A Novel Planetary Thread Roller Bearing: Design and Analysis of Load Characteristic

A novel planetary thread roller bearing (PTRB) was proposed in this paper based on the Hertz theory combined with multiple principles (e.g., equivalent steel ball, multi-point meshing, and power dividing). A significant improvement in load-carrying capacity, compared with existing bearings, was achieved and thus providing a new option for the advanced equipment with high thrust-To-weight ratio requirement. The newly proposed PTRB exhibited a 83% increase in dynamic axial load rating while a comparable static axial load rating comparing with the thrust ball bearing with a comparable size. Furthermore, the working efficiency of the new PTRB was constantly higher than 97%. A self-degradation operation was achieved by the system when some thread rollers were stuck, which improved the system fault tolerance. Finally, friction torque tests were performed on the self-developed test instrument. The results showed a good agreement with the theoretical analysis.