What is a crossed roller bearing?

What is a crossed roller bearing?

A crossed roller bearing is a high-precision rotary bearing featuring cylindrical rollers arranged in a 90° V-groove pattern. By alternating the orientation of each roller perpendicular to the next, this single-row design can simultaneously handle radial, axial, and moment (tilting) loads. It is a compact, highly rigid alternative to traditional double-row bearing setups.

Features of crossed roller bearing

High Rigidity: Cylindrical rollers provide line contact rather than point contact, resulting in 3 to 4 times the stiffness of ball bearings.

Compact Design: The slim profile allows for significant space savings and reduced machine weight.

High Rotation Accuracy: Precision manufacturing minimizes runout, ensuring micron-level stability during operation.

Integrated Loading: A single unit manages multi-directional forces, simplifying the overall mechanical structure.

Types of crossed roller bearings

Standard Type: Utilizes split rings (inner or outer) held by retaining rings; ideal for general high-precision rotation.

High Rigidity (Solid) Type: Features one-piece, non-split inner and outer rings for maximum stiffness and high-speed stability.

Mounting Hole Type: Comes with pre-drilled bolt holes, allowing for direct installation without the need for a housing or presser flange.

Slim Type: Optimized with an extremely thin cross-section for applications with severe height or width limitations.

Applications of the crossed roller bearing

Robotics: Primarily used in the rotating joints of industrial, medical, and humanoid robots.

Machine Tools: Critical for CNC rotary tables, indexing heads, and grinding machine spindles.

Medical Equipment: Found in high-precision imaging systems like CT scanners and X-ray bases.

Precision Instruments: Used in semiconductor manufacturing equipment and high-accuracy optical measurement tools.

How does a crossed roller bearing work?

The bearing works by distributing load across rollers placed in a 90° V-shaped raceway. As the rings rotate, the alternating rollers share the stress from various angles—some handle axial thrust while others manage radial pressure. Internal spacers prevent rollers from contacting each other, which reduces friction and ensures a consistent, smooth rotational torque even under high-load conditions.

How to install crossed roller bearing

Preparation: Thoroughly clean the shaft and housing, ensuring all burrs and dust are removed.

Seating: Insert the bearing while keeping it perfectly horizontal. Use a plastic hammer to tap the perimeter lightly until it is fully seated.

Alignment: Position the fixing flange and align the screw holes with the bearing rings.

Bolting: Tighten the mounting bolts in a diagonal (cross) pattern in several stages to ensure even pressure and prevent ring distortion.