Self-propelled work vehicle with forward speed regulation comprises heat engine rotating at constant speed driving transmission to driving wheel and hydraulic pump supplying hydraulic motor driving tool

摘要

The self-propelled work vehicle comprises a heat engine (M) which rotates at constant speed and drives a transmission with a part of the engine power to a driving wheel (R) with a variable transmission ratio, and a hydraulic pump (Pt) supplying a hydraulic motor (MT) driving a tool (T). There are hydraulic transformers (14) connected to the hydraulic motor supply comprising means for defining a pre-specified pressure threshold and able to change the hydraulic supply pressure variation law and to deliver a control output pressure (Ps) for supply pressures greater than the threshold. There are control means which receive the control output pressure which are connected to a means for varying the transmission ration so as to submit it to the control output pressure.