Flexible drive shafts

[Triumphman]

Hi, has anyone got any experience of these?
I've got an application on the steering of a vehicle where the route between the bottom of the steering column to the output on the steering rack is awkward. They're not in line or on a similar plane and there is an obstacle in the way.
It would probably take a 3 piece shaft with ujs in between to couple the two, so not ideal.
The rpm is almost non existent as it's just for steering.
I wondered if one of these flexible drive shafts is an option?
Where to get one? How much to pay?

 

[johnik]

Really you need UJ,s with the shaft running through a bearing,i have used rose joints for bearings in the past.

 

[MrFluffy]

Not sure that it would even be legal if for road use, the rules on construction in that area are pretty strict on what you can do even using conventional parts. I seem to remember your not allowed to weld two sections together to get different spline ends for the link for e.g.
If its for a offroad only vehicle, go for it. Jcb's for one have a hydraulic steering system with no physical link between the wheel and steering cylinder. Provided your flexible drive is stiff enough in the drive plane it can't be any worse a scenario than that.

 

[Triumphman]

Not for road use, should have said that

 

[MrFluffy]

Don't know where you would source one, but my boring bar has a drive cable which the core cable is about 25mm in diameter and transmits 3hp. Seen large driveshaft cables in industrial applications too, so somewhere to start looking.
You need to specify you want a bidirectional cable not a uni one so your not winding and then unwinding the cable tension on drive direction change.

 

[normspanners]

Go to fork lift places they use hydraulic too, orbital control valves they are called will work with no power assist but are better with hydrauliuc pump which could be electric like an astra one ??

 

[normspanners]

I seem to remember your not allowed to weld two sections together to get different spline ends for the link for e.g.

that is how QR wheel bosses /ends are fitted to columbs ?
http://go-race.co.uk/shop/458274994...-quick-release-steering-hub---weld-on/7229497

 

[MrFluffy]

It is, its also how the yokes are welded onto the linkages in the first place and how the stock steering boss is attached the column but then the parts in some vehicles will potentially undergo post-weld heat treatment to re-apply properties of toughness etc or be made by forging to get the grain structure orientated correctly for the load on it. But welding two foriegn halves of a linkage together to get different spline standards without some extra strength being put back in or consideration for heat treat is a bodge really, to do it right a linkage piece if it needs different splining should have a yoke changed for one with the correct spline and then heat treated post weld, or a new spline cut into it, and thats what the regs are trying to stop.

MOT Inspection Manual - Section 2.2 – Steering System
Repairs by welding or evidence of excessive heat having been applied to steering components
and structural members have long been Reasons for Rejection. However, this is updated to
include any inappropriate repair or modification to a steering component.
Guidance on what constitutes an ‘inappropriate repair or modification’ has been added to the
Introduction Section, where it states:
“Repairs and modifications to vehicles must be assessed on their merits, taking account of
the nature and function of the component.
The main criterion to be used when assessing repairs is whether the repair is obviously
likely to adversely affect the roadworthiness of the vehicle. In respect of modifications, the
main criterion should be whether the modification has seriously weakened the component.”
Before the days of MOT Computerisation, many testers incorrectly failed steering and suspension
ba

I'm just quoting that as a example of things someone thinking of modifying a steering connection then taking it for a test after might take into consideration/may fall foul of. It doesnt apply in this case as its a offroad vehicle.

Looking at and discussing in depth at the moment because Im considering a hydraulic power steering conversion on a non power steered vehicle, and whatever I have to do will have to stand close scruity as its obviously been changed from original. I don't have heat treatment facilities in my workshop so if I take that route the part will have to go out for that, but I can respline things inhouse.

 

[Ton-up]

There were a couple of 60's/70's American cars that had a flexible shaft steering. Don't know wht your application is, but what about an off-set drive? Basically two sprockets and a chain in a housing which will off-set the shafts. I think they do different off-sets.
Simple to make one yourself.

http://www.speedwaymotors.com/Steer-Clear-Steering-Box-Drop-Brushed-Finish,6254.html

 

[ford34/2]

Borgeson and many other manufacturers would be able to sort it out.
have a look at about page 25, and take note of Phasing joints.

https://borgeson.com/Images/2013_Catalog.pdf

Stan

 

[normspanners]

ford pinto flexible link

john deer flex shaft