Various rotating equipment subject to combined loads——industrial robot bases and wrists, crane slewing mechanisms, radar antenna turntables, medical equipment rotary platforms and CNC rotary tables——are subjected to axial loads, radial loads and tilting moments simultaneously during operation. Installation space is often limited and compact, requiring bearings to provide high rigidity and high rotational accuracy within the smallest possible cross-section. Conventional bearing structures often require multiple bearing sets in combination under combined loads——thrust bearings for axial forces and radial bearings for radial forces——which significantly increases axial dimensions and structural complexity.

Most precision rotating equipment requires long-term continuous operation, placing extremely high demands on bearing life and reliability. Frequent start-stop cycles and changing load directions require bearings with stable operational performance and impact resistance. The industry urgently requires bearings that can simultaneously withstand bidirectional axial loads, radial loads and tilting moments within compact spaces.

NMT Four-Point Contact Ball Bearings employ a unique Gothic arch raceway design, enabling a single bearing to simultaneously withstand radial loads, bidirectional axial loads and tilting moments. Under no load or pure radial load, the balls contact both inner and outer ring raceways at four points; under pure axial load, the contact transitions to two-point contact, combining the functions of both single-row and double-row angular contact ball bearings-



. Four-point contact ball bearings are a separable radial single-row angular contact ball bearing type, primarily applied in engines, hoisting machinery, robots and other high axial load applications-



.

Compared to double-row bearings, four-point contact ball bearings offer advantages of smaller axial space, higher limiting speed and smaller axial clearance, with separable structure for convenient installation-



. Through unique ball path geometry that produces twice as many contact points, the bearings can resist radial, thrust and moment loads individually or in any combination-



. More balls can be incorporated in the bearing to achieve higher load capacity-



.

Rolling elements are precision-machined from high-purity bearing alloy steel, subject to strict micron-level dimensional sorting, with surfaces superfinished. Inner and outer rings undergo forging, precision grinding and superfinishing. All components receive quenching heat treatment and long-term low-temperature stabilization processing to achieve sufficient surface hardness with core toughness, balancing wear resistance and impact resistance. High-precision cages accurately guide rolling elements for smooth, low-noise operation. Products are available in multiple precision grades, suited to different speed and accuracy requirements.

Products adopt international standard dimensions with excellent interchangeability. Comprehensive specifications cover bore diameters from 16mm to over 650mm, with speed ranges from 1500 to 17000 r/min-



, widely applied to industrial robot bases and wrists, crane slewing mechanisms, radar antenna turntables, medical equipment rotary platforms, CNC rotary tables and various combined-load precision equipment. The bearings adapt to continuous rotation, frequent start-stop and varying load direction conditions.

Core Product Advantages

1. Unique Gothic arch raceway design enables a single bearing to simultaneously withstand bidirectional axial loads, radial loads and tilting moments, with one bearing replacing multiple combinations;

2. Four-point contact under no load or pure radial load, transitioning to two-point contact under pure axial load, combining the functions of both single-row and double-row angular contact bearings;

3. Smaller axial space, higher limiting speed and smaller axial clearance compared to double-row bearings, adapting to compact spaces and high-speed conditions-



;

4. Separable structure enables convenient installation and maintenance, and can be combined with cylindrical roller bearings for optimized lubrication-



;

5. Accommodates more balls for higher load capacity-



;

6. Precision heat treatment across all components provides high surface hardness with good core toughness, resisting wear and impact;

7. Superfinished raceways matched with graded rolling elements deliver low friction torque and minimal temperature rise for long-term continuous operation;

8. High-precision cages accurately guide motion for smooth, reliable operation and extended bearing service life;

9. Standard external dimensions ensure great interchangeability to replace imported counterparts and lower procurement costs.

Typical Application Scenarios

Industrial robot bases and wrist joints; Crane slewing mechanisms and boom supports; Radar antenna turntables and missile launcher slewing devices-



; Medical equipment rotary platforms (CT, linear accelerators); CNC rotary tables and indexing plates; Port machinery and marine machinery slewing supports; Construction machinery slewing platforms; Aerospace ground equipment turntables.

Quality Assurance

NMT Four-Point Contact Ball Bearings are manufactured with premium refined bearing alloy steel. Incoming inspection includes chemical composition testing and metallurgical sampling inspection to eliminate material defects at source. Rolling element blanks are precision-machined, followed by sequential rough grinding, finish grinding and superfinishing with strict control over sphericity error and surface roughness. Stress relief annealing is conducted after rough machining of inner and outer ring forgings to eliminate internal stress, followed by quenching and low-temperature stabilization treatment to reduce dimensional variation risks under long-term combined loads.

All rolling elements pass flaw detection screening to remove parts with cracks and dents. All components go through high-pressure cleaning and dust-free drying before assembly in clean workshops. Appropriate grease is filled according to practical operating conditions. After assembly, finished bearings undergo combined load endurance testing, rotational accuracy inspection, friction torque testing and temperature rise testing. All unqualified products are eliminated completely to guarantee stable and consistent performance of bulk goods and supply reliable four-point contact ball bearing solutions for combined-load precision equipment.

Product Range

Four-point contact ball bearing standard series (thin-section series, heavy-duty series); Bore diameters from 16mm to over 650mm; Speed range 1500 to 17000 r/min-



; Open and sealed options available.

Brand Strength

NMT focuses on R&D and manufacturing of precision four-point contact ball bearings. Targeting common industry challenges of combined loads, compact spaces and precision retention in industrial robots, cranes, radar turntables and medical equipment, NMT continuously optimizes Gothic arch raceway cross-section design, steel ball materials and heat treatment technology. The bearings effectively solve common problems of conventional multi-bearing combinations such as complex structure occupying space and insufficient single-bearing load capacity. NMT products reduce risks of bearing failure on precision equipment, improve long-term operational stability and reliability, and support stable continuous operation of various combined-load precision devices.