woodsy144
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| posted on 27/11/19 at 10:04 PM |
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Chain Tension / Idle Gear
Hello Guys,
Ive been looking at the diff mounting, chain tension arrangement etc.
One though was to fix the diff and use an idle gear / wheel.
I found these online.
http://www.tcbroschoppers.com/weld-on-chain-tensioner-530-sprocket.html
Thinking is, by using this I can increase the wrap around the engine gear while maintaining chain tension.
No need for diff movement.
Any experience with these?
Thoughts?
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Mr Whippy
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| posted on 28/11/19 at 12:06 PM |
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Very common things, don't know where you are located but you can get them in the UK too, ebay sells loads of them. Usual use is to prevent the
chain flapping about, you even get them for push bikes, my recumbent trike also has one.
Personally I'd only use them on the return side of the chain since that has the least tension but yeah should work perfectly, make sure the
bearing is good quality an is easy to replace.
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nick205
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| posted on 28/11/19 at 03:09 PM |
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No personal experience with chain driven diffs, but I can't see an issue with the part. Engines that run timing belts have tensioners and
I'm sure many that run timing chains also have a tensioner as well.
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Mike S
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| posted on 28/11/19 at 04:20 PM |
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Hi
Chain tensioners are fine when the load is in one direction only, such as in cam chain applications etc. where the tensioner is in the unloaded side
of the arrangement at all times.
The problem with spring tensioners in transmission applications is that the the load direction changes (e.g. on overrun and engine braking) the
tensioner is then on the load side, compressing the spring and the spring and idler then have little effect, and the chain goes slack.
I think the idler gear for adjustment is a sound one, but it IMHO, should be solidly mounted rather than sprung. It would still be possible to have a
mounting arrangement that gave the adjustment so a solidly mounted idler could be used as the chain tensioner for a solidly mounted diff etc.
Cheers
Mike
[Edited on 28/11/19 by Mike S]
[Edited on 28/11/19 by Mike S]
There are more horses' asses in this world than there are horses
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jonny007
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| posted on 28/11/19 at 08:13 PM |
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Other option could be to fix diff but pivot the engine around front mountings with turnbuckle adjustment at rear to adjust tension.
Like the idea of solid mount though as above and could also be used to supply reverse drive.
[Edited on 28/11/19 by jonny007]
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woodsy144
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| posted on 28/11/19 at 08:50 PM |
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Some really good points.
With respect to the spring. It may raise issues as you mention. I was also thinking of running the reverse gear off the engine sprocket like the AB
performance kit, using the spring tension-er may cause issues cause thats now the drive side.
Could you use a motor on the idle gear as the reverse? I had not thought of that to now.
My only concern is when the running normally which will be 99.9% of the time the motor will be spinning. Power will be generated but in wrong polarity
to which it is wired.
Is there a motor with a one way bearing or slipper clutch to only work in one direction, maybe. But definitively worth considering.
Mount the motor arrangement on a cam arrangement and that is the chain tension-er.
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jonny007
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| posted on 28/11/19 at 09:10 PM |
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I'm not sure Id have the motor permanently fixed to the idler, it would normally be free to rotate but you could easily then engage on cable or
solenoid switch.
I'm looking at starting another BEC project so interested in others ideas. Maybe a motor in there as a hybrid is a further option assisting
engine at low speed to boost torque...
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woodsy144
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| posted on 28/11/19 at 09:17 PM |
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quote:
Originally posted by jonny007
I'm not sure Id have the motor permanently fixed to the idler, it would normally be free to rotate but you could easily then engage on cable or
solenoid switch.
I'm looking at starting another BEC project so interested in others ideas. Maybe a motor in there as a hybrid is a further option assisting
engine at low speed to boost torque...
Yeh free rotation would be idle, how to make that work is the head scratcher. Electric motor assist at low speed would be of assistance. Interesting
thinking. once again, something to keep me up at night.
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Mr Whippy
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| posted on 29/11/19 at 07:59 AM |
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quote:
Originally posted by woodsy144
Is there a motor with a one way bearing or slipper clutch to only work in one direction, maybe.
something like this on the motor? a bit like a push bike...
linky
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motorcycle_mayhem
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| posted on 29/11/19 at 09:36 AM |
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The ADR 1000 had a chain tensioning jockey wheel, so searching that might help (or even speaking to ADR). Chap in the South West had one, failed at
Castle Combe in the year that I saw it, probably underwent some sort of modification since it seemed to be generally problematical. Some of the
off-road things use a tensioner jockey, in fact DRD probably have a suitable sprocket with a bearing in their shop somewhere.
A different thing - controlling chain slap on an extended swing arm, has seen a spring and jockey sprocket arrangement. Some folk have used skateboard
wheels as an alternative. I wouldn't contemplate such a thing for tensioning, but if you're trying to tie up a long chain run it looks a
good idea, certainly quiet. I've used a cam chain guide to do the same thing, with good results.
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