JP7170687B2 - racket frame and racket - Google Patents

Description

The present invention relates to a racquet frame and a racquet.

Spin performance and repulsion performance are used as evaluation indexes of racket frame and racket performance. Japanese Patent Application Laid-Open No. 2017-121431 discloses a tennis racket frame having good resilience performance and spin performance.

Conventionally, when the face is viewed from above, a part of the face is designed as a first area in which the spin performance is relatively enhanced, and the other part of the face is designed as a first area in which the repulsion performance is relatively high. A racquet frame is known which is designed as a second region which is raised to . The first region is designed so that the string can easily move in the direction along the ball-striking surface when the ball is hit. The second region is designed so that the string is less likely to move in the direction along the ball-striking surface when the ball is hit, compared to the first region.

JP 2017-121431 A

A main object of the present invention is to provide a racket frame and a racket in which spin performance in a partial area of the face portion is further improved as compared with conventional racket frames and rackets.

A racket frame according to the present invention includes a face portion and a grip portion arranged side by side in a first direction A. As shown in FIG. The face portion has a first portion having a first end located on the opposite side of the grip portion in the first direction A, and a second end located on the side of the grip portion in the first direction A. It includes one portion and a spaced-apart second portion. The first portion is formed with a plurality of first through holes that extend along the first direction A and are spaced apart from each other in a second direction B perpendicular to the first direction A. The plurality of first through-holes has a first hole closest to the center of the first portion in the second direction B and a second hole located on the side opposite to the center with respect to the first hole. In a third direction C intersecting the first direction A and the second direction B, the width of the first hole is wider than the width of the second hole.

According to the present invention, it is possible to provide a racket frame and a racket in which the spin performance of a partial region of the face portion is further improved compared to the conventional racket frame and racket.

FIG. 4 is a plan view showing the racket frame according to the embodiment; 2 is a side view of the string protector fixed to the first end of the face portion of the racket frame shown in FIG. 1, viewed from the grip portion side or the second end side; FIG. 3 is a perspective view of the string protector shown in FIG. 2; FIG. FIG. 4 is a perspective view of the string protector shown in FIG. 2 as seen from a viewpoint different from that in FIG. 3 ; 1 is a plan view showing a racket according to this embodiment; FIG. FIG. 6 is a diagram for explaining the relationship between the racket frame and strings in the racket shown in FIG. 5; 6 is a side view of the string protector fixed to the first end of the face portion of the racket shown in FIG. 5, viewed from the grip portion side; FIG. 4 is a graph comparing the spin performances of Sample 1 and Sample 2; 4 is a graph comparing the spin performance of Sample 2 and Sample 3. FIG. 4 is a photograph showing an experimental system for measuring strain amounts generated in each of the third main string portion and the fourth main string portion of the example. In the experimental system shown in FIG. 10, the third main string section and the fourth main string section were measured from the start to the end of pressurization on each of the third main string section and the fourth main string section. 4 is a graph showing the amount of distortion that occurs in each part;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

<Structure of racket frame>
As shown in FIG. 1, a racket frame 100 according to this embodiment has a face portion 1, a shaft portion 2, and a grip portion 3. As shown in FIG. The face portion 1, the shaft portion 2, and the grip portion 3 are arranged side by side in the first direction A. As shown in FIG. The shaft portion 2 is arranged between the face portion 1 and the grip portion 3 in the first direction A. As shown in FIG.

The material used for the racket frame is, for example, CFRP (Carbon Fiber Reinforced Plastic). However, the material used for the racket frame is not limited to this. For example, GFRP (Glass Fiber Reinforced Plastic) or the like can be used.

The face portion 1 has an elliptical ring shape in plan view. The longitudinal direction of the face portion 1 in plan view is along the first direction A. As shown in FIG. The lateral direction in plan view is along the second direction B orthogonal to the first direction A. As shown in FIG. A third direction C orthogonal to the first direction A and the second direction B is the hitting direction of the racket 110 .

The face portion 1 has, in the first direction A, a first end portion 1a and a second end portion 1b. The first end portion 1a is an end portion of the face portion 1 located on the opposite side of the grip portion 3 in the first direction A. As shown in FIG. The second end portion 1b is an end portion located on the grip portion 3 side in the first direction A. As shown in FIG.

The face portion 1 includes a first portion 11 having a first end 1a and a second portion 12 having a second end 1b. The first portion 11 extends along the second direction B around the first end 1a. The second portion 12 extends along the second direction B around the second end 1b. The second portion 12 is spaced apart from the first portion 11 in the first direction A. As shown in FIG.

Face portion 1 further includes a third portion 13 and a fourth portion 14 . The third portion 13 is arranged between the first portion 11 and the second portion 12 and connects one end of the first portion 11 and one end of the second portion 12 . The fourth portion 14 is arranged between the first portion 11 and the second portion 12 and connects the other end of the first portion 11 and the other end of the second portion 12 . The fourth portion 14 is spaced apart from the third portion 13 in the second direction B. As shown in FIG.

