Rigidity characteristic measuring method and rigidity characteristic measuring device

Abstract

The rigidity characteristic measuring device (10) holds the golf club head (30) in a manner that the club face (32) faces upward, causes the collision rod (24) to fall in a vertical direction toward the club face (32), and calculates the rigidity characteristic of the golf club head (30) based on the detection value of the acceleration sensor (26) installed on the collision rod (24). A falling distance changing step is implemented, and each time a measuring position on the club face (32) is changed, the falling distance of the collision rod (24) is adjusted in a manner that the collision speed of the collision rod (24) toward the measuring position is approximately constant.

Description

Technical Field

[0001] The present invention relates to a rigidity characteristic measuring method and a rigidity characteristic measuring device for measuring the rigidity characteristic of a collision object. Background Art

[0002] Conventionally, there is known a technique for measuring rigidity characteristics such as a CT (Characteristic Time) value and a rebound coefficient, which are indices that affect the rebound performance of a hitting tool such as a golf club head.

[0003] In particular, in competitive golf clubs, the CT value measured by the pendulum tester specified by the USGA (United States Golf Association) is used as a reference value for evaluating rigidity characteristics. The pendulum test procedure and the like are described in detail in the following non-patent document 1.

[0004] Patent Document 1 below is a device for implementing the pendulum test, in which a golf club with a club head and a shaft as one is fixed and a metallic sphere is made to collide with the club face by a pendulum. An acceleration sensor is mounted on the sphere, and a parameter representing the rigidity characteristic is calculated based on the detection value thereof.

[0005] In addition, the following patent document 2 is a rigidity characteristic measuring device for measuring the rigidity characteristics of a golf club head (collision body), which comprises: a club head fixing clamp for holding the golf club head in a manner such that the club face is facing upward; a linear bushing for causing the collision rod (collision body) to fall toward the golf club head in a vertical direction; the collision rod equipped with an acceleration sensor; and a computer for calculating the rigidity characteristics of the golf club head, such as a CT value, based on the detection value of the acceleration sensor.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: U.S. Patent No. 6837094

[0009] Patent Document 2: International Publication No. 2019 / 030973

[0010] Non-patent literature

[0011] Non-Patent Document 1: “Technical Description of the Pendulum Test (Revised Version)”, The Royal and Ancient Golf Club of St Andrews and United States Golf Association, November 2003 Summary of the invention

[0012] Problem that the invention aims to solve

[0013] In the above-mentioned Patent Document 1, the test is based on the premise of using a club shape in which the club head and the shaft are integrated, and the test needs to be carried out while the shaft is held. Therefore, when measuring for quality control in the manufacturing process of the club head, the process of assembling the shaft is required, which is complicated.

[0014] In addition, the shaft is cylindrical and therefore easily rotates in the circumferential direction, and it is difficult to set the collision angle with the collision body to be constant during the test. In addition, the rigidity characteristics may change due to the influence of the natural vibration of the shaft from the material of the shaft, the clamping position, the clamping strength, etc.

[0015] Furthermore, in the collision method using a pendulum as in Patent Document 1, it is difficult to hit the ball stably at the lowest point due to the characteristics of the club head shape (difference in FP (Face Progression) values, etc.), and the impact point position and collision angle may vary due to the deviation, and are difficult to adjust.

[0016] In addition, the above-mentioned Patent Document 2 can measure the rigidity characteristics of a golf club head simply and with a certain degree of accuracy, but there is a problem that the impact distance may vary at each measurement location due to the influence of the horizontal bulge surface (Bulge) and the vertical bulge surface (Roll) of the club face, and the measurement accuracy of the rigidity characteristics may be reduced.

[0017] The present invention has been made in view of the above circumstances, and an object of the present invention is to measure the rigidity characteristics of a collision target object simply and with high accuracy.

[0018] Technical means of solving problems

[0019] In order to achieve the above-mentioned purpose, one embodiment of the present invention is a rigidity characteristic measurement method, which holds a collision object in a manner that a measured surface is facing upward, causes the collision object to fall in a vertical direction toward the measured surface, and calculates the rigidity characteristics of the collision object based on the detection value of an acceleration sensor installed on the collision object. The rigidity characteristic measurement method is characterized in that it includes: a falling distance changing step, each time the measured position on the measured surface is changed, the falling distance of the collision body is adjusted in a manner that the collision speed of the collision body toward the measured position is set to be approximately constant.

[0020] In addition, one embodiment of the present invention is a rigidity characteristic measuring device for measuring the rigidity characteristics of a body to be collided, and the rigidity characteristic measuring device is characterized in that it comprises: a holding mechanism for holding the body to be collided in a manner such that the measured surface faces upward; a falling mechanism for causing the collision body to fall in a vertical direction toward the body to be collided; an acceleration sensor mounted on the collision body; a characteristic calculation unit for calculating the rigidity characteristics of the body to be collided based on the detection value of the acceleration sensor; and a falling distance changing unit for adjusting the falling distance of the collision body in a manner such that the collision speed of the collision body toward the measured portion is approximately constant each time the measured portion on the measured surface is changed.

[0021] Effects of the Invention

[0022] According to one embodiment of the present invention, each time the measured part on the measured surface is changed, the falling distance of the collision body is adjusted in such a way that the collision speed of the collision body toward the measured part is approximately constant, so that even when the measured surface has a curvature, the collision speed at each measured part can be approximately constant, which is beneficial for improving the measurement accuracy when the rigidity characteristic has speed dependence. In addition, according to the present invention, the collision body is made to fall toward the object to be collided in the vertical direction, so it is easy to keep the collision position and collision angle of the collision body constant, which is beneficial for improving the measurement accuracy of the rigidity characteristic. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an explanatory diagram showing the structure of the rigidity characteristic measuring device 10 according to the embodiment.

[0024] Figure 2 It is a diagram showing the structure of the golf club head 30.

[0025] Figure 3 This is a diagram showing a state where the golf club head 30 is attached to the head fixing jig 12 .

[0026] Figure 4 It is a figure which shows the structure of the collision lever 24.

[0027] Figure 5It is an explanatory diagram showing the operation of the collision lever 24 during collision.

[0028] Figure 6 It is a block diagram showing the configuration of the computer 50 .

[0029] Figure 7 1 is a flowchart showing a measurement procedure of the rigidity characteristic measuring device 10 .

[0030] Figure 8 : is a graph showing time series data of the velocity V of the collision rod 24 .

[0031] Fig. 9 This is a graph showing an example of CT values ​​measured a plurality of times while changing the collision speed.

[0032] Fig.10 Yes Fig. 9 The transformed curve graph.

[0033] Fig.11 It is an explanatory diagram showing the difference in CT value caused by the presence or absence of the falling distance changing step.

[0034] Fig.12 It is an explanatory diagram schematically showing a measurement location on the golf club head 30 .

[0035] Fig.13 It is an explanatory diagram schematically showing the operation of the cam 2702 and the operation lever 2410.

[0036] Fig.14 It is a block diagram showing the functional configuration of the computer 50 .

[0037] Fig.15 It is an explanatory diagram showing an example of the collision angle adjustment mechanism 80 . DETAILED DESCRIPTION

[0038] Hereinafter, preferred embodiments of the rigidity characteristic measuring device of the present invention will be described in detail with reference to the accompanying drawings.

[0039] The rigidity characteristic measuring device is a device for measuring the rigidity characteristic of the object to be collided. In this embodiment, the object to be collided is the golf club head 30, and the CT value of the golf club head 30 is measured as the rigidity characteristic.

[0040] First, the golf club head 30 which is the collision target will be described.

[0041] like Figure 2 As shown, the golf club head 30 includes a face 32 , a crown 33 , a sole 34 , and a side 35 , and has a hollow structure.

[0042] The face 32 forms a striking surface for striking a golf ball.

