JP2005006763A - Designing method and manufacturing method of golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a designing method of a golf club head useful for improving design efficiency, shortening a development period, and reducing a development cost, etc., and a manufacturing method. <P>SOLUTION: This designing method of the golf club head comprises: a step of primarily designing the golf club head; a step of mode-analyzing the golf club head by a computer and acquiring vibration characteristics; a step of prototyping the golf club; a step of sampling and evaluating the ball hitting sound of the prototyped golf club head; a step of specifying a head improving point for improving the ball hitting sound on the basis of the ball hitting sound and the vibration characteristics; and a step of applying the improving point and secondarily designing the golf club head. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２７】
マイクロフォンｍは、図１１に示す如く、具体的にはアドレスしたゴルファｇの耳の高さでかつゴルフボールｂと前記耳との間の水平距離ｃを、前記ゴルフボールｂからテストゴルファｇと反対側に隔てた位置に設置される。またマイクロフォンｍは、音採取部をゴルフボールｂに向けて傾けるか又は水平として設置される。前記マイクロフォンｍは、例えば１／２インチ又は１／４インチコンデンサ型マイクロフォン（測定周波数：０〜１００ｋＨｚ、フィルター特性：フラット又はＡ型、測定音圧：０〜１３０ｄＢを満たすものが好ましく、例えばリオン社製精密騒音計ＮＬ−１５がこれを満たす）が好適である。また打球音の音圧校正は、精密音圧発生器（２５０Ｈｚ、１１４ｄＢ）にて行った。なお周波数補正は行わない。
【００２８】
またマイクロフォンｍから採取された音は、記憶媒体に記録される。本例ではデジタル録音とし、ＤＡＴやハードディスクなどの記憶媒体に記録される。デジタル録音は、例えばサンプリング周波数４４ｋＨｚ 、周波数帯域０〜２０ｋＨｚ 、量子化ビット１６ビットとした。録音時間は打球音が発生する時間（大凡０．０５秒）よりも長ければ良く、通常はスイング開始からスイング終了までの連続した３ないし４秒間に設定するのが望ましい。
【００２９】
録音された打球音は、信号処理装置を用いて周波数分析が行われる。図１４に示すように、周波数分析により、打球音のパワースペクトルを得ることができる。表２には、本実施形態で使用した計測機器の一覧を示す。
【００３０】
【表２】

【００３１】
打球音の評価（ステップＳ５）は、例えば記録した打球音をアンプを介してヘッドフォン又はスピーカにて再生し、これを評価者の耳で聞いて行う。評価の基準としては、「音の高さ」、「残響長さ」、「音の強さ」、「好み」等を挙げることができ、それぞれの基準について５段階で評価しうる。ここで、打球音の評価が良好であるとの評価が得られた場合（ステップＳ６でＹ）、直前の設計案（ここでは一次設計案）を採用し、この案に従ってゴルフクラブヘッド１を製造する（ステップＳ１２）。これにより、打球音の良好なヘッド１が製造できる。
【００３２】
一方、一次設計されたヘッド１の打球音の評価結果において、例えば音が低すぎ、またそれが好ましくないこと等が判明した場合（ステップＳ６でＮ）、この打球音と前記振動特性とに基づいて、打球音を向上させる改良点を特定する（ステップＳ７）。改良点を特定するためには、先ず打球音から改善したい音の周波数帯を特定し、該音の発生要因となる部位を前記モード解析により得られた振動特性から推定する。
【００３３】
そして、この推定された部位の厚さを変更することが比較的簡単である。例えば本例の場合、打球音の低音化を防止するためには、ヘッド１から低い周波数の振動成分を取り除くことが必要である。モード解析の周波数伝達関数を精査すると、図３から低周波数域では周波数３０４８Ｈｚにピークがあることが分かる。また、この振動モードは、図４（Ａ）、（Ｂ）に示されるように、ヘッド１のソール部で生じていることが分かる。従って、打球音の好ましくない低音成分は、このソール部の振動が主な原因であることが推察できる。このように、本発明では改善したい周波数帯が分かれば、その音の発生要因を容易に特定できるため、必要に応じてその部位の厚さを増減することができ打球音の改善を容易になしうる。
【００３４】
本実施形態では、このようなヘッド改良点が特定できると、この改良点を適用してヘッドの二次設計が行われる（ステップＳ８）。「二次設計」とは、単に一次設計の結果を利用しつつその後に行われる設計工程を意味している。この二次設計では、前記の如くソール部の低周波数域での振動を防止するための構造変更が主な設計事項となる。具体的には、ソール部の厚さを増大させること、ソール部の面積を減じること、及び／又はソール部に他の材料を複合化すること等により、ソール部の剛性を高めることが行われる。
【００３５】
