| 摘要 |
<p>A lubricant cooling system for a sealed bearing section used in drilling with downhole motors comprises a radial bearing or bearings (38, 40) which preferably contain internal (56, 58) and external (46, 48) spiral grooves such that rotation of the central hollow shaft (10) which supports the drillbit forces lubricant (31) up the external grooves toward the upper seal (22) and then back down in the internal grooves along the cooled hollow shaft which has drilling mud flowing through it. Similarly, the rotation of the hollow shaft forces lubricant through an internal spiral in a lower radial bearing or bearings until it reaches the lower seal (30) at which time it is forced into the external spirals past the thrust bearings in the bearing section. This axial circulation effect allows the removal of heat efficiently from the lubricant by virtue of circulating drilling mud in the hollow shaft and in the outer annulus returning to the surface. The bearing section operating life is thus extended many hours because the lubricant attains a more uniform temperature throughout.</p> |
