Abstract: Rack and pinion jacking system is an important load transmission and bearing device for jack-up platform. Contact stress generated by the meshing between rack and pinion, together with vibration caused by the stiffness excitation, are two important factors that affect the transmission performance and service life of the jacking system, so it has great engineering significance to improve its dynamic performance by optimized structural design and simulation analysis. Through setting appropriate phase differences between the pinions, the staggering tooth meshing of pinion is realized and the bearing performance and dynamic characteristics of the mechanism are improved effectively. In terms of staggered tooth meshing optimization scheme, the finite-element analysis for staggered tooth meshing process and normal meshing process of rack and pinion are done, and the improvements of staggered tooth meshing optimization to the transmission mechanism strength and time-varying stiffness are verified. The modal characteristics, stationarity and synchronicity of the rack and pinion system during meshing process and the uniformity of pinions’ load distribution are also compared. The results show that the contact stress and bending stress of the rack and pinion pinions with staggering tooth are smaller, and gears’ stiffness step value is significantly reduced. At the same time, the rack and pinion pinions with staggering tooth have good performances in the dynamic stationarity and synchronicity and the loads distribution. Pinion’ staggering tooth meshing can improve the bearing capacity and motion performance effectively, which is important for optimization design of jack-up’s jacking system.

Key words: jack-up platform;rack and pinion;pinion with staggering tooth;strength analysis;mesh stiffness