Help - how do I tear down a Siemens 1HU3056 DC servo?
Looking in thru the brush holder with the brushes removed I can see that the commutator needs some attention. I have removed the 4 nuts on the main body bolts and the 4 screws thru the nose casting that pull in the front bearing retainer and then removed the front nose casting from the motor body. I have also removed the rear cover and the rear casting with the position sensor mounted in it. The main motor housing with the field pieces has been slid off of the armature. Finally, I removed the ring that holds the tach generator brushes. The armature and brush housing and the tach generator are now out and on the bench as an assembly.
The armature is still held firmly in position in the brush housing casting. It spins freely in the bearing but it does not move axially. Either the rear bearing is pressed onto the armature and retained in the housing by a press into the housing, or the tachometer generator is retained on the rear end of the armature shaft preventing the armature from being pulled out of the brush housing. Clearly the motor tachometer rotor is too large to slide thru any armature bearing and clearly it must be removed before the motor can be disassembled further.
So, how is the tach generator retained on the armature shaft and how do I remove it?
There is a hex on the rear of the armature shaft. Is this hex a feature machined into the armature shaft itself and not removable, or is it a second part that can be unscrewed from the armature shaft? If so does this part retain the tach generator?
The ID of the tach generator appears to be larger than the hex on the rear of the armature shaft. Does the tach generator simply slide over the hex and press onto the armature shaft? If so, how do I get a hold on it to pull it back off the armature shaft? Do I simply press on the shaft end while holding the brush casting against the press force? What is the acceptable process to remove the tach generator?
Once the tach generator is removed, does the brush housing simply slide off the armature or do I have to pull that apart too? Will the rear bearing be damaged in the process and need to be replaced?
When I get it all apart, I will turn the commutator and reassemble these parts. Any advice on tool geometry for turning the commutator?
Then I want to install an electric brake in between the tach generator and the position encoder and make a new rear shaft extension for driving the brake and the position sensor.
Out of curiosity, is there some special fixture used to hold the motor body (field section) while pulling the armature from the main motor field housing that keeps the armature centered in the field pole pieces and prevents the armature from making contact with the field poles? If they make contact is the motor demagnetized and ruined?
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