hair-brain half-baked idea coming right up

[F4Phantom]

Please dont flame me too much for this idea BUT... why would this not work

machine a box 300mm long 200mm wide and 150mm thick (I mean properly machined not hammered and welded and hacksawed in the backyard) with two shafts in bearings about 150mm apart with a triplex chain. The box is bolted to the axle stubb and the alxe fit to the top shaft so the drive is offset 150mm down to where you attach the wheel. You now have a portal axle for a reasonable cost even when including proper machining.

I can see fitting the disks a problem but obviously not to many others or I would not be entertaining the idea.

anyone care to comment?

[rangieman]

Please dont flame me too much for this idea BUT... why would this not work

machine a box 300mm long 200mm wide and 150mm thick (I mean properly machined not hammered and welded and hacksawed in the backyard) with two shafts in bearings about 150mm apart with a triplex chain. The box is bolted to the axle stubb and the alxe fit to the top shaft so the drive is offset 150mm down to where you attach the wheel. You now have a portal axle for a reasonable cost even when including proper machining.

I can see fitting the disks a problem but obviously not to many others or I would not be entertaining the idea.

anyone care to comment?
Yep you have a serious fetish there:wasntme:

[roverrescue]

Chain driven portal... I guess it would be a trade off between lash and chain wear?

Got a mate who has 6x6ed an old rangie and has used chain drive from 2nd to 3rd diff?

Anythings possible - but surely the hassle of machining for good chain tolerances could be spent making a gear housing and gear set a la "normal" portals?

S

[stirlsilver]

Yeah, I think the same, there chain as it wears could become a problem... But then again the rover transmissions have that much play in them already that it probably won't make it much worse.

If you were considring doing this with bearings and what not, you might as well use 3 spur gears or helical gears to make it more durable (I was a little bored):

https://www.aulro.com/afvb/images/imported/2008/09/946.jpg

[Blknight.aus]

why bother with that...

take a planetry gear set retain the anulus and planetry carrier.

put the wheel on the anulus and then drive the anulus from one planetry gear as opposed from the carrier. Instant portal with substantial reduction and less moving parts allowing you to fit those extra huge "why does that unimog I parked next to have licorice strip tyres?" rubbers you never knew you always wanted without reducing your diffs innards to swarf of increasing the parts count of your halfshaft.

[JDNSW]

I think I would be looking at the maximum allowable torque loads for chains before getting two far with the design. I suspect you would be looking at at least a four row chain, and possibly wider, which is likely to find your tyre centreline moving well out from the swivel. Also, you need to have some means of tensioning the chain, suggesting an idler. Whole thing is beginning to get complicated - I think I prefer Dave's plan. But still be a lot of work.

And at the risk of again usurping Ron's job, that is hare-brained, not hair-brain. The term comes from the erratic behaviour of the animal, nothing to do with the stuff on your head.

John

[Bigbjorn]

In the fifties and sixties there was a tandem drive conversion for single axle drive trucks using v-belts from the driven axle to the rear additional axle. Had some limited popularity with tipper operators. Most likely on the basis of price, being a cheaper way of increasing carrying capacity of an existing lighter duty truck than buying a tandem drive truck.
Chain drives were common in veteran, cars and on trucks right through the thirties.

[mcrover]

I have had similar setups on machines such as coring machine and scarifier.

They are light weight and slow moving and they still wear out tripple chains and sprockets regularly.

I dont think it would take any amount of Hp with any real success.

The tripple gears would work well and wouldnt be that expensive, I just had 3 gears and a carrier made up for a planetary set in a bobcat trencher which cost $320, but I did have the original bits of the old ones for him to copy.

[F4Phantom]

I did think of helical gears at first but figured having 3 in a row with reasonable teeth and outer diameter the size would be to big, but I now think it would be ok given that a chain is not strong enough. I even thought a wide timing belt would be ok. I have not got my head around the "annulus and planetary carrier" idea yet.

The biggest problem would be alignment and vibration. Strength is easy, just use something tougher and harder than mild steel.

I was thinking of attaching a bolt on portal device to my weekend tyres permanently as I got some 35 baja claws.

