BORE HOLE TOOL ASSEMBLY, BEARING SYSTEM FOR USE IN SUCH A BORE HOLE TOOL ASSEMBLY, AND METHOD OF DESIGNING SUCH A BORE HOLE TOOL ASSEMBLY

摘要

Bore hole tool assembly (1) comprising a housing (2) and a mandrel (3) reaching along an axial direction into the housing and a bearing system for transferring an axial load between the housing and the mandrel and allowing rotation of the housing relative to and about the mandrel, wherein the bearing system comprises at least two bearing stages (8, 9) each arranged to transfer part of the axial load, whereby each bearing stage comprises bearing means (4, 6) and mitigation means (5, 7) for distributing the load substantially proportionally over the respective bearing stages.