Creating a Hub for a D-shaft
Creating a Hub for a D-shaft
(OP)
Hi all,
At first it seemed like an easy thing to do, but not so sure now
.
I need to assemble a Hub on a D-shaft of 15mm Dia., the Hub already has a hole of 10mm Dia. so it needs to be enlarged and create the "shelf".
.
Can this be done without creating large radius (anything over R1 mm) at the seem between the hole and the "shelf"?
At first it seemed like an easy thing to do, but not so sure now
.I need to assemble a Hub on a D-shaft of 15mm Dia., the Hub already has a hole of 10mm Dia. so it needs to be enlarged and create the "shelf".
.Can this be done without creating large radius (anything over R1 mm) at the seem between the hole and the "shelf"?





RE: Creating a Hub for a D-shaft
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Creating a Hub for a D-shaft
Aidan McAllister
Metallurgical Engineer
RE: Creating a Hub for a D-shaft
RE: Creating a Hub for a D-shaft
RE: Creating a Hub for a D-shaft
Are the torque requirement so great a set screw and a sprocket with a 15 mm D bore would not work?
Or, must the sprocket slide?
At some point I'd consider afixing a plate or bar to the side of the sprocket to D-ify the bore.
5 down 5 to go.
RE: Creating a Hub for a D-shaft
by "shelf" i meant the flat feature in the bore.
The torque is the issue.
If the hub is 23mm thick, what is the most cost effective method from what you've suggested?
The wire EDM sounds like the best option for its accuracy but looks expensive.
RE: Creating a Hub for a D-shaft
What equipment is at your disposal?
What material is the hub made of? Steel? How hard?
A file has been mentioned, as have some very sophisticated techniques. They are vastly different, but each could actually be the perfect tool, depending on the circumstances.
Deify the bore! All hail Bore!
RE: Creating a Hub for a D-shaft
Does it need to be "done right" or do you just need it to work?
RE: Creating a Hub for a D-shaft
I'm outsourcing the job.
The hub is Hardened steel (waiting for a reply from the hub supplier for a more accurate description).
I need it done right, with very specific and tight tolerances.
RE: Creating a Hub for a D-shaft
RE: Creating a Hub for a D-shaft
RE: Creating a Hub for a D-shaft
When it comes to couplings we are always here to help.
WWW.PSCCOUPLINGS.COM
RE: Creating a Hub for a D-shaft
Draw what you need and allow your suppliers to quote. You don't care how the hole gets made, just what the final shape is.
RE: Creating a Hub for a D-shaft
If it'll be to pricey to make i'll have to come up with a different solusion, which will effect other components in the system where the hub will be installed.
RE: Creating a Hub for a D-shaft
It is going to be expensive, mainly because that feature is usually cast into the hub and it isn't a precise fit. But in order to cut it you have to either have space to get a tool in (which you don't) or EDM it.
When it comes to couplings we are always here to help.
WWW.PSCCOUPLINGS.COM
RE: Creating a Hub for a D-shaft
Im not very familiar with wire EDM, only from the media and a few parts tha I played with which some of the had a closed feature cut out from the middle without any apparent guide slots or holes. At list I didn't notice any.
RE: Creating a Hub for a D-shaft
Kyle
RE: Creating a Hub for a D-shaft
I understand that you care about cost- but the quickest way to determine how much a parts costs is not to ask questions of forums about design details... the quickest method is to create a drawing detailing what you need, and send that drawing to suppliers for quoting.
RE: Creating a Hub for a D-shaft
When it comes to couplings we are always here to help.
WWW.PSCCOUPLINGS.COM
RE: Creating a Hub for a D-shaft
How much torque are you transmitting thru a compromised 15 mm shaft?
Is an outboard bearing planned? The chain tension as a result the torque is trying hard to bend a cantilevered shaft, and if the D shaft in on a purchased part like a motor, the loading on the adjacent bearing may exceed what the motor manufacturer had in mind.
Any hub connection that is not clamped hard enough to resist micromotions due to torque variation and one direction radial loads is destined to experience progressive fretting wear, like the outside of this bearing race -
http://www.skf.com/binary/31-5621/ls401_48_tcm_12-...
or this keyed shaft connection-
http://photos.motoiq.com/photos/685053521_4wehK-M....
RE: Creating a Hub for a D-shaft
it is common to broach large quantity's with a "D" hole. and it is precision hole.
bear in mind core hardness can not be more than 43 HRc. approximately.
if core hardness is 50 HRc or higher the options to broached before heat treat with a core harness of 33-43 HRc.
then do a final heat treat.
but must importantly it has to be a very stable material with very little distortion.
wire cut is an option but only for small production lots because of cost. plus there is always the issue with recast
on the surface. but if the means override the cost it is a very practical method.
a key way or splined hole would require the same procedures, but it is common.
if the material (for an example) is 4340M or 300M is has very little distortion when it is vacuum heat treated and gas quench ( high bar )
the problem is the precision required at assembly. and if alignment is required. then the cost is justified.
might also consider a press fit between details. easy to grind the O.D. easy to hone or ID grind the bore in the hub.
Best
RE: Creating a Hub for a D-shaft
Send you requirement to whoever you are buying the sprocket from and ask "How much?"
RE: Creating a Hub for a D-shaft
RE: Creating a Hub for a D-shaft
http://ringfeder.com/en/international/products/rin...
RE: Creating a Hub for a D-shaft
As usual, plenty of useful info.