1 Complete Model & Code Explanation

Model: 7013 ACDGB/P4A

Code Definition

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

ACD: 25° contact angle, high axial rigidity and outstanding anti-tilting moment capacity

GB: Reinforced large-diameter ball structure, optimized raceway curvature based on GA design to expand effective contact area, higher load limit and impact resistance than ACDGA

P4A: P4A ultra-precision grade

Supply form: Independent single bearing, not factory pre-matched set, multiple bearings support free on-site pairing

Comparative reference models:

Standard ball single bearing: 7013 ACD/P4A

Basic large ball single bearing: 7013 ACDGA/P4A

Reinforced large ball single bearing: 7013 ACDGB/P4A

Hybrid ceramic reinforced large ball: 7013 ACDGB/HC/P4A

Factory DB matched assembly: 7013 ACDGB/P4ADBA / DBC / QBC series

Core Basic Dimensions

Bore d: 65 mm

Outer diameter D: 100 mm

Width B: 18 mm

Contact angle: 25°

Structure: Single row open type single bearing without seal

Rolling element: High-carbon chromium bearing steel, GB reinforced enlarged ball matched with optimized raceway curvature

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

Pre-filled lubricant: None

Surface treatment: Mirror finish for inner ring, outer ring and balls, no functional coating

Delivery form: Individually packed single unit, no matched spacer included

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

Full Product Attributes

Contact form: Two-point contact

Number of rows: Single row

Pairing property: Loose single unit without factory pairing mark, supports on-site DB/DF/DT pairing

Precision class: P4A ultra-precision grade

Material: All-steel angular contact ball bearing

Seal structure: Open type, non-sealed

Note: ACDGB is upgraded reinforced large ball version. Compared with ACDGA, it optimizes inner and outer ring raceway curvature to improve contact stress distribution and restrain stress concentration, suitable for continuous heavy cutting and strong intermittent impact conditions. The 25° large contact angle delivers superior axial load and anti-tilting performance. Open structure avoids heat generation caused by seal drag, recommended for oil-air forced lubrication. This product is supplied as single bearing. Spindle manufacturers need to select spacers separately, complete face height sorting and preload adjustment, which cannot replace factory pre-matched bearing sets. Without insulating coating, it is not applicable to built-in motor spindles with shaft current, preferred for belt-driven heavy-duty precision spindle units.

2 Structure & Operating Characteristics

Japan NMT 7013 ACDGB/P4A retains standard 7013 outer mounting dimensions, internally equipped with GB reinforced large ball structure. Inner and outer rings are made of premium high-carbon chromium bearing steel, subjected to stabilized heat treatment, aging treatment and multiple ultra-precision mirror grinding processes. Geometric accuracy and surface finish meet long-term operation standards of heavy-duty precision machine tool spindles.

Compared with ACD and ACDGA bearings of the same specification, ACDGB optimizes raceway matching curve, effectively reducing contact stress during operation, delaying raceway pitting initiation under heavy impact loads and extending service life. Open non-sealed design reduces high-speed friction resistance and maintains stable temperature control during continuous high-speed machining. Single-unit supply fully releases design freedom; spindle manufacturers can construct double, triple multi-bearing support structures according to spindle rigidity requirements.

3 Core Performance Advantages

1. GB reinforced large ball with optimized raceway curvature: Better contact stress distribution than ACDGA basic large ball type, further improved load rating and impact resistance, suitable for continuous heavy milling.

2. 25° ACD contact angle: Sufficient axial load capacity and high anti-tilting moment, applicable to heavy mold cutting and alternating multi-directional load processing.

3. P4A ultra-precision grade: Strict control of radial and axial rotational runout to guarantee dimensional accuracy stability for long-term mass production.

4. Open non-sealed design: Eliminate sealing friction loss and lower temperature rise, fully compatible with oil-air forced circulation lubrication system.

5. Flexible single-unit supply: No bundled spacers, manufacturers can independently choose DB/DF/DT layout and design spacers & preload scheme.

6. Standardized all-steel structure: Stable supply chain, controllable lead time, convenient for bulk stocking and assembly of heavy-duty spindle modules.

4 Main Application Fields

4.1 Belt-driven spindle units of heavy-duty vertical machining centers and large CNC mold engraving & milling machines

Working conditions with long-term heavy milling and frequent intermittent cutting impact; spindle manufacturers independently complete bearing pairing and preload commissioning.

4.2 Spindles of heavy internal & external grinders and precision gear heavy-load finishing equipment

Scenarios requiring high rigidity and strong anti-tilting capacity for medium and long-term continuous heavy-duty precision machining.

4.3 R&D of high-end heavy-duty spindle units and mass assembly of standardized heavy-load spindle modules

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A ultra-precision bearings shall be assembled in constant-temperature dust-free clean workshops. Thoroughly remove burrs, metal debris and dust impurities on shaft and housing mating surfaces. Adopt controlled thermal mounting with strictly limited heating temperature; direct open flame heating is prohibited. Never strike inner or outer ring to avoid indentation damage on raceways.

This is an independent single bearing. When multiple units are assembled together, face height screening and matching must be carried out on site. Random mixing assembly is forbidden, which will cause uneven load distribution, abnormal temperature rise and vibration.

5.2 Pairing & Preload Instructions

Supplied as independent single unit without pairing marks or attached spacers.

Optional arrangement: DB back-to-back, DF face-to-face, DT tandem.

Medium preload recommended for continuous heavy cutting; light preload for light-load finishing. Avoid long-time full-speed operation under heavy preload to prevent overheating aging.

Selection reference:

① General stable cutting →7013 ACD/P4A

② Medium impact cutting, basic large ball demand →7013 ACDGA/P4A

③ Continuous heavy cutting and strong impact conditions, priority for reinforced load capacity →7013 ACDGB/P4A

④ Factory DB matched complete set demand →7013 ACDGB/P4ADBC, 7013 ACDGB/P4AQBC series

⑤ Anti-electrocorrosion for motor spindles →7013 ACDGB/HC/P4A hybrid ceramic bearing

5.3 Lubrication Matching Scheme

No pre-filled lubricant. Oil-air forced circulation lubrication is preferred for long continuous high-speed heavy-duty operation. High-speed spindle grease can only be adopted for short intermittent processing. Install high-precision filter on lubrication pipeline to keep lubricant clean; hard impurities easily cause fatigue spalling of raceways. Do not mix lubricants of different brands and specifications.

5.4 Speed Parameter Note

GB reinforced large ball structure greatly improves load capacity, while limiting DN speed is slightly lower than ACD and ACDGA models of the same specification. Sufficient speed safety margin must be reserved for continuous heavy-load operation; long-term operation within limiting speed range is not recommended.

6 Daily Maintenance & Fault Troubleshooting

Carry out multi-stage low-speed running-in after assembly. Do not increase speed to rated working speed until temperature rise and vibration remain stable. Open bearing has no built-in dust-proof parts; labyrinth seal or air curtain dust-proof structure must be installed at spindle front end.

Maintain continuous supply of clean lubricant to avoid dry friction caused by oil starvation. In case of continuous abnormal noise, overheating and sudden vibration, inspect sequentially: oil supply status & lubricant cleanliness, bearing pairing accuracy, preload value, assembly coaxial accuracy and external cutting impact load. Regularly monitor spindle operating temperature to detect early fatigue damage of bearings in advance.