| 摘要 |
PCT No. PCT/EP95/02581 Sec. 371 Date Jan. 2, 1997 Sec. 102(e) Date Jan. 2, 1997 PCT Filed Jul. 4, 1995 PCT Pub. No. WO96/01383 PCT Pub. Date Jan. 18, 1996The invention relates to a drive system for a motor vehicle, in particular for a construction machine. A hydrostatic transmission unit comprising a variable displacement pump (25), a variable displacement motor (1) and a feed pump (26), is connected downstream of a diesel motor (24). In order to change gears in a powershiftable planetary transmission unit (2), gear-shift valves (34, 40) are provided. A brake (14) can be operated by a brake switching valve (30). The brake switching valve (30) is connected via line sections (33, 39) to the gearshift valves. When the brake switching valve (30) is in one switching position, a reservoir (37) is filled with hydraulic fluid. When in another switching position, a connection is made between the reservoir and a brake pressure chamber (20). During normal running of the machine, the reservoir is filled constantly with hydraulic fluid. When the brakes are operated, an adjustable residual pressure always acts on the brake. The brake is designed for dynamic deceleration. Deceleration always takes place in higher gear, thereby preventing unacceptably high values.
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