Bosch Rexroth Ag

Brueninghaus Hydromatik Gmbh

Mannesmann Rexroth Ag

Chris Shrive

Heinz-Gerhard Essig

Sinclair Upton Cunningham

Graham Perry

A hydrostatic power train includes a hydraulic pump, which is connected, via a first main pipe and a second main pipe, to a first hydromotor unit driving a front axle and to a second hydromotor unit driving a rear axle. The first and second hydromotor units can be adjusted in terms of their displacement via a first and second variation device. A direction of travel is defined as forward movement (F) or reverse movement (R) by a position of an operating lever. The first and the second variation devices are controlled by a control valve which takes up a first control position upon a forward movement (F) determined by the position of the operating ever and which takes up a second control position upon reverse movement (R) determined by the position of the operating lever and which takes up a second control position upon reverse movement (R) determined by the operating lever. In the first control position, the first variation device is controlled such that the first motor unit is adjusted for a smaller displacement and, in the second control position; the second variation device is controlled such that the second motor unit is adjusted for a smaller displacement.

Control for a hydrostatic power train

A hydraulic control circuit for a radial piston engine with two speeds. The changeover between the speeds takes place through the alteration of the absorption volume, the delivery side being connected to the discharge side with a bypass connection by a valve arrangement for a selected number of engine pistons. The control circuit provides a space-saving way of ensuring that the changeover between speeds occurs smoothly and in such a manner to preserve the individual components as far as possible. To this end, at least one intermediate switching position, in which the delivery side is throttled to the discharge side, i.e. connected by a diaphragm-type arrangement, is provided in front of valve arrangement between the two end switching positions. The valve arrangement is preferably driven such that a valve body can be moved through the intermediate switching position at a controlled speed.

Hydraulic control circuit for a hydraulic engine with at least two speeds

A hydraulic radial piston engine has a lifting ring fixed to the casting, a rotor mounted opposite the lifting ring such that it is rotatable about an axis of rotation, multiple piston seats aligned radially in the rotor relative to the axis of rotation, and multiple pistons each displaceably mounted in a piston seat and which, over at least part of their length, have a non-circular guiding and sealing cross section that is coincident with a non-circular guiding and sealing cross section of the piston seats. Circularly cylindrical rollers are borne by the piston. With a given overall size, a greater swept volume per piston is possible and therefore a greater torque is produceable.

Hydraulic radial piston engine

What is disclosed is a radial piston machine having a plurality of radial pistons each guided in a respective cylinder space, wherein the cylinder spaces may be connected with supply and drain passages for pressure medium via control recesses. The opening cross-sections of the control recesses and of the supply and drain passages are provided with curved end face portions.

Radial piston engine

A hydrostatic vehicle drive (,) comprises a first hydropump (,) and a second hydropump (,) as well as a first hydromotor (,) and a second hydromotor (,). The hydromotors (,) each drive separate drive lines. During straight-ahead travel operation, the hydropumps (,) and the hydromotors (,) are coupled to one another in a single, closed hydraulic circuit without crossed connections in such a manner that an input connection (,) of the first hydromotor (,) is connected to an output connection (,) of the first hydropump (,) and an input connection (,) of the second hydropump (,) is connected to an output connection (,) of the first hydromotor (,). An input connection (,) of the second hydromotor (,) is connected to an output connection (,) of the second hydropump (,), whilst an input connection (,) of the first hydropump (,) is connected to an output connection (,) of the second hydromotor (,).

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Dunfermline, United Kingdom

Chris Shrive