JP5447179B2 - Calculation method of maximum deflection point and maximum deflection in golf club head - Google Patents

Description

  The present invention relates to a method for calculating a maximum deflection point and a maximum deflection amount in a golf club head.

In designing a golf club, it is important to improve the flight distance of the hit ball. For this reason, it is required to make the initial velocity when the golf ball is hit with the golf club head as large as possible.
Factors that greatly affect the initial speed include the position of the maximum deflection point on the face surface of the golf club head and the maximum deflection amount.
Therefore, in designing a golf club, it is required to accurately obtain the position of the maximum deflection point and the maximum deflection amount when the golf ball is hit on the face surface.
On the other hand, a technique for measuring the amount of deflection of the face surface of a golf club head has been proposed (see Patent Document 1).
That is, in this method, the face surface (striking surface) of the golf club head is vibrated in the vertical direction to vibrate the striking surface, and the vibration distribution on the face surface (by a laser vibrometer disposed at a position facing the face surface ( Measure the amplitude distribution).
Therefore, when this method is used, the position of the maximum deflection point and the maximum deflection amount can be measured by actually manufacturing the golf club head and measuring the deflection amount of the manufactured golf club head.

JP 2004-138484 A

However, in the above prior art, since it is necessary to actually manufacture a golf club head, there is a disadvantage that it takes time and cost to manufacture the golf club head.
The present invention has been made in view of such circumstances, and the purpose thereof is to accurately obtain the position of the maximum deflection point and the maximum deflection amount in a short time and at low cost, thereby improving design efficiency. It is an object of the present invention to provide a method for calculating the maximum deflection point and the maximum deflection amount in a golf club head that is advantageous for the purpose.

In order to achieve the above object, the present invention provides a calculation method for obtaining the position of the maximum deflection point and the maximum deflection amount on the face surface of a golf club head, the face surface of the golf club head model comprising a finite element model. Is divided into a plurality of rectangular initial regions of the same shape and the same size, and an initial region hit point setting step for setting on the face surface with a vertex of each initial region as a hit point, and a golf ball constituted by a finite element model When the model is hit with one of the plurality of hit points, time series data of the amount of deflection generated at each of the plurality of hit points is obtained by a simulation of collision analysis by a finite element method, The plurality of processes for calculating an average value of peak values as an initial average maximum deflection amount corresponding to the one hit point. An initial average maximum deflection amount calculation step executed for all hit points, a specific region determination step for determining a specific region including the maximum deflection point based on the initial average maximum deflection amount, and the specific region having the same shape and size A small area hitting point setting step for setting on the face surface with the vertex of each small area as a hitting point, and a plurality of hitting points set in the small area hitting point setting step By performing the same process as the initial average maximum deflection amount calculating step, a narrowed average maximum deflection amount calculating step for calculating a narrowed average maximum deflection amount for each of a plurality of hit points, a position of the plurality of hit points and the narrowed average maximum deflection The maximum deflection point and the maximum deflection point are calculated by calculating the position of the maximum deflection point and the maximum deflection amount. Characterized in that it comprises a viewing amount calculation step.
The present invention also provides a calculation method for obtaining the position of the maximum deflection point and the maximum deflection amount on the face surface of the golf club head, wherein the face surface of the golf club head model configured by a finite element model is rectangular with the same shape and size. An initial region hit point setting step for dividing the shape into a plurality of initial regions and setting the vertex of each initial region on the face surface as a hit point, and a golf ball model composed of a finite element model of the plurality of hit points The time series data of the amount of deflection generated at each of the plurality of hit points when hitting at one of the hit points is obtained by a simulation of collision analysis by a finite element method, and the average value of the peak values of the respective time series data is calculated as described above. The process of calculating the initial average maximum deflection amount corresponding to one hit point is executed for all of the plurality of hit points. An initial average maximum deflection amount calculating step, a first specific region determining step for determining a specific region including a maximum deflection point based on the initial average maximum deflection amount, and the specific region having a rectangular shape of the same shape and size. A plurality of small areas are divided by a first small area hitting point setting step which is set on the face surface with the vertex of each small area as a hitting point, and a plurality of small area hitting points set in the first small area hitting point setting step. By performing the same processing as the initial average maximum deflection amount calculation step for the hit points, a first narrowed average maximum deflection amount calculation step for calculating a narrowed average maximum deflection amount for each of a plurality of hit points, and the narrowed average maximum deflection amount A second specific area determining step for determining a new specific area including the maximum deflection point based on the rectangle; And a second small area hitting point setting step for setting the vertex of each small area on the face surface as a new hitting point, and a second small area hitting point setting step. The second narrowed average maximum deflection amount for calculating a new narrowed average maximum deflection amount for each of a plurality of new hit points by performing the same processing as the initial average maximum deflection amount calculating step for a plurality of set new hit points. A calculation step, and a maximum deflection point and a maximum deflection amount calculating step for calculating a position of the maximum deflection point and a maximum deflection amount by interpolation using the positions of the plurality of hit points and the narrowed average maximum deflection amount. The second specific area determining step, the second small area hitting point setting step, and the second narrowed average maximum deflection amount calculating step. The step of calculating the maximum deflection point and the maximum deflection amount is executed after the step is repeatedly executed once or twice or more.

According to the present invention, when the golf ball model is hit with a plurality of hit points set on the face surface of the golf club head model, the time series data of the deflection amount generated at each of the plurality of hit points is used for the simulation of the collision analysis by the finite element method. The maximum deflection point and the maximum deflection amount are obtained based on these time series data.
Therefore, the position of the maximum deflection point and the maximum deflection amount can be accurately obtained in a short time and at a low cost without actually manufacturing a golf club head.

