Spline Shaft

A spline shaft is a cylindrical mechanical component featuring a series of longitudinal ridges (splines) that mesh with corresponding grooves in a mating part, such as a Pitman arm or rack assembly. In automotive steering systems, it transmits rotational torque from the steering gear to the steering linkage while permitting controlled axial movement to accommodate suspension travel and steering adjustments. The spline geometry ensures precise angular alignment and torque transmission without slippage.

The spline shaft operates on the principle of positive mechanical engagement, where the interlocking splines transfer rotational force (torque) between connected components. In recirculating-ball steering systems, it connects the Pitman arm to the steering gearbox output, converting rotary motion into linear motion for wheel turning. In rack-and-pinion systems, it may integrate with the rack to provide adjustable length or connection points. The spline design allows for slight axial sliding to compensate for dimensional changes during operation while maintaining torque transmission integrity.