Investigation into Improving Efficiency of Worm Gear with New Tooth Profile for EPS

Abstract

The authors have previously proposed a worm gear with a new tooth profile for use in electric power steering (EPS). Use of this new tooth profile enables a reduction in the diameter of the worm wheel.
This worm gear with its new tooth profile additionally provides increased transmission torque, reduced friction torque, and greater strength, thereby resolving basic issues that have previously affected conventional worm gears.
This paper describes the study of the worm wheel with the new tooth profile proposed by the authors that was conducted with a view toward enhancing transfer efficiency.
For this purpose, a meshing model for the worm gear was first created and used in order to examine the effects of the flexural rigidity of the worm wheel on transfer efficiency.
Next, worm wheels that actually have different flexural rigidity were fabricated. The transfer efficiency of the different worm wheels was studied in terms of their meshing area. The results revealed that there is a proper value for the flexural rigidity required to enhance transfer efficiency.