JP6152255B2 - Golf club shaft fitting method - Google Patents

Description

  The present invention relates to a method for fitting a shaft of a golf club.

  It is an eternal theme for golfers to extend the distance of the ball and to fly it in the direction and angle aimed at. To that end, it is important to use a golf club that fits your swing.

  Selecting a golf club suitable for a golfer is generally referred to as fitting. In order to perform this fitting effectively, it is necessary to consider various factors such as the total weight of the golf club, the weight of the club head, and the length of the golf club. It greatly affects the quality.

  In conventional golf club shaft fittings, many methods have been proposed mainly focusing on the bending rigidity of the shaft, but there are not so many methods focusing on the torsional rigidity (torque) of the shaft.

  However, during a golf swing, it is true that the shaft bends due to the swing, but due to the fact that the center of gravity of the head is offset from the shaft axis and the golfer's wrist moves during the swing, Twisting motion is occurring at the same time as the bending. This twisting motion is also greatly related to the flying distance of the hit ball, the directionality, and the ease of swinging of the golf club, and particularly the directionality and ease of swinging are greatly influenced by the torsional rigidity of the shaft.

  With regard to the torque of the shaft, in the conventional methods, the torque was determined empirically from the head speed at impact and the apparent swing tempo, but these methods are based on the experience and intuition of the fitting person (fitter). There are many problems to be relied upon, and the result of the selection is not objective but causes individual differences.

  On the other hand, a technique has been proposed in which a golf club equipped with a sensor is swung by a user, and a golf club is designed and selected using the obtained sensor data (see, for example, Patent Document 1).

  In the golf club designing apparatus / program described in Patent Document 1, the bending and torsional rigidity of the shaft is defined using sensor data, and a swing response curved surface obtained by functionalizing the user's skill is calculated from the sensor data. The movement of the golf club grip obtained by the swing response curved surface is given as displacement data, and the movement of the club head is calculated.

JP 2011-425 A

  However, the method described in Patent Document 1 has a problem that it is difficult to define the torsional rigidity because the integration error is piled up when calculating the displacement from the acceleration and the angular velocity, and the displacement cannot be calculated with high accuracy. is there. Furthermore, in the method described in Patent Document 1, a method for defining the torsional rigidity is not specifically defined.

  The present invention has been made in view of such circumstances, and provides a golf club shaft fitting method capable of accurately and objectively fitting a shaft having a torque matched to a golfer's swing. It is aimed.

(1) A golf club shaft fitting method according to the present invention (hereinafter also simply referred to as “fitting method”) selects a shaft having a torque that matches the golfer based on the golfer's swing. A fitting method,
Hitting a golf ball with a golf club in which a sensor capable of measuring angular velocities around three axes is attached to the grip to obtain a measurement value of the sensor;
Obtaining a predetermined index value for the angular velocity quantified from the measured value;
Selecting a shaft that matches the golfer from a plurality of shafts that have been measured in advance based on the relationship between the index value and the torque of the shaft that has been created in advance by trial striking. .

  In the fitting method of the present invention, an index value is obtained by quantifying the grip angular velocity measured by a sensor attached to the grip, and this index value and the relationship between the index value and the shaft torque created in advance by trial hitting are obtained. Based on the above, a shaft that matches the golfer is selected from a plurality of shafts whose torque has been measured in advance. Therefore, a shaft having a torque matching the golfer's swing can be objectively fitted with high accuracy, and as a result, the flight distance, directionality and ease of swinging of the hit ball can be improved.

(2) In the fitting method of (1), the sensor is preferably attached to a grip end.

