JP6535225B2 - Badminton racket - Google Patents

Description

  The present invention relates to a badminton racquet capable of striking a shuttle with striking surfaces on both sides.

  In badminton, a player swings a racket and plays by hitting a shuttle. The racket includes a frame formed in a loop shape, and a string is stretched inside the frame to form a hitting face (see Patent Document 1).

  In badminton play, the shuttle is hit on both the front and back of the ball striking face. This is because the forehand and the backhand make the face of the striking face upside down, or the player changes the grip appropriately to make the face of the striking face face upside down.

JP, 2015-8890, A

  In the frame of a conventional badminton racquet, it is formed of the same material in all areas from front to back. Therefore, various performances (for example, ball holding and repelling of the shuttle, etc.) relating to the hitting of the shuttle are the same whether hit on the front side or the back side of the striking face.

  On the other hand, the preferences for the various performances are different for each player, such as age, gender, and technical level, and even for the same player, they differ depending on the changing season, physical condition and the like. Therefore, conventionally, there has been a problem that the burden of preparing a racket having different performances according to the preferences is required to cope with various preferences.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a badminton racquet which can easily obtain different performances.

The badminton racquet according to the present invention comprises a frame extending in an annular shape, a grip, a shaft connecting the frame and the grip, and a string stretched on the frame to form a striking surface on both front and back surfaces. A badminton racquet, wherein the frame includes a front surface side forming body forming a front surface portion and a rear surface side forming body forming a rear surface portion, one of the front surface side forming member and the rear surface side forming member is A different material from the other, and the different material is a molded product obtained by molding a prepreg-like fiber reinforced resin sheet mainly composed of carbon fibers, the front surface-side formed body and the back surface-side formed body It is characterized in that it is disposed as a layer that fits within the thickness in any one of the above.

  According to this configuration, since the materials are different between the front surface side formation body and the back surface side formation body surface portion, it is possible to change the performance regarding the hitting when hitting the shuttle with the front surface and the back surface of the striking face. As a result, it is possible to easily exhibit two different types of performance with one racket simply by changing the grip.

In the present invention, the different materials are set to have a flexural strength of 1800 MPa or more and 2000 MPa or less, a flexural modulus of 155 GPa or more and 175 GPa or less, and one of the surface side formed body and the back side formed body which does not contain the different material. The material of is preferably set to have a flexural strength of 1600 MPa or more and less than 1800 MPa and a flexural modulus of 135 GPa or more and less than 155 GPa .

Further, in the present invention, any one of the front surface portion and the rear surface portion may have a flat portion substantially parallel to the surface direction of the ball striking face . Further, in the present invention, either the front surface portion or the rear surface portion is a curved surface portion bulging in the front and back direction, and is continuous with both the outer and inner sides of the curved surface portion and extends in a direction away from each other It is good to have an existing slope part.

  Further, in the present invention, it is preferable that a wire extending in the extending direction of the frame is provided within the thickness on the front surface side or the back surface side of the frame.

  According to the present invention, since the front side formation body and the back side formation body surface portion are formed of different materials, different performances can be easily obtained on the front side and the rear side of the ball striking face.

It is an external view of the racket which concerns on embodiment of this invention, FIG. 1A is a rear view of the said racket, FIG. 1B is a side view of the said racket. It is the AA line schematic sectional drawing of FIG. 1 for demonstrating the shape of a flame | frame. It is the BB line schematic sectional drawing of FIG. 1 for demonstrating the shape of a flame | frame. It is a BB line schematic sectional drawing of FIG. 1 for demonstrating the material of a flame | frame. It is a partial rear view for explaining coloring of the above-mentioned racket. It is a partial side view for explaining coloring of the above-mentioned racket. FIG. 7 is a partial side view showing the racket of FIG. 6 in a reversed state. It is a partial perspective view for explaining coloring of the above-mentioned racket. It is a fragmentary perspective view which shows the state which inverted the racket of FIG. 10A and 10B are cross-sectional views of the frame according to the first embodiment, and FIG. 10C is a cross-sectional view of the frame according to the comparative example. FIG. 7 is a cross-sectional view of a frame in accordance with a second embodiment. FIG. 14 is an explanatory view of an experiment for measuring the bending amount of the racket according to the second embodiment.

