24
ROSSI
GEARMOTORS
UT.D 123 rev. 3
1) The presence on gear reducer of backstop device is stated by the arrow near the low
speed shaft, indicating the free rotation.
breaker is unsuitable since its threshold must be set higher than the motor
nominal current of rating.
Connect thermal probes, if any, to auxiliary safety circuits
.
Use varistors and/or RC filters to limit voltage peaks due to contactors.
Fuses do not prevent from voltage peaks.
With non-electric motors (i.e. hydraulic motors) install torque limiters (i.e.
max pressure valves) and do not exceed n
1
= 1 500 min
-1
.
Verify that the above mentioned accessories comply with
application zone.
When gear reducer is equipped with a backstop device
1)
, provide a protec-
tion system where a backstop device breaking could cause personal injury
or property damage.
In polluting surroundings,
take suitable precautions against
lubricant contamination through seal rings or other
.
When the gear reducer or gearmotors is over painted, use
antistatic paint and
do not exceed the total thickness
of 200
μ
m
checking the thickness of the primer before
painting again; check again the total thickness of paint,
measuring at several different points.
Gear reducers and gearmotors should be protected by appropriate
means from solar radiance and extremes of weather
.
If it is necessary to run the gear reducer or gearmotor with ‘free’ shafts,
securely fasten the key in the keyway.
For running at ambient temperature greater than +40 °C or less than 0 °C,
consult ROSSI MOTORIDUTTORI.
5.2 - Fitting of components to shaft ends
It is recommended that the holes of parts keyed onto shaft ends should be
machined to H7 tolerance; for high speed shaft ends having D
55 mm,
tolerance G7 is permissible provided that the load is uniform and light; for
low speed shaft end having D
180 mm, tolerance must be
K7
if load is
not uniform and light.
Before mounting, thoroughly clean mating surfaces and lubricate against
seizure and fretting corrosion.
Attention!
Installation and removal operations should be carried out with
the aid of
jacking screws
and
pullers
using the tapped hole at the shaft
butt-end (see table in fig. 2) taking care to avoid impacts and shocks which
may
irreparably damage
the
bearings,
the
circlips
or other parts or cause
sparks; for H7/m6 and K7/j6 fits it is advisable that the part to be keyed is
preheated to a temperature of 80
100 °C.
The couplings and pulleys having a tip speed on external diameter up to 20
m/s must be statically balanced; for higher tip speeds they must be dyna-
mically balanced.
Where the transmission link between gear reducer and machine or motor
generates shaft end loads (see fig. 3), ensure that:
– loads do not rise above the values of the design of application;
– transmission overhang is kept to a minimum;
– gear-type transmissions must guarantee a minimum of backlash on all
mating flanks;
– drive-chains should not be tensioned (if necessary – alternating loads and/
or motion – foresee suitable chain tighteners); if the peripheral speed of
the chain is greater than 1 m/s it is necessary to install proper malfunction
markers such as aligning sensors, etc.
– drive-belts should not be over-tensioned.
Incorrect
Correct
Incorrect
Correct
UT.C 117
U
T.C
666
Fig. 3
Use belts with bleeder resistance to mass
10
9
.
If there is fan on the gear reducer verify
that there is sufficient space allowing for
adequate circulation of cooling air also
after fitting coupling protection. If a cou-
pling protection is fitted (drilled case or
wire netting), smooth, the coupling hub,
if necessary.
5.3 - Shaft mounting
When shaft mounted, the gear reducer must be supported both axially
and radially (also for mounting positions B3 ... B8) by the machine
shaft end, as well as anchored against rotation only, by means of a
reaction having
freedom of axial movement
and sufficient
clearance
in its couplings
to permit minor oscillations always in evidence without
provoking dangerous overloading on the gear reducer.
Lubricate with proper products the hinges and the parts subject to
sliding; when mounting the screws it is recommended to apply locking
adhesives.
For the mounting of the «kit using reaction disc springs» (sizes
125
parallel shafts) use the tapped butt end hole on the shaft end of the dri-
ven machine and the flat machined chamfered surface for compressing
and fitting the disc springs into the reaction recess.
Concerning the reaction system, follow the project indications stated in
the technical catalogues ROSSI MOTORIDUTTORI. Whenever personal
injury or property damage may occur, due to gear reducer fall or pro-
truding pents provide
adequate supplementary protection devices
against:
– rotation or unthreading of the gear reducer from shaft end of driven machi-
ne following to accidental breakage of the reaction arrangement;
– accidental breakage of shaft end of driven machine.
5.4 - Hollow low speed shaft
For machine shaft ends onto which the hollow shafts of gear reducers
are to be keyed, h6, j6, and k6 tolerances are recommended, according
to requirements (duty type, overloads, etc.).
Important!
The shoulder diameter of the shaft end of the driven machi-
ne abutting with the gear reducer must be at least 1,18
1,25 times the
internal diameter of hollow shaft. For other data on machine shaft end,
in case of standard hollow low speed shaft, stepped shaft, with locking
rings or bush, with shrink disc see ROSSI MOTORIDUTTORI technical
catalogues.
When assembling a hollow low speed shaft gear reducer verify that the
hollow shaft is in line with the machine shaft end.
Attention!
For
vertical ceiling-type
mounting and only for
gear reducers equipped with locking rings or bush, gear redu-
cer support is due only to friction, for this reason it is advisa-
ble to provide it with a fastening system.
When
installing
and
removing
gear reducers and gearmotors with hollow
low speed shaft incorporating a circlip groove – whether with keyway or
shrink disc – proceed as per fig. 4a and 4b, respectively, on page 40.
In order to remove the hollow low speed shaft of the parallel and right
angle shaft gear reducers (this is the first operation to perform when
disassembling the gear reducer) turn the shaft until the keyway is fac ing
the intermediate shaft as indicated in fig. 5 and push the shaft from the
reference groove side (circumferencial keyway on shaft shoulder).
The system shown in fig.
4c and 4d, page 40, is good
for
axial fastening
; when
the shaft end of the driven
machine has no shoulder
(as in the lower half of the
drawing - fig. 4d) a spacer
may be located between
the circlip and the shaft end
itself. Parts in contact with
the circlip must have sharp
edges.
The use of
locking rings
(fig. 4e, page 40) or
locking bush
(fig.
4f page
40), will permit easier and more accurate installing and removing and
eliminate backlash between the key and keyway.
The locking rings or bush are fitted after mounting and after having
carefully degreased the coupling surfaces. Do not use molybdenum
bisulphide or equivalent lubricant for the lubrication of the parts in con-
tact. When tightening the bolt, we recommend the use of a
locking
adhesive
.
Respect the tightening torques stated in the table 11b.
In case of axial fastening with locking rings or bush – especially
when having heavy duty cycles, with frequent reversals – verify,
after some hours of running, the bolt tightening torque and event-
ually apply the locking adhesive again.
When fitting with
shrink disc
(fig. 4g, page 40) proceed as follows:
– carefully degrease the surfaces of hollow shaft and shaft end of driven
machine to be fitted;
Fig. 5
groove side
opposite side to groove
UT.C 322
D
d
Ø
Ø
11
00
M 5
14
19
M 6
24
28
M 8
30
38
M 10
42
55
M 12
60
75
M 16
80
95
M 20
100
110
M 24
125
140
M 30
160
210
M 36
240
320
M 45
Shaft end
Fig. 2
U
T.C
886
