Research on the mass unbalance response of an inner planetary gear reducer
A new inner planetary gear reducer with three axes is introduced. Three constructions and fixing techniques of the planetary gears are also introduced and compared with each other. Considering the meshing stiffness and damping of the gear pairs and the stiffness of the bearings, the dynamic governing equations of an inner planetary gear reducer with three axes are established based on the lumped mass method and corresponding deformation conditions. According to the different constructions of the reducer, the natural frequency and the mass unbalance response is investigated in frequency field. It is found that the natural frequency of the reducer with different numbers of inner planetary gears has almost the same frequency value. Mass unbalance force can not only result in bending vibrations, but also result in twisting vibrations. When the reducer has three inner planetary gears, the amplitude of the dynamic response is smallest.
Digital image processing method for static balance measurement of incomplete spherical rotor with air suspension
Measurement and calibration of mass imbalance for rotors are often indispensible as mass imbalance will cause undesired vibration and present serious problems accordingly. In this study, a new method based on digital image processing (DIP) to measure the mass imbalance of a special rotor with air suspension is introduced. By hunting the trace of tilt angle through several identification points on the rotor by DIP, the corresponding oscillating period will be determined, which in turn contributes to the calculation of mass imbalance. Two-dimensional monochrome charge-coupled device (CCD) and peripheral component interconnect (PCI) image board are applied in the experiment to capture the rotor's image, and several user interfaces are developed for image processing and curve fitting as well. Besides, the system error analysis and the comparison of experimental results with that of other related work are provided, which prove the effectiveness and accuracy of this DIP method.
Evaluation of Dynamic Factors for Spur and Helical Gears
This paper deals with the development of a generalized dynamic factor for spur and helical gears operating away from system resonances. The experimental results of the tests reported in the previous paper [1] are used in conjunction with mathematical simulation of the gear system and geometrical analysis of the tooth meshing action to develop a semi-empirical formula for dynamic tooth load. The formula takes into consideration the gear geometry and manufacturing parameters as well as the dynamic characteristics of the system.