THK HR Series Separate Type Full-Ball LM Guide
The THK HR Series is a full-ball LM Guide with a separate rail design. When two rails are mounted in parallel on the same plane, the guide can take on equal load in all four directions, radial, reverse-radial, and lateral, since each row of balls contacts the raceway at a 45° angle. Balls roll through two rows of raceways, precision-ground on the LM rail and LM block. End plates inside the block let the balls circulate, while retainer plates keep them from falling off. Because of this low cross-sectional height, the HR Series achieves a compact, stable linear guide setup that’s also easier to adjust for clearance compared to cross-roller guides.
The HR Series also uses THK’s self-adjustment capability. Even if parallelism or level between the two rails isn’t perfectly set, a front-to-front arrangement of circular-arc grooves lets it absorb mounting errors and keep smooth straight motion, even under preload. Since this model uses end caps for ball recirculation, it avoids the cage or retainer creep issue that can happen with cross-roller guides. Its sectional shape is also similar to cross-roller guides, so components are dimensionally interchangeable with them.
There are two model types. Model HR is the heavy-load type, with sizes from 9 to 125 and basic dynamic load ratings from 2.82 kN to 226 kN. Model HR-T is the ultra-heavy load type, using a long block design, with sizes from 20 to 105 and basic dynamic load ratings from 20.8 kN to 153 kN. A stainless steel version is also available, with the LM block, LM rail, and balls all made of stainless steel.
