Drawing tool for esp. seat pad frames for motor vehicles has bottom die with inserts of silicon nitride or zircon oxide in parts subjected to wear

摘要

The drawing tool has upper die, holding-down device, and bottom die, to draw bowl-shaped parts with narrow edge radii. The esp. bottom die (1) slides over the plate to be drawn in the sections with small edge radii (R), and has ceramic inserts (8',9') of silicon nitride (Si3N4), or of zircon oxide (ZrO2), or completely consists of such a ceramic material. The inserts are divided into segments, and fastened by fastening screws (12), which extend at right angles to the drawing direction. In a drawing tool to form cylindrical collars near bores, the upper die consists at least partially of silicon nitride or zircon oxide.