maximum published rating. A flooded spline would be indicative of a pump driven by a pump drive or
plugged into an auxiliary pad of a pump.
Maintaining a spline engagement at least equal to the Pitch Diameter will also maximize spline life. Spline
engagements of less than ¾ Pitch Diameter are subject to high contact stress and spline fretting.
Shaft torque for tapered shafts
The rated torque is based on the contact pressure between the shaft and hub surfaces with poor surface
contact areas. With an increased quality of the contact areas, the contact pressure between the shaft and
hub is increased and allows higher torque to be transmitted.
When a key is used for orientation of the hub on the shaft in conjunction with poor quality contact
surfaces, the transmitted torque will drop significantly. This is due to the key carrying the torque, which
limits the shaft torque carrying capability.
Maximum torque rating is based on an ideal contact area of 100 % and the retaining nut properly
torqued. This allows for the highest contact pressure between the shaft and the hub.
Shaft Availability and Torque Ratings
Alignment between the mating spline's pitch diameters is another critical feature in determining the
operating life of a splined drive connection. Plug-in, or rigid spline drive installations can impose severe
radial loads on the shafts. The radial load is a function of the transmitted torque and shaft eccentricity.
Increased spline clearance will not totally alleviate this condition; but, increased spline clearance will
prevent mechanical interference due to misalignment or radial eccentricity between the pitch diameters
of the mating splines. Spline life can be maximized if an intermediate coupling is introduced between the
bearing supported splined shafts.
For multiple pump installations, consider load of the entire pump stack. All torques are additive. Include
charge pumps loads when calculating torques.
Through torque diagram
Refer to the outline drawings for shaft dimensions.
Torque required by auxiliary pumps is additive. Ensure requirements don't exceed shaft torque ratings.
Shaft availability and maximum input torque - splined shafts
Option code Customer end Frame size/Maximum torque N•m [lbf•ft]
042 055 075 100 130 180 250
C3 15T 16/32 548 [404] n/a n/a n/a n/a n/a n/a
C6 21T 16/32 n/a 1287 [949] 1214 [895] 1214 [895] n/a n/a n/a
C7 23T 16/32 n/a n/a 1625 [1218] 1822 [1344] n/a n/a n/a
C8 27T 16/32 n/a n/a n/a n/a 2693 [1986] 3125 [2304] 3464 [2554]
Technical Information Series 90 Axial Piston Pumps
Features and Options
44 520L0603 • Rev 0804 • March 2016