| Gear rotor system is one of the widest movement transmission devices in all sorts of machine and mechanical equipment, its mechanical and working performance is very important influence to the whole machine. Due to the gear meshing, the vibration characteristics of gear rotor system and simple rotor system have a fundamental difference. The main difference is the gear rotor system has a bending-tensional coupling vibration, and it has a bending-tensional-axial-swing coupling for helical gear rotor system. If we do not consider the effect of coupling vibration, not only cause low precision, but also lose some important information, such as the new frequencies of mode coupling, tensional excitation caused lateral responses and so on. Therefore, research into the gear rotor system is very important from the point of view of system.Considering the static transmission error and geometric eccentricities of the gears, a general total degree of freedom dynamic model of a helical gear pair was established. Combining with the rotor systems, a finite element model of the multi-shaft helical gear rotor system was determined. This paper analyzed the inherent characteristics and dynamic response of the system, and the main contents include the following aspects:(1) This paper sets helical gear system as the research object, considering the static transmission error and geometric eccentricities of the gears, a general total degree of freedom dynamic model of a helical gear pair was established.(2) Combining with the rotor systems, a finite element model of the multi-shaft helical gear rotor system was determined. The inherent characteristics of the gear rotor system are analyzed.(3) In order to judge the dominant mode and rotor and better prediction of the failure parts, failure characters, and the optimal design on the dynamic structural characteristics of the rotor system structure, the method of use of modal strain energy and modal strain energy density to identify the dominant mode and rotor of the rotor system is proposed in this paper, which proves to be true when compared with mode shapes.(4) The effects of various kinds of parameters on the inherent characteristics of the system are analyzed.1) The different degree of freedom modal coupling;2) The different driving shafts, the rotation direction of driving shafts, gear rotation;3) Gear mesh stiffness, gear position angle, helical angle and transverse pressure angle.(5) Based on the API617, the unbalance response of gear rotor system is analyzed in set speed and variable speed independently. There is no peak existing in the system response within the speed range, also the value is within the API617. Therefore, it is safe and reliable for the system to run in this range.(6) Through establishing the dynamic model of gear eccentricity, the effect of unbalance response of the system which is produced by gear eccentricity is analyzed. Finally, the effect of the gear eccentricity is analyzed to the system response.(7) The finite element model of geared system is built by ANSYS. Through contact analysis, a variety of load static transmission error of gear is obtained. Then, consider the static transmission error, analyzed the dynamic response of the system. Finally, analyzes system dynamic response on different load.In this paper, dynamic characteristics of a helical gear rotor system was studied, and obtained the dynamic characteristics of the corresponding results by a large number of values calculated to provide the basis for further theoretical research and design of high-performance gear rotor system. |
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