using a geared hubmotor under water?

Boats, Jet Skis, Kayaks etc., including hovercrafts
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ccgarnaal   1 mW

1 mW
Posts: 14
Joined: Mar 10 2018 1:46pm

using a geared hubmotor under water?

Post by ccgarnaal » Sep 15 2018 6:47am

I would like to build a handheld rotating brush to clean the hull of my boat.
Something like this: http://www.maxdepaz.es/clonar/wp-conten ... 902220.jpg
On a much smaller scale.

I could drive it with a belt from above the water. But having a geared hubmotor in the brush would be awesome.
I have a large lathe and can machine my own parts.

So first question:
How is the stator connected to the shaft on a bafang geared hubmotor?
Has anyone every replaced the shaft of a motor?

My idea is to machine a new stainless shaft longer then original with a large smooth area outside the hub. Bolt new machined aluminium housings to the outside the side of the hub and house double lipseals in these parts that seal on the shaft. The same way a regular outboard motor gearcase shaft seal is made.
Most dificult part might be getting the wires trough the new shaft.

And maybe fill the motor with outboard gearcase oil? With a inspection plug to check for water.
So in case of water leakage the oil start turning too milk and nothing is damaged yet als long as the oil is replaced on time.

All ideas welcome.

ccgarnaal   1 mW

1 mW
Posts: 14
Joined: Mar 10 2018 1:46pm

Re: using a geared hubmotor under water?

Post by ccgarnaal » Sep 15 2018 6:56am

Aditonal idea,
If anyone knows a slow rpm geared hubmotor with the cables coming out the end of the axle.
Then I could just machine sleeves that screw over the threaded ends of the original shaft leaving the original shaft intact.
Less work for the same result.

Voltron   1 MW

1 MW
Posts: 1857
Joined: May 02 2013 4:53pm
Location: Santa Barbara CA

Re: using a geared hubmotor under water?

Post by Voltron » Sep 16 2018 11:04am

It's a different track, but maybe an air powered tool to avoid the water electricity combo.
But if you stick with electric, most rc type out runner motors will work under water without sealing.
A geared motor technically has a rotor spinning on the axle inside the case. With direct drive the stator stays put while the motor case spins around it.

ccgarnaal   1 mW

1 mW
Posts: 14
Joined: Mar 10 2018 1:46pm

Re: using a geared hubmotor under water?

Post by ccgarnaal » Sep 16 2018 2:11pm

I've used air powered tools under water before.
But this would need more torque at a slow speed and more portability.
An airpowered motor of 500W would take a serious compressor I don't want to haul around.

Ik konw the center is stationary, that is the whole idea. Ideally the motor would be inside the brush tube and thsu completey inside. With only the shaft and the bracket holding the shaft being stationary.

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