BOLTR: Sprag Clutch | Engineered Bearings
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- เผยแพร่เมื่อ 26 ม.ค. 2019
- We look inside a one way bearing to see how it works. In this case, it's a sprag clutch type. Thanks for your help making VJOs. I appreciate your help. Early access here / ave
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A simple device that stops you from going the wrong direction. Should be standard on vehicles and dating apps.
and toilet roll holders
Funny you mention vehicles: It's pretty common in an automagic transmission to have a one way clutch (sprags or rollers typically) to allow planetary gear sets and/or clutch packs to keep everything going in the right direction.
Of course, sadly, engineers have yet to figure out a way to have this do anything to take into account the problem between the driver's seat and the steering wheel.
@@astrangeparrot Damn, you beat me to it. Been years since I have had an auto tranny a part.
@@TheLittlered1961 That is why they're call "gearbox" in Urban Dictionary...
Bruh
Wish I had some of those when I was younger. Woulda been fun to replace my buddies' skateboard bearings
Thank you for the idea. I've got skater friends.
Interesting fact; the one-way bearing shown in the picture, can fail to engage the lock, if it spins fast enough in in the unlocked direction, and very suddenly changes direction, then the wedge-balls will ride on an oil film, preventing them from engaging, so it's very important to not rely on these type of bearing for safety..
You see this often on smaller engines using oneway bearings instead of ratchet type pull start systems.
Traxxas nitro cars use one way bearings for starting
@@merlinious01 Exactly! :) but in fact, they are also used in the electric starters for most real cars, in case the pinion fails to disengage from the flywheel/flexplate when starting.
interesting
Thats cool. There's a bicycle hub manufacturer here in the states called Onyx that uses a sprag clutch assembly. Apparently a Duke university study in 2016 determined that the Onyx hub had the lowest rolling resistance in any commercially available bike hub at the time. They're pert spendy though, as one might imagine. Great VJO as always!
I have an Onyx rear hub and I can attest, they are absolutely badass. If you understand how a pawl based hub works, you realize all your pedaling force is transferred through such tiny pawls on such tiny teeth, especially in something like an industry 9 hub. On an Onyx, the whole sprag engages with your pedaling force on the drive shaft (best way I can describe it) so all your force is spread evenly through the hub.
Yes they are spendy, buy onyx hubs are actually game changing. I want them on my road and gravel wheels as well.
I learn more, more quickly from watching your vids like this than I would on a college course.
Love your content, my dude.
A lot of transmissions use sprag bearing especially on 2nd gear drum clutch pack! The keyed inner race gives it away! Great video!
Great breakdown on the Sprag bearing. They are vital in helicopter operations where they are called the Sprag Clutch or Free Wheeling unit/assembly. This is critical to helicopters as they allow the free wheeling of the rotor systems in case of engine failure and allow you to perform a autorotation. It is also used during practice autorotations when the engine is throttled back so that the rotor system disengages with the engine allowing the “free Wheeling’ of the rotors and a controlled (hopefully) decent and landing. Thanks for the video sir.
Every days a school day. I’ve always wondered how they worked but never made the time to learn. Thanks! You’ve educated me.
I’m fairly sure there must be one inside a new Fly Fishing reel as it runs smooth and silent in wind in, but a friction clutch engages in reverse. It’s not the usual ratchet and pawl mechanism. I’ll be thinking of you next I’m winding in a trout. If that’s not the weirdest compliment, I don’t know what is!
We don't need to know what you're thinking about when you're winding your rod... :-P
In all the years you've been entertaining me, I've learnt something I didn't know already. I salute you.
Ave has one of the best informational and educational channels on TH-cam. For anyone who likes to tinker with things and take things apart to see how they work this is the perfect channel to watch.
One of the most interesting trips I did was to SKF. They have this little exhibition in the foyer showing where their bearings are. Any kind of machinery that rotates, anywhere on the planet and off it, probably has an SKF bearing in it. There are a few other big bearing manufacturers too. SKF is a fascinating company.