(3) In the fitting method of (1) or (2), the x-axis is oriented along the toe heel direction of the golf club head, the y-axis is oriented along the hitting direction, and the z-axis is the shaft axis. When oriented to match the direction,
Determining an address, top and impact in the swing from the measured values;
Calculating _{t_ωy_max} to _imp , which is the time from when the y-axis grip angular velocity is maximized to the impact during the _downswing ,
Calculating ωx_ωy_max to _imp , which is an average value of grip angular velocities about the x-axis from when the grip angular velocity becomes maximum to impact.
The calculated ωx_ωy_max˜imp is _divided by _{t_ωy_max˜imp} to calculate the magnitude of the change amount of the grip angular velocity per unit time around the x-axis as the index value, and prepared in advance by trial hitting. The torque is calculated from the calculated magnitude of the change amount of the grip angular velocity per unit time around the x axis using an approximate expression showing the relationship between the magnitude of the change amount of the grip angular velocity around the x axis and the torque of the shaft. It may include a calculating step.

(4) In the fitting method (3), as the approximate expression used in the step of calculating the torque, prepared according to the magnitude of the Omegazui_ _top is a variation of the grip angular velocity about the z-axis near the top One of a plurality of approximate expressions may be used.

(5) In the fitting method (4), the plurality of approximate expression, the Omegazui_ _top with the 20 (deg / s) or more first approximation formula when, if less than 20 (deg / s) A second approximate expression may be used for

(6) In the fitting method of (1) or (2), the x-axis is oriented along the toe heel direction of the golf club head, the y-axis is oriented along the hitting direction, and the z-axis is the shaft axis. When oriented to match the direction,
Determining an address, top and impact in the swing from the measured values;
As the index value, step calculates the Omegazui_ _top is a variation of the grip angular velocity about the z-axis in the vicinity of the top, and were prepared in advance by test shot, variation of the z-axis of the grip angular velocity and the torque of the shaft Using the approximate expression indicating the relationship, a step of calculating torque from the calculated change amount of the grip angular velocity about the z-axis can be included.

(7) In the fitting method of (6), as the approximate expression used in the step of calculating the torque, the approximate expression used around the z axis until the grip angular velocity of the y axis becomes maximum during the downswing from the top. Using one of multiple approximate formulas prepared according to the amount of change in grip angular velocity,
The amount of change in the grip angular velocity around the z-axis is ωz_top to _{ωy_max} , which is an average value of the grip angular velocity around the z-axis until the grip angular velocity on the y-axis reaches the maximum during the downswing from the _top . Also, it may be a value divided by _{t_top} to _{ωy_max} , which is the time from the top to the time when the y-axis grip angular velocity is maximum during the _downswing .

(8) In the fitting method (7), among the plurality of approximate expression, the a value obtained by dividing _{ωz_} top~ωy_max / _{t_} top~ωy_max is -500 (deg / ^{s 2)} third in the following cases The approximate expression may be used, and the fourth approximate expression may be used when greater than −500 (deg / s ² ).

  According to the fitting method of the present invention, it is possible to objectively fit a shaft having a torque matching a golfer's swing with high accuracy, and as a result, it is possible to improve the flight distance, directionality and ease of swinging of the hit ball. it can.

It is a figure explaining the method to measure the grip angular velocity in this invention. It is a partially expanded perspective view of a golf club to which a sensor is attached. (A) is a top view of the sensor shown by FIG. 2, (b) is a side view of the sensor. It is a figure which shows the address and takeback in a swing. It is a figure which shows the top and downswing in a swing. It is a figure which shows the downswing and impact in a swing. It is a figure which shows the follow through and finish in a swing. It is a figure which shows an example of the change according to the time passage of the angular velocity of the x-axis direction in a swing. It is a figure which shows an example of the change along the time passage of the angular velocity of the y-axis direction in a swing. It is a figure which shows an example of the change along the time passage of the angular velocity of the z-axis direction in a swing. It is a figure explaining the method of measuring the torque of a shaft. It is a figure which shows the example of a relationship between the shaft torque with favorable directionality, and the index value in this invention, Comprising: It is a figure which is not stratified. It is a figure which shows the example of a relationship between the shaft torque with favorable directionality, and the index value in this invention, Comprising: Data is the figure stratified. It is a figure which shows the example of a relationship between the shaft torque which is easy to swing, and the index value in this invention, Comprising: It is a figure which is not stratified of data. It is a figure which shows the example of a relationship between the shaft torque which is easy to swing, and the index value in this invention, Comprising: Data is the figure stratified.

