A fixed ratio transmission is a type of transmission system designed to maintain a constant, unchanging relationship between the speed of its input and output shafts.
Understanding Fixed Ratio Transmissions
Based on the reference, fixed ratio transmissions are among the simplest transmissions used. Their fundamental purpose is to provide a consistent change in speed from the input to the output. This change can manifest in two primary ways:
- Gear Reduction: The output shaft rotates slower than the input shaft, typically increasing torque.
- Speed Increase: The output shaft rotates faster than the input shaft, typically decreasing torque.
The defining characteristic is the "fixed ratio," meaning the gear ratio (the relationship between the number of teeth on the gears or the relative sizes of the rotating components) is constant. Once the transmission is built, this ratio does not change.
Key Functions
As stated in the reference, fixed ratio transmissions can perform these functions:
- Provide a gear reduction.
- Provide a speed increase.
- Sometimes, in conjunction with the speed change, they can facilitate a change in the orientation of the output shaft. This is common when using bevel gears or worm gears.
Where Are They Used?
The reference provides specific examples of applications where fixed ratio transmissions are utilized:
- Helicopters: Used within the gearbox to connect the engine(s) to the rotor system, providing necessary speed reduction and often changing the shaft orientation.
- Wind Turbines: Employed in the gearbox to increase the slow rotational speed of the turbine blades to a much higher speed required to drive the generator efficiently.
These examples highlight the reliability and consistent performance needed in critical machinery, which fixed ratio transmissions provide due to their simple and robust design.
