阅读说明：本技术 羽毛球 (Shuttlecock ) 是由 阪口巧 前田祥吾 于 2019-12-24 设计创作，主要内容包括：一种羽毛球1,包括基部2和以环形布置在基部2上的多个人造羽毛10,其中人造羽毛10各自具有羽毛部12和支撑羽毛部12的羽毛轴部14。当从与基部2相反的一侧观察,以羽毛球的中心轴线为中心的逆时针旋转方向作为旋转方向时,在羽毛轴部14的沿旋转方向的下游侧上,连接羽毛部12的沿旋转方向的下游端和羽毛轴部14的中心部分的假想直线M位于连接羽毛部12的沿旋转方向的上游端和羽毛轴部14的中心部分的假想直线N的外侧。(A shuttlecock 1 comprising a base 2 and a plurality of artificial feathers 10 arranged in a ring on the base 2, wherein the artificial feathers 10 each have a feather portion 12 and a feather shaft portion 14 supporting the feather portion 12. When the counterclockwise rotation direction about the central axis of the shuttlecock is taken as the rotation direction when viewed from the side opposite to the base 2, on the downstream side of the feather shaft 14 in the rotation direction, an imaginary straight line M connecting the downstream end of the feather portion 12 in the rotation direction and the central portion of the feather shaft 14 is located outside an imaginary straight line N connecting the upstream end of the feather portion 12 in the rotation direction and the central portion of the feather shaft 14.)

1. A shuttlecock, comprising:

a base; and

a plurality of artificial feathers arranged in a ring shape on the base,

the artificial feathers each comprise a feather portion and a feather shaft portion supporting the feather portion,

when the rotating direction is the counterclockwise direction with the central axis of the badminton as the center when the badminton is observed from the side opposite to the base,

on a downstream side of the feather shaft portion in the rotation direction, a first imaginary straight line is outward with respect to a second imaginary straight line,

the first imaginary straight line is a line connecting a downstream end of the feather portion in the rotation direction and a central portion of the feather shaft portion,

the second imaginary straight line is a line connecting an upstream end of the feather portion in the rotation direction and a central portion of the feather shaft portion.

2. The shuttlecock as in claim 1,

the feather portion includes an inclined portion at a position between a downstream end of the feather portion in the rotation direction and the feather shaft portion,

the inclined portion is a portion inclined outward with respect to the second imaginary straight line, an

When the feather portion is viewed from the extension of the feather shaft portion in the axial direction,

the length of the inclined portion is greater than a half of the length from the downstream end of the feather portion in the rotation direction to the feather shaft portion.

3. The shuttlecock as claimed in claim 1 or claim 2,

the feather portion includes an overlapping portion that overlaps with an inner side of an adjacent feather portion at a position on an upstream side of the feather shaft portion in the rotation direction, and

the overlapping portion of the feather portion is in contact with an adjacent feather portion.

4. The shuttlecock as claimed in claim 1 or claim 2,

the feather portion includes an overlapping portion that overlaps with an inner side of an adjacent feather portion at a position on an upstream side of the feather shaft portion in the rotation direction, and

the overlapping portion of the feather portions is not in contact with adjacent feather portions.

5. A shuttlecock, comprising:

a base; and

a plurality of artificial feathers arranged in a ring shape on the base,

the artificial feathers each comprise a feather portion and a feather shaft portion supporting the feather portion,

when the rotating direction is the counterclockwise direction with the central axis of the badminton as the center when the badminton is observed from the side opposite to the base,

the feather portion includes a protruding portion between a downstream end of the feather portion in the rotation direction and a position overlapping the feather shaft portion,

the projection is a portion projecting outward from the outer surface.

Technical Field

The present invention relates to shuttlecocks using artificial feathers.

Background

Shuttlecocks used for badminton games include shuttlecocks using waterfowl feathers (natural feathers) as feathers (i.e., natural shuttlecocks) and shuttlecocks using artificial feathers artificially manufactured by nylon resin or the like (i.e., artificial shuttlecocks).

As is well known, a natural shuttlecock uses about 16 natural feathers from geese, ducks and the like, and has a structure in which the bottom ends of feather shafts of the feathers are implanted in a semispherical base (base) made of cork and covered with leather. Feathers used in natural shuttlecocks are characterized by having a low specific gravity and extremely light weight. The feather is highly rigid and natural shuttlecocks provide unique flight characteristics and a comfortable feel to hit a ball.

