| 摘要 |
<p>PURPOSE:To prevent the lowering of responsiveness of a hydraulic rolling reduction device caused by the length of a pipeline, by providing a braking means having a throttle at its inlet on the way of a main pipeline connecting a servovalve and a rolling reduction jack, in a hydraulic rolling reduction device for controlling the sheet thickness in a rolling mill. CONSTITUTION:A hydraulic rolling reduction device receives a command of the sheet thickness and a position signal of a ram 4 of a rolling reduction jack to compare them, and outputs the obtained error signal to a servovalve 7 after amplifying it by an amplifier. The servovalve 7 serves to position the ram 4 either by sending a pressurized oil corresponding to the signal to a pipeline 9 through an original pressure pipeline 11 or by relieving the oil to an oil returning pipeline 12. In this case, a chamber 20 having a capacity VC is connected to the point on the way of pipe line 9 having a crosssectional area SP through a throttle 21 haing a throttling area SB. And when the ratio of the capacity VC to the capacity VP(=SBl) of pipeline 9, i.e. VC/VP, and the ratio of throttling SB/SP, are selected respectively to be equal or less than respective prescribed values, the resonance of the pipeline 9 which causes the lowering of responsiveness is prevented, and also, a subsiding of the rolling reduction jack is decreased.</p> |
