Core Parameters and Representation Methods of Conical Springs
The specifications of conical springs (commonly known as tower springs) must be clearly expressed through the following key parameters:
Diameter Parameters: Large end diameter (D) and small end diameter (d), typically with a tolerance of ±0.1mm (refer to GB/T 1239.2-2009). For example, a spring with D=30mm and d=15mm indicates a significant difference in diameter between the two ends, suitable for applications requiring gradual compression.
Free Height (H₀): The total height when unloaded, commonly ranging from 10-200mm. A spring with H₀=50mm is suitable for space-constrained buffer devices.
Wire Diameter (t): The diameter of the spring wire, generally 0.5-10mm, directly affecting stiffness. For every 1mm increase in wire diameter, the load capacity increases by approximately 15% (according to the 5th edition of the *Mechanical Design Handbook*).
Effective Coils (n): Typically 3-15 coils; more coils result in a softer elasticity.
Specifications and Industry Standards
Specification Format: The industry standard format is "D×d×H₀×t×n-Material Grade". For example: 30×15×50×2×8-60Si2MnA, indicating a truncated cone spring with a large end of 30mm, a small end of 15mm, a free height of 50mm, a wire diameter of 2mm, 8 coils, and made of 60Si2MnA material.
Material Selection:
60Si2MnA (High-stress scenarios, allowable stress up to 980MPa)
304 Stainless Steel (Corrosion resistant, allowable stress 620MPa)
Phosphor Bronze (Conductivity requirements, elastic modulus 110GPa)
Extended Applications and Precautions
Non-standard Customization: For variable stiffness designs, the taper ratio (D/d) can be adjusted. For example, when D/d=2.5, the spring is initially compliant and later becomes more rigid.
Installation Recommendations: Truncated cone springs must be used with a guide shaft to avoid failure due to uneven loading. A radial clearance of 0.5-1mm is recommended. Life test: According to JB/T 7366-2015 standard, the deformation of a 60Si2MnA spring should be ≤5% after 2 million cycles.