On the other hand, a well-known example of an artificial shuttlecock is one provided with feathers made of resin and molded integrally into a ring shape, but since the feathers of such an artificial shuttlecock do not move independently like those of a natural shuttlecock, it is difficult to obtain flight performance similar to that of a natural shuttlecock.

In view of this, as described in the following patent document 1, artificial feathers that mimic natural feathers have been proposed. Specifically, a shuttlecock having artificial feathers including a feather portion and a feather shaft portion supporting the feather portion has been proposed.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2008-206970.

Disclosure of Invention

Problems to be solved by the invention

The flight stability of the shuttlecock having artificial feathers (artificial shuttlecock) as described above is still inferior to that of the natural shuttlecock. The main reason is that artificial feathers are denser and heavier than natural feathers and are unlikely to exhibit the same aerodynamic properties as natural feathers.

If the weight of the shaft (feather shaft portion) is reduced in order to reduce the weight of the artificial feather, the rigidity may not be sufficient to withstand a power hit ball such as a strike. On the other hand, if the area of the feather portion is reduced, the aerodynamic characteristics are further deteriorated.

Even if the total weight of the artificial shuttlecock is the same as that of the natural shuttlecock, the position of the center of gravity is different from that of the natural shuttlecock, and therefore, stability is deteriorated when the posture is out of balance (it takes time to return to the correct posture). In particular, in a "hairpin net shot" called a badminton hitting method, the difference in posture stability from a natural badminton is remarkable. A hairpin hitting ball is a technique of hitting a shuttlecock to float the shuttlecock in the air and to trace a unique flight trajectory. During the hitting of the hair pin net, the posture of the badminton is greatly unbalanced.

The present invention has been made in view of the above circumstances, and it is an aspect of the present invention to provide a shuttlecock capable of having improved aerodynamic characteristics for a shot involving a great loss of balance in posture.

Means for solving the problems

A main aspect of the invention for achieving the above object is a shuttlecock including a base and a plurality of artificial feathers arranged in a ring shape on the base, wherein the artificial feathers each include a feather portion and a feather shaft portion supporting the feather portion, wherein the feather portion includes an overlapping portion that overlaps with an inner side of an adjacent feather portion at a position on one side of the feather shaft portion in a width direction orthogonal to an axial direction, and wherein the feather portion includes an inclined portion inclined outward with respect to a surface of the overlapping portion at a position on the other side of the feather shaft portion in the width direction.

Other features of the present invention will become apparent from the description of the specification and the drawings.

Effects of the invention

According to the present invention, it is possible to provide a shuttlecock capable of having improved aerodynamic characteristics for a shot involving a large loss of balance in posture.

Drawings

Fig. 1 is a perspective view of an artificial shuttlecock 100 (comparative example) viewed from one side of a base 2.

Fig. 2 is a perspective view of the artificial feather 100 (comparative example) viewed from one side of the artificial feather 110.

Fig. 3A is a perspective view of artificial feather 110 of a comparative example. Fig. 3B is a schematic view of the artificial feather 110 viewed from above.

Fig. 4 is a schematic view of a plurality of artificial feathers 110 arranged on the artificial shuttlecock 100 of the comparative example, as viewed from above.

Fig. 5 is a schematic view of the artificial feather 10 of the first embodiment, viewed from above.

Fig. 6 is a schematic view of a plurality of artificial feathers 10 of the first embodiment arranged on the artificial shuttlecock 1 as viewed from above.

Fig. 7 is a graph showing the evaluation result of the resistance of the artificial shuttlecock 1.

Fig. 8 is a graph showing the evaluation result of the pitching moment of the artificial shuttlecock 1.

Fig. 9 is a diagram showing the evaluation results of the effect confirmation test.

Fig. 10A is a schematic view of the artificial feather 10A of the first modification viewed from above. Fig. 10B is a schematic view of a plurality of artificial feathers 10a arranged on the artificial shuttlecock 1 as viewed from above.

Fig. 11 is a schematic view of an artificial feather 10b of a second modification viewed from above.

Fig. 12 is a schematic view of an artificial feather 10c of a third modification viewed from above.

