The types of gearbox gears mainly depend on the following factors:

1. Transmission type: Different types of transmissions (such as manual transmission, automatic transmission, CVT continuously variable transmission, dual clutch transmission, etc.) will use different types of gears to adapt to their specific transmission requirements and operating mechanisms.

2. Transmission ratio: The number and size of teeth on the gear determine the transmission ratio. According to the design and performance requirements of the vehicle, the gearbox will be equipped with gears of different numbers of teeth to achieve the required transmission ratio, in order to meet the power transmission needs under different speed and load conditions.

3. Shifting method: Manual transmissions typically use sliding gears and synchronizer gears to shift gears, while automatic transmissions may use planetary gear sets or clutches to achieve automatic shifting.

4. Power transmission characteristics: The shape and design of gears (such as straight teeth, helical teeth, spiral teeth) can affect their transmission efficiency and noise level. According to the performance requirements of the vehicle, different types of gears will be selected to optimize the power transmission characteristics.

5. Material selection: The material of gearbox gears (such as alloy steel, powder metallurgy, etc.) will affect their wear resistance, strength, and heat resistance. Suitable materials will be selected based on the working environment and expected service life of the gears.

6. Manufacturing process: The manufacturing process of gears (such as cutting, heat treatment, surface treatment, etc.) will affect their accuracy, surface quality, and durability. The choice of manufacturing process will affect the final performance of gears.

7. Cost and weight: The design and material selection of gears are also limited by cost and weight. When designing gearbox gears, it is necessary to find a balance between performance and cost.

8. Durability and Maintenance: The durability and maintenance requirements of gears can also affect their design. For example, some gears may require special lubrication systems or surface treatments to extend their service life.

The design of gearbox gears is a complex process that requires comprehensive consideration of the above factors to ensure that the gears can meet the performance requirements of the gearbox while maintaining reliability and economy.