1 is a front view showing a golf club head 10 as an object of a method of the present invention. It is a block diagram which shows the structure of the computer 30 used in order to perform the method of this invention. It is a flowchart which shows the calculation method in 1st Embodiment. FIG. 3 is a functional block diagram showing a configuration of a computing device constituted by a computer 30. It is explanatory drawing of the golf club head model 10A and the golf ball model 2A. It is a figure explaining the division | segmentation of an initial region, and the setting of a hit point. 6 is a diagram showing a distribution of deflection amount on a face surface 12. FIG. 4 is a diagram showing time-series data of a deflection amount on a face surface 12 when a golf ball model 2A is hit at one hit point D. FIG. 6 is a schematic diagram of the face surface 12 displayed as an index with the initial average maximum deflection amount of the center point C of the face surface 12 being 100. FIG. It is a figure explaining the division | segmentation of a specific area | region, and the setting of a hit point. 5 is a schematic diagram showing a positional relationship between a maximum deflection point F and nine hit points D. FIG. It is a comparison figure of the calculated value of the position of the maximum deflection point, and an actual measurement value. It is a flowchart which shows the calculation method in 2nd Embodiment. FIG. 3 is a functional block diagram showing a configuration of a computing device constituted by a computer 30. 4 is a flowchart showing an analysis procedure of the golf club head 10. 4 is an explanatory diagram of rolling of the golf club head 10. FIG. 4 is an explanatory diagram showing a speed distribution set on the face surface 12 of the golf club head 10. FIG. 6 is an explanatory diagram of a face deflection distribution R set on the face surface 12. FIG. FIG. 6 is an explanatory diagram showing a contour line v of a speed distribution set on the face surface 12, a center of gravity point P, and a face maximum deflection point Q. It is explanatory drawing which shows the analysis result at the time of setting the threshold value c to the 1st threshold value c1. FIG. 6 is a schematic diagram showing the relationship among a center of gravity point P, a face maximum deflection point Q, a face speed Vf, and a ball initial speed. FIG. 6 is a schematic diagram showing the relationship among a center of gravity point P, a face maximum deflection point Q, a face speed Vf, and a ball initial speed. FIG. 6 is an explanatory diagram showing a state where a maximum face speed point Vfmax and a face maximum deflection point Q coincide with each other. It is explanatory drawing which shows the analysis result at the time of setting the threshold value c to the 2nd threshold value c2. FIG. 6 is a schematic diagram showing the relationship among a center of gravity point P, a face maximum deflection point Q, a face speed Vf, and a ball initial speed. FIG. 6 is a schematic diagram showing the relationship among a center of gravity point P, a face maximum deflection point Q, a face speed Vf, and a ball initial speed. FIG. 5 is an explanatory diagram showing a state where a minimum face speed point Vfmin and a face maximum deflection point Q coincide with each other. It is a flowchart which shows the calculation method in 3rd Embodiment. FIG. 3 is a functional block diagram showing a configuration of a computing device constituted by a computer 30. 6 is a schematic diagram showing a positional relationship among a gravity center point P, a maximum deflection point Q, and a maximum initial speed point R when the velocity distribution of the face surface 12 is not considered. FIG. (A), (B), and (C) are schematic diagrams for explaining the deviation of the maximum initial speed point R due to the influence of the velocity distribution of the face surface 12.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a golf club head that is an object of the calculation method of the present invention will be described.
As shown in FIG. 1, the golf club head 10 includes a face portion 14, a crown portion 16, a sole portion 18, and a side portion 20 and has a hollow structure.
The face portion 14 forms a face surface 12 for hitting a golf ball.
The crown portion 16 is connected to the face portion 14.
The sole portion 18 is connected to the face portion 14 and the crown portion 16.
The side portion 20 is connected to the crown portion 16 and the sole portion 18 and faces the face portion 14.
The golf club head 10 is made of metal, and the metal material of the golf club head 10 is preferably a high strength low specific gravity metal such as a titanium alloy or an aluminum alloy.
Further, the crown portion 16 is provided with a hosel 26 connected to the shaft 28 at a position near the heel 22 on the face surface 12 side.
Further, the toe 24 is located on the opposite side of the golf club head 10 from the heel 22 when the face surface 12 is viewed from the front.

FIG. 2 is a block diagram showing a configuration of a computer 30 for performing calculation for obtaining the position of the maximum deflection point and the maximum deflection amount of the golf club head 10.
In this specification, the maximum deflection point refers to the maximum deflection point in the primary vibration of the face surface 12, and the maximum deflection amount refers to the deflection amount at the maximum deflection point.
The computer 30 includes a CPU 32, a ROM 34, a RAM 36, a hard disk device 38, a disk device 40, a keyboard 42, a mouse 44, a display 46, a printer 48, an input / output interface 50, etc. connected via an interface circuit (not shown) and a bus line. have.
The ROM 34 stores a control program and the like, and the RAM 36 provides a working area.

  The hard disk device 38 includes a finite element analysis program for performing a finite element analysis of the golf club head 10 and a calculation program for calculating the position of the maximum deflection point and the maximum deflection amount using a simulation result obtained by the finite element analysis program. Storing.

As the finite element analysis program, various conventionally known commercially available finite element analysis software that performs finite element analysis, for example, ABAQUS (registered trademark of SIMULIA Americas) can be used.
The finite element analysis program includes the following programs.
1) A program for creating a finite element model:
In the present embodiment, the program is for creating a finite element model of the golf club head 10 and the golf ball.
2) A program for performing simulation (analysis) by the finite element method using a finite element model:
The present embodiment is a program for performing collision analysis using a finite element model of a golf club head and a finite element model of a golf ball.
3) Program for outputting simulation results:
It is a program for visualizing and outputting simulation results as figures and numerical tables in various forms including contour diagrams.

The disk device 40 records and / or reproduces data on a recording medium such as a CD or a DVD.
The keyboard 42 and the mouse 44 receive an operation input by the operator.
The display 46 displays and outputs data, and the printer 48 prints and outputs data. The display 46 and the printer 48 output data.
The input / output interface 50 exchanges data with an external device.

The computer 30 constitutes a calculation device for calculating the maximum deflection point and the maximum deflection amount in the golf club head.
As shown in FIG. 4, this calculation apparatus includes a model creation means 30A, an initial area hitting point setting means 30B, an initial average maximum deflection amount calculating means 30C, a specific area determining means 30D, and a small area hitting point setting means 30E. The narrowed average maximum deflection amount calculation means 30F, the maximum deflection point and maximum deflection amount calculation means 30G, and the output means 30H are included.
These means 30A to 30H are realized by the computer 30 executing the finite element analysis program and the calculation program.
Each means 30A thru | or 30H is demonstrated with the calculation method of this Embodiment.

Next, the calculation method of the present embodiment will be described with reference to the flowchart of FIG.
The following processes are performed by the computer 30 executing the finite element analysis program and the calculation program.
First, a golf club head model and a golf ball model, which are finite element models of the golf club head 10 and the golf ball, are created (step S10: model creation step).
The finite element model is created based on a conventionally known finite element method.
Step S10 is performed by the computer 30 executing a finite element analysis program.
This step S10 corresponds to the model creating means 30A in FIG.
Specifically, three-dimensional shape data of the golf club head 10 and the golf ball created using a three-dimensional CAD program, that is, design data (CAD data) is input to the computer 30.
In addition, various data including constraint conditions and material constants necessary for creating the finite element model of the golf club head 10 and the golf ball are input to the computer 30.
When the computer 30 executes the finite element analysis program, the three-dimensional shape data of the golf club head 10 and the golf ball are each divided into meshes.
As a result, as shown in FIG. 5, a golf club head model 10A is created as a finite element model of the golf club head 10, and a golf ball model 2A is created as a finite element model of the golf ball. In FIG. 5, the lines indicating the state in which the golf club head model 10A and the golf ball model 2A are divided into a large number of finite elements are omitted.

In the present embodiment, the golf club head model 10A is configured only by the finite element model of the face portion 14 shown in FIG. This is because the influence of the crown portion 16, the sole portion 18, and the side portion 20 on the behavior (deflection) of the face surface 12 can be ignored in simulation of collision analysis described later.
If the golf club head model 10A is configured with only the finite element model of the face portion 14 as in the present embodiment, the amount of calculation required for simulation of collision analysis described later can be reduced, and the position of the maximum deflection point and the maximum deflection amount. This is advantageous in shortening the time required to calculate.
Of course, the golf club head model 10 </ b> A may be configured by a finite element model of the golf club head 10 including all of the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20. Further, in the simulation of the collision analysis, the ball may collide with the head.

Next, the face surface 12 in the golf club head model 10A is divided into a plurality of rectangular initial regions having the same shape and the same size, and the vertex of each initial region is set on the face surface 12 as a hit point (step S12: initial). Area dot setting step).
Specifically, as shown in FIG. 6, the horizontal direction from the toe 24 side to the heel 22 side of the face surface 12 of the golf club head model 10A is set in the X direction with the golf club head model 10A set according to the lie angle. And the vertically upward direction is the Y direction.
In this case, a plurality of horizontal lines Lx extending in parallel with the X direction at equal intervals in the Y direction and a plurality of vertical lines Ly extending in parallel with the Y direction at equal intervals in the X direction. The face surface 12 is divided into a plurality of initial regions A having the same shape and size.
Then, an intersection point (vertex of the initial region) between the horizontal line Lx and the vertical line Ly is set on the face surface 12 as a hit point D.
In the present embodiment, the horizontal line Lx is three lines Lx1, Lx2, and Lx3, and the vertical line Ly is three lines Ly1, Ly2, and Ly3.
The interval between the horizontal lines Lx is 6 mm, and the interval between the vertical lines Ly is 7 mm.
Further, the initial area A is four of A1 to A4.
The hit points D are nine points D1 to D9, and the hit point D5 coincides with the center point C of the face surface 12.
Note that the number of horizontal lines Lx and vertical lines Ly may not be the same.
Step S12 is performed by the computer 30 executing the calculation program.
This step S12 corresponds to the initial area hit point setting means 30B in FIG.