Fig. 13 is a schematic view of an artificial feather 10d of a fourth modification viewed from above.

FIG. 14 is a schematic view of the artificial feather 10' of the second embodiment, viewed from above.

Detailed Description

Summary of the invention

At least the following will become apparent from the description of the present specification and the accompanying drawings.

A shuttlecock is illustrated comprising: a base; and a plurality of artificial feathers arranged in a ring shape on the base, the artificial feathers each including a feather portion and a feather shaft portion supporting the feather portion, a first imaginary straight line being outward with respect to a second imaginary straight line on a downstream side of the feather shaft portion in the rotation direction when a counterclockwise direction centering on a central axis of the shuttlecock is taken as the rotation direction as viewed from a side opposite to the base, the first imaginary straight line being a line connecting a downstream end of the feather portion in the rotation direction and a central portion of the feather shaft portion, the second imaginary straight line being a straight line connecting an upstream end of the feather portion in the rotation direction and the central portion of the feather shaft portion.

According to this shuttlecock, the projected area at a high angle of attack (when the posture is out of balance) is large, and the drag and pitching moment can be increased. As a result, the aerodynamic characteristics of the ball hit with the out-of-balance posture (hairpin hitting) can be improved.

In such a shuttlecock, it is desirable that the feather portion includes an inclined portion at a position between a downstream end of the feather portion in the rotation direction and the feather shaft portion, the inclined portion being a portion inclined outward with respect to the second imaginary straight line, and a length of the inclined portion is greater than a half of a length from the downstream end of the feather portion in the rotation direction to the feather shaft portion when the feather portion is viewed from an extension of the feather shaft portion in the axial direction.

According to this shuttlecock, the projected area is larger, and therefore the aerodynamic characteristics can be further improved.

In this shuttlecock, it is acceptable that the feather portions include an overlapping portion that overlaps with the inside of the adjacent feather portion at a position on the upstream side of the feather shaft portion in the rotation direction, and that the overlapping portion of the feather portion is in contact with the adjacent feather portion.

According to this shuttlecock, the rotational motion around the central axis during normal flight (at a low angle of attack) can be easily suppressed.

In this shuttlecock, it is acceptable that the feather portions include an overlapping portion that overlaps with the inside of the adjacent feather portion at a position on the upstream side of the feather shaft portion in the rotation direction, and that the overlapping portion of the feather portion does not contact with the adjacent feather portion.

According to this badminton, can increase the inclination of inclined part to can further increase the projected area.

A shuttlecock is illustrated comprising: a base; and a plurality of artificial feathers arranged in a ring shape on the base, the artificial feathers each including a feather portion and a feather shaft portion supporting the feather portion, the feather portion including a projection between a downstream end of the feather portion in the rotation direction and a position overlapping the feather shaft portion when a counterclockwise direction centering on a central axis of the shuttlecock is taken as a rotation direction when viewed from a side opposite to the base, the projection being a portion projecting outward from an outer surface.

According to this shuttlecock, the aerodynamic characteristics can be improved for a ball hit with a largely unbalanced posture (a hairpin net ball hit).

First embodiment

Before a description of the artificial shuttlecock 1 of the present embodiment is given, a comparative example is first described below.

Basic structure of Artificial shuttlecock (comparative example)

Fig. 1 and 2 are external views for describing the basic structure of an artificial shuttlecock 100 provided with artificial feathers 110 according to a comparative example. Fig. 1 is a perspective view of an artificial shuttlecock 100 (comparative example) as viewed from the side of a base 2. Fig. 2 is a perspective view of the artificial shuttlecock 100 (comparative example) as viewed from one side of the artificial feather 110.

The artificial shuttlecock 100 includes a base 2, a plurality of artificial feathers 110 simulating natural feathers, and a string-like member 3 for fixing the artificial feathers 110 to each other. The base 2 is constituted, for example, by covering a cork base with thin leather. The base 2 is shaped in a hemispherical shape with a diameter of 25mm to 28mm and has a flat surface. The roots (bottom ends) of the artificial feathers 110 are embedded in the flat surface in a ring shape along the circumference of the flat surface. The artificial feathers 110 are arranged such that the distance between them becomes wider as the distance from the base 2 increases. Also, as shown, each artificial feather 110 is arranged to overlap with adjacent artificial feathers 110. As a result, skirt 4 is formed from artificial feather 110. The artificial feathers 110 are fixed to each other by the string-like member 3 (for example, cotton string).

