The RU66 cross roller bearing is a compact and reliable mounting-holed bearing with a 35 mm bore, 95 mm outside diameter and 15 mm width. Its integrated inner and outer rings simplify assembly, while crossed cylindrical rollers support radial loads, axial loads in both directions and overturning moments.
With dynamic and static radial load ratings of 17.5 kN and 22.3 kN, the RU66 cross roller bearing is well suited to compact robot joints, cobot wrists, rotary actuators, inspection stages and laboratory automation.
LYDL supplies open RU66 and double-sealed RU66UU versions. P5, P4 and P2 accuracy, controlled clearance or preload, special grease, low-torque configuration, OEM marking and inspection reports are available on request.
RU66 Cross Roller Bearing Overview
The RU66 cross roller bearing is a compact mounting-holed bearing designed for precision rotary mechanisms with limited installation space. Its principal dimensions are 35 mm bore, 95 mm outside diameter and 15 mm width.
As part of the RU series crossed roller bearings, RU66 uses integrated inner and outer rings with mounting holes on both rings. It can be bolted directly to accurately machined supporting components, helping reduce the number of separate housings, flanges and locating parts.
Cylindrical rollers are arranged alternately at 90 degrees. This allows the RU66 cross roller bearing to support radial loads, axial loads in both directions and overturning moments within one compact bearing unit.
Why RU66 Is Different
Compact 95 mm outside diameter
Useful 35 mm center passage
Integrated inner and outer rings
Direct mounting holes on both rings
High rigidity within a 15 mm width
Suitable for inner- or outer-ring rotation
Open and double-sealed options
Precision and low-torque configurations available
RU66 Cross Roller Bearing Specifications
Parameter
RU66 Specification
Bearing type
Mounting-holed cross roller bearing
Ring construction
Integrated inner and outer rings
Bore diameter, d
35 mm
Outside diameter, D
95 mm
Width, B
15 mm
Roller pitch circle diameter, dp
66 mm
Minimum chamfer, r min.
0.6 mm
Greasing-hole diameter, d1
3.1 mm
Reference shoulder diameter, ds max.
59 mm
Reference housing shoulder diameter, Dh min.
74 mm
Inner-ring mounting PCD
45 mm
Inner-ring mounting holes
8 × M4 through
Outer-ring mounting PCD
83 mm
Outer-ring mounting holes
8 × Ø4.5 mm through
Outer-ring counterbore
Ø8 mm, depth 4.4 mm
Basic dynamic radial load rating, C
17.5 kN
Basic static radial load rating, C₀
22.3 kN
Approximate mass
0.62 kg
Standard material
GCr15 / 100Cr6 bearing steel
Available accuracy
P5, P4 and P2
Supported loads
Radial, bidirectional axial and moment
The stated RU66 cross roller bearing load ratings are radial catalog values. Actual service life should be calculated using the combined radial load, axial load, overturning moment, speed, operating cycle, lubrication and mounting conditions.
RU66 Cross Roller Bearing Design Benefits
Compact Radial Envelope
RU66 provides a 35 mm bore within a 95 mm outside diameter. This balance is useful in robot wrists and compact rotary actuators where the bearing must carry moment loads without making the joint excessively large.
Although RU66 and RU85 both have a width of 15 mm, RU66 has a 25 mm smaller outside diameter. It is therefore better suited to smaller joints and lightweight rotary modules.
Integrated Mounting Structure
Both rings are integrated and contain mounting holes. This reduces assembly sensitivity compared with bearings that use a split ring and normally simplifies the surrounding support structure.
Direct mounting can reduce component count, but it does not remove the need for rigid, flat and accurately machined mounting surfaces.
35 mm Center Passage
The center opening can be used for a drive shaft, electrical cables, pneumatic lines or sensor wiring. Before selection, allow sufficient clearance for cable movement and protective sleeves rather than using the full nominal bore diameter.
Combined-Load Capability
Crossed cylindrical rollers provide line contact with the raceways. The bearing can resist radial force, bidirectional axial force and overturning moment simultaneously, making it a compact alternative to some multi-bearing arrangements.
Explore the complete cross roller bearing range when a different ring structure or mounting method is required.
RU66 Cross Roller Bearing Variants and Order Options
Clean equipment or systems with external protection
RU66UU
Sealed on both sides
Improved contamination protection and grease retention
C0
Positive radial clearance
Lower starting torque
CC0
Controlled preload or negative clearance
Higher rigidity and positioning stability
P5
Precision grade
General automation
P4
High-precision grade
Robot joints and inspection equipment
P2
Ultra-high-precision grade
Metrology and demanding positioning systems
Low-torque configuration
Controlled grease, seals and internal condition
Small servo motors and sensitive motion axes
Special lubrication
Application-selected grease or lubricant
Temperature, cleanroom or vacuum requirements
OEM marking
Customer model, logo or serial number
Private-label and traceability projects
A typical purchasing description may be written as: RU66UU / P4 / CC0 / low-torque grease The approved LYDL drawing and purchase order should define the final configuration. Suffix order can differ between manufacturers, so accuracy, clearance, preload, seals and lubricant should also be stated in words.
Open RU66 or Sealed RU66UU?
Open RU66 generally provides lower seal resistance and suits equipment operating in a clean environment or using external sealing.
RU66UU has seals on both sides to improve grease retention and reduce contamination. It is often selected for robot joints and automation modules that are not opened regularly for maintenance.
For compact servo axes, seal drag and preload can materially affect motor starting torque. Customers using a small motor or direct-drive design should specify both the required rigidity and acceptable rotational torque.
