Abstract: Provided is an additive for imparting ultraviolet absorbency, or an additive for imparting a high refractive index, which has satisfactory compatibility with a resin serving as a matrix and can maintain high transparency even if added in high concentrations. Also provided is an additive with which the function of imparting both ultraviolet absorbency and a high refractive index can be realized by means of one kind of additive. This additive is represented by the following Formula (I): wherein at least one of R1a to R9a is a monovalent sulfur-containing group represented by the following Formula (i-1) or Formula (i-2): wherein R10a to R12a each represent a divalent hydrocarbon group or the like; and R13a represents a monovalent hydrocarbon group or the like.

Abstract: A screw device is provided which can facilitate management of a tolerance of a recess where a circulation component is housed. A circulation component is housed in a recess of a nut with clearance. At least part of the circulation component is blocked by a lid member fixed to the nut by fastening means. Upon a centrifugal force acting on a rolling element moving along a circulation path in the circulation component, the circulation component comes into contact at three points with the recess as viewed in an axial direction.

Abstract: A seal member for a ball screw device, which is fixed to an axial end surface of a nut member of the ball screw device and is configured to seal a gap between the nut member and the screw shaft, the seal member including: a plurality of base plates which each have a through hole having an inner diameter larger than an outer diameter of the screw shaft; a spacer plate, which is sandwiched between two base plates adjacent to each other, and has a seal accommodation hole having an inner diameter larger than an inner diameter of a through hole of the base plates; and a seal plate, which has a shaft-fitting hole corresponding to a sectional shape of the screw shaft in a direction perpendicular to an axial direction, and is arranged in the seal accommodation hole of the spacer plates.

Abstract: A seal member for a ball screw device, which is fixed to an axial end surface of a nut member of the ball screw device and is configured to seal a gap between the nut member and the screw shaft, the seal member including: a plurality of base plates which each have a through hole having an inner diameter larger than an outer diameter of the screw shaft; a spacer plate, which is sandwiched between two base plates adjacent to each other, and has a seal accommodation hole having an inner diameter larger than an inner diameter of a through hole of the base plates; and a seal plate, which has a shaft-fitting hole corresponding to a sectional shape of the screw shaft in a direction perpendicular to an axial direction, and is arranged in the seal accommodation hole of the spacer plates.

Abstract: A screw device is provided which can facilitate management of a tolerance of a recess where a circulation component is housed. A circulation component is housed in a recess of a nut with clearance. At least part of the circulation component is blocked by a lid member fixed to the nut by fastening means. Upon a centrifugal force acting on a rolling element moving along a circulation path in the circulation component, the circulation component comes into contact at three points with the recess as viewed in an axial direction.

Abstract: The rolling element screw device includes: a screw shaft having a rolling element raceway groove; a nut member, which has a loaded rolling element raceway groove opposed to the rolling element raceway groove and is threadingly engaged with the screw shaft through intermediation of the rolling elements; and the circulation component, which includes a pair of the first circulating portions passing through a peripheral wall of the nut member, and the second circulating portion coupling the pair of first circulating portions together, to thereby form the endless circulation path for the rolling elements. Each of the first circulating portions includes a first cylindrical portion fitted into a circulation component mounting hole of the nut member, and a second cylindrical portion which has an outer diameter larger than an outer diameter of the first cylindrical portion. The first cylindrical portion includes a rolling element introducing hole.

Abstract: The rolling element screw device includes: a screw shaft having a rolling element raceway groove; a nut member, which has a loaded rolling element raceway groove opposed to the rolling element raceway groove and is threadingly engaged with the screw shaft through intermediation of the rolling elements; and the circulation component, which includes a pair of the first circulating portions passing through a peripheral wall of the nut member, and the second circulating portion coupling the pair of first circulating portions together, to thereby form the endless circulation path for the rolling elements. Each of the first circulating portions includes a first cylindrical portion fitted into a circulation component mounting hole of the nut member, and a second cylindrical portion which has an outer diameter larger than an outer diameter of the first cylindrical portion. The first cylindrical portion includes a rolling element introducing hole.