is a graph showing the relationship between the moisture absorption when the moisture absorbent 25 of the present invention is composed of a moisture absorbing material containing magnesium oxide and magnesium chloride in a weight ratio of 60 to 40, and the moisture absorption of a conventional moisture absorbent made of silica gel. The result of having performed the comparative test based on the test method of JISZ0701 is shown.
[0044]
As is clear from the figure, under four environments of 5 ° C / 35% RH (humidity), 25 ° C / 20% RH, 25 ° C / 50% RH, and 25 ° C / 90% RH, It has been confirmed that the moisture absorbent 25 of the present invention has a moisture absorption of about 2 to 4 times that of the conventional moisture absorbent. Although not shown, it was also confirmed that the composition had a moisture absorption of about 14 times in an environment of 60 ° C./95% RH.
[0045]
As described above, the extremely high moisture absorption of the moisture absorbent 25 of the present invention means that the fogging of the inner surface of the lens 3 can be prevented even with a small amount of the moisture absorbent 25. It can contribute to downsizing. In addition, since the desiccant 25 does not have a regenerating ability, it is possible to prevent the dew condensation due to a temperature change in the closed accommodation room 5.
[0046]
The pressure adjusting means 20 and the desiccant 25 are disposed outside the optical path from the light emitted from the valves 6H and 6L to the light reflected from the reflectors 7H and 7L and emitted from the lens 3, so that the valves 6H and 6L are disposed. Most of the light emitted from 6L is emitted through the lens 3 without any interference by the moisture absorbent, so that the emitted light from the valves 6H and 6L can be effectively used without waste. In addition, the design of the headlight requires only the same design time as the conventional optical design such as the light distribution characteristics, and does not require extra design man-hours. In addition, since there is no need to consider the breathing of the storage chamber 5 as disclosed in Patent Document 2, the degree of freedom of design is not hindered, and the design cost can be reduced in conjunction with the shortening of the design time. Can be planned.
[0047]
Some hygroscopic materials that can chemically absorb moisture show deliquescent, but the hygroscopic agent 25 of the present invention is a natural type hygroscopic material mainly composed of magnesium oxide and magnesium chloride, which hardly exhibits deliquescent. , It is a natural material that is difficult to deliquesce, and can have a small effect on the environment even when treated as waste.
[0048]
Next, a second embodiment of the present invention shown in FIG. 4 will be described.
[0049]
In the second embodiment, the pressure adjusting means 20 is installed in a place separated from the headlight 1, for example, in an engine room. The pressure adjusting means 20 in this case is composed of a casing 30 and a diaphragm 22 attached to the inner peripheral wall of the casing 30 and partitioning the inside thereof into a pressure regulating chamber 31 and an atmosphere chamber 32. Is connected to the accommodation room 5 of the headlight 1 via a flexible conduit 33, and the atmosphere chamber 32 is opened to the atmosphere via a ventilation hole 34 of the casing 30. Other configurations are the same as those of the previous embodiment. Therefore, in FIG. 4, portions corresponding to those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0050]
According to the second embodiment, since the pressure adjusting means 20 can be freely installed at an appropriate place separated from the headlight 1, the versatility is high.
[0051]
Next, a third embodiment of the present invention shown in FIG. 5 will be described.
[0052]
In the fifth embodiment, a mounting hole 40 is provided on the rear surface of the housing 2 so as to avoid the cap mounting holes 15H, 15L, 15T, and the mounting hole 40 has a bottomed cylindrical shape in which a moisture absorbent 25 is provided on the inner surface. Is attached detachably.
[0053]
The other configuration is the same as that of the first embodiment. Therefore, in FIG. 5, portions corresponding to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0054]
According to the third embodiment, the relatively large back surface of the housing 2 can be used to mount the relatively large moisture absorbing agent holding cap 41. Therefore, the amount of the moisture absorbing agent 25 held by the cap 41 can be greatly increased. Can be adjusted.
[0055]
Finally, a fourth embodiment of the present invention shown in FIG. 6 will be described.
[0056]
In the fourth embodiment, the pressure adjusting means 20 is slidably fitted into a cylinder 42 via a seal member 44, and the interior thereof is divided into a pressure regulating chamber 31 and an atmosphere chamber 32. The pressure regulating chamber 31 is communicated with the housing chamber 5 of the headlight 1 via a flexible conduit 33, and the atmosphere chamber 32 is opened to the atmosphere from the end face of the cylinder 42. The piston 43 includes a piston rod 43a that is operated when the piston 43 is inserted and removed.
[0057]
When the headlamp 1 is mounted on an automobile, the desiccant 25 is adhered to a position invisible from the outside, for example, to the back surface of the partition hood 8. Therefore, the desiccant 25 must be adhered to the back surface of the partition hood 8 immediately before the lens 3 is attached to the housing 2 in the assembly process of the headlight 1.
