Toy Spring Features and Design Principles

With the development of the mold industry, the number and type of profiled wire mold springs are increasing. Profiled die springs are characterized by high stiffness, long life, and small size. However, the development of its design theory is relatively slow. At present, except for the design method of the square section strong Spring, the design methods of Other section strong springs basically pass the test according to the specific section to find out the correction coefficient to get the empirical design formula of the specific section. A brief introduction to design issues.

In the same space, the spring load capacity of square section wire springs is 43-48% higher than that of round-section springs. Obviously, the rectangular spring is more than 50%.

Excessive use of stress is the main reason for the destruction of the spring. Under the same conditions, the profiled steel wire spring has a 13-14% longer life than a round steel wire spring.

Profiled wire springs can produce large amounts of deformation.

Shaped wire springs are heavy.

The linearity is better than that of a round-section spring, that is, the stiffness tends to be a constant value. Especially springs with long sides wound parallel to the axis.

The scope of application is subject to certain restrictions: From the analysis, it can be seen that if springs of profiled cross-section materials cannot fully utilize their advantages, they will not produce economic benefits. In what circumstances can they be used well?

(1) The design load cannot be achieved with circular cross-section material.

(2) Replace the round cross-section composite spring.

(3) When the required amount of deformation cannot be achieved with the round material spring.

(4) Where the spring is installed in a small space.

(5) Where strict spring characteristics are required.

Second, mold spring design principles 1. The choice of spring material allowable stress [Ï„] should be considered to ensure the fatigue life of the spring. The dynamic life of springs is generally divided into three categories:

Class I: the number of alternating loads is 106; II: the number of alternating loads is 103-105; III: the number of alternating loads is less than 103;

2. The material aspect ratio (a/b) should not be too large, and the spring should not be too small.

3. When designing non-rectangular profiled cross-section springs, it is necessary to derive and plot curves or calculation formulas for different rotation ratios, different aspect ratios and deformation correction factors (τ) and shear stress correction factors (β).

4. According to given conditions and constraints, choose a design method that is easy to calculate and a reasonable choice of parameters.

Three remaining problems 1. The low degree of standardization of mold design limits the development speed of standardized mold springs.

2. The mold spring has a low degree of standardization. At present, there is no national standard or industry standard that has been formally used in China except for QC7111-7113, which was established by the automobile industry. The lack of standard for mold designers is an urgent problem to be solved.

3. The design theory is not perfect. At present, the rectangular coil spring is more mature, but the selection of its tolerance has not been determined. Its profiled coil springs are based on rectangular sections and have been modified by experiment.

4. There are no fixed-point plants for the production of profiled cross-section materials, especially oil-quenched and tempered wire feeders without such materials. The materials manufactured by the spring manufacturing plant itself are of unstable quality and high cost, affecting the popularization and application of such springs.

5. There is no special coil spring device for producing such a spring. The helical spring coiling ratio of the die is generally less than 4, while the domestic coil spring machine is suitable for springs with a winding ratio of more than four.