Hereinafter, embodiments of the fitting method of the present invention will be described in detail with reference to the accompanying drawings.
In the fitting method of the present invention, a golf club having a sensor capable of measuring angular velocities in three axial directions is caused to swing by a golfer, and the obtained angular velocities are determined according to the swing section or time zone (for example, the y-axis (cock direction)). The golf club shaft having a torque matched to the golfer is selected based on the index value derived using the value quantified by the time from the time when the grip angular velocity of the golf ball reaches the maximum to the time of impact.

  In the present invention, as shown in FIG. 1, a golfer who wants to fit a golf club actually swings, and from the swing, an “index value” unique to the golfer is calculated. A sensor 2 capable of measuring angular velocities around three axes is attached to the grip end of the golf club 1 via an adapter 3 as shown in FIGS. The sensor 2 includes a casing 2a made of a box having a square shape in plan view. The casing 2a can be fixed to the grip end by double-sided tape, adhesive, screwing, or the like. In the example shown in FIG. 1, the golfer G is right-handed and is in an address state immediately before starting a swing for hitting the ball B set at a predetermined position.

In order to improve the fitting accuracy, if the length of the user's My Club is different from the length of the golf club based on the shaft stored in the database, the total club weight equivalent to the club length prepared in the database By changing to, a shaft that matches the user can be selected. For example, if the length of a club stored in the database is 45 inches and the user's club length A (mm) is different from 45 inches (= 1143 mm), the total weight of the club swinging for measurement is calculated. The fitting is performed by changing to the one calculated by the following formula (total weight corresponding to 45 inches).
(Total club weight used for measurement) = (A-1143) × 0.377 + (total club weight of my club)

  The sensor 2 is wireless, and the measured data is transmitted wirelessly to a wireless reception device (not shown) built in the computer 10 as a data analysis device. As the wireless communication, for example, Bluetooth (Bluetooth (Bluetooth is a registered trademark)) standard and technology can be used.

  The sensor 2 incorporates an angular velocity sensor (not shown) that can measure angular velocities about three axis directions (x-axis direction, y-axis direction, and z-axis direction). The sensor 2 further includes an A / D converter, a CPU, a wireless interface, a wireless antenna, and a power source. As the power source, for example, a button-type lithium ion battery or the like can be used. The battery may be rechargeable. The sensor 2 may include a charging circuit for charging the battery. An example of the sensor 2 that can be used is WAA-010 (trade name) manufactured by Wireless Technology.

  The wireless receiving device that receives a signal from the sensor 2 includes a wireless antenna, a wireless interface, a CPU, and a network interface.

  A computer 10 serving as a data analysis apparatus includes an input unit 6 including a keyboard 4 and a mouse 5 and a display unit 7. Although not shown, the computer 10 includes a hard disk, a memory, a CPU, and a network interface.

  The sensor 2 detects angular velocities around the x-axis, y-axis, and z-axis. These angular velocities are obtained as analog signals, and the analog signals are converted into digital signals by an A / D converter built in the sensor 2. The output from the A / D converter is transmitted to the CPU, and arithmetic processing such as primary filtering is executed. The data thus processed in the sensor 2 is transmitted from the wireless antenna to the wireless reception device built in the computer 10 via the wireless interface.

  The data transmitted from the sensor 2 is received by the wireless interface via the wireless antenna on the wireless receiving device side. The received data is processed by the CPU of the computer 10.

  Data sent to the computer 10 is recorded in a memory resource such as a hard disk. The hard disk stores programs and data necessary for data processing and the like. This program causes the CPU to execute necessary data processing. The CPU can execute various arithmetic processes, and the calculation results are output by the display unit 7 or a printing device (not shown).

