GETTING ON TRACK with guide wheels

摘要

Linear guides find use in a variety of precision-motion applications, from machine tools to medical equipment. They come in two basic types: plain bearing and rolling element. Rolling-element types are further categorized as recirculating ball bearing and guide wheel. Recirculating types support loads with a continuous stream of bearing balls that move in and out of contact with a guide rail. The bearings are made to follow straight sections with radii at their ends. This causes balls to vibrate and make noise as they accelerate from the straight to curved sections. The use of polymer cages that separate balls lowers but does not eliminate ball-bearing noise in square-rail desips. Guide wheels, in contrast, react loads through wheels that run on triangular-profile rails. Guide wheels can lower noise levels by 20% compared with square-rails systems because the ball-bearing raceway path is a constant radius.