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High-Quality Cylindrical Roller Bearings from China Suppliers and Factory - Single, Double, and Four-Row Options

Cylindrical roller bearings are essential components widely used in various industries. They are categorized into three main types: single-row, double-row, and four-row cylindrical roller bearings. As a leading supplier from China, our factory specializes in manufacturing high-quality cylindrical roller bearings designed to meet diverse operational needs. Choose our products for reliability and performance, backed by extensive industry expertise

Product Details

Single-Row Cylindrical Roller Bearings

NU-type: Flanges on both sides of the outer ring; no flanges on the inner ring.

N-type: Flanges on both sides of the inner ring; no flanges on the outer ring.

These designs allow limited bidirectional axial displacement of the shaft relative to the housing, accommodating length changes caused by thermal expansion. Thus, they are suitable as non-locating bearings.

NJ-type: Flanges on both sides of the outer ring and one flange on the inner ring.

NF-type: Flanges on both sides of the inner ring and one flange on the outer ring.

NJ and NF types provide unidirectional axial positioning of the shaft.

NUP-type: Flanges on both sides of the outer ring, one flange on the inner ring, and a loose flange on the other side — enables bidirectional axial positioning of the shaft.

High-precision single-row cylindrical roller bearings with a 1:12 tapered bore for machine tool spindles are also produced.

Double-Row Cylindrical Roller Bearings

Double-row cylindrical roller bearings are manufactured as precision-grade bearings for machine tool spindles and can also be used in other precision machinery.

NN-type: Flanges on the inner ring; no flanges on the outer ring.

NNU-type: Flanges on the outer ring; no flanges on the inner ring.

To facilitate the installation of lubrication devices, bearings with oil grooves and holes on the outer ring (suffix code W33) are primarily supplied. Products with either cylindrical or tapered bores are available based on customer requirements.

Dimensions

The basic dimensions of the bearings listed in the tables comply with ISO 15:1981.

Permitted Tilt Angle

Proper adjustment of the contact condition between the rollers and raceways not only prevents abnormal loading on the contact surfaces but also accommodates misalignment between the inner and outer rings caused by installation errors. The permitted tilt angles for cylindrical roller bearings are as follows:

Narrow-type bearings (10, 2, 3, and 4 series): 3.5 arcminutes

Wide-type bearings (22 and 23 series): 1.5 arcminutes

Larger tilt angles may be permissible depending on the load magnitude and required service life. Double-row cylindrical roller bearings do not permit any tilt angle.

Tolerances

Single-row cylindrical roller bearings are produced with tolerances up to P5 grade. Additionally, single-row and double-row cylindrical roller bearings with tapered bores for machine tool spindles are manufactured with P5 grade and higher tolerances, as well as special tolerance classes SP and UP.

Radial Internal Clearance

Standard single-row cylindrical roller bearings are supplied with basic group clearance.

Single-row bearings can also be provided with C3 group clearance; some sizes are available with C4 group clearance.

Double-row cylindrical roller bearings are supplied with C1 group clearance as standard. Cylindrical bore bearings can also be supplied with C2 or C3; tapered bore bearings can be provided with C2 group clearance.

Cages

The standard cages for single-row cylindrical roller bearings are listed in the table below. Cages for NU, NJ, NF, and NUP-type bearings are typically the same as those for N-type bearings.

Glass fiber-reinforced nylon 66 cages (suffix code TN): Suitable for operating temperatures up to +120°C.

Solid brass cages (suffix code M): Available for applications requiring continuous operation under high temperatures or harsh conditions.

Bearings with standard designs using glass fiber-reinforced nylon 66 or brass cages can also be supplied with stamped steel cages upon customer request.

Minimum Load

To prevent harmful sliding between the rollers and raceways due to centrifugal forces during high-speed operation, the minimum required load for the bearing can be estimated using the following formula:

F_r = K_r · (6 + 4 · n/n_r) · (d_m / 100)²

Where:

F_r — Minimum radial load (N)
K_r — Minimum load coefficient:
- = 100 for series 10 bearings
- = 150 for series 2, 3, and 4 bearings
- = 200 for series 22 bearings
- = 250 for series 23 bearings
n — Rotational speed (r/min)
n_r — Limiting speed for oil lubrication (r/min)
d_m — Bearing mean diameter = 0.5 × (d + D) (mm)

Dynamic and Static Equivalent Loads

Dynamic Equivalent Load — Dimension Series 2 and 3:

P = F_r + 0.3F_a when 0 ≤ F_a/F_r ≤ 0.12
P = 0.94F_r + 0.8F_a when 0.12 < F_a/F_r ≤ 0.3

Dynamic Equivalent Load — Dimension Series 22 and 23:

P = F_r + 0.2F_a when 0 ≤ F_a/F_r ≤ 0.18
P = 0.94F_r + 0.53F_a when 0.18 < F_a/F_r ≤ 0.3

Static equivalent load: P₀ = F_r (kN)

Axial Load Capacity

Cylindrical roller bearings are primarily designed to carry radial loads. However, bearings with flanged rings (e.g., NJ, NF, and NUP types) can also accommodate certain axial loads. The axial load capacity is not determined by material fatigue strength but by the load-bearing capacity of the sliding surfaces at the contact area between the rollers and flanges. This depends mainly on the lubrication condition, operating temperature, and heat dissipation capabilities of the bearing.

The allowable axial load can be calculated using the following formula:

F_ap = K₁ · C₀ · (1 − F_r / 0.8C₀) · (d · D / 1000) · (1000 / n)^0.5 · K₂

Where:

F_ap — Maximum allowable axial load (N)
C₀ — Basic static load rating (N)
F_r — Actual radial load (N)
n — Operating speed (r/min)
d — Bearing inner diameter (mm)
D — Bearing outer diameter (mm)
K₁ — Coefficient: 0.3 for oil lubrication; 0.5 for grease lubrication
K₂ — Coefficient: 0.03 for oil lubrication; 0.05 for grease lubrication

The above formula applies under normal operating conditions and is valid for constant axial loads. For temporarily applied axial loads, multiply the result by 2; for impact loads, multiply by 3.

The constant axial load F_a acting on the bearing must not exceed 1.2D² (where D is the outer diameter in mm). Occasional impact loads must not exceed 3D².

To ensure uniform flange loading and sufficient operational precision of the shaft, special attention must be paid to the axial runout of the relevant contact surfaces for cylindrical roller bearings subjected to high axial loads.

Other types of single-row cylindrical roller bearings, such as full-complement self-locking bearings, can also be produced upon customer request.

Frequently Asked Questions (FAQ)

What is the difference between NU-type and NJ-type cylindrical roller bearings?

NU-type bearings have flanges on both sides of the outer ring and no flanges on the inner ring, allowing bidirectional axial displacement — making them suitable as non-locating bearings. NJ-type bearings have flanges on both sides of the outer ring and one flange on the inner ring, enabling unidirectional axial positioning of the shaft.

What tolerance grades are available for cylindrical roller bearings?

Single-row cylindrical roller bearings are produced with tolerances up to P5 grade. For machine tool spindle applications, both single-row and double-row bearings with tapered bores are available in P5 grade and higher, as well as special tolerance classes SP and UP for demanding precision requirements.

Can cylindrical roller bearings carry axial loads?

Cylindrical roller bearings are primarily designed for radial loads. However, flanged types such as NJ, NF, and NUP can accommodate certain axial loads. The axial load capacity depends on lubrication conditions, operating temperature, and heat dissipation. Constant axial loads must not exceed 1.2D², and occasional impact loads must not exceed 3D² (where D is the outer diameter in mm).

What cage materials are available for cylindrical roller bearings?

Standard options include glass fiber-reinforced nylon 66 cages (suffix TN), suitable for temperatures up to +120°C, and solid brass cages (suffix M) for high-temperature or harsh operating environments. Stamped steel cages are also available upon customer request for both standard nylon and brass cage designs.

What is the permitted tilt angle for cylindrical roller bearings?

For narrow-type bearings (series 10, 2, 3, and 4), the permitted tilt angle is 3.5 arcminutes. For wide-type bearings (series 22 and 23), it is 1.5 arcminutes. Larger tilt angles may be permissible depending on load and service life requirements. Double-row cylindrical roller bearings do not permit any tilt angle.

Why is a minimum radial load required for cylindrical roller bearings at high speeds?

At high rotational speeds, centrifugal forces can cause harmful sliding between the rollers and raceways if the applied load is too low. A minimum radial load ensures proper rolling contact is maintained. The required minimum load can be estimated using the formula: F_r = K_r · (6 + 4·n/n_r) · (d_m/100)², where K_r depends on the bearing series.