Each of the first portion 11, the second portion 12, the third portion 13 and the fourth portion 14 of the face portion 1 has an inner periphery 1c and an outer periphery 1d. The face portion 1 is formed with a plurality of through holes for passing strings. A plurality of through holes are opened in each of the inner periphery 1c and the outer periphery 1d. The plurality of through-holes includes a plurality of first through-holes 21, a plurality of second through-holes 24, a plurality of third through-holes 25, and a plurality of fourth through-holes 26 shown below.

A plurality of first through holes 21 are formed in the first portion 11 . Each of the plurality of first through holes 21 extends along the first direction A and is spaced apart from each other in the second direction B. As shown in FIG. A detailed configuration of the plurality of first through holes 21 will be described later.

A plurality of second through holes 24 are formed in the second portion 12 . Each of the plurality of second through holes 24 is spaced apart from each other in the second direction B. As shown in FIG. The interval between two second through holes 24 adjacent in the second direction B gradually widens, for example, as the distance from the center line CL passing through the first end 1a and the second end 1b increases.

A plurality of third through holes 25 are formed in the third portion 13 . Each of the plurality of third through-holes 25 is spaced apart from each other in the first direction A. As shown in FIG.

A plurality of fourth through holes 26 are formed in the fourth portion 14 . Each of the plurality of fourth through-holes 26 is spaced apart from each other in the first direction A. As shown in FIG.

The shaft portion 2 has a first branch member 2A and a second branch member 2B. The grip part 3 has a grip member 3A and a grip 3B. A first branch member 2A and a second branch member 2B are branched from the grip member 3A. The grip 3B is formed to cover the grip member 3A. Polyurethane, for example, is used for the grip 3B.

Details of the plurality of first through holes 21 will be described below with reference to FIGS. 2 to 5. FIG. The plurality of first through holes 21 are holes through which the main string portions 201 of the strings 200 pass in the racket 110 .

As shown in FIGS. 2-5, the racquet frame 100 further comprises a grommet 15 attached to the first portion 11, for example. As shown in FIG. 3, the grommet 15 has a grommet body 15a and a plurality of projections 15b. Each of the plurality of protrusions 15b protrudes toward the second portion 12 in the first direction A with respect to the grommet body 15a. As shown in FIGS. 2 to 5, each of the plurality of first through holes 21 is formed in the plurality of protrusions 15b of the grommet 15. As shown in FIG. Grommet 15 protects main string portion 201 of string 200 . Preferably, grommet 15 is separate from face portion 1 . The material forming the grommet 15 is nylon resin, for example.

As shown in FIGS. 2 and 3, the first portion 11 is formed with a plurality of insertion holes 11a through which the plurality of projections 15b are inserted. Each of the plurality of insertion holes 11a may have any configuration as long as each of the plurality of projections 15b can be inserted therein. When viewed from the first direction A, the planar shape of each of the plurality of insertion holes 11a is circular, for example.

As shown in FIG. 2, each of the plurality of first through holes 21 is provided line-symmetrically with respect to a center line CL (imaginary line) passing through the first end 1a and the second end 1b. . The plurality of first through-holes 21 includes a first hole 22a, a second hole 23a, a third hole 23b, a third It includes 4 holes 22b, a fifth hole 22c and a sixth hole 23c. The first hole 22a, the second hole 23a, the third hole 23b, the fourth hole 22b, the fifth hole 22c, and the sixth hole 23c are arranged away from the center line CL of the first portion 11 in the order described above. there is Note that the center line CL passes through the central axis of the grip portion 3 .

The first hole 22 a is arranged at a position closest to the center line CL in the second direction B among the plurality of first through holes 21 .

The second hole 23a is arranged on the side opposite to the center line CL with respect to the first hole 22a. The second hole 23a is adjacent to the first hole 22a. The second hole 23 a is arranged at a position second closest to the center line CL of the first portion 11 in the second direction B among the plurality of first through holes 21 .

The third hole 23b is arranged on the side opposite to the first hole 22a with respect to the second hole 23a. The third hole 23b is adjacent to the second hole 23a. The third hole 23b is arranged at a position third closest to the center line CL of the first portion 11 in the second direction B. As shown in FIG.

The fourth hole 22b is arranged on the side opposite to the second hole 23a with respect to the third hole 23b. The fourth hole 22b is adjacent to the third hole 23b. The fourth hole 22b is arranged at a position fourth closest to the center line CL of the first portion 11 in the second direction B. As shown in FIG.

The fifth hole 22c is arranged on the side opposite to the third hole 23b with respect to the fourth hole 22b. The fifth hole 22c is adjacent to the fourth hole 22b. The fourth hole 22b is arranged at a position fifth closest to the center line CL of the first portion 11 in the second direction B. As shown in FIG.

The sixth hole 23c is arranged on the side opposite to the fourth hole 22b with respect to the fifth hole 22c. The sixth hole 23c is adjacent to the fifth hole 22c. The sixth hole 23c is arranged at a position sixth closest to the center line CL of the first portion 11 in the second direction B. As shown in FIG.

