Development of servo motor driven workpiece gripping device

In promoting automation of workpiece delivery of NC lathe, workpiece gripping devices which are fitted to the tool fitting part of the tool turret unit have been suggested. For opening/closing devices of these workpiece gripping devices, motors, cylinders, and springs were used as conventional driving sources. However, using electric motors and cylinders as driving sources have problems caused by complication of turret structure. On the other hand, using springs have problems about poor versatility of workpieces that the workpiece gripping device can handle. Therefore, we focused on the fact that the tool driving shaft built in the tool turret is driven by servo motors and we developed a servo motor driven workpiece gripping device. In this paper, we will introduce the structure of the developed workpiece gripping device, how to grip and deliver workpieces, setting gripping force of the gripping device, and specific functions due to servo motor driving.