Rotary platforms of construction machinery, industrial robot joints, automated turnover tooling and radar rotary bases bear radial loads, bidirectional axial loads and large overturning moments simultaneously during operation, belonging to multi-dimensional combined load conditions. Ordinary single-row bearings can only bear loads in a single direction and cannot resist overturning moments independently. Combined assembly of multiple bearings will greatly expand structural volume and fail to meet lightweight and thin-wall design requirements of equipment. Most rotary mechanisms operate mainly in low-speed reciprocating swing mode with frequent start and stop, and load directions keep changing continuously, leading to repeated internal stress conversion of bearings and setting strict standards for raceway structure and contact form.

Many rotary equipment is limited by installation space. The overall design pursues compact thin-wall structure. Components sustain alternating moment loads for a long time, and partial outdoor working conditions face erosion from dust and moisture. Conventional double-row bearings feature thick heavy structures, occupy large space and carry higher procurement costs. Common angular contact bearings only withstand unidirectional axial force and cannot bear bidirectional thrust and overturning moments independently. Paired installation is mandatory, which increases assembly difficulty. The industry urgently demands four-point contact ball bearings that can bear multi-directional combined loads in a single unit and adapt to low-speed swing scenarios for various rotary transmission devices.

NMT Precision Four-Point Contact Ball Bearings adopt specially designed single curved raceways. Four-point contact forms between steel balls and raceways. A single bearing unit can bear radial loads, bidirectional axial loads and overturning moments at the same time, simplifying the whole rotary support structure. Models without separators own more compact structure suitable for thin-wall rotary units. Versions equipped with cages reduce mutual friction of steel balls and adapt to frequent swing working conditions. The unique contact structure effectively disperses concentrated stress generated by torque, inhibits local pitting corrosion of raceways and greatly extends service life under alternating loads.

Inner and outer rings are forged from high-purity bearing alloy steel and processed through multiple precision grinding and superfinishing to achieve accurate and smooth raceway profiles. All components receive complete quenching treatment and long-time low-temperature stabilization treatment to guarantee sufficient surface hardness and matrix toughness with excellent fatigue resistance and impact resistance. Steel balls are sorted at micron level with high dimensional consistency to realize uniform force distribution during swing operation. Split cages separate steel balls accurately to avoid collision and abrasion between rolling elements and reserve lubrication space to keep grease attached to contact areas continuously.

The bearings adopt standardized specifications with excellent interchangeability, widely applied to rotary mechanisms of construction machinery, intelligent robot joints, automated turnover equipment and precision medical rotary platforms. Adaptable to multiple operation modes including low-speed continuous rotation, reciprocating swing and frequent start-stop.

Core Product Advantages

Four-point contact raceway structure enables single bearing to bear radial force, bidirectional axial force and overturning moments simultaneously and simplify support structure;

Compact thin-wall structural design saves installation space effectively and supports lightweight and miniaturized upgrading of machinery;

Capable of low-speed continuous rotation and reciprocating swing, perfectly matching working demands of robot joints and rotary platforms;

Precision superfinished raceways matched with graded steel balls deliver outstanding stress dispersion effect and slow surface fatigue damage caused by alternating torque;

Multiple structural options: uncaged models own stronger load capacity, caged versions feature lower friction to adapt to diverse working conditions;

Standardized heat treatment for all components provides excellent pitting and fatigue resistance and stable performance under dusty and humid environments;

Optimized internal lubrication space extends grease service cycle and reduces equipment shutdown maintenance frequency;

Standard universal dimensions enable convenient assembly and cut spare part procurement and overall manufacturing costs of rotary equipment.

Typical Application Scenarios

Rotary support mechanisms of excavators, cranes and other construction machinery; multi-degree-of-freedom industrial robots and collaborative robot joint units; turnover tooling and rotary fixtures on automated production lines; rotary bases for radar and monitoring equipment; rotary platforms of precision medical equipment; light wind power steering mechanisms and small automated rotary worktables.

Quality Assurance

NMT Precision Four-Point Contact Ball Bearings are manufactured with premium refined bearing alloy steel. Incoming inspection includes chemical composition testing and metallurgical sampling to eliminate material defects at source. Inner and outer ring blanks adopt precision forging technology to optimize metal flow lines and enhance overall structural strength. Stress relief annealing is carried out after rough machining to remove internal processing stress, followed by quenching and low-temperature stabilization treatment to reduce dimensional variation risks under long-term alternating torque.

Raceways go through rough grinding, finish grinding and superfinishing with strict control over curved profile precision and surface roughness. All steel balls pass flaw detection screening to remove workpieces with cracks and dents. All components undergo high-pressure cleaning and dust-free drying before assembly in clean workshops. Appropriate grease is filled according to service conditions. After assembly, finished bearings receive combined torque endurance testing, reciprocating swing simulation testing and temperature rise inspection. All nonconforming products are eliminated completely to guarantee consistent performance of bulk goods and supply reliable support solutions for all types of rotary transmission equipment.

Product Range

Caged four-point contact ball bearings, uncaged four-point contact ball bearings. Selection depends on load magnitude, operation mode and installation space.

Brand Strength

NMT focuses on R&D and manufacturing of rotary precision bearings. Targeting common challenges of multi-directional combined loads, low-speed reciprocating swing and alternating overturning moments existing in rotary mechanisms of construction machinery and industrial robots, NMT continuously optimizes raceway structure, contact angle and heat treatment technology. The bearings effectively solve industry difficulties such as incapability of ordinary bearings to bear overturning moments independently, bulky structure of multi-bearing combinations and fatigue peeling caused by frequent swing. NMT products lower failure risks of intelligent equipment and construction machinery and ensure long-term stable operation of all rotary devices.