JPS61284265A - Ball hitting tool - 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] [Industrial application field] The present invention relates to a ball hitting tool for sports.

[Conventional technology and its problems]

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.

However, the problem of repulsion coefficient is a problem between the golf ball and the golf club, and at the time of collision (hit),
Until now, the influence of the club (head) on this repulsion coefficient has not been clarified at all.

In general, conventional golf clubs have been made of materials such as persimmon (rod material), ABS resin, carbon fiber reinforced resin (hereinafter sometimes abbreviated as CFRP), aluminum, stainless steel, and the like. Conventionally, it has been thought that the harder a material is, the easier it is for a golf ball to rebound (larger the coefficient of repulsion) and the higher the initial velocity of the ball.

Blue Damo compressed material is used instead of persimmon, and carbon fiber reinforced resin (CF RP) is required to have a high fiber content, 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. They went further and discovered that the mechanical impedance of the ball and ball hitting tool was involved.

〔the purpose〕

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.

[Means for solving problems]

According to the present invention, the mechanical impedance of the hitting portion that hits the ball has a first-order minimum value in a frequency region near the frequency at which the mechanical impedance of the ball shows the first-order minimum value.

[For production]

The ball exhibits a unique mechanical impedance corresponding to the frequency of the applied mechanical vibration, and the striking portion of the ball hitting tool also exhibits a unique mechanical impedance. The frequency at which each mechanical impedance exhibits a minimum value corresponds to the natural frequency.

Then, when the frequency of the applied mechanical vibration is gradually increased from zero, the minimum value that first appears □
That is, the first-order minimum value □ corresponds to the first-order natural frequency.

The frequency □ at which the mechanical impedance of the hitting part of the ball hitting tool is a minimum value, that is, the natural frequency □ of the ball hitting tool is the frequency at which the mechanical impedance of the ball is a minimum value - that is,
If the ball hitting tool is configured to approximate the natural frequency □ of the ball, the repulsion coefficient will increase. In particular, among the natural frequencies such as primary, secondary, and tertiary, the primary one has the greatest influence, and the primary natural frequency of the ball hitting tool becomes the primary natural frequency of the ball. Maximum repulsion is obtained by approximation.

〔Example〕 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 between the magnitude of a force acting on a certain point and the magnitude of the response speed at other points when this force is applied." That is, assuming that the force applied from the outside is F and the response speed is V, the mechanical impedance Z is defined as (2).

The ball hitting tool 1 according to the present invention includes a golf club 8, a tennis racket 9, and a baseball bat 1 illustrated in FIGS. 5A to 5D.
0 and ping pong rackets 11, etc., and are used in ball sports.

In Figure 2, the horizontal axis is the ball hitting tool! Or take the frequency N (11th place: Hz) of the mechanical vibration applied to the ball,
The vertical axis is the logarithm of the absolute value of mechanical impedance Z.
The value multiplied by 0 is taken to show how the mechanical impedance Z changes depending on the frequency N. As is clear from the figure, both the ball hitting tool 1a and the ball hitting tool 1b show a first-order minimum value at point P1 and a second-order minimum value at point P2, which are not shown in the figure. In the right outside, the minimum values of cubic, quartic, etc. are further shown. Also, as shown by the broken line in the figure, the hit ball similarly shows the minimum values of linear and quadratic at points PL and P2, respectively. shows the minimum value of (Additionally, the minimum values of tertiary and higher orders are shown outside the figure.) These first order, second order,...
Point Pl indicating the minimum value of.

The frequencies of P2 are so-called primary, secondary, etc. natural frequencies, and are determined by the [mass-spring] system of the ball-hitting tool and ball as structures.

