This article describes the characteristics of the spring and die design principles, from the theoretical circular shaped wire die springs and wire springs of stress, stiffness, deformation is analyzed. Brief strong spring mold design, mold strong spring that influenced the development of the main problems.
Industrial development in recent years with the mold, the mold is a specially shaped wire spring in particular the application spring mold growing number and variety. Profiled die spring with stiffness, long life, small size and so on. However, relatively slow development of its design theory. Currently, in addition to strong spring square section design methods mature, the other Jiemian strong spring design, Ji Ben is Genjujuti Jiemian the experiment, Zhaochuxiuzheng specific section of Jing Yan Ji Shu derived design formulas Xian and that type of Tanhuangtedian design for a profile.
The problem is the use of such springs are very concerned about the issue must also be clear. The following section and circular cross section with square spiral spring to compare.
In the same space, the square cross-section bearing capacity of the spring steel wire spring is higher than the circular cross section 43-48%. Obviously, rectangular spring is greater than 50%.
From the use of excessive stress is the main reason for failure of the spring, under the same conditions, specially shaped steel wire spring steel wire spring than circular cross section to increase the life span of 13-14%.
Specially shaped wire springs can produce a large deformation.
The weight of large shaped wire spring.
Linearity better than round wire spring, which tends to be more stiffness constant value. Especially the long side parallel to the winding axis of the spring.
Applications subject to certain limitations: the analysis shows, specially shaped materials, such as the spring does not fully apply its advantages, it will not generate economic benefits, under what circumstances to use then?
(1) with a circular cross-section materials reach the design load.
(2) to replace the circular cross-section of composite springs.
(3) materials with a round spring deformation required to reach the time.
(Four) small spring where installation space.
(5) requires the spring characteristics of a strictly local.
2, mold spring design principles
1. Spring material allowable stress [τ] the choice should be to ensure that the fatigue life of the main spring be considered. The dynamic life of spring, generally divided into three categories:
Class Ⅰ: the number of load is 106;
Class Ⅱ: the number of the load is 103-105;
Ⅲ categories: the number of load is less than 103;
2. Material thickness to width ratio (a / b) not be too big, but not too small convolution spring.
3. Design of non-rectangular shaped cross-section spring, we must derive and draw ratio at different rotation, and deformation of different ratios of width correction factor (τ) and shear stress correction factor (β) of the curve or formula.
4. According to the given conditions and constraints, select the calculation is simple and reasonable design parameters.
Three outstanding issues
1. Low level of standardization of mold design, mold spring limited the pace of development standards.
2. Die springs with low degree of standardization, at present except for the auto industry I have developed QC7111-7113 standards for external use, there is not an official national standard or industry standard, non-standard optional mold designers are pressing problem.
3. Perfect design theory, the relatively mature spiral spring is rectangular, but its use is inconclusive tolerance. The specially shaped coil spring are rectangular-based trial, to be amended.
4. Not designated specially shaped material production plants, in particular, no such materials supplier to the oil quenched and tempered steel wire. Restructuring by the spring manufacturing their own material, unstable and high cost, impact of the popularization and application of such springs.
5. No dedicated volume production of such spring spring device. Die than with the spiral spring convolution is less than 4, while the domestic spring coiling machine for winding mold strong spring system features and design principles of 4 or more convolution than in spring.
