spline shaft

Splines are ridges or teeth[1][2][3] on a drive shaft that mesh with grooves in a mating piece and transfer planetary gearbox torque to it, maintaining the angular correspondence between them.

For instance, a equipment mounted on a shaft might use a man spline on the shaft that fits the female spline on the gear. The splines on the pictured drive shaft match with the feminine splines in the heart of the clutch plate, while the smooth suggestion of the axle is certainly supported in the pilot bearing in the flywheel. An alternative solution to splines is definitely a keyway and crucial, though splines give a longer fatigue life.[2]