1. Rack modulus:

Rack is a special gear with teeth distributed on the bar body, which can be divided into straight teeth and helical teeth. Rack modulus is the basic parameter of rack selection. It is the distance between two teeth, that is, the ratio of the tooth distance p between the tooth profile on the same side of two adjacent gear teeth to PI. The commonly used modules are 1.5/2 and 3/4/5/6, which can be used for 1-15 modules.

Two, rack modulus calculation:

1. Straight rack modulus algorithm:

a, modulus m= tooth spacing p/ PI PI

b, tooth distance p= modulus m* PI π

c. Midline of occlusion Ho= rack height - modulus m

2. Helical rack modulus algorithm:

a, modulus m= pitch p/ (PI π* trigonometric function cosB)

b, tooth spacing p= modulus m* (PI π* trigonometric function cosB)

c. Midline of occlusion Ho= rack height - modulus m

Note: Standard helical rack Angle 19.5283 degrees (19 degrees 31 minutes 42 seconds), trigonometric function cosB=0.9424764995.

Iii. Related characteristics of rack modulus:

1, rack modulus M is an important parameter, the modulus determines the price of the rack.

2. Module, pressure Angle and number of teeth are the three basic parameters of rack and pinion.

3. Any straight line parallel to the tooth top line has the same tooth pitch and modulus.

4, the larger the modulus, the larger the teeth, the same tooth spacing is larger.

5, the greater the modulus, the height of the rack will be higher.

6, rack and gear meshing clearance should be 0.25* modulus.

7. On the premise that the structure allows, the module M should be slightly larger, which is particularly important for the start of transmission with impact load.