JP4608060B2

JP4608060B2 - Golf club head

Info

Publication number: JP4608060B2
Application number: JP2000250018A
Authority: JP
Inventors: 眞徳藪
Original assignee: Ｓｒｉスポーツ株式会社
Priority date: 2000-08-21
Filing date: 2000-08-21
Publication date: 2011-01-05
Anticipated expiration: 2020-08-21
Also published as: JP2002058762A

Description

【０００１】
【発明の属する技術分野】
本発明は、フェース部材とヘッド本体との溶接部の強度を高めうるゴルフクラブヘッドに関する。
【０００２】
【従来の技術及び発明が解決しようとする課題】
従来、例えば図７（Ａ）及びそのＹ−Ｙ線部分断面図である図７（Ｂ）に示す如く、板状のフェース部材ｂと、前面に前記フェース部材ｂが閉じる開口部ｄを有しかつクラウン部ｅとソール部ｆとサイド部ｇとを形成したヘッド本体ｃとを溶接により接合したウッド型のゴルフクラブヘッドａ１が知られている。このヘッドａ１では、ボール打撃時の衝撃力に耐え得るよう、ヘッド本体ｃにフェース部材ｂの裏面の周縁部を支えるバックアップ部ｈが形成されている。またフェース部材ｂは、前記開口部ｄの周縁と溶接される。また溶接箇所となる開口部ｄの周縁の厚さは、溶接による強度の不均一性を見込み、予めそれを見込んで厚さＡを大に設定される。
【０００３】
ところが、上述の様なヘッドａ１では、前記バックアップ部ｈや厚さＡが大の開口部ｄの周縁などによりフェース部材ｂの撓み領域が減じられ、ひいては反発特性が十分に発揮されず打球の飛距離が低下したり、特にヘッド体積を大型化した場合にはヘッド重量が増加し易い等の問題がある。そこで、例えば図８（Ａ）、（Ｂ）に示すように、フェース部材ｋに、ヘッドの後方に向かって小巾でのびる延長部ｎを形成し、溶接部ｊをクラウン部ｅ、サイド部ｆ、ソール部ｇにて行うようにしたヘッドａ２も考えられる。
【０００４】
しかしながら、近年の大型ヘッドでは、特にクラウン部ｅやサイド部ｆの厚さｔ２が、フェース部材ｋの厚さｔ１に対して３０〜５０％程度に形成されている。従って、このように厚さが異なる２つの部材、例えば延長部ｎとクラウン部ｅとを向き合わせて溶接した場合、その厚さの違いによる熱容量の相違に基づき、熱容量が相対的に小さいクラウン部ｅ（ヘッド本体ｍ側）が先に熔け始め、熱容量が相対的に大きいフェース部材ｋ側が十分に熔け始める前に溶接ビードが両者の間に満たされてしまい、溶接部で強固な接合が得られず該溶接部での耐久性が低下するという問題がある。
【０００５】
本発明は、以上のような問題に鑑み案出なされたもので、フェース部材とヘッド本体とを溶接する各溶接部の厚さ、巾などを一定範囲に規制することを基本として、両溶接部の熱容量を近づけることにより溶接部の接合強度を向上しつつフェース部材の反発特性の低下をも防止しうるゴルフクラブヘッドを提供することを目的としている。
【０００６】
【課題を解決するための手段】
本発明のうち請求項１記載の発明は、フェース部の少なくとも一部を形成する板状のフェース部材、及び前面に前記フェース部材が閉じる開口部を有しかつ前記前面から後方にのびるクラウン部とソール部とサイド部とを形成したヘッド本体からなり、かつ前記フェース部材の裏面の周縁部と、該ヘッド本体の前記前面とを溶接により接合したゴルフクラブヘッドであって、前記ヘッド本体は、前記前面から後方に１〜４mmを隔てるまでの領域Ｗ１にヘッド内外方向の厚さＴａの厚肉部を形成し、かつフェース部材は、前記前面と当接する領域に前後方向の厚さＴｆの取付部を形成するとともに、前記厚肉部と前記取付部との厚さの比（Ｔｆ／Ｔａ）が０．６〜１．２であり、しかも前記ヘッド本体は、前記厚肉部の後方にヘッド内外方向の厚さＴｕが前記厚肉部の厚さＴａよりも小の薄肉部を具えるとともに、前記厚肉部と薄肉部とはステップ状に厚さが変化し、前記厚肉部の厚さＴａは、２．０〜４．０mmであり、かつ前記フェース部材の前記取付部の厚さＴｆが１．５〜３．５mmであり、しかも前記薄肉部は、ヘッド内外方向の厚さＴｕ１が１．２〜１．６mmの第１の薄肉部と、この第１の薄肉部の後方にステップ状に連なりかつ厚さＴｕ２が０．８〜１．２mmの第２の薄肉部とを含むことを特徴とする。
【０００８】
また前記第１の薄肉部は、前後方向の長さＷ２が３〜７mm、かつ前記第２の薄肉部は、前後方向の長さＷ３が３〜７mmとすることが望ましい。なお薄肉部は、前記第２の薄肉部の後方に厚さＴｕ３が０．７〜１．０mmかつ前記第２の薄肉部の厚さＴｕ２よりも小の第３の薄肉部を形成することができる。
【０００９】
また前記フェース部材及びヘッド本体は、比重が５．０以下の金属材料からなるとともにヘッド体積を３００cm³以上とすることが特に望ましい。
【００１０】
【発明の実施の形態】
以下本発明の実施の一形態を図面に基づき説明する。
図１は本実施形態としてウッド型のゴルフクラブヘッド（以下、単に「ヘッド」ということがある。）１の分解斜視図、図２は接合したヘッドのＡ−Ａ線端面図、図３は図２の部分拡大図をそれぞれ示している。図において、ヘッド１は、フェース部材２とヘッド本体３とから構成され、これらを溶接により接合して形成されている。また本実施形態のヘッド１は、例えばヘッド体積が３００cm³以上でありかつ内部を中空部ｉとした大型ヘッドとして形成されている。ヘッド体積はヘッドの外表面により囲む体積により定められ、シャフト取付部（ネック部）などを含むものとする。また中空部ｉは完全に中空とされる場合の他、発泡樹脂などが適宜充填されることもある。
【００１１】
前記フェース部材２は、ボールを打撃する部分であるフェース部４の少なくとも一部、本例では実質的にフェース部４の全体部分を形成する板状のものが例示される。このフェース部材２は、プレスフォーミング、鍛造、鋳造など種々の方法で形成することができ、本例では圧延材を主として曲げ加工するプレスフォーミングにより形成された塑性加工品からなるものを例示している。このような塑性加工品は、鋳造品に比して材料選択の幅が広がりかつ材料欠陥が少なく、加工が容易である点で好ましい。