[0043] The crown 33 is connected to the face 32 .

[0044] The sole 34 is connected to the face 32 and the crown 33 .

[0045] The side portion 35 is connected to the crown 33 and the sole 34 , and faces the face 32 .

[0046] The golf club head 30 is made of, for example, metal, and preferably a high-strength, low-density metal such as a titanium alloy or an aluminum alloy is used.

[0047] Furthermore, in the crown 33 , a hosel 38 connected to a shaft 39 is provided at a position close to a heel 36 and on the face 32 side.

[0048] Furthermore, when the face 32 is viewed from the front, the side of the golf club head 30 opposite to the heel 36 is a toe 37 .

[0049] It should be noted that generally, the face 32 is not a flat surface but a curved surface (surface with curvature). More specifically, the curvature of the face 32 in the vertical direction (longitudinal direction, arrow R) is called a vertical curved surface, and the curvature in the horizontal direction (lateral direction, arrow B) is called a horizontal curved surface.

[0050] In addition, this embodiment uses Figure 2 The present invention is described with reference to a wood golf club head having a hollow structure, but is not limited thereto. For example, the present invention can also be applied to an iron golf club head having a hollow or solid structure or even a universal golf club head.

[0051] Figure 1 It is an explanatory diagram showing the structure of the rigidity characteristic measuring device 10 according to the embodiment.

[0052] The rigidity characteristic measuring device 10 holds the golf club head 30 (collision object) in a manner such that the club face 32 (measured surface) faces upward, and causes the collision rod 24 (collision object) to fall in a vertical direction toward the club face 32, and calculates the rigidity characteristic of the golf club head 30 based on the detection value of the acceleration sensor 26 mounted on the collision rod 24.

[0053] More specifically, the rigidity characteristic measuring device 10 includes a rod head fixing fixture 12, an XY table 14, a Z table 18, an arm 20, a linear bushing 22, a collision rod 24, an acceleration sensor 26, and a computer 50 (see Figure 6 ).

[0054] The club head fixing fixture 12 functions as a holding mechanism for holding the object to be collided in such a way that the measured surface faces the upper surface. In the present embodiment, the club head fixing fixture 12 is in the shape of a rectangular parallelepiped, and has: an upper surface 1202 facing the collision rod 24 arranged above, a lower surface (not shown) connected to the XY workbench 14, a side surface 1204 facing the left-right direction (X direction) of the paper, and a side surface 1206 facing the depth direction (Y direction) of the paper.

[0055] The upper surface 1202 is provided with a fitting hole 1208 for fitting the golf club head 30. The fitting hole 1208 is formed in the same shape as the side portion 35 of the golf club head 30. Figure 3 As shown, the golf club head 30 can be inserted in a manner that the club face 32 (measured surface) faces upward. The golf club head 30 inserted into the fitting hole 1208 is held by the club head fixing jig 12 in a manner that the club face 32 faces the upper surface. At this time, the shape of the fitting hole 1208 is formed in a manner that the club face 32 is approximately horizontal (in a manner that the normal line to the center of the surface is the vertical direction).

[0056] In addition, the side portion 35 of the golf club head 30 in the state of being fitted into the fitting hole 1208 is in contact with the club head fixing jig 12 (fitting hole 1208), but the crown 33 and the sole 34 are not in contact with the club head fixing jig 12. This is to prevent the club face 32 from being flexed by the crown 33 and the sole 34 directly in contact with the club face 32 being in contact with the club head fixing jig 12.

[0057] It should be noted that when measuring a golf club head 30 of a different model (shape), the head fixing jig 12 is replaced with one formed to match the shape of the golf club head 30 .

[0058] The head fixing jig 12 is formed of a vibration-damping material such as silicone, for example. This is to attenuate the vibration of the golf club head 30 generated when the collision rod 24 described later collides with the club face 32, thereby reducing the measurement noise of the acceleration sensor 26. That is, the head fixing jig 12 as a holding mechanism is formed to include a vibration-damping material that attenuates the vibration of the golf club head 30 as the collision object.

[0059] The XY stage 14 includes an X-axis direction stage 1402 , an X-axis direction stage 1404 , a Y-axis direction stage 1406 , and a Y-axis direction stage 1408 .

[0060] The head fixing jig 12 is placed on the Y-axis direction stage 1406. In addition, the Y-axis direction stage 1408 is placed on the X-axis direction stage 1402.

[0061] The X-axis worktable 1404 has a built-in moving mechanism such as a driver, which can move the X-axis stage 1402 on the X-axis worktable 1404 .

[0062] Similarly, the Y-axis workbench 1408 also has a built-in moving mechanism such as a driver, which can move the Y-axis stage 1406 on the Y-axis workbench 1404.

[0063] In this embodiment, the computer 50 (see Figure 6 ) is connected to the XY table 14, and the above-mentioned moving mechanism is automatically controlled to automatically move the club head fixing fixture 12 according to the specified timing.

[0064] It should be noted that the mechanism of the XY table 14 is not limited to the above-mentioned one, and various conventionally known mechanisms may be adopted.

[0065] In this embodiment, the head fixing fixture 12 (holding mechanism) is movable in the horizontal direction (XY direction) by the XY worktable 14, and the falling position of the collision rod 24 (collision body) on the club face 32 (measured surface) of the golf club head 30 (collision body) can be adjusted.

[0066] It should be noted that the linear bushing 22 (falling mechanism) to be described later may be movable in the horizontal direction (XY direction), thereby adjusting the falling position of the collision rod 24 (collision body) on the club face 32 (measured surface) of the golf club head 30 (collision body).

[0067] The pedestal 16 includes a bottom plate 1602 and a guide rail 1604 .

[0068] The bottom plate 1602 is disposed on a stable horizontal surface such as a workbench.

[0069] The guide rail 1604 is arranged along the Y-axis direction on the bottom plate 1602, and the X-axis direction table 1404 of the XY table 14 is arranged thereon. The X-axis direction table 1404 is movable on the guide rail 1604 in the paper depth direction (Y-axis direction).

[0070] A magnet (position fixing mechanism) not shown is mounted on the terminal portion of the paper back side (Z worktable 18 side) of the guide rail 1604. In the present embodiment, the X-axis direction worktable 1404 of the XY worktable 14 is formed of a metal such as stainless steel, and when the X-axis direction worktable 1404 moves to the terminal portion (measurement position) on the paper back side of the guide rail 1604, the position of the XY worktable 14 is fixed by the X-axis direction worktable 1404 being attracted by the magnet.

[0071] By adopting the pedestal 16 using such a guide rail 1604 , when the golf club head 30 is mounted on the head fixing jig 12 , the head fixing jig 12 can be moved to a position that does not interfere with a linear bushing 22 to be described later in the vertical direction.

[0072] It should be noted that, instead of using such a club head setting mechanism using the guide rail 1604, the stroke of the XY table 14 in the Y-axis direction (the stroke of the Y-axis direction table 1408) may be increased. In particular, in the case of an automatic control type XY table 14 as in this case, if the club head supply position when the golf club head 30 is set in the club head fixing fixture 12 and the subsequent measurement position are set in advance in the program, the respective positions can be easily and accurately reproduced instantly by operating the computer 50.

[0073] The Z stage 18 moves the arm 20 in the height direction (Z-axis direction), and includes a support column 1802 and a moving mechanism (not shown).

[0074] The support column 1802 is provided to stand upward from the end of the bottom plate portion 1602 in the vertical direction (Z-axis direction).

[0075] The moving mechanism includes an actuator and the like, and moves the arm 20 in the height direction along the groove 1804 provided in the support column 1802 .

[0076] In this embodiment, the computer 50 (see Figure 6 ) is connected to the Z workbench 18, and the arm 20 is automatically moved at a specified timing by automatically controlling the above-mentioned moving mechanism.

