Poclain Hydraulics Industrie

Pierre-Louis Houillon

Gilles G Lemaire

André Prigent

Julien Lambey

Christophe Gouzou

Gery Depierre

Claude Didierjean

According to the method, transmission apparatus of a vehicle, the apparatus comprising a drive engine (), a mechanical transmission () connected to the drive engine, and a hydraulic transmission () having a pump () and n hydraulic motors (A,B), where n is greater than or equal to 1, the pump being suitable for being driven by the drive engine for feeding fluid to the hydraulic motors. The method consists in performing a 'low-speed' assistance stage, during which, when the vehicle is driven by the mechanical transmission, the method consists in establishing a setpoint pressure for the pressure difference between the feed and the discharge of each of the hydraulic motors, in feeding the hydraulic motors by the pump, in detecting the pressure difference between the feed and the discharge (A,B) of each of the hydraulic motors (A,B), and in adjusting the delivery rate of the pump so that said pressure difference is substantially equal to said setpoint pressure.

Method for hydraulically assisting the drive of a vehicle at low-speed

Hydraulic transmission apparatus () including a pump () having a variable cylinder capacity and feeding one or more hydraulic motors (A,B), and a control unit (). In the apparatus, the feed and discharge orifices of the motors are arranged in such a manner that, when the pressures at said orifices are equal, the outlet torque from the motors is zero. To make the apparatus inactive, without physically bypassing the motors, the control unit is suitable for operating the apparatus in a 'torque-free' mode by regulating the cylinder capacity of the pump in such a manner that the pressures at said feed and discharge orifices remain substantially equal.

Hydraulic transmission device

The present invention relates to a double hydraulic machine () comprising two elementary machines (M, M) each having two orifices, the double hydraulic machine () comprising a distribution valve () suitable for, in a first configuration (C), feeding both elementary machines (M, M) in parallel, and in a second configuration (C), producing a short circuit of one of the elementary machines (M). The invention also relates to a system for driving a vehicle comprising such a hydraulic machine () for driving the vehicle into motion.

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Verberie, France

Pierre-Louis Houillon