次に本実施形態では、前記二次設計されたヘッドを試作にするに先立ち、この二次設計のヘッドについて、コンピュータ上で前回同様のモード解析を行い振動特性を取得する処理が行われる（ステップＳ９）。二次設計されたヘッドのモード解析結果として、図１５には、イナータンスと周波数との関係を示す周波数伝達関数を、また図１６ないし図２１には、図１５の代表的なピークにおける振動モード線図をそれぞれ示している。このような処理を、試作に先立って行うことにより、二次設計の妥当性及び効果を予め確認しかつ評価することができるため、設計工程を能率化できる。
【００３６】
次に本実施形態では、改善前後の振動特性を比較して前記打球音の向上効果を確認する（ステップＳ１０）。図３と図１５との比較から明らかなように、二次設計のヘッドでは、３８９７Ｈｚに最も周波数の小さいピークが移行していることが分かる。さらに図２２には、一次設計と二次設計とのモード解析結果において、周波数伝達関数のピーク周波数の比較を示す。一次設計の振動モードの丸付数字２、３、５、６、８及び１０は、二次設計の振動モードの丸付数字１、２、４、６、８及び９にそれぞれ移行しており、いずれも周波数が大きくなっていることが分かる。これらの結果より、二次設計のヘッドは、打球音の低音化防止に十分効果があることが推察できる。
【００３７】
また、図２４、図２５には、改善前後の打球音についてのウェーブレット解析結果を示す。各グラフにおいて、縦軸は、中心周波数（Ｈｚ）、横軸は時間（秒で打球の瞬間から０．０８秒まで）を示す。また色彩は、白い部分ほど音圧が高いことを示している。本ウェーブレット解析では、縦軸が２００Ｈｚを基準として１／１２オクターブづつの分解能でで６オクターブ分を解析している。１オクターブは基準とした周波数の２倍の周波数である。各解析周波数Ｎは、次の計算式により得られる。
【数１】

【００３８】
図２４の改善前の結果では、４７９５Ｈｚ帯で音圧が高く約０．０１６秒程度しか持続（残響）していない。これに対して、図２５の改善後の結果では、４５２５Ｈｚ帯及び６４００Ｈｚ帯といった比較的高い周波数帯で各々０．０２４秒、０．０３１秒以上持続（反響）しており、人によって心地よいと感じられた音が長く続いていることが分かる。
【００３９】
次に、二次設計のヘッドにおいて改善効果が認められた場合（ステップＳ１１でＹ）、ステップＳ３に戻り、該二次設計のヘッドの試作、打球音の採取、評価（ステップＳ３〜５）を行う。図２３には、二次設計案で試作されたヘッド１の打球音のパワースペクトルを示し、鎖線は一次設計のそれを示す。この実際の打球音のパワースペクトルからも明らかなように、打球音の周波数は高音域側にシフトしていることが確認できる。そして、打球音が満足のゆくものであれば（ステップＳ６でＹ）、直前の設計案（本例では二次設計案）で打球音が良好なヘッド１を製造することができる。なおこの二次設計案でも満足のゆく打球音が得られなかった場合には、再びステップＳ７以降を繰り返し、三次設計などが行われる。
【００４０】
上記実施形態では、打球音の低音化を改善する例を示したが、これとは逆に高音化を改善することもでき、また中音域を強調させるなど種々の改良を行いうるのは言うまでもない。
【００４１】
【発明の効果】
上述したように、請求項１記載の発明では、ヘッドを一次設計するステップ、該ヘッドをコンピュータでモード解析を行い振動特性を取得するステップ、前記ヘッドを試作して打球音を採取するステップ、前記打球音と前記振動特性とに基づいて、打球音を向上させる改良点を特定するステップ及び前記改良点を適用してヘッドを二次設計するステップを含むことにより、打球音に優れたゴルフクラブヘッドを能率的に設計しうる。また、実際の打球音とモード解析との両結果を用いることによって、打球音の改良点を容易に特定することができる。これは、開発期間を短縮するのに役立つ。
【００４０】
また請求項２記載の発明のように、前記改良点を特定するステップは、打球音から改善したい音の周波数帯を特定するステップと、該音の発生要因となる部位を前記振動特性から推定するステップと、前記推定された部位の少なくとも厚さを変更するステップとを含むときには、より簡単な工程で改良点を特定することができる。
【００４１】
また請求項３記載の発明のように、二次設計されたヘッドを試作に先立ちコンピュータ上でモード解析を行い振動特性を取得するステップと、改善前後の振動特性を比較して前記打球音の向上効果を確認するステップとをさらに含むときには、ヘッドを作ることなく二次設計の効果を確認することができるため、設計工数の能率化を図ることができる。
【００４２】
また請求項４記載の発明のように、前記振動特性は、周波数応答関数及び振動モードを含むことによって、打球音の詳細な解析が可能となるため、改良点の特定がより一層容易に行える点で特に好ましい。
【００４３】
また請求項５記載の発明のように、前記打球音を採取するステップは、ゴルフクラブヘッドにシャフトを装着してゴルフクラブを試作するステップ、前記ゴルフクラブでゴルフボールを打撃するステップ、及び前記打撃時の音をマイクロフォンにて採取するステップを含み、かつ前記マイクロフォンは、アドレスしたゴルファの耳の高さでかつゴルフボールと前記耳との間の水平距離を、前記ゴルフボールからゴルファと反対側に隔てた位置に設置されることにより、ゴルファが聞き取る打撃音により近い音を採取できる。従って、打球音の解析が可能となる。
【図面の簡単な説明】
【図１】（Ａ）はウッド型ゴルフクラブヘッドの斜視図、（Ｂ）はその解析モデルを視覚化して示した斜視図である。
【図２】本発明の一実施形態を示すフローチャートである。
【図３】一次設計のゴルフクラブヘッドについて行ったモード解析の結果を示すグラフである。
