Angular contact ball bearings adopt inclined raceway contact angle structure to bear radial load and unidirectional axial load simultaneously. They must be installed in matched arrangements including back-to-back (DB), face-to-face (DF) and tandem (DT) to limit axial movement of spindles effectively, featuring superior rigidity, high-speed performance and positioning accuracy compared with deep groove ball bearings, serving as core positioning bearings for precision machine tool spindles, screw air compressors, high-speed gearboxes, pump spindles and high-speed spinning equipment. Classic contact angles include 15°(C), 25°(AC) and 40°(B): small contact angles realize high speed and low heat generation, while large contact angles provide strong axial load limit capacity.

Compared with deep groove ball bearings, angular contact ball bearings deliver strong axial rigidity and accurate axial positioning for spindles requiring tight axial clearance control. Different from cylindrical roller bearings, they operate more smoothly with higher limiting speed for high-speed precision machining. The disadvantage is that they cannot work independently and must be installed in pairs with precise preload control, leading to low cost performance under pure radial light-load conditions.

Spindles of CNC lathes, machining centers and rotors of screw air compressors run at high speed continuously under alternating radial-axial combined loads. Excessive axial play of spindles causes dimensional deviation of machined workpieces and rotor friction seizure inside air compressors. Conventional angular contact ball bearings suffer from large contact angle error, low-precision steel balls, no factory matching and unstable heat treatment, resulting in excessive temperature rise, rapid axial clearance enlargement, sharp vibration noise and bearing seizure during high-speed operation, causing workpiece scrap for machine tools and major overhaul of air compressor main units with high maintenance and shutdown losses.

NMT angular contact ball bearings cover full 7000,7200,7300,7400 series with complete C(15°), AC(25°), B(40°) contact angles, factory pre-matched in DF, DB, DT arrangements. Open type and 2RS rubber seal are available, with solid brass cages and nylon cages optional. Standard and C3 clearance, P0/P6/P5/P4 high spindle precision grades adopt international standard dimensions for direct replacement of imported precision angular contact bearings for precision machine tools, air compressors and high-speed transmission equipment.

With the upgrading of CNC equipment toward ultra-high speed, high precision and long maintenance-free service life, and the demand for continuous trouble-free operation of air compressor mainframes, ordinary angular contact bearings have poor matching accuracy, weak high-speed thermal stability and fast axial rigidity attenuation, failing to meet long-term operation requirements of precision machining and heavy-duty air compressors. The market demands high-end angular contact ball bearings with factory precision matching and low temperature rise at high speed.

NMT adopts one-step precision grinding for raceway contact angles to minimize angular error and ensure uniform force on steel balls. G3/G5 ultra-precision steel balls with micron-level dimensional grouping restrain high-speed runout. Solid brass cages provide high strength to resist high-speed centrifugal force and impact; nylon cages optimize lubrication flow to reduce noise and temperature. All matched bearings complete pre-matching inspection before delivery with unified axial preload margin for direct installation without secondary on-site finishing.

High-purity bearing steel with low-temperature stabilizing heat treatment reduces thermal deformation at high speed. P4/P5 high-precision spindle bearings are sorted by dimension and end face parallelism to restrict spindle end face runout to an extremely small range. Heavy-duty air compressor versions adopt 40° large contact angle to strengthen axial thrust resistance and counteract gas axial thrust of rotors to avoid unilateral wear of bearings.

All finished bearings pass high-speed temperature rise test, axial rigidity inspection, matched clearance calibration and vibration noise grading inspection to eliminate defective products with angle deviation, unbalanced matching and poor precision. Matched bearings feature excellent coaxiality, small deformation at high speed and stable axial positioning.

Core Product Advantages

Inclined contact angle structure bears combined radial and unidirectional axial load; paired installation achieves bidirectional axial locking to strictly control spindle axial play.

Multiple contact angle options: 15° for extreme high speed, 40° for heavy axial load, covering precision spindle and air compressor core working conditions.

Factory precision matching (DB/DF/DT) eliminates on-site grinding work and shortens equipment assembly time.

Ultra-precision steel balls and precise raceway angle grinding reduce vibration and temperature rise at high speed to prevent spindle precision drift during long service.

Two cage options: brass cage for impact resistance and durability, nylon cage for noise reduction and heat dissipation.

Optional P4/P5 high precision grades meet high-precision positioning requirements of CNC spindles.

Stabilizing heat treatment inhibits thermal deformation to avoid excessive clearance expansion after long high-speed operation.

Universal standard dimensions support direct replacement of imported bearings for easy equipment renovation.

Typical Application Scenarios

Precision spindles of machining centers, CNC lathes and grinders; rotor support for screw air compressor main units; high-speed gearboxes, turbochargers and high-pressure pump spindles; high-speed spinning spindles, centrifuges and precision testing instrument shafts; hydraulic pumps of construction machinery and positioning for high-speed fan transmission shafts.

Quality Assurance

NMT implements full-process precision control for angular contact ball bearings: strict control of oxygen content in bearing steel raw materials, double stress relief annealing after forging; rough forming grinding and mirror superfinishing for inner/outer raceways and angle surfaces; precision grade sorting for steel balls; paired inspection of axial clearance and end face parallelism for matched bearing sets; low-temperature aging treatment for high-precision spindle bearings to stabilize dimensions; dynamic high-speed aging test and axial load durability test for finished products. Delivered matched bearings feature uniform rigidity and stable precision to guarantee machining accuracy of precision equipment and continuous operation stability of air compressors.

Product Range

7000,7200,7300,7400 angular contact ball bearings; C15°/AC25°/B40° contact angles; open type, 2RS rubber seal; solid brass cages, nylon cages; DF/DB/DT matched combination; standard clearance, C3 clearance; P0/P6/P5/P4 precision grades.

Brand Strength

NMT specializes in R&D of precision high-speed bearings. Targeting typical failures including spindle precision loss, unilateral wear of air compressor bearings and high-speed overheating failure, NMT optimizes raceway angle machining, precision matching technology and steel stabilizing heat treatment to greatly improve bearing axial rigidity, high-speed heat resistance and consistency of matched sets. It helps machine tool processing factories stabilize workpiece machining accuracy, reduces overhaul frequency for air compressor manufacturers and cuts economic losses caused by equipment shutdown.