genevive51
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| posted on 10/7/10 at 12:43 AM |
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Drive couplings
I am thinking of putting one of these couplings between my engine and sierra differential. Looking at the spec I think I can get one that will take
the torque and the rpm. I'm thinking it would allow for a certain amount of misalignment between the two units without them ripping each others
bearings apart. Has anyone any experience of them? Or can anyone think of any reason why I shouldn't use one, please see the link below, thanks
Nigel
http://www.jbj.co.uk/spidercouplings.html
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Canada EH!
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| posted on 10/7/10 at 01:17 AM |
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Designed more for electric motors in heavy duty torque situations, but unfortunately not for high speed applications.
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StrikerChris
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| posted on 10/7/10 at 01:38 AM |
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I wouldn't worry about them failing,have hundreds in work and rarely have to change the rubber.as already said tho,they only run 1500rpm at
work,and are heavy so upping that balancing could become an issue
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StrikerChris
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| posted on 10/7/10 at 01:45 AM |
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Ps early disco's have a rubber coupling between rear diff and prop similar to Imp driveshafts that outlast most landy gearboxes,might be worth
looking at.
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Mal
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| posted on 10/7/10 at 05:55 AM |
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The style of coupling you are thinking of using is normally fitted in applications such as a pump and motor where both flanges are in a fixed
position. If you want to use the coupling with a type 9 gearbox with a sliding spline you will need to limit axial movement so it cannot come apart.
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turbodisplay
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| posted on 10/7/10 at 07:46 AM |
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why not fit a cv joint, lobro type.
Will give 20mm back and forward movement.
2 will be required for mis alignment though.
Darren
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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genevive51
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| posted on 10/7/10 at 08:33 AM |
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Thanks for the replies folks, unfortunately I can't use a doughnut because I have only about 120mm diameter to play with at the bike output
shaft and I need to keep the diff as close to bike engine as I can. A CV joint is a thought though. What is a type 9 diff? I thought my diff had a
fixed input flange but I'll check later on. thanks Nigel
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hillbillyracer
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| posted on 10/7/10 at 09:07 AM |
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Looks like rpm is'nt an issue, they do couplings capable of 19,000rpm which even for a bike engine would be knocking on a fair bit!
If you had a solid dummy coupling to fit while you make the brackets up that bolt engine & diff in place you'd have minimal mis-alignment
& that would help the coupling last.
What would need looking into is how these couplings will cope with the on-off load of gearchanges etc, I think they're mabye more for constant
load jobs. But if it needed a new rubber spider every once in a while how bad would it be, I'm thinking you're not going to be doing a
high mileage?
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40inches
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| posted on 10/7/10 at 09:15 AM |
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quote:
Originally posted by Canada EH!
Designed more for electric motors in heavy duty torque situations, but unfortunately not for high speed applications.
From website "Maximum shaft diameters of 145 mm can be accommodated with maximum torques up to 15,000Nm and maximum speeds of 19,000 rpm"
Am I reading this wrong?
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genevive51
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| posted on 10/7/10 at 10:40 AM |
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Yea, I know, we use these in work but only on slow running equipment. Looking at their website I can do around 9000 rpm with 160nm torque on a
coupling about 100mm in diameter. this would be ideal for me. Bear in mind that 9000 rpm on the output shaft is about 10000rom on the engine in top
gear which even with a 3.9:1 diff would be probably about 130mph on 13 inch wheels, don't think it will reach that speed too often!!!!!
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Litemoth
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| posted on 10/7/10 at 02:40 PM |
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Just a thought, I've worked with these (between a motor and hydraulic pump seems a popular application) and there they experience pretty
constant speeds and loads. when they start to wear, would the 'lash' not be a problem? - on take up and overdrive? This isn't a
problem on fixed load/speed applications of course.
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MikeRJ
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| posted on 10/7/10 at 04:23 PM |
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The shafts need to be supported either side of these couplings - as some one mentioned they often sit between a motor and a pump or other equipment
and aren't connected to long unsupported shafts.
A CV joint would need a very heavy duty gaiter to survive prop shaft speeds...
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hillbillyracer
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| posted on 10/7/10 at 06:36 PM |
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quote:
Originally posted by MikeRJ
The shafts need to be supported either side of these couplings - as some one mentioned they often sit between a motor and a pump or other equipment
and aren't connected to long unsupported shafts.
A CV joint would need a very heavy duty gaiter to survive prop shaft speeds...
True on both points but I'm thinking he's going to have the diff bolted to the engine & just needs a coupling to connect the drive, no
shaft.
And yes, the rubber boot on a C.V. used in a prop is kind of inside out within a metal sleeve, I've never thought till now why but as you
suggest it'll be to cope with the centrifugal force stretching the rubber.
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genevive51
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| posted on 10/7/10 at 10:52 PM |
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Yea, you're right Hillbillyracer, there will be no drive shaft. Just the bike output shaft connected to the diff flange, thanks Nigel
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