6311‑ZZ Deep Groove Ball Bearing 55x120x29 Double Metal Shield ZZ Non‑Relubricatable

1. Product Overview

6311‑ZZ is single‑row deep groove ball bearing, dimension 55 mm bore × 120 mm OD × 29 mm width.
Suffix explanation:
‑ ZZ: Double‑sided non‑contact metal dust shields, retain factory pre‑filled grease, block solid dust particles, maintenance‑free design, cannot resist liquid splash.

Adopt deep raceway structure, can bear bidirectional radial load plus moderate bidirectional axial load. Stamped steel riveted cage separates GCr15 chrome‑steel balls for low‑friction, low‑noise high‑speed running. Whole rings are fully quenched bearing‑steel. Widely used for medium‑large industrial motors, fans, water pumps, reducers, conveyor rollers and general‑purpose machinery working under dry‑dust environment.

2. Technical Specifications

Mounting‑shoulder drawing and performance test reports can be provided upon customer request.

3. Core Advantages

• Double‑sided ZZ metal non‑contact shields: Small rotation resistance, no extra friction loss; lock built‑in grease, block dry solid dust, achieve long‑term maintenance‑free operation.
• Classic deep‑groove ball‑bearing structure, bears radial load and moderate bidirectional axial load, fits composite‑load transmission shafts of general‑purpose equipment.
• Super‑finished raceway and steel‑ball surface, low vibration & low‑noise performance, stable continuous‑running performance for medium‑large‑motor‑class equipment.
• GCr15 overall quenched steel, stable metallographic structure, good anti‑fatigue and wear‑resistant performance for cyclic working conditions.
• Stamped‑steel riveted cage, light‑weight and high rigidity, evenly distribute rolling‑element stress and lower high‑speed noise.
• Standard ISO metric dimension, fully interchangeable with global 6311‑ZZ bearings, direct replacement without modifying original housing.
• Non‑contact shield structure brings higher limiting speed compared with rubber contact seal bearings.
• Rich custom options: P0/P6/P5 precision grade, C0/C3/C4 clearance, stainless‑steel variant, OEM outer‑ring laser marking, neutral export anti‑rust carton, special‑temperature grease filling.

4. Application Scenarios

6311‑ZZ double‑shield deep‑groove ball bearing is maintenance‑free rotary support spare‑part for 55 mm‑shaft machinery under dry‑dust operating environment:

• Medium‑large industrial three‑phase motors, generator rotors, centrifugal‑fan main‑shaft bearing assemblies
• Water‑pump & hydraulic‑pump transmission rotating units
• Reducer input/output shaft bearing positions
• Logistics heavy‑conveyor idle rollers, textile‑machine large‑roller transmission bearings
• General‑purpose agricultural machinery, packaging‑equipment rotating support positions

Aftermarket interchangeable 6300‑series ZZ shielded deep‑groove ball bearing
Low‑noise dust‑proof bearing solution for medium‑large motor manufacturers, fan/pump OEMs and industrial‑equipment bulk‑maintenance procurement.

5. Why Choose GQZ Bearing

• 25‑years manufacturing experience of 6300‑series deep‑groove ball bearings including 6311‑ZZ.
• 6311‑ZZ is dimension‑for‑dimension interchangeable with international‑standard counterparts, consistent load‑rating and ZZ‑shield sealing dimensional tolerances.
• Complete OEM & ODM custom service covering multi‑precision‑grade, multi‑clearance‑group, stainless‑steel material and special‑temperature‑resistant grease filling.
• Strict pre‑shipment QC: GCr15 raw‑material metallurgy & hardness inspection, steel‑ball sorting, long‑cycle high‑speed rotation aging test, dry‑dust environment wear‑simulation test.
• Professional bearing engineering team provides one‑on‑one load‑matching calculation, shaft‑housing fit‑tolerance guidance within 24 working hours.
• Large‑scale production workshop offers competitive factory‑direct bulk‑wholesale price, stable long‑term supply for global medium‑large‑motor, fan, pump and general‑machinery spare‑part buyers.
• We focus on ZZ metal‑shield maintenance‑free deep‑groove ball‑bearings, ISO‑standard metric dimensions, pursuing win‑win long‑term cooperation with general‑industrial‑transmission‑equipment suppliers.

6. Quality Control

• Raw‑material chemical‑composition, internal‑defect and hardness inspection for GCr15 inner‑ring, outer‑ring and steel‑ball blanks
• Precision turning, multi‑time stress‑relief tempering, ultra‑precision super‑finish grinding for deep raceway surface
• Steel‑ball high‑temperature quenching, mirror‑polishing and high‑precision auto‑sorting production‑line
• Stamped‑steel‑cage stamping‑riveting, ZZ metal‑shield press‑fitting, factory pre‑filled anti‑wear‑grease processing
• Targeted performance‑tests: 6311‑ZZ long‑cycle high‑speed temperature‑rise rotation aging test, dry‑dust sealing‑durability test, variable‑load anti‑fatigue wear‑detection
• Full re‑check for dimension‑tolerance, raceway surface‑finish and shielding tightness before anti‑rust‑oil coating and export moisture‑proof‑carton packing.

Each production batch of 6311‑ZZ undergoes motor‑simulation cyclic‑rotation test to guarantee stable low‑noise dust‑proof rotary‑support performance for 55‑mm‑shaft industrial‑transmission‑systems.

7. Get A Quote Now

If you need 6311‑ZZ 55x120x29 double‑metal‑shield deep‑groove ball bearings for medium‑large motor/fan manufacturing, transmission‑shaft‑assembly and industrial‑equipment‑maintenance bulk‑matching, send your purchase‑inquiry directly.
Full professional supporting‑services after inquiry submission:

• Official formal quotation reply within 24 working‑hours
• One‑on‑one radial‑&‑axial‑load‑matching calculation, shaft‑housing‑fit‑tolerance guidance from professional‑bearing‑engineers
• Custom‑bearing‑performance‑upgrade options including multi‑precision‑grade, multi‑clearance‑group and special‑temperature‑resistant‑grease
• Favorable factory‑direct bulk‑wholesale price for large‑volume 6311‑ZZ single‑model‑orders

Please provide purchase‑quantity, working‑conditions (high‑speed / dry‑dust / vibration) and continuous‑operating‑temperature to get detailed official‑quotation‑documents.

8. FAQ