自升式平台齿轮齿条升降机构错齿优化动力学分析

Dynamic Performance Analysis of Jack-up Platform's Jacking System with Staggering Tooth

齿轮齿条升降机构是自升式平台的重要传动和承载装置,啮合产生的接触应力和由于刚度激励引发的振动是影响升降系统传动性能与使用寿命的重要因素,因此通过进行结构的优化设计和仿真分析提高传动机构动力学性能具有重要的工程意义。提出通过优化设置自升式海洋平台齿轮齿条升降机构小齿轮之间相位差的方式实现错齿啮合,从而实现有效提高机构承载能力和动力性能的目的。结合提出的错齿优化方案,对错齿前后齿轮齿条啮合过程进行动态接触有限元分析,并验证错齿优化对传动机构强度和时变刚度的改善效果,并对比分析齿轮齿条传动机构模态特性、运动平稳性和同步性以及小齿轮载荷分配均匀性等动力学行为。结果表明,错齿优化后齿轮齿条升降机构在动态啮合时能够产生更小的接触应力和弯曲应力,而且齿轮综合刚度的阶跃值有明显减少,与此同时在传动平稳性、同步性和载荷分配均匀性方面也具有良好表现。因此错齿优化可有效地提高齿轮齿条传动过程中的承载能力和运动性能,对改进齿轮齿条升降机构的设计具有参考价值。

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.