Removable method of securing motor's axle nuts

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thunderstorm80   1 kW

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Removable method of securing motor's axle nuts

Post by thunderstorm80 » Feb 07 2018 2:49am

Hi,
The lock-nuts on my H3525 come loose all the time because of the very powerful torque it can provide + changing between forward torque&regen + the road vibrations due to the high tire pressure.
I have tried applying a special glue for holding metal-to-metal but it also eventually came loose.
I know I can put some locktite, although I have doubts if it will hold up to the task, but I was aiming to find a removable solution:
Locktite-ed nut can be set free with torque wrench in case I have a flat on the road, but afterward I have to apply it again: Clean the threads, apply, let it dry, etc...
I was thinking of something like a rubber/tefelon strips I can put between the threads and the nut, which can be reused or replaced very easily in case of a flat in the middle of the road.
Has anyone tried something like this?

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amberwolf   100 GW

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Re: Removable method of securing motor's axle nuts

Post by amberwolf » Feb 07 2018 3:29am

Nordlock washers on the nuts

torque arms. (if you already have torque arms then they aren't good enough and you need better ones)

Punx0r   10 GW

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Re: Removable method of securing motor's axle nuts

Post by Punx0r » Feb 07 2018 3:49am

Clamping torque arms
Disable regen unless you really need it

thunderstorm80   1 kW

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Re: Removable method of securing motor's axle nuts

Post by thunderstorm80 » Feb 07 2018 6:20am

amberwolf wrote:
Feb 07 2018 3:29am
Nordlock washers on the nuts

torque arms. (if you already have torque arms then they aren't good enough and you need better ones)
I use Grin's torque arms. One on each side. One is preloaded in the forward torque direction and one in the reverse.
And still - I note that the motor's axle is slowly "digging" through them, by striking back and forth.
Are they meant to be replaced once in a while? I actually remember now that the axle of the H3525 was a bit smaller than the torque arm's matching cavity, and perhaps it's the reason for this slow creeping?
The problem is that not all motors have equal axles: Another motor of mine (TC4080) has a bit thicker axle and that one fits just right to the torque arm, so they have to make it universal, and for most axles there would be that kind of rotational freedom tolerance.
These are the best of the best torque arms. What else can be done?
Maybe using a crescent wrench as a torque arm, and filing it so it SNUGLY fits the axle?
Or another kind of torque arm which you recommend?

Regarding the nordlock washers: I have tried spring-washers and they failed, but I didn't try those.
Considering that my dropouts are made from aluminium, I guess should place such washer between the nut and the torque arm so I don't wear out the fork with each service opening?

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Re: Removable method of securing motor's axle nuts

Post by captain387 » Feb 07 2018 6:47am

You might find a few options in this thread 8)

https://endless-sphere.com/forums/viewt ... =2&t=26444
04 Norco Atomik - Cycle Analyst - Hs3540 - 40amp Infineon Controller - 12s2p 5.8 Ah Turnigy Lipo
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thunderstorm80   1 kW

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Re: Removable method of securing motor's axle nuts

Post by thunderstorm80 » Feb 07 2018 7:27am

captain387 wrote:
Feb 07 2018 6:47am
You might find a few options in this thread 8)

https://endless-sphere.com/forums/viewt ... =2&t=26444
I saw this thread and many more similar ones. I don't have the proper skills/knowledge/good access to laser cutting/metal shaping facilities and to plan such a plate correctly regarding to all the stresses/weaknesses. For example, whenever I create aluminium plates with holes in specific places, I am always wrong by about 1mm, not to mention parallel lines because I can't measure that right (for example the exact location of the eyelets), or I (or the person that cuts for me) doesn't drill/cut it right.
I did liked Dogman's pinching idea with the 2 plates and the 2 bolts, as you don't need to be exact to create it. However, I worry if such pinching plates (even if made from thick steel) can withstand the (rocking back and forth) spreading forces with usage.