  When the sensor 2 is attached to the grip end, the relationship between the measurement axis and the golf club 1 is considered. In the present embodiment, the z axis of the sensor 2 coincides with the shaft axis of the golf club 1. The x axis of the sensor 2 is oriented along the toe heel direction of the head 1 a of the golf club 1. In addition, the y-axis of the sensor 2 is oriented along the hitting direction. By attaching the sensor 2 in this way, the calculation can be simplified.

  In this embodiment, a local coordinate system is considered, and the x-axis, y-axis, and z-axis of this local coordinate system are a three-dimensional orthogonal coordinate system. In the present embodiment, the z axis is the shaft axis of the golf club 1, and the x axis is oriented along the toe heel direction of the head 1a. Further, the y-axis is oriented along the hitting direction.

  That is, the z axis of the local coordinate system matches the z axis of the sensor 2, and the y axis of the local coordinate system matches the y axis of the sensor 2. Further, the x-axis of the local coordinate system matches the x-axis of the sensor 2.

  The sensor 2 can obtain a plurality of continuous data in time series. The number of data per unit time depends on the sampling frequency.

  4 to 7 are diagrams for explaining the swing from the address to the finish by the golfer. The swing includes a fall-through after impact. In the present invention, attention is paid to the characteristics of the swing from address to impact.

  4-7 is the figure which looked at the golfer from the front. The beginning of the swing is the address, and the end of the swing is called the finish. The swing proceeds in the order of (S1), (S2), (S3), (S4), (S5), (S6), (S7), and (S8). In FIG. 4, (S1) is an address, and (S2) is a takeback. (S3) in FIG. 5 is the top (top of swing). Usually, at the top, the moving speed of the head during the swing is minimum. (S4) in FIG. 5 is a downswing. Although (S5) in FIG. 6 is also a downswing, the downswing is more advanced than (S4) in FIG. 6 (S6) is an impact, which is the moment when the head 1a of the golf club 1 and the ball B collide. In FIG. 7, (S7) is a follow-through, and (S8) is a finish. At the finish, the swing ends.

FIG. 8 is a diagram showing the relationship between the time (s) from the address to the impact in a certain swing and the angular velocity ωx (deg / s) in the x-axis direction, and FIG. 9 is also the time from the address to the impact ( s) and the angular velocity ωy (deg / s) in the y-axis direction. FIG. 10 shows the time (s) from the address to the impact and the angular velocity ωz (deg / s) in the z-axis direction. It is a figure which shows the relationship. 8 to 10, time points A to D indicate the swing start time, the top of the swing, the time when the grip angular velocity in the y-axis (cock) direction is maximized, and the impact in the swing, respectively. In this embodiment, as shown in FIGS. 8 to 10, a predetermined index value is set with the lapse of time of swing, and each index value is obtained by quantifying the grip angular velocity. For example, the fixed value (7) in FIG. 8 is ωx_ωy_max to _imp , which is an average value of grip angular velocities around the x axis from when the y-axis grip angular velocities are maximized during the _downswing . Also, the quantitative value (9) in FIG. 10 is ωz_top, which is the amount of change in the grip angular velocity around the z axis near the _top . Also, the quantitative value (10) in FIG. 10 is ωz_top to _{ωy_max} , which is an average value of grip angular velocities around the z axis until the grip angular velocities on the y axis reach the maximum during the downswing from the top.

  FIG. 11 is a diagram illustrating a method for measuring the torque of the shaft 11 of the golf club 1. In this measuring method, the rear end portion of the shaft 11 is fixed to be non-rotatable by the jig M1, and the front end portion of the shaft 11 is held by the jig M2, and 13.9 kgf · cm is positioned 40 mm from the tip end Tp. Torque Tr is applied. The torsion angle (degree) of the shaft 11 at this torque acting position is the shaft torque value. The rotational speed of the jig M2 when applying the torque Tr is 130 degrees / min or less, and the axial length between the jig M1 and the jig M2 is 825 mm. Furthermore, when the shaft 11 is deformed by gripping the jig M1 or the jig M2, the core 11 is filled in the shaft 11 and measurement is performed.

