Bevel Gearbox Noise Processing

Gearbox is one of the most important mechanical parts used in wind turbine.The main function is to transfer the power of the wind wheel to the generator and get the corresponding speed.

Generally, the speed of the wind wheel is very low, which can not reach the speed required by the generator, so it must be realized by the growth of gear box gear.

Compared with other industrial gear box, because of wind power gear box installed on dozens of meters or more than one hundred m high from ground narrow cabin, its volume and weight of the cabin, tower and foundation, the wind load of unit, installation and maintenance cost, etc all have important influence, therefore, it is particularly important to reduce the overall dimensions and weight.At the same time, due to the inconvenience of maintenance and high maintenance cost, the design life of gearbox is usually 20 years, and the requirement of reliability is extremely strict.Since size and weight and reliability are often irreconcilable contradictions, the design and manufacture of wind power gearboxes are often in a dilemma.The overall design stage should be based on the requirements of reliability and working life, and the comparison and optimization of transmission scheme is carried out with minimum volume and minimum weight.The structure design should satisfy the transmission power and space limitation as the premise, as far as possible the structure is simple, the operation is reliable, the maintenance is convenient;Ensure product quality at every link in the manufacturing process;In operation, the operation state of gear box (bearing temperature, vibration, oil temperature and quality change etc.) shall be monitored and maintained in real time according to the standard.

Since the tip linear speed cannot be too high, the rated input speed of the gearbox decreases gradually as the capacity of the unit increases, and the rated speed of the megawatt is not more than 20r/min.On the other hand, the rated speed of the generator is generally 1500 or 1800r/min, so the speed ratio of the large wind speed gearbox is about 75 ~ 100.In order to reduce the volume of gearbox, the wind speed box above 500kw usually adopts the planetary transmission of power shunt.The common structure of 500kw ~ 1000kw has 2 levels of parallel axis + 1 and parallel axis + 2 planetary transmission.The megawatt gearbox USES a 2-level parallel axis + 1 planetary drive structure.Due to the relative complexity of the planetary transmission structure and the difficulty of processing large internal gear ring, the cost is relatively high, even though the two-stage planetary transmission is used as the NW transmission

use

1. Accelerated deceleration, which is often said of gearshift gearbox.

2. Change the direction of the transmission. For example, we can pass the force perpendicular to the other axis with two fan-shaped gears.

3. Change the torque of the rotation. The faster the gear with the same power condition, the smaller the torque of the shaft, and vice versa.

4. Separation function: we can achieve the purpose of separating the engine from the load by separating the two original meshing gears, such as the brake clutch.

5. Power distribution. For example, we can use an engine to drive multiple axes from the main shaft of the gearbox to achieve the function of one engine driving multiple loads.

Noise processing

Gear box is an important part of a widely used in mechanical transmission, a pair of gear meshing, because there are inevitably, pitch and tooth profile error produces in the process of operation in the gear mesh frequency corresponding to the meshing impact and noise, the noise due to the relative sliding friction between tooth surfaces.Because gear is the basic part of gearbox transmission, it is necessary to reduce gear noise to control the noise of gearbox.Generally speaking, the noise of gear system is mainly caused by the following aspects:

1. Gear design.The parameter selection is improper, the overlap is small, the shape of the tooth profile is improper or unshaped, the gear box structure is not reasonable.In the gear machining aspect, the base pitch error and the tooth form error are too large, the tooth side clearance is too large, the surface roughness is too large.

2. Gear and gear box.Assembly eccentric, low contact accuracy, horizontal difference of shaft, shaft, bearing, bearing, bearing, low rotation precision and improper clearance.

3. Input torque in other areas.Fluctuation of load torque, torsional vibration of shafting, balance of motor and other transmission pairs.