The Description of Gear Modulus
The modulus is the number used to measure the number of tooth sizes, which is an important factor to determine the tooth size and the basic parameters of making a gear tooth. The modulus, pitch circle, pressure angle, tooth number, tooth pitch, and so on are important parameters that constitute gears.
1. Modulus series standard is customized according to the requirements of design, manufacturing, and checking. The modulus of spur gear, helical gear, and bevel gear can refer to the standard modulus series table.
2. The customized gear uses non-standard modulus for customize planetary gearbox.
3. For gears with non-straight teeth, there is a difference between normal modulus MN, end face modulus MS, and axial modulus MX.
4. For bevel gear, the modulus can be divided into large end modulus ME, average modulus MM, And small end M1.
How to calculate the gear modulus? What is the formula?
1. The calculation formula of helical gear modulus:
A. The calculation of pitch circle DO=(tooth number Z * modulus M) / trigonometric functions COSB
B. Diameter calculation DK =((tooth number z * modulus M) / trigonometric functions COSB) + (modulus * 2)
C. Perimeter calculation Z = The diameter of pitch circle DO * PI π
Notes: the installation center distance(from the center point to the rack bottom) algorithm: installation center distance HB = (pitch circle diameter DO/2) + occlusal midline
2. The calculation formula of spur gear modulus
A. The diameter of pitch circle = tooth number Z * modulus M
B. The calculation of diameter DK = (tooth number Z * modulus M) + (modulus M*2)
C. Perimeter calculation Z = the diameter of pitch circle DO * PI * π
Notes: the installation center distance(from the center point to the rack bottom) algorithm: installation center distance HB = (pitch circle diameter DO/2) + occlusal midline
It the tooth number of gear is certain, the larger the modulus, the larger the radial dimension of the wheel; the larger the modulus, the higher and the thicker the teeth; If the modulus is certain, the larger the teeth number, the more gradual the involute. The more thickness of the addendum circle and dedendum circle. If the tooth number is certain, the larger the modulus, the larger the teeth, the stronger the ability to resist breaking. Of course, the larger the tooth blank, the larger the space size.
So, choosing gears should be based on various parameters.
3. The calculation formula of gear diameter
The diameter of addendum circle = (the tooth number + 2) * modulus
The diameter of pitch circle = the tooth number * modulus
The diameter of the dedendum circle = the diameter of the addendum circle - (4.5 * modulus)
For example M4 32 teeth 34 * 3.5
The diameter of addendum circle = (32 + 2) * 4 = 136MM
The diameter of pitch circle = 32 * 4 = 128MM
The diameter of dedendum circle = 136 - 4.5 * 4 = 118MM
7MM 12 teeth center distance D =(the diameter of pitch circle 1 + the diameter of pitch circle 2) / 2 = (12 + 2) * 7 = 98MM. This method is suitable for all the modulus gear.
4. The modulus expresses the tooth size of the gear
The gear modulus = the diameter of pitch circle / the tooth number = the outer diameter of gear /(the tooth number -2).
The Chinese standard Gear modulus
Modulus Standard Series(prior selection): 1,1.25,1.5,2,2.5,3,4,5,6,8,10,12,14,16,20,25,32,40,50.
Modulus Standard Series(you can choose): 1.75,2.25,2.75,3.5,4.5,5.5,7,9,14,18,22,28,36,45
Modulus Standard Series(you can choose): 3.25,3.75,6.5,11,30
5. The new method of calculation of the spiral angle of helical gear
Circular pitch, the diameter of the pitch circle of gear D can be expressed by modulus(M), diameter pitch(DP), circular pitch, tooth number(z). the diameter pitch refers to the tooth number on the diameter of the pitch circle. The relationship between diameter pitch and modulus: M = 25.4 / DP
CP 1/8 modulus = 25.4 / DP8 = 3.175 3.175/3.1416(π)=1.0106 modulus
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