(Indicator value)
In the present embodiment, attention is paid to the grip angular velocity during the downswing from the vicinity of the top to the impact among the various stages in the swing described above, and the angular velocity is subdivided and quantified as time passes. Then, the shaft of the golf club is selected based on the index value calculated using the quantified value (quantitative value) and the relationship between the torque matched to the golfer and the index value that has been obtained in advance by trial hitting. . In the present specification, “near the top” means a time period including a predetermined time immediately before the top and a predetermined time immediately after the top. Specifically, for example, 100 ms from the top −50 ms to the top +50 ms. Means the time zone.

  The “index value” in the present invention is a value calculated by quantifying the grip angular velocity, and is a value in which a correlation with the torque matched to the golfer is recognized. For example, the following values are exemplified. be able to. Matching with a golfer means that it is objectively evaluated by the standard deviation σ of the variation in the right and left of the hit ball, such as the direction of the hit ball, and a golfer's sensory test (listening survey), such as the ease of swinging the club. ) May be evaluated.

(1) Index value (A): The magnitude of the amount of change in grip angular velocity per unit time around the x axis from when the y-axis grip angular velocity is maximized to the impact. This index value (A) is especially the direction of the hit ball It is a value that shows a correlation with the torque matched to the golfer in the sense of improving the performance. The directionality of the hit ball is determined by the orientation of the face immediately before the impact, but this face angle has a high correlation with the amount of change in the grip angular velocity around the x axis immediately before the impact. That is, as the amount of change in angular velocity about the x-axis immediately before impact is larger, the head is accelerated more rapidly, so that the face direction is likely to be disturbed and easily opened at the moment of impact. When a shaft with a small torque is selected for such a golfer, the variation in face angle is reduced and the opening of the face is suppressed, so that the direction of the hit ball is improved. Similarly, in the opposite case, if the amount of change in angular velocity about the x-axis immediately before impact is small, the face cannot be opened by itself and the ball is likely to be caught, and the directionality of the hit ball is deteriorated. If the face cannot be opened, the loft angle at the time of impact is insufficient and the flight distance is insufficient. When a shaft having a large torque is selected for such a golfer, the face is appropriately opened to improve the directionality of the hit ball, and an appropriate loft angle can be obtained to increase the flight distance.

The index value (A) is calculated as follows.
First, from the waveform of the grip angular velocity ωy around the y-axis, _{t_ωy_max} to _imp , which is the time (t1) from when the y-axis grip angular velocity reaches its maximum during the _downswing, is calculated.
Next, ωx_ωy_max to _imp , which is an average value (m1) of grip angular velocities around the x axis from when the y-axis grip angular velocities become maximum during the downswing to the _impact, is calculated.

Next, by dividing the average value (m1) by the time (t1), the magnitude of the change in grip angular velocity per unit time around the x axis from when the y-axis grip angular velocity becomes maximum to the impact is obtained. A certain index value (A) is obtained.
Index value (A) = ωx_ωy_max to _imp / _{t_ωy_max to imp}
Based on the index value (A) calculated in this way and the relationship between the index value (A) and the torque that matches the golfer with respect to the directionality of the hit ball, which was previously determined by trial hit, Torque is calculated based on an approximate expression that represents the relationship.
For example, when ωx_ωy_max to _imp / _{t_ωy_max} to _imp is x, the following expression (1) representing a regression line obtained by the least square method can be used as an approximate expression.
Torque (deg) = − 0.0000547x + 5.17 (1)

(2) Index value (B): Amount of change in grip angular velocity around the z-axis near the top Approximate expression representing the relationship between the torque matching the golfer and the index value (A) with respect to the directionality of the hit ball (for example, the above formula (1)) can be used to calculate the torque, but in order to improve the directionality, the index value (B) is used to stratify the relationship between the torque and the index value (A). can do.

