Dynamic modelling of a floating spline-coupling shaft system with parallel misalignment and tooth backlash

Floating splines are widely used in various shaft systems with high installation difficulty. The spline couplings’ stiffness characteristics significantly affect the shaft system dynamics. Most previous works have focused on ordinary spline-coupling shaft system dynamic modeling and ignored the effect of internal spline fillet-foundation deflection on the spline coupling stiffness. Thus, an improved stiffness calculation method of spline coupling considering internal spline fillet-foundation deflection is proposed in this work. The meshing force considering parallel misalignment and tooth backlash, and the parallel misalignment force are given. Then, the floating spline-coupling shaft system dynamic model with parallel misalignment and tooth backlash is established. An experiment is conducted to validate the accuracy of the proposed floating spline-coupling shaft system dynamic model. The results obtained from the proposed method and finite element (FE) models are compared. Moreover, the results obtained using the proposed method and other works are compared. Finally, the effects of parallel misalignment on the spline meshing force and spline coupling-shaft system dynamics are investigated. This work helps in accurate floating spline-coupling shaft system dynamic modeling and can provide guidance for diagnosing parallel misalignment error.