Electric clutch options

Thread Starter

IanMck

Joined Nov 3, 2019
2
I'm making a boat autopilot for a 17' cabin cruiser.
The first version of this autopilot was only used on the 5hp auxiliary outboard to make sure my electronics and programming skills were up to scratch before unleashed it on the main 75hp outboard.
I need some advice on the mechanical side of things though, mainly a good idea to disengage drive when human control is required instead of the autopilot.
I am trying to keep cost down as much as possible so £100 electromagnetic clutches are out of the question.
The drive motor is connected to a worm drive gearbox and then connected to the steering wheel hub via a timing belt. Obviously with this setup the steering will be constantly locked to the worm drive gearbox and would make human interaction impossible.
What would be the best and most effective way of disengaging drive automatically?
I have explored making a custom electromagnetic clutch using a coil from an AC compressor clutch but this has quite a large footprint and current draw - just over 3 amps and it disipates quite a bit of heat which I would have to sink or cool somehow, I would also have to make the friction disc's and find a suitable iron core for best results so I am starting to think this might not be the best answer.

I am now thinking a kind of flat belt clutch operated with a plunger solenoid or maybe just meshing a couple of gears together with a servo. Or am I missing other simpler more effective options?
 

gramps

Joined Dec 8, 2014
69
How about a drive belt that is a little too big.. Then have a idler wheel on a lever tension the belt when you want to engage the drive. It's a pretty simple and common system.
 

Thread Starter

IanMck

Joined Nov 3, 2019
2
How about a drive belt that is a little too big.. Then have a idler wheel on a lever tension the belt when you want to engage the drive. It's a pretty simple and common system.
Yeah that's one of the ideas I'm leaning against, not sure how much force I would need to apply to achieve direct drive with no slip but that will be trial and error. The lever will have to be electronically controlled with a solenoid or actuator. I'm only driving a force of 20Nm max.
I'm thinking if I go down this route then a V belt would be more efficient than a flat belt?
 
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