Nexen RPG-B User manual

FORM NO. L-21274-A-0113
RPG-B, Rotary Drive System
With Bearing
Precision Motion Control
User Manual
SIT S.A. | Tfn. 943 457200 | [email protected] | www.sitsa.es

FORM NO. L-21274-A-0113 2
In accordance with Nexen’s established policy of constant product improvement, the specifications contained in this
manual are subject to change without notice. Technical data listed in this manual are based on the latest information
available at the time of printing and are also subject to change without notice.
Technical Support: 800-843-7445
[phone]
www.nexengroup.com
This document is the original, non-translated, version.
Conformity Declaration: In accordance with Appendix II B of CE Machinery Directive (2006/42/EC):
A Declaration of Incorporation of Partly Completed Machinery evaluation for the applicable EU directives was carried
out for this product in accordance with the Machinery Directive. The declaration of incorporation is set out in writing in a
separate document and can be requested if required.
This machinery is incomplete and must not be put into service until the machinery into which it is to be incorporated has
been declared in conformity with the applicable provisions of the Directive.
Nexen Group, Inc.
560 Oak Grove Parkway
Vadnais Heights, Minnesota 55127
ISO 9001 Certified
Copyright 2013 Nexen Group, Inc.
Read this manual carefully before installation and operation.
Follow Nexen’s instructions and integrate this unit into your
system with care. This unit should be installed, operated and
maintained by qualified personnel ONLY. Improper installation
can damage your system, cause injury or death. Comply with
all applicable codes.
DANGER
SIT S.A. | Tfn. 943 457200 | [email protected] | www.sitsa.es

FORM NO. L-21274-A-0113
Table of Contents
General Safety Precautions --------------------------------------------------------------------------------------------------- 4
System Design Overview:
General System Requirements ----------------------------------------------------------------------------------------- 5
Mounting Requirements---------------------------------------------------------------------------------------------------- 5
Pinion Requirements -------------------------------------------------------------------------------------------------------- 5
Proper System Alignment -------------------------------------------------------------------------------------------------------6
Mounting Surface Details--------------------------------------------------------------------------------------------------------6
Installation:
System Mounting ------------------------------------------------------------------------------------------------------------- 6
Dial Plate Mounting (Output)--------------------------------------------------------------------------------------------- 6
Roller Pinion Installation:
Shaft Mounted Pinion Installation ---------------------------------------------------------------------------------------7
Flange Mount Pinion Installation (ISO 9409) ----------------------------------------------------------------------8
Applying Preload ---------------------------------------------------------------------------------------------------------------- 10
System Alignment Verification --------------------------------------------------------------------------------------------- 11
Disengaging the Roller Pinion ---------------------------------------------------------------------------------------------- 12
Lubrication ------------------------------------------------------------------------------------------------------------------------- 12
Warranty ----------------------------------------------------------------------------------------------------------------------------13
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FORM NO. L-21274-A-0113 4
WARNING
Failure to properly support the load
before disengaging the RPG system
could cause serious harm to operators or
equipment.
DANGER
This product has moving parts that can
crush or cut appendages. Provide
adequate spacing or guarding from any
operating product.
CAUTION
Use lifting aids and proper lifting
techniques when installing, removing, or
placing this product in service.
WARNING
Ensure proper guarding of the product is
used. Nexen recommends the machine
builder design guarding in compliance with
OSHA 29 CFR 1910 “Occupational Safety
and Health Hazards”.
WARNING
Use appropriate guarding for rotating
components. Failure to guard could
result in serious bodily injury.
GENERAL SAFETY PRECAUTIONS
CAUTION
Watch for sharp features when interacting
with this product. The parts have complex
shapes and machined edges.
DANGER
This product has moving parts that
can crush or cut appendages. Provide
adequate spacing or guarding from any
operating product.
WARNING
Use appropriate guarding for rotating
components. Failure to guard could
result in serious bodily injury.
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FORM NO. L-21274-A-0113
SYSTEM DESIGN OVERVIEW
General SyStem requirementS
•Unlike traditional gear systems, the Roller Pinion Gear (RPG) rotary drive system has zero mechanical clearance and
requires a system preload for proper operation. This preload must remain relatively constant around the entire gear
to obtain optimal system performance and life. See Figures 1 and 2 for more details.