Next, an initial average maximum deflection amount is obtained for all the hit points D (step S14: initial average maximum deflection amount calculation step).
Specifically, when the golf ball model 2A is hit at one of the plurality of hit points D, time series data indicating the amount of deflection generated at each of the plurality of hit points D is used for simulation of collision analysis by the finite element method. (Step S14A).
Then, the average value of the peak values of each time series data is calculated as the initial average maximum deflection amount corresponding to one hit point D (step S14B).
These steps S14A and S14B are executed for all of the plurality of hit points.

FIG. 7 is a diagram showing the distribution of the deflection amount on the face surface 12. In this example, contour lines k connecting the points with the same deflection amount are displayed.
In step S14A, as shown in FIG. 7, the amount of deflection on the face surface 12 when the golf ball model 2A is hit at one hitting point D is obtained.
FIG. 8 is a diagram showing time-series data of the deflection amount on the face surface 12 when the golf ball model 2A is hit at one hitting point D, with the elapsed time (sec) on the horizontal axis and the deflection amount (mm) on the vertical axis. Have taken.
In FIG. 8, all the time series data gy of the deflection amount of nine hit points D are described.
In step S14B, as shown in FIG. 8, the peak of the time series data indicating the amount of deflection generated at each of the hit points D1 to D9 is obtained, and the average value of the peaks of these nine hit points D1 to D9 is set as one hit point D. Calculated as the corresponding initial average maximum deflection.
FIG. 9 is a schematic diagram of the face surface 12 indicated by an index with the initial average maximum deflection amount of the hit point D5 among the hit points D1 to D9, that is, the center point C of the face surface 12 being 100. The maximum value of the initial average maximum deflection amounts of the hit points D1 to D9 may be an index with an index 100, and is arbitrary.
By step S14, the initial average maximum deflection amount of the hit points D1 to D9 is obtained as shown in FIG.
In the present embodiment, step S14A is performed when the computer 30 executes the finite element analysis program, and step S14B is performed when the computer 30 executes the dedicated program.
In other words, step S14 is performed by the computer 30 executing a finite element analysis program and a calculation program.
This step S14 corresponds to the initial average maximum deflection amount calculation means 30C in FIG.

Next, a specific area including the maximum deflection point is determined based on the initial average maximum deflection amount of each hit point D (step S16: specific area determination step).
The specific area is determined as follows, for example.
That is, based on the magnitude relationship between the initial average maximum deflection amounts of the hit points D shown in FIG. 9, it is determined in which of the initial regions A1 to A4 the maximum deflection point is located.
For example, the sum of the initial average maximum deflection amounts of the four hit points D located at the four vertices of each initial region is obtained, and the initial region A1 having the largest sum is determined as the specific region including the maximum deflection point. To do.
Step S16 is performed by the computer 30 executing the calculation program.
This step S16 corresponds to the specific area determining means 30D in FIG.

In the present embodiment, the specific area is determined as follows.
In the same manner as described above, the initial region A1 in which the sum of the initial average maximum deflection amounts has the largest value is selected.
Then, from the selected initial region A1, a region having an area smaller than that of the initial region A1 is determined as the specific region A10 as shown by hatching in FIG.
That is, as shown in FIGS. 9 and 10, a rectangular area in which the dimensions in the X direction and the Y direction are 1 mm × 1 mm, respectively, including the hit point D5 in which the initial average maximum deflection amount takes the maximum value in the initial area A1. Is determined as the specific area A10.
The specific area A10 is determined based on the initial average maximum deflection amount at the hit points D1, D2, D4, and D5 corresponding to the four vertices of the selected initial area A1.
For example, the initial average maximum deflection amount obtained by interpolation using a quadratic function based on the positions of four hit points D1, D2, D4, D5 and the size of the initial average maximum deflection amount of these four hit points. The specific area A10 may be determined based on the distribution.
In the present embodiment, step S16 is performed by the computer 30 executing the dedicated program.

Next, the specific area A10 is divided into a plurality of rectangular small areas having the same shape and the same size, and the apex of each small area is set on the face surface 12 as a hitting point (step S18: small area hitting point setting step).
Specifically, as shown in FIG. 10, the specific area A10 is divided into a plurality of small areas A101, A102, A103, and A104 having the same shape and size by a horizontal line Lx ′ and a vertical line Ly ′.
Then, an intersection point (vertex of each small area) between the horizontal line Lx ′ and the vertical line Ly ′ is set on the face surface 12 as a hit point D ′.
In this case, the plurality of horizontal lines Lx ′ extend in parallel with the X direction at equal intervals in the Y direction, and the plurality of vertical lines Ly ′ extend in parallel with the Y direction at equal intervals in the X direction. To do.
Step S18 is performed by the computer 30 executing the calculation program.
This step S18 corresponds to the small area dot setting means 30E in FIG.

Next, the same processing as in step S14 (initial average maximum deflection amount calculation step) is performed for the plurality of hit points D ′ set in step S18, thereby calculating the narrowed average maximum deflection amount for each of the plurality of hit points D ′ ( Step S20: Refined average maximum deflection amount calculation step).
FIG. 10 shows the striking point D ′ 9 out of the striking points D ′ 1 to D ′ 9, that is, an index with the narrowed average maximum deflection amount of the center point C of the face surface 12 as 100. An index with the maximum value being 100 may be used and is arbitrary.
Step S20 is performed by the computer 30 executing a finite element analysis program and a calculation program.
This step S20 corresponds to the narrowed average maximum deflection amount calculation means 30F in FIG.

Next, the position of the maximum deflection point and the maximum deflection amount are calculated by interpolation using a quadratic function using the positions of the plurality of hit points D′ 1 to D′ 9 and the narrowed average maximum deflection amount ( Step S22: Maximum deflection point and maximum deflection amount calculation step).
In the present embodiment, interpolation is performed using a quadratic function, but a conventionally known function other than the quadratic function may be used as a method for performing the interpolation.
FIG. 11 is a schematic diagram showing the positional relationship between the maximum deflection point F (indicated by symbol ◯) in the step S22 and nine striking points D (indicated by symbol ●).
Step S22 is performed by the computer 30 executing the calculation program.
This step S22 corresponds to the maximum deflection point and maximum deflection amount calculation means 30G in FIG.

Next, the position of the maximum deflection point and the maximum deflection amount are output (step S24).
The output form of the position of the maximum deflection point and the maximum deflection amount is arbitrary.
For example, the image shown in FIG. 11, the XY coordinate value of the maximum deflection point F, and a numerical value indicating the maximum deflection amount are displayed and output on the display screen of the display 46.
Alternatively, an image similar to such a display screen is printed out by the printer 48.
Of course, the data of the position of the maximum deflection point and the data of the maximum deflection amount are arbitrarily stored in the recording medium via the disk device 40.
Step S24 is performed by the computer 30 executing the calculation program.
This step S24 corresponds to the output means 30H in FIG.

