Im doing a essay on power steering, ive looked through loads of books and the internet but nothing really explains what a 'rotary vavle' is? Anyone know? Also does anyone know the 'future' of power steering?
Cheers if you can help!
2006-10-09 01:54:53 · 2 answers · asked by a10bvb 1 in Cars & Transportation ➔ Maintenance & Repairs
The previous question gave you some good information on the current hydraulic power steering systems but did not address your question about the future. More and more cars today are using electric power steering systems. These are ultimately simpler, since they do not require a power steering pump or use a separate closed fluid system. Power from the alternator is used to drive an electrically assisted power steering rack, which saves the weight and space consumed by a hydraulic power steering pump and the related fluid. It also is one less fluid to leak and cause environmental issues.
The future of power steering is almost certainly in electric power steering systems.
2006-10-09 03:07:47 · answer #1 · answered by pvreditor 7 · 2⤊ 0⤋
A power-steering system should assist the driver only when he is exerting force on the steering wheel (such as when starting a turn). When the driver is not exerting force (such as when driving in a straight line), the system shouldn't provide any assist. The device that senses the force on the steering wheel is called the rotary valve.
When the steering wheel is not being turned, both hydraulic lines provide the same amount of pressure to the steering gear. But if the spool valve is turned one way or the other, ports open up to provide high-pressure fluid to the appropriate line.
It turns out that this type of power-steering system is pretty inefficient. Let's take a look at some advances we'll see in coming years that will help improve efficiency.
The key to the rotary valve is a torsion bar. The torsion bar is a thin rod of metal that twists when torque is applied to it. The top of the bar is connected to the steering wheel, and the bottom of the bar is connected to the pinion or worm gear (which turns the wheels), so the amount of torque in the torsion bar is equal to the amount of torque the driver is using to turn the wheels. The more torque the driver uses to turn the wheels, the more the bar twists.
The input from the steering shaft forms the inner part of a spool-valve assembly. It also connects to the top end of the torsion bar. The bottom of the torsion bar connects to the outer part of the spool valve. The torsion bar also turns the output of the steering gear, connecting to either the pinion gear or the worm gear depending on which type of steering the car has.
As the bar twists, it rotates the inside of the spool valve relative to the outside. Since the inner part of the spool valve is also connected to the steering shaft (and therefore to the steering wheel), the amount of rotation between the inner and outer parts of the spool valve depends on how much torque the driver applies to the steering wheel.
2006-10-09 02:05:52 · answer #2 · answered by Anonymous · 2⤊ 0⤋