As shown in FIGS. 2 and 3, the planar shape of each of the first hole 22a and the fourth hole 22b is an elliptical shape elongated in the third direction C when viewed from the first direction A. As shown in FIGS. The longitudinal direction of each of the first hole 22a and the fourth hole 22b extends along the third direction C when viewed from the first direction A. As shown in FIG. As viewed from the first direction A, the lateral direction of each of the first hole 22a and the fourth hole 22b extends along the second direction B. As shown in FIG. When viewed from the first direction A, the planar shape of the fifth hole 22c is circular, for example.

As shown in FIGS. 2 and 3, when viewed from the first direction A, the planar shape of each of the second hole 23a, the third hole 23b, and the sixth hole 23c is circular, for example.

As shown in FIG. 2, in the third direction C, the width W1 of the first hole 22a is wider than the width W2 of the second hole 23a. In the second direction B, the width of the first hole 22a may be equal to the width of the second hole 23a, for example.

As shown in FIG. 2, in the third direction C, the width W3 of the third hole 23b is narrower than the width W4 of the fourth hole 22b. In the second direction B, the width of the third hole 23b may be equal to the width of the fourth hole 22b, for example.

As shown in FIG. 2, in the third direction C, the width W5 of the fifth hole 22c may be greater than the width W6 of the sixth hole 23c, and in the second direction B, the width of the fifth hole 22c may be , for example, may be wider than the width of the sixth hole 23c.

In the second direction B, each width of the plurality of first through holes 21 may be equal to each other, for example.

In addition, the planar shape of each of the plurality of first through holes 21 when viewed from the first direction A is not particularly limited as long as the magnitude relationship of the widths described above is realized. When viewed from the first direction A, the planar shape of the fifth hole 22c may be an elliptical shape. In this case, the longitudinal direction of the fifth hole 22c is along the third direction C when viewed from the first direction A. As shown in FIG. The short direction of the fifth hole 22c extends along the second direction B when viewed from the first direction A. As shown in FIG.

In the third direction C, the width of each of the first holes 22a, the fourth holes 22b, and the fifth holes 22c is wider than the width of each of the plurality of second through holes 24. As shown in FIG.

As shown in FIGS. 5 and 7, the width in the third direction C and the width in the second direction B of each of the plurality of first through holes 21 are equal to or greater than the outer diameter of the string 200, preferably wider than the outer diameter. The width in the third direction C and the width in the second direction B of each of the plurality of first through holes 21 are narrower than the width in the third direction C and the width in the second direction B of each of the plurality of insertion holes 11a.

As shown in FIG. 2, in the second direction, the distance L1 between two adjacent first holes 22a across the center line CL is longer than the distance L2 between the first hole 22a and the second hole 23a. short. In other words, in the second direction, the distance L1/2 between the centerline CL and the first hole 22a is shorter than half the distance L2 between the first hole 22a and the second hole 23a.

As shown in FIG. 2, in the second direction, the distance L3 between the second hole 23a and the third hole 23b is shorter than the distance L2 between the first hole 22a and the second hole 23a. In the second direction, the distance L4 between the third hole 23b and the fourth hole 22b is longer than the distance L3 between the second hole 23a and the third hole 23b. In the second direction, the distance L5 between the fourth hole 22b and the fifth hole 22c is shorter than the distance L4 between the third hole 23b and the fourth hole 22b. In the second direction, the distance L6 between the fifth hole 22c and the sixth hole 23c is longer than the distance L5 between the fourth hole 22b and the fifth hole 22c. Note that the distances L1 to L6 described above are the distances between the centers of the holes in the second direction B. As shown in FIG.

<Racquet configuration>
Next, racket 110 according to the present embodiment will be described with reference to FIGS. 5 to 7. FIG. As shown in FIGS. 5 to 7, the racket 110 includes a racket frame 100 and strings 200 strung on the face portion 1 of the racket frame 100. FIG.

As shown in FIG. 6, the string 200 is passed through each of the plurality of first through holes 21, the plurality of second through holes 24, the plurality of third through holes 25, and the plurality of fourth through holes 26. there is The string 200 has a plurality of main string portions 201 , a plurality of folded portions 202 , a plurality of folded portions 203 and a plurality of cross string portions 204 .

The multiple main string portions 201 extend along the first direction A between the multiple first through holes 21 and the multiple second through holes 24 . The multiple cross string portions 204 extend along the second direction B between the multiple third through holes 25 and the multiple fourth through holes 26 .

The plurality of folded portions 202 are arranged outside the plurality of first through holes 21 . The plurality of folded portions 202 includes a first folded portion 202a arranged between the first hole 22a and the second hole 23a, and a second folded portion 202a arranged between the third hole 23b and the fourth hole 22b. It has a folded portion 202b and a third folded portion 202c arranged between the fifth hole 22c and the sixth hole 23c.