FIG. 12 is a comparison diagram between the calculated value of the position of the maximum deflection point and the actually measured value.
In FIG. 12, the distance from the center point C of the face surface 12 to the maximum deflection point in the crown direction of the face surface 12 and the distance from the center point C of the face surface 12 to the maximum deflection point in the toe direction of the face surface 12 are shown. Comparing.
In the figure, FEM (impact analysis) indicates a value calculated according to the present embodiment.
FEM (Eigenvalue Analysis) indicates a value obtained by obtaining the maximum deflection point by the finite element method under the condition that the face surface 12 is vibrated using the same golf club head model as in the present embodiment.
In the experiment, the face surface of an actually manufactured golf club head was vibrated in the vertical direction to vibrate the striking surface, and the vibration distribution (amplitude distribution) on the face surface was measured by a laser vibrometer placed at a position facing the face surface. Is a value obtained by measuring the position of the maximum deflection point.
As is apparent from FIG. 12, the FEM (impact analysis) value is closer to the experimental value than the FEM (eigenvalue analysis) value.

As explained above, according to the calculation method of the present embodiment, when the golf ball model 2A is hit with a plurality of hit points D set on the face surface 12 of the golf club head model 10A, Time series data of the amount of deflection generated is obtained by simulation of collision analysis by the finite element method. Then, the position of the maximum deflection point and the maximum deflection amount are obtained by performing calculation processing using these time series data.
Therefore, the position of the maximum deflection point and the maximum deflection amount can be accurately obtained in a short time and at a low cost without actually manufacturing a golf club head, which is advantageous in improving design efficiency.

(Second Embodiment)
Next, a second embodiment will be described.
In the first embodiment, the processing for calculating the narrowed average maximum deflection amount, that is, the case where Steps S16, S18, and S20 are performed once has been described.
On the other hand, in the second embodiment, the process of calculating the narrowed average maximum deflection amount is repeated twice or more, so that the area of the specific region is gradually reduced each time the process is repeated. Yes.
FIG. 13 is a flowchart of a calculation method according to the second embodiment.
Steps S30, S32, and S34 (S34A, S34B) are the same as steps S10, S12, and S14 (S14A and S14B) in FIG.

A first specific region including the maximum deflection point is determined based on the initial average maximum deflection amount calculated in step S34 (step S36: first specific region determination step).
In the second embodiment, as described with reference to FIG. 9, the first specific area is determined based on the magnitude relation of the initial average maximum deflection amount of each striking point D. Determine if the deflection point is located.
For example, the sum of the initial average maximum deflection amounts of the four hit points D located at the four vertices of each initial region is obtained, and the initial region A1 having the largest sum is determined as the specific region including the maximum deflection point. To do.

  Next, the first specific area is divided into a plurality of rectangular first small areas having the same shape and the same size, and the vertex of each first small area is set on the face surface 12 as a hit point (step S38: First small area dot setting step).

  Next, by performing the same processing as step S34 for the plurality of hit points set in step S38, the first narrowed average maximum deflection amount is calculated for each of the plurality of hit points (step S40: first narrowed average maximum deflection amount). Calculation step).

Next, a second specific region including the maximum deflection point is determined based on the first narrowed average maximum deflection amount (step S42: second specific region determination step).
This process is performed in the same manner as step S36.
That is, the determination of the second specific area determines in which of the first specific areas the maximum deflection point is located based on the magnitude relation of the first narrowed average maximum deflection amount of each hit point.
For example, the sum of the first narrowed average maximum deflection amounts of four striking points located at the four vertices of each first specific region is obtained, and the first specific region having the largest sum is determined as the maximum deflection point. Is determined as the second specific area.
Here, since the second specific region has the same area as the first small region obtained by dividing the first specific region, the area of the second specific region is smaller than the area of the first specific region.

  Next, the second specific area is divided into a plurality of second small areas having the same shape and the same size, and the vertex of each second small area is set as a new hitting point on the face surface (step S44). : Second small area dot setting step).

  By performing the same process as step S40 for a plurality of new hit points set in step S44, a second narrowed average maximum deflection amount is calculated for each of the multiple new hit points (step S46: second narrowed average maximum). Deflection amount calculation step).

  The position of the maximum deflection point and the maximum deflection amount are calculated by interpolation using the positions of the plurality of hit points and the second narrowed average maximum deflection amount (step S48: maximum deflection point and maximum deflection amount calculation step). .

  Finally, the position of the maximum deflection point and the maximum deflection amount are output (step S50: output step).

FIG. 14 is a functional block diagram illustrating a configuration of a computing device configured by the computer 30 in the second embodiment.
This calculation apparatus includes a model creation means 30A, an initial area hit point setting means 30B, an initial average maximum deflection amount calculation means 30C, a first specific area determining means 30I, a first small area hit point setting means 30J, First narrowed average maximum deflection amount calculating means K, second specific area determining means 30L, second small area hitting point setting means 30M, second narrowed average maximum deflection amount calculating means 30N, and maximum deflection point The maximum deflection amount calculation means 30G and the output means 30H are included.
Each of these means 30A to 30H is realized by the computer 30 executing a finite element analysis program and a calculation program, as in the first embodiment.
Each means 30A thru | or 30H is corresponded to step S30, S32, S34, S36, S38, S40, S42, S44, S46, S48, S50, respectively.

According to the second embodiment, the same effects as those of the first embodiment can be obtained.
Furthermore, according to the second embodiment, a series of processes for calculating the narrowed average maximum deflection amount is repeated twice. That is, a series of processes of steps S36, S38, and S40 and a series of processes of steps S42, S44, and S46 are performed.
Accordingly, the area of the second specific region is smaller than the area of the first specific region.
That is, the area of the specific region is gradually reduced every time the process of calculating the narrowed average maximum deflection amount is repeated.
Thus, reducing the area of the specific region step by step is advantageous in suppressing errors in calculating the position of the maximum deflection point and the maximum deflection amount.
Therefore, it is advantageous to ensure the accuracy of the calculated maximum deflection point position and maximum deflection amount.
Note that the number of repetitions of a series of processes for calculating the narrowed average maximum deflection amount may be three or more.

(Third embodiment)
Next, a third embodiment will be described.
The third embodiment obtains the following important data in designing a golf club by using the position of the maximum deflection point and the maximum deflection amount obtained in the first and second embodiments. .
1) The area of the sweet area where the initial velocity of the golf ball is equal to or greater than a predetermined threshold when the golf ball is hit with a golf club head.
2) A maximum initial velocity point that is a hitting point position on the face surface 12 at which the initial velocity of the golf ball becomes maximum when the golf ball hits the golf ball with the golf club head.

That is, the present inventors perform a finite element analysis using a golf club head model that is a finite element model of the golf club head 10, and the speed distribution of the face surface 12 during the swing of the golf club and the golf club head 10. It has been found that the positional relationship between the center of gravity of the golf club and the maximum deflection point of the face of the golf club head 10 greatly affects the area of the sweet area.
Then, in obtaining the above knowledge, by specifying the positional distribution of the speed distribution of the face surface 12, the barycentric point, and the maximum deflection point of the face and performing simulation by the finite element method, the area of the sweet area and It was found that the maximum initial speed point can be calculated.
The center-of-gravity point is a point obtained by projecting the position of the center of gravity of the golf club head 10 perpendicularly to the face surface 12.
The face maximum deflection point is a point at which the deflection amount is maximum.

  Below, the analysis of the golf club head 10 performed to obtain the above knowledge will be described first, and then the method of calculating the maximum initial speed point and the area of the sweet area will be described.

FIG. 15 is a flowchart showing the analysis procedure of the golf club head 10.
First, similarly to the first embodiment, a golf club head model and a golf ball model configured by a finite element model are set (step S100).

Next, using the golf club head model, the distribution of the speed of the face surface 12 (hereinafter referred to as the face speed) is obtained by calculation, and the distribution of the face speed is set on the face surface 12 (step S102).
Here, the speed distribution means the distribution of the face speed immediately before hitting when the player hits a golf ball with the golf club having the golf club head 10 shown in FIG.
The speed distribution is mainly determined from a component depending on the length of the shaft 28 and a component due to rolling of the golf club head 10 (rotation around the shaft 28).
As shown in FIG. 16, the component depending on the length of the former shaft 28 is maximized at a point A at which the perpendicular of the extension line L of the central axis of the shaft 28 contacts the sole portion 18 of the golf club head 10.
The latter component that depends on the rolling of the golf club head 10 is maximized at a point B (the end portion on the toe 24 side of the golf club head 10) that is farthest from the extension line L of the central axis of the shaft 28.

