The very latest news and updates for the iRobot Roomba robotic vacuum, the Scooba Robotic Washer and the Dirt Dog workshop sweeper. All discussion and troubleshooting questions go here.
May 13th, 2013, 8:47 pm
Got the big bearing to fit instead. Now my roomba has bearings on both ends of the brushes... Just because I love bearings so much (had a few extras from my chm mod)
May 13th, 2013, 8:53 pm
I can't remember the dimensions but I think there is a sealed bearing that I used in the earlier 4XXX bronze bushing end caps. Problem is that the bearings cost more than new end caps.
I just concentrate on the brush gear assembly and leave the other ends alone.
February 28th, 2014, 5:19 pm
Very nicely explained Vic!!
This is genius !
Keep up the good work
January 28th, 2015, 1:16 am
are the bearings used on the Grey CMH the same size as the ones for the Green CMH?
1) 6 x 10 x 3 mm bearing for the brush motor from VXB.com,
2) 10 x 15 x 4 mm bearing for the small rubber brush.
3) 15 x 21 x 4 mm
January 28th, 2015, 1:38 am
The small 6x10x3 is not needed. The other two are the same size.
January 28th, 2015, 1:54 am
SO the grey chm only takes 2 bearing, I could have sworn I saw 3 in a picture you posted of a grey one in another thread.
vic7767 wrote:The small 6x10x3 is not needed. The other two are the same size.
January 28th, 2015, 10:59 am
It's possible but I no longer install a bearing into the brush motor gear. It's not necessary.
June 12th, 2015, 7:30 am
I finish the green CHM mod for my roomba 555 yesterday.
Thanks for useful guide and photos.
June 12th, 2015, 9:34 am
Very happy that this thread contributed to your success.
June 16th, 2015, 4:37 pm
I forgot to post some horrible pictures before the mod of my roomba 555. I suspect previous owner never clean it properly that's why the battery couldn't hold a charge. Now it's running for 1 hour on hard floor only (battery have dates 2010-2011 - I don't know if this is the actual manufacture date.)
Thanks again vic.
January 31st, 2019, 4:27 pm
The sound of my roomba has always annoyed me so I designed a 3D printable involute herringbone gear set for your mod. Helical gears are quieter and the herringbone profile further balances axial shaft forces.
STL files for printinghttps://www.thingiverse.com/thing:3391183
The final motor current for transmission gear set was 220 ma. Initially it was closer to 500 ma and just as noisy as the original spur gear set but they very quickly improved. While the initial printed gear surface looked excellent, they must have had microscopic surface blemishes and inaccuracies. By greasing the axles and running in the gears with no tooth lubrication I assume some bits were knocked off, pushed out of the way, and the surfaces polished into a precision gear set. After 10 minutes the set was running smooth, however I ran them for 1 hour from a bench power supply before lubricating the teeth and putting the transmission cover on.
The quest for further roomba noise reduction then focused on a rather quick Neanderthal mod to the beater bar. Grab the ends and twist as best one can into a spiral. Any twist is an improvement and the resulting spiral is not something to write home about. The twist reduces the CHM bouncing as every blade hits the floor.
January 31st, 2019, 6:48 pm
Peter101 wrote:I designed a 3D printable involute herringbone gear set for your mod.
Peter thanks for the info and 3D files for the R2 CHM Brush Deck. I may print these out in the near future. Don't know if I'll use my old Create 3D printer or look for an upgrade printer.
February 1st, 2019, 3:16 pm
Vic I appreciate you sharing your mod
a youtube channel called makers muse is all about 3d printing and is worth searching for 3d printer reviews etc. https://www.youtube.com/channel/UCxQbYG ... 2ND-AfIybg
I got a relatively inexpensive cetus3d mk2 extended one year ago and everyone is impressed with the surface quality of things I have printed. The build volume is smallish 7x7x11 inches so you have to think about the accuracy vs size tradeoff (insert manhood joke here). For me printing threads is my must have and now I have added gears to my list.
I designed a thread printing calibrator, a little like a micrometer, to measure thread clearances and tweak the PLA temperature, print cooling, and anything else you can think of that might affect print quality. Honestly, you have to be able to print great threads before you can print good gears.https://www.thingiverse.com/thing:3390910
February 5th, 2019, 1:23 pm
Photo removed, gear identification error.
Last edited by vic7767
on February 6th, 2019, 10:15 am, edited 1 time in total.
February 5th, 2019, 5:18 pm
Vic I updated my thingiverse post and added some pictures of the printed and installed gears etc.
This picture is my old CHM (herringbone gears inside) with the twist beater mod that helps reduce the thumping noise. The twist helps reduce CHM bouncing as a portion of the rubber blades is always touching the floor.
February 5th, 2019, 6:23 pm
Gotcha, I just need to print one more (L) or (R) gear and possibly have to flip it to mesh with the other gear.
February 6th, 2019, 3:08 pm
For scale and focus the squares on the graph paper are 5 mm / 0.2 inch
These gears are straight off the printer and have not been run in yet
The gear on the right, one square from the meshing shows some slight layer misalignment
these take 10 minutes or longer of running in the transmission with no grease on the teeth to polish and correct