Steering Gear: Description and Operation

The movement of the steering wheel is transferred to the pinion. The movement of the pinion is then transferred through the pinion teeth, which mesh with teeth on the rack, causing the rack to move. The power steering gear system has a rotary control valve which directs hydraulic fluid coming from the hydraulic pump to one side or the other side of the rack piston. The integral rack piston is attached to the rack. The rack piston converts hydraulic pressure to a linear force which moves the rack left or right. The force is then transmitted through the inner and outer tie rods to the steering knuckles, which turn the wheels. If hydraulic assist is not available, manual control is maintained; however, under these conditions, more steering effort is required. A vane-type pump provides hydraulic pressure for the system.