tiltmaniac
Zen MBB Master
Surely it won't take that long to finish! 
Adding crazy tilt assembly... but to which frame?
- Thread starter tiltmaniac
- Start date
Martinius Berg
Active Member
Tiltmaniac
I love your creativity and your innovative work I think i understand which forces that damage your aluminium bracket setup ? When your rear wheels are tilting straight up and down one at the time pressure towards the balancing bracket and levers increases . I recommend that you check if the adjustable levers are in the exact same position and if the balance bracket holes are centered with the exact measures towards the frame centre point of your bike frame attachment ? One of the wheels will drag in the wrong direction if it is not adjusted neither centered the right way !
Awesome trike Martinius
I love your creativity and your innovative work
I think i understand which forces that damage your aluminium bracket setup ? When your rear wheels are tilting straight up and down one at the time pressure towards the balancing bracket and levers increases . I recommend that you check if the adjustable levers are in the exact same position and if the balance bracket holes are centered with the exact measures towards the frame centre point of your bike frame attachment ? One of the wheels will drag in the wrong direction if it is not adjusted neither centered the right way !Awesome trike Martinius
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tiltmaniac
Zen MBB Master
Martinus--
Thanks! It is a fun project to do, and even more fun to ride!
Preface: I'm not a structural engineer, and may have made mistakes. If you are a structural engineer, feel free to point out any mistakes!
The basic reason it is failing right now, as far as I understand it, is that there is ~100lbs of force on the rear from the weight of the rider, which gets magnified by about 8x by the arrangement, which then is concentrated on a tiny itsy-bitsy area where the cam and cam follower come into contact.
According to Hertz theory, we can compute the amount of pressure given the radii of the cam and cam follower and a few other parameters.
Without boring with a lot of math, in the first prototype, this maximum pressure comes out to about ~190,000 psi, which exceeds the strength of the material... by a lot (the yield strength of 6061 is ~16,000 psi)!
So, the obvious things to do are to:
Change the material (use steel which has a higher yield strength),
Lower the mechanical advantage of the system (i.e. increase the height of the tab to which the ball-end is attached),
Increase the height of the cam and cam follower
Increase the diameter of the cam follower (helps up to the point that height of cam and the height of the cam follower are equal).
Add a shock absorber to help handle bumps (it absorbs the pressure instead of the cam).
Anyway... that is likely what is happening with rev #2!
Thanks! It is a fun project to do, and even more fun to ride!
Preface: I'm not a structural engineer, and may have made mistakes. If you are a structural engineer, feel free to point out any mistakes!
The basic reason it is failing right now, as far as I understand it, is that there is ~100lbs of force on the rear from the weight of the rider, which gets magnified by about 8x by the arrangement, which then is concentrated on a tiny itsy-bitsy area where the cam and cam follower come into contact.
According to Hertz theory, we can compute the amount of pressure given the radii of the cam and cam follower and a few other parameters.
Without boring with a lot of math, in the first prototype, this maximum pressure comes out to about ~190,000 psi, which exceeds the strength of the material... by a lot (the yield strength of 6061 is ~16,000 psi)!
So, the obvious things to do are to:
Change the material (use steel which has a higher yield strength),
Lower the mechanical advantage of the system (i.e. increase the height of the tab to which the ball-end is attached),
Increase the height of the cam and cam follower
Increase the diameter of the cam follower (helps up to the point that height of cam and the height of the cam follower are equal).
Add a shock absorber to help handle bumps (it absorbs the pressure instead of the cam).
Anyway... that is likely what is happening with rev #2!
Martinius Berg
Active Member
Tiltmaniac
What about using a thick plastic/nylon/kevlar inforced material instead of aluminium or steal? The material i am thinking of is strong but light in weight but still flexible , easy enough to drill holes into and easy to shape it the way you want it ! Someone that could 3 D shape your parts in a CNC machine would not be to hard to find . Extra Shock absorbers sounds like a very good solution but remember that the angle of the absorber must be right and it can't be to heavy
Shapeways 3D printing website is a possible resource you could use ?http://www.shapeways.com
Good luck and keep me updated , thanks for sharing Martinius
What about using a thick plastic/nylon/kevlar inforced material instead of aluminium or steal? The material i am thinking of is strong but light in weight but still flexible , easy enough to drill holes into and easy to shape it the way you want it ! Someone that could 3 D shape your parts in a CNC machine would not be to hard to find . Extra Shock absorbers sounds like a very good solution but remember that the angle of the absorber must be right and it can't be to heavy
Shapeways 3D printing website is a possible resource you could use ?http://www.shapeways.com
Good luck and keep me updated , thanks for sharing Martinius
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tiltmaniac
Zen MBB Master
Martinius--
I've considered using some kind of other material for the cam as well, and may try it, but suspect that it would either break quickly, or would cause resistance to tilting at any tilt angle, which would be undesirable.
I've considered using some kind of other material for the cam as well, and may try it, but suspect that it would either break quickly, or would cause resistance to tilting at any tilt angle, which would be undesirable.
tiltmaniac
Zen MBB Master
Sorry for the lack of updates. Due to dealing with new kiddo, I've had no time to work on the project other than riding prototype #1 around.
Charles.Plager
Recumbent Quant
Congratulations! We'll accept delays because of addtions of new members to the Cruzbike tribe.
tiltmaniac
Zen MBB Master
The project still lives, though there has still been no real progress except some additional CAD models.
Danny Clarke
New Member
My tilting delta is a little different. For some reason I am not allowed to post a picture. C'est-la-vie.
It is a work in progress. It has differential tilt as a feature (inside wheel always tilts more in a turn).
It is a work in progress. It has differential tilt as a feature (inside wheel always tilts more in a turn).
MariposaLand
Active Member
I can see the functionality of such a device if you will be able to travel very slowly and even stop without unclipping. Otherwise balance is a function of time in the seat. Good luck with your innovative project @tiltmaniac
Roger Underhill
Member
CB have had a prototype like this for a few years. There’s a YouTube video of Maria riding it somewhere. Still a great project!
