Interference Fit on Involute Splines by the Use of a Helix Angle at the External Spline

Involute splines are widely used in the industry and in the automotive area. Some automotive driveline applications require involute splined couplings with an interference fit (zero backlash). Current methods of production of splines result in relative big dimensional and form deviations, which are increased when parts are heat treated. Grinding process of the spline’s teeth has a high cost and is not suitable for high volume production.

There are three methods to achieve an interference fit:

1. 1)
   Sorting parts with internal spline by using a tapered gage and producing the parts with external spline accordingly;
2. 2)
   Make the external spline with tapered teeth along the spline length;
3. 3)
   Make the external spline with a small helix angle (in the order of minutes of degree) along the spline length.

This paper will approach the helix angle method and the process to find the best helix angle value for the interference fit.