WO2025134549A1 - Badminton racket - Google Patents

Abstract

The present invention improves productivity while achieving both weight reduction and high rigidity of a frame, and enables placement of a grommet having improved durability in a groove of the frame. An annular frame (13) of a badminton racket (10) comprises: an outer forming body (21) that forms an outer side in an outer-inner direction; and a groove (17) that is recessed inward in the outer forming body and forms an opening (17a) on the outer side. The groove includes a bottom portion (17b); a first inclined surface (17c) connecting the bottom portion and a forming edge on the front side of the opening; and a second inclined surface (17d) connecting the bottom portion and a forming edge on the back side of the opening. The first inclined surface and the second inclined surface extend in a substantially linear direction when viewed in a cross-section orthogonal to an extending direction of the frame. The width (W1) in the front-back direction of the groove is set to at least 4.1 times the width (W4) in the front-back direction of the bottom portion.

Description

Badminton Racket

The present invention relates to a badminton racket with an annular frame.

Badminton is played by a player swinging a racket to hit a shuttlecock. Patent Document 1 discloses a badminton racket with a frame formed in a loop shape. In Patent Document 1, a groove is formed on the outer surface of the frame, and a grommet with a hole for inserting a string is disposed in the groove.

Utility Model Registration No. 3223277

Here, in order to improve playing performance, badminton racket frames are required to be both lightweight and highly rigid. In addition, there is a demand for good productivity in the manufacture of frames using molding dies.

Furthermore, the grommets are required to be durable against stresses such as stringing at high tension. In other words, the shape of the grooves in the frame is required to be formed so that durable grommets can be placed in them.

The present invention was made in consideration of these points, and aims to provide a badminton racket that can be easily produced while achieving both a lightweight and highly rigid frame, and that allows for the placement of grommets with increased durability in the grooves of the frame.

The badminton racket of the present invention is a badminton racket that includes an annular frame, shaft, and grip in the longitudinal direction, and the frame includes an outer forming body that forms the outside in the outward-inward direction, an inner forming body that forms the inside in the outward-inward direction, and a groove that is recessed inward in the outer forming body and forms an opening on the outside, and the groove includes a bottom, a first inclined surface that connects the bottom and the edge of the front side of the opening, and a second inclined surface that connects the bottom and the edge of the back side of the opening, and the first inclined surface and the second inclined surface extend in a substantially straight direction when viewed in cross section on a plane perpendicular to the extension direction of the frame, and the width of the groove in the front-back direction is set to be 4.1 times or more the width of the bottom in the front-back direction.

In accordance with the present invention, the bottom becomes relatively small, so that each inclined surface becomes relatively large, and the groove can be formed into an approximately V-shape in cross section by each inclined surface. This improves the rigidity of the frame, and the weight can be reduced by reducing the base material of the frame to the extent that such improved rigidity can be achieved. Furthermore, the groove having an approximately V-shape in cross section can improve productivity by making it easier for the base material to flow during molding. Furthermore, the groove having an approximately V-shape in cross section can ensure a large groove depth, and when a grommet is placed in the groove, the thickness and volume of the grommet can be increased, improving durability.

1A and 1B are external views of a badminton racket according to an embodiment, FIG. 1A being a front view of the badminton racket, and FIG. 1B being a side view of the badminton racket. 2A is a schematic cross-sectional view taken along line AA in FIG. 1A, and FIG. 2B is an exploded view of FIG. 2A. FIG. 4 is an enlarged front view of the first grommet. FIG. 2 is a schematic perspective view of a first grommet. 5A is an enlarged front view of the second grommet, FIG. 5B is an enlarged view of the second grommet as viewed from the inside, and FIG. 5C is a schematic perspective view of the second grommet. 6A is a schematic cross-sectional view taken along line BB in FIG. 5A, and FIG. 6B is an exploded view of FIG. 6A. 7A is a cross-sectional view similar to FIG. 2A of a comparative structure, and FIG. 7B is an exploded view of FIG. 7A.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is an external view of a badminton racket according to an embodiment of the present invention, Fig. 1A is a front view of the badminton racket, and Fig. 1B is a side view of the badminton racket. Note that in the following drawings, some components have been omitted for ease of explanation.

