Rotary tool and fluid motor

摘要

A rotary tool driving an abrasive member about a rotational axis is disclosed. The tool includes a fluid motor comprising an inner stator assembly having a longitudinal stator body and trunnions extending generally axially endwise from the stator body, the trunnions being eccentrically offset from the central longitudinal axis of the stator body. One of the trunnions having an inlet passage and the other an outlet passage. Bearings are carried by the trunnions and a rotor assembly is journaled on the bearings and is rotatable about the inner stator assembly. The outer rotor assembly includes a rotor body having a generally cylindrical bore therein for reception of the eccentric stator body when the stator assembly is journaled on the bearings concentric with the trunnions. The cylindric bore and the eccentric rotor body define an eccentric space therebetween. The stator body has at least one inlet opening therein for providing communication between the inlet passage and the outer surface of the stator body and at least one exhaust opening therein providing communication between the outer surface of the stator body and the outlet passage. The inlet and outlet ports are angularly offset with respect to one another on the stator body whereby upon holding the stator assembly against rotation and upon introducing pressurized air into the inlet passage, the pressurized fluid flows out of the inlet openings into the eccentric space thereby to forceably, rotatably drive the rotor assembly relative to the stator assembly. The abrasive member is carried on the outside of the outer stator body.