JP2002323403A - Golf ball rotator and measuring device of air force of golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly measure an air force added on a golf ball by reducing deflection of rotation when the golf ball is rotated in a golf ball rotator. SOLUTION: The golf ball rotator is provided with a frame 1, a motor 2 attached to the frame 1, a piano wire 5 penetrated in the golf ball 6 and stretched in the frame 1, and a piano wire holder 10 holding the both ends of the piano wire 5 so that the piano wire 5 provided to the frame 1 becomes rotatable. One of the piano wire holders 10 is directly connected with the motor 2 so that rotating the piano wire 5 with the motor 2 rotates the golf ball 6. The golf ball air force measuring device of this invention is provided with the golf ball rotator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball rotating device for rotating a golf ball at a desired speed and a golf ball air force measuring device for measuring the aerodynamic force applied to a golf ball using the golf ball rotating device. .

[0002]

2. Description of the Related Art To accurately calculate the flight trajectory when an actual golf ball flies while rotating at high speed, it is necessary to give the flight conditions of the ball speed, the number of revolutions, and the direction of the rotation axis to obtain the aerodynamic force. It is necessary to determine the component force (drag coefficient, lift coefficient, lateral force coefficient) and the rotational torque coefficient.

FIG. 14 shows a conventional golf ball rotating device devised for measuring the three-component force of the aerodynamic force and the rotational torque coefficient.

[0004] As shown in FIG. 14, a golf ball rotating device comprises a square frame 1, a motor 2, and a rotating shaft 3a.
To 3d, a piano wire 5, and a golf ball 6.

The rotating shafts 3a, 3b are connected via bevel gears 4c, 4d, and the rotating shafts 3c, 3d are connected via bevel gears 4e, 4f. The rotating shaft 3a and the upper piano wire holding portion are connected via bevel gears 4a and 4b, and the rotating shaft 3d
And the lower piano wire holding unit are connected via bevel gears 4g and 4h.

The piano wire 5 extends vertically and vertically and is inserted into the golf ball 6. Thereby, the golf ball 6 can be held on the frame 1 via the piano wire 5.

In order to rotate the golf ball 6, the motor 2 is operated to rotate the rotating shafts 3a to 3d, and the torque from the rotating shafts 3a to 3d is applied to the upper and lower piano wire holding portions of the piano wire 5. The signal is transmitted through the gears 4a, 4b, 4g, and 4h to rotate the piano wire 5. Thereby, the golf ball 6 can be rotated.

[0008]

As described above, the power from the motor 2 is transmitted to the piano wire holding portions above and below the piano wire 5 so that the piano wire 5 is rotated.
Kinking can be suppressed.

However, the power from the motor 2 is supplied to the rotating shaft 3a.
To 3d and the bevel gears 4a to 4h, the vibration was large and the power transmission loss occurred during power transmission.

Further, as shown in FIG. 15, in the conventional golf ball rotating device, the center of rotation of the piano wire 5 is structurally shifted.

For these reasons, the conventional golf ball rotating apparatus has a problem that when the golf ball 6 is rotated, the rotational fluctuation of the golf ball 6 becomes large. If the rotation deviation of the golf ball 6 is large as described above,
The aerodynamic force applied to the golf ball cannot be measured accurately.

The present invention has been made to solve the above problems. SUMMARY OF THE INVENTION An object of the present invention is to reduce the rotational fluctuation of a golf ball when the golf ball is rotated in a golf ball rotating device, and to accurately measure the aerodynamic force applied to the golf ball.

[0013]

SUMMARY OF THE INVENTION In one aspect, a golf ball rotating device according to the present invention includes a frame, a motor mounted on the frame, a wire inserted through the golf ball and stretched over the frame, and a frame. And first and second holding portions that hold both ends of the wire so that the wire can rotate. Then, the first holding unit is directly connected to the motor,
The golf ball is rotated by rotating the wire rod by the motor.