As shown in Figure 1, a badminton racket (hereinafter referred to as "racket") 10 comprises a grip 11 held by a player, a shaft 12 that extends in a straight line with one end connected to the grip 11, and an elliptical ring-shaped frame 13 that is connected to the other end of the shaft 12. In other words, the racket 10 comprises, in order in the longitudinal direction, the ring-shaped frame 13, the shaft 12, and the grip 11. Strings 14 are stretched inside the frame 13, and the strings 14 form a striking surface 15 against which the shuttlecock is struck.

In the claims and the description of this specification, unless otherwise specified, the side of the racket 10 in the longitudinal direction where the frame 13 is located is the upper side, and the side where the grip 11 is located is the lower side, as shown by the arrow in Figure 1. The direction perpendicular to the ball-striking surface 15 of the racket 10 is the front-to-back direction. Furthermore, the direction perpendicular to the longitudinal direction on the ball-striking surface 15 (i.e., on a plane along the ball-striking surface 15) is the left-to-right direction, and the left and right sides are based on the view when the front side of the racket 10 is viewed facing forward, as shown in Figure 1A.

The frame 13 has regions that are, from top to bottom in the longitudinal direction, a top portion 13a, a middle portion 13b, and a sleeve portion 13c. The middle portion 13b is a region of a predetermined width that includes the position where the left-right width of the frame 13 is at its maximum, the top portion 13a is the region above the middle portion 13b, and the sleeve portion 13c is the region from the middle portion 13b to the connection position with the shaft 12 below. The top portion 13a, middle portion 13b, and sleeve portion 13c are, although not particularly limited, regions that are approximately 1/3 of the longitudinal length of the frame 13.

A groove 17 is provided on the outer peripheral surface of the frame 13, and multiple holes 13d (not shown in FIG. 1B) are formed around the circumference of the frame 13. Of the multiple holes 13d, a first grommet 30 and multiple second grommets 50 (grommets, not shown in FIG. 1B) are attached to the holes 13d that overlap the grooves 17. Each grommet 30, 50 is attached so as to protrude from the inner circumference of the frame 13, and the string 14 is folded back and passed through each grommet 30, 50, and the string 14 is stretched across the frame 13.

In this embodiment, one first grommet 30 is provided on the upper part of the frame 13, and the second grommets 50 are installed in all of the holes 13d formed by overlapping the grooves 17, in which the first grommets 30 are not installed. Note that this configuration is one example and may be changed, and other examples will be described later.

Next, the cross-sectional shape of the frame 13 will be described below with reference to Figures 2A and 2B. Figure 2A is a schematic cross-sectional view taken along line A-A in Figure 1A, and Figure 2B is an exploded view of Figure 2A. Figures 2A and 2B are cross-sectional views of the frame 13 taken along a plane perpendicular to the extension direction of the frame 13.

As shown in Figures 2A and 2B, the frame 13 is formed by a hollow cylindrical body 18. The thickness of the cylindrical body 18 is set to 0.8 mm or more and 2.0 mm or less, taking into consideration the molding, weight, and rigidity of the frame 13. Although not shown, the cylindrical body 18 may be formed by filling the inside with a specified foam material (not shown). Filling with the foam material may be omitted in part or all of the frame 13. Examples of the foam material include urethane and acrylic.

When viewed in cross section as shown in Figure 2, the frame 13 is provided with a peripheral shape that roughly follows an ellipse with the major axis in the front-to-back direction and the minor axis in the outward-to-inward direction, except for the area where the groove 17 is formed, and both sides in the outward-to-inward direction and both sides in the front-to-inward direction are curved except for the area where the groove 17 is formed. Each hole 13d of the frame 13 is formed to penetrate in the outward-to-inward direction so that the string 14 can pass through.

In the area where the groove 17 of the frame 13 is formed, the cross-sectional shape is formed as shown in FIG. 2 or a cross-sectional shape that is substantially the same as that shown in FIG. 2, although the depth of the groove 17 is slightly different. Also, in the area where the groove 17 is not formed in the sleeve portion 13c of the frame 13 (see FIG. 1), the area where the groove 17 is formed is formed into a cylindrical shape with a cross-section that bulges outward slightly without being recessed in the area where the groove 17 is formed.

Here, in the claims and the description of the specification, unless otherwise specified, the up-down direction on the paper surface of FIG. 2 is the outward-inward direction, with the upper side in the figure being the outer side of the frame 13 and the lower side in the figure being the inner side of the frame 13. The outer side of the frame 13 is formed by the outer forming body 21, and the inner side of the frame 13 is formed by the inner forming body 22, with the middle part of the frame 13 in the outward-inward direction as the boundary. Note that the boundary position between the outer forming body 21 and the inner forming body 22 may be changed as appropriate within the width of the frame 13 in the outward-inward direction.

