Question about lock washer used to secure fan blade coupling from motor shaft? 1

[copperblue]

I apologise if this question is unrelated or not meant for this forum but I have a question regarding fan blades secured onto the motor shaft using lock washer …

For a normal 10" air circulator fans the lock washer or any mechanism used to secure fan blade coupling onto the motor shaft are more simple than the bigger air circulator fans. (As in the bigger one will have threaded shaft with bolt nuts etc but the smaller ones will only have lock washer or something else that's simple).
Some have the self locking starlock washer placed on the half flat sided motor shaft (D shaped shaft) as shown on the picture I've attached and others have other mechanism for securing the fan blade over the motor shaft.

My question is how can the use of a circlip lock washer (e.g. e-clips, c-clips etc) that's placed on the motor shaft (behind the fan blade coupler) secure it from coming/sliding off of the motor shaft? I can't see how a lock washer placed behind the fan blade housing will keep it from coming off the motor shaft? as it doesn't grip onto the fan blade anyway.
Sorry if my question is vague but I'm an novice in things like this so I don't know how to word it professionally. I hope you get the gist of my question.

Thank you!

 

[MikeHalloran]

If the hub of the fan has a D hole molded in ( I can't tell from the photo ), then axial retention is all that's necessary, as the D hole on a D shaft will transmit the torque.

I have not seen the particular fastener in the photo before, but it's clearly a sibling of something normally called a Pal-Nut. They are normally driven into place axially using a wrench socket or something else with a generally tubular shape, large enough to bear on the outer portion of the face without contacting the inward pointing tabs. Pushing on the tabs will usually distort the fastener enough to destroy it. It works, most of the time, by exerting a substantial radial force inward at the tip of each of the tabs.

In this case, they bear on a motor shaft. You will eventually learn that small motor shafts are typically fairly hard and strong between the motor bearings, but the part that sticks out is often/normally annealed dead soft, so the PalNuts will bite into the extended portion of the motor shaft fairly deep, distorting it enough to retain the assembly through the warranty period. ... usually.

Your next question of this type would probably find a wider audience in Mechanical Engineering Other Topics, or in Welding, Bonding and Fastener Engineering.

Please do not post a duplicate question anywhere unless you also Red Flag (Report) your post here and ask that it be removed.


Mike Halloran
Pembroke Pines, FL, USA

 

[copperblue]

Thank you for the reply Mike! Well if you mean the centre bit of the fan blade plastic housing then yes the fan blade sleeving are D shaped. The motor shaft is all hard and is not annealed or anything so the lock washer are one of those that are self locking so the star bit that are flexible adjusts to the motor shaft I believe.
I appreciate your through, professional and helpful answer you have given me. I will take your advice and also post this question on other topics. So I will report my post and ask for it to be removed. Thanks again.