Linear motion rolling guide unit made of resin

Abstract

There is provided a linear motion rolling guide unit mainly comprising a square pillar-shaped long track rail having rail side track grooves formed in the longitudinal direction on both side surfaces of the rail, a casing having an inverse U-shaped cross section mounted over the rail through a concave portion, a pair of side plates fixedly joined to both longitudinally end surfaces of the casing, and rolling ball return passages formed in parallel in correspondence to the casing side track grooves. An endless circulating passage for rolling elements is formed by coupling at the extreme ends, the casing side track grooves and the return passages extending in parallel thereto by opposingly arranged arc-shaped direction turning passages. The track rail, casing, and side plates are made of high performance engineering plastics. Cylindrical projections and/or arcuate bridge-shaped U-turn tracks are formed on both longitudinally end wall surfaces of the casing. Projection inserting holes and/or U-turn track receiving holes are formed on one of side surfaces of each of the side plates at the positions corresponding to the projections and/or the U-turn tracks of the casing to be jointed therewith. By inserting and fixing the projections of the casing into the holes of the side plates in a snap-fitting manner, the casing and the side plates are accurately and fixedly joined. Thus, the direction turning passages, return passages, and track surfaces are easily accurately positioned to form endless ball circulating passages within the unit. The unit can be easily cheaply manufactured with a light weight and can be used in the severe physical and chemical conditions.