The Basic Functions and Working Principles of Marine Gearboxes

1. Power transmission

The main function of a marine gearbox is to receive power from the main engine (usually a diesel engine) and transmit it to the propeller efficiently. Since the speed of the main engine and the propeller is very different, the gearbox can effectively match the speed between the two to ensure smooth power transmission.

2. Adjust the speed

Since the speed of the main engine is usually much higher than the ideal speed of the propeller, the marine gearbox reduces the speed through the internal gear combination, improving the working efficiency of the propeller. In addition, by adjusting the gear ratio, the performance of the ship can be optimized under different sailing conditions.

3. Change the direction

Since the speed of the main engine is usually much higher than the ideal speed of the propeller, the marine gearbox reduces the speed through the internal gear combination, improving the working efficiency of the propeller. In addition, by adjusting the gear ratio, the performance of the ship can be optimized under different sailing conditions.

1. Power conversion

The marine gearbox converts the high speed and low torque of the input shaft into the low speed and high torque of the output shaft through the meshing of a series of gears. This process depends on the design of the gear ratio, and different gear ratios can achieve different speed and torque outputs.

2. Structural configuration

A typical marine gearbox includes input shaft, output shaft, intermediate shaft, gear, bearing, oil pump and other components. Among them, gear is the most core component. Through the combination of different gears, the required speed ratio and steering change can be achieved. For example, when driving forward, oil is added to the forward oil chamber, and the pressure plate presses the forward friction plate to the left under the oil pressure, and the power is transmitted from the left forward gear to the driven shaft downward to achieve forward driving; when driving backward, oil is added to the reverse oil chamber, and the pressure plate presses the reverse friction plate to the right under the action of oil pressure, and the power is transmitted from the right reverse gear to the driven shaft through the intermediate gear to achieve reverse driving.

1. Spur gearbox

Spur gearbox uses spur gears for power transmission, which is characterized by simple structure and low manufacturing cost. However, spur gears will generate greater noise and vibration during operation, so it is suitable for occasions with low requirements for noise and vibration.

2. Helical gearbox

Helical gearbox uses helical gears, which has lower noise and better load-bearing capacity than spur gearbox. Helical gearboxes are suitable for ships that need to run continuously for a long time and have certain requirements for noise and vibration.

3. Planetary gearbox

Planetary gearboxes use planetary gear trains to achieve power transmission, and have the characteristics of small size, light weight, and high transmission efficiency. It is particularly suitable for small and medium-sized ships with limited space.

4. Bevel gearbox

Bevel gearboxes are mainly used to change the direction of power transmission, and are often used in special occasions where vertical or inclined power transmission is required, such as some special ships or platforms.