Dynamic Loads on the Gears of Electric Traction Motors Passing over a Rail Joint

Abstract

The movements of a pair of wheels and axle with and without an electric traction motor passing over a rail joint are investigated. The track is assumed to be resiliently supported and two basic idealized types of joint are considered. In the case of there being a traction motor on the axle, the rotating mass of the armature is regarded as a separate mass resiliently connected to the unsprung masses of the wheels and motor body and the dynamic gear loads are calculated. It is shown that further approximation of actual conditions was possible by a combination of the basic types of rail joint. A concrete example is evaluated and it is seen that the tooth loads are greater with a limited amount of resilience than with an ideally rigid drive, the maximum occurring in the region of the inherent structural resilience of a normal ‘non-resilient’ gear drive. Gear-tooth separation due to dynamic actions is investigated and it is found that the gear loads normally attending such separation are not excessive.