What is better?

[JDdude]

The front axle on the Kubota has a different setup than the Deere 4 wheel drive..JD is like a Auto with the differential in the center and the Kubota has the differental-s at the wheel like some other brands of large tractors..

Which is better and why do they make them different..

I just though this would be a good topic to discuss,real differences in the 2 machines...

Thanks..

 

[texbaylea]

Modern automobiles with the differentials at the center and attached to the frame are built that way to reduce the "unsprung" weight. This improves the ride since more of the automobiles weight is supported by the springs, particularly on rough roads. There are other reasons having to do with overall weight and production aspects. I do not know what the engineering reasons for chosing the different approaches for tractors would be. Possibly has to do with production capabilities.

 

[Woodbeef]

You've lost me on this one. Mfd tractors have center or offset differentials. What is in the hubs is outboard planetary reduction units. On most mfd axles they are in-line with the axles,and have steering knuckles and u-joints to transfer the power straight through. On the Asian tractors and some others like Belarus they feature what is known as bevel drive to the wheels. This allows a higher ground clearance,but the power must drop down to the wheel hubs from the axle.

 

[JDdude]

Ok,where is the diferential on a Kubota front axle? We know where it is on the JD, because it is designed like autos..But the Kubota has no pumpkin as to speak..2 different designes..Totally different..

 

[Henro]

THe front axle on the Kubota is similar to the portal axle on the German Unimog and the axle that is used on the American Hummer.

The advantage is ground clearance. The differential can be higher. As can the shafts that cross from the differential to the wheels, and the axle housing itself.

Another advantage I think is that the torque that is required to be transmitted from the transmission to the front wheels is lessened, because at each wheel there is a small gear driving a larger geat that is somehow connected to the wheel. Mabye someone whol really knows can state something about this aspect of the setup.

THat is about all I know...someone will correct me if I am wrong I am sure... /forums/images/graemlins/smile.gif

 

[RobertN]

On most small Kubota, the diff is in the middle of the axle. It provides primary gear reduction. At the end of the axle, and in the "hub" itself is a second set of gears, providing secondary reduction. Note, this is the same in the rear end too. There is a diff like a car, but there are also secondary reduction.

Double check the Deere; I would bet you a nickle it has secondary reduction too. Maybe, the main front diff is more visible than on other brands...

This kind of setup tends to give some really mean low down crawling overall gearing. In some tractors the secondary gears are offset vertically, to give ground clearance for crop work.

 

[ZJ_HR]

Belarus (newer models) has double U joints too, but final reduction is bull gears, instead of planetary. It just look like Z drive. /forums/images/graemlins/wink.gif
I saw Z drive axle on Kubota M6800, but it looks lighter (more gentle) than on my 45 hp tractor.
IMHO, plantary final reduction is better and more rugged than Z drive for full size tractors, but for CUT-s doesn't matter, as they are machines for non severe tasks.