JP2017121431A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket frame for tennis that has good repulsion performance and spin performance.SOLUTION: A racket frame comprises a face part 1, a grip part 3, and a shaft part 2 arranged between the face part and the grip part. The face part comprises an outer periphery, an inner periphery, a first end arranged on the side of the shaft part, a second end on the side opposite to the first end, and a side part 11 arranged between the first end and the second end. The side part does not comprise a groove 12 on the side of the outer periphery.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a racket frame, and more particularly to a racket frame for tennis.

  The rebound performance and the spin performance have been used as evaluation indexes for the performance of a conventional tennis racket frame. Conventionally, in order to improve the resilience performance and spin performance of a tennis racket frame, the bending rigidity of the tennis racket frame has been improved.

  A conventional racket frame for tennis has a face portion including a side portion, a shaft portion, and a grip portion. In the conventional tennis racket frame, a groove is provided on the outer peripheral side of the face portion including the side portion (for example, Patent Document 1).

JP 2003-93548 A

  The inventors of the present invention have newly found that the torsional frequency of the face portion has a strong positive correlation with the resilience performance and spin performance of a tennis racket frame. A conventional racket frame for tennis has a torsional rigidity because a groove is provided on the outer peripheral side of the face part including the side part.

  Advanced tennis players tend to prefer thin tennis racket frames with emphasis on the swingability of the racket frame. In such a case, the reduction in resilience performance and spin performance accompanying the reduction in torsional rigidity is particularly significant.

  The present invention has been made in view of these points. Specifically, an object of the present invention is to provide a tennis racket frame having good resilience performance and spin performance.

  The racket frame according to the present invention includes a face portion, a grip portion, and a shaft portion disposed between the face portion and the grip portion. The face portion includes an outer periphery, an inner periphery, a first tip disposed on the shaft portion side, a second tip opposite to the first tip, and between the first tip and the second tip. And arranged side portions. The side portion does not have a groove on the outer peripheral side.

  According to the racket frame according to the present invention, the resilience performance and spin performance of the racket frame can be enhanced.

It is a top view of the racket frame concerning a 1st embodiment. It is a side view of the racket frame concerning a 1st embodiment. It is sectional drawing in the III-III cross section of FIG. It is sectional drawing in the IV-IV cross section of FIG. It is a figure which shows the structure of the side part of the racket frame which concerns on 1st Embodiment. It is sectional drawing in the side part of the racket frame which concerns on a comparative example. It is sectional drawing of the side part in the state by which the bumper was mounted | worn with the side part of the racket frame which concerns on 1st Embodiment. It is sectional drawing of the side part of the racket frame which concerns on 2nd Embodiment. It is an internal structure figure of the side part of the racket frame which concerns on 2nd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals. Moreover, you may combine arbitrarily at least one part of embodiment described below.

(First embodiment)
Hereinafter, the structure of the racket frame according to the first embodiment will be described first.

  FIG. 1 is a diagram illustrating a structure of a racket frame according to the first embodiment. As shown in FIG. 1, the racket frame according to the first embodiment has a face part 1, a shaft part 2, and a grip part 3. The shaft portion 2 is disposed between the face portion 1 and the grip portion 3.

  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) can be used.

  The face portion 1 has, for example, an elliptical shape in plan view. The face portion 1 has a first tip 1a and a second tip 1b. The first tip 1 a is an end of the face portion 1 on the shaft portion 2 side. The second tip 1b is the end of the face portion 1 opposite to the first tip 1a. The face portion 1 has an inner periphery 1c and an outer periphery 1d.

  The face portion 1 has a maximum width Wmax. The face portion 1 has a side portion 11. The side part 11 is provided on the side peripheral part of the face part 1. The side peripheral portion is provided in a portion between the first tip 1a and the second tip 1b in the face portion and including a portion having the maximum width Wmax. More specifically, the side portion 11 has a position at a distance L1 from the first tip 1a in the extending direction of the racket frame and a position at a distance L2 from the second tip 1b in the extending direction of the racket frame. It is provided in between.

  The ratio of the distance L to the distance L1 between the first tip 1a and the second tip 1b is preferably 0.25 or less. The ratio of the distance L to the distance L2 is preferably 0.25 or less.

  FIG. 2 is a side view of the racket frame according to the first embodiment. FIG. 3 is a cross-sectional view of a surface perpendicular to the circumferential direction of the side portion 11 in the racket frame according to the first embodiment. FIG. 4 is a cross-sectional view of a surface perpendicular to the circumferential direction in a portion other than the side portion 11 in the racket frame according to the first embodiment. FIG. 3 corresponds to the III-III cross section in FIG. 4 corresponds to the IV-IV cross section in FIG.

