Ball-return system increases load capacity

March 21, 2002
A new line of precision-ground ball screws from Steinmeyer Inc., Bedford, Mass., runs faster than ball screws with conventional tube-type ball-return systems.

The 3526 UltraSpeed Series has a ball-return mechanism consisting of two-piece steel deflectors that guide balls into a return channel that spans the entire nut length. The deflectors minimize friction, letting the balls travel 33% faster than those in tube-type return systems. Lower friction also means longer travel life, less wear, and low noise and vibration levels. The screws are available with nominal diameters from 16 to 63 mm and with lead-to-diameter ratios ranging from 0.5:1 to 1:1. The screw moves at up to 4,000 in./min, at accelerations of 2 gs or more. Users have the choice between two preload configurations, letting them double the load capacity without increasing the length of the nut. One uses smaller balls with two-point contact and pitch offset in a single nut. The other has oversized balls and double the number of load-carrying balls, giving it a higher load-carrying capacity. It works best with length-to-diameter ratios of 30 or less and has slightly greater friction. The configuration with smaller balls is best for longer screws

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