What are the characteristics and design principles of spring machine open mold springs:
In recent years, with the development of mold industry, the number and variety of mold springs, especially the special cross – section steel mold springs, are increasing. The special – shape dissection mold spring spring has the characteristics of large stiffness, long life and small volume. But the development of its design theory is slow. At present, in addition to the square cross-section strong spring design method is more mature, other cross-section strong spring design method, basically according to the specific cross-section through test, find out the correction coefficient to get a specific cross-section of the experience design formula, is a brief introduction to the characteristics of the spring and design problems.
The problem is that the person using this spring is very concerned and must be clear about the problem. The following is compared with the square section and the circular – section coil spring.
In the same space, the carrying capacity of the square cross-section wire spring is 43-48% higher than the circular section reed. Obviously, the rectangular reed is greater than 50%.
From the analysis that excessive use of stress is the main cause of spring damage, under the same conditions, the life of the hetero-sectional steel spring is 13-14% higher than that of the circular cross-section steel spring.
The special – shaped – section wire spring can produce a large amount of deformation.
The weight of the shaped wire spring is large.
Linearity is better than a circular – section spring, i.e. stiffness tends to be more constant. In particular, long edges parallel to the axis of the spring.
(1) The scope of application is limited by a certain degree: from the analysis can be seen, if the hetero-section material spring can not fully apply its advantages, it will not produce economic benefits, under what circumstances good use?
First, the use of circular cross – section material can not reach the design load.
Second, replace the circular cross – section composite spring.
Third, with round material spring can not reach the required amount of deformation.
Four, spring installation space is small place.
V. Require spout characteristics strict place.
2, mold spring design principles.
One. The selection of spring materials with stress should be considered in order to ensure the life of spring fatigue. The dynamic life of a spring is generally divided into three categories:
Category a: 106 times the load is subjected to the intersecting;
Category b: 103-105 times the frequency of the load;
Class c: less than 103 times the frequency of the load of the interchange;
Ii. Material thickness ratio (a/b) should not be too large, and spring rotation should not be too small.
III. When designing a non-rectangular heterogeneous cross-sectional spring, it is important to derive and draw curves or calculation formulas for different rotation ratios, different aspect ratios and deformation correction coefficients (t), and cut stress correction coefficients (betas).
Four. According to the given conditions and limitations, choose the calculation of simple and parameters to choose a reasonable design method.
(3) There are still problems.
One. The low degree of standardization of mold design limits the development speed of standardized mold springs.
Two. Mold spring standardization is low, in addition to my QC7111-7113 standard for the automotive industry in the country has no formal use of national standards or industry standards, mold designers no standard seq.e. is urgent to solve the problem.
Three. The design theory is not perfect, the current more mature is the rectangular cross – section spiral spring, but its tolerance selection has not been conclusive. Its heterogenous – section spiral springs are based on rectangular cross – section and corrected by experiment.
Four. There is no special – shape dissoced material production fixed-point plant, especially no such material oil quenching tempering steel supply manufacturers. And by the spring manufacturing plant’s own modified materials, the quality is unstable, high cost, affecting the promotion and application of such springs.
Five. There is no special reed equipment for the production of such springs. Mold with a coil spring winding ratio is generally less than 4, and the domestic reed machine is suitable for winding winding ratio of more than 4 springs.