Abstract
Advantages of planetary speed reducers are well known and due to their compact design and power density they are suitable for a wide range of applications. Efficiency is becoming more and more a main concern in the design of power transmissions and the demand for high efficiency gearboxes is continuously increasing. Moreover, in advanced applications that require a kinematic train with high positioning accuracy, low backlash and high rotational stiffness are also required. In any case data of efficiency, backlash and stiffness must be known in order to model the behaviour of a transmission system. For this reason a testing campaign have been conducted, in order to characterize these aspects for the low-backlash Tecnoingranaggi planetary speed reducers, a brand of the Bonfiglioli group. The test program have enabled a deeper knowledge of the functional behaviour of the gearboxes of this family providing useful data to validate models of efficiency.