roller chain efficiency
roller chain efficiency
(OP)
It's generally conceived that roller chain typically have an
efficiency of around 98%. Out of all the different types of losses,
does anyone know which one is the most significant?
There are primarily:
1. Sprocket tooth/chain sliding friction (engagement/disengagement)
loss
2. Chain segment bending loss.
3. Bearing loss.
The joints in the chain are bushings. But is it possible to
substitute it with bearings? It may get larger and heavier, but what
if I need a chain that has the ultimate efficiency, but weight and
size are not as important? Can that be done? With bearings at the
joint, it should have a higher efficiency.
The sprocket tooth sliding friction isn't very big from what I
heard. This is because the chain segment interface is "free to
roll". You can literally touch the tooth interface on the chain and
rotate it with your fingers.
I need a chain that can get an efficiency of 98.5%. Can I replace the bushings in the chain with bearings?
efficiency of around 98%. Out of all the different types of losses,
does anyone know which one is the most significant?
There are primarily:
1. Sprocket tooth/chain sliding friction (engagement/disengagement)
loss
2. Chain segment bending loss.
3. Bearing loss.
The joints in the chain are bushings. But is it possible to
substitute it with bearings? It may get larger and heavier, but what
if I need a chain that has the ultimate efficiency, but weight and
size are not as important? Can that be done? With bearings at the
joint, it should have a higher efficiency.
The sprocket tooth sliding friction isn't very big from what I
heard. This is because the chain segment interface is "free to
roll". You can literally touch the tooth interface on the chain and
rotate it with your fingers.
I need a chain that can get an efficiency of 98.5%. Can I replace the bushings in the chain with bearings?





RE: roller chain efficiency
RE: roller chain efficiency
I would guess it is more of an upper limit than an average.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: roller chain efficiency
it's generally conceived that spur gear have an efficiency of 99%. Is that an upper limit or is that an average also?
Thanks
RE: roller chain efficiency
I normally use 98% for gearsets in good condition, but that falls to less than 90% in some (common) circumstances. designing gearboxes to work efficiently over a wide range of torques is very difficult.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: roller chain efficiency
htt
Maybe 10 HP on this pup. If the max power delivered is around 50 HP, then the how in the world can the "efficiency" ever exceed 80% ?
RE: roller chain efficiency
Also, there are two flavors of "Morse", Borg-Warner Morse who make the automotive chain and only talk to you if you want 100,000 pieces and Emerson-Morse that sell the chain for every other application but will sell single pieces.
RE: roller chain efficiency
It seems chain drives are usually single speed only. The only
multispeed chain drives are used on bicycles, and it uses the
derailleur mechanism.
But on motorcycles, industrial power transmission, conveyors, ect... it
seems to be single speed. I'm not sure.
Are there any non-bicycle applications that utilizes a multispeed chain
drives? Does it use a clutch or derailleur?
Thanks.
RE: roller chain efficiency
RE: roller chain efficiency
If by "single speed" you mean it does not have variable ratios, then you are correct, the same as a gear drive. Since the number of teeth around the sprocket has to be an integer and nobody has built phase shifting sprockets as yet, the only ways to change the ratio is by changing sprockets. Variable ratio belt drives trap a Vee belt between moveable conical plates, usually one spring loaded, the other mechanically driven. A lot of friction pulling the belt into the groove and pulling it out again.
Transmissions could use multi-speed chain drives but there probably is no advantage over a gear cluster. Heavier and more parts. Bicyces only transmit 1/3 HP or less. I suspect the latest 27 speed designs are close to a trade-off with a variable planetary system. The derailluer system has the big advantage of no neutral between gears.
RE: roller chain efficiency
Thanks
RE: roller chain efficiency
RE: roller chain efficiency
I believe earth moving trucks use hydraulic drive. through a planetary drive in the wheel hub.
RE: roller chain efficiency
RE: roller chain efficiency
RE: roller chain efficiency
Which type of loss is more significant for a chain drive?
