Numerical Simulation of Stresses in Thin-rimmed Spur Gears with Keyway

B Brůžek,E Leidich

doi:10.14311/480

Abstract

This paper contains an investigation of the key on a stress distribution in a thin-rimmed spur gear. A stress analysis was carried out by means of the Finite Element Method (FEM). The 2D-FE analysis has helped to find the influence of turning the gearing towards the keyway on the stress in the loaded root of the tooth and in the keyway. 2D and 3D numerical analysis has been used to find mutual influence of every single notch (root of tooth and keyway), influence of thickness of the hub, length of the key and the form of loading. Verification has been carried out through experimental method.

Highlights

These days there is no generally accepted calculation for design of thin-rimmed asymmetric loaded hub with gearing which would take into account both – impact of the notch of root of the tooth and impact of the notch of the keyway
The first principal stress was evaluated in loaded area of the root of the tooth, that means between the tooth Z2 and the tooth Z3, and in the keyway
Since the first principal stress is in the root of the tooth bigger than in the keyway, the length of the key has no influence on a crack initiation for the hub with module 2 mm

Summary

Introduction

These days there is no generally accepted calculation for design of thin-rimmed asymmetric loaded hub with gearing which would take into account both – impact of the notch of root of the tooth and impact of the notch of the keyway. A designer prefers thicker wall of hub in the critical places, that means over dimensioning. There are still reserves in the hub with the keyway. Thin-rimmed hub with gearing is used in many driving machine sets as a pinion in transmission, couplers and as a part of the braking mechanisms. Shaft-key-hub system is used very often, because of simple assembly and disassembly. During the testing of toothed wheels it was discovered that in the area of keyway crack initiation frequently occurs (Fig. 1). The cause are the notch stresses produced in the root of the tooth and in the keyway

Dimension assignation of the hub with gearing

Double-sided torque distribution

One-sided torque distribution

Length of the key

Numerical investigated influences

10 Conclusion