Performance Evaluation of a Driving Power Transmission System for 50 kW Narrow Tractors

  • Hong, Soon-Jung (Rural Human Resource Development Center, Rural Development Administration) ;
  • Ha, Jong-Kyou (Tractor R&D (Center), LS Mtron Ltd.) ;
  • Kim, Yong-Joo (Department of Biosystems Machinery Engineering, College of Agricultural and Life Sciences, Chungnam National University) ;
  • Kabir, Md. Shaha Nur (Department of Agricultural and Industrial Engineering, Faculty of Engineering, Hajee Mohammad Danesh Science and Technology University) ;
  • Seo, Young Woo (Department of Biosystems Machinery Engineering, College of Agricultural and Life Sciences, Chungnam National University) ;
  • Chung, Sun-Ok (Department of Biosystems Machinery Engineering, College of Agricultural and Life Sciences, Chungnam National University)
  • Received : 2018.02.07
  • Accepted : 2018.02.25
  • Published : 2018.03.01


Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.


Grant : Development of Gathering Type Potato Harvester

Supported by : Rural Development Administration


  1. Ahn, S., J. Choi, S. Kim, J. Lee, C. H. Choi and H. Kim. 2015. Development of an integrated engine-hydro-mechanical transmission control algorithm for a tractor. Advances in Mechanical Engineering 7(7): 1-18.
  2. Bilski, B. 2013. Audible and infrasonic noise levels in the cabins of modern agricultural tractors - does the risk of adverse, exposure-dependent effects still exist? International Journal of Occupational Medicine and Environmental Health 26(3): 488-493.
  3. Capalbo, S. M. and M. Denny. 1986. Testing long-run productivity models for the Canadian and U.S. agricultural sectors. American Journal of Agricultural Economics 68(3): 615-625.
  4. Cavallo, E., E. Ferrari, L. Bollani and M. Coccia. 2014a. Strategic management implications for the adoption of technological innovations in agricultural tractor: the role of scale factors and environmental attitude. Technology Analysis & Strategic Management 26 (7): 765-779.
  5. Cavallo, E., E. Ferrari, L. Bollani and M. Coccia. 2014b. Attitudes and behaviour of adopters of technological innovations in agricultural tractors: A case study in Italian agricultural system. Agricultural Systems 130:44-54.
  6. Chang, D. I., M. S. Kim, K. D. Kim, Y. K. Huh, S. O. Chung and B. K. Cho. 2010. Development of a 50 kW tractor for European orchards. Annual Research Report. Jeonju, Republic of Korea: Center for IT Convergence Agricultural Machinery.
  7. Cho, J. M. 2003. Analysis of pressure modulation control and design parameters of powershift shuttle hydraulic clutch for tractor. MS thesis. Cheonan: Korea University of Technology and Education, Department of Mechanical Engineering.
  8. Choi, S. H., H. J. Kim, S. H. Ahn, S. H. Hong, M. J. Chai, O. E. Kwon, S. C. Kim, Y. J. Kim, C. H. Choi and H. S. Kim. 2013. Modeling and simulation for a tractor equipped with hydro-mechanical transmission. Journal of Biosystems Engineering 38(3): 171-179.
  9. Chung, S. O., Y. J. Kim, M. C. Choi, K. H. Lee, J. K. Ha, T. K. Kang and Y. K. Kim. 2016. Development of a hydraulic power transmission system for the 3-point hitch of 50-kW narrow tractors. Korean Journal of Agricultural Science 43(3): 450-458.
  10. Guzzomi, A. and V. Rondelli. 2013. Narrow-track wheeled agricultural tractor parameter variation. Journal of Agricultural Safety and Health 19(4): 237-260.
  11. Harris, K. J. and J. K. Jensen. 1964. John Deere power shift transmission. SAE Technical Paper 640052.
  12. Ha, J. K. 2015. Development of power transmission system for orchard tractor. PhD diss. Daejeon: Chungnam National University, Department of Agricultural Machinery Engineering.
  13. ILO, 1987. Safety in The Working Environment. International Labour Conference, Geneva, Switzerland: ILO.
