Thursday, February 20, 2014
Parts of Power Steering
Power steering ers to steering assisted by a hydraulic pump, a pulley belt controlled by engine speed, a rotary valve device and steering gears. There are two types of power steering: rack-and-pinion steering and the recirculating-ball steering.
Steering Wheel
The steering wheel is a wheel controlled by the driver of the vehicle. When the driver turns the steering wheel, the wheels of the vehicle turn. The steering wheel is the user-controlled part of a power-steering system.
Rotary Valve
A rotary valve is a device that senses the forces applied on a steering wheel. It is part of a spool valve assembly. The rotary valve has a torsion bar. Force applied to a torsion bar causes it to twist and rotate the inside of the spool valve. The top of the torsion bar in the rotary valve connects to the steering wheel. Depending on the steering system, the bottom of the torsion bar connects to the worm gear or the pinion, which turns the wheels. When the spool valve turns, a port opens and allows steering fluid to flow to the appropriate lines. The lines connect to the power cylinder.
Rotary Vane Pump and Pulley
A rotary vane pump provides the hydraulic power for the power steering. The cars engine along with a belt and pulley run the pump. Retractable vanes inside a chamber of the pump spin and force hydraulic fluid to the outlet for the rotary valve. The pump runs faster when the engine is running faster. Higher engine speeds create higher pressure on the fluid flowing to the outlet. The pump also has a pressure-relief valve that opens if there is too much fluid pumping, such as with high engine speeds.
Steering Gear: Rack and Pinion
The steering gear turns the wheels. In a rack-and-pinion steering system, the pressurized fluid pushes on the power cylinder mounted on the rack. The resulting changes in pressure from the fluid moves the rack, making steering easier. The rack is a long metal piece with a flat side. On the flat side there are teeth cut into the edges. A steering shaft connects the steering wheel with the rack. A pinion gear on the end of the shaft connects with the teeth of the rack. On each end of the rack is a tie rod, which connects to the spindle of the wheels.
Steering Gear: Recirculating Ball
In a recirculating-ball system, steel balls roll between the steering shaft and the rack piston. With assistance from the hydraulic system, the rack piston moves up or down on a worm gear to turn the wheels.
Return Line
The return line directs the fluid from the power cylinder back to a reservoir on the pump.
No comments:
Post a Comment