•Make sure that the machine design is rigid enough to avoid deflection that could affect the RPG system preload.
•The allowed ring gear concentricity variance tolerances shown in Figure 2 are greater than the system preload. This
is not an error. The RPG system has been designed to operate correctly under these conditions.
•The RPG System generates a reaction force that tries to separate the pinion from the gear teeth. Make sure this is
accounted for in the machine design. See product data for pressure angle specifications.
•The RPG System requires a mechanism to achieve proper pinion preload. It is recommended that the pinion be moved
into the gear not vice versa. The recommended method is to mount the servo drive system on a sliding bracket that
has an adjustment to push it into the gear. Another possible preloading method utilizes a bracket with an eccentric
mounting slot pattern. Nexen offers a preloading mechanism that is easy to integrate into your application as shown
in Figure 11. Spring loaded preloading mechanisms should not be used since the spring force required to counteract
the separation forces are much higher than the allowed preloading force and would cause a reduction in pinion needle
bearing life, and increase system noise. See Figure 11 for more details.
•The RPG System requires periodic lubrication and should use the grease offered on Nexen’s website as an accessory
to the RPG products or equivalent lubrication as described in the Lubrication section on page 16. For more information
or applications with special lubrication needs consult Nexen.
•Do not use the RPG System in environments with temperature outside of -5 to 40º C (23 to 104º F)‚ or with wide
temperature swings since this can affect the preload and meshing of the system. If you have an application with any
of these characteristics consult Nexen.
mountinG requirementS
•Install the RPG-B system at the temperature at which it will be used.
•The ring gear teeth are hardened on the tooth faces only.
•Make sure the machine design is rigid enough to avoid deflection that could affect the ring drive system.
Pinion requirementS
•Verify the shaft variance and diameter tolerances meet Nexen specifications before mounting the pinion. See Figure
3.
•The shaft on which the pinion is mounted on must pass all of the way through the pinion and bushing for proper
support.
•If using a flange mount pinion, verify that the dimensions and tolerances of the gearhead flange meet the specifications
of the ISO 9409 Standard.
•Mount the pinion as close to a support bearing as possible to minimize shaft deflection.
•The pinion roller bearings are sealed. It is still recommended, however, that the pinion be shielded from liquids, dust,
and debris.
•Multiple pinions can drive a gear without an additional service factor but the load sharing by each pinion must be equal.
This is best accomplished with discrete drives linked electronically; mechanically linking pinions is not recommended.
Contact Nexen for more information.
•The RPG system can be operated such that the pinion revolves around the ring gear as long as the pinion preload
remains within specifications as it revolves.
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FORM NO. L-21274-A-0113
PROPER SYSTEM ALIGNMENT
Unlike traditional gear systems, the RPG System operates
with no mechanical clearance and requires a preload. For
optimal performance the preload must remain as constant
as possible as the ring gear travels past the pinion, or
conversely, the pinion orbits around the stationary ring gear.
To achieve this the ring gear and pinion concentricity and
axial variance and pinion axis concentricity and parallelism
to the axis of rotation must be well maintained. The
following guidelines will ensure this is achieved.
1. See Figures 1 and 2.
2. The Pinion axis of rotation must be concentric (±0.02
mm [± 0.0008 in]) to the axis of rotation of the ring
gear and the angle between the Pinion Shaft axis and
the plane the ring gear is in must be exactly 90° (Refer
to Figure 1).
3. The Pinion Shaft must be supported adequately to
ensure full contact of roller pins along the face of ring
gear teeth.
4. Once the RPG-B system is properly installed and
preloaded verify the meshing tooth pattern is correct
as outlined in the System Alignment Verification
section on Page 11.
Gear
90˚
Pinion
Shaft
Axis of
Rotation
This distance must remain
concentric within
0.02 mm [ 0.0008 in]
Figure 1 Pinion Alignment Requirements
Fixed Ring Gear
A
B
.02 mm B
.02 mm A
.02 mm B
.02 mm A
//
Rotating
Mounting
Ring
Axis of
Rotation
Support
Base
Figure 2 Possible Mounting Configurations
Tolerances Allowed In Roller Pinion Setup
Additional dimensional detail can be found in Nexen’s
product drawings.
