| Based on the principle of power splitting,the hydraulic variable-speed planetary device combines the adjustable hydraulic torque converter with the planetary gear to realize the perfect combination of hydraulic speed control and mechanical transmission.It is a technology with wide range of applications,high efficiency and high transmission power.the adjustable hydraulic torque converter is the core stepless shifting component of the hydraulic variable-speed planetary.The traditional adjustable vane hydraulic torque converter has low efficiency under low load.The latest generation of hydraulic variable-speed planetary device uses a adjustable pump hydraulic torque converter to rise the efficiency under low load Such a hydraulic torque converter hydraulic model has high research value.(1)The paper first demonstrates that the two adjustable pump hydraulic torque converters can be used on the hydraulic variable-speed planetary devices to maintain a high overall transmission efficiency over a wide range of load variations.(2)This paper uses the LB46 hydraulic torque converter as the base type,and changes the pump wheel flow path to radial flow type to meet the requirements of the adjustable pump.the CFD technology is used for numerical simulation to calculate the efficiency of the hydraulic torque converter under different adjustable pump wheel opening degrees.The results verify that not all adjustable pump hydraulic torque converters will appear as the Krupp and Risholm-Smith type torque converters,the efficiency of the hydraulic torque converters are still high when the pump wheel opening is changed.(3)In order to explore the principle of adjustable pump hydraulic torque converter,a first-stage turbine is added in front of the second-stage guide vane on the basis of the original cyclic circular structure,the streamline of the new blade system is calculated at a speed ratio of 0.45,based on this,the inlet and outlet blade angles are modified,and the efficiency reaches a maximum of 88.7% when the modified hydraulic torque converter is at a speed ratio of 0.5.The speed range of hydraulic torque converter can reach 80% efficiency is 1.77,but compared with the speed range of rishoum hydraulic torque converter,it still has some shortcomings.(4)Further optimize the design of the hydraulic torque converter,taking the inlet and outlet angles of the turbine and the guide wheel as independent variables,the overall efficiency under the different pump impellers of the torque converter is the objective function,and the efficiency under the rated load is not less than 0.86 as the constraint conditions.By using the central composite point design method and multi-objective genetic algorithm,the blade angle of the inlet and outlet is solved The optimization results show that under the 25% pump wheel opening,the efficiency of hydraulic torque converter reaches 81.7%,4.7%higher than before optimization,The speed range of hydraulic torque converter can reach 80% efficiency is 2.3 Compared with the speed range of 2.22 of two pump wheel adjustable hydraulic torque converter with known characteristics,it can meet the requirements of its efficiency characteristics. |
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