Distance between tapered pins 1

[MGZmechanical]

Hello. I'm designing a shaft - hub joint with tapered pins. The problem is that the hub is quite short and I have to use two pins due to the high torque. Is there any reccomendation about the minimum distance between pins?

Thanks

 

[racookpe1978]

What diameter shaft?
What diameter of the pins?
What diameter of the (pulley) load flange?
What amount of load on the shaft-pulley?
How are you going to "fix" the tapered pins from being vibrated out of their holes?

 

[MGZmechanical]

Hi, is a 200 mm shaft with 2 x 50 mm diameter pins. The torque is 70000 N·m applied with a quarter turn electric actuator.

We use to tag weld all parts under vibration.

I don't know if there's some exact way to calculate the distance between pins. If not I would appreciate some general reccomendations (like the pin diameter should be from 0,2 to 0,3 the shaft diameter or distance between bolts 2,5 times the bolt diameter). Is there something like this for tapered pins?

Thanks in advance.

 

[GregLocock]

Why are the pins tapered? The taper will help the pins to writhe out of the holes.

What is the advantage of this horrible setup over a taperlock or something you'd find in a catalog?

Can you sketch it?

Anyway it is a nice little FEA problem.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[MGZmechanical]

Hi see sketch attached

 

[GregLocock]

Well I can see where the historical background is, that's roughly how Ogg jammed the first wheel onto the first axle.

Can you put the pins at 90 degrees?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Cockroach]

Rotate one of the Dowel Pins 90 degrees to remove it from the shear plane of the second. This means you will need to have two holes orthogonal to eachother, Hub & Shaft.

Depending on your exact Dowel Pin, Shaft OD and Hub ID, the distance between centres will be governed by your maximum peek torque input load. The shaft can be analysed as a stress concentration between holes, classical equations are in Roark's. I would prefer to do a FEA model on that, then check the output based on the classical model. You should be within 3% error.

Hope this helps.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[Tmoose]

Does the load reverse?

 

[Cockroach]

Here you go. This is what I would do. 156.25 mm between centres and rotate holes to orthogonal plane.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[MintJulep]

Unless it is the design intent to plastically deform something when installing the pins the load will not be distributed between the pins.

The second pin driven will in all likelihood take all the load.

So you might as well just design a single pin connection.

 

[Walterke]

what material are you using for the pin? Whats it's maximum allowed shear pressure?

NX 7.5
Teamcenter 8

 

[SnTMan]

Cockroach, you really are amazing.

Regards,

Mike

 

[MGZmechanical]

Hi, I would try with a FEM model and the indications from Cockroach (I was amazed) and aslo will check what MintJulep said. If I come to some conclusion I'll let you know. But will have to wait, now I have 4 days off. Feliz vispera de todos los santos (happy halloween for english people).

 

[Cockroach]

WalterKe, on the computation sheet, top, I indicated material as AISI 4140/4130 HRc 18-22. This is equivalent to L80 alloy steel.

Thanks for you kind words SnTMan & ManoloGalarraga. I believe this is the whole purpose of the forum, to make it a learning experience and capture from others on a particular problem.

Good luck with the design.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada