V90 L6-2.9L VIN 96 B6304S (1998)
Power Steering Pump: Description and Operation
Power Steering Pump
DESIGN
The power steering pump is of the vane type and mounted in a bracket on the engine. The pump is belt driven from the crankshaft at the same
engine speed (RPM).
The pump is joined to the steering gear via a pressure oil hose and by a return oil hose.
FUNCTION
Illustration A displays oil flow with the steering gear in the neutral position. Illustration B displays oil flow with steering gear under load. The
lighter gray area illustrates the low pressure servo oil, while the darker gray indicates high pressure servo oil.
The pump rotor has 10 loose laminated vanes and rotates in a ring shaped distancer. The laminated vanes are pressed against the walls of the
distancer by centrifugal force and oil pressure.
The area of inside the distancer is oval, see illustration A. Because of this the space between the rotor, distancer wall and two of the vanes changes
when the rotor rotates.
When a pair of vanes move from the suction side to the pressure side the space between them increases and oil is sucked in.
The vanes move onto the pressure side. The gap between the vanes decreases at the same time the pressure increases and the oil is forced out into
the delivery pipe.
There are two suction and pressure channels which gives the pump double capacity.
