What is the name of the gear that is commonly referred to as the bull gear?

The gear commonly referred to as the bull gear is typically the second reduction gear. This gear serves a significant purpose in a gear train system, particularly in applications such as marine propulsion systems. The bull gear is generally responsible for providing a large reduction in speed and, consequently, an increase in torque.

In a gear reduction system, the first reduction gear usually engages with the driving component and reduces the speed to a manageable level, before handing off to the second reduction gear, which further decreases the rotational speed while increasing the torque output. This is critical for systems that require high torque at low speeds, like in propeller drives.

The main propeller gear, while integral to the operation, does not typically take the title of the bull gear. It is primarily focused on directly driving the propeller rather than functioning as a reducer in the primary gear train. Understanding the roles of these gears in relation to one another can clarify the naming conventions and roles within mechanical systems.