DOWNHOLE MOTOR FOR A DRILLING APPARATUS

摘要

A drilling motor (20) comprises a stator (21) and a rotor (23) rotatably mounted in a stator (21). The stator (21) is provided with two opposed rod recesses (75) and two opposed exhaust ports (33). In use motive fluid is pumped through a central channel (27) in the rotor (23) and through a plurality of radially extending channels (58) into action chambers (31) between the rotor (23) and the stator (21). The rotor (23) has two opposed seals (76) which engage the stator (21) and the rod recesses (75) are each provided with rods (71) which, in use, also form a seal between the stator (21) and the rotor (23). The seals (76) and rods (71) can be made of a variety of materials including stainless steel. Two drilling motors (20, 50) can be arranged in parallel with their rotors out of phase to provide a relatively smooth power output and inhibit stalling.