Chapter 25 Steering Systems 513
Figure 25-28 shows vane operation in
another vane-type pump. Notice that some fl uid,
which is under pressure, is admitted behind the
vane ends to force them outward to contact the
pump. An exploded view of a roller-vane pump
is shown in Figure 25-29. An exploded view of a
gear pump is shown in Figure 25-30.
Power Steering Hoses and Tubing
The power steering gear and pump are con-
nected by high-pressure hoses and steel tubing.
These hoses are able to withstand very high
Oil
pressure
behind
vanes
Crossover
passage
Pump ring
Pump rotor
Pump vanes
Crossover
passage
Dowel
pin hole
Dowel pin hole
Figure 25-28.
Vane-type power steering pump.
Goodheart-Willcox Publisher
Bolt
Remote reservoir
inlet tube
Seal
Venturi
Seal
Drive
shaft
Bolt
Pump
housing
Locating pin
End
plate
Port
plate
Cam
Orifice
Control valve
Housing cover
Vane carrier
Roller vane
Seals
Valve
Figure 25-29.
Exploded view of a roller-vane power steering pump. This
unit uses a remote reservoir (not shown).
To gearbox
Pressure regulator/
relief valve
From reservoir
Driving
gear
Driven
gear
O-ring seal
Pump gear
chamber
Seal
Pump body
End plate
Direction of
pump rotation
Drive
pulley
Ribbed drive belt
Flow direction
Figure 25-30.
Exploded view of a gear-type power steering pump. Note the pressure regulator/relief valve which maintains a pump
output fl uid pressure of 1135 psi–1280 psi (8000 kPa–9000 kPa). This pump is made from aluminum to help reduce
weight and aid in cooling. Follow the fl ow direction arrows.
Honda