【図４】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図５】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図６】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図７】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図８】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図９】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図１０】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図１１】打球音の測定条件を示す線図である。
【図１２】打球音の測定時におけるマイクロフォンの位置を示す線図である。
【図１３】打球音の測定時におけるマイクロフォンの位置を示す線図である。
【図１４】一次設計による試作ヘッドの打球音のパワースペクトルである。
【図１５】二次設計のゴルフクラブヘッドについて行ったモード解析の結果を示すグラフである。
【図１６】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図１７】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図１８】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図１９】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図２０】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図２１】（Ａ）、（Ｂ）は、特定周波数におけるモード解析結果を示すモード振動図である。
【図２２】一次設計と二次設計とのモード解析結果において、周波数伝達関数のピーク周波数の比較を示す。
【図２３】二次設計による試作ヘッドの打球音のパワースペクトルである。
【図２４】一次設計のヘッドの打球音のウェーブレット解析結果を示すグラフである。
【図２５】二次設計のヘッドの打球音のウェーブレット解析結果を示すグラフである。
【符号の説明】
１ ゴルフクラブヘッド
１Ａ 解析モデル
２ａ、２ｂ、２ｃ 要素
ｍ マイクロフォン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a golf club head design method and manufacturing method useful for efficiently manufacturing a golf club head excellent in hitting sound.
[0002]
[Prior art]
In recent years, golf club heads are mainly made of metal, and along with this, the thickness of each part can be easily changed or adjusted, and the head volume has been increased and the optimum weight distribution design has been made. . Such golf club heads are being realized at a high level in improving the direction stability of the hit ball by expanding the sweet area and improving the flight distance by increasing the coefficient of restitution. In recent years, various improvements have been made not only to increase the directionality and flight distance of the hit ball, but also to give a good impression to many golfers about the hitting feeling when hitting a golf ball, especially the hitting sound. ing. As the prior art, for example, there are the following patent documents.
[0003]
[Patent Document 1]
JP 2001-190716 A [Patent Document 2]
JP 2001-231892 A [Patent Document 3]
JP-A-10-179820 [0004]
[Problems to be solved by the invention]
Patent Document 1 teaches that the sound pressure level of the hitting sound of the golf club head is regulated to a constant value in a composite head in which a prepreg sheet and a metal material are combined. Patent document 2 teaches that the maximum value of the noise level of the hitting sound measured under a certain condition is regulated. Further, Patent Document 3 teaches that a soft hitting sound such as persimmon can be obtained by using a metal material subjected to a predetermined heat treatment for the face portion.
