Tension Spring

A tension spring (or extension spring) is a common type of mechanical spring designed to withstand axial tensile forces and return to its original shape after unloading. Below is a detailed introduction to tension springs:

1. Basic Structure

• Hook Designs: The ends of tension springs typically feature hooks (e.g., round hooks, half hooks, English hooks) for attachment and force application.
• Close-Wound Coils: In their free state, the coils are usually tightly wound (with preload stress) to ensure even force distribution.

2. Working Principle

• Elastic Deformation: When stretched, the coils expand, creating elastic deformation within the material and storing energy.
• Restoring Force: Upon force removal, the spring returns to its original length, releasing stored energy.

3. Key Parameters

• Material: Commonly made of high-carbon steel, stainless steel (e.g., 304/316), music wire, or alloy steel.
• Wire Diameter (d): Diameter of the spring wire.
• Outer Diameter (OD): Maximum diameter of the spring.
• Free Length (L₀): Total length when unloaded.
• Stiffness (k): Force required per unit deformation (N/mm or lb/in).
• Maximum Extended Length: Exceeding this may cause permanent deformation.

4. Applications

• Industrial Machinery: Valves, clutches, automated assembly lines.
• Automotive: Brake systems, suspension components.
• Household Appliances: Washing machine counterweights, switch buttons.
• Medical Equipment: Surgical instruments, rehabilitation devices.

5. Selection Considerations

• Load Requirements: Choose stiffness and material based on maximum force and displacement.
• Environmental Factors: Opt for stainless steel or coated springs in humid conditions.
• Fatigue Life: High-cycle designs for frequent use.
• Installation Space: Ensure hook dimensions match connecting parts.

6. Common Issues

• Permanent Deformation: Caused by overloading or material fatigue.
• Hook Breakage: Due to stress concentration or improper installation.
• Corrosion: Occurs in harsh environments without corrosion-resistant materials.

7. Maintenance & Replacement

• Regular Inspection: Check for rust, deformation, or cracks.
• Lubrication: Apply light oil to friction points (if needed).
• Replacement Criteria: Replace when elasticity significantly declines or damage occurs.

            Shuangyuan produce various tension spring with wire diameter from 0.03-16mm

                       Tension Spring                                   Tension Spring 

                      Tension Spring