Product Overview

The 222 series Spherical Roller Bearings are double-row, self-aligning bearings featuring barrel-shaped rollers. They utilize an outer ring with a spherical raceway and two rows of symmetrical barrel-shaped rollers, offering excellent self-aligning capabilities. They accommodate shaft-to-housing misalignment angles of 1°–2.5° and compensate for shaft deflection and coaxiality errors during installation. Designed primarily for heavy radial loads, they also support moderate bidirectional axial loads and exhibit outstanding shock and vibration resistance; however, they are unsuitable for applications involving purely axial loads. As a medium-width series, they offer greater width and higher load-carrying capacity than the 213 series, making them a mainstay bearing type in heavy industry. They are available with either cylindrical bores or 1:12 tapered bores. The outer ring can be specified with a W33 lubrication groove and oil holes to facilitate periodic relubrication, and they are commonly produced in P0 or P6 precision classes.

Materials and Model Suffix Explanations

1. Core Materials

Inner ring, outer ring, and rolling elements: **High-carbon chromium bearing steel (GCr15)**, produced via vacuum degassing and subjected to quenching and tempering; surface hardness is HRC 58–62, offering high resistance to contact fatigue and wear.

Cage: CA machined brass cage (preferred for heavy-load and high-vibration applications); CC pressed steel cage (lightweight, suitable for general-purpose mass applications); E-type (optimized internal structure with reinforced roller design for increased load ratings).

2. Common Suffix Definitions

- CA: Machined brass cage; CC: Pressed steel cage; E: Reinforced internal structure

- K: 1:12 tapered bore; W33: Outer ring with lubrication groove and three oil holes

- C0/C2/C3/C4: Radial internal clearance classes; C3 (larger clearance) is preferred for vibrating equipment.

Example: 22220CA/W33C3 – 222 series, brass cage, outer ring lubrication groove, C3 large clearance.

Specifications

The series covers inner diameters ranging from 40 mm to 320 mm (model numbers 22208–22264). Key parameters include inner diameter (d), outer diameter (D), width (B), basic dynamic load rating (Cr), static load rating (Cor), and limiting speeds for grease and oil lubrication.

Example: 22220CA/W33 — Inner diameter 100 mm, outer diameter 180 mm, width 46 mm; dynamic load 335 kN, static load 424 kN; grease lubrication limit 2,800 r/min, oil lubrication limit 3,400 r/min.

Note: Tapered bore (K-type) models require adapter sleeves or withdrawal sleeves for shaft mounting.

Manufacturing Process

1. Raw Material Inspection: Spectroscopic analysis and flaw detection of steel to eliminate defects such as cracks and inclusions.

2. Forging: Hot forging of rings to ensure a dense microstructure; cold heading of rollers.

3. Heat Treatment: Through-hardening followed by low-temperature tempering; strict control of deformation to meet hardness and residual austenite specifications.

4. Turning: Rough and finish turning of ring datum surfaces and raceways, leaving grinding allowance.

5. Grinding: Super-finishing of raceways to reduce surface roughness and enhance fatigue life; finish grinding and super-finishing of rollers.

6. Assembly and Sorting: Internal clearance grouping, matching of rollers and rings, and cage press-fitting; machining of oil grooves and holes in the outer ring for W33 models.

7. Cleaning, Anti-rust Treatment, and Warehousing: Full inspection of dimensions, clearance, vibration, and noise; vacuum anti-rust packaging. 

Application Scenarios

Widely used in heavy-duty equipment subject to vibration, shock, shaft deflection, or misalignment during installation:

- Mining: Vibrating screens, crushers, conveyor pulleys;

- Metallurgy: Rolling mill auxiliary rolls, continuous casting equipment;

- Building Materials: Ball mills, rotary kilns, industrial fans;

- Paper making, cement, construction machinery, and conveying equipment.

Tapered bore versions are suitable for long shafts or drive systems requiring on-site preload adjustment; W33 versions (with lubrication groove) are suitable for equipment requiring grease replenishment without stopping operations.

Installation Guidelines

1. Distinguish between cylindrical and tapered bores: Cylindrical bore bearings should preferably be installed using the thermal method (heating temperature ≤120°C; direct heating with an open flame is prohibited). Tapered bore bearings require adapter sleeves or withdrawal sleeves; tighten gradually while controlling the reduction in radial clearance.

2. Never strike the rolling elements or the cage directly; impact force must only be applied to the end faces of the bearing rings.

3. Strictly adhere to the catalog specifications for housing and shaft fits; select a tighter fit for heavy-duty or shock-prone conditions. C3 clearance is preferred for vibrating equipment.

4. Rotate the shaft manually after assembly; rotation should be smooth and free of binding or jamming. Do not force the assembly to lock up.

5. Align the W33 lubrication groove with the lubrication port on the bearing housing to ensure an unobstructed lubrication path.

Maintenance and Care

1. Lubrication: Lithium-based extreme-pressure (EP) grease is preferred; use oil lubrication for high-speed applications. Replenish grease regularly, ensuring old grease is fully purged from the seal area to prevent overheating caused by excessive grease.

2. Operational Monitoring: Monitor bearing temperature, vibration, and noise. Under normal operation, the temperature rise should not exceed the ambient temperature by more than 40°C. Shut down and inspect immediately if abnormal noise occurs or if the temperature rises sharply.

3. Storage: Protect against moisture and rust; store flat. Do not hang vertically for extended periods to avoid plastic deformation of the bearing rings. 4. Failure Analysis: Flaking and pitting are typically caused by overloading or insufficient lubrication; cage damage usually stems from impact or improper installation; abnormal clearance requires checking for wear on the shaft and housing bore.

Selection Considerations

This series has a lower speed limit than cylindrical Roller Bearings and is unsuitable for extremely high-speed applications. If the axial load component is excessive, a thrust bearing should be used to handle the axial force. In harsh operating environments involving moisture or dust, additional external sealing is recommended to extend service life.