1. Industry Working Condition Pain Points

In high-end equipment such as industrial robot joints, CNC rotary tables, precision testing equipment and medical rotating platforms, bearings face the harsh challenge of extremely limited space combined with complex multi-directional loads. Traditional ball bearings carry loads through point contact. Under heavy loads or overturning moments, stress concentration occurs at contact points, causing local deformation of raceways. This deformation is amplified by the arm length, manifesting as perceptible trajectory deviation and jitter at the robot end-effector.

 

More critically, many applications require large hollow passages for cables and sufficient overturning rigidity within limited height. Conventional solutions often employ multiple bearing combinations—thrust bearings for axial loads, radial bearings for radial loads, plus additional bearings for overturning moments. This stacking approach not only significantly increases axial dimensions and structural complexity, but the cumulative assembly errors of multiple bearings further degrade rotational accuracy. In scenarios such as collaborative robots, surgical robots and semiconductor vacuum transfer chambers with extreme demands on both space and precision, conventional solutions are no longer adequate.

 

Domestic crossed roller bearings commonly suffer from insufficient roller crowning control, weak cage strength and poor rolling consistency, leading to roller misalignment, cage fracture and torque fluctuation under heavy loads. Imported crossed roller bearings offer excellent performance but have long procurement cycles and high prices, making them unaffordable for small and medium manufacturers. Insufficient bearing rigidity causes end-effector jitter and machining vibration marks; space constraints force design compromises and functional concessions, severely undermining product competitiveness.

 

For applications requiring high rigidity, compact space, combined loads and long-term precision retention, professional crossed roller bearings with line-contact high rigidity, ultra-thin compact design and single-bearing multi-directional load capacity are urgently needed.

 

2. Product Core Positioning

Developed with Japanese precision bearing design and manufacturing experience, NMT crossed roller bearings focus on the dual requirements of compact space and high rigidity. The core structure features cylindrical rollers arranged at 90° perpendicularly in V-shaped raceways, with rollers separated by spacers to prevent tilting or mutual friction and avoid abnormal torque increase. This orthogonal dense arrangement transforms contact from the point contact of ball bearings to line contact, allowing stress to disperse evenly across raceway surfaces like flowing water—a single bearing simultaneously withstands radial loads, axial loads, overturning moments and other multi-directional combined loads.

 

The ultra-thin cross-section design minimises inner and outer ring dimensions to the extreme, approaching the limits of miniaturisation. Under the same load capacity, NMT crossed roller bearings have a far lower cross-section height than traditional multi-bearing combinations, while leaving an unobstructed hollow passage at the centre for cables and tubes to pass straight through, eliminating the fatigue fracture risk from repeated bending. Accuracy grades up to P4 and P2 are available, meeting diverse requirements from general precision equipment to high-end applications.

 

3. Structural Classification & Functional Advantages

(1) RB Series – Outer Ring Split Type

 

Outer ring split with integrated inner ring design, suitable for applications requiring high inner ring rotational accuracy. Rollers are arranged perpendicularly in V-shaped raceways separated by spacers. The split structure allows precise clearance adjustment, enabling high-accuracy rotational motion even under preload.

 

(2) RE Series – Inner Ring Split Type

 

Inner ring split with integrated outer ring design, suitable for applications requiring high outer ring rotational accuracy. Main dimensions are the same as RB series, catering to different rotational accuracy requirements.

 

(3) RU Series – Integrated Inner and Outer Ring Type

 

Both inner and outer rings are integrated structures with pre-machined mounting holes, eliminating the need for fixing flanges and support housings. Installation has minimal impact on performance, providing stable rotational accuracy and torque, suitable for applications where both outer and inner rings rotate.

 

(4) RA Series – Ultra-Thin Compact Type

 

A new type derived from RB series design, with inner and outer ring thickness reduced to the极限. Most suitable for applications requiring lightweight and compact design, such as collaborative robots, medical robotic arms and precision alignment platforms.

 

General advantages summary: Single bearing handles multi-directional combined loads, one replacing multiple combinations; line-contact structure improves rigidity by 3-4 times over ball bearings; ultra-thin cross-section significantly saves installation space with a central hollow for cabling; split structure allows precise clearance adjustment; accuracy grades up to P4 and P2 available.

