JP2003117027A - Racket frame and vibration-damping material mounted on racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the vibration-damping while inhibiting the increase of a weight of a racket frame. SOLUTION: A vibration-damping material 20 formed by integrating a cylindrical or solid rod-shaped vibrating part 21 and a basic part 22 projecting from one end of the rod-shaped vibrating part, is mounted on a head part 12 surrounding a hitting face of a racket frame 10 at a position free from the contact with a string S, the basic part 22 is fixed to the frame 10, the rod-shaped vibrating part 21 is projected from the head part, and the vibration-damping material 20 has dynamic viscoelastic loss coefficient tanδ of 0.30 or more and 1.50 or less when measured under a condition of frequency of 10 Hz and a temperature of -5 deg.C or more and 5 deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame and a vibration damping material attached to the racket frame. In particular, the racket frame suitable for hard tennis is designed to be lightweight and to have a high vibration damping property.

[0002]

2. Description of the Related Art A tennis racket frame is required to be light in weight so that it can be easily swung out even by a weak woman and seniors and has good operability. Therefore, a lightweight tennis racket having a weight of 280 g or less has recently appeared, and a weight reduction of 250 g or less is about to be achieved. However, as the racket becomes lighter, the impact on the racket frame at the time of hitting the ball increases, causing uncomfortable vibration, and the impact is easily transmitted to the elbow, which is a major cause of tennis elbow (so-called "tennis elbow"). Has become. Therefore, it is desired to reduce the vibration transmitted to the player by attenuating the vibration generated at the time of hitting the ball. That is, it is required to reduce the weight of the racket and improve the vibration damping property and the shock absorbing property at the same time.

Various types have been conventionally provided to improve the vibration damping property. For example, in JP-B-52-13455, JP-A-52-156031, and JP-A-4-263876, an elastic material is interposed in a tennis racket. The vibration suppression material consisting of a cantilever type damper that fixed the load material by
There is provided a vibration damping device that resonates with the vibration of the racket frame to damp the vibration. That is, in Japanese Examined Patent Publication No. 52-13455, as shown in FIG. 11 (A), at the end of the grip 5 of the tennis racket, from the elongated elastic member in which the base end of the steel wire 6b having the weight 6a attached to the tip is embedded in the frame. The cantilever type damper 6 is attached. In Japanese Patent Laid-Open No. 52-156031, FIG.
As shown in (B), the base portion 3a is fixed to the throat portion 4 of the tennis racket, the main body 3c is connected from the base portion 3a through the neck portion 3b, and the vibration absorbing material 3 that vibrates the main body 3c is attached. It is provided. In Japanese Patent Laid-Open No. 4-263876, as shown in FIG. 11 (C), the load member 4b is fixed to the grip end of the tennis racket via the elastic body 4a.

Each of the above-mentioned conventional rackets mainly contributes only to the damping of the primary vibration in the out-of-plane direction of the racket (the direction perpendicular to the ball striking face of the racket, the thickness direction of the racket frame), and the racket frame There is a problem that the weight increases because there is a weight that does not affect the physical properties of the main body.

Therefore, the applicant of the present invention has filed Japanese Patent Application Laid-Open No. 2000-15.
No. 7649, as shown in FIG.
The vibration damping material 1 including the viscoelastic body 1b and the head portion 2
It is installed in the out-of-plane direction and the in-plane direction, and contributes to the damping of each vibration mode. Furthermore, JP 20
In No. 01-37916, as shown in FIG. 13, a vibration damping material 8 is attached to a part of the string hole 7 of the racket frame 1 ′, and the string is inserted through the vibration damping material 8 when the string is stretched. Proposes that both the vibration of the string and the frame is attenuated.

[0006]

However, as shown in FIG.
In the configuration, when the string is stretched, the vibration damping material comes into contact with the string, and the vibration of the vibration damping material itself is regulated. Therefore, although it contributes to the vibration damping of the string, it does not contribute much to the vibration damping of the frame. found. Also in the case of the configuration of FIG. 13, similarly to FIG. 12, when the string is stretched, the vibration of the vibration damping material itself is regulated, and mainly contributes to the vibration damping of the string, but is not sufficient for the vibration damping of the frame itself. It has been found.