Accordingly, the face speed is distributed so as to gradually increase from the upper part a on the heel 22 side to the lower part g on the toe 24 side of the face surface 12, as shown in FIG. In FIG. 17, contour lines v are shown for every 0.5 m / s speed.
Here, the contour line v of the speed distribution is a line connecting points of the same face speed on the face surface 12 in order to show the distribution of the face speed.
In the following, the length of the shaft 28 and the rolling size of the golf club head 10 are set to the length of the shaft 28 in the average golf club and the rolling size of the golf club head 10 in the average golf club. To analyze.

  Next, as shown in FIG. 18, the center of gravity P is arranged at the center point of the face surface 12 (step S104).

Next, as shown in FIG. 18, a face maximum deflection point Q is temporarily arranged along a circumference E centered on the center of gravity P (step S106). Then, as shown in FIG. 18, a face deflection distribution R around the maximum deflection point Q of the face is temporarily set (step S108). In this example, the case where the face maximum deflection point Q is arranged along the circumference E centered on the center of gravity P will be described. However, the arrangement of the face maximum deflection point Q is not limited to this. .
Examples of the shape of the face deflection distribution R include a shape having concentric and equispaced contour lines with respect to the maximum deflection point Q of the face. Here, the contour line of the face deflection distribution R is a line connecting points of the same deflection amount on the face surface 12 in order to show the deflection distribution of the face surface 12.

  Then, the golf club head 10 calculates an initial velocity (ball initial velocity) of the golf ball when the golf club head 10 collides with the golf ball at the hit point D on the face surface 12 at a predetermined head speed H, and the hit point D on the face surface 12 is calculated. The position and the initial ball speed at the hit point D are associated with each other and stored in a storage means such as the RAM 36 shown in FIG. 2 (step S110). Here, the initial velocity of the ball is obtained by simulation of collision analysis by the finite element method.

Next, the position of the hit point D on the face surface 12 is changed (step S112), and the process returns to step S110 to repeat the same processing.
In this example, the positions of the hit points D to be changed are predetermined at a plurality of positions so as to be distributed over the entire face surface 12, and the number of hit points D is 49.

If the initial ball speeds are obtained for all the hit points D, the initial ball speeds are compared with a predetermined threshold value c, and the distribution of hit points D at which the initial ball speed is equal to or higher than the threshold value c, that is, the position of the sweet area The area is acquired, and the position and area of the sweet area are stored in storage means such as the RAM 36 (step S114).
As a result, if the distribution of the hit points D at which the ball initial velocity corresponding to the single maximum deflection point Q temporarily arranged in step S106 is equal to or greater than the threshold value c is obtained, the position of the maximum deflection point Q is determined on the circumference E. (Step S116).
Then, a face deflection distribution R is set corresponding to the face maximum deflection point Q arranged in step S116 (step S118).
Next, the process proceeds to step S110 and the same processing is repeated.

Here, a description will be given with reference to FIG.
FIG. 19 is an explanatory diagram showing the contour lines v of the speed distribution set on the face surface 12 of the golf club head model, the center of gravity point P, and the maximum deflection point Q of the face.
In FIG. 19, the horizontal axis indicates the horizontal coordinate position in mm when the face surface 12 of the golf club head model is viewed from the front, and the vertical axis is when the face surface 12 of the golf club head model is viewed from the front. The vertical coordinate position on the face surface 12 of the golf club head model is shown in mm.
The closer the horizontal coordinate position is to the left (negative direction), the closer to the toe 24 side, and the further the horizontal coordinate position is to the right (positive direction), the closer to the heel 22 side.
In other words, the horizontal axis indicates the position of the hit point D in the horizontal direction, and the vertical axis indicates the position of the hit point D in the vertical direction.

In this example, since the barycentric point P matches the center point of the face surface 12, the coordinate position of the barycentric point P is the origin (0 mm, 0 mm).
As shown in FIG. 6, the positional relationship between the face surface 12 and the horizontal and vertical axes is such that the angle formed by the extension line L of the central axis of the shaft 28 and the horizontal plane in the golf club head model is the lie angle of the shaft 28. It is shown in a state that matches.
In the figure, the numerical value attached to the contour line v indicating the speed distribution indicates the speed (m / s unit) of the contour line.
A symbol M indicates a straight line that passes through the center of gravity P and is orthogonal to the contour line v.
As shown in FIG. 19, in this example, the positions at which the face maximum deflection point Q is changed are determined in advance at six positions along the circumference E and one position that is the same as the center of gravity point P. The number of maximum face deflection points Q is seven.
Here, the radius of the circumference E is 7 mm.

  Returning to FIG. 15 and continuing the description, if the position and area of the sweet area are acquired for all the maximum deflection points Q of the face, the position of the maximum deflection point Q at which the sweet area area is maximized is determined ( Step S120), a series of analysis processing is terminated.

  By performing such an analysis process, the position of the face maximum deflection point Q at which the size of the sweet area determined by the threshold c is maximized is obtained.

In this example, the threshold value c for determining the sweet area is set to two types, a first threshold value c1 and a second threshold value c2. In the following, for easy understanding, the sweet area defined by the first threshold c1 is referred to as a high initial speed sweet area, and the sweet area defined by the second threshold c2 is referred to as a medium initial speed sweet area.
First threshold c1> second threshold c2
First threshold c1: Initial ball speed −1 m / s (high initial speed area 98%)
Second threshold c2: initial ball speed-3 m / s (medium initial speed area 95%)
However, the maximum ball initial speed (100%): 58.5 m / s (head speed 40 m / s)

First, the case where a high initial speed sweet area is realized by setting the threshold value c to the first threshold value c1 will be described.
FIG. 20 is an explanatory diagram showing an analysis result when the threshold c is set to the first threshold c1.
In FIG. 20, the seven largest face deflection points Q are assigned the first to seventh ranks according to the size of the area of the high initial velocity sweet area. In other words, the first largest face deflection point Q has the largest area of the high initial velocity sweet area, and the seventh largest face deflection point Q has the smallest area of the high initial velocity sweet area.
As is clear from FIG. 20, when the face speed of the maximum deflection point Q is the highest, the area of the high initial velocity sweet area is the maximum (first place), and the face speed of the maximum deflection point Q is the lowest. In addition, the area of the high initial velocity sweet area is the smallest (seventh place).
In this case, the 1st and 7th face maximum deflection points Q are located on the straight line M.
When the area of the high initial velocity sweet area at the 1st face maximum deflection point Q is 100%, the area of the 2nd to 7th high initial velocity sweet area is as follows.
1st place: 100%
2nd place: 97%
3rd place: 86%
4th place: 85%
5th place: 74%
6th place: 51%
7th place: 50%

The following was found from FIG.
When the threshold value c is the first threshold value c1, the case where the face speed at the face maximum deflection point Q is higher than the case where the face speed is low is advantageous in securing a large size of the high initial speed sweet area.
In addition, if the face speed at the face maximum deflection point Q is higher than the face speed at the center of gravity point P, it is advantageous in securing a large size of the high initial speed sweet area.
Further, when the face surface 12 is divided into four regions by a horizontal axis and a vertical axis passing through the center of gravity P, it is on the toe side from the center of gravity P in the horizontal direction and below the center of gravity P in the vertical direction. Arranging the face maximum deflection point Q in the region located on the side is advantageous in securing a large size of the high initial speed sweet area.

