Measurement Experiments and Theoretical Analyses of Mesh Stiffness of a Pair of Spur Gears

Mesh stiffness of a pair of gears is one of important factors to determine gear vibration. Since the mesh stiffness is affected by tooth profile modification, machining errors, assembly errors, shaft stiffness and key stiffness, it is difficult to measure the mesh stiffness of a pair of gears experimentally and analyze the mesh stiffness theoretically when the tooth profile modification and machining errors of the gears are considered. This paper proposes a new method and test rig to measure mesh stiffness of a pair of spur gears in the test rig experimentally. The mesh stiffness of the gears, stiffnesses of the gear shafts and keys are also analyzed using the simulation function of SolidWorks software. It is found that the measured stiffness of the pair of gears in the test rig is much lower than the calculated mesh stiffness of the pair of gears without considering the effects of the gear shafts and keys. It is also found that the measured stiffness becomes much closer to the calculated one if the stiffnesses of the gear shafts and keys are considered. This means that the actual stiffness of a pair of gears in a machine is also affected greatly by the stiffnesses of the gear shafts and keys. So, it is necessary to consider stiffnesses of gear shafts and keys in vibration analysis of a geared mechanical system.