2019 Volume 60 Issue 702 Pages 189-194
Recent ultrahigh-tensile-strength steel sheets have become indispensable for improving fuel economy through their incorporation into skeletal parts of automobiles to reduce the weight. To enable the forming of ultrahigh-tensile-strength steel sheets, a high-performance upper cushion is indispensable. The developed high-performance frictional gas cushion device applies as cushion force by frictional force generated by sliding between metal parts of the shaft parts and the hole parts having interference. Frictional cushion force mechanism was added to the upper piston shaft portion of the gas cushion device. In this apparatus, in addition to the repulsive force (gas cushion force) generated by the gas when the piston is pushed into the cylinder, frictional force (frictional cushioning force) due to interference between the inner surface of the cylinder and the outer surface of the piston shaft can be obtained. Therefore, it is possible to obtain a higher cushioning force than that with the conventional gas cushioning apparatus, which generates cushioning force only by the repulsive force of the gas.
