The LM linear bushing is a recirculating ball bearing built around a hardened outer cylinder. Rows of bearing balls run in precision-ground tracks and return through a resin or steel retainer, so the balls roll rather than slide along the shaft — giving linear motion with friction coefficients comparable to rotary bearings.
Clearance is a design choice, not a defect
Running clearance between balls and shaft exists to absorb thermal expansion, mounting error and shaft deflection. Precision frames with aligned housings can use reduced clearance for stiffness; long shafts, welded frames or hot environments need standard or increased clearance. A bushing that feels tight by hand is not necessarily better — under load and temperature, tight becomes seized.
Lubrication intervals come from travel, not time
Grease life in a linear bushing is consumed by distance traveled and contamination ingested, not calendar days. High-cycle axes need relubrication by traveled kilometers; slow, clean axes run for years on factory grease. Sealed UU types extend the interval by keeping both grease in and contamination out.
- Standard grease: general automation, room temperature
- Food-grade grease: food and medical equipment
- Low-dust grease: clean-room and optical equipment
- Relubrication: based on traveled distance and environment
YZXQ supplies LM bushings pre-greased with general-purpose lithium grease; specify your environment in the inquiry and we will match the lubricant and clearance class to the application.
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