1 Complete Model & Code Explanation

Model: 71901 CDGA/P4A

Code Definition

71901: Basic dimension specification of 719 extra-light single-row angular contact ball bearing

CD: Standard raceway geometry with 30° nominal contact angle, excellent axial load capacity for combined radial and axial loads

GA: Double contact rubber seal. Sealing lips fit tightly to block dust and mist with basic protection performance

P4A: Upgraded ISO P4 high precision tolerance grade, stable rotary accuracy. Single unit supports on-site DB/DF/DT free duplex assembly

Supply form: Separate single bearing without factory duplex lapping. Precision spacers are required for preload adjustment when two bearings are combined.

Important reminder: 71901 CDGA/P4A is equipped with double contact seals to resist slight dust and cutting mist, but cannot endure long-term immersion or continuous liquid spraying. Contact seals create friction loss, resulting in lower limiting speed compared with open type 71901 CD/P4A. Pre-filled high-speed grease from factory, suitable for grease lubrication. Not recommended for long-term continuous circulating oil lubrication. Bearing steel is prone to rust under high humidity and condensation.

Basic Parameters

Bore d: 12 mm

Outer diameter D: 24 mm

Width B: 6 mm

Nominal contact angle: 30°

Structure: Single-row angular contact ball bearing, supplied as single unit

Internal geometry: CD raceway with 30° contact angle

Contact type: Two-point contact

Number of rows: Single row

Ring construction: Integrated inner ring, integrated outer ring

Seal arrangement: GA double contact rubber seal

Base material: Vacuum degassed high carbon chromium bearing steel

Surface coating: Uncoated

Pre-installed lubricant: Factory pre-filled high-speed bearing grease

Duplex capability: Universal matchable single bearing, supporting DB back-to-back / DF face-to-face / DT tandem layout; preload adjusted on site

Precision class: P4A (upgraded ISO high precision grade)

Basic dynamic load rating: 2.72 kN

Basic static load rating: 1.31 kN

Speed reference: Contact manufacturer for attainable rotational speed data

Net weight: 0.0115 kg

Indicative carbon footprint: 0.036 kg CO₂e

eClass code: 23-05-08-04

UNSPSC code: 31171531

Suffix Comparison within Series

71901 CDGA/P4A: Bearing steel, 30° contact angle, double contact seal, pre-filled grease, P4A high precision, duplex capable (this model)

71901 CDGB/P4A: Bearing steel double non-contact dust seal, lower friction and higher speed, only for dry dust-free environment

71901 CD/P4A: Open non-sealed, no pre-filled grease, maximum limiting speed for forced circulating oil lubrication

71901 ACDGA/P4A: Double contact seal bearing with 25° contact angle optimized for higher rotational speed

S71901 CDGA/P4A: Martensitic stainless steel bearing with double contact seal and anti-rust property

2 Structure & Operating Characteristics

Japan NMT 71901 CDGA/P4A adopts proven ultra-thin extra-light 719 series structure. CD 30° contact angle raceway evenly bears radial load and axial thrust and provides sufficient axial rigidity for miniature precision rotary spindles. Inner and outer rings are manufactured from vacuum degassed bearing steel with stable dimensional performance after heat treatment. Raceways are ultra-precision mirror ground to suppress vibration and noise during high-speed rotation.

Equipped with GA double contact rubber seals, sealing lips closely attach to ring end faces. It delivers better protection against dust and cutting fluid mist than non-contact seals, adapting to slight liquid splash and floating dust in machining environment. High-speed grease is pre-filled at factory; continuous operation can be sustained under normal working conditions without external oil supply.

Bearings are delivered as single units without factory duplex grinding. Customers arrange various duplex layouts with precision spacers according to machine structure. Friction from contact seals brings higher temperature rise at high speed compared with open and non-contact sealed variants, so rated speed must be evaluated during selection. Seals only offer basic protection and cannot resist continuous liquid flushing or heavy dust accumulation.

3 Core Performance Advantages

1. CD 30° contact angle geometry: Outstanding axial load capacity for combined loads with obvious axial thrust.

2. GA double contact seal: Superior dust and mist resistance compared with non-contact seals, suitable for lightly polluted machining environment.

3. Factory pre-filled high-speed grease: Supports independent grease lubrication without complicated circulating oil system.

4. Premium vacuum degassed bearing steel substrate: High hardness, larger load capacity than stainless steel bearings of equal size and stable dimension.

5. P4A upgraded high precision grade: Minimal rotary runout, meeting high-precision positioning requirements of rotary shafts and small machining spindles.

6. Flexible free duplex assembly: Single bearing supports DB/DF/DT layouts for diversified spindle rigidity design.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

Assembly of P4A high precision bearings is recommended in constant-temperature dust-free clean workshops. Thermal mounting is preferred; direct impact on bearing rings, rolling elements and sealing components is strictly forbidden. Dust protection must be implemented during assembly to prevent impurities abrading sealing lips in early stage. When two bearings work as a set, select precision spacers of matching accuracy and adjust target preload via load measurement to ensure balanced load sharing, avoid high-speed vibration, abnormal temperature rise and local overheating aging of sealing lips.

5.2 Duplex Layout & Selection Guidance

Supply condition: Independent single contact sealed bearing

Available assembly layout: DB back-to-back / DF face-to-face / DT tandem

Selection reference:

Working environment with cutting mist and light dust, adopting grease lubrication → 71901 CDGA/P4A (this model);

Dry dust-free environment, higher speed priority, only basic dust prevention needed → 71901 CDGB/P4A non-contact seal version;

Fully enclosed clean housing with forced circulating oil supply, pursuing maximum limiting speed → 71901 CD/P4A open bearing;

Condensation exists and anti-rust performance required → S71901 CDGA/P4A stainless steel sealed bearing;

Predominantly radial load, higher rotational speed prioritized → 71901 ACDGA/P4A.

5.3 Lubrication Scheme

71901 CDGA/P4A comes pre-filled with high-speed grease. Long-term grease lubrication is recommended under standard conditions. Long-term high-pressure circulating oil lubrication is not advised; continuous oil flushing will wash away built-in grease and weaken long-term lubrication performance of seals.

For equipment running continuously at high speed, replenish compatible high-speed bearing grease periodically according to maintenance cycle. Monitor bearing temperature persistently. Replace with non-contact sealed or open type if temperature keeps excessively high. Do not mix greases of different brands to avoid deterioration and failure.

5.4 Environmental Application Notes

Double contact seals provide basic dustproof and splash mist resistance, but continuous liquid spraying, long-term immersion and heavy dust accumulation are prohibited. External protective covers must be added for scenarios with persistent cutting fluid flushing. Bearing steel lacks long-term anti-rust performance and easily suffers corrosion under high humidity and condensation; stainless steel sealed bearings shall be selected for such environments. Keep dry protection during long equipment shutdown to prevent seal aging and raceway rust.

6 Daily Maintenance & Fault Troubleshooting

Carry out low-speed staged running-in after assembly, continuously monitor bearing temperature and vibration, and gradually raise speed to rated value after stable operation. Focus on temperature near sealing areas; abnormal temperature rise usually indicates excessive friction of sealing lips or oversize preload.

Replenish grease regularly according to maintenance cycle to avoid dry failure of internal lubricant. Inspect seal appearance periodically. Replace bearing once leakage, hardening or cracking appears. Common failure causes: dry friction due to grease depletion, sealing lip abrasion by dust penetration, raceway rust caused by liquid infiltration, seal overheating aging triggered by excessive preload.

Set up periodic inspection plan to detect abnormal noise, rising vibration and over-temperature at early stage, preventing rapid precision loss and bearing seizure.