Frictional effects on the dynamic responses of gear systems and the diagnostics of tooth breakages

Abstract

To develop accurate diagnostic techniques, this study examines the dynamic responses of spur gear transmission system with including frictional effects on a tooth mesh process. An 8-degreeof-freedom model is developed to include the effects of supporting bearings, a driving motor and a loading system. Moreover, it takes into account not only the time-varying stiffness, but also the time-varying forces and moments due to the frictional effect. The latter causes additional vibration responses in the direction of the off-line-of-action (OLOA). To show the quantitative effect of the friction, vibration responses are simulated under different friction coefficients. It shows that an increase in friction coefficient value causes a nearly linear increase in the vibration features of diagnostics. However, features from torsional responses and the principal responses in the line-of-action show less changes in the vibration level, whereas the most significant increasing is in the OLOA direction. Furthermore, the spectral peaks at the rotational and sideband frequencies are influenced significantly by small breakage defects, especially when the friction effect is taken into account. In addition, the second and third harmonics of the mesh frequency are more influenced than the first harmonic component for all motions, which can be effective features for both indicating lubrication deterioration and improving conventional diagnostic features. ARTICLE HISTORY

Experimental and statistical analysis of wear on gear material

“…The presence of sulfation, oxidation, water and soot is determined by the presence of S O (1100-1200 cm À1 ), C O (1660-1800 cm À1 ), OH (3150-3800 cm À1 ) and (C C, C H) ($2000 cm À1 ) bond respectively that spreads over a defined range given in Table 2. 5,6,[23][24][25] Absorbance increases for sulfation, oxidation, water and soot as . Formation of OH compound refers to the presence of water molecules that has been reported to be responsible for increase in corrosion and decrease in viscosity.…”

“…Hence, the amount of sulphuric acid increases, and it causes decreases the TBN (total base number) and takes part in corrosion of the gear flank. [23][24][25] Peaks (absorbance) for sulfation, at wave no. 1200 cm À1 , oxidation at wave no.…”

“…50 N load and 1.2 m/s sliding speed are maintained during the measurement. Test temperature was maintained around 75 C. A graph for COF 25,29,30 with the running days of the machine is plotted in Figure 3 to understand the changes in tribological behaviour. COF is increasing with the running days of the machine.…”

Nonlinear dynamic analysis and defect detection of gears

“…The TVMS is considered as the most important source of excitation which depends on the time varying point of meshing during the line of action (LOA). Several research works have given a great interest in its study in healthy and cracked cases [12][13][14][15].…”

Helical gear wear monitoring: Modelling and experimental validation

“…Friction force variation has fluctuates considerably along the meshing line and as such it is a considerable source of helical gear system excitation [40,71]. To investigate more accurately the influence of gear lubricant parameters on dynamic response, a theoretical friction coefficient can be derived from elasto-hydrodynamic lubrication (EHL) and tribological theory [72] and in this study this was considered as the dominant mode of lubrication associated with the gear meshing surfaces.…”