The present invention has been made in view of the above problems, and suppresses the weight increase of the racket frame as much as possible,
It is an object of the present invention to provide a racket frame in which vibration damping of the frame itself can be sufficiently achieved, and moreover, a vibration damping material capable of coping with various vibration modes of the frame is mounted.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a vibration integrally including a cylindrical or solid rod-shaped vibrating portion and a base portion protruding from one end of the rod-shaped vibrating portion. A damping material is provided, and the vibration damping material is arranged at a position where it does not come into contact with the string in the head portion surrounding at least the ball striking face of the racket frame, the base portion is fixed to the frame, and the rod-shaped vibrating portion is projected from the head portion. Moreover, the vibration damping material has a dynamic viscoelastic loss coefficient tan measured at a frequency of 10 Hz and a temperature of −5 ° C. or higher and 5 ° C. or lower.
The racket frame is characterized by having δ of 0.30 or more and 1.50 or less.

As described above, since the vibration damping material is arranged at a position where it does not come into contact with the string, the vibration of the vibration damping material is not regulated by the string, and when the vibration of the frame is transmitted, it easily vibrates. The vibration damping property of itself can be improved. In addition, since the rod-shaped vibrating portion is provided on the vibration damping material and the rod-shaped vibrating portion is projected from the frame of the head portion, the rod-shaped vibrating portion can freely vibrate in the three-dimensional direction. Even if it is projected in the in-plane direction (width direction), it easily vibrates in the out-of-plane direction,
It is possible to contribute to the damping of the out-of-plane vibration that occurs when the ball is hit. In particular, if the rod-shaped vibrating portion has a hollow cylindrical shape, it is easy to vibrate. The vibration damping material may be attached to the throat portion.

Dynamic viscoelastic coefficient tan δ of the vibration damping material
The measurement conditions are as follows: frequency is 10 Hz and temperature is -5 ° C or more and 5 ° C.
The reason is as follows. That is, when hitting at the center of the ball striking surface of the racket, the vibration modes excited are the secondary vibration outside the frame and the vibration of the string. According to the knowledge of the present inventor, the natural frequency of this out-of-plane secondary vibration is 500 Hz to 600 Hz at room temperature (25 ° C.) in recent years when the weight of the racket frame has been reduced. On the other hand, the measurement condition of the dynamic viscoelastic loss coefficient tan δ measured under the condition that the frequency is 10 Hz and the temperature is −5 ° C. is that the temperature is 500 Hz to 600 Hz at room temperature according to the temperature-frequency conversion rule.
Hz, which is 2 out of the plane of the racket frame.
Matches the frequency of the next vibration. The vibration mode excited at the time of off-center impact is the out-of-frame primary vibration. With the lightweight frame these days, the frequency is 100Hz
The frequency is 200 Hz, which corresponds to the measurement condition that the frequency is 10 Hz and the temperature is 5 ° C. Therefore, the frequency is 1
The dynamic viscoelastic loss coefficient tan δ measured at 0 Hz and a temperature of −5 ° C. or higher and 5 ° C. or lower is the same as when measured under the condition of the frequency of the out-of-plane secondary vibration of the racket frame generated at room temperature. Will be equivalent. It should be noted that ideally, at normal temperature, ta is set under the condition of a frequency of 500 Hz to 600 Hz.
Although nδ should be measured, the frequency conversion rule is used because measurement under this condition is impossible.

The reason why the dynamic viscoelastic loss coefficient tan δ is set to 0.30 or more and 1.50 or less is that if it is less than 0.30 or greater than 1.50, it becomes difficult to match it with the frequency of the racket frame, and the vibration damping This is because the performance becomes insufficient. The dynamic viscoelastic loss coefficient tan
δ is preferably 0.35 or more and 1.2 or less, and more preferably 0.56 or more and 0.72 or less.

The vibration damping material has a Shore A hardness of 60 or more and 95 or less. The Shore A hardness is set within the range of 60 or more and 95 or less because it is difficult to match the vibration damping material with the frequency of the frame when the Shore A hardness is outside this range. In addition, 62 or more and 93 are preferable.
It is below, and more preferably 65 or more and 90 or less.

The vibration damping material is molded from rubber, an elastomer or a resin, preferably a rubber composition is cross-linked to have a shape having the rod-shaped vibrating portion and the base portion. Especially, for 100 parts by weight of butyl rubber,
Carbon black 50-60 parts by weight, polystyrene block and vinyl-polyisoprene block triblock copolymer 10-25 parts by weight, zinc oxide 10-2
It is preferable that the rubber composition containing 5 parts by weight is vulcanized and molded. Hybler HVS-3 (manufactured by Kuraray Co., Ltd.) is preferably used as the triblock copolymer. The amount of carbon black may be 100 parts by weight without adding the triblock copolymer.

