On Sep 28, 4:29*pm, _
wrote:
On Sat, 27 Sep 2008 21:52:43 -0700, Bob in Phx wrote:
Ok, I need some suggestions here. I have an electric bike motor that has
"spun" a gear. The shaft is mild steel and the gear is hardened. the gear is
about 3/4 of an inch across and the shaft is about 3/8's or so. The gear and
shaft are press fit. The max torque that this gear and shaft see is around
35 foot pounds. When the motor gets hot, the gear slips, but I can not pry
the gear off. The gear is attached to the rotor of the motor with the
comutator on the other side of the housing. A couple of folks have had this
same issue. They have been able to remove the gear by hand and then use
bearing retainer and JB weld to mate the shaft and gear again. The motor
never gets above 150 degrees.

my options as I see them.

Keep using the motor until the gear is so loose that I can pry it off and
then "glue" it back on. I don't want to do this, as I am scared that the
shaft damage and may not be symmetrical, thus the glued on gear could be out
of wack.

I could try and just jb weld the top of the gear to the shaft. The shaft
sits down inside the gear by a couple of 10ths. The problem here is that I
don't know the amount of torque that jb weld can stand in this
configuration,

I could have a pin machined through the gear and shaft, but I am worried
that the hole in the gear face could cause a wear on the driven gear.

There is no (well, extremely little) radial force on the root or crest of
teeth. *Place the pinhole from rott-to-root or crest-to-crest (or root-to
crest if odd teeth); insert & loctite pin, file away any burr, done.

"_" is a paedophile by his own admission:

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