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Smooth Self-Aligning Ball Bearings from China Suppliers - Quality Factory Manufacturing for Reliable Performance

Self-aligning ball bearings are essential components in various mechanical systems, known for their unique double-row design. The outer ring features a spherical raceway that is concentric with the bearing's center point, allowing for a remarkable self-aligning capability. The inner ring is equipped with two rows of raceways, enabling the balls, cage, and inner ring to tilt freely to a limited extent during operation. This feature compensates automatically for misalignment due to shaft deflection or inaccuracies in machining and installation of the shaft and housing. It is important to note that the maximum allowable tilt between the inner and outer rings should not exceed 3 degrees, These bearings are specifically engineered to handle radial loads effectively and can accommodate minor axial loads as well. However, they are not designed to bear pure axial loads. As a trusted manufacturer in China, we take pride in providing top-quality self-aligning ball bearings suitable for a variety of applications. Partner with leading suppliers and factories to ensure you receive only the best products for your mechanical needs

Product Details

Self-Aligning Ball Bearings: Two Main Types

Basic Design Bearings
Bearings with Rubber Seals on Both Sides

Basic Design

⚙️

The basic design bearings are available with either cylindrical bore or tapered bore (taper ratio 1:12). Self-aligning ball bearings with a tapered bore can be directly mounted on tapered shaft diameters using a locking nut. Alternatively, they can be easily installed on cylindrical shafts using appropriate adapter sleeves or withdrawal sleeves. The radial clearance of the bearing can also be adjusted using an adapter sleeve.

💡 The internal design of the basic self-aligning ball bearings has been improved, providing higher load-carrying capacity compared to the original standard design. As a result, these bearings offer broader applicability—either enabling the same-sized bearing to carry heavier loads or, under unchanged load conditions, improving operational reliability and extending service life.

Sealed Bearings

🛡️

Self-aligning ball bearings can be equipped with contact seals on both sides, such as 2RS or 2RS1 type seals. These seals are made of wear-resistant synthetic rubber reinforced with thin steel plates. The bearings are permanently lubricated and require no maintenance. They should not be heated or cleaned before installation.

Dimensions

📐

The basic dimensions of self-aligning ball bearings comply with ISO 15:1981 and are listed in the dimension tables.

Angular Misalignment

📏

Self-aligning ball bearings are designed to accommodate angular misalignment between the inner and outer rings.

⚠️ The maximum allowable angular misalignment under normal operating conditions is provided in the table below. Whether the maximum value can be utilized depends on the bearing configuration design and the type of seals used.

🔬

Tolerances: Self-aligning ball bearings are manufactured with standard (normal) tolerance grades. Precision grades such as P6 and P5 are also available. Tolerance grades can be referenced in the corresponding tables.

Radial Internal Clearance

🔩

Standard self-aligning ball bearings are supplied with normal radial internal clearance. Bearings with a tapered bore are supplied with C3 group clearance as standard.

Bearings with internal clearance greater or smaller than the standard value can be produced according to customer requirements. Radial clearance values can be found in the clearance tables.

Cages

🏆 The standard cage for self-aligning ball bearings is made of glass fiber-reinforced nylon 66. This material offers advantages such as good processability, light weight, and self-lubricating properties. It can accommodate higher operating speeds and withstand temperatures up to +120°C.

🔧

For bearings operating continuously under high temperatures or harsh conditions, stamped steel cages or machined brass cages are available. For non-standard cage requirements, please contact the technical department.

Minimum Load

⚖️

To ensure satisfactory operation of ball and roller bearings, a certain minimum load must be applied. This requirement also applies to self-aligning ball bearings. Otherwise, at high speeds, inertial forces acting on the balls and cage, along with friction from the lubricant, may adversely affect rolling behavior, causing destructive sliding between the balls and raceways.

The minimum required load can be estimated using the following formula:

F_rm = k_r · ( γ · n / 1000 )^(2/3) · d_m^3.3

Where:

F_rm — Minimum radial load (N)
k_r — Minimum load coefficient:
   = 40 for series 12 and 13 bearings
   = 45 for series 22 bearings
   = 50 for series 23 bearings
γ — Operating viscosity of the lubricant at operating temperature (mm²/s)
n — Rotational speed (r/min)
d_m — Bearing mean diameter = 0.5(d + D) (mm)

⚠️ The weight of the supported components plus external forces often exceeds the minimum load. If not, additional loads must be applied, such as increasing belt tension or using other similar methods.

Dynamic Equivalent Bearing Load

P = F_r + Y₁ · F_a (kN) when F_a / F_r ≤ e P = 0.65·F_r + Y₂ · F_a (kN) when F_a / F_r > e

Values for Y₁, Y₂, and e are listed in the bearing dimension tables.

Static Equivalent Bearing Load

P = F_r + Y₀ · F_a (kN)

The value of Y₀ is provided in the bearing dimension tables.

Frequently Asked Questions

QWhat are the two main types of self-aligning ball bearings?

Self-aligning ball bearings are available in two main types: basic design bearings (with cylindrical or tapered bore) and sealed bearings with rubber contact seals (such as 2RS or 2RS1) on both sides for maintenance-free operation.

QWhat is the difference between cylindrical bore and tapered bore self-aligning ball bearings?

Cylindrical bore bearings are mounted on standard cylindrical shafts, often using adapter or withdrawal sleeves. Tapered bore bearings (taper ratio 1:12) can be directly mounted on tapered shafts with a locking nut, or on cylindrical shafts using adapter sleeves — with the added benefit of adjustable radial clearance.

QDo sealed self-aligning ball bearings require lubrication or maintenance?

No. Sealed self-aligning ball bearings (2RS / 2RS1 type) are permanently lubricated and completely maintenance-free. They should not be heated or cleaned prior to installation, as this could damage the seals or displace the grease.

QWhat cage material is used in standard self-aligning ball bearings, and what are its advantages?

The standard cage is made of glass fiber-reinforced nylon 66, which offers light weight, good processability, and self-lubricating properties. It supports higher operating speeds and can withstand continuous temperatures up to +120°C. For high-temperature or harsh environments, stamped steel or machined brass cages are available as alternatives.

QWhy is a minimum load required for self-aligning ball bearings?

At high speeds, inertial forces on the balls and cage — combined with lubricant friction — can cause destructive sliding between the balls and raceways if the applied load is too low. A minimum radial load ensures proper rolling contact and prevents premature bearing damage. The minimum load can be calculated using the formula: F_rm = k_r · (γ · n / 1000)^(2/3) · d_m^3.3.

QWhat radial internal clearance is standard for self-aligning ball bearings with tapered bore?

Self-aligning ball bearings with a tapered bore are supplied with C3 group clearance as standard, which provides greater internal clearance than normal. Bearings with cylindrical bore use normal radial internal clearance by default. Custom clearance values — larger or smaller — can be manufactured upon request to meet specific application requirements.