MOUNTING SURFACE DETAILS
The surface used to mount the RPG-B should be machined
to a flatness of .050mm as shown to ensure proper
alignment. See Figure 1.
All provided provisions for fasteners should be utilized.
Make sure there is proper clearance around the gearbox
as seen in Figure 1.
INSTALLATION
S yStem m ountinG
•Clean and check all mounting surfaces before
assembly. Contamination from dirt or machining burrs
can affect system performance.
•Position the system on the mounting surface. There
are threaded holes available in the bearing to use as
lift points, typically M12 x 1.75.
•To center the system, Nexen recommends using
the OD of the teeth as a reference dimension for
alignment.
•Once the system is in location, install the provided
mounting bolts. Tighten the bolts in a star pattern to
ensure even distribution of load.
D ial P late m ountinG (o utPut )
•The dial plate is designed to be piloted by a series of
dowel pins installed in the plate and that straddle the
male pilot on the ring drive. Drawings are available for
each specific size, which will aid in understanding the
method of piloting the dial plate.
•The dial plates should be mounted using all available
holes. Again, tighten in a star pattern to ensure even
load distribution. It is the responsibility of the customer
to ensure the bolt grade and quantity is sufficient for
the application.
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FORM NO. L-21274-A-0113 7
ROLLER PINION INSTALLATION
Note: There are two pinion mounting styles, shaft or flange
mount. Refer to the following section that applies to
your situation. In either case it is critical to minimize
radial variance. It will effect pinion preload and
positional accuracy throughout the run.
Shaft Mounted Pinion Installation
NOTES:
• Refertoproductdrawingsforshaftdetails.
• Refer to General Design Guidelines and Figures 1
and 2 for Roller Pinion mounting requirements.
• The pinion should be mounted as close to a shaft
supporting bearing as possible to minimize shaft
deflection and obtain optimal performance.
• Theshaftthepinionismountedonmustextendall
of the way through the pinion and bushing for proper
pinion support and maximum torque transmission.
1. Clean the shaft the pinion will be mounted on and verify
that variance is less than ±0.013 mm [±0.0005 in] as
shown in Figure 3.
2. Inspect the shaft, pinion bore and the inner and outer
bushing halves to ensure they are clean and have no
defects.
3. Put oil that does not contain any pressure additives
on the shaft, the tapered part of the bushing and the
bushing bolts as shown in Figure 3. Do not lubricate
the bore of the pinion bushing or shaft where the
bushing contacts it or the torque transmission capacity
of the bushing will be reduced.
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Figure 4 Bushing Installation Details
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4.
Insert the outer bushing half into the roller pinion bore
until it bottoms in the roller pinion body.
5. Insert the inner bushing half into the outer bushing half
(previously inserted into the pinion) while ensuring that
the inner and outer bushing half slots are not aligned
as shown in Figure 4. For RPG32 and below you
will also have to simult
aneously ensure the bushing
bolt through holes align with the pinion bolt holes.
On RPG4 0 and larger the bushing bolts thread into
the other half of the bushing, not the pinion body , so
misalignment is not possible. The threaded holes are
for bushing removal.
NOTE: Ensure that the slots in the two components that
make up the bushing are not aligned as shown in
Figure 4.
6. Insert the shaft into the pinion and bushing bore.
7. Insert the bushing fasteners into the through holes.
Only use the provided bushing fasteners.
8. Locate the pinion on the shaft and lightly tighten the
fasteners to t ake clearance out of all of the bushing
parts but still allow the pinion to be moved axially on
the shaft. P osition the pinion and bushing assembly
on the shaft so that the gap between the gear face and
pinion roller bearing shoulders is even on both sides.
As the bushing fasteners are tightened the pinion
will be drawn slightly in the bushing direction so it is
recommended that the pinion and bushing assembly
be offset axially away from the bushing side 3 - 5 mm
[0.1 - 0.2 in] initially so when the bushing fasteners
are fully torqued the pinion ends up centered on the
gear .
9. Equally tighten the bushing fasteners with 25% of
the recommended tightening torque listed in T able 1.
