1 Complete Model & Code Explanation

Model: 7013 ACD/P4ADBA

Code Definition

7013: Light series precision angular contact ball bearing basic dimension

ACD: 25° heavy-duty contact angle, high axial rigidity, strong anti-tilting capacity, moderate limiting speed

P4A: P4A ultra-precision grade

DBA: Factory DB back-to-back pre-matched bearing set (2 pcs matched as DB arrangement)

Note: Single unit model:7013 ACD/P4A; Matching suffix series: DBA(DB), DFA(DF), DTA(DT); Standard all-steel bearing without ceramic or raceway coating; Extended comparative model:7013 ACD/HCP4ADBA (hybrid ceramic DB matched set)

Key Dimensions

Single bearing dimension

Bore d: 65 mm

Outer diameter D: 100 mm

Width B: 18 mm

Contact angle: 25°

Structure: Single row open bearing, supplied as set of 2 pcs with factory DB back-to-back matching

Rolling element: High-carbon chromium bearing steel ball

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

Supply form: Two bearings per matched set with factory face height calibration for direct DB assembly

Pre-filled lubricant: None

Surface treatment: Standard mirror finish without functional coating

Note: Contact SKF for official load ratings and limiting speed data.

Full Product Attributes

Contact form: two-point contact

Number of rows: single row, set of two DB bearings

Matching mode: factory precision pre-matched DB back-to-back set

Precision class: P4A ultra-precision grade

Material: All-steel angular contact ball bearing

Seal: Open type, no seal

Note: The 25° ACD contact angle delivers excellent axial rigidity and anti-tilting performance for continuous heavy milling. DBA stands for factory DB matched set with unified face height tolerance. Compared with random on-site assembly, it achieves consistent spindle temperature rise and stable rotational accuracy. Standard all-steel construction has no insulation capability, not applicable for built-in motor spindles with shaft current, best suited for belt-driven spindles. No protective raceway coating requires clean lubricant and stable operating impact.

Open design eliminates seal drag; continuous oil-air lubrication is preferred. High-speed spindle grease can be adopted for intermittent short-cycle operation. Spindle structure must be equipped with labyrinth or air curtain dust-proof device.

2 Structure & Operating Characteristics

Japan NMT 7013 ACD/P4ADBA consists of two 7013 ACD/P4A bearings with factory DB back-to-back matching. All components are made of high-carbon chromium bearing steel, raceways and balls processed by mirror ultra-precision grinding. The 25° contact angle enhances axial load and rigidity. Face heights are screened and calibrated in factory to guarantee matching precision.

Designed for belt-driven spindle units of vertical machining centers, CNC engraving & milling machines and precision grinders. Suitable for mass machine assembly to reduce on-site bearing selection workload, applied on general precision equipment with long-term heavy cutting and strict cost control.

3 Core Performance Advantages

1. 25° ACD heavy-duty contact angle: Outstanding axial load capacity and anti-tilting rigidity, suitable for high-feed continuous heavy milling.

2. P4A ultra-precision grade: Strict runout control to ensure geometric machining accuracy of spindle.

3. DBA factory DB pre-matched set: Factory-calibrated face height, no on-site bearing sorting, higher assembly efficiency and uniform preload distribution.

4. Mature all-steel construction: Stable supply, short lead time and obvious comprehensive cost advantage.

5. Open non-sealed design: No sealing friction loss, fully compatible with oil-air lubrication for long continuous high-speed operation.

6. DB back-to-back layout: Superior moment stiffness, strong capacity for bidirectional axial load and tilting load.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A precision matched bearings should be assembled in constant-temperature dust-free clean workshop. Remove all burrs, dust and metal debris on shaft and housing mating surfaces. Adopt controlled thermal mounting with temperature limit; open flame heating is prohibited. Never strike bearings to avoid indentation on raceways and balls. DBA matched set should be used as complete set; do not split and mix with other single bearings to prevent loss of matching accuracy.

5.2 Matching & Preload Instructions

Supplied as factory DB back-to-back double set, no re-matching required on site. Assemble strictly following DB back-to-back orientation. Medium preload recommended for continuous heavy cutting; light preload for light-load finishing. Avoid long-term full-speed operation under heavy preload to prevent excessive temperature rise.

Selection guide: ①Self-assembly on site → single unit 7013 ACD/P4A; ②Direct DB double assembly to save working hours →7013 ACD/P4ADBA; ③Built-in spindle anti-electric corrosion requirement →7013 ACD/HCP4ADBA ceramic matched set; ④High-speed light load condition →18°AC or 15°C matched bearing series.

5.3 Lubrication Matching Solutions

No pre-filled lubricant. Oil-air forced circulation lubrication recommended for long continuous high-speed operation. Special high-speed spindle grease only permitted for short intermittent machining. Install precision filter on oil circuit to keep lubricant clean; hard contaminants easily cause raceway scuffing. Do not mix lubricants from different brands or specifications.

5.4 Speed Parameter Note

Limiting DN speed is lower than 18°AC and 15°C contact angle series. Reserve sufficient speed safety margin under continuous heavy load; long-term operation near limiting speed is not recommended.

6 Daily Maintenance & Fault Troubleshooting

Carry out multi-stage low-speed running-in after assembly; raise speed to rated value only after temperature rise and vibration stabilize. Open bearings have no built-in dust shield; front spindle dust seal cannot be omitted.

Maintain continuous supply of clean lubricant to avoid dry friction caused by oil starvation. When abnormal heating, noise or sudden vibration occurs, inspect sequentially: oil supply & lubricant cleanliness, over-limit preload, assembly coaxial accuracy, dust seal condition, cutting impact load. For all-steel bearings, strictly manage lubricant cleanliness to delay raceway fatigue pitting.