Oil Pump Bearings (Needle Roller Bearing + Solid Lubricant)
Characteristics: Full-complement needle roller set (no cage) with embedded solid lubricant (MoS₂, graphite, or PTFE) in raceway pockets or as a transfer film. Designed for boundary / mixed lubrication conditions in engine, transmission, or EV oil pumps.
Advantages:
· Lifetime: Standard needle bearings rely on a continuous oil film – cold starts or cavitation cause dry running and failure within minutes. Solid-lubricant needle rollers survive >10,000 dry starts without scuffing, extending pump life to match engine overhaul intervals (300,000 km).
· Speed: Achieves 12,000 rpm in variable-displacement pumps vs. 6,000 rpm for standard caged needle bearings (solid lubricant eliminates cage fracture and prevents roller seizure under oil starvation).
· Specifics: Eliminates high-pressure oil priming; allows bidirectional pump rotation; reduces system oil demand.
· Application/Industry: Internal combustion engine oil pumps, electric oil pumps in EV gearboxes, hydraulic pumps for off-highway vehicles.
Technical ceiling:
· Dynamic load rating: 30 kN for 20 mm shaft size (full complement).
· Limiting speed: 5,000 rpm dry, 12,000 rpm with oil mist assist.
· Temperature range: -50°C to +250°C (depends on solid lubricant binder).
· Solid lubricant wear life: 1,000 hours intermittent dry operation.
Cautions:
· Standard caged needle bearings cannot be directly replaced - the cage will melt or fracture under dry running; use only full-complement solid-lubricant needles.
· Shaft must be hardened to ≥58 HRC; softer shafts gall against the solid lubricant film.
· If oil is present, choose oil-compatible solid lubricants (e.g., MoS₂ with oil retention); some PTFE-based lubes wash away.
· Not for continuous high-speed dry running (>30 seconds) – only intermittent dry starts.
· Increase radial clearance by 0.02–0.05 mm compared to standard oil-lubricated needle bearings to accommodate lubricant transfer film.
