JP2021023724A - Specification determination method of badminton racket and analysis method of shaft behavior - Google Patents

Abstract

To provide a specification determination method for obtaining a badminton racket suitable to a specific player or a specific shot.SOLUTION: A determination method according to the present invention comprises the steps of: imaging the bending of a shaft in a shot by a standard racket (STEP 1); analyzing the way of bending of the shaft on the basis of the captured image (STEP 2); determining the characteristics of a target shaft on the basis of the obtained way of bending of the shaft (STEP 3); and selecting the racket attached with the shaft having the determined characteristics from ready-made rackets (STEP 4).SELECTED DRAWING: Figure 12

Description

The present invention relates to a method for determining specifications of a badminton racket. Specifically, the present invention relates to a method for determining the characteristics of a shaft that is a component of a racket.

The badminton racket has a frame, a string and a shaft. The player shoots the shuttle with a racket. At the time of shot, the shaft is deformed. The deformation behavior of the shaft affects the behavior of the shuttle. The characteristics of the shaft affect the quality of the shot.

Japanese Unexamined Patent Publication No. 2012-147846 discloses a shaft having an appropriate degree of flexibility and an appropriate degree of rigidity.

Japanese Unexamined Patent Publication No. 2012-147846

In a badminton game, players make different types of shots. For example, the player makes shots such as smash, lobing, and cut.

There are players who like powerful shots. Some players prefer controlled shots.

In a badminton doubles game, avant-garde players and rearguard players form a pair. The shots that are mainly required of avant-garde players and the shots that are mainly required of rearguard players are different.

There is a demand for a shaft with specifications suitable for shots preferred by players. There is also a demand for a shaft with specifications suitable for shots that are frequently used by players.

An object of the present invention is to provide a specification determination method for obtaining a badminton racket suitable for a specific player or a specific shot.

The method for determining the specifications of the badminton racket according to the present invention is as follows.
It includes (A) a step of analyzing how the shaft bends in a shot and (B) a step of determining the characteristics of the target shaft based on the analysis result of the above step (A).

Preferably, in step (A), the bending method is determined by the bending amount of the shaft.

Preferably, in step (A), the bending method is determined by the maximum bending amount of the shaft.

Preferably, in step (A), the bending method is determined by the bending amount of the shaft in the in-plane direction and the bending amount of the shaft in the out-of-plane direction.

Preferably, in step (A), the bending method is determined by the maximum bending amount of the shaft in the in-plane direction and the maximum bending amount of the shaft in the out-of-plane direction.

Preferably, in step (A), the bending method is determined by the ratio of the bending amount of the shaft in the in-plane direction to the bending amount of the shaft in the out-of-plane direction.

Preferably, the property determined in step (B) is the rigidity of the shaft.

Preferably, the characteristic determined in step (B) is the stiffness distribution of the shaft.

Preferably, the properties determined in step (B) are the stiffness of the shaft in the in-plane direction and the stiffness of the shaft in the out-of-plane direction.

Preferably, the characteristics determined in step (B) are the rigidity distribution of the shaft in the in-plane direction and the rigidity distribution of the shaft in the out-of-plane direction.

According to another viewpoint, the method for manufacturing a badminton racket according to the present invention is:
(A) Steps to analyze how the shaft bends in a shot,
(B) A step of determining the characteristics of the target shaft based on the analysis result of the above step (A), and (C) A step of attaching the frame and the grip to the shaft having the characteristics determined by the above step (B). including.

According to still another viewpoint, the method for analyzing the shaft behavior of the badminton racket according to the present invention is as follows.
(A) Steps to measure the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction in the shot, and (B) The amount of bending of the shaft in the in-plane direction and the out-of-plane direction. Includes a step to compare the amount of bending of the shaft.

By the determination method according to the present invention, a badminton racket suitable for a specific player can be obtained. By the determination method according to the present invention, a badminton racket suitable for a specific shot can be obtained.