  As shown in FIGS. 2 and 3, in the side portion 11, the groove 12 is not formed along the circumferential direction on the outer periphery 1 d side of the face portion 1. On the other hand, as shown in FIGS. 2 and 4, a groove 12 is formed on the outer periphery 1 d side of the face portion 1 except for the side portion 11.

  As shown in FIG. 2, the face portion 1 has a thickness T. The thickness T of the face portion 1 is preferably 15 mm or more and less than 30 mm. More preferably, the thickness T of the face portion 1 is not less than 17 mm and less than 22 mm.

  A hole 13 is provided in the face portion 1. The hole 13 penetrates the face portion 1 from the inner circumference 1c side toward the outer circumference 1d side. The hole 13 is provided for stringing the face portion 1. The hole 13 is provided in the groove 12 at a portion other than the side portion 11 of the face portion 1.

  FIG. 5 is a diagram showing details of the structure around the side portion 11 in the racket frame according to the first embodiment. As shown in FIG. 5, a bumper 14 is preferably provided on the outer periphery 1 d side of the side portion 11. The bumper 14 is provided to protect the string passed through the hole 13.

  The bumper 14 has a bumper body 14a, a protrusion 14b, a bumper groove 14c, and a bumper hole 14d. The protrusion 14b is formed on the side attached to the side portion 11 of the bumper body 14a. The bumper 14 is attached to the side portion 11 by inserting the protrusion 14 b into the hole 13. A bumper groove 14c is formed on the side of the bumper body 14a opposite to the side on which the protrusion 14b is formed. A bumper hole 14d (see FIG. 7) is formed in the protrusion 14b. A string is passed through the bumper groove 14c and the bumper hole 14d. Thereby, the string is protected by the bumper 14. Preferably, the bumper 14 is a separate body from the face portion 1. The material used for the bumper 14 is nylon resin, for example.

  As shown in FIG. 1, the shaft portion 2 includes a first branch member 21 and a second branch member 22. The grip part 3 includes a grip member 31 and a grip 32. The first branch member 21 and the second branch member 22 are branched from the grip member 31. The grip 32 is formed so as to cover the grip member 31. For the grip 32, for example, polyurethane is used.

Below, the manufacturing method of the racket frame which concerns on 1st Embodiment is demonstrated.
First, a prepreg cutting step S1 is performed. A prepreg is a sheet-like material in which reinforcing fibers such as carbon fibers are impregnated with a thermosetting resin such as an epoxy resin. The prepreg is cut into a desired shape according to the shape of each member of the racket frame.

  Second, a prepreg winding step S2 is performed. The cut prepreg is wound around, for example, a nylon tube. The tube around which the prepreg is wound is inserted into a mold shaped like a racket frame.

  Third, a prepreg curing step S3 is performed. The mold in which the prepreg is inserted is heated to a predetermined temperature and held in that state for a predetermined time. Thereby, thermosetting resins, such as an epoxy resin in a prepreg, harden | cure. The cured prepreg is released from the mold. Thereafter, painting and attachment of the grip 32 are performed. As described above, the racket frame according to the first embodiment is manufactured.

  The effects of the racket frame according to the first embodiment will be described below. According to the racket frame according to the first embodiment, as will be described in detail below, the resilience performance and the spin performance can be improved. In addition, according to the racket frame according to the first embodiment, as described in detail below, it is possible to improve the feeling of holding the ball.

  FIG. 6 is a cross-sectional view of a surface perpendicular to the circumferential direction in the side portion 11 of the racket frame according to the comparative example. As shown in FIG. 6, the side part 11 of the racket frame according to the comparative example has a groove 12 on the outer periphery 1d side.

  On the other hand, in the racket frame according to the first embodiment, the face portion 1 does not have the groove 12 on the outer peripheral 1d side of the side portion 11. Therefore, the torsional rigidity in the side part 11 of the racket frame according to the first embodiment is higher than that of the comparative example.

  According to the knowledge found by the inventors of the present invention, the resilience performance and spin performance of the racket frame have a strong positive correlation with the torsional frequency of the racket frame. Further, according to the knowledge found by the inventors of the present invention, it is effective to increase the torsional rigidity of the side portion 11 in order to increase the torsional frequency of the racket frame.

  From the above, the racket frame according to the first embodiment can improve the resilience performance and the spin performance by adopting a configuration in which the groove 12 is not provided on the outer peripheral 1d side in the side portion 11 of the face portion 1.

