Ceramic ball bearing acoustic test method
AssigneeThe Aerospace Corporation
InventorsMichael J. O'Brien, Benjamin A. Nelson, Michael R. Hilton
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Abstract
An acoustical mechanical test method prescribes compressing brittle balls in spherical conforming opposing platens producing equatorial bulging, tensile stresses, and resulting in crack or flaw growth with emissions of acoustical sounds for direct identification of brittle balls having a flaw exceeding a maximum allowable size, such as flaws in silicon-nitride balls used in hybrid bearings as well as conventional steel ball bearings.
Claims12
A method for identifying a flaw exceeding a predetermined maximum allowable size in a ball having an equator, the equator defining north and south poles of the ball, the method comprising the steps of,
- applying an applied load in compression through opposing hemispherical surfaces having an arc length angle of less than ninety degrees, the opposing hemispherical surfaces conforming to the surfaces of the ball respectively at the north and south poles so that the ball bulges outwardly at the equator producing tensile stresses,
- determining a critical applied load when the flaw begins to grow and emit sound under the tensile stresses at the equator, and
- detecting acoustical emission at the applied load for identifying a flaw exceeding the predetermined maximum allowable flaw size.
Dependencies are inferred from the claim text.