A base portion of the vibration damping member protruding in a direction orthogonal to the rod-shaped vibrating portion is fixed to the inner surface or outer surface in the thickness direction of the frame with an adhesive, and the rod-shaped vibrating portion is projected in the width direction parallel to the striking surface. There is. Alternatively, the rod-shaped vibrating portion is fitted to the inner peripheral surface of the through hole formed in the head portion with at least a portion thereof in contact, and the ball striking surface side or the surface opposite to the ball striking surface side is hit. Project in the width direction parallel to
The base is locked and attached to the outer surface or inner surface of the frame in the thickness direction.

In the vibration damping material, the cylindrical rod-shaped vibrating portion is projected toward the ball striking face side, the base portion is fitted in the string groove, the outer surface of the base portion is covered with the grommet of the string protecting material, and the grommet is stretched. Alternatively, the base portion of the vibration damping material may be pressed and fixed via the grommet. As described above, it is not necessary to press and fix the base portion of the vibration damping material to the frame by the string via the string protective material, and to fix the vibration damping material to the frame portion with an adhesive or the like. In addition, since the string protection material is interposed, it does not come into direct contact with the string, the vibration of the vibration damping material is not regulated by the string, and it can be fixed to the frame without using an adhesive. And the arrangement can be easily changed.

The cylindrical portion and the solid rod-shaped vibrating portion may have a circular cross section or a rectangular cross section, but a cylinder is most preferable. Further, the diameter may be increased toward the tip end or may be decreased, without making the cross-sectional area constant. As described above, the vibration damping material is preferably provided with through holes on the inner and outer surfaces of the head portion in the thickness direction, and the rod-shaped vibrating portion is projected on the ball striking face side in the width direction, but is opposite to the ball striking face. You may make it project outside from the outer surface of. Since the width direction surface of the frame is often narrow and arcuate, it is difficult to fix the base portion to the thickness direction surface, and it is difficult to provide the through hole to project the rod-shaped vibrating portion in the out-of-plane direction. It is not excluded to project in the out-of-plane direction.

The vibration damping material is provided at a required position on the head portion.
The total weight of these vibration damping materials is 0.8 g or more and 4 g or less. The vibration damping material is 4
The reason why the number is more than 28 is less than 4 is that if less than 4, vibration damping performance becomes insufficient, and if more than 28, the weight of the entire racket frame is increased and operability is deteriorated. Preferably, it is 8 or more and 24 or less. Moreover, the total weight of the vibration damping material is 0.8 g or more and 4 g or more.
When the amount is less than 0.8 g, each vibration damping material is less likely to resonate, and the vibration damping performance is reduced. On the other hand, if the weight exceeds 4 g, the weight increases, which affects the balance of the entire racket, which increases the moment of inertia and lowers the operability. The amount is preferably 1.0 g or more and 3.6 g or less, and more preferably 1.6 g or more and 3.2 g or less.

Further, the length of the rod-shaped vibrating portion of each vibration damping member protruding from the head portion is set to 10 mm or more and 15 mm or less,
The maximum transverse length is 2 mm or less and 4 mm or less. The length is 10 mm or more and 15 mm or less is 10
If it is shorter than 15 mm, it becomes difficult to resonate, and if it exceeds 15 mm, not only does it vibrate too much to match the natural frequency of the racket frame, but also when the vibration damping material is installed so as to project inside the head, strings, etc. This is due to the generation of abnormal noise, such as vibration noise, by touching. Regarding the relationship with the vibration cycle, the vibration cycle decreases as the length increases, and the vibration cycle increases as the length decreases. From the relationship with this vibration cycle, if it is 10 mm or more and 15 mm or less, the vibration cycle of the out-of-plane vibration is Correspondingly, it becomes easier to resonate. The maximum transverse length (diameter in the case of a cylinder) of 2 mm or less and 4 mm or less is too soft when it is less than 2 mm,
On the other hand, if it exceeds 4 mm, it becomes too hard on the contrary, and in both cases, the vibration frequency does not match the vibration frequency of the racket frame.
The size of the base portion is larger than the through hole of the head portion, and may be any size that can be locked in the head portion.

The above-mentioned vibration damping material is attached to a position where the vibration width is large at the time of hitting the ball, and at the top position at at least 12 o'clock and / or at the position of 3 o'clock and 9 o'clock when the head part is viewed as a clock face. The position where the vibration width when hitting a ball is large is 12
In the range from the top of the hour (upper part) to 1 o'clock, 11 o'clock, the range of the frame side from 3 o'clock to the yoke, and 9 o'clock to the yoke. It is an area of 90 degrees on each of the left and right sides sandwiching the lowest end of the section. In the out-of-plane secondary vibration, a 30 degree area centered at 12:00 of the head portion, a maximum width position of the frame side of 30 degrees from 3 o'clock to 4 o'clock, and a time of 9 o'clock to 8 o'clock 30 o'clock.
The degree area and the throat section. In addition, it is not necessary to attach the vibration damping material to all the positions where the vibration width is large, and the vibration of the frame can be suppressed by selectively attaching the vibration damping material.

