INDUSTRY COMPONENT

Circular Spline

Circular Spline is the flexible outer gear component in Harmonic Drive systems that enables high-ratio precision motion transmission.

Component Specifications

Definition
The Circular Spline is a thin-walled, flexible cylindrical gear component in Harmonic Drive gear systems that engages with the Wave Generator and Flexspline to create controlled elastic deformation, enabling high reduction ratios (typically 50:1 to 320:1) with zero-backlash, high torque capacity, and exceptional positional accuracy through harmonic motion principles.
Working Principle
The Circular Spline remains stationary as the fixed outer gear. The Wave Generator (elliptical cam) deforms the Flexspline, causing its teeth to engage progressively with the Circular Spline's internal teeth. This creates a relative rotational motion between components through elastic deformation rather than conventional sliding contact, resulting in smooth, precise motion transmission with minimal wear.
Materials
High-strength alloy steel (SCM415, SCM420, SNCM220) with carburizing or nitriding surface hardening (HRC 58-62), stainless steel (SUS304, SUS630) for corrosion resistance, or special alloys for extreme environments. Surface finish: Ra 0.8μm or better.
Technical Parameters
  • Module 0.2-2.0
  • Backlash ≤1 arc-min (often zero)
  • Lubrication Grease (Molykote, Kluber) or oil bath
  • Reduction Ratio 50:1 to 320:1
  • Positional Accuracy ≤30 arc-sec
  • Torsional Stiffness 5-50 Nm/arc-min
  • Operating Temperature -40°C to +120°C
Standards
ISO 1328-1, DIN 3960, JIS B 1702, AGMA 2000

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Circular Spline.

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Fatigue failure from cyclic stress concentration
  • Tooth wear from improper alignment
  • Corrosion in harsh environments
  • Thermal expansion mismatch
  • Lubrication degradation
FMEA Triads
Trigger: Excessive cyclic loading beyond fatigue limits
Failure: Crack initiation and propagation in tooth root
Mitigation: Implement load monitoring, use S-N curve based design, apply shot peening to compressive stress layer
Trigger: Misalignment during assembly
Failure: Uneven tooth contact leading to premature wear
Mitigation: Use precision alignment fixtures, laser alignment verification, thermal compensation design
Trigger: Inadequate lubrication or contamination
Failure: Increased friction, overheating, and surface degradation
Mitigation: Sealed housing design, scheduled lubrication maintenance, particle filtration systems

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Tooth profile tolerance: IT4-IT5, Concentricity: ≤0.01mm, Surface roughness: Ra ≤0.8μm
Test Method
Coordinate measuring machine (CMM) verification, backlash measurement with torque application, fatigue testing per ISO 6336, thermal cycling validation

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the main advantage of Circular Spline in Harmonic Drives?

It enables zero-backlash operation through elastic deformation rather than sliding contact, providing exceptional positional accuracy and repeatability unmatched by conventional gears.

How does tooth engagement differ from traditional gears?

Approximately 30% of teeth engage simultaneously (vs 1-2 in spur gears), distributing load evenly across multiple teeth for higher torque capacity and smoother operation.

What maintenance is required for Circular Splines?

Minimal maintenance: periodic lubrication every 5,000-10,000 hours with specified grease, contamination protection, and avoidance of shock loads exceeding rated capacity.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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Circle Circumferential Seam