The RA18013 Cross Roller Bearing is a thin-section precision bearing with a 180 mm bore, 206 mm outside diameter and 13 mm width. Its 13 mm radial section provides a large central opening while maintaining useful rigidity for medium-to-large rotary mechanisms.
Crossed cylindrical rollers allow one compact bearing position to support radial loads, axial loads in both directions and tilting moments. The separable outer ring and one-piece inner ring make this model particularly suitable for precision inner-ring rotation.
Key specifications:
Dimensions: 180 × 206 × 13 mm
Roller pitch circle diameter: 192 mm
Basic dynamic radial load rating: 24.5 kN
Basic static radial load rating: 49.8 kN
Reference mass: 0.68 kg
Preferred configuration: inner-ring rotation
Available open, sealed and controlled-clearance options
The RA18013 Cross Roller Bearing is suitable for robot axes, rotary inspection stages, precision indexing units, semiconductor equipment and medical positioning systems requiring a large service passage.
Final clearance, accuracy, lubrication and interchangeability must be confirmed against the approved LYDL drawing.
RA18013 Cross Roller Bearing – 180 × 206 × 13 mm Thin-Section Precision Ring
The RA18013 Cross Roller Bearing combines a 180 mm clear bore with a compact 206 mm outside diameter and 13 mm width. It is designed for rotary systems that require a large service passage, low structural height and resistance to combined loading.
Alternately crossed cylindrical rollers contact the raceways along lines rather than points. This arrangement enables one bearing position to carry radial load, axial load from either direction and tilting moment.
RA18013 Quick Technical Data
Parameter
RA18013 specification
Product type
RA18013 Cross Roller Bearing
Bore diameter, d
180 mm
Outside diameter, D
206 mm
Width, B
13 mm
Radial section height
13 mm
Roller pitch circle diameter, dp
192 mm
Lubrication-hole reference a
2.5 mm
Lubrication-hole reference b
1.6 mm
Minimum chamfer, r min
0.8 mm
Maximum shaft shoulder, ds
185 mm
Minimum housing shoulder, Dh
199 mm
Basic dynamic radial rating, C
24.5 kN
Basic static radial rating, C0
49.8 kN
Reference mass
0.68 kg
Ring structure
One-piece inner ring, separable outer ring
Preferred precision rotation
Inner ring
The listed ratings follow the published RA18013 reference configuration. An approved LYDL drawing and order specification govern the supplied product.
Basic load ratings are reference values for standardized rating calculations. They are not universal permissible loads for every combination of radial force, axial force and overturning moment.
Why Choose the RA18013 Cross Roller Bearing?
The 180 mm bore provides space for cables, pneumatic lines, optical paths, drive shafts or inspection components. At the same time, the outside diameter is only 26 mm larger than the bore.
The bearing therefore has a 13 mm radial section and a 13 mm axial width. This square-section geometry is useful when both radial envelope and assembly height are restricted.
Compared with RA17013, the RA18013 provides 10 mm more bore diameter. Its reference dynamic rating increases from 23.5 to 24.5 kN, while the static rating increases from 46.5 to 49.8 kN.
Compared with RA19013, it reduces the housing outside diameter from 216 to 206 mm. The reference rating difference is only 0.4 kN dynamically and 1.7 kN statically, although application life must still be calculated separately.RA18013 Cross Roller Bearing featuring a 180 mm clear bore, 206 mm outside diameter and compact 13 mm section.
Structure and Operating Benefits
Each cylindrical roller is arranged at approximately 90 degrees to the adjacent roller. The crossed arrangement creates a rigid bearing position capable of reacting to multiple load directions.
A spacer retainer helps separate adjacent rollers and promotes stable rotational torque. This makes the standard RA configuration appropriate for precision positioning and moderate rotary motion.
Key design benefits include:
Combined radial, axial and moment-load capability
Large bore relative to the outside diameter
Compact 13 mm installation width
One-piece inner ring for controlled inner-ring rotation
Reduced bearing-stack height compared with paired arrangements
Open, sealed and application-specific configurations
Clearance and accuracy selection for positioning requirements
The RA18013 Cross Roller Bearing is not automatically suitable for every high-speed or continuous-duty application. Speed, preload, lubrication, heat generation and housing rigidity must be evaluated together.
Typical RA18013 Applications
The 180 mm central opening makes this model especially useful when mechanical support must surround a service passage.
Typical applications include:
Medium-to-large industrial robot axes
Precision rotary inspection platforms
Machine-tool indexing and auxiliary rotary units
Semiconductor handling and automation equipment
Optical scanning and metrology stages
Medical imaging or positioning equipment
Manipulators with internal cable or hose routing
In medical equipment, the bearing must be validated as part of the complete machine. Standard industrial product data should not be treated as approval for life-critical use.
Engineering Inquiry – RA18013 Send us your radial load, axial load, overturning moment, speed, duty cycle, required runout, operating temperature and lubrication conditions.
LYDL can recommend the appropriate seal, clearance, accuracy and lubrication configuration before quotation.
Mounting Recommendations
The RA outer ring is separable, while the inner ring is manufactured as one piece. For applications requiring controlled running accuracy, inner-ring rotation is normally preferred.