By directly connecting the first holding portion for holding one end of the wire to the motor in this manner, a power transmission member such as a rotating shaft or a bevel gear for transmitting power from the motor to the wire can be omitted. it can. This can prevent the golf ball from rotating and shaking due to vibration or power transmission loss of the power transmission member when the golf ball is rotated.

A tubular member having an inner diameter substantially equal to the outer diameter of the wire and receiving the wire is installed in the first and second holding portions,
It is preferable that the tension of the wire be 60 N or more and 200 N or less.

The inventor of the present application has made intensive studies on a technique capable of further suppressing the rotational deflection of the golf ball when the wire is directly driven by the motor, and applied the present invention while applying a predetermined tension to the wire as described above. The present inventors have conceived a method of installing a specific tubular member in a holding portion of a wire. By installing a tubular member having an inner diameter substantially equal to the outer diameter of the wire and receiving the wire in the first and second holding portions, for example, as shown in FIG. The deviation can be prevented. In addition, 60N or more 20
By applying a relatively high tension of about 0 N or less to the wire, twisting of the wire can also be suppressed. As a result, the rotational shake of the golf ball can be suppressed.

The golf ball rotating device of the present invention is capable of rotating the golf ball from 0 rotations (preferably 10 rotations) to 15,000 rotations per minute while suppressing the rotational fluctuation of the golf ball by applying the above-described device. Can be.

It is preferable that the golf ball rotating device further includes a tilting mechanism for tilting the frame.

The provision of the tilt mechanism allows the frame to be tilted, and the golf ball can be rotated while the frame is tilted. By blowing wind on the golf ball in this state, a state in which a lateral force acts on the golf ball can be reproduced. Thereby, it is possible to measure the aerodynamic force when a lateral force acts on the golf ball while suppressing the rotational shake of the golf ball.

In another aspect, a golf ball rotating device according to the present invention includes a frame, a wire stretched over the frame and inserted into the golf ball, a motor attached to the frame for rotating the wire, and a frame. And a tilting mechanism for tilting.

By providing the tilt mechanism as described above,
As described above, the aerodynamic force when the lateral force acts can be measured.

The tilting mechanism includes a support shaft that supports the frame so that the frame can be tilted, and a leg that supports the support shaft. By providing such support shafts and legs, the frame can be inclined.

In one aspect, a golf ball aerodynamic measuring device according to the present invention has a golf ball rotating device installed near a wind tunnel opening, a support for supporting the golf ball rotating device, and a blow-out from the wind tunnel opening. And a measuring device for measuring a force applied to the golf ball by the wind. At this time, the golf ball rotation device includes a frame, a motor attached to the frame, a wire stretched over the frame and inserted into the golf ball, and both ends of the wire provided on the frame so that the wire can rotate. The golf ball has first and second holding portions that are directly connected to a motor, and the motor drives the wire rod to rotate the golf ball.

As described above, the golf ball air force measuring device according to the present aspect includes the golf ball rotating device according to the one aspect described above, so that the golf ball air force measuring device can suppress the rotational fluctuation of the golf ball when measuring the air force applied to the golf ball. it can.

In another aspect, a golf ball aerodynamic measuring device according to the present invention is a golf ball rotating device installed near a wind tunnel opening, a supporting portion for supporting the golf ball rotating device, and blown out from the wind tunnel opening. A measuring device for measuring a force applied to the golf ball by the wind. At this time, the golf ball rotating device includes a frame, a wire stretched over the frame and inserted into the golf ball, a motor attached to the frame for rotating and driving the wire, and a tilting mechanism for tilting the frame. Have.

As described above, the golf ball air force measuring device according to the present aspect includes the golf ball rotating device according to the other aspect described above, so that it is also possible to measure the aerodynamic force when a lateral force acts on the golf ball. Can be.

[0027] In any of the above aspects, the support portion includes an air bearing that slidably supports the golf ball rotating device in a direction in which wind is blown out of the wind tunnel opening. Includes a displacement meter for detecting the amount of displacement.

