Hi all
High shaft of gearbox broken,any comment to cause.

HS2.jpg (55 KB, 88 downloads) Input shaft

HS3.jpg (8 KB, 85 downloads)

I cannot see the second attachment. Can you please post it again. A close up of the fractured section would help.

I could not see 2nd attachment either.

As Elias said, a closeup in-focus picture of the fracture is needed.

Are we looking at the output shaft outside the gearbox and the discolored area is where the coupling hub sat? If not: is the fracture between bearing and gear or is it between bearing and coupling (looks like between bearing and coupling). How far from the fracture to the coupling? And to the keyway? And where is nearest step in shaft?

And did anything abnormal show up on the vib prior to failure?

And do you happen to know the shaft material?

A complete description of complete machine train certainly wouldn't hurt

Pete,
thank you for your comment.

quote:

(looks like between bearing and coupling)

yes,you are right.

quote:

How far from the fracture to the coupling?

maybe 15-20cm

quote:

And did anything abnormal show up on the vib prior to failure?

vib spectrum shows 0.5,2X,1xGMF,2xGMF, but the level just 2mm/s.the vib trend has not changed obviously。

quote:

And do you happen to know the shaft material?

i do not know .

HS3.jpg (8 KB, 60 downloads)

sorry add again

HS3.jpg (59 KB, 67 downloads)

Leisure,

Are there ( such as in the the keyway, coupling ) any physical signs of torcional vibration?

Can you measure motor current in order to detect variable torque.

Also shaft misalignment will also contribute to shaft bending fatique in particular if coupling is locked.

David,

quote:

such as in the the keyway, coupling

i do not think so

quote:

Can you measure motor current in order to detect variable torque.

no ,only measure vib

quote:

Also shaft misalignment will also contribute to shaft bending fatique in particular if coupling is locked.

usually there is a flexible coupling to reduce misalignment.however,in"HS3"picture,i cannot see the elastomeric flexible coupling only the coulping locked on the input shaft of gearbox. may be the elastomeric flexible couping lock on the motor output shaft. in this case,i have to check the gearbox input shaft diameter,does it larger than motor shaft.if the motor shaft is larger.i should incrise the gearbox shaft diameter or intall a elastomeric flexible coupling locked on the input shaft of gearbox. Am i right