Use a stiff, accurately machined housing and flange. At a 206 mm outside diameter, uneven flange pressure or housing deflection can produce localized raceway loading.
Tighten clamping bolts gradually in a diagonal sequence. Apply uniform pressure around the full circumference rather than forcing one section into position.
Observe the specified 0.8 mm minimum chamfer and the recommended shoulder limits. Confirm all shoulder dimensions against the final LYDL drawing before machining production parts.
Do not strike the unsupported ring or apply installation force through the rollers. Keep the bearing clean and protect open versions from dust, coolant and metal particles.
For small-angle oscillation, review lubrication carefully because repeated motion over a short stroke may not rebuild a complete lubricant film. Periodic full rotation can help redistribute lubricant where the machine design permits.
Standard cross-roller-ring guidance normally limits service temperature to below 80°C. Contact LYDL for high temperature, vacuum, cleanroom, corrosion-resistant or special-grease requirements.supports compact rotary motion in robot joints, optical stages, semiconductor equipment and inspection systems.
Suffix meanings are not identical across manufacturers. Always place an order using the full designation, required clearance, accuracy class, seal arrangement and approved drawing number.
P4 or P2 should not be presented as a universal standard-stock RA18013 configuration. Availability depends on manufacturing feasibility, inspection criteria and the agreed application requirement.
Brand Designation Differences
Different manufacturers may use different prefixes and suffix systems for bearings with similar dimensions.
Brand or market system
Common designation example
LYDL
RA18013, RA18013UU, RA18013C or RA18013CUU
THK
RA 18013 or sealed RA 18013UU
IKO
CRBS 18013, CRBS 18013 AUU, CRBS 18013 V or VUU
Schaeffler/INA
SX or XSU family naming; select by dimensions and design
Aftermarket suppliers
XRA18013 or SRA18013 may be used
IKO CRBS 18013 shares the 180 × 206 × 13 mm boundary dimensions. However, IKO publishes 21.5 kN dynamic and 44.6 kN static ratings for its standard cage version, compared with 24.5 and 49.8 kN in the THK RA reference table.
This rating difference shows why matching dimensions alone does not prove complete interchangeability. Verify ring construction, seals, clearance, preload, accuracy, shoulder geometry, lubrication and rotational torque.
Select the smaller bearing only when its central passage, rating and stiffness remain adequate. Select the larger bearing when service routing, structural interface or calculated safety margin requires it.
For broader comparisons, see the RA Series Cross Roller Bearing Selection Guide and the complete LYDL Cross Roller Bearings range.dimensions, clearance, runout and rotational torque before protective export packaging.
Inspection and Supply Options
Available inspection documents can be defined during quotation. Requirements should be agreed before production rather than added after completion.
Possible documentation includes:
Boundary-dimension inspection report
Radial or axial runout inspection
Clearance or preload confirmation
Rotational-torque inspection
Material and hardness traceability
Lubricant and seal identification
RoHS or REACH declaration when applicable
Custom labeling and export packaging
RA18013 Cross Roller Bearing FAQ
1. Why does RA18013 have a 13 × 13 mm section?
Its radial section height is calculated as (206 − 180) ÷ 2 = 13 mm, and its width is also 13 mm. This geometry provides a large bore with a compact square-section envelope.
2. When should I choose RA18013 instead of RA19013?
Choose the RA18013 Cross Roller Bearing when a 180 mm bore is sufficient and the housing must remain within 206 mm. RA19013 provides a 190 mm bore and slightly higher ratings but requires a 216 mm outside diameter.
3. Is IKO CRBS18013 a direct replacement for RA18013?
Not automatically. The boundary dimensions may match, but published load ratings, roller retention, seals, clearance codes and accuracy systems can differ.
Confirm the complete IKO designation and compare it with the approved LYDL specification before replacement.
4. Is RA18013 intended for inner-ring rotation?
Yes. The one-piece inner ring and separable outer-ring structure are normally selected where accurate inner-ring rotation is required.
Outer-ring rotation should be reviewed separately because mounting rigidity and split-ring support influence performance.
5. Is the entire 180 mm bore available for cables or optics?
The bearing bore is nominally 180 mm, but the usable system passage also depends on the shaft shoulder, fasteners, covers and cable bend radius. Check the complete assembly in CAD before finalizing the design.
6. Why is housing stiffness important for this model?
A thin bearing can follow deformation in the adjacent structure. Uneven support around the 206 mm outer diameter may change preload, running torque and load distribution.
A continuous, accurately machined flange is therefore recommended.
7. Can the RA18013 operate in short-stroke oscillation?
Yes, subject to proper application review. Repeated small-angle motion can increase fretting risk if the rollers do not redistribute lubricant.
Provide the oscillation angle, frequency, load and operating time when requesting a recommendation.
8. What information is required for an RA18013 quotation?
Provide quantity, ring rotation, radial and axial loads, moment load, speed, duty cycle, required runout, operating temperature, environment, seals and lubrication preference.
A drawing of the shaft, housing and clamping flange will improve interchangeability and mounting review.
