Numerical Study of the Pressure Distribution in Internal Gear Motor and Pump Considering with Misalignment of Ring Gear

The paper presents the calculation of 2D pressure distribution of lubricated oil film in the internal gear motors and pumps considering to misalignment of the ring gear by using the finite difference method (FDM). The equation of film thickness in case of misalignment is firstly established. The Reynold equation is then solved to obtain 2D pressure distribution. The results point out that the pressure distribution is greatly affected by the misaligned angle of the ring gear. If the ring gear is aligned then the pressure distribute evenly. However, if the ring gear is misaligned then the oil pressure distribution is not even. The maximum pressure will be transitioned to one side in axial direction of ring gear. Moreover, the misalignment causes the negative pressure area which leads to cavitation phenomenon and reduces the capacity of the oil film.