1. HIWIN linear bearings enable high precision linear motion on round shafts by utilizing recirculating ball pathways.
2. The patented recirculation curve enables HIWIN’s linear bearing to sustain heavy loads with low noise and high stiffness.
3. HIWIN’s diverse line of linear bearings perform under almost any conditions and load capacities to satisfy a wide range of applications.
Linear bearing accuracy
Linear bearing accuracy is defined as the variation in height over the length of the travel. The best achievable accuracies for 120 in. rail length are +/- 0.0008 in. for round rail bearings and +/- 0.0001 in. for profile rails. In applications where running accuracy is critical, profile rail bearings typically can offer better accuracy than round rail bearings and metric round rail bearings offer better accuracy than inch round rail bearings. Super or ultra accuracy class profile rail bearings offer improved accuracy compared to standard profile rail bearings. Accuracy can also be improved by machining the mounting surface to a higher flatness tolerance and through the addition of a reference edge….
Shaft failure is common in short stroke applications where the stroke is less than 1.5 times the bearing length. Replacement of both the bearing and shafting may be required if metal fragments appear. Check the shaft for signs of wear such as spalling. Shaft grooving may sometimes be acceptable during the initial run-in if it is what is known as shakedown phenomena, and scratches are typically only cosmetic. Also, soft metal bearing housings, such as aluminum, can easily become indented at the bearing plate contacts. Indenting can interfere with bearing plate loading and self-aligning features so it may require the replacement of the housing.
Insufficient system repeatability problems are frequently caused by poor installation and set-up, excessive carriage deflection, or lack of stiffness. Stiffness can be improved by switching from round rail to profile rail or by switching from ball profile rail bearings to roller profile roller bearings. Repeatability can also be improved by reducing clearance in the bearing rail fitup. When profile rails are used, increasing preload will reduce deformation. When round rails are used, an oversize shaft and/or undersized housing bore can be specified to reduce clearance or provide a preload…