Magnetic Torque Compensating Methods for Cam Indexing Devices

In automatic production processes, cam indexing devices are frequently utilized to transport workpieces intermittently to the appointed manufacturing positions. However, because of alternating working forces and rotational inertia, indexing devices tend to generate vibration during each positioning process, which retards working speed and degrades positioning accuracy. To minimize positioning vibration, we developed a magnetic compensation concept and diverse devices based on the concept. A magnetic torque compensator basically consists of a magnetic loop with field generator and soft-magnetic elements. The soft-magnetic elements are designed to generate relative motion to each other to realize variable distribution of magnetic field and induce a compensation torque to suppress the positioning vibration. In addition to our experimental research, we investigated analytically the influential parameters of the compensating torque and their relationships by using the equivalent magnetic circuit method and the finite-element method. We found that modifications of magnetic arrangement or geometric parameters of functional elements lead to different characteristics of the magnetic torque curve. On the basis of the verified function and parameters of the magnetic torque compensator, we built some configurations to synthesize the compensating torque needed for countering vibration