The groove 17 is formed by the outer forming body 21 so as to be recessed inward, and is formed with an opening 17a on the outside. The groove 17 has a bottom 17b and a first inclined surface 17c and a second inclined surface 17d that sandwich the bottom 17b, and is formed in a roughly V-shape when viewed in cross section as shown in Figure 2.

The bottom 17b of the groove 17 is formed in an arc shape with a center recessed from both sides in the front-back direction when viewed in cross section as shown in Figure 2. The bottom 17b is formed in the central region of the groove 17 in the front-back direction.

The first inclined surface 17c connects the bottom 17b to the edge formed on the front side of the opening 17a, and is inclined so as to be positioned outward as it moves from the bottom 17b to the front side. The second inclined surface 17d connects the bottom 17b to the edge formed on the back side of the opening 17a, and is inclined so as to be positioned outward as it moves from the bottom 17b to the back side.

The groove 17 is formed symmetrically on the front and back. Therefore, the first inclined surface 17c and the second inclined surface 17d are formed symmetrically with respect to a plane that passes through the center of the frame 13 in the front-back direction and is parallel to the outside-inside direction. The first inclined surface 17c and the second inclined surface 17d extend in a substantially straight line when viewed in cross section as shown in Figure 2.

Here, the "approximately straight direction" of the first inclined surface 17c and the second inclined surface 17d refers not only to a direction that extends in a straight line without bending or curving, but also to a direction that is manufactured with the intention of being in a straight line but that differs slightly from the straight line due to processing precision, tolerances, likelihood, etc. Also, the "approximately straight direction" refers to a direction that extends in an arc, but the curvature of the arc is significantly smaller than the curvature of the arc that forms the bottom 17b.

The width W2 of groove 17 in the outward/inward direction is set to 0.17 times or more the width W1 of groove 17 in the front/back direction. By setting width W2 in this range, the depth of groove 17 can be made greater than that of grooves of a conventional structure, which will be described later.

The widths in the front-back direction of the first inclined surface 17c and the second inclined surface 17d are set to be the same. The width W2 in the front-back direction of the groove 17 is set to be 10 times or more the width W3 in the front-back direction of the bottom 17b. The width W1 in the front-back direction of the groove 17 is set to be 4.1 times or more the width W4 in the front-back direction of the bottom 17b. By setting the widths W3 and W4 of the bottom 17b within this range, the range of the bottom 17b becomes smaller, and the ranges of the inclined surfaces 17c and 17d that extend in an approximately linear direction can be relatively increased.

Next, the first grommet (grommet) 30 attached to the frame 13 will be described with reference to FIG. 2, as well as FIG. 3 and FIG. 4. FIG. 3 is an enlarged front view of the first grommet. FIG. 4 is a schematic perspective view of the first grommet. Below, the first grommet 30 arranged in the left-right center of the upper part of the frame 13 (shown by a two-dot chain line) shown in FIG. 3 will be described. In this embodiment, eight strings 14 (eight rows) that pass through the left-right center region of the ball-striking surface 15 (see FIG. 1A) out of the strings 14 extending in the longitudinal direction (see FIG. 1A) are inserted into the first grommet 30.

As shown in FIG. 4, the grommet 30 has multiple (eight in this embodiment) tube portions 31 that are roughly cylindrical, and support portions 32 that extend in the circumferential direction, which is the extension direction of the frame 13, and connect and support each of the tube portions 31. For example, the grommet 30 can be made of a one-piece molded product using a synthetic resin material such as nylon.

Returning to FIG. 2A, the tube portion 31 has a base on the support portion 32 side, and a tip portion on the opposite side to the base is penetrated from the outside of the frame 13 through hole 13d and positioned inside the frame 13. This penetration allows the first grommet 30 to be attached to the frame 13, and in this state, the tip side of the tube portion 31 is arranged to protrude inward from the inner peripheral surface side of the frame 13.

A through hole 33 is formed at a position along the central axis inside the tubular portion 31 and in the support portion 32 on the extension of that line. The string 14 passes through the through hole 33, and the string 14 is folded back at the opening of the through hole 33 on the outer surface side of the support portion 32 so as to pass through the inside of the adjacent tubular portion 31.

