Antriebseinrichtung für ein Kraftfahrzeug, insbesondere eine Baumaschine

摘要

The 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 to a diesel motor (24) downstream of it. In order to change gears in a power shift planetary transmission unit (2), gear shift valves (34, 40) are provided. A brake (14) can be operated by a brake switch valve (30). The brake switching valve (30) is connected via line sections (33, 39) to the gear shift 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, which is designed for dynamic deceleration. Deceleration always takes place in a higher gear, thereby preventing unacceptably high values.