iLokTM Nut - An Innovative Fastener that Solves a 30 Year Old Problem for Rear Axle Hub Assemblies
Published April 2, 2019 by SAE International in United States
Annotation of this paper is available
Truck and bus manufacturers have been constantly facing an issue to disassemble the rear axle shaft from the hub when transporting the truck from the factory to the dealership. In addition to that, the dealerships have the very same problem every time they have to replace the brake pads in some truck models, which leads to excessive service time, extra costs and aftermarket complaints. The current problematic fastening system is composed by a lock nut, a flat washer and a coned slotted bushing. The concept of this 30 year old design involves the coned slotted bushing being pressed against a tapered hole on the shaft’s flange. After tightening the lock nut, the bushing clamps towards the stud and it gets stuck in between the shaft and the stud generating the problem described above. This paper shows the R&D process that Tekfor used to come up with the 1-piece fastener named iLokTM nut that replaces the problematic 3-piece fastening system. The methodology involved (a) Innovation process; (b) CAD modeling; (c) Finite Element Analysis; (d) Forging simulations; (e) Forging trials; (f) Prototypes manufacturing; (g) Torque and tension tests; (h) Junker vibration tests; (i) Proof load test; (j) Salt spray test; (k) Fit and function test, etc. The 1-piece fastener showed superior performance in all these tests and its usage brings multiple benefits to OEMs, Tiers 1 suppliers, Dealerships and end users. This is the most important innovation of a nut for the automotive industry since the advent of the wheel nut in 1972.