What Is A Hydraulic Charge Pump

A hydraulic charge pump is a fixed displacement pump (typically a gear pump) that feeds the hydrostatic pump loop. A hydraulic charge pump is an integral part of the transmission circuit that provides many functions including the following;

Replenish hydraulic fluid lost from the transmission loop due to the internal leaking of the pumps and motors. The hydraulic charge pump makes up for all of these internal leakages.

Provides constant back pressure and lubrication of the hydrostatic pump and motors rotating group. Most manufacturers of these products require a back pressure of 222 – 300 psi for proper functioning.

Provides flow/pressure source for auxiliary functions such as hydraulic parking brakes and servo circuits. In addition, hydraulic charge pump can be used to supply pilot pressures.