Abstract: A slewing bearing assembly effective to suppress additional expenses such as a mold cost and to resolve the problem associated with insufficient strength brought about by voids and, also, a rotation section support apparatus for a wind powered turbine are provided. The slewing bearing assembly includes inner and outer rings having raceway grooves, and a plurality of balls interposed between the raceway grooves, and a spacer interposed between the neighboring balls. This slewing bearing assembly is a four point contact ball bearing, in which respective sectional shapes of the raceway grooves are so shaped as to represent shapes in which each balls contacts inner surfaces of the raceway grooves in the inner and outer rings at four points. The spacer is made of a resinous material having a melt viscosity within the range of 1000 to 2000 Pa·s at a temperature of 270° C.

Abstract: A slewing bearing assembly effective to suppress additional expenses such as a mold cost and to resolve the problem associated with insufficient strength brought about by voids and, also, a rotation section support apparatus for a wind powered turbine are provided. The slewing bearing assembly includes inner and outer rings having raceway grooves, and a plurality of balls interposed between the raceway grooves, and a spacer interposed between the neighboring balls. This slewing bearing assembly is a four point contact ball bearing, in which respective sectional shapes of the raceway grooves are so shaped as to represent shapes in which each balls contacts inner surfaces of the raceway grooves in the inner and outer rings at four points. The spacer is made of a resinous material having a melt viscosity within the range of 1000 to 2000 Pa·s at a temperature of 270° C.

Abstract: A swing bearing assembly includes a plurality of balls (3) interposed between double row raceway grooves (1a, 1b, 2a, 2b) in inner and outer rings (1, 2). The distance (ei) between the double row raceway grooves in the inner ring or the distance (eo) between the double row raceway grooves in the outer ring is within the range of a value equal to the diameter (Dw) of each of the balls to a value 1.7 times the diameter (Dw) and the diameter (Dw) of each of the balls is within the range of 30 to 80 mm, with the difference (?e) between the raceway groove distance (ei) and the raceway groove distance (eo) chosen to be within the range of 5 to 50 ?m. The double row raceway grooves are simultaneously processed with the use of alundum series grindstones.