Demands on Valve Springs

High Performance Car
High Dynamic Performance High Spring Load
and High Natural Frequency (Active Weight Reduction)
Valve Spring

High Fatigue Strength (Higher Stress Design)
Best Spring Design
High Durability (108 cycles)

Valve Spring Development
- In Search of Precision and Strength -

History of Valve Spring Development
Process Development & Manufacturing Technique
Design (Endura-Tech Valve Spring Varieties)

Evaluation Tools for Valve Spring

Process Development & Manufacturing Technique

100 % Inspection System of Spring Height during Coiling Process
100 % Inspection System for Completed Mass Production Springs
Original Heat Setting Facilities
Specialized Heat Treatment Process
New Shot-Peening Process "Double", "Advanced" Method
Twist Control for Ovate Wire Coiling

Design Development Topics

2-Step Pitch Valve Spring .... Patented
Ovate Section Valve Spring (by FEM Analysis) ... Patented
Tag End Profile Analysis .. Prevent Tag End Failure
3-Step Pitch and New 2-Step Pitch (Symmetric Shape) ... Patented
Valve Train Simulation

Valve Spring Varieties

Valve Spring Pitch vs. Load Characteristic

Spring Pitch vs. Dynamic Stress & Weight

Evaluation Tools and Methods for Valve Spring Development

1. Engine Motoring Test (Analyzing Items)
Valve Action (Jump, Bounce, Rotation)
Spring Stress
Engine Noise
Durability Test
2. Automatic Spring Pitch Measuring Equipment
3. X-ray Residual Stress Analyzer
4. Material Evaluation Testers
5. Fatigue Testers (wires & springs)
6. FEM Analysis
7. Rockwell Hardness Test
8. SEM with Chemical Composition Analyzer