Differential steering

[bigdeano]

Old WWII military equipment with an expected lifetime of hours ? Modern Military equipment?
Even bulldozers steer by disengaging the desired track's clutch pack for a majority of turns without getting into brake activation.. Self Propelled swathers are usually considered the best turning machine around and usually with the capability of full power to both drive wheels.
The Argo's of recent years from Ontario Drive and Gear use variable speed drive for most turns. Differential braking is for only the sharpest of turns.
Keep checking the classified ads. Sooner or later you can purchase a running 8WD Argo for less than the cost of a home built contraption,
ARGO 8-wheeled Amphibious All Terrain Vehicle | 700 HD UTV

The M1 tank uses differential steering. The M60 tank used it 45 years ago. Caterpillar is using differential steering on a lot of their crawlers. I'm not talking about differential braking. Steering clutches are obsolete . I think the Argo uses variable ratio pulleys. That's not suitable for heavy equipment.

 

[buickanddeere]

The M1 tank uses differential steering. The M60 tank used it 45 years ago. Caterpillar is using differential steering on a lot of their crawlers. I'm not talking about differential braking. Steering clutches are obsolete . I think the Argo uses variable ratio pulleys. That's not suitable for heavy equipment.

The M1 series was supposed to get an update on the transmission and the fuel hog gas turbine. Same budget cuts that prevented the B52 being re-fitted with more efficient high bypass turbines . The money wasted on the F35 should have went to those projects. I was under the impression that most modern tracked vehicles first disconnected a drive clutch to the desired track. If a tighter was desired then that track's brake was applied.
If all electric drives are implemented . Clutches and brakes will be a mute point.

 

[bcp]

Free ideas here:

Notes on Tracked Vehilcle Steering

Buy an idea here:

A Low Cost Tracked Vehicle Steering System Design Providing Pivot Turning and Infinitely Variable Turning Radius

Bruce

 

[bigdeano]

You just need two differentials with the wheel flanges hooked together with a chain drive on one side and a gear drive on the other side. The wheel flanges on the second differential turn in opposite directions while the ones on the first turn in the same direction. If the pinion on the second differential is held stationary, the wheel flanges on the first differential are forced to turn the same speed in the same direction. If you have tracks driven by the first differential you will go straight.

If you turn the pinion of the second differential, say with a hydraulic motor, the tracks will turn at different speeds while still both receiving power. It's infinitely variable steering with small losses. The steering motor only handles a fraction of the power of the main drive.

 

[CNC Dan]

bigdeano has it right. I saw this setup in a Popular Mechanics magazine a long time ago.

The spider gears will be turning a lot in the stering axle, but for tracked vehicles the speed wouldn't be that high. Chose an axle with an easily replaceable third member and switch to full synthetic gear oil and you should be ok.

 

[FarmWrench]

Oliver OC-3 was true differential steering. One diff with breaks to turn. Very smooth for cultivating.

I didn't read the other replies but I wouldn't doubt someone has mentioned that if you replace the breaks on your "outside differentials" and connect them with roller chain and a hydraulic motor, you could achieve counter rotation. Cat D6 style.

 

[Fallon]

Free ideas here:

Notes on Tracked Vehilcle Steering

Buy an idea here:

A Low Cost Tracked Vehicle Steering System Design Providing Pivot Turning and Infinitely Variable Turning Radius

Bruce

Cool links. Never thought about track steering theory. One if these days I will get or make a crawler of some sort just because they are cool.

 

[VroomVroom]

If I was to slap a drive train and regular truck rear end with brake steering, my only problem now would be methods to have the brake drum or disks mounted so that a sprocket can be mounted and tire guides won't hook thr drum. Any methods or ideas ? I can't contact many who've built something on YouTube. I was thinking a c channel frame with two sprockets driving the tracks. And simple bogie system Flat deck to carry a little. Used just to retrieve moose off trail. Until I can replace a j5 or two. I can't open the above link or it seems you have to pay

 

[bcp]

This appears to be a source. Maybe they will do an interlibrary loan.

A low cost tracked vehicle steering system design providing pivot turning and infinitely variable turning radius (Book, 1992) [WorldCat.org]

Bruce

 

[Renze]

The M1 series was supposed to get an update on the transmission and the fuel hog gas turbine. Same budget cuts that prevented the B52 being re-fitted with more efficient high bypass turbines . The money wasted on the F35 should have went to those projects.

Here in Holland the same thing. The government kisses Lockheed Martins asses hoping to get a slice of the pie for our aviation components industry, but we're all being screwed by the consortium that builds the F35. Its development is funded by the US government and therefor there is no desire to get the thing actually operational, because revenue comes in whether its operational or not. Meanwhile the price tag for a single unit is exceeded more than double than when the contracts were signed with individual counties that wanted these.

Europe has some great fighter jets, the Swedish Saab Gripen and the French Dassault Rafale (Dassault is also the company behind SolidWorks by the way) but somehow the policy makers want to ride with the US because it would be easier to work in NATO joint missions... Well the way the US is ran economically these days, and how Putin rolls in the Crimea and Syria, soon we better buy a Russian MiG if we'd want to have the same thing as the worlds superpower....

America?s new trillion-dollar fighter jet under fire again - Fortune
COOLER M1 ABRAMS TANK ENGINES