HMK no outer ring double row full complement cylindrical roller bearings are professional cage-free heavy-duty radial bearings, divided into three mainstream industrial series: F standard series, RSL widened heavy-duty series, CPM precision gearbox series. 

All three series adopt double row full complement roller design without retainer cage and independent outer ring. The equipment shaft directly serves as the outer raceway, realizing ultra-large contact area and far higher radial load capacity than conventional caged bearings. The integrated compact structure saves housing design space and reduces mechanical processing costs, specially optimized for low-speed, intermittent heavy pressure industrial working conditions.

1. F Series — Standard Universal No Outer Ring Bearings

F series is the most widely used general model for lifting, textile and ordinary reducer equipment. Balanced load capacity and size, complete metric standard sizes (F20xx, F25xx, F30xx), stable performance and large inventory volume.

2. RSL Series — Widened Super Heavy Load Bearings

RSL series is an upgraded widened version based on F series, with thicker roller rows and enhanced inner ring structure. It is designed for metallurgical roller tables, heavy conveyor tracks and continuous heavy-load mechanical equipment, providing stronger rigidity and anti-deformation ability.

3. CPM Series — Precision Gearbox Dedicated Bearings

CPM series is European standard precision no outer ring full complement bearing, featuring high precision tolerance, uniform stress and compact cross-section. It is the core internal bearing for planetary reducers, walking gearboxes and imported mechanical replacement parts. 

All HMK three-series full complement bearings adopt overall quenched GCr15 bearing steel and ultra-precision raceway grinding technology. Cage-free dense roller layout ensures ultra-high rigidity and fatigue resistance under long-term heavy load. We support full standard size supply and non-standard drawing customization.

Core Advantages Of No Outer Ring Full Complement Cylindrical Roller Bearings 

1. Three Complete Series For All Working Conditions

F standard type, RSL widened heavy-duty type, CPM precision gearbox type, fully cover universal, heavy-load and high-precision industrial scenarios.

2. Ultra-High Double Row Full Roller Load Capacity

Cage-free double row dense rollers maximize contact area, radial load capacity 2~3 times higher than ordinary cylindrical roller bearings.

3. No Outer Ring Compact Structure

Shaft surface replaces outer ring raceway, greatly reduce installation space and save housing processing cost.

4. Enhanced Rigidity & Anti-Deformation Performance

Dense roller arrangement effectively disperses heavy pressure, no obvious deformation under long-term static load and impact load.

5. Precision Tolerance & Stable Operation

High-precision grinding process ensures low vibration, high stability and long service life for reducer and metallurgical equipment.

6. Easy Assembly & Low Maintenance

Separable inner ring and roller assembly, convenient installation and replacement, suitable for various compact mechanical structures.

Material & Production Process

All inner rings and rolling rollers of HMK F, RSL and CPM no outer ring double row full complement bearings are manufactured from premium GCr15 chrome bearing steel. 

F series uses standard forged GCr15 for general working conditions; 

RSL widened heavy-duty bearings adopt thickened forged blanks with secondary stabilization tempering to withstand steel mill impact and high radiant heat; 

CPM precision gearbox series apply vacuum degassed refined GCr15 for minimal dimensional deviation. 

Every component goes through complete precision processing including forging, CNC semi-finish turning, integral quenching & tempering, multi-pass super precision raceway grinding and dust-free assembly. The rolling contact surface reaches mirror grinding finish with ultra-low roughness, while CPM models add extra raceway lapping for higher running stability. 

Optional surface treatments are available: phosphating for moisture anti-rust, shot peening for RSL heavy impact resistance and manganese phosphate coating for CPM easy assembly. The whole bearing maintains high hardness HRC60–64 after heat treatment, greatly extending service life under continuous low-speed ultra-heavy radial load.

Main Applications

• Lifting Machinery: Crane wire rope sheave, winch pulley, lifting spindle assembly

• Industrial Reducers: Planetary gearbox, heavy vertical reducer, walking machinery gearbox

• Metallurgical Equipment: Steel mill roller table, continuous conveying heavy roller

• Textile Machinery: Heavy loom transmission roller, textile tension roller assembly

• Construction Machinery: Guide roller, engineering machinery heavy load walking wheel

• Imported Equipment Maintenance: European machinery CPM model replacement bearings

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