  Hereinafter, embodiments of the present invention will be specifically described 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 rear view of the badminton racket, and FIG. 1B is a side view of the badminton racket. In the following drawings, part of the configuration is omitted for convenience of explanation.

  As shown in FIG. 1, a badminton racquet (hereinafter referred to as "racquet") 10 has a grip 11 held by a player, and a cylindrical shaft 12 having one end connected to the grip 11 and extending in a linear direction. And an oval annular frame 13 connected to the other end of the shaft 12. A string 14 is stretched on the inside of the frame 13, and this string 14 forms a striking face 15 on which the shuttle is struck. The shaft 12 and the frame 13 are colored or the like, which will be described later.

  In the claims and the description of the present specification, unless indicated otherwise, as shown by arrows in FIG. 1, in the longitudinal direction of the racket 10, the side on which the frame 13 is located is taken as the tip side, and the grip 11 is The side where it is positioned is the rear end side. The direction orthogonal to the striking face 15 is referred to as the front and back direction, the front side of the paper surface of FIG. 1A (left side of the paper surface of FIG. 1B) is the back side, and the opposite side is the front side. Furthermore, on the ball striking face 15 (that is, on a plane along the ball striking face 15), the direction orthogonal to the longitudinal direction is left and right, and the left and right sides are viewed with the back of the racquet 10 in front as shown in FIG. Time of day as a standard.

  The ball striking face 15 formed by the strings 14 is formed on both the front side and the back side. In badminton play, there are cases in which the player strikes with the forehand and the case with the backhand. When the shuttle flies to the hand holding the racket 10 and the shuttle flies to the side opposite to the hand holding the racket 10 It is common to hit with a hand. And, due to the nature of the badminton swing, the striking face 15 on which the shuttle is hit is opposite between the forehand and the backhand.

  The frame 13 is provided with areas that become the top portion 13a, the middle portion 13b, and the sleeve portion 13c in order from the front end side to the rear end side in the longitudinal direction. The middle part 13b is a predetermined width area including the position W at which the horizontal width of the frame 13 is maximum, the top part 13a is a front end side area from the middle part 13b, and the sleeve part 13c is a rear end side from the middle part 13b. It becomes an area to the connection position with the shaft 12. The top portion 13a, the middle portion 13b, and the sleeve portion 13c are not particularly limited, but are approximately 1/3 of the length in the longitudinal direction of the frame 13.

  A groove 17 is provided on the outer peripheral surface of the frame 13 at a position in the longitudinal direction from the top 13a to the middle 13b. At the bottom of the groove 17, the string 14 (not shown in FIG. 1B) is folded back and passes, so that the string 14 contacts the floor even if the longitudinal end of the frame 13 hits or rubs against the floor To prevent

  Next, the cross-sectional shape of the frame 13 will be described below with reference to FIGS. 2 and 3. 2 is a schematic cross-sectional view taken along line A-A of FIG. 1 for explaining the shape of the frame, and FIG. 3 is a schematic cross-sectional view taken along line B-B of FIG. 1 for explaining the shape of the frame. 2 and 3 are cross-sectional views of the frame 13 in a plane perpendicular to the extending direction of the frame 13. As shown in FIGS. 2 and 3, the frame 13 is formed by filling a predetermined foam material 19 inside a hollow cylindrical portion 18 having a predetermined thickness. The filling of the foam material 19 may be omitted in part or all of the frame 13. As a material of the foam material 19, urethane, an acryl type, etc. can be illustrated. The specific configuration within the thickness of the cylindrical portion 18 will be described later.

  In the top portion 13a and the middle portion 13b of the frame 13 shown in FIG. 1, the cross-sectional shape shown in FIG. 2 or the slightly different cross-sectional shape shown in FIG. Further, in the range of the tip end side from the line B-B where the groove portion 17 is not formed in the middle portion 13b and the skirt portion 13c of the frame 13, the cross-sectional shape shown in FIG. It is formed.