Further, the present invention is a vibration damping material attached to a head portion of a racket frame, the rod-shaped vibrating portion protruding from a position where the head portion does not come into contact with the string, and the rod-shaped vibrating portion in a direction orthogonal to one end of the rod-shaped vibrating portion. It is provided with a base portion that is protruded and attached to a frame, and is vulcanized and molded into a rubber composition in which at least carbon black is mixed with a rubber component, and the rod-shaped vibrating portion and the base portion are integrally molded, and the frequency is A dynamic viscoelastic loss coefficient tan δ measured at 10 Hz and a temperature of −5 ° C. or higher and 5 ° C. or lower is 0.3.
Provided is a vibration damping material to be attached to a racket frame, which is characterized by being 0 or more and 1.50 or less.

[0021]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that all of the embodiments are applied to the rigid tennis racket frame.

1 to 3 show a first embodiment. The racket frame 10 (hereinafter abbreviated as the frame 10) is made of a continuous pipe made of fiber reinforced resin.
0, head 12, throat 13, shaft 1
4. A grip part (not shown) is continuously formed, and both ends of the yoke 17 are connected to the throat parts 13 on both sides to surround the head part 12 and the ball striking face F. The weight of the frame 10 is reduced to 270 g to 250 g.

The head portion 12 of the racket frame 10
A plurality of vibration damping materials 20 are attached to the top portion 15 and the inner surfaces of the left and right side portions 16 in the thickness direction of the ball striking face.
The top portion 15 is an area of 30 degrees to the left and right centering on the top 12a of the head portion 12, and the side portion 16 is the maximum width position of the head portion 12 on the left and right sides (3 o'clock, 9 o'clock).
It indicates a region of 30 degrees downward from (time). As shown in FIG. 2, the string S is passed through the top portion 15 and the string hole 11.
A total of eight vibration damping members 20 are attached to each of four positions on both sides in the front-rear thickness direction (on both sides from the central portion where the string hole 11 is formed) sandwiching the striking face F that stretches. Also,
Similarly, on each of the left and right side parts 16, four vibration damping agents 20 are provided, four on each side in the front-back thickness direction sandwiching the ball striking face F.
Is attached.

As shown in FIG. 3, the vibration damping member 20 comprises a cylindrical rod-shaped vibrating portion 21 and a base portion 22 integrally formed at one end in the orthogonal direction. In this embodiment, a 4 mm square plate-shaped base portion 22 is projectingly provided at one end of a cylindrical rod-shaped vibrating portion 21 having an outer diameter of 3 mm and a height of 15 mm.

The vibration damping material 20 is made of butyl rubber 10.
A rubber composition containing 50 to 60 parts by weight of carbon black, 10 to 25 parts by weight of a triblock copolymer having a polystyrene block and a vinyl-polyisoprene block, and 10 to 25 parts by weight of zinc oxide based on 0 part by weight. It is vulcanized and molded.

The vibration damping material 20 has a frequency of 10 Hz.
At a temperature of −5 ° C. or higher and 5 ° C. or lower, the dynamic viscoelastic loss coefficient tan δ is 0.30 or more and 1.50 or less,
In this embodiment, it is set to 0.56. The Shore A hardness is 60 or more and 95 or less and is set to 74 in this embodiment. Further, the total weight of the vibration damping member 20 mounted on the head portion 12 is within the range of 0.8 g or more and 4 g or less, and is 3.2 g in the present embodiment.

As shown in FIG. 2, the vibration damping member 20 has a frame 10 so that the base portion 22 and the rod-shaped vibrating portion 21 do not touch the string S and other portions of the frame 10 even when the string S is stretched. The base 21 is fixed to the inner surface of the ball striking face side with an adhesive. A rod-shaped vibrating portion 21 that projects vertically from the base 22 is made to project in a direction substantially parallel to the ball striking face F and toward the ball striking face.

The frame 10 having the above-described structure is an out-of-plane 1
The vibration damping material 2 mounted on the top portion 15 having a large vibration width of the secondary vibration and the side portion 16 having a large vibration width of the out-of-plane secondary vibration.
The rod-shaped vibrating portion 22 of 0 resonates with the vibration of the frame 10 when the ball is hit. Due to the resonance of the vibration damping material 20, both the out-of-plane primary vibration and the out-of-plane secondary vibration of the frame 10 are damped, and the impact transmitted to the player's elbow at the time of hitting the ball can be alleviated.

