Failure mode analysis of automobile water pump bearings

[Virgo]

Automobile water pump is the key component of the engine cooling system. One end of the pump bearing inputs torque through the pulley, which drives the other end of the blade to rotate. In order to meet the development requirements of high power and high efficiency of the engine, higher performance requirements for pump bearings are put forward. Fracture, corrosion, peeling and grease leakage are common failure modes of automobile water pump bearings. Fracture is the most harmful. Therefore, it is necessary to analyze the failure modes of fracture and formulate corresponding preventive measures.
The chemical composition, hardness, metallographic structure and heat treatment process of the broken shaft were determined by inspection and analysis to meet the requirements of relevant technical specifications. However, the toughness of the bearing after quenching is insufficient, resulting in low flexural torsional fatigue strength. The load of the pulley is transmitted to the pump bearing through the flange, and the receding groove at the back of the flange has a notch effect at the tip, which is the stress concentration position and the crack source is easy to appear. Therefore, it is necessary to change the heat treatment process of the pump bearing and optimize the geometry of the pump shaft.