B7304P4DU P4 Precision 40° Angular Contact Ball Bearing 20x52x15mm Single Side

1. Product Overview

B7304P4DU is single row super precision sealed angular contact ball bearing, standard metric dimension 20mm inner bore × 52mm outer diameter × 15mm single bearing width.
Full Model Code Explanation:

• B: 40° large contact angle, outstanding single-direction axial load capacity
• 7304: Medium heavy series angular contact ball bearing base size, inner bore 20mm
• P4: ISO P4 super precision grade, ultra-low radial & axial runout for high accuracy equipment
• DU: Single side contact rubber lip seal, built-in dust & impurity barrier, pre-filled long-life EP grease inside cavity

Adopts GCr15 high carbon chrome bearing steel for inner ring, outer ring and steel balls, matched with lightweight phenolic resin cage. 40° large contact angle design greatly improves axial rigidity, can bear combined heavy radial and unidirectional axial load simultaneously. Single-side DU contact seal effectively blocks cutting fluid, metal powder and workshop dust from invading internal raceway, avoids frequent re-lubrication. Open opposite side structure supports circulating oil lubrication for continuous high-speed cooling. Widely applied to CNC machining center spindles, heavy-duty gear reducers, compressor rotors, printing machinery main shafts, automated equipment positioning shafts and all precision transmission equipment with dust-proof & high-stiffness requirements.

2. Technical Specifications

Mounting dimension drawings, CNC spindle assembly matching guides and dust-proof long-life durability test reports can be provided on customer request.

3. Core Advantages

1. 40° large B contact angle, much stronger axial bearing capacity than 15°/25° contact angle bearings, stable positioning under alternating forward/reverse axial impact load.
2. ISO P4 super precision tolerance control, ultra-mirror superfinished raceway surface, strictly limited radial and axial runout, meets micron-level spindle rotation accuracy demand.
3. Single side DU reinforced contact lip seal, good barrier performance against metal chips, cutting fluid and dry dust, prevents raceway abrasion and premature grease loss.
4. Sealed inner cavity factory pre-filled high-temperature extreme pressure anti-wear grease, realizes long-term maintenance-free operation for semi-sealed spindle structures.
5. Lightweight phenolic resin cage, low centrifugal force loss under high-speed rotation, effectively avoid cage deformation and abnormal vibration noise during continuous operation.
6. Standard unified interchangeable metric dimensions, fully compatible with global mainstream B7304P4DU sealed precision angular contact bearings, direct replacement without modifying spindle housing and shaft size.
7. Unsealed opposite side design allows smooth circulation of cooling oil, rapid heat dissipation to prevent grease carbonization and bearing ablation under long high-speed heavy load.
8. Rich customizable options: DD double lip sealed upgrade, brass machined high-speed cage, DB/DF duplex pre-matched paired sets, OEM laser marking on outer ring, neutral export anti-rust carton packaging, high-temperature synthetic grease filling.

4. Application Scenarios

B7304P4DU single lip DU sealed P4 precision angular contact ball bearing is high-rigidity dust-proof rotary spare part matched with 20mm shaft heavy precision industrial equipment:

• CNC lathe, milling machine, machining center spindle support bearing assemblies
• Heavy helical gear reducer, planetary gearbox input/output shaft positioning units
• Air compressor, refrigeration compressor rotor high-speed support components
• Offset printing press, paper machinery main long transmission shaft bearing sets
• Automated welding equipment, precision testing instrument rotary positioning assemblies
• Hydraulic pump drive shaft axial limit & radial support bearing parts

Aftermarket interchangeable 7300 series B-type P4 DU sealed precision angular contact ball bearing
High stiffness dust-proof precision spindle bearing solution for machine tool spindle manufacturers, heavy reducer OEM factories and automation equipment bulk maintenance procurement.

5. Why Choose GQZ Bearing

We have 25 years of mature professional manufacturing experience for 7300 series B-type P4 precision DU sealed angular contact ball bearings including B7304P4DU spindle dedicated models.
Our B7304P4DU bearings adopt unified international ISO precision dimensional standards, consistent dynamic/static load parameters, GCr15 quenching heat treatment and P4 ultra-precision grinding process standards, fully dimensionally interchangeable with original brand precision spindle bearings.
Complete OEM & ODM customized service system, supporting single/double lip seal transformation, brass cage upgrade, duplex DB/DF matched preload groups and personalized outer ring marking demands.
Strict pre-delivery full quality inspection workflow: GCr15 steel raw material hardness test, steel ball automatic sorting screening, long-cycle high-speed alternating axial load rotation aging test, P4 runout precision one-by-one batch inspection, sealing lip leakage resistance test.
Professional precision spindle bearing technical team provides one-to-one radial-axial combined load matching calculation, spindle interference fit tolerance design and dual oil-grease mixed lubrication maintenance guidance within 24 working hours.
Standardized super precision bearing grinding production workshop provides competitive factory direct bulk wholesale price, stable long-term mass supply for global CNC machine tool, compressor and automation machinery spare parts purchasers.
We specialize in 7300 series P4 grade sealed high contact angle angular contact ball bearings, strict mirror raceway superfinishing and DU sealing lip anti-contamination quality control, committed to long-term stable win-win cooperation with high-rigidity precision dust-proof transmission equipment suppliers.

6. Quality Control

• Raw material chemical composition, hardness and fatigue resistance inspection for GCr15 inner/outer ring and steel ball blanks
• Precision CNC hard turning forming processing, multiple stress relief tempering cycles, ultra-precision mirror superfinishing grinding for 40° angular contact curved raceway surfaces
• Spherical steel ball high-temperature integral quenching, nano mirror polishing and high-precision automatic sorting production line
• Phenolic resin cage precision stamping forming process, single bearing assembly clearance inspection, EP anti-wear grease quantitative filling & sealing curing procedure
• Targeted professional performance testing: B7304P4DU long-cycle CNC spindle high-speed alternating axial impact rotation aging test, cutting fluid dust mixed environment anti-contamination durability simulation test, P4 grade radial runout precision one-by-one detection
• Comprehensive re-inspection of overall dimensional tolerance, inner bore roundness and DU sealing flatness before anti-rust oil coating and export moisture-proof carton packaging.

Each production batch of B7304P4DU bearings undergoes CNC spindle continuous cycle heavy load simulation test to guarantee stable low-vibration dust-proof high-rigidity rotary support performance for 20mm shaft precision heavy transmission systems.

7. Get A Quote Now

If you need B7304P4DU 20x52x15 single side DU sealed P4 precision 40° angular contact ball bearings for CNC spindle / heavy reducer manufacturing, precision transmission assembly and industrial automation maintenance bulk matching, send your purchase demand directly.
Complete professional one-stop supporting services after sending inquiry:

• Formal official detailed quotation reply within 24 working hours
• One-to-one radial + single-direction axial combined heavy load matching calculation, spindle press-fit installation and dual oil-grease lubrication technical support provided by professional precision spindle bearing engineers
• Customized bearing performance upgrade options including DD double lip reinforced dust seal and DB back-to-back preload duplex matching
• Favorable factory direct bulk wholesale price for large quantity single model orders of B7304P4DU

Please provide purchase quantity, actual working conditions (continuous high-speed heavy axial load / workshop dust & cutting fluid pollution environment / P4 high rotation accuracy requirement) to obtain complete official quotation documents.

8. FAQ