Design And Analysis Of Hydro-electric Hybrid Continuously Variable Transmission

With the rapid increase of car ownership in various countries,it greatly facilitates people’s daily travel and promotes the rapid development of the world economy.At the same time,a series of negative effects such as energy shortage,environmental pollution and traffic congestion also follow.At present,the transportation field is still highly dependent on non renewable energy.Therefore,reducing automobile energy consumption is the most important problem for green sustainable development.As the core component of automobile,the performance of transmission is directly related to the working efficiency,stability and energy consumption of automobile.CVT is favored because it can realize the continuous change of transmission ratio under fixed drive.Therefore,CVT has great development potential and broad application prospect.CVT is mainly divided into hydraulic transmission,mechanical transmission and electric transmission.Due to the limitations of its single transmission mode,the compound CVT,which integrates the advantages of various CVT modes and makes up for its shortcomings,has emerged and developed rapidly.At present,there are mainly two kinds of hydro mechanical transmission and electro-mechanical transmission,but the application field is still relatively single.Therefore,this paper proposes a scheme of hydro-electric hybrid continuously variable transmission,which realizes continuously variable transmission through pump structure,and realizes energy supplement and braking energy recovery and reuse through motor structure.In this paper,a kind of hydro-electric hybrid continuously variable transmission is taken as the research object,its overall structure and working mechanism are analyzed and combed in detail,the method of realizing variable speed of hydro-electric hybrid continuously variable transmission and its corresponding basic working conditions are described,and the principle of dual rotor variable piston pump which is composed of the transmission is analyzed.The structural design and dimension parameter calculation of the main parts(including plunger,cylinder block,transmission shaft,etc.)of the pump are carried out,and the parameters are preliminarily checked.The 3D model is established by Solid Works,and then imported into Adams and ANSYS Workbench respectively for static finite element analysis of parts and dynamic simulation analysis of the whole structure.The analysis results show that the design parameters meet the motion requirements.According to the calculation and analysis results,the hydraulic model of the pump is established by AMESim and the hydraulic parametric simulation is carried out.The simulation results verify that the design parameters of the pump body structure can meet the preset requirements of the transmission working conditions,and preliminarily demonstrate the feasibility of the scheme.Then,a surface mounted permanent magnet synchronous motor structure is added to the aforementioned two-rotor variable axial piston pump.The operating principle of surface mounted permanent magnet synchronous motor drive and double-rotor variable axial piston pump drive surface mounted permanent magnet synchronous generator are elaborated,and their structural parameters are designed and calculated based on pump structure.Ansoft Maxwell software is used to build the two-dimensional model of the motor structure and carry out electromagnetic simulation analysis of static and transient magnetic fields.The results show that the designed motor structure can meet the requirements.At the same time,the feasibility of installing the motor structure on the pump structure is preliminarily demonstrated.Finally,MATLAB/Simulink ideal mathematical model of power flow is established for the complete transmission,and reasonable parameter variables are set according to the preset operating conditions to carry out simulation calculation.The output shows that the driven motor can only be driven by the driven motor motor or high-pressure accumulator under low speed conditions.At slightly higher speeds,driven by a slave motor motor motor and a high-pressure accumulator.At higher speeds,the driven motor is driven by the active pump and energy is recovered through the active pump generator,the external reservoir,and the driven motor generator.At highest speeds,the active pump drives the driven motor while supplying energy through the high-pressure accumulator and the driven motor motor motor motor.At any time,the output speed can be dynamically adjusted by the swing angle of the slave motor.When the output is negative,the output is reversed.When the brake is short,the energy is recovered by the active pump generator,the external reservoir and the slave motor generator.When the emergency brake is applied,the high-pressure accumulator and the slave motor motor supply energy to provide the reverse instantaneous high-speed output.The rationality and function of the hydro-electric hybrid continuously variable transmission are theoretically verified by the simulation analysis of the parts and the whole of the hydro-electric stepless transmission proposed in this paper from mechanical structure,hydraulic model,electromagnetic field to mathematical model.It is proved that the proposed transmission can accommodate various speed requirements and achieve wider speed regulation by changing engine speed,size parameters of active pump and driven motor,swing angle,motor power,flow rate provided/recovered by external accumulator/accumulator,etc.to meet operating conditions in more fields.It provides a certain reference for the further research of the hydro-electric hybrid continuously variable transmission.