[0058]
The other configuration is the same as that of the first embodiment. Therefore, in FIG. 6, parts corresponding to those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. In the example, at the initial stage of use of the headlight 1, the housing 2 may not be provided with the moisture absorbent holder 26, but may be simply provided with a sealing stopper at the opening 35 for mounting the moisture absorbent holder 26. Even if it is attached, it is not necessary to hold the desiccant 25 in the holder 26 from the beginning.
[0059]
According to the fourth embodiment, when the pressure changes due to the temperature change of the storage chamber 5 due to the turning on and off of the valves 6L and 6H, the piston 43 advances and retreats in the cylinder 42, and the volume of the pressure regulating chamber 31 is changed. , The pressure fluctuation in the storage chamber 5 can be absorbed, and deformation of each part of the headlight 1 can be avoided. As described above, the pressure adjusting means 20 including the cylinder 42 and the piston 43 has a small number of parts and has a simple structure, so that it can be provided at a low cost.
[0060]
Further, in the assembling process of the headlamp 1, the hygroscopic agent 25 is adhered to the back surface of the partition hood 8 immediately before attaching the lens 3 to the housing 2, so that a small space between the partition hood 8 and the lens 3 is used. Accordingly, the moisture absorbent 25 can be installed, and the moisture absorbent 25 is disposed close to the lens 3, so that dew condensation on the inner surface of the lens 3 can be effectively prevented.
[0061]
The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention. For example, when the first, second, and third valve chambers 12H, 12L, and 12T are individually sealed, the pressure adjusting means 20 can be individually connected to each of the valve chambers 12H, 12L, and 12T. Alternatively, a common pressure adjusting means 20 can be provided at the boundary between the valve chambers 12H, 12L, and 12T. In addition, the turn signal bulb 6T can be omitted from the headlight 1. The present invention is also applicable to a headlight in which the high beam bulb 6H and the low beam bulb 6L are configured as a single type.
[0062]
Further, in each of the above embodiments, the fogging due to the dew condensation on the inner surface of the lens 3 is prevented by both the pressure adjusting means 20 and the hygroscopic agent 25. Clouding due to condensation can also be prevented. When only the hygroscopic agent 25 is provided, the excessive pressure is released when the temperature of the storage chamber 5 is high, and the intake valve is prevented from being sucked when the temperature is low. It is effective in achieving compatibility with anti-fog.
[0063]
【The invention's effect】
As described above, according to the first aspect of the present invention, a vehicle front housing a valve and a reflector in a housing chamber defined by a housing and a lens connected to a front opening of the housing. In the illumination lamp, the housing and the lens are configured so as to hermetically seal the accommodation chamber, and pressure adjusting means for absorbing a pressure change in the accommodation chamber is provided. Even if the temperature changes drastically and the accompanying change in the pressure in the storage chamber, the pressure adjustment means absorbs the change, so that the storage chamber always maintains a substantially constant pressure without breathing outside air. Therefore, it is possible to prevent each part of the headlight from being deformed, and to prevent the outside air from being sucked into the housing chamber, thereby preventing the formation of clouding due to dew condensation on the inner surface of the lens. In addition, since the closed accommodation chamber does not inhale the outside air, it is not necessary to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0064]
According to the second aspect of the present invention, in addition to the first aspect, the pressure adjusting means includes a diaphragm having one side surface facing the accommodation room and the other side facing the atmosphere. The vigorous pressure change can be accurately absorbed by the deformation of the diaphragm to prevent deformation of each part of the headlight, while effectively preventing fogging due to dew condensation on the inner surface of the lens.
[0065]
According to the third aspect of the present invention, in addition to the second aspect, since the diaphragm is attached to the housing on the back side of the reflector, the dead space between the housing and the reflector can be effectively used for installing the diaphragm. By using this, it is possible to avoid an increase in the size of the headlight, and since the diaphragm can be hidden by the reflector, the appearance can be kept good without being seen from the outside through the lens.
[0066]
According to a fourth aspect of the present invention, in addition to the second aspect, the pressure adjusting means communicates with a casing installed outside the housing through the casing to the storage chamber via a conduit. Pressure adjustment chamber and a diaphragm that separates the atmosphere chamber from the atmosphere, the pressure adjustment means can be freely installed in a suitable place away from the headlights, and is highly versatile. .
[0067]