Start tightening at the top fastener and alternate back
and forth across the face in a st
ar pattern as shown
in Figure 4. Repeat this procedure with 5 0% and
then full torque. An additional 1 or 2 repetitions at
full torque are recommended to ensure all fasteners
have reached their t arget torque values. Progressive
tightening of non-adjacent bushing fasteners is
important to prevent any misalignment of components
while installing the bushing.
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FORM NO. L-21274-A-0113
Table 1 Pinion Bushing Bolt Information
Model Bolt Type Tightening Torque
RPS16 M4 3.5 Nm [30.98 in-lb]
RPS20 M5 7.0 Nm [61.96 in-lb]
RPS25 M6 12.0 Nm [106.21 in-lb]
RPS32 M6 12.0 Nm [106.21 in-lb]
RPS40 M6 12.0 Nm [106.21 in-lb]
RPS4014 M8 38.0 Nm [336.26 in-lb]
Flange Mount Pinion Installation (ISO 9409)
1. Clean the gearhead mounting face and pilot bore,
inspecting for contaminates, burrs, or surface defects
that would interfere with full contact between the
pinion and flange.
2. Using a test indicator, check the rotational flatness of
the face as shown in Figure 5. Position the contact
point of the indicator where the pinion will contact
it. Rotate slowly for a minimum of one complete
revolution and note the total amount of variance.
Pinion Side
Gearhead Side
Figure 7
3. Position the contact point of the indicator at bottom
dead center of the pilot bore as shown in Figure 6.
Rotate slowly for a minimum of one complete turn and
note the amount of total variance in one rotation.
10. Once the fasteners are fully torqued verify the pinion
is centered on the gear. If not, measure the positional
error and then remove the pinion as described in the
Disengaging The Roller Pinion section on page 12.
Repeat the pinion installation procedure and offset the
pinion by the recorded error plus the previous off set
value. When the pinion is fully torqued and properly
centered then verify pinion concentric variation at
the center of the pinion rollers as shown in Figure 9.
Variation on this surface must be less than ± 0.030
mm [±0.0010 in]. 4. If either of the following conditions are true, the
gearhead itself may contribute to excessive pinion
preload variation, a reduction in pinion life and/or
accuracy. The user should consider having the
gearhead re-worked or replaced.
a. The measured total variance of the mounting face is
greater than 0.013 mm [0.0005 in].
b. The measured total variance of the pilot bore wall is
greater than 0.005 mm [0.0002 in].
Note: In some cases an adapter will be required to mount
the pinion on the reducer. If so, proceed with Step
5, if not, skip to Step 13.
5. Clean the adapter flange and pilot where it will contact
the gearhead flange inspecting for contaminates,
burrs, or surface defects that would interfere with full
contact between the adapter and gearhead flange.
See Figure 7.
6. Apply a serviceable thread locking compound to the
adapter mounting screws then assemble the adapter
to the gearhead, leaving the mounting screws snug
but do not tighten at this time.
7. Position a test indicator at bottom dead center of
the pilot bore wall as shown in Figure 8 and zero the
indicator. Rotate the assembly slowly by using the
gearhead input shaft a minimum of one complete
revolution while noting the amount of total indicator
variance and mark the angular location in which the
lowest reading occurs throughout the rotation.
.
Figure 5
Figure 6
CAUTION
Preload must be applied before putting your
system into operation. Refer to APPLYING
PRELOAD to properly set preload for your
RPS system.
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FORM NO. L-21274-A-0113 9
Table 3
Pinion Fasteners Tightening Torque
Nm [in-lb]
RPS 16 (M3x0.5-APEX) 1.5 [13]
RPS 16 (M4x0.7) 5.3 [47]
RPS 20 (M5x0.8) 10 [88]
RPS 25 (M6x1.0) 17.5 [155]
RPS 32 (M6x1.0) 17.5 [155]
RPS 40 (M8x1.25) 40 [354]
RPS 4014 (M10x1.5) 70 [620]
8. If the measured total indicator variance of the adapter
pilot bore is greater than 0.008 mm [0.0003 in], tap
gently on the O.D. of the adapter using a soft hammer
at the angular location in which the lowest reading
occurred. Doing this will shift the center of the adapter
closer to the center of rotation.