[0005]
By the way, in order to manufacture a head excellent in hitting sound, a golf club head is actually designed, and then a trial is made, and a test hit test is actually performed, and a hitting sound is confirmed. However, such a development method is not always efficient and tends to increase the development period or development cost.
[0006]
The present invention has been devised in view of the above problems, and provides a golf club head design method and manufacturing method useful for improving design efficiency, shortening the development period, and reducing development cost. It is intended to provide.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, the step of primary design of a golf club head, the step of performing mode analysis on the golf club head by a computer to obtain vibration characteristics, the trial production of the golf club head to produce a hitting sound A step of identifying, based on the hitting sound and the vibration characteristics, identifying an improvement point for improving the hitting sound, and a secondary design of the golf club head by applying the improvement point. This is a method for designing a golf club head.
[0008]
Further, in the invention according to claim 2, the step of specifying the improvement point includes a step of specifying a frequency band of a sound desired to be improved from the hitting sound, and a step of estimating a portion that is a cause of the sound from the vibration characteristics. A method of designing a golf club head according to claim 1, further comprising a step of changing at least a thickness of the estimated portion.
[0009]
According to a third aspect of the present invention, the step of performing mode analysis on a computer to obtain vibration characteristics prior to prototyping the secondary designed golf club head is compared with the vibration characteristics before and after the improvement, and the hitting sound is compared. 3. The golf club head design method according to claim 1, further comprising a step of confirming an improvement effect.
[0010]
The invention according to claim 4 is the golf club head design method according to any one of claims 1 to 3, wherein the vibration characteristics include a frequency transfer function and a vibration mode.
[0011]
Further, in the invention according to claim 5, the step of collecting the hitting sound includes the step of mounting a shaft on a golf club head to produce a trial golf club, the step of hitting a golf ball with the golf club, and the time of hitting Collecting the sound with a microphone, and the microphone separated the golf ball at the height of the addressed golfer's ear and the horizontal distance between the golf ball and the golfer. 4. The golf club head designing method according to claim 1, wherein the golf club head is installed at a position.
[0012]
According to a sixth aspect of the present invention, there is provided a golf club head manufacturing method for manufacturing a golf club head designed by the design method according to any one of the first to fifth aspects.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1A is a perspective view showing an example of a golf club head 1, and FIG. 2 is a flowchart showing an example of a golf club head design method. In the golf club head design method of the present embodiment, the golf club head 1 excellent in hitting sound can be efficiently designed and will be described in the following order.
[0014]
In the golf club head design method of the present embodiment, first, a primary design of a golf club head (hereinafter, simply referred to as “head”) is performed (step S1). In this embodiment, a case where a wood-type head 1 is designed is shown. As shown in FIG. 1 (A), the head 1 includes a face 2 for hitting a ball, a crown portion 3 connected to the upper edge of the face portion 2 and forming the upper surface of the head portion, and a lower edge of the face portion 2. A sole portion 4 that forms the bottom surface of the head, a side portion 5 that forms a side surface of the head between the crown portion 3 and the sole portion 4 from the toe side edge to the heel side edge of the face surface, and a shaft (not shown) are mounted. The metal thing which comprises the neck part 6 which has a hollow structure inside is illustrated.
[0015]
The “primary design” simply means the first design plan of the golf club head 1, and the dimensions, thicknesses and thicknesses of the respective parts are used to such an extent that the golf club head 1 can be prototyped at this stage. Materials etc. are determined. Although the specific method of primary design is not specifically limited, For example, it is efficient to carry out through the following steps.
[0016]
First, a basic design of a two-dimensional head is determined on a desk or a computer, and this is developed into data for forming a three-dimensional head using CAD application software (for example, “Fresdam” manufactured by Sony). At this stage, only the appearance shape (surface contour shape) is specified, and the thickness and weight of each part need not be considered. Next, the thickness of each part and its material properties (specific gravity, elastic modulus, etc.) are specifically defined in the three-dimensional head data captured in the computer. Once such specific parameters are determined, the weight, center of gravity, moment of inertia, etc. of the head can be calculated. Then, the thickness and shape of each part are appropriately adjusted so that the desired center of gravity position and moment of inertia are obtained. Such a primary design technique is useful for determining the three-dimensional shape of the head 1 relatively easily.
