Abstract: For the problem of fatigue failure in stator rubber bushing of PDM, which reduces motor efficiency and restricts the rate of penetration, a numerical model of PDM’s stator-rotor is established. The thermal coupling problem of rubber bushing working in a well is analyzed. The displacement, temperature and stress distribution of rubber bushing under different conditions and interferences are calculated. A new harmonic-distance rubber bushing was designed based on the structure of rubber bushing, and a finite element simulation on it is taken. The research indicates that the harmonic-distance rubber bushing not only has the advantage of equal-distance rubber bushing, but also has higher life of fatigue and anti-wear than the equal-distance rubber bushing; the displacement distribution is more uniform than the equal-distance rubber bushing; the new structure can guarantee the stability and efficiency of PDM stator and increase the rate of penetration.

Key words: rubber bushing, fatigue failure, one direction decoupling, finite element simulation