Does a small gear driving a large gear reduce or increase speed?
2 Answers
A small gear driving a large gear reduces speed. More details about a small gear driving a large gear are as follows: 1. The rotation speed of a small gear driving a large gear will slow down, which is based on the principle of gear ratio: when two gears with different diameters mesh together, the larger gear will rotate slower than the smaller one. The speed ratio is inversely proportional to the gear diameter. 2. A small gear driving a large gear reduces speed and increases torque: Conversely, if a large gear drives a small gear, the torque decreases while the speed increases, provided that the large gear has sufficient torque. A slower speed outputs greater force, while a faster speed outputs less force. When power is constant, speed and force are inversely proportional.
When a small gear drives a large gear, it actually results in a reduction in speed. Think about it—I've been repairing cars for many years and often come across this type of gear setup, such as in a car's transmission where a small input shaft gear meshes with a larger output shaft gear. When rotating, the larger gear, due to having more teeth, turns more slowly. This is mainly because the gear ratio determines the speed ratio: the small gear rotates faster, but when driving the larger gear, the force increases while the speed decreases. This design is common in automobiles, such as in the drivetrain where speed needs to be reduced to increase torque, aiding in climbing hills or towing heavy loads. I've seen many novice drivers mistakenly believe it accelerates, but it's actually the opposite—a large gear driving a small gear is what increases speed. The benefit of reduction is improved vehicle efficiency and reduced component wear. Overall, remembering this rule helps avoid excessive engine load and ensures driving safety.