9. Repeat steps 7 and 8 until the total measured amount
of indicator variance is 0.008 mm [0.0003 in] or
less.
10. Tighten the mounting screws to 50% of the specified
torque specified in Table 2 in a star pattern that
allows for an even distribution of axial clamping force.
Then repeat the tightening pattern with 100% of the
recommended torque.
11. Re-torque the mounting screws once more to the
full-specified torque value in Table 2 to ensure full
torque has been reached on all fasteners. Tighten in
the same order as above.
12. Repeat inspection Step 7 and verify the variance listed
in Step 8 is achieved after fully torquing the adapter. If
variance is out of specifications the adapter should be
removed inspecting for contaminates, burrs, or surface
defects that would interfere with full contact between
the adapter and gearhead flange. In some cases
indexing the adapter relative to the gearhead flange
can be helpful. Then repeat the adapter installation
procedure starting with Step 5.
Adapter Fasteners Tightening Torque
Nm [in-lb]
ISO 16/20 (M5x0.8) 6.5 [58.08]
ISO 16/25 (M6x1.0) 11.5 [78]
ISO 20/25 (M6x1.0) 11.5 [78]
ISO 20/32 (M6x1.0) 11.5 [78]
ISO 32/40 (M8x1.25) 26 [156]
ISO 40/4014 (M10x1.5) 46 [273]
Table 2
Figure 8
13. Clean the pinion flange and pilot where it will contact
the adapter (if used) or gearhead flange inspecting
for contaminates, burrs, or surface defects that would
interfere with full contact between the pinion and
adapter (if used) or gearhead flange.
14. Apply a serviceable thread locking compound to the
pinion mounting screws and assemble the pinion to
the adapter (if used) or gearhead, leaving the mounting
screws snug but do not tighten at this time.
15. Position a test indicator on the center of the pinion
rollers as shown in Figure 9 and zero the indicator.
Rotate pinion a minimum of one complete revolution
by turning the gearhead input shaft while noting the
amount of total indicator variance and mark the angular
location on the pinion shoulder in which the highest
reading occurs throughout the rotation. When the
pinion is properly centered the concentric variation
at the center of the pinion rollers must be less than ±
0.030 mm [± 0.0010 in].
Figure 9
If the measured total indicator variance of the pinion
rollers is greater than ± 0.030 mm [± 0.0010 in], tap
gently on the O.D. of the pinion using a soft hammer
at the angular location in which the highest reading
occurred. Doing this will shift the pinion center closer
to the center of rotation.
16. Tighten the mounting screws to 50% of the specified
torque specified in Table 3 below in a star pattern that
allows for an even distribution of axial clamping force.
Then repeat the tightening pattern with 100% of the
recommended torque in Table 3.
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FORM NO. L-21274-A-0113
APPLYING PRELOAD
If you would prefer to not design your own pinion
preloading mechanism, Nexen offers a high precision push
bolt preloading system that bolts between the machine
frame and servo reducer to simplify machine design and
achieve optimal results. See figure 10.
Preloading Procedure
Note: Be careful engaging the pinion and servo
assembly to the gear to avoid damaging the gear
teeth or pinion rollers.
1. With a dial indicator mounted on the pinion frame,
measure off the tooth peaks. Move the axis taking
frequent measurements to locate the high spot in
the run. This is where the pinion preloading should
be done to prevent excessive preload from occurring
elsewhere in the run.
2. Apply serviceable thread locking compound to the
pinion preloader slider bolts and install the servo and
preload mechanism. Ensure the preload related bolts
are just loose enough to allow the pinion to be pulled
away from the gear teeth. For the Nexen Preloader
System, this is approximately 0.2 - 0.3 Nm [2 - 3 in-
lbs].
Nexen Precision Pinion Preloader product numbers and
more information can be found at www.nexengroup.com
on any of the RPG pinion pages under accessories in the
left hand column.
To ensure optimal meshing of the roller pins with the gear
teeth, the shaft must be preloaded to 0.010 - 0.015 mm
[0.0004 - 0.0006 in] beyond first contact with teeth.
