On the Mechanical Friction Losses Occurring in Automotive Differential Gearboxes

Grégory Antoni

doi:10.1155/2014/523281

Abstract

In the automobile industry, the mechanical losses resulting from friction are largely responsible for various kinds of surface damage, such as the scuffing occurring in some mechanical assemblies. These scuffing processes seem to be due to a local loss of lubrication between certain mechanical elements of the same assembly, leading to a sharp increase in the friction, which can lead to a surface and volume damage in some of them, and even can cause, in the worst case, the whole destruction of the mechanical system if it has continued to operate. Predicting and checking the occurrence of this kind of undesirable phenomena, especially in some principal systems of the vehicle, represents nowadays, a crucial challenge in terms of automobile reliability and safety. This study focuses on the mechanical friction losses liable to occur in differential automobile gearboxes, which can lead in the long term to the scuffing of these mechanical systems. The friction losses involved were modeled, using a simple analytical approach, which is presented and discussed.

Highlights

The automobile industry has contributed significantly during the last few years to increasing the CO2 levels polluting the atmosphere, the introduction of a Carbon Tax has been inciting car manufacturers to reduce this pollution
The mechanical losses resulting from friction are largely responsible for various kinds of surface damage, such as the scuffing occurring in some mechanical assemblies
This study focuses on the mechanical friction losses liable to occur in differential automobile gearboxes, which can lead in the long term to the scuffing of these mechanical systems

Summary

Introduction

The automobile industry has contributed significantly during the last few years to increasing the CO2 levels polluting the atmosphere, the introduction of a Carbon Tax has been inciting car manufacturers to reduce this pollution. When the vehicle is moving straight ahead, the two planetary pinions rotate at the same speed (as does the axle shaft associated with each of the driven wheel) and the two satellite pinions are stationary relative to their axis; that is, the differential housing and these. Where Pi, Ci, and ωi (with i = (lw, rw, en)) are powers, torques, and angular velocities associated with the left wheel, right wheel, and engine, respectively Upon introducing both the primary and secondary gearbox shaft yields, the ratio between the power of the differential ring gear and that of the engine is equal to the product of these shaft yields; that is, ηpsηss. Where ηps and ηss denote the primary and secondary shaft yields, respectively, and Prg, Crg and ωrg are the power, torque and angular velocity associated with the differential ring gear (drive gear), respectively.

Mechanical Losses

Discussions

Sensitivity Analysis

Conclusion