FIG. 1 is a front view showing a badminton racket obtained by the determination method according to the embodiment of the present invention. FIG. 2 is a right side view showing the racket of FIG. FIG. 3 is a graph showing the results of a three-point flexural rigidity test of a standard racket shaft. FIG. 4 is a graph showing the measurement result of the amount of bending of the shaft of the standard racket at the time of smashing. FIG. 5 is a front view showing a state in which the racket of FIG. 1 is curved. FIG. 6 is a right side view showing a state in which the racket of FIG. 1 is curved. FIG. 7 is a graph showing the results of a three-point flexural rigidity test on the shafts of other rackets. FIG. 8 is a graph showing the measurement results of the amount of bending of the shaft of the standard racket during lobing. FIG. 9 is a graph showing the results of a three-point flexural rigidity test of the shaft of another racket. FIG. 10 is a graph showing the measurement results of the amount of bending of the shaft of the standard racket at the time of cutting. FIG. 11 is a graph showing the results of a three-point flexural rigidity test of the shaft of another racket. FIG. 12 is a flowchart showing a specification determination method according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

The badminton racket 2 is shown in FIGS. 1 and 2. The racket 2 has a shaft 4, a frame 6, a grip 8, and a string 10. In FIGS. 1 and 2, the arrow X represents the width direction, the arrow Y represents the axial direction, and the arrow Z represents the thickness direction.

The shaft 4 is hollow. The shaft 4 is made of a fiber reinforced resin. In this fiber reinforced resin, a base resin is impregnated in a large number of reinforcing fibers.

As the base resin of the shaft 4, thermocurable resins such as epoxy resin, pismareimide resin, polyimide and phenol resin; and polyetheretherketone, polyethersulfon, polyetherimide, polyphenylene sulfide, polyamide and polypropylene. Thermoplastic resin is exemplified. A resin particularly suitable for the shaft 4 is an epoxy resin.

Examples of the reinforcing fibers of the shaft 4 include carbon fibers, metal fibers, glass fibers and aramid fibers. A fiber particularly suitable for the shaft 4 is carbon fiber. Multiple types of fibers may be used in combination.

The frame 6 is annular and hollow. The frame 6 is made of a fiber reinforced resin. As the base resin of the fiber reinforced resin, a resin similar to the base resin of the shaft 4 can be used. As the reinforcing fiber of this fiber reinforced resin, the same resin as the reinforcing fiber of the shaft 4 can be used. The frame 6 is tightly coupled to the front end of the shaft 4.

The grip 8 has a hole (not shown) extending in the axial direction (Y direction). The vicinity of the rear end of the shaft 4 is inserted into this hole. The inner peripheral surface of the hole and the outer peripheral surface of the shaft 4 are joined with an adhesive.

The string 10 is stretched on the frame 6. The string 10 is stretched along the width direction X and the axial direction Y. The portion of the string 10 extending along the width direction X is referred to as a horizontal string. The portion of the string 10 extending along the axial direction Y is referred to as a vertical string. The face 12 (see FIG. 2) is formed by the plurality of horizontal strings and the plurality of vertical strings. The face 12 is generally along the XY plane.

In the design method according to the present invention, a standard racket is first prepared. This standard racket has a shaft. FIG. 3 shows the results of the three-point flexural rigidity test of this shaft. In the present embodiment, the measurement point of the flexural rigidity is 4. This shaft has a substantially flat stiffness distribution from the vicinity of the grip to the front end. A shaft with a non-flat stiffness distribution may be employed in the standard racket. Shafts of various specifications can be used in standard rackets. The racket that the player uses on a daily basis may be a standard racket.

[smash]
This standard racket was used by one player, and the bending of the shaft during smashing was photographed with an infrared camera. From the obtained image, the amount of bending of the shaft during the shot was measured. In this embodiment, the amount of bending of the shaft from the start of the shot to the end of the impact with the shuttle was measured. The result is shown in FIG. In FIG. 4, the solid line is the amount of bending in the in-plane direction, and the dotted line is the amount of bending in the out-of-plane direction. In the present embodiment, the amount of bending in the in-plane direction is the moving distance of the front end of the shaft in the X direction, and is indicated by the arrow Lx in FIG. In the present embodiment, the amount of bending in the out-of-plane direction is the moving distance of the front end of the shaft in the Z direction, and is indicated by the arrow Lz in FIG. The amount of bending in the in-plane direction and the out-of-plane direction may be measured at a predetermined position of the shaft other than the front end.