In other words, the string 200 is folded back outside the first hole 22a and the second hole 23a between the first hole 22a and the second hole 23a. The main string portion 201 extending along the first direction A from the first hole 22a and the main string portion 201 extending along the first direction A from the second hole 23a are connected via the first folded portion 202a. there is

The string 200 is folded back outside the third hole 23b and the fourth hole 22b between the third hole 23b and the fourth hole 22b. The main string portion 201 extending along the first direction A from the third hole 23b and the main string portion 201 extending along the first direction A from the fourth hole 22b are connected via the second folded portion 202b. there is

The string 200 is folded back outside the fifth hole 22c and the sixth hole 23c between the fifth hole 22c and the sixth hole 23c. The main string portion 201 extending along the first direction A from the fifth hole 22c and the main string portion 201 extending along the first direction A from the sixth hole 23c are connected via the third folded portion 202c. there is

As shown in FIGS. 6 and 7 , the plurality of folded portions 203 are arranged outside the plurality of second through holes 24 . The plurality of folded portions 203 are arranged between the fourth folded portion 203a arranged between the first folded portion 202a and the second folded portion 202b and between the second folded portion 202b and the third folded portion 202c. and a fifth folded portion 203b.

The main string portion 201 extending along the first direction A from the second hole 23a and the main string portion 201 extending along the first direction A from the third hole 23b are connected via a fourth folded portion 203a. there is The main string portion 201 extending along the first direction A from the fourth hole 22b and the main string portion 201 extending along the first direction A from the fifth hole 22c are connected via a fifth folded portion 203b. there is

The string 200 is passed through two of the plurality of second through holes 24 between the second hole 23a and the third hole 23b. The string 200 includes two second through-holes 24 arranged between the second hole 23a and the third hole 23b at positions close to the center line CL in the second direction B among the plurality of second through-holes 24. 24 (the second through hole of the first group) and has the fourth folded portion 203a.

The string 200 is passed through two of the plurality of second through holes 24 between the fourth hole 22b and the fifth hole 22c. The string 200 is arranged between the fourth hole 22b and the fifth hole 22c at a position farther from the center line CL than the second through holes of the first group among the plurality of second through holes 24. It is passed through the two second through holes 24 (the second group of second through holes) and has the fifth folded portion 203b.

In the fifth hole 22c a knot is arranged, for example two strings connected in series by knotting each other.

As shown in FIG. 7, in the second direction B, a distance L12 between the main string portion 201 passed through the first hole 22a and the main string portion 201 passed through the second hole 23a is It is longer than the distance L11 between the main string portions 201 passed through the first holes 22a.

In the second direction B, a distance L12 between the main string portion 201 passed through the first hole 22a and the main string portion 201 passed through the second hole 23a is passed through the second hole 23a. It is longer than the distance L13 between the main string portion 201 and the main string portion 201 passed through the third hole 23b.

In the second direction B, a distance L13 between the main string portion 201 passed through the second hole 23a and the main string portion 201 passed through the third hole 23b is passed through the third hole 23b. It is shorter than the distance L14 between the main string portion 201 and the main string portion 201 passed through the fourth hole 22b.

In the second direction B, a distance L14 between the main string portion 201 passed through the third hole 23b and the main string portion 201 passed through the fourth hole 22b is passed through the fourth hole 22b. It is longer than the distance L15 between the main string portion 201 and the main string portion 201 passed through the fifth hole 22c.

In the second direction B, a distance L15 between the main string portion 201 passed through the fourth hole 22b and the main string portion 201 passed through the fifth hole 22c is passed through the fifth hole 22c. It is shorter than the distance L16 between the main string portion 201 and the main string portion 201 passed through the sixth hole 23c.

As shown in FIG. 5, the face portion 1 of the racket 110 includes a first region R1 positioned closer to the first portion 11 than the center of the face portion 1 in the second direction B, and a face portion R1 in the second direction B. A second region R2 including the center of 1 is formed. The first region R1 is closer to the first portion 11 than the second region R2. Therefore, the spin performance and rebound performance when hitting a ball in the first region R1 are more susceptible to the configuration of the plurality of first through holes 21 than the spin performance and rebound performance when hitting a ball in the second region R2. .

The method of stringing the strings 200 on the face portion 1 of the racket frame 100 is not particularly limited. An example of how to stretch the main string portion 201 will be described below.

The string 200 is first passed through the hole closest to the center line CL among the plurality of second through holes 24 from the outside toward the inside as indicated by the arrow in FIG. 6, for example. Next, the string 200 is passed through the first hole 22a (see FIGS. 2 and 7) from the inside toward the outside, and then folded back at the outside (first folded portion 202a) to form the second hole 23a. (see FIGS. 2 and 7) are passed from the outside to the inside.

Next, the string 200 is passed from the inner side to the outer side through the second through-hole 24 that is the second closest to the center line CL, and then folded back at the outer side (fourth folded portion 203a). , the hole closest to the center line CL among the plurality of second through holes 24 from the outside toward the inside. Next, the string 200 is passed through the third hole 23b (see FIGS. 2 and 7) from the inside toward the outside, and then folded back at the outside (the second folded portion 202b) to form the fourth hole 22b (see FIG. 2 and FIG. 7). 2 and 7) is passed from the outside to the inside.

