Revolt RV-series motor review and comparisons

Super Loctite was sort of joke. They do make many different flavors though. I used some green "wicking grade" stuff that was almost like welding the parts together. I don't remember the number. It was more like super glue.

Yes, any kind of anaerobic locking fluid doesn't work well if there is much clearance to start with. Epoxy might work.

Another option would be some kind of clamping arrangement like a Taper-lock bushing. If the parts are held together tightly enough, the whole shaft would shear off first.
 
larsb said:
I've used the loctite retaining compounds:
https://www.henkel-adhesives.com/us/en/products/industrial-adhesives/retaining-compounds.html
worked well to fit loose shaft to bearing in that application
Click to expand...

Which one? There are many.
 
As already mentiond, it is the Loctite 648 which should be used for that.
The feather key should be up to the task for what the motor is capeable to deliver to the shaft, but i agree that it is a little bit undersized.
btw: it is the torque which will shear off the key and not the power! :wink:
 
madin88 said:
As already mentiond, it is the Loctite 648 which should be used for that.
The feather key should be up to the task for what the motor is capeable to deliver to the shaft, but i agree that it is a little bit undersized.
btw: it is the torque which will shear off the key and not the power! :wink:
Click to expand...

You would be correct for static situations of a powertrain loading, like climbing a smooth flat hill. In practice, the torque the motor delivers is largely irrelevant to the peak loads a powertrain experiences. This is because the inertial loading when the wheel leaves the ground and freely spins up, and then re-contacts the ground again can easily be 50x or more of the peak loads seen by electromagnetic generated torque forces.
 
Shock loads from impacts, even potholes hit by the tamest of riders put so much higher loads on the powertrain than propulsion torque loads, you don't design a powertrain around the torque loads at all, but the shock loads.
 
I've not seen someone put a figure on drivetrain shock load Vs. steady state before so thanks for that :thumb:
 
liveforphysics said:
Shock loads from impacts, even potholes hit by the tamest of riders put so much higher loads on the powertrain than propulsion torque loads, you don't design a powertrain around the torque loads at all, but the shock loads.
Click to expand...
Do you think that size of the drive sprockets or pulleys would have an influence on the shock loads (the feather key sees)?

If we take for example a drive train with 1:5 reduction. one with 10/50T and the other one 20/100T. Same type of chain or belt.

ElectricGod said:
Undersized...lol...can you present a motor that a typical EV builder such as myself would use that isn't undersized in the keyways or union between bell and shaft?
Click to expand...

On my Neu 8057 the shaft is attached to the bell with 6xM5 bolts and inherently glued with loctite:

neu1.jpg

View attachment 1
 
madin88 said:
Do you think that size of the drive sprockets or pulleys would have an influence on the shock loads (the feather key sees)?

If we take for example a drive train with 1:5 reduction. one with 10/50T and the other one 20/100T. Same type of chain or belt.
Click to expand...

I'm sure that has some effect. With smaller sprockets, the chain or belt can absorb more of the shock. It might just mean your chain or belt breaks before the motor shaft.

Speaking of which, on some motorcycles they use a rubber buffer between the sprocket and the hub to reduce the shock loading. Some of these are pretty simple. The sprocket floats on the axle and engages the hub with rubber covered pegs. If you have serious shock load, these things will help a lot.

Rubber-buffer.jpg
 
LFP quote:
Shock loads from impacts, even potholes hit by the tamest of riders put so much higher loads on the powertrain than propulsion torque loads, you don't design a powertrain around the torque loads at all, but the shock loads.
Click to expand...

I never had any issues with keys failing even though i see the point above, for the RV120 motors i am sure the grip fit on axle vs bell did a good job. Before that i used freewheel so no shock loads like described could transfer through to the motor key.

It wouldn't be too hard to do an ok calculation on the forces that can result from the shock loads.
 
Look like you have worked very very hard on these motors EG. You should build your own motor from scratch! Are you going to test the RV100s on an EV to do a practical comparison?
 
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