Accession Number:

ADA497481

Title:

A Low-wear Planar-contact Silicon Raceway for Microball Bearing Applications

Descriptive Note:

Final rept. Jan-Jul 2008

Corporate Author:

ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE

Personal Author(s):

• Waits, C. M.

Report Date:

2009-04-01

Pagination or Media Count:

34.0

Abstract:

As silicon rotary micro-electromechanical systems MEMS devices become critical components to power generation and sensor platforms, it is crucial to develop bearing mechanisms that can achieve speed and reliability requirements without increasing cost and complexity. Microball bearings have proven simple to fabricate and capable of achieving high speeds. However, previous microball raceway implementations showed substantial degradation in performance and required cleaning steps to improve reliability. Furthermore, large surface roughness on the raceway thrust surface caused increased wear and friction. In this work, the silicon raceway is modified by shifting the rotor bond interface, minimizing both wear and debris generation within the bearing. We developed a modified fabrication process that eliminates the source of the raceway thrust surface roughness. These modifications led to continuous and repeatable operation for over 4,500,000 revolutions with no degradation in performance. Our testing demonstrated speeds in excess of 85,000 rpm, more than twice that of previous designs.

Descriptors:

• *BALL BEARINGS
• *FABRICATION
• MICROELECTROMECHANICAL SYSTEMS
• TURBINES
• SILICON
• SURFACE ROUGHNESS
• WEAR

Subject Categories:

• Machinery and Tools

Distribution Statement:

APPROVED FOR PUBLIC RELEASE