Progressive Die Design for Plate of Micro Planetary Gear Train Hui-Chi Chang and Hsin-Te Wang

Micro Planetary Gear Train (PGT) transfers the torque and high speed of micro motor into an effective output motion which greatly extends the application of micro driven device. Carrier of PGT is the key component to transfer the torque and reduction. Due to the trend of lighter, slicer, shorter, and smaller characteristics for work pieces, the small tolerance in conventional manufacturing machine is getting harder and harder. In micro PGT, the carrier is composed of sun gear, sun shaft, planet shaft, and plate. As the demand of dimensional tolerance in the plate of carrier, the procedure of assembly is considered. The high concentric tolerance (  5  m) of the four side holes respect to center hole (Pitch of Circular Diameter, PCD) in the plate is hardly to produce in conventional CNC lathe machine. So, this paper discussed the progressive die design for the plate to achieve the above demands in pilot mass production. First stage of forming process is punching the pilot hole. And, the following stages of forming process are including sizing, semi-piercing, piercing, shaving, and blanking etc. And, some idle stages are setting in the process for further modified stages. The top and bottom die sets are displayed and its corresponding assembly is also shown. Finally, the plate has produced in higher flatness and perpendicularity characteristics which effectively improved the precision of dimension and assembly of PGT.