  Here, in the claims and the description of the present specification, unless otherwise specified, when the central axis position of the insertion hole 13d through which the string 14 (see FIG. 1A) is inserted is the boundary position B1, the boundary position The exposed surface of the frame 13 located on the front side from B1 is referred to as a surface portion 20. Further, the exposed surface of the frame 13 located on the back side from the boundary position B1 is referred to as a back surface portion 21. Further, the vertical direction in the sheet of FIG. 2 and FIG. 3 is an outer / interior direction, the upper side in the figure is the outer side of the frame 13, and the lower side in the figure is the inner side of the frame 13. The boundary position B1 may be appropriately changed within the thickness of the frame 13.

  In the cross-sectional views of FIG. 2 and FIG. 3, the front surface portion 20 and the back surface portion 21 of the frame 13 are formed in an asymmetrical shape. Here, asymmetry means that the front surface portion 20 and the back surface portion 21 do not become symmetrical when viewed from the boundary position B1 as a symmetry axis, and also in FIG. 2 and FIG. It means that it does not become the same shape as compared with the shape made to do. The surface 20 and the back 21 have different widths in the front and back direction, and the width of the back 21 is larger.

  The surface part 20 is formed in the shape provided with the plane part 25 and the curved surface part 26 connected on both sides of this plane part 25 outside and inside. The flat portion 25 is directed substantially parallel to the outer and inner direction (the surface direction of the ball striking face 15), and is formed in a flat shape or a shape in which the outer and inner direction central portion is slightly expanded. The flat surface portion 25 is formed in a region corresponding to the center portion divided into three when the surface portion 20 is equally divided into three in the outward and inward directions. The curved surface portion 26 is a curved surface formed in a quarter arc shape in a cross sectional view, and an end opposite to the flat portion 25 is directed to the back side.

  The back surface portion 21 is formed in a shape including an arc-shaped surface portion 27 to be a curved surface portion and inclined surface portions 28 connected to both the outer and inner sides of the arc-shaped portion 27. The arc-shaped surface portion 27 presents a curved surface in a quarter arc shape formed so that the center portion in the outer and inner directions bulges in the back most direction in a cross sectional view. The most bulging position of the arc-shaped surface portion 27 is set outside the middle in the outer and inner direction of the frame 13. Each sloped surface portion 28 is formed substantially flat and extends in a direction away from each other toward the front side. The outer and inner ramps 28 extend tangentially at the outer and inner ends of the arcuate surface 27.

  In the surface part 20 and the back part 21 of the area to be the cross section of FIG. 3, the outer and inner peripheral surfaces of the frame 13 straddling the boundary position B1 are smoothly curved so that the center in the front and back direction bulges. It is formed as. The curvatures of the curved surface portion 26, the arc-shaped surface portion 27, and the bulging surfaces 30 and 31, which are curved surfaces, are set larger in the order of the arc-shaped surface portion 27, the curved surface portion 26, and the bulging surfaces 30 and 31. In the area to be the cross section of FIG. 2, the groove 17 is formed in the area corresponding to the outer bulging surface 30, and the inner bulging surface 31 of FIG. 2 and the inner bulging surface 31 of FIG. Be done.

  According to the above-described shape, since the surface portion 20 and the back surface portion 21 are formed in an asymmetrical shape, the stress distribution and the cross-sectional shape which occur when the hitting ball on the hitting face 15 is the front side and the back side. The amount of deformation and the shape of deformation are different. Further, it is possible to change the second moment of area for bending deformation and the like of the frame 13 depending on whether the hitting ball on the hitting face 15 is on the front side or on the back side. As a result, on the front and back of the striking face 15, the time when the shuttle contacts the striking face 15 can be changed, the resilience performance, and the like can be changed, and the performance on impact such as ball holding and repelling performance can be changed. As a result, two different types of performance can be easily exhibited with one racket 10 without changing the racket 10 simply by changing the grip 11 by the player, and it is possible for the player to have different preferences such as age, gender and technical level. Can be easily coped with.