During normal flight (at a low angle of attack described later), the artificial shuttlecock 100 is rotated in a predetermined direction (rotation direction) around the central axis of the shuttlecock. In the present embodiment, the rotation direction is a counterclockwise direction when viewed from the artificial feather 110 side (the side opposite to the base 2) in fig. 2, in other words, a clockwise direction when viewed from the base 2. Note that the central axis of the shuttlecock is an axis passing through the center of the ring formed by the artificial feathers (here, the artificial feathers 110) (in other words, the center of the skirt) and the center of the base.

Structure of artificial feather (comparative example)

Fig. 3A is a perspective view of artificial feather 110 of a comparative example, and fig. 3B is a schematic view of artificial feather 110 as viewed from above. In these figures, parts already described are denoted by the same reference numerals.

Artificial feather 110 includes a feather portion 120 and a feather shaft portion 14. The feather portion 120 is a portion corresponding to the pinna of the natural feather, and the feather shaft portion 14 is a portion corresponding to the shaft of the natural feather.

In these figures, a vertical direction (corresponding to an axial direction) is defined along the length direction of the feather shaft portion 14, and the side having the feather portion 120 is an upper side (top end) and the opposite side is a lower side (bottom end). Also, in these figures, the front and rear are defined based on the state in which the artificial feather 110 is attached to the base 2. Note that the front-rear direction corresponds to the normal direction of the feather portion 120, and the front and rear correspond to the outside and inside, respectively, in a state where the artificial feather 110 is arranged in a ring shape on the base 2. Also, in these figures, a left-right direction (a direction orthogonal to the vertical direction) is defined along the direction in which the feather portion 120 extends from the feather shaft portion 14. In the left-right direction, "right" means the right side and "left" means the left side when the front side (outer side) is viewed from the rear side (inner side). Note that the left-right direction will also be referred to as a width direction. Further, the right side corresponds to the upstream side in the rotation direction and the left side corresponds to the downstream side in the rotation direction with respect to the feather shaft portion 14. In the following, constituent elements may be described according to terms "upper", "lower", "left", "right", "front", and "rear" defined in the drawings.

The feather portion 120 is a member that mimics the shape of a pinna of a natural feather. For example, the feather portion 120 may be made of a nonwoven fabric or a resin. In the case of using a nonwoven fabric, a reinforcing film is formed on the surface to prevent the fibers of the nonwoven fabric from becoming loose during a ball strike. The reinforcing film may be formed by coating a resin, and various coating methods such as a dipping method, a spraying method, and a roll coating method may be employed. Note that the reinforcing film may be formed on one side or both sides of the feather portion 120. Also, the reinforcing film may be formed on the entire surface or a part of the surface of the feather portion 120. Further, the shape of the feather portion 120 is not limited to the shape shown in the drawings (the same applies to the feather portion 12 described later). For example, an elliptical shape may be used.

The feather shaft portion 14 is an elongated member that mimics the shape of the shaft of a natural feather, and is a member that supports the feather portion 120. The feather shaft portion 14 has: a feather support portion 14a for supporting a region from the upper edge of the feather portion 120 to the lower edge thereof; and a feather root 14b protruding from the feather portion 120. The feather root 14b is a portion corresponding to a feather of a natural feather (note that this is sometimes referred to as a stalk). The bottom end of the feather shaft portion 14 (the lower end of the feather root 14 b) is embedded in the base 2 and fixed to the base 2. On the other hand, the tip of the feather shaft portion 14 overlaps the upper end of the feather portion 12. Note that, in this example, the sectional shape of the feather shaft portion 14 is a quadrangle (rectangle), but the sectional shape is not limited thereto, and other shapes (circle, ellipse, polygon, etc.) may be used.

Also, the feather shaft portion 14 and the feather portion 120 may be separate bodies or may be integrated. For example, if resin is used as a material for the feather shaft portion 14 and the feather portion 120, the feather shaft portion 14 and the feather portion 120 may be integrally molded by injection molding using a mold. Further, by performing injection molding (two-component molding) using two materials (resins), the feather shaft portion 14 and the feather portion 120 can be integrally formed using different materials.

