Mechanical Servo Pump
| Number | Designation | Number | Designation |
| 1 | Power steering pump | 6 | Vanes |
| 2 | Housing | 7 | Outlet/Pressure duct |
| 3 | Inlet/Suction duct | 8 | Choke |
| 4 | Relief valve | 9 | Flow valve |
| 5 | Armature |
The mechanical servo pump is controlled by speed.
Design
The shaft in the pump housing is joined to the rotor (5).
The ten vanes (6) are located in the radial grooves on the rotor. Through the ducts in the rear and front control plates there are connections between the suction duct (3) and suction zones as well as the pressure duct (7) and the pump chamber's pressure zones.
Function
From the pressure chamber, the pressurized oil passes through the choke (8) to the pressure line and the integrated relief valve (4)/flow valve (9).
The rotation of the input shaft, and rotor (5) causes the vanes (6), through centrifugal force, to move radially on the groove on the secured outer ring. This motion is reinforced by the pressurized oil that flows from the pressure chamber via ducts to the inner surfaces of the vanes.
Ten independent pump cells are created between the ten vanes, which draw oil into the two half moon shaped pump chambers when the volume increases and force it out into the pressure chamber when the volume decreases.
The combined function of the choke (8) and flow valve (9) make it possible to achieve an increased flow level.
The upper limit of the oil pressure that the power steering mechanism is supplied with is determined by the relief valve (4).