Based on the theory of hydro-mechanical transmission system, a new kind of gear shifting control scheme to improve work efficiency of hydro-mechanical transmission system was designed. By describing the work principles of crucial components mathematically, the dynamic model of hydro-mechanical transmission was constructed according to modular modeling method. The proposed efficient type shifting strategy was embedded in aforementioned model to predict its performance. The simulation results indicated the proposed strategy could improve hydro-mechanical transmission efficiency.
The brake performance of a hydrodynamic tractor-retarder assembly, which is the combination of torque converter and hyaulic retarder, was studied to explore its work mechanism. Spiral vortex distribution pattern of internal flow field in the assembly was discovered on the basis of reasonable boundary condition, where runaway speed of stator was determined by CFD analysis. Comparison of experimental data and flow field analysis shows that accurate brake performance of hydrodynamic tractor-retarder assembly can be calculated only by 3D flow field analysis presently and numerical simulation results is close to experimental data, and approximate linear relationship exists between runaway speed of stator and rotating speed of pump.
In order to meet the design requirements, the wet shifting clutch was designed based on secondary development of Pro/E. The basic principle of parametric design and the system composition of Pro/Toolkit application program were introduced. The three-dimensional template of wet shifting clutch was established. The VC++6.0 programming platform was utilized. The application program interface was set up by using the synchronous mode of Pro/Toolkit. The regeneration of wet shifting clutch was completed. The parametric design about the key sizes in the key parts and assembly relationship of the wet shifting clutch were realized. The convenient design of wet shifting clutch was achieved. The effective method could be provided for the parametric design of other complex parts.
In the deep-hole drilling process, chips can not be easily removed, so the influence factors of the negative-pressure removing-chips were analyzed on the existing DF negative-pressure removing-chip mechanism by the hydraulic pressure theory and the injection angle κ and negative pressure gap S were analyzed with FLUENT software. The results show that negative pressure effect were best in 32°of κ and 0.4 mm of S and negative pressure effect are better in 28°of κ and 0.5mm of S , which lay good theoretical foundation for the optimization and characteristics of negative pressure mechanism in near-dry deep-hole drilling.
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