There are various types of automotive gears based on differe

Classification according to transmission mode

• Cylindrical gears
  • Straight-toothed cylindrical gear: its tooth line is a straight line parallel to the gear axis. When this kind of gear transmits power, the tooth contact is carried out along the whole tooth width at the same time, so it will produce large shock and vibration in the transmission process, but its manufacturing process is relatively simple. For example, in some old cars in the manual transmission of the low-speed gears may be used in the straight-toothed cylindrical gears, because the low-speed gears on the transmission of the smoothness of the relatively low requirements.
  • Helical Cylindrical Gear: The tooth line is a helix, which is inclined at an angle to the axis. Compared with straight cylindrical gears, helical cylindrical gears are gradually entering and exiting the meshing of tooth surfaces in the transmission process, so it has a higher load carrying capacity, a smoother transmission, and relatively less noise. In the high-speed gears of automobile transmissions, in order to ensure smooth transmission at higher speeds, often use helical cylindrical gears.
  • Herringbone Cylindrical Gear: It is equivalent to two helical angle of equal size and opposite direction of the helical cylindrical gear and together. This gear has both the advantages of helical cylindrical gears, and because the axial force on both sides cancels each other, making the gear in the working process of axial force is very small, suitable for high-power transmission occasions, but its manufacturing process is more complicated. Herringbone cylindrical gears may be used in the main gearboxes of some heavy vehicles.
• Bevel Gear
  • Straight-tooth bevel gear: its tooth line is part of the conical bus, the gear teeth are distributed in the cone. It is used for transmission between intersecting shafts. The angle between the two shafts can be determined according to the actual needs, commonly 90°. In the differential of a car, straight-toothed bevel gears are used to transfer power from the main gearbox to the left and right half-shafts to achieve different rotation speeds of the left and right wheels.
  • Helical Bevel Gear: The tooth line is a spiral line on the cone surface, its transmission characteristics are similar to those of helical cylindrical gears, with a smoother transmission and higher load carrying capacity. However, its design and manufacture is relatively complex, in the automobile is not as widely used as straight-toothed bevel gears.
  • Curved tooth bevel gear (hypoid gear): its tooth line is a complex curve, the characteristics of this gear is to achieve a larger transmission ratio, and can make the car's drive shaft position is lower, is conducive to lowering the car's centre of gravity, thereby improving the stability of the car's driving. It is widely used in the main gearboxes of modern automobiles, especially the main gearboxes of rear-drive automobiles.

Classification by use

• Transmission Gear
  • Mainly used to change the driving speed and torque of the car. In manual transmissions, different gear combinations can achieve different ratios. For example, in the first gear, the pinion drives the large gear to achieve a larger torque output, which is suitable for the car to start; while in the high gear, the large gear drives the small gear, and the car can be driven at a higher speed. The gears in an automatic transmission also play a role in changing speed, only that its gear-shifting process is realised through a complex hydraulic system or electronic control system.
• Differential Gears
  • The differential is an important part of a vehicle's transmission system, enabling the left and right wheels to rotate at different speeds when turning corners or travelling in different road conditions. The planetary gears and half-axle gears in the differential work together to ensure that when the outer wheels are faster than the inner wheels during a turn, the differential gears automatically adjust the torque distribution between the two wheels to ensure the smooth turning of the vehicle.
• Main Reducer Gear
  • Its main function is to further decelerate and increase the torque of the power output from the transmission, and then transfer it to the differential. The main reducer gear usually adopts bevel gears, which can change the direction of power transmission in the process of transmission and provide suitable transmission ratio according to the design requirements of the vehicle to meet the power performance and driving requirements of the vehicle.