【００１２】
またフェース部材２には、高い引張強度を有し、かつ低比重、とりわけ比重が５．０以下の金属材料を用いるのが好ましい。比重が５．０を超えると、大型ヘッドとしたときにヘッド重量の増大を招きやすくなるためである。より具体的には、フェース部材２には、チタンないしチタン合金を好適に用いうる。チタン合金には、汎用のＴｉ−６Ａｌ−４Ｖ等に加え、より高強度なチタン合金として、Ｔｉ−１５Ｖ−３Ｃｒ−３Ａｌ−３Ｓｎ、Ｔｉ−１０Ｖ−２Ｆｅ−３Ａｌ、Ｔｉ−１５Ｍｏ−５Ｚｒ−３Ａｌ、Ｔｉ−１３Ｖ−１１Ｃｒ−３Ａｌ、Ｔｉ−２２Ｖ−４Ａｌ（ＤＡＴ５１）、Ｔｉ−３Ａｌ−２．５Ｖ、Ｔｉ−４．５Ａｌ−３Ｖ−２Ｍｏ−２Ｆｅ（ＳＰ７００）、Ｔｉ−２０Ｖ−４Ａｌ−１Ｓｎ等を用いることができる。ただし、これらの金属材料には限定されない。
【００１３】
またフェース部材２は、本例ではその中央部、周縁部ともほぼ均一な厚さＴで形成された板状体からなるものを例示している。とりわけフェース部材２の中央部の厚さＴは、例えば１．５〜３．５mm、より好ましくは２．０〜２．８mmであるのが望ましい。前記厚さＴが１．５mm未満の場合、用いる材料にもよるがボール打撃時の衝撃により、該フェース部材２の割れや凹み等の損傷が生じやすい傾向があり、逆に３．５mmを超える場合、フェース部４の反発特性が低下し飛距離を損なう傾向がある。
【００１４】
また前記ヘッド本体３は、前面５（フェース部材２側を向く面）に前記フェース部材２が閉じる開口部６を有しかつ前記前面５から後方にのびるヘッド上面をなすクラウン部７と、ヘッド底面をなすソール部９と、ヘッド側面をなすサイド部１０とを具えるとともに、シャフトが装着されるシャフト取付部１１が例えばクラウン部７のヒール寄りに一体的に突出形成されている。このようなヘッド本体３は、好ましくはロストワックス精密鋳造により各部を一体で形成されている。ただし、該ヘッド本体３は、２以上の部材を用い、これらを溶接することにより形成することもできる。またヘッド本体３も、高強度、とりわけ比重が５．０以下の金属材料を用いるのが好ましく、チタンないしチタン合金（前述）を用いることが望ましい。なおヘッド本体３とフェース部材２とは同一材料であっても良く、また異なる材料でも良い。特に好ましくは、両部材にチタン合金を用いるのが望ましい。
【００１５】
前記ヘッド本体３は、図３に拡大して示す如く、前記前面５から後方に１〜４mmを隔てるまでの領域Ｗ１にヘッド内外方向の厚さＴａの厚肉部１２を形成している。この厚肉部１２の厚さＴａは、２．０〜４．０mm、より好ましくは２．５〜３．５mmとするのが望ましい。他方、前記フェース部材２は、このヘッド本体３の前面５と当接する領域に前後方向の厚さＴｆの取付部２ａを形成する。この取付部２ａの厚さＴｆは、本例ではフェース部材２の中央部の厚さＴと略等しく設定されており、１．５〜３．５mm、より好ましくは２．０〜２．８mmの範囲で定めるのが特に望ましい。なおフェース部材２は、この取付部２ａの厚さＴｆと前記中央部の厚さＴとを違えることもできる。
【００１６】
そして本実施形態のヘッド１は、前記厚肉部１２の厚さＴａと前記取付部２ａとの厚さＴｆの比（Ｔｆ／Ｔａ）を０．６〜１．２に限定したことを特徴事項の一つとしている。フェース部材２とヘッド本体３とは、図４（Ａ）に示すように、前記フェース部材２の裏面２Ｂ（ボールを打球する面とは反対側の面）の周縁部と、ヘッド本体３の前記前面５とを溶接により接合しヘッド１として形成される。従って、溶接箇所がフェース部４の外部となる。この際、上述のようにヘッド本体３の厚肉部１２とフェース部材２の取付部２ａとの各厚さの比（Ｔｆ／Ｔａ）を一定範囲に限定することにより、溶接箇所となる厚肉部１２と取付部２ａとの熱容量をほぼ近似させることができる。
【００１７】
すなわち、図４（Ｂ）に示すように、フェース部材２と、ヘッド本体３とを溶接する際には、両部材間に熱源から溶接入熱が与えられ、この溶接入熱はフェース部材２、ヘッド本体３へそれぞれ熱伝導する。この際、厚肉部１２の長さＷ１やフェース部材２の取付部２ａの厚さＴｆとヘッド本体３の厚肉部１２の厚さＴａとの比を前記の如く限定し互いの熱容量を揃えることで、厚肉部１２、取付部２ａの双方をほぼ同時に熔かし始め、かつ図４（Ｃ）の如く、両部材の溶融部分２０に跨って溶接ビード１６を満たすことができる。これによりフェース部材２とヘッド本体３との強固な溶接部が得られる。
【００１８】
ここで、前記比（Ｔｆ／Ｔａ）が０．５未満又は２よりも大の場合、フェース部材２とヘッド本体３との前記厚さＴｆ、Ｔａの差が大きくなり、溶接時の熱容量が大きく異なるため同時に均一な熔解が得られ難くひいては溶接部の強度が低下し易い。このような観点より、前記比（Ｔｆ／Ｔａ）を０．６〜１．２としている。
【００１９】
また前記厚肉部１２は、その領域のヘッド前後方向の長さＷ１が、１mm未満であると、前記熱容量を揃える効果が低下しがちとなり、逆に４mmを超えると、フェース部材２に対する熱容量が大きくなる他、フェース部４の有効撓み領域を減じるとともに、大型ヘッドとした場合にはヘッド重量の増加を招きやすい傾向がある。このような観点より、前記厚肉部１２が形成される領域の長さＷ１は、より好ましくは２〜４mm、さらに好ましくは２〜３mmとすることが望ましい。
【００２０】
上述のような厚肉部１２は、前記ヘッド本体３の前面５の少なくとも一部に形成されていれば良いが、より好ましくは厚肉部１２は前記前面５の開口部６に沿った長さが前記前面５の全長さの５０％以上、より好ましくは７０％以上、さらに好ましくは１００％（すなわち、クラウン部７、ソール部９及びサイド部１０の全周）で形成されることにより、さらに高い溶接部の接合強度が得られる。
【００２１】