Ωz_top, which is the amount of change in the grip angular velocity around the z-axis near the _top, is positive when the face is closed. This ωz_ _top positive golfers, right hand at the top is swung down a golf club overlaying. The face is easy to close when covered by the right hand, so if you use a shaft with a small torque, the face will not open during the downswing, and the ball will be caught by impact, or you will use too much wrist and try to open the ball. The directionality deteriorates due to the appearance of sliced balls and sliced spheres. Therefore, Omegazui_ _top positive golfer, is better to select the shaft torque is larger preferable.

On the other hand, the golfer Omegazui_ _top is negative or small, the face is in the direction of opening, as either face to impact open, the use of large shaft torque, wrist hated too open face in the downswing It closes and hooks and hook balls are likely to come out. Therefore, a golfer Omegazui_ _top is negative or small, it is preferable to select a shaft torque is small.

Thus, the stratified relationship between the torque and the index value (A) according to the size of Omegazui_ _top, it is preferable to use a suitable one approximation formula from a plurality of approximate expression prepared in advance.
For example, ωx_ _{ωy_max~imp} / When the t_ _{Omegawai_max～imp} and x, ωz_ _top 20 in the case of more than (deg), the following equation (2) an approximate expression representing the regression line obtained by the least squares method (first approximate expression) and, ωz_ _top can be 20 (in the case of less than deg), also the following equation (3) the approximate expression (second approximate expression).
Torque (deg) = − 0.0000571x + 5.45 (2)
Torque (deg) = − 0.0000571x + 4.70 (3)

  The index value (B) can be used for stratification when calculating the torque using the index value (A), but the index value (B) itself means that it improves the ease of swinging. This value is correlated with the torque matched to the golfer. Therefore, torque can also be calculated using this index value (B).

The ease of swinging a golf club is the ease of timing, and it is considered that the golf club feels easy to swing when the swing and shaft twisting are synchronized. In the present invention, various tests (trial hits) were performed, and the ease of swinging was scored by a questionnaire and the correlation with the swing index value was confirmed. As a result, the golf club swingability was about the z axis near the top. correlation between Omegazui_ _top is a variation of the grip angular velocity is found to be high. That is, a phenomenon similar to the stratification of fitting focusing on the directionality described above occurs, and it is considered that the index value (B) is connected to the timing of impact.

Therefore, based on the index value (B) and the relationship between the index value (B) and the torque that matches the golfer with respect to the ease of swinging the golf club, which has been obtained in advance by trial hitting, specifically, the relationship between the two is obtained. Torque can be calculated based on the approximate expression that it represents.
For example, if the Omegazui_ _top to x, the following expression for the regression line obtained by the least squares method (4) can be approximate expression.
Torque (deg) = 0.00939x + 3.38 (4)

(3) Index value (C): The amount of change in the grip angular velocity around the z-axis until the maximum grip angular velocity on the y-axis is in the middle of the downswing from the top. The torque can be calculated by using an approximate expression (for example, the expression (4)) representing the relationship between the torque to be performed and the index value (B), but this index value ( C) can be used to stratify the relationship between the torque and the index value (B).

The index value (C) can be calculated as follows.
First, from the waveform of the grip angular velocity ωy in the y-axis direction, _{t_top} to _{ωy_max} , which is the time (t2) from the top to the time when the grip angular velocity of the y-axis becomes maximum during the _downswing, is calculated.
Next, ωz_top to _{ωy_max} , which is an average value (m2) of grip angular velocities around the z axis until the grip angular velocities on the y axis reach the maximum during the downswing from the _top, is calculated.

