| 摘要 |
The invention relates to a control device (1) for a working fluid for operating a hydraulic drive (11) such as is used, in particular, for an elevator. Said control device (1) comprises a flow path (6) for directing a volume flow of the working fluid in a first and second direction, a first and second control valve (21, 22) for controlling the volume flow, a flow-measuring means (610) for detecting the volume flow, a pilot control means (3) with a first and second pilot valve (31, 32), and an electric actuating means (4) for interacting with a comparing means (52) for comparing the detected volume flow with a volume flow reference value which can be predefined by a reference value-setting means (51), and a controller (53) for generating an actuating signal for activating the first and second pilot valve (31, 32) via a coupling means (33) which can move to and fro between a first and second position for controlling the volume flow of the working fluid through the first and second control valve (21, 22), wherein in the first position of the coupling means (33) each pilot valve (31, 32) can be actuated and in the second position of the coupling means (33) only the first pilot valve (31) can be actuated by the electric actuating means (4). Furthermore, the invention relates to a hydraulic drive system (16) for an elevator having the control device (1) and to a method for retrofitting such a drive system. The invention is distinguished from conventional control devices in addition to simplifications in the design and operation and corresponding cost advantages as well, in particular, by a relatively low degree of expenditure on maintenance accompanied at the same time by an increased reliability. Said invention permits in a hydraulic drive system the automatic compensation of drive-side and output-side interference variables as well as load-induced fluctuations in the working fluid pressure in favor of a continuous output movement and load-independent starting without a delay, consequently an overall improvement in the starting quality in an elevator. |
