Abstract This article presents a method for evaluating the torque output of orbit type displacement machines. Orbit machines are commonly used as hydraulic motors, for applications involving low speed and high torque output. The evaluation of the actual shaft torque as well as the hydro-mechanical efficiency in positive displacement machines is a topic that still presents challenges related to the evaluation of the torque losses associated with the functioning of the unit. This paper proposes a method of evaluating the torque efficiency starting from the evaluation of the instantaneous pressurization of each displacement chamber through a lumped parameter approach. From the instantaneous pressure in each chamber of the orbit motor, the contact forces normal to the rotor profiles are evaluated using a contact mechanics formulation accounting for the energy dissipation. The proposed algorithm computes the friction losses at the contact points to evaluate the net torque output of the orbit motor. Besides accounting for the frictional losses, the main elements of novelty of this approach also include the evaluation of the component deformation, instead of making rigid body assumptions. Experiments are performed on a set of reference orbit motor units to evaluate the torque output at different operating conditions. A good agreement between the simulated output torque and the one measured from experiments was observed, in terms of both instantaneous and mean values. The corresponding comparison of mechanical efficiency map is also presented. This shows the potential of the proposed method, which can potentially be extended to other types of gear machines, to evaluate the net shaft torque.

中文翻译：

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一种考虑变形效应和摩擦损失的液压轨道马达扭矩效率评估方法

摘要 本文提出了一种评估轨道式位移机扭矩输出的方法。Orbit 机器通常用作液压马达，用于涉及低速和高扭矩输出的应用。容积式机器中实际轴扭矩和液压机械效率的评估是一个仍然存在与评估与单元功能相关的扭矩损失相关的挑战的主题。本文提出了一种评估扭矩效率的方法，从评估每个排量室的瞬时增压开始，通过集中参数方法。从轨道马达各腔室的瞬时压力，使用考虑能量耗散的接触力学公式来评估垂直于转子轮廓的接触力。所提出的算法计算接触点处的摩擦损失，以评估轨道电机的净扭矩输出。除了考虑摩擦损失外，这种方法的主要新颖之处还包括对部件变形的评估，而不是进行刚体假设。在一组参考轨道电机单元上进行实验，以评估不同操作条件下的扭矩输出。在瞬时值和平均值方面，观察到模拟输出扭矩与实验测量的扭矩之间具有良好的一致性。还给出了机械效率图的相应比较。