1 Complete Model & Code Explanation

Model: 7013 CDGA/P4A

Code Definition

7013: Basic outer dimension of 70 series light-duty precision angular contact ball bearing

CD: 15° ultra-low contact angle optimized for ultra-high speed, limited axial load capacity, superior limiting speed

GA: One-piece solid brass cage, inner ring guided

P4A: Ultra-precision grade with tight control of runout and dimensional grouping tolerance

Supply form: Supplied as single loose unit, freely combinable into DB/DT matched sets with two or more bearings

Comparative Reference Models

15° all-steel single bearing with GA solid cage: 7013 CDGA/P4A

15° all-steel single bearing with standard turned brass cage: 7013 CD/P4A

15° all-steel DB factory matched set: 7013 CD/P4ADBD

15° all-steel DT factory matched set: 7013 CD/P4ADT

15° hybrid ceramic single bearing with GA cage: 7013 CDGA/HCP4A

Core Basic Dimensions

Bore d: 65 mm

Outer diameter D: 100 mm

Width B: 18 mm

Contact angle: 15°

Structure: Single row open non-sealed single bearing

Rolling element: High-carbon chromium bearing steel standard balls

Ring material: High-carbon chromium bearing steel, ultra-precision mirror grinding on raceway

Cage: GA one-piece solid brass cage (inner ring guided)

Pre-filled lubricant: None

Surface treatment: Mirror finish for rings, high-precision grouped polishing for steel balls, no extra functional coating

Delivery form: Single bearing per package. Factory ground DB/DT matched sets available upon request; preload spacers sold separately

Note: Official dynamic load rating and limiting DN data can be requested from manufacturer.

Full Product Attributes

Contact form: Two-point contact

Number of rows: Single row, single unit

Pairing property: Loose single bearing. Bearings from same batch can be screened on-site for DB/DT matching. Factory pre-matched sets recommended for higher assembly consistency.

Precision class: P4A ultra-precision grade

Material: Inner & outer rings and rolling elements made of high-carbon chromium bearing steel (all-steel bearing)

Seal structure: Open type, non-sealed

Note: CD 15° ultra-low contact angle targets ultra-high-speed light-cutting applications. Compared with split or stamped cages, one-piece solid brass GA cage delivers higher rigidity, less centrifugal deformation under high speed, lower vibration and improved heat dissipation, ideal for spindles running continuously at ultra-high speed. The 15° angle reduces high-speed friction and achieves higher limiting speed than 20°/25° variants but features lower allowable axial load; continuous heavy axial load is prohibited. All-steel construction offers no insulation and is not recommended for built-in motor spindles with shaft current, better suited for belt-driven spindles. It costs less than hybrid ceramic bearings yet generates higher centrifugal heat with lower maximum DN. Open design is exclusively for oil-air lubrication; long-term sealed grease operation is forbidden. For on-site DB/DT assembly, strictly screen face height difference to avoid uneven preload.

2 Structure & Operating Characteristics

Japan NMT 7013 CDGA/P4A is an ultra-high-speed single angular contact bearing of the 7013 series. Inner and outer rings are manufactured from high-carbon chromium bearing steel with stabilized heat treatment and multi-stage aging, plus ultra-precision mirror raceway grinding. Equipped with one-piece solid brass GA cage with inner ring guidance to suppress pocket deformation at high speed. Steel balls undergo high-precision sorting and mirror polishing to reduce rolling friction.

The 15° small contact angle effectively lowers ball spin slip and frictional heat. Solid brass cage provides excellent thermal conductivity for continuous heat removal, suitable for non-stop ultra-high-speed finishing. Disadvantage: heavier all-steel balls lead to lower limiting DN than silicon nitride hybrid bearings. Limited axial capacity means contact ellipse distortion may occur under overload; only for light-load conditions. Supplied as single unit, flexible to configure DB back-to-back or DT tandem layout according to spindle design.

3 Core Performance Advantages

1. CD 15° ultra-high-speed optimized contact angle: Low spin friction at high speed, higher limiting speed than 20°/25° contact angle bearings for prolonged continuous ultra-high-speed finishing.

2. GA one-piece solid brass cage: High structural rigidity, resistant to centrifugal deformation, low vibration and outstanding thermal stability under long-term high-speed operation.

3. All-steel standard rolling element structure: Good ductility and mild impact resistance, obvious cost advantage compared with hybrid ceramic bearings.

4. P4A ultra-precision grade: Strict control of radial and axial runout to maintain stable machining accuracy at high speed.

5. Open non-sealed structure: Eliminates extra friction heat from seal drag, fully compatible with oil-air forced circulation lubrication.

6. Flexible single-unit supply: Supports on-site DB/DT combination to adapt to various spindle support layouts.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A ultra-precision bearings must be assembled in constant-temperature dust-free clean workshops. Remove all burrs and metal debris on shaft and housing mating surfaces. Adopt controlled thermal mounting with limited heating temperature; open flame heating is prohibited. Never strike bearing rings violently to avoid raceway indentation.

For on-site DB/DT matching, use bearings from identical production batch and screen face height tolerance.

5.2 Pairing & Preload Instructions

Supply condition: Single independent bearing without factory matching marks.

Optional layout: Single support, DB back-to-back pair, DT tandem pair.

Recommended preload: Light preload preferred for ultra-high-speed finishing; medium or heavy preload shall be avoided near maximum rotating speed.

Selection reference:

① Built-in motor spindle with shaft current, priority on ultra-low heat →7013 CDGA/HCP4A hybrid ceramic bearing with GA cage

② Belt spindle, continuous ultra-high speed light load, low vibration requirement, cost control →7013 CDGA/P4A all-steel GA single bearing

③ Direct assembly without on-site screening →order factory pre-matched DBD/DTD sets

④ Medium cutting load balancing rigidity and rotational speed →ACE 20° series bearings

5.3 Lubrication Matching Scheme

No pre-filled lubricant. Oil-air forced circulation lubrication is mandatory for continuous ultra-high-speed operation. Special synthetic high-speed spindle grease can only be used temporarily for short commissioning. Install high-precision filter in lubrication circuit to keep oil clean; hard contaminants trigger fatigue spalling on raceways and balls. Do not mix different brands or types of lubricants.

5.4 Speed Parameter Note

Combination of 15° CD contact angle and GA solid cage delivers excellent high-speed performance. Due to heavier all-steel rolling elements, limiting DN is inferior to hybrid ceramic bearings of same size. Complete cooling system and sufficient speed safety margin are required for continuous full-speed operation to prevent axial overload.

6 Daily Maintenance & Fault Troubleshooting

Carry out multi-stage low-speed running-in after assembly. Do not increase speed to rated level until temperature rise and vibration remain stable. Open bearings have no built-in dust shield; reliable dust sealing must be installed on bearing housing.

Maintain continuous supply of clean lubricant to avoid dry friction damage caused by oil starvation. In case of continuous abnormal noise, overheating or sharp vibration increase, inspect sequentially: lubricant cleanliness, preload setting (prevent excessive preload), assembly coaxiality, matching accuracy of bearing faces, external axial load. Monitor operating temperature regularly to detect early signs of contact fatigue and surface pitting.