Particularly, since the dynamic viscoelastic loss coefficient tan δ of the vibration damping member 20 is set to 0.56 and the Shore A hardness is set to 74, the rod-shaped vibrating portion 22 easily matches the frequency of the frame 10, and , The vibration damping material 20 is the string 2
Since the rod-shaped vibrating portion 22 is arranged so as not to come into contact with 0 or other portions of the frame 10, the vibration damping effect can be sufficiently exhibited without restricting the resonance of the rod-shaped vibrating portion 22. Furthermore, since the total weight of the vibration damping member 20 is suppressed to 3.2 g, it is possible to achieve both weight reduction and vibration suppression of the racket frame without hindering weight reduction of the racket.

FIG. 4 shows a main part of the second embodiment of the present invention. Unlike the first embodiment, the bar-shaped vibrating portion 21 of the vibration damping material 20 is arranged so as to project on the outer surface of the thickness direction surface of the head portion 12 and on both sides of the string groove 18 in the front-back thickness direction, The base 22 is fixed to the frame 10 with an adhesive. The bar-shaped vibrating portion 21 of the vibration damping material 20 and the head portion 1
Also in the present embodiment in which the outer surface of the thickness direction surface of No. 2 is projected in the width direction, the rod-shaped vibrating portion 21 can sufficiently resonate without touching the string S or other portions of the frame 10, so that the racket frame Vibration can be suppressed.

In the first and second embodiments, the vibration absorbing member 20 is provided with a base portion on one rod-shaped vibrating portion, and the base portions are adhered and fixed to the frame, but FIGS. 5 (A) (B) (C). The configuration shown in FIG. In (A), the rod-shaped vibrating portion 21 has a solid round bar shape. In (B), the rod-shaped vibrating portion 22 has a cylindrical shape whose diameter increases toward the protruding end side. In (C), a plurality of rod-shaped vibrating portions 21 are juxtaposed and project from a common strip-shaped base portion 22, and the strip-shaped base portion 22 is fixed to the frame with an adhesive material.

6 to 8 show a third embodiment of the present invention. The vibration damping material 2 is provided only on the side portion 16 of the head portion 12.
0'is attached. In the frame 10 of the head portion 12 to which the vibration damping material 20 'is attached, through holes 31 are formed in the inner and outer walls 10a and 10b in the thickness direction between the adjacent string holes 30. Through hole 31 of outer wall 10b
Is a string groove (gut groove) 1 recessed in the outer wall 10b.
8 is opened on the bottom surface.

The vibration damping material 2 is inserted into the through hole 31 from the outside.
The rod-shaped vibrating portion 21 ′ of 0 ′ is projected from the inner wall 10 a toward the ball striking face side, while the base portion 22 ′ is fitted in the string groove (gut groove) 18.

Each string hole 1 is provided in the string groove 32.
A grommet (string protective material) 35 made of a hard resin, which is composed of a tubular portion 35a fitted to 1 and a band portion 35b fitted to the string groove 18, is fitted. This grommet 35
The belt portion 35b is brought into contact with the outer surface of the base portion 22 'of the vibration damping material 20'. Therefore, the tubular portion 35a of the grommet 35
The string S is passed through, the string S is passed along the outer surface of the band portion 35b and then passed through the adjacent tubular portion 35a, and the string S is stretched. Then, the grommet 35 is attached to the string S. The base portion 2 of the vibration damping material 20 ′ is mediated by the tightening force of S through the grommet 35.
2'is fixed to the frame. That is, the vibration damping material 20 '
Unlike in the first and second embodiments, the frame is not fixed with an adhesive material.

As in the third embodiment, the frame 1
0 may be provided with a through hole, a vibration damping material may be fitted and attached thereto, and the rod-shaped vibrating portion may be projected outward from the outer wall. Further, in the first and second embodiments, the vibration damping material is attached to the top position and the side position of the head portion 12, and in the third embodiment, the vibration damping material is attached only to the side position, but only the top position is attached. It may be attached to the yoke. Furthermore, you may attach to a throat part.

[Examples] As shown in Table 1 below, Examples 1 to 8 and Comparative Example 1 in which the specifications of the location, number, weight, material, tan δ, Shore A hardness, etc. of the vibration damping material were different.
5 to 5, the damping ratios and operability of the out-of-plane primary vibration and the out-of-plane secondary vibration of the racket frame were measured, and the actual hit test was also performed. In addition, when mounting the vibration damping material at the side position of the head part, mount the same number on the left and right side parts,
The number of mounted vibration damping materials on the side portions in Table 1 represents the total number of vibration damping materials mounted on the left and right side portions.