Next, the string 200 is passed from the inner side to the outer side through the hole that is the fourth closest to the center line CL among the plurality of second through holes 24, and then folded back at the outer side (fifth folded portion 203b). , through the hole closest to the center line CL among the plurality of second through holes 24 from the outside toward the inside. Next, after the string 200 is passed through the fifth hole 22c (see FIGS. 2 and 7) from the inside toward the outside, it is folded back on the outside (the third folded portion 202c) to the sixth hole 23c (see FIG. 2 and FIG. 7). 2 and 7) is passed from the outside to the inside.

Next, the string 200 is passed from the inside to the outside through the hole closest to the center line CL among the plurality of second through holes 24 . In this way, the string 200 has a plurality of first through-holes such that the first folded portion 202a, the fourth folded portion 203a, the second folded portion 202b, the fifth folded portion 203b, and the third folded portion 202c are formed in this order. A plurality of main string portions 201 can be formed by passing through the holes 21 and the plurality of second through holes 24 .

Note that the string 200 may be stretched in the first direction A by reversing the stretching method described above. The prepared string 200 is first passed through the first hole 22a from the outside to the inside, and then passed through the hole closest to the center line CL among the plurality of second through holes 24 from the inside to the outside. good too.

Next, examples of racket frame 100 and racket 110 according to the present embodiment will be described.

<Example 1>
In this example, the spin performance of the racket frames according to Samples 1 to 3, in which the configurations of the plurality of first through holes are different from each other, was evaluated.

(Samples 1-3)
In the racket frame according to Sample 1, as a comparative example, the plurality of first through holes have equal intervals in the second direction B and the plurality of first through holes have equal widths in the third direction C. and

In the racket frame according to Sample 2, the intervals in the second direction B of each of the plurality of first through holes are equal to each other, but the distance between two adjacent first holes sandwiching the center line CL in the second direction B is , is shorter than the distance between the first hole and the second hole.

A racket frame 100 was used as the sample 3 . That is, the sample 1 differs from the sample 3 only in that the plurality of first through-holes have the same interval in the second direction B and the plurality of first through-holes have the same width in the third direction C. made different. Sample 2 was different from Sample 3 only in that the intervals in the second direction B of the plurality of first through holes were equal to each other. Sample 2 differs from Sample 1 only in that the distance between two first holes adjacent to each other across the center line CL in the second direction B is shorter than the distance between the first and second holes. I assumed.

In Sample 3, the distance between the main string portion passed through the first hole and the main string portion passed through the second hole in the second direction B was the main string portion passed through the second hole. and the distance between the main string portion passed through the third hole.

(Evaluation method)
A tennis ball fired from a tennis ball launcher was caused to collide with the first region of the racket whose grip portion was fixed to the jig, and the number of spins of the tennis ball rebounded by the collision was measured. A tennis ball launcher launched a tennis ball into the racket such that the center of the tennis ball overlapped the centerline. The direction in which the tennis ball launcher shoots tennis balls is perpendicular to the center line of the racket, and the angle of inclination of the shooting direction with respect to the second direction of the racket is 15 degrees or 30 degrees. , was set. A hard tennis ball was used as the tennis ball. A high-speed camera was used to measure the spin rotation speed.

(Evaluation results)
FIG. 8 is a graph comparing the evaluation results of sample 1 and sample 2. In FIG. FIG. 9 is a graph comparing the evaluation results of sample 2 and sample 3. In FIG.

As shown in FIG. 8, the spin rotation number of the tennis ball rebounded from sample 2 was higher than the spin rotation number of the tennis ball rebounded from sample 1, regardless of the tilt angle. When the ball was hit with the inclination angle of 15 degrees, the spin rate of the tennis ball rebounding from Sample 2 was 17% higher than the spin rate of the tennis ball rebounding from Sample 1. When the ball was hit with the inclination angle of 30 degrees, the spin rate of the tennis ball rebounding from Sample 2 was 6% higher than the spin rate of the tennis ball rebounding from Sample 1.

In general, when the ball is hit with the inclination angle of 30 degrees, the ball is more likely to spin than when the ball is hit with the inclination angle of 15 degrees. In other words, it was confirmed that the spin performance of Sample 2 was higher than that of Sample 1 even under the hitting condition of the inclination angle of 30 degrees, where even Sample 1 was susceptible to spin.

As shown in FIG. 9, the spin rotation number of the tennis ball rebounding from Sample 3 was higher than the spin rotation number of the tennis ball rebounding from Sample 2 even under the above-described hitting condition of the inclination angle of 30 degrees, which tends to cause spin. There were many When the ball was hit with the inclination angle of 30 degrees, the spin rate of the tennis ball rebounding from sample 3 was 7% higher than the spin rate of the tennis ball rebounding from sample 2.

In other words, it was confirmed that the spin performance of sample 3 was higher than that of sample 2 even under the hitting condition of the inclination angle of 30 degrees where spin was likely to occur. Furthermore, it was confirmed from these results that the spin performance of Sample 3 was higher than that of Sample 1.