[0017]
Next, the first designed head 1 is subjected to mode analysis by a computer, and its vibration characteristics are acquired (step S2). The mode analysis is performed using analysis application software (for example, “ABAQUS” manufactured by HKS). Specifically, an analysis model 1A in which the head is divided into small finite elements 2a, 2b, 2c... Is defined based on the primary designed data as shown in FIG.
[0018]
As the element of the analysis model 1A, for example, a shell element and / or a tetrahedron solid element is used. The generation of the analysis model IA can be automated using a preprocessor or the like. The vertex of an element is called a node, and is shared with other adjacent elements, and one head analysis model (mesh model) IA associated as a whole is constructed. In order to increase the analysis accuracy, it is desirable that the length of one side of each element is about 1 mm. Each element is individually given information such as node coordinates, elastic modulus, Poisson's ratio, and specific gravity.
[0019]
Next, mode analysis is performed using the analysis model 1A. Mode analysis (eigenvalue analysis) is usually performed by hanging a head in the air with a thread, striking it with an impact hammer, giving the head vibration in a wide frequency band, and measuring this. In the present invention, such a mode is used. The analysis is performed by computer simulation based on the finite element method using the analysis model 1A. In the mode analysis, vibrations appear in the low rigidity portion of the analysis model 1A at a low frequency and in the high rigidity portion at a high frequency. As data input at the time of mode analysis, the elastic modulus, Poisson's ratio, and thickness (thickness) of the material are input for the shell element, and the elastic modulus and Poisson's ratio of the material are input for the solid element. Using frequency and vibration vector obtained by modal analysis. The vibration shape of each part of the head is obtained from the analysis software.
[0020]
FIG. 3 is a graph of a frequency transfer function showing the relationship between the inertia of the head and the frequency as a result of the mode analysis, and FIGS. 4 to 10 are vibration mode diagrams for typical peak frequencies of FIG. Is shown. 4 to 10, the contour lines indicate regions where the magnitudes of the vibration vectors are substantially the same. And it means that the magnitude | size of a vibration vector is so large that it approaches the center of a contour line.
[0021]
As described above, the analysis model 1A is defined using the primary designed data, and the mode analysis is performed using the analysis model 1A, so that the vibration characteristics of the head 1 can be grasped before the head 1 is actually prototyped. can do. Moreover, since this mode analysis is performed as a simulation on a computer, no actual work is performed by the worker, so that labor can be greatly reduced. If necessary, if the vibration characteristics are not clearly satisfactory, it is of course possible to redo the primary design.
[0022]
Next, the primary designed head is actually manufactured as a prototype, and the hitting sound is collected and evaluated (steps S3 to S5). The head is prototyped according to the primary design plan. In this embodiment, the head 1 made of a titanium alloy is manufactured by the lost wax precision casting method. The cast head 1 is formed, for example, by dividing it into a face member and a head main body having the face member disposed on the front surface, and both of them are fixed by welding and appropriately subjected to a polishing process or the like by a belt sander. The head 1 is manufactured.
[0023]
Further, the measurement of the hitting sound of the head can be performed, for example, in the following steps. First, a golf club is prototyped by mounting a shaft on the prototyped head 1, and a hitting test for hitting an actual golf ball is performed using this golf club. And the sound at the time of impact is sampled with a microphone. FIG. 11 shows preferable conditions for measuring such a hitting sound.
[0024]
The location where the impact test is performed may be indoors or outdoors, but it is preferable to perform the impact test in the absence of windshields that are preferably outdoors and have no shielding material that reflects sound within a radius of 50 m. Although there is no particular limitation on the golfer g, a standard average golfer having a height of about 160 to 180 cm and a head speed at the time of hitting of about 38 to 48 m / s is preferable. The golf ball b is not particularly limited as long as it can be used for a golf competition. Further, the hitting sound does not substantially change depending on the head speed, the swing habit, the golf ball (separate from thread winding or solid), etc., but may change depending on the position of the face portion hitting the ball. For this reason, a shot mark in which the hit point position remains (the hitting sound does not substantially change depending on the presence or absence of the shot mark) is attached to the face surface of the head 1, and the center of the hit point is within a circle with a radius of 5 mm from the face center. It is desirable to collect the hitting sound when entering.
