| 摘要 |
PROBLEM TO BE SOLVED: To provide an excellent racket frame having the compatibility of flying capacity with vibration attenuation performance by forming the racket frame of a metallic core material and an outside layer made of a polyamide resin contg. a fiber reinforcing material and specifying the ratio at which this polyamide resin occupies the total weight of the racket frame to a prescribed ratio. SOLUTION: The racket frame 10 is formed of the metallic core material 11 and the outside layer 12 made of the polyamide resin contg. the fiber reinforcing material. The ratio at which the polyamide resin occupies the total weight of the racket frame is specified to 10 to 40wt.%. The metallic core material 11 having high specific rigidity and specific strength is preferable, for which aluminum, magnesium, titanium or their alloy are preferably used and more particularly the aluminum or aluminum alloy is adequately used. The weight ratio of the metallic core material 11 to the outer layer 12 made of the polyamide resin is set from the relation between the flat pressure rigidity and the vibration attenuation rate. The outer layer 12 of the polyamide resin is set at 10 to 40wt.% from the results of experiment in order to maintain the vibration attenuation rate within a range of 0.6 to 0.8%. |
