Angular contact ball bearings feature a fixed contact angle between rolling elements and raceways, capable of bearing combined radial load and unidirectional axial load simultaneously. Bidirectional axial positioning is realized through combined assembly of multiple bearings to adapt to high-speed rotation, precision positioning and continuous axial thrust conditions. Classified by contact angle: C (15°), AC (25°), B (40°). Small contact angles prioritize ultimate high-speed operation, while large contact angles enhance axial load capacity. They are commonly combined in three pairing modes: DB back-to-back, DF face-to-face, DT tandem, serving as core precision supporting parts for CNC lathe spindles, machining center spindles, screw air compressors, centrifugal water pumps, high-speed gearbox shafts and high-speed motors.

Main model classification: 7000 ultra-light thin precision series, 7200 general main series, 7300 thickened heavy-duty axial force series. Precision grades: P0 general grade, P6, P5, P4, P2 ultra-precision spindle grade. Sealing types: open type without seal, double rubber seal 2RS, metal shield Z. Mounting pairing: DB back-to-back, DF face-to-face, DT tandem pairing.

Compared with deep groove ball bearings, they provide axial load capacity to restrict shaft play for high-speed rotating shafts with axial pressure. Versus tapered roller bearings, they achieve much higher limiting speed and rotational accuracy to meet high-precision cutting requirements of machine tools. The main drawback is inability to bear bidirectional axial force independently; paired assembly is mandatory with strict requirements for preload, coaxiality and lubrication cleanliness.

CNC machining centers, screw air compressors and high-pressure centrifugal pumps operate continuously under high-speed rotation, high-temperature grease deterioration, cutting fluid moisture intrusion and alternating gear axial thrust. Inferior angular contact ball bearings suffer poor roundness of steel balls and rough grinding texture on inner & outer raceways, leading to excessive vibration at high speed, large spindle runout, textured workpiece surfaces and dimensional tolerance overshoot. Substandard internal cleanliness causes pitting spalling on raceways from tiny impurities under high speed, triggering rapid temperature rise and abnormal noise. Deviated contact angle forming leads to uneven preload distribution after pairing, resulting in unilateral overheating and seizure. Lack of effective protective seals causes rust on steel balls and raceways from moisture, directly scrapping high-speed spindle precision, seizing air compressor main units and halting production lines with heavy costs for defective products and major equipment overhaul.

NMT angular contact ball bearings cover full-size specifications of 70, 72 and 73, mass-produced from P0 general industrial grade to P4 & P2 ultra-precision machine tool spindle grade. Manufactured with high-purity vacuum-degassed bearing steel, integral quenching plus low-temperature stabilizing aging suppress thermal deformation under high-speed temperature rise. G3/G5 high-precision steel balls are adopted; mirror superfinishing on raceways delivers ultra-low surface roughness to drastically reduce heat generation from high-speed friction. Mold forming for contact angles ensures high consistency within batches for controllable and uniform preload after paired assembly. Multiple structures available: open type, double-sided rubber seal and metal dust cover. Fluororubber seals resist oil & water erosion. Fully compliant with national standard dimensions for direct replacement of imported and domestic precision spindle bearings for spindle overhaul of machine tools, assembly of air compressor main units and renovation of high-speed pump equipment.

High-end CNC machine tools, permanent-magnet high-speed air compressors and high-pressure chemical pumps are upgraded toward ultra-high rotational speed, micron-level rotational accuracy and long-life maintenance-free operation. Conventional angular contact ball bearings feature insufficient precision grade, rough raceway machining, poor internal cleanliness and weak medium-resistant sealing, leading to severe heat generation & vibration, rapid precision attenuation and moisture rust failure at high speed. They fail to satisfy requirements of high-precision cutting of 5-axis machining centers, 24-hour continuous high-speed gas production of screw compressors and sealed medium operation of chemical pumps. The market demands angular contact ball bearings with high precision, low heat generation and long-term high cleanliness.