[0025]
The hitting sound is collected by the microphone m. Since the collected sound differs depending on the installation position of the microphone m, the installation position of the microphone m is important. The inventors conducted an experiment on the relationship between the installation position of the microphone m and the reproducibility of the hitting sound. First, as shown in FIG. 12 and FIG. 13, the hitting sounds are collected and recorded by microphones installed at a plurality of positions, and each sound is heard by the test golfer g and feels close to the most memorized hitting sound. I chose. The test was conducted by six test golfers. The test results are shown in Table 1. From the test results, it was found that the microphone m shown in FIG. 11 can collect a sound closest to the actual hitting sound. In the present embodiment, the installation position of the microphone m is determined based on such experimental results.
[0026]
[Table 1]

[0027]
As shown in FIG. 11, the microphone m is specifically the height of the ear of the addressed golfer g and the horizontal distance c between the golf ball b and the ear is opposite from the golf ball b to the test golfer g. It is installed at a position separated to the side. Further, the microphone m is installed such that the sound collection part is inclined toward the golf ball b or is horizontal. The microphone m is preferably a 1/2 inch or 1/4 inch condenser microphone (measuring frequency: 0 to 100 kHz, filter characteristics: flat or A type, measuring sound pressure: 0 to 130 dB, for example, Rion Corporation It is preferable that the precision sound level meter NL-15 manufactured by this company satisfy this). The sound pressure calibration of the hitting sound was performed with a precision sound pressure generator (250 Hz, 114 dB). Frequency correction is not performed.
[0028]
The sound collected from the microphone m is recorded on a storage medium. In this example, digital recording is performed, and recording is performed on a storage medium such as DAT or a hard disk. For digital recording, for example, the sampling frequency is 44 kHz, the frequency band is 0 to 20 kHz, and the quantization bit is 16 bits. The recording time only needs to be longer than the time when the hitting sound is generated (approximately 0.05 seconds), and it is usually desirable to set the recording time to 3 to 4 seconds continuous from the start of the swing to the end of the swing.
[0029]
The recorded hitting sound is subjected to frequency analysis using a signal processing device. As shown in FIG. 14, the power spectrum of the hitting sound can be obtained by frequency analysis. Table 2 shows a list of measuring devices used in the present embodiment.
[0030]
[Table 2]

[0031]
The evaluation of the hitting sound (step S5) is performed by, for example, reproducing the recorded hitting sound with a headphone or a speaker via an amplifier and listening to it with an evaluator's ear. Examples of evaluation criteria include “sound pitch”, “reverberation length”, “sound intensity”, “preference”, and the like, and each criterion can be evaluated in five stages. Here, when the evaluation that the evaluation of the hitting sound is good (Y in Step S6), the immediately preceding design plan (here, the primary design plan) is adopted, and the golf club head 1 is manufactured according to this plan. (Step S12). Thereby, the head 1 with favorable hitting sound can be manufactured.
[0032]
On the other hand, in the evaluation result of the hitting sound of the head 1 designed primarily, for example, when it is found that the sound is too low and is not preferable (N in step S6), based on the hitting sound and the vibration characteristics. Then, an improvement point that improves the hitting sound is specified (step S7). In order to identify the improvement point, first, the frequency band of the sound to be improved is identified from the hitting sound, and the part that causes the sound is estimated from the vibration characteristics obtained by the mode analysis.
[0033]
It is relatively easy to change the estimated thickness of the part. For example, in the case of this example, it is necessary to remove a low-frequency vibration component from the head 1 in order to prevent the hitting sound from being lowered. Examining the frequency transfer function of the mode analysis, it can be seen from FIG. 3 that there is a peak at a frequency of 3048 Hz in the low frequency range. Further, it can be seen that this vibration mode occurs at the sole portion of the head 1 as shown in FIGS. 4 (A) and 4 (B). Therefore, it can be inferred that the unfavorable bass component of the hitting sound is mainly caused by the vibration of the sole portion. Thus, in the present invention, if the frequency band to be improved is known, the cause of the sound can be easily identified, so that the thickness of the part can be increased or decreased as necessary, and the hitting sound can be easily improved. sell.
[0034]
In this embodiment, when such a head improvement point can be specified, the head is subjected to secondary design by applying this improvement point (step S8). The “secondary design” means a design process performed after using the result of the primary design. In the secondary design, as described above, the structural change for preventing the vibration of the sole portion in the low frequency region is the main design matter. Specifically, the rigidity of the sole portion is increased by increasing the thickness of the sole portion, reducing the area of the sole portion, and / or combining other materials with the sole portion. .
