THK RSR Series Miniature Full-Ball LM Guide
The THK RSR Series is a full-ball LM Guide built with two rows of raceways instead of the usual four. Balls circulate through end plates in the LM block, which lets the guide achieve infinite straight motion. Because of this compact structure, the LM block delivers high rigidity in a small footprint, and combined with large-diameter balls, it holds up well in all directions.
Even as a single-rail guide, the RSR Series can take loads from any direction and still work well under a small moment load. The RSR-W model in particular has more effective balls and a wider LM rail, which improves rigidity against moment loads. This gives it a more compact, more durable setup compared to using a pair of parallel linear bushes. The LM rail, LM block, and balls are all made of stainless steel, giving the RSR Series strong corrosion resistance.
Since this series uses Gothic-arch grooves, precision on the mounting surface matters. If two RSR rails are used in parallel, any error in mounting surface accuracy can raise rolling resistance and affect smooth motion, so it’s important to follow THK’s flatness guidelines for the mounting surface. There are 4 model variants: RSR-M (standard), RSR-WM/WVM (wide block), RSR-N (long block), and RSR-WN (wide, long block), all with bolts mounted from above. Sizes range from 2 to 14. Basic dynamic load ratings run from 0.18 kN to 6.01 kN, and basic static load ratings run from 0.27 kN to 9.08 kN, depending on the model.
