Multi-Stage Transmission Theory And Application Of Single-pump And Multi-input Motor System

Hydraulic technology,with high specific power and convenient control,is widely used in the manufacturing,engineering machinery,military equipments,and other fields.It has become a important mean of modern mechanical transmission and control.But modern hydraulic technology still has some deficiency restricting its further development.For example,quantitative pump system not only has simple structure,low cost and convenient maintenance,but also has very low efficiency in some situations where actuators need fast and slow alternating work.Hydrostatic transmission technology applied in construction machinery walking system can make engine always work in the high efficiency range by automatically adjusting the displacement of pump.But when the actual load overrange the variable displacement range of pump,the efficiency will be greatly reduced.Focus on using the new double-rotor multi-input motor to solve the above two problems,this paper studies the transmission theory and application of multi-input motor systems.Firstly,the hydraulic systems composed of single-pump and multi-input motor are classified and regulated.According to the classification,each system is respectively studied and get a formula applies to all systems.Secondly,in view of the range of hydraulic pump variable displacement is limited in construction machinery hydrostatic transmission system,use the multi-input motor to remould a skid steer loader and get a whole hydraulic principle diagram,a whole layout,and a whole mathematical model.Then,using AMESim software to create a system simulation model,set parameters,simulate the system in four different conditions,and analyze the simulation results.Finally,a demonstration experiment on the hydrostatic transmission system with multi-input motor was done.The experimental results show that the transmission theory and simulation analysis are correct.The following conclusions are obtained.According to the formula of single-pump and multi-input motor system,some cases such as failure point,asymmetric reverse and repeated output in multi-input motor at work may occur.The main influencing factors are the displacement coefficient C,the working mode of multi-input motor and so on,which should be paid attention to in the practical application.Using the double-rotor multi-input motor to remould skid steer loader can not only meet the traditional hydrostatic transmission system,but also achieve constant torque multi-stage speed or constant speed multi-stage torque output through controlling the work mode of multi-input motor.But when the displacement of multi-input motor is small,system efficiency will decrease along with the larger displacement of pump.In order to avoid this situation,it is suggested that the displacement coefficient C of multi-input motor can be changed to make the speed isn’t very high.