Adding metal bearings to the Roomba 500/Roomba 570 Gear Box
Before buying my Roomba 570, I was aware that the Roomba 500 series had a design flaw that causes the gear box to fill with dust and hear which would eventually cause it to malfunction. This video on YouTube by another Roomba owner details the problem.
I was hoping that iRobot would have already resolved the issue by the time I got my Roomba. After running my Roomba for a week, I opened the gear box casing to find it full of fluff and cat hair. The dust and hair enters through rather large gaps between the roller/brush driver cogs and the hole in the gear box casing they protude out of.
I found this post by vic7767 from RoombaReview. vic7767 uses ball bearings to allow the driver cogs to protude from the gear box casing whilst keeping the gear box casing sealed (no gaps around the edges).
The sizings of the ball bearings are pretty standard and I found a local supplier of bearings that had all three sizes necessary in stock. The sizes (Dxdxw) are 23x17x4mm, 10x15x4mm and 6x10x3mm.
Here's some pictures of my mods:
Medium sized driver cog with the bearing mounted. The cog had to be filed down a bit to fit the bearing.
The large driver. This had to be filed down several millimetres too.
The large driver cog and the bearing next to it.
The smaller driver cog in place. The hole in the cog assembly had to be widened with a file.
The opening on the left is what things are like without bearings. Even with the driver cog inserted, the opening left plenty of room for dust and hair to get pulled in.
Both driver cogs with bearings fitted.
The cogs fitted in the cog assembly with the bearings. No more gaps for dust to get in. Nice.
The smallest driver cog (mates with the motor shaft) along with its matching bearing.
The smaller cog fitted onto the cog assembly. Slow and careful filing gave the cog a nice tight fit.
The cog assembly from the inside with all cogs fitted.
The fitted cogs and bearings again.
Roomba on his back with the back cover off.
The driver cogs with the brush and beater fitted.