This shit be super fucking loud...But Why?

So, this shit be super fucking loud, but why is the question.... and how can we fix it is another question. One more question is how to make it faster... 

Let me bitch a for a sec...  This a problem we’ve had from the start. Why you may ask, because this shit is complicated moves really fast.  I also haven’t spent enough time learning about this system and understanding all the factors that affect it's performance. Knowing that may take a lifetime... well I've got a day. Happy Wednesday! 

"Make it faster"

"Maker if quieter"

"Make it great again"

I first looked into every possible contact point in the system to see why where we can reduce unnecessary friction and unwanted movement that causes noise 

 

Bench marking 

 

All the contact SURFACES

Luckily there are only a few points of possible complications here: JK there are a fuck ton, but we can knock a lot off the list 

skitch.jpg

Probably doesn't reduce speed

Probably doesn't cause noise

  • Low likelihood of friction
    • Bristle Plate Bushing and Rot. Pin
    • Bristle Plate and Rot Pin Boss
    • T-bar and body
    • T-bar and tip of bristle plate bushing (not called out)
    • T-bar (short end ) <> Bristle plate inner bushing
    • T-bar <> Wings
    • T-bar (long) and Bushing cut out
    • Bristle Plate Trough ends and Lock Pin
    • T-shaft inner body wall
    •  
  • Relative velocity between contacting parts are low
    • Bristle Plate Bushing and Rot. Pin
    • Bristle Plate and Body Top surface
    • Bristle Plate and Rot Pin Boss
    • Lock Pin and trough Top/Bottom
  • The offset distance between parts is large, so they probably art contacting
    • T-bar and body
    • T-bar and tip of bristle plate bushing (not called out)
  • Fitting is just right 
    • T-bar (short end ) <> Bristle plate inner bushing

PROBABLY CAUSEs NOISE

PROBABLY REDUCEs SPEED

  • Relative velocity is very high and offset is too small (bad combo)
    • Bristle Plate Trough ends <> Lock Pin
    • T-bar (long) <> Bushing cut out
    • T-bar <> Wings
    • T-shaft <> Metal T-shaft Handle
    • Coupler <> Handle
  • Lots of friction
    • Bristle Plate <> Body Top surface
    • Lock Pin <> trough Top/Bottom
    • T-shaft <> pin bushing boss
    • T-shaft <> Coupler
 

Bristle Plate Trough ends <> Lock Pin

The handle rotation is designed at ∓28° the head is designed a worst case scenario of 40°... and yes it's a worst case right now. See that extra room between the metal pin and the end of the trough? Well that's not helping.   

Bristle Plate <> Body Top surface + Lock Pin <> trough Top

These two surfaces have a large contact area and are put under more pressure by users. Adding a little lubricant or water durring use does increase the speed. Fun fact, durring dry use the head speed can drop (4300->3800rpm) because the friction heats up the plastics, causing expansion and more friction.  

 

T-bar <> Wings/Bushing Cutout

T-bar can hit the side of bushing gap as it's shown in the pic, but the weld design actually greatly reduces the likely hood of this being a problem. On the other hand the T-bar is coming very close the Wings. Because our head is actually smaller than Oral-B's we don't have a ton of room to play with, so I don't think there is an easy fix here. 

Trans shaft being squeezed by the housing and coupler

This is a balancing act to keep the trans shaft movement fluid, without effecting its ability to snap onto the handle. 

Rotation

The goby brush oscillates 25% more than the OB-3000, and is only 80% lounder... I should be in marketing

Even though the system has a buffer to ensure it doesn't impact, shits still making impact all over the place. Fuck this shit...

 

After looking at the Oral-B product they actually have the same problem :) but unlike us they built a plastic<>plastic surface to stop the movement. We are currently using the lock pin to do this, but it's fucking loud(as you know) 

What if we add a LSR contact surface or a pom diving board... it only has to last 2,000,000 cycles.... fuck ballz

Well it can't be overmolded... assembled? 

Wait maybe in can?!

 

Stopping over rotation

OralB uesing a hard stop