[0077] It should be noted that the mechanism of the Z stage 18 is not limited to the above-mentioned one, and various conventionally known mechanisms may be adopted.

[0078] The arm 20 extends from the support column 1802 in the horizontal direction (Y-axis direction) toward the front surface of the device (the side where the XY table 14 and the like are arranged).

[0079] The arm 20 is movable in the vertical direction through the Z table 18, so the linear bushing 22 connected to the arm 20 is also movable in the vertical direction, and the distance between the falling start position of the collision rod 24 (collision body) described later and the club face 32 (collision surface) of the golf club head 30 (collision body) in the vertical direction (vertical direction) can be adjusted. That is, the Z table 18 functions as a falling distance adjustment mechanism.

[0080] The reason why the distance between the falling start position of the collision rod 24 and the club face 32 in the vertical direction can be adjusted in this way is that the collision speed of the collision rod 24 to the club face 32 changes according to the distance. It is known that the CT value measured in this embodiment has speed dependence. Therefore, it is necessary to predetermine the collision speed of the collision rod 24 to the club face 32 and measure it at the collision speed. By providing a falling distance adjustment mechanism, the collision speed of the collision rod 24 to the club face 32 can be arbitrarily adjusted.

[0081] The linear bushing 22 is mounted on the tip of the arm 20 and functions as a drop mechanism for dropping a collision rod 24 (collision body) described later toward a golf club head 30 (collision target body) in a vertical direction (longitudinal direction of the columnar collision rod 24).

[0082] The linear bushing 22 includes a main body 2202 and an insertion hole 2204. The insertion hole 2204 penetrates from an upper surface 2206 of the main body 2202 to a lower surface 2208 (see Figure 5 A steel ball constituting a bearing mechanism is arranged on the inner peripheral surface of the insertion hole 2204 in the main body 2202 to guide the collision rod 24 inserted into the insertion hole 2204 downward in the vertical direction.

[0083] By restricting the falling direction of the collision rod 24 using the linear bushing 22 , the falling position relative to the golf club head 30 can be adjusted with high accuracy.

[0084] In addition, as the linear bushing 22, a type using a simple cylindrical sliding body may be used.

[0085] Also like Figure 4 As shown, the collision lever 24 (collision body) includes a lever body 2404 , an upper stopper 2406 , a lower stopper 2408 , and an operating lever 2410 .

[0086] The rod body 2404 is a cylindrical rod-shaped member formed of a metal such as stainless steel. It should be noted that the rod body 2404 may also be a columnar shape other than a cylinder (e.g., a prism shape). The bottom surface 2412 of one side of the rod body 2404 (the bottom surface on the side that collides with the golf club head 30 (collided body) in the use state) is formed in a spherical shape. The diameter of the rod body 2404 is formed according to the size that can be dropped from the insertion hole 2204 of the linear bushing 22.

[0087] The upper stopper 2406 is mounted on the upper end portion (the end portion on the side opposite to the bottom surface 2412) of the rod body 2404. The upper stopper 2406 has an outer diameter larger than the inner diameter of the insertion hole 2204 of the linear bushing 22, so the upper stopper 2406 cannot move into the insertion hole 2204 of the linear bushing 22. As a result, when the collision rod 24 falls, the collision rod 24 cannot move below the position where the upper stopper 2406 abuts against the upper surface 2206 of the linear bushing 22. That is, the upper stopper 2406 limits the lowest point position of the collision rod 24 located in the insertion hole 2204 of the linear bushing 22.

[0088] It should be noted that in actual use, Figure 1 and Figure 5 As shown, the spring 28 is sandwiched between the upper stopper 2406 and the upper surface 2206 of the linear bushing 22, so the upper stopper 2406 and the upper surface 2206 are not in direct contact. The spring 28 is, for example, a compression coil spring, and the rod body 2404 of the collision rod 24 is inserted into the inner diameter side thereof.

[0089] The details will be described later. The spring 28 functions as a re-collision prevention mechanism. After the collision rod 24 (collision body) collides with the club face 32 (measured surface), the collision rod 24 is held above the club face 32 to prevent the collision rod 24 from colliding with the club face 32 again.

[0090] The lower stopper 2408 is mounted near the bottom surface 2412 of the rod body 2404 .

[0091] The lower stopper 2408 is formed of a flexible member, such as rubber.

[0092] The lower stopper 2408 also has an outer diameter larger than the inner diameter of the insertion hole 2204 of the linear bushing 22, so the lower stopper 2408 cannot move into the insertion hole 2204 of the linear bushing 22. Therefore, when the collision rod 24 is moved upward, the collision rod 24 cannot move above the position where the lower stopper 2408 contacts the lower surface 2208 of the linear bushing 22. That is, the lower stopper 2408 limits the highest point position of the collision rod 24 in the insertion hole 2204.

[0093] It should be noted that, in this embodiment, the collision rod 24 is moved upward by the cam mechanism 27 which will be described later. Figure 5 As shown in (A), the movement amount at this time is set within a range where the lower stopper 2408 does not contact the lower surface 2208 of the linear bushing 22 (a range where the collision rod 24 does not reach the highest point position).

[0094] In addition, the lower stopper 2408 can be detached from the rod body 2404. When the collision rod 24 is removed from the linear bushing 22, the rod body 2404 is moved upward and pulled out from the insertion hole 2204 after the lower stopper 2408 is removed from the rod body 2404. Then, when the collision rod 24 is assembled to the linear bushing 22, the rod body 2404 with the lower stopper 2408 removed is inserted into the insertion hole 2204 and moved downward to a position restricted by the spring 28. Thereafter, the lower stopper 2408 is assembled to the rod body 2404.

[0095] That is, as described above, the linear bushing 22 (falling mechanism) keeps the collision rod 24 (collision body) movable in the vertical direction, and the upper stopper 2406 and the lower stopper 2408 function as a stopper mechanism for limiting the highest point position and the lowest point position of the collision rod 24 when it is inserted (held) in the linear bushing 22.

[0096] The operation lever 2410 is a rod-shaped member mounted on the upper stopper 2406 , and is used when the position of the collision lever 24 is moved upward by the cam mechanism 27 .

[0097] The cam mechanism 27 includes a cam 2702, a motor 2704, and a shaft 2706. A bracket 2708 extending in the horizontal direction (X-axis direction) is mounted on the side of the linear bushing 22 (the side where the operating rod 2410 extends), and the motor 2704 is mounted on the bracket 2708. The cam 2702 rotates in the YZ plane with the shaft 2706 as the center by the rotation of the drive shaft 2706 of the motor 2704. When the cam 2702 is located at the top due to the rotation of the shaft 2706, the operating rod 2410 is pushed up, and the collision rod 24 moves upward as a whole.

[0098] exist Fig.13 The operation of the cam 2702 and the operating lever 2410 is shown in more detail. Fig.13 In the figure, for the sake of visual confirmation, the structure other than the cam 2702 and the operating lever 2410 is omitted.

[0099] In this embodiment, the cam 2702 is substantially semicircular, and its side surface has an arc portion Ar and a straight portion St. The cam 2702 rotates counterclockwise around the shaft 2706 so that the arc portion Ar side contacts the operating rod 2410. The shaft 2706 is located directly below the operating rod 2410.

[0100] like Fig.13 As shown in (A), when the cam 2702 is separated from the operating rod 2410, the collision lever 24 is in the normal position (the upper stopper 2406 is located on the spring 28 contracted by the weight of the collision lever 24).

[0101] like Fig.13 As shown in (B), when the arc portion Ar of the cam 2702 contacts the operating rod 2410, the collision rod 24 moves from the normal position (at Fig.13 (B) is represented by a dotted line) and is pushed upward.

[0102] like Fig.13 As shown in (C), when the end ed of the arc portion Ar of the cam 2702 is separated from the operating rod 2410, the collision rod 24 is pushed up from the state (in Fig.13 (C) is represented by a dotted line) falls freely downward.