When air is applied to the golf ball by blowing air from the wind tunnel opening, the air bearing slide moves in the direction in which the air force is applied. At this time, by providing a displacement meter such as a laser displacement meter, the displacement of the air bearing slide portion can be detected. Based on this data, the aerodynamic force applied to the golf ball can be measured.

The air bearing preferably has a rotary air bearing between the golf ball rotating device.

By providing the above-mentioned rotary air bearing portion, when a wind is blown out from a wind tunnel opening and an air force is applied to a golf ball, the wind speed and the golf ball rotation speed are changed so that a golf ball rotating device is provided. Can be rotated. By detecting the amount of displacement of the golf ball rotating device at this time with a displacement meter, the rotational (fluid) torque applied to the flying golf ball while rotating at high speed can be measured.

In any of the above aspects, the measuring device may include a load cell for measuring a three-component force (drag coefficient, lift coefficient, lateral force coefficient) of aerodynamic force applied to the wire. Also in this case, the provision of the golf ball rotation device of the present invention enables accurate measurement of the three-component aerodynamic force using the load cell.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of a golf ball rotating device according to one embodiment of the present invention.

As shown in FIG. 1, the golf ball rotating apparatus according to the present invention comprises a frame 1, a motor 2 attached to the frame 1, a piano wire (wire) 5 inserted into a golf ball 6, and a support shaft. 7, an angle adjuster 8, legs 9, and upper and lower piano wire holding portions (attaching portions) 10 provided on the frame 1 and holding both ends of the piano wire 5.

The frame 1 is made of 30 mm aluminum.
And has a square shape of 510 mm on a side, which is made by combining the above square materials. The motor 2 is a DC motor (no-load maximum rotation speed: 15000 rpm), and is mounted at the center of the upper surface of the frame 1.

The piano wire 5 extends vertically in the vertical direction. Both ends of the piano wire 5 are held by a pair of holding portions 10 in the upper and lower directions. The golf ball 6 is rotated by inserting the piano wire 5 into the golf ball 6 and rotating and driving the piano wire 5.

The tension of the piano wire 5 is 60N or more and 200N.
The following may be sufficient. In the present embodiment, the tension of the piano wire 5 is 100N. By applying a relatively high tension to the piano wire 5 in this way, the twisting and lateral vibration of the piano wire 5 can be suppressed. It is also possible to use a wire other than the piano wire 5.

In the piano wire holding section 10, in the embodiment shown in FIG. 1, the end of the piano wire 5 is arranged at a place where the bolt is screwed, and the end of the piano wire 5 is placed between the head of the bolt and the base. The part is sandwiched and fixed. Then, the upper piano wire holding unit 10 is directly connected to the motor 2, and the motor 2 is used to rotate the piano wire 5 together with the piano wire holding unit 10.

By directly connecting the upper piano wire holding portion 10 to the motor 2 in this manner, the power transmission of the rotating shaft, bevel gear, etc., which has been installed in the conventional example for transmitting the power from the motor 2 to the wire rod. The members can be omitted. Thus, when the golf ball 6 is rotated, it is possible to prevent the golf ball 6 from rotating and shaking due to vibration of the power transmission member or power transmission loss.

Further, since the power transmission member can be omitted as described above, the number of components attached to the frame 1 can be reduced, and the weight of the golf ball rotating device can be reduced. Specifically, the weight of the golf ball rotating device can be reduced from 5 kg to 2 kg. Thereby, when measuring the aerodynamic force using the load cell, a load cell having a small rated load can be used, and the measurement accuracy can be improved.

The lower piano wire holding unit 10 holds the piano wire 5
Is held rotatably. Also in the lower piano wire holding unit 10, as in the case of the upper piano wire holding unit 10,
The ends of the piano wire 5 are fixed using bolts.

FIG. 3 is an enlarged view of the piano wire holding unit 10. As shown in FIG. 3, an inner diameter (for example, 0.52 mm) substantially equal to the outer diameter (for example, 0.5 mm) of the piano wire 5 is provided at a lead-out portion (exit portion) of the piano wire 5 in the piano wire holding unit 10.
mm) and a stainless steel double tube (tubular member) 11 for receiving the piano wire 5 is provided. The stainless double tube 11
Is adhered while being inserted into the piano wire holding section 10.