The support portion 32 is disposed inside and along the groove 17 as part of the first grommet 30. The support portion 32 is connected to the base of all the tubular portions 31 and is formed in a band shape extending in the extension direction of the frame 13. The width of the support portion 32 in the front-back direction is formed to be larger than the diameter of the hole 13d.

The support portion 32 has a first inner forming surface 35 that is in surface contact with the first inclined surface 17c of the groove 17, a second inner forming surface 36 that is in surface contact with the second inclined surface 17d, and a central forming surface 37 that connects the first inner forming surface 35 and the second inner forming surface 36 and follows the bottom 17b. In other words, the inner forming surface of the support portion 32 that faces the groove 17 is formed in a substantially V-shape along the groove 17 when viewed in cross section as shown in Figure 2. It is preferable that the central forming surface 37 is in surface contact with the bottom 17b, but there may be a partial or total gap between the central forming surface 37 and the bottom 17b.

Furthermore, the support portion 32 has an outer forming surface 38 that is disposed on the opening 17a side of the groove 17 and is exposed to the outside of the frame 13. When viewed in cross section as shown in FIG. 2, the outer forming surface 38 is formed in a curved shape with the center in the front-to-back direction bulging outward. As a result, the outer forming surface 38 is formed parallel to the curved outer peripheral surface of the outer forming body 21 of the frame 13. The outer forming surface 38 may also be formed in a bulging shape that smoothly connects to the outer peripheral surface of the outer forming body 21.

A passage groove 39 (see also FIG. 3) is formed in the area of the outer forming surface 38 of the support portion 32 where the string 14 runs along the outer peripheral surface. In other words, the area of the outer forming surface 38 where the string 14 does not run along the outer peripheral surface is a non-forming area where the passage groove 39 is not formed.

Next, the second grommet 50 will be described with reference to Figures 5 and 6. Figure 5A is an enlarged front view of the second grommet, Figure 5B is an enlarged view of the second grommet from the inside, and Figure 5C is a schematic perspective view of the second grommet. Figure 6A is a schematic cross-sectional view taken along line B-B in Figure 5A, and Figure 6B is an exploded view of Figure 6A.

Here, as shown in FIG. 5A, the second grommet 50 disposed on the right side of the frame 13 (shown by a two-dot chain line) will be described as an example. As shown in FIG. 5A to FIG. 5C, the second grommet 50 is modified from the first grommet 30 (see FIG. 3) mainly by reducing the number of tubular portions 31 by one and shortening the length of the support portions 32, 52 in the circumferential direction of the frame 13. Therefore, in the second grommet 50, the configurations common to the first grommet 30 are given the same reference numerals and descriptions may be omitted.

In the second grommet 50, the length of the frame 13 in the circumferential direction at the support portion 52 is shorter than the distance between adjacent holes 13d (see FIG. 1A) in the circumferential direction, and is slightly larger than the width in the front-back direction. In this embodiment, the support portion 52 is formed in a roughly rectangular shape when viewed from the axial direction of the tube portion 31 (see FIG. 5B).

As shown in Figures 6A and 6B, the outer forming surface 53 of the support portion 52 of the second grommet 50, which is located on the opening 17a side of the groove 17, is formed in a shape that extends in a straight line parallel to the front-to-back direction when viewed in cross section as shown in the figure. The outer forming surface 53 is located slightly inward from the opening 17a and is positioned so as not to protrude outward from the opening 17a.

The functions of the groove 17 and the support portions 32, 52 of each grommet 30, 50 in this embodiment will now be described in comparison with the comparative structure in Figure 7. Figure 7A is a cross-sectional view of the comparative structure similar to Figure 2A, and Figure 7B is an exploded view of Figure 7A. The comparative structure, which is a conventional example, is configured by modifying the shapes of the groove 17 and the support portions 32, 52 in this embodiment, and in Figure 7, the same reference numerals are used for the same configuration as in the embodiment.

In the comparative structure of FIG. 7, the bottom 101b of the groove 101 formed in the frame 100 is formed so as to extend parallel in the front-to-back direction when viewed in cross section as shown in FIG. 7. In addition, in the groove 101, the first inclined surface 101c and the second inclined surface 101d formed on either side of the bottom 101b are formed so as to have a smaller width in the front-to-back direction than the bottom 101b. Therefore, the groove 101 is formed in a generally trapezoidal shape that is longer in the front-to-back direction when viewed in cross section as shown in FIG. 7.