<Example 2>
In this example, the distortion characteristics of the first region of the racket according to sample 3 were evaluated.

(Evaluation method)
First, a strain sensor was attached to each of the two main string portions 201 extending along the first direction A from each of the third hole 23b and the fourth hole 22b (see FIGS. 2 and 7) of the sample 3. The mounting position of the strain sensor in each main string portion 201 is between each of the third hole 23b and the fourth hole 22b and the portion that intersects with the cross string portion 204 closest to the first end portion 1a in the second direction B. did. It should be noted that each main string portion 201 is composed of one string, as described above, and is folded back by the second folding portion 202b.

Next, as shown in FIG. 10, an indenter having a hemispherical shape and an outer diameter equal to the outer diameter of a tennis ball is applied in the third direction C to the first region of the sample 3 fixed in the third direction C. It was pressed, and the change in each strain amount from the start of pressing to the end of pressing was evaluated. The indenter was arranged so that the top of the indenter overlapped in the third direction C with the middle point in the second direction B of the two main string portions 201 in the first region. That is, each of the two main string portions 201 was pressed under the same conditions by the indenter.

FIG. 11 is a graph showing the evaluation results. The horizontal axis of FIG. 11 indicates the time (unit: ms) from the start of pressing to the end of pressing, and the horizontal axis of FIG. 11 indicates the amount of strain. A line segment D in FIG. 11 indicates the strain amount of the main string portion 201 extending along the first direction A from the third hole 23b, and a line segment E in FIG. shows the strain amount of the main string portion 201 extending along the .

As shown in FIG. 11, it was confirmed that there was a time difference Δt between the main string portion 201 extending from the fourth hole 22b and the main string portion 201 extending from the third hole 23b until distortion started. A width W4 in the third direction C of the fourth hole 22b is wider than a width W3 in the third direction C of the third hole 23b. Therefore, the main string portion 201 extending from the fourth hole 22b moves more easily in the third direction C than the main string portion 201 extending from the third hole 23b. Since each of the two main string portions 201 begins to be distorted after moving in the third direction C, the time difference Δt is determined by the difference in ease of movement in the third direction C between the two main string portions 201 . presumably due to its existence.

Furthermore, as shown in FIG. 11, a maximum strain amount difference ΔST was confirmed between the main string portion 201 extending from the fourth hole 22b and the main string portion 201 extending from the third hole 23b. Furthermore, the strain amount of the main string portions 201 extending from the fourth holes 22b was always smaller than the strain amount of the main string portions 201 extending from the third holes 23b until the strain amount of each main string portion 201 reached its maximum. . Movement of each main string portion 201 in the third direction C is realized by a portion of the force applied to each main string portion 201, and distortion of each main string portion 201 is achieved by the remainder of the force applied to each main string portion 201. Realized. Therefore, the strain amount difference after a predetermined period of time and the maximum strain amount difference ΔST also differ in the easiness of movement in the third direction C between the two main string portions 201 . presumably caused by this.

Since the time difference Δt is formed between the two main string portions 201 connected via the second folded portion 202b, the two main string portions 201 are pressed in the third direction C, and the time difference Δt is It is easy to move in the first direction A until the time elapses. Furthermore, the strain amount difference after a predetermined time and the maximum strain amount difference ΔST are formed between the two main string portions 201 connected via the second folded portion 202b, thereby forming two main strings. The portion 201 tends to move in the first direction A during the time from when it is pressed in the third direction C until it is no longer pressed.

As a result, for example, the main string portion 201 extending from the fourth hole 22b is pulled toward the main string portion 201 extending from the third hole 23b, and tends to move in the first direction A toward the first portion 11 side. When the two main string portions 201 move as described above, a tennis ball that collides with the two main string portions 201 in the first region is likely to be spinned. This action is not only between the two main string portions 201 extending from each of the third hole 23b and the fourth hole 22b, but also between the two main string portions 201 extending from each of the first hole 22a and the second hole 23a, and It is also realized between the two main string portions 201 extending from each of the fifth hole 22c and the sixth hole 23c.

The present inventors believe that the evaluation results shown in FIG. 9 of the first embodiment were obtained for the above reasons considered from the evaluation results of the second embodiment.

<Effect>
Next, the effects of the racket frame and the racket according to the present embodiment will be described based on the first and second examples.

The racket frame 100 includes a face portion 1 and a grip portion 3 arranged side by side in the first direction A. As shown in FIG. The face portion 1 includes a first portion 11 having a first end portion 1a located on the side opposite to the grip portion 3 in the first direction A, and a second end portion 1b located on the side of the grip portion 3 in the first direction A. and includes a first portion 11 and a spaced-apart second portion. The first portion 11 has a plurality of first through holes 21 extending along the first direction A and spaced apart from each other in a second direction B perpendicular to the first direction A. As shown in FIG. The plurality of first through holes 21 includes a first hole 22a closest to the center of the first portion 11 in the second direction B and a second hole 23a located on the opposite side of the first hole 22a from the center. have. In a third direction C intersecting the first direction A and the second direction B, the width of the first hole 22a is wider than the width of the second hole 23a.

