Recirculation crossover insert and linear motion assembly therewith

A linear motion assembly, comprising:

• a ball nut having a through bore extending between opposite ends, said through bore having an internal helical groove;
• a screw having an external helical groove, said screw extending through said through bore of said ball nut with said external helical groove being radially aligned with said internal helical groove to define a plurality of ball raceways;
• a plurality of balls disposed in said ball raceways, said balls having a ball diameter;
• a plurality of crossover inserts fixed within said bore of said ball nut to recirculate said balls between adjacent turns of individual ball raceways, said crossover inserts each having a central body fixed within a recessed pocket of said ball nut and having a radially inwardly facing, generally s-shaped groove extending axially across said central body to route the balls between said adjacent turns, said crossover inserts further including a pair of legs extending outwardly from said central body in opposite directions from one another, wherein said legs are sized for a clearance fit with said external helical groove of the screw, said legs merging with the central body over a smooth transition region, wherein said transition region minimizes stress concentrations between said legs and said central body;
• and
• wherein said transition region includes a radii portion extending directly to said central body and a tapered portion extending from said radii portion away from said central body.