Possible Combinations of Crossed Roller Bearings

1. Single Bearing Configuration

• One crossed roller bearing supports combined loads.

• Compact design with high rigidity.

• Common in robotic joints and precision rotary tables.

Advantage: Simplified structure and minimal space requirement.

2. Back-to-Back Arrangement (DB Configuration)

• Two crossed roller bearings mounted with load lines diverging outward.

• Provides higher moment rigidity and improved overturning resistance.

• Suitable for heavy-load rotary platforms and precision machine tools.

Advantage: Maximum structural stiffness and axial stability.

3. Face-to-Face Arrangement (DF Configuration)

• Two bearings mounted with load lines converging inward.

• Better tolerance for shaft misalignment.

• Used in applications requiring alignment flexibility.

Advantage: Improved mounting tolerance.

4. Tandem Arrangement (DT Configuration)

• Bearings mounted in the same load direction.

• Increases axial load capacity in one direction.

• Applied in systems with dominant one-way axial loads.

Advantage: Higher axial capacity without increasing bearing size.

5. Preloaded Pair Combination

• Bearings supplied with controlled preload.

• Eliminates internal clearance and increases rotational accuracy.

• Ideal for high-precision CNC and semiconductor equipment.

Advantage: Enhanced positioning accuracy and reduced vibration.

Components of a Crossed Roller Bearing and Their Materials

1. Inner Ring

Function:
Provides one raceway surface and is mounted to the shaft or rotating element.

Typical Materials:

• High carbon chromium bearing steel (GCr15 / AISI 52100)

  • High hardness (HRC 58–64 after heat treatment)

  • Excellent rolling fatigue resistance

• Carburized alloy steel (e.g., 20CrMnTi)

  • Used for heavy-duty or impact-load applications

• Stainless steel (AISI 440C)

  • For corrosion-resistant environments

2. Outer Ring

Function:
Forms the outer raceway and is fixed to the housing or structural frame.

Typical Materials:

• GCr15 / AISI 52100 bearing steel (standard use)

• Alloy structural steel (large-diameter or slewing types)

• Stainless steel (corrosive environments)

3. Cylindrical Rollers

Function:
Rolling elements arranged alternately at 90° to support radial, axial, and moment loads simultaneously.

Typical Materials:

• High carbon chromium steel (GCr15 / AISI 52100)

  • High dimensional accuracy

  • Superior wear and fatigue resistance

• Ceramic rollers (Si₃N₄ – silicon nitride)

  • Lightweight

  • Electrically insulating

  • High-speed capability

4. Cage or Spacer (Retainer)

Function:
Maintains proper roller spacing and prevents roller skewing or contact.

Typical Materials:

• Brass cage (HPb59-1 or similar)

  • High strength

  • Suitable for heavy-duty and high-precision use

• Engineering plastic (PA66 with glass fiber reinforcement)

  • Lightweight

  • Low noise

  • Used in high-speed or compact designs

• Steel spacer retainers

  • Common in high-rigidity industrial applications

5. Seals (Optional)

Function:
Protect internal components from dust, moisture, and contaminants.

Typical Materials:

• NBR (Nitrile Rubber) with steel reinforcement

• FKM (Viton) for high-temperature environments

6. Lubricant

Function:
Reduces friction, minimizes wear, and improves heat dissipation.

Typical Options:

• Lithium-based grease (general industrial)

• Synthetic grease (high-speed, precision equipment)

• Oil lubrication (high-speed CNC or automation systems)