I. About NMT

Japan NMT is a brand dedicated to the R&D and manufacturing of precision bearings. As precision machinery and automation equipment continue to advance toward higher speeds, greater precision and heavier loads, NMT embraces "systematic precision engineering" as its core philosophy, integrating cutting-edge technologies in materials science, precision machining and tribology into bearing design and manufacturing. The product line covers crossed roller bearings, thin-section bearings, angular contact ball bearings, deep groove ball bearings, thrust cylindrical roller bearings and other full-series products, widely applied in industrial robots, machine tool spindles, precision instruments, medical equipment and semiconductor manufacturing equipment.

 

II. Product Introduction

In robot joint design, engineers often face a dilemma: increasing bearing size to ensure load rigidity, yet thereby compressing the hollow space for cabling and limiting end-effector integration. NMT Crossed Roller Bearings break this deadlock.

 

By arranging cylindrical rollers at 90°交错 on a compact rolling circumference, NMT achieves simultaneous support for radial loads, axial loads and tilting moments within an extremely small cross-sectional height. This means robot wrists or positioners no longer need multiple bearing sets stacked to share forces——a single NMT crossed roller bearing handles it all. The axial space saved can be allocated to cables, tubing or even force-torque sensors, giving the robot本体 greater end-integration capability while maintaining high rigidity.

 

In actual robot operation, precision motion depends on strict management of "clearance." Conventional bearings must预留 certain clearance for smooth assembly, but this tiny gap is magnified into significant positioning deviation at the robot end by arm length. NMT's approach is to implement negative clearance preload during manufacturing——precision grinding of inner and outer rings enables rollers to operate with zero clearance or even微量 interference. This preload is not achieved through hard elastic deformation, but based on NMT's precise calculation of raceway profiles and roller crowning, ensuring friction torque fluctuation throughout the entire rotation cycle is controlled within an extremely narrow range. For industrial robots that need to repeatedly execute the same point for welding or assembly, this means every positioning movement reproduces the same posture without random angular drift.

 

In the trend toward lightweight and compact collaborative robots, the mass and inertia of bearings themselves are receiving unprecedented attention. NMT has responded by performing topology optimization on non-load-bearing areas of crossed roller bearings while maintaining raceway load capacity. This optimization is not simply thinning walls, but identifying critical stress paths through finite element analysis, retaining necessary rib structures while removing material that contributes little to rigidity. The result is a series of bearing models with significantly reduced weight but no sacrificed rigidity. When these lightweight bearings are installed in robot joints, the reduction in overall自重 directly translates into higher payload-to-weight ratios and lower motor energy consumption, particularly suitable for weight-sensitive mobile robots and exoskeleton devices.

 

NMT's brand philosophy includes a dimension that is easily overlooked but critically important: respect for application scenario boundaries. Different robots have fundamentally different requirements for rotational smoothness——precision assembly robots need moderate damping to absorb micro-impacts, while high-speed sorting robots pursue极致 low friction for rapid response. NMT therefore does not provide one-size-fits-all lubrication solutions. Its crossed roller bearing standard models reserve接口 adaptability for changing grease according to different operating conditions, while sealing structures offer multiple options including non-contact labyrinth seals and contact rubber seals. This restrained yet flexible design approach enables NMT crossed roller bearings to adapt to a wide range of scenarios from cleanrooms to foundry and grinding workshops without major structural modifications, truly becoming a universal precision joint in the hands of robot engineers.

 

III. Core Technologies

Orthogonal Dense Roller Arrangement

 

The core of NMT crossed roller bearings lies in their unique orthogonal dense arrangement of cylindrical rollers. Rollers are arranged at 90°交错 on a compact rolling circumference, upgrading contact from point to line, achieving simultaneous support for radial loads, axial loads and tilting moments within an extremely small cross-sectional height. This design enables the bearing to provide maximum support rigidity with minimum volume.

 

Negative Clearance Preload Technology

 

The clearance in conventional bearings is magnified into significant positioning deviation at the robot end by arm length. NMT precision-grinds inner and outer rings to enable rollers to operate with zero clearance or even微量 interference, ensuring friction torque fluctuation throughout the entire rotation cycle is controlled within an extremely narrow range. For industrial robots that repeatedly execute the same point operations, this means every positioning movement reproduces the same posture without random angular drift.

 

Topology Optimization Lightweight Design

 

While maintaining raceway load capacity, NMT identifies critical stress paths through finite element analysis, performing topology optimization on non-load-bearing areas and removing material that contributes little to rigidity. The reduction in overall自重 directly translates into higher payload-to-weight ratios and lower motor energy consumption.

 

Scenario-Adaptive Flexible Design

 

NMT crossed roller bearings reserve接口 adaptability for changing grease according to different operating conditions, with sealing structures offering multiple options including non-contact labyrinth seals and contact rubber seals. From cleanrooms to foundry and grinding workshops, NMT crossed roller bearings adapt to a wide range of application scenarios.

 

IV. Typical Application Scenarios

Industrial Robot Wrists and Positioners: NMT crossed roller bearings simultaneously carry radial, axial and tilting moments with a single bearing, saving axial space for cables, tubing and force-torque sensors.

 

Precision Assembly Robots: Require moderate damping to absorb micro-impacts; NMT crossed roller bearings meet this need through flexible lubrication solutions.

 

High-Speed Sorting Robots: Pursue极致 low friction for rapid response; NMT crossed roller bearings provide low-friction lubrication solutions.

 

Collaborative Robots: Lightweight design translates reduced overall自重 into higher payload-to-weight ratios.

 

Mobile Robots and Exoskeleton Devices: Significantly reduced bearing weight directly improves payload-to-weight ratios and lowers motor energy consumption.

 

V. Quality Assurance

Manufacturing precision is the core competency of the NMT brand. Production lines employ fully closed-loop controlled ultra-precision grinding systems equipped with nanometer-resolution in-process measurement devices that monitor and correct machining parameters in real time, ensuring bearing ring raceway geometry accuracy reaches sub-micron levels. Raceway roundness and waviness are协同 controlled within extremely tight tolerance windows. Each rolling element undergoes multi-spectral screening and surface superfinishing to achieve near-perfect sphericity and mirror-like surface finish.

 

In finished product inspection, each bearing set undergoes rotational accuracy testing, vibration testing, friction torque testing and clearance re-measurement, with all data archived with factory serial numbers. NMT strictly screens the friction torque distribution range of each bearing batch to ensure performance consistency across the batch.

 

Product Range

 

Crossed roller bearing standard series (RA/RB/RE/RU types); Selection based on bore diameter, load rating and precision grade. P5 and P4 precision grades available as options.

 

VI. Brand Strength

Japan NMT focuses on R&D and manufacturing of precision crossed roller bearings. Targeting common industry challenges of combined loads, compact spaces and long-term precision retention in industrial robots, precision rotary platforms and medical equipment, NMT crossed roller bearings—with orthogonal dense arrangement, negative clearance preload technology and topology optimization lightweight design—effectively solve common problems of ordinary bearings' insufficient rigidity and load capacity, and the precision loss from complex combined bearing assemblies. NMT crossed roller bearings adapt to a wide range of application scenarios without major structural modifications, reducing risks of bearing failure on precision equipment, improving long-term operational stability and reliability, and supporting stable continuous operation of various precision rotating devices.