Figure 10
NOTE: Do not apply excessive preload. Preloading
beyond 0.015 mm [0.0006 in] will decrease product
life, increase noise, and cause vibration. When the
RPG system is properly preloaded, there will be no
tangential play between the gear teeth and the pinion
rollers if the pinion is not allowed to turn and the
rotating assembly forced back and forth in the direction
of rotation.
Refer to Figure 11 for suggested preload methods.
17. Re-torque the mounting screws once more to the full-
specified torque value in Table 3 to ensure full torque
has been reached on all fasteners. Tighten in the same
order as above.
18. Repeat variance inspection Step 15 and verify the
variance listed is achieved after fully torquing the
pinion. If variance is out of specifications the pinion
should be removed inspecting for contaminates, burrs,
or surface defects that would interfere with full contact
between the adapter (if used) and gearhead flange.
Indexing the pinion relative to the adapter (if used) or
gearhead may help in some cases. Repeat the pinion
installation procedure starting with Step 13.
Push Bolt
Figure 11
Adjustment by Oblong Holes
(Preferred Method)
Adjustment by Eccentric Holes
(Option 1)
Adjustment by Shim
(Option 2)
Shim
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FORM NO. L-21274-A-0113 11
Proper roller to tooth meshing can be verified by two
methods depending on which you find easier to interpret:
Option 1: Apply a slow drying machinists dye to the pinion
rollers and move the RPG system back and forth over a
short distance (about 1/2 meter). It is important the dye
remain wet so it transfers to the gear teeth and is not
depleted. Analyze the dye pattern transferred to the teeth.
If the meshing geometry is good the dye will be spread
evenly all the way across the tooth face over the middle
2/3 - 3/4 of the teeth with none at the top and bottom. If
this section is properly aligned clean off dye residue and
repeat as necessary to verify the RPG alignment over the
entire rotation as shown in Figure 12.
Option 2: Apply a small amount of high contrast grease
to each gear tooth face over 1/2 meter of circumference.
Operate the RPG system back and forth over this 1/2
meter of travel. If the meshing geometry is good the
grease will be completely wiped away all the way across
Good Alignment Poor Alignment
Contact Pattern Contact Pattern
Figure 12
the tooth face over the middle 2/3 - 3/4 of the teeth with
some remaining at the top and bottom. If this section is
properly aligned clean off grease with a solvent and repeat
as necessary to verify the RPG alignment over the entire
rotation as shown in Figure 12.
SYSTEM ALIGNMENT VERIFICATION
If the dye or grease contact pattern indicates a meshing
problem, diagnose the problem, correct it, and then repeat
the Applying Preload and System Alignment Verification
procedures.
Table 4
Screw Tightening Torque
Nm [in-lb]
Preloader Screw
All Models - 1.7 [15] Max
Shoulder Screws (Mtg. Plate)
RPS-PRE-064 M8x1.25 40 [350]
RPS-PRE-090 M8x1.25 40 [350]
RPS-PRE-110 M8x1.25 40 [350]
RPS-PRE-140 M8x1.25 40 [350]
RPS-PRE-200 M12x1.75 120 [1060]
Gearhead Screws (Mtg. Plate)
RPS-PRE-064 M4x0.7 5.3 [47]
RPS-PRE-090 M5x0.8 10 [88]
RPS-PRE-110 M5x0.8 10 [88]
RPS-PRE-140 M6x1.0 17.5 [155]
RPS-PRE-200 M8x1.25 40 [354]
Preloader Mtg. Screws (2x)
All Models M6x1.0 17.5 [155]
3. Verify that the pinion rot ational axis is as parallel as
possible to the gears rotational axis, and the gear
is centered between the pinion bearing flanges as
shown in Figure 1.
4. Rotate the preload adjustment screw cloc kwise to
separate the pinion from the gear. T his will ensure
that clearance is initially present. Then seat the pinion
into cont
act by turning the preload adjustment screw
counterclockwise until a slight resist ance is felt and
then back the screw off 1/8 of a turn. T his step is
critical to prepare for preload settings.
5. Place a magnetic base dial indicator on the same part
of the machine as the motor and reducer , and locate
its probe on the OD of the pinion flange suc h that it
measures in the direction of preload travel.
