Off topic, but what are the advantages of this track setup?

[MarkW]

My son asked me why the sprockets were set up this way on a dozer that was doing some work next to the highway, and I said I'd find out as I don't know:


I suspect it is to keep the engine/trans/whatever else linkage as short as possible and possibly save a bit of weight, but then it would seem to me there is a bit of power loss if the back sprocket becomes a large idler instead of a driver, but I would like to hear from someone who actually knows about it rather than me just guessing!

Thanks all!



Mark

[digitup2]

Well the elevated sprockets were intended to take the sprocket out of the dirt I have an older D4H and a D6M they are both elevated but the wear rate was 20% more than conventional drive system .They are nice to operate as the elevated drive is a bit smoother in hard going with no chuck and bounce from the drive sprockets like conventional .Cat has went back to the old drive system to be competitive with the new D7E that is electric motive driven as well like a train engine .That machine is made in China and they have no panted infringement worry's in that country I figure it was a passing fad.Digitup.

[Lavoy]

A friend who is an engineer at Cat said that one of the reasons was to get the final drive up out of the dirt for seal longevity. Another I think was shock load to axle shaft like would occur on standard drive type.
Lavoy

[440 iron popper]

The final drives, the steering clutch and brake, and the bevel gear are located on a common center line. The removal and installation of the power train components is much easier than earlier track-type tractors. Also, the final drives are positioned above most of the abrasive material and the packing conditions that occur during operation. Also, there is a reduction of shock loads through many of the power train components. (Shock loads are either forces that are caused by impact with the ground during operation, or forces that are caused when the implements are suddenly engaged.) In this elevated location, the final drives do not support any of the weight of the machine. This permits the undercarriage and suspension to be made resilient.

I copied/paste the few lines that talk about it in the undercarriage system operation of a D10R dozer.

[MarkW]

Thanks for the information guys!

You learn something new every day.


Mark

[vestor_guy]

" the wear rate was 20% more than conventional drive system "

It looks like the engineers didn't have that idea right. When you look at it, it should be obvious that with fewer sproket teeth engaged with the track at any time, the pressure on the pins and sproket teeth would probably be significantly higher and also track tension might be more critical.

[Tigerhaze]

I thought these were pretty intersting threads on the elevated sprocket vs. standard sprocket models:

http://www.heavyequipmentforums.com/sho ... High+track

http://www.ytmag.com/cgi-bin/viewit.cgi ... s&th=73972

A post in the first thread indicated that Deere published an engineering report on the concept and the reason they passed on it, but I was unable to find it.

This last link (bottom half of the page) provides the most convincing reason for the elevated sprocket models; they state it was a way to make use of stronger planetary finals instead of the standard finals and it takes the weight of the machine off of the sprocket/finals.

http://www.vannattabros.com/iron19.html

[digitup2]

Well owning two of the dam things I look at it like this #1If they could build the finals bigger then just when will they start building finals bigger and stronger? #2 if the rear ends and trany is placed better for service a 850J Deere is quicker and cheaper to work on than a D6M any day .#3 I own both and the Deere is a more maneuverable and a harder pusher any day any conditions and also #4 the Deere uses 100 bucks less fuel per day to boot.#5 I know that they are close competitors with each other but I got the Cat and the Deere both used and at good deals but you don't want to see the price on the Cat new price compared to the Deere new price either .The Cat dose have better resale value though!!:shock: Digitup