In the comparative structure of Figure 7, the support portion 106 of the grommet 105 has an inner surface facing the groove 101 that is formed in a generally trapezoidal shape along the groove 101 when viewed in cross section as shown in Figure 7. In addition, tapered surfaces are formed on both sides of the outer surface of the support portion 106 in the front and back directions.

Comparing the above embodiment with the conventional structure, the groove 17 of the embodiment can have a greater depth (width in the outward and inward directions) than the groove 101 of the conventional structure. As a result, in a comparison using a structural analysis application, the frame 13 of the embodiment can have greater flexural rigidity and bending rigidity than the frame 100 of the conventional structure. Here, the flexural rigidity refers to the rigidity when a force is applied in the direction in which the frames 13, 100 are pulled via the strings 14 when the striking surface 15 is deformed so as to be concave when hitting the shuttlecock. The bending rigidity refers to the rigidity when a force is applied in the front-to-back direction to the frames 13, 100 when the shuttlecock is hit with the striking surface 15 with the grip 11 side of the racket 10 fixed.

In the embodiment, the rigidity of the frame 13 can be increased, which allows for a lighter feel when hitting the shuttlecock and improves resilience performance. Furthermore, by improving the rigidity of the frame 13 in the embodiment, for example, it is possible to reduce the amount of base material such as resin used in the frame 13 while slightly increasing the rigidity, thereby reducing the weight. Therefore, with the frame 13 in the embodiment, it is possible to achieve both a lightweight frame 13 with high rigidity, thereby improving playing performance. Furthermore, a design can be adopted in which the base material reduced in the frame 13 is relocated to other parts of the racket 10, which also improves performance.

In addition, by increasing the depth of the groove 17 in the embodiment, the thickness and volume of the support parts 32, 52 of each grommet 30, 50 can be increased. This makes it possible to suppress deformation of the support parts 32, 52 and increase durability, even when the string 14 is strung with high tension or when the string 14 is replaced multiple times. Furthermore, by increasing the thickness and volume of the support parts 32, 52, the stress generated by the stringing of the string 14 can be dispersed, which also increases durability.

In addition, the thickness of the support portion 32 of the first grommet 30 is increased, which ensures the depth of the passage groove 39 and prevents the string 14 from protruding from the passage groove 39 or reduces the amount of protrusion, thereby providing good protection for the string 14.

Furthermore, by increasing the thickness of the support portion 32 of the first grommet 30, the top portion 13a of the frame 13 can be locally made heavier. This allows the power to strike the shuttle to be improved while minimizing the overall increase in weight. In addition, the outer forming surface 38 of the first grommet 30 can be formed into a curved shape that bulges outward, reducing air resistance during the swing and improving the swing through.

Here, as another comparative structure, there can be mentioned a configuration in which the groove of the frame is curved and concave in an arc shape in a cross-sectional view. Comparing this configuration with the embodiment, in the embodiment, each inclined surface 17c, 17d extends in a substantially straight line, so that the outer forming body 21 can ensure a width in the front-back direction at the front portion 17e from the first inclined surface 17c and at the back portion 17f from the second inclined surface 17d (see Figure 2). By ensuring such a width, the rigidity of the outer forming body 21 of the frame 13 in the embodiment can be increased.

Another example of a different structure is a rectangular groove that is deeper and narrower in the front-to-back direction than the groove 17 described above, to ensure durability of the grommet. Compared to this configuration, the groove 17 in the embodiment is roughly V-shaped in cross section, which makes it easier for the base material of the frame 13 to flow during molding of the frame 13 using a mold, and also makes it easier to release the frame 13 from the mold. Therefore, the embodiment can achieve better productivity than the rectangular groove described above.

The present invention is not limited to the above-described embodiment, and can be modified in various ways. In the above-described embodiment, the size, shape, direction, etc. shown in the attached drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of its purpose.

The mounting positions and mounting ranges of the two types of grommets 30, 50 on the frame 13 in the above embodiment are merely examples, and various modifications are possible. For example, the first grommet 30 may be omitted, and the second grommet 50 may be mounted in all holes 13d formed in the groove 17. As another example, the number of tubular portions 31 of the first grommet 30 may be increased or decreased to a number other than eight (e.g., 4, 6, 10), or the second grommet 50 may be omitted, and the number of tubular portions 31 of the first grommet 30 may be increased so that the tubular portions 31 of the first grommet 30 are mounted in all holes 13d formed in the groove 17. In such a configuration, the first grommet 30 may have a single support portion 32, or the support portion 32 may be divided into multiple portions in the extension direction of the frame 13.