6. Apply the preload of 0.010 - 0.015 mm [0.0004
- 0.0006 in] with the preload application screw(s)
and then tighten the preload lockdown bolts to
their recommended torques. See T
able 4 for Nexen
Preloader System torque values. Typically the preload
will change slightly when the preloader lockdown bolts
are tightened. If tightening the preload bolts causes
the amount of preload to fall outside of specifications,
record how much it changed when tightening the
preloader lock down bolts then loosen the preloading
system and repeat the preloading procedure but
adjust the initial preload (more or less) by the recorded
preload deviation. T
his procedure will ensure that
when the preloader loc kdown bolts are tightened the
amount of preload should fall within specifications.
7 . W ith the pinion preloaded to specifications manually
rotate the gear by hand (if possible) checking for
smoothness and uniformity of resist
ance. If manually
applied motion is not possible, use the servo motor
to rotate the gear, with just enough torque output to
move it while looking and listening for resist ance to
motion.
SIT S.A. | Tfn. 943 457200 | [email protected] | www.sitsa.es

FORM NO. L-21274-A-0113
DISENGAGING THE ROLLER PINION
1. De-couple the load from the RPG system.
2. Disconnect the power source, ensuring that no torque
is applied to the roller pinion.
3. Remove pinion preload by loosening the preload
mechanism sliding bolts slightly and then turning the
preload application screw(s) to remove the pinion
preload. You should be able to slightly separate the
pinion from the gear teeth now.
WARNING
Failure to properly support the load before
disengaging the RPG system could cause
serious harm to operators or equipment.
4. Progressively loosen non-adjacent bushing fasteners
in the same order they were tightened until all are
removed from the bushing (Refer to Figure 4).
5. Insert the bushing fasteners into the threaded holes
in the bushing flange and alternately tighten them as
illustrated in Figure 4 to release the locking action of
the bushing.
6 Lift the servo/reducer/preload mechanism assembly
from the gear or slide the servomotor/reducer out of
the pinion bore.
NOTE: Inspect all bushing fasteners and replace any that
show excessive wear. Contact Nexen for replacements.
OPERATION
DANGER
This product has moving parts that
can crush or cut appendages. Provide
adequate spacing or guarding from any
operating product.
WARNING
Never exceed maximum operating
speeds listed for your product.
WARNING
Ensure proper guarding of the product is used.
Nexen recommends the machine builder
design guarding in compliance with OSHA 29
CFR 1910 “Occupational Safety and Health
Hazards”.
WARNING
Use appropriate guarding for rotating
components. Failure to guard could
result in serious bodily injury.
• MaxspeedofRPS25Pinion=1960rpm.
LUBRICATION
The pinion needle bearings are sealed and lubricated for
life and cannot be serviced.
Nexen recommends lubricating the gear teeth every 2
million pinion revolutions or 6 months, but it may need to
be lubricated more frequently based on the application
conditions, and observable tooth or roller wear.
When lubricating the RPG system inspect the pinion
rollers and gear teeth for any abnormal wear patterns and
ensure the pinion rollers are not seized or have excessive
play. Wear on the edges of the gear teeth (not uniform
across the tooth face) or rings on the rollers indicate an
alignment problem which should be corrected to obtain
maximum system performance and life.
The rollers in new pinions, especially larger sizes, can
seem difficult to turn due to seal drag. This improves as
the pinion breaks in.
THK AFA grease is recommended for gear tooth
lubrication. Nexen offers this grease under product
number 853901. Greases for special applications such
as food grade, vacuum, or others are allowed if they use
a synthetic base, a polyurea thickener, and meet the
followingKinematicViscosityLevels:CST@40C=25;
CST@100C=5.ContactNexenforrecommendations
on alternative greases.
The RPG system can be lubricated in two ways:
1. Apply grease to the pinion rollers and roll the pinion
back and forth 5 times over one meter circumference
of gear teeth, repeating the process until the entire
gear is lubricated.
2. Using a swab apply a very small dab of grease on the
middle of each tooth face and rotate the ring gear 5
times.
Wipe excess grease from the sides of the gear and pinion
body to prevent grease being thrown off during operation
and for general cleanliness.
SIT S.A. | Tfn. 943 457200 | [email protected] | www.sitsa.es

FORM NO. L-21274-A-0113
Nexen Group, Inc.
