THK HRW Series Wide-Rail Full-Ball LM Guide
The THK HRW Series is a full-ball LM Guide with a wide LM rail and a low overall height, giving it a low center of gravity. This makes it a good fit for use as a single rail in setups where space is limited, or where high rigidity against moment loads is needed.
Balls roll through four rows of precision-ground raceways on the LM rail and LM block. End plates inside the block let the balls circulate smoothly, while retainer plates keep them from falling off even if the rail is pulled out (except on the HRW 12 and 14LR models).
Each row of balls sits at a 45° contact angle, giving the HRW Series a four-way equal load structure. This means load ratings stay even across all four directions, radial, reverse-radial, and lateral, letting the guide be used in any orientation. The LM block can also take on a well-balanced preload, raising rigidity in all directions while keeping friction low and consistent. Because the LM rail is wide with a large cross-sectional moment of inertia, the HRW Series delivers high rigidity even as a single rail, without needing extra reinforcement like a side support.
The HRW Series also uses THK’s self-adjustment capability. A front-to-front arrangement of circular-arc grooves lets it absorb mounting errors even under preload, keeping motion accurate and smooth. There are 3 model variants, covering flanged and non-flanged types, with bolts mounted from above or from both above and below. Sizes range from 12 to 60. Basic dynamic load ratings run from 3.29 kN to 80.3 kN, and basic static load ratings run from 7.16 kN to 109 kN, depending on the model.