The feather portion 120 may be supported on the front side of the feather support portion 14a, or the feather portion 120 may be supported on the rear side of the feather support portion 14 a. Also, a configuration is possible in which the feather portion 120 is composed of two pieces, and the two feather portions 120 sandwich the feather support portion 14 a. Further, the feather portion 120 may be embedded within the feather support portion 14 a.

Fig. 4 is a schematic view of a comparative example of artificial feather 110 arranged on an artificial shuttlecock 100, viewed from above. As shown, the feathers 120 are arranged such that the feathers 120 overlap each other at slightly different angles. More specifically, the right end portion of each feather portion 120 overlaps the inside of the left end portion of the adjacent feather portion 120. This portion of the right end portion (the portion overlapping with the adjacent feather portion 120) will be referred to as an overlapping portion S. Also, in this example, each feather portion 120 (specifically, the end of the overlapping portion S) is in contact with the adjacent feather portion 120.

In the artificial shuttlecock 100 (comparative example) described above, the artificial feather 110 is heavier than the natural feather. If the feather shaft portion 14 is thinned and lightened, there may be a possibility that the rigidity is insufficient to withstand a strong impact such as a pinch, and if the area of the feather portion 120 is reduced, there may be a possibility that the aerodynamic characteristics are deteriorated. Even if the total weight of the artificial shuttlecock 100 is adjusted to match the total weight of the natural shuttlecock, it is difficult to match the center of gravity, and the center of gravity is located at the rear (away from the base 2) as compared with the natural shuttlecock. Therefore, when the posture is out of balance, the stability deteriorates.

In particular, in a hairpin net hitting a shuttlecock to float the shuttlecock in the air, since the posture is out of balance, the difference in posture stability from that of a natural shuttlecock is significant.

In view of this, in the present embodiment, for a shot whose posture is largely out of balance (a hairpin shot), the aerodynamic characteristics are improved. Note that, in the following description, a posture close to normal flight (flight with the base 2 facing the traveling direction) is referred to as "low angle of attack", and a state in which the posture is largely out of balance with respect to the traveling direction is referred to as "high angle of attack".

Artificial shuttlecock 1 of this embodiment

Fig. 5 is a schematic view of the artificial feather 10 of the first embodiment, viewed from above. Also, fig. 6 is a schematic view of a plurality of artificial feathers 10 arranged on the artificial shuttlecock 1 of the first embodiment as viewed from above. Note that portions having the same configurations as those of the comparative example are denoted by the same reference numerals, and description thereof will be omitted. Further, the definition of the direction is the same as in the comparative example. A straight line (one-dot chain line) connecting the left end (downstream end in the rotation direction) of the feather portion 12 and the central portion of the feather shaft portion 14 is an imaginary straight line M (corresponding to a first imaginary straight line). Further, a straight line (broken line) connecting the right end (upstream end in the rotation direction) of the feather portion 12 and the central portion of the feather shaft portion 14 is a virtual straight line N (corresponding to a second virtual straight line). Note that, as in the present embodiment, in the case where the sectional shape of the feather shaft portion 14 is rectangular, the central portion of the feather shaft portion 14 is a portion located at the axial center of the feather shaft portion 14, such as the intersection of the diagonal lines. As another example, if the cross-sectional shape of the feather shaft portion 14 is an ellipse, the central portion is the intersection of the major and minor axes.

As shown in fig. 6, the artificial shuttlecock 1 of the present embodiment includes a plurality of artificial feathers 10. Similar to the artificial feather 110 of the comparative example, the artificial feather 10 is arranged in a ring shape along the circumference of the flat surface of the base 2 (not shown here).

Structure of artificial feather 10

As shown in fig. 5 and 6, the artificial feathers 10 of the artificial shuttlecock 1 of the present embodiment each have a feather portion 12 and a feather shaft portion 14. In the present embodiment, the shape of the feather portion 12 is different from that of the feather portion 120 (see fig. 3B) of the above-described comparative example.

The feather portion 12 is supported by the feather shaft portion 14 similarly to the comparative example (fig. 3A).

Similarly to the comparative example, the end portion on the right side of the feather portion 14 of the feather portion 12 overlaps the inside of the left end portion of the adjacent feather portion 12 (overlap portion S).

