JPS6122874A - Ball hitting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a ball hitting tool for sports.

Generally speaking, taking a golf club as an example of a ball hitting tool, the action of the golf club for hitting a golf ball can be summarized as follows. That is, among these, spin, launch angle, and directionality are mechanically explained by focusing on the moment of inertia around the center of gravity of the club head. Furthermore, head speed is explained with a focus on the shaft in relation to swing. Conventionally, it has been said that by making the natural frequency of this shaft the same within the club center or creating a certain difference, effects such as ``swinging smoothly'' and ``swinging with the same rhythm'' have been cited.
The current situation is that it has not been clarified theoretically.

In particular, the problem of the repulsion coefficient is a problem between the golf ball and the golf club, and the impact of the club (head) not reaching this repulsion coefficient at the time of collision (hitting) is as follows.
Until now, this had not been disclosed at all.

By the way, conventional golf clubs have been made of materials such as Versimmon (persimmon wood), ABS resin, carbon fiber reinforced resin (hereinafter sometimes abbreviated as CFRP), aluminum, stainless steel, and the like. Regarding these 4A, it has been said that the harder the material, the better the repulsion from the golf ball and the higher the initial velocity of the ball.

Blue Damo compressed material is used instead of persimmon, and carbon fiber reinforced resin (CFRP) is required to have a high fiber whiteness ratio, and it has been thought that it has a high repulsion coefficient because it is hard.

The present invention breaks this conventional wisdom, and as a result of repeated numerous experiments over many years, we have found the optimal hardness to maximize the ball's rebound and maximize the ball's initial velocity. It has been found that exceeding this optimum hardness results in poor repulsion. Going further, they discovered that the mechanical impedance of the ball and hitting tool was involved.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ball hitting tool that increases the coefficient of repulsion when hitting a ball and brings the initial velocity of the ball closer to its maximum. So, the characteristics of the present invention are as follows.
The main part of the hitting part or the entire hitting part is configured so that the mechanical impedance of the hitting part shows a minimum value in a frequency region near the frequency where the mechanical impedance of the object to be hit shows a minimum value. That's what I did.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

First, to explain the mechanical impedance of a mechanical system, it is defined as "the ratio of the response of a force acting on a certain point to the response of another point." That is, assuming that the input is F and the response speed is ■, the mechanical impedance Z is defined as z=-□■.

FIG. 3 is a diagram illustrating how the mechanical impedance of a golf ball changes, with the vertical axis representing the absolute value of the mechanical impedance Z of a general golf ball and the horizontal axis representing frequency. The measurement was performed using a frequency analyzer (+"FT analyzer) known in the field of mechanical vibration. (For example, Yokogawa Heuret Packer■
The model 5420 A made by the company is used. ) In this Figure 3, the frequency range 0 to 10,000 Hz (
It can be seen that the golf ball has 2 to 5 minimum values P... within H2). Moreover, the first minimum value P 6;
I, the frequency N is around 3000 Hz.

The frequency exhibiting this minimum value P is the so-called natural frequency (cJ), which is determined by the mass-spring system of the structure (ball).

On the other hand, FIG. 1 or 2 shows the results of measuring the mechanical impedance of a wood-type golf club as an example of a ball-hitting tool in a frequency range of 0 to about 12,000 hertz. However, mechanical impedance (vertical axis)
is expressed as a value obtained by taking the absolute value as a logarithm and multiplying it by 20.

Virtual line 1 shows a conventional example, and all existing wood-type golf clubs (including those called carbon heads and metal heads) do not have a clear minimum value in the frequency range of 0 to 10,000 Hz. .

Specifically, in the ball hitting tool according to the present invention, the mechanical impedance Z of the part of the entire golf club head that directly hits the ball is set to curves C, D, E or second curve in FIG.
As shown by the solid line 2 or broken line 3 in the figure, the mass distribution of the club head, shaft, etc., the spring constant, This is to set the damping coefficient.

To explain the embodiment more specifically, in FIG. 4, consider a dividing line a-b that passes through the center point 5 of the face surface 4 where the ball is hit and is perpendicular to the face surface 4. If the club head 6 is divided into three parts by straight lines La and Lb that pass through the points Qa and Qb that divide into three equal parts and are perpendicular to the line a-b, then the center of gravity G of the club head 6 will be on the straight line 1. , a (; is close to l. In other words, the center of gravity G is approximately l/3 from the face surface 4, and the ratio of the masses of the three parts is M, :M2:M3=5:3: 2 Tozui). (This mass ratio is approximately equivalent to that of a conventional club head) up to j'. ) Therefore, as shown in FIG. 5, for the inlays 1-7 of the face 4, a material with a spring constant k significantly smaller than that of the conventional material is used. For example, the spring constant is '=8000''.
20000kg/cm, thickness T-8m, width -j
If an insert 7 with a diameter of W-40I1m and a height of H'=40 mm is used, a local minimum value (2) appears in the frequency range from 0 to 10,000 Hz.

Preferably, the minimum value P appears in the frequency range of 1500 to 8000 hertz. It is particularly preferable (judging from the initial velocity of the ball to be described later) that the minimum value P appears within 2,000 to 6,000 hertz, taking into consideration the compatibility with general golf balls having the characteristics as shown in FIG. Then, it can be said that the optimum value is to make the minimum value P appear in the frequency range of 2,500 to 4,000 hertz.

In this way, by making the spring constant 1 of the material of the insert 7 sufficiently smaller than the spring constant of conventional ABS resin, carbon fiber reinforced resin laminate, or metal plate such as aluminum, o = 10000 Hz. A club that exhibits one to several minimum values P at a predetermined frequency within the golf club can be obtained.In particular, this method has the advantage that the mass distribution and shape of a conventional golf club can be maintained as they are.