[0035]
Next, in the present embodiment, prior to making the secondary-designed head as a prototype, the secondary-designed head is subjected to a mode analysis similar to the previous time on the computer to obtain vibration characteristics (step) S9). As a result of mode analysis of the secondary designed head, FIG. 15 shows a frequency transfer function indicating the relationship between inertance and frequency, and FIGS. 16 to 21 show vibration mode lines at typical peaks in FIG. Each figure is shown. By performing such processing prior to prototyping, the validity and effect of the secondary design can be confirmed and evaluated in advance, so that the design process can be streamlined.
[0036]
Next, in this embodiment, the improvement effect of the hitting sound is confirmed by comparing the vibration characteristics before and after the improvement (step S10). As is clear from the comparison between FIG. 3 and FIG. 15, it can be seen that the peak with the lowest frequency is shifted to 3897 Hz in the head of the secondary design. Further, FIG. 22 shows a comparison of peak frequencies of the frequency transfer function in the mode analysis results of the primary design and the secondary design. The primary design vibration mode circled numbers 2, 3, 5, 6, 8 and 10 have moved to the secondary design vibration mode circled numbers 1, 2, 4, 6, 8, and 9, respectively. It can be seen that the frequency is increased in both cases. From these results, it can be inferred that the head of the secondary design is sufficiently effective in preventing the hitting sound from being lowered.
[0037]
24 and 25 show the wavelet analysis results for the hitting sounds before and after the improvement. In each graph, the vertical axis represents the center frequency (Hz), and the horizontal axis represents time (in seconds, from the moment of hitting the ball to 0.08 seconds). The color indicates that the white portion has a higher sound pressure. In this wavelet analysis, the vertical axis is analyzed for 6 octaves with a resolution of 1/12 octave with 200 Hz as a reference. One octave is twice the reference frequency. Each analysis frequency N is obtained by the following calculation formula.
[Expression 1]

[0038]
In the result before improvement in FIG. 24, the sound pressure is high in the 4795 Hz band and lasts only about 0.016 seconds (reverberation). On the other hand, in the result after the improvement in FIG. 25, it persists (resonates) over 0.024 seconds and 0.031 seconds in the relatively high frequency bands such as the 4525 Hz band and the 6400 Hz band, respectively, and it feels comfortable for people. It can be seen that the recorded sound continues for a long time.
[0039]
Next, when the improvement effect is recognized in the head of the secondary design (Y in step S11), the process returns to step S3, and the prototype of the head of the secondary design, sampling of the hitting sound, and evaluation (steps S3 to S5) are performed. Do. FIG. 23 shows the power spectrum of the hitting sound of the head 1 prototyped by the secondary design plan, and the chain line shows that of the primary design. As is apparent from the power spectrum of the actual hitting sound, it can be confirmed that the frequency of the hitting sound is shifted to the high sound range side. If the hitting sound is satisfactory (Y in step S6), the head 1 having a good hitting sound can be manufactured with the immediately preceding design plan (secondary design plan in this example). If a satisfactory hitting sound is not obtained even with this secondary design plan, step S7 and subsequent steps are repeated again to perform tertiary design and the like.
[0040]
In the above embodiment, an example of improving the lowering of the hitting sound has been shown. However, it goes without saying that the higher pitch can be improved and various improvements such as emphasizing the midrange can be made. .
[0041]
【The invention's effect】
As described above, in the first aspect of the invention, the step of primary design of the head, the step of performing mode analysis with the computer to acquire vibration characteristics, the step of sampling the head and sampling the hitting sound, A golf club head excellent in hitting sound by including a step of identifying an improved point for improving the hitting sound based on the hitting sound and the vibration characteristic and a step of secondary designing the head by applying the improved point Can be designed efficiently. Moreover, the improvement point of the hitting sound can be easily identified by using both the actual hitting sound and the result of the mode analysis. This helps to reduce development time.
[0040]
According to a second aspect of the present invention, the step of specifying the improvement point includes a step of specifying a frequency band of a sound desired to be improved from the hitting sound, and a portion that causes the sound is estimated from the vibration characteristics. When including a step and a step of changing at least the thickness of the estimated portion, the improvement point can be specified by a simpler process.
[0041]
Further, as in the third aspect of the invention, the step of obtaining a vibration characteristic by performing a mode analysis on a computer prior to trial manufacture of a secondary-designed head is compared with the vibration characteristic before and after the improvement to improve the hitting sound. When the step of confirming the effect is further included, since the effect of the secondary design can be confirmed without making a head, the efficiency of the design man-hour can be improved.
