The number of sets of planetary gears. Since a set of planetary gears cannot meet a large transmission ratio, sometimes two or three sets are required to meet the requirements of the user for a larger gear ratio. 1) The shaft seal of the reducer whose output shaft is a half shaft is improved: belt conveyor, The output shaft of the reducer of most equipments such as screw unloading machine and impeller coal feeder is half shaft, which is convenient for modification. Disassemble the reducer, remove the coupling, take out the shaft seal end cover of the reducer, and install the frame oil seal on the outer side of the original end cover according to the size of the matching skeleton oil seal. The side with the spring is turned inward. When reloading, if the end cap is more than 35 mm from the inner end surface of the coupling, a spare oil seal can be installed on the shaft outside the end cap. Once the oil seal fails, the damaged oil seal can be taken out and the spare oil seal can be pushed into the end cover. Eliminate the time-consuming and laborious process of understanding the body reducer and dismantling the shaft. That is to say, the larger the reduction ratio, the more the number of stages/stages, and the lower the efficiency.
Composition structure:
For structural reasons, the single-stage deceleration is a minimum of 3, and the maximum is generally less than 10. The common deceleration is: 3.4.5.7.10, 15, 20, 25, 30, 35, 40, 50, 70, 80, 100. More than 3 stages of deceleration, but some large reductions have 4 levels of deceleration than custom reducers. The rated input speed of the servo planetary reducer can reach up to 18000 rpm (depending on the size of the reducer itself, the larger the reducer, the amount of KW - the operating cycle coefficient; the smaller the fixed input speed), the output torque of the industrial servo planetary reducer is generally not More than 2000Nm, the special super-torque servo planetary reducer can achieve more than 10000Nm. The working temperature is generally between -25°C and 100°C. The working temperature can be changed by changing the grease.
Gearboxes are an important mechanical component that is widely used in wind turbines. Its main function is to transmit the power generated by the wind wheel under the action of the wind to the generator and get the corresponding speed.
Usually, the speed of the wind wheel is very low, which is far from the speed required by the generator to generate electricity. It must be realized by the speed increasing action of the gear box gear pair. Therefore, the gear box is also called the speed increasing box.
The gearbox is subjected to the force from the wind wheel and the reaction force generated during the gear transmission. It must have sufficient rigidity to withstand the force and torque to prevent deformation and ensure the transmission quality. The design of the gearbox housing should be in accordance with the layout, processing and assembly conditions of the wind turbine power transmission, and easy inspection and maintenance. With the rapid development of the gearbox industry, more and more industries and different enterprises have applied gearboxes, and more and more enterprises have grown stronger in the gearbox industry.
According to the modular design principle of the unit structure, the gear box greatly reduces the types of parts and is suitable for large-scale production and flexible and variable selection. The spiral bevel gear and the helical gear of the reducer are all carburized and quenched with high-quality alloy steel. The hardness of the tooth surface is up to 60±2HRC, and the precision of the tooth surface grinding is up to 5-6.
The bearings of the transmission parts are all domestic famous brand bearings or imported bearings, and the seals are made of skeleton oil seals; the structure of the speaker body, the larger surface area of the cabinet and the large fan; the temperature rise and noise of the whole machine are reduced, and the reliability of operation is improved. The transmission power is increased. Parallel axis, orthogonal axis, vertical and horizontal universal box can be realized. The input mode includes motor coupling flange and shaft input; the output shaft can be output at right angle or horizontal level, and solid shaft and hollow shaft and flange output shaft are available. . The gearbox can meet the installation requirements of a small space, and can also be supplied according to customer requirements. Its volume is 1/2 smaller than the soft tooth reducer, the weight is reduced by half, the service life is increased by 3~4 times, and the carrying capacity is increased by 8~10 times. Widely used in printing and packaging machinery, three-dimensional garage equipment, environmental protection machinery, transportation equipment, chemical equipment, metallurgical mining equipment, steel power equipment, mixing equipment, road construction machinery, sugar industry, wind power generation, escalator elevator drive, ship field, light High-power, high-speed ratio, high-torque applications such as industrial fields, papermaking, metallurgical industry, sewage treatment, building materials industry, lifting machinery, conveyor lines, and assembly lines. It has a good cost performance and is conducive to the domestic equipment.
