Shaft Failure in Translation Gear Reducer of Bucket Wheel – Need Help Identifying Cause

[fairyfales]

I’m working on an engineering project analyzing the cause of repeated shaft failure in a translation gear reducer that drives a support wheel of a 400-ton bucket wheel excavator.

System Details​

• Shaft material: 42CrMo4
• Motor power: 5.5 kW , n=1000 t/min
• Reducer output power: 4 kW
• Gear ratio: 150:1
• Number of support wheels: 16
• Each shaft supports 1 wheel (load ≈ 25 tons)
• Bearings: 2 cylindrical roller bearings
• Support wheel diameter: 710 mm
• Translation speed: Varies between 1.5 mm/min and 15 mm/min

im a bit lost on the calculus , can someone assist me with approaches i should follow and calculus i have to made ? ( it usually breaks from the spline section)

 

[waross]

Are the support wheels friction drive on the bucket chain or are is it a sprocket or some other type of direct drive?

 

[GregLocock]

MJ - I don't know why i said shear, anyway dvd's link identifies it pretty clearly.

 

[waross]

Out of the 8 assemblies, does the shaft always break at the same assembly location?
That is, perhaps always the first in line?