3A, 3B to 3E, and 4 show the method of measuring the mechanical impedance Z, that is, 12 is an excitation machine, and an electrodynamic or hydraulic type is used;
The ball 2 is attached to the specimen mounting base 13. Alternatively, as the ball hitting tool 1, a golf club 8, a tennis racket 9,
100 baseball bats or 11 ping pong rackets,
The specimen is mounted on the specimen mounting stand 13. Specifically, among the members constituting the ball hitting tool 1, the hitting part 3 for hitting the ball is attached to the specimen mounting base 13, and vibrations are transmitted to the hitting part 3. In FIG. 3B, the hitting part 3 is the club head 8a, in FIG. 2C, the hitting part 3 is the gut surface 9a that hits the tennis ball, and in FIG. 3D, the part where the baseball ball is directly hit (the In FIG. 3E, it is the blade portion 11a of the ping-pong racket 11.

A first acceleration pickup 14 is fixed to the specimen mounting base 13 of the vibrator 12, and a second acceleration pickup 15 is further fixed to the hitting portion 3 of the ball hitting tool 1 or the ball 2. 1st
From the acceleration pickup 14, the mounting base 1 of the vibration exciter 12 is connected.
The acceleration A1□ of No. 3, that is, the acceleration applied to the ball hitting tool 1 or the ball 2 from the outside, is output, and this output is input to the dynamic signal analyzer 17 via the power unit 16.

The second acceleration pickup 15 outputs the acceleration A2 of the ball 2 or the ball hitting tool 1, which is the specimen, and inputs this output to the dynamic signal analyzer 17 via another power unit 18. The dynamic signal analyzer 17 determines the ratio of both speeds □, that is, the transfer function T=A2/Al□, and calculates this in the frequency domain to determine the mechanical impedance Z=F1/v2. This mechanical impedance 2 is displayed on the display 19 in the graph shown in FIG. In the actual measurement test of the implementation product of the present invention,
As each measuring device in FIGS. 3 and 4, the manufacturers and types of equipment shown in Table 1 below were used.

Table 1 Measuring device used in actual measurement test The measuring method using the above-mentioned measuring device has the advantage that the first-order minimum value of mechanical impedance Z can be clearly confirmed.

Therefore, in Fig. 2 and Figs. 3A to 3E, ball 2
If the frequency at which the mechanical impedance Z of the ball hitting tool 1 of the present invention exhibits the first-order minimum value P1 is Nb, then the mechanical impedance Z of the ball-striking tool 1 according to the present invention falls within the frequency range D □ in the shaded area □ in FIG. Then, the first-order minimum value P1
The physical characteristics of the ball hitting tool 1, such as the mass distribution and the spring constant of each component, are selected as shown in FIG.

(1-n> ・Nb5N≦(1+n) ・Nb
−■ However, 0≦n≦0.3 Specifically, one ball-striking tool 1a shows a first-order minimum value near the lower limit of frequency N that satisfies the above formula (■), and the other ball-striking tool ib shows the above formula A first-order minimum value is shown near the upper limit of frequency N that satisfies (2).

In this formula (■), n=0.3. n=0.2. n=0.1. n
=0°05 respectively, the frequency domain becomes 0.0.
7Nb 5N≦1.3Nb ...■0.8N
b≦N≦1.2Nb ・・・■0.9Nb≦N
51. INb...■0.95Nb≦N≦1
．． 05Nb...It is represented by the following formulas.

In the frequency range that satisfies any of the above formulas,
The ball hitting tool l according to the present invention is configured such that a first-order minimum value P1 of the mechanical impedance Z exists.

In other words, from 70% of the frequency Nb at which the mechanical impedance 2 of the ball 2 exhibits the first minimum value P1.
130%, 80% to 120%, 90% to 110%, or
In the frequency range corresponding to 95% to 105%, the mechanical impedance 2 of the ball hitting tool 1 has a first-order minimum value P1
The ball hitting tool 1 is configured as shown in FIG. Here, 7
A sufficiently large repulsion coefficient can be obtained with a coefficient of 0% to 130%, but the most excellent ball repulsion can be obtained with a coefficient of repulsion of 95% to 105%.

