System and method to prevent premature wear on key shaft

A lubrication system for a key shaft of a compaction machine, the lubrication system comprising:

• a housing having an inner eccentric defining a bore therein;
• the key shaft positioned within the bore of the inner eccentric and reciprocating axially therein, the key shaft having a longitudinal lubricating passage extending through a remaining length of the key shaft and a plurality of additional lubricating passages intersecting the longitudinal lubricating passage;
• and
• a spline oil cavity positioned within the housing in fluid communication with the key shaft, wherein the reciprocating axial motion of the key shaft causes a pressure differential between the key shaft and the spline oil cavity during axial motion of the key shaft so that the key shaft pumps oil via the longitudinal lubricating passage.

A method of lubricating a key shaft of a compaction machine, the method comprising:

• providing an inner eccentric defining a bore therein;
• positioning a key shaft partially within the bore, the key shaft having a first outer portion with a helical spline, a second outer portion with a straight spline, and a longitudinal lubricating passage extending through a length of the key shaft in fluid communication with a plurality of lubricating passages intersecting the longitudinal lubricating passage;
• providing a spline oil cavity in fluid communication with the bore via the longitudinal lubricating passage and the plurality of lubricating passages of the key shaft;
• reciprocating the key shaft longitudinally with the bore to cause a pressure differential of oil between the key shaft and the spline oil cavity;
• and
• responsive to the pressure differential, lubricating the helical spline and the straight spline of the key shaft.