[0037]

[Table 1]

Each of the racket frames of Examples 1 to 8 and Comparative Examples 1 to 5 was manufactured by the same manufacturing method as the conventional tennis racket. Carbon fiber was used as the reinforcing fiber and epoxy resin was used as the matrix resin. The prepreg impregnated with the prepreg was laminated to form a pipe-shaped layup, and the layup was heat-cured together with a yoke material in a mold to be molded. The racket frame has the same shape, length, and hit area, and the maximum thickness of the frame is 26 mm (the top position of the head portion has a thickness of 11.50 mm, and the maximum width position at 3 o'clock and 9 o'clock is 13.00 mm). The total length is 27.51 inches and the hit area is 104 square inches. The weight of the frame is 261 g to 266 g, which is a lightweight frame.

The vibration-damping material to be mounted has a rod-shaped vibrating portion having a cylindrical shape with an outer diameter of 3 mm, a wall thickness of 0.8 mm, and a height of 15 mm, and the base portion has a plate shape of 4 mm square and the material is as follows. Different. Examples 1-7, Comparative Examples 2-5
Is fixed to the inner surface of the frame on the ball striking face side with an adhesive. Example 8 corresponds to the third embodiment and is grommet-fastened by passing through a through hole provided in the frame.

The vibration damping material used in Examples 1 to 5 was butyl rubber (trade name "IIR268" manufactured by Japan Synthetic Rubber Co., Ltd.).
100 parts by weight, ISAF carbon black (trade name "DIA I" by Mitsubishi Chemical Co., Ltd.) 60 parts by weight, triblock copolymer having polystyrene block and vinyl-polypropylene block (trade name "HIBLER HV" by Kuraray Co., Ltd.
S-3 ") 20 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, sulfur 1 part by weight, vulcanization accelerator (trade name" NOXCELLER TET "by Ouchi Shinko Chemical Co., Ltd.) 1.5 parts by weight and Other vulcanization accelerators (trade name of "Ouchi Shinko Kagaku Co., Ltd.
Z ") 0.5 part by weight of a rubber composition product was crosslinked and molded. The vibration absorber used in Example 6 was molded in the same manner as in Example 1 except that Hybler HVS-3 was not blended and the blending amount of carbon black was 100 parts by weight.
The vibration absorbers used in Examples 7 and 8 were
It consists of a single Hibler HVS-3 and is injection molded.

In Comparative Example 1, no vibration damping material was provided, and no vibration damping material was attached to the racket frame. The vibration damping material used in Comparative Example 2 was nylon 12 (ATO
The product is molded under the trade name "RILSON BMN-P20" of the company. Comparative Example 3 is formed of fluorinated silicone. Comparative Example 4 is made of polyester polyurethane. Comparative Example 5 is the above Example 1
It is made of the same material as the above. Comparative Examples 2-5
Is the dynamic viscoelastic loss coefficient tan δ of the vibration damping material is 0.30
It is out of the range above 1.50.

[Measurement Method of Dynamic Viscoelastic Loss Coefficient] The dynamic viscoelastic loss coefficient of the vibration damping materials of Examples 1 to 7 and Comparative Examples 2 to 5 was measured by a viscoelasticity measuring device (Shimadzu). It was measured by a viscoelasticity spectrometer “DVA200 improved side” manufactured by Seisakusho. The measurement conditions are frequency 10H
z, the temperature rising rate was 2 ° C./min, the sample was pulled by a jig, the initial strain was 2 mm, and the displacement amplitude was plus or minus 12.5 μm. The test piece has a width of 4 mm, a thickness of 1.66 mm, and a length of 30.0 mm. Since both ends of the test piece are chucked by 5 mm, the length of the displaced portion of the test piece is 2 mm.
It becomes 0.0 mm.

[Vibration Measuring Method and Damping Factor Calculation Method]
A string is stretched around the racket with a tension of warp yarn 551b × weft yarn 481b, and as shown in FIG. 9 (A), the racket having the acceleration pickup 41 attached to a required position is hung with a string 42, and FIG. 9 (B). As shown in (C), a predetermined position P of the racket frame was vibrated by the impact hammer 43. The acceleration pickup 41 was fixed in a direction perpendicular to the ball striking face. FIG. 9 (B) shows the measurement state of the out-of-plane primary vibration, and FIG. 9 (B) shows the measurement state of the out-of-plane secondary vibration. Next, the input vibration f measured by the force pickup attached to the impact hammer 43 and the response vibration α measured by the acceleration pickup are fed to the amplifier 44A,
44B through a frequency analyzer 45 (a dynamic single analyzer HP35 manufactured by Hewlett-Packard Co.
62A).

