Gearbox mystery

I need help identifying this gearbox please. It is driven by a 48vdc motor. It's off of a 7700 lb automated forklift (AGV) manuf by HK Systems.
5 years ago the gearbox new was $5,000. Now they want $5,400 to repair it. It works but it's very noisy. The lube is 80 wt synthetic. There are no obvious signs of wear on any of the gears, it's just got a loud metallic hollow sound, like it's running dry but there's plenty of fresh lube. We sent one in and had it repaired by HK and they just told me the price. I need another option like finding someone who carries the parts or can inspect it and tell me why it's so loud. The gear ratio is 4:1.
There are numbers on the different castings but no manufacturer identification. We suspected it might be a forklift tranny but I had a 25-year forklift repairman tell me he had never seen anything like it on a forklift.

Thanks for any input
Roy

Well you do not quanitfy what noisy is. Noise is defined in industrial hygiene as unwanted sound. What is increase in noise measured by sound level meter at say five feet from machine?

Also those appear to be straight cut gears. Provided you have no metal filings in gearcase or other signs of gear wear you may be best off leaving well enough alone.

Dan Bentler

Thanks Dan, there were no filings or glitter in the oil. I don't have a sound meter but it's noisy enough to turn peoples heads when it drives past them. I have 4 of these machines and it's noisy enough to stand out from the crowd and sound like it needs serious maintenance. I wish I could leave it alone but I'm charged with keeping it in what 'sounds' like good working order and right now it don't.

Well, its a planetary gear box featuring spur gears (not helical) so they are noisier. Do you have specifications on it, like how much gear lash, input to output is acceptable? Whats the torque spec for the driving motor?

As long as warranties are expired, I'd select an off-the-shelf gear box and task our mechanical designer with designing up the adapter details to bolt the new one into where this one goes and to fit the motor. Of course, we've got a CMM and complete machine shop so its pretty easy to reverse engineer and machine up the new details and at that price it would be worthwhile for us.

Thanks. I have no specs or tolerance numbers.
The motor is Ohio Motor, 2400 RPM, frame: A180.
HP:"SPEC".
Model no: A-182299X9166

OK so you are judging noise by people noticing it or finding it distracting or irritating. Can be good criteria especially if machine is run in a dead quiet warehouse.



Personally I prefer forklifts to be noisy so they cannot sneak up on me but after seeing a few operators habits and a few forklift accidents I think a little paranoia is good.

Noise elimination or reduction in machines I think is a black art. I have had nothing wrong with something everyone thought was making the noise but then we found the noise was migrating and came from something else. So your noise just may not be the gearbox.

How hot does gearbox run?

You may be able to lower noise by going back to the old 90W gear oil from the synthetic - the synthetics are thinnner in my opinion - good lubricant and have a lot of good things going for them I think but they are not a magic solution for all problems.

A poor comparison I know but maybe food for thought - most road noise is not windage or the engine or transmission but the tires. Granted the machine is not doing 50 or 60,,, but,,,,.

From John Steinbeck Grapes of Wrath "that rear end whines like a banshee put in another hand full of sawdust" I dont recommend this but it is kinda good for a grin.

Dan Bentler

You might want to try contacting Ohio Motor (could be these guys
http://www.ohioelectricmotors.com/default.aspx )
and see if they recognize the gear box or have suggestions for replacement.

It's a very quiet indoor office environment. This gearbox is noticeably louder than the others even by spinning it by hand on the bench. The tires are 5 inch wide slicks, solid rubber, real smooth and it travels at walking speed only. Gearbox is warm to the touch and feels like the other 7 that are running quiet. I will try Ohio and see what they can tell me, thanks again.

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