By arranging the stainless steel double tube 11 at the lead-out portion of the piano wire 5 as described above, it is possible to prevent the rotational center of the piano wire 5 from being shifted in structure as shown in FIG. In addition to this, by setting the tension of the piano wire 5 to be relatively high as described above, the rotational shake of the golf ball 6 can be effectively suppressed.

Here, the amount of rotation blur of the golf ball 6 was compared between the conventional golf ball rotating device and the golf ball rotating device of the present invention, and the results are shown in Table 1 below.

[0044]

[Table 1] Table 1 shows the rotational blurring amount of the golf ball 6 obtained by photographing the rotating golf ball 6 with a digital camera and analyzing the photographed image. The photographing site is the insertion hole of the piano wire 5 on the upper surface of the golf ball 6, and the blur amount of the golf ball 6 when the golf ball 6 is stopped and when the rotation speed N = 6000 [rpm] is converted into data by image analysis. .

As shown in Table 1, it can be seen that the golf ball rotating apparatus of the present invention has a smaller rotational shake of the golf ball 6.

Next, the tilting mechanism of the frame 1 in the golf ball rotating device of the present invention will be described.

In the example shown in FIG. 1, the tilting mechanism is provided in a golf ball rotating device of the type in which the piano wire 5 is directly driven to rotate by the motor 2, but the other type of golf ball rotating device is provided with a tilting mechanism. Is also good.

The tilt mechanism shown in FIG. 1 includes a support shaft 7, an angle adjuster 8, and legs 9. In the example shown in FIG. 1, the support shafts 7 are respectively connected to the side portions of the frame 1, and support the frame 1 so that the frame 1 can rotate about the support shaft 7.

The frame 1 can be tilted by rotating the frame 1 around the support shaft 7 by a predetermined angle, and the golf ball 6 is rotated by driving the golf ball 6 in this state. Can be rotated. By blowing the wind on the rotating golf ball 6, it is possible to reproduce a state in which a lateral force acts on the golf ball 6. Thereby, the aerodynamic force when a lateral force acts on the golf ball 6 can be measured.

Although FIG. 1 shows an example in which the frame 1 is rotated clockwise or counterclockwise about the support shaft 7, the frame 1 may be inclined in any direction.

The angle adjuster 8 is attached to one support shaft 7 as shown in FIG. As shown in FIG. 2, the angle adjuster 8 has an angle scale plate 8a and a pointer 8b. The pointer 8 b is attached to the support shaft 7 and rotates together with the support shaft 7.

By rotating the frame 1 about the support shaft 7, the pointer 8b rotates together with the support shaft 7, and the angle of the frame 1 can be known by the angle scale plate 8a.

As shown in FIG. 1, the legs 9 extend downward from the pair of support shafts 7 and support the support shafts 7.

The golf ball rotating apparatus of the present invention having the above-described structure rotates the golf ball 0 times per minute (preferably 10 times) while suppressing the rotational fluctuation of the golf ball 6.
From 15,000 rotations. Of course, it is also possible to rotate at less than 10 revolutions per minute.

Next, a golf ball air force measuring device according to the present invention will be described. FIG. 4 is a schematic diagram showing an example of the golf ball air force measuring device of the present invention.

As shown in FIG. 4, the golf ball aerodynamic measuring device of the present invention is blown out from a wind tunnel device 12, a golf ball rotating device, a support for supporting the golf ball rotating device, and a wind tunnel opening. A measuring device for measuring a force applied to the golf ball by the wind.

The wind tunnel device 12 is a blow-out type wind tunnel. The swirling flow generated by the blower is diffused in the first diffusion section and flows through the corner vane, and sends a stable wind without separation in the second diffusion section. Then, by passing the flow through a rectifying grid or a rectifying wire mesh, a flow having a uniform flow velocity distribution and less turbulence is created.