21 and 22 are schematic diagrams showing the relationship among the center of gravity point P, the face maximum deflection point Q, the face speed Vf, and the initial ball speed.
21 and 22, the horizontal axis indicates the straight line M in FIG. 20, and the left side in the figure is the toe side and the right side is the heel side. The vertical axis indicates the ball initial speed, and the ball initial speed increases as it goes upward.
The initial ball speed at a certain hitting point D is considered to be determined by the contribution of three factors: the face speed Vf, the position of the maximum deflection point Q of the face, and the position of the center of gravity P.
That is, the higher the face speed Vf at the hit point D, the higher the ball initial speed.
Further, the closer the center of gravity P is to the hit point D, the higher the ball initial speed becomes.
Further, the closer the face maximum deflection point Q is to the hit point D, the higher the ball initial speed becomes.
That is, as shown in FIG. 21 and FIG. 22, the initial ball velocity at a certain hit point D includes a component contributed by the face speed Vf, a component contributed by the position of the face maximum deflection point Q (face deflection distribution R), and the barycentric point. It is considered that the value is determined by adding the components to which the position of P contributes.

Therefore, as shown in FIG. 22, if the face speed at the maximum deflection point Q is lower than the face speed Vf at the center of gravity P, it is disadvantageous in securing a large size of the high initial speed sweet area.
On the other hand, as shown in FIG. 21, if the face speed at the maximum deflection point Q of the face is higher than the face speed Vf at the center of gravity P, it is advantageous in securing a large size of the high initial speed sweet area. Become.
In this case, the higher the face speed at the face maximum deflection point Q, the more advantageous in securing a large size of the high initial speed sweet area. That is, as shown in FIG. 23, when the maximum face speed point Vfmax and the face maximum deflection point Q are matched, the high initial speed sweet area is maximized.
Note that the positions of the gravity center point P and the maximum face deflection point Q on the face surface 12 are limited by the design of the golf club head 10, and therefore there is an upper limit on the size of the high initial velocity sweet area.

Next, a case where the medium initial speed sweet area is realized by setting the threshold value c to the second threshold value c2 will be described.
FIG. 24 is an explanatory diagram showing an analysis result when the threshold value c is set to the second threshold value c2.
In FIG. 24, the seven face maximum deflection points Q are assigned the first to seventh ranks according to the size of the area of the medium initial speed sweet area. In other words, the first largest face deflection point Q has the largest medium initial velocity sweet area, and the seventh largest face deflection point Q has the smallest medium initial velocity sweet area.
As is clear from FIG. 24, when the face speed of the face maximum deflection point Q is the lowest, the area of the medium initial velocity sweet area is the maximum (first place), and the face speed of the face maximum deflection point Q is the highest. In addition, the area of the medium initial speed sweet area is close to the minimum (sixth place).
In this case, the 1st and 6th face maximum deflection points Q are located on the straight line M.
When the area of the medium initial speed sweet area at the 1st largest face deflection point Q is 100%, the area of the 2nd to 7th medium initial speed sweet area is as follows.
1st place: 100%
2nd place: 99.9%
3rd place: 98.8%
4th place: 97.8%
5th place: 94.8%
6th place: 92.2%
7th place: 91.9%

The following findings were obtained from FIG.
When the threshold value c is set to the second threshold value c2, the case where the face speed at the face maximum deflection point Q is lower than the case where the face speed is high is advantageous in securing a large size of the medium initial speed sweet area.
Further, if the face speed at the face maximum deflection point Q is lower than the face speed at the center of gravity point P, it is advantageous in securing a large size of the medium initial speed sweet area.
Further, when the face surface 12 is divided into four regions by a horizontal axis and a vertical axis passing through the center of gravity P, the heel side is higher than the center of gravity P in the horizontal direction and above the center of gravity P in the vertical direction. Disposing the face maximum deflection point Q in the region located in the position is advantageous in securing a large size of the medium initial speed sweet area.

25 and 26 are schematic diagrams showing the relationship among the center of gravity point P, the face maximum deflection point Q, the face speed Vf, and the initial ball speed.
As in the case of FIG. 21 and FIG. 22, the initial ball speed at a certain hit point D includes the component contributed by the face speed Vf, the component contributed by the position of the maximum deflection point Q (distribution of deflection), and the center of gravity P This is considered to be determined by a value obtained by adding the components to which the position contributes.
Therefore, as shown in FIG. 25, if the face speed at the maximum deflection point Q is higher than the face speed Vf at the center of gravity P, it is disadvantageous in securing a large size of the medium initial speed sweet area.
On the other hand, as shown in FIG. 26, if the face speed at the face maximum deflection point Q is lower than the face speed Vf at the center of gravity P, it is advantageous in securing a large size of the medium initial speed sweet area. Become.
In this case, the lower the face speed at the face maximum deflection point Q, the more advantageous it is to secure a large size of the medium initial speed sweet area. That is, as shown in FIG. 27, when the minimum face speed point Vfmin and the face maximum deflection point Q are matched, the medium initial speed sweet area is maximized.
As in the case of realizing the high initial speed sweet area, the positions of the center of gravity P and the face maximum deflection point Q on the face surface 12 are restricted by the design of the golf club head 10, so There is also an upper limit on the size.

The above analysis results are summarized as follows.
As is clear from FIGS. 25 and 26, the higher the threshold c that defines the sweet area, the wider the high initial speed area (the area where the maximum ball speed value is 100 and a ball speed of 98% or more can appear). be able to.
Further, the lower the threshold value c defining the sweet area, the wider the medium initial speed area (the area where the maximum ball speed value is 100 and a ball speed of 95% or more can appear).
Therefore, when expanding the high initial velocity area, as shown in FIG. 25, if the face speed at the maximum deflection point Q of the face is higher than the face speed at the center of gravity P, the face speed is higher than that shown in FIG. A large initial speed sweet area can be secured.
In addition, when the medium initial speed area is enlarged, as shown in FIG. 26, if the face speed at the maximum deflection point Q is lower than the face speed at the center of gravity point P, the medium initial speed area is medium compared to the case shown in FIG. A large initial speed sweet area can be secured.

As described in the process of obtaining such knowledge, the simulation is performed by the finite element method by specifying the positional distribution of the speed distribution of the face surface 12, the gravity center point, and the maximum deflection point of the face. The initial speed at each hit point D set to 12 can be calculated.
Therefore, of course, the area of the sweet area on the face surface 12 can be calculated, and the position of the hit point D that is the highest initial speed point among the hit points D can be obtained.

  Further, as described above, the area of the sweet area is greatly influenced by the positional relationship between the speed distribution of the face surface 12, the center of gravity of the golf club head 10, and the maximum deflection point of the face of the golf club head 10. In addition to the knowledge, the knowledge that the maximum initial speed point R is greatly influenced by the velocity distribution of the face surface 12 was obtained as described below.

First, the relationship among the gravity center point P, the maximum deflection point Q, and the maximum initial speed point R (the point on the face surface 12 at which the initial speed of the ball is the highest) when the speed distribution of the face surface 12 is not considered will be described.
FIG. 30 is a schematic diagram showing a positional relationship among the gravity center point P, the maximum deflection point Q, and the maximum initial speed point R when the velocity distribution of the face surface 12 is not considered.
It is considered that the initial ball speed at the hitting point of the face surface 12 is determined by a value obtained by adding the component contributed by the position of the center of gravity P and the component contributed by the position of the maximum deflection point Q.
In the figure, reference signs p1 and p2 indicate contour lines indicating a distribution indicating the component to which the position of the center of gravity P contributes, and the magnitude relationship between the contributing components is p1> p2.
Symbols q1 and q2 indicate contour lines indicating distributions indicating components to which the position of the maximum deflection point Q contributes, and the magnitude relationship between the contributing components is q1> q2.
Therefore, as shown in FIG. 30, the maximum initial speed point R is located on a substantially straight line LA connecting the center of gravity P and the maximum deflection point Q. However, the maximum initial speed point R may slightly deviate from the straight line LA depending on the head shape, the bulge of the face surface, the roll, and the like.
That is, when the velocity distribution of the face surface 12 is not taken into consideration, if the gravity center point P and the maximum deflection point Q are arranged so that the maximum initial velocity point R matches or is close to the center point C of the face surface 12, This is advantageous in increasing the sweet area and flight distance.

