The basic terminology and size calculation of gears What are its classifications



Gears are toothed mechanical parts that can mesh with each other. It is extremely widely used in mechanical transmission and the entire mechanical field. As early as 350 BC, the famous ancient Greek philosopher Aristotle recorded gears in the literature. So, what are the classifications of gears? What is the basic terminology and size calculation of gears? Today we will take a look together.

Classification of gears

There are many types of gears, and the most common classification method is based on the gear axis. Generally divided into three types: parallel axis, intersecting axis and staggered axis.

1) Parallel shaft gears: including spur gears, helical gears, internal gears, racks and helical racks, etc.

2) Intersecting shaft gears: straight bevel gears, spiral bevel gears, zero-degree bevel gears, etc.

3) Cross-axis gears: There are cross-axis helical gears, worm gears, hypoid gears, etc.

Basic terminology and size calculation of gears

Gears have a lot of unique terms and expressions of gears. In order to enable everyone to understand gears more, here are some basic gear terms that are often used.

1) The name of each part of the gear

2) The term for the size of the gear teeth is the modulus

m1, m3, m8... are called modulus 1, modulus 3, and modulus 8. Modulus is a universal term in the world. The symbols m (modulus) and numbers (mm>) are used to indicate the size of the gear teeth. The larger the number, the larger the gear teeth.

In addition, in countries that use imperial units (such as the United States), symbols (diameter pitches) and numbers (the number of gear teeth of the gear when the pitch circle diameter is 1 inch) are used to indicate the size of the gear teeth. For example: DP24, DP8, etc. There are also special naming methods that use symbols (circle section) and numbers (mm) to indicate the size of gear teeth, such as CP5 and CP10.

Multiply the modulus by the circumference ratio to get the tooth pitch (p), which is the length between two adjacent teeth.

The formula is:

p=pi ratio x modulus = πm