  Here, when considering badminton play further, in the comparison between the forehand and the backhand, the forehand tends to have a high shuttle speed because the shuttle is quickly dropped onto the court, and the swing speed is accordingly high. , Swing trajectory tends to be long. On the other hand, the backhand tends to have a shorter swing path, and in many cases, it is likely to strike the shuttle to a course hard for the opponent to hit.

  However, as in the conventional badminton racquet, if the front and back parts of the frame are symmetrical, even if the forehand and backhand require different types of batting as described above, the same performance as the frame is required. I have no choice but to demonstrate. That is, designing the frame shape to the performance according to the forehand degrades the backhand performance, and conversely, designing the frame shape to the performance according to the backhand degrades the forehand performance. There is.

  In this respect, with the frame 13 of the present embodiment, different ball holding and repelling performance can be realized on the front and back of the hitting face 15, and the performance improvement according to the properties of both the forehand and the backhand as described above Can be

  In addition, by forming the front surface portion 20 and the back surface portion 21 in an asymmetrical shape, it is possible to change the air resistance received by the frame 13 between the forehand and the backhand, which also enables both the forehand and the backhand to It can be expected to improve the performance according to the nature.

  Subsequently, the material of the frame 13 will be described below with reference to FIG. FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 1 for explaining the material of the frame. Here, as shown in FIG. 4, the cylindrical portion 18 of the frame 13 is composed of a front surface side forming body 35 forming the front surface portion 20 and a back surface side forming body 36 forming the back surface portion 21. One of the front surface side formed body 35 and the back surface side formed body 36 is formed to include a bending suppression portion 37 as a material different from the other side. In the present embodiment, the bending suppression portion 37 is disposed as a layer that fits within the thickness in the region corresponding to the flat surface portion 25 and the inside and outside curved surface portion 26 in the front surface side formed body 35.

  The wire 38 is disposed at the most bulging position of the arc-shaped surface portion 27 in the back surface side formed body 36. The wire 38 is for enhancing the flexural modulus and hardness of the frame 13 and may be made of titanium, stainless steel, boron or the like.

  In forming the cylinder portion 18, after forming a cylinder of a resin sheet, the cylinder is curved in an annular shape, and then installed in a mold and then heated and pressed, the mold is formed. Shape it. The cylinder of the resin sheet is formed by laminating a plurality of carbon prepreg sheets (prepreg-like fiber reinforced resin (FRP) mainly composed of carbon fibers, hereinafter referred to as “main sheet”) mainly forming the cylinder portion 18 , Formed by cylindrical winding. In this lamination, the bending suppression portion 37 is formed between the plurality of main sheets so that the bending suppression portion 37 is disposed in a region corresponding to the flat surface portion 25 and the outside curved surface portion 26 after molding. A band of carbon prepreg sheet is interposed. In addition, the wire 38 is interposed between the plurality of main sheets so that the wire 38 is disposed in a region corresponding to the arc-shaped surface portion 27 after molding. As a result, in the frame 13 after molding, the bending suppression portion 37 is formed within the thickness of the front surface side formed body 35, and the wire 38 is disposed within the thickness of the back surface side formed body 36.

  Here, the carbon prepreg sheet forming the bending suppression portion 37 becomes a molded body having a bending strength of 1800 MPa to 2000 MPa and a bending elastic modulus of 155 GPa to 175 GPa after molding. When a plurality of carbon prepreg sheets forming the bending suppression portion 37 are used, the bending strength and the bending elastic modulus of the sheets may be the same or different as long as they are within the above range. Good. In addition, the main sheet becomes a formed body having a flexural strength of 1600 MPa or more and less than 1800 MPa and a flexural modulus of 135 GPa or more and less than 155 GPa after molding. The bending strength and the bending elastic modulus may be the same or different from each other as long as the plurality of main sheets are within the above range.

  Here, in the conventional badminton racquet, which is made of the same material on the front and back of the frame 13, as in the case described above, even if a batted ball having different properties from the forehand and the backhand is required, the same performance as the frame is obliged . In this respect, by providing the bending suppression portion 37 and the wire 38 in the frame 13, the bending strength and the bending elastic modulus of the frame 13 change depending on whether the hitting ball on the hitting face 15 is on the front side or on the back side. The bending amount of the frame 13 can be changed. Therefore, this also makes it possible to change the performance on impact, such as ball holding and repelling performance as described above, on the front and back of the striking face 15. As a result, it is possible to easily exhibit two different types of performance with one racket 10 without changing the racket 10, and it is possible to improve the performance according to the properties of both the forehand and the backhand.

