Machine Design

Double planetary gears cut backlash in a big way

New PN planetary gearheads from Oriental Motor U.S.A. Corp., Torrance, Calif., cut backlash to less than 3 arc min compared to traditional planetary gears typically having backlash of 20 arc min.

The trick? Newly developed gears.

With the new design, both the internal and planetary gears have upper and lower stages. These "double planetary" gears consist of two pieces that apply pressure on the sun gear in opposite directions simultaneously, eliminating the gaps that produce backlash between gear teeth. The upper level internal and planetary gears reduce clockwise backlash while the lower level internal and planetary gears reduce counterclockwise backlash.

PN gearheads have six gear ratios ranging from 5:1 to 50:1, and can be used with the company's AlphaStep 2.36-in.2 and 3.54 in.2 motors.

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