Fig. 1 shows the results of actual measurements using the same measuring device and the same measuring method as in Fig. 2, taking a golf club as an example of a hitting tool and a golf club as a ball. is shown by broken line B. It shows a first-order minimum value P1 at the frequency Nb = 1150Hz, and further shows second-order and third-order minimum values P2 at N-3600 and 5450Hz, respectively. It can be seen that P3 is indicated. The frequency Nb at which the first-order minimum value PI occurs varies depending on the structure of golf balls currently on the market (one-piece ball, two-piece ball, three-piece ball, thread-wound ball, etc.). ≦
Nb≦1600...This frequency Nb exists in the range indicated by ■.

The results of actually measuring the mechanical impedance of a conventional golf club are shown by thin solid lines n and m in the figure. The golf club indicated by the solid line (■) is a conventionally commonly used wood-type club having a head made of Persimmon, and the frequency N of the first-order minimum value P1 is 2050 Hz. Another golf club indicated by the solid line (■) is a conventionally commonly used wood-type club having a carbon head, and the frequency N of the first-order minimum value P1 is 2225 Hz. Therefore, the frequency N at which the mechanical impedance Z of the conventional golf club exhibits the first-order minimum value P1 is significantly outside the frequency range near the frequency at which the mechanical impedance Z of the golf ball exhibits the first-order minimum value P1.

Based on the above-mentioned technical idea of the present invention, a wood-type golf club whose mass distribution of the club head, shaft, etc., as well as spring constant and damping coefficient are set, draws a curve as shown by the thick solid line ■, and has mechanical impedance 2. The frequency N showing the first-order minimum value P1 was 1250 Hz. That is,
In formula (2), this corresponds to n=0°087. The minimum value P1 of this golf club exists in a frequency range drawn to satisfy the equation (2) in FIG.

This golf club according to the present invention shown in FIG. 1 (referred to as I), the conventional golf club having a Versimmon head (referred to as Golf clubs with carbon heads (
Table 2 shows a comparison of the performance of (referred to as (1)). The ball has the characteristics shown by the broken line B in the same figure.
A live firing test was conducted using a peace ball (ionomer resin cover).

The following can be seen from Table 2 and Figure 1. That is, the mechanical impedance 2 of the golf ball is the first minimum value P
The closer the frequency Nb -1, that is, the first-order natural frequency □, where the mechanical impedance Z of the golf club shows the first-order minimum value P1, the first-order natural frequency □, are closer together. As a result, the repulsion coefficient increases, and therefore the carry increases. When compared in terms of carry of a golf ball, the golf club (■) of the present invention has a golf ball distance of approximately 4 m compared to the conventional golf clubs (■) and (2).
, the carry will increase by about 6m.

At present, it is of great interest to players whether or not they can obtain an increase in carry of 1 m, so this value (about 4 m to about 6 m) obtained by the golf club of the present invention has an important meaning. That is, from Table 2, it was confirmed that the golf club of the present invention significantly increased carry.

In the conventional golf club, the mechanical impedance Z showed a first-order minimum value P1 at 2000 Hz or higher, but the golf club of the present invention takes into account the first-order minimum value of the mechanical impedance Z of 21 different golf balls. It is configured to have a first-order minimum value in a relatively low frequency region of 600 Hz to 1600 Hz.

More specifically, regarding the case of a golf club, in FIG. - A plane La that passes through points Qa and Qb that divides b into three equal parts and is perpendicular to the line a-b.

If the club head 8a is divided into three parts by Lb, the center of gravity G of the club head 8a is located near the plane La. That is, the center of gravity G is located approximately 1/3 from the face surface 4, and the ratio of the masses of the three parts is Ml :M2 :M3
=5:3:2. (This mass ratio remains approximately the same as that of the conventional club head.) As shown in FIG. 7, the insert 7 of the face surface 4 is made of a material with a spring constant k that is significantly smaller than that of the conventional club head. Implementation product I of the present invention shown in Table 2 and Figure 1
Then, the spring constant k when compressing the area of diameter 201■
#11,000kg/cm, thickness dimension t”;
Insert 7 of 3 u+, width dimension W''q401 sq., and height dimension H#40 was used.

