Investigation of the operating behaviour of planetary roller screws with different number of threads of spindle and nut

为了将旋转运动转换为轴向运动，并将扭矩转换为进给力，可使用螺旋传动，如滚珠丝杠、滑动螺纹丝杠或行星滚柱丝杠(PRGT)。螺母和主轴的螺纹数相同的PRGT(Standard-PRGT)由于接触点数量多，具有高承载能力的特点。然而，可能的最低总体领先在几何和技术上都是有限的。因此，在许多应用中有利的高扭矩-力传动比是不可能的。对于螺母和主轴螺纹数不同的PRGT(Neu-PRGT)，在不损失承载能力的情况下，总导程可以减少到标准PRGT的八分之一。通过这种方式，可以实现更高的扭矩与力的传动比，从而可以使用较小的驱动电机，或者取消变速器。此外，还可以实现例如用于夹紧装置的自约束设计。由于这些特性，Neu-PRGT在许多应用中提供了滑动螺丝和液压执行器的替代方案。然而，Neu-PRGT的总导程取决于零部件中的运动条件和接触点上的力。与其他螺杆传动不同，传动性能取决于每个接触点的条件。整个研究项目的目标是对Neu-PRGT的传动行为进行数学描述和实验研究。在第一个研究阶段，考虑了单个接触点的行为，开发了描述PRGT运动比和PRGT传动行为的基本计算算法。标准PRGT和Neu-PRGT也进行了实验测试。对计算模型的验证表明了进一步研究的需要。在二期工程阶段，将建立输电行为的总体模型。为此目的，已开发的用于计算接触点行为的运动学关系和方法通过整个组件的内部相互关系以及与所产生的变量的相互作用来扩展。进一步的实验被用来研究Neu-PRGT的行为，以验证和优化假设和关联。

For the conversion of rotational movements into axial movements and of torques into feed forces, screw drives, such as ball screw drives, sliding thread screws or planetary roller screws (PRGT) are used. PRGT with the same thread number of nut and spindle (Standard-PRGT) are characterized by their high load capacity due to a high number of contact points. The minimum possible overall lead, however, is geometrically and technically limited. Therefore, a high torque to force transmission ratio, as would be advantageous in many applications, is not possible. For PRGT with different thread number of the nut and spindle (Neu-PRGT), the overall lead can be reduced to one-eighth of that of a Standard-PRGT without loss of load capacity. In this way, higher torque to force transmission ratios are possible, which allow for the use of smaller drive motors, or the elimination of transmissions. Also, a self-restraining design, e.g. for use in clamping devices, can be achieved. As a result of these properties, Neu-PRGT offer an alternative to sliding thread screws and hydraulic actuators in many applications. However, the overall lead of Neu-PRGT is dependent on the kinematic conditions in the component and the forces acting in the contact points. The transmission behavior, unlike other screw drives, depends on the conditions in each contact point. The aim of the overall research project is to mathematically describe the transmission behavior of Neu-PRGT and to investigate it experimentally.In the first research period, basic calculation algorithms were developed for the description of the kinematic ratios of PRGT and for the transmission behavior of PRGT, considering the behavior of a single contact point. Standard- and Neu-PRGT were also tested experimentally. The validation of the calculation models showed further research requirements.In the second project phase an overall model of the transmission behavior is to be created. The already developed kinematic relationships and methods for the calculation of the contact point behavior are expanded for this purpose by the internal interrelations of the whole component and the interactions with resulting variables. Further experiments to investigate the behavior of Neu-PRGT are used to validate and optimize the assumptions and correlations.