The Numerical Simulation Of Mesh Force Of External Gear Pump And Analysis Of Dynamic Characteristic

The calculation of gear engaging load is an important job about all study of gear system.It is a significant index to evaluate the bending fatigue strength and contact fatigue strength of gears.Gears are central parts of external gear pump,so calculating the load of gear is the main work in this thesis.Trapping phenomenon is an inherent characteristic of gear pump,trapping phenomenon need to be considering when we are calculating the engaging load.So it is a given to build up the modal of engaging load and to establish the simulation model.The main work is:The formula of minimum trapped area was build and it has been verified by virtual measurement,which has prepare for calculate the trapped pressure and engaging load.As a result,the trapped area is periodic along with bounce.The mathematic model has been established considering meshing stiffness and error,meshing stiffness which was calculated by transformation of gear teeth is periodic,and the periodic engaging load has been figured up using an example.The result is a peak value appears when a pair of teeth is meshing.On the contrary,the engaging load is stationary when two pairs teeth is meshing.Another model has been established considering trapped pressure.The drag torque which was generated by oil was analyzed.It comes out that drag torque which act on teeth is periodic in meshing cycle.The simulation model of gear engaging load was established,the load was solve by mathematic means.The result is closed to the mathematic modal,the result is a peak value appears when a pair of teeth is meshing,the engaging load is stationary when two pairs teeth is meshing.Modal analysis was figured up,as the result,the shell will never couple with gear pair.The fluid dynamics model of internal flow field in gear pump has been established,the static pressure in fluid was solved by numerical simulation.A s a result,the static pressure changed little when the pump has small size,maximum static pressure appears when teeth is meshing and the static pressure of the oil absorption cavity is minimum,which is closed to engineering practice.The thesis has provided a reliable method for calculating the gear engaging load,which is significant for physical designing and noise controlling.It also provided a method for solving transmission load of common gears.