See discussions, st ats, and author pr ofiles f or this public ation at : https://www .researchgate.ne t/public ation/306293024 Reduced Length Eight_Velocity Automatic T ransmissions Article    in  Journal of Univ ersity of Bab ylon f or Pur e and Applied Scienc es · August 2016 CITATIONS 0READS 1,961 3 author s, including: Some o f the author s of this public ation ar e also w orking on these r elat ed pr ojects: GRAPH-BASED AL GORITHM F OR PO WER CIRC ULATION AND EFFICIENC Y ANAL YSIS OF A PL ANET ARY GEAR REDUCER View pr oject Robotic Motion Planning in Dynamic Envir onments View pr oject Essam Lauibi Esmail Univ ersity of Al-Qadisiy ah 64 PUBLICA TIONS    173 CITATIONS     SEE PROFILE Farah Kamil Al-F urat Al-A wsat T echnic al Univ ersity 11 PUBLICA TIONS    61 CITATIONS     SEE PROFILE All c ontent f ollo wing this p age was uplo aded b y Farah Kamil on 20 A ugust 2016. The user has r equest ed enhanc ement of the do wnlo aded file.Journal of Babylon University/Engineering Sciences/ No.( 3)/ Vol. (24): 2016 748 Reduced Length Eight_Velocity Automatic Transmissions Essam L. Esmail1 Farah Kamil Abid Muslim Abdullh Kawaf Jaber University of Qadisiya Technical Institute/ Dewaniya Technical Institute/ Dewaniya Dr.essamesmail@yahoo.com Abstract Although there are many epicyclic -type automatic transmissions in production, some of the related configurations are still far from attaining maximum sequential velocity ratios. This work in part wi ll attempt to attain the maximum possible velocity rat ios for any given epicyclic gear train. A methodology for the design of two-ring Ravigneaux -type epicyclic gear transmissions for automobiles is presented. First, based on the kinematic nomographs of the corresponding basic gear ratios, clutching - sequences are enumerated. Second, a planar -graph representation is used to arrange the desired clutches for each possible clutching sequence into the epicyclic gear mechanism. Then, with