1, the drive shaft bearing damage.

2, drive chain, lack of lubricating oil dry grinding.

3, drive chain to beat bigger cause to take off the chain.

4, motor reducer assembly failure.

Elimination method

1, the replacement of the shaft bearings.

2, to drive chain suitable amount of filling lubricating oil.

3, check the deflection of transmission chain is too large, main, passive sprocket and chain drive is excessive wear, serious wear and tear should be replaced, passive sprocket and chain.

4, replace motor reducer assembly.