The feather portion 12 has an inclined portion 12a on the left side of the feather shaft portion 14. The inclined portion 12a is inclined outward (toward the front side) at an angle θ (corresponding to the inclination angle) with respect to the imaginary straight line N (second imaginary straight line). Therefore, the length of the overlapping portion S in the width direction is shorter than that of the comparative example (fig. 4). As shown in fig. 6, the right end (overlapping portion S) of each feather portion 12 is not in contact with the left end (inclined portion 12a) of the adjacent feather portion 12.

Further, since the inclined portion 12a is provided in the present embodiment, the virtual straight line M (first virtual straight line) is outward (on the front side) with respect to the virtual straight line N on the left side (downstream side in the rotational direction) of the feather shaft portion 14.

With such a shape, the artificial shuttlecock 1 of the present embodiment has a larger projected area at a high angle of attack than the artificial shuttlecock 100 of the comparative example. Note that the projected area is the area of a "shadow" generated when a three-dimensional object is projected in two dimensions (here, the area when the shuttlecock is viewed from the side). As a result, as will be described later, the artificial shuttlecock 1 has a high air resistance (resistance) at a high angle of attack, and therefore, when the posture is out of balance, unstable behaviors (shaking and the like) can be suppressed, making the posture more easily stable, as compared with the comparative example (artificial shuttlecock 100).

Evaluation of characteristics of Artificial shuttlecock 1

In the basic aerodynamic characteristics of the artificial shuttlecock 1 of the present embodiment, the resistance and pitching moment were evaluated.

Among the components of force acting on the shuttlecock in the air current, the resistance is a component (component) parallel to the direction of the air current. Note that the component (component) perpendicular to the direction of the airflow is referred to as lift.

The pitching moment is the force that attempts to return to the original posture (to a low angle of attack) when there is a difference between the direction of the airflow and the orientation of the base (i.e. when the shuttlecock is tilted with respect to the airflow). The larger the pitching moment, the faster the movement in the direction of the recovered posture.

In the present embodiment, the resistance and the pitching moment are measured by using a plurality of (here, 5) samples (artificial feathers 1) having different bending angles θ (corresponding to the tilt angles) of the inclined portion 12a of the feather portion 12. Note that the sample having a bending angle of 0 degrees corresponds to the artificial shuttlecock 100 of the comparative example.

Fig. 7 is a graph showing the evaluation result of the resistance of the artificial shuttlecock 1. In the figure, the horizontal axis represents the bending angle (inclination angle), and the vertical axis represents the ratio of the relative resistance in the case where the resistance when the bending angle is 0 degrees is regarded as 100. In the evaluation, a general wind tunnel test was performed. Specifically, the artificial shuttlecock 1 is placed in the air flow of the wind tunnel device, and the resistance acting on the artificial shuttlecock 1 is measured by a load cell. Also, in fig. 7, the measured values of the angle of attack of 0 to 140 degrees are compared at measurement intervals of 10 degrees.

As shown, samples with large bend angles θ also have high resistance. This is because when the bending angle θ is large, the projected area at a high attack angle is large, which increases air resistance (drag).

Fig. 8 is a graph showing the evaluation result of the pitching moment of the artificial shuttlecock 1. In the figure, the horizontal axis represents the bending angle (tilt angle), and the vertical axis represents the ratio of the relative pitching moment in the case where the pitching moment when the bending angle is 0 degrees is regarded as 100. The method for evaluating the pitching moment is the same as in the case of the above-described resistance.

In fig. 8, although there is almost no difference between the two samples where the bending angle θ is small, it can be said that when the bending angle θ is large, the pitching moment also rises due to the increase in the resistance. These results are used to calculate a bending angle (inflection point) that exhibits a pitching effect of the pitching moment. In the present embodiment, a calculation is performed to find the intersection of a straight line passing through two points where there is little difference in pitching moment (small bending angle θ) and a straight line passing through two points where the effect is achieved (large bending angle). As a result, the bending angle exhibiting the effect was 9.6 degrees. Note that the method of calculating the inflection point is not limited thereto. For example, it is also acceptable to increase the number of samples (set the number of bending angles θ) for a small bending angle θ and a large bending angle θ, and obtain an intersection (inflection point) by using the least square method or the like.

