摘要 |
A reversible gerotor pump and a drivetrain subassembly including the reversible pump, wherein the pump includes inner and outer rotors located within an eccentric ring and also includes a drag spring mechanism, such as a band spring, positioned around and frictionally engaged with a portion of the outer rotor. Frictional engagement between the outer pump rotor and the band spring permits the outer pump rotor to apply a rotational force to the eccentric ring when the outer rotor reverses direction, thereby ensuring positive rotation of the eccentric ring 180 DEG upon reversal of the pump. The spring may be a split-band spring having a free diameter which is smaller than the outer diameter of the outer rotor, and the eccentric ring preferably includes an ear projecting radially inwardly and positioned between the ends of the band spring. In this manner, rotation of the outer rotor and spring causes rotation of the eccentric ring through force applied on the eccentric ring at the ear. A stop pin is provided to limit rotation of the eccentric ring to 180 DEG in either direction and, once the ring is restrained from further rotation by the stop pin, the pressure of the spring end on the ear causes the spring's diameter to slightly increase, thereby reducing wear on the outer diameter of the outer rotor.
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