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Alan B   100 GW

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Re: Removable method of securing motor's axle nuts

Post by Alan B » Feb 07 2018 8:46am

Nordlock washers will keep the nuts tight if properly used. They must be between the nut and the torque arm. No other washers can be mingled to interfere with the wedge locking operation. Read about how they work. The Nordlock washer pairs are hardened and must bite into the nut and the torque arm. Tighten them daily after wheel removal, after a few days they settle in, stop moving and don't loosen again.

The 12mm axles are too small, a design flaw of that hubmotor, creating excessive forces. Thicker torque arms, clamping dropouts or a custom larger diameter axle such as 14mm with 10mm flats could solve it. Reducing motor current and thereby limiting torque could help also.

Drilling and safety wiring the nut might work also.

John in CR   100 GW

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Re: Removable method of securing motor's axle nuts

Post by John in CR » Feb 10 2018 7:53am

Clamping torque arms for the win, though clamping dropouts are best. I don't even bother with axle nuts anymore except sometimes as decoration. Zero issues in 9 years.

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Re: Removable method of securing motor's axle nuts

Post by 0gri » Feb 12 2018 8:48am

Make your own torque arms from old circular saw blades. Hardened steel will not deform when subjected to torque forces as long as they're accurately filed to fit snuggly.

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Alan B   100 GW

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Re: Removable method of securing motor's axle nuts

Post by Alan B » Feb 12 2018 8:28pm

Using hardened steel will prevent the torque arm from deforming but allow it to slice through the soft axle steel instead.

A torque arm must have enough area to spread out the forces so they won't deform either the axle or the arm.

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Re: Removable method of securing motor's axle nuts

Post by 0gri » Feb 25 2018 9:41am

Yes..... Thick saw blades, or double up.

John in CR   100 GW

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Re: Removable method of securing motor's axle nuts

Post by John in CR » Feb 25 2018 9:55pm

No need for hard steel on torque arms as state above. I've used plain ole mild steel with exactly 0 issues. I use plenty of width. No non-clamping torque arm is much good when you use regen, so unless you make some, then you have to spring for the obscenely priced Nordlock washers.

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Re: Removable method of securing motor's axle nuts

Post by Alan B » Feb 26 2018 6:01pm

I bought a 20 pack of NordLock washers for about 50 cents a pair, and have used them on several ebikes. Some suppliers sell them singly for crazy prices, but they aren't that expensive in modest quantity. They are precisely made and hardened to work properly, and not much else keeps a nut tight when things are moving around while being easy to remove and re-use. Cheap insurance, and the easiest solution. A lot less effort than fabricating clamping torque arms (clamping torque arms are great, but require fabrication effort).

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Re: Removable method of securing motor's axle nuts

Post by John in CR » Feb 26 2018 11:45pm

Good to know they can be had for reasonable prices. I might be inclined to try them on a pedalec power build, but no way no how on my power builds. My approach is to build stuff so it never needs to be fooled with, so while it takes some effort up front it's worth it to me because I'm into convenience, which means no maintenance other than occasionally adding air to the tires. Thank goodness moto tires don't need air as often as bicycle tires. Someday I'll build a solar cell skinned ebike, that I don't even have to charge...just park in the sun. :mrgreen:

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Re: Removable method of securing motor's axle nuts

Post by JanComputerman » Mar 08 2018 5:53pm

Any way you can activate your Regen more gradually would help, but a steel plate that fits on the axle snug and then use screws through it into your aluminum dropout plate in addition to the axle nut should keep your dropout slot from opening up. Go crazy and put plates on the inner and outer sides of the aluminum dropout (four plates) and screw them together.

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Re: Removable method of securing motor's axle nuts

Post by Alan B » Apr 21 2018 12:19am

Here's some real DIY testing of lockwashers (including NordLocks) in Australian. :)

Entertaining and informative. He shows how they don't work if the materials are too hard, and explains in some detail why and how they work.


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Re: Removable method of securing motor's axle nuts

Post by TommyCat » Apr 21 2018 8:58am

+1 on the snug fitting torque arm on both sides.

If you have the room, how 'bout an old school JAM nut? 8)

Image


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T.C.
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