また本実施形態のヘッド１は、フェース部材２とヘッド本体３との溶接に際して、例えば図４（Ａ）、（Ｂ）に示したように、前記フェース部材２の周縁部２ｅと、前記ヘッド本体３の前面５の外周縁との少なくとも一方に、溶接用のぬすみ部Ｘを形成したものを例示している。本例ではフェース部材２の前記裏面２Ｂの周縁部２ｅを面取り状に切り欠くことでぬすみ部Ｘを形成したものを例示するが、ヘッド本体３側に形成しても良く、また両部材に形成することもできる。このようなぬすみ部Ｘを設けることにより、溶接ビード１６を安定して両部材間に満たしていくことができ、溶接部の接合強度を高めるのに役立つ他、溶接作業時の施工性を能率化しうる点で好ましい。なお盛られた溶接ビード１６は、研磨工程によって他の部分と面一になるよう研磨仕上げされる。
【００２２】
また本実施形態の前記ヘッド本体３は、図３に示したように、前記厚肉部１２の後方にヘッド内外方向の厚さが前記厚肉部１２の厚さＴａよりも小の薄肉部１３を具える。本例の薄肉部１３は、例えばヘッド内外方向の厚さＴｕ１が１．２〜１．６mmの第１の薄肉部１４と、この第１の薄肉部１４の後方に連なりかつ厚さＴｕ２が０．８〜１．２mmの第２の薄肉部１５とを含んで構成される。前記第１の薄肉部１４は、前後方向の長さＷ２が３〜７mm、より好ましくは４〜６mmで形成することが望ましい。前記長さＷ２が３mm未満であると、厚肉部１２から第２の薄肉部１５までの間で厚さの変化を急激とする傾向があり、逆に７mmを超えるとヘッドの重量増加を招きやすく大型ヘッドには適さない傾向がある。
【００２３】
また本例では前記第２の薄肉部１５が前記クラウン部７、ソール部９及びサイド部１０の主要部分をそれぞれ形成しており、ヘッド重量の低減に役立たせている。なお第２の薄肉部１５は、必ずしも前記クラウン部７、ソール部９及びサイド部１０の全てを形成する必要はなく、少なくとも一の部分を形成していれば足りる。
【００２４】
このように、厚肉部１２のヘッド後方に第１、第２の薄肉部１４、１５を形成することにより、ヘッド本体３の厚さがヘッド後方に向かって徐々に減じられるため、ヘッド本体３の急激な厚さの変化を防止しうる。これは剛性段差を減じ応力集中などを効果的に抑制し、かつヘッド重量の過度の増大を招くことなく耐久性を向上するのに役立つ。なお本例では、厚肉部１２、薄肉部１３は、ステップ状に厚さが変化するものを例示したが、このような態様に限定されるものではない。例えば図５に示すように、厚肉部１２は略一定の前記厚さＴａとし、薄肉部１３については滑らかに厚さを減じながらヘッドの後方にのびる如く形成することもできる。
【００２５】
図６には本発明の他の実施形態を示している。
本実施形態では、ヘッド本体３は、厚肉部１２の後方に、薄肉部１３として、第１の薄肉部１４、第２の薄肉部１５及び第３の薄肉部１６を順次具えたものが例示される。この場合、第１の薄肉部１４は、ヘッド内外方向の厚さＴｕ１が１．２〜１．６mmかつ前後方向の長さＷ２が３〜７mm、またこの第１の薄肉部１４の後方に連なる第２の薄肉部１５の厚さＴｕ２は０．８〜１．２mm、より好ましくは１．０〜１．２mmかつ前後方向の長さＷ３が３〜７mmとし、さらに第３の薄肉部の厚さＴｕ３は０．７〜１．０mmとするのが望ましい。
【００２６】
この形態では、ヘッド１をより大型化し、またフェース部材２の周辺部をより相対的に厚くし、ヘッド１の中央部をより薄く形成することにより、ヘッド１の慣性モーメントの向上と強度の向上とを両立している。また前記厚肉部１２の厚さＴａ、長さＷ１、前記薄肉部１３の厚さＴｕ１、Ｔｕ２又はＴｕ３、巾Ｗ２、Ｗ３、さらにはクラウン部７、ソール部９及びサイド部１０の各厚さなどは各位置において違えることにより、ヘッド１の重量配分設計を自在に行うことができる。
【００２７】
例えばソール部９に形成される厚肉部１２の厚さや長さを、クラウン部７側に形成される厚肉部１２のそれらよりも大とすることなどにより、ソール部９側により多くの重量を配することができる。この場合、ヘッド１の重心位置をより低くすることが可能になり、ひいてはボールが上がりやすいヘッド１を提供しうる。またサイド部１０のトウ側の厚肉部１２とヒール側の厚肉部１２とで厚さ、長さなどを違えることにより、ヘッドの重心位置をトウ側寄り又はヒール側寄りに設置することも可能になる。
【００２８】
【実施例】
表１に示す仕様によりヘッド体積が３２０cm³で実質的に同一外形を有するウッド型ゴルフクラブヘッドを試作するとともに、各ヘッドの反発係数、慣性モーメント、耐久性をテストした。
【００２９】
またフェース部の反発特性は、Ｕ．Ｓ．Ｇ．Ａ．の Procedure for Measureing the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999) に基づき行った。具体的にはゴフボールをボール発射装置を用いて発射し、台座上に固着することなく載置されたヘッドのフェース部のスイートスポットに衝突させ、ゴルフボールの衝突直前の入射速度Ｖｉと跳ね返り速度Ｖｏとを測定する。そして、ゴルフボールの入射速度をＶｉ、跳ね返り速度をＶｏ、ヘッド質量をＭ、ゴルフボールの平均質量をｍとした場合に、次式により反発係数ｅを算定した。
（Ｖｏ／Ｖｉ）＝（ｅＭ−ｍ）／（Ｍ＋ｍ）
なおゴルフボールの発射口からフェース部までの距離は５５インチとし、ボールがヘッドのスイートスポットの位置から５mm以上離れない位置でかつフェース面に対して直角に衝突させる。またゴルフボールはタイトリスト社製のピナクルゴールドを使用し、ボール初速は１６０フィート±０．５フィート（４８．７６８±０．１５２４ｍ／ｓ）に設定する。そして、比較例３の反発係数ｅを１００とする指数で評価した。数値が大きい程良好である。
【００３０】
また、ヘッドの慣性モーメントは、ヘッドを規定のライ角、ロフト角として水平面に載置した基準状態において、ヘッドの重心を通る垂直軸回り及び水平軸回りのそれぞれの慣性モーメントをINERTIA DYNAMICS Inc社製のMOMENT OF INERTIA MEASURING INSTRUMENTの MODEL NO.005-002を用いて測定した値である。この慣性モーメントが大きいほど、ミスショット時においてヘッドのぶれ量が少なくなり飛距離のロスを抑制しうる。
【００３１】
さらに、耐久性は、２ピースタイプのゴルフボールをエアーキャノン式発射機を用いて発射し、固定されたヘッドのフェース部に衝突させ、溶接箇所にひび割れ等の損傷が発生した個数を調べた（ｎ＝３０）。
テスト結果などを表１に示す。
【００３２】
【表１】

