Experimental measurement of mesh stiffness by laser displacement sensor technique

Accurate measurement of mesh stiffness of a given gear pair is important for understanding the dynamics of gearboxes. Photoelasticity and strain gauge techniques are the only experimental techniques that are suggested to measure the mesh stiffness of cracked spur gear pairs in the literature. In the above two experimental techniques, the gear body deformation was not taken into account for the mesh stiffness measurement. In this work, a new experimental technique is designed to measure the mesh stiffness. For this, a well-established laser displacement sensor technique (LDST) is used. In this method spur gear tooth deflection is measured along the line of action by using the laser displacement sensor, consequently, gear mesh stiffness is calculated. The experiment is also performed on cracked tooth pair to measure the mesh stiffness. The main advantage of this experimental technique is to measure the total deflection of gear tooth with gear body deformation. The investigation shows that the gear mesh stiffness is reduced when crack size is increased. For validating the results of the experiment, FEA (finite element analysis) is performed to estimate the mesh stiffness. The mean mesh stiffness is measured as 0.76 × 104 N/mm by LDST and 0.96 × 104 N/mm by FEA for the healthy case. The results of the experiment are found having a good match with that obtained from FE method.