Continuous hydrostatic-mechanical branch power split transmission particularly for power vehicles

A hydrostatic/mechanical branch power split transmission for power vehicles comprising:

• an infinitely variable hydrostatic converter having a first hydrostatic unit of adjustable volume and a second hydrostatic unit;
• a power distribution device in which the driving power is split into a hydraulic and a mechanical branch and is summed again before the transmission output, whereby the infinitely variable converter is driven via a drive shaft and is drive connected to a distributing/summing transmission;
• at least one of a clutch element and a brake element which may be actuated selectively to provide a transmission point at which hydrostatic bridging takes place so that there is a purely mechanical transmission of power, said infinitely variable hydrostatic converter being relieved of load at such point so that no power is transferred,
• the arrangement being such that a first transmission fixed point with hydrostatic bridging is provided at the point where a hydrostatic shaft of the second hydrostatic unit is at rest, said infinitely variable hydrostatic converter being held in this state by actuating at least one of a clutch element and a brake element, and such that a second transmission fixed point is provided at the range limits of two neighboring gear-shift ranges, which point is determined by switching range clutches of the two neighboring ranges, said transmission being switchable alternatively between said fixed points;
• and
• a hydrostatic circuit comprising a brake pressure circuit and one of a pressure valve and a pressure regulator, said hydrostatic circuit being connected to said hydrostatic converter, the arrangement being such that the hydrostatic converter acts and can be controlled as a hydrostatic brake at a switched transmission fixed point by adjusting the infinitely variable hydrostatic converter.