Development of spring processing technology, design and materials:
Automobile springs are mainly developed in the direction of high strength to reduce quality; electronic product springs are mainly developed in the direction of smaller shape; and optical device springs are mainly developed in the direction of both high strength and small shape. Corresponding spring design methods, materials and There have been developments in processing technology and other aspects.
In electromechanical products, there are three main types of springs with the largest amount:
A) Motor vehicle springs based on automobiles;
B) Electronic product springs based on household appliances;
C) Optical device springs mainly for video cameras, copiers and cameras.
One, the development of spring design
At present, the widely used spring stress and deformation calculation formulas are derived based on material mechanics. Without certain practical experience, it is difficult to design and manufacture high-precision springs. With the increase of design stress, many previous experiences are not Reapplicable. For example, after the design stress of the spring is increased, the helix angle increases, which will cause the fatigue source of the spring to be transferred from the inner side of the coil to the outer side. For this reason, sophisticated analytical techniques must be used, and the current widely used methods are limited Meta method (FEM).
The characteristics of vehicle suspension springs are that in addition to sufficient fatigue life, their permanent deformation must be small, that is, the relaxation resistance must be within the specified range, otherwise the center of gravity of the vehicle body will be shifted. At the same time, environmental corrosion must be considered for its fatigue life Impact. With the increase of vehicle maintenance period, more stringent requirements are put forward for permanent deformation and fatigue life. For this reason, high-precision design methods must be adopted. The finite element method can predict in detail the effect of spring stress on fatigue life and permanent deformation. The influence can accurately reflect the relationship between the material’s fatigue life and permanent deformation of the spring.
In recent years, the finite element method design method of spring has entered the practical stage, and there have been many reports of practical value, such as the effect of helix angle on spring stress; the relationship between stress and fatigue life calculated by finite element method, etc.
In addition, optimization design has been 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 saved. Therefore, the designer has long used analytical methods, graphic methods or graphic analysis methods to find the best The optimal design scheme has 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 adopted to ensure the reliability of the designed product. Its task is to make the designed product reach the specified reliability target on the basis of predicting and preventing the possible failure of the product. Value. It is a supplement and improvement to the traditional design method. Spring design has made certain progress in the use of reliability technology, but further improvement requires the development and accumulation of data.
With the development of spring application technology, designers have also put forward many new problems that need to be paid attention to and solved. For example, the influence of materials, strong pressure and shot peening on fatigue performance and relaxation performance is difficult to calculate accurately during design; it depends on experimental data. To determine; another example is the number of turns calculated according to the current design formula, the stiffness of the made spring is smaller than the design stiffness value, and the effective number of turns needs to be reduced to meet the design requirements.