Naked Science Forum

General Science => General Science => Topic started by: neilep on 28/10/2006 19:38:43

Title: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 28/10/2006 19:38:43

Is there no room for improvement on the shape of the car tyre ?....why not have them ball shaped ?...it would make for very good turning circles and sideways movement joy ?


Just a thought!!

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: ukmicky on 28/10/2006 19:48:39

If they were ball shaped how would you connect them to the axle ,gearbox and engine.

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 28/10/2006 19:52:46

Quote from: ukmicky on 28/10/2006 19:48:39

If they were ball shaped how would you connect them to the axle ,gearbox and engine.

Yep..me thought about that...Me just figured... ' what the hell '...some clever bod (not me obviously)......will figure it out !!

But..I am sure I have seen vehicles with this kind of wheel !!


YAYYYYYYYYYYY !!..it's just great to see Michael here !!!

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: another_someone on 28/10/2006 20:56:55

The tyres are not the issue, the wheels are.

As Michael said, one could not connect an axle to a spherical wheel.

On the other hand, are there other ways to transfer power to the wheel?

I would suggest that magnetic induction from outside the wheel, driving a metal sphere through induction by a phased induction motor could do it, but how practical it is, is another matter.

Ofcourse, one could see caterpillar tracks as a different form of wheel.

The problem with spherical wheels (apart from how you place pneumatic types on it) is that it may be substantially more difficult to drive the vehicle in a straight line (although easier to drive it in anything but a straight line).

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: eric l on 29/10/2006 10:42:46

One could take the (mechanical) computer mouse as an example.  Instead of the ball driving two sensor wheels, this sensor wheels would drive the ball, which could then make the ball (and the complete vehicle resting on it) move not only back and forth, but also left and right.  Imagine the ease for parkingin a street.

Actually, you get a good idea of why tyres are shaped the way they are when comparing car tyres to motorcycle tyres.  Car tyres have a more or less rectangular section, because a car remains more or less upright, and so you have always a flat contact patch between road and tyre.

Motorcycle tyres are more or less triangular or egg-shaped in section.  When the motorcycle is upright, which means moving in a straight line, you have a narrow patch of contact.  For cornering, you lean the motorcycle, and the contact patch becomes wider the more you lean.  This comes in handy to prevent the motorcycle from drifting through a corner.

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 29/10/2006 17:19:43

THANK YOU ERIC !


You invent it and I'll split it 50/50 with you (the profits that is...Not the tyre) [;)]

Thank you for the motorcycle/car tyre comparison too..very interesting !

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: iko on 29/10/2006 17:51:37

This is a good idea!

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.math.ohio-state.edu%2F%7Eedgar%2Fsquare_wheels.jpg&hash=71619f81bef5a3ca7a9813d37940e673)

http://www.math.ohio-state.edu/~edgar/square_wheels.jpg

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 29/10/2006 19:06:30

LOL..THANK YOU IKO,

I just do not understand why it never caught on !!....seems far more efficient than the silly round wheels.

 [::)] [::)] [::)]

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: ukmicky on 29/10/2006 20:35:22

Quote from: neilep on 29/10/2006 19:06:30

LOL..THANK YOU IKO,

I just do not understand why it never caught on !!.... [::)] [::)] [::)]

well being able to turn a corner would come in handy [:)]

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: ROBERT on 30/10/2006 14:05:22

Quote from: eric l on 29/10/2006 10:42:46

One could take the (mechanical) computer mouse as an example.  Instead of the ball driving two sensor wheels, this sensor wheels would drive the ball, which could then make the ball (and the complete vehicle resting on it) move not only back and forth, but also left and right.  Imagine the ease for parkingin a street.

" Ball-balancing robot refuses to roll over
Kurt Kleiner   
 
 (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi24.photobucket.com%2Falbums%2Fc23%2FSUEDONIM%2FBALLBOT.jpg&hash=01f5ca47130549696e32154258f35c9f)
 
A robot that balances on top of a metal sphere about the size of a soccer ball could be a model for more nimble android assistants.

The tall, thin robot, called Ballbot, sits on top of a ball, which it controls using a pair of rollers. Balance sensors feed information to an onboard computer. This continually moves the ball to make sure it is always under the robot's centre of gravity. Ballbot can also move in any direction, and regain its balance after a push, by making minor adjustments to the ball beneath it.

Two videos show the robot responding to being pushed (17.7MB, mpeg) and moving from one spot to another (19.8MB). "

http://www.newscientisttech.com/article/dn9720-ballbalancing-robot-refuses-to-roll-over.html

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 30/10/2006 14:19:13

AWESOME ROBOT ROBERT !!


Do they know where to send me my cheque ?

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: Karen W. on 30/10/2006 15:16:58

Would not different flooring levels ie stairs ect limit this robot to level surfaces...? I guess thats minor problem, but it's still cool!

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: another_someone on 30/10/2006 15:47:19

Quote from: Karen W. on 30/10/2006 15:16:58

Would not different flooring levels ie stairs ect limit this robot to level surfaces...? I guess thats minor problem, but it's still cool!

