Author(s)

Y. J. Chen & N. Huber

Abstract

Lobe pumps represent an intelligent design principle for fluid technology. They combine competence in design and complex high-precision manufacturing processes and find their application in the fields of automotive and mobile hydraulics industry. The chambers for inlet, movement and outlet of the fluid are formed in a continuous process by rotating gear-shaped parts, which are sealed by several sliding contacts. The ability to predict wear in such complex systems is essential for the development and lifetime prediction. Using a dynamic 2D finite element simulation, the transient contact pressure and slip conditions are obtained on the surfaces of the three parts of which the pump consists: inner rotor, outer rotor and housing. For the wear simulation it is necessary to handle simultaneous wear in multiple contacts and contacting surfaces. It is shown that it is possible to predict wear in such a system over a large number of rotations with considerable effect on the geometry of the different components. The simulations allow one to predict the number of rotations for a given wear coefficient until critical gaps are formed, which can significantly reduce the performance of the lobe pump. Furthermore, the wear profiles show that the wear between the outer rotor surface and the housing reflects the pressure difference in the pump as well as the symmetry of the rotors. This work shows that it is possible to predict wear and the changing kinematics of systems, which are based on moving contacts. Problems of future interest are gears, camshaft follower systems, or injection systems. Keywords: wear, wear prediction, transient contact, numerical simulation.

Keywords

wear, wear prediction, transient contact, numerical simulation