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Technique and Apparatus for the Measurement of Tube Bearing Friction

IP.com Disclosure Number: IPCOM000059973D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Hammer, R: AUTHOR [+3]

Abstract

A unique apparatus is designed to measure the friction (both static- friction (stiction), at start up, and running friction) of self- pressurized or externally pressurized tube bearings. Friction measurements can be made with a sensitivity of 240 mv/gm while the bearing is translated over extended distances greater than five inches. In the figure, the apparatus comprises a shaker table 1 consisting of an air-bearing-supported stage 2 driven by a linear motor (not shown) to translate the tube bearing 3 back-and-forth laterally in a sinusoidal fashion. Mounted to the shaker table is a force gage 9 which measures the force needed to translate the tube bearing. The force gage 9 consists of a spring 4 and fiber-optic displacement transducer 5. The spring is first calibrated so that its displacement versus force is known.

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Technique and Apparatus for the Measurement of Tube Bearing Friction

A unique apparatus is designed to measure the friction (both static- friction (stiction), at start up, and running friction) of self- pressurized or externally pressurized tube bearings. Friction measurements can be made with a sensitivity of 240 mv/gm while the bearing is translated over extended distances greater than five inches. In the figure, the apparatus comprises a shaker table 1 consisting of an air-bearing-supported stage 2 driven by a linear motor (not shown) to translate the tube bearing 3 back-and-forth laterally in a sinusoidal fashion. Mounted to the shaker table is a force gage 9 which measures the force needed to translate the tube bearing. The force gage 9 consists of a spring 4 and fiber-optic displacement transducer 5. The spring is first calibrated so that its displacement versus force is known. Spring displacement is measured by the use of a fiber-optic probe 5. More generally, any displacement transducer (e.g., capacitive, inductive, eddy current, or interferometer transducer) can be used in place of the fiber-optic probe 5. The force gage 9 is coupled to the tube bearing 3 by stictionless coupling 6. A steel ball 7 fastened to the bearing assembly 3 and a magnet 8 fastened to the spring comprise this coupling. In operation, the motion of the shaker table 1 is translated to the tube bearing through the spring
4. Displacement of the spring relative to the probe occurs when...