Force diagrams for an automotive rim
Force diagrams for an automotive rim
(OP)
I am trying to design a custom automotive rim, but I am not a mechanical engineer and I would like some help in finding an existing drawing or diagram outlining the forces acting on a rim and how to balance them out with thickness and structure. I understand moments about the axes and simple physics, but an existing drawing would be much easier than starting from scratch. I'm not looking to infringe on any patents, just somewhere to start.
thanx
rich
thanx
rich
RE: Force diagrams for an automotive rim
As to the forces. Things you need to consider are one off events like potholes and kerbs, and then the rotating fatigue events.
Are you designing a steel wheel or an aluminium one? each has particular problems. fatigue of the flange is surprisingly common, as it flexes with each rotation. design of the spider for steel wheels is also a big fatigue issue. Alloy wheels tend to have more trouble with the impacts.
Cheers
Greg Locock
RE: Force diagrams for an automotive rim
I have another question, if I wanted to design a remote PSI sensor,to be installed in the rim, what is the best way to machine a hole or threads in a rim without worrying about it leaking? I know that it is a lot, but I am ambitious!
thanx
rich
RE: Force diagrams for an automotive rim
In an alloy wheel the structure of the webs around the bolt holes is crucial to maintaining the stiffness and strength across the spider. Therefore you will find it difficult to design a spider that can accomodate much variation in the bolt pattern.
If you want a leak proof seal in the rim just use a valve body - the T&RA book specifies the dimensions, and the mating part is easy to obtain. Unscrew the valve's guts from inside the body and you have a perfect leaktight pressure port. T&RA gives the thread size, which is some weird combination of inches and millimetres.
I think you will also find that there is very little in common between a 15 inch wheel and a 17 inch wheel. As a guide the spider for a 14 inch steel wheel is made from 3 or 4 mm steel. That for a 16 inch wheel for the same car is made of 6 mm plate.
Cheers
Greg Locock
RE: Force diagrams for an automotive rim
RE: Force diagrams for an automotive rim
http://www.us-tra.org/main.html
The handbook can be bought on CD-ROM and will set you back $65.50 .
RE: Force diagrams for an automotive rim
RE: Force diagrams for an automotive rim
Aftermarket wheels seem to be designed by copying other wheels, or developing fresh shapes (it must happen somewhere!) in-house. The obvious approach there is to send your designs in to a wheel manufacturer.
Cheers
Greg Locock
RE: Force diagrams for an automotive rim
Let me know if you want more information.