1 Complete Model & Code Explanation

Model: D/W R144

Code Definition

D/W: Imperial R-series miniature bearing identifier

R144: Imperial specification; bore 1/4", outer diameter 1/2", 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 is an open-type 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 and dust-free environments. No grease is pre-filled from factory; suitable lubricant oil or grease must be applied on-site according to operating conditions. Free of friction loss from sealing components, it achieves higher limiting speed than sealed variants. Heavy dust exposure will rapidly cause raceway abrasion and premature bearing failure.

Basic Parameters

Bore d: 1/4" (6.35 mm)

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

Width B: 3/16" (4.7625 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: 0.195 kN

Basic static load rating: 0.088 kN

Reference speed: 118 000 r/min

Limiting speed: 76 000 r/min

Net weight: 0.00036 kg

Indicative carbon footprint: 0.00071 kg CO₂e

eClass code: 23-05-08-01

UNSPSC code: 31171504

Series Suffix Comparison

R144: Open type without seal (this model), maximum speed, zero environmental protection

R144-Z: Single metal shield, blocks dry dust

R144-2Z: Double metal shields, dual-side dust resistance

R144-2RS: Double rubber seals, dust & moisture resistance with reduced limiting speed

Steel R144: Bearing steel imperial bearing, similar load capacity, no rust resistance

2 Structure & Operating Characteristics

Japan NMT D/W R144 belongs to R-series open-type stainless steel miniature deep groove ball bearing, developed for compact high-speed rotary mechanisms equipped with imperial standard shafts and operated under clean dust-free conditions. Fully manufactured from stainless steel, it delivers basic anti-corrosion performance compared with bearing steel imperial bearings, suited for dry clean equipment interiors with minor condensation.

Adopting integrated stamped stainless steel cage with lightweight construction and stable dynamic balance to suppress vibration and noise during high-speed rotation. The open design eliminates frictional resistance caused by metal shields or rubber seals, delivering lower rolling resistance and substantially higher limiting speed than Z-type and RS sealed alternatives. Standard CN radial clearance matches common assembly tolerances of miniature imperial shafts.

The bearing primarily sustains radial loads and withstands certain bidirectional axial loads. Without external protection, dust and moisture in ambient air directly contact rolling elements and raceways; contaminants quickly trigger abrasive wear. It shall only be installed inside fully closed clean housings. Exposed applications require shielded or sealed derivative models. No lubricant is pre-filled upon delivery; oil or grease can be applied as required during assembly.

3 Core Performance Advantages

1. Standard imperial dimension: 1/4"×1/2"×3/16", perfectly compatible with precision machinery using imperial shaft diameters.

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

3. Open unsealed design: No friction loss from seals, featuring high limiting speed and low rotational resistance.

4. Stamped stainless steel cage: Low mass, stable high-speed operation and resistance to minor shocks.

5. CN standard radial clearance: High universality for standardized design of imperial transmission assemblies.

6. Flexible lubrication solution: Unfilled at factory; users may select oil or grease based on rotating speed and temperature.

7. Combined load capacity for radial and bidirectional axial loads, matching complex force conditions of compact mechanisms.

4 Typical Application Fields

4.1 Precision Equipment with Imperial Shafting

Spare parts for compact imported instruments, imperial-size automation transmission assemblies, replacement components for overseas standard machinery.

4.2 High-Speed Miniature Drive Units

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

4.3 Optical Precision Instruments

Laboratory optical testing equipment, lens fine-adjustment assemblies, precision rotary units for image sensors.

4.4 Enclosed Cavity Automation Modules

Fully sealed dust-free automated actuators, compact test fixtures, precision laboratory auxiliary devices.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

Assembly shall be performed 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 tilting of rings and collision damage to rolling elements. Strictly control interference fit between shaft and housing. Excessive interference reduces internal clearance and risks thermal seizure at high speed. Secure bearings during assembly due to tiny dimension to avoid loss.

5.2 Selection Guidance

Fully enclosed dust-free housing, maximum limiting speed priority → D/W R144 open type (this model);

Dry dust exposure, balanced speed and protection required → R144-Z / R144-2Z shielded models;

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

Dry environment without anti-rust requirement, cost control prioritized → bearing steel R144 version.

5.3 Lubrication Instruction

No lubricant is pre-filled inside the bearing. Select proper miniature bearing oil or grease according to rotating speed, temperature and load during assembly. Lubricant tends to escape easily in open configuration; periodic re-lubrication passages should be reserved for equipment with continuous long-duration operation. Long-term operation in dusty or high-humidity environments without housing shielding is not recommended. Bearing wear accelerates sharply once lubrication fails.

5.4 Environmental Application Notes

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

6 Daily Maintenance & Fault Troubleshooting

After assembly and lubricant filling, implement short low-speed running-in. Gradually raise speed to rated value only after verifying no abnormal noise or temperature rise. Typical faults of open bearings include gradually increasing noise, higher rotating resistance and excessive clearance growth.

Common failure causes: abrasive wear induced by external dust entering raceways, depletion of lubricant, insufficient clearance caused by improper mounting, sustained overload axial force. Once wear appears on raceways and balls, repair is impossible; immediate bearing replacement is recommended.