[0103] With such a mechanism, the up-and-down movement of the collision rod 24 can be automatically performed.

[0104] It should be noted that the mechanism for moving the collision rod 24 up and down is not limited to the cam mechanism described above, and various conventionally known mechanisms may be employed.

[0105] As the dimensions of the collision rod 24, for example, it is preferably set as follows: the diameter of the rod body 2404 is greater than 12 mm and less than 20 mm, the length (the length from the boundary between the upper stopper 2406 and the acceleration sensor 26 to the bottom surface 2412) is greater than 60 mm and less than 120 mm, the mass (including the rod body 2404, the upper stopper 2406, the lower stopper 2408, and the operating rod 2410) is greater than 100 g and less than 200 g, the radius of curvature of the bottom surface 2412 is less than 30 mm, and the radius of curvature of the bottom surface 2412 is more preferably greater than 20 mm and less than 30 mm.

[0106] This is because the size of the collision body specified in the procedure of the pendulum test (see Non-Patent Document 1) is included in the above range.

[0107] Back to Figure 1 As described above, the acceleration sensor 26 is mounted on the surface of the collision rod 24 (collision body) opposite to the bottom surface 2412, and measures the acceleration of the collision rod 24 generated when the collision rod 24 collides with the rod face 32 (collided body).

[0108] The acceleration sensor 26 is connected to the computer 50 via the digital oscilloscope through the wiring 2602, and its detection value is output to the computer 50. In the digital oscilloscope, the analog signal output from the acceleration sensor is converted into a numerical value. It should be noted that the acceleration sensor 26 and the computer 50 can also be connected by wireless communication.

[0109] Figure 6 It is a block diagram showing the configuration of the computer 50 .

[0110] The computer 50 includes a CPU 52 , a ROM 54 , a RAM 56 , a hard disk device 58 , a magnetic disk device 60 , a keyboard 62 , a mouse 64 , a display 66 , a printer 68 , an input / output interface 70 , etc. These components are connected via an interface circuit and a bus (not shown).

[0111] The ROM 54 stores control programs and the like, and the RAM 56 provides a work area.

[0112] The hard disk device 58 stores a rigidity characteristic calculation program for calculating the rigidity characteristic (the CT value in the present embodiment) of the golf club head 30 (the object to be collided) based on the detection value of the acceleration sensor 26 .

[0113] The magnetic disk device 60 records and / or reproduces data on a recording medium such as a CD (Compact Disc) or a DVD (Digital Video Disc).

[0114] The keyboard 62 and the mouse 64 receive operation inputs from the operator.

[0115] The display 66 displays the output data, and the printer 68 prints the output data. The data is output through the display 66 and the printer 68.

[0116] The input / output interface 70 transmits and receives data to and from external devices such as the acceleration sensor 26 .

[0117] Fig.14 It is a block diagram showing the functional configuration of the computer 50 .

[0118] The CPU 52 executes the control program to function as a measurement location adjustment unit 502 , a drop distance change unit 504 , a drop control unit 506 , a rigidity characteristic calculation unit 508 , a characteristic distribution creation unit 510 , and a feature point extraction unit 512 .

[0119] The measurement location adjustment unit 502 changes the relative position between the collision rod 24 (collision body) and the golf club head 30 (collision body), thereby changing the measurement location on the club face 32 (measurement surface).

[0120] In this embodiment, the measurement position adjustment unit 502 changes the position of the golf club head 30 relative to the collision rod 24 and thus changes the measurement position on the club face 32 by outputting a control signal to the XY worktable 14 to instruct the movement of the X-axis direction stage 1402 and the Y-axis direction stage 1406 .

[0121] Fig.12 It is an explanatory diagram schematically showing a measurement location on the golf club head 30 .

[0122] like Fig.12 As shown in (B), in this embodiment, a measurement range M of a predetermined width is set on the face 32 of the golf club head 30. Fig.12 As shown in (A), the measurement range M is divided into a plurality of micro-areas, and the center position of each micro-area is set as the measurement location. Fig.12 In the example of , the size of the micro area is set to 2.5 mm square, and there are 17×21=357 measurement locations.

[0123] The measurement range M is preferably set to be symmetrical in the vertical (crown-sole) direction and the horizontal (toe-heel) direction, for example, with the center of the club face 32 as a reference. Fig.12 In the example of FIG. 1 , the center of the measurement part “9K” is aligned with the center of the club face 32 to set the measurement range M and the measurement part.

[0124] Alternatively, a pattern of setting values ​​(size and position of a small area) of a number of measurement locations may be prepared in advance, saved as a file on the hard disk device 58 of the computer 50, and appropriate setting values ​​may be called to change the measurement range M and the measurement location according to the golf club to be measured (driver, fairway wood, etc.).

[0125] During measurement, the measurement part adjustment unit 502 first controls the position of the XY table 14 in such a manner that the measurement part 1A is located directly below the collision rod 24. When the measurement of the measurement part 1A is completed, the measurement part adjustment unit 502 performs the following control: the position of the X-axis direction stage 1402 is moved in such a manner that the measurement part 1B is located directly below the collision rod 24. Similarly, when all the measurement parts of the first row (up to 1U) are measured, the measurement part adjustment unit 502 performs the following control: the position of the Y-axis direction stage 1406 is moved in such a manner that the measurement part 2U is located directly below the collision rod 24. Similarly, by repeatedly moving in the X-axis direction and the Y-axis direction, measurement is performed at 357 measurement parts.

[0126] That is, in this embodiment, the measurement position adjustment unit 502 gradually changes the relative position of the collision rod 24 (collision body) and the golf club head 30 (collided body) by a predetermined distance along two orthogonal axes (X axis and Y axis) in the horizontal plane.

[0127] Back to Fig.14 As described above, the falling distance changing unit 504 adjusts the falling distance of the collision rod 24 (collision body) so that the collision speed of the collision rod (collision body) toward the measurement position is substantially constant each time the measurement position on the club face 32 (measured surface) is changed.

[0128] As described above, it is known that the CT value measured in the present embodiment has speed dependence. Therefore, it is ideal that the collision speed of the collision rod 24 is constant in all the measuring positions. On the other hand, in the case where the club face 32 of the golf club head 30 is not a flat surface, but the arm 20 is fixed relative to the position of the club head fixing fixture 12, for example, the collision speed is different between the measuring position located at the center of the club face 32 and the measuring position located at the end of the club face 32. Thus, the Z workbench 18 is controlled by the falling distance changing unit 504, and the position (height) of the arm 20 is changed according to each measuring position, thereby changing the falling starting height of the collision rod 24.

[0129] The determination of the falling distance by the falling distance changing unit 504 may use any of the following methods, for example.

[0130] <Method 1>

[0131] The collision rod 24 is actually caused to collide with the club face 32 at each measurement location, and the acceleration is measured. The collision velocity is calculated by integrating the acceleration, and the position of the arm 20 is changed.

[0132] For example, when the collision speed is faster than the predetermined measured collision speed (when you want to slow down the collision speed), the position of the arm 20 is raised to increase the falling distance. When it is slow (when you want to speed up the collision speed), the position of the arm 20 is lowered to shorten the falling distance.

[0133] It should be noted that it is considered that the collision speed of the collision rod 24 may be slightly different each time the measurement is performed even if the drop distance is the same due to various factors. Therefore, when the collision speed during actual measurement is within the range of, for example, ±0.05 m / s relative to the collision speed during measurement, it is realistic to set this error within the allowable range.

