RE: [PSUBS-MAILIST] motor seals (branching off to bearings)

["Wade Carson" <wacarson@interchange.ubc.ca>]

Hey this reminds me!  Does anyone know of a good underwater thrust bearing?
I'm trying to design a counter-rotating prop and I need to know some good
bearings.

Wade

-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Jon Hylands
Sent: Tuesday, August 15, 2000 1:11 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] motor seals


On Tue, 15 Aug 2000 14:48:40 -0700, "Gary R. Boucher" <protek@shreve.net>
wrote:

>      Suppose you had a hemispherical dome where
> inside there are two rare-earth magnets as close to the dome as possible
> and attached to the shaft.  One the outside of the dome there are two
> magnets attached to a stainless shaft in-turn attached to a propeller.
The
> coupling would extend the effective length of the motor by several
> inches.  Perhaps the trolling motor could be mounted inside the same
> enclosure with the hemispherical ends.

The real issue that comes up with this design is: What holds the propellor
shaft in place? You could put a bushing on the end-cap that the prop shaft
would fit into, which would keep the shaft from moving sideways. But then
you also need to hold the prop assembly tight against this. You can't rely
on the strength of the magnets -- imagine what happens when you throw the
thruster into full reverse...

I think we'd basically need some kind of thrust bearing that would work
underwater. Or maybe a couple of teflon washers that rub together -- the
water would probably work okay as a lubricant for that.

Later,
Jon

--------------------------------------------------------------
   Jon Hylands      Jon@huv.com      http://www.huv.com/jon

  Project: Micro Seeker (Micro Autonomous Underwater Vehicle)
           http://www.huv.com