The transfer function in the frequency domain obtained by the above analysis was obtained to obtain the frequency of the racket frame. The vibration damping ratio ζ was calculated by the following formula. Each measurement was performed 5 times, and the average value of the results is shown in the table.

Ζ = (1/2) × (Δω / ωn) T0 = Tn / √2

[Method of Measuring Moment of Inertia in Swing Direction] As shown in FIG. 10, the grip end of the racket R is gripped, the head portion 12 is directed downward, and the head portion 12 is directed downward to make a swing as shown in the drawing. Is measured
The moment of inertia Is [g
/ Cm ² ].

Is = M × g × h (Ts / 2 / π)² M: Racket weight g: gravity h: Distance from the center of rotation to the center of gravity

The Shore A hardness of the vibration damping material is JIS-K.
It measured according to -6253.

The actual hitting test is a questionnaire survey of players about vibration and shock. Specifically, 57 middle / advanced players (ten tennis calendar years or more and currently playing three days or more a week). Vibration and shock 5
Table 1 shows the average value of the results evaluated by the perfect score evaluation.

As shown in Table 1, Comparative Example 1 in which the vibration damping material is not mounted and the dynamic viscoelastic loss coefficient tan of the vibration damping material
Comparative Example 2 in which a vibration damping material having δ of less than 0.30 is attached
In No. 4, the vibration damping rate was generally low, and the scoring result of the actual hit test was also low. Therefore, it was confirmed that the racket equipped with the vibration damping material having a tan δ of 0.3 or more attenuates the shock transmitted to the player.

Further, even when the vibration damping material of Comparative Example 2 having a Shore A hardness of more than 95 and Comparative Example 3 having a Shore A hardness of 60 or less are compared with Example 2 which is almost the same under other conditions, the Shore A hardness is 6
It was confirmed that the vibration damping ratio and the actual hit evaluation were higher when the ratio was in the range of 0 or more and 95 or less.

Further, comparing Example 3 in which the total weight of the vibration damping material exceeds 4 g with Example 2 in which the total weight of the vibration damping material is almost the same under other conditions, but 4 g or less,
It was confirmed that the moment of inertia value was high in Example 3 and the operability was not good. Therefore, it was confirmed that it is preferable to keep the weight of the vibration damping material mounted on the racket frame to 4 g or less.

Regarding the contact and non-contact between the vibration damping material and the string, the non-contact Example 2 and the comparative example 5 were used.
Comparing with the above, it was confirmed that the vibration damping rate was obviously higher and the impact on the player was alleviated when the vibration damping material did not contact the string.

Furthermore, comparing the results of Example 1 and Example 4, it was confirmed that the damping effect can be sufficiently exhibited even if the vibration damping material is attached only to the top portion of the frame instead of the side portion of the frame. However, it has been confirmed that it is preferable to attach the vibration damping material to both the top portion and the side portion as in Example 5 in order to effectively suppress the impact.

[0055]

As is apparent from the above description, in the racket frame of the present invention, a vibration damping material having a dynamic viscoelastic loss coefficient tan δ of 0.3 or more and 1.50 or less at a portion of the racket frame where the vibration amplitude is large. Since it is attached so that it does not come into contact with other parts of the string or racket frame, the vibration damping material resonates sufficiently at the time of hitting, suppressing various vibration modes of the racket frame, and the impact transmitted to the elbow of the player is suppressed. Can be relaxed. In particular, by mounting the vibration damping material so as to project parallel to the ball striking face, vibration in the out-of-plane direction can be effectively damped.

Further, by setting the total weight of the vibration damping material mounted on the racket frame to 0.8 g or more and 4 g or less, it is possible to sufficiently resonate the vibration damping material while suppressing the weight increase of the racket frame as much as possible. Therefore, the vibration of the lightweight racket can be suppressed and the operability can be improved. Further, by vibrating the vibrating portion of the vibration damping material into a hollow cylindrical shape, the vibrating property of the vibrating portion can be enhanced.

Furthermore, by setting the Shore A hardness of the vibration damping material within the range of 60 or more and 95 or less, the vibration damping material easily matches the frequency of the racket frame,
The vibration damping function can be enhanced.

[Brief description of drawings]

FIG. 1 is a partial front view showing a state in which a string is stretched on a racket frame according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of the racket frame shown in FIG.

