| Gear transmission is one of the most widely used transmission modes.As a kind of intersecting shaft transmission,bevel gear transmission system plays an important role in practical engineering because it has the capacity of changing the direction of transmission.However,the system failure in bevel gears,which are commonly used in helicopter transmission system,often brings giant losses due to the excessive vibration.Therefore,it is of great significance to effectively restrain the vibration of bevel gear transmission system.In order to solve the vibration problem of bevel gear transmission system,a method of damping vibration attenuation was proposed in this research.The test bench for the vibration reduction experiments was built with three different dampers separately,the integral squeeze film damper,the viscous damper and the magnetorheological damper.Theoretical analysis and simulation of bevel gear transmission system were conducted to study the vibration reduction effect and characteristics.The main contents and conclusions of this paper are as follows:(1)According to the theory of gear system dynamics,the cause of vibration of bevel gear transmission system was analyzed.The bevel gear transmission system was modeled for the static analysis and modal analysis with ANSYS software,where the first to the sixth natural frequencies and modes of the bevel gear transmission system were calculated.(2)In the experiment with integral squeeze film damper(ISFD),the vibration reduction of bevel gear transmission system with rigid support and ISFD elastic damping support installed at different rotating speeds separately was analyzed.The results showed that the peak acceleration of the bearing seats can be reduced by more than 40%on average in a wide speed range with the ISFD elastic damping support,and the initial shock vibration and modulation of bevel gear transmission system were also improved.(3)In the experiment of vibration reduction with viscous damper,several comparative studies of bevel gear transmission system vibration were carried out under different circumstances.The changes of the conditions were based on the existence,the position and the installation requirement of the damper in the experiment.The results showed that the peak acceleration of the bearing seats decreased more than 50%on average in a wide speed range after the installation of viscous damper.The closer the viscous damper was installed to the vibration source,the better the vibration reduction effect would be.In addition,the vibration reduction result would be better when the dampers were installed on both shafts compared to that when the damper was installed on one shaft.(4)In the experiment with magnetorheological damper,vibration reduction of bevel gear transmission system was analyzed with the comparison between the installation and energization of the damper.The experiment was repeated after altering the position of dampers.The results showed that the peak acceleration of the bearing seats decreased more than 60%on average in a wide speed range after the magnetorheological dampers were installed and energized.Also,the shock vibration and modulation of bevel gear transmission system could be effectively improved.Similarly,the closer the magnetorheological damper was installed to the vibration source,the better the vibration reduction performance would be. |
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