the above methods, the designs of the epicylic gear mechanisms are given for d emonstrating the feasibility of the proposed methodology. Next, following the general trend of increased shift stages and a wider range of velocit y ratios, n ew six -, seven - and eight -velocity automatic transmissions are enumerated from the two -ring nine - link Ravigneaux gear mechanisms. The result of this work shows that the nine -link two -DOF Ravigneaux - type epicylic gear mechanisms could reach eight -forward speeds at most. It is a major breakthrough to design eight -speed automatic transmissions from the nine-link Ravigneaux gear mechanism since it has only nine links. This structural design has realized a reduced length automatic transmission , while having minimal number of gears . The methodology can be applied to any transmission mechanism depending on its kinematic and geometric constraints. Keywords : Automatic Transmission, Clutching -Sequence, Epicyclic Gear Train, Eight -Velocity, Feasibility Graphs, Nomographs, Ravigneaux Gear Set, Systematic Design. ﺍﻟﺨﻼﺼﺔ ﺒﺎﻟﺭﻏﻡ ﻤﻥ ﻭﺠﻭﺩ ﺍﻟﻌﺩﻴﺩ ﻤﻥ ﺁﻟﻴﺎﺕ ﻨﻘل ﺍﻟﺤﺭﻜﺔ ﺍﻵﻟﻴﺔ ﻓﻲ ﺴﻭﻕ ﺍﻻﻨﺘﺎﺝ ﻓﺄﻥ ﺒﻌﺽ ﺘﻠﻙ ﺍﻵﻟﻴﺎﺕ ﻤﺎ ﺯﺍﻟﺕ ﺒﻌﻴﺩﻩ ﻤﻥ ﺍﻟﻭﺼﻭل ﺍﻟﻰ ﺍﻟﻘﻴﻤﺔ ﺍﻟﻘﺼﻭﻯ ﻤﻥ ﺍﻟﻨﺴﺏ ﺍﻟﺴﺭﻋﻴﺔ ﺍﻟﻤﺘﺎﺤﺔ ﻟﻬﺎ. ﺃﻥ ﻤﻥ ﺒﻌﺽ ﺃﻫﺩﺍﻑ ﺍﻟﺒﺤﺙ ﻫﻭ ﻤﺤﺎﻭﻟﺔ ﺍﻟﻭﺼﻭل ﺍﻟﻰ ﺍﻟﻌﺩﺩ ﺍﻻﻗﺼﻰ ﻤﻥ ﺍﻟﻨﺴﺏ ﺍﻟﺴﺭﻋﻴﺔ ﺍﻟﻤﺘﺎﺤﺔ ﻷﻱ ﻤﻨﻅﻭﻤﺔ ﻨﻘل ﺴﺭﻋﻪ. ﻓﻲ ﺍﻟﺒﺤﺙ ﺍﻟﺤﺎﻟﻲ ﺘﻡ ﺍﺴﺘﻌﺭﺍﺽ ﻁﺭﻴﻘﻪ ﺘﺼﻤﻴﻡ ﺁﻟﻴﺎﺕ ﻨﻘل ﺍﻟﺤﺭﻜﺔ ﺍﻟﻜﻭﻜﺒﻴﺔ ﻤﻥ ﻨﻭﻉ ﺭﺍ ﻓﻜﻨﻭﺯ ﺜﻨﺎﺌﻴﻪ ﺍﻟﺘﺭﺱ ﺍﻟﺤﻠﻘﻲ. ﻓﻲ ﺍﻟﺒﺩﺀ ﻭﺒﺎﻻﻋﺘﻤﺎﺩ ﻋﻠﻰ ﻤﺨﻁﻁﺎﺕ ﺍﻟﻨﻭﻤﻭﻏﺭﺍﻑ ﺍﻟﻤﻨﺎﻅﺭﺓ ﻟﻠﻨﺴﺏ ﺍﻟﺘﺭ ﺴﻴﺔ ﺍﻷﺴﺎﺴﻴﺔ ﻓﻘﺩ ﺘﻡ ﺘﻌﺩﺍﺩ ﻜﺎﻓﺔ ﺘﻌﺎﺸﻴﻕ ﺍﻟﺘﺭﻭﺱ. ﺜﻡ ﺘﻡ ﺍﺴﺘﻌﻤﺎل ﺘﻤﺜﻴل ﺍﻟﻤﺨﻁﻁ ﺍﻟﻤﺴﺘﻭﻱ ﻟﺘ ﺭﺘﻴﺏ ﺘﻌﺎﺸﻴﻕ ﺍﻟﺘﺭﻭﺱ ﺍﻟﻤﻤﻜﻨﺔ ﻟﻜل ﺘﺘﺎﺒﻊ ﺘﻌﺎﺸﻴﻕ ﺘﺭﻭﺱ ﻤﺘﺎﺡ ﻵﻟﻴﺔ ﻨﻘل ﺍﻟﺤﺭﻜﺔ. ﺜﻡ ﺒﺎﺴﺘﻌﻤﺎل ﺍﻟﻁﺭﻕ ﺍﻋﻼﻩ ﺘﻡ ﺍﺴﺘﻌﺭﺍﺽ ﺘﺼﺎﻤﻴﻡ ﺁﻟﻴﺎﺕ ﻨﻘل ﺍﻟﺤﺭﻜﺔ ﺍﻟﻜﻭﻜﺒﻴﺔ ﻷﺜﺒﺎﺕ ﺃﻤﻜﺎﻨﻴﺔ ﺍﺴﺘﺨﺩﺍﻤﻬﺎ ﻋﻤﻠﻴﺎ . ﺒﻌﺩﻫﺎ ﻭﺒﺄﺘﺒﺎﻉ ﺍﻟﺴﻴﺎﻕ ﺍﻟﻌﺎﻡ ﻓﻲ ﺯﻴﺎﺩﻩ ﻋﺩﺩ ﺘﺒﺩﻴﻼﺕ ﺍﻟﺴﺭﻋﺔ ﻭﺍﺘﺴﺎﻉ ﻤﺩﻯ ﺍﻟﻨﺴﺏ ﺍﻟﺴﺭﻋﻴﺔ ﻓﻘﺩ ﺘﻡ ﺘﻌﺩﺍﺩ ﻜﺎﻓﺔ ﺘﻌﺎﺸﻴﻕ ﺍﻟﺘﺭﻭﺱ ﺴﺩﺍﺴﻴﻪ ﻭﺴﺒﺎﻋﻴﺔ ﻭﺜﻤﺎﻨﻴﺔ ﺍﻟﺴﺭﻋﺔ ﻟﻶﻟﻴﺎﺕ ﺍﻟﻜﻭﻜﺒﻴﺔ ﻨﻭﻉ ﺭﺍﻑ ﻜﻨﻭﺯ ﺜﻨﺎﺌﻴﺔ ﺍﻟﺘﺭﺱ ﺍﻟﺤﻠﻘﻲ . ﻭﻗﺩ ﺒﻴﻨﺕ ﻨﺘﺎﺌﺞ ﺍﻟ