There are three types of cylindrical coil springs depending on the force nature:
1. Cylindrical coil compression spring.
1) The spacing of the springs.
The pitch for the spring is p; the diameter of the spring wire is d; and there should be an appropriate spacing between the rings in a free state. In order to allow the spring to maintain a certain elasticity after compression, it should also be ensured that under the action of the maximum load, there is still a certain spacing between the rings. The size of the 1 is generally recommended as: 1 s 1 s 0.1d s 0.2mm.
2) Dead Circle.
The two end faces of the spring are tight with the adjacent ring (no gap), only act inglising, do not participate in deformation, so it is called the dead ring. When the number of working rings of the spring n,9, the dead circle at each end of the spring is about 0.75 laps, and at n.7, the dead circle at each end is about 1 to 1.75 laps.
3) End structure form.
YI type: both end doughnuts are tight with the adjacent ring, and in the special grinding bed flat;
YII type: when heating winding the spring wire both ends forged flat and tight with the adjacent ring (end face ring can be grinding flat, can also not grind flat);
YIII type: both end sills are closely tied with the adjacent ring.
In important occasions, the YI type should be used to ensure that the two bearing end faces are perpendicular to the axis of the spring, so that the spring is not skewed when pressed. When the diameter of the spring wire d is 0.5mm, the two bearing end faces of the spring do not have to be leveled. A spring of 0.5mm, and two bearing end faces need to be leveled. The leveled part shall not be less than 3/4 of the circumference. The end thickness is generally not less than d/8, the end surface roughness should be lower.
2. The cylindrical coil stretch spring.
1) End hook type.
The stretch spring is made with hooks at both ends in order to facilitate the joint, fixation and loading.
LI type and LII type hook manufacturing is convenient, the application is very wide. However, due to the large bending stress generated at the hook transition, it should only be used in spring springs with a diameter of the spring wire d-l0mm.
LVII, LVIII type hook is not integrated with the spring wire, so there is no shortcomings of the aforementioned transition, and this hook can be transferred to any direction, easy to install. In the case of greater force, it is best to use LVII type hook, but it is more expensive.
2) Stretch ingle springs with pre-stressed.
When the cylindrical coil stretch spring is empty, the rings should be held together. In addition, in order to save axial working space, and to ensure that the spring in the empty load when the circles press each other, often in the process of winding, while the spring wire around its own axis to produce a twist. This kind of spring, each circle has a certain pressure force between each other, the spring wire also produced a certain pre-stress, so called. This spring must be in the additional pull greater than the initial pull F0, the laps began to separate, so the longer unstressed stretch spring to save the axial working space.
3, the coil twist inge spring.
Torsion alt-spring, for ease of joining, fixing and loading, has a rod arm at both ends.