Oil Delivery

Oil Delivery









The rotation of the drive shaft and thus also the rotor causes the vane positioned in the rotor to be pressed in a radial direction on to the track of the fixed cam insert due to the centrifugal force arising. This is assisted by pressure oil which travels from the pressure chamber to the inner end faces of the vane via bores and grooves. Therefore 10 separate pump cells are formed between ten vanes which extract oil as the volume increases in the two sickle shaped pump chambers and eject it into the pressure chamber as the volume is reduced.

Since in each case two suction and pressure zones are opposite each other due to the shape of the cam insert, each of the ten pump cells delivers twice its volume per rotation of the drive shaft. In addition, the hydraulic radial forces acting on the rotor increase due to this dual arrangement of suction and pressure zones.

The combined flow control and pressure limiting valve of the pump results in a practically constant oil flow being delivered to the power steering over the entire engine speed range. The pressure limiting valve protects the servo system against overload. The opening pressure differs according to the vehicle and is up to 125 bar max.