【００３３】
テストの結果、実施例のヘッドは、溶接部の耐久性を向上しており、またスイートスポット高さを低くかつ重心深度を大きく設計しうることが確認できた。また慣性モーメントも、比較例に比べて大きく設計しうることが確認できた。
【００３４】
【発明の効果】
上述したように、請求項１記載の発明では、ヘッド本体の厚肉部の長さや、その厚さＴａとフェース部材の取付部との厚さＴｆの比（Ｔｆ／Ｔａ）などを一定範囲に限定することにより、溶接箇所となる厚肉部と取付部との熱容量をほぼ近似させることができ、これにより、溶接時には厚肉部、取付部の双方をほぼ同時に熔かし始め、かつその上に溶接ビードを満たすことが可能となるため、フェース部材とヘッド本体との溶接部の接合強度を向上することができる。またフェース部材とヘッド本体との溶接が、フェース部材の裏面の周縁部と、ヘッド本体の前面とで行われるため、フェース部材の有効撓み領域を減じることが防止され、ヘッドの反発特性を向上しうる。
【００３５】
また、請求項２記載の発明のように、厚肉部の厚さＴａや前記フェース部材の取付部の厚さＴｆを一定の厚さに限定したときには、より確実に厚肉部と取付部との熱容量をほぼ近似させることができ、強固な溶接をなしうる。
【００３６】
また、請求項３記載の発明のように、ヘッド本体は、前記厚肉部の後方にヘッド内外方向の厚さが前記厚肉部の厚さよりも小の薄肉部を具えることにより、厚肉部によるヘッド重量の増大を抑制しヘッド重量の軽量化に役立つほか、ヘッドのフェース部材の周囲により多くの重量を配することで慣性モーメントを増大しうる。
【００３７】
また請求項４ないし６記載の発明のように、薄肉部は、ヘッド内外方向の厚さＴｕ１が１．２〜１．６mmの第１の薄肉部と、この第１の薄肉部の後方に連なりかつ厚さＴｕ２が０．８〜１．２mmの第２の薄肉部とを含むことにより、厚肉部からヘッド後方に厚さを徐々に減じることができる。これにより、急激な厚さの変化を防止してヘッドの耐久性を向上しうる。
【図面の簡単な説明】
【図１】本実施形態のヘッドの分解斜視図である。
【図２】そのＡ−Ａ線端面図である。
【図３】その部分拡大図である。
【図４】（Ａ）〜（Ｃ）は、フェース部材とヘッド本体との溶接を説明する拡大端面図である。
【図５】薄肉部の他の形態を示す拡大端面図である。
【図６】ヘッド本体の他の形態を示す拡大端面図である。
【図７】（Ａ）は従来のヘッドの分解斜視図、（Ｂ）はその部分断面図である。
【図８】（Ａ）は従来のヘッドの分解斜視図、（Ｂ）はその部分断面図である。
【符号の説明】
１ヘッド
２フェース部材
３ヘッド本体
４フェース部
５ヘッド本体の前面
６開口部
７クラウン部
９ソール部
１０サイド部
１２厚肉部
１３薄肉部
１４第１の薄肉部
１５第２の薄肉部
１６第３の薄肉部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a golf club head that can increase the strength of a welded portion between a face member and a head body.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, for example, as shown in FIG. 7 (A) and FIG. 7 (B) which is a partial sectional view taken along the line YY, a plate-like face member b and an opening d for closing the face member b on the front surface are provided. A wood-type golf club head a1 is known in which a head body c having a crown portion e, a sole portion f, and a side portion g is joined by welding. In the head a1, a back-up portion h that supports the peripheral edge of the back surface of the face member b is formed on the head body c so as to withstand the impact force at the time of hitting the ball. The face member b is welded to the periphery of the opening d. In addition, the thickness of the periphery of the opening d serving as a welded portion is set to a large thickness A in anticipation of strength non-uniformity due to welding.
[0003]
However, in the head a1 as described above, the bending region of the face member b is reduced by the backup portion h and the periphery of the opening portion d having a large thickness A, and as a result, the rebound characteristics are not sufficiently exhibited and the flying of the hit ball is reduced. When the distance is reduced or the head volume is increased, the head weight is likely to increase. Therefore, for example, as shown in FIGS. 8A and 8B, the face member k is formed with an extended portion n extending in a small width toward the rear of the head, the welded portion j being the crown portion e, and the side portion f. A head a2 which is performed at the sole part g is also conceivable.
[0004]
However, in recent large-sized heads, the thickness t2 of the crown part e and the side part f is formed to be about 30 to 50% with respect to the thickness t1 of the face member k. Therefore, when two members having different thicknesses, for example, the extension portion n and the crown portion e are welded face to face, the crown portion having a relatively small heat capacity is based on the difference in heat capacity due to the difference in thickness. e (head body m side) starts to melt first, and the face bead k side, which has a relatively large heat capacity, begins to melt sufficiently before the weld bead is filled between them, and a strong joint is obtained at the welded portion. Therefore, there is a problem that durability at the welded portion is lowered.
[0005]
The present invention has been devised in view of the above problems, and is based on restricting the thickness, width, etc. of each welded portion for welding the face member and the head body to a certain range. An object of the present invention is to provide a golf club head capable of improving the joint strength of the welded portion by reducing the heat capacity of the face member and preventing the rebound characteristics of the face member from being lowered.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is a plate-like face member that forms at least a part of the face portion, and a crown portion that has an opening for closing the face member on the front surface and extends rearward from the front surface. A golf club head comprising a head main body formed with a sole portion and a side portion, and having a peripheral edge on the back surface of the face member and the front surface of the head main body joined by welding, wherein the head main body is A thick portion having a thickness Ta in the head inward / outward direction is formed in a region W1 extending from the front to the rear by 1 to 4 mm, and the face member is attached to the region in contact with the front surface with a thickness Tf in the front-rear direction. And the thickness ratio (Tf / Ta) between the thick part and the attachment part is 0.6 to 1.2, and the head body is located behind and behind the thick part. Direction With the Tu is comprises a thin portion smaller than the thickness Ta of the thick portions, said thick thickness changes stepwise from the meat portion and the thin portion, the thickness Ta of the thick portions, The thickness Tf of the mounting portion of the face member is 1.5 to 3.5 mm, and the thin portion has a thickness Tu1 in the head inner / outer direction of 1.2. A first thin portion having a thickness of ˜1.6 mm, and a second thin portion having a thickness Tu2 of 0.8 to 1.2 mm connected to the rear of the first thin portion. To do.