[Blknight.aus]

when you look at a simple plantery gear your looking at 3 layers of gears with a total of usually 5 gears

1 gear right in the middle thats the sun gear, one that we're not using in this example

3 gears attached to some kind of drive plate or ring these are your planetries and are mounted on the planetry carrier

a final gear with the teeth facing inwards this is the anulus.

we dont need the sun gear in this application as it shares the same center of rotation as all the other gears except the planetry gears it will also when driven in the manner we are looking at provide a reverse drive so lets loose that.

the anulus is the big gear on the outside and it re-attaches to the centerline of the entire unit and since its the driven member thats what we want, as its reduction driven in all circumstnaces that we can come up with in the configuration we're using AND it will rotate in the same direction as the driving gear which means you dont have to worry about extra idler gears.

what we then do is drive a single planetry gear and put it up at the top most position of the setup which provides us with the lift over the centerline of the anulus gear .

if your still having trouble with the idea draw a big circle then draw a line vertically acorss the diameter of the circle. now on that line pick a point somewhere more than halfway out along the radius of the diameter heading towards 12 oclock and then use that as the center point for another circle that contacts the circumferance of the first circle at 12 oclock.

the outside circle is the anulus and the smaller the planetry.

by my rough guesstomathics I reckon i can draw you a setup that should provice about a 3:1 reduction at the axle and give you about 4 inches of lift but it wont run a standard rover rim youd have to look at something like a 20 inch rim to make it fit but it woud be a direct bolt on item that would replace the stub axle and drive flange but would retain your standard half shaft.

[Rangier Rover]

The chain would work. We made a reduction off set drive her for a Mamoth Mixer on same idea. But only Runs at 540 RPM. Chains lasted 1200 hrs and Cogs 2000 hrs:eek:
I've thought about making portals out of VW early combie reduction gear sets. They are straight cut gears. Just use 1 primary and 2 secondary gears. I think it would be strong enough. Making the houseing will be the worst part.
Years ago I joined two Kombi Reduction hubs togeather and put under a VW beatle with 33" tractor tyres. I still have the hubs here now.
It had so much torque it sheared the trailing arms off:eek:. I'll dig them out tomorrow and take pics if you want them.
Tony.

[stirlsilver]

I like Dave's idea of using the Annulus and planetary gears... I drew them up using CAD again and i realised one flaw, the casing will stick out a long way down as it is the output of the annulus that hooks up to the diff and not the planetary gear. So while it would be more mechanically efficient, you will have problems with it being hit and getting hung up. Well.. unless you hook it up to salibury, in which case if you are going to get hung up on this casing you would definitely get hung up on the diff anyway!

This is what a 3:1 reduction setup would look like. The outside diameter of the annulus is 150mm and the input and output shafts are 25mm. I chucked in some needle bearings this time :cool:

https://www.aulro.com/afvb/images/imported/2008/09/899.jpg

https://www.aulro.com/afvb/images/imported/2008/09/900.jpg

[F4Phantom]

Nice drawings Sterling however I think Dave was suggesting not to use the outer gear centre where the sun gear would be as the output shaft as you need a big box and dont use all the potential lift. If you add another planet gear at the bottom being rotated by the annulus you get the same direction output and the same speed with more offset. Also for strength I am not sure how good it would be with the shafts not going all the way through the block with a bearing at each end. There is a lot of weight.

And rangier rover, I was under the impression a chain would do the job as well, but some people had evidence to say it does not. A powerful road bike chain certainly takes a lot of power (100hp+) which is a lot more than a 3.5L v8 rover after transmission and divided by 4 (excepting low first which probably equates to approx 2 - 350nm per wheel). Some harleys use belts for transmission.

[Slunnie]

I'd buy Unimog portal boxs and mount them onto the ends of the Rover axle and flip the diff centre and just enjoy it. It'll also be a lot easier to gain engineering approval and you will have brakes and a setup that is proven. It also removes the complexities of designing and building steering.

Actually... if you hunt around, Volvo's would be even easier.

[Blknight.aus]

thats so close to what I was thinking its outright scarry and the basic idea is perfect But instead of a square casing I was going to utilise a rounded one, my plan for the system included about a 20 inch diameter rim and then internally about a 16 inch diameter anulus gear with a 5 inch planetry. with the outside diameter being some 18 inches giving about 2 inches of clearance to the rim.

I had planned for the singe planatery gear to be supported by a bearing on both sides on a shaft similar to how drive is currently transmitted to the hub va a flange but instead of bolts to mount the drive flange to the planetry they would be a dog pin interface setup. in theory this means that your hub centerline only increases in width by a couple of inches and that could be easily pulled back by use of a suitabley profiled wheel rim.

brakes would be proviced by a wet band brake that was actuated by your normal hydraulic system that applied the band onto the circumference of the annulus.