  Further, the combination of the shape in which the front surface portion 20 and the back surface portion 21 of the frame 13 are asymmetrical, and the provision of the bending suppression portion 37 can synergistically increase the variation in the performance regarding striking.

  The coloration of the shaft 12 and the frame 13 will then be described below with reference to FIGS. 5 to 9 are diagrams for explaining their coloring, FIG. 5 is a partial rear view of the racket, FIG. 6 is a partial side view of the racket, and FIG. 7 is an inverted racket of FIG. It is a partial side view showing a broken state. 8 is a partial perspective view, and FIG. 9 is a partial perspective view showing the racket of FIG. 8 in a reversed state.

  In the shaft 12 and the frame 13, the three colors of the first colored portion 41, the second colored portion 42, and the main colored portion 43 that is most of the area other than the first colored portion 41 and the second colored portion 42 are mainly used. It is color-coded. Therefore, the first colored portion 41 and the second colored portion 42 are also exposed as a pattern or a pattern on the shaft 12 and the frame 13. In FIGS. 5 to 9, for convenience of illustration, the area with halftone dots is the first colored section 41, the area with black is the second colored section 42, and the area with white (the color of the paper) is the main color. It is referred to as part 43. In addition, the actual coloring may be any color as long as the colored portions 41 to 43 have different colors, and the first colored portion 41 may be orange, the second colored portion 42 may be green, and the main colored portion 43 may be black. It can be illustrated.

The first colored portion 41 is formed in five regions of the shaft 12 and the frame 13 in the present embodiment. Assuming that the five areas are the 1-1st colored part 41a to the 1st-5 colored part 41e for convenience of explanation, when the racket 10 is viewed from the back side as shown in FIG. become that way.
1-1 colored portion 41a: right side surface of shaft 12 1-2 colored portion 41b: outer side surface behind position W in right half of frame 13 1-3 colored portion 41 c: right half portion of frame 13 The first to fourth colored portions 41d: the inner side surface behind the position W in the left half of the frame 13. the first to fifth colored portions 41e: the positions in the first half of the left half of the frame 13 side

  The first-first colored portion 41 a is formed in a range that does not extend leftward from the center position in the left-right direction of the shaft 12 and that the first colored portion 41 a fits on the right side of the center position. In the present embodiment, the first-first colored portion 41a is formed near the front end and the rear end of the shaft 12, and the main colored portion 43 is provided between them. Further, in the first-first colored portion 41a, the length of the portion exposed to the rear end side is longer than that of the portion exposed to the front end side.

  The first and second colored portions 41 b and the first and third colored portions 41 c are provided on the right half of the frame 13, in other words, on the right side which is one side of the shaft 12. The first to third colored portions 41 b and the first to third colored portions 41 c do not protrude inside the center position of the frame 13 in the outer and inner directions, and are formed in a range that fits outside the center position. In the present embodiment, the first and second colored portions 41 b and the first and third colored portions 41 c extend in the extending direction of the frame 13 and are provided such that the main colored portion 43 appears between them. . In addition, the main colored portion 43 appears also between the rear end of the first and second colored portions 41 b and the rear end of the frame 13 and between the tip of the first and third colored portions 41 c and the leading end of the frame 13. It is provided.

  The first to fourth colored portions 41 d and the first to fifth colored portions 41 e do not protrude outside the center position of the frame 13 in the outer and inner directions, and are formed in a range that fits inside the center position. In the present embodiment, the first to fourth colored portions 41 d and the first to fifth colored portions 41 e extend in the extending direction of the frame 13 and are provided such that the main colored portion 43 appears between them. . In addition, the 1-4 colored portion 41 d is divided into three, and the main colored portion 43 appears between them, and also between the rear end of the 1-4 colored portion 41 d and the end of the frame 13 The main colored portion 43 is provided to appear. Furthermore, a main colored portion 43 is provided so as to appear between the tip of the first to third colored portion 41 c and the leading end of the frame 13.