Effect confirmation

The above five samples having different bending angles θ were used to confirm the effect. This effect was demonstrated by comparing the hair-pin net shots of three experienced badminton players. Specifically, all five samples were evaluated and scored by the paired comparison method. Note that the pair-wise comparison method is a method in which two samples (one pair) are extracted, giving a score of 1 for good samples, giving a score of 0 in the case of equivalence, and giving a score of-1 for bad samples. All pairs were evaluated by looping and statistically processed.

Fig. 9 is a diagram showing the evaluation results of the effect confirmation test. In the figure, the horizontal axis represents the bending angle θ, and the vertical axis represents the evaluation score.

As shown in the figure, a result of approximating the pitching moment is obtained. In other words, there is little difference between two samples having a small bending angle θ, but the evaluation score increases as the bending angle θ increases.

Here, similarly to the case of the above-described pitching moment, a bending angle (inflection point) exhibiting an effect is calculated. Specifically, calculation is performed to find the intersection of a straight line passing through two points having a small bending angle and a straight line passing through two points having a large bending angle. As a result, the bending angle (inflection point) exhibiting the effect was 12.2 degrees.

Based on the above results, it was confirmed that the artificial shuttlecock 1 of the present embodiment can have higher resistance and pitching moment than the artificial shuttlecock 100 of the comparative example (bending angle of 0 degree) because the bending angle θ of the inclined portion 12a is increased to some extent. Therefore, the artificial shuttlecock 1 of the present embodiment can suppress unstable behavior when the posture is out of balance, as compared with the comparative example (sample with a bending angle of 0 degrees), and can further stabilize the posture.

Note that although the feather portion 12 is provided with the overlapping portion S in the present embodiment, the overlapping portion S may be omitted. In other words, the adjacent feather portions 12 need not overlap each other in the width direction (the same applies to the following embodiments).

First modification

Fig. 10A is a schematic view of the artificial feather 10A of the first modification viewed from above. Also, fig. 10B is a schematic view of a plurality of artificial feathers 10a arranged on the artificial shuttlecock 1 as viewed from above.

In the artificial feather 10a of the first modification, at a position on the left side (downstream side in the rotational direction) of the feather shaft portion 14, the feather portion 12 is inclined (bent) outward by an angle θ with respect to the imaginary straight line N. In other words, on the left side to the feather shaft portion 14, the feather portion 12 has a tilted portion (tilted portion 12a) and a non-tilted portion (portion between the tilted portion 12a and the feather shaft portion 14).

Note that, in the case of the first modification, on the left side (the downstream side in the rotational direction) of the feather shaft portion 14, the imaginary straight line M is outward with respect to the imaginary straight line N.

Therefore, even in the artificial shuttlecock 1 of modification 1, the projected area is larger than that of the comparative example (artificial shuttlecock 100). Therefore, the posture can be more easily stabilized than in the case of the comparative example. Note that, as shown in the figure, it is desirable that the length L1 of the inclined portion 12a is longer than the length L2 of the non-inclined portion (in other words, the length L1 of the inclined portion 12a is longer than half the length from the left end (downstream end in the rotational direction) of the feather portion 12 to the feather shaft portion 14) when the feather portion 12 is viewed from above (in extension in the axial direction). According to this configuration, the projected area is larger and the posture can be more stable (aerodynamic characteristics can be improved) than the opposite case (when L2 is longer than L1).

Note that the right end portion (overlapping portion S) of the feather portion 12 may be in contact with the adjacent feather portion 12. For example, feather portion 12 may be sized to contact an adjacent feather portion 12. If adjacent feathers 12 contact each other in this manner, rotation about the central axis is more easily inhibited during normal flight (at low angles of attack). On the other hand, the bending angle θ can be increased without contacting the neighboring feather portion 12, and therefore the projected area can be increased.

Moreover, in the above-described embodiment, the bending angle θ (inclination angle) of the inclined portion 12a is constant regardless of the position in the vertical direction (axial direction). The present invention is not limited thereto, and the bending angle θ (inclination angle) may be different depending on the position in the vertical direction (axial direction). In particular, it is effective for improving aerodynamic characteristics that the bending angle θ of the inclined portion 12a increases toward the upper side (tip side) in the vertical direction. Also, in this case, since the bending angle θ is small on the side close to the base 2, the airflow entering the skirt 4 is less likely to escape outward.

Second variant

Fig. 11 is a schematic view of an artificial feather 10b of a second modification viewed from above.

