# NEWS CENTER # How to Calculate the Gear Modulus

2022-11-10

#### How to Calculate the Gear Modulus:

What is the gear modulus? How to calculate? What is the calculation formula? For friends who are new to gear processing, it may not be very clear. Next, the gear processing manufacturer Dairuike Electromechanical laser chuck will share with you the calculation formula of the gear modulus for reference.

#### 1. What is the gear modulus?

The gear modulus is an artificially abstracted number used to measure the scale of the gear teeth. It is a factor that determines the size of the teeth and is one of the most basic parameters for gear teeth. Several important parameters of gear products are composed of gear module, pitch circle, pressure angle, number of teeth, and tooth pitch.
1. Modulus series standards are formulated according to the requirements of design, manufacture and inspection. For the modules of straight teeth, helical teeth and bevel gears, please refer to the standard module series table.
2. Many customized mass-produced gears use non-standard modules.
3. For gears with non-straight teeth, the modulus has the difference between the normal modulus mn, the end face modulus ms and the axial modulus mx, and they are based on their respective pitches (normal pitch, end face pitch and The ratio of axial pitch) to pi is also in millimeters.
4. For bevel gears, the modulus is divided into big end modulus me, average modulus mm and small end modulus m1.

#### 2. How to calculate the gear modulus? What is the gear modulus calculation formula?

##### 1. Calculation formula of helical gear modulus:

a. Calculation of pitch circle diameter Do=(number of teeth Z*modulus m)/trigonometric function cosB
b. Diameter calculation Dk=((number of teeth Z*modulus m)/trigonometric function cosB)+(modulus m*2)
c. Calculation of the circumference of one revolution of the gear Z=diameter of the indexing circle Do*circumference π
Note: Algorithm of the installation center distance from the gear center point to the bottom surface of the rack: installation center distance Hb=(diameter of pitch circle Do/2)+occlusal center line Ho.

##### 2. Calculation formula of spur gear modulus:

a. Pitch circle diameter technology Do=number of teeth Z*modulus m
b. Diameter calculation Dk=(number of teeth Z*modulus m)+(modulus m*2)
c. Calculation of the circumference of one revolution of the gear Z=diameter of the indexing circle Do*circumference π
Note: Algorithm of the installation center distance from the gear center point to the bottom surface of the rack: installation center distance Hb=(diameter of pitch circle Do/2)+occlusal center line Ho. If the gear has a certain number of teeth, the larger the modulus, the larger the radial size of the wheel; the larger the modulus, the higher and thicker the teeth; if the modulus is constant, the larger the number of teeth, the smoother the involute , the thickness of the top round tooth and the dedendum round tooth thickness are correspondingly thicker; when the number of teeth is constant, the larger the modulus, the larger the tooth, the stronger the ability to resist breaking, and of course the larger the gear blank. The larger the size of the space.
Therefore, when selecting gear processing products, it is necessary to comprehensively consider various parameters, and select laser chucks with appropriate models and specifications according to the needs of actual applications.