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                                                                                                                                                                                                                                    THK Cross-Roller Ring RU series, Precision rotation bearing for robots, Linear guide bearing with warranty
                      

Bearing Type:	Cross-Roller Ring (Cylindrical)	Mounting Type:	Integral Mounting Holes (RU Series)
Friction Control:	Patented Spacer Retainer Technology	Rigidity Class:	High Rigidity (H-Series Available)
Accuracy Level:	USP (Ultra-Super Precision) Grade Available	Brand Origin:	Japan (100% Genuine THK)
Shipping Term:	International Express（DHL/FEDEX/TNT/UPS/ARAMEX）/sea Freight / Air Freight / International Special Line	Freight Charge:	For Industrial Equipment (e.g., PLC Modules, Inverters..), Shipping Cost Varies By Package Weight/volume And Delivery Location. Contact Our Sales Team For A Customized Shipping Solution And Quote

Bearing Type:	Cross-Roller Ring (Cylindrical)
Mounting Type:	Integral Mounting Holes (RU Series)
Friction Control:	Patented Spacer Retainer Technology
Rigidity Class:	High Rigidity (H-Series Available)
Accuracy Level:	USP (Ultra-Super Precision) Grade Available
Brand Origin:	Japan (100% Genuine THK)
Shipping Term:	International Express（DHL/FEDEX/TNT/UPS/ARAMEX）/sea Freight / Air Freight / International Special Line
Freight Charge:	For Industrial Equipment (e.g., PLC Modules, Inverters..), Shipping Cost Varies By Package Weight/volume And Delivery Location. Contact Our Sales Team For A Customized Shipping Solution And Quote

Original THK Cross-Roller Ring RU/RB/RA Series - Precision Rotation for Robots

THK, the pioneer of global Linear Motion (LM) systems, sets the industry standard with its Cross-Roller Ring series. In this specialized field, the THK RU Series (with integrated mounting holes) is regarded as the quintessential component for high-performance robotics. While other brands may focus on compactness or material life, THK excels in "ultimate rotational accuracy" and "universal adaptability." By arranging cylindrical rollers perpendicularly in a 90° V-groove and utilizing patented Spacer Retainers, THK eliminates friction between rollers to achieve sub-micron level runout accuracy. These bearings are the soul of the world's top collaborative robots, surgical tables, and semiconductor handling arms.

Product Highlights

RU Series Integrated Mounting Holes: Both inner and outer rings feature pre-drilled mounting holes, allowing direct fixation without flanges or housing covers. This drastically simplifies assembly and minimizes cumulative error.
Spacer Retainer Technology: THK's patented spacer design prevents roller skewing and mutual friction, ensuring extremely low torque fluctuation even at high speeds.
Peak Rotational Accuracy (USP Grade Available): Offers up to USP (Ultra-Super Precision) grade runout control, meeting the extreme demands of semiconductor fabrication and surgical robotics.
H Series High Rigidity Enhancement: The newly introduced RB-H/RE-H/RU-H series offers dimensional interchangeability with existing products while providing enhanced rigidity for high-impact industrial environments.
Comprehensive Structural Matrix: From the standard RB to the outer-ring rotating RE, and the ultra-slim RA/RA-C, THK provides the most complete selection of cross-roller bearings in the world.
Omni-Directional Load Handling: A single THK cross-roller ring can replace two conventional bearings, significantly reducing the axial length of rotary joints.

Core Parameter Table (Key Series)

Series	Structural Features	Precision Class	OD Range (mm)	Core Advantage	Typical Application
RU	Integrated Mounting Holes	P5 / P4 / P2	35 - 350	Plug & Play Integration	Cobot Joints, Medical RTs
RB / RB-H	Separable Outer Ring	P5 / P4 / USP	70 - 1500	Robust Load Capacity	Spindles, Industrial Arms
RE / RE-H	Separable Inner Ring	P5 / P4 / USP	70 - 1500	Outer-Ring Rotation	Revolving Doors, Heavy Automation
RA / RA-C	Thin-Walled / Compact	P5 / P4	66 - 226	Extreme Lightweight	Surgical Robots, Small Arms
VR / VRG	Cross-Roller Guide	Ultra-Precision	N/A	Smooth Linear/Curved Motion	Vision Stages, Pick & Place

Application Fields

Collaborative Robotics (Cobots): Main support bearings for axes 1-6; the RU series is particularly favored for its minimalist assembly.
Semiconductor & Electronics: Wafer dicing machines, AOI (Automated Optical Inspection) turntables, and precision die bonders.
Precision Medical Equipment: Final joints for surgical robots, high-precision CT scanner tables, and radiotherapy gantry rotation.
High-End Machine Tools: CNC indexing tables, 4th/5th axis rotary heads, and Automatic Tool Changers (ATC).
Aerospace & Defense: Satellite antenna pitch mechanisms and ground-tracking station rotary bases.

Frequently Asked Questions

Q: Why is the THK RU series so popular in the robotics industry?

A: Primarily because of its integrated mounting holes. You don't need to design complex flanges to secure it, which saves costs and reduces assembly errors caused by machining tolerances.

Q: How do you guarantee these are 100% genuine Japanese THK products?

A: We deal directly with authorized THK channels. Every unit carries an official THK anti-counterfeit label and supports factory serial number tracking, ensuring original THK material quality.

Q: What is the difference between the RA and RA-C series?

A: RA is the standard thin-walled type; RA-C is a compact version optimized for improved stability when the outer ring rotates.

Q: What happens if the bolt pre-tension is uneven during installation?

A: This is dangerous. Uneven pre-tension can cause slight bearing deformation, leading to rotation jitter or loss of precision. We recommend following THK's torque specifications using a diagonal cross-tightening sequence.

Q: Can these bearings be used in high-vacuum environments?

A: Yes. THK offers specialized vacuum greases (e.g., AFE-CA) and options for ceramic balls or stainless steel components for semiconductor fabrication in vacuum.

Q: What is the typical lead time?

A: We stock common models like the RU124, RU148, and RB14025 (1-2 weeks). Large-diameter or H-series high-rigidity models typically require 10-14 weeks factory lead time.

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Original THK Cross-Roller Ring RU/RB/RA Series - Precision Rotation for Robots

THK Cross-Roller Ring RU series

Precision rotation bearing for robots

Linear guide bearing with warranty

THK Cross-Roller Ring RU series,

Precision rotation bearing for robots,