[0042]
In addition, since the vibration characteristic includes a frequency response function and a vibration mode as in the invention described in claim 4, it is possible to perform a detailed analysis of the hitting sound, so that the improvement point can be identified more easily. Is particularly preferable.
[0043]
According to a fifth aspect of the present invention, the step of collecting the hitting sound includes the step of mounting a shaft on a golf club head to manufacture a trial golf club, the step of hitting a golf ball with the golf club, and the hitting Collecting the sound of the time with a microphone, and the microphone is at the height of the addressed golfer's ear and the horizontal distance between the golf ball and the ear from the golf ball to the opposite side of the golfer. By being installed at a separated position, it is possible to collect a sound closer to the hitting sound heard by the golfer. Therefore, it is possible to analyze the hitting sound.
[Brief description of the drawings]
FIG. 1A is a perspective view of a wood type golf club head, and FIG. 1B is a perspective view of an analysis model visualized.
FIG. 2 is a flowchart showing an embodiment of the present invention.
FIG. 3 is a graph showing the results of mode analysis performed on a primary design golf club head.
4A and 4B are mode vibration diagrams showing mode analysis results at a specific frequency. FIG.
FIGS. 5A and 5B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
6A and 6B are mode vibration diagrams showing mode analysis results at a specific frequency. FIG.
FIGS. 7A and 7B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
8A and 8B are mode vibration diagrams showing mode analysis results at a specific frequency.
9A and 9B are mode vibration diagrams showing mode analysis results at a specific frequency.
FIGS. 10A and 10B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
FIG. 11 is a diagram showing measurement conditions for hitting sound.
FIG. 12 is a diagram showing the position of the microphone at the time of measuring the hitting sound.
FIG. 13 is a diagram showing a position of a microphone when measuring a hitting sound.
FIG. 14 is a power spectrum of the hitting sound of the prototype head according to the primary design.
FIG. 15 is a graph showing the results of mode analysis performed on a golf club head of secondary design.
FIGS. 16A and 16B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
FIGS. 17A and 17B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
18A and 18B are mode vibration diagrams showing mode analysis results at a specific frequency.
19A and 19B are mode vibration diagrams showing mode analysis results at a specific frequency.
20A and 20B are mode vibration diagrams showing mode analysis results at a specific frequency.
FIGS. 21A and 21B are mode vibration diagrams showing mode analysis results at a specific frequency. FIGS.
FIG. 22 shows a comparison of peak frequencies of frequency transfer functions in the mode analysis results of the primary design and the secondary design.
FIG. 23 is a power spectrum of the hitting sound of the prototype head according to the secondary design.
FIG. 24 is a graph showing the result of wavelet analysis of the hitting sound of the head of the primary design.
FIG. 25 is a graph showing the wavelet analysis result of the hitting sound of the head of the secondary design.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Golf club head 1A Analysis model 2a, 2b, 2c Element m Microphone

Claims (6)

Primary design of golf club head,
Performing a mode analysis on the golf club head with a computer to obtain vibration characteristics;
Collecting a hitting sound by making a prototype of the golf club head;
A golf club head comprising: specifying an improvement point for improving the hitting sound based on the hitting sound and the vibration characteristic; and applying a secondary design of the golf club head by applying the improvement point. Design method. The step of specifying the improvement point is a step of specifying a frequency band of a sound to be improved from the hitting sound;
Estimating a site that is a cause of the sound from the vibration characteristics;
The method of designing a golf club head according to claim 1, further comprising a step of changing at least a thickness of the estimated portion. Obtaining a vibration characteristic by performing mode analysis on a computer prior to trial production of the secondary designed golf club head;
The golf club head design method according to claim 1, further comprising a step of confirming the effect of improving the hitting sound by comparing vibration characteristics before and after the improvement. 4. The golf club head design method according to claim 1, wherein the vibration characteristics include a frequency transfer function and a vibration mode diagram. The step of collecting the hitting sound includes the step of mounting a shaft on a golf club head and making a trial golf club;
Hitting a golf ball with the golf club, and collecting a sound at the time of hitting with a microphone,
The microphone is installed at a position at the height of the ear of the addressed golfer and at a horizontal distance between the golf ball and the ear on the opposite side from the golf ball. Item 4. A golf club head design method according to Item 1. 6. A golf club head manufacturing method, comprising: manufacturing a golf club head designed by the design method according to claim 1.

Images