1、 Basic classification of springs
1. According to the shape, it is classified as: coil spring (cylindrical, round hammer, drum, barrel), laminated spring, torsion bar, cylindrical, sliding coil spring, ring spring, thin plate spring, coil spring, washer (spring washer: toothed washer, wave washer), serrated spring, snap ring, etc.
2. According to the stress state of the spring material, it is divided into three categories: compression coil spring, tension coil spring and torsion coil spring.
3. Among them, compression springs and tension springs are mostly mass-produced, with complicated specifications but suitable for application with slight modification. If a small number of springs are required and the characteristics of springs are not critical, the price is easy to reach in the market. Most of the users of exclusive mechanism parts want to be customized by professional spring manufacturers. If they can't design, they can also pay extra to ask the manufacturer to cooperate with the trial production. In recent years, the industry has adopted CNC computer-controlled or mechanical spring machinery. The instrument is automatic, labor-saving and the quality is relatively stable. Based on ISO and the international demand for quality is gradually increasing. Almost all spring manufacturers can put forward the characteristic test for the spring.
2、 Nominal size of coil spring:
1. Wire diameter, the main characteristic key of coil spring is the wire diameter.
2. It is convenient to measure the outer diameter of the coil spring and easy to identify.
3. The total number of coils, the effective number of coils, the number of coils at the closed end, and the reaction force that the coil spring can bear, and the number of coils that are partially removed.
4. Pitch (lead) the variation distance on the axis of both ends of a coil spring wire.
5. Free angle: the angle value when the two legs of the torsion spring are not rotated by external force. Generally speaking, the angle formed between the two legs of the torsion spring is not easy to be the same in the free state. Unless it is required in special occasions, it is not required, or a relatively loose tolerance range is allowed.
6. Action angle: when the two ends of the torsion spring are twisted in different directions to a fixed angle, there should be reaction load force value and torsion force value, so that the matched special product can play its role.
7. The free length is the length value when no external force is applied to both ends of the tension and compression spring. In general, the free length is independent of the function of the spring, unless the two ends are closed by grinding. Otherwise, a relatively loose tolerance range or no dimensional requirements are allowed.
8. Action length: when the coil spring is compressed or stretched to its fixed length, it should have the reaction force value, so that the matching characteristics can play a role.
9. Spring constant; The reaction force generated at each unit length when the axial direction of the tension and compression spring deforms under external force or the reaction force generated at each angle when the radial direction of the torsion spring rotates under external force. In the corresponding graph with the length as the abscissa and the force as the ordinate, the intersection point hi is almost connected into a straight line.
10. The unit of length is generally mm. In Europe and America, it is customary to use inch (British style) VK load unit. The standard unit of strength is n fire, and it is customary to use KGF. If inch (British) is used as the length unit, LB pound is used as the load unit in Europe and America.
