variable axial piston pump of swashplate design for hydrostatic drives in closed circuit.The flow is proportional to the drive speed and displacement.The flow increases as the angle of the swashplate is adjusted from zero to its maximum value.Flow direction changes smoothly when the swashplate is moved through the neutral position.Two pressure-reliet valves are provided on the high pressure ports to protect the hydrostatic transmission (pump and motor) from overload.The high-pressure relief valves also function as boost valves.The integrated boost pump acts as a feed pump and control pressure supply.The maximum boost pressure is limited by a built-in boost pressure-reliet valve.