The turbulence of the wind tunnel is 0.1% or less. The outlet (wind tunnel opening) is a square with a side of 0.4 m, and the measurement unit is an open type. The rotation speed of the blower is 0-226.
By changing to 0 [rpm], the flow rate becomes 0 to 4
It changes up to 4 m / s.

The golf ball rotating device is installed near the wind tunnel opening of the wind tunnel device 12 and has the above structure. Although FIG. 4 shows a golf ball rotating device without a tilting mechanism, the golf ball rotating device may be provided with the above-described tilting mechanism. In this case, the leg 9 of the tilting mechanism may be placed on the support.

The support portion includes an air bearing 14 shown in FIG. 4, on which the golf ball rotating device is mounted.

The air bearing 14 is a slide type air bearing, and an air layer of 5 to 20 μm is interposed between the shaft and the bearing by supplying compressed air. Therefore, since there is no metal contact, there is little deterioration in accuracy and the life is semi-permanent.

The air bearing 14 is used for measuring drag and lift. By changing the direction of the air bearing 14 to a right angle, it can be used for aerodynamic force measurement in two directions one by one.

As shown in FIG. 4, a spring 13 is provided, and the golf ball rotating device is urged by the spring 13 in both positive and negative directions of the pneumatic force to be detected.

The measuring device is a laser displacement meter 15 shown in FIG.
including. More specifically, as shown in FIG.
It includes a laser displacement meter 15, a low-pass filter, and an FFT analyzer.

Table 2 below shows the specifications of the laser displacement meter 15, low-pass filter, and FFT analyzer. Table 3 shows detailed specifications of the laser displacement meter 15.

[0066]

[Table 2]

[0067]

[Table 3] The amount of displacement of the golf ball rotating device is detected by the laser displacement meter 15, and the output voltage from the laser displacement meter 15 is input to an FFT analyzer through a low-pass filter to measure drag and lift. By detecting the amount of displacement of the golf ball rotating device with the laser displacement meter 15 in this manner, errors caused by temperature drift and various disturbances can be reduced.

The aerodynamic three-component force and the rotational (fluid) torque will be described with reference to FIG. As shown in FIG.
The force applied to the golf ball 6 is defined. Wind flow (U)
Is defined as a drag D, a horizontal force against the flow is a lift L, and a vertical force against the flow is a lateral force S. Also,
The torque that reduces the rotation of the golf ball 6 is referred to as the rotation (fluid) torque T.

The flow velocity U [m / s] and the golf ball 6
Is defined as A [m ² ], and the drag D, the lift L, and the rotational torque T are represented by the following aerodynamic coefficients.

[0070]

(Equation 1) Typical dimensionless quantities related to these aerodynamic coefficients are Reynolds number Re = Ud / ν, spin parameter Sp = πNd
/ U, the measurement results are collectively indicated by these dimensionless numbers. Here, ρ is the density of air, ν is the kinematic viscosity coefficient of air, and N [rpm] is the rotation speed of the golf ball 6.
In order to obtain an aerodynamic coefficient in a wide spin parameter range, the flow velocity U is 25 to 44 [m / s] and the rotation speed is 120
It changes between 0 and 12600 [rpm].

Next, a method for measuring the aerodynamic force will be described. A wind having a predetermined flow rate U is blown from the wind tunnel device 12 shown in FIG. As a result, the slide portion of the air bearing on which the golf ball rotating device is mounted moves in the direction in which the air force has acted, and the golf ball rotating device also moves in that direction.

This displacement amount is detected by the laser displacement meter 15, and
The output voltage is calculated by the FFT analyzer, and the drag D
And the lift L was measured. More specifically, the rotation speed N of the golf ball is changed at 1320 to 12600 [rpm], and the air flow speed is changed at U25 to 44 [m / s].
The average was calculated for 8 seconds and the average of 20 times, and the drag D and the lift L were measured.

At this time, by using the above-described golf ball rotating device, the rotational fluctuation of the golf ball 6 can be suppressed in measuring the drag D and the lift L, and the drag D
And the measurement of the lift L can be performed accurately.

