Re: [CAD_CAM_EDM_DRO] Re: best type of hub for pulleyts (DONT USE A KEY)

I recently worked on a CNC router with keyed pulleys. As it was servo
drive the control compensated for backlash in the keyway until it got
really bad. When we took it out the key was round, rather than square
and the keyways were totally mashed. In the end we got the servo shaft
ground down and fitted a taperlock pulley.

Les

c_holm10017 wrote:

>
>Something interesting I recently learned from motorized wheelchair
>users regarding the use of keyways to fix a wheel (pulley) to a shaft
>is : DON'T
>
>Keyways are excellent for use where there is no reversing cyclic
>load. In that instance, the load is always on one face of the key.
>
>For a reversing cyclic load, guess what happens. If the pulley isn't
>tight enough on the shaft without the key so as to keep the load from
>changing from one key face to the other, in short order you have a
>lot of wear, a very sloppy connection, and noise.
>
>It turns out this design flaw is incorporated into almost every
>motorized wheel chair and causes no end of complaints when the wheels
>get a little loose and the key starts to wear. CLUNK CLUNK with every
>direction change
>
>In a CNC machine where backlash is undesired, the slop is equally
>unwanted.
>
>Recommendation from the mobility impaired? A friction clamping
>pulley no key.
>
>Chris
>
>
>