Spherical Roller Bearings

213 Series Double Row Spherical Roller Bearings

The 213 series double row spherical roller bearings feature a medium-width internal structure with compact overall dimensional specifications. With a moderate cross-section design, this range perfectly balances load-carrying capacity and installation space, positioning it as a universal intermediate specification between lightweight narrow series and heavy extra-wide series. Its reliable self-aligning performance effectively compensates for minor shaft misalignment and deflection, maintaining stable rotational precision during continuous cyclic operation.

Available with full standard cage configurations including CC stamped steel, E enhanced internal geometry, and solid brass CA & MB variants, these bearings flexibly adapt to diverse operating speed and lubrication conditions. They steadily withstand heavy radial loads and moderate bidirectional axial loads, delivering consistent and durable performance for long-term cyclic industrial operation.

Versatile and well-balanced in structure and performance, the 213 series is widely applied in general medium-duty mechanical equipment. Typical scenarios include small vibrating screens, light crushing machinery, medium-sized conveyor systems and general industrial gearbox units.

Size range: Inner Diameter: 50-230 mm

Material: GCr15/GCr15SiMn/G20Cr2Ni4A

Load Capacity: High radial and axial load capacity

Cage Types: CC / E /CA / MB / others

1. What are 213 Series Spherical Roller Bearings

The 213 series are standard medium-size narrow-section double-row spherical roller bearings, consisting of a spherical outer ring, two rows of barrel-shaped rollers, an inner ring and a cage. The outer ring features a spherical raceway enabling self-aligning capability. These bearings can withstand heavy radial loads as well as moderate bidirectional axial loads, serving as compact general-purpose heavy-duty spherical roller bearings.

2. Designation System of 213 Series Spherical Roller Bearings

Take model 21314CAK/W33 as an example for breakdown:

213: Series code. Digit 2 denotes double-row rollers; 13 stands for the basic medium narrow-section spherical roller bearing series.
14: Bore code, corresponding to a bearing bore diameter of 70 mm.
CA: Machined brass cage; CC: Stamped steel cage; E: Reinforced rollers for increased load capacity.
K: 1:12 tapered bore, for mounting with an adapter sleeve.
W33: Outer ring with lubrication groove and grease fitting hole; C3/C4 represent increased internal clearance.

3. Characteristics of 213 Spherical Roller Bearings

Built-in self-aligning function, compensating for shaft misalignment and shaft deflection up to approximately 0.5°.
Moderate cross-sectional width with compact structure, requiring minimal installation space.
Double-row barrel-shaped rollers deliver excellent shock resistance and superior radial load capacity.
Available with cylindrical bore and tapered bore to suit various mounting configurations.
Optional outer ring lubrication groove and hole allow relubrication without equipment shutdown.

4. Applications of 213 Spherical Roller Bearings

Small mine crushers, fan main shafts, conveyor pulleys, medium & small reducers, heavy-duty woodworking machine tools, agricultural harvesters, standard vibrating screens.

**213 Series Double Row Spherical Roller Bearings**
Series	Bearing Models	d (mm)	D (mm)	T (mm)	Approx Weight (KGS)
21304	21304 CC / 21304E / 21304CA / 21304MB	20	52	15	0.16
21305	21305 CC / 21305E / 21305CA / 21305MB	25	62	17	0.254
21306	21306 CC / 21306E / 21306CA / 21306MB	30	72	19	0.41
21307	21307 CC / 21307E / 21307CA / 21307MB	35	80	21	0.54
21308	21308 CC / 21308E / 21308CA / 21308MB	40	90	23	0.74
21309	21309 CC / 21309E / 21309CA / 21309MB	45	100	25	0.98
21310	21310 CC / 21310E / 21310CA / 21310MB	50	110	27	1.32
21311	21311 CC / 21311E / 21311CA / 21311MB	55	120	29	1.7
21312	21312 CC / 21312E / 21312CA / 21312MB	60	130	31	2.05
21313	21313 CC / 21313E / 21313CA / 21313MB	65	140	33	2.5
21314	21314 CC / 21314E / 21314CA / 21314MB	70	150	35	3.15
21315	21315 CC / 21315E / 21315CA / 21315MB	75	160	37	3.8
21316	21316 CC / 21316E / 21316CA / 21316MB	80	170	39	4.54
21317	21317 CC / 21317E / 21317CA / 21317MB	85	180	41	5.36
21318	21318 CC / 21318E / 21318CA / 21318MB	90	190	43	5.98
21319	21319 CC / 21319E / 21319CA / 21319MB	95	200	45	6.5
21320	21320 CC / 21320E / 21320CA / 21320MB	100	215	47	8
21322	21322 CC / 21322E / 21322CA / 21322MB	110	230	50	10.7

Production Process

Blueprint · Designing Precision

Given the structural characteristics of crossed roller bearings (rollers arranged in a 90° cross pattern), our technical team uses 3D CAD and finite element analysis (FEA) software to accurately calculate raceway angles, spacing, and interference.

Customizing products based on customer operating conditions, we benchmark against P2/P4/P5 tolerance classes and simulate post-assembly rotational precision in advance. The blueprint serves as the sole standard guiding all subsequent turning, grinding, and inspection processes.

Turning & Grinding · Rough to Mirror

Turning and grinding are the core processes that determine the bearing's geometric precision. We use high-rigidity CNC lathes for step-by-step ring processing, ensuring basic inner/outer diameter and raceway dimensions through rough, semi-finish, and finish turning while leaving grinding allowances.

We employ plunge grinding with formed grinding wheels for the V-shaped raceways of crossed roller bearings, and perform combination matching for the split inner/outer rings to ensure rotational plane runout meets P5 or higher standards.

Assembly · Interlocking Precision

The assembly of crossed roller bearings is more delicate than standard bearings: rollers must be arranged in an alternating cross pattern and precisely guided by spacers or cages.

All components are ultrasonically cleaned, dried, and grouped according to measured dimensions. High rigidity and stable torque are then imparted to the crossed roller bearings through negative clearance or preload adjustments. Assembly is completed in a constant temperature and humidity cleanroom to ensure P4/P2 level precision.

Inspection · Not Missing a Micron

As tolerance classes P5, P4, and P2 become progressively stricter, our inspection equipment and processes are upgraded accordingly:

We use high-precision roundness measuring instruments for dimensional tolerances, dial indicators with dedicated test mandrels for radial and axial runout, profilometers and Coordinate Measuring Machines (CMM) to verify raceway profiles and angles, and dedicated clearance and torque testers to determine clearance and starting torque.

Packaging · Anti-Rust & Protection

The packaging process is equally strict, ensuring zero loss of precision for the crossed roller bearings from the factory until pre-installation.

Eco-friendly anti-rust oil is evenly sprayed to ensure no residual particles in the inner cavity. Each bearing is vacuum-sealed in a thickened PE bag and film for water and dust protection, then boxed using wrapping tape. The outer carton is lined with high-density foam and pearl cotton to prevent transport collisions, and is marked with the model, precision grade (P5/P4/P2), and production batch number.