Air spring elliptical piston
A side load compensating air spring piston having an elliptical cross-section. The side load compensating air spring comprises an air spring sleeve forming a chamber and having a rolling lobe. One end of the sleeve is attached to a tilted end cap for side load compensation. The other end of the sleeve has a rolling lobe engaged with a piston elliptical outer surface. The piston elliptical outer surface is disposed at a 90° angle to an elliptical stress distribution in the sleeve, thereby rendering the stress distribution uniform in the sleeve rolling lobe portion as it rolls on the piston.
1. An air spring comprising:
a flexible sleeve having one end attached to an end member and the other end attached to a piston;
the end member is tilted at an angle θ with respect to a piston major axis A—A in the range of approximately 7° to approximately 20°;
the piston having an outer surface having only an elliptical cross-section;
the outer surface comprising a ratio between a major axis length and a minor axis length of approximately 1.08;
the flexible sleeve forming a rolling lobe cooperatively engaged with the outer surface; and
the flexible sleeve engaged with the piston outer surface such that the flexible sleeve comprises a substantially circular stress distribution.
2. The air spring as in claim 1 , wherein a major axis of a flexible sleeve stress distribution is disposed at approximately 90° to a major axis of the outer surface elliptical cross-section.