Gear is the main body of power transmission. Gear transmission is the most widely used transmission form in mechanical equipment. Its main feature is that it has high efficiency and can realize high-power mechanical power transmission; The transmission is accurate and reliable, which can realize the power transmission between the two spatial shafts; With compact structure and wide application range, it is widely used in aviation, automobile, shipbuilding, mining, instrument, agricultural machinery and other industries. Therefore, gear plays a very important role in mechanical transmission, and gear manufacturing industry is also the top priority in the mechanical industry.
| a.Spur gear |
| b.Helical cylindrical gear |
| c.Herringbone cylindrical gear |
| d.Internal meshing cylindrical gear |
| e.Rack and pinion |
| f.Spur gear |
| g.Spiral bevel gear |
| h.Crossed helical gear |
| i.Worm gear |
According to the working conditions of gear transmission (motion form, transmission shaft position and steering), gear transmission can be divided into the following basic types, as shown in the table.
One of the basic requirements of gear transmission is to ensure that the instantaneous transmission ratio in gear transmission remains unchanged in order to reduce the inertial force, so as to achieve the smooth transmission of gears. There are many curves that can meet this basic requirement and form the gear profile, but considering the requirements of design, manufacturing, installation and use, the commonly used tooth profile curves include involute, cycloid, arc and so on. Among them, involute gear is the most widely used, and the gears of automobile speed change box are mostly involute straight teeth or helical teeth.