In all my years I've never seen a bearing like that... Cunningly simple, as most of the best ideas are.
Thanks for sharing.
This is the only channel I've ever even considered becoming a Patron for. Thanks for whatcha do AvE
Yeah i wish i had some extra.
Cheap fucker
Balls and wedgies - it's like being 12 all over again
Funny, I cut one of these in half just an hour ago since I was curious how it works. Simpler than I thought. It was a bike sprocket thing.
“Freehub”
@@cameronrobertson9518 Patreons get early access
*spoiler alert!*
We had a needle roller bearing application at work. A ramp on the bearing cage did the one way binding. Useful feature in a tiny package. Thanks for the video.
Torquflite 727 learned me about sprags, they are pretty groovy things
Love when you share little ingenious things like this. Industrial oddities are so interesting!
Interesting, as always, another clever piece of engineering that is taken for granted. I never realised each time I use my keyless chuck that this is what's inside. Thanks for showing me.
Always wondered how these things worked, but never had the chance to pull one apart myself. This is quite a neat little design.
I dissected one at work on an armor zone tape pull system. It was the ball style. Pretty cool engineering to prevent backlash that would definitely cause tension loss. The machined wedge insert makes for a nice stought bearing that holds up well.
Long-time subscriber and lover of your channel here. Was browsing in a used tool shop this morning and picked-up a NOS formsprag clutch and even more interesting...a formsprag clutch dealer’s sample. A neat little brass version with a plexiglass window showing the inner mechanism. Happy to send it your way if you’d be interested in making new content on this.
I never knew these bearings existed. I learn something new in every one of your videos. Without fail.
Thanks for sharing AvE! Didn't know about this flavor of bearing but now I see them everywhere. Or at least my machinist buddy sees them everywhere and he told me about it when I asked him
My Thesis, Final year project, was a wheelchair design that raised the seat so the occupant can speak to someone on a face to face level or maybe reach into an upper cabinet.
I used a Sprag clutch on both sides of the chair actuators in my design but it was two-way. Only the power shaft (up or down) could drive the final mover.
The clutch was mainly used on escalators. A small one was VERY expensive but needed as a safety device.
I was the Top Dog of the year with that project.
I found out about these for the first time when is was attempting to rebuild a spinning reel. They were basically the lynchpin of the whole setup. 200$ reel fixed by a 3 dollar bearing. Ordered from Canada btw!! Awesome video as always!
Never realized you were such a One Direction fan *giggles*
0:11 "It's Huan Wai." Your Chinesium jokes are getting rather complex.
Almost went right by.....I snagged her though.
I thought it meant juan guey
I love your channel and all your content. I can't tell you how invaluable all your vids have been to me. It had recently occurred to me that I almost never leave a comment. Always a thumbs up though but I plan to be a little more active in the doobly-do. Thanks for everything you do. ✌Keith from Long Island New York !
I never knew there were one way bearings. I learned something new. Thank you for the fun and interesting content. I hope you are feeling ok.
The deadpan delivery of your subtle and slightly inappropriate (perfect) humor is excellent 😁
Love this stuff man. Learned on the fly about these the other day trying to unfix a fancy fishing reel. A little different though. The rolling element was the part that was preloaded and would actually catch on a fixed cam ring that served as the "outer race" and catch the "inner race" stopping the whole rotor.
I didn't know these existed until your video. It's just solved a problem with a worm driven mechanism I'm designing which also needs to freewheel in one direction.
I can't tell you how helpful this was.... This is something I always wish I learned in school!!!
Good description. The part about the drill was very interesting.
The overdrive, on my 64 Volvo P1800, had one. With an electric over hydraulic, planetary gear set too. Cutest little thing ever.
