Study on the Improvement of the Frictional and Mechanical Properties of Nylon 6 Containing Lubricants used in Electric Power Steering Reduction Gears 2005-01-1675

Recently, with advantages in weight, noise, and cost, plastic gears are fast replacing current metal gears, and gradually expanding their scope of application. Despite such advantages however, plastic gears have been limited in their application due to their relatively low performance levels in the areas of strength, abrasion, and friction. In general, the addition of lubricants significantly improves its frictional properties. Such improvements, however, are often accompanied by deteriorating mechanical properties,. Therefore, the amount of lubricant added needs to be properly controlled.

In this research project, we composed GF-reinforced nylon resins of various compositions, tested the resins for mechanical, frictional, and wear properties, and tested and analyzed the synergy between the lubricants. We conducted these experiments in order to determine the composition of lubricants that best improve the frictional properties of plastic, while minimizing the deterioration of the mechanical strength of nylon 6 - the material used for the reduction gear of the Electric Power Steering (EPS) system we are developing. We then produced reduction gears using the composed materials, and performed stand-alone tests with the gears on jigs. Finally, we performed critical durability tests with the gears on the EPS to evaluate their applicability.