The bases of angular velocity plans for three-degree-of-freedom planetary automatic transmissions with nine and ten forward gears

The modern automotive strategy aims to decrease fuel consumption and harmful emissions. The best way to do this is to increase the number of stages in gearboxes. The design of planetary gearboxes is based on the synthesis of their kinematic schemes. This is quite a complex and time-consuming procedure that requires taking into account a large number of options. The resultant kinematic scheme must fully meet kinematic and power requirements of the developers and provide the possibility of their structural implementation. A method for the synthesis of three-degree-of-freedom kinematic planetary gearboxes based on the properties of the angular velocity plan of a complex planetary gear has been developed at Bauman Moscow State Technical University. According to this method, the synthesis of kinematic schemes is carried out in two stages. At the first stage, the basis of the angular velocity plan is constructed. Unlike the angular velocity plan, it contains all operating points with specified transmission ratios but does not have the required number of planetary gear sets and lockup clutches. At the second stage, an additional (so-called auxiliary) link is introduced to ensure the required number of planetary gear sets and lockup clutches. The presented research resulted in the bases of angular velocity plans that can be useful for synthesizing kinematic schemes of planetary gearboxes with nine and ten forward gears providing continuous power flows when changing the gears. Methods for constructing the zero lines of auxiliary links are suggested for each basis of angular velocity plans, which is necessary to transform the basis into the angular velocity plan.

References

[1] Behrooz Mashadi, David Crolla. Vehicle Powertrain Systems. John Wiley & Sons Ltd., 2012. 538 p.

[2] Harald Naunheimer, Bernd Bertsche, Joachim Ryborz, Wolfgang Novak. Automotive Transmissions. Fundamentals, Selection, Design and Application. Springer, Heidelberg Dordrecht, London, New York, 2011. 715 p.

[3] World’s First 9-Speed Automatic Transmission. Available at: http://www.zf.com/corporate/en/products/innovations/9hp_automatic_transmission/9hp_automatic_transmission.html (accessed 10 November 2014).

[4] Christoph Dörr. The new automatic transmission 9G-tronic from Mercedes-Benz. 12th International symposium automotive transmissions, HEV and EV drivers, Germany. 2013.

[5] Major product information: Automatic Transmission. Available at: http://www.aisinaw.co.jp/en/products/drivetrain/at/index.html (accessed 24 January 2014).

[6] The new 8-Speed Automatic Transmission Generation. Available at: http://www.zf.com/corporate/en/products/innovations/8hp_automatic_transmissions/8hp_autom (accessed24 January 2014).

[7] 7-speed AT for medium and large RWD vehicles JR710E/JR711E. Available at: http://www.jatco.co.jp/ENGLISH/products/stepat/jr710e.html (accessed 24 January 2014).

[8] Krasnen’kov V.I., Vashets A.D. Proektirovanie planetarnykh mekhanizmov transportnykh mashin [Design planetary mechanisms of transport vehicles]. Moscow, Mashinostroenie publ., 1986. 273 p.