What is a Gearbox?

The gearbox needs to withstand the force from the wind wheel and the reaction force generated by the gear transmission, which requires that the gearbox must have sufficient rigidity to withstand the force and torque, prevent deformation, and ensure the transmission quality.

The design of the gearbox box should be in accordance with the layout arrangement of the wind turbine power transmission, processing and assembly conditions, and easy inspection and maintenance. With the rapid development of the gearbox industry, more and more industries and enterprises have used gearboxes. The spiral bevel gears and helical gears of the reducer are all made of high-quality alloy steel for carburizing and quenching.

Features

The gearbox can accelerate and decelerate, which is often referred to as a variable speed gearbox.
The transmission direction can be changed. For example, we can use two sector gears to transmit the force vertically to another rotating shaft.
The gearbox changes the torque. Under the same power conditions, the faster the gear rotates, the smaller the torque on the shaft.
It has a clutch function. We can separate the engine from the load by separating the two gears that would otherwise mesh. such as brakes, etc.
The gearbox can distribute the power. For example, we can use one engine to drive multiple slave shafts through the main shaft of the gearbox, so that one engine can drive multiple loads.

Type

According to the traditional type, it can be divided into the cylindrical gearbox, planetary gearbox and gearboxes combined with each other.
It can be divided into the single-stage gearbox and multi-stage gearbox according to the number of transmission stages.
According to the arrangement of rotation, it can be divided into unfolding gearbox, split-flow gearbox, coaxial gearbox and hybrid gearbox, etc.

Lubrication

The commonly used lubrication methods for gearboxes include gear oil lubrication, semi-fluid grease lubrication, and solid lubricant lubrication.
For better sealing, high speed, large load, and good sealing performance, gear oil can be used for lubrication.
If the seal is not good, the low speed can be lubricated with semi-fluid grease.
Molybdenum disulfide ultrafine powder can be used for lubrication on oil-free or high-temperature occasions.
The lubrication system of the gearbox is very important for the proper operation of the gearbox. Large wind turbine gearboxes must be equipped with a reliable forced lubrication
system to lubricate the gear meshing area, bearings, etc.

Insufficient lubrication accounts for a large proportion of the causes of gearbox failure. Lubricating oil temperature is related to gearbox component fatigue and the life of the entire system. Generally speaking, the maximum oil temperature of the gearbox should not exceed 80 °C during normal operation, and the temperature difference between different bearings should not exceed 15 °C. When the oil temperature is higher than 65℃, the cooling system starts to work. When the oil temperature is lower than 10℃, the lubricating oil should be heated to the predetermined temperature before starting.

In summer, because the wind turbines are in full power for a long time, coupled with direct sunlight at high altitudes, etc., the operating temperature of oil products rises beyond the set value. While in winter in the northeast severe cold region, the minimum temperature often reaches below -30 ℃, which is When the lubricating oil flow is not smooth in the lubricating pipeline, the gear and bearing are not sufficiently lubricated, which will cause the gearbox to stop at high temperature, and the tooth surface and bearing will be worn. In addition, the low temperature will also cause the viscosity of the gearbox oil to increase.

Gearbox lubricating oil has an optimal temperature range for operation. It is recommended to design a lubricating oil thermal management system for the gearbox lubricating system. When the temperature exceeds a certain value, the cooling system starts to work, and when the temperature is lower than a certain value, the heating system starts to work, and the temperature is always controlled within the optimal range. In addition, improving the quality of lubricating oil is also an important aspect that must be considered in the lubrication system. Lubricant products must have excellent low-temperature fluidity and high-temperature stability.