1 Complete Model & Code Explanation

Model: 7015 ACDGC/P4A

Code Definition

7015: Basic dimension of 70 series light-duty single-row angular contact ball bearing

ACD: 25° nominal contact angle, machined solid brass cage design

G: Continuous oil-air circulation grooves machined on outer ring outer circumference

C: Optimized cage geometry to reduce fluid agitation loss for ultra-high speed operation

P4: ISO P4 super precision grade, meets high-precision rotation requirements of high-speed spindles

Supply form: Supplied as separate single bearings without factory duplex matching

Important reminder: This is single bearing without fixed factory pairing. DB, DF or DT duplex arrangement is realized by customer precision spacers. Direct interchange with factory end-ground duplex bearing sets is not recommended. Protect outer ring grooves during assembly to avoid debris blockage.

Suffix Comparison within Series

7015 ACD/P4A: Single bearing, 25° contact angle, P4 precision, no outer ring lubrication grooves, standard brass cage

7015 ACDG/P4A: Single bearing, 25° contact angle, P4 precision, outer ring oil-air grooves, standard brass cage

7015 ACDGC/P4A: Single bearing, 25° contact angle, P4 precision, outer ring oil-air grooves, high-speed optimized brass cage (this model)

Core Basic Dimensions

Bore d: 75 mm

Outer diameter D: 115 mm

Width B: 20 mm

Structure: Single-row open-type angular contact ball bearing, supplied individually

Rolling element: High-precision bearing steel balls (all steel construction)

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

Cage: High-speed optimized machined solid brass cage

Outer ring feature: Continuous integrated oil-air circulation grooves on outer ring surface

Pre-filled lubricant: None

Delivery form: Individually packed single unit, no matching marks

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 bearing, supports multi-unit combined pairing on site

Pairing property: Independent single unit, no factory matching; DB back-to-back / DF face-to-face / DT tandem layout realized by customer spacers

Precision class: P4 high-speed super precision grade

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

Seal structure: Open type, non-sealed

Special construction: Continuous oil-air circulation grooves on outer ring; optimized cage profile to cut fluid turbulence heat under ultra-high rotating speed

Note: ACD stands for 25° contact angle delivering higher axial rigidity than 15° designs, suitable for milling under moderate alternating axial loads. Suffix G outer ring oil grooves enable outer-ring lubrication layout and simplify housing machining. Suffix C represents cage optimization with improved internal oil flow channels to reduce churning loss at extreme speeds.

Open design fits oil-air lubrication and circulating oil lubrication; long-term continuous high-speed grease lubrication is not recommended. As individual bearings without preset preload, preload magnitude is fully controlled by precision spacers, ideal for prototype development and customized machinery allowing flexible light, medium or heavy preload selection.

2 Structure & Operating Characteristics

Japan NMT 7015 ACDGC/P4A is premium all-steel 25° contact angle, P4 super precision single-row angular contact ball bearing of 7015 series. Inner and outer rings are made of high-carbon chromium bearing steel with stabilized heat treatment to eliminate residual stress. Multi-stage mirror super-finishing on raceways reduces vibration amplitude and running noise during high-speed rotation.

Rolling elements are combined with high-speed optimized machined solid brass cage. Improved internal flow channels minimize lubricant churning loss at high speed. Excellent heat resistance withstands transient temperature spikes during cutting and maintains dimensional stability during prolonged ultra-high speed operation. Continuous pre-machined oil-air circulation grooves on outer ring enable uniform lubricant distribution for outer-ring supply layout and simplify housing oil channel design.

Bearings are delivered as separate singles without fixed pairing restrictions. Equipment manufacturers can assemble two or three bearings with precision spacers into DB, DF or DT configurations according to spindle design and adjust preload freely. Standardized outer-ring lubrication structure facilitates universal housing design for new spindle development. Widely used in prototype spindles and customized multi-specification spindle projects to sustain stable rotational accuracy during finishing operations.

3 Core Performance Advantages

1. ACD 25° contact angle with high-speed optimized brass cage: Sufficient axial rigidity to bear moderate alternating milling loads; optimized cage lowers lubricant churning heat for continuous ultra-high DN operation.

2. G-type outer ring oil-air circulation grooves: Lubricant distribution along outer ring, supporting outer-ring lubrication layout and lowering housing machining costs.