[0134] In addition, it can be considered that, generally speaking, if you want to slow down the collision speed, you lower the position of the arm 20 to shorten the falling distance, and if you want to speed up the collision speed, you raise the position of the arm 20 to increase the falling distance. Figure 5 ), in the rigidity characteristic measuring device 10 used in the present embodiment, the collision rod 24 collides with the rod face 32 while compressing the spring 28. When the position of the arm 20 is raised to increase the distance between the falling start point of the collision rod 24 and the rod face 32, the spring 28 is greatly compressed during the collision, and the collision speed of the collision rod 24 is slower than before the position of the arm 20 is changed. It should be noted that if the position of the arm 20 is raised excessively, the collision rod 24 will not contact the rod face 32.

[0135] In addition, when the position of the arm 20 is lowered to shorten the distance between the falling start point of the collision rod 24 and the rod surface 32, the collision rod 24 collides with the rod surface 32 when the compression amount of the spring 28 is small (before deceleration), and the collision speed of the collision rod 24 becomes faster than before the position of the arm 20 is changed. It should be noted that if the position of the arm 20 is excessively lowered, the collision rod 24 also contacts the rod surface 32 when there is no load.

[0136] Therefore, the drop distance changing unit 504 adjusts the position of the arm 20 within a range in which the collision rod 24 contacts the rod face 32 when a load is applied and the collision rod 24 does not contact the rod face 32 when no load is applied.

[0137] That is, method 1 is a method in which the falling distance changing unit 504 integrates the acceleration signal obtained by the acceleration sensor 26 to calculate the collision speed, and adjusts the falling distance of the collision rod 24 (collision body) so that the collision speed is within a predetermined range.

[0138] <Method 2>

[0139] The position of the arm 20 is changed by measuring the separation distance (falling distance) between the tip of the collision rod 24 and the measurement location using a distance sensor.

[0140] In this case, for example, at the top end of the collision rod 24 or the lower surface 2208 of the main body 2202 of the linear bushing 22 (see Figure 5 ) An optical equidistance sensor is provided. When the distance sensor is provided at the top end of the collision rod 24, the distance measured by the distance sensor when the collision rod 24 is in the normal position is directly used as the falling distance. In addition, when the distance sensor is provided on the lower surface 2208 of the linear bushing 22, the distance measured by the distance sensor minus the distance from the lower surface 2208 of the linear bushing 22 to the top end of the collision rod 24 in the normal position is set as the falling distance, but the distance from the lower surface 2208 of the linear bushing 22 to the top end of the collision rod 24 in the normal position is fixed, so the difference of the measured values ​​of the sensor is directly set as the difference of the falling distance.

[0141] The drop distance changing unit 504 controls the Z stage 18 so that the measurement value of the distance sensor becomes a predetermined separation distance.

[0142] That is, in method 2, the falling distance changing unit 504 measures the separation distance between the collision rod 24 (collision body) and the measurement location before falling, and adjusts the falling distance of the collision rod 24 (collision body) so that the separation distance becomes constant.

[0143] The drop control unit 506 controls the drop state of the collision rod 24 relative to the golf club head 30. More specifically, the drop control unit 506 controls the driving state (rotation speed, position of the cam 2702) of the motor 2704 of the cam mechanism 27, and causes the collision rod 24 to drop toward the golf club head 30 at a predetermined timing. The predetermined timing refers to, for example, the timing when the position adjustment of the XY table 14 by the measurement position adjustment unit 502 and the change of the drop distance by the drop distance change unit 504 (when the above-mentioned method 2 is adopted) are completed.

[0144] The rigidity characteristic calculation unit 508 makes the collision rod 24 (collision body) fall to the measurement position, and calculates the rigidity characteristic of each measurement position based on the detection value of the acceleration sensor 26 during the fall. In this embodiment, the rigidity characteristic refers to the CT value of the golf club head 30 (more specifically, at each measurement position of the club face 32).

[0145] The acceleration detected by the acceleration sensor 26 is time-series acceleration data detected at a predetermined sampling interval. The stiffness characteristic calculation unit 508 performs filtering on the acceleration data to remove noise, then integrates the data and converts the data into time-series data of the velocity V.

[0146] Figure 8 : is a graph showing time series data of the velocity V of the collision rod 24 .

[0147] The rigidity characteristic calculation unit 508 calculates the CT value indicating the rigidity characteristic of the golf club head 30 as follows.

[0148] The highest speed in the time series data of speed V is defined as Vmax.

[0149] The time when the speed V reaches V1 (V1=α% of Vmax) is defined as the start time ts.

[0150] The time when the speed V reaches V2 (V2=β% of Vmax) is defined as the end time te.

[0151] α is set to 0 to 99%, β is set to 1 to 100%, and α<β is set.

[0152] The CT value is calculated from te-ts.

[0153] In addition, generally, α%=5% and β%=95%.

[0154] Furthermore, as described above, the CT value has speed dependency, and therefore, the CT value may be measured at a plurality of collision speeds, and a representative CT value of the golf club head 30 may be calculated based on the relationship between the collision speed and the CT value.

[0155] Fig. 9 This is a graph showing an example of CT values ​​measured a plurality of times with respect to the same golf club head 30 while changing the collision velocity (changing the position of the arm 20 ).

[0156] exist Fig. 9 In the figure, the horizontal axis is the collision velocity [m / s], and the vertical axis is the CT value [μs].

[0157] like Fig. 9 As shown in the curve graph, the slower the collision speed, the larger the CT value, and the faster the collision speed, the smaller the CT value.

[0158] Fig.10 Yes Fig. 9 The horizontal axis is converted to a value of -0.329 (V -0.329 ) after the curve diagram.

[0159] When such conversion is performed, the CT values ​​are arranged on a straight line. The intersection point (y-intercept) of the straight line and the Y axis is set as the representative CT value of the golf club head 30. Fig.10 In the example, the CT values ​​at various collision speeds are arranged at T = 248.6 + 13.73V -0.329 The straight line represents the CT value of 248.6.

[0160] It should be noted that in Fig. 9 and Fig.10 The middle diagram shows the result of 10 measurements with varying collision speeds, but generally, the representative CT value of the golf club head 30 is calculated with approximately three measurements (three speed levels).

[0161] Back to Fig.14 As described above, the characteristic distribution creating unit 510 creates the distribution of the rigidity characteristics in the measurement range M set in the horizontal plane based on the rigidity characteristics calculated corresponding to each measurement location.

[0162] In this embodiment, for example Fig.12 As shown in (A) of FIG. 1 , the distribution of the rigidity characteristics is visualized by using a contour map in which the micro-regions corresponding to the respective measurement sites are color-coded according to the CT value in the respective measurement sites.

[0163] exist Fig.12 In (A), the CT value (the value after rounding off the first decimal place) is displayed in different colors according to the range of 0 to 240, the range of 241 to 252, the range of 253 to 264, and the range above 265. Fig.12 In the example of (A), it is known that the region with a CT value of 265 or more exists at one location each on the left and right of the measurement range M. Also, it is known that the CT value is not necessarily large in the center of the measurement range M, that is, the center of the face 32 .

[0164] According to the above, the distribution of the rigidity characteristics in the measurement range M can be easily grasped, and the performance evaluation of the golf club head 30 can be performed efficiently.

[0165] It should be noted that the form of the rigid distribution is not limited to the contour map, and various forms known in the art may be used.

[0166] The characteristic point extraction unit 512 extracts characteristic points of the rigidity characteristics based on the distribution of the rigidity characteristics in the measurement range M created by the characteristic distribution creation unit 510 .

[0167] The characteristic point of the rigidity characteristic refers to, for example, a point (measurement location) at which the rigidity characteristic value has a maximum value or a minimum value, or a point (measurement location) at which the rigidity characteristic value has a local maximum value or a local minimum value within the measurement range M. The local maximum value (or local minimum value) refers to a point corresponding to the maximum value (or minimum value) of each peak value when the rigidity characteristic value has a plurality of peak values.

