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High-precision design function and future trend of hardware spring

    With the rapid development of modern society, the development and renewal of industrialization is getting faster and faster. In the hardware spring industry, the widely used hardware spring stress and deformation calculation formulas are derived from the mechanics of materials. The production of such high-precision design springs requires certain practical experience, but with the development of social industrialization and the improvement of design applications, some previous production experience is no longer suitable for the increasingly sophisticated spring industry.
    The spring finite element analysis method has been put into practical use in countries with higher spring technology. Although my country has developed this technology, it has not yet formed a practical model. In addition, an optimized design was introduced in the design process of the spring. The structure of the spring is relatively simple, the function is simple, and the parameters that affect the structure and performance are few. Therefore, the designer used the analytical method, the graphic method or the graphic analysis method to find the optimal design solution very early, and achieved certain results. With the development of computing technology, the use of computers to optimize the design of nonlinear programming has achieved results. Reliability design is a series of analysis and design techniques used to ensure the reliability of the designed product. Its function is to predict and prevent On the basis of possible product failures, making the designed product reach the specified reliability target value is a supplement and improvement to the traditional design method.
    If the production mode of high-precision design of hardware springs is refined, after the design stress of hardware springs increases, the helix angle increases, which will transfer the source of fatigue of the spring from the inside of the coil to the outside. For this reason, it is necessary to adopt the precise analytical technique of the spring, and the current widely used method is the finite element method. The characteristics of vehicle suspension springs are that in addition to sufficient fatigue life, their permanent deformation should be small, that is, the anti-relaxation performance should be within the specified range, otherwise, due to the different deformation of the spring, the center of gravity of the vehicle will deviate. At the same time, the impact of environmental corrosion on its fatigue life should be considered. With the increase of vehicle maintenance period, more stringent requirements are put forward for permanent deformation and fatigue life. Therefore, high-precision design methods must be adopted. The finite element method can predict in detail the influence of spring stress fatigue life and permanent deformation, and can accurately reflect the relationship of materials to spring fatigue life and permanent deformation.
    Spring design has made some progress in the use of reliability technology, but further improvement requires data development and accumulation. With the development of computer technology, various versions of spring design programs have been compiled at home and abroad to provide hardware spring technicians with convenient conditions for development and innovation. The application design program has completed the development of arc-shaped clutch springs and drum-shaped suspension springs that are difficult to design. With the development of spring application technology, many new problems that need to be paid attention to and solved have also been raised for designers. For example, the influence of materials, strong pressure and shot peening on fatigue performance and relaxation performance is difficult to calculate accurately during design, and it depends on experimental data. Another example is the number of turns calculated according to the current design formula, the stiffness of the springs made is smaller than the design stiffness value, and the effective number of turns needs to be reduced to meet the design requirements. The current design trend of mass-produced products takes the maximum working shear stress and fatigue life requirements as examples.
    In recent years, the finite element design method of springs has entered the practical stage, and many reports with practical value have appeared, such as the influence of helix angle on spring stress; the relationship between stress and fatigue life calculated by finite element method. Shown is the comparison of the calculated stress with the current design method and the finite element method. For springs of the same structure, under the same load, it can be seen from the figure that the stresses of high-stress springs with fewer effective loops or large helix angles are quite different in the results obtained by the two methods. This is because as the helix angle increases, the load eccentricity is increased, and the outer diameter or lateral deformation of the spring is larger, so the stress is larger. The current design calculation method cannot accurately reflect it, but the finite element method can reflect it more accurately.