Overview

• For translating rotational motion to linear motion
• Threaded shaft provides a spiral raceway for balls which act as a precision screw
• Able to apply or withstand high thrust loads with minimum internal friction
• Made to close tolerances and therefore suitable for use in applications requiring high precision
• Ball assembly acts as the nut while the threaded shaft is the screw
• Common ball screw applications: Medical and laboratory equipment, straight line drives of numerical controlled machine tools, linear actuators for ordnance equipment such as missile and radar equipment, machine Tool table positioning drives and industrial applications requiring a high precision and an efficient linear drive mechanism The speed at which a ball-screw shaft can rotate and the load carrying capabilities are affected by the support bearings. Deep-groove ball bearings offer good radial stiffness but poor axial stiffness. Stiffness in both directions can be provided by using fixed supports with a steep angle contact ball bearing or pairs of angular contact bearings. The support bearings also need to provide the following important features:
• High axial load capacity and rigidity—Ball screw support bearings are required to carry large axial loads and minimize deflections for precise operation of the ball screw drive
• Compactness and light weight—Support bearings need to have thin sections to keep the size and weight of the surrounding design to a minimum and reduce torque requirements
• High Precision—Since most ball screws are used in applications requiring a high degree of accuracy, the support bearings also have to be able to provide a high degree of precision
• Pre-loaded adjustment—Axial or radial bearing clearance will have a negative influence on the rigidity of a ball screw system
• Low operating torque—For efficient ball screw operation, bearing operating torque and heat generation need to be kept to a minimum
• To meet these requirements, a high accuracy, steep angle, angular contact ball bearing is superior to combinations of standard angular contact bearings or arrangements of radial and thrust bearings for ball screw support applications