Duff-Norton Ball Screw Translating - Manual (Page 5)

5
2-2. Rebuild Procedure
Duff-Norton recommends the following proce-
dures for assembly and disassembly of 2800 and
9800 Series actuators.
1. Tag critical parts to facilitate reassembly.
2. Mark all mating surfaces to ensure proper
meshing.
3. Clean and lubricate all parts as required.
4. All seals must be replaced when rebuilding.
5. All screws, washers and other small common
parts must be replaced if damaged in any way.
6. Replace damaged or frozen lubrication fittings
with new ones.
2-3. Required Tools
A bearing puller and press, soft jaw table clamp
and common hand tools are necessary for proper
assembly and disassembly.
2-4. Disassembly
Refer to Figure 3-1. When a numerical index
number is referred to, the reference is to Figure 3-1.
Note
Disassembly should be accomplished on a clean
cloth. This is particularly important when disassem-
bling the ball nut assembly (7).
Disassemble as follows:
1. Remove any attachments that may be fastened
to the end of the ball screw (6).
2. Loosen and remove set screws (1) in shell cap
(2) and remove the shell cap from shell (3).
Note
It may be necessary to break shell cap (2) loose
with a hammer.
3. Remove the top load bearing (4) from the shell
cap (2).
Note
It is very important that the ball screw (6) not be
allowed to run out of the ball nut assembly (7).
At this point, it is advisable to wrap tape around
the last few ball screw threads to prevent this
from happening.
4. Remove the bottom pipe (5) from the shell (3).
5. Grasp the top end of the ball screw (6) remove
it, with the ball nut assembly (7) and worm gear
assembly from the shell (3).
6. Remove the bottom load bearing (8) which may
be attached to either the shell (3) or worm gear
(10).
Note
Use only a soft face hammer to tap bearings
loose.
7. If the ball nut assembly (7) or the worm gear
(10) appears to be worm or damaged, disas-
semble these parts from each other. To do this,
lightly clamp ball nut in a table clamp just tight
enough to prevent it from turning.
Note
Care should be taken not to damage the ball
guides.
8. Remove the set screws (9) form the worm gear
(10).
9. Unscrew (counter-clockwise) the worm gear (10)
from the ball nut assembly (7). It will usually be
necessary to use a large wrench on the gear to
break these two pieces apart. If it is desirable to
save the worm gear, a strap wrench should be used.
10. When the worm gear (10) is free from the ball
nut assembly (7), remove the retaining disc (13).
Slide the worm gear off the ball screw (6) and
replace the retaining disc on the screw.
Note
Care should be taken to prevent the screw from
running out of the ball nut.
11. Unscrew the four cap screws (14) from each of
the worm flanges (16) and remove the flanges.
Take care not to lose the flange shims (17).
12. Press the oil seal (18) out of each worm flange
(16).
13. With a soft face hammer, drive the worm (19)
and worm bearing (20) out of the shell (3) by
striking one end of the worm.
14. If the worm (19) or worm bearings (20) are worn
or damaged, remove the worm bearings with a
puller or press.
2-5. Cleaning
1. Use degreasing solvent to remove dirt, grease
or oil from all parts. Be sure to flush the ball nut
assembly (7) thoroughly while running the
assembly along the screw shaft (6) several
times.
Warning
Provide adequate ventilation during the use of
cleaning agents; avoid prolonged breathing of
fumes and contact with skin. Read and follow
manufacturer's instructions.
2. Use clean water or soap solution of 1/4 pound of
soap chips to one gallon of hot water for general
cleaning of painted surfaces.
3. Dry parts thoroughly with moisture-free com-