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● The backlash and broken bearing of reducer


The Assembly drawing of reducer:

The reducer has ±10 degree backlash at output 4” pulley. There is 4 steps change device (parts no. 23-33) inside reducer.
The backlash is to let parts no. 28 change 4 speeds gear easily. It is easy to think that it’s backlash of gears and the gear was worn out. But, it’s wrong.
If the reducer has noise, the possible reasons: bearings (parts no. 18) are broken. Then, the seal has no support and oil will leak.
If the reducer has noise, operator can open the reducer and replace the bearing (parts no. 18) by NSK roller NU206ET and seal.And then add oil inside.
Video for changing the bearing (parts no. 18):

The reason to cause the bearing (parts no. 18) broken: Operator cuts blind keyway but the bottom of keyway does not have enough space for chips.
So, slotting tool crushes the inside chip then feedback the force to the bearing (parts no. 18) of gear reducer. Operator do the overload cutting.
Then the force feedback to the bearing (parts no. 18) of gear reducer. Example: the material workpiece is too hard (over HRC25).
For workpiece with high hardness, it requires special high-quality cutter or do double cuts to reduce the cutting force. For example, the 18mm keyway can use 10mm cutter to cut it twice.

How to check if the reducer is broken or not?
Run the machine under no cutting. If the reducer has no big noise, then the reducer has no problem.

Replacement of new reducer:
The reducer has also been modified to New Large Capacity Square Reducer (C) since 2017/06.It is not allowed to install in the old machine (manufactured before 2017/06).
For Old machine, the reducer has been upgraded to Strong Bearing Original Size Reducer (B) as well. The bearing at output side of reducer (parts no. 18) has been changed to Super Strong Bearing (there are two strong bearings TWB22206 and TWB22205). The bearing dynamic loading capacity is up to 66.1KN which is 3-4 times compared with original one. The picture of the Super Strong Bearing: