Design Optimization & Accelerated Testing of Power Steering Pump to Reduce Warranty Costs 2009-01-0557
Today’s automotive industry demands high quality component as well as system designs to be developed within very short period of time to provide more value added features to customers on one hand and to meet stringent safety standards on the other. To reconcile economy issues, design optimization has become a necessary & key issue to OEMs. In today’s automotive scenario, though Electric power steering system (EPS) is gaining importance, Hydraulic Power steering system (HPS) is still a common feature in almost all passenger cars in many of the developing countries, basically because of the cost and non-availability of advanced technologies. Power steering pump is heart of entire hydraulic power steering system. Failure of the pump and/or its related sub-assemblies is a threat to the safety of the entire vehicle and its occupants during various maneuvering events on the road.
Power steering pump is coupled to the vehicle engine with its drive derived from the engine. As the ground clearance of power steering pump on one of the vehicles is less, pump is prone to worst road conditions like continuous exposure to mud & slurry. Additionally, pump working on the principle of suction, mud & slurry accumulated at the suction adopter may get sucked in to the pump damaging the shaft seal and bearing. Also, due to bearing seizure, pulley connected to pump shaft was cracking as the drive to pump from engine is through pulley. Since the pump belt layout included Brake vacuum booster, breakage of the shaft/pulley was leading to depletion of vacuum to braking leading to very dangerous situation for vehicle control.
As a result, the position of the pump in the entire engine layout was to be modified. In view of packaging issues arising on other sub-systems, the position of pump on the vehicle could not be disturbed. All the above were forcing a situation to make the pump design robust to withstand this unusual & extreme conditions prevailing near the pump. Hence a methodology/procedure to simulate and compare the existing & modified designs was required to be developed and subsequently a design that can withstand the real world situations was to be evolved out.