Thanks for the video, I always wondered what it looked like inside because True Precision is a company that makes one of the best hubs for bmx wheels. They use these bearings with a cog attached to it, and it
provides instant engagement and less drag than the common cassette type hub for competition racing.
I worked at a limestone quarry and MSHA came in for a inspection and made us put “Backstop Bearings” on every rock conveyor we had, they were very expensive and a pain in the ass to install too.
Keep up the good work man. Huge fan for real. As a fellow man in the trades (an elecchicken), i truly love the humor, knowledge, and everything in between.
Me, too. I'm a huge fan for fake.
@@johnpossum556 good day my friend. How bout we don't pollute a good man's page with nonsense. Appreciation is appreciation regardless of your opinion, let me word it, or show how i want to, and you do the same. Tomatoes, tomatos.
@@brandonrabe5710 You're so right. We wouldn't want any humor on this channel. If you really were a true fan you'd already know this enough not to try to put me in my place. Later...
Nice video.. the old Arpeco printing presses I work on here in the UK have the sprag bearings , they do fail more often than 'normal' bearings but are still fascinating... I've never had time to take one apart ...so thanks for the video.... The Arpeco's were Canadian machines originally.
I had no clue they made bearings like that till now. Thank you.
Sprag clutches/bearings have been the bane of my existence one was in the starter for my dad's triumph sprint it would always fail when we wanted to ride
Ive seen those when i was a kid. I took the bearing apart to see why it worked in that manner. Very interesting.
As always...thanks for having me in the shop.
I've encountered these in my fly fishing reels. When retrieving the line it spins freely and when pulling more line out (or on some rare occasions when you actually manage to hook a fish) it locks and the spool spins against the disc brake system. Pretty nice compared to some cheap reels where the brake applies to both directions. Also, if you want to switch the reel from right to left hand retrieve, you just flip the bearing. Thanks for showing how they actually work!
Thank you for all the great content uncle AvE!
I learn so much neat stuff from this channel. Its pretty damn great.
The graphic for the explaination of the second type is much appreciated, I wouldn't underwise have gotten it from just the wording because I'm more the visual type.
The oddest place I found a one way bearing was a paper towel dispenser.
hahahaha
I've seen one of these on the ribbon-feed pulley on a dot-matrix printer. The pulley was coupled to the print carriage, which could move in both reverse and forward directions, but the ribbon feed was one-way. Damned clever.
Thanks for the video, i have a recumbent tricycle from 1985 and i had no idea how the drive works like magic but i looked at the bearing of the drive wheel and its a clutch bearing like this but its more like an inch wide.
Every time I watch one of your videos, I never fail to learn something
Good explanation on that type of bearing. Now lets see one of those fancy roller ratchets. We use light weight 1/4 inch roller ratchets to tighten hi-lite fasteners on aircraft.
These kinds of bearings are found on the front-end ball returns in some bowling centers. I was a mechanic on bowling machines for 45 years. They worked flawlessly for years, then would suddenly fail (no longer engaging).
I once worked for a guy who thought he would make them last longer by packing them with grease. The balls would no longer shift, and the clutches would no longer engage. I had to replace all 24 of them (48 lane center) one night because they all shut down, and the league could not bowl.
There's a sprag on my motorcycle's clutch. I wondered how it works. Thanks!
Excellent description mate.
Thanks AVE. I understood the basic function but now I know it in detail. Thanks Bud I appreciate you. P.S. and the Deuxclaw.
Awsome upload!!! Love your work!!!
I've been curious about this for a while
Just got learnt about these in class, neat timing!
The mountain bike industry is starting to implement systems like these into their freehub bearings for silent performance. I've always been curious as to the point where it might slip or wear prematurely compared to traditional freehubs. I'd love to see you compare and disassemble some freehubs such as the i9 torch and perhaps the new Shimano XT silent freehubs.
you should reverse the old video cull. how are people supposed to know what not to do if they can't see you do it?
I agree with you
I agree with you
@@Caltevir deleted?