[0008]
The first thin portion preferably has a length W2 in the front-rear direction of 3 to 7 mm, and the second thin portion preferably has a length W3 in the front-rear direction of 3 to 7 mm. The thin-walled portion may form a third thin-walled portion having a thickness Tu3 of 0.7 to 1.0 mm and smaller than the thickness Tu2 of the second thin-walled portion behind the second thin-walled portion. it can.
[0009]
The face member and the head body are particularly preferably made of a metal material having a specific gravity of 5.0 or less and a head volume of 300 cm ³ or more.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of a wood-type golf club head (hereinafter, simply referred to as “head”) 1 as an embodiment, FIG. 2 is an end view taken along the line AA of the joined head, and FIG. 2 respectively show partial enlarged views. In the figure, a head 1 is composed of a face member 2 and a head main body 3, and these are joined by welding. Further, the head 1 of the present embodiment is formed as a large-sized head having a head volume of 300 cm ³ or more and having a hollow portion i inside, for example. The head volume is determined by the volume surrounded by the outer surface of the head, and includes a shaft attachment portion (neck portion) and the like. Moreover, the hollow part i may be filled with a foamed resin or the like as appropriate in addition to the case where it is completely hollow.
[0011]
The face member 2 is exemplified by a plate-like member that forms at least a part of the face part 4 that hits a ball, in this example, substantially the whole part of the face part 4. The face member 2 can be formed by various methods such as press forming, forging, and casting. In this example, the face member 2 is made of a plastic processed product formed by press forming that mainly bends a rolled material. . Such a plastic processed product is preferable in that it has a wider range of material selection and fewer material defects than a cast product, and is easy to process.
[0012]
The face member 2 is preferably made of a metal material having a high tensile strength and a low specific gravity, particularly a specific gravity of 5.0 or less. This is because if the specific gravity exceeds 5.0, the head weight tends to increase when a large head is used. More specifically, titanium or a titanium alloy can be suitably used for the face member 2. In addition to general-purpose Ti-6Al-4V and the like, titanium alloys having higher strength include Ti-15V-3Cr-3Al-3Sn, Ti-10V-2Fe-3Al, Ti-15Mo-5Zr-3Al, Ti-13V-11Cr-3Al, Ti-22V-4Al (DAT51), Ti-3Al-2.5V, Ti-4.5Al-3V-2Mo-2Fe (SP700), Ti-20V-4Al-1Sn, etc. are used. be able to. However, it is not limited to these metal materials.
[0013]
Further, in this example, the face member 2 is exemplified by a plate-like body that is formed with a substantially uniform thickness T at both the central portion and the peripheral portion thereof. In particular, the thickness T of the central portion of the face member 2 is preferably 1.5 to 3.5 mm, more preferably 2.0 to 2.8 mm, for example. When the thickness T is less than 1.5 mm, depending on the material used, there is a tendency that damage such as cracks and dents of the face member 2 is likely to occur due to impact at the time of hitting the ball, and conversely exceeds 3.5 mm. In this case, the resilience characteristics of the face portion 4 tend to be deteriorated and the flight distance tends to be impaired.
[0014]
The head body 3 has an opening 6 that closes the face member 2 on the front surface 5 (a surface facing the face member 2 side) and a crown portion 7 that forms a top surface of the head extending rearward from the front surface 5 and a bottom surface of the head. A shaft attaching portion 11 to which a shaft is attached is integrally formed to protrude toward the heel of the crown portion 7, for example. Such a head body 3 is preferably formed integrally with each other by lost wax precision casting. However, the head body 3 can be formed by using two or more members and welding them. The head body 3 is also preferably made of a metal material having a high strength, particularly a specific gravity of 5.0 or less, and preferably titanium or a titanium alloy (described above). The head body 3 and the face member 2 may be made of the same material or different materials. It is particularly preferable to use a titanium alloy for both members.
[0015]
As shown in an enlarged view in FIG. 3, the head main body 3 is formed with a thick portion 12 having a thickness Ta in the head inner / outer direction in a region W1 extending 1 to 4 mm behind the front surface 5. The thickness Ta of the thick portion 12 is desirably 2.0 to 4.0 mm, more preferably 2.5 to 3.5 mm. On the other hand, the face member 2 forms a mounting portion 2a having a thickness Tf in the front-rear direction in a region where the face member 2 contacts the front surface 5 of the head body 3. In this example, the thickness Tf of the mounting portion 2a is set to be substantially equal to the thickness T of the center portion of the face member 2, and is 1.5 to 3.5 mm, more preferably 2.0 to 2.8 mm. It is particularly desirable to define the range. In the face member 2, the thickness Tf of the mounting portion 2a can be different from the thickness T of the central portion.
[0016]
