A propshaft design that has been in use for over twenty years may be ready for retirement thanks to a new design that reduces vehicle weight and noise, improves ride-and-handling, and increases vehicle safety.
Dubbed Slip-in-Tube, the new Visteon propshaft is set to supercede the ‘split between centre’ (SBC) design. Slip-in-Tube can be manufactured from lightweight aluminium or steel. It features a pair of splined tubes plunging into one another, eliminating the need for the steel slip and forged stud yokes used in conventional slip-between-centre (SBC) propshafts.
And the unique, single-end propshaft vent of Slip-in-Tube helps avoid installation problems and hydraulic lock-up of the tightly fitted splined tubes.
‘Visteon’s Slip-in-Tube propshaft is in many ways superior to the conventional concept. This particular design helps simplify the manufacturing process and eliminates the unpredictable noise, vibration and harshness (NVH) sometimes associated with typical machined splined components. The aluminium version reduces weight by as much as 30%. The result is a smoother, quieter ride for vehicle occupants,’ says Mitch Glowacki, Visteon’s chassis operations, Design Engineer.
The manufacturing of the new design uses a computer numerically controlled (CNC) cold rolling spline process. This technique means that no material – neither the inner nor the outer tube – is machined away. The process allows the tubes to slide in and out of each other easily even under heavy torque. Additionally, the aluminium material is anodised, which brings a hardness that reduces friction and extends the life of the components while preventing wear and corrosion.
According to Visteon, much of the undesired NVH behaviour (like clunking when changing gear) often associated with machine-splined components has been eliminated. With the Visteon design, the spline area of contact is 100 times greater than traditional machine splines, so friction and stress are lower.
Through the elimination of components, an integrated design and a simplified manufacturing process, Slip-in-Tube may provide a weight reduction of up to 30% and a 10 to 15% increase in critical speed over conventional SBC propshafts.
Slip-in-Tube enhances crash energy management by providing a controlled telescope distance of up to eight inches at a relatively low load. This allows energy to be absorbed in the event of a sudden impact. Unlike conventional propshafts, which tend to buckle in crashes, Slip-in-Tube simply telescopes into itself.
Flexibility in its length of up to 75mm also allows one part to fit several vehicle lines while conventional propshafts must be exact to length.
Slip-in-Tube is currently slated for production on a 2003 vehicle.