  In the racket frame according to the comparative example, the groove 12 is provided on the outer periphery 1d side of the side portion 11 as described above. On the other hand, in the racket frame according to the first embodiment, the groove 12 is not provided on the outer periphery 1d side of the side portion 11.

  The length of the string is determined by the width of the face portion 1 and the depth of the groove 12. When the string is long, the deflection of the string when the ball is caught increases. Therefore, in the racket frame according to the first embodiment, the deflection of the string when the ball is caught is larger than that of the racket frame according to the comparative example. The hold feeling of the ball is improved as the deflection of the string when the ball is caught increases.

  From the above, the racket frame according to the first embodiment has a configuration in which the groove 12 is not provided on the outer periphery 1d side in the side part 11 of the face part 1, thereby providing a hold feeling when the racket frame catches the ball. Can be improved.

  FIG. 7 is a cross-sectional view of the racket frame according to the first embodiment in a state where the bumper 14 is attached to the side portion 11. As shown in FIG. 7, the bumper 14 has a bumper thickness TB. In the first embodiment, when the bumper 14 is provided, the string becomes longer by the bumper thickness TB. Therefore, with this configuration, it is possible to further improve the hold feeling when the racket frame catches the ball.

(Second Embodiment)
Hereinafter, the structure of the racket frame according to the second embodiment will be described first. Here, differences from the racket frame according to the first embodiment will be mainly described.

  Similar to the racket frame according to the first embodiment, the racket frame according to the second embodiment includes a face portion 1, a shaft portion 2, and a grip portion 3. Further, in the racket frame according to the second embodiment, the groove 12 is not provided on the outer peripheral 1d side of the side portion 11 as in the racket frame according to the first embodiment.

  FIG. 8 is a cross-sectional view of a cross section perpendicular to the circumferential direction in the side portion 11 of the racket frame according to the second embodiment. As shown in FIG. 8, the side part 11 has the FRP layer 11a. The FRP layer 11a includes a first FRP layer 11b and a second FRP layer 11c. Preferably, the FRP layer 11a has a third FRP layer 11d. Note that each of the first FRP layer 11b, the second FRP layer 11c, and the third FRP layer 11d may include a plurality of layers.

  The second FRP layer 11c is provided inside the first FRP layer 11b. The third FRP layer 11d is provided outside the first FRP layer 11b. The first FRP layer 11b is provided between the second FRP layer 11c and the third FRP layer 11d.

  The first FRP layer 11b is a CFRP containing the first carbon fiber 11e as a reinforcing fiber. The second FRP layer 11c is FRP containing the first reinforcing fiber. The first reinforcing fiber is preferably a second carbon fiber. However, the first reinforcing fiber is not limited to this. The first reinforcing fiber may be a reinforcing fiber having a Young's modulus lower than that of the first carbon fiber 11e. The third FRP layer 11d is an FRP containing second reinforcing fibers. The second reinforcing fiber is preferably a glass fiber. However, the second reinforcing fiber is not limited to this. The second reinforcing fiber may be a reinforcing fiber having a Young's modulus lower than that of the first carbon fiber 11e. Preferably, the second reinforcing fiber has a Young's modulus lower than that of the first reinforcing fiber.

  FIG. 9 is a diagram showing the internal structure of the first FRP layer 11b. As shown in FIG. 9, the 1st FRP layer 11b has the 1st carbon fiber 11e as a reinforcement fiber, and the thermosetting resin 11f. The thermosetting resin 11f is preferably an epoxy resin. The thermosetting resin 11f is filled between the first carbon fibers 11e.

  The Young's modulus of the first carbon fiber 11e is preferably higher than that of the second carbon fiber. The first carbon fiber 11e has a Young's modulus of 350 GPa or more and 1000 GPa or less, for example. Preferably, the first carbon fiber 11e has a Young's modulus of 500 GPa or more and 1000 GPa or less. In addition, the Young's modulus of the 1st carbon fiber 11e shall be measured based on ISO-11466.

  The first FRP layer 11b preferably has a plurality of layers. Preferably, the first FRP layer 11b has a first layer 11g and a second layer 11h. In the first layer 11g, the first carbon fibers 11e are arranged to be inclined with respect to the circumferential direction of the face portion 1 by the first inclination angle θ1. In the second layer 11h, the first carbon fibers 11e are arranged so as to be inclined with respect to the circumferential direction of the face portion 1 by the second inclination angle θ2 in the direction opposite to the first layer 11g. Preferably, the first layer 11g and the second layer 11h are alternately stacked in a direction from the inner side to the outer side of the side portion 11. That is, the first layer 11g and the second layer 11h are alternately stacked in a direction from the side where the second FRP layer 11c is provided toward the side where the third FRP layer 11d is provided. .

