The current situation of the development of the spring technology

 In the mechanical and electrical products, spring variety, mainly has the following types.

1) in automobile, motorcycle, gasoline and diesel engines. The supporting spring andspring repair. This kind of spring valve spring, spring, damping spring, clutch spring, a larger amount, accounting for about 50% of the amount of spring production. At the same time, technical level is high, can be said that the technical level of these springs are representative, they are mainly to high fatigue life and high anti relaxation direction, so as to reduce the quality of.

2) large spring and a plate spring for railway locomotive vehicle, truck and construction machinery, the spring coil forming, is an important aspect of spring manufacturing. With the rapid development of high-speed railway, vehicle damping system upgrade, as hot spring forming technology of vehicle suspension has greatly improved, this kind of spring is mainlyto the high strength and high precision direction in order to stabilize the product quality.

3) spring in electronic instruments, typical products such as motor brush spring, spring,spring switch cameras and camera, and computer accessories, instrument fittings springspring. This kind of spring in spring, straight spring accounted for a large proportion,different products of different materials and technical requirements. This kind of spring at both high strength and miniaturization.

4) hardware spring to daily mechanical and electrical based, such as mattresses, sofas,door hinge, toys, lighter, this kind of spring greater demand, but the technical content is not high, to the spring small enterprises improve the opportunities for development, this kind of spring is mainly to develop towards miniaturization direction.

5) to meet the special needs of special spring mainly, such as textile machinery springs,require a high anti relaxation property; ladle sliding nozzle with the spring, has high heat resistance; suspension spring vibration sieve, it not only requires the fatigue property of high, and require a high resistance to corrosion, the rubber metal composite spring: in order to meet the comfort when the vehicle is running, the air spring.

For a specific section of suspension spring and valve spring at present, lightweight, space saving, increase comfort and improve the stress distribution of spring, spring is more reasonable than the circular cross section, but this kind of spring material prices high,spring manufacturing process is complex, the spring is higher than that of circular cross section of the spring. Therefore, there is no indication that the specific section of the springspring instead of circular cross section.

The development of the 1 spring design

At present, the spring is widely used in the stress and deformation calculation formula isderived according to the mechanics of materials. If there is no actual experience, it is difficult to design and manufacture of the spring with high accuracy, with the design stress increase, a lot of experience of the past is no longer applicable. For example, spring designstress increase, the helix angle increases, the fatigue source inside the coil spring is transferred to the outside. Therefore, must use the analytical technology of precisionsprings, the current widely used method is the finite element method (FEM).

The characteristics of vehicle suspension spring in the fatigue life is enough, thepermanent deformation is small, the relaxation resistance should be within the scope of the provisions, or due to the different deformation of the spring, the body center of gravity shift.At the same time, to consider the effect of corrosive environment on the fatigue life. With the increase of vehicle maintenance period, puts forward more strict requirements on thepermanent deformation and fatigue life, so we must adopt the design method of high accuracy. The finite element method can predict the spring effect of stress fatigue life and permanent deformation, can accurately reflect the relationship between fatigue life and thematerial of the permanent deformation.

In recent years, the finite element design method of spring has entered the practical stage,there has been a lot of practical value, such as the impact of the helix angle on the springstress; finite element method is used to calculate the stress and fatigue life of therelationship.

Is shown in Figure 1-8 is calculated by the current design method and finite element method analysis of stress. The spring of the same structure, under the same load, it can be seen from the figure, less effective circle or spiral angle high stress spring, the results from the two methods is quite different. This is because with the helix angle increases, increase the load eccentricity, the outside diameter of the spring or the lateral deformation is large,so the stress is relatively large. The calculation method can not be used to accurately reflect the current design, and the finite element method can more accurately reflect.

The finite element analysis method in the spring, spring high technical level of country hasentered the practical, though China has the technology development in this area, but has not yet formed a utility model.

In addition, in the design process of the spring was introduced for optimization design.Spring structure is relatively simple, single function, affect the structure and performanceparameters, so the designer of the early use of analytical method, graphic method andgraphic method for finding the optimal design, and have achieved some results. Along with the development of computer technology, using computer to design optimization ofnonlinear programming to achieve the results (see Chapter tenth verse 11).

Reliability design is to guarantee the reliability design of products and the use of a series ofanalysis and design technology, its function is the basis of prediction and prevention offailure may be in the product, the product to achieve the reliability target specified value, isa kind of supplement and improvement of traditional design method. The design of springhas made some progress in the use of Reliability Technology (see Chapter tenth verse 12), but the need to further improve the development and accumulation of data.