To investigate the dynamical load sharing behaviors of multi-floating components in the heavy load planetary gear system, a multi-floating planetary gear system that includes a floating central component and a quasi-floating planet flexible supporting pin is employed. Then a 21 degree of freedom lumped parameters dynamical model of this system is presented to study the dynamical load sharing behaviors. Some influencing factors, such as supporting stiffness, positions error of sun or carrier, and external input load are analyzed on the dynamical load sharing of the planetary gear system with multi-floating components. The results demonstrate that the load sharing condition of the system is best when both the sun gear and planet gears are multi-floating at the same time. When the planet gear position errors remain constant, reducing the flexible pin stiffness of planet gear or increasing external input load can effectively improve the load sharing. These conclusions are verified by the relevant experiments.
The structure of flexible pin-type planetary gear systems used in wind turbine gearboxes can improve the load sharing ability of planets while saving space unlike straddle-type carriers. However, the nonlinear dynamic characteristic of this type of system is not fully developed. This work presents a coupled lumped-parameter dynamic model to demonstrate nonlinear effects. Gear contact loss nonlinearity and bearing clearance nonlinearity are integrated into this dynamical model, and the effects of flexible pins on the nonlinear dynamic responses are discussed. The conclusions made are as follows: lower flexible pin stiffness can significantly reduce nonlinear effects; when pin stiffness is increased, contact loss still occurs in positions of strong vibration even if the planet gear bearings have higher orders of magnitude of tangential load in the wind turbine gearbox; dynamic response peaks are asymmetric with a frequency sweep; only left oblique "Soft" jumps occur, and the right oblique "Hard" jump phenomena rarely occur; planet gear supporting the bearing clearance exists; and vibration chaos occurs in positions of strong vibration.
Of late, wire arc additive manufacturing (WAAM) is extensively used in the aerospace and automotive fields to produce large complex metallic components. The water‐bath method is applied for active cooling to address the heat accumulation problem in WAAM. Herein, the modified water‐bath method with a changing level is used to realize different phase transformations, and the microstructure and mechanical properties of the sample are investigated. Heat accumulation in the sample is eliminated using the modified water‐bath method. Furthermore, the microstructure of the fabricated sample shows a mixture of polygonal ferrite (PF), upper bainite (UB), and lath bainite (LB). Layer bands are formed in the entire sample, except in the final layer, and equiaxed ferrite (EF) and an increased fraction of PF appear in these zones. The microhardness and tensile property are enhanced due to the fine LB. The considerable difference in the microhardness between LB and PF causes an obvious wave of hardness, and the tensile property along the horizontal direction is better than the vertical. This study is expected to help broaden the application of the water bath in the microstructure control.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.