  The second colored portion 42 in the present embodiment is formed in a region symmetrical to the first colored portion 41 with the center position (axial center position) of the shaft 12 in the left-right direction as the symmetry axis S. Therefore, if the second colored portions 42 are also formed in five regions, and the five regions are referred to as the 2-1st colored portion 42a to the 2-5th colored portion 42e for the convenience of explanation, the formation regions thereof are The first colored portion 41 a to the first to fifth colored portion 41 e are formed symmetrically with respect to the symmetry axis S, respectively. In other words, when the racket 10 is turned upside down from the state shown in FIG. 1, the 2-1st colored part 42a is formed in the area where the 1-1st colored part 41a to the 1-5th colored part 41e are formed before the inversion. The fifth to fifth colored portions 42e are disposed. Therefore, the description of the formation regions of the (2-1) th colored portion 42a to the (2-5) th colored portion 42e will be omitted here.

  When the racket 10 is viewed at a predetermined angle that is nonparallel and non-orthogonal to the ball striking face 15, for example, when the racket 10 is viewed as shown in FIG. The first colored portion 41 is exposed in the half area. While this looks like, the main colored portion 43 appears to be exposed in the remaining about half area, and the second colored portion is hidden. Therefore, the player looks like a two-color racket 10 of the first colored portion 41 and the main colored portion 43. At this time, the lower side of the frame 13 and the hitting face 15 in the drawing of FIG. It can be identified as

  On the other hand, when the grip 11 is changed from the state shown in FIG. 8 and the racket 10 is rotated 180 degrees around the axis of the shaft 12 (the hitting face not shown is reversed), the state shown in FIG. At this time, the player appears that the second colored portion 42 appears in approximately half of the shaft 12 and the frame 13 while the main colored portion 43 appears in the remaining approximately half of the area. The colored part is in a state of hiding. Therefore, the player looks like a two-color racket 10 of the second colored portion 42 and the main colored portion 43, and in this case, the lower side of the frame 13 and the hitting face 15 in FIG. It can be identified as

  In addition, when it is rotated by ± 90 ° around the axis of symmetry S from the state shown in FIG. 5, the state shown in FIGS. 6 and 7 is obtained, and either one of the first colored portion 41 and the second colored portion 42 It will be in a hidden state. It is preferable that the angle at which any one of these is hidden is within a range of ± 20 ° rotation about the axis of symmetry S from the state shown in FIGS. 6 and 7.

  The first colored portion 41 and the second colored portion 42 illustrated in FIGS. 5 to 9 are merely examples, and various modifications are possible as long as the front and back can be identified as described above. For example, at least one of the above-mentioned five places of the first colored part 41 and the second colored part 42 in each of the colored parts 41 and 42 may be provided, and the shapes in each of the five places are also illustrated. It is not limited to the example shown. Further, for example, the first and second colored parts 41 b and the first to third colored parts 41 c may be connected, or the first to fourth colored parts 41 d and the first to fifth colored parts 41 e may be connected.

  Furthermore, the color of the first colored portion 41 and the second colored portion 42 may be displayed as a pattern using a plurality of similar colors in addition to being single colors. In addition, when the player sees the first colored portion 41 and the second colored portion 42 at a predetermined angle, it is not necessary to completely hide the first colored portion 41 and the second colored portion 42. Good. Furthermore, in each colored part 41-43, it does not prevent that a character, a mark, a logo, a pattern, a pattern, etc. are given. Moreover, when using the grommet, each of the colored portions 41 to 43 in the frame 13 may color the grommet.

  As described above, since the colored portions 41 to 43 are provided in the racket 10, the player can easily identify the front and back of the striking face 15 depending on whether the first colored portion 41 and the second colored portion 42 can be seen. It is possible to easily select which striking face 15 strikes. Therefore, as described above, in the case where the performance (ball holding performance and the repelling performance) with regard to striking differs between the front and back of the striking face 15, the player can easily use different performances during playing and rally.

