The Simulation And Experimental Study On The Nitriding Distortion Of The Main Shaft Of Inclined Shaft Plunger Pump/Motor

Hydraulic pumps/motors are widly used in modern hydraulic transmission system.They can be found in light and heavy-duty hydraulic locomotives,motor vehicles,industrial built-in machinery,and military weaponry.With valve plate flow distributionstructure,they are easy to achieve high pressure and high speed,and their viability is good as well.Moreover,their costs of manufacturing and maintenance are relatively low.The problem with angle plunger pumps/motors is the nitriding distortion occurred to the hinge ball-joints of their drive shafts during the nitriding process.Hydraulic pump motor,the drive shaft torque role,on the spindle machining have driven plate,drive along the circumference of a circle on the tray seven "ball",in the shaft center also has a "ball",the ball with the ball head and the center pole on the connecting rod ball head of ball joint,connecting rod drives the cylinder rotate and push plunger reciprocating motion.A pair of sliding friction pairs formed by the ball socket and the ball head of the connecting rod,if the friction pair is worn faster,resulting in increased clearance,the internal leakage will be caused and the volume efficiency will be reduced.It is more likely to cause damage to the hinge ball head,affect the service life,and even cause the ball to die and the connecting rod is broken,causing the hydraulic pump to be damaged directly.Therefore,the spindle needs high surface hardness,high fatigue strength and good anti-overheating and anti-deformation properties,and the mechanical properties of spindle surface are guaranteed by nitriding treatment.This can significantly lower the precision of the ball-joints,and would increase the processing costs in later production processes.Therefore,it is very important to study how to control nitriding distortion of the ball-joint of the drive shaft.ANSYS finite element simulation is used in this paper to simulate the Static deformation deformation of the heat treatment which affects the denitrification distortion.Analyzes the influence of the Static deformation from different placement of drivespindle.Verity the simulationresultsthroughexperiment.About the affect of heat treatment Static deformation on nitridingdistortion.Through the orthogonal experiment,the temperature change of nitriding distortion and the structure stress caused by the volume increase of nitriding layer were studied.The following conclusions are obtained: In the process of nitriding,the heating speed factor has the greatest influence on the distortion of the hinge plate,and the increase of temperature is too slow or the increase of the isothermal platform will cause the distortion.Optimal nitriding process combination is:rateoftemperatureincrease 125 ℃ /h,use secondary nitriding process,the shaft furnace charging,cooling speed-90 ℃/h.