F1 Steering Rack, a closer look

[Stu]

Excellent study, incredibly interesting. Do you know what pressure it was designed to be operating at?

[Brian.G]

Excellent study, incredibly interesting. Do you know what pressure it was designed to be operating at?

Stu, the last two images in my first post - the ones from Moog - mention the valve can handle upto 4000psi,

Brian,

[Stu]

Excellent study, incredibly interesting. Do you know what pressure it was designed to be operating at?

Stu, the last two images in my first post - the ones from Moog - mention the valve can handle upto 4000psi,

Brian,

Thank you Brian, I didn’t see that. Return line pressure is quite high too (145psi), interesting that it gives a flow rate with 70 bar pressure drop across the valve.

[Tim.Wright]

Excellent study, incredibly interesting. Do you know what pressure it was designed to be operating at?

Stu, the last two images in my first post - the ones from Moog - mention the valve can handle upto 4000psi,

Brian,

Did you measure the effective piston area?

[Brian.G]

Tim, I didn't but I must.

Brian,

[PlatinumZealot]

The system still results in motion loss between steering wheel and rack. How much motion loss will always be a function of spool valve amplification factor.

The motion loss as the pinion centre shifts seems to be the analog to the rotational slack in the road car power steering upper shaft and pinion. It should a tiny fraction a mm I guess so that the system can sense the motion.

Do you think that because of the big tyre walls and relatively low pressures, and lighter in F1 that this slack does not as noticeable as in a heavy road car with stiff sidewalls?

[gruntguru]

The system still results in motion loss between steering wheel and rack. How much motion loss will always be a function of spool valve amplification factor.

The motion loss as the pinion centre shifts seems to be the analog to the rotational slack in the road car power steering upper shaft and pinion. It should a tiny fraction a mm I guess so that the system can sense the motion.

Do you think that because of the big tyre walls and relatively low pressures, and lighter in F1 that this slack does not as noticeable as in a heavy road car with stiff sidewalls?

Not sure. That factor will certainly change with the coming change in rim diameter.

As I said originally, the ratio of assistance to lost motion is entirely a function of the amplification factor chosen in the spool valve. Increasing that could reduce the motion loss but compromise other metrics - perhaps stability or "steering feel". It wouldn't be difficult to create a system with near-zero motion loss (measure and amplify steering column torque electronically) but the result would almost certainly lack feel and driver feedback.

[Greg Locock]

Citreon did that way back when, using hydraulic assist and no direct path to the steering wheel. Feedback such as it was by a spring, I think. DIRAVI. https://en.wikipedia.org/wiki/DIRAVI

[Tommy Cookers]

Citreon did that way back when, using hydraulic assist and no direct path to the steering wheel. Feedback such as it was by a spring, I think. DIRAVI. https://en.wikipedia.org/wiki/DIRAVI

this Citroen system or a similar might have enabled rear wheel steering (even replacing front wheel steering)
which could have had benefits with fwd (or awd) ...
or in F1 ???

but going OT is disrespectful to the OP's endeavours

[Brian.G]

Citreon did that way back when, using hydraulic assist and no direct path to the steering wheel. Feedback such as it was by a spring, I think. DIRAVI. https://en.wikipedia.org/wiki/DIRAVI

Thats one crazy system Greg...thanks for sharing, took me down a 2hr wormhole - finally understand how it works now Star to the author of the above wiki piece.

Brian,