Therefore, conventional examples A-B and embodiments C and D' of the present invention
Descriptions of the types of golf clubs of H and actual measurement results (average values of many actual measurements) are shown in FIG. 1 and (Table I). (The ball used was a two-piece ball with an ionomer resin cover.) The following can be seen from Table 1 and FIG. 1.

Conventional example A uses Versimmon head base material with Δ13S4?
Although the rl Ili insert is installed as shown in FIG. 5, it does not show any minimum value P within the frequency θ to 10,000 Hz. However, a spring constant of 80,000 kI? /
cm O) CF I? In conventional example B, in which the P insert is placed in the carbon head's mother H, the frequency is 10.
It shows a minimum value when it exceeds 00011z. frequency 1
The ball initial velocity of Conventional Example B was the same as that of Conventional Example A, or was slightly worse than that of Conventional Example A.

On the other hand, in Examples C-D'-E of the present invention, the spring constant K is 20000' and 10000.8000 kg.
/c+n (7)? It is an ionomer resin, and clearly shows the minimum value P at frequencies of 7200.5250° and 3800Hz, respectively, and when the head speed is constant at 45 m/5ec for each club, the initial ball speed vb of the dogs
Comparing with Conventional Example A, Example C-□0.46 m/
sec increase, Example D = 0.71 m/sec increase,
Example E = 1', 98 m/sec increase.

This corresponds to an increase in carry of a golf ball of 2 to 8 m. (A significant increase in carry was confirmed.) Next, Figure 2 and (Table 2) show other measurement results. The conventional example is shown by a virtual line l, but the minimum value does not appear. This is a carbon head base material with an ABS resin insert attached. Further, in this experiment C, measurements were made on two types of balls.

This (Table 2) also shows that the ball initial velocity of the embodiment of the present invention (solid line 2 and broken line 3) is definitely higher than that of the conventional example (phantom line 1). Furthermore, from a large number of actual measurement results,
The value of mechanical impedance Z at the minimum value P is
Mechanical impedance Z at nearby frequencies
If it shows a value smaller than 5 decihers (dB) compared to , it can be said that the above-mentioned increase in the initial ball speed is significant.

Note that mechanical impedance is influenced by the mass distribution of the object, the spring constant, and the damping coefficient. By changing the material and structure of the golf club, it is possible to configure the entire golf club so that the minimum value is within the frequency range θ~100(1(+-\).Also, the insert 7 may be made of polycarbonate or It is also possible to adjust the spring constant using an engineering plastic tensioner so that it shows the same minimum value P...

In addition, in the above-mentioned embodiment, the golf club as a whole is configured so that the minimum value appears in the mechanical impedance of the face surface that directly hits the ball in a predetermined frequency range. It is also desirable to design only the club head 6 so that the mechanical impedance of the face surface shows a minimum value in a predetermined frequency range. Furthermore, Fig. 5 shows a ball hitting tool,
In addition to the golf club 8, a tennis racket 9, a baseball bat 10, or a table tennis racket 11 are exemplified, and for any of these hitting tools, the mechanical impedance of a tennis ball, a baseball ball, and a bing pong ball are minimum values. Find the frequency that shows the minimum value of the object being hit, and set the mass distribution, spring constant, etc., depending on the material, shape, structure, etc., so that the hit object shows the minimum value in the nearby frequency region where the minimum value is shown.The initial velocity of the ball can be increased. increases, and flight distance increases. The present invention can be widely applied to ball hitting tools for various sports.

In the embodiment of the golf club of the present invention, the main hitting part of the golf club is constructed so that the mechanical impedance of the part that directly hits the golf ball shows a minimum value in the frequency range of 0 to 10,000 Hz. Therefore, regardless of whether the hardness of the part of the pole that is directly hit is not high, the repulsion of the pole is large (by breaking the conventional dense weave), the initial velocity of the pole can be increased, and an increase in flight distance can be achieved. This is a golf club that is adjusted according to the mechanical impedance characteristics of the golf club.

As described in detail below, the present invention provides a method for controlling the striking main body so that the mechanical impedance of the striking part shows a minimum value in a frequency region near the frequency showing the minimum value of the mechanical impedance of the object to be hit. Since it is a ball hitting tool composed of parts or the whole, it is the best combination with the object to be hit (such as a pole), and the maximum return can be obtained, thereby increasing the flight distance of the object to be hit.

[Brief explanation of the drawing]

Figures 1 and 2 show different actual measurement results, and are diagrams of mechanical impedance characteristic curves comparing the example of the ball hitting tool according to the present invention and the conventional example, and Figure 3 shows the mechanical impedance of the pole. Characteristics FIG. 5 is a perspective view showing one embodiment of the present invention, and FIG. 6 is a diagram showing specific examples of various ball hitting tools. 7...Insert, mechanical impedance for Z,
P...Minimum value, N...Frequency.

Claims (1)

[Claims] 1. The main part to be hit or the entire part to be hit is made so that the mechanical impedance of the part to be hit shows a minimum value in a frequency region near the frequency where the mechanical impedance of the object to be hit shows a minimum value. A striking tool characterized by comprising: 2. The ball hitting tool according to claim 1, wherein the main part or the entire hitting part is configured such that the mechanical impedance of the part that directly hits the ball shows a minimum value in the frequency range of 0 to 10,000 Hz. . 3. The ball hitting tool according to claim 1, wherein the frequency range showing the minimum value is 1500 to 8000 hertz. 4. The ball hitting tool according to claim 1, wherein the frequency range showing the minimum value is 2000 to 6000 hertz.