[0168] Usually the maximum value of CT value becomes a problem, so when the maximum value or the maximum value is concerned, Fig.12 In the example of (A), the maximum CT value in the measurement range M is 275 (274.529) of 7A. In addition, among the local maximum values ​​of the left and right regions with CT values ​​of 265 or more, the local maximum value in the left region is 275 (274.529) of 7A, and the local maximum value in the right region is 270 (270.233) of 8O.

[0169] Next, refer to Figure 7 The measurement procedure of the rigidity characteristic measuring device 10 is described with reference to the flowchart of FIG.

[0170] exist Figure 7 In the flowchart of , a plurality of golf club heads 30 of the same model are prepared for mass production, and the rigidity characteristics (eg, CT value) of each golf club head 30 are measured. Figure 7 In the flowchart, the above-mentioned method 2 is used to determine the falling distance by the falling distance changing unit 504.

[0171] Prior to measurement, measurement parameters such as the measurement location of the rigidity characteristic (collision position of the collision bar 24 on the club face 32), the collision speed of the collision bar 24, and the separation distance between the collision bar 24 and the measurement location are determined in advance (step S70).

[0172] Next, the golf club head 30 is mounted on the head fixing jig 12 (step S72 ).

[0173] More specifically, first, the measurer moves the XY table 14 on the guide rail 1604 in the forward direction. This is to move the club head fixing jig 12 to a position where it does not interfere with the linear bushing 22 and the like when the golf club head 30 is set. Next, the club face 32 of the golf club head 30 is directed upward, and the side portion 35 is inserted into the fitting hole 1208. Then, the XY table 14 on the guide rail 1604 is moved inward (toward the Z table 18). When the XY table 14 moves to the end of the guide rail 1604, the position of the XY table 14 is fixed by a magnet.

[0174] Next, the measurement site adjustment unit 502 adjusts the initial measurement site (for example Fig.12 The control signal is output to the XY stage 14 so that the measuring part is located at the falling position of the collision bar 24. Thus, the XY stage 14 is operated and the measuring part is located at the falling position of the collision bar 24 (step S74, measuring part adjustment process).

[0175] Next, the falling distance changing unit 504 measures the separation distance (falling distance) between the top end of the collision rod 24 and the measurement position by a distance sensor (not shown), and changes the position of the arm 20 so as to achieve the separation distance set in step S70 (step S76, falling distance changing process).

[0176] The drop control unit 506 drives the motor 2704 of the cam mechanism 27 to drop the collision rod 24 toward the measurement site. In addition, a series of accelerations from the drop to the collision are measured by the acceleration sensor 26 (step S78).

[0177] Figure 5 It is a diagram schematically showing the operation of the collision lever 24 during measurement.

[0178] It should be noted that from the perspective of visual confirmation, Figure 5 (C) and Figure 5 In (D), the cam mechanism 27 is omitted.

[0179] like Figure 5 As shown in (A), during measurement, the operating rod 2410 of the collision rod 24 is lifted upward by the cam 2702. In this embodiment, even when the collision rod 24 is lifted by the cam 2702, the lower stopper 2408 is located below the lower surface 2208 of the linear bushing 22.

[0180] It should be noted that during measurement, a spring 28 is inserted through the rod body 2404 of the collision rod 24. The spring 28 is located on the upper surface 2206 of the linear bushing 22. Figure 5 In the state (A), no force is applied to the spring 28, so the length of the spring 28 is the natural length H0.

[0181] like Figure 5 As shown in (B), when the cam 2702 rotates and separates from the operating rod 2410, the collision rod 24 is allowed to fall freely in the vertical direction, and the falling speed is accelerated by the acceleration of gravity.

[0182] Thereafter, when the upper stopper 2406 drops to the upper end position of the spring 28, the load (mass x acceleration) of the collision rod 24 is applied to the spring 28. Due to this load, the spring 28 contracts and becomes a length H1 shorter than the natural length H0 (see Figure 5 (C) On the other hand, the reaction force from the spring 28 is applied to the collision rod 24, and the falling speed is decelerated. During this deceleration process, the collision rod 24 collides with the rod face 32 at a predetermined collision speed.

[0183] After colliding with the rod face 32, the collision rod 24 receives a reaction force and moves upward. When the collision rod 24 moves upward, the load applied to the spring 28 disappears, and the spring 28 returns to its natural length H0. After moving upward for a fixed distance, the collision rod 24 falls downward again (toward the rod face 32) due to gravity. However, compared with the initial fall, the falling start position is lower, so the load applied to the spring 28 becomes smaller, and the load does not reach the level of contraction of the spring 28 (or the contraction amount is less than the initial fall). Figure 5 (C) small).

[0184] Therefore, if Figure 5 As shown in (D), the bottom surface 2412 of the collision rod 24 is maintained above the club face 32. That is, the spring 28 functions as a re-collision prevention mechanism, which holds the collision rod 24 above the club face 32 after the collision of the collision rod 24 (collision body) and the club face 32 (measured surface), thereby preventing the collision rod 24 from colliding with the club face 32 again.

[0185] Such a re-collision prevention mechanism is provided in order to prevent the noise of the detection value of the acceleration sensor 26 from increasing due to the re-collision.

[0186] Back to Figure 7 As described above, the rigidity characteristic calculation unit 508 calculates the rigidity characteristic (CT value) of the golf club head 30 using the acceleration detected in step S78 (step S80).

[0187] When the measurement of all the measurement locations set in the golf club head 30 in this measurement is completed (step S82: No), the process returns to step S74, and the measurement locations are moved to continue the measurement and calculation of the rigidity characteristics.

[0188] When the measurement at all the measurement locations is completed (step S82: Yes), the characteristic distribution creating unit 510 plots the values ​​of the rigidity characteristics at each measurement location on a contour map to create a distribution of the rigidity characteristics in the measurement range M (step S84, characteristic distribution creating step).

[0189] Furthermore, the feature point extraction unit 512 determines the feature points of the rigidity characteristics (measurement locations that take maximum values ​​or local maximum values) based on the distribution of the rigidity characteristics (step S86 , feature point extraction step).

[0190] Until the measurement of the plurality of golf club heads 30 is completed (step S88: No), the golf club head 30 attached to the head fixing jig 12 is replaced (step S90), and the process returns to step S74 to repeat the subsequent processing.

[0191] Then, when the measurement of all the prepared plurality of golf club heads 30 is completed (step S88: Yes), the process of this flowchart is terminated.

[0192] Fig.11 It is an explanatory diagram showing the difference in CT value caused by the presence or absence of the falling distance changing step.

[0193] Fig.11 (A) shows the CT values ​​measured by setting points separated by a predetermined distance in the vertical direction as measurement locations (hitting locations) from the center position (measurement location 0) of the face 32 of the golf club head 30. Fig.11 (B) indicates Fig.11 The graph of the values ​​of (A) has the CT value on the vertical axis and the measurement site on the horizontal axis.

[0194] The center position of the club face 32 (measurement location 0), a point 10 mm and a point 20 mm upward from the measurement location 0, and a point 10 mm (-10 mm) and a point 20 mm (-20 mm) downward from the measurement location 0 are set as measurement locations.

[0195] When the falling distance changing process is not implemented and the falling starting height of the collision rod 24 is set constant based on the measuring position 0 (when all measuring positions are measured from the height at which the collision speed at the measuring position 0 is 0.40 m / s), the collision speed at other measuring positions is slower than 0.40 m / s, for example, the collision speed at the measuring position -20 mm is 0.33 m / s. In addition, the CT value is the largest at the measuring position 0, and the CT value is smaller at the measuring position with a larger distance from the measuring position 0.

[0196] On the other hand, when the falling distance changing process is implemented, the falling start height of the collision rod 24 is changed in a manner of setting the collision speed to 0.40m / s at all the measuring positions, compared with the case where the falling start height is constant, the CT value becomes smaller at all the measuring positions. As mentioned above, the CT value has speed dependency, so it can be considered that the method of measuring the CT value at a constant collision speed is more reliable. In particular, the larger the distance from the measuring position 0 is, the greater the error caused by the influence of the curvature of the club face 32, so it is effective to implement the falling distance changing process for measurement.

[0197] Furthermore, the curvature of the face 32 means that the normal direction of each point of the face 32 is also different. In order to more strictly measure the rigidity characteristics, it is ideal that the collision angle of the collision rod 24 is consistent (perpendicular) at each measurement location.

[0198] Therefore, in order to make the falling direction of the collision rod 24 (collision body) roughly consistent with the normal direction of the measurement part of the club face 32, a collision angle adjustment mechanism 80 for adjusting the holding angle of the golf club head 30 (collision body) can also be provided to perform the collision angle adjustment process.

[0199] Fig.15 It is an explanatory diagram showing an example of the collision angle adjustment mechanism 80 .

[0200] The collision angle adjustment mechanism 80 comprises: a gripping portion 82 for gripping the club head fixing fixture 12; a grounding portion 84 disposed on a plane (at Fig.15 In the example, it is the Y-axis direction stage 1406); and a rotating portion 86, which allows the holding portion 82 to rotate at an arbitrary angle.

[0201] The gripping portion 82 comprises: a base portion connected to the bottom surface of the cross-shaped club head fixing fixture 12; and a rising portion extending from the front end of the base portion to the upper side in the vertical direction and connected to the side surfaces 1204 and 1206 of the club head fixing fixture 12, thereby holding the club head fixing fixture 12.

[0202] exist Fig.15 In the state (A), the falling direction of the collision rod 24 is consistent with the normal direction (indicated by the arrow from the measurement part A) of the measurement part A located at the approximate center of the club face 32. On the other hand, the normal direction (indicated by the arrow from the measurement part B) of the measurement part B located at the end of the club face 32 is offset to the falling direction of the collision rod 24.

[0203] Therefore, when measuring at the measurement site B, Fig.15 As shown in (B), the gripping portion 82 is rotated by the rotating portion 86 so that the falling direction of the collision rod 24 coincides with the normal direction of the measurement site B.

[0204] It should be noted that the normal direction of each measurement location is calculated based on the design data of the golf club head 30 , for example.

[0205] Through the above, the rigidity characteristics of each measurement location on the curved surface can be measured with higher accuracy.

[0206] As described above, in the rigidity characteristic measuring device 10 of the embodiment, each time the measuring position on the club face 32 is changed, the falling distance of the collision body 24 is adjusted in such a manner that the collision speed of the collision body 24 toward the measuring position is substantially constant. Therefore, even when the club face 32 has a curvature, the collision speed at each measuring position can be set to be substantially constant, which is advantageous in improving the measurement accuracy when the rigidity characteristic has speed dependence.

[0207] In the rigidity characteristic measuring device 10, if the collision speed is calculated using the acceleration sensor 26 for measuring the rigidity characteristic and the falling distance is adjusted (the above-mentioned method 1), it is advantageous in reducing the cost of implementing the falling distance changing process.

[0208] Furthermore, in the rigidity characteristic measuring device 10, if the falling distance is adjusted so as to measure the separation distance between the collision rod 24 and the measuring portion (the above-mentioned method 2), it is advantageous in that the falling distance can be adjusted quickly and the measurement can be performed efficiently.

[0209] Furthermore, in the rigidity characteristic measuring device 10 , if the holding angle of the object to be collided is adjusted so that the falling direction of the collision rod 24 and the normal direction of the measurement portion are substantially consistent, it is advantageous in further improving the measurement accuracy of the rigidity characteristic.

[0210] Furthermore, the rigidity characteristic measuring device 10 measures the rigidity characteristic while changing the relative position of the collision rod and the golf club head 30 along two orthogonal axes in the horizontal plane. Therefore, it is advantageous in continuously measuring the rigidity characteristic of the golf club head 30 .

[0211] Furthermore, the rigidity characteristic measuring device 10 creates a distribution of rigidity characteristics in a measurement range set in a horizontal plane based on the rigidity characteristics calculated corresponding to a plurality of measurement locations, and is therefore advantageous in understanding the rigidity characteristics of the entire golf club head 30 .

[0212] Furthermore, the rigidity characteristic measuring device 10 extracts characteristic points of the rigidity characteristic based on the distribution of the rigidity characteristic, and therefore is advantageous in evaluating the rigidity characteristic of the golf club head 30 .

[0213] Furthermore, the rigidity characteristic measuring device 10 can easily and accurately measure the CT value, which is an important evaluation index of the golf club head 30 .

[0214] Furthermore, the rigidity characteristic measuring device 10 makes the collision rod 24 as the collision body fall vertically toward the golf club head 30 as the collision target body, so it is easy to keep the collision position and collision angle of the collision rod 24 constant, which is advantageous in improving the measurement accuracy of the rigidity characteristic.

[0215] Furthermore, since the collision rod 24 of the rigidity characteristic measuring device 10 is columnar, it is easy to restrict the movement path along the longitudinal direction, and it is easier to keep the collision position and collision angle of the collision rod 24 constant, which is advantageous in further improving the measurement accuracy of the rigidity characteristics.

[0216] Furthermore, since the bottom surface 2412 (collision surface) of the collision rod 24 is formed in a spherical shape, measurement based on a pendulum test can be performed.

[0217] In addition, the rigidity characteristic measuring device 10 is provided with an upper stopper 2406 and a lower stopper 2408 (stopper mechanism) for limiting the highest point position and the lowest point position of the collision rod 24, thereby being able to keep the falling distance of the collision rod 24 constant, which is advantageous in setting the collision speed toward the rod surface 32 constant.

[0218] In addition, the rigidity characteristic measuring device 10 is provided with a spring 28 (re-collision preventing mechanism) for preventing the collision rod 24 from colliding with the club face 32 again, which is advantageous in reducing the influence of repeated collisions in a short period of time on the measurement. In addition, the collision rod 24 is kept above the club face 32, so that the working efficiency when replacing the golf club head 30 as the measurement object can be improved, and scratches on the club face 32 can be prevented.

[0219] In addition, the rigidity characteristic measuring device 10 is provided with a falling distance adjustment mechanism (position fixing mechanism 2006 of the arm 20) for adjusting the distance between the falling starting position of the collision rod 24 and the rod surface 32 (the falling distance of the collision body), so that the collision speed of the collision rod 24 can be adjusted to an arbitrary speed, and in particular, the convenience of measuring rigidity characteristics with speed dependence can be improved.

[0220] Furthermore, the rigidity characteristic measuring device 10 can adjust the falling position of the collision rod 24 on the face 32 , and thus can measure the rigidity characteristic at any position on the face 32 .

[0221] Furthermore, since the head fixing jig 12 of the rigidity characteristic measuring device 10 is formed to include a vibration-damping material, it is advantageous in preventing excessive noise from being superimposed on the detection value of the acceleration sensor 26 and performing stable measurement.

[0222] Furthermore, in the rigidity characteristic measuring device 10 , only the golf club head 30 to which the shaft is not attached can be used as the collision target object, so that the CT value can be easily measured in the trial production process and the manufacturing process of the golf club head 30 .

[0223] It should be noted that in this embodiment, the CT value is calculated as the rigidity characteristic of the golf club head 30, but other rigidity characteristics that can be calculated using the detection value of the acceleration sensor 26, such as the rebound coefficient (ratio of relative speeds before and after collision), may also be calculated.