As shown in the drawing, in the artificial feather 10b of the second modification, the portion of the feather portion 12 on the right side (upstream side in the rotational direction) of the feather shaft portion 14 is not flat, but curved in the front-rear direction. In the case of the second modification, the inclined portion 12a is inclined outward with respect to the imaginary straight line N, and the imaginary straight line M is located outside the imaginary straight line N on the left side (downstream side in the rotational direction) of the feather shaft portion 14.

As a result, similarly to the above-described embodiment, the projected area is large, and the posture can be stabilized (the aerodynamic characteristics can be improved).

Third modification

Fig. 12 is a schematic view of an artificial feather 10c of a third modification viewed from above.

As shown in the drawing, in the artificial feather 10c of the third modification, the right end portion of the feather portion 12 is curved inward (toward the back side). In the case of the third modification, the inclined portion 12a is inclined outward with respect to the imaginary straight line N, and the imaginary straight line M is located outside the imaginary straight line N on the left side (downstream side in the rotational direction) of the feather shaft portion 14.

As a result, similarly to the above-described embodiment, the projected area is large, and the posture can be stabilized (the aerodynamic characteristics can be improved).

Fourth modification

Fig. 13 is a schematic view of an artificial feather 10d of a fourth modification viewed from above.

As shown in the drawing, in the artificial feather 10d of the fourth modification, the feather portion 12 is bent outward on the right side (upstream side in the rotational direction) of the feather shaft portion 14. In the case of the fourth modification, the inclined portion 12a is inclined outward with respect to the imaginary straight line N, and the imaginary straight line M is located outside the imaginary straight line N on the left side (downstream side in the rotational direction) of the feather shaft portion 14.

As a result, similarly to the above-described embodiment, the projected area is large, and the posture can be stabilized (the aerodynamic characteristics can be improved).

Second embodiment

Fig. 14 is a schematic view of the artificial feather 10' of the artificial shuttlecock 1 of the second embodiment as viewed from above. The arrangement on the base 2 (not shown here) is the same as that of the first embodiment described above and will therefore not be described.

The artificial feather 10 'of the second embodiment comprises a feather portion 12' and a feather shaft portion 14.

The feather portion 12' has a basal portion 12b and a protruding portion 12 c. The base portion 12b is the same member as the feather portion 120 (fig. 3 and 4) of the comparative example, and is supported by the feather shaft portion 14. The right end portion (overlapping portion S) of the base portion 12b overlaps the inside of the adjacent feather portion 12' (base portion 12 b).

The protruding portion 12c is provided to protrude outward from the outer surface of the base portion 12 b. Further, the protruding portion 12c is provided at a position overlapping with the feather shaft portion 14 in the width direction (rotation direction).

As described above, the feather portion 12' of the second embodiment is provided with the protruding portion 12c on the outer side of the basal portion 12 b. As a result, in the second embodiment, the projected area at a high angle of attack is also large, and therefore, unstable behavior when the posture is largely out of balance can be suppressed, and the posture can be made more stable.

Note that the protruding portion 12c is not limited to being formed at the above-described position. It is sufficient that the projection 12c is formed at a position between the left end (downstream end in the rotational direction) of the feather portion 12' and the feather shaft portion 14. In other words, the projection 12c may be provided on the left side (downstream side in the rotational direction) of the feather shaft portion 14. Note that if the protruding portion 12c is provided at a position overlapping the feather portion 14 in the width direction (rotation direction) as in the present embodiment, the balance is improved, and the feather portion 12' can be easily supported by the feather portion 14.

Others

The foregoing examples are helpful in understanding the present disclosure and are not to be construed as limiting the present disclosure in any way. The present disclosure may be changed or modified in various ways without departing from the gist thereof, and includes equivalents thereof.

Description of the reference numerals

1 Artificial badminton

2 base part

3 rope-shaped member

4 skirt part

10. 10a, 10b, 10c, 10d, 10' artificial feather

12, 12' feather portion

12A inclined part

12B base part

12C projection

14 feather shaft part

14a feather support

14b root of feather

100 Artificial badminton (comparative example)

110 Artificial feather (comparative example)

120 feather part (comparative example)

S overlap

M imaginary straight line (first imaginary straight line)

N imaginary straight line (second imaginary straight line)