Original THK Cross-Roller Ring RU/RB/RA Series - Precision Rotation for Robots
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Highlight
THK Cross-Roller Ring RU series
,Precision rotation bearing for robots
,Linear guide bearing with warranty
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Bearing TypeCross-Roller Ring (Cylindrical)
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Mounting TypeIntegral Mounting Holes (RU Series)
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Friction ControlPatented Spacer Retainer Technology
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Rigidity ClassHigh Rigidity (H-Series Available)
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Accuracy LevelUSP (Ultra-Super Precision) Grade Available
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Brand OriginJapan (100% Genuine THK)
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Shipping TermInternational Express（DHL/FEDEX/TNT/UPS/ARAMEX）/sea Freight / Air Freight / International Special Line
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Freight ChargeFor 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
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Place of OriginJapan
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CertificationISO、JIS、RoHS、The Original LM System
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Minimum Order Quantity1
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Price$250 - $1800
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Packaging DetailsOriginal
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Delivery Time3-5Workdays
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Payment TermsL/C,D/A,D/P,T/T,Western Union
Original THK Cross-Roller Ring RU/RB/RA Series - Precision Rotation for Robots
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 |
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| 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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