Common types of extension springs (tension springs) can be categorized based on shape, structure, application, and material. The following details typical types and characteristics from different perspectives:
Classification by Shape
Cylindrical Extension Springs
Features: Uniform coil diameter, simple structure, and low manufacturing cost make them the most widely used type.
Applications: General machinery, automotive door locks, furniture hinges, etc.
Examples: Common door catch springs and keyboard key rebound springs.
Conical Extension Springs
Features: The coil diameter gradually changes from one end to the other, resulting in variable stiffness (increasing stiffness when stretched).
Advantages: Provides greater elongation within confined spaces while maintaining a compact design.
Applications: Battery contact springs, aviation equipment, and medical devices (such as endoscopes).
Flat Extension Springs (Rectangular Section Springs)
Features: Wound with rectangular cross-section wire, they provide greater force within the same space.
Advantages: High load capacity, suitable for applications where space is limited but high tension is required.
Applications: Automotive clutches, heavy machinery buffers.
Double-Torsion Tension Spring
Features: Made of two counter-wound springs, it can simultaneously withstand tension and torque.
Applications: Applications requiring bidirectional force transmission, such as certain door hinges and tool handles.
Classification by Structure
Single-Hook Tension Spring
Features: Closed coil at one end, open hook at the other, facilitating one-way connection.
Applications: Simple tension applications, such as hooks and handles.
Double-Hook Tension Spring
Features: Hooks or loops at both ends, allowing for bidirectional connection.
Applications: Applications requiring symmetrical tension, such as balancers and tension adjustment devices.
German-Style Hook Tension Spring
Features: The hook is curved at 90 degrees, suitable for specific installation angles.
Applications: European standard machinery, automotive suspension systems.
British-Style Hook Tension Spring
Features: The hook is semi-circular, with a different angle than the German hook, adapting to various installation spaces.
Applications: British-standard equipment, industrial automation. Loose-Tube Tension Springs
Features: Large gaps between coils allow for free expansion and compression, reducing friction.
Applications: Applications requiring low friction and long life, such as precision instruments and electronic equipment.
Classification by Application
Constant-Force Tension Springs
Features: Special designs (such as variable pitch) ensure constant tension during extension.
Applications: Curtain rollers, cable retractors, and automatic balancing systems.
High-Precision Tension Springs
Features: High-precision manufacturing processes ensure tight tolerance control and stable performance.
Applications: Laboratory equipment, medical instruments (such as syringe plungers), and aerospace.
High-Temperature-Resistant Tension Springs
Features: Made of high-temperature-resistant materials (such as Inconel alloy and titanium alloy), they maintain elasticity in high-temperature environments.
Applications: Aircraft engines, gas turbines, and high-temperature industrial furnaces.
Corrosion-Resistant Tension Springs
Features: Surface coating or stainless steel is used to resist corrosive environments.
Applications: Marine equipment, chemical machinery, and food processing equipment.
Micro Tension Springs
Features: Fine wire diameter (less than 0.1mm), compact size, suitable for micro devices.
Applications: Mobile phone vibration motors, earphones, micro sensors.
Classification by Material
Stainless Steel Tension Springs
Features: High corrosion resistance, suitable for humid or chemical environments.
Applications: Medical devices, outdoor equipment, food processing machinery.
Carbon Steel Tension Springs
Features: High strength, low cost, but requires rust prevention.
Applications: General machinery, automotive parts, industrial tools.
Alloy Steel Tension Springs
Features: Alloying improves elastic limit and fatigue life.
Applications: High-load applications, such as heavy machinery and bridge vibration reduction.
Copper Alloy Tension Springs
Features: Good conductivity and corrosion resistance, but lower strength.
Applications: Electronic connectors, electrical switches, precision instruments.
Special Design Types
Variable Stiffness Tension Springs
Features: By varying the coil diameter or pitch, tension can be varied nonlinearly with elongation.
Applications: Automotive suspension systems, shock absorbers.
Compound Tension Springs
Features: Combined tension and compression functions, or integrated sensors for status monitoring.
Applications: Smart devices, robotic joints.
3D Printed Tension Springs
Features: Complex shapes can be achieved through additive manufacturing, breaking through the limitations of traditional winding processes.
Selection Recommendations
Based on load requirements: Select a spring with a suitable stiffness (k value) to avoid overload or insufficient elasticity.
Considering space constraints: Prefer flat or conical springs to save space.
Environmental adaptability: Special material treatment is required for high-temperature, corrosive, or magnetic environments.
Lifespan requirements: Select alloy steel or surface-hardened springs for high cycle life.
