RB 2008 Integral Inner Ring Crossed Roller Bearing

Precision Grades and Suffix Designations

1. Precision Grades: Available in P5, P4, and P2 grades. The smaller the grade number, the higher the precision.

2. Suffix Designations:

• UU: Sealed on both sides.
• C0 / C1: Radial internal clearance grades.
  
  

Product Features and Advantages

1. Structural Design

RB series crossed roller bearings use cylindrical rollers arranged alternately at 90° within V-shaped raceways. The rollers are separated by a cage or spacers to maintain proper positioning and spacing. The outer ring consists of two separate sections secured by rivets or bolts, while the inner ring features an integrated, one-piece structure.

2. Key Advantages

Multi-Directional Load Capacity: The cross-arranged rollers allow a single bearing to accommodate combined radial loads, axial loads, and moment loads. This eliminates the need for multiple bearings in many applications and supports complex loading conditions.

High Rigidity: Compared with conventional arrangements combining thrust bearings and radial bearings, rigidity can be increased by approximately 3–4 times, depending on the design and operating conditions. The bearing maintains stable support rigidity even under overturning moments.

High Rotational Accuracy: The integrated inner ring is suitable for applications in which the inner ring rotates, providing stable, micron-level rotational accuracy. The split-ring design also allows clearance adjustment, and high rotational accuracy can be maintained when preload is properly applied.

Compact, Thin-Walled Design: The inner and outer rings feature a compact profile and thin cross-section, minimizing installation space and helping reduce the overall weight of the equipment. This makes the bearing suitable for precision machinery with limited mounting space.

Applications

• Industrial Robots: Robot joints, rotary joints, and rotating components in robotic manipulators.
• Machine Tools: Rotary tables in machining centers, indexing tables, and direct-drive torque motors.
• Precision Measurement: Precision rotary tables, metrology instruments, and precision inspection equipment.
• Medical and Semiconductor Equipment: Medical instruments, semiconductor manufacturing equipment, and IC production machinery.
• Other Applications: Hollow rotary platforms and CNC indexing heads.

Key Application Areas: Equipment requiring high inner-ring rotational accuracy, including machine-tool indexing tables, inner-rotor direct-drive motors, and other rotary components.

Installation and Operating Guidelines

1. Preparation Before Installation

Cleaning and Inspection: Thoroughly clean the bearing housing, shaft, and mating components. Ensure that all surfaces are free from burrs, sharp edges, and contaminants.

Environmental Requirements: Maintain a clean, dust-free working environment. Keep hands dry and avoid contaminating the bearing during handling and installation.

2. Key Installation Procedures

Alignment Correction (Critical Step)

Slight misalignment may occur at the joints of the split inner and outer rings. Before fitting the bearing into its housing, loosen the inner- or outer-ring fastening bolts as appropriate and use a plastic mallet to correct the alignment. When the fastening rivets are driven into position, slight deformation may help compensate for minor misalignment.

Careful and Even Installation

RB 2008 is a thin-walled bearing and can tilt easily during installation. Keep the bearing level throughout the process. Use a plastic mallet to tap evenly around the circumference, gradually seating the bearing in place. Check that the bearing is fully and uniformly seated against the mating surface.

Axial Fixation

Axial fixation is achieved using a clamping flange or retaining plate. The flange should press against the appropriate side of the inner or outer ring, depending on the mounting arrangement. Strictly control the dimensional tolerances of all mating components to ensure that the flange secures the bearing properly.

3. Prohibited Practices

Do Not Disassemble the Bearing

The split-ring components are secured by rivets or bolts and should not be separated during normal installation or use. Incorrect reassembly of the cage or spacers can seriously impair rotational performance.

Do Not Apply Additional Impact Forces to Fasteners

Do not strike the fastening rivets or bolts during installation or removal, as this may deform or damage the fasteners.

Observe the Correct Removal Direction

When removing the outer ring, do not push the inner ring inward. When removing the inner ring, do not push the outer ring outward. It is recommended that threaded removal holes be provided in the support housing so that bolts can be used to push the bearing out, minimizing the risk of impact damage.

Preload and Clearance Adjustment

The inner and outer rings of RB series bearings have a split-ring design that allows clearance adjustment. Preload can be controlled by adjusting the spacing between the ring sections, using adjustment shims, or regulating the clamping torque.

When properly applied, preload helps maintain high rotational accuracy and improves bearing rigidity. The appropriate preload value should be determined with reference to the manufacturer’s product catalog and actual operating conditions, including the required rigidity, allowable torque, and temperature rise.

Lubrication and Maintenance

RB 2008 bearings are supplied with grease pre-filled at the factory, except for special orders. Under normal operating conditions, they can generally be installed and used without additional initial lubrication.

Routine Maintenance: Depending on operating conditions, replenish or replace the grease every 1–6 months as a general maintenance guideline. Both grease lubrication and oil lubrication are supported. The actual lubrication method and maintenance interval should be determined according to the operating speed, load, temperature, environment, and manufacturer’s recommendations.