Here's how they are used and why they are essential:

1. Power Transmission: They transfer power from the engine to the wheels. The gearbox uses spiral bevel gears to reduce the speed of the engine's output shaft, increasing torque to the drive wheels.
2. Direction Change: The gearbox allows the driver to change the direction of the vehicle. Spiral bevel gears are instrumental in engaging the correct gear for forward or reverse motion.
3. Gear Ratio Variation: By changing the gear ratios, the gearbox with spiral bevel gears allows the vehicle to operate efficiently at various speeds and under different loads.
4. Smooth Operation: The spiral shape of the bevel gears helps in smooth and quiet operation, reducing noise and vibration that would otherwise be present in the powertrain.
5. Load Distribution: The spiral design helps distribute the load evenly across the gear teeth, which increases the durability and lifespan of the gears.
6. Efficient Torque Transfer: The spiral bevel gears are designed to handle high torque loads, ensuring efficient power transfer to the vehicle's wheels.
7. Axle Angle Compensation: They can accommodate the angle between the driveshaft and the wheels, which is particularly important in front-wheel drive vehicles.
8. Reliability and Longevity: Due to their robust design and material composition, spiral bevel gears contribute to the overall reliability and longevity of the gearbox.
9. Compact Design: They offer a compact solution for power transmission, which is crucial in the confined spaces of a vehicle's engine compartment.
10. Maintenance Reduction: With their durability, spiral bevel gears require less frequent maintenance compared to other types of gears, reducing long-term costs for the vehicle owner.