Nexen RPG25A-GE486T 966740 - Manual (Page 17)

17 FORM NO. L-21235-G-0413
LUBRICATION
The pinion needle bearings are sealed and lubricated for
life and cannot be serviced.
Nexen recommends lubricating the rack or individual roller
contacts every 2 million pinion revolutions or 6 months,
which ever comes first, but it may need to be lubricated
more frequently based on the application conditions, and
observable tooth or roller wear.
When lubricating the RPS system inspect the pinion rollers
and rack teeth for any abnormal wear patterns and ensure
the pinion rollers are not seized or have excessive play.
Wear on the edges of the rack 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 AFC is the recommended grease for rack tooth
lubrication although THK AFA grease can also be
used. Both can be found on the RPS product pages of
Nexen’s website under accessories. 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 RPS 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 of rack,
repeating the process for each meter of rack.
2. Using a swab apply a very small dab of grease on the
middle of each tooth face and roll the pinion back and
forth over the entire length of the run 5 times.
Wipe excess grease from the sides of the rack and pinion
body to prevent grease being thrown off during operation
and for general cleanliness.
Maximum RPS system life will be obtained by following
the recommended lubrication intervals as stated above.
In some special applications the Premium and Endurance
models of RPS rack can be operated lubrication free if
the maximum speed does not exceed 0.5 m/s [1.64 ft/s].
Typically lubrication free applications involve:
• Dirty environments where contaminates will be
attracted/stick to the lubricant on the rack creating
mechanical interference or an abrasive paste that can
accelerate wear.
• Food processing
• Clean rooms or applications where very low particle
emissions are desired
• Vacuum environments
• Applications where periodic servicing is problematic
If the RPS System is run lubrication free there will be some
reduction in life of the RPS system which will vary widely
depending on the application. The Standard and Universal
models of RPS rack cannot be run lubrication free under
any circumstances. Contact Nexen for more information.