one way clutch , reliability and rpm and torque handling?

[88FieroGT]

What are the best one way clutch types to use for REPEATED force , opposite force loads?

for example spin clockwise for lockup at 6000rpm and say 200lb ft of torque , and then switch to a 6000 rpm counter clock wise which is where it will freewheel at 6000rpm... basically a 12000 RPM spectrum

back and forth , basically engine and disengage every 180 degrees of revolution

are one way clutches durable , can they handle that kind of power and torture in a practical size?

[88FieroGT]

Access forbidden!

that link is to a nasa study about one way clutches for military application testings that I stumbled on.

got a little info as far as in excess of 500,000 cycles at max load of 875 with that particular one , but that equals out to less than 1.5hours at a constant 6000rpm for my application. But the torque difference is probably around 4+ times the maximum I picture exerted so still no idea how long it would last.

Also I think the testing methods said with limited oiling. But also cycles were farther apart than 100-200 cycles per second I think there testing wasnt even in the teens. Unsure if its feasible for my engine application....

I have 2 other ideas, one I have tried in a physics program and showed a promising 20-40% efficiency gain with just eyeballed tolerances and engineering so I expect that to be around the ballpark if not higher.

I have started to stumble upon similiar engine designs although not identical and far more complicated than they need be also. So I may not even after getting working prototypes be able to do anything with them.

[wmjinman]

Sounds like pretty severe duty to me. - if I understand what you're saying; 6000 rpm is 100 times per second. And you want this thing to change direction TWICE per revolution, right? So that means 200 "reverses" per second? So that would be moving at the rate of - say - valves in a 12,000 rpm engine? - or the injectors operating? But with much higher loads, right? What else? I don't know...

[88FieroGT]

Sounds like you understand what im trying to figure out. However due to valves opening and closing all the way each half revolution of the crankshaft during their operation the spectrum would actually be a 24,000 with no torque load really applied. comparing to pistons would probably be a better comparison since it has the same spectrum at 6k rpms and also load.

I have a design invention that would drastically improve on efficiency but want to make sure it will be reliable enough to be used , even if it turns into a maintanance item so design setup to make an easy swap but I dont see life time less than 150-300 hours being practical what so ever. I have other ideas which I can use in place but this I think is the best setup.

[88FieroGT]

But yes , severe duty is right.... just wondering if it would be possible to hold up at a practical size... I dont want a clutch thats bigger than a foot in diameter to transfer the loads.

Its for an engine build , and the bigger the clutch is , the bigger the overall engine design is and I dont see a huge , heavy , but extremely efficient engine being good. When I can use another idea to do the same principle

[justme1969]

without any specifics given it sounds like your direction may need to be hydraulics

[razor02097]

Sounds like you are looking for a giant motorcycle starter clutch... The basic principle is like this...



The strength would depend on the materials, size of the components, and how many bearings you are going to include in your clutch.

[88FieroGT]

exactly but this is extreme cycle abuse unsure of what the actual displacement the clutch will be abused from and how many rpms , I just know that since its almost 2x as efficient output torque will be equal to a normal engine with half the displacement with redline is the same if breathing allows it

it switches from disengaged to engaged and engaged to disengaged a total of 12000 times at 6000 rpms with combustion torque. can these clutches whether sprag or ball bearing actually hold up to that much cycle abuse

cause at 6000rpm if thats considered peak power in the engine would end up being 6000 cycles in 1 minute and from ones I have seen that actually list the cycle life is only like 500,000 cycles which would only last 80-90 minutes total redline abuse before maintenance is required not including sub redline wear.

I am just wanting other peoples opinions as to whether it could hold up in a normal power rated engine for a considerable enough amount of time to actually say its worth using in my design and the clutch wont end up being TOO big to be used inside of an engine at the point where it can handle the abuse. Like say its a maintenance item thats required to be changed every 10,000 miles sounds like the minimum plausible amount of time to me as long as the design can allow for easy quick replacement at a fair cost


Well actually thinking more about it , it doesnt have to be inside the engine it can be outside mounted to the rotating shaft so size can be bigger than I initially thought even though still has to be practical , engine size wont need to scale up to make them compatible by making a stronger clutch without having to increase engine displacement or change bore/stroke ratio. Just adds in an extra component is all , fair trade off..

[razor02097]

You wouldn't be able to rely on mechanical springs. You would either have to use a hydraulic method or charged gas to maintain the pressure on the rollers. All the springs do is hold the rollers to the point of bind so the clutch locks up as soon as the shaft changes direction.

A typical starter clutch is about as big around as a soda can and about 3/4" or 1" thick. They are strong enough to turn over a 1.3L motorcycle engine.

[88FieroGT]

from what ive been reading most starters for motorcycles have switched from a bendix drive to a sprag type of clutch , unsure about cars/trucks. What is the idle speed of the motorcycle compared to the starter for the 1.3L motorcycle?

and can you imagine that start being able to last freewheeling continually *starter engaged* while the engine is idling and reving , thats HALF of the kind of abuse it would have to be able to handle.

definitely agree about the springs not being able to handle the speed and cycle transition speeds they would be exposed to with the ball bearing type clutches