1. Cylindrical gear drive
For the transmission between parallel shafts, the general transmission ratio of single stage up to 8, maximum 20, two stage up to 45, maximum 60, three stage up to 200, maximum 300. The transmission power can reach 100,000 kW, the speed can reach 100,000 RPM, the circumferential speed can reach 300 m/s. The single-stage efficiency is 0.96 ~ 0.99. Spur gear drive is suitable for medium and low speed drive. Helical gear transmission runs smoothly and is suitable for medium and high speed transmission. Herringbone gear transmission is suitable for transmission of high power and large torque. There are three meshing forms of cylindrical gear transmission: external meshing gear transmission, by two external gear meshing, the two wheels turn opposite; An internal gear drive, consisting of an inner gear meshing with a small outer gear, with the same steering of the two wheels; Rack and pinion drive, which changes the rotation of gears into straight line movement of the rack, or vice versa.
2. Bevel gear drive
Used for transmission between intersecting shafts.Single-stage transmission ratio can be up to 6, the maximum to 8, transmission efficiency is generally 0.94 ~ 0.98. Straight bevel gear transmission power up to 370 kW, circumferential speed 5 m/s. Helical bevel gear drive runs smoothly and has high load carrying capacity, but it is difficult to manufacture and less used. The curved bevel gear drive runs smoothly, the transmission power can reach 3700 kW, the circumferential speed can reach more than 40 m/s.
3. Hyperboloid gear drive
Used for transmission between staggered shafts.Single-stage transmission ratio can be up to 10, maximum to 100, transmission power can be up to 750 kW, transmission efficiency is generally 0.9 ~ 0.98, circular speed can be up to 30 m/s. Because of the axis offset, pinion cantilever mounting can be avoided. Widely used in automobile and tractor transmission.
4.Helical gear drive
Used for staggered transmission, transmission ratio can be up to 5, low bearing capacity, serious wear, few applications.
The main form of staggered shaft drive, the axis of the staggered Angle is generally 90℃. Worm drive can obtain a large transmission ratio,usually a single stage of 8 ~ 80, for the transmission of movement can be up to 1500; Transmission power up to 4500 kW; Worm speed up to 30,000 RPM; Circular speed up to 70 m/s. Worm transmission works smoothly, transmission ratio is accurate and can be self-locked, but the transmission efficiency is lower than 0.5 when self-locked.The sliding between tooth surfaces of worm transmission is large, the heat is more, and the transmission efficiency is low, usually 0.45 ~ 0.97.
6. Arc gear drive
Gear transmission with convex and concave arc tooth profile. When there is no load, the two tooth profiles are in point contact, and the contact points move along the axis direction in the meshing process, and the continuous transmission is obtained by the longitudinal contact degree greater than 1. Features are high contact strength and bearing capacity, easy to form oil film, no root cutting phenomenon, uniform tooth wear, good running performance; But it is very sensitive to the errors of center distance, cutting depth and spiral Angle, so it requires high precision of manufacturing and installation.
7.Cycloid gear drive
Gear transmission with cycloid tooth profile. This kind of transmission tooth surface contact stress is small, wear resistance is good, no root cutting phenomenon, but the manufacturing accuracy is high, the center distance error is very sensitive. Only used in clocks and gauges.
8. Planetary gearing
A gear drive with a moving axis. There are many types of planetary gear transmission, and the performance of different types varies greatly. It is very important to choose the type reasonably according to the working conditions. Commonly used by the sun wheel, planetary wheel, inner gear and planetary frame composed of ordinary planetary transmission, less tooth difference planetary gear transmission, cycloid pin wheel transmission and harmonic transmission. Planetary gear transmission is generally composed of parallel shaft gears, with the characteristics of small size and light weight, input shaft and output shaft can be in the same straight line.