The displacement of the golf ball rotating device when a known force is applied to the golf ball 6 with the spring 13 balanced beforehand is measured, and the spring constant in the balanced state is determined. Need to be kept.

When actually measuring the aerodynamic force by setting the golf ball 6 through the piano wire 5 in the golf ball rotating device, the piano wire 5 and the golf ball 6 are present in the wind tunnel airflow. , Pneumatic force acts on both. Therefore, it is impossible to measure the air force acting only on the golf ball 6 due to the structure of the device.

Then, a hole having a diameter of 5 mm is made in the golf ball 6, the golf ball 6 is held by a wire stretched on the wall of the wind tunnel, and only the piano wire 5 is set in the golf ball rotating device so as not to touch the golf ball 6. Then, the aerodynamic force acting only on the piano wire 5 was measured. Then, the air force acting on the golf ball 6 was obtained by subtracting the air force acting only on the piano wire 5 from the measurement result of the air force acting on the golf ball 6 and the piano wire 5.

[0077] change in the lift coefficient C _L with changes in spin parameter Sp 9 shows the (U25~44 [m / s]) , showing the change in drag coefficient C _D with changes in spin parameter Sp 10 .

When the golf ball rotating device has a tilt mechanism for tilting the frame 1, the frame 1
The drag D and the lift L can be measured in a state where is inclined. Thus, the drag D and the lift L when a lateral force acts on the golf ball 6 can be measured.

Note that a load cell may be used instead of the air bearing 14 described above. In this case, the golf ball rotation device of the present invention is installed on the load cell, the number of revolutions N of the golf ball and the flow velocity U of the air are changed, the amount of distortion of the load cell is detected, and converted by a dynamic strain meter. This voltage is passed through a low-pass filter to obtain a time average component,
The drag D and the lift L are measured by an analyzer.

When a load cell is used, the piano wire 5
The air force acting only on the golf ball 6 and the piano wire 5 is measured based on the measurement results of the air force acting on the golf wire 6 and the piano wire 5.
By subtracting the air force acting only on the golf ball 6, the air force acting on the golf ball 6 can be obtained. The load cell may be installed between the air bearing 14 and the golf ball rotating device.

Next, the method for measuring the rotational (fluid) torque of the present invention will be described. FIG. 6 is a schematic diagram of a golf ball aerodynamic measuring device capable of measuring a rotational torque.

In the golf ball air force measuring device shown in FIG. 6, a rotary air bearing 16 is provided between an air bearing 14 and a golf ball rotating device. Other configurations are the same as those of the golf ball aerodynamic measuring device shown in FIG. Here, the rotational (fluid) torque refers to a force that acts to reduce the rotation when the golf ball is actually flying at a high speed while flying.

As shown in FIG. 6, the direction of the golf ball rotating device is balanced by a spring 13 so as to be perpendicular to the direction in which the wind flows. It was changed to cover the parameter range.

When the flow velocity and the number of revolutions of the golf ball are changed, the rotational torque acting on the golf ball 6 causes the golf ball rotating device mounted on the rotary air bearing 16 to rotate. The displacement is detected by the laser displacement meter 15, and the signal is analyzed by the FFT analyzer to measure the rotational torque.

The rotation torque can be measured by the following method. That is, the flow rate is constant (for example, 40
[M / s]) to change the number of revolutions of the golf ball (for example, 2000 to 4000 [rpm]), and affix the reflection mark to the side of the set tack of the upper piano wire 5 and the surface of the golf ball 6. The signal from the optical sensor is analyzed by the FFT analyzer, and the phase difference is calculated from the two pulse time differences.

FIGS. 7 (a) and 7 (b) are views of the golf ball rotating device as viewed from above the piano wire fasteners 17 at the upper part.
The sensor arrangement for detecting the phase difference between the piano wire tacking pin 17 and the golf ball is also shown.

The upper sensor detects the number of rotations of the piano wire tacks 17 and the lower sensor detects the number of rotations of the golf ball.