560 Oak Grove Parkway
Vadnais Heights, MN 55127
800.843.7445
Fax: [phone]
www.nexengroup.com
ISO 9001 Certified
WARRANTY
Warranties
Nexen warrants that the Products will (a) be free from any defects in material or workmanship for a period of 12 months
from the date of shipment, and (b) will meet and perform in accordance with the specifications in any engineering drawing
specifically for the Product that is in Nexen’s current product catalogue, or that is accessible at the Nexen website, or that is
attached to this Quotation and that specifically refers to this Quotation by its number, subject in all cases to any limitations
and exclusions set out in the drawing. NEXEN MAKES NO OTHER WARRANTY, EXPRESS OR IMPLIED, AND ALL
IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. This warranty applies only if: (a) the Product
has been installed, used and maintained in accordance with any applicable Nexen installation or maintenance manual
for the Product; (b) the alleged defect is not attributable to normal wear and tear; (c) the Product has not been altered,
misused or used for purposes other than those for which it was intended; and (d) Buyer has given written notice of the
alleged defect to Nexen, and delivered the allegedly defective Product to Nexen, within one year of the date of shipment.
Exclusive Remedy
The exclusive remedy for the Buyer for any breach of any warranties provided in connection with this agreement will be,
at the election of Nexen: (a) repair or replacement with new, serviceably used, or reconditioned parts or products; or (b)
issuance of credit in the amount of the purchase price paid to Nexen by the Buyer for the Products.
Agent's Authority
Buyer agrees that no agent, employee or representative of Nexen has authority to bind Nexen to any affirmation,
representation, or warranty concerning the Products other than those warranties expressly set forth herein.
Limitation on Nexen’s Liability
TO THE EXTENT PERMITTED BY LAW NEXEN SHALL HAVE NO LIABILITY TO BUYER OR ANY OTHER PERSON
FOR INCIDENTAL DAMAGES, SPECIAL DAMAGES, CONSEQUENTIAL DAMAGES OR OTHER DAMAGES OF
ANY KIND OR NATURE WHATSOEVER, WHETHER ARISING OUT OF BREACH OF WARRANTY OR OTHER
BREACH OF CONTRACT, NEGLIGENCE OR OTHER TORT, OR OTHERWISE, EVEN IF NEXEN SHALL HAVE
BEEN ADVISED OF THE POSSIBILITY OR LIKELIHOOD OF SUCH POTENTIAL LOSS OR DAMAGE. For all of
the purposes hereof, the term "consequential damages" shall include lost profits, penalties, delay damages, liquidated
damages or other damages and liabilities which Buyer shall be obligated to pay or which Buyer may incur based upon,
related to or arising out of its contracts with its customers or other third parties. In no event shall Nexen be liable for any
amount of damages in excess of amounts paid by Buyer for Products or services as to which a breach of contract has
been determined to exist. The parties expressly agree that the price for the Products and the services was determined
in consideration of the limitation on damages set forth herein and such limitation has been specifically bargained for and
constitutes an agreed allocation of risk which shall survive the determination of any court of competent jurisdiction that
any remedy herein fails of its essential purpose.
Inspection
Buyer shall inspect all shipments of Products upon arrival and shall notify Nexen in writing, of any shortages or other failures
to conform to these terms and conditions which are reasonably discoverable upon arrival without opening any carton
or box in which the Products are contained. Such notice shall be sent within 14 days following arrival. All notifications
shall be accompanied by packing slips, inspection reports and other documents necessary to support Buyer's claims. In
addition to the foregoing obligations, in the event that Buyer receives Products that Buyer did not order, Buyer shall return
the erroneously shipped Products to Nexen within thirty (30) days of the date of the invoice for such Products; Nexen
will pay reasonable freight charges for the timely return of the erroneously shipped Products, and issue a credit to Buyer
for the returned Products at the price Buyer paid for them, including any shipping expenses that Nexen charged Buyer.
All shortages, overages and nonconformities not reported to Nexen as required by this section will be deemed waived.
Limitation on Actions
No action, regardless of form, arising out of any transaction to which these terms and conditions are applicable may be
brought by the Buyer more than one year after the cause of action has accrued.
SIT S.A. | Tfn. 943 457200 | [email protected] | www.sitsa.es