Abstract: This present invention relates to a hollow golf club head comprising a face portion whose front face defines a club face for hitting a ball, wherein said face portion comprises a center portion forming an area having a sweet spot, and a peripheral portion surrounding the center portion and having the thickness smaller than the thickness of said center portion, wherein the thickness of the peripheral portion is reduced from the sole portion side of the head toward the crown portion side.

Abstract: A golf club head has a hollow shell structure comprising: a main frame provided with three independent openings which are a front opening, a top opening and a bottom opening; a face plate covering the front opening; a crown plate covering the top opening; and a sole plate covering the bottom opening. The specific gravity Gc of the crown plate, the specific gravity Gf of the face plate and the specific gravity Gs of the sole plate are each smaller than the specific gravity Gm of the main frame. Preferably, the specific gravity Gc is smaller than the specific gravity Gf and smaller than the specific gravity Gs, and the main frame is made of a metal material. Therefore, the freedom of designing the center of gravity the club head can be increased.

Abstract: A hollow golf club head comprises: a metal member made of at least one kind of metal material having at least one opening in a crown portion thereof; and a FRP member made of a fiber reinforced resin attached to the metal member so as to cover the opening, the fiber reinforced resin formed from a plurality of prepreg plies each having a magnitude covering the opening, and the prepreg plies comprising a plurality of unidirectional plies each having fibers aligned along an unidirection, wherein the unidirectional plies comprise at least “n” kinds of (in this case, “n” is an integral number not less than 3 and not more than 6) plies which are laminated in a state in which directions of the fibers are differentiated, and in a standard condition of being grounded on a horizontal plane at prescribed lie angle and loft angle, the directions of the fibers of the “n” kind of unidirectional plies seeing through a plane intersect at an angle (180/n) degrees obtained by substantially dividing 180 degrees by the integr

Abstract: A compound magnetic material having high heat resistance is provided. A fabrication method of a compound magnetic material includes the step of preparing mixed powder including an organic resin and compound magnetic particles. The long-period heat resistance temperature of the organic resin is at least 200° C. The containing ratio of the organic resin to the compound magnetic particles exceeds 0 mass % and not more than 0.2 mass %. The compound magnetic particle includes a metal magnetic particles, and a coat layer containing metal oxide, directly bound to the surface of the metal magnetic particle. The fabrication method of a compound magnetic material includes the steps of forming a compact by introducing mixed powder into a die having a lubricant applied to its surface and conducting warm-compacting, and applying heat treatment to the compact.

Abstract: A reference state is envisioned in which a golf club is placed on a horizontal plane P with a predetermined lie angle and face angle, and the shaft axis line thereof is disposed within a reference plane that is perpendicular to the horizontal plane P. A center of gravity of the head G is positioned on the back side of the head from the reference plane, and a depth of the center of gravity D that is a distance between the reference plane and the center of gravity of the head G is 20 mm or greater and 30 mm or less. The golf club has a flexural rigidity value EIt (kgf·mm2) of the shaft at a position T3 140 mm away from the tip on the head side being 0.5×106 or greater and 1.75×106 or less. More preferably, a value of a ratio (GIt/EIt) of the flexural rigidity value EIt to a torsional rigidity value GIt of the shaft at a position 140 mm away from the tip on the head side is specified to be 0.8×10?2 or greater and 1.2×10?2 or less.

Abstract: A wood-type golf club head has a volume V (cc) of not less than 350 cc and a club face area S (sq.cm) of not less than 30 sq.cm but not more than V×0.08+5. Preferably, the weight of the face portion is in a range of from 20 to 40% of the overall weight of the club head, and the overall weight is in a range of from 150 to 210 grams.

Abstract: A golf club comprises a club shaft having a tip end and a butt end, a club head being attached to the tip end of the club shaft, and a golf grip being attached to a region of the club shaft extending from the butt end toward the tip end of the club shaft, the grip having an end by the side of the butt end of the club shaft, wherein the club head has an moment (M) of inertia around a center line of the club shaft of not less than 6500 g·cm2, and the club shaft has a bending stiffness (E) of not less than 5.0×106 kgf·mm2 at the position which separates 200 mm from the end of the grip toward the club head.

Abstract: A wood golf club (10) which is not less than 44 inches in a length thereof and whose head (14) is not less than 190 g in a weight thereof. The value of a ratio of a rigidity value EIt at a position spaced at an interval of 130 mm from a head-side front end of a shaft (11) of the golf club (10) to a rigidity value EIb at a position spaced at an interval of 250 mm from a grip-side rear end of the shaft (11) is set to not less than 0.50.

Abstract: A golf club comprises a shaft and a head, wherein a moment Ix of inertia of the golf club head around a vertical axis passing through the center of gravity of the club head is not less than 3800 (g·sq.cm), and a shaft-torque T (degrees) of the golf club shaft and the moment Ix of inertia satisfy the following condition (1): T=<0.0025×Ix?6.0.

Abstract: A golf club shaft having a structure of a plurality of fiber reinforced prepregs layered one upon another. A grip-side reinforcing layer 6 (6A, 6B) and a head-side reinforcing layer 5 (5A, 5B, and 5C) are provided. In each of the grip-side reinforcing layer and the head-side reinforcing layer, a length of at least one of the prepregs is different from that of the other prepregs in an axial direction thereof, and the number of layers of the prepregs disposed at both ends of the golf club shaft is set larger than that of layers thereof disposed at a middle part of the golf club shaft.

