Outer Limits 4x4 Board

Hi guys

I need some help here. Has anyone had any experiance with these units?
I'm after an hydraulic torque amplifier for a project I am building, basicly its to steer a huge RC car.
I need to know how small you can get them? I plan to run it from an electric power steering pump from a toyota or holden astra.
The only ones I have found so far are these ones on ebay from the states.

http://cgi.ebay.com.au/Sauer-Danfoss-Hy ... 2c5274252e
http://cgi.ebay.com.au/Eaton-Char-Lynn- ... 2c527407e3
Unfortunately postage is the killer!

Would hydraulic shops in australia stock such a beast?

Cheers
Simon

I've only ever seen them on old Fowler tractor cranes. I doubt they make very small ones as there isn't much need. I mean unless you need a big one you could turn the wheel by hand without assistance.

Isn't it basically a power steering box? Sorry if this is a stupid question

Actually Chimpy - IMO your spot on.....

As you can play with the torsion bar in power steer boxes quite easily it wouldn't be that hard to adjust the assist ratio.

MightyMouse wrote:Actually Chimpy - IMO your spot on.....

As you can play with the torsion bar in power steer boxes quite easily it wouldn't be that hard to adjust the assist ratio.

Not really, this is a full hydro assist unit. As theres no mechanical linkage as an output from the unit, where a power steering box has the output shaft for the the pitman arm to spline onto to. This is what all earthmoving trucks etc use for steering.

I'm sure your correct nayto, i know sfa about these.

Still by the description of what he's wanting to do ( and i'm sort of reading between his lines ) a modded PS box would work.

I'm assuming he's going to use a RC servo as input and just want's more "gain" ?

Perhaps some more info required ?

Yep, thats about what I want.

No servo made comes close to having enough torque for what I want to do, these torque amplifiers look like what I'm after, but if I can mod a PS box for cheaper, I'm all for it! It needs to be very easy to turn (from the input end) for the normal servos to control.
Also the torque amplifier or PS box only need two main parts whereas the hydraulic sering units require three main parts.

Cheers fellas

I've ground down the torsion bars in PS boxes to lower the steering effort for disabled drivers.

To the disabled they felt like normal effort - to me a touch of the little finger was all the effort that was required - bit scary if you weren't on the ball

Well worth a play IMO and very cheap.

Build up thread of the RC car please

Thought aboutthese? 2" per second so assuming ~6" travel required, would go lock to lock in 3 seconds. Much easier to control electronically and lighter.

in particular this



I am thinking along the lines of mounting it on the back/top of the front diff with backwards facing high steer tabs to the hubs. Just need to switch 3-4 amps PWM to vary speed and change polarity to go the other way (= easy off the shelf electronics from an RC reciever)

vanbox wrote:Build up thread of the RC car please

lol. Kawazaki Z250 motor, home made chassis, go kart axle and steering and a 70L esky!

DAMKIA wrote:Thought about these? 2" per second so assuming ~6" travel required, would go lock to lock in 3 seconds. Much easier to control electronically and lighter.

in particular this

Trouble is I don't know enough about the electronics required to make it self centering Those units would be great otherwise!

Simonc3 wrote:

vanbox wrote:Build up thread of the RC car please

lol. Kawazaki Z250 motor, home made chassis, go kart axle and steering and a 70L esky!

DAMKIA wrote:Thought about these? 2" per second so assuming ~6" travel required, would go lock to lock in 3 seconds. Much easier to control electronically and lighter.

in particular this

Trouble is I don't know enough about the electronics required to make it self centering Those units would be great otherwise!

That would all be to do with your RX/TX configuration. Normal joystic control would make it self centre. Talk to an RC model shop or forum, should be VERY easy as this is exactly how normal servos work...

Simonc3 wrote:Yep, thats about what I want.

No servo made comes close to having enough torque for what I want to do, these torque amplifiers look like what I'm after, but if I can mod a PS box for cheaper, I'm all for it! It needs to be very easy to turn (from the input end) for the normal servos to control.
Also the torque amplifier or PS box only need two main parts whereas the hydraulic sering units require three main parts.

Cheers fellas

easy and cheap to do! just not the way you are thinking...

run a quadrature plate off the servo, divide the plate with 2 wiping contacts - void in the middle. Setup a 'hunting' relay set and these then can drive an inline directional control valve. simple!! if purchased wisely could be done for under $300.

ahhh mechatronics. i love it!

Hey there, not sure excatly what your plan is with this, but just incase check out what ian1974 has done with his power box to run a ram, seen this done b4 as its an old trick, hey maybe you already know! maybe it might help.

p.s sorry haven't worked out to link to it yet.

1MadEngineer wrote:

Simonc3 wrote:Yep, thats about what I want.

No servo made comes close to having enough torque for what I want to do, these torque amplifiers look like what I'm after, but if I can mod a PS box for cheaper, I'm all for it! It needs to be very easy to turn (from the input end) for the normal servos to control.
Also the torque amplifier or PS box only need two main parts whereas the hydraulic sering units require three main parts.

Cheers fellas

easy and cheap to do! just not the way you are thinking...

run a quadrature plate off the servo, divide the plate with 2 wiping contacts - void in the middle. Setup a 'hunting' relay set and these then can drive an inline directional control valve. simple!! if purchased wisely could be done for under $300.

ahhh mechatronics. i love it!

With that setup, would the steering return to center when the servo goes to its home position?

BEEPJEEP wrote:Hey there, not sure excatly what your plan is with this, but just incase check out what ian1974 has done with his power box to run a ram, seen this done b4 as its an old trick, hey maybe you already know! maybe it might help.

p.s sorry haven't worked out to link to it yet

Sound good, I'll check it out