Preload adjustment for ball screw drives by means of passive mechanics

滚珠丝杠传动是机床中用于提供特定进给运动的机械元件。在这个项目中应用的进给传动的静态和动态行为的相关特性是承载能力，精度和刚度。滚珠丝杠传动的一个基本设计是采用预紧双螺母。然而，预载荷的强度是相互矛盾的目标之间的折衷，而且，它会随着时间的推移而降低。用于预紧力调节的主动执行器结构复杂，对运行特性有不利影响。在提出的研究项目中，应开发预紧力自适应调整的新概念。该方法基于被动机械元件，并通过仿真和实验方法进行了验证。初步研究证明了使用弹簧机构的可行性，弹簧机构会影响螺帽的节距偏移。其结果是根据最大轴向载荷调整预紧力。

Ball screw drives are mechanical elements used in machine tools to provide specified feed motion. Relevant characteristics for static and dynamical behavior of the applied feed drive in this project are load capacity, precision and stiffness. One essential design of the ball screw drive is the implemented preloaded double nut. The intensity of the preload, however, is a compromise between contradicting objectives and, furthermore, it decreases over time. Active actuators for adjustment of the preload are complex and have negative influence on the operation characteristics. In the proposed research project, a novel concept for a load-adaptive adjustment of the preload shall be developed. The approach is based on passive mechanical elements and is validated via simulative and experimental methods. Preliminary studies demonstrated the feasibility of using a spring mechanism, which affects the pitch offset of the nuts. The consequence is the adjustment of the preload based on the maximum axial load.