@@Caltevir I went to your link and the page has been deleted
I found those also in the pulley of the alternator drive. It is in constant bind when engine is spining. When stoped it allowes the alternator to spindown for shortwhile. Or for sudden deceleration of the engine it maintains the speed of alternator.
Very well explained and illustrated. Thank you.
Neat that it fits the the space of a typical bearing. Did not know it existed. Doesn't seem very elegant through.
You will find these one way sprags throughout all kinds of automatic transmissions today. Both types are used.
They were always popular in the starter bendix drive as well.
In a manual transmission auto clutch 3 wheeler or quad, a sprague clutch is often used in a drum style centrifugal clutch- to allow the machine to idle in gear but still have engine braking. A separate motorcycle style multi-plate clutch is often used, which disengages as the shift lever is moved away from the center detent, allowing the transmission to unload and shift at higher rpm.
An easy place to find a sprag clutch is on any pull-start engine. It grabs the crankshaft when you pull, and doesn't when the rope goes back. Unless it's broken. Then the engine will forcibly rewind the rope backwards, and break the handle off.
Many (too many) moons ago I was an engineer with Canon. Print engines have a lot of one way clutches. The mechanism of choice was a spring which wrapped tightly around a shaft in one direction but was opened up, and hence free wheeled in the other direction. This was often used in such a way that an integral gear caused another shaft to turn when the shaft in question turned one way, but to allow the first shaft to turn independently the other way.
There's often a latch so that the first shaft might have to do a complete rotation before the clutch is re-engaged in the other direction.
When your printer picks up a blank sheet and it feeds in and out a short distance a couple of times to find the top or bottom edge, this arrangement is what stops another sheet being picked up at the same time.
We had one way bearings on our edger feed rolls, for anti kick back.
There are also needle roller oneway units. These oneway bearings are found in R/C helicopters where they're used to allow the heli to autorotate if the motor/engine fails.
I like the tip and just for minute, hell I like the long vajyos. Hell I like anyway you put out. Never had the chance to lay my highballs on a pair such as shown pretty cool.
I love sprag clutches, I have an automatic Husqvarna dirtbike that has a bunch in it. Cool little items for sure.
Ave....Have never seen this before well done!
Good interesting VJO
The one way roller bearinga are used a lot in photocopiers especially in the document feeder where the initial feed is quite slow up to the registration roller forming a buckle to straighten the sheet then the registration roller takes over and the one way roller clutch/bearing freewheels so the initial feed leave little resistance to the document you are wanting to copy.
Well you learn something new every day
First time I encountered one of these as a young hospital maintenance worker was when I got "assigned" to go to the home of one of our staff doctors to fix his wife's exercise bike. You could pedal the thing (the bike, not the wife), but every few turns the thing would slip, causing you to do a little quick-foot routine. Bearing was inside a pulley and allowed you to pedal forward, but would freewheel when you stopped.
Thank you for this !!! I've seen and replaced these before, and just never bothered to take one apart. *DUH!*
Always learn something from these videos. Thanks AVE ;-)
The starter dive for virtually every car and truck 1 on the planet has a 1 way clutch bearing in it. Starter clutches generally used roller bearings that jam one way and roll in the opposite direction.
Uploading like a Beast.
These are used on RC racing cars where they lock under power and freewheel when unpowered.
Pretty sure on our RC cars they were roller versions, though and tiny by comparison - 6mm shaft.
They were to accommodate two gears on one shaft whereupon after the gear change, the other gear would free wheel.
Also, on the front axle, one was used on each side instead of a differential . . worked kinda like a LSD and the car would bolt out of corners like a scalded cat - four wheel drive cars.
Used this kind of bearing on a bowling machine. 2 machines shared one ball return mechanism, and the idea was that when one machine was running it would pull on the shared shaft, and the side that was not on, would frewheel, making it possible to have a shaft with 2 input's but one input would not have to drive the other.
