THK SR Series Radial Type Full-Ball LM Guide
The THK SR Series is a full-ball LM Guide with a compact design and a low cross-sectional block height. Its ball contact structure is built for large radial loads, making it well suited for horizontal guide units. 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 a retainer plate keeps them in place so they won’t fall out even if the block is removed from the rail. This low block height gives the SR Series high rigidity along with stable, accurate linear motion.
Unlike THK’s 45° contact angle models, the SR Series uses a 90° contact angle. This gives it a longer service life under radial load, better accuracy since machining errors have less effect on running accuracy, and higher radial rigidity, since displacement under the same load is lower. Because of this, the SR Series is ideal for locations where the load is mostly radial, or where accurate motion is needed in the vertical and horizontal directions. If reverse-radial load, lateral load, or moment load is significant instead, THK’s HSR Series (45° four-way equal load) is the better fit.
There are 5 model variants, covering flanged and non-flanged types, standard and short block options, and bolts mounted from above or below. Sizes range from 15 to 150, with basic dynamic load ratings from 9.1 kN to 411 kN and basic static load ratings from 11.7 kN to 537 kN, depending on the model. A stainless steel version is also available, with the LM block, LM rail, and balls all made of stainless steel.
