| 摘要 |
<p>The present invention relates to a downhole driving unit for insertion into a well or borehole. The downhole driving unit comprises a driving section comprising a driving section housing and a plurality of wheel assemblies 3 coupled to the driving section housing and adapted to extend from the driving section housing to contact an inner wall of the well. Each of the wheel assemblies 3 comprises a motor housing 31 defined by a fixed stationary part 32 and a rotational part 342 configured for rotation, and an electrical motor 34 arranged in the motor housing 31 for driving the rotational part 342, wherein a section of the rotational part 342 constitutes a wheel 35 and the wheel assembly 3 comprises only one dynamic sealing 39 provided between the fixed stationary part 32 and the rotational part 36, the dynamic sealing 39 being configured for sealing the motor housing 31 to prevent ingress of well fluids.</p> |
