Steering/ADS suspension system tandem pump, function - GF46.30-P-2200-01A
Oil delivery
The spring-loaded pistons (49c) undergo a lift motion due to the rotation of the cam (49a) on the drive shaft (30r). When the piston is travelling towards bottom dead center a vacuum occurs due to the increase in space in the piston chamber. This causes the oil to flow in through the cross bores in the piston which connects the cylinder chamber with the inlet side shortly before bottom dead center.
On the working stroke the filled cylinder chamber is sealed due to overlap of the bores shortly after bottom dead center. The oil is pushed out towards the pressure side via the spring-loaded outlet valves.
The constant oil flow at variable speed is achieved by the suction control. As the speed increases the opening time of the cross bores in the piston reduces so that the vacuum is not longer sufficient to completely fill the cylinder chamber in the short time interval. The reducing partial filling causes the volume flow and the required power to remain almost constant as speed increases.
Pressure limitation
The pressure of the radial-piston pump is limited by pressure relief valves in the control units of the connected systems.
An output and pressure test must therefore not be carried out directly at the radial-piston pump section of the tandem pump.