| 摘要 |
A downhole motor and bearing assembly for high pressure operation has a tubular housing with an inlet and outlet for flow of drilling fluid. A stator is supported in the housing and a rotor is supported for rotary movement in the stator. An open tubular shaft is connected to the rotor for rotary movement in the housing. The bearing assembly has bearing members in the housing in fixed spaced relation for carrying downward and upward longitudinal thrust loads. Since the motor is designed for high pressure operation, conventional bearings tend to wear out rapidly. In this motor and bearing assembly, the pressure of drilling fluid passing through the motor is bled into the down hole side of the bearings where the pressure is applied against an upset on the bearings shaft having an exposed area on the lower side sufficient to produce an upward thrust partially or completely offsetting the downward thrust produced by the pressure drop across the drill bit. The pressure balanced bearing assembly is operable in combination with any motor operating on flow of fluid, including Moineau motors, turbodrills, etc.
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