Next, by dividing the average value (m2) by the time (t2), the amount of change in the grip angular velocity around the z axis until the grip angular velocity on the y axis reaches the maximum during the downswing from the top. The index value (C) that is the height is obtained.
Index value (C) = _{ωz_top˜ωy_max} / _{t_top˜ωy_max}

A golfer with a large index value (C) has a large amount of shaft twist change (in the direction in which the face opens) at the beginning of the downswing. In particular, when the negative absolute value is large, the face is opened by itself. Therefore, if a shaft having a large torque is used, the face is opened too much or the variation becomes large, the timing is difficult to obtain, and the feeling deteriorates. Therefore, it is preferable that a golfer with a large index value (C) selects a shaft with a small torque.

  On the other hand, a golfer with a small index value (C), that is, a small amount of change in angular velocity, hardly opens and closes the face himself. Therefore, when a shaft with a small torque is used, the rotation of the face does not occur and the shaft feels hard. . Therefore, it is preferable that a golfer with a small index value (C) selects a shaft with a large torque.

As described above, the relationship between the torque and the index value (B) is _stratified according to the magnitude of ωz_top to _{ωy_max} / t_top to _{ωy_max} , and one suitable approximation from a plurality of prepared approximate expressions It is preferable to use the formula.
For example, when the Omegazui_ _top and x, when _{ωz_} top~ωy_max / _{t_} top~ωy_max is -500 (deg) or less, an approximate expression of the following expression for the regression line obtained by the least squares method (5) (a 3 approximate expression), and is greater than _{ωz_} top~ωy_max / _{t_} top~ωy_max is -500 (deg), it is possible to similarly following equation (6) the approximate expression (4 approximate expression).
Torque (deg) = 0.9991x + 3.50 (5)
Torque (deg) = 0.9991x + 2.90 (6)

[How to obtain approximate expression]
The approximate expression can be obtained as follows, for example.
Twenty right-handed men with handicap of 2 to 20 were prepared as testers. As a golf club, SRIXON Z-TX2 (club length: 45.0 inches, loft angle: 9.5 degrees) manufactured by Dunlop Sports Co., Ltd. was used. As shown in Table 1, three types of flexes (equivalent to X / S / R) are prepared as shafts, and torques of 3.0, 3.5, 4.0, 4.5 and 5. Five types of 0 were prepared. The head and shaft are detachable, and each tester made a test shot using the same head throughout the test. A tester with a high trajectory used a head with a loft standing, and a tester with a low trajectory used a head with a loft sleeping.

The grip angular velocity was measured by the measurement method described with reference to FIG. Using a SRIXON Z-STAR XV manufactured by Dunlop Sports Co., Ltd. as a ball, a total of 25 trials were made for each club (shaft), 5 balls each. However, the obvious miss shots were excluded and reworked.
The directionality was evaluated by the standard deviation σ of the left-right variation of the hit ball, and the shaft having the smallest σ was determined as the shaft with good directionality. Further, the ease of swinging was determined by interviewing each tester with the shaft that was most likely to swing after trial-fitting five balls for each of the five types of shafts. The results are shown in Table 2.

  The index values (A) to (C) described above were calculated using the measured grip angular velocity data. Tables 3 to 4 show the calculation results and the most directional shaft torque evaluated by the standard deviation σ of the left-right variation of the hit ball. Similarly, Tables 5 to 6 show the calculation results and the shaft torques determined most easily by the interview survey. Tables 3-6 correspond to FIGS. 12-15, respectively.

  Table 3 (FIG. 12) and Table 5 (FIG. 14) are not stratified by other index values, and Table 4 (FIG. 13) and Table 6 (FIG. 15) are layers by other index values. Separated. Table 4 (FIG. 13) is stratified according to whether the index value (B) is 20 or more and less than 20. Table 6 (FIG. 15) is stratified according to whether the index value (C) is −500 or less and greater than −500.