The behavior of the shaft is analyzed based on the amount of bending in the in-plane direction and the amount of bending in the out-of-plane direction. From FIG. 4, it can be seen that in the smash of this player, the shaft becomes larger in the in-plane direction and also becomes larger in the out-of-plane direction. The ratio R1 of the maximum amount of bending in the in-plane direction to the maximum amount of bending in the out-of-plane direction is 0.76.

I had this player use another racket. The rigidity distribution of the shaft of this racket is shown in FIG. This shaft has a front-down stiffness distribution. The behavior of the shuttle after smashing with this racket was photographed with a high-speed camera. From the obtained image, the speed of the shuttle when crossing the net was measured. The results are as follows.

Standard racket (rigidity distribution: flat)
Average speed: 23.9m / s
Maximum speed: 26.6m / s
Minimum speed: 21.0m / s
Variation: 5.6 m / s
Other racket (rigidity distribution: falling forward)
Average speed: 24.5m / s
Maximum speed: 25.7 m / s
Minimum speed: 23.9 m / s
Variation: 1.8 m / s

In a smash using a racket including a shaft having a front-down rigidity distribution, the average speed is high and the variation in speed is small. From this result, it can be seen that a racket including a shaft having a front-down rigidity distribution is suitable for the smash of this player.

Even in shots other than smash by this player, the shaft can be enlarged in both the in-plane direction and the out-of-plane direction. For example, the ratio R1 can be 1/2 or more and 2/1 or less. It is presumed that a shaft having a downward-sloping rigidity distribution is suitable for such a shot.

Shots by other players can also result in larger shafts in both in-plane and out-of-plane directions. For example, the ratio R1 can be 1/2 or more and less than 2/1. It is presumed that a shaft having a downward-sloping rigidity distribution is suitable for such a shot.

It is presumed that a shaft having a front-down rigidity distribution is suitable for a player who frequently uses shots in which the shaft becomes large in both the in-plane direction and the out-of-plane direction. It is presumed that a shaft having a front-down rigidity distribution is also suitable for a player who emphasizes a shot in which the shaft becomes large in both the in-plane direction and the out-of-plane direction.

[Robbing]
The above-mentioned standard racket was used by one player, and the bending of the shaft during lobing was photographed with an infrared camera. From the obtained image, the amount of bending of the shaft from the start of the shot to the end of the impact with the shuttle was measured. The result is shown in FIG. In FIG. 8, the solid line is the amount of bending in the in-plane direction, and the dotted line is the amount of bending in the out-of-plane direction.

As is clear from FIG. 8, in the lobing of this player, the shaft is not so much in the in-plane direction, but is large in the out-of-plane direction. The ratio R1 of the maximum amount of bending in the in-plane direction to the maximum amount of bending in the out-of-plane direction is 0.14.

I had this player use another racket. The rigidity distribution of the shaft of this racket is shown in FIG. This shaft has a downwardly convex stiffness distribution. The behavior of the shuttle after lobing using this racket was photographed with a high-speed camera. From the obtained image, the height of the shuttle when crossing the net was measured. The results are as follows.

Standard racket (rigidity distribution: flat)
Average height: 1.88m
Maximum height: 2.20m
Minimum height: 1.63m
Variation: 0.57m
Other racket (rigidity distribution: convex downward)
Average height: 1.85m
Maximum height: 1.97m
Minimum height: 1.80m
Variation: 0.17m

In lobing using a racket including a shaft having a downwardly convex rigidity distribution, the variation in the height of the shuttle is small. From this result, it can be seen that a racket including a shaft having a downwardly convex rigidity distribution is suitable for lobing of this player.

Even in shots other than lobing by this player, the shaft can be enlarged mainly in the out-of-plane direction. For example, the ratio R1 can be less than 1/2. It is presumed that a shaft having a downwardly convex rigidity distribution is suitable for such a shot.