 

4. Two-Grade Material & Process Selection

Grade 1: Through-Hardened Bearing Steel (General Version)

 

Integral quenching and low-temperature stabilizing tempering achieve uniform overall hardness with consistent raceway and roller wear resistance. Suitable for conventional industrial robot joints, CNC rotary tables and automation equipment under stable conditions, with outstanding cost performance for complete machine supporting.

 

Grade 2: Carburized Bearing Steel (Heavy-Duty Reinforced Version)

 

Inner rings, outer rings and rollers undergo deep carburizing quenching for hard wear-resistant surfaces with a tough matrix core for impact resistance. Applied to heavy-duty palletising robots, large radar antennas, shield machine main bearings and other impact-type combined load conditions, withstanding instantaneous peak loads and significantly extended service life under extreme conditions.

 

5. Japanese Precision Manufacturing Process

Vacuum degassing refining of high-purity special steel forging, controlling non-metallic inclusions to extremely low levels and eliminating fatigue crack initiation points;

 

Precision forging + gradient heat treatment, ensuring thin-section rings maintain stable geometric shapes after quenching, preventing warpage from residual stress release;

 

Fully closed-loop ultra-precision grinding system with nanoscale online measurement, achieving sub-micron raceway geometry accuracy;

 

Precise roller crowning profile control—strictly controlling roller crowning curves and raceway surface integrity to effectively reduce stress peaks in rolling contact areas, maintaining stable rotational accuracy even after millions of alternating load cycles without clearance expansion;

 

Micron-level spherical treatment on roller end faces with flexible pocket cage design—NMT's unique process for rolling consistency in crossed roller bearings uses flexible pocket structures enabling smooth re-establishment of contact during direction changes rather than sudden impact, effectively suppressing torque fluctuations;

 

Group matching of rollers with micron-level dimensional tolerance control, compressing出厂 clearance dispersion to an extremely narrow range;

 

Assembly in temperature-controlled dust-free workshops with four full inspections before delivery: load test, temperature rise test, clearance test and rotational accuracy test;

 

High-purity bearing steel with thorough stabilisation treatment, preventing material翘曲 from residual stress release during long-term service.

 

All dimensions comply with international standards for direct interchange with mainstream crossed roller bearings.

 

6. Precision Grades & Customisation Options

P5 Grade: General precision grade, suitable for most industrial robot joints and automation turntables;

 

P4 Grade: High precision grade, suitable for CNC machine tool turntables, precision testing equipment and optical instruments;

 

P2 Grade: Ultra-high precision grade, suitable for semiconductor equipment, aerospace-grade precision rotation mechanisms and high-end medical imaging equipment.

 

Customisation options: special clearance configurations, high/low temperature resistant materials, special grease adaptation, non-standard sizes, integrated locating taper design, etc.

 

7. Wide Application Fields

Industrial Robots: Bases, shoulders, elbows, wrists, finger joints—providing high-rigidity compact support;

CNC Machine Tools: Rotary tables, indexing plates, vertical grinder worktables, precision rotary worktables;

Medical Equipment: CT scanner slip ring systems, surgical robot bases, rehabilitation equipment rotary platforms;

Semiconductor Equipment: Wafer handling robots, vacuum transfer chambers, IC manufacturing equipment rotary platforms;

Precision Testing Equipment: Precision test turntables, optical telescopes, large radar antennas;

Laser Processing Equipment: Laser cutting machine turntables, LiDAR scanning mechanisms;

Aerospace: Satellite antenna azimuth drives, missile launcher slewing devices;

General Machinery: DD motors, robotic rotating sections, precision alignment platforms.

 

8. Brand Supply & Customisation Service

NMT maintains sufficient spot inventory of mainstream crossed roller bearing specifications for urgent equipment repair and mass complete machine supporting with short lead time. Customisation services include P4/P2 high precision grades, special clearance, high/low temperature resistant materials, special grease, non-standard sizes, integrated locating taper design, etc. Professional engineers provide targeted selection schemes based on equipment load spectrum, installation space, accuracy requirements and speed range to optimise bearing configuration and structural selection, improve overall machine rigidity, control end-effector jitter, extend precision retention cycles and cut the overall life cycle cost of equipment.