1. Sprocket tooth/chain sliding friction (engagement/disengagement)
loss
2. Chain segment bending loss.
or are they about equal?
As a follow up question, can you tell me if the following type of analysis is valid:
a gear pair is inheritantly more efficient than a chain drive because there is only ONE teeth to teeth interface for a pair of gears. In another word, one gear can drive the other gear DIRECTLY.
A chain drive requires TWO interface. First the sprocket drives a chain, then, the chain drives a different sprocket. So in another word, a sprocket cannot drive another sprocket directly. Since there is 2 interface/steps, I think a chain drive (even those silent types) should be at least twice as inefficient as gears.
And that's not counting the bending loss at the links.
That means, if the gear pair has an efficiency of 99. Then the chain can not have more than an efficiency of 98. Of course this is assuming there is no bending loss at the links and the sprocket to chain meshing is just as efficient as the regular gear tooth meshing, which is unlikely.
Is that correct?
RE: roller chain efficiency
I don't know if you can make a power assisted derailleur work with a standard industrial chain, I'm sure the sprocket design is important as well.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: roller chain efficiency
An overrun clutch will be necessary to avoid the chain going slack on overrun
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: roller chain efficiency
Roller chain is not nearly as efficient as Morse Hy-Vo. The Hy-Vo chain experiences far less increase in friction with increased speed or power. All load bearing parts roll in place, no sliding. The "pins" are really two pins that are slightly "C" shaped and placed back to back. This makes for very long life with minimal lubrication. Very different from average silent chain found in transfer cases and cam drives.
Nothing beats a roller chain for long shaft center distance and low cost. Many big road graders are roller chain drive. Most street bikes, most cars, are silent chain drive. So was the PJ Indy Turbine car (Morse Hy-Vo).
RE: roller chain efficiency
Thanks
RE: roller chain efficiency
Thanks
RE: roller chain efficiency
RE: roller chain efficiency
Got another question.
You know when the roller chain is wrapped around the sprocket, theoretically the load should be shared across all the teeth on the sprocket. Theoretically.
I really doubt that's the case in real life. The chain and the sprocket are not machined to exact specification like gears so it's unlikely that the pitch of the chain will exactly match the pitch of the sprocket. Also, once the chain starts to wear and elongate, things get worse.
Therefore, I think maybe only one or two teeth is bearing the load at any instant. There will be a small "gap" between other teeth and their corresponding chain roller that prevent them to transmit power.
What do you think?
RE: roller chain efficiency
RE: roller chain efficiency
Thanks for the help Fabrico.
But I don't understand why the chain will wear and rides farther out on the sprocket if the joints "rolls" rather than slide. That means there should be essentially no wear or elongation. Or is there? Maybe it's not perfect rolling?
RE: roller chain efficiency
As far as no wear or elongation, they are close, but nothing is perfect. Roller and needle bearings don’t slide either but they do wear.
RE: roller chain efficiency
RE: roller chain efficiency
What do you think?"
I think that's why MC chain OEM's advise (and experience demands) that the chain & sprockets be replaced as a set- they wear complementarily and spread the load, but are never ideal whether new or old.
What about periodicity? If the chain length and number of sprocket teeth are matched so that the teeth always contact the same rollers is that better or worse for wear?
RE: roller chain efficiency
It is highly recommended that a "hunting tooth" ratio be used so the chain does not contact the same teeth.
Hy-VO chains are installed in what might be considered virtually permanent places, such as in the deep center of superbike engines, FWD transaxles, etc. They generally outlast the parts around them. I used some 3" wide 1/2" pitch 10 years ago and it costs $100 per foot.
RE: roller chain efficiency
RE: roller chain efficiency
Magnograil mentioned that Morse is difficult to work with for the little guy and he is right. Ramsey makes what they call the RPV line and claim it to be equivalent and fully interchangable with Morse Hy-Vo. http://www.ramseychain.com/prod_power_trans.asp