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Benefits of Profiling Tapered Roller Bearings - Matching Driveline Component Performance to the Demands of Higher Horsepower Engines of Heavy Duty Trucks
Technical Paper
1999-01-3767
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The heavy-duty trucking industry is continuing to move toward the use of higher horsepower engines. Engines exceeding 450 horsepower have become increasingly popular, with 500 - 600 horsepower engines expected to share a significant portion of the truck engine market in the next decade {Reference 1}. Sometimes these higher horsepower engines are used with existing gross combined vehicle weight, simply to increase the speed at which payloads are delivered. However, when higher engine horsepower is used to transport increased payloads, the result is higher loads and stresses on all driveline components between the engine and the wheels. All components downstream of the engine could be adversely affected.
The objectives of this paper are to:
- 1Alert truck axle and transmission manufacturers, as well as the trucking industry, of the potential effects of using higher horsepower engines in combination with increased payloads, with current/existing driveline components,
- 2Quantify the increase in internal contact stresses of tapered roller bearings used in typical truck drive line applications due to the combination of higher horsepower and increased gross combined vehicle weights,
- 3Describe the general methodology and factors considered in calculating these stresses, and
- 4Show that designing special internal profiles on tapered roller bearings can lower maximum contact stresses to acceptable levels.
In typical axle and transmission designs, high bearing contact stresses due to increased engine horsepower and payloads can be reduced, often to acceptable levels, using the same bearing envelope size, with special internal profiling. Consequently, redesign of shafts and housings to accommodate larger and heavier bearings may not be required. However, in some cases the stresses are so high that redesign can not be avoided. To illustrate these points, analyses of tapered roller bearings in typical tandem axles, single axles and transmissions will be used. The analyses show the maximum inner race roller-raceway contact stresses before and after profiling, as well as appropriate design and material limits. The loading for the examples is based on the Chicago to Portland (ChiPort) duty cycle, which is commonly used in application analysis.
The results presented in this paper have been generated analytically. Analytical tools developed by the Timken Corporation have accurately predicted satisfactory performance and acceptable stress values in existing applications. The same tools now predict higher stresses in these new applications having higher horsepower and increased payloads. This paper provides the means for communicating these concerns to the truck industry and serves as a reminder for driveline manufacturers to review loads and stresses if higher horsepower engines are being considered in conjunction with higher payloads.
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Citation
Fahrni, G. and Crichton, D., "Benefits of Profiling Tapered Roller Bearings - Matching Driveline Component Performance to the Demands of Higher Horsepower Engines of Heavy Duty Trucks," SAE Technical Paper 1999-01-3767, 1999, https://doi.org/10.4271/1999-01-3767.Also In
References
- Cross, Rich “Diesels on Steroids: 500-600 Horsepower… and Rising?” Commercial Carrier Journal 155 6 June 1998 50 54
- SAE Standard J-2188 “Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and Charting” March 1996
- Western Highway Institute Research Committee “Traction Characteristics of Trucks and Truck Combinations”
- Hoeprich, M.R. “The Analysis and Interactions of Tapered Rolling Element Bearing Raceway Stresses” International Rolling Element Bearing Symposium 94 April 11-14 1994 San Diego, CA
- Hoeprich, M.R. “Process for Deriving the Contact Geometry for Raceways and Rollers of a Rolling Element Bearing” October 31 1989
- Hoeprich, M.R. “Numerical Procedure for Designing Rolling Element Contact Geometry as a Function of Load Cycle” SAE Paper No. 850764 April 15-17 1985
- Hoeprich, M.R. “Rolling Element Bearing Contact Geometry Analysis” STLE Tribology Transaction 38 4 1995 879 882
- Springer, Thomas E. “Bearings Deliver More Power, Last Longer” Power Transmission Design June 1996