[F4Phantom]

how about you hollow out the annulus and put jockey wheels in each corner to support it, then you can put straight through axles on planetary gears to support the cars weight better. All the gears could be helical I think as spur gears would sound like your driving in reverse all the time and wear faster.

also you could make the input and output planet gears any size you like to make a reduction.

[stirlsilver]

I'm an idiot.

I just realised that we are talking about these thing being fitted on either end of the axle... Input from the halfshafts and output to the wheels.

I was initially thinking that this was taking the input of the drive shaft and output to the diff.... not that it changes much.

[Swampy]

I found this link here under the articulation pix's.

It's not machined it's fabricated.

Bill's LRs - LR4x4 - The Land Rover Forum (http://forums.lr4x4.com/index.php'showtopic=6428)


Cheers Mick

[F4Phantom]

I'm an idiot.

I just realised that we are talking about these thing being fitted on either end of the axle... Input from the halfshafts and output to the wheels.

I was initially thinking that this was taking the input of the drive shaft and output to the diff.... not that it changes much.

well that explains why I was confused at your 'getting hung up' points.

[mcrover]

I found this link here under the articulation pix's.

It's not machined it's fabricated.

Bill's LRs - LR4x4 - The Land Rover Forum (http://forums.lr4x4.com/index.php'showtopic=6428)


Cheers Mick

They are excellent Swampy, I'd love to see inside 1 :p

[defmec]

get the design of mal story ,go to china get a heap made .mals original design was a very simple and strong design having 4 straight cut gears

[stirlsilver]

Well... It certainly gets complicated going this way. And much wider than using 3 (or 4) gears in line.

https://www.aulro.com/afvb/images/imported/2008/09/871.jpg

https://www.aulro.com/afvb/images/imported/2008/09/872.jpg

https://www.aulro.com/afvb/images/imported/2008/09/873.jpg

The outside diameter of the annulus is 210mm with 90 teeth, the planetarys have 20 teeth.

[F4Phantom]

A very similar discussion happened on another LR forum. Worth a read, many of the same ideas plus a few more good ones. It seems some people have been successful in making bolt on portals at home.

bespoke portal drop boxes/axles - LR4x4 - The Land Rover Forum (http://forums.lr4x4.com/index.php'showtopic=23081)

[mcrover]

I just rememberd that F100, F250 and F350 transfer cases (I dont know what make probably Borg Warner being ford) ran chain drive.

So in that case if you could get that style of chain and having 1 on each corner then it should work and be quite reliable.

I have managed to break some links in one of those transfer cases with my old F350 but I had 5 tonnes of goose neck trailer on the back and skipping it into position in 4wd low and it didnt take it all that well.

But it did last a fair while before it crapped itself.

Im going to have a bit more of a look into it and see if I can chase up some pics of the inside of one of these cases and to see if it would be feasable.

[JDNSW]

I just rememberd that F100, F250 and F350 transfer cases (I dont know what make probably Borg Warner being ford) ran chain drive.

So in that case if you could get that style of chain and having 1 on each corner then it should work and be quite reliable.

I have managed to break some links in one of those transfer cases with my old F350 but I had 5 tonnes of goose neck trailer on the back and skipping it into position in 4wd low and it didnt take it all that well.

But it did last a fair while before it crapped itself.

Im going to have a bit more of a look into it and see if I can chase up some pics of the inside of one of these cases and to see if it would be feasable.

To compare with portal boxes you would have to multiply the torque by the diff ratio and divide by the number of wheels (provided there are no diff locks!), which would come out about the same, but if there are diff locks all round the (maximum) torque would be the torque at the transfer case multiplied by whatever the diff ratio is. So on the face of it, it should work.

But can you use sprockets as large as those in the transfer case? The load on the chin is inversely proportional to the sprocket diameter.

John

[F4Phantom]

my money so far is on this, its simple, strong and compact.

https://www.aulro.com/afvb/images/imported/2008/09/726.jpg

[ashtrans]

get the design of mal story ,go to china get a heap made .mals original design was a very simple and strong design having 4 straight cut gears


the design was good but the CV let them down, it used the early RR 606660? one, we have used one of our HD CV's, cut the stub off and spark eroded the 10 spline in the bell to make a HD version of this for a few customers,

Dave

[p38arover]

I found this link here under the articulation pix's.

It's not machined it's fabricated.

Bill's LRs - LR4x4 - The Land Rover Forum (http://forums.lr4x4.com/index.php'showtopic=6428)


Cheers Mick


Did you notice that Bill lives in Melbourne?