1 Complete Model, Dimensions, Loads & Technical Parameters

Full Model: 7000 CD/P4A

Model Code Explanation

7000: 70 series standard size for miniature precision spindles; C: 15° classic contact angle balancing high speed and composite rigidity; D: NMT self-developed D-type high-capacity internal geometry for optimized ball track and contact area; P4A: P4A super precision grade with higher accuracy than ordinary P4 bearings. It is a single open basic bearing without factory preload and preset clearance, supporting free on-site matching.

Standard Dimension Parameters

Bore d: 10 mm

Outer diameter D: 26 mm

Width B: 8 mm

Contact angle: 15°

Load Performance Data

Basic dynamic load rating Cr: 4.1 kN

Basic static load rating C0r: 1.66 kN

Limit Speed Reference

Grease lubrication: 75000 r/min

Oil-air lubrication: 110000 r/min

Boundary Installation Dimensions

Inner ring large end shoulder diameter: 15.1 mm

Outer ring large end shoulder diameter: 20.9 mm

Min chamfer r₁,₂: 0.3 mm

Min chamfer r₃,₄: 0.2 mm

Full Product Attributes

Contact style: standard two-point contact

Row: single row

Race structure: integral seamless one-piece inner and outer ring

Internal design: NMT D-type high-capacity structure

Matching feature: single unit without preset clearance and preload

Matching layout: back-to-back, face-to-face, tandem optional

Precision class: P4A super precision

Material: high-purity bearing steel

Coating: uncoated

Seal: open seal-free structure

Pre-filled lubricant: none, fully customizable lubrication

Speed note: Actual speed is affected by lubrication, preload, assembly accuracy and load. Contact NMT for professional working condition parameters.

2 Structure & Operating Characteristics

NMT 7000 CD/P4A is a P4A super precision single angular contact bearing specially developed for miniature high-speed precision rotary equipment. Adopting mature 70-series structure and self-developed D-type high-capacity internal design, it solves the shortcomings of weak rigidity, low load capacity and unstable temperature rise of traditional miniature precision bearings, serving as the core accessory for small engraving spindles, PCB drilling spindles and high-speed precision motors.

The classic 15° contact angle balances ultimate speed and composite load resistance perfectly. It features uniform rolling friction, low centrifugal force deviation and minimal shaft runout during high-speed operation, maintaining micron-level rotary accuracy for long-term continuous operation with stable temperature rise and low vibration.

The integral seamless one-piece race eliminates structural splicing defects, providing uniform rigidity and excellent resistance to overturning moment, alternating load and impact deformation. All bearings undergo stabilized heat treatment and mirror raceway superfinishing, with dimensional deviation strictly controlled within P4A super precision standards and high batch consistency.

The open grease-free and seal-free design supports diversified lubrication solutions including oil-air ultra-high-speed lubrication and clean grease lubrication. As a universal single basic bearing without fixed preload and matching mode, it provides high design flexibility to adapt to various miniature spindle structures and working condition requirements.

3 Core Performance Advantages

1. P4A Super Precision Stability: Micron-level dimensional and rotational accuracy reduces spindle runout and machining error, improving workpiece surface finish and precision for high-end finishing scenarios.

2. D-Type High-Capacity Design: Optimized internal structure enhances dynamic and static load capacity within compact size, achieving higher rigidity and more stable load resistance than ordinary bearings of the same specification.

3. 15° Balanced Contact Angle: Excellent high-speed performance with balanced speed and rigidity, featuring low vibration, low noise and stable temperature rise under light and medium high-speed loads.

4. Integral High-Rigidity Structure: Seamless one-piece forming ensures uniform structural strength, resisting start-stop impact and alternating deformation for longer service life and stable precision.

5. Universal Free Matching: Three mainstream assembly layouts optional, flexibly adapting to anti-overturning, high-positioning and high-axial-load working conditions with strong universality and low inventory cost.

6. Flexible Open Lubrication: No seal or pre-filled grease, fully compatible with various lubrication processes such as high-speed oil-air lubrication and clean grease lubrication.

7. Pure Uncoated Structure: High-purity bearing steel avoids raceway contamination caused by coating peeling, providing good compatibility with various lubricants and stable long-term operation.

4 Typical Application Scenarios

4.1 Miniature Precision Machine Tool Spindles: Small high-speed engraving and milling spindles, PCB micro drilling spindles, miniature internal grinding heads, small CNC precision rotary spindle units.

4.2 High-Speed Mini Drive Motors: Precision servo micro motors, high-speed engraving spindle motors, built-in high-speed rotary motors for testing equipment, variable-frequency precision drive motors.

4.3 Precision Testing & Laboratory Instruments: High-precision visual alignment platforms, small precision dividing heads, micro rotary test jigs, laboratory precision dimension inspection equipment.

4.4 Small Automatic Precision Transmission Modules: Precision rotary shafts for electronic component processing, precision rotary transfer mechanisms, small cam rotary units, automatic tooling precision rotary stations.

4.5 Electronic & Light Industry Precision Equipment: Small mold finishing equipment, precision textile micro shafts, packaging automation precision rotary mechanisms, core rotary components of small precision automation equipment.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A super precision bearings must be assembled in a dust-free and constant-temperature clean environment. Thoroughly remove dust, oil stains and metal debris from all mating surfaces to avoid precision degradation and raceway wear. Low-temperature thermal mounting is recommended. Direct striking on bearing working surfaces is prohibited to prevent permanent indentation damage. Strictly control fitting interference to avoid rotation jamming and abnormal temperature rise. Use bearings from the same batch for combined assembly to ensure consistency and stability.

5.2 Matching Layout & Preload Instructions

This single bearing has no factory preset clearance or preload, and preload & clearance are fully controlled by on-site spacers. Back-to-back layout provides excellent anti-overturning rigidity for overhanging spindle and offset load conditions; face-to-face layout ensures uniform stress and ultra-high positioning accuracy for precision drilling and detection; tandem layout greatly improves axial load capacity for unidirectional heavy axial loads. Light preload is recommended for high-speed precision working conditions to prevent excessive temperature rise and thermal deformation.

5.3 Lubrication Matching Solutions

No pre-filled lubricant inside the bearing. Oil-air circulating lubrication is preferred for ultra-high speed conditions to release the maximum speed performance of 110000 r/min and control temperature rise effectively. Low-volatility high-cleanliness special spindle grease is suitable for medium-low speed finishing and dust-free clean workshops. Mixing different lubricants is forbidden. Completely clean residual grease before replacement to avoid lubrication failure and abnormal raceway wear.

5.4 Speed Parameter Note

The marked limit speeds are standard working condition reference values. Actual operating speed is dynamically affected by lubrication mode, assembly coaxiality, preload, continuous load and ambient temperature, and needs to be reduced appropriately under heavy load and high preload conditions. Consult NMT professional technicians for accurate working condition speed and technical solutions.

6 Daily Maintenance & Fault Troubleshooting

Monitor bearing noise, vibration and temperature rise during no-load trial operation to prevent precision deviation caused by thermal deformation. The open seal-free structure requires external protective measures to block dust, cutting fluid and metal debris and avoid raceway pitting and jamming.

Implement regular lubrication replenishment and replacement to maintain stable oil film on rolling surfaces. Abnormal noise, precision drift, intensified vibration and overheating are mainly caused by insufficient lubrication, assembly coaxial deviation and foreign matter intrusion. Avoid long-term overload and impact load operation to prevent permanent raceway deformation and ensure long-term stable precision operation of equipment.