## TASHIN SPRING-Basic Knowledge of Spring-Compression Spring

#### 2023-04-27

**Commonly used straight compression springs have several basic components:**

The most basic conditions and dimensions - 1. Wire diameter - d, 2. Center diameter - D, 3. Total number of turns - Nt, 4. Free length - L, 5. Wire material

Other detailed conditions-6. Number of effective turns-Na, 7. Direction of rotation, 8. Head and tail end shape

After the basic size is determined, the derived size is as follows:

a. Spring coefficient-k (average weight increase per 1mm of pressure)

b. Gap-p (effective number of turns, gap size, distance from line center point)

c. Spring index - c (that is, the ratio of center diameter D/wire diameter d, which can also be expressed as D/d). The smaller the value, the greater the force required to change the spring shape.

(The stress becomes larger) means that the harder the spring, the commonly used value between 4 ~ 22, and the value exceeds this range, there will be difficulty in forming

d. Close contact height-Hs (compress the spring to the fully compact length of the coil)

e. Spring aspect ratio - that is, the ratio of free length L/center diameter D. Commonly used values are between 0.4 and 4. If the value is too large, it will easily skew during use.

In this case, it can be improved with end grinding. If the value is too small, the number of Na-effective turns will be too few, resulting in unstable load.

Four basic dimensions - wire diameter - d, center diameter - D, total number of turns - Nt, free length - L. When a single size changes, the elastic force generated when compressed to the same length changes as follows:

Wire diameter ↑ , elasticity ↑

The increase in wire diameter is the biggest factor affecting the increase in spring elasticity, especially the change below 1.0mm. The larger the wire diameter, the smaller the influence.

Center diameter ↑ , elastic force ↓

As the center diameter (circle diameter) increases, the spring shape becomes easier to change. When compressed to the same distance, the elastic force becomes smaller.

Total number of turns ↑ , elasticity ↓

As the number of turns increases, the spacing becomes smaller under the same free length. When compressed to the same distance, the average amount of compression required per turn becomes smaller, so the elastic force becomes smaller.

Length ↑ , elasticity ↑

When the length is lengthened, the distance becomes larger when the number of turns is the same. When compressed to the same distance, the average amount of compression required per turn becomes larger, so the elastic force becomes larger.