Guide balls prevent cage creep
Cage creep, where the ball or roller cage creeps out of its original position in a linear bearing without recirculating balls, is a well-known problem
. It can lead to increased friction, reduced travel length and shortened life.
In our June 2006 edition, we described a solution based on crossed rollers. Schaeffler has taken the idea a stage further – and as well as crossed rollers on each side of the carriage, an option for their new KMWE units incorporates additional locating balls.
The cages have a ‘U’ cross section, and the rollers sit in the sides, while the locating balls are located at the point of intersection of the roller guidance slots. The rollers run in ‘V’ shaped grooves in the bases of the carriages and guideways and provide positive control of the cage positions. The company says that compared with positive control mechanisms based on toothed rack designs, their solutions occupy less space and offer a better price-performance ratios.
The guides are ready to fit, preloaded guidance systems for linear locating bearing supports with a limited stroke. The units support loads from all directions, except the direction of motion, and moments about all axes.
