Clamping Force of shaft collar 1

[josevski]

Hi All,

If I have a collar(cut into 3 pieces, each cut is threaded on one end and a hole on other end to hold the bolt) that I have to clamp to a shaft using 3X 14mm zinc plated high tensile bolts (14.9 grade). If I tightened the 3 bolts, what will
be the clamping force of the collar to the shaft(assuming preload of each bolt is 86 kN)? Thanks and Regards.

 

[electricpete]

I gateher the collar is three partial-arc pieces of 120 degrees each, bolted togather?

As first guess, when bolted together these act like a ring. If you assemble ring without the shaft, will what would the inner diameter be and how much smaller than the shaft?

Perhaps post a sketch with dimensions and materials so people can get an idea what will deform as you tighten.



=====================================
(2B)+(2B)' ?

 

[dvd]

One can't make the part perfectly and shafting is not perfectly round, nor perfectly sized. You aren't going to be able to calculate a very good answer. I recommend testing.

Why three-piece?

 

[MintJulep]

For perfect fit case Mr. Newton says 3 * 86kN.

 

[Tmoose]

How much do you need, and what happens if it slips?

When there is significant axial thrust (single inlet fan or pump) and thrust collars are used with journal bearing pillow blocks a groove is sometimes (often?) machined in the shaft so friction is not the main source of restraint.

http://www05.abb.com/global/scot/sc...d9a85257b4400559d7d/$file/MN3065_3065-310.pdf

 

[MikeHalloran]

Experience says that three independently made collar sections will not grip as well as a collar manufactured in one piece and then sawn apart.
... and that three piece cut assembly will not grip as well as a collar manufactured in one piece and then sawn in only one place.

There will be some dependence on the sizes of the parts and the shaft, and the materials, so far unrevealed.

I recommend just buying the damn thing; making your own shaft collars is lunacy, unless you can make a serious reduction in part count by combining the shaft collar with some other part.



Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

Josevski's other 2 posts (on the sealing board, with zero replies ) are about ~ the same thing.

 

[josevski]

Thank you all for your posts. This is for a mechanical seal to be fitted vertically without using grub screw that damaging the sleeve. We used shrink disc before but very time consuming to fit. 54bar pressure is the sealing pressure. We have approximately 45 kN of axial force we are trying to counter. I am looking for this 3 piece collar to clamp the sleeve to the shaft(machined then cut into 3).Is 3XM14 good enough to use? considering both bolts and clamp collar made from high tensile steel(10.9) zinc plated.