[0224] Explanation of symbols

[0225] 10 Rigidity characteristic measuring device

[0226] 12 Club head fixing clamp

[0227] 14 XY table

[0228] 16 pedestals

[0229] 1802 Pillar

[0230] 20 Arm

[0231] 22 Linear Bushing

[0232] 24 collision rod (collision body)

[0233] 2404 Rod body

[0234] 2406 Upper stop

[0235] 2408 Lower stop

[0236] 2410 Operating lever

[0237] 2412 Bottom

[0238] 26 Acceleration sensor

[0239] 27 Cam mechanism

[0240] 28 Spring (re-collision prevention mechanism)

[0241] 30 Golf club head (collision object)

[0242] 32 Club face (surface to be measured)

[0243] 50 Computer (characteristic calculation unit)

[0244] 502 Measurement part adjustment department

[0245] 504 Falling distance change unit

[0246] 506 Falling Control Unit

[0247] 508 Rigidity characteristic calculation unit

[0248] 510 Characteristic Distribution Production Department

[0249] 512 Feature point extraction unit

[0250] 80 Collision angle adjustment mechanism

Claims

1. A rigidity characteristic measuring method for measuring the rigidity characteristics of a plurality of micro areas within a set measurement range on a measurement surface of a collision object as a measurement object, wherein: holding the object to be collided with the surface to be measured facing upward, Based on an instruction from a computer in which the positions of the plurality of micro-areas are set in a program, a driver moves the object to be collided and the collision body, adjusts the horizontal position of the object to be collided so that the collision body is located directly above the micro-areas of the measured surface, and sets the collision body to a predetermined height so that a predetermined collision speed is achieved when colliding with the object to be collided. causing the collision body to fall in a vertical direction toward the micro area of ​​the measured surface, The rigidity characteristic of the object to be collided is calculated based on the detection value of the acceleration sensor mounted on the collision object. During the period of measuring the rigidity characteristics of the plurality of micro areas, the method includes: The step of adjusting the collision body to the predetermined height by the driver and changing the falling distance of the collision body so that the collision speed of the collision body toward the micro area to be measured is constant each time the micro area to be measured on the measured surface is changed.

2. The method for measuring rigidity characteristics according to claim 1, wherein: In the step of changing the falling distance, the acceleration signal obtained by the acceleration sensor is integrated to calculate the collision velocity, and the falling distance of the collision body is determined so that the collision velocity is within a predetermined range.

3. The method for measuring rigidity characteristics according to claim 1, wherein: In the step of changing the falling distance, a separation distance between the collision body and the micro area to be measured before falling is measured, and the falling distance of the collision body is adjusted so that the separation distance becomes constant.

4. The method for measuring rigidity characteristics according to claim 1, wherein: Also includes: The collision angle adjustment step adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

5. The method for measuring rigidity characteristics according to claim 2, wherein: Also includes: The collision angle adjustment step adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

6. The method for measuring rigidity characteristics according to claim 3, wherein: Also includes: The collision angle adjustment step adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

7. The rigidity characteristic measuring method according to any one of claims 1 to 6, characterized in that: Also includes: a measurement position adjustment step of changing the micro area to be measured on the measured surface by changing the relative position of the collision body and the collision body; as well as a rigidity characteristic calculation step of causing the collision body to fall to the micro-area to be measured, and calculating the rigidity characteristic at each micro-area to be measured based on the detection value of the acceleration sensor during the fall, In the measurement portion adjustment step, the relative positions of the collision body and the collision target body are sequentially changed at predetermined distances along two orthogonal axes in a horizontal plane.

8. The method for measuring rigidity characteristics according to claim 7, wherein: Also includes: The characteristic distribution creating step creates a distribution of the rigidity characteristic in a measurement range set in the horizontal plane based on the rigidity characteristic calculated corresponding to each micro area to be measured.

9. The method for measuring rigidity characteristics according to claim 8, wherein: Also includes: The feature point extraction step extracts feature points of the rigidity characteristics based on the distribution of the rigidity characteristics in the measurement range created in the feature distribution creation step.

10. The rigidity characteristic measuring method according to any one of claims 1 to 6 and 8 to 9, characterized in that: The object to be collided is a golf club head, The rigidity characteristic is a CT value of the golf club head.

11. The method for measuring rigidity characteristics according to claim 7, wherein: The object to be collided is a golf club head, The rigidity characteristic is a CT value of the golf club head.

12. A rigidity characteristic measuring device for measuring rigidity characteristics of a plurality of micro areas within a set measurement range on a measurement surface of a collision object as a measurement object, the rigidity characteristic measuring device comprising: A holding mechanism for holding the object to be collided in such a manner that the measured surface faces upward; The falling mechanism comprises a collision body, which makes the collision body fall toward the collision object in a vertical direction; A computer having a control program for the rigidity characteristic measuring device, wherein the positions of the plurality of micro areas are set in the program; a driver that operates based on instructions from the computer; and An acceleration sensor, mounted on the collision body; The computer has: a measurement position adjusting unit that operates the actuator and moves the collision target and the collision target together with the holding mechanism, so as to adjust the horizontal position of the collision target in such a manner that the collision target is located directly above the micro area of ​​the measurement surface; a rigidity characteristic calculation unit, which calculates the rigidity characteristic of the object to be collided based on the detection value of the acceleration sensor; and a falling distance changing unit, which operates the driver, wherein the collision body is set to a predetermined height in such a manner that the collision speed becomes a predetermined collision speed when colliding with the collision object, and each time the micro area to be measured on the measured surface is changed, the falling distance of the collision body is adjusted in such a manner that the collision speed of the collision body toward the micro area to be measured is constant.

13. The rigidity characteristic measuring device according to claim 12, characterized in that: The falling distance changing unit integrates the acceleration signal obtained by the acceleration sensor to calculate the collision speed, and determines the falling distance of the collision body so that the collision speed falls within a predetermined range.

14. The rigidity characteristic measuring device according to claim 13, characterized in that: A distance sensor is further provided for measuring a separation distance between the collision body and the micro area to be measured before falling, and the falling distance changing unit adjusts the falling distance of the collision body based on the separation distance measured by the distance sensor so that the separation distance is fixed.

15. The rigidity characteristic measuring device according to claim 12, characterized in that: Also includes: The collision angle adjustment unit adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

16. The rigidity characteristic measuring device according to claim 13, characterized in that: Also includes: The collision angle adjustment unit adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

17. The rigidity characteristic measuring device according to claim 14, characterized in that: Also includes: The collision angle adjustment unit adjusts the holding angle of the collision target object so that the falling direction of the collision target object coincides with the normal direction of the micro area to be measured.

18. The rigidity characteristic measuring device according to any one of claims 12 to 17, characterized in that: The measurement site adjustment unit changes the micro area to be measured on the measured surface by changing the relative positions of the collision body and the collision body. The rigidity characteristic calculation unit causes the collision body to fall to the micro area to be measured, and calculates the rigidity characteristic at each micro area to be measured based on the detection value of the acceleration sensor during the fall. The measurement site adjustment unit sequentially changes the relative positions of the collision body and the collision target body by a predetermined distance along two orthogonal axes in a horizontal plane.

19. The rigidity characteristic measuring device according to claim 18, characterized in that: The computer also has: The characteristic distribution creating unit creates a distribution of the rigidity characteristic in a measurement range set in the horizontal plane based on the rigidity characteristic calculated corresponding to each micro area to be measured.

20. The rigidity characteristic measuring device according to claim 19, characterized in that: The computer also has: The feature point extraction unit extracts feature points of the rigidity characteristics based on the distribution of the rigidity characteristics in the measurement range created by the characteristic distribution creation unit.

21. The rigidity characteristic measuring device according to any one of claims 12 to 17 and 19 to 20, characterized in that: The object to be collided is a golf club head, The rigidity characteristic is a CT value of the golf club head.

22. The rigidity characteristic measuring device according to claim 18, characterized in that: The object to be collided is a golf club head, The rigidity characteristic is a CT value of the golf club head.

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