Frequently Asked Questions

HCH Bearing Group specializes in producing six core precision bearing series:

• Deep Groove Ball Bearings — The most versatile rolling bearing, suitable for electric motors, automotive, home appliances, and precision instruments
• Flexible / Thin-Section Bearings — Ultra-thin cross-section design, used in robot joints, harmonic reducers, aerospace
• Miniature / Micro Bearings — Starting from 1mm bore diameter, used in micro motors, dental handpieces, drones
• Four-Point Contact Bearings — Bidirectional axial load capacity, used in harmonic reducers, automotive EPS steering systems
• Tapered Roller Bearings — High combined load capacity, used in RV reducers, construction machinery, heavy-duty transmissions
• Crossed Roller Bearings — Multi-directional compound load capacity, rotational accuracy ≤0.005mm, used in robot joints, CNC rotary tables

Annual output exceeds 800 million units, covering a full size range from 1mm bore diameter to several meters outer diameter.

Bearing selection requires comprehensive consideration of these factors:

• Load type and magnitude: Pure radial — deep groove ball bearings; combined — tapered roller or crossed roller; bidirectional axial — four-point contact
• Space constraints: Tight installation space — flexible/thin-section bearings or miniature bearings
• Accuracy requirements: Robot joints — P5/P4/P2 grade crossed roller or flexible bearings
• Speed requirements: High-speed (e.g., motors) — deep groove ball bearings, up to 30,000 RPM
• Operating environment: High-temperature, corrosive — stainless steel or special lubrication

Contact our technical team (james@hchbearing.com) with your parameters for a free selection proposal.

Both are used in robot harmonic reducers but have different strengths:

• Flexible Bearings (Thin-Section): Ultra-thin elastic deformation design, 30%-50% lighter — ideal for aerospace and lightweight robot joints
• Crossed Roller Bearings: Orthogonal cylindrical rollers, single bearing handles radial/axial/overturning loads, accuracy ≤0.005mm — ideal for high-precision, high-rigidity applications

In short: flexible bearings prioritize lightweight design, crossed roller bearings prioritize rigidity and precision.

Accuracy grades follow international standards — smaller number = higher precision:

• P0 (ABEC-1): Normal accuracy, general industrial use
• P6 (ABEC-3): Medium accuracy, motors and home appliances
• P5 (ABEC-5): High accuracy, machine tool spindles and precision motors
• P4 (ABEC-7): Ultra-precision, robot joints, CNC tables, medical devices
• P2 (ABEC-9): Highest accuracy, precision instruments and optics

HCH produces P0 through P2. Our CNAS-accredited lab provides certified inspection reports.

Common sealing types: 1) Open (no sealing): for oil lubrication, heat dissipation. 2) Shield (ZZ/2Z): metal cover, prevents large particles, low friction, high speed. 3) Contact seal (RS/2R): rubber seal, good dust/water protection, higher friction, medium-low speed. 4) Non-contact seal (LR): low friction sealing, balances dust protection and high speed. Selection based on: environment (dust/humidity), speed requirements, lubrication method, temperature range. HCH provides multiple sealing configuration options.

Bearing clearance is the measurable distance between inner and outer rings in unmounted state. Divided into radial and axial clearance. Clearance groups: C2 (small) → CN (standard) → C3 (large) → C4 (larger) → C5 (largest). Selection principles: 1) General conditions: CN standard; 2) Interference fit, temperature difference: C3/C4 large clearance; 3) High precision, low noise: C2 small clearance; 4) High speed: consider thermal expansion effect on clearance. HCH provides custom clearance services.

HCH implements rigorous international quality standards:

• IATF 16949: Automotive industry quality management system (automotive-grade products)
• ISO 9001: International quality management system
• CNAS-Accredited Laboratory: China National Accreditation Service for Conformity Assessment
• Zhejiang Province "SRDI" Enterprise: Specialized, Refined, Differential, Innovative

Equipment includes Taylor Hobson roundness testers (UK), SPECTRO spectrometers (Germany), ZEISS microscopes, and 30+ life testing machines.

