1 Complete Model & Code Explanation

Model: D/W R144 R

Code Definition

D/W: Imperial R-series miniature bearing identifier

R144: Base imperial dimension; bore 1/4", outer diameter 1/2"

R: Wide variant, width upgraded to 1/4" (standard R144 width 3/16")

Structure: Open type, no shields, no rubber seals

Supply form: Single independent bearing, no factory duplex grinding, DB/DF duplex arrangement not supported

Important reminder: D/W R144 R is an open-type widened imperial stainless steel miniature bearing supporting radial loads and moderate bidirectional axial loads. Without any external sealing structure, it provides no protection against dust, moisture or liquid ingress and is only recommended for clean, dry, dust-free enclosed housings. No grease pre-filled at factory; lubricant oil or grease shall be applied on-site during assembly. The widened design improves load capacity while limiting speed is slightly lower than standard-width R144. Exposure to dusty surroundings will rapidly trigger abrasive raceway wear; external uncovered installation is prohibited.

Basic Parameters

Bore d: 1/4" (6.35 mm)

Outer diameter D: 1/2" (12.70 mm)

Width B: 1/4" (6.35 mm)

Bearing type: Single-row deep groove ball bearing

Number of rows: Single row

Bore form: Straight cylindrical bore

Seal arrangement: Open type, no shields & no seals

Oil groove: Without oil groove

Outer ring locating feature: No locating groove or shoulder

Cage: Stamped stainless steel cage

Radial internal clearance: CN standard clearance

Material: Stainless steel

Surface coating: Uncoated

Pre-installed lubricant: None (factory unfilled)

Relubrication capability: On-site lubrication filling supported

Duplex arrangement: Not supported, single unit operation only

Basic dynamic load rating: 0.232 kN

Basic static load rating: 0.112 kN

Reference speed: 106 000 r/min

Limiting speed: 69 000 r/min

Net weight: 0.00044 kg

Indicative carbon footprint: 0.00078 kg CO₂e

eClass code: 23-05-08-01

UNSPSC code: 31171504

Series Suffix Comparison

R144: Standard width 3/16", open type, higher rotational speed, lower load rating

R144 R: Wide width 1/4" (this model), improved load capacity, slightly reduced limiting speed

R144 R-Z: Wide version with single metal shield

R144 R-2Z: Wide version with double metal shields

R144 R-2RS: Wide version with double rubber seals, dust & moisture resistant, further speed reduction

Steel R144R: Bearing steel wide imperial bearing, similar load capacity, no anti-rust property

2 Structure & Operating Characteristics

Japan NMT D/W R144 R is widened open-type stainless steel miniature deep groove ball bearing from imperial R series. Based on standard R144, bearing width is increased, designed for compact high-speed rotary mechanisms using imperial shafts with restricted radial installation space but higher load demand. Fully stainless steel construction delivers basic anti-corrosion advantage over bearing steel counterparts, suitable for dry clean equipment interiors with minor condensation.

Equipped with integrated stamped stainless steel cage. The widened inner space optimizes ball layout and raises load rating and impact resistance. Open construction eliminates friction loss from sealing components for low running torque. Compared with standard-width R144, longer contact line improves load capacity while rotational inertia rises moderately and limiting speed decreases slightly. Standard CN radial clearance matches common assembly tolerances of miniature imperial shafts.

The bearing mainly withstands radial loads and tolerates certain bidirectional axial loads. Without outer protection, dust and moisture directly attack rolling elements and raceways, so installation is limited inside fully sealed dust-free housings. No lubricant supplied from factory; users can select oil or grease during assembly according to speed and load conditions.

3 Core Performance Advantages

1. Widened imperial dimension: 1/4"×1/2"×1/4", higher load capacity than standard R144 under identical bore and outer diameter.

2. Stainless steel construction: Inherent basic rust resistance, applicable to slight condensation inside clean equipment.

3. Open unsealed design: No friction loss from seals, low rotation torque and maintained high limiting speed.

4. Stamped stainless steel cage: Stable structure, suitable for high-speed operation of miniature bearings and resistant to minor shocks.

5. CN standard radial clearance: High universality, convenient for standardized selection and replacement of imperial machinery.

6. Flexible lubrication scheme: No factory pre-filled grease; lubricant can be freely selected according to working conditions.

7. Widened raceway structure, balancing high speed and medium load for continuously loaded compact mechanisms.

4 Typical Application Fields

4.1 Spare Parts & Matching for Imperial Equipment

Spare components of imported precision instruments, overseas-standard automation transmission parts, upgrade replacement parts for imperial shaft machinery.

4.2 High-Speed Medium-Load Drive Units

Small high-speed motors, industrial model transmission spindles, handheld precision rotary tools.

4.3 High-End Optical Inspection Instruments

Laboratory optical equipment, precision lens adjustment assemblies, rotary actuators for image sensors.

4.4 Enclosed Automated Test Modules

Fully sealed dust-free automated actuators, compact laboratory test fixtures, inner rotary shafts of precision detection equipment.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

Assembly must be carried out on clean workbenches to prevent dust and fiber contaminants entering raceways. Never strike bearing end faces directly. Use dedicated press-fitting tooling for uniform loading to avoid ring tilting and collision damage to balls. Strictly control interference fit between shaft and housing. Excessive interference reduces internal clearance and causes temperature rise at high speed. Secure bearings during assembly due to tiny dimension to avoid loss.

5.2 Selection Guidance

Sealed dust-free housing, maximum speed priority with light load → D/W R144 standard width

Sealed dust-free housing, higher load required within identical installation space → D/W R144 R open wide type (this model)

Dry dust exposure, balance protection and rotational speed → R144 R-Z / R144 R-2Z wide shielded models

Exposed to dust, moisture and liquid splashes requiring sealing protection → R144 R-2RS wide sealed model

Dry indoor environment without anti-rust demand, cost control prioritized → bearing steel R144R wide version

5.3 Lubrication Instruction

No lubricant pre-filled inside bearing. Select special miniature bearing oil or grease during assembly according to rotational speed, temperature and load. Lubricant easily escapes in open configuration; periodic re-lubrication passages are recommended for equipment running continuously long hours. Long-term operation in dusty or high-humidity environments without housing shielding is forbidden. Wear accelerates rapidly once lubrication fails.

5.4 Environmental Application Notes

The open structure provides no dust, moisture or liquid resistance. Direct exposure to dust, water mist and oil contamination is prohibited. Stainless steel only delivers basic rust resistance; slow surface oxidation occurs under persistent high humidity even without dust. A sealed outer housing is mandatory to isolate external media.

6 Daily Maintenance & Fault Troubleshooting

Carry out short low-speed running-in after assembly and lubrication filling. Gradually increase speed to rated level only after confirming no abnormal noise or temperature rise. Typical faults of open wide bearings: continuous noise growth, increased rotation resistance, excessive radial and axial clearance.

Common failure causes: abrasive wear from dust ingress, depletion of lubricant, insufficient clearance caused by improper assembly tolerance, sustained excessive axial load. Wear on raceways and balls cannot be repaired; replacement with new bearing is recommended upon failure.