Open gears are widely used for their high efficiency in transmitting power.

Definition
Gear transmission is a crucial component of mechanical transmission. It comes in various forms and is widely utilized. The transmitted power can be as high as hundreds of thousands of kilowatts, with peripheral speeds reaching up to 150m/s or even 300m/s. The diameter of gears can also be over 10 meters.
Types
There are three types of gear transmissions, namely:
- Open gear transmission
- Semi-open gear transmission
- Closed gear transmission
In the field of agriculture machinery, construction machinery, and basic mechanical equipment, some gear drives are without dust covers or casings, leaving the gears completely exposed. This type of gear transmission is referred to as an “open gear transmission.”
This open design makes it susceptible to external debris and poor lubrication, leading to adverse working conditions. Additionally, the gears are easily prone to wear, making it suitable only for low-speed transmissions.
A semi-open gear transmission, on the other hand, is one that is equipped with a simple protective cover or has its larger gear portion immersed in an oil pool. While the working conditions are improved, it still cannot prevent the intrusion of foreign objects and does not offer the best lubrication conditions.
Closed gear transmissions, also known as gearboxes, are commonly used in automobiles, machine tools, aero engines, etc. They consist of gears housed in precisely machined and tightly closed boxes. This type of transmission offers the best lubrication and protection conditions and is used in crucial applications.
Open gear transmissions are susceptible to contamination from external substances such as dust and debris, leading to abrasive wear on the gears. The lubrication requirements of an open gear are similar to that of a closed gear when covered, but require high viscosity oils, asphaltene lubricants, or greases and work effectively at low speeds.
There are three classifications of open gear oils, which include:
- Common open gear oil (CKH)
- Extreme open gear oil (CKJ)
- Solvent diluted open gear oil (CKM)