In this way, by making the spring constant k of the material of the insert 7 sufficiently smaller than that of conventional ABS resin, carbon fiber reinforced resin (CFRP) laminates, or metal plates such as aluminum, it is possible to club having a first-order minimum value P1 at a given frequency within - i.e. 600
Primary natural frequency (resonance frequency) from Hz to 1600Hz
A club having the following properties is obtained. Especially if you do it this way,
There is an advantage that the mass distribution and shape of a conventional golf club can be maintained.

In addition, since mechanical impedance is influenced by the mass distribution of the object, the spring constant, and the damping coefficient, the mass M2. By changing the distribution of the spring constant of M3, changing the mass distribution, or changing various materials and structures, the entire golf club can be configured to exhibit a first-order minimum value within the frequency range of 600 Hz to 1600 Hz. It is possible. It is also preferable to use an engineering plastic such as polycarbonate as the insert 7 and set the spring constant to a national standard so that it exhibits the same first-order minimum value pt.

Further, in the above embodiment, as shown in FIG. 3B, the entire golf club 8 is vibrated to obtain the mechanical impedance of the hitting section 3 that hits the ball, and the first-order minimum value P1 of the mechanical impedance 2 is determined as a predetermined value. However, in addition to this, as shown in FIG. 3F, only the striking part 31, that is, the club head 8a- is vibrated, so that the mechanical impedance 2 is first-order in a predetermined frequency range. It is also desirable to design it so that it exhibits the minimum value P1 of .

Furthermore, the tennis racket 9, baseball bat 100, or bing-bong racket 11 as the ball-hitting tools shown in FIGS. Frequency N at which the mechanical impedance Z of the sphere exhibits the first-order minimum value P1
If b is determined and the mass distribution, spring constant, etc. of the racket 9.10 and bat 10 are appropriately set based on the material, shape, structure, etc. so as to show the first-order minimum value P1 in the frequency range in the vicinity, it will be possible to hit. Immediately after, the initial velocity of the ball increases and the coefficient of repulsion increases.

Specifically, many types of tennis balls, baseball balls,
and the mechanical impedance Z of the bing pong ball as 3rd A
When the present inventor conducted many actual measurement tests at the method company shown in Figures and Figure 4, the frequency Nb□, that is, the first-order natural frequency□ at which the mechanical impedance Z reaches the first-order minimum value P1, was found to be 1.
It has been determined that the frequency is between 10Hz and 500Hz.

Therefore, the entire tennis racket 9 is shown in FIG. 3C.

The mechanical impedance Z when measured as shown in FIG. 4 by vibrating with the vibrator 12 (or by vibrating only the striking surface, although not shown) is in the frequency region 110H.
It is preferable to set the mass distribution, spring constant, etc. of the tennis racket 9 so that the tennis racket 9 has a first-order minimum value P1 in the frequency range of 500 Hz to 500 Hz.

Next, the baseball bat 10 is vibrated by the vibrator 12 as shown in FIG. 3D, and the mechanical impedance Z is measured as shown in FIG. The bat 10 so as to have P1
It is best to set the mass distribution, spring constant, etc.

Furthermore, when the entire ping pong racket 11 is vibrated as shown in Fig. 3E, or only the blade portion 11a is excited as shown in Fig. 3G, and the mechanical impedance Z is measured as shown in Fig. 4, the frequency is Area 110Hz ~ 500H2
The racket l- has a first-order minimum value P1 at
It is preferable to set the mass distribution, spring constant, etc. of 11.

It goes without saying that the present invention includes other sports hitting tools, and is also applicable to (ice) hockey sticks, croquet, and mallets.

〔Effect of the invention〕

The present invention has the following significant effects due to the above-described configuration.

■The ball 2 to be hit and the ball hitting tool 1 that hits it form the best combination, resulting in a large repulsion coefficient, and the ball 2
It can give a large initial speed to the object and fly it far.

■In the past, batting tools were designed based on intuition and experience through repeated trial and error, but according to the present invention,
A ball hitting tool with excellent repulsion performance can now be easily and reliably obtained.

