Metamorphic Flexure Bearings for Extended Range of Motion.

Abstract

Flexure bearings provide precise, low-maintenance operation but have a limited range of motion compared to conventional bearings. Here, we introduce a new class of bearing-the metamorphic flexure bearing-that not only retains the advantages of precision, low wear, and low hysteresis over its limited flexure-bearing range but also provides an extended range of motion as needed. This extended range of motion is achieved via a position-activated transition to a conventional sliding or rolling bearing. To demonstrate the operating principles of this new class of bearing, we describe, design, assemble, and test a linear-motion metamorphic flexure bearing using three categorically different transition mechanisms: a compression spring, a constant-force spring, and a pair of magnetic catches. This design paradigm has the potential to provide various benefits (e.g., reduced wear, reduced downtime, cost savings, and increased safety) in areas ranging from precision manufacturing to healthcare robotics to biomedical implants.