The development of a spring design
the widely used spring stress and deformation formula Is derived according to the mechanics of materials.The absence of some of the practical experience, it is difficult to design and manufacture of high-precision spring.With the improvement of the design stress, a lot of experience in the past is no longer applicable. For example, Increase of the design stress of the spring, spiral angle increased, the the coils make spring fatigue source is transferred to the outside from the inside.To this end, using sophisticated analytical techniques, The current wider application of the method is the finite element method (FEM)
Except sufficient fatigue life characteristics of the vehicle suspension spring, the permanent deformation to be small, i.e., an anti-relaxation properties to be within a predetermined range, otherwise will occur body center of gravity offset.At the same time, we must consider the impact of environmental corrosion fatigue life,to the end, must use precision design method.The finite element method can be detailed forecast spring stress on the fatigue life and permanent deformation, can accurately reflect the relationship between the material of spring fatigue life and permanent deformation.
In recent years, the design method of the spring of the finite element method to enter the practical stage, there are a lot of practical value of the report, such as the helix angle of the impact of the stress of the spring; using the finite element method to calculate the stress and fatigue life relationship.
For the same structure of the spring, under the same load, the effective circle few or helix angle the trouble stress spring stress, and relatively large differences in the results by the two methods.This is because with increasing helix angle, in addition to the load eccentricity, so that the spring outer diameter or larger transverse deformation,thus stress is also larger. the current design calculation methods does not accurately reflect,the finite element method exactly reflected.
In addition, in the spring design process also introduced optimization design.Spring of relatively simple structure, the function simply affect the structure and performance of parametric .so designers very early use of the analytical method, graphical method or graphical analysis of law seeks the optimal design, has achieved some success. With the development of computing technology, the use of a computer for the optimal design of nonlinear programming, have achieved success.
On the basis of reliability design in order to ensure the reliability of the product design and adopted a series of analysis and design technology, its task is in the prediction and prevention of product may malfunction,So that the design of the product to achieve the required reliability target value.it is a traditional design methods to supplement and improve. Spring design in the use of reliability technology has made some progress, but it is necessary to further improve the development and accumulation of data is required.
with the spring application technology development, it also make the designers need to pay attention to and solve new problems.such as,Materials, extreme pressure and shot peening on fatigue performance and relaxation properties,The design difficult exact calculation; rely on experimental data.and Calculated at the current design formula laps,
Design made of spring stiffness than stiffness values,need to reduce the number of active coils, in order to achieve the design requirements.