Spur gear wear
Spur gear wear
(OP)
I have a pinnion of 21 teeth, 3 dia. pitch, 20 degree pressure angle, RC 28-32, 3" face width, climbing a rack which is RC 48-52 4130 alloy steel. The stroke on the lift is 40" 2x every 5 minutes is the travel at 10"/sec.
The four pinions carry approx. 9,000# each in the front and 6,000# each in the rear. There is a soft start with little shock loading.
The proplem is the pinnions and rack pitch lines were set tight with no backlash and resulted in considerable wear. The question is if I set the pitch lines correctly and increase the pinnion gear hardness to match the rack, will the gears live or are the pinnions now too brittle? I need to get to 10,000 hours of operation.
The four pinions carry approx. 9,000# each in the front and 6,000# each in the rear. There is a soft start with little shock loading.
The proplem is the pinnions and rack pitch lines were set tight with no backlash and resulted in considerable wear. The question is if I set the pitch lines correctly and increase the pinnion gear hardness to match the rack, will the gears live or are the pinnions now too brittle? I need to get to 10,000 hours of operation.





RE: Spur gear wear
with a greater Rc hardness. The loads
do not look that heavy. What kind of
grease are you using and how many hours
are you getting now? How is the pinion
hardened? Carburized or Induction Hardened?
What is the core hardness of the pinion?
I would assume the back pinions saw very
little wear with respect to the front pinons.
RE: Spur gear wear
RE: Spur gear wear
a load? If not you might want to
consider a 50 percent long addendum
system. The pinion will be greatly
stronger and the wear should be much
less. I would use an ep2 grease with
the loads that you stated.
RE: Spur gear wear
There are greases that are made not to flow, and therefore, not to "wipe" off the surface very easily. Lithium seems to me to have the wrong features for what you are trying to do.
I don't know which one to recommend to you, but I am sure there are other people in this forum who do. Whatever those other ones are, I just know I never wanted them in my bearing assemblies, because they weren't good there.
rmw
RE: Spur gear wear
RE: Spur gear wear
cut by withhold the cutter by .5 x the
addendum and the gear blank would increase
by 1.0 x the addendum. The basic center
distance would change also by .5 x the
addendum.
If your center distance is fixed, you might
try cutting 20 teeth on the same blank as
the 21 tooth blank.
Does the weight remain constant going up
and then down?
How are the 4 different pinions driven?
electric, hydraulic, or whatever?
RE: Spur gear wear
RE: Spur gear wear
You might want to radii the rack
teeth at their tips as they may be
digging into the pinion dedendums.
You might also want to increase the
length of the pinions to make them
stronger. Are the pinion and rack
teeth now the same length. You can
also have the rack teeth tip relieved
if you are having deflection problems.
RE: Spur gear wear
RE: Spur gear wear
With any kind of a failure you need to find the cause. An analytical check of the gears will tell you if you have a manufacturing problem. You should also take a look at your contact conditions.
RE: Spur gear wear
RE: Spur gear wear
You will still have the ductility
because of the softer core.
When you asked about greater life
with a higher hardness, I assumed
that you would Carburize or induction
harden to .045 deep or so to the
flank and root and not overlap at
the tips.