3. Supplied as individual single bearings for flexible pairing: DB/DF/DT layouts achievable with precision spacers; preload adjustable on demand without factory pre-setting.

4. ISO P4 super precision grade: Strictly control radial and axial runout to maintain long-term high-precision cutting performance of spindles.

5. Open non-sealed construction: Zero seal friction loss, perfectly compatible with oil-air forced lubrication and circulating oil lubrication systems.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4 super precision bearings must be assembled in constant-temperature dust-free clean workshops. Remove all burrs and metal debris on shaft and housing mating surfaces. Controlled thermal mounting method is recommended; open-flame heating is forbidden. Never strike bearing rings to prevent indentations on raceways.

Important reminder: 7015 ACDGC/P4A is independent single bearing without factory pairing. On-site duplex assembly requires precision spacers with qualified flatness and parallelism. Protect outer ring circulation grooves during assembly to avoid debris blocking oil flow.

5.2 Pairing & Preload Instructions

Supply condition: Individual single bearing, no factory preset preload, no matching marks.

Available mounting arrangement: DB back-to-back, DF face-to-face, DT tandem; preload level determined by spacer dimensions.

Selection tips:

Prototype development, multiple preload tests, outer ring oil-air supply, ultra-high speed demand → Prioritize 7015 ACDGC/P4A;

Mature mass-production spindles requiring simple assembly without on-site preload adjustment → Select factory pre-ground duplex sets such as 7015 ACD/P4ADGA / 7015 ACD/P4DGB;

Housing with built-in oil passages without demand for outer ring grooves → Choose standard single bearing 7015 ACD/P4A;

Medium speed range with no requirement for optimized cage → Adopt 7015 ACDG/P4A.

Selection reference:

① Single bearing, no outer ring grooves, standard cage →7015 ACD/P4A

② Single bearing, outer ring oil-air grooves, standard cage →7015 ACDG/P4A

③ Single bearing, outer ring oil-air grooves, high-speed optimized cage →7015 ACDGC/P4A(this model)

5.3 Lubrication Matching Scheme

No pre-filled grease. Oil-air forced circulation lubrication or circulating oil lubrication system is recommended; long-duration high-speed grease lubrication is not advised. High-precision filters shall be installed in lubrication pipelines; hard foreign particles will scratch mirror raceway surfaces. Mixing lubricants of different brands or base oil types is prohibited. Regularly clear carbon deposits and contaminants inside outer ring grooves to guarantee smooth oil circulation. Maintain high lubricant cleanliness to reduce raceway fatigue wear risk for all-steel precision bearings.

5.4 Speed Parameter Note

C-type optimized brass cage effectively reduces fluid churning heat at high speed and delivers higher achievable DN value compared with standard cage variants. Preload magnitude is fully controlled by matched spacers; light or medium preload can be selected based on target rotating speed and cutting load. The complete machine shall be equipped with efficient cooling system and sufficient speed safety margin. Open bearings have no built-in dust shield; bearing housing must be designed with reliable external sealing against dust and cutting fluid to prevent abrasive damage on rolling elements and raceways.

6 Daily Maintenance & Fault Troubleshooting

After bearing assembly and spacer selection, carry out multi-stage low-speed running-in, continuously monitor temperature rise and vibration indicators. Only raise rotating speed to rated high speed after all data stabilize. Continuously track spindle temperature variation during running-in phase. Regularly inspect external housing sealing integrity, oil-air pipeline pressure and flow rate, confirm outer ring grooves remain free of blockage for uniform lubricant supply.

When steady abnormal noise, rapid temperature rise or growing vibration occurs, check sequentially: lubricant cleanliness, outer ring groove clogging, assembly coaxiality, spacer flatness and parallelism, abnormal preload caused by mismatched spacer size, excessive axial locking force, external impact load and foreign matter entering raceway.

Typical failure modes of freely combined single precision bearings include abrasive wear of raceways, surface pitting, local overheating caused by blocked grooves and uneven oil supply, unbalanced preload resulting from low-precision spacers, excessive tightening and long-term overloaded operation. Conduct regular online monitoring of temperature and vibration to detect incipient bearing damage in advance and prevent unexpected spindle shutdown.