RU Series
Integrated Mount Crossed Roller Bearings
10–350mm Bore | Pre-Drilled Mounting Holes | No Flange Needed | P5/P4/P2 Grade
The RU series (IKO equivalent: CRBF) features pre-drilled and counterbored mounting holes on both inner and outer rings — eliminating the need for separate flanges, presser plates, or custom housings. Simply bolt the bearing directly into your assembly. The preferred choice for harmonic drive reducers, robot base joints, and direct-drive motor integrations.
Ready-to-Mount Crossed Roller Bearings with Integrated Bolt Holes for Simplified Assembly
Luoyang Songju RU series (IKO CRBF equivalent) crossed roller bearings are the ultimate "bolt-on" solution — featuring precision-drilled and counterbored mounting holes on both inner and outer rings. This eliminates the engineering, machining, and assembly time required for separate flanges, presser flanges, or custom housings — significantly reducing total system cost and lead time.
The integrated inner/outer ring structure ensures high rigidity and stable rotational accuracy without the need for post-installation clearance adjustment. POM plastic separators between each cylindrical roller enable smooth, low-friction rotation suitable for continuous-duty applications. The pre-drilled hole pattern is standardized across each size, ensuring compatibility with industry-standard harmonic reducer and robot joint interfaces.
Available in P5, P4, and P2 precision grades from GCr15 bearing steel. Standard models (AT suffix) are open type; sealed models (AT UU suffix) feature dual synthetic rubber seals. The series covers bore sizes from 10mm to 350mm, corresponding to THK RU and IKO CRBF mounting patterns for harmonic drive applications from size 14 through 45.
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RU Series — Integrated Mount Crossed Roller Bearing Model Parameters
Complete standard model list for RU series integrated mount crossed roller bearings. IKO equivalent: CRBF series. THK equivalent: RU series. All models include pre-drilled mounting holes on both rings.
| Bearing Model | d (mm) | D (mm) | B (mm) | Cr (kN) | C0r (kN) | Mass (kg) |
|---|---|---|---|---|---|---|
| RU 42 (CRBF 108) | 10 | 52 | 8 | 2.91 | 2.43 | 0.12 |
| RU 66 (CRBF 2012) | 20 | 70 | 12 | 7.6 | 8.37 | 0.31 |
| RU 85 (CRBF 2512) | 25 | 80 | 12 | 8.61 | 10.6 | 0.4 |
| RU 124 (CRBF 3515) | 35 | 95 | 15 | 17.3 | 20.9 | 0.66 |
| RU 148 (CRBF 5515) | 55 | 120 | 15 | 20.1 | 27.7 | 0.96 |
| RU 178 (CRBF 8022) | 80 | 165 | 22 | 51.1 | 72.0 | 2.63 |
| RU 228 (CRBF 9025) | 90 | 210 | 25 | 52.4 | 77.4 | 3.5 |
| RU 297 (CRBF 11528) | 115 | 240 | 28 | 73.4 | 108.0 | 4.8 |
| RU 350 (CRBF 16035) | 160 | 295 | 35 | 114.0 | 200.0 | 8.5 |
| RU 445 (CRBF 21040) | 210 | 380 | 40 | 183.0 | 367.0 | 15.0 |
| RU 550 (CRBF 35045) | 350 | 540 | 45 | 241.0 | 531.0 | 28.0 |
All models available in P5, P4, and P2 precision grades. IKO equivalent: CRBF series. THK equivalent: RU series. Standard: GCr15 bearing steel, POM separators, pre-drilled mounting holes. Suffix AT = open type. Suffix AT UU = double sealed. 3D CAD models available upon request.
Why Choose Luoyang Songju RU Series Integrated Mount Crossed Roller Bearings
Bolt-on simplicity — pre-drilled mounting holes eliminate flange design, machining, and assembly time
Pre-Drilled Mounting Holes — Ready to Bolt On
Both inner and outer rings feature precision-drilled, counterbored mounting holes in standardized patterns. Eliminates the need for separate presser flanges, custom housings, or post-installation machining — reducing total assembly cost and engineering lead time.
Integrated Ring Structure — No Adjustment Needed
The one-piece inner and outer ring construction maintains optimal preload and clearance as manufactured. No post-installation clearance adjustment required — simply bolt in place and achieve specified rotational accuracy immediately.
Bi-Directional Rotation Support
Pre-drilled holes on both rings enable flexible mounting: either ring can serve as the rotating element. This symmetry makes RU bearings ideal for both inner-ring-rotation (e.g., robot base joints) and outer-ring-rotation (e.g., harmonic drive output flanges) applications.
Harmonic Reducer Standard Interface
RU bearing sizes directly correspond to harmonic drive reducer frame sizes: RU 42 (size 14), RU 66 (size 17), RU 85 (size 20), RU 124 (size 25), RU 148 (size 32), RU 178 (size 40), RU 228 (size 45). Drop-in compatible with major harmonic drive brands.
Open & Sealed Configurations
Standard AT type (open) for oil-bath or grease lubrication with external sealing. AT UU type with dual synthetic rubber seals for grease retention and contamination exclusion. Operating temperature range: -20°C to +110°C (sealed type).
CAD Data Available
3D CAD models (STEP, IGES) and 2D drawings (PDF, DWG) available for all standard RU sizes. Speed your design process with ready-to-integrate mounting geometry — contact our engineering team for download access.
Industries & Applications for RU Series Integrated Mount Crossed Roller Bearings
RU Series crossed roller bearings are trusted across a wide range of precision industries worldwide.
Harmonic Drive & Cycloidal Reducers
RU bearings are the de facto standard output bearing for harmonic drive reducers. Integrated mounting holes directly interface with the flexspline and circular spline bolt patterns — eliminating custom bearing housing design for reducer manufacturers and robot OEMs.
Robot Base & Shoulder Joints
Large RU bearings (RU 178–550) serve as the primary rotary bearing in robot base joints, shoulder pivots, and heavy-payload cobot arms. The bolt-on design simplifies robot joint structure and reduces assembly part count by 30–50% versus traditional flanged bearing arrangements.
Direct-Drive Rotary Motors
RU bearings integrate seamlessly into DD motor housings for CNC rotary axes, semiconductor wafer stages, and precision inspection turntables. Pre-drilled holes align with standard DD motor mounting patterns for plug-and-play integration.
Antenna & Optical Pedestals
Military and commercial antenna pedestals, optical tracking mounts, and LIDAR platforms. RU bearings provide the rigid, low-profile rotary interface needed for precision azimuth/elevation positioning in harsh outdoor and mobile environments.
Need RU Series Integrated Mount Crossed Roller Bearings?
Tell us your bore size, precision grade, seal preference, bolt hole pattern requirement, and quantity. Our engineers will respond within 24 hours with a quotation and CAD data.