Power Steering Fluid Flow
Neutral Position - Straight Ahead
In the straight ahead position, power steering fluid flow from the pump (1) is directed into the cavity (A) of the inner valve assembly (2) and out through a number of drilled holes (B) in the outer sleeve (3). In this steering position, the inner valve allows power steering fluid to pass equally to both sides of the rack (4) piston (shown as static because no power steering fluid actually flows to and from the steering gear). The bypassed power steering fluid returns to the power steering fluid reservoir (5) through holes drilled in the longitudinal grooves of the inner valve. With an equal pressure applied to both sides of the rack piston, no power assistance is provided.
Turning Left
When turning to the left, relative motion between the inner rotating valve (1) and the outer sleeve (2) occurs, this blocks the fluid return cricuit and redirects the fliud to the right-hand side of the rack piston (3), at the same time the power steering fluid on the opposite side of the piston is directed to the return circuit, leading to the reservoir (3) and the pump (4). This action is slight at first, providing only a small amount of driver assistance, but becomes progressively greater with higher steering loads as the torsion bar in the rotary valve assembly allows the valve to rotate further.
Turning Right
When turning to the right, relative motion between the inner rotating valve (1) and the outer sleeve (2) occurs, this blocks the fluid return cricuit and redirects the fliud to the left-hand side of the rack piston (3), at the same time the power steering fluid on the opposite side of the piston is directed to the return circuit, leading to the reservoir (3) and the pump (4). This action is slight at first, providing only a small amount of driver assistance, but becomes progressively greater with higher steering loads as the torsion bar in the rotary valve assembly allows the valve to rotate further.