Theoretical And Experimental Research On The Transmission Performance Of High Speed And Heavy Load Double-helical Planetary Transmission Under Friction And Wear

Double-helical planetary gear transmission system has significant advantages,including small axial force,low noise,high load-bearing capacity,high transmission power and which is widely used in heavy load and high-power equipment such as marine,aerospace,aviation,and petroleum.With the advancement of modern industrial technology,industrial devices is developing toward to higher power density,lower vibration,lower noise,high reliability and ultra-high efficiency,which leads to requirements that are more stringent on the transmission performance for double-helical planetary transmission system.The double-helical planetary transmission system is considered as the research object and carries out the theoretical and experimental research on the transmission performance for the high-speed and heavy-load double-helical planetary transmission system considering friction and tooth surface wear.The focus of research is on the vibration characteristics and transmission efficiency of the doublehelical planetary transmission system,establishing a theoretical foundation for the highspeed and heavy-duty double-helical planetary transmission system to achieve low vibration and high efficiency.The main research work is summarized as follows:(1)A numerical analysis lubrication model for the high-speed and heavy-duty double-helical gear pairs is proposed,considering the surface roughness,the NonNewtonian properties of lubricant oil,the wear of the tooth surface and thermal effect.Based on the meshing characteristics of double-helical gears,the basic parameters of the lubrication model are calculated,and the control equations of the non-Newtonian fluid lubrication model considering wear,tooth surface roughness and thermal effects are established.The multi-grid method and the Gauss-Seidel relaxation iteration method are employed to solve the equations simultaneously.Then,the lubrication characteristics of the contact area are obtained.In addition,the distributions of oil film temperature,the oil film pressure,oil film thickness and friction coefficient are analyzed,and the effects of roughness surface,tooth surface wear,rotation speed and input torque are investigated.(2)Considering the coupling relationship between dynamic and tribological characteristics,a multi-degree-of-freedom gap-nonlinear dynamic model of doublehelical planetary transmission system is put forward by taking into consideration the influence factors,such as time-varying meshing stiffness,meshing impact,tooth surface wear,tooth surface friction and tooth surface temperature rise effect.Based on the theory of tooth surface wear and point-contact thermal elastohydrodynamic lubrication,a numerical iterative solution combination Runge-Kutta method and multi-grid method are used to carry out the coupled dynamics equations.Furthermore,the influence of gyro effect,eccentricity error,tooth surface wear and tooth surface temperature rise on the dynamic characteristics of the gear system are obtained.(3)A mathematical model of meshing efficiency of double-helical gear meshing pair based on dynamic meshing force is proposed.The power loss factor of the double-helical gear pair is deduced,and the meshing efficiency of the external meshing pair and the internal meshing pair of the double-helical planetary transmission system are calculated.Curves of meshing efficiency under different speed,different torque and different input power are discussed.Moreover,the influence of tooth surface wear,surface roughness and temperature rise on meshing efficiency are studied.(4)A connection constraint model of unit combination for double-helical planetary transmission system is established considering several sources of power losses such as gear meshing friction,windage,bearing friction and lubricant compression resistance.Subsequently,the efficiency calculation formula of planetary gear transmission system is deduced,and the method of power flow analysis for planetary gear transmission based on power loss mechanism is proposed.The energy characteristic state and power flow direction of the connection nodes for the planetary transmission unit are studied,and the power loss mechanism of the planetary transmission system unit are revealed.A hypergraph-based analysis method for the transmission efficiency of planetary gear trains is proposed,which realizes the efficiency calculation for planetary gear trains.The efficiency of a two-stage double-helical planetary transmission system is achieved using the proposed method.Moreover,the influence of input speed,input power,and lubrication state on transmission efficiency are investigated.(5)Three specimens with different surface roughness are tested in the multifunctional friction and wear test bench,the change law of friction coefficient and wear depth under different working conditions and different surface roughness are obtained,which validate the friction coefficient calculation model for the lubrication model.On the power enclosed test bench,the acceleration sensor is used to measure the vibration acceleration of the gearbox test point,and the non-contact torque sensor is used to measure the input and output torque,and the vibration and efficiency test of the gear transmission is carried out.The test results are compared with the theoretical calculation results,and the correctness of the lubrication model,dynamic model and transmission efficiency model proposed in this paper are verified.