As described in Example 1 above, the present inventors found that in the racket frame 100 having the above configuration (Sample 3 of Examples 1 and 2 described above), the interval in the second direction B between the first through-holes and the When the widths in the three directions C are equal to each other (Sample 1 in Example 1 described above), and the intervals in the second direction B of the first through holes are different from each other, but the widths in the third direction C of the first through holes are It was found that the spin performance was improved by 7% compared to the case of being equal to each other (Sample 2 in Example 1 described above).

In the racket frame 100, the distance L1/2 between the center line CL and the first hole 22a in the second direction B is shorter than half the distance L2 between the first hole 22a and the second hole 23a. That is, the distance L1 is shorter than the distance L2.

As described in Example 1 above, the inventors found that the distance L1/2 between the center line CL and the first hole 22a in the second direction B is the distance between the first hole 22a and the second hole 23a. When shorter than half the distance L2 (Sample 2 in Example 1 described above), the distance L1/2 between the center line CL and the first hole 22a in the second direction B is the distance between the first hole 22a and the second hole. It was found that the spin performance was improved by 6% compared to the case where the distance L2 between 23a was equal to half (Sample 1 in Example 1 described above).

Regarding this, the longer the distance between the two main string portions 201 adjacent to each other in the second direction B in the first region R1, the more the two main string portions 201 and the tennis ball interact when the ball is hit in the first region R1. are likely to differ, and a difference in force applied to the two main string portions 201 at the time of hitting a ball is likely to occur. The longer the distance in the second direction B between the two main string portions 201 connected via the folded portion 202, the greater the difference in force between the two main string portions 201. The string part 201 becomes easier to move to one side in the first direction A. As shown in FIG. As a result, the tennis ball that collides with the two main string portions 201 is likely to be spinned. That is, the longer the distance L2, the more likely it is that the tennis ball that collides with the main string portion 201 passed through the first hole 22a and the main string portion 201 passed through the second hole 23a will be spinned.

On the other hand, the main string portion 201 passed through each first hole 22a is not connected via the folded portion 202, and even if the distance L1 is increased, the main string portion 201 passed through each first hole 22a is not connected. does not tend to move in the first direction A. If the distance L1 is shorter than the distance L2, the distance L2 can be lengthened accordingly. That is, if the distance L1 is shorter than the distance L2, the spin performance of the racket frame 100 is efficiently enhanced.

In the racket frame 100 described above, the plurality of first through holes 21 are the third hole 23b located on the side opposite to the first hole 22a with respect to the second hole 23a, and the first hole 22a with respect to the third hole 23b. and a fourth hole 22b located on the opposite side. In the third direction C, the width W4 of the fourth hole 22b is wider than the width W3 of the third hole 23b.

In such a racket frame 100, when a ball is hit with two main string portions 201 extending from each of the first hole 22a and the second hole 23a in the first region R1, each of the third hole 23b and the fourth hole 22b A high spin performance is exhibited when hitting a ball with two main string portions 201 extending from each of the first to fourth holes 22a to 22b. Therefore, in the racket frame 100, the first width W1 is wider than the second width W2, but the fourth width W4 is equal to the third width W3, thereby exhibiting high spin performance. wide area.

In the racket frame 100, the distance L3 between the second hole 23a and the third hole 23b in the second direction B is the distance L2 between the first hole 22a and the second hole 23a, and the distance L2 between the first hole 22a and the third hole 23b. It is shorter than the distance L4 to the fourth hole 22b.

If the distance L3 is shorter than the distances L2 and L4, the spin performance of the racket frame 100 is efficiently enhanced for the same reason as when the distance L1 is shorter than the distance L2.

A racket 110 includes a racket frame 100 and a string 200 stretched over a face portion 1 and including a plurality of main string portions extending along a first direction A between a first portion 11 and a second portion 12. Prepare. The string 200 is passed through the plurality of first through holes 21, and is folded back between the first hole 22a and the second hole 23a outside the first hole 22a and the second hole 23a. 1 folded portion 202a).

By including the racket frame 100 , the racket 110 can achieve the same effects as the racket frame 100 .

In the racket 110, the distance between the main string portion passed through the first hole 22a and the main string portion passed through the second hole 23a in the second direction B is It is longer than the distance between the main string portion inserted through the third hole 23b and the main string portion passed through the third hole 23b.

The embodiments disclosed this time are illustrative in all respects and should be considered not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described embodiments, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

Reference Signs List 1 face portion 1a first end portion 1b second end portion 1c inner periphery 1d outer periphery 2 shaft portion 2A first branch member 2B second branch member 3 grip portion 3A grip member 3B Grip 11 First portion 11a Insertion hole 12 Second portion 13 Third portion 14 Fourth portion 15 Grommet 15a Grommet body 15b Projection 21 First through hole 22a First hole 22b Fourth hole 22c fifth hole 23a second hole 23b third hole 23c sixth hole 24 second through hole 25 third through hole 26 fourth through hole 100 racket frame 110 racket 200 string 201 main string portion 202, 203 folded portion 202a first folded portion 202b second folded portion 202c third folded portion 203a fourth folded portion 203b fifth folded portion 204 cross string portion.