  The first inclination angle θ1 and the second inclination angle θ2 may be larger than 0 °. The first inclination angle θ1 and the second inclination angle θ2 are preferably 20 ° or more and 70 ° or less. More preferably, the first tilt angle θ1 and the second tilt angle θ2 are not less than 30 ° and not more than 60 °. The first inclination angle θ1 and the second inclination angle θ2 are particularly preferably 45 °. Preferably, the first inclination angle θ1 and the second inclination angle θ2 are equal.

  The fiber content ratio of the FRP layer 11a, that is, the mass ratio of the reinforcing fibers in the FRP layer 11a to the mass of the FRP layer 11a is preferably 45% or more and 80% or less. The mass ratio of the first carbon fibers 11e to the mass of the reinforcing fibers in the FRP layer 11a is preferably 3% or more and 50% or less. The fiber content ratio of the FRP layer 11a can be measured by removing the resin contained in the FRP layer 11a by combustion. That is, it can be calculated by dividing the mass of the FRP layer 11a before combustion by the mass of the FRP layer 11a after combustion.

  A cross section perpendicular to the circumferential direction of the side portion 11 has a radius of curvature R. The minimum value of the curvature radius R is preferably 3 mm or more. More preferably, the minimum value of the radius of curvature R is 5 mm or more.

Below, the manufacturing method of the racket frame which concerns on 2nd Embodiment is demonstrated.
First, a prepreg cutting step S4 is performed. The prepreg cutting step S4 is the same as the prepreg cutting step S1 in the first embodiment.

  Second, a prepreg winding step S5 is performed. The prepreg winding step S5 is basically the same as the prepreg winding step S2 in the first embodiment.

  However, the prepreg winding step S5 is different from the prepreg winding step S2 in the first embodiment in that the prepreg is wound around the portion corresponding to the side portion 11. In the prepreg winding step S <b> 5, first, a prepreg containing the first reinforcing fibers is wound around a portion corresponding to the side portion 11. Next, a prepreg containing the first carbon fiber 11 e is wound around a portion corresponding to the side portion 11. At this time, the first carbon fiber 11 e in the prepreg to be wound is wound so as to be inclined with respect to the circumferential direction of the face portion 1. Furthermore, a prepreg containing the second reinforcing fiber is wound around a portion corresponding to the side portion 11.

  Third, a prepreg curing step S6 is performed. The prepreg curing step S6 is the same as the prepreg curing step S3 in the first embodiment. As described above, the racket frame according to the second embodiment is manufactured.

  Hereinafter, effects of the racket frame according to the second embodiment will be described. According to the racket frame according to the second embodiment, the resilience performance and the spin performance can be further improved as described in detail below.

  The racket frame according to the comparative example has a groove 12 on the outer periphery 1 d side of the side portion 11. For this reason, in the portion where the groove 12 is provided, the member constituting the side portion 11 is sharply curved.

  The first carbon fiber 11e having a high Young's modulus is brittle and has poor deformability. When there is a place where the cross section of the member is sharply curved like the racket frame according to the comparative example, the first carbon fiber 11e having a high Young's modulus cannot be contained in the side portion 11. This is because the first carbon fiber 11e is broken at a sharply curved portion.

  On the other hand, the racket frame according to the second embodiment does not have the groove 12 on the outer periphery 1d side of the side portion 11. That is, the side part 11 of the racket frame according to the second embodiment does not have a sharply curved portion in its cross section. Therefore, the racket frame according to the second embodiment can use the first carbon fiber 11e having a high Young's modulus for the side portion 11.

  As described above, the racket frame according to the second embodiment does not have the groove 12 in the side portion 11, so that the torsional rigidity can be improved in terms of the material as well as the torsional rigidity in the shape. From the above, the racket frame according to the second embodiment can further improve the resilience performance and spin performance of the racket frame.

  In the racket frame according to the second embodiment, when the first carbon fibers 11e are arranged to be inclined with respect to the circumferential direction of the face portion 1, the torsional rigidity is further improved. Therefore, with this configuration, the resilience performance and spin performance of the racket frame can be further enhanced.

  In the racket frame according to the second embodiment, the side portion 11 includes a first layer 11g in which the first carbon fibers 11e are arranged at an inclination of the first inclination angle θ1 with respect to the circumferential direction, and the first layer 11g. Carbon fiber 11e has a second layer 11h arranged in a direction opposite to the first layer 11g with respect to the circumferential direction by a second inclination angle θ2, and the first layer 11g and the first layer When the two layers 11h are alternately laminated in the direction from the inside to the outside, the torsional rigidity is further improved.

