| 摘要 |
<p>PURPOSE:To remove hysteresis owing to the packing resistance of oil hydraulic jacks and to improve the responsiveness of the oil hydraulic screw down device of rolling mills by incorporating the construction wherein two sets of oil hydraulic jacks are superposed for the oil hydraulic jack in said device. CONSTITUTION:The oil hydraulic jack of a screw down device is made into the construction wherein an oil hydraulic jack 13 consisting of an oil hydraulic cylinder 1 and a ram 2 and an oil hydraulic jack 14 consisting of an oil hydraulic cylinder 4 and a ram 5 are superposed in two steps into one body. The jack 13 controls ordinary screw down and the jack 14 is used to apply dither to the jack 13. The oils in the cylinders of the jacks 13 and 14 are conducted to an oil hydraulic cylinder 8 for dither, and the piston thereof can be changed periodically of its position with an eccentric shaft 9 and a driving motor 10. It is possible to apply the dither to the oil hydraulic jacks without giving any change in the roll gap of the rolling mill, the hysteresis by the resistance of packings 3, 6 is removed effectively, the responsiveness of the screw down device is improved and the AGC of high accuracy is made possible.</p> |