Even in shots by other players, the shaft can be enlarged mainly in the out-of-plane direction. For example, the ratio R1 can be less than 1/2. It is presumed that a shaft having a downwardly convex rigidity distribution is suitable for such a shot.

It is presumed that a shaft having a downwardly convex rigidity distribution is suitable for a player who frequently uses shots in which the shaft becomes larger mainly in the out-of-plane direction. It is presumed that a shaft having a downwardly convex rigidity distribution is also suitable for a player who emphasizes a shot in which the shaft becomes larger mainly in the out-of-plane direction.

[cut]
The above-mentioned standard racket was used by one player, and the bending of the shaft at the time of cutting was photographed with an infrared camera. From the obtained image, the amount of bending of the shaft from the start of the shot to the end of the impact with the shuttle was measured. The result is shown in FIG. In FIG. 10, the solid line is the amount of bending in the in-plane direction, and the dotted line is the amount of bending in the out-of-plane direction.

As is clear from FIG. 10, in this player's cut, the shaft does not do much in the out-of-plane direction, but grows in the in-plane direction. The ratio R1 of the maximum amount of bending in the in-plane direction to the maximum amount of bending in the out-of-plane direction is 2.47.

I had this player use another racket. The rigidity distribution of the shaft of this racket is shown in FIG. This shaft has an upwardly convex stiffness distribution. The behavior of the shuttle after cutting with this racket was photographed with a high-speed camera. From the obtained image, the height of the shuttle when crossing the net was measured. The results are as follows.

Standard racket (rigidity distribution: flat)
Average height: 0.58m
Maximum height: 0.72m
Minimum height: 0.36m
Variation: 0.36m
Other racket (rigidity distribution: convex upward)
Average height: 0.50m
Maximum height: 0.55m
Minimum height: 0.45m
Variation: 0.10m

In the cut using a racket including a shaft having a convex rigidity distribution upward, the variation in the height of the shuttle is small. From this result, it can be seen that a racket containing a shaft having an upwardly convex rigidity distribution is suitable for cutting this player.

Even in shots other than cuts by this player, the shaft can be enlarged mainly in the in-plane direction. For example, the ratio R1 can be 2/1 or more. It is presumed that a shaft having an upwardly convex rigidity distribution is suitable for such a shot.

Even in shots by other players, the shaft can be enlarged mainly in the in-plane direction. For example, the ratio R1 can be 2/1 or more. It is presumed that a shaft having an upwardly convex rigidity distribution is suitable for such a shot.

It is presumed that a shaft having an upwardly convex rigidity distribution is suitable for a player who frequently uses shots in which the shaft becomes larger mainly in the in-plane direction. It is presumed that a shaft having an upwardly convex rigidity distribution is also suitable for players who place importance on shots in which the shaft becomes larger mainly in the in-plane direction.

[Determination of racket specifications]
FIG. 12 is a flowchart showing a specification determination method according to an embodiment of the present invention. In this determination method, first, the bending of the shaft is photographed in a shot with a standard racket (STEP 1). Typically, the shooting is done with an infrared camera. Motion control photography is typically performed. Shooting is done in shots that are frequently used by the player or shots that are emphasized by the player.

The bending of the shaft is analyzed based on the captured image (STEP2). Preferably, the maximum amount of bending of the shaft is measured from the start of the shot to the end of impact with the shuttle. Preferably, the amount of bending in the in-plane direction and the amount of bending in the out-of-plane direction are measured. Preferably, the ratio R1 of the maximum amount of bending in the in-plane direction to the maximum amount of bending in the out-of-plane direction is calculated.

The characteristics of the target shaft are determined based on how the obtained shaft bends (STEP 3). Examples of the characteristics include length, thickness, weight, mass distribution, rigidity, and rigidity distribution. Typically, the stiffness distribution of the target shaft is determined. The rigidity of the shaft in the in-plane direction and the rigidity of the shaft in the out-of-plane direction may be determined. The rigidity distribution of the shaft in the in-plane direction and the rigidity distribution of the shaft in the out-of-plane direction may be determined.