RU66 Cross Roller Bearing Applications
Compact Robot and Cobot Joints
The 95 mm outside diameter helps control joint size, while the 35 mm bore allows space for shafts, cables or pneumatic lines. Typical positions include cobot wrists, small arm joints and end-effector rotation axes.
Precision Rotary Actuators
RU66 can support combined loading in compact servo-driven modules. Its mounting-hole design helps integrate the bearing with motor housings and output flanges.
Optical and Electronic Inspection
The bearing is suitable for camera rotation stages, optical inspection mechanisms and sensor platforms requiring repeatable angular positioning.
Laboratory and Medical Automation
RU66 can be used in sample-handling mechanisms, compact scanners and laboratory rotary stages where low weight and a small installation envelope are important.
Select RU66 when a 35 mm passage, compact 95 mm outside diameter and substantially higher load ratings than RU42 are required.
Select the RU85 cross roller bearing when a 55 mm bore, larger mounting interface or higher static-load capacity is needed.
The comparison above is for preliminary selection. Review the actual loads, moment arm, speed, accuracy and required life before confirming a model. Additional selection guidance is available in the cross roller bearing guide.
A reference number indicates similar boundary dimensions and mounting features, not guaranteed automatic interchangeability. Load ratings can also differ between brand catalogs.
Before replacement, compare:
35 × 95 × 15 mm boundary dimensions
Inner-ring PCD and M4 threads
Outer-ring PCD, through holes and counterbores
Seal construction
Shoulder dimensions
Accuracy and runout tolerances
Clearance or preload
Starting and running torque
Dynamic and static load ratings
Lubricant and operating temperature
THK and IKO are trademarks of their respective owners. They are used only for model identification and dimensional comparison. LYDL is an independent bearing manufacturer and is not affiliated with or endorsed by these companies.
RU66 Cross Roller Bearing Installation
Clean the bearing, mounting faces and bolt holes before assembly.
Remove burrs, metal particles and surface contamination.
Check the 45 mm and 83 mm mounting PCDs against the approved drawing.
Confirm that the M4 bolts have sufficient engagement without bottoming out.
Place the bearing onto the mounting surface without hammering or impact.
Install all bolts loosely before applying final torque.
Tighten the bolts gradually in a diagonal sequence.
Rotate the bearing during staged tightening to detect abnormal resistance.
Measure radial and axial runout after assembly.
Confirm running torque before connecting the final servo settings.
Because RU66 is frequently used with compact motors, excessive preload, seal drag, misalignment or uneven bolt tightening may cause more noticeable changes in drive torque.
RU66 Cross Roller Bearing Inspection and Packaging
LYDL can inspect each bearing according to the selected accuracy, preload and documentation requirements.
Available Inspection Items
Bore, outside diameter and width
Mounting-hole diameter and PCD
M4 thread inspection
Ring roundness and raceway geometry
Material hardness
Radial clearance or preload
Starting and running torque
Radial and axial runout
Rotation smoothness and noise
Appearance, marking and serial number
Inspection reports, material certificates and traceability documents can be supplied when requested before production.
After inspection, the bearing receives anti-rust protection and sealed or vacuum packaging. Shock-resistant material, individual cartons and reinforced plywood cases are available for international transportation.
Why Source RU66 Cross Roller Bearings From LYDL?
LYDL manufactures precision bearings in Luoyang, China. Production and quality-control capabilities cover machining, raceway grinding, superfinishing, component sorting, cleaning, assembly, preload control and final inspection.
Available order options include:
Open RU66 or sealed RU66UU
P5, P4 or P2 accuracy
Controlled clearance or preload
Low-torque grease and seal selection
Customer model and serial marking
Dimensional and material reports
OEM packaging
Application and interchange review
RU66 Cross Roller Bearing FAQ
Why is RU66 suitable for compact cobot wrists?
RU66 combines a 95 mm outside diameter with a 35 mm center opening and 15 mm width. This provides room for internal wiring while keeping the wrist structure relatively compact.
How much of the 35 mm bore can be used for cables?
The full nominal bore should not normally be filled. Allow clearance for cable bending, protective sleeves, connector movement and manufacturing tolerances.
Can RU66 operate continuously at high speed?
RU66 is primarily selected for rigidity and precision positioning rather than very high-speed rotation. Continuous speed capability depends on load, preload, lubrication, sealing, heat dissipation and required life.
Why does RU66UU require more servo torque than open RU66?
The seals create additional friction. Preload and grease consistency can further increase starting torque. A low-torque specification should therefore be confirmed when using a small servo motor.
When should RU85 be selected instead of RU66?
Choose RU85 when the equipment requires a larger 55 mm center opening, a wider mounting interface or higher static-load capacity. RU66 is preferable when the 35 mm bore is sufficient and minimizing joint diameter is more important.
Can RU66 replace CRBF3515AT without redesign?
The models have commonly referenced dimensions, but the drawings, hole pattern, load ratings, seals, clearance, accuracy and rotational torque must be compared before replacement approval.
Request a Reliable RU66 Cross Roller Bearing Quote
For accurate selection and pricing, send the required quantity, load conditions, speed, operating cycle, rotating ring, accuracy, clearance or preload, sealing, temperature and lubrication requirements. Contact the LYDL engineering team for an RU66 drawing, selection review, production lead time and export quotation.
Technical References
THK, Cross-Roller Ring—Model RU, Integrated Inner and Outer Rings.
IKO, CRBF Crossed Roller Bearings with Mounting Holes.
ISO 281, Rolling Bearings—Dynamic Load Ratings and Rating Life.
