Linde Hydraulics Gmbh & Co. Kg

Linde Material Handling Gmbh

Linda Hydraulics Gmbh & Co. Kg

Martin Steigerwald

Lukas Krittian

Alfred Langen

Martin Oberhausser

Burkhard Sturmer

Matthias Baumann

Martin Oberhäußer

Dr Alfred Langen

Thomas Dierkes

A drive train () includes an internal combustion engine () and working hydraulics () having at least one hydraulic pump (). When operated as a pump, the hydraulic pump () sucks hydraulic fluid from a tank () and delivers into a delivery line () that leads to the working hydraulics (). When operated as a motor, the hydraulic pump () is supplied with hydraulic fluid from a hydraulic accumulator (). The drive train () has a charge pump () to supply a charging circuit (). The charge pump (), when operated as a pump, sucks hydraulic fluid out of the tank () and delivers into a charge pressure line () that leads to a charging circuit (), and the charge pump () when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator ().

Drive train of a vehicle

A variable displacement hydrostatic power unit () is in a drive connection with an internal combustion engine (). When operated as a pump, the power unit () delivers hydraulic fluid to at least one consumer (V). When operated as a motor, the power unit () is a hydraulic starter for the internal combustion engine () and is supplied with hydraulic fluid from a hydraulic accumulator (). The displacement volume of the power unit () is set by a displacement volume control device () actuated by a positioning device (). The displacement volume control device () is displaced into a position with maximum displacement volume by a corresponding actuation of the positioning device () chronologically prior to the shutoff of the internal combustion engine (). A securing device () holds the displacement volume control device () in the maximum displacement volume position when the internal combustion engine () is shut off.

Hydrostatic power unit as hydraulic starter of an internal combustion engine

A drive train () has an internal combustion engine (), a traction drive (), and working hydraulics () having at least one hydraulic pump (). A connecting line () leads to a hydraulic accumulator () and is connected to a delivery line () of the hydraulic pump () that leads to the working hydraulics (). A shutoff valve () is located in the connecting line (). The shutoff valve () is a check valve () that opens automatically and as a function of the pressure to allow a flow to the hydraulic accumulator (). A pressure relief valve () is operatively associated with the connecting line () between the shutoff valve () and the hydraulic accumulator ().

A variable displacement hydrostatic power unit () is connected with an internal combustion engine (). The power unit () operates as a pump to deliver hydraulic fluid to at least one consumer (V) and operates as a motor as a hydraulic starter for the internal combustion engine (). Hydraulic fluid from a hydraulic accumulator () is supplied to the power unit () operated as a motor. The power unit () includes a spring device () which, when the internal combustion engine () is shut off, actuates a displacement volume control device () into a position with the maximum displacement volume. When the power unit () is actuated with hydraulic fluid from the hydraulic accumulator (), the internal combustion engine () is immediately started by the power unit () without the need for an immediately preceding adjustment of the displacement volume control device () of the power unit ().

Hydrostatic power unit to start an internal combustion engine

A hydrostatic pump () with a variable displacement volume can be operated in a closed circuit and is driven by a drive engine (), in particular by an internal combustion engine. To control the displacement of the pump (), a control device () is provided which can be actuated as a function of the speed-dependent control pressure which is a function of the speed of the drive engine (). To improve the control characteristics of the pump, a switchover device () is provided, by which the pump () can be switched between a speed-dependent displacement control by the speed-dependent control pressure and a volume flow-dependent delivery control, in which the control device () of the pump () can be controlled as a function of the actuation of an actuator mechanism ().

Hydrostatic pump

A hydrostatic pump () has a mechanical displacement volume control with a mechanical control element (), which for generation of an actuator pressure that acts on a positioning piston () which is functionally connected with a displacement setting device (), has a position-controlled control valve () functionally connected with a control lever () and with the displacement setting device () of the pump (). A pump with a mechanical displacement volume control with a pressure limiting function can be accomplished by mechanically decoupling the control lever () from the displacement setting device () whereby a pressure cutoff function is provided, with which, by respective pilot valves (), a pressure signal can be generated from a delivery line () of the pump (), which signal is transmitted via the control valve () to the positioning piston () and counteracts the control pressure.

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Glattbach, Germany

Martin Steigerwald