Positioning Preload vs. Constant Pressure Preload: Which Is Right for Your Angular Contact Ball Bearings?

Precision angular contact ball bearings are widely used in high-performance machines such as CNC spindles, robotics, and automation systems. These bearings are designed to carry both radial and axial loads with high accuracy and rigidity.

One of the key factors that affect the performance of these bearings is preload — the controlled removal of internal clearance. Proper preload improves stiffness, reduces vibration, and ensures smooth, precise operation.

There are two main preload methods: Positioning Preload and Constant Pressure Preload. Each has its own benefits and is best suited for different types of applications.

1. What Is Positioning Preload?

Positioning Preload means fixing the axial position of the bearings once they are assembled. The preload stays the same during operation.

How It Works:

• Bearings are matched and assembled with tight tolerances.
• Spacers or shims are used to control the exact amount of preload.
• In some cases, a locknut or screw is adjusted while measuring the starting torque.

Advantages:

• High rigidity and precision
• Simple and cost-effective
• Stable performance in controlled environments

Best For:

• Machine tool spindles
• Precision gearboxes
• Measuring equipment
• Applications with little or predictable thermal change

2. What Is Constant Pressure Preload?

Constant Pressure Preload uses a spring (like a Belleville washer) to apply a steady force on the bearings. This keeps the preload stable, even when the position of the bearing rings changes.

How It Works:

• A spring applies constant pressure to the bearing pair.
• As the shaft or housing expands or contracts due to heat, the spring adjusts to keep the preload force consistent.

Advantages:

• Maintains preload under changing conditions
• Reduces risk of overheating or failure
• Good for high-speed and dynamic applications

Best For:

• High-speed motor spindles
• Electric motors
• Aerospace components
• Semiconductor and optical equipment

Which Method Should You Choose?

Why Choose Beining Technology?

At Beining Technology, we design and manufacture high-quality angular contact ball bearings for a wide range of industrial and high-tech applications. Our engineering team can help you choose the best preload method for your specific needs — whether it's Positioning Preload or Constant Pressure Preload.

With Beining bearings, you get:

• Reliable performance
• High precision and rigidity
• Long service life

Torque Accuracy, Spindle Stability — Trust Beining Technology for precision angular contact ball bearings built for performance.