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Collaborative manufacturing requiring both geometric and physical evaluations has been an increasingly important trend in the industrial applications of spiral bevel gears. It is an innovative attempt that design for six sigma (DFSS) is introduced to establish a model of above collaborative manufacturing system. In the DFSS-based modeling, in addition to establishing the basic framework, the related data-driven decision and optimization are proposed, respectively. The house of quality (HOQ) is firstly established to convert the voice of customer (VOC) into the critical to qualities (CTQs) and determine the geometric and physical evaluations. Then, the conventional machine setting modification is extended to the multi-objective optimization (MOO) modification considering both geometric and physical evaluations. The whole system is divided into the three data-driven sub-problems for their respective decision and optimization. First, the accurate measurement and compensation is used to operate the noise factors in the actual manufacturing. Second, a prescribed ease-off topography is identified as the target flank by MOO of the physical evaluations. An improved high-order modification of the optimal machine setting is performed to optimize the geometric performance. A case of study on measurement-modification-machining (3 M) collaborative manufacturing system is provided to verify the proposed model.

Comprehensive modification refers to a modification method that simultaneously performs lead crown modification and tooth profile modification, which is widely used in precision gear manufacturing. However, there are few time-varying meshing stiffness (TVMS) models of spur gears with comprehensive modification. Based on the actual manufacturing methods and slice theory, an improved analytical model (IAM) for calculating the TVMS considering the coupling modification is established. The model does not require to use the finite element method (FEM) to determine the correlation coefficients. The IAM is compared with the published models and verified by the FEM. The results show that the IAM has higher accuracy and efficiency in the calculation of lead crown modification, tooth profile modification and comprehensive modification. The gear bearing capacity of machining method 2 is better than that of method 1. It is useful to improve the calculation accuracy to choose the number of slices reasonably according to the modification amount.

The dynamic responses and load sharing features of a two-path split torque gear transmission system are investigated in this study. The possible combinations of shaft angles to ensure the gear pairs work properly are determined considering the adjacency relationship, concentric relationship, geometrical conditions and installation conditions. A dynamic model of the system considering time-varying mesh stiffness, backlash, static transmission error, stagger angle excitations and gyroscopic effects of gear body and flexible shaft is proposed. The natural characteristics of the system including natural frequencies and critical speeds are obtained. The influences of the shaft angle, asymmetric transmission error excitations and right-to-left stagger angle of double-helical gear teeth on the dynamic transmission error responses and load sharing features of the two-path split torque gear transmission system are investigated. Several references to determine the system parameters to improve the transmission property and load sharing performance of the system are provided based on the numerical simulation results.

Though finite length squeeze film dampers (FLSFD) are practically and effectively applied to vibration attenuation, they have not been popularly used in bevel gear systems (BGS) due to the limitations of the existing models of FLSFD. The present work proposes a general approach for modeling and calculating the nonlinear oil-film force of FLSFD, which is introduced into system motion equations to model the BGS supported on FLSFD mathematically. Comparisons with conventional methods show the superiorities of the proposed model in terms of computational accuracy and versatility. The damping characteristics of FLSFD are examined by comparing the dynamic behaviors of the BGS with and without FLSFD. Besides, the response sensitivity of the system to different parameters, including the length and radial clearance of FLSFD, is also discussed. The results show that FLSFD can significantly reduce the vibration amplitude passing through the critical speeds and suppress the nonlinear characteristics of the system, such as bistable state responses and jump phenomena. The results also reveal a dependence of the damping performance on the choice of the FLSFD design parameters.