When the golfer swings the golf club and hits the golf ball with the face surface 12 of the golf club head 10, the velocity distribution (FIG. 17) of the face surface 12 is generated as described above.
The maximum initial speed point R is affected by such a face speed, and thus deviates from the position shown in FIG.
As shown in FIG. 31 (A), it is orthogonal to the contour line v (FIG. 17) indicating the velocity distribution of the face surface 12, in other words, connecting the points where the change amount of the face speed is maximum, and the maximum initial speed. A straight line L0 passing through the point R is assumed.
Then, as shown in FIG. 31 (B), the maximum initial speed point R is influenced by the velocity distribution of the face surface 12, and when the angle at which the straight line LA and the straight line L0 intersect is set to θ, the maximum initial speed point R is approximately θ. It moves in a direction along the angle (for example, about 3 to 5 mm). The angle θ varies depending on the deflection amount distribution and the face surface velocity distribution. Specifically, the maximum rebound point R moves closer to the toe 24 side and downward.
Further, as shown in FIG. 31C, the maximum initial speed point R moves further downward due to the influence of the face surface 12 being curved (R is given to the face surface 12). (For example, a total moving distance of about 6 to 10 mm).
As shown in FIG. 31 (C), the reason why the maximum initial speed point R moves further downward is as follows. That is, a curved surface (bulge) in the direction connecting the toe 24 and the heel 22 and a curved surface (roll) in the direction connecting the crown 4 and the heel 3 are formed on the face surface 12 of the normal wood head.
By forming such a curved surface on the face surface 12, the loft angle of the face surface 12 changes. As a result, the maximum initial speed point R moves downward. The amount of downward movement varies not only with the difference in the curved surface of the face surface 12, but also with the deflection amount distribution and the speed distribution of the face surface.
Therefore, when the golf club is actually swung and the ball is hit with the face surface 12, the position of the maximum initial speed point R is affected by the velocity distribution of the face surface 12 as described above, and FIG. The position is shifted closer to the toe side and lower than the position of the maximum rebound point R shown in FIG.
That is, it was found that the actual maximum initial speed point R is located at a position off the straight line LA connecting the center of gravity P and the maximum deflection point Q due to the influence of the velocity distribution of the face surface 12.
According to such knowledge, the position of the maximum deflection point Q and the maximum deflection amount obtained in the first and second embodiments are used, and the influence of the speed distribution of the face surface 12 is taken into consideration. By performing the simulation by the method, the position of the maximum initial speed point R on the face surface 12 can be calculated more accurately.

Hereinafter, a method for calculating the area of the sweet area and the maximum initial speed point will be described with reference to the flowchart shown in FIG.
Note that processing similar to that described in the flowchart of FIG. 15 will be briefly described.
First, similarly to the first embodiment, a golf club head model and a golf ball model, which are finite element models of the golf club head 10 and the golf ball, are created (step S200).
Next, the same processing as in the first and second embodiments is executed to calculate the position of the maximum deflection point and the maximum deflection amount (step S202). That is, the processing in steps S12 to S22 in FIG. 3 or steps S32 to S48 in FIG. 13 is executed.

Next, the face speed distribution is set on the face surface 12 (step S204).
Next, the barycentric point P is arranged on the face surface 12 (step S206). In this case, it is assumed that the barycentric point P is determined when the golf club head model is created.
Next, the face maximum deflection point Q is arranged at the position of the maximum deflection point calculated in step S202 (step S208).
Then, a face deflection amount distribution (face deflection distribution) R around the face maximum deflection point Q is set (step S210).
When setting the face deflection distribution R, the maximum deflection amount calculated in step S202 is used.
Further, examples of the shape of the face deflection distribution R include a shape having contour lines that are concentric with the face maximum deflection point Q and are equidistantly spaced.
Since the deflection amount and the coefficient of restitution are positively correlated, the coefficient of restitution can be converted from the amount of deflection. Therefore, the rebound distribution may be set by converting the deflection amount into a restitution coefficient.
Here, the coefficient of restitution is the value measured by the USGA (National Golf Association) COR measurement method (Procedure for Measuring the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999)). is there.

  Then, the golf club head 10 calculates an initial velocity (ball initial velocity) of the golf ball when the golf club head 10 collides with the golf ball at the hit point D on the face surface 12 at a predetermined head speed H, and the hit point D on the face surface 12 is calculated. The position and the initial ball speed at the hit point D are associated with each other and stored in a storage means such as the RAM 36 shown in FIG. 2 (step S212). The initial velocity of the ball is obtained by a collision analysis simulation by the finite element method.

Next, the position of the hit point D on the face surface 12 is changed (step S214), and the process returns to step S212 to repeat the same processing.
Here, the positions of the hit points D to be changed are predetermined at a plurality of positions so as to be distributed over the entire face surface 12.

  If the initial ball speeds are obtained for all the hit points D, the initial ball speeds are compared with a predetermined threshold value c, and the distribution of hit points D at which the initial ball speed is equal to or higher than the threshold value c, that is, the position of the sweet area The area is acquired, and the position and area of the sweet area are stored in storage means such as the RAM 36 (step S216).

Next, the hit point with the highest initial ball speed is selected from the initial ball speed and hit point position data stored in the storage means, and the position of the highest initial speed point is specified (step S218).
Finally, data on the area of the sweet area and the position of the maximum initial speed point are output (step S220).

That is, the third embodiment is a method for calculating the area of the sweet area and the position of the maximum initial speed point in the golf club head that further includes the following steps in addition to the first and second embodiments. .
1) A face surface speed distribution setting step for setting the speed distribution of the face surface immediately before the face surface of the golf club head of the swinged golf club hits the golf ball to the face surface of the golf club head model (corresponding to step S204). .
2) A centroid point setting step (corresponding to step S206) of setting a centroid point obtained by projecting the centroid position of the golf club head perpendicularly to the face surface of the golf club head model on the face surface of the golf club head model.
3) A maximum deflection point and deflection amount distribution setting step for setting the position of the maximum deflection point and the maximum deflection amount on the face surface of the golf club head model (corresponding to steps S208 and S210).
Since the deflection amount and the coefficient of restitution are positively correlated, the coefficient of restitution can be converted from the amount of deflection. Therefore, the rebound distribution may be set by converting the deflection amount into a restitution coefficient.
4) Ball initial velocity distribution calculating step for obtaining the velocity distribution on the initial velocity face surface of the golf ball model hit by the face surface of the golf club head model by simulation of collision analysis by the finite element method (corresponding to steps S212, S214, and S216) .
5) A sweet area calculating step (corresponding to step S216) for calculating the area of the sweet area where the ball initial speed is equal to or greater than a predetermined threshold based on the velocity distribution
6) A maximum initial speed point calculating step (corresponding to step S218) for calculating the position of the maximum initial speed point at which the ball initial speed becomes the maximum value based on the speed distribution.