  Therefore, with this configuration, the resilience performance and spin performance of the racket frame can be further enhanced.

  In the racket frame according to the second embodiment, when the minimum value of the curvature radius R in the cross section in the direction perpendicular to the circumferential direction of the side portion 11 is 3 mm or more, the first carbon fiber 11e having a high Young's modulus is not easily broken. . Therefore, with this configuration, the resilience performance and spin performance of the racket frame can be further enhanced.

  The first carbon fiber 11e has a high Young's modulus. Therefore, after the prepreg containing the first carbon fiber 11e is once wound, the wound prepreg may be peeled off. On the other hand, the second reinforcing fiber has a low Young's modulus. Therefore, such a peeling can be suppressed by further winding the prepreg containing the second reinforcing fiber on the prepreg containing the first carbon fiber 11e. That is, in the racket frame according to the second embodiment, when the side portion 11 has the third FRP layer 11d, the racket frame can be easily manufactured.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 1 Face part, 1a 1st front-end | tip, 1b 2nd front-end | tip, 1c inner periphery, 1d outer periphery, 11 side part, 11a FRP layer, 11b 1st FRP layer, 11c 2nd FRP layer, 11d 3rd FRP Layer, 11e first carbon fiber, 11f thermosetting resin, 11g first layer, 11h second layer, 12 groove, 13 hole, 14 bumper, 14a bumper body, 14b protrusion, 14c bumper groove, 14d bumper hole 2 shaft portion, 21 first branch member, 22 second branch member, 3 grip portion, 31 grip member, 32 grip, L distance, L1 distance, L2 distance, R curvature radius, S1 cutting step, S2 winding step , S3 curing step, S4 cutting step, S5 winding step, S6 curing step, T frame thickness, TB bumper thickness, Wmax maximum width, θ1 1 of the inclination angle, .theta.2 second inclination angle.

Claims (13)

A face part;
A grip part;
A shaft portion disposed between the face portion and the grip portion;
The face portion includes an outer periphery, an inner periphery, a first tip disposed on the shaft portion side, a second tip opposite to the first tip, the first tip, and a second And a side portion disposed between the tips of the
The said side part is a racket frame which does not have a groove | channel on the said outer peripheral side. The side portion has a position at a first distance from the first tip in the extending direction of the racket frame and a position at a second distance from the second tip in the extending direction of the racket frame. Between them,
The racket frame according to claim 1, wherein a value obtained by dividing the second distance by a third distance that is a distance between the first tip and the second tip is 0.25 or less.   The racket frame according to claim 2, wherein a value obtained by dividing the third distance by the first distance is 0.25 or less.   The racket frame according to claim 1, wherein the face portion has a bumper on the outer peripheral side of the side portion. The side portion includes a first carbon fiber,
The racket frame according to claim 1, wherein the Young's modulus of the first carbon fiber is 350 GPa or more and 1000 GPa or less.   The racket frame according to claim 5, wherein the Young's modulus of the first carbon fiber is 500 GPa or more and 1000 GPa or less. The side portion includes a first carbon fiber and a first reinforcing fiber,
The racket frame according to claim 1, wherein the first carbon fiber has a higher Young's modulus than the first reinforcing fiber. The side portion includes a second reinforcing fiber having a Young's modulus lower than that of the first carbon fiber,
The side portion includes a first FRP layer including the first carbon fiber, a second FRP layer including the first reinforcing fiber provided inside the first FRP, and the first FRP layer. The racket frame according to claim 7, further comprising a third FRP layer including the second reinforcing member provided outside the FRP layer.   The racket frame according to any one of claims 5 to 8, wherein the first carbon fiber is disposed to be inclined with respect to a circumferential direction of the side portion. The side part includes a first layer in which the first carbon fiber is disposed on the side part with a first inclination angle with respect to a circumferential direction, and the first carbon fiber is the side part. A second layer disposed at an inclination of a second inclination angle in a direction opposite to the first layer with respect to the circumferential direction of
The racket frame according to claim 9, wherein the first layer and the second layer are alternately stacked in a direction from the inside of the side portion toward the outside of the side portion.   The racket frame according to claim 10, wherein the first inclination angle and the second inclination angle are 20 ° or more and 70 ° or less.   The racket frame according to claim 11, wherein the first inclination angle and the second inclination angle are not less than 30 degrees and not more than 60 degrees.   The racket frame according to any one of claims 5 to 12, wherein a minimum value of a radius of curvature in a cross section perpendicular to the circumferential direction of the side portion is 3 mm or more.

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