Abstract: A hollow golf club head comprises: a metal member made of at least one kind of metal material having at least one opening in a crown portion thereof; and a FRP member made of a fiber reinforced resin attached to the metal member so as to cover the opening, the fiber reinforced resin formed from a plurality of prepreg plies each having a magnitude covering the opening, and the prepreg plies comprising a plurality of unidirectional plies each having fibers aligned along an unidirection, wherein the unidirectional plies comprise at least “n” kinds of (in this case, “n” is an integral number not less than 3 and not more than 6) plies which are laminated in a state in which directions of the fibers are differentiated, and in a standard condition of being grounded on a horizontal plane at prescribed lie angle and loft angle, the directions of the fibers of the “n” kind of unidirectional plies seeing through a plane intersect at an angle (180/n) degrees obtained by substantially dividing 180 degrees by the integral

Abstract: The invention prevents a crimple from being generated in a resin member. The invention provides a golf club head (1) including a head shell portion (M) made of a metal material and having an opening portion (O1), and a resin member (FR) made of a fiber reinforced resin arranged in the opening portion (O1), and provided with a hollow portion in an inner portion. The resin member (FR) is constituted by a molded body formed by integrally molding a laminated body of plural layers of prepregs having a magnitude covering the opening portion (O1) and having different resin percentage contents in the head shell portion in accordance with an internal pressure molding method. Further, the prepreg having the largest resin percentage content is used in an innermost layer of the laminated body closest to the hollow portion.

Abstract: A golf club shaft has an angular layer composed of prepregs in which a reinforcing fiber inclines to the axis of the golf club shaft; a plurality of straight layers composed of prepregs in which the reinforcing fiber is disposed substantially parallel with the axis of the golf club shaft. The reinforcing fiber of the prepreg at an inner side of the straight layer has an intermediate elasticity and a high strength. The tensile break strain of the prepreg at an outer side of the straight-layer is set higher than that of the prepreg at the inner side of the straight layer.

Abstract: An electric rotating machine includes a case, a stator, a rotor and an oil. The stator is comprised of a stator core and a coil. The oil has a volume resistivity ranging from 102 to 109 ?cm and is reserved in a bottom part of the case. The coil is partially immersed in the oil.

Abstract: This present invention relates to a hollow golf club head comprising a face portion whose front face defines a club face for hitting a ball, wherein said face portion comprises a center portion forming an area having a sweet spot, and a peripheral portion surrounding the center portion and having the thickness smaller than the thickness of said center portion, wherein the thickness of the peripheral portion is reduced from the sole portion side of the head toward the crown portion side.

Abstract: A golf club shaft composed of a laminate of prepregs obtained by impregnating reinforcing fibers with a resin, the weight (g) of the golf club shaft per unit length (mm) is less than 0.0385 g/mm. Prepregs, each including a reinforcing fiber having a high tensile modulus of elasticity not less than 300 GPa and a high tensile strength not less than 5000 MPa are disposed as a part of a straight layer in which the reinforcing fibers are parallel with the axial direction of the golf club shaft.

Abstract: A golf club shaft formed by winding prepregs of an angular layer and those of a straight layer around a mandrel (10) having a steeply tapered part (10B) formed at a tip side thereof and a gently tapered part (10C) formed, at a butt side thereof, continuously with the steeply tapered part (10B). Prepregs (17, 18) of the angular layer are disposed at the tip side of the mandrel (10). Butt-side ends (17a, 18a) of the prepregs (17, 18) of the angular reinforcing layer at the tip side of the mandrel (10) are disposed at the butt side of the mandrel (10) with respect to a boundary position (P2) disposed at a boundary between the steeply tapered part (10B) and the gently tapered part (10C). A distance from the butt-side ends (17a, 18a) of the prepregs (17, 18) of the angular reinforcing layer at the tip side of the mandrel (10) to the boundary position (P2) is not less than 5% nor more than 30% of a whole length of the shaft.

Abstract: The method of manufacturing soft magnetic articles comprises a step of preparing a melt solution containing soft magnetic materials and a step of forming soft magnetic particles from the melt solution in a magnetic field by an atomization rapid solidification method.

Abstract: A compound magnetic material having high heat resistance is provided. A fabrication method of a compound magnetic material includes the step of preparing mixed powder including an organic resin and compound magnetic particles. The long-period heat resistance temperature of the organic resin is at least 200° C. The containing ratio of the organic resin to the compound magnetic particles exceeds 0 mass % and not more than 0.2 mass %. The compound magnetic particle includes a metal magnetic particles, and a coat layer containing metal oxide, directly bound to the surface of the metal magnetic particle. The fabrication method of a compound magnetic material includes the steps of forming a compact by introducing mixed powder into a die having a lubricant applied to its surface and conducting warm-compacting, and applying heat treatment to the compact.

Abstract: In a golf club shaft composed of a laminate of prepregs obtained by impregnating reinforcing fibers with a resin, the weight (g) of the golf club shaft per unit length (mm) is less than 0.0385 g/mm. Prepregs each including a reinforcing fiber having a high tensile modulus of elasticity not less than 300 GPa and a high tensile strength not less than 5000 MPa are disposed as a part of a straight layer in which the reinforcing fibers are parallel with an axial direction of the golf club shaft.