Gear Powertrain Research Articles

New teeth surface and back (TSB) modification method for transient torsional vibration suppression of planetary gear powertrain for an electric vehicle

Advantages of planetary gear powertrain (PGT) for electric vehicles (EVs) are the high degree of efficiency, various reduction ratio, stress distribution by the planet gear and compaction in designing driving system. However there is noise in running at high rotational speed, so the transient torsional vibration suppression of the PGT for EVs become extremely essential and urgent. This study presents a 4 + N degree of freedom (DOF) nonlinear torsional system that essentially describes a PGT of EVs example, and further study on influence of novel TSB modification on transient vibration of planetary gear powertrain for an electric vehicle. In particular, the vibration of the PGT during the speed-up process, as excited by dynamic torque of motor generator (MG), time-varying mesh stiffness of front and back gear teeth, and also teeth backlashes, are investigated using a nonlinear torsional transient model. Then a full PGT model during the speed-up process is proposed and numerically solved to obtain the transient vibration acceleration. Dynamic response results of the PGT are also successfully compared and analyzed under different teeth backlashes. Finally, an improved genetic algorithm is applied to construct optimal relationship between the transient vibration and the TSB modification, and further the optimum three-dimensional TSB modification of sun-gear is finally obtained. The simulation and experiment results indicated that the proposed novel TSB modification method effectively suppressed the PGT transient vibration and vehicle jerk, at the same time, improved the ride comfort during the high-speed driving mode.

Analysis of a novel actively controlled split path automotive gear powertrain topology

Automotive powertrains are susceptible to noise and vibration borne from the dynamical excitation of the gear meshes, particularly at partial loads, such as whine and rattling. A novel design has been proposed, based on the subdivision of the power flow into parallel paths via a compact internal gear preloading subsystem. The design allows the real-time control of mesh stiffness, load sharing and backlash, thereby allowing the instantaneous optimisation of the dynamical response of the system and the elimination of rattling and whine at any torque and speed. This paper performs an analysis of the new topology and discusses some of its advantages over conventional and preloaded zero-backlash gear powertrain designs.

Analysis of a novel actively controlled split path automotive gear powertrain topology

Analysis of a novel actively controlled split path automotive gear powertrain topology