The physical properties of the spring
First, the spring related terms
1. Outside diameter: The largest diameter of a spring coil, also known as a major diameter.
2. Inside diameter: The smallest diameter of a spring coil, also known as a diameter.
3. Pitch diameter: The average diameter of the outer diameter and inner diameter.
4. Line diameter: The diameter of the spring wire.
5. Free length: the full length of the spring when it is not subject to external forces.
6. Total coils: The number of turns of the spring from one end to the other.
7. Effective coils: The number of helical coils that can be used effectively to support the load.
8.deflection: The amount of deformation of a spring after it is subjected to an external force. Often expressed as X.
9. Spring constant (spring constant): The ratio of the load to the deformation when the spring is subjected to an external force. Often referred to as "K".
10. Spring index (spring index): The ratio of pitch diameter to wire diameter of the spring coil.
Second, the working stress of the spring
Factors that affect the size of the work stress are:
1. The spring bears the load.
2. Material composition and heat treatment.
3. The effect of vibration and impact.
4. Corrosion effect.
5. Spring surface conditions.
Third, relaxation phenomenon (latent phenomenon)
1. Temperature rise: When the temperature rises, the material will expand and soften, resulting in reduced spring limit.
2. Increased load: The load increases. If the time is too long, the spring will loosen. The spring will also produce relaxation.
Fourth, residual stress
Springs may retain some internal stress during rolling and heat treatment.
Fifth, fatigue limit
The maximum amount of material that is subject to repeated stress is still not destroyed, which is called the fatigue limit. Most of the damage is caused by fatigue. The bad surface is the biggest drawback of the spring. When the spring has flaws or cracks, it is prone to fatigue damage due to repeated stress.