A stator for use in a positive displacement motor. The stator comprises arubbercompound including fiber reinforcement. The fiber reinforcement includes aplurality ofelongated fibers. The elongated fibers in the fiber reinforcement create agrain directiongenerally with the grain in the longitudinal direction of the stator tube andacross the grain in thetransverse direction. The rubber compound has at least a 10% lower tensileModulus across thegrain than with the grain. The fiber reinforcement includes a fiber loading ofgreater than about2.5 phr of elongate fibers, the elongate fibers have a 100% tensile Modulus ofgreater than about60 GPa, and the rubber compound has a 25% tensile Modulus of greater thanabout 400 psiagainst the grain and a 50% tensile Modulus of greater than 700 psi againstthe grain. In someembodiments, the rubber reinforcement also comprises a blend of fibrillatedfibers and short cutfibers.
展开▼