FIG. 3 is an enlarged perspective view of the vibration damping material shown in FIG.

FIG. 4 is an enlarged perspective view of a main part of a racket frame according to a second embodiment of the present invention.

5 (A), (B) and (C) are perspective views showing modified examples of the vibration damping material.

FIG. 6 is an exploded perspective view of a racket frame and a grommet of a string protecting material according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a state where a vibration damping material is attached to a side portion of the racket frame.

FIG. 8 is a cross-sectional view showing a procedure for attaching a vibration damping material to a racket frame.

9A, 9B and 9C are diagrams showing a vibration measuring method.

FIG. 10 is a diagram showing a method of measuring the moment of inertia.

11 (A), (B) and (C) are views showing a conventional tennis racket.

FIG. 12 is a diagram showing another conventional example.

FIG. 13 is a diagram showing another conventional example.

[Explanation of symbols]

10 racket frames 11 string holes 13 Throat 15 Top 16 Side part 17 York 31 through hole 20, 20 'Vibration damping material 21, 21 'bar-shaped vibrating part 22, 22 'base F ball striking surface S string

Claims (7)

[Claims] 1. A head portion surrounding at least a ball striking surface of a racket frame, wherein a vibration damping member integrally provided with a cylindrical or solid rod-shaped vibrating portion and a base portion protruding from one end of the rod-shaped vibrating portion is provided. In addition, the vibration damping material is arranged at a position where it does not contact the string, the base is fixed to the frame, the rod-shaped vibrating portion is projected from the head portion, and the vibration damping material has a frequency of 10 Hz and a temperature of 10 Hz. Dynamic viscoelastic loss coefficient ta measured under conditions of -5 ° C or higher and 5 ° C or lower
A racket frame having nδ of 0.30 or more and 1.50 or less. 2. The vibration damping material is made of rubber, elastomer, or resin, and has a base portion projecting in a direction orthogonal to one end of the rod-shaped vibrating portion, and the base portion of the vibration damping material is an inner surface or an outer surface in a thickness direction of a frame. The rod-shaped vibrating portion is projected in the width direction parallel to the ball striking surface by fixing it with an adhesive, or at least a part of the rod-shaped vibrating portion is applied to the inner peripheral surface of the through hole formed in the head portion. Fitting in contact with each other, projecting in the width direction parallel to the ball striking face from the ball striking face side or the surface opposite to the ball striking face side, and locking the base to the outer surface or inner surface of the thickness direction surface of the frame. The racket frame according to claim 1, wherein the vibration damping material is mounted at a top position of at least 12 o'clock or / and at a position of 3 o'clock and 9 o'clock when the head portion is viewed as a clock face. 3. The vibration damping material to be mounted on the racket frame is 4 or more and 28 or less, the total weight of these vibration damping materials is 0.8 g or more and 4 g or less, and the length of the rod-shaped vibrating portion protruding from the head portion. The length is 10 mm or more and 15 mm
The racket frame according to claim 1 or claim 2, wherein the maximum transverse length is 2 mm to 4 mm. 4. The vibration damping material has a Shore A hardness of 60.
Any one of claims 1 to 3, which is not less than 95 and not more than 95
Racket frame described in paragraph. 5. The vibration damping material is butyl rubber of 100.
50 to 60 parts by weight of carbon black with respect to parts by weight,
10 to 25 parts by weight of a triblock copolymer having a polystyrene block and a vinyl-polyisoprene block,
The racket frame according to any one of claims 1 to 4, which is formed by vulcanizing and molding a rubber composition containing 10 to 25 parts by weight of zinc oxide. 6. The vibration damping material comprises a cylindrical rod-shaped vibrating portion protruding toward a ball striking face side, a base portion fitted into a string groove, and an outer surface of the base portion covered with a grommet of a string protecting material. The racket frame according to claim 1, wherein the racket frame is tightened by a string to be stretched, and the base portion of the vibration damping material is pressed and fixed via a grommet. 7. A vibration damping material attached to a head portion of a racket frame, the rod-shaped vibrating portion protruding from a position where the head portion does not come into contact with a string, and the bar-shaped vibrating portion protruding from one end of the rod-shaped vibrating portion to be attached to the frame. A rubber composition in which at least carbon black is mixed with a rubber component is vulcanized and molded, and the rod-shaped vibrating part and the base are integrally molded, and the frequency is 10 Hz and the temperature is -5 ° C. A vibration damping material attached to a racket frame, characterized in that a dynamic viscoelastic loss coefficient tan δ measured under the condition of 5 ° C. or more is 0.30 or more and 1.50 or less.