In the absence of wind, the number of revolutions N of the golf ball is set to 200
The phase difference θ1 shown in FIG. 7 (b) is measured while increasing by 500 [rpm] in the range of 0 to 4000 [rpm]. Then, the wind tunnel velocity U is 40 [m / s], and the golf ball rotation speed N is 500 in the range of 2000 to 4000 [rpm].
[Rpm] and the phase difference (θ
1 + θ2) is measured. This phase difference θ2 is a difference due to the influence of the wind tunnel flow velocity, and the rotational torque is calculated from the phase difference θ2.

In the above-described measurement of the rotational torque, the use of the golf ball rotating apparatus of the present invention can suppress the rotational fluctuation of the golf ball, and can accurately measure the rotational torque. As a result, the change in the number of revolutions during the flight of the golf ball can be known, and accurate trajectory simulation can be performed. FIG. 11 shows an experimental result of the torque coefficient Cm related to the rotation torque T. This torque coefficient Cm changes depending on the value of the spin parameter Sp. Equation 1 shows the relationship between the rotation torque T and the torque coefficient Cm.

Next, the flight trajectory was calculated based on the above measurement results, and the calculated values were compared with the measured values (actually measured values) of the trajectories of the balls hit by the mechanical golfer and the professional golfer. The results will be described.

FIG. 12 shows a comparison result between a calculation value obtained by calculating a flight distance of a two-dimensional flight trajectory based on data measured by using the golf ball rotating apparatus of the present invention and an actually measured value. FIG. 13 shows a comparison result between a calculation value obtained by calculating a flight distance of a two-dimensional flight trajectory based on data measured by a conventional golf ball rotating device and an actually measured value.

A comparison between FIG. 12 and FIG. 13 shows that the measured values obtained using the golf ball rotating apparatus of the present invention are closer to the actually measured values. That is, by using the golf ball rotation device of the present invention, the aerodynamic force acting on the golf ball can be measured more accurately than in the conventional example.

Although there is some variation in FIG. 12, this is data of a professional golfer, and it is presumed that the measurement at this time is different from the golf ball at the time of other measurement. Therefore, it can be seen that the calculated values agree very well with the actually measured values except for the professional data.

Although the embodiments of the present invention have been described above, it should be understood that the embodiments disclosed herein are illustrative in all aspects and not restrictive. The scope of the invention is indicated by the claims,
All changes within the meaning and range equivalent to the claims are included.

[0095]

According to the golf ball rotating device of the present invention, a power transmitting member such as a rotating shaft or a bevel gear, which is installed in the conventional example, for transmitting the power from the motor to the wire can be omitted. Therefore, when the golf ball is rotated, it is possible to prevent the golf ball from rotating and shaking due to the vibration or power transmission loss of the power transmission member, and accurately measure the aerodynamic force applied to the golf ball. be able to.

Further, since the power transmission member can be omitted as described above, the number of components attached to the frame can be reduced, and the weight of the golf ball rotating device can be reduced. Thereby, when measuring the aerodynamic force using the load cell, a load cell having a small rated load can be used, and the measurement accuracy can be improved.

According to the golf ball air force measuring device of the present invention, since the golf ball rotating device is provided, the golf ball can be prevented from rotating and swaying when measuring the aerodynamic force applied to the golf ball. The applied aerodynamic force can be accurately measured. As a result, the flight distance of the flight trajectory of the golf ball can be calculated with high accuracy, and the calculated value can be made closer to the actually measured value.

[Brief description of the drawings]

FIG. 1 is a front view of a golf ball rotating device according to the present invention.

FIG. 2 is an enlarged view of the angle adjuster of FIG.

FIG. 3 is an enlarged view of a piano wire holding portion (drawing portion) of the golf ball rotating device of the present invention.

FIG. 4 is a schematic view of a golf ball air force measuring device according to the present invention.

FIG. 5 is a diagram for explaining the definition of aerodynamic force.

FIG. 6 is a schematic view of another example of the golf ball air force measurement device of the present invention.

FIGS. 7A and 7B are schematic diagrams for explaining a method of measuring a rotational torque.

