How does a differential work?
 

http://www.youtube.com/watch?v=K4JhruinbWc

Before I watched this video, I knew what a differential did but didn't really understand how it did it. Now I know.

Nice, now I know.

that model/mockup of a cars rear end (tires, shafts, basic bearings and tinker-toy 'differential' is awesome.

Too bad that the simply mechanical elegance is being replaced by viscous couplings (that have many more failure points)

-John

That is the best visual explaination for how a differential works that I've ever seen. I like the trick riding in the begining, though I have no idea what that has to do with differentials.

That was brilliant. Thanks for posting it!

simple breakdown of how FWD works along with differentials http://www.youtube.com/watch?v=TlQ6KRqUepg

That is good. I first saw the principle of planetary gears in action with my old Saab 96. They had a weak clutch/tranny setup and I had the engine/transaxle out about 9 times over 6 years IIRC. A smarter man probably would have gotten rid of it.

I forget how exactly but when the tranny was opened up you could see the FWD differential. Cute as could be, all those well machined gears working so smoothly. A little bit of playing around with it and I could see how it worked and why vehicles w/o posi-traction or LSD can get stuck in the mud with the wheel with the least traction spinning.

I think with rear wheel drive cars, there's less opportunity to see the inner workings of the differential as it is rarely taken apart and repaired by the average guy.

When I played with Lego Technic models, that taught me how differentials worked (model 8880 was a Supercar that had 3 differentials, 4WD, 4-speed manual transmission and 4-wheel steering. That was a fun car to build.

Outstanding. The use of a rod to push both sides at the same time leads directly to the understanding of more spokes, and finally, gears doing the job.

Thanks for posting that!

Its no wonder kids were smarter/more science oriented back then, the emphasis on learning stuff like that was much higher.

Parents and educators thought less of the poor little dears' self image, and more one "hard" science, and truth. Truths like--the race goes to the swift. Not everyone wins; not everyone excels.

I think it has less to do with time and place and more to do with a sharp person who understood differntials and knew how to communicate that knowledge effectively in a very simple manner. I think that a pretty high percentage of people who knew exactly how and why differentials worked couldn't have come up with that simple model to explain it to the ignorant.
I've looked at a number of differentials in my day, saw what was happening but didn't understand it.

Now they just need to make one of those for an inline injection pump.

Differentials have been in use since the earliest days of the automobile, so I am guessing that the operation was pretty obvious to those pioneers.

The genius is the guy who first thought of the idea. I wonder what was the original problem that was the impetus for someone to create this solution. I bet it predates the need to have one wheel of a driven axle go faster than the other on a curve.

Another favorite canard of the right.

. . . thought less of the poor little dears' self image . . .

People can get damaged for life by overbearing, cruel people. Why are some people filled with self-confidence and courage while others are afraid to take risks? A bit of attention to this subject strikes me as a worthy task.