In the head 1 of this embodiment, the ratio (Tf / Ta) of the thickness Ta of the thick portion 12 and the thickness Tf of the mounting portion 2a is limited to 0.6 to 1.2 . One of them. As shown in FIG. 4A, the face member 2 and the head main body 3 include a peripheral portion of the back surface 2B of the face member 2 (a surface opposite to the surface on which the ball is hit) and the head main body 3. The front surface 5 is joined by welding to form the head 1. Therefore, the welded portion is outside the face portion 4. At this time, as described above, by limiting the thickness ratio (Tf / Ta) between the thick portion 12 of the head body 3 and the mounting portion 2a of the face member 2 to a certain range, the thick wall that becomes the welded portion. The heat capacities of the portion 12 and the attachment portion 2a can be approximately approximated.
[0017]
That is, as shown in FIG. 4B, when the face member 2 and the head body 3 are welded, welding heat input is applied from both heat sources to the face member 2, The heat is conducted to the head body 3. At this time, the ratio of the length W1 of the thick portion 12 and the thickness Tf of the mounting portion 2a of the face member 2 to the thickness Ta of the thick portion 12 of the head body 3 is limited as described above, so that the heat capacities are made uniform. As a result, both the thick wall portion 12 and the attachment portion 2a start to be melted almost simultaneously, and the weld bead 16 can be filled across the melted portion 20 of both members as shown in FIG. 4C. Thereby, a strong welded portion between the face member 2 and the head body 3 is obtained.
[0018]
Here, when the ratio (Tf / Ta) is less than 0.5 or greater than 2, the difference between the thicknesses Tf and Ta of the face member 2 and the head main body 3 increases, and the heat capacity during welding increases. Since they are different, it is difficult to obtain a uniform melt at the same time, and the strength of the welded portion tends to decrease. From such a viewpoint, the ratio (Tf / Ta) is set to 0.6 to 1.2.
[0019]
In addition, if the thickness W1 of the thick portion 12 in the front-rear direction of the head is less than 1 mm, the effect of aligning the heat capacities tends to be reduced, and conversely if the length W4 exceeds 4 mm, the heat capacity for the face member 2 is reduced. In addition to the increase, the effective deflection area of the face portion 4 is reduced, and when a large head is used, the head weight tends to increase. From such a viewpoint, the length W1 of the region where the thick portion 12 is formed is preferably 2 to 4 mm, and more preferably 2 to 3 mm.
[0020]
The thick portion 12 as described above may be formed on at least a part of the front surface 5 of the head body 3, but more preferably, the thick portion 12 has a length along the opening 6 of the front surface 5. Is formed by 50% or more of the total length of the front surface 5, more preferably 70% or more, and even more preferably 100% (that is, the entire circumference of the crown portion 7, the sole portion 9 and the side portion 10), High weld joint strength can be obtained.
[0021]
Further, the head 1 according to the present embodiment, when welding the face member 2 and the head main body 3, for example, as shown in FIGS. 4A and 4B, the peripheral portion 2e of the face member 2 and the head main body. 3 shows an example in which a welded portion X is formed on at least one of the outer peripheral edge of the front surface 5 of No. 3. In this example, the peripheral portion 2e of the back surface 2B of the face member 2 is cut off in a chamfered shape so as to form the shank portion X. However, it may be formed on the head body 3 side, or formed on both members. You can also By providing such a thin portion X, the weld bead 16 can be stably filled between the two members, which helps to increase the joint strength of the welded portion, and improves the workability during welding work. This is preferable. The weld beads 16 that have been piled up are polished and finished so as to be flush with other parts by a polishing process.
[0022]
Further, as shown in FIG. 3, the head main body 3 according to the present embodiment has a thin portion 13 with a thickness in the head inner and outer directions smaller than the thickness Ta of the thick portion 12 behind the thick portion 12. It comprises a. The thin portion 13 of this example is connected to the first thin portion 14 having a thickness Tu1 in the head inner and outer direction of 1.2 to 1.6 mm, for example, and to the rear of the first thin portion 14 and has a thickness Tu2 of 0. And a second thin portion 15 having a thickness of 8 to 1.2 mm . The first thin portion 14 is desirably formed with a length W2 in the front-rear direction of 3 to 7 mm, more preferably 4 to 6 mm. If the length W2 is less than 3 mm, there is a tendency for the thickness to change abruptly from the thick portion 12 to the second thin portion 15. Conversely, if the length W2 exceeds 7 mm, the weight of the head increases. It tends to be unsuitable for large heads.
[0023]
Further, in this example, the second thin portion 15 forms the main portions of the crown portion 7, the sole portion 9 and the side portion 10, respectively, to help reduce the head weight. The second thin portion 15 does not necessarily need to form all of the crown portion 7, the sole portion 9, and the side portion 10, and it is sufficient if at least one portion is formed.
[0024]
As described above, since the first and second

