How to disassemble gearbox?

[Sypher]

I would like to disassemble the gearbox, replacing all bearings/seals and remove rust from the shaft. Could someone give me an idea on how to go about disassembling it? For example, how would I remove the shaft? Does it twist off or pull off? Looking at the bearings, there is no way to get a puller anywhere. It is a full metal casing from a QUANTUM 600.

I am trying to fully rebuild the motor and gearbox. I could probably do fine w/o replacing the bearings inside the gearbox; however, I would like to if possible.

 

[ashtree]

Sypher

Have the bearings failed or are you just doing preventative maintenance?
How are the gears attached to the shaft? The gear that mates with the worm drive looks to have a circlip holding it in position. Does it have keyways as well?
Can you give us a picture of the other side of the housing?

Without knowing anything else i would think you will have to press the shaft through the gears after removing circlips and grubscrews etc. I would push from the end that has the long shaft protruding from the housing and try to pop the bearing out of the back side and the shaft through the bearing on the side that you can see. The gears will stay inside and you would have to press the shaft through them as well, at least for a start.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[dicer]

Need way more pictures, and clean out the grease so we can see stuff.

 

[tygerdawg]

It's been a number of years since I worked on something similar, but IIRC the shafts are made with steps to help lock & set the position of the gears & bearings. Gears were pressed onto the shafts with an arbor press or similar to make a shaft+gear assembly. Probably used keyways of some sort. The shaft+gear assemblies inserted into the gearbox housing holes. Bearings then pressed over the shafts and seated into the bearing pockets in the gearbox housing. You need a good arbor press and perhaps some spacers or other bits that will give you a means of reversing the assembly process: press out the bearings, remove the shaft+gear assemblies, press off the gears from the shafts.

Of course I always reserve the right to be wrong.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[flexoprinting]

Good Morning Sypher

This thread really should be posted in mechanical forum.

However, you can make your own puller.Can't tell from the pic.'s but assuming there is only
one access hole on each side of your box and no retaining rings in housings. It appears one gear is spring loaded and the other has a retaining ring, the gears should come off fairly easy since the box was sealed and bathed with lube.

You will need two plates of steel ~ 1/2 thick.
The bottom plate hole needs to be just larger than bearing O/D and smooth to surface of case.
The top plate needs a hole slightly larger than O/D of shaft.Drill and thread top plate for 1/4x20 or 5/16x18 thread, two holes will do four would be better.
Have bottom plate aligned so bearing will pull through it.
Place top plate over shaft and bolt/with a robust washer on end of shaft and simply apply
even pressure to all screws, screw bottoms press on lower plate of steel preventing damage to case.

Chuck

 

[dArsonval]

Politely "echoing" flexoprinting/Chuck... that the topic would be better served in a mechanical forum.
tygerdawg also provides useful feedback.

To answer the original question of, "...how to go about disassembling it?"

The first place to start, would be to acquire a valid drawing of the internal assembly.
It serves as an aid in determining how the components mate with each other.
Obtaining a drawing is not always possible as may be the situation with this gearbox.

The next thing you'll need is access to some type of press.
An arbor press may be useful, and better yet, an H Frame Hydraulic Shop Floor Press.
You will also need pieces of random sizes of steel material (pieces of key stock, thick
washers, or even specifically shaped steel items) to provide the necessary support when
pressing on components to get them to move/separate from each other.
This would also include cylindrical shaped items to be used in pressing shafts
entirely through mating gears.
(You'll need additional items for re-assembly of the gears and bearings back in place.)

You may need a source of heat. A portable oxy acetylene torch set for example.

And in all this talk relating to "pressing", you'll also have to remain mindful
of the gearbox housing. It appears to be made from cast aluminum which may crack
and break if something is not adequately supported during a pressing operation.

Having said all of the above, what you'll need most... is time.
For if you've not taken the item apart before, and this is the first gearbox you've
attempted to dismantle, you're going to need ample patience coupled to that time as well.

There's always the rarity where the items might be knocked apart using a large mallet,
soft face hammers, and so on... because of possible loose gear-fit/bearing fit tolerances.
And the gearbox is not that large/heavy to handle manually, so that's in your favor.

Less I forget, you may even need a flashlight to carefully see how your press/support items
are placed during the pressing operations.
And.... Perhaps the most important item you'll need?
Please wear eye protection.

Good Luck!

John

 

[FreddyZ]

Is it broken?

If it ain't broke, don't fix it.

Wash out the grease with solvent such as kerosene, parts cleaner, etc.

If the rust really bothers you I suggest Evapo-Rust or the equivalent to eliminate it.

Then verify smooth operation and reassemble.