Re: [electricboats] Motor Mount and Thrust Plate design - hoping for feedback

This looks great.  Very tidy.  

You need to add a way to tension the belt.  Make the mounting holes for the motor vertical slots to give maybe 1" (25mm) of overall travel. 

I think your mounting of the thrust bearing forward of the belt is fine.   That's how ZF v-drives are done.    But you may have some issues with shaft diameters to work out.  

I think the trailer hub is a fine solution.  Very robust and affordable in SS.  And it handles thrust and axial loads to keep the shaft aligned.  The reason I didn't use it was simply that I didn't have room.  Its pretty long.  I didn't think of your solution of moving it forward.  That might have worked for me too.   You still need a flange of some sort to mate your unit to the prop shaft.   And you need some way of securing your output shaft to the hub.  I had a threaded section of the shaft basically the same as you see on a trailer axle.  I used a locking threaded ring. 

I adapted a sketch from my setup to better show what I mean.  Left is aft.  I should have flipped it... sorry.

You will need to disconnect the prop shaft at the flanges to change the belt. Not too bad.  You could keep a spare belt already in place and stored back over the stuffing box.  I don't know how much of a concern this is for a nice robust and stiff setup.  I ran for about 300 hours last season and didn't see any signs of issues with the belt. 


Dan Pfeiffer

On 2021-12-28 1:11 pm, Steven Borg wrote:

Next step is to get the pieces together to mount the motor.  I've sketched up several items.  I'm pasting below, but the screenshots are also available here: https://1drv.ms/u/s!Aux_hgfdOOFDsOkKOYmcOH4TvIHSaw?e=Opt1Fo

 

Here's what the final assembly will (sort of) look like, from the side (right is aft). Everything is angled down 8% to accommodate slope of propeller shaft. There are no bolts shown, as that felt like just extra work, and the connection to ways isn't the actual, just something I sketched up quickly. It will actually be more triangular to provide additional support -- what I'm showing here is just to give an idea of how everything connects.

One thing to note is that the thrust plate is fore of the belt, which is different than the Thunderstruck solution. This allows me to switch around the motor mounting direction.



Same look, from the side, facing aft:


Same parts, looking fore:

And here are a few views without the ways and connections to the ways:

 

 

Here are the individual parts (realize that pre-manufactured ones I've just sketched up, so they're missing detail - no threads on bolts, etc.)

 

Motor Mount: (made of 1/2 inch stainless steel)

 

HubSupport / Thrust Plate (also, I've since added one additional hole):

 

 

 

Spacer (3" x 3") to separate thrust plate / hub mount from motor mount plate. Planning to use a hard wood to start with so I can plane it to get the exact depth I need and provide for adjustment:

 

 

Plate to connect Ways Support to Motor Mount Plate (same holes as Spacer and Thrust plate):

 

 

The ways support from the mock-up. Actual will be different, but this shows how the supports are set at 98 degrees to tilt motor plate down appropriately:

 

And that's it. 

Despite the wonderful advice from Dan and Carsten I'm likely going to use a heavy duty trailer hub that's way overpowered for my needs. 

In many ways, this is a first pass at the solution. I expect to learn from this install, and potentially change things up. For instance, given the structure, I could likely replace the trailer hub with a machined part relatively easily.  

Thoughts?

 

:-)
Steve