  Further, the design of the racket 10 can be largely changed between the state of FIG. 8 and the state of FIG. 9, and two different designs can be easily represented by one racket 10. As a result, the appearance and impression of the racket 10 seen from the player can be largely changed, and even if the preference of the player regarding the design changes, this can be easily coped with. Note that the view from the above-mentioned player also differs depending on the hand holding the racket 10 (right hand or left hand).

  Subsequently, analysis (simulation) performed to evaluate the ball holding and the repelling performance of the racket according to the above-described embodiment will be described with reference to FIG. 10A and 10B are cross-sectional views of the frame according to the first embodiment, and FIG. 10C is a cross-sectional view of the frame according to the comparative example. In this analysis, the racket of Example 1 is a racket having the same shape as that illustrated in the above-described embodiment, and provided with a frame 13 having a cross-sectional shape shown by a two-dot chain line in FIGS. 10A and 10B. However, the material of the racket according to the first embodiment is the frame 13 formed of the above-described main sheet without using the above-described bending suppression portion 37 and the wire 38 (see FIG. 5). The racket of the comparative example has the same configuration and conditions as the example 1 except that the cross-sectional shape of the frame 13 'is changed to the shape shown by a two-dot chain line in FIG. 10C. The frame 13 'of the comparative example has a front and back symmetrical shape similar to an ellipse in a cross sectional view, and has a shape in which only the upper half in FIG.

  Using the racket of Example 1 and the racket of the comparative example, analysis of cross-sectional displacement and stress distribution of the frames 13 and 13 'at the time of hitting was performed. In the cross-sectional displacement simulation, the cross-sectional shape when load F was applied was determined on the assumption that the sweet spot of the striking face was hit by the shuttle at a predetermined relative speed. In the racket of Example 1, simulations were performed both when hitting the shuttle on the front side of the hitting face, that is, on the left side in FIG. 10A and when hitting the shuttle on the rear side of the hitting face, that is, on the right in FIG. In the racket of the comparative example, a simulation was conducted in the case where the shuttle was hit on the left side in FIG. In FIGS. 10A to 10C, the solid line indicates the simulation result of the cross-sectional shape when the maximum displacement is given by each impact, and the relative value of the maximum displacement in Example 1 where the value of the maximum displacement of the comparative example is 100 is shown. It shows in Table 1 below.

  Similarly, the stress distribution of the frames 13 and 13 'at the time of impact was also determined, and the maximum stress at which the stress was largest was determined. The relative value of the maximum stress in Example 1 in which the value of the maximum stress in the comparative example is 100 is shown in Table 1 below.

  As can be understood from the results of Table 1, hitting on the front side has larger maximum stress and maximum displacement than hitting on the back side. This makes it possible for the player to feel the difference in ball holding performance and repelling performance on the front and back of the hitting face.

  Subsequently, an experiment carried out to evaluate the bending performance of the racket according to the above embodiment will be described. In this experiment, as Example 2, a racket provided with a frame having a cross-sectional shape shown in FIG. 11 was manufactured. FIG. 11 is a cross-sectional view of a frame according to a second embodiment. The frame 13 of Example 2 has a front and back symmetrical shape, and the back side and the front side are formed in the same shape as the surface portion 20 (see FIG. 2) of the above embodiment. Moreover, although the flame | frame 13 of Example 2 was set as the structure containing the bending suppression part 37 mentioned above, it shape | molded, without using the wire 38 and the foam material 19. FIG. The bending suppression portion 37 is set to have a bending strength of 1800 MPa or more and 2000 MPa or less, and a bending elastic modulus of 155 GPa to 175 GPa, and a portion formed of a main sheet other than the bending suppression portion 37 has a bending strength of 1600 MPa or more The bending elastic modulus was set to less than 1800 MPa and less than 135 GPa and less than 155 GPa.

  FIG. 12 is an explanatory view of an experiment for measuring the bending amount of the racket according to the second embodiment. As shown in FIG. 12, in the present experiment, the grip 11 of the racket 10 is fixed, a predetermined load F is applied to the tip end side of the frame 13, and front and back directions in the tip of the frame 13 with respect to before the load F is applied. The amount of deformation was measured as the amount of bending. This measurement was performed for both of the case where the load F was applied from the front side of the frame 13 and the case where the load F was applied from the rear side. In this measurement, when the value of the bending amount when the load F is applied from the front side is 100 (see FIG. 12A), the relative value of the bending amount when the load F is applied from the back side is 102 to 105 (figure 12 B)).