Standard and special material options:

• Standard: GCr15 high-carbon chromium bearing steel — excellent wear resistance and fatigue life
• Stainless Steel: 440C — superior corrosion resistance for food, medical, humid environments
• Special Coatings: DLC (diamond-like carbon), chrome plating, and other treatments available

Contact our technical team for custom material or heat treatment requirements.

Service life depends on load, speed, lubrication, temperature, and contamination. HCH ensures longevity through:

• High-quality GCr15 bearing steel with precision heat treatment
• 30+ life testing machines for full-batch reliability verification
• 300+ digital production lines ensuring product consistency
• Comprehensive grease and oil lubrication solutions

Under standard conditions, design life is 20,000-50,000 hours. Contact us for L10 life calculation support.

IATF 16949 is the international automotive quality management standard, stricter than ISO 9001. This certification means: 1) Products meet automotive zero-defect requirements; 2) Complete quality traceability system; 3) Controlled through PPAP (Production Part Approval Process); 4) FMEA (Failure Mode Analysis) capability; 5) Batch consistency guaranteed. HCH achieved IATF 16949:2025 certification, supplying Bosch, Siemens and other industry leaders.

HCH offers flexible production with adaptable MOQ:

• Standard Products: Typically 100-500 units depending on model
• Custom Products: Generally starting from 1,000 units
• Samples: Free samples available for testing and validation

Contact sales: james@hchbearing.com | +86 574-6397-8888

HCH is known for rapid delivery — standard inventory held for only 3 days:

• Standard Products: Shipped within 3 days; urgent orders within 24 hours
• Custom Products: 2-4 weeks; expedited to 1-2 weeks
• Strategic Customers: Dedicated stock reservation

With 300+ digital production lines and full supply chain integration, HCH handles large-volume orders rapidly.

Please provide this information for an accurate quote:

• Bearing model number or drawing (for non-standard)
• Required quantity (annual or batch)
• Accuracy grade (P0/P6/P5/P4/P2)
• Material (bearing steel / stainless steel)
• Sealing type (Open / ZZ metal shields / 2RS rubber seals)
• Special requirements (temperature, speed, noise, etc.)

Send to james@hchbearing.com — detailed quotation within 1-2 business days.

HCH has a well-established global presence:

• Products exported to 70+ countries and regions
• 18 overseas direct sales companies
• Domestic offices in Dongguan, Wuhan, Chongqing
• Partners include Bosch, Siemens, Brose, Nidec, WEG

12-hour domestic on-site response; overseas customers receive localized support.

HCH capacity and delivery: 1) Annual capacity: 800 million precision bearings; 2) Production lines: 300+ intelligent digital lines; 3) Standard delivery: stock items ship in 3 days, urgent orders 24 hours; 4) Custom delivery: generally 2-4 weeks, expedited 1-2 weeks; 5) Strategic customers: dedicated stocking mechanism, supply stability; 6) Global delivery: 18 overseas companies, 70+ countries rapid response. Full supply chain control ensures quality and delivery reliability.

Yes, HCH has strong customization capabilities:

• 100+ R&D team + CNAS-accredited lab for custom development
• Core grinding equipment independently developed in-house for rapid non-standard production
• Full supply chain in-house (steel tube to assembly)
• SolidWorks, CAD — collaborative design support

Customization: non-standard dimensions, special materials, coatings, lubrication, sealing structures.

Full-chain robotics bearing solutions:

• Harmonic Reducers: Flexible bearings, crossed roller bearings, four-point contact bearings
• RV Reducers: Tapered roller bearings
• Joint Modules: Flexible bearings, crossed roller bearings
• Servo / Torque Motors: Deep groove ball bearings
• Dexterous Hands: Miniature bearings (from 1mm bore)

12 dedicated crossed roller bearing production lines commissioned May 2026.

Yes — free PDF downloads on the Downloads page:

• Deep Groove Ball Bearing Technical Manual
• Flexible / Thin-Section Bearing Technical Manual
• Miniature and Micro Bearing Technical Manual
• Four-Point Contact Bearing Technical Manual
• Tapered Roller Bearing Technical Manual
• Crossed Roller Bearing Technical Manual
• Grease Specification Sheet

For printed copies: james@hchbearing.com.