Those were a lot bigger than this one and also they were roller-pin styled, but the function was the same.
Holy shit, _that's_ how drill clutches work.
Thank you, AvE!
Pretty cool idea. Shimano reels use a similar technique but they use roller bearings in a cage with springs for tension in the races. What is "really" cool is they made it switchable. You can turn off the anti-reverse.
Thanks uncle BF learned something i didn't know i needed. Info stored for later.
I have always wondered about that. Thank you sir.
I owned a 1948 landrover gearbox which had a roller sprag for four wheel drive (only going forward) The centre ramp was a three sided star cam thing and each one had a daddy’s, a mummy and a baby roller. So nine rollers in the clutch. It used to jump like jackhammer :D
I like how you splashed out with a diagram. Top effort.
I just learned about one way needle bearings on an old warn bellview winch, if you put them in backwards you get a nice hand warmer and smoke machine and the worry that you'll need a hard to come by electric motor that looked great when it was on the healing bench 5 years ago
Great stuff as usual
Great little info-vgo.
Steno machines and B&H equipment from the 20's to the 60's (and in one case till 1972). used a different (early) design clutch. These were made up of loose parts under a sheet metal cover inside a cast and machined pulley. A big cam and a spring inside would allow the pulley to run freely in one direction but would lock if pulley tried to change direction. All of this was done with loose tiny parts (trapped loose ball bearings, etc.) that had to be removed to access a regular needle (roller) bearing for service (also made of tiny loose parts). They both switched to miniature one-way clutch bearings when these became readily available in the 60s. They also replaced the pulley bearings with regular needle bearings.
Unfortunately, the newer design would would fail when the grease they used dried up. Then the bearing side of things cease rolling and just become a static surface that the shafts would spin in, essentially becoming a solid bearing. If not caught early the friction would cut into the shaft, especially with the simple needle bearings. Failure of the one-way clutch would immediately be noticed as it would cease its ratchet-like action. A lot of sprocket and platen assemblies were destroyed this way. If caught in time the fix was simple: clean and re-lube the bearings with a lighter lubricant, usually medium weight oil. In some cases the one-way bearing would need replacement.
In later design equipment they put the one-way bearings in plastic (nylon) gears. These would fail quickly in service either from the bearing slipping in the plastic under load, or the plastic shrinking microscopically and cracking, freely allowing the bearing to slip. They addressed this by using a wide one-way bearing in them, spreading the load over bigger surface area.
Nowadays these little wonders are everywhere and waiting to screw you at the worst minute. RC hobbyists have learned to service them every 10 flights or so to avoid destructive failures, etc.
Washing machines have these! I had replace mine when I fixed my washer/dryer.
Sprags are used in the AH-64 Apache to prevent back driving of the drivetrain. They're a sight more sophisticated than this, but same idea. Great vid, uncle BF.
That was enlightening. Thank you sir 👍
In printing its not to stop the shaft from reversing, but to let the next set of rollers be able to convey the paper while the drive of the previous roller is disabled. Even when the speed of the previous conveyance roller is slower than the next the paper will be pulled by the next set faster than its fed, the bearing spins free and faster than the shaft. In this application its called not a bearing but a clutch.
This knowledge is more useful then most of the classes I took in school
I had a few of these as hand me downs from a friend that works in industrial design (planning factory floors and all that jazz) and for ages, i couldn't understand why it only went one way. It didn't make sense to me because it looked the same as a normal bearing. Took the cover off come to find some mechanical wizardry inside using cam rollers (unlike this one) and a sort of pattern in the cam roller's holder. Likely, not meant for heavy duty action, seeing as there was plastic and no keyed shaft.
Back in 1804 a famous inventor from Greenland tried to turn a Sprag Clutch in the non-rotational direction, and found she could not. She wrote to some associates in what is now Croatia, proclaiming the supposed "bearing" "unbearable", thus coining the word we now use to describe an unpleasant situation. True story.