According to a fifth aspect of the present invention, a headlamp for a vehicle, comprising a valve and a reflector housed in a housing defined by a housing and a lens connected to a front opening of the housing. In the above, the housing and the lens are configured so as to hermetically seal the storage chamber at least at a low temperature, and a hygroscopic agent formed of a hygroscopic material that does not have a reproducibility due to chemical absorption is disposed in the storage chamber. Therefore, when wet outside air flows into the storage room due to valve replacement or the like, and the humidity in the storage room rises, the moisture absorbent absorbs the moisture in the storage room, thereby preventing fogging due to condensation on the inner surface of the lens. Can be prevented. Moreover, since the desiccant is made of a moisture-absorbing material that chemically absorbs moisture, the absorbed moisture is not released even if the storage chamber is heated to a high temperature by turning on the bulb, so that dew condensation on the inner surface of the lens can be prevented. Also, at low temperatures, the closed storage chamber does not suck in the outside air, so that it is not necessary to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0068]
According to a sixth aspect of the present invention, there is provided an automotive headlamp comprising a bulb and a reflector housed in a chamber defined by a housing and a lens connected to a front opening of the housing. In the above, the housing and the lens are configured so as to hermetically seal the accommodation chamber, and pressure adjusting means for absorbing a pressure change in the accommodation chamber is provided. Since a moisture absorbent made of a non-absorbent material is placed, deformation of each part of the headlight is avoided by the pressure regulating action of the pressure regulating means on the storage chamber and the moisture absorbing action of the moisture absorbent. The generation of fogging due to dew condensation can be more effectively prevented. In addition, since the desiccant is made of a moisture absorbing material that does not have a regenerating ability by absorbing moisture chemically, even if the accommodation chamber becomes high temperature by turning on the bulb, the absorbed moisture is not released and the inner surface of the lens is regenerated. Dew condensation can be prevented, and since the enclosed chamber does not inhale outside air, there is no need to specially enhance the function of the moisture absorbent, and it is possible to prevent dust from entering.
[0069]
According to the seventh aspect of the present invention, in addition to the fifth or sixth aspect, the desiccant is mounted on a holder detachably mounted on the housing, so that the holder is pulled out of the housing. Therefore, the moisture absorbent can be easily replaced, so that, for example, when the valve is replaced or when the vehicle is subjected to legal inspection, the function of the moisture absorbent is always exerted to keep the accommodation room at a low humidity. , Fogging due to condensation on the inner surface of the lens can be reliably prevented.
[0070]
According to an eighth aspect of the present invention, in addition to any one of the fifth to seventh aspects, the light absorbent irradiates the light emitted from the bulb with the light reflected by the reflector and emitted from the lens. The light emitted from the bulb is not interfered by the hygroscopic agent at all, most of the light is emitted through the lens, and the emitted light from the bulb can be used effectively without waste. . Also, the design of the headlight requires only the same design time as that of the conventional optical design such as the light distribution characteristics, and does not require extra design man-hours, thereby shortening the design time.
[0071]
According to a ninth aspect of the present invention, in addition to any one of the fifth to eighth aspects, the desiccant is made of a moisture-absorbing material containing at least one of magnesium oxide and magnesium chloride as a main component. Therefore, the hygroscopic agent has an extremely high hygroscopic performance as compared with a hygroscopic agent made of silica gel, and can prevent the fogging of the lens inner surface even with a small amount, so that the installation space is small and the headlight is compact. Can contribute to
[Brief description of the drawings]
FIG. 1 is a front view of an automotive headlamp according to a first embodiment of the present invention.
FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1;
FIG. 3 is an exploded perspective view of a moisture absorbent and a moisture absorbent holder attached to the headlight.
FIG. 4 is a diagram showing a second embodiment of the present invention and corresponding to FIG. 2;
FIG. 5 is a view showing a third embodiment of the present invention and corresponding to FIG. 2;
FIG. 6 is a view showing a fourth embodiment of the present invention and corresponding to FIG. 2;
FIG. 7 is a comparison diagram of the moisture absorption performance of the moisture absorbent of the present invention and a conventional moisture absorbent (silica gel).
[Explanation of symbols]
1 ... Headlight
2. Housing
3 ... Lens
5 .... accommodation room
6H ···· Valve (High beam valve)
6L ··· Valve (valve for low beam)
7H · · · reflector (high beam reflector)
6L ····· Reflector (low beam reflector)
20 ... Pressure adjusting means
22 ... Diaphragm
25 ... Hygroscopic agent
26 Holder
30 ... Casing
31 ... Pressure regulating chamber
32 ... Atmosphere chamber
33 ··· Conduit