thin portions

14 and 15 are formed behind the thick portion 12 in the head, the thickness of the head main body 3 is gradually reduced toward the rear of the head. It is possible to prevent a sudden change in thickness. This is useful for reducing the rigidity step, effectively suppressing stress concentration, and improving the durability without causing an excessive increase in the head weight. In addition, in this example, although the thick part 12 and the thin part 13 illustrated what changed thickness in a step shape, it is not limited to such an aspect. For example, as shown in FIG. 5, the thick portion 12 can be formed to have a substantially constant thickness Ta, and the thin portion 13 can be formed so as to extend rearward of the head while smoothly reducing the thickness.
[0025]
FIG. 6 shows another embodiment of the present invention.
In the present embodiment, the head main body 3 is provided with a first thin portion 14, a second thin portion 15, and a third thin portion 16 in order as a thin portion 13 behind the thick portion 12. Is done. In this case, the first thin portion 14 has a thickness Tu1 in the head inner / outer direction of 1.2 to 1.6 mm and a length W2 in the front / rear direction of 3 to 7 mm, and continues to the rear of the first thin portion 14. The thickness Tu2 of the second thin portion 15 is 0.8 to 1.2 mm, more preferably 1.0 to 1.2 mm, and the length W3 in the front-rear direction is 3 to 7 mm. Further, the thickness of the third thin portion 15 The Tu3 is preferably 0.7 to 1.0 mm.
[0026]
In this embodiment, the head 1 is made larger, the peripheral portion of the face member 2 is made relatively thicker, and the central portion of the head 1 is made thinner, thereby improving the moment of inertia and the strength of the head 1. And both. Further, the thickness Ta of the thick portion 12, the length W1, the thickness Tu1, Tu2 or Tu3 of the thin portion 13, the widths W2 and W3, and the thicknesses of the crown portion 7, the sole portion 9 and the side portion 10. The weight distribution design of the head 1 can be freely performed by changing the above in each position.
[0027]
For example, by making the thickness and length of the thick portion 12 formed on the sole portion 9 larger than those of the thick portion 12 formed on the crown portion 7 side, the weight on the sole portion 9 side is increased. Can be arranged. In this case, the position of the center of gravity of the head 1 can be made lower, and as a result, the head 1 in which the ball can easily rise can be provided. Further, the center of gravity of the head may be set closer to the toe side or the heel side by changing the thickness, length, etc. of the thick part 12 on the toe side and the thick part 12 on the heel side of the side part 10. It becomes possible.
[0028]
【Example】
A wood-type golf club head having a head volume of 320 cm ³ and substantially the same outer shape was prototyped according to the specifications shown in Table 1, and the coefficient of restitution, moment of inertia, and durability of each head were tested.
[0029]
The rebound characteristics of the face portion are S. G. A. The procedure for Measureing the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999). Specifically, a golf ball is launched using a ball launching device, collides with a sweet spot on the face of the head placed without being fixed on the pedestal, and incident velocity Vi and rebound velocity Vo immediately before the collision of the golf ball. And measure. Then, when the incident speed of the golf ball is Vi, the rebound speed is Vo, the head mass is M, and the average mass of the golf ball is m, the restitution coefficient e is calculated by the following equation.
(Vo / Vi) = (eM−m) / (M + m)
The distance from the golf ball launch port to the face portion is 55 inches, and the ball is allowed to collide at a right angle with the face surface at a position not more than 5 mm away from the sweet spot position of the head. The golf ball uses Pinnacle Gold made by Titleist, and the initial velocity of the ball is set to 160 feet ± 0.5 feet (48.768 ± 0.1524 m / s). And it evaluated by the index | exponent which sets the restitution coefficient e of the comparative example 3 to 100. The larger the value, the better.
[0030]
In addition, the inertia moment of the head is based on the inertial moment around the vertical axis and the horizontal axis passing through the center of gravity of the head in the reference state where the head is placed on the horizontal plane with the specified lie angle and loft angle, manufactured by INERTIA DYNAMICS Inc. This is a value measured using MODEL NO.005-002 of MOMENT OF INERTIA MEASURING INSTRUMENT. The greater the moment of inertia, the smaller the amount of head blurring at the time of a miss shot, and the more the flying distance loss can be suppressed.
[0031]
Furthermore, the durability was measured by launching a two-piece type golf ball using an air cannon-type launcher, colliding with the face part of the fixed head, and checking the number of damages such as cracks in the welded part ( n = 30).
Table 1 shows the test results.
[0032]
[Table 1]