  As can be understood from the above measurement results, when the deflection suppressing portion 37 is disposed on the side where the load F is applied (the direction in which the shuttle is hit), compared to the case where the deflection suppressing portion 37 is disposed on the opposite side, The amount of bending decreases. Therefore, hitting the ball on the front side can realize the power improvement and the ball holding by crushing the shuttle at the time of hitting by the action of the high-flexure deflection suppressing portion 37.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. In the above embodiment, the size, shape, direction, and the like shown in the attached drawings are not limited to the above, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, without departing from the scope of the object of the present invention, it is possible to appropriately change and implement.

  For example, the distinction between the front and back in the racket 10 may be opposite to that of the above-described embodiment, and in the direction orthogonal to the hitting face 15, either one may be the front and the opposite may be the back.

  In addition, the shape viewed in cross section in a plane orthogonal to the extending direction of the frame 13 may be changed. For example, in a cross-sectional view of the frame 13, a plurality of projecting portions in the front and back direction may be formed, or a recessed portion may be formed.

  Moreover, the formation position of the bending suppression part 37, the formation range, and the number of installation are not restricted to the structure shown in FIG. 4, A various change is possible. For example, the bending suppression portion 37 may be provided separately in the outer and inner directions, may be provided only in the flat portion 25 without being provided in the curved surface portion 26, or may be provided in a plurality of layers in the thickness direction of the cylindrical portion 18.

  The bending suppression portion 37 and the wire 38 may be provided continuously in all the extending directions of the frame 13 or may be provided in a part of the extending direction.

  Also, the shape of the frame 13 may be changed to a cross-sectional shape that is symmetrical on the front and back sides. Moreover, it is good also as a design which does not give coloring like each coloring part 41-43.

  The present invention relates to a badminton racquet which can easily obtain different performances on the front and back sides of a hitting face.

10 rackets (badminton rackets)
11 grip 12 shaft 13 frame 13 d insertion hole 14 string 15 striking surface 20 surface portion 21 back surface portion 25 flat surface portion 27 arc-shaped surface portion (curved surface portion)
35 front side formation body 36 back side formation body 37 bending suppression portion 41 first colored portion 42 second colored portion

Claims (5)

A badminton racquet comprising: an annularly extending frame; a grip; a shaft connecting the frame and the grip; and a string stretched on the frame to form a striking surface on both front and back surfaces,
The frame includes a front side formed body forming a front side and a back side formed body forming a back side, and either one of the front side formed body and the back side formed body is different from the other side. Formed including materials ,
The different material is a molded product obtained by molding a prepreg-like fiber-reinforced resin sheet mainly composed of carbon fibers, and is disposed as a layer that fits within the thickness on any one of the front surface side and the back surface side. A badminton racket characterized by being installed . The different materials are set to have a flexural strength of 1800 MPa to 2000 MPa and a flexural modulus of 155 GPa to 175 GPa ,
Among the surface side formed body and the back side formed body, the material not including the different material has a bending strength set to 1600 MPa or more and less than 1800 MPa, and a bending elastic modulus of 135 GPa or more and less than 155 GPa. The badminton racket according to claim 1. The badminton racquet according to claim 2 , wherein any one of the front surface portion and the back surface portion has a flat portion substantially parallel to a surface direction of the hitting face . The other one of the front surface portion and the back surface portion has a curved surface portion bulging in the front and back direction, and an inclined surface portion connected to both the outer and inner sides of the curved surface portion and extending in a direction away from each other as being away from the curved surface portion badminton racquet according to any one of claims 1 to 3, characterized in that it comprises. The wire rod extended in the extension direction of the said flame | frame is provided in the thickness in the surface side or back surface side of the said flame | frame, The badminton racquet in any one of the Claims 1-4 characterized by the above-mentioned.

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