Claims

ハウジング（２）と，このハウジング（２）の前面開口部に結合されるレンズ（３）とで画成される収容室（５）に，バルブ（６Ｈ，６Ｌ）及びリフレクタ（７Ｈ，７Ｌ）を収容してなる自動車用前照灯において，
前記収容室（５）を密閉するように前記ハウジング（２）及びレンズ（３）を構成すると共に，前記収容室（５）の圧力変化を吸収する圧力調整手段（２０）を設けたことを特徴とする，自動車用前照灯の曇り止め装置。A valve (6H, 6L) and a reflector (7H, 7L) are provided in a storage chamber (5) defined by a housing (2) and a lens (3) coupled to a front opening of the housing (2). In the housed automotive headlight,
The housing (2) and the lens (3) are configured to hermetically seal the accommodation chamber (5), and a pressure adjusting means (20) for absorbing a pressure change in the accommodation chamber (5) is provided. Anti-fog device for automotive headlamps.

請求項１記載の自動車用前照灯の曇り止め装置において，
前記圧力調整手段（２０）が，一側面を前記収容室（５）に，他側面を大気にそれぞれ臨ませたダイヤフラム（２２）を備えることを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to claim 1,
The fogging prevention device for a headlight for an automobile, characterized in that the pressure adjusting means (20) includes a diaphragm (22) having one side face in the housing chamber (5) and the other side face to the atmosphere. .

請求項２記載の自動車用前照灯の曇り止め装置において，
前記リフレクタ（７Ｈ，７Ｌ）の裏側で前記ハウジング（２）に前記ダイヤフラム（２２）を取り付けたことを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to claim 2,
An anti-fog device for an automotive headlamp, wherein the diaphragm (22) is attached to the housing (2) behind the reflectors (7H, 7L).

請求項２記載の自動車用前照灯の曇り止め装置において，
前記圧力調整手段（２０）を，前記ハウジング（２）外に設置されるケーシング（３０）と，このケーシング（３０）内を前記収容室（５）に導管（３３）を介して連通する調圧室（３１）と，大気に連通する大気室（３２）との区画するダイヤフラム（２２）とで構成したことを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to claim 2,
A pressure regulating means for connecting the pressure adjusting means (20) to a casing (30) installed outside the housing (2) and a casing (30) through the conduit (33) to the housing chamber (5); An anti-fog device for a headlight for an automobile, comprising a chamber (31) and a diaphragm (22) defining an atmosphere chamber (32) communicating with the atmosphere.

