THK RA9008CUUC0 Cross Roller Ring
RA9008CUUC0 is an ultra‑thin‑type crossed roller bearing (Cross‑Roller Ring) from THK’s RA‑C series, featuring a single‑split outer ring for enhanced rigidity and versatility. It supports both inner‑ring and outer‑ring rotation, with cylindrical rollers arranged perpendicularly in 90° V‑grooves via a precision spacer retainer.
RA9008CUUC0 is an ultra‑thin‑type crossed roller bearing (Cross‑Roller Ring) from THK’s RA‑C series, featuring a single‑split outer ring for enhanced rigidity and versatility. It supports both inner‑ring and outer‑ring rotation, with cylindrical rollers arranged perpendicularly in 90° V‑grooves via a precision spacer retainer. This design enables the bearing to withstand radial, axial, and moment loads simultaneously in an ultra‑slim profile. The model is factory‑equipped with double rubber contact seals (UU) and standard radial clearance (C0), providing contamination resistance and stable rotational performance.
Official Technical Specifications
| Parameter | Value | Unit |
|---|---|---|
| Model | RA9008CUUC0 | — |
| Inner Diameter (d) | 90 | mm |
| Outer Diameter (D) | 106 | mm |
| Width (B) | 8 | mm |
| Roller Pitch Circle Diameter (dp) | 97 | mm |
| Minimum Chamfer (rₘᵢₙ) | 0.5 | mm |
| Shaft Fit Diameter (dsₘₐₓ) | 93.5 | mm |
| Housing Fit Diameter (Dhₘᵢₙ) | 100.5 | mm |
| Greasing Hole (d₀) | 1.5 | mm |
| Basic Dynamic Load Rating (C) | 6.76 | kN |
| Basic Static Load Rating (C₀) | 12.4 | kN |
| Mass | 0.12 | kg |
| Internal Clearance | C0 | Standard radial clearance (THK normal clearance) |
| Seal Type | UU | Double rubber contact seals (both sides) |
| Retainer | Spacer retainer | Precision roller guidance |
| Lubrication | AFB‑LF Grease | Factory‑filled lithium‑base grease |
| Operating Temperature | -15°C to +80°C | Standard service range |
| Accuracy Class | P0 (PN2) | ISO 492 / ABEC 1 |
Key Design Features
- Single‑Split Outer Ring: High‑rigidity split outer ring design allows for both inner‑ring and outer‑ring rotation, expanding application flexibility compared to standard RA series.
- Ultra‑Thin & High Rigidity: Crossed roller arrangement delivers 3–4× higher rigidity than conventional double‑row thin angular contact bearings in an ultra‑slim profile.
- Multi‑Directional Load Capacity: Single bearing supports radial, axial, and moment loads, simplifying mechanical design and reducing component count.
- Stable Low Torque: Spacer retainers prevent roller skewing and eliminate roller‑to‑roller friction, ensuring consistent, smooth rotation.
- Contamination Protection: UU double seals block dust, chips, and coolant ingress, extending service life in industrial environments.
- Easy Installation: Pre‑assembled with rollers and retainer for direct installation; split outer ring simplifies mounting and alignment.
- Standard Clearance (C0): Factory‑set radial clearance ensures smooth operation and consistent performance under varying loads.
Typical Applications
- Precision rotary tables for small machine tools and measuring instruments
- Industrial robot joints and end‑effector rotary stages (supports outer‑ring rotation)
- Semiconductor manufacturing equipment (wafer handlers, inspection tools)
- Medical diagnostic and imaging equipment
- Optical positioning systems and precision automation modules
- Compact rotary actuators and lightweight robotic swiveling units
- High‑precision indexing tables and rotary actuators
Model Code Explanation (THK Standard)
| Code | Meaning |
|---|---|
| RA | Thin‑type cross‑roller ring series |
| 90 | Inner diameter = 90 mm |
| 08 | Width = 8 mm |
| C | Single‑split outer ring (RA‑C type) |
| UU | Double rubber contact seals (both sides) |
| C0 | Standard internal radial clearance (THK normal clearance) |
