Study On The Application Of Hydraulic Absorber In A Uninterrupted Shift Transmission

Uninterrupted shift transmission (UST) is a novel vehicle transmission concept. USTrealizes torque uninterrupted shift by combining parallel shaft-gear and multimode controlledshifter (MCS). As the velocity ratio changes very fast in the process of shifting, the alternateworking of two switch elements in overrunning clutch generates torsional vibration whichmakes the passengers uncomfortable. Other than that, torsional vibration causes transmissionto be fatigued. Thus, the study and design of absorber for UST is of great significance.A rotary hydraulic absorber is adopted based on consideration of the damping effect andthe damping device intergrated with UST. The structure, layout and damping principle ofhydraulic absorber is analyzed, after which the hydraulic absorber functional prototype isdeveloped.For further study on the damping characteristics of hydraulic absorber, the finite elementmodel of inner flow channel of the hydraulic absorber is established by Hypermesh, and thedamping characteristic of hydraulic absorber in the process of compression stroke is analyzedby Fluent.In order to verify the damping characteristics of hydraulic absorber, a hydraulic absorberbench experiment system is constructed. And in order to obtain the damping characteristics, anew method that can generate incentive torque in transmission is proposed to be used as theprinciple of damping characteristic experiment, which is later verified experimentally.According to the principle, the damped natural frequency is obtained. A mathematical modelof bench experiment system is established, and the damping ratio of hydraulic absorber isanalyzed. By using curve fitting which is base on time domain modal parameter identification,the damping ratio of hydraulic absorber is obtained. The result of the experiment shows thecorrectness of hydraulic simulation and feasibility of the damping device.By using Simdriveline, a UST driveline dynamics model is established with or withouthydraulic absorber module separately. The simulation result shows the one including absorbermodule has a smaller impact in the process of upshift. The result of driveline systemsimulation shows the feasibility of the damping device. In this dissertation, theoretical analysis, modeling and simulation, experimental researchare used to study the application of hydraulic absorber in UST. The theoretical, simulation andexperimental results are highly agreeable with each other, which provide a theoretical andtechnical guidance for further application of UST in vehicle.