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Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 03:31pm 24 Sep 2011
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Hi Govertical,
Another optical illussion,the belts already look like they are mis-aligned and running at angles.I feel that implementing perry's suggestion will increase belt life considerably and having them aligned true reduces side shedding and negates belt runoff.Allowing a larger surface area allows the belts to stretch and retract randomly placing uneven forces on the tensioner.Defeating the purpose of keeping the noise down and even/consistant belt tension.My comments are only conjecture of course,I'll happily be proven wrong!Cheers Rastus see Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 12:52am 25 Sep 2011
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Greetings, project update:
Timing belts and pulleys are installed on a test rig. Because the pulleys are made using two pieces I was able to bevel each piece toward the center of the pulley. This forces the belts to track toward the center of the pulley so a lip is not required. I have to find the correct tool to bend the spring into the correct shape. This a first attempt but it appears to be working. The spring pulls on the top and bottom of the movable shaft and all belts have tension. Again this is a experiment and a learning experience, I do not know how long the belts will last. The next step is to mount it on the PMA and perform a road test. The current configuration is a 1 : 6 ratio.
Edited by govertical 2011-09-26just because your a GURU or forum administer does not mean your always correct :)
Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 224
Posted: 01:03am 25 Sep 2011
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A work of art.
Anthony. "Creativity is detirmined by the way you hold your tounge".My Father
"Your generation will have to correct the problems made by mine".My Grandfather.
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 02:55pm 25 Sep 2011
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If you mean that the center of each pulley has a slightly larger diameter by "bevel each piece toward the center of the pulley" then this would work for the old fashioned flat belts.
Toothed timing belts are constructed to run on a flat pulley, I'm not sure if what you did might also shorten their life as the load is taken at the center of the belt now.
My suggestion is to bite the bullet and fit shoulder disks, all those commercial toothed pulley makers surely could not be wrong .Klaus
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 06:31pm 25 Sep 2011
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Hi, the center of each pulley set is a slightly smaller diameter. Thanks for the suggestion if the current configuration becomes a problem I can add shoulders to the pulleys. The belts are only installed on a test rig and I am able to spin test the current configuration manually. When the shafts are parallel the belts track to the center of the pulleys. The belts are very quiet and the units spins very easily compared to the gears that I was trying use. I am surprised how well the timing belts grip the pulleys. I hope to be able to perform a road test within the next week. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 04:48pm 30 Sep 2011
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Greetings, the 3/8 timing belt is just to small for the intended application. Even under tension the belts would skip the pulleys at higher RPM’s. I was able to find larger tooth V belts at the local auto parts store. They are a larger diameter with larger teeth. This should resolve the problem. I have to fabricate new pulley. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 01:50pm 01 Oct 2011
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That belt looks very much like an ordinary 'Vee' belt used on alternators. It is not meant to run on a toothed hub at all, just in a Vee groove. I think the 'teeth' allow the belt to flex more reliably on small pulleys.
You would do much better to look for automotive flat belts with either teeth or several longitudinal Vee grooves on the inside. These are designed to transmit high power loads. Even some Harley Davidson bikes use a toothed belt drive to the rear wheel.
Have fun. Klaus
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 04:19pm 01 Oct 2011
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Greetings,
The belts are very flexible and I am able to fabricate a notched pulley that should prevent the belt from slipping. The new pulleys will have a lip that will keep the belt on the pulley. Thanks for all the help I am receiving, enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
grub Senior Member Joined: 27/11/2007 Location: AustraliaPosts: 169
Posted: 10:46pm 01 Oct 2011
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govertical, you could make two angled side plates to go on your notched belt pulley so that your pulley becomes a vee pulley. This would help keep the belt on the pulley along with any other vee pulley benefits.
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 07:15pm 02 Oct 2011
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Greetings, milling notched pulleys. It will be interesting to see how long the belts will last. Fabricating pulleys using two pieces, each side will have a lip to contain belts. Current ratio is 1: 7. Enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 01:51am 05 Oct 2011
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Greetings, just some photos of the 1: 7 synchronous belt drive transmission on the test fixture. I have to add spring loaded bolts to apply tension to the belt pulleys on the movable shaft.
just because your a GURU or forum administer does not mean your always correct :)
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 10:32pm 05 Oct 2011
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Greetings, I completed the spring loaded bolt mounts to maintain a constant tension on the belts. The springs pulsates when I spin the rotor. This is showing that the pulleys are not prefect circles or the belt is riding up on the pulley teeth or a combination of both. This is a problem that will have to be resolved. It does work well enough for a road test. Comments welcome.
just because your a GURU or forum administer does not mean your always correct :)
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 12:11pm 06 Oct 2011
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Movable shafts are fine, IMO, to preset the belt tension. The moving part is then locked securely.