[Brief explanation of drawings]

FIG. 1 shows actual measurement results regarding the golf club of the present invention, two types of conventional golf clubs, and a hit ball.
A characteristic curve diagram showing the change in mechanical impedance with respect to the frequency of vibration applied by the vibrator. FIG. Characteristic curve diagrams showing changes in , Figures 3A to 3G
The figures are simplified explanatory diagrams showing methods of vibrating the whole or the striking part of the ball or various ball-hitting tools using a vibration exciter.
5A to 5D are front views showing various ball hitting tools; FIG. 6 is a diagram showing the case of a golf club as the ball hitting tool; and a diagram for explaining the mass distribution of the club head; FIG. 7 is a perspective view for explaining the configuration of the golf club head. 1... Ball hitting tool, 2... Ball, 3... Hitting section, 8
...Golf club, 8a...Club head, 9...
・Tennis racket, 10...Baseball bat, 11...
Bing Bong racket, 12... Vibrator, Z... Mechanical impedance, D... Frequency domain, N...
Frequency, Pl...first-order minimum value (point). Patent applicant: Sumitomo Rubber Industries, Ltd. FIG.
58 FIG, 5D FIG, 5A FIG, 5C FIG, 6 Procedural amendment October 4, 1985 1.11 Cow's 1985 Patent Application No. 127752 2, Name of invention Batting tool 3, ? Relationship with the witness case Name of patent applicant Name Sumitomo Rubber Industries, Ltd. 4,
8530 Ko (06) 344-0177 Chiyoda Building West Annex 6, 2-5-8 Umeda, Kita-ku, Osaka, Subject of amendment Detailed description of the invention in the specification. 7. Contents of amendment +11 "Figure 2C" on page 9, line 7 of the specification is corrected to "Figure 3C." (2) "Golf club" in line 9 of page 13 of the same book is corrected to "golf ball."

Claims (1)

[Scope of Claims] 1. The mechanical impedance of the hitting part that hits the ball has a first-order minimum value in a frequency region near the frequency at which the mechanical impedance of the ball shows the first-order minimum value. A ball hitting tool. 2. The frequency range is 70% to 130% of the frequency at which the mechanical impedance of the ball exhibits the first minimum value.
%, the ball hitting tool according to claim 1. 3. The frequency range is 80% to 120% of the frequency at which the mechanical impedance of the ball exhibits the first minimum value.
%, the ball hitting tool according to claim 1. 4. The frequency range is 90% to 110% of the frequency at which the mechanical impedance of the ball exhibits the first minimum value.
%, the ball hitting tool according to claim 1. 5. The frequency range is 95% to 105% of the frequency at which the mechanical impedance of the ball exhibits the first minimum value.
%, the ball hitting tool according to claim 1. 6. The ball hitting tool according to claim 1, wherein the frequency at which the mechanical impedance of the hitting portion that hits the ball takes the first minimum value is equal to the frequency at which the mechanical impedance of the ball takes the first minimum value. . 7. The ball hitting tool according to claim 1, wherein the mechanical impedance of the ball and the mechanical impedance of the hitting portion are measured by vibration with a vibrator. 8. The ball hitting tool according to claim 1, wherein the overall shape is a golf club, and the mechanical impedance of the club head for hitting a golf ball has a first-order minimum value in a frequency range of 600 Hz to 1600 Hz. 9. The ball hitting tool according to claim 1, wherein the overall form is a tennis racket, and the mechanical impedance of the hitting surface on which the tennis ball is hit has a first-order minimum value in the frequency range of 110 Hz to 500 Hz. . 2. The ball hitting tool according to claim 1, wherein the entire shape of the ball bat is a baseball bat, and the mechanical impedance of the hitting portion that hits the ball has a first-order minimum value in a frequency range of 110 Hz to 500 Hz. 11. The overall configuration is a ping pong racket, and the mechanical impedance of the hitting surface that hits the ball is:
The ball hitting tool according to claim 1, which has a first-order minimum value in a frequency range of 110 Hz to 500 Hz.