Claims (8)

A face portion and a grip portion arranged side by side in a first direction,
The face portion has a first portion having a first end located on the side opposite to the grip portion in the first direction, and a second end located on the side of the grip portion in the first direction. and a second portion spaced apart from the first portion;
The first portion is formed with a plurality of first through holes extending along the first direction and spaced apart from each other in a second direction orthogonal to the first direction,
The plurality of first through holes includes two first holes positioned closest to a center line passing through the first end and the second end and the second direction of the two first holes. and at least two second holes located on both sides of the
In a third direction intersecting the first direction and the second direction, each width of the two first holes is wider than each width of the two second holes,
In the second direction, the distance between each of the two first holes and a center line passing through the first end and the second end is less than half the shortest distance between the racket frame. A face portion and a grip portion arranged side by side in a first direction,
The face portion has a first portion having a first end located on the side opposite to the grip portion in the first direction, and a second end located on the side of the grip portion in the first direction. and a second portion spaced apart from the first portion;
The first portion is formed with a plurality of first through holes extending along the first direction and spaced apart from each other in a second direction orthogonal to the first direction,
The plurality of first through holes includes two first holes positioned closest to a center line passing through the first end and the second end and the second direction of the two first holes. and at least two second holes located on both sides of the
In a third direction intersecting the first direction and the second direction, the width of each of the two first holes is wider than the width of each of the two second holes.
The plurality of first through holes includes two third holes located on the opposite side of the two second holes from the two first holes, and the two third holes of the two third holes. and two fourth holes located on the opposite side of the first hole,
In the third direction, the width of each of the two fourth holes is wider than the width of each of the two third holes ,
The shortest distance between the two second holes and the two third holes in the second direction is the shortest distance between the two first holes and the two second holes, and the shortest distance between the two A racket frame shorter than the shortest distance between a third hole and said two fourth holes . A face portion and a grip portion arranged side by side in a first direction,
The face portion has a first portion having a first end located on the side opposite to the grip portion in the first direction, and a second end located on the side of the grip portion in the first direction. and a second portion spaced apart from the first portion;
The first portion is formed with a plurality of first through holes extending along the first direction and spaced apart from each other in a second direction orthogonal to the first direction,
The plurality of first through holes includes two first holes positioned closest to a center line passing through the first end and the second end and the second direction of the two first holes. and at least two second holes located on both sides of the
In a third direction intersecting the first direction and the second direction, the width of each of the two first holes is wider than the width of each of the two second holes.
the second portion is formed with a plurality of second through holes extending along the first direction and spaced apart from each other in the second direction;
A racket frame , wherein a width of each of the two first holes is wider than a width of each of the plurality of second through holes in the third direction . a racket frame according to claim 1;
a string stretched over the face portion and including a plurality of main string portions extending along the first direction between the first portion and the second portion;
The string is passed through the plurality of first through holes, and between the first hole and the second hole located on one side or the other side in the second direction with respect to the center line, A racket that is folded back outside the first hole and the second hole. the second portion is formed with a plurality of second through holes extending along the first direction and spaced apart from each other in the second direction;
The racket frame according to claim 2, wherein the width of each of the two first holes is wider than the width of each of the plurality of second through holes in the third direction. a racket frame according to claim 5;
a string stretched over the face portion and including a plurality of main string portions extending along the first direction between the first portion and the second portion;
The string is passed through the plurality of first through holes, and between the first hole and the second hole located on one side or the other side in the second direction with respect to the center line, A racket that is folded back outside the first hole and the second hole. The string is arranged between the second hole and the third hole located on one side or the other side in the second direction with respect to the center line, and the two second through-holes among the plurality of second through-holes. 7. A racket according to claim 6, which is passed through two through holes. A face portion and a grip portion arranged side by side in a first direction,
The face portion has a first portion having a first end located on the side opposite to the grip portion in the first direction, and a second end located on the side of the grip portion in the first direction. and a second portion spaced apart from the first portion;
The first portion is formed with a plurality of first through holes extending along the first direction and spaced apart from each other in a second direction orthogonal to the first direction,
The plurality of first through holes includes two first holes positioned closest to a center line passing through the first end and the second end and the second direction of the two first holes. two second holes respectively located on both sides of the two second holes, two third holes located on the opposite side of the two first holes with respect to the two second holes, and the two third holes and two fourth holes located on the opposite side of the two first holes,
In a third direction intersecting the first direction and the second direction, the width of the two first holes is wider than the width of the two second holes,
a string stretched over the face portion and including a plurality of main string portions extending along the first direction between the first portion and the second portion;
The string is passed through the plurality of first through holes,
In the second direction, the shortest distance between the main string portion passed through each of the two first holes and the main string portion passed through each of the two second holes is A racket longer than the shortest distance between the main string portion passed through each of the two second holes and the main string portion passed through each of the two third holes.

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