Crankshaft Design

Posted by: MolaKule

Crankshaft Design - 03/14/14 11:23 PM

Crankshaft Design
Posted by: Shannow

Re: Crankshaft Design - 03/14/14 11:59 PM

That's a lot of information in a small space, thanks.
Posted by: expat

Re: Crankshaft Design - 03/15/14 12:22 AM

Thanks for posting.

But to put things in perspective:

Austin Seven two bearing crankshaft:

Amazingly they will run 6k rpm
Posted by: edhackett

Re: Crankshaft Design - 03/15/14 12:37 AM

Here's Alfa Romeo's take on a 4 cylinder crank from the mid 50's through the end of production of the Alfa designed engines.

Posted by: Shannow

Re: Crankshaft Design - 03/15/14 01:46 AM

There were some initial problems with bolt-on counterweights, which resulted (as one Formula One designer told me) in "several deep holes being dug in the surface of a few racetracks". There are tensile and fatigue stress issues, as well as the inevitable fretting between contact surfaces and the requirement for highly developed fastener technology.

Having observed more than a couple of high cycle fatigue failures of turbine blades, with horizontal shaft rotating equipment, there is obviously a 2g difference in the centripetal acceleration at 12:00 versus 6:00.

Most of the genuine high cycle fatigue (calc'd at 170x10^6 cycles from crack to failure in most) ones that I've seen have ultimately failed at around 6:00, as evidenced by trajectories and consequential damage.