Page 6 - Olipes Industrial Maintenance

Couplings

Couplings are mechanisms entrusted to transfer movement and power between two shafts, while absorbing possible
misalignments, preventing stress which damages the parts of the power train. They may be categorised into rigid or flexible.

Of all the types of existing couplings only the so-called flexible models are greased (sheet/steel mesh or grid, chain, barrel and
crowned toothed gears). Recommendations for lubrication are based on the use of adhesive greases with a high Extreme Pressure
capacity, high resistance of the oil to centrifugation and variable consistencies in accordance with the type of coupling and
manufacturer.
AGMA (American Gear Manufacturers Association) defines three types of greases for couplings in accordance with AGMA 9001-A86
standard: Types CG-1, CG-2 and CG-3. These three types of grease differ in relation to the viscosity of their base oil (greater viscosity for
greater work loads), their dropping point and NLGI consistency, which will vary in accordance with the type of coupling it is intended
for, the diameter and rotation speed of the same.
RECOMMENDATIONS:
You need to take the following recommendations into account when selecting the most appropriate grease in each case:
• We recommend the use of complex aluminium greases. Other formulations may be used, preferably greases with a high polymer
content and a low percentage of soap (complex Lithiums or Calciums).
• Greases with a high anti-wear (AW) and extreme pressure (EP) capacity should be used.
• Solid additives (generally > 5 %) should be used when the couplings are subjected to high loads.
• The grease should be compatible with the seal materials and coupling packagers.
• The viscosity of the base oil and the NLGI consistency of the grease are selected in accordance with the type of coupling and the
working conditions of the same.
• The grease selected should pass the oil separation testing in accordance with test ASTM D4425, given that it should bear
accelerations of up to 10g in extreme working conditions.
• The coupling should be filled with grease up to a maximum of 75% of its capacity or cavity.
Taking these factors into account the major coupling manufacturers recommend:
Lubricating with greases

Grid-barrel couplings

Standard conditions
MAXIGRAS C45 EP

See page 2.
Extreme conditions including aggressive environments
MAXIGRAS 102/1

EP Calcium Sulfonate Complex Grease.
AGMA Type CG-1/CG-2 NLGI 1 DIN KP1R-30 ISO-L-XCFIB-1 V (cSt at 40ºC) > 500 -30ºC to +180ºC
A long-life grease specially recommended for aggressive environments featuring moisture,
loads, vibrations and extreme temperatures.

High loads and vibrations
MAXIGRAS COMPLEX M

EP Complex Grease with solid additives (graphite and MoS ) and high-viscosity base oil.
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AGMA Type CG-1/CG-2 NLGI 2 DIN KPF2P-20 ISO-L-XBEHB-2 V (cSt at 40ºC) > 375 -20ºC to +160ºC (+180ºC)
Specially recommended for barrel couplings subjected to high loads. Prevents problems of
corrosion due to vibration.

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