Design of fluid film journal bearings containing continuous 3D fluid pathways which are formed by wrapping a sheet containing 2D through-cut features
Author(s)Winter, Amos Greene, 1979-
Massachusetts Institute of Technology. Dept. of Mechanical Engineering.
Martin L. Culpepper.
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The purpose of this research was to generate the knowledge required to: (1) design and manufacture fluid film bearings that do not require precision machining processes during fabrication, but rather gain their precision from off-the-shelf parts used in the fabrication process and (2) manufacture parts with 3D internal networks by wrapping thin sheets of material containing 2D through-cut features. This wrapping-based fabrication process, called Three-Dimensional Wrapped Network (3DWN) technology, uses the precision of low-cost, ubiquitous items instead of manufacturing processes to meet the precision requirements of hydrostatic bearings. 3DWN bearings are fabricated by cutting 2D through-cut features into shim stock and then wrapping the shim stock around a precision mandrel. The 2D shim stock features are designed such that they align and form 3D internal networks within the bearing during wrapping. In the final wrapped structure the bore retains the precision diameter of the mandrel and the surface finish of the shim stock, thus meeting the functional requirements of the bearing. This thesis investigates the design and manufacturing of 3DWN hydrostatic bearings.(cont.) An analytical model was derived to describe the transformation of 3D cylindrical features to 2D through-cut features. Conventional hydrostatic designs and theory were adapted for use in 3DWN bearings. A proof-of-concept was designed, constructed, and tested. Although contact between the shaft and bore was observed during testing, the fluid film stiffness matched theory within 1.6% after accounting for the contact stiffness. The mean bore diameter was measured to be within 0.03% of the mandrel diameter with errors that lie within 5[sigma] of the tolerable error range in the front of the bearing and 2[sigma] in the rear. In a comparison with a conventional hydrostatic bearing of the same size and surface design, the 3DWN cost lOX less.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Vita.Includes bibliographical references (leaves 110-112).
DepartmentMassachusetts Institute of Technology. Dept. of Mechanical Engineering.
Massachusetts Institute of Technology