Micron-level roundness tolerance control for NMT precision steel balls and mirror superfinishing on raceways form a stable oil film layer to prevent grease film rupture under high-speed rotation for outstanding temperature control. Preload calibration is completed before delivery for direct installation of DB/DF/DT combinations without on-site grinding shim adjustment. Ultra-precision models undergo thermal cycle stabilization treatment to avoid spindle precision drift under temperature variation. Fluororubber contact seals block cutting fluid, condensed water and compressed oil vapor from entering bearing cavities. Strict control of retained austenite in raw materials ensures excellent dimensional stability during long-term high-speed operation to eliminate spindle precision deviation from thermal deformation.

All finished bearings pass roundness inspection, high-speed temperature rise bench test, vibration classification detection and water vapor sealing aging test to eliminate defective products with inaccurate precision, abnormal heat generation and unqualified cleanliness, guaranteeing long-term high-precision stable operation of high-speed precision rotating components.

Core Product Advantages

Fixed contact angle structure bears combined radial and unidirectional axial loads; combined assembly locks bidirectional axial play for accurate spindle positioning.

Multiple contact angle options: 15° high-speed type, 25° general type, 40° heavy axial load type to match diverse thrust and speed demands.

Full coverage of precision grades: P4/P2 high-precision for precision machining of machine tool spindles, general grade for transmission of air compressors and pumps.

High-precision steel balls + mirror raceways reduce friction loss and temperature rise at high speed with low spindle vibration for stable machining accuracy.

Pre-paired calibration before delivery enables direct assembly of back-to-back, face-to-face and tandem combinations to cut on-site assembly & commissioning working hours.

Optional fluororubber seals resist corrosion from cutting fluid, lubricating oil and condensed water for humid, oil-gas working conditions.

Stabilization heat treatment prevents dimensional deformation under high-speed high-temperature for excellent long-term precision retention.

Universal standard outer dimensions enable direct interchange with original bearings for machine tools, air compressors and high-speed pumps.

Typical Application Scenarios

Precision spindle bearings for CNC machining centers, lathes, grinders and engraving machines; high-speed rotor bearings for screw air compressors and scroll air compressors; main shaft bearings for high-pressure centrifugal pumps, chemical process pumps and boiler feed water pumps; support bearings for high-speed gearboxes, servo motors and high-speed fan main shafts; core bearings for textile high-speed spindles, centrifuges and refrigeration compressors; high-speed precision support bearings for robot joints.

Quality Assurance

NMT angular contact ball bearings adopt vacuum remelted bearing steel with ultra-low impurity content to extend contact fatigue life. Superfinishing on inner & outer ring raceways delivers high profile conformity for even stress distribution. Precision steel balls are sorted and matched to ensure smooth rotation of complete bearings. Precision-grade bearings undergo low-temperature aging stress relief to eliminate machining internal stress and restrain high-speed thermal deformation. Seal models adapt to two spindle lubrication schemes: oil-air lubrication and grease lubrication. Clearance grouping marking is finished before delivery for convenient pairing selection and assembly. Fully applicable to high-speed rotation, precision positioning, alternating axial thrust and humid oil-gas environments.

Product Range

7000 ultra-thin series, 7200 general series, 7300 heavy axial load series; contact angle C(15°)/AC(25°)/B(40°); precision P0/P6/P5/P4/P2; open type, single-side metal shield Z, double-sided rubber seal 2RS; DB back-to-back, DF face-to-face, DT tandem paired bearings.

Brand Strength

NMT Japan addresses four typical defects of traditional angular contact ball bearings: excessive heat & vibration from rough raceways, unbalanced bearing force caused by contact angle deviation, early pitting corrosion from internal impurities and moisture rust from poor sealing. Process upgrades including mirror superfinishing of raceways, high-precision steel ball matching, factory pre-pairing and medium-resistant sealing improve bearing performance of low temperature rise, low vibration and long-lasting high precision. We supply precision high-speed bearings for OEMs, machine tool repair shops, air compressor maintenance service providers and pump manufacturers to reduce defective machining dimensions of machine tools, high-temperature shutdown of air compressors and abnormal noise faults of high-speed pumps, cutting maintenance frequency and precision repair costs of precision equipment.