重型拖拉机液压机械无级变速箱冷却润滑油液的分配优化

Oil distribution optimization of cooling and lubrication for hydro-mechanical continuously variable transmission of heavy-duty tractor

[目的]为了实现重型拖拉机液压机械无级变速箱(hydro-mechanical continuously variable transmission,HMCVT)内部各个零件的良好润滑,提出一种冷却润滑油路的优化方法,实现油液合理分配。[方法]采用计算流体力学(Computational Fluid Dynamics,CFD)仿真与试验验证相结合的方法获取样本数据,利用径向基(radial basis function,RBF)神经网络建立出口孔径与出口流量的拟合函数,并构建以出口流量与目标流量误差平方和为优化目标的优化函数,运用惩罚函数法与遗传算法优化获得流量误差最小的流道结构参数。[结果]建立的CFD模型仿真结果与试验结果误差均小于10%,说明利用CFD方法计算润滑油路各出口流量值是切实可行的。利用RBF神经网络方法拟合的孔径-流量函数具有很高精度,决定系数均在0.95以上,优化后的冷却润滑油液分配更加合理,与目标流量值误差在5%以内。[结论]本文提出的冷却润滑油液合理分配的油路优化设计方法,能够减少设计成本,准确实现油液的精确分配,为变速箱润滑油路的设计提供了理论依据。

[Objectives]In order to achieve effective distribution of the lubricant in the hydro-mechanical continuously variable transmission(HMCVT)of heavy-duty tractors,an optimization method for the oil-path was proposed.[Methods]First,the combination of Computational Fluid Dynamics(CFD)and test verification were applied to obtain sample data.Then,the fitting function of outlet aperture and outlet flow was established by radial basis function(RBF)neural network.The optimization function was constructed by taking the sum of the squared errors of the outlet flow and the target flow as the objective.Finally,the penalty function approach and genetic algorithm were applied to obtain the flow-path structure parameters with minimized distraction.[Results]It was feasible to use the CFD method to calculate the outlet flow value,for the error between the CFD and the test was less than 10%.The aperture-flow function had high accuracy which was fitted by the RBF neural network,and the determination coefficients were all above 0.95.The optimized error with the target was within 5%,which indicated the distribution of the lubricant was more effective.[Conclusions]An optimization method for the oil-path was proposed in this paper to improve the effective distribution of the lubricant.The method which reduced designed costs and distributed oil accurately,provided a theoretical basis for the design of the transmission lubricating oil-path.