A rotating spline is one of a series of ridges on a driveshaft which mesh with and equalize the rotation speed of a mating piece, thereby transferring torque. For instance, a gear mounted on a shaft might use a male spline on the shaft that matches the female spline on the gear.
Manufacturers typically cut splines with a broach.
US Patent Issued to Zhongshan Broad-Ocean Motor on Oct. 4 for "Rotor for a Direct Current Drive Motor and a Method for Producing the Same" (Chinese Inventor)
Oct 10, 2011; ALEXANDRIA, Va., Oct. 10 -- United States Patent no. 8,030,808, issued on Oct. 4, was assigned to Zhongshan Broad-Ocean Motor Co....