- NOKS INTERNATIONAL TRADE GROUP LIMITED.
- Email : info@noksbearings.com
- © 2025 noksbearings sitemap
IKO’s specialized inner rings serve as critical load-transfer components in customized bearing systems, engineered to optimize stress distribution and rotational accuracy. Designed for integration with IKO rollers and cages, these rings achieve micron-level geometric consistency through proprietary grinding technologies.
1.IKO’s inner rings Design Specifications
1.1 Geometric Configuration
Raceway Profiles:
| Type | Radius Ratio (r/Dw) | Contact Angle | Stress Reduction |
| Logarithmic | 0.52-0.55 | 30°-45° | 40% vs. circular |
| Gothic Arch | 0.51-0.53 | 25°-30° | 35% |
| Double Arc | 0.54-0.56 | 35°-40° | 45% |
Bore Types:
Cylindrical: Standard tolerance h5/h6 (ISO 286)
Tapered: 1:12 (JIS B 1504) or 1:30 (DIN 720)
Flanged: Integrated flange width 2-15mm (DIN 5419)
1.2 Dimension Series
| Inner Ring Code | Bore Diameter (mm) | Raceway OD (mm) | Width (mm) |
| IR-02 | 10-30 | 15-40 | 8-12 |
| IR-05 | 25-80 | 35-100 | 12-20 |
| IR-10 | 70-200 | 90-240 | 20-40 |
2.1 Metallurgical Composition
Standard Material:
Vacuum arc remelted (VAR) SUJ2 steel
Chemical composition (%):
| C | Si | Mn | Cr | Mo |
| 1.00 | 0.25 | 0.35 | 1.45 | 0.08 |
Alternative Materials:
| Grade | Hardness (HRC) | Application |
| SUS440C | 56-58 | Corrosive environments |
| M50NiL | 60-62 | Aerospace bearings |
| Hybrid Ceramic | HV1500 | Non-conductive zones |
2.2 Heat Treatment Processes
Case Hardening:
Depth: 0.8-2.0mm (adjustable)
Surface hardness: 60-64 HRC
Core hardness: 58-62 HRC
Subzero Treatment:
-196°C deep cryogenic stabilization
Residual austerity reduction: <3%
3.1 Machining Tolerances
| Parameter | Standard Grade | Precision Grade | Ultra-Precision Grade |
| Bore roundness | ≤3μm | ≤1.5μm | ≤0.8μm |
| Raceway waviness | ≤0.15μm/10mm | ≤0.08μm/10mm | ≤0.03μm/10mm |
| Face parallelism | ≤5μm | ≤2μm | ≤1μm |
3.2 Surface Engineering
Superfinishing:
3-stage diamond grinding (Ra ≤0.05μm)
Surface compression: 800-1,200 MPa residual stress
Protective Coatings:
| Coating Type | Thickness | Friction Coefficient | Temp Limit |
| Black Oxide | 2-4μm | 0.12-0.15 | 200°C |
| DLC (a-C:H) | 1-2μm | 0.06-0.08 | 350°C |
| TiAlN | 3-5μm | 0.10-0.12 | 800°C |
4.1 Static Capacity
Maximum Contact Stress:
σ_max = 0.418√(PE/(R×L))
(P: load [N], E: modulus [GPa], R: curvature radius [mm], L: contact length [mm])
Allowable stress: 4,200 MPa (standard) / 4,800 MPa (premium)
4.2 Fatigue Life Enhancement
Life Adjustment Factors:
| Factor | Standard Ring | Enhanced Ring |
| Material purity | 1.0 | 1.5 |
| Surface finish | 1.0 | 2.0 |
| Stress relief | 1.0 | 1.8 |
5.1 High-Speed Spindles
Balanced Inner Rings:
G2.5 balance grade (ISO 1940-1)
Maximum rotational speed: 50,000 rpm (Φ30mm bore)
Thermal expansion coefficient: 11.7×10⁻⁶/°C
5.2 Heavy-Duty Gearboxes
Hardened Flange Series:
Flange shear strength: 1,200 MPa
Spline options: DIN 5480/5482 standards
Anti-wear grooves (0.3mm depth × 1.5mm width)
5.3 Cleanroom Applications
Particle Generation Control:
<0.1 particles/cm³ (>0.3μm)
Electropolished surface (Ra ≤0.02μm)
Vacuum-compatible up to 10⁻⁷ Pa
6.1 Shaft Fitting Guidelines
| Fit Type | Interference (μm) | Application Scenario |
| Loose fit | 0-5 | Aluminum housings |
| Transition fit | 5-15 | Moderate dynamic loads |
| Press fit | 15-30 | High vibration environments |
| Hydraulic fit | 30-50 | Large diameter (>200mm) |
6.2 Thermal Mounting Formulas
Heating Temperature Calculation:
ΔT = δ/(α×d) + 20
(ΔT: temperature rise [°C], δ: interference [mm], α: expansion coefficient [1/K], d: bore [mm])
Example: Φ50mm steel ring with 0.02mm interference → 80-90°C
7.1 Inspection Protocols
Dimensional Metrology:
3D CMM measurement (ISO 10360-2)
Roundness tester (ISO 12181)
Surface profilometer (ISO 4287)
Material Testing:
| Test | Standard | Acceptance Criteria |
| Hardness depth | ISO 2639 | Case depth ±0.1mm |
| Inclusion rating | ASTM E45 | ≤0.5 (K4 scale) |
| Residual austenite | ASTM E975 | ≤3% |
7.2 Certification Standards
Material Traceability:
EN 10204 3.1/3.2 certification
Heat number tracking via blockchain
Industry Compliance:
IATF 16949 for automotive
AS9100D for aerospace
ISO 13485 for medical
8.1 Special Features
Lubrication Channels:
Radial oil holes (Φ1-Φ3mm)
Helical grease grooves (30°-45° helix angle)
Sensor Integration:
Embedded strain gauges (350Ω)
Temperature sensor pockets (PT100 compatible
8.2 Non-Standard Modifications
| Request | Technical Solution | Lead Time |
| Non-circular bores | EDM machining (±0.005mm) | 8 weeks |
| Hybrid materials | Laser cladding (Stellite/WC-Co) | 12 weeks |
| Multi-stage tapers | CNC profile grinding | 6 weeks |
| Part Number | Bearing Type | Bearing Material | Internal Structure | Dynamic Load Rating (N) | Mass(g) |
|---|---|---|---|---|---|
Inner Rings |
High Carbon Chrome Steel |
36 |
|||
Inner Rings |
High Carbon Chrome Steel |
30,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
41,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
52,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
19,1 |
|||
Inner Rings |
High Carbon Chrome Steel |
18 |
|||
Inner Rings |
High Carbon Chrome Steel |
11 |
|||
Inner Rings |
High Carbon Chrome Steel |
15,2 |
|||
Inner Rings |
High Carbon Chrome Steel |
22,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
7,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
8,1 |
|||
Inner Rings |
High Carbon Chrome Steel |
9,3 |
|||
Inner Rings |
High Carbon Chrome Steel |
16,4 |
|||
Inner Rings |
High Carbon Chrome Steel |
9,9 |
|||
Inner Rings |
High Carbon Chrome Steel |
13,6 |
|||
Inner Rings |
High Carbon Chrome Steel |
10,5 |
|||
Inner Rings |
High Carbon Chrome Steel |
11,7 |
|||
Inner Rings |
High Carbon Chrome Steel |
12,3 |
|||
Inner Rings |
High Carbon Chrome Steel |
16,8 |
|||
Inner Rings |
High Carbon Chrome Steel |
21,5 |