The third embodiment is configured by a computer 30 as shown in FIG. 29 in addition to the configuration of FIG. 4 of the first embodiment or the configuration of FIG. 14 of the second embodiment. The golf club head evaluation data calculation device further includes the following means.
That is, the following means is realized by the computer 30 executing a finite element analysis program and a dedicated calculation program.
Face surface speed distribution setting means 60A (corresponding to the face surface speed distribution setting step), barycentric point setting means 60B (corresponding to the barycentric point setting step), maximum deflection point and deflection amount distribution setting means 60C (maximum deflection point and deflection amount distribution) Equivalent to setting step), ball initial speed distribution calculating means 60D (corresponding to ball initial speed distribution calculating means), sweet area calculating means 60E (corresponding to sweet area calculating step), maximum initial speed calculating means 60F (corresponding to maximum initial speed point calculating) .

As described above, according to the third embodiment, the position of the maximum deflection point and the maximum deflection amount obtained in the first and second embodiments are set on the face surface of the golf club head model, The area of the sweet area and the maximum initial velocity point were calculated by calculating the velocity distribution on the face surface of the initial velocity of the golf ball model by the simulation of the collision analysis by the finite element method. In this case, since the deflection amount and the restitution coefficient have a positive correlation, the restitution coefficient can be converted from the deflection amount. Therefore, the rebound distribution may be set by converting the deflection amount into a restitution coefficient.
Therefore, without actually manufacturing a golf club head, in addition to the position of the maximum deflection point and the maximum deflection amount, the area of the sweet area and the maximum initial speed point can be accurately determined in a short time and at a low cost. This is advantageous for improving efficiency.

  2A: Golf ball model, 10A: Golf club head model, 12: Face surface, D1 to D9: RBI, A1, A2, A3, A4 ... Initial area, A10: Specific area, A101, A102, A103, A104... Small area.

Claims (8)

A calculation method for obtaining a position of a maximum deflection point and a maximum deflection amount on a face surface of a golf club head,
An initial region in which a face surface of a golf club head model configured by a finite element model is divided into a plurality of rectangular initial regions of the same shape and the same size and set on the face surface with the vertex of each initial region as a hit point Dotting point setting step,
When a golf ball model composed of a finite element model is hit with one of the plurality of hit points, the time series data of the amount of deflection generated at each of the plurality of hit points is obtained by a simulation of collision analysis by the finite element method. An initial average maximum deflection amount calculating step of calculating an average value of peak values of the respective time series data as an initial average maximum deflection amount corresponding to the one hit point, and executing the process for all of the plurality of hit points. When,
A specific area determining step for determining a specific area including the maximum deflection point based on the initial average maximum deflection amount;
Dividing the specific area into a plurality of rectangular small areas of the same shape and the same size, and setting a small area hitting point on the face surface with the vertex of each small area as a hitting point;
Narrowed average maximum deflection amount calculating step for calculating a reduced average maximum deflection amount for each of a plurality of hit points by performing the same processing as the initial average maximum deflection amount calculating step for a plurality of hit points set in the small area hit point setting step. When,
A maximum deflection point and a maximum deflection amount calculating step for calculating the position of the maximum deflection point and the maximum deflection amount by interpolation using the positions of the plurality of hit points and the narrowed average maximum deflection amount;
A method of calculating a maximum deflection point and a maximum deflection amount in a golf club head characterized by the above. The division of the face surface into the plurality of initial regions by the initial region hitting point setting step is performed from the toe side to the heel side of the face surface of the golf club head model with the golf club head model set according to the lie angle. When the horizontal direction is X direction and the vertically upward direction is Y direction, a plurality of horizontal lines extending in parallel to the X direction with an interval in the Y direction, and a Y direction with an interval in the X direction The face surface is divided by a plurality of vertical lines extending in parallel.
The method of calculating the maximum deflection point and the maximum deflection amount in the golf club head according to claim 1. The division of the determined initial region into the plurality of small regions by the small region hitting point setting step includes a plurality of horizontal lines extending in parallel with the X direction and spaced in the Y direction, and spaced in the X direction. In this case, the determined initial region is divided by a plurality of vertical lines extending in parallel with the Y direction.
The method of calculating the maximum deflection point and the maximum deflection amount in the golf club head according to claim 2. The determination of the specific area by the specific area determination step is:
It is made by determining the initial region where the sum of the initial average maximum deflection amounts at the hit points corresponding to the four vertices of the initial region is the maximum as the specific region.
4. The method for calculating a maximum deflection point and a maximum deflection amount in a golf club head according to any one of claims 1 to 3. The determination of the specific area by the specific area determination step is:
An initial region having a maximum sum of initial average maximum deflection amounts at hit points corresponding to the four vertices of the initial region is selected, and a region having a smaller area than the initial region is selected as the specific region from the selected initial region Made by deciding,
The determination of the specific area is made based on an initial average maximum deflection amount at hit points corresponding to four vertices of the selected initial area.
5. The method for calculating a maximum deflection point and a maximum deflection amount in a golf club head according to any one of claims 1 to 4. The interpolation in the maximum deflection point and maximum deflection amount calculating step is performed using a quadratic function.
The method for calculating a maximum deflection point and a maximum deflection amount in a golf club head according to any one of claims 1 to 5. The golf club head is
A wall-like face portion constituting the face surface;
A wall-shaped crown portion connected to the face portion;
A wall-shaped sole portion connected to the face portion and the crown portion;
A hollow structure provided with a side part connected to the crown part and the sole part and facing the face part;
The golf club head model is composed only of a finite element model of the face part,
The method for calculating a maximum deflection point and a maximum deflection amount in a golf club head according to any one of claims 1 to 6. A calculation method for obtaining a position of a maximum deflection point and a maximum deflection amount on a face surface of a golf club head,
An initial region in which a face surface of a golf club head model configured by a finite element model is divided into a plurality of rectangular initial regions of the same shape and the same size and set on the face surface with the vertex of each initial region as a hit point Dotting point setting step,
When a golf ball model composed of a finite element model is hit with one of the plurality of hit points, the time series data of the amount of deflection generated at each of the plurality of hit points is obtained by a simulation of collision analysis by the finite element method. An initial average maximum deflection amount calculating step of calculating an average value of peak values of the respective time series data as an initial average maximum deflection amount corresponding to the one hit point, and executing the process for all of the plurality of hit points. When,
A first specific region determining step for determining a specific region including a maximum deflection point based on the initial average maximum deflection amount;
Dividing the specific region into a plurality of rectangular small regions of the same shape and size, and a first small region hitting point setting step for setting the vertex of each small region as a hitting point on the face surface;
A first narrowing-down process for calculating a narrowed-down average maximum deflection amount for each of a plurality of hit points by performing the same processing as the initial average maximum deflection amount calculating step for a plurality of hit points set in the first small area hit point setting step. An average maximum deflection amount calculating step;
A second specific area determining step for determining a new specific area including the maximum deflection point based on the narrowed average maximum deflection amount;
A second small area hit point setting that divides the new specific area into a plurality of new small areas of the same shape and the same rectangular shape, and sets the vertex of each small area as a new hit point on the face surface. Steps,
By performing the same process as the initial average maximum deflection calculation step for a plurality of new hit points set in the second small area hit point setting step, a new narrowed average maximum deflection amount is obtained for each of the plurality of new hit points. A second narrowed average maximum deflection calculation step to calculate;
A maximum deflection point and a maximum deflection amount calculating step for calculating a position of the maximum deflection point and a maximum deflection amount by interpolation using the positions of the plurality of hit points and the narrowed average maximum deflection amount;
After the second specific area determining step, the second small area hitting point setting step, and the second narrowed average maximum deflection amount calculating step are repeated once or twice or more, the maximum deflection point And executing a maximum deflection calculation step,
A method of calculating a maximum deflection point and a maximum deflection amount in a golf club head characterized by the above.

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