How do you attach a wheel to a shaft?
 

How do you attach a wheel to a shaft?

Our dimensions for the wheels are: 6" diameter
Shaft is 1/2" diameter.



We need to know very quickly!!!

What's the wheel for? Drivetrain or something else? Do you need it to handle a lot of torque and a lot of speed or no?

Depending on the wheel interior diameter- you would probably want to use a traintorque.

What not to do...
 

Heh - don't hot glue a motor to a shaft and then the shaft directly to the wheel ... a kid at our school (now a team member) found that it didn't work too well for his electronics and robotics class... ;)

- Katie

gluing motors
 

I really hope you are kidding. That would be funny though

Haha!
 

No, unfortunately I'm quite serious! One of our engineers picked up the wheel/shaft/motor and asked, "Who did this?" Then kind of sarcastically said, "Some kid not on the team?" and I said, "Well... no... he joined last week... he's sitting over at that computer..." It was quite funny. I never got to see their machine run, heehee! I wonder if it ever did... :::shrugs::: :)

- Katie

Wheel to Shaft
 

SilverStar,

I am assuming the whell is either for a drive wheel or a ball shooter wheel. In either case, a 1/2" trantorque may do the trick. Go to this website: www.fennerdrives.com

The Torque rating for 1/2" TranTorque is 350 in-lbs (~40 N-m)

The Chiaphua motor with an 18:1 gear ratio is about 40 N-m of output with no safety factor.

Hope this helps.

-Paul

This year our shafts are steel while our wheels are aluminum. To attach we welded a 'yoke' to the shaft then bolted the wheel to it this is the strongest method we have for dissimilar metals. Metal to metal we welded. I like trantorques also they work well as long as you have good tolerances. Also not sure how they work if the wheel was plastic probably not well. If you need more help post the materials of what you are connecting and someone can offer robust advice.

Re: Wheel to Shaft
 

I'll try that...

Doesn't look like that's going to work for us.

The bearings are still in the wheel.

We're going to use clotting pins through the wheels and the rods.

Pins are bad, if there is alot of torque we have had some realllly bad problems with pins breaking in the past. would advise asgainst it.




Andrew

Okay, not using pins.

Still we need more suggestions, trantorque won't work for us...

SHow a sketch...
 

It is hard to recommend a solution when we can't really see the problem.

Do you have a picture or can you scan in a sketch of your set up?

Joe J.

P.S. If you are using Skyway wheels, we have had good success chucking the wheels up on a lathe, boring out the center hold to a whole number (1 1/8 for example), then pressing in shaft and pinning the shaft to the wheel. The larger diameter hole makes pinning an easier thing to deal with.

Another method is to use the Small Parts Inc. adaptors.

Yet another method is to use bolts and spacers. If you have a sprocket that you can get the torque to, then go directly to the wheel spokes with the torque rather than going to the shaft and then from the shaft to the wheel. One way to do this is to put bolts into the sides of the sprocket. Use the spacers to key the bolts perpendicular to the sides of the sprockets. It can work well.

Finally, give us a sketch or a picture to work with and we will have better ideas to share.

Pins aren't always bad if you make sure they have a large enough radius to withhold the maximum applied load. However, if you use pins you should be careful... Depending on the setup, the material around the pin may actually be a lot more susceptible than the pin itself. Lots of time, the material around it will yield (deform to a great enough extent that when the load is released the material does not regain it's original shape). As a result, lots of times the pins will fall out because the pin is no longer a press-fit and is loose. I've seen a number of cases in my years with first where pins fall out during matches or at the worst possible times. I've never seen a pin break although it certainly can happen.

There are also many ways to use pins. You can place them in a number of different geometries, each having certain advantages and disadvantages. I've done a bit of research into pins for a class I'm taking so if you would like I can post all the different types of pins you can use and how to make the associated stress calculations.

- Patrick

Hm, so is there some advantage to locking a wheel and sprocket to a shaft as opposed to locking a sprocket right onto the wheel (a la wheel hub)?

We've always used the SPI hub kits, and just let the wheel ride on it's bearing on a shaft...