Help !! Planetary Hub reduction truck rear axles

Hi and a merry Christmas to you all.

I have seen quite a few trucks about that have planetary gear reduction hubs on their rear axles. Does anyone out there know what the ratios of the diff and the hubs would be, and are there any pics about of how they work and transmit the drive from the prop shaft to the wheels.

It was a Leyland trademark ,the hub reduction axle.The halfshaft has a gear built into it's outer end. A planetary gearset transmits the motion to the fully floating hub. A good Idea because the differential could be smaller (lighter, more ground clearance.) . The halfshaft could be lighter because the torque multiplication is lower at that point. The only drawback is that hub seals have to be good.

It was a Leyland trademark ,the hub reduction axle.The halfshaft has a gear built into it's outer end. A planetary gearset transmits the motion to the fully floating hub. A good Idea because the differential could be smaller (lighter, more ground clearance.) . The halfshaft could be lighter because the torque multiplication is lower at that point. The only drawback is that hub seals have to be good.

And Foden, and Magirus Deutz and Scammell lots of others

A good one to look at today are Mercedes tipper trucks , they have a really slim diff , not sure what ratio difference there might be ,, ,, Also loading shovels and JCB's + dumpers .

normally have a cog on the end of the half shaft then three planetary gears , then the outer hub is an inverted cog , so the half shaft often turns in opposite direction to wheel travel ,,,,,,,,, the diff is going to be high ratio to compensate for the finale reduction ,, A lot of auto transmissions use banks of planetary gears ,,

I always relate these hubs to the old chain drive bogies. I'm sure the Pacific M26 Dragon had reduction hubs on the front and chain drives on the back, which sort of makes sense if you think about it as it is pretty much the same layout but with gear faces instead of sprocket faces and chain. Wonder if anyone knows if the reduction ratio on a Pacific front axle is the same as the sprocket ratio on the back? - anyone?

Mack NO series front axles, Volkswagen camper vans, Kubel rear ends, loads of these things about.

, Volkswagen camper vans, Kubel rear ends, loads of these things about.

these only have a reduction box as a means to raise the vehicle height and also lower the gear ratio ,, a cog on the end of the half shaft and one on output wheel shaft ,, ( like a unimog portal axle )

The hub reduction in the Foden heavy haulage vehicles of the 50's and later was selectable. With a tomy bar you slid a gear either to mesh with the epicyclic planet gears or the other way the sliding element locked into the hub itself giving direct drive.

Usually slid one way running empty, or lightly laden in fairly flat country, or the other way (into epicyclic) for heavvy loads in hilly terrain.

Best of both worlds!

Best of both worlds!

As long as you remembered to do all 4:cool2:

Hi and a merry Christmas to you all.

 

I have seen quite a few trucks about that have planetary gear reduction hubs on their rear axles. Does anyone out there know what the ratios of the diff and the hubs would be, and are there any pics about of how they work and transmit the drive from the prop shaft to the wheels.

On the SOMA axles used on the S26, the crownwheel/pinion gear sets can be between 35x7 and 27x20. The hubs are about 4:1 while the overall axle ratio would be about 7:1 for medium duty work up to about 100 tons. I can scan a good picture from the manual when I get home.

On the SOMA axles used on the S26, the crownwheel/pinion gear sets can be between 35x7 and 27x20. The hubs are about 4:1 while the overall axle ratio would be about 7:1 for medium duty work up to about 100 tons. I can scan a good picture from the manual when I get home.

Mmmm yes please would be very interesting.

Not all hub reductions are laid out the same, take for instance, the Ferret Mk and 2. The shaft from the bevel box has the sun gear on the end, driving planet gears which are held in a carrier fixed to axle end, and driving the hub by the annulus or ring gear.

Now look at a Ferret Mk4 and a CVR(W) Fox, driveshaft from bevel box again has sun gear attached, but here things change and the planet carrier is fixed to the hub, the annulus is the fixed point this time locked to the axle end.

Wasn't the AEC R6T hub rdeduction?

Right, so as I thought about the layout but would like some pics or tech pic and if possible some general specs of diff ratios and hub ratios.

Mmmm yes please would be very interesting.

Here you go, typical Albion layout.

Halfshaft 12 drives the sun gear 10.

The annulus wheel 21 is held stationary on the axle case by anchor gear 35

The driving flange 13 and planet carrier 20 are driven by 4 planet gears 18 which are located by pins 15 fixed to the planet carrier 20

The gear ratio is the ratio of teeth on the sun gear to the teeth on the annulus wheel, the planet gears are purely idlers.

My dad's the one to ask about this, he had a transport company with all sorts of hgv's.

Thanks for the post of the exploded view just right but how about diff ratios and some pics of them and the half shafts please.

but how about diff ratios and some pics of them and the half shafts please.

Diff ratios and planetary gear ratios would vary depending on the particular vehicle, wheel size, intended road speed, gross weight and other factors. A bit like how long is a piece of string. What type of vehicle are you particularly interested in?

Thanks for the post of the exploded view just right but how about diff ratios and some pics of them and the half shafts please.

From my previous post:

>On the SOMA axles used on the S26, the crownwheel/pinion gear sets can be between 35x7 and 27x20. The hubs are about 4:1 while the overall axle ratio would be about 7:1 for medium duty work up to about 100 tons.<

The half shaft is clearly shown in post 14, item 12, and is splined to accept the sun gear rather than having a drive flange.

The crown wheel, pinion and half shaft are similar to a conventional axle but lighter duty as the torque is produced at the hubs. The highest overall reduction would use the 35/7 cw/p to give a 5:1 which multiplied by the 4:1 hubs gives 20:1. This would be used on something like a site dumper or yard crane operating at low speeds while at the other end of the scale the 27/20 cw/p gives an overall ratio of about 4.8:1 suitable for 70mph.

Diff ratios and planetary gear ratios would vary depending on the particular vehicle, wheel size, intended road speed, gross weight and other factors. A bit like how long is a piece of string. What type of vehicle are you particularly interested in?

No particular vehicle in mind, just a rough guide, with reference to the difference between the diff ratio and hub ratio and what they would be, for say a modern road going 8 wheel tipper , only an example.

Also what would the rough weight of one of these types of axle be ?

http://www.meritorhvs.com/Product_CVS.aspx?product_id=9&top_nav_str=hvs##SP16

http://www.sisuaxles.com/technical%20library/pdf/Hub%20Reduction%20BTE.pdf

http://www.man-engines.com/datapool/mediapool/600/D11368e_rear_axles_planetary-hub.PDF

http://www.dana.com/offhighway_systems/axles.shtm

http://www.axletech.com/product_info/pdf/standard/axlecarrierratios.pdf

http://www.arvinmeritor.com/media_room/BirminghamCVShow2007/overviews/AxleProducts07_UK.pdf

or if non of these are helpful why not google "Planetry hub reduction" or similar and read through the hundreds of pages that magically appear!