  14. ISO. 2015. ISO-5131: Acoustics - Tractors and machinery for agriculture and forestry - Measurement of noise at the operator's position - Survey method. Geneva, Switzerland: International Organization for Standardization.
  15. Jung, G. H. 2013. Gear train design of 8-speed automatic transmission for tractor. Journal of Korean Society Fluid Power Construction Equipment 10(2): 30-36 (in Korean with English abstract).
  16. Kabir, M. S. N. 2015. Comfort evaluation and classification of agricultural tractors considering safety factors. PhD diss. Daejeon, Republic of Korea: Chungnam National University, Department of Agricultural Machinery Engineering.
  17. Kabir, M. S., Ryu, M. J., Chung, S. O., Kim, Y. J., Choi, C. H., Hong, S. J and J. H. Sung. 2014. Research trends for performance, safety, and comfort evaluation of agricultural tractors: A review. Journal of Biosystems Engineering 39(1): 21-33.
  18. KAMICO (Korea Agricultural Machinery Industry Cooperative) and KSAM (Korean Society for Agricultural Machinery). 2016. Agricultural Machinery Yearbook Republic of Korea. Korean Society for Agricultural Machinery. Available at
  19. Kechayov, D. and A. Trifonov. 2003. Noise effect of tractor stayer 942 upon the subsidiary agricultural workers. Journal of Environmental Protection and Ecology 4(4): 831-835.
  20. Kim, B. G., W. O. Lee, S. Y. Shin, H. K. Kim, C. H. Kang and J. Y. Rhee. 2009. Analysis of determining factors for power size of a tractor. Journal of Biosystems Engineering 34(1): 8-14 (in Korean, with English abstract).
  21. Kim, H. G., Y. J. Jo, C. S. Kim, Y. H. Han and D. C. Kim. 2016. Design improvement of mechanical transmission for tracked small agricultural transporters through gear strength analysis. Journal of Biosystems Engineering 41(1): 1-11.
  22. Lee, K. H. 1990. Spur and helical gear design for manual transmission. Journal of the Korean Society of Automotive Engineers 12(6): 3-10 (in Korean).
  23. Lee, I. Y., S. N. Yun, K. U. Yang, P. Y. Huh and D. G. Lee. 1996. Performance improvement of clutch actuating hydraulic control system at semi-automatic transmission for construction vehicles. Transactions of Korea Society of Automotive Engineers 4(3): 10-21 (In Korean, with English abstract).
  24. Lee, P. U, S. O. Chung, C. H. Choi, Y. J. Park and Y. J. Kim. 2016. Analysis of the effects of operating point of tractor engine on fatigue life of PTO gear using simulation. Korean Journal of Agricultural Science 43(3): 441-449.
  25. Nelson, D. I., R. Y. Nelson, M. Concha-Barrientos and M. Fingerhut. 2005. The global burden of occupational noise-induced hearing loss. American Journal of Industrial Medicine 48(6): 446-458.
  26. OECD. 2018. OECD code 2: Standard code for the official testing of agricultural and forestry tractor performance. Parish, France: OECD. Available at
  27. Park, Y. J., S. C. Kim and J. G. Kim. 2016a. Analysis and verification of power transmission characteristics of the hydromechanical transmission for agricultural tractors. Journal of Mechanical Science and Technology 30 (11): 5063-5072.
  28. Park, Y. J., J. G. Kim and G. H. Lee. 2016b. Characteristic analysis of planetary gear set of hydromechanical transmission system of agricultural tractors. Journal of Biosystems Engineering 41(3): 145-152.
  29. Raikwar, S., V. K. Tewari, S. Mukhopadhyay, C. R. B. Verma and M. S. Rao. 2015. Simulation of components of a power shuttle transmission system for an agricultural tractor. Computers and Electronics in Agriculture 114:114-124.
  30. SK (Statistics Korea). 2016. Agricultural area statistics in 2015. Available at
  31. Yun, C. J. 1998. Analysis and control of the clutch hydraulic control system for a variable speed drive independent quality. MS thesis. Seoul: Seoul National University, Department of Mechanical Design and Production Engineering.