Taking POM plastic materials as an example

selecting generalized Kelvin Model as visco-elasticity model for study plastic gear

the visco-elasticity deformation equation of plastic gear meshing with steel gear is obtained.Elastohydrodynamic lubrication equations are established with dimensionless method and following nonlinear equations are solved with discretization method to get the oil film shape and the pressure distribution with Newton-Raphson Iteration Method.The shape and thickness of oil film are both analyzed based on the plastic characteristics of visco-elasticity with the consideration of velocity and load.Results show that

the soft plastic gear being meshed with steel one is gradual film shape in the contact area being lubricated.Considering the visco-elasticity of plastics

the film shape becomes thicker in the main loading zone

the film gets thicker and the pressure peak moves towards entrance with increasing velocity.The film gets thinner and the pressure peak moves towards exit with the increasing load.