This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Development of a Sprag Wear Test Procedure for Evaluating the Antiwear Performance of ATF's
Annotation ability available
Sector:
Language:
English
Abstract
A sprag clutch wear test procedure for evaluating the antiwear performance of automatic transmission fluids (ATF's) has been developed using a bench test apparatus. The wear test procedure provides an effective screening tool for incorporation into Automatic Transmission Service Fluid Qualification Test Procedures and Specifications. Two, widely-used ATF's provided reference data for wear comparisons and seven ATF candidates were evaluated for their antiwear performance. In addition, an additive-free, mineral-oil base stock was tested to highlight the need for fully-formulated fluids in automatic transmissions.
Surface texture analysis complemented the weight-change data which was used as the primary wear criterion. Supplemental tests which examined sprag components at various intervals throughout the test period provided sufficient data to suggest a possible mechanism for wear initiation and propagation in the sprag clutch.
Recommended Content
Citation
Caracciolo, F., "Development of a Sprag Wear Test Procedure for Evaluating the Antiwear Performance of ATF's," SAE Technical Paper 902149, 1990, https://doi.org/10.4271/902149.Also In
References
- Ferris E. A., “Automotive Sprag Clutches--Design and Application,” SAE Paper 208A, Presented at SAE Summer Meeting, June 5-10, 1960.
- “DEXRON®-II Automatic Transmission Fluid,” Specification GM 6137-M, 2nd Edition, July 1978.
- “MERCON® Automatic Transmission Fluid Specification - Service Fill,” Ford Engineering Material Specification No. WSP-M2C185-A, 1987.
- Hongo K., “Studies on the Popping of Sprags of Overrunning Clutches,” International Symposium on Gearing and Power Trans., pp. 431-436, Tokyo, 1981.
- Williams F. C., Tipping D., Henry T. A., “An Improved Sprag Clutch,” Institute of Mechanical Engineers, pp. 503-508, 1975.
- Williams F. C., Tipping D., Henry T. A., “The Dynamics of the Sprag Clutch,” Proceedings of Mechanisms 73, pp. 55-63, September 1973.
- Jorden W., “Gebrauchsdauer von Klemmfreilaufkupplungen (Operating Life of Overrunning Clutches),” Kunstuktion 24, Number 12, pp. 485-491, 1972.
- Haka, R. J., and Michnay, R. P., “Roller Skewing as a Factor in One-Way Clutch Operation,” SAE Paper 840576.
- Statgraphics Users Guide, Version 3.0, Part 2, Section 11.3, STSC, Inc. and Statistical Graphics Corp., 1986.
- Rollin A. J., European Patent Application EP 0 277 729 A1, “Lubricant Compositions Providing Wear Protection at Reduced Phosphorus Levels,” Amoco Corporation, January 21, 1988.