An example of a reference when the rigidity distribution of the target shaft is determined based on the ratio R1 of the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is shown below.
Ratio R1 is less than 1/2: Select a downwardly convex rigidity distribution Ratio R1 is 1/2 or more and less than 2/1: Select a front-down rigidity distribution Ratio R1 is 2/1 or more: Select an upwardly convex rigidity distribution Selection

A racket equipped with a shaft having the determined characteristics is selected from ready-made products (STEP 4). In this way, the specifications of the badminton racket are determined. The selected racket is suitable for the player. Players can use this racket to make highly accurate shots.

A frame and a grip may be attached to an existing shaft having the determined characteristics to manufacture a new racket. In other words, the present invention has the following viewpoints.
(A) Steps to analyze how the shaft bends in a shot,
(B) A step of determining the characteristics of the target shaft based on the analysis result of the above step (A) and (C) A step of mounting the frame and the grip on the shaft having the characteristics determined by the above step (B). How to make a badminton racket, including.

A shaft with the determined properties may be newly manufactured.

A useful use example of the specification determination method according to the present invention is customization. According to the present invention, the optimum badminton racket can be determined for each player.

The specification determination method according to the present invention can also contribute to the enhancement of the product lineup. For example
(1) Badminton racket suitable for players who prefer powerful shots (2) Badminton racket suitable for players who prefer controlled shots (3) Badminton racket suitable for doubles avant-garde players (4) Suitable for doubles rear guard players Badminton racket (5) Badminton racket suitable for players who place importance on serve (6) Badminton racket suitable for players who place importance on smash (7) Badminton racket suitable for players who place importance on receive may be commercially available.

A badminton racket suitable for an individual player can be selected by the specification determination method according to the present invention.

2 ... Badminton racket 4 ... Shaft 6 ... Frame 8 ... Grip 10 ... String 12 ... Face

Claims (12)

A method for determining the specifications of a badminton racket, which includes (A) a step of analyzing how the shaft bends in a shot and (B) a step of determining the characteristics of a target shaft based on the analysis result of the above step (A). The specification determination method according to claim 1, wherein in step (A), the method of bending is determined by the amount of bending of the shaft. The specification determination method according to claim 2, wherein in step (A), the bending method is determined by the maximum bending amount of the shaft. The specification determination method according to claim 1, wherein in the step (A), the bending method is determined by the bending amount of the shaft in the in-plane direction and the bending amount of the shaft in the out-of-plane direction. The specification determination method according to claim 4, wherein in step (A), the bending method is determined by the maximum bending amount of the shaft in the in-plane direction and the maximum bending amount of the shaft in the out-of-plane direction. The specification determination method according to claim 4 or 5, wherein in step (A), the bending method is determined by the ratio of the bending amount of the shaft in the in-plane direction to the bending amount of the shaft in the out-of-plane direction. The specification determination method according to any one of claims 1 to 6, wherein the characteristic determined in the step (B) is the rigidity of the shaft. The specification determination method according to any one of claims 1 to 6, wherein the characteristic determined in the step (B) is the rigidity distribution of the shaft. The specification determination method according to any one of claims 1 to 6, wherein the characteristic determined in the step (B) is the rigidity of the shaft in the in-plane direction and the rigidity of the shaft in the out-of-plane direction. The specification determination method according to any one of claims 1 to 6, wherein the characteristic determined in the step (B) is the rigidity distribution of the shaft in the in-plane direction and the rigidity distribution of the shaft in the out-of-plane direction. (A) Steps to analyze how the shaft bends in a shot,
(B) A step of determining the characteristics of the target shaft based on the analysis result of the above step (A), and (C) A step of attaching the frame and the grip to the shaft having the characteristics determined by the above step (B). How to make a badminton racket, including. (A) Steps to measure the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction in the shot, and (B) The amount of bending of the shaft in the in-plane direction and the out-of-plane direction. A method for analyzing the shaft behavior of a badminton racket, including a step of comparing the amount of bending of the shaft.

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