ハウジング（２）と，このハウジング（２）の前面開口部に結合されるレンズ（３）とで画成される収容室（５）に，バルブ（６Ｈ，６Ｌ）及びリフレクタ（７Ｈ，７Ｌ）を収容してなる自動車用前照灯において，
前記収容室（５）を，少なくともその低温時に密閉するように前記ハウジング（２）及びレンズ（３）を構成すると共に，この収容室（５）に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤（２５）を配置したことを特徴とする，自動車用前照灯の曇り止め装置。A valve (6H, 6L) and a reflector (7H, 7L) are provided in a storage chamber (5) defined by a housing (2) and a lens (3) coupled to a front opening of the housing (2). In the housed automotive headlight,
The housing (2) and the lens (3) are configured so as to hermetically seal the storage chamber (5) at least at a low temperature, and the storage chamber (5) chemically absorbs moisture and has no reproducibility. An anti-fog device for an automotive headlamp, comprising a moisture absorbent (25) made of a moisture absorbent material.

ハウジング（２）と，このハウジング（２）の前面開口部に結合されるレンズ（３）とで画成される収容室（５）に，バルブ（６Ｈ，６Ｌ）及びリフレクタ（７Ｈ，７Ｌ）を収容してなる自動車用前照灯において，
前記収容室（５）を密閉するように前記ハウジング（２）及びレンズ（３）を構成すると共に，前記収容室（５）の圧力変化を吸収する圧力調整手段（２０）を設け，さらに前記収容室（５）に，化学的に吸湿して再生能を持たない吸湿材料で構成された吸湿剤（２５）を配置したことを特徴とする，自動車用前照灯の曇り止め装置。A valve (6H, 6L) and a reflector (7H, 7L) are provided in a storage chamber (5) defined by a housing (2) and a lens (3) coupled to a front opening of the housing (2). In the housed automotive headlight,
The housing (2) and the lens (3) are configured to hermetically seal the housing chamber (5), and a pressure adjusting means (20) for absorbing a pressure change in the housing chamber (5) is provided. An anti-fog device for an automotive headlamp, characterized in that a moisture absorbent (25) made of a moisture-absorbing material which does not have a regenerative ability by absorbing moisture chemically is disposed in the chamber (5).

請求項５又は６記載の自動車用前照灯の曇り止め装置において，
前記吸湿剤（２５）を，前記ハウジング（２）に着脱可能に取り付けられるホルダ（２６）に装着したことを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to claim 5 or 6,
An anti-fog device for a headlight for an automobile, characterized in that the desiccant (25) is mounted on a holder (26) detachably mounted on the housing (2).

請求項５〜７の何れかに記載の自動車用前照灯の曇り止め装置において，
前記吸湿剤（２５）を，前記バルブ（６Ｈ，６Ｌ）から放射された光が前記リフレクタ（７Ｈ，７Ｌ）で反射されて前記レンズ（３）から出射されるまでの光路外に配置したことを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to any one of claims 5 to 7,
Wherein the moisture absorbent (25) is arranged outside the optical path until the light emitted from the bulb (6H, 6L) is reflected by the reflector (7H, 7L) and emitted from the lens (3). Characteristic, anti-fog device for automotive headlamps.

請求項５〜８の何れかに記載の自動車用前照灯の曇り止め装置において，
前記吸湿剤（２５）を，酸化マグネシウム及び塩化マグネシウムの少なくとも一方を主成分とする吸湿材料で構成したことを特徴とする，自動車用前照灯の曇り止め装置。An anti-fog device for an automotive headlamp according to any one of claims 5 to 8,
An anti-fog device for an automotive headlamp, wherein the moisture absorbent (25) is made of a moisture absorbent material containing at least one of magnesium oxide and magnesium chloride as a main component.