1 Golf Club 2 Sensor 10 Computer 11 Shaft B Ball G Golfer

Claims (6)

A method for fitting a shaft of a golf club, which selects a shaft having a torque matching the golfer based on a golfer's swing,
Hitting a golf ball with a golf club in which a sensor capable of measuring angular velocities around three axes is attached to the grip to obtain a measurement value of the sensor;
Obtaining a predetermined index value for the angular velocity quantified from the measured value;
Pre created by test shot, based on a relationship between the torque of the index value and the shaft, it viewed including the step of selecting the matching shaft golfer from among a plurality of shafts advance torque is measured,
When the x-axis is oriented in the direction along the toe heel direction of the golf club head, the y-axis is oriented along the hitting ball direction, and the z-axis is oriented so as to coincide with the axial direction of the shaft,
Determining an address, top and impact in the swing from the measured values;
Calculating _{t_ωy_max} to _imp , which is the time from when the y-axis grip angular velocity is maximized to the impact during the _downswing ,
Calculating ωx_ωy_max to _imp , which is an average value of grip angular velocities about the x-axis from when the grip angular velocity becomes maximum to impact .
Dividing the calculated ωx_ωy_max˜imp by _{t_ωy_max˜imp} to calculate a value _obtained by dividing the average value of the grip angular velocity around the x-axis by the time as the index value; and
The approximate value of the grip angular velocity about the x axis calculated in advance is calculated using an approximate expression showing the relationship between the average value of the grip angular velocity about the x axis divided by the time and the torque of the shaft. Calculating torque from a value obtained by dividing the average value by the time
The characterized by including Mukoto, of the golf club shaft of the fitting method.   The golf club shaft fitting method according to claim 1, wherein the sensor is attached to a grip end. As the approximate expression used in the step of calculating the torque, one of a plurality of approximate expression is prepared in accordance with the size of the Omegazui_ _top is a variation of the grip angular velocity about the z-axis near the top The method for fitting a shaft of a golf club according to claim 1, which is used. Among the plurality of approximate expression, the first approximation formula used in the case of the Omegazui_ _top is 20 (deg / s) or more, using 20 (deg / s) less than the second approximation formula in the case of, in claim 3 A method for fitting a shaft of the described golf club. A method for fitting a shaft of a golf club, which selects a shaft having a torque matching the golfer based on a golfer's swing,
Hitting a golf ball with a golf club in which a sensor capable of measuring angular velocities around three axes is attached to the grip to obtain a measurement value of the sensor;
Obtaining a predetermined index value for the angular velocity quantified from the measured value;
A step of selecting a shaft that matches a golfer from a plurality of shafts that have been measured in advance based on a relationship between the index value and the torque of the shaft, which is created in advance by trial hitting;
Including
When the x-axis is oriented in the direction along the toe heel direction of the golf club head, the y-axis is oriented along the hitting ball direction, and the z-axis is oriented so as to coincide with the axial direction of the shaft,
Determining an address, top and impact in the swing from the measured values;
As the index value, step calculates the Omegazui_ _top is a variation of the grip angular velocity about the z-axis in the vicinity of the top, and were prepared in advance by test shot, variation of the z-axis of the grip angular velocity and the torque of the shaft using the approximate expression indicating the relationship, it viewed including the step of calculating a torque from the change amount of the calculated z-axis of the grip angular velocity,
As the approximate expression used in the step of calculating the torque, ωz_top to _{ωy_max,} which is an average value of grip angular velocities around the z-axis from the top to the time when the grip angular velocities on the y-axis become maximum during the _downswing. One of a plurality of approximate expressions prepared according to a value divided by _{t_top} to _{ωy_max} , which is the time until the grip angular velocity of the y axis reaches the maximum during the downswing from the top, is used A method for fitting a shaft of a golf club, comprising: Wherein the plurality of approximate equations, the third approximate expression used in the case the a value obtained by dividing _{ωz_} top~ωy_max / _{t_} top~ωy_max is -500 (deg / ^{s 2)} or less, -500 (deg / ^{s 2} The method of fitting a shaft of a golf club according to claim 5 , wherein the fourth approximate expression is used when the value is larger.

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