adhesives and lubricants should be selected as an integrated tribological/assembly system, because lubricant chemistry, substrate, clearance, temperature, and cure conditions can strongly affect adhesive performance.
1. Adhesive Solutions (Rigid Joining, Retaining & Sealing)
In bearing and gear assemblies, adhesive compounds prevent relative micro-movement, fretting corrosion, and fluid leakage under dynamic shock loads and vibration.
Core Adhesive Technologies & Applications
- Retaining Compounds (Anaerobic Acrylics):
- Primary Function: Securing cylindrical joints (e.g., locking bearing outer races into housings or gear hubs onto shafts). They cure in the absence of air and presence of metal ions to fill micro-gaps.
- Key Benefit: Eliminates fretting corrosion, eliminates the need for expensive high-precision interference fits, and provides 100% surface-to-surface contact.
- Threadlockers & Thread Sealants:
- Primary Function: Locking threaded fasteners securing bearing retaining rings, flange bolts, and gear housings against vibration-induced loosening.
- Key Benefit: Replaces mechanical lock washers and seals against fluid pressure up to high bursting pressures.
- Structural Adhesives (Epoxies, Polyurethanes, UV-Curing):
- Primary Function: Permanent structural bonding of composite/hybrid gears, magnet bonding in electric motor rotor assemblies, and encapsulation of sensor-integrated smart bearings.
- Key Benefit: High shear and impact strength with broad thermal performance ranges (-55°C to +180°C+).
- Liquid Gasketing (Anaerobics & RTV Silicones):
- Primary Function: Sealing gearbox flanges, split housings, and bearing cover plates.
- Key Benefit: Prevents lubricant leaks, resists synthetic gear oils, and avoids gasket compression set over time.
2. Lubricant Solutions (Friction & Wear Reduction)
Lubricants establish a protective elastohydrodynamic (EHD) or hydrodynamic film between rolling elements, gear teeth, and raceways to prevent metal-to-metal contact.
| Lubricant Type | Base Chemistry / Forms | Primary Application & Performance Characteristics |
| Lubricating Greases | Base oil (mineral/PAO/ester) + Thickener (Lithium Complex, Polyurea, Calcium Sulfonate) | Best for: Sealed-for-life bearings, open gear sets, low-to-medium speed applications. Features: Stays in place, acts as a secondary seal against contamination, reduces maintenance frequency. |
| Gear & Industrial Oils | Synthetic (PAO, PAG, Ester) or Mineral Base Oils + EP/AW Additive Packages | Best for: High-speed gearboxes, enclosed gear drives, heavy-duty industrial bearings. Features: High heat dissipation, continuous fluid circulation, superior film thickness under heavy loads. |
| Solid/Dry Film Coatings | MoS₂ (Molybdenum Disulfide), PTFE, Graphite | Best for: Extreme temperatures, vacuum environments, dry start-up protection, non-stick gear teeth. Features: Prevents galling and seizure where liquid lubricants wash out or evaporate. |
Key Selection Criteria
When specifying adhesive and lubricant chemistry for drive systems, consider the following technical variables:
- Operating Temperature Range: Ensure the lubricant base oil or adhesive polymer matrix maintains mechanical integrity under peak thermal loads.
- Load & Surface Velocity (Pitch Line Velocity / DN Factor): High-speed bearings require low-viscosity oils to minimize fluid friction, while heavy shock loads require extreme-pressure (EP) additives in greases.
- Chemical Compatibility: Check compatibility between synthetic lubricants (e.g., PAG oils) and anaerobic adhesives, elastomer seals, and non-ferrous gear materials (e.g., bronze worm gears).
- Assembly Clearances: Match anaerobic retaining compound viscosity to the diametral clearance (e.g., low viscosity for press fits <0.05 mm; high viscosity for slip fits up to 0.25 mm).