[0033]
As a result of the test, it was confirmed that the head of the example can improve the durability of the welded portion, and can design the sweet spot height low and the center of gravity depth large. It was also confirmed that the moment of inertia can be designed to be larger than that of the comparative example.
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention, the length of the thick portion of the head main body, the ratio of the thickness Ta to the thickness Tf of the mounting portion of the face member (Tf / Ta), etc. are within a certain range. By limiting, it is possible to approximate the heat capacity of the thick part and the attachment part, which are the welding locations, so that at the time of welding, both the thick part and the attachment part begin to melt almost simultaneously. Therefore, it is possible to improve the bonding strength of the welded portion between the face member and the head body. Also, since the welding of the face member and the head body is performed at the peripheral edge of the back surface of the face member and the front surface of the head body, the effective deflection area of the face member is prevented from being reduced, and the rebound characteristics of the head are improved. sell.
[0035]
Further, when the thickness Ta of the thick portion and the thickness Tf of the mounting portion of the face member are limited to a certain thickness as in the invention described in claim 2, the thick portion and the mounting portion are more reliably The heat capacity can be approximately approximated, and strong welding can be achieved.
[0036]
According to a third aspect of the present invention, the head main body has a thin-walled portion provided with a thin-walled portion having a thickness in the head inner / outside direction smaller than the thickness of the thick-walled portion behind the thick-walled portion. In addition to suppressing an increase in the head weight due to the portion, the head weight can be reduced, and the moment of inertia can be increased by placing more weight around the face member of the head.
[0037]
Further, as in the inventions of claims 4 to 6, the thin portion is connected to the first thin portion having a thickness Tu1 of 1.2 to 1.6 mm in the head inner and outer direction and the rear of the first thin portion. In addition, by including the second thin portion having a thickness Tu2 of 0.8 to 1.2 mm, the thickness can be gradually reduced from the thick portion to the back of the head. Thereby, a drastic change in thickness can be prevented and the durability of the head can be improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a head according to an embodiment.
FIG. 2 is an end view taken along the line AA.
FIG. 3 is a partially enlarged view thereof.
4A to 4C are enlarged end views for explaining welding between a face member and a head main body. FIG.
FIG. 5 is an enlarged end view showing another form of the thin portion.
FIG. 6 is an enlarged end view showing another form of the head main body.
7A is an exploded perspective view of a conventional head, and FIG. 7B is a partial cross-sectional view thereof.
8A is an exploded perspective view of a conventional head, and FIG. 8B is a partial cross-sectional view thereof.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Head 2 Face member 3 Head main body 4 Face part 5 Front face 6 of head main body Opening part 7 Crown part 9 Sole part 10 Side part 12 Thick part 13 Thin part 14 First thin part 15 Second thin part 16 3rd Thin part

Claims

A plate-like face member that forms at least a part of the face portion, and a head body that has an opening for closing the face member on the front surface, and a crown portion, a sole portion, and a side portion that extend rearward from the front surface. Become
And the golf club head which joined the peripheral part of the back of the face member, and the front of the head body by welding,
The head body is formed with a thick portion having a thickness Ta in the head inside / outside direction in a region W1 extending 1 to 4 mm rearward from the front surface,
In addition, the face member forms an attachment portion having a thickness Tf in the front-rear direction in a region that contacts the front surface,
The thickness ratio (Tf / Ta) between the thick part and the attachment part is 0.6 to 1.2,
In addition, the head body includes a thin portion with a thickness Tu in the head inner and outer directions smaller than the thickness Ta of the thick portion behind the thick portion,
The thickness changes between the thick part and the thin part in a step shape ,
The thickness Ta of the thick portion is 2.0 to 4.0 mm, and the thickness Tf of the mounting portion of the face member is 1.5 to 3.5 mm.
Moreover, the thin portion is connected to the first thin portion having a thickness Tu1 in the head inner and outer direction of 1.2 to 1.6 mm, and a stepped shape behind the first thin portion, and the thickness Tu2 is 0.8. A golf club head comprising a second thin portion of about 1.2 mm .

2. The golf club head according to claim 1, wherein the thick portion is formed on an entire circumference around an opening on the front surface of the head body.

2. The first thin wall portion has a length W2 in the front-rear direction of 3 to 7 mm, and the second thin wall portion has a length W3 in the front-rear direction of 3 to 7 mm. Golf club head.

The thin-walled portion is a third thin-walled portion that continues in a step shape behind the second thin-walled portion, has a thickness Tu3 of 0.7 to 1.0 mm, and is smaller than the thickness Tu2 of the second thin-walled portion. The golf club head according to claim 1, comprising:

The face member and the head body are made of a metal material having a specific gravity of 5.0 or less and have a head volume of 300 cm. ^3Three The golf club head according to claim 1, wherein the golf club head is configured as described above.