FIG. 8 is a configuration diagram of a measuring instrument system of the present invention.

9 is a graph showing changes in lift coefficient with a change in the spin parameter Sp C _L.

10 is a diagram showing a change in drag coefficient C _D with changes in spin parameter Sp.

FIG. 11 is a diagram showing a change in a torque coefficient Cm according to a change in a spin parameter Sp.

FIG. 12 is a diagram comparing a flight trajectory calculation result obtained using data obtained by the golf ball aerodynamic measuring device of the present invention with an actually measured value.

FIG. 13 is a diagram comparing a flight trajectory calculation result obtained using data obtained by a conventional golf ball aerodynamic measuring device with an actually measured value.

FIG. 14 is a front view of a conventional golf ball rotating device.

FIG. 15 is an enlarged view of a piano wire holding portion (drawing portion) of a conventional golf ball rotating device.

[Explanation of symbols]

1 frame, 2 motors, 3a-d rotating shafts, 4a-
h Bevel gear, 5 piano wire, 6 golf ball, 7 support shaft, 8 angle adjuster, 8a angle scale plate, 8b pointer, 9 legs, 10 piano wire holding unit, 11 stainless steel double tube, 12 wind tunnel device, 13 Spring, 14 Air bearing, 15 Laser displacement gauge, 16 Rotary air bearing, 17
Piano wire stop tack.

Claims (11)

[Claims] 1. A frame, a motor attached to the frame, a wire stretched over the frame and inserted into a golf ball, and both ends of the wire provided on the frame so that the wire can rotate. A golf ball rotating device comprising: a first and a second holding unit that holds the golf ball; the first holding unit is directly connected to the motor, and the wire is rotated by the motor to rotate the golf ball. 2. A tubular member having an inner diameter substantially equal to the outer diameter of the wire and receiving the wire is installed in the first and second holding portions, and the tension of the wire is set to 60N or more and 200N or less. The golf ball rotation device according to claim 1. 3. The golf ball rotation device according to claim 1, wherein the golf ball is rotated from 0 rotation to 15,000 rotations per minute. 4. The golf ball rotating device according to claim 1, further comprising a tilting mechanism for tilting the frame. 5. A frame, a wire stretched over the frame and inserted into a golf ball, a motor attached to the frame for rotating and driving the wire, and a tilt mechanism for tilting the frame. Equipped,
Golf ball rotation device. 6. The golf ball rotation device according to claim 5, wherein the tilting mechanism includes a support shaft that supports the frame so as to be able to tilt, and a leg that supports the support shaft. 7. A golf ball rotating device installed near a wind tunnel opening, a support for supporting the golf ball rotating device, and a measurement for measuring a force applied to the golf ball by wind blown from the wind tunnel opening. The golf ball rotating device comprises: a frame, a motor attached to the frame, a wire stretched over the frame and inserted into the golf ball, and the wire provided on the frame is rotatable. A first and a second holding portion for holding both ends of the wire so that the first holding portion is directly connected to the motor, and the motor is used to rotate the wire to rotate the golf ball. A golf ball air force measuring device that rotates. 8. A golf ball rotating device installed near a wind tunnel opening, a support for supporting the golf ball rotating device, and a force applied to the golf ball by wind blown from the wind tunnel opening. The golf ball rotating device comprises a frame, a wire stretched over the frame and inserted into the golf ball, a motor attached to the frame for rotating the wire, and the frame. A golf ball aerodynamic measuring device having a tilting mechanism for tilting. 9. The golf ball rotator according to claim 9, wherein the support unit includes an air bearing that slidably supports the golf ball rotator in a direction in which wind is blown from the wind tunnel opening. 9. A displacement meter for detecting a displacement of the vehicle.
2. The golf ball aerodynamic measuring device according to item 1. 10. The golf ball air force measuring device according to claim 9, wherein the air bearing has a rotary air bearing portion between the air bearing and the golf ball rotating device. 11. The golf ball air force measuring device according to claim 7, wherein the measuring device includes a load cell for measuring a three-component force of an aerodynamic force applied to the wire.