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1937 film explains how a car differential works

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Re: 1937 film explains how a car differential works

#141

Post by leowoo91 »

thomasahle wrote: post #118
nimbius wrote: post #97

I work as a diesel engine technician for a small midwestern chain and I whip this video out in the breakroom whenever the apprentice gets an idler/pitman or diff rebuild on a large truck. So many of the guys i work with know about LSD (Limited Slip Differentials) and locking differentials/hubs, but dont entirely understand why they are needed or how they work once the wheels are back on the ground. if you really want…

I watched those two other videos, the second one twice, but I still don't really understand them. The 1937 video clicked perfectly on the first viewing.

I've tried thinking hard on the second video. I guess most confusion comes from as it doesn't explain why traction situation (where wheel speeds up relatively) is different than the actual turn (where wheel slows down relatively). Here, as speeding up wheel gear can not spin the worm gear, power is captured "back" to the other wheel through the outer locking cage. However, first comment at youtube and an another article (https://www.kmpdrivetrain.com/differentials/torsen-vs-plated...) states that it wouldn't work with 0 traction and can get only the amount of slipping traction torque to the other wheel.

Re: 1937 film explains how a car differential works

#142

Post by giansegato »

ardy42 wrote: post #140
tqi wrote: post #89

The lack of background music and pace is really interesting to me. Compared to a typical "how it's made" video [1] (which I feel has a similar level of detail), this video feels significantly more digestible. Those moments of silence feel totally alien and out of place in today's style, but I think contributes positively to my ability to understand and process the information. [1] https://youtu.be/8gno0_emzo8

> The lack of background music and pace is really interesting to me. Compared to a typical "how it's made" video [1] (which I feel has a similar level of detail), this video feels significantly more digestible. Those moments of silence feel totally alien and out of place in today's style, but I think contributes positively to my ability to understand and process the information. I think that's because the older movie…

Agree. I got quite interested in the topic in the past [1] — it ultimately boils down to optimizing for attention (modern YouTube) vs optimizing for data retention (traditional education).

[1] https://giansegato.com/essays/edutainment-is-not-learning/

Re: 1937 film explains how a car differential works

#143

Post by globular-toast »

tzs wrote: post #68

A good thing about that film is that after seeing it if I can't remember how a differential works I usually can remember the steps they took to get to how a differential works and then figure it out myself from there. That suggests that it didn't just tell me how a differential works. It taught me how someone who needs to invent a differential should think about the problem.

This is my favourite way of learning (and teaching) most things. I hate when I'm just told "this is the way it is". I want to know why, what problems does it solve and how was this developed.

Re: 1937 film explains how a car differential works

#144

Post by souprock »

Animats wrote: post #110
zackmorris wrote: post #94

Stumbled onto this explanation of how a Torsen differential works. I'm still trying to wrap my head around it, but it basically uses the one-way nature oh how a worm gear can turn a regular gear but not the other way around (due to the high gear ratio involved). So in this differential, the housing can turn both wheels simultaneously, but if one wheel slips and becomes free, it can't direct the torque to the free whe…

Oh, that's a clever design. The explanation, even with all those graphics, is poor. The idea is that one wheel can go slower than the speed it would go if the axle was rigid, but it can't go faster . With that design (which seems to be a Torsen Type A), the faster wheel does all the work of propelling the vehicle on turns, but the wheels lock together if one starts to slip. So it's for off-road vehicles, like the mil…

There was a Torsen Type A in the B5 platform revision of the Volkswagen Passat 4motion. It was in the center. Front and rear were plain differentials, with the brakes used for left-right issues.

It worked very nicely on highways.

Re: 1937 film explains how a car differential works

#145

Post by technothrasher »

GekkePrutser wrote: post #133
mattmaroon wrote: post #127

Earlier quoted context omitted.

The first video explains differential locks. Basically with an open differential all power would be routed to a wheel that’s getting no traction (for instance if it’s on ice). A differential lock closes it, so it’s as if there were no differential, so both wheels on the axle will turn at the same speed. This is bad if you’re on a normal road (obviously, since that’s why differential were invented) but great in low tr…

Yeah I believe this is how modern cars with traction control work, they brake the slioping wheel so the one with contact can get the traction. At least this is how it was explained to me by my mechanic friend

Applying the brake on the slipping wheel is one half of traction control. Reducing the power going to the wheel is the other half. I accidentally demonstrated this to myself many years ago when my car suddenly was almost completely ignoring my throttle input for a reason I couldn't explain. It turned out I still had the parking brake on and when I went over a patch of ice and the car lost traction, adding more brake wouldn't do much, so it simply ignored my throttle. Because I wasn't moving more than about 5 miles per hour to begin with, it felt like the car just refused to move, like a stubborn mule.

Re: 1937 film explains how a car differential works

#146

Post by gumby »

thomasahle wrote: post #118
nimbius wrote: post #97

I work as a diesel engine technician for a small midwestern chain and I whip this video out in the breakroom whenever the apprentice gets an idler/pitman or diff rebuild on a large truck. So many of the guys i work with know about LSD (Limited Slip Differentials) and locking differentials/hubs, but dont entirely understand why they are needed or how they work once the wheels are back on the ground. if you really want…

I watched those two other videos, the second one twice, but I still don't really understand them. The 1937 video clicked perfectly on the first viewing.

A simple way to think of it is that “locking the differential” could be thought of as disabling it, turning it back into a conventional axle.

So this is useful when you’d prefer a conventional axle: when one one side has a grip and the other side none.

Re: 1937 film explains how a car differential works

#147

Post by GekkePrutser »

technothrasher wrote: post #145
GekkePrutser wrote: post #133

Earlier quoted context omitted.

Yeah I believe this is how modern cars with traction control work, they brake the slioping wheel so the one with contact can get the traction. At least this is how it was explained to me by my mechanic friend

Applying the brake on the slipping wheel is one half of traction control. Reducing the power going to the wheel is the other half. I accidentally demonstrated this to myself many years ago when my car suddenly was almost completely ignoring my throttle input for a reason I couldn't explain. It turned out I still had the parking brake on and when I went over a patch of ice and the car lost traction, adding more brake…

Thanks for the explanation, I didn't know that!

It is amazingly effective indeed. One time I was driving through ice and snow, and at the traffic light I turned of the ESP by mistake (was trying to plug in my phone charger in the lighter socket beside the button). When I took off I nearly crashed myself off the road, I never realised how slippery it was, and how much the car was covering for my ignorance.

Re: 1937 film explains how a car differential works

#148

Post by ehnto »

kenjackson wrote: post #86
ehnto wrote: post #46

Earlier quoted context omitted.

I get so tired out by the constant filler in written and video articles of education. At the same time, the internet is becoming harder and harder to search for specific bits of information in lists, encyclopedias or other easily referenced and digestible formats. Earlier today I was trying to find a list of all Alfa Romeo models to identify a car, and all the top results were ten paragraphs of SEO infused filler bul…

I searched for Alfa Romeo models and my top hit was Wikipedia that listed all the models (I think).

Which is what I ended up using then googling each model to find images. Years ago I would expect Google to find a great array of enthusiast blogs that might have them properly catalogued, but nowadays it's mostly content marketing articles. Stuff like this: https://www.motortrend.com/features-collections/most-beautif...

It's an op-ed designed to get clicks and turn ad dollars, in a format that extracts even more clicks once you arrive. That's what's frustrating, all the genuine information is being replaced with content marketing apparatuses. That's not really Google's fault intentionally, it's just how the ecosystem has evolved.

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