Papers by Author: Guang Lei Liu

Abstract: The time varying meshing stiffness of normal and cracked spur gears of planetary gear train is studied by applying the unit normal forces at mesh point on the face width along the line of action of the single gear tooth in FE based software Ansys Workbench 14.5. The tooth deflections due to the applied forces at one mesh point are noted and a deflection matrix is established which is solved using Matlab to get net deflection and finally the meshing stiffness of gear tooth at particular mesh point. The process is repeated for other mesh points of gear tooth by rotating it to get meshing stiffness for whole gear tooth.

Abstract: In order to precisely control the meshing performance of spiral bevel gear pair, this paper represents a quantitative evaluation method using transmission error curve and tooth face contact trace. The design, using local synthesis method, obtains the manufacturing parameters of gear pair and forms the tooth face of spiral bevel gear. This paper accomplishes the quantitative evaluation by the following methods: using tooth contact analysis (TCA) to obtain actual transmission error curve and tooth face contact trace; quantitatively evaluating the transmission error curve by comparing the web values of actual and preset theoretical transmission error curves; quantitatively evaluating the tooth face contact trace by comparing the requirements (such as in shape, size and position) defined for spiral bevel gear tooth face contact trace and the corresponding parameters of an externally-connected rectangle, which surrounds the tooth face contact trace and is used to describe tooth face contact trace. This paper conducts a meshing performance analysis and quantitative evaluation of an aero spiral bevel gear pair. The result shows that, the actual and preset theoretical transmission error curves are basically in coincidence and the tooth face contact trace meets the requirements. This quantitative evaluation method lays a foundation for analyzing the relationship between transmission error curve and tooth face contact trace and for analyzing the installation error sensitivity.

Abstract: A method—characteristic parameters analysis (CPA) is put forward, which is used for quantitative analysis of contact pattern of spiral bevel gears with installation errors. For forming the tooth surface of spiral bevel gears, local synthesis is used. To imitate rolling test machine, the pinion drive torque is calculated under the indentation depth 0.00635mm. Driven by this torque, the size, shape, location and variation of contact pattern are obtained by loaded tooth contact analysis (LTCA). A pair of aviation spiral bevel gears was taken to quantitatively analyze the various contact patterns under different installation errors. The results indicate that the contact pattern is more sensitive to pinion axis installation error.

Abstract: Based on analyzing the mechanism of load sharing of power-split planetary gear trains, equivalent mesh errors are defined and introduced in this paper to take the deformations and manufacturing and assembling errors into account. The static equilibrium equation of planetary gear trains is established. Then the load sharing coefficients of a power-split planetary gear system are calculated. The results indicate that the load sharing of power input stage is worse than that of the power output stage in the power-split planetary gear system.

Abstract: The authors propose an optimization method based on local synthesis to fulfill the expected contact path (ECP) at mean contact point (M) of spiral bevel gears. The method is a combination of local synthesis, tooth contact analysis (TCA) and application of optimization. Machine-tool settings based on local synthesis are found and contact path (CP) on tooth surface is formed. TCA extracts the information from CP and transforms it to a projected CP (PCP) by rotation in a plane across gear axis. An objective function is established by contrasting ECP to PCP. A program in Matlab language is developed for the simulation of objective function optimization. A spiral bevel gear drive in aviation accessory gear box is used to prove the feasibility of the proposed method. It shows that the method is effective and does not affect transmission errors very much for the realization of ECP.

Abstract: An optimization approach for manufacture parameter design of the SGM spiral bevel gears with modified tooth geometry is proposed. The approach is accomplished by application of local synthesis, tooth contact analysis (TCA) and dual-objective optimization of transmission error function. A computer program to obtain a set of manufacture parameters based on the proposed theory is developed and illustrated with an example. The proposed method provides a set of machine-tool settings for pinion NC-grinding which ensures: (i) a localized bearing contact pattern less sensitive to misalignments, (ii) a parabolic transmission error function to reduce vibration and noise in mesh.