1 Complete Model & Code Explanation

Model: S71901 CD/HCP4A

Code Definition

S: Stainless Steel, martensitic stainless steel material with basic anti-rust and condensation resistance

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 loads with prominent axial thrust

No seal suffix: Open non-sealed structure, no pre-filled grease from factory, continuous external circulating oil lubrication is required

HCP4A: Upgraded ISO P4A ultra-high precision grade, outstanding 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: This open stainless steel single bearing only provides basic rust resistance suitable for slightly humid and condensation conditions. Long-term immersion in aqueous solution, acid and alkali corrosive media is prohibited. Open design offers no dust protection; complete housing sealing is necessary on equipment. Long-term high-speed operation relying solely on one-time grease filling is not recommended; oil-air or oil mist continuous lubrication is preferred. Stainless steel version delivers lower load rating than bearing steel 71901 CDGA/HCP4A. Bearing steel variant should be selected under heavy load conditions.

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: Open type, no seal

Base material: Martensitic stainless steel

Surface coating: Uncoated

Pre-installed lubricant: No pre-filled 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: HCP4A (upgraded ISO P4A ultra-high precision grade)

Basic dynamic load rating: 2.36 kN

Basic static load rating: 1.08 kN

Speed reference: Contact manufacturer for attainable rotational speed data

Net weight: 0.0102 kg

Indicative carbon footprint: 0.037 kg CO₂e

eClass code: 23-05-08-04

UNSPSC code: 31171531

Suffix Comparison within Series

S71901 CD/HCP4A: Stainless steel, 30° contact angle, open non-sealed, no pre-filled grease, HCP4A super precision, duplex capable (this model)

S71901 CDB/HCP4A: Stainless steel double-sided non-contact sealed bearing with 30° contact angle

S71901 ACD/HCP4A: Stainless steel open high-speed bearing with 25° contact angle

S71901 CDQ/HCP4A: Stainless steel factory pre-matched duplex open bearing set

71901 CDGA/HCP4A: Bearing steel open bearing with 30° contact angle, higher load capacity, no anti-rust property

2 Structure & Operating Characteristics

Japan NMT S71901 CD/HCP4A adopts the compact 719 extra-light structure. The CD 30° contact angle raceway design balances radial and axial load capacity and delivers good axial rigidity for various precision high-speed rotary shafts. Inner and outer rings are manufactured from martensitic stainless steel. Compared with conventional bearing steel, it can resist condensation and slightly humid air inside clean workshops and greatly reduce rust risk during shutdown standby.

The open non-sealed structure eliminates friction loss and airflow disturbance generated by sealing components, achieving higher limiting speed than sealed stainless steel bearings of equal size. No lubricant is pre-filled at delivery, compatible with mainstream industrial continuous external lubrication modes including oil-air, oil mist and low-pressure oil injection. It avoids grease dilution and washing-out caused by circulating lubricant and suits long continuous high-speed operation.

Bearings are supplied as individual units without factory duplex grinding. Users can flexibly configure various duplex layouts with spacers according to equipment requirements. Stainless steel material has slightly lower hardness than bearing steel and reduced load rating, making it ideal for medium & light load precision rotary applications. Bearing steel version shall be chosen under continuous heavy shock load.

3 Core Performance Advantages

1. S stainless steel substrate: Basic rust resistance to cope with condensation and mild humidity in clean workshops and lower failure risk caused by corrosion.

2. CD 30° contact angle geometry: Superior axial load capacity for combined radial and axial loads dominated by axial thrust.

4. Open non-sealed construction: Removes sealing friction loss to raise limiting speed, compatible with multiple external circulating lubrication systems.

4. HCP4A ultra-high precision grade: Upgraded P4A tolerance with small rotary runout, satisfying high-precision positioning requirements of optical and semiconductor equipment.

5. Flexible free duplex assembly: Single bearing supports DB/DF/DT layouts to match different spindle rigidity designs.

6. Ultra-precision mirror raceway grinding: Reduces vibration and noise during high-speed rotation and improves rotary stability.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

Assembly of HCP4A ultra-precision stainless steel bearings is recommended in constant-temperature dust-free clean zones. Thermal mounting is preferred; direct striking on rings and raceways is forbidden. Raceways of open bearings lack protection; avoid direct bare-hand contact to reduce surface contamination risk. When two bearings work as a set, high-precision spacers are required and target preload shall be adjusted via load measurement to ensure uniform load distribution and prevent high-speed abnormal vibration.

5.2 Duplex Layout & Selection Guidance

Supply condition: Independent open single bearing

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

Selection reference:

Slightly humid cleanroom with condensation risk, external oil-air lubrication, medium-light load → S71901 CD/HCP4A (this model);

Same corrosive environment, no external oil supply available, long-term grease service needed → S71901 CDB/HCP4A;

Predominantly radial load, higher limiting speed required → S71901 ACD/HCP4A;

Mass standardized equipment without on-site preload adjustment → S71901 CDQ/HCP4A;

Dry clean environment, heavy load, no anti-corrosion demand → bearing steel 71901 CDGA/HCP4A.

5.3 Lubrication Scheme

S71901 CD/HCP4A features open construction without factory pre-filled grease. Continuous external oil supply system is mandatory. Oil-air lubrication, oil mist lubrication and low-pressure injection cooling lubrication are recommended. Long-term high-speed operation relying only on one-time grease filling is prohibited. Select high-speed spindle lubricating oil suitable for stainless steel, filter oil regularly to prevent hard particles from scratching mirror-finished raceways.

5.4 Environmental Application Notes

Stainless steel material only offers basic rust protection, not resistant to salt water, acid-alkali mist or continuous immersion. Open design has no dust-proof function; complete dust sealing must be installed on equipment housing. Dust invading raceways will trigger abrasive wear and shorten service life significantly. Shut down immediately once lubrication supply fails to avoid surface scuffing due to dry friction.

6 Daily Maintenance & Fault Troubleshooting

Carry out low-speed staged running-in after assembly, continuously monitor vibration and temperature, and increase rotational speed step by step after stable operation. Maintain stable oil supply of external lubrication system and clean oil filters periodically.

Although stainless steel resists rust better, pitting corrosion may still occur under long standby and high humidity. Intermittent oil supply or dry sealed storage is recommended for long shutdown periods. Stainless steel has relatively low hardness; overload and shock loads must be avoided.

Typical failure causes: raceway scratch induced by foreign particles, dry friction seizure after lubrication interruption, continuous overheating caused by improper preload, uneven load sharing due to low-precision spacers, surface pitting under prolonged high humidity.

Formulate regular inspection plans to monitor rotary accuracy, abnormal noise and temperature rise, so as to prevent accuracy drift, excessive vibration and bearing seizure in advance.