Compared to the above embodiment, by omitting the first grommet 30 or reducing the number of tubular portions 31 and increasing the number of second grommets 50, the total weight of each grommet 30, 50 can be reduced, resulting in weight reduction around the frame 13. Also, compared to the above embodiment, by increasing the number of tubular portions 31 of the first grommet 30 and lengthening the support portion 32, the rigidity of the mounting portion of the first grommet 30 on the frame 13 can be increased.

Also, as long as the above-mentioned groove 17 is formed at the mounting position of each grommet 30, 50, the formation range of the groove 17 in the frame 13 may be changed. For example, in the above embodiment, the second grommet 50 may be omitted, and a groove 101 of the comparative structure shown in FIG. 7 may be formed in the frame 13 except for the mounting position of the first grommet 30, and a grommet 105 of the comparative structure may be attached to each hole 13d. With such a configuration, the string 14 stretched in the sweet spot of the ball-striking surface 15 is inserted into the tubular portion 31 of the first grommet 30, thereby improving the resilience performance by improving the flexural rigidity.

In addition, when viewed from the axial direction of the tubular portion 31 as shown in FIG. 5B, the shape of the support portion 52 of the second grommet 50 is not limited to a square shape, but can be modified in various ways, for example, to a circle, an ellipse, a polygon, or a square with arc-shaped corners.

In addition, when viewed in cross section as in Figures 2 and 6, the peripheral surface of the frame 13 may have other shapes that form a continuous smooth ring shape except for the area where the groove 17 is formed, such as a curved surface that bulges outward in an arc shape on both the inside-outside and inside-outside and on both the front-back sides.

The bottom 17b of the groove 17, which is recessed in an arc shape in cross section, may be formed by an arc of a single curvature, or may be formed by combining multiple arcs of different curvatures. Furthermore, the bottom 17b may have a shape in which at least a portion is linear. For example, both the connection portion with the first inclined surface 17c and the connection portion with the second inclined surface 17d may be formed in an arc shape, and the portion between these arc-shaped portions may be formed in a straight line.

The present invention relates to a badminton racket that can be easily manufactured while achieving both a lightweight frame and high rigidity, and that can accommodate grommets with enhanced durability in the grooves of the frame.

This application is based on Patent Application No. 2023-214728, filed December 20, 2023, the contents of which are incorporated herein in their entirety.

Claims (7)

A badminton racket having an annular frame, a shaft, and a grip in this order in a longitudinal direction,
The frame includes an outer forming body that forms an outer side in an outer-inner direction, an inner forming body that forms an inner side in the outer-inner direction, and a groove that is recessed inward in the outer forming body and has an opening on the outer side,
The groove includes a bottom, a first inclined surface connecting the bottom and a front edge of the opening, and a second inclined surface connecting the bottom and a rear edge of the opening,
the first inclined surface and the second inclined surface extend in a substantially linear direction when viewed in cross section on a plane perpendicular to the extension direction of the frame,
A badminton racket characterized in that the width of the groove in the front-back direction is set to 4.1 times or more the width of the bottom portion in the front-back direction. The badminton racket of claim 1, characterized in that, when viewed in cross section on a plane perpendicular to the extension direction of the frame, the bottom is formed in an arc shape, and the width of the groove in the outward and inward directions is set to 10 times or more the width of the bottom in the outward and inward directions. The badminton racket of claim 1, characterized in that the groove has a width in the outer-inner direction that is set to be 0.17 times or more larger than the width in the front-back direction. The badminton racket according to claim 1, characterized in that the frame is formed by a hollow cylindrical body, and the thickness of the cylindrical body is set to be 0.8 mm or more and 2.0 mm or less. a grommet disposed partially within the groove;
The grommet includes at least one cylindrical portion and a support portion that is connected to the cylindrical portion and disposed along the groove,
The badminton racket of claim 1, characterized in that the support portion comprises a first inner forming surface in surface contact with the first inclined surface, a second inner forming surface in surface contact with the second inclined surface, a central forming surface that connects the first inner forming surface and the second inner forming surface and runs along the bottom portion, and an outer forming surface that is positioned on the opening side of the groove. The grommet includes a plurality of the cylindrical portions,
The badminton racket according to claim 5, wherein the support portion extends in an extending direction of the frame while being connected to all of the cylindrical portions. The badminton racket according to claim 6, characterized in that the grommet is positioned at least in the center in the left-right direction on the upper part of the frame.

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