Research On Dynamic Characteriscs And Damping Ring Vibration Reduction For High Speed Large Power Density Gear Transmission

In the area of machinery, automobile industries, wind power, aviation, aerospace and ship industries, gears are widely used as mechanical element for motion and power transmission. For raise the transmission efficiency and meet the harsh requirements of other special industries, the performance of modern gear transmission look forward to high speed, lightweight, large power density, low noise and integration. For lightweight, gears flexible deformation enlarges and the number of resonance region increases as the natural frequency reduces. Based on high speed large power density gear transmission, this paper focuses on the dynamic property considers effect of lightweight and damping ring. Results have great theoretical and engineering value for understanding the dynamic characteristics, damping ring vibration reduction technology, optimal design of high speed large power density gears.A coupling dynamic model containing multi-degree of freedom of bending-torsion-axial direction was proposed based on centralized parameter method which considers the damping ring. The nondimensionalize differential equation of motion was also obtained. An equivalent stiffness between spindle and bearing calculation method considering parameter of gear structure, working condition, elastic deformation of spindle was given by combining the theory of quasi-dynamic and finite element method. This dynamic equivalent stiffness method is able to calculate dynamic and static equivalent stiffness between spindle and bearing. Results show that, when excited speed is critical speed, the equivalent dynamic stiffness appears hump. Meanwhile, when load on gear increases, the axial equivalent stiffness of gear transmission system trends to axial stiffness of loose end bearing.Under the condition of meshing stiffness, transmission error and damping ring, system’s dynamic response is obtained by Runge-Kutta method and rigid bending-torsion-axial coupling gear transmission dynamics model with damping ring. For high speed large power density gears, increasing of web damping can be used to control the extending the amplitude of system response caused by lightweight. The damping ring has observable effect on controlling system vibration response and there is the most optimal structural parameter which will make gear transmission gets the best vibration damping effect.The modal reduction method and Adams were adopted to build rigid-flexible coupling multi-body dynamics model which coupled damping ring and the gear transmission system. In the model, the effects of large flexible deformation of damping ring and lightweight gears were considered. An improved coefficient of restitution calculation method was proposed. This method can be used to analysis flexible body dynamic characteristics considering elastic deformation, elastic-plastic deformation and finite plastic deformation. The results obtained from rigid-flexible coupling gear transmission with damping ring dynamic model showed that the thickness of web and rim can effectively reduce the fluctuation of gear rim and web axial vibration amplitude. Under the stable state, the flat-gate damping ring could make the fluctuation of gear rim and web great drop. Under the transient state, the flat-gate damping ring can not only greatly inhibited the fluctuation of gear axial vibration amplitude but also can significantly inhibit axial meshing force under side frequency vibration amplitude.In order to study the effects of lightweight and damping ring on gear transmission dynamic characteristics and the requirements under the condition of high speed and oil lubrication, a high speed gear’s test rig was developed. The test rig can simulate the condition of maximum speed of 24 kr/min, oil lubrication and adjustable working condition. The experiment results show that in the range of 15-24 kr/min excited speed, the axial vibration amplitude of rim and web increases largely with excited speed. Comparing to rim, the axial vibration amplitude of web is more sensitive to variation in load. Under the steady state, the damping ring can effectively axial vibration of web by a declining amplitude of 31.5%~71.4%. The effect of flat-gate knurling damping ring on suppression of axial vibrating deformation and decreasing of radiant noise seems to be more apparent compari ng with that of fracture-gate circlip damping and flat-gate damping. Under the transient state, the damping ring could effectively control the large fluctuation of deformation of rim and web, the transient time is also reduced. The contrast between theoretical and experimental analysis showed that the results by rigid and rigid-flexible multi-body gear transmission modal are same trend of dynamic characteristic as test result of dynamic characteristic. But there is large difference in numerical value.