| 摘要 |
PCT No. PCT/EP94/01887 Sec. 371 Date Mar. 28, 1996 Sec. 102(e) Date Mar. 28, 1996 PCT Filed Jun. 9, 1994 PCT Pub. No. WO94/29619 PCT Pub. Date Dec. 22, 1994The invention relates to a hydrostatic propulsion drive having a drive motor, of variable speed, for a hydraulic machine of a hydraulic transmission, a setting device for the displacement volume of the hydraulic machine, a device for generating a setting pressure proportional to the speed of the drive motor in a setting pressure line, a pilot valve in the setting pressure line which is coupled with the setting device and-dependent upon its though-flow position within a through-flow adjustment range of effective follow-up into the closed position-controls the volume of a pressure medium supplied to the setting device, and in a through-flow end position beyond the effective follow-up acts upon the setting device with the speed-proportional setting pressure. In order to provide higher torques at lower vehicle rates of travel, a pressure medium line (44) for the pressure medium to be supplied to the setting device (4) in the case of effective pilot valve follow-up is connectable with a pressure independent of the speed of the drive motor via a switching device (6.1; 6.2; 6.3) to the setting pressure line (37, 43) upstream of the pilot valve (7), whereby the switching device (6.1; 6.2; 6.3) has a normal and a switched position, in the normal position connects the pressure medium line (44) with the setting pressure line (37, 43) and a blocks the action of the speed-proportional setting pressure upon the setting device (4), and in the switched position blocks the pressure medium line (44) and acts upon the setting device (4) with the speed-proportional setting pressure.
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