Having the shaft moving all the time against a spring is, IMO, not a good idea.
Its heaps better to have individual spring loaded idle roller tensioners on each belt.
I'm speaking from what I have observed during my working live on successful machinery.
It may be wise to imitate what others have found out the hard way long ago instead of trying to reinvent the wheel so to speak.
But I can see you are having lots of fun and will no doubt learn a lot along the way to make the perfect wind generator RPM increasing gear set up.Klaus
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 05:55pm 06 Oct 2011
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Hi, earlier designs did not have the space to place a idler pulley on the side because there were just to many belts. I saw the spring idea used on early turn of the century machinery and thought I would give it a try. Using just two belts there is now enough room for the idler pulleys to be mounted on the side. It is a better idea and will be included in the next modification. Thank you. I have to round off the teeth on the pulleys because the belt is riding out of the grooves and causing a pulsation during rotation. After the modifications the problems should be resolved. Thank again and enjoy the day.
just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 07:58am 07 Oct 2011
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Hi Govertical,
There seems to be to many springs to compound the proplem.Remove the mount bolt springs and bolt up solid against the tyne spring tension.I hope that will stop the bouncing you are getting.Cheers Rastussee Rastus graduate advise generously
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 01:09pm 07 Oct 2011
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Hi, when I made the pulleys I did not have the tooth pitch and tooth spacing of the belt that I am using. I have to make new pulleys with correct size teeth. I am searching for the design specs for a Dayco 10A0775 automotive v-belt. Once the pulley teeth are in the correct place the problem will be solved. I emailed the company but if anyone knows how I can find the design specs for the belt please let me know.
Edited by govertical 2011-10-08just because your a GURU or forum administer does not mean your always correct :)
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 03:35pm 07 Oct 2011
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i would be very surprised if dayco responds at all. It is an automotive V-belt not a toothed belt. the cogs are not designed to touch anything just flex. There is no load bearing structure inside the "teeth" the belt will not sit upright under tension and with a driven load the cogs will just tear off.
the belt is designed to be driven by its sides at the line you can see the fibre spine by a pulley like this.
if you have ever heard an old car with a badly squealing fan belt, air-con belt or power steering belt it is usually because the VEE in the pulley is worn to a U shape and the belt is bottoming out in the pulley, no amount of belt tension will help this.
V pulleys are not that hard to build if you can chamfer the V belt angle on 2 plates, they can be bolted together with spacers and shims to get the correct width.You could probably do it with your current pulleys. Could you do the little pulleys first and try it? they are the ones that get hammered. I'm confused, no wait... maybe I'm not...
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 07:17am 09 Oct 2011
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Govertical
these can be quite effective for a bit of prototyping
Its called a variable pitch pulley, if you live in a drier region they will be on your local hardware shop's shelf for about $8, $12 if you want one with a key-way. It is used for adjusting the load on the electric motor of an evaporative air conditioner.
Just back off the allen key, wind one sheave in or out on the thread, line the allen key up with the flat and re-tighten.
With an "A" section belt it adjusts from 2 inch to 3 inch diameter, about 30 % speed change. They are capable of 2 horsepower. It pays to lube the thread with a graphite grease so it adjusts easily but even then the spring loaded tensioners may cause colourfull language
regards yahoo I'm confused, no wait... maybe I'm not...
govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383
Posted: 12:32am 10 Oct 2011
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Hi, the pulley teeth are now more likes waves. Thank you for all the help I am receiving. Basically it shows I can fabricate the needed pulleys. Because of the resizing of the pulleys the ratio is now 1: 5
just because your a GURU or forum administer does not mean your always correct :)
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 11:48am 10 Oct 2011
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Hi Govertical,
You've manufactured another quality component.How did you decide on the pitch of the "teeth".The picture shows the belt partially compressed around the gear.I think the belt will ride in and out of profile at different stages of drive and could leave you with the problem that prompted this alteration.I hope you'll accept my comments as observations not criticism.To my knowledge the belts are toothed for durability by reducing the repetitive compression (around the pulleys) and exspansion (straightening out) in opperation.Cheers Rastus see Rastus graduate advise generously
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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