Micro rotary ball bearing with integrated ball cage: Fabrication and characterization

This paper presents a rotary MEMS ball bearing with an integrated silicon ball cage. The device is a deep groove radial ball bearing consisting of steel balls encapsulated between two micromachined silicon wafers. The silicon ball cage is released from the bulk silicon substrate during fabrication. The objective was to show that a simple caged bearing design provides reliable motion at both high and low speeds. The running torque of two identical devices was measured for speeds ranging from 10 to 20,000 rpm. One of the devices was disassembled before failure to provide images of the wear experienced during testing.