Outrunners supported/held by the shaft?

[zeropointbug]

Alright, here it is. I hope you guys understand the drawing... the red shaft is a custom made shaft to replace one of the diff output shafts. It will travel through the outrunner (replacing the stock unit), and somehow be seperate and free from the outrunner stator AND rotor.

There would be a bearing support for the shaft where it comes out of the motor obviously, and that would be integrated into the whole support. The attaching of the motor should seem simple, but I would need to have both a CD and the motor in front of me to be able to design it, but I would like to get some opinions on whether it can even work. Some sort of adapter plate, but how is yet unknown.

Also, I was thinking Mike's slipperential design could be implemented into it as well, somehow making the attachment onto the slipper coupler on his unit and replacing the gear with a coupler of some sort.

I would just like to hear some comments on whether anyone would even want something like this, or if it's just not worth it plain and simple. I just think it's a cool idea none the less, and would allow allow almost perfect left-right balance in the chassis if twin packs were used and esc was centered, then the steering servo on one side, and the receiver/BEC (or Rx pack) on the other side.

[redshift]

This is just a little guy, but should give you an idea. This one is 38mm diameter X 25 long, 5mm shaft.

[What's_nitro?]

So you're trying to attach the motor to the diff casing, right? Seems like a simple adapter plate would work, or maybe run screws straight through the diff casing into the motor. You'll probably want a bearing around the outside of the diff casing to add support in the area where the two join. Looks like a cool project.

[zeropointbug]

Thanks guys, and thanks redshift for posting that... so are ALL outrunners assemble that way? If so, then that is perfect for the design, of course we just have to be sure...

BTW, I call it the "diff-runner"

[redshift]

Originally Posted by zeropointbug

so are ALL outrunners assemble that way?

That question is better left to the OR experts.

Sikeston..... I see you

[sikeston34m]

This is do-able for sure as long as you consider gear ratios and roll out in your setup.

By connecting the endbell to the diff, you're adding a flex point.

You can get by with this, as long as you use a motor with the endbell bearing. It's a press fit, but will prevent the magnets from contacting the stator during hard acceleration or braking.

Does your motor have the larger press fit endbell bearing?

[sikeston34m]

Originally Posted by redshift

That question is better left to the OR experts.

Sikeston..... I see you

LOL

I was processing.

[sikeston34m]

Take a look at the 3032 Scorpion Motors on the website.

Here's talk about the bearing. Without something like this, you will have problems with flexing.

"The new version 3032 motors now have an extra ring bearing to support the back end of the rotor can for rock-solid stability. This prevents the shaft from flexing under load, and maintains the airgap between the stator and the magnets under all operating conditions."

If the Shaft will flex on longer endbells, your diff cup WILL flex for sure.

[redshift]

Are they all about the same construction Sikes? I know the larger ones use the rotor face instead of the shaft for drive connection, but the guts are the same-ish yes?

[sikeston34m]

Originally Posted by redshift

Are they all about the same construction Sikes? I know the larger ones use the rotor face instead of the shaft for drive connection, but the guts are the same-ish yes?

Yes, most are the same. Also, most outrunners can drive a prop from either end. By either using a collet on the mount side, or by mounting directly to the rotating endbell.

[redshift]

Ok, yeah the outer mounting holes are obviously used in very hi torque apps, and gives you lots of options, outrunners really are the shiz.

And I know the most common use for driving from the stator end is helis, but works great also for like what you did with your outrunner topshaft transmission (really liked that one as well as your DD Revo )

[What's_nitro?]

This is what I meant...

I hope I didn't butcher it too much!

[sikeston34m]

Originally Posted by redshift

Ok, yeah the outer mounting holes are obviously used in very hi torque apps, and gives you lots of options, outrunners really are the shiz.

And I know the most common use for driving from the stator end is helis, but works great also for like what you did with your outrunner topshaft transmission (really liked that one as well as your DD Revo )

Thank you.

I have one of these that I want to do a HV E Revo with, but am waiting on Castle to release a good HV ESC.

8 Pole Heli Motor good for 10S Lipo

http://www.centuryheli.com/products/...&currentid=345

Gear it to the moon.

[redshift]

I'm really liking what I see, but my first thought was that this would be more feasible with a fifth scale. The size to weight ratio would seem to work more in your favor, at least with the motor choices currently available. I had the same idea actually ZP (sorry) but I was thinking about just going live axle, no diff.

Sikes the cogging issue is not what it was one or two years ago, correct? I know the startup algorithms have been improved quite a bit.

And "8 Pole Heli Motor good for 10S Lipo" I gotta say yikes... sikes!

I know you can pull it off...

[zeropointbug]

What's Nitro, I know what you are saying with the support bearing there, but where do you get bearing that size? I have never seen any such bearing.

Sike, I have not bought the motor yet, as I was unsure of which one to get, the HK, or the S model 4035. This flex issue really bothers me as well.



The perfect solution would be a high pole inrunner (12 pole or more), with a large hollow shaft with some sort of outer spline on it to connect to a gearbox (center diff), and one of the output shafts feed through the motor like this. That way, there is no flex issues, you have the cooling of an OUTER stator, the efficiency of an inrunner, and the the motor can be sealed. That is what I would like to see in R/C in the near future... no worrying about gear meshing either.

It's nice to see so much enthusiasm for this.

redshift, I don't understand what you mean by your idea of 'live axle' and no diff. If you mean just an outrunner in the place of a standard motor/diff, then that has been done before. I think the first time when I had the outrunner idea was back in '05 or something, and I was thinking one motor per wheel, no diffs at all, just 2 smaller outrunners placed at each differential location front and rear. THAT would be the ultimate, but we are years away from that kind of thing.