Don't think it is such a minor problem.

The human environment has been designed for things with legs - although increasing legal requirements for providing access to people without legs may also ultimately benefit robots without legs.

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: ROBERT on 31/10/2006 15:09:33

Quote from: neilep on 28/10/2006 19:52:46

..I am sure I have seen vehicles with this kind of wheel !!

Possibly James Dyson's Ballbarrow:-

" Ballbarrow

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi24.photobucket.com%2Falbums%2Fc23%2FSUEDONIM%2FBallbarrow.jpg&hash=e64709419af24e24bb50e36ccaeffe0c)

From Wikipedia, the free encyclopedia
 
The Ballbarrow was a type of wheelbarrow designed by James Dyson and released in 1974 in the United Kingdom. It used a ball instead of a wheel and had several benefits in that the ball did not dig into the ground like a wheel, steering was much easier and the plastic hopper was easier to clean than the galvanized alternatives."

http://en.wikipedia.org/wiki/Ballbarrow

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: iko on 31/10/2006 23:03:58

Initial efforts: tetherless planar motors
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.msl.ri.cmu.edu%2Fprojects%2Fcordless%2Fimages%2Fcordlesswheels01small.jpg&hash=cec1085870c99f1ad3c9435d842b8460)
http://www.msl.ri.cmu.edu/projects/cordless/images/cordlesswheels01small.jpg

 ...To eliminate the tether, power, electronics, communication, and bearing means must be incorporated in the forcer itself. Our first effort used 4 ball wheel bearings, onboard electronics, and wireless radio communication.

Here we have the smart "neilep2006" prototype
Isn't it a beauty?

ikod

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 01/11/2006 22:24:34

Quote from: ROBERT on 31/10/2006 15:09:33

Quote from: neilep on 28/10/2006 19:52:46

..I am sure I have seen vehicles with this kind of wheel !!

Possibly James Dyson's Ballbarrow:-


" Ballbarrow

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi24.photobucket.com%2Falbums%2Fc23%2FSUEDONIM%2FBallbarrow.jpg&hash=e64709419af24e24bb50e36ccaeffe0c)

From Wikipedia, the free encyclopedia
 
The Ballbarrow was a type of wheelbarrow designed by James Dyson and released in 1974 in the United Kingdom. It used a ball instead of a wheel and had several benefits in that the ball did not dig into the ground like a wheel, steering was much easier and the plastic hopper was easier to clean than the galvanized alternatives."

http://en.wikipedia.org/wiki/Ballbarrow

THAT is where I have seen it !!..THANKS Robert !!

Title: Re: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: neilep on 01/11/2006 22:25:24

Quote from: iko on 31/10/2006 23:03:58

Initial efforts: tetherless planar motors
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.msl.ri.cmu.edu%2Fprojects%2Fcordless%2Fimages%2Fcordlesswheels01small.jpg&hash=cec1085870c99f1ad3c9435d842b8460)
http://www.msl.ri.cmu.edu/projects/cordless/images/cordlesswheels01small.jpg

 ...To eliminate the tether, power, electronics, communication, and bearing means must be incorporated in the forcer itself. Our first effort used 4 ball wheel bearings, onboard electronics, and wireless radio communication.

Here we have the smart "neilep2006" prototype
Isn't it a beauty?

ikod

LOL ..THANK YOU IKO.....yep, I reckon that's smarter than me alright !! *hugs the Iko man*

Title: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: Strangemind on 26/07/2011 05:53:04

How would you turn corners. the front of the car would not change direction

Title: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: CliffordK on 26/07/2011 06:11:58

Quote from: Strangemind on 26/07/2011 05:53:04

How would you turn corners. the front of the car would not change direction

The 4 "mouse" wheels would be easy enough to turn.

You have a forward roller and sideways roller.  If you run the rear wheels mostly forward and the front wheels forward + sideways, it will turn.
If you run the front wheels right, and the rear wheels left, you would spin in a circle.
Parallel parking would be a cinch.

I'm still not sure of the utility of such a system.  And, you might have troubles designing the balls such that you had adequate road contact for traction and stopping.

Mounting independent front and rear wheels on something like a bicycle fork would give virtually the same mobility, and would be much easier to transfer power and breaking to.

Title: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: Don_1 on 26/07/2011 08:24:13

The problem with tyres is finding the right balance between minimum friction for maximum efficiency when driving in a straight line, friction required to keep the vehicle stable while turning and maximum friction required under braking. Other factors also apply, such as wet, dry, icy and road surface type.

So, who will invent the 'intelligent tyre' which can inflate and deflate itself, in an instant, to give the best grip for all conditions? Anyone fancy a bash at reinventing the wheel?

Title: Why are car wheels and tyres the shape they are? Why not have spherical wheels?
Post by: SeanB on 26/07/2011 20:23:55

That tyre is already with us, at least in purpose built logging vehicles, where the tyre pressure is adjustable on the fly to improve traction on uneven logging tracks whilst still being easy to inflate for low losses at high speed on paved roads.

Also available on the military Hummer, ans on the top Gelandewagons.