The gear box is an important part of the wide application in mechanical transmission. When a pair of gears mesh, there is inevitably a tooth pitch, tooth shape and other errors. During the operation, an meshing impact will occur and a noise corresponding to the gear mesh frequency will occur. Frictional noise occurs between the tooth faces due to relative sliding. Since gears are the basic part of the gearbox drive, reducing gear noise is necessary to control gearbox noise. In general, the causes of gear system noise mainly have the following aspects:
1. Gear design. Improper parameter selection, too small coincidence, improper or no shape modification, and unreasonable gearbox structure. In the gear processing, the base section error and the tooth profile error are too large, the flank clearance is too large, and the surface roughness is too large.
2. Gear train and gearbox. The assembly is eccentric, the contact precision is low, the parallelism of the shaft is poor, the rigidity of the shaft, the bearing and the support is insufficient, the rotation precision of the bearing is not high, and the gap is not appropriate.
3. Input torque in other aspects. Fluctuation of load torque, torsional vibration of the shafting, balance of the motor and other transmission pairs, etc.
The gearbox has the following functions:
1. Accelerated deceleration is the variable speed gearbox that is often said.
2. Change the direction of the drive. For example, we use two sector gears to transmit the force vertically to the other.
3. Change the turning moment. Under the same power conditions, the faster the gear rotates, the smaller the torque the shaft receives, and vice versa.
4. Clutch function: We can separate the engine from the load by separating the two originally meshed gears. Such as brake clutches.
5. Distribute power. For example, we can use one engine to drive multiple slave shafts through the gearbox main shaft, thus realizing the function of one engine to drive multiple loads.
Bearing life:
Statistics show that about 50% of faults in wind turbine gearbox failures are related to bearing selection, manufacturing, lubrication or use. At present, due to the backward technical conditions, etc., many of the core components of domestic megawatt-class units, such as motors, gearboxes, blades, electronic control equipment and yaw systems, rely on imports and are used in these large wind turbines. Box bearings, yaw bearings, pitch bearings and spindle bearings are completely dependent on imports. Therefore, the more accurate calculation method of bearing life is particularly important for the design of wind turbine gearboxes.
Due to the high reliability required for bearings, the service life of bearings is usually not less than 130,000 hours. However, due to too many factors affecting the bearing fatigue life, the bearing fatigue life theory still needs to be improved continuously. There is no uniform bearing life theory at home and abroad, which is a calculation method accepted by all industries.
The operating temperature of the bearing, the viscosity of the lubricating oil, the cleanliness and the rotational speed have a great influence on the bearing life. When the operating state is deteriorated (temperature rise, speed decrease, pollutant increase), the bearing life may be greatly reduced. In-depth analysis of various factors affecting the life of wind turbine gearbox bearings, researching a more accurate calculation method of bearing life is the top priority of the domestic bearing industry and even the wind power industry.
use:
1. Accelerated deceleration, which is often referred to as the variable speed gearbox.
2. Change the direction of the drive. For example, we can use two sector gears to transmit the force vertically to the other.
3. Change the turning moment. Under the same power condition, the faster the speed turns, the smaller the torque the shaft receives, and vice versa.
4. Clutch function: We can separate the engine from the load by separating the two originally engaged gears, such as brake clutch.
5. Distribute power. For example, we can use one engine to drive multiple slave shafts through the gearbox main shaft, thus realizing the function of one engine to drive multiple loads.
design:
Compared with other industrial gearboxes, because the wind turbine gearbox is installed in a small cabin that is several tens of meters or even more than one hundred meters high from the ground, its own volume and weight for the cabin, tower, foundation, unit wind load, installation and maintenance Costs and the like have an important impact, so it is important to reduce the size and weight. At the same time, due to inconvenient maintenance and high maintenance costs, the design life of the gearbox is usually required to be 20 years, and the reliability requirements are extremely demanding. Because size and weight and reliability are often a pair of irreconcilable contradictions, the design and manufacture of wind turbine gearboxes often fall into a dilemma. The overall design stage should meet the requirements of reliability and working life, and compare and optimize the transmission scheme with the minimum volume and minimum weight as the target; the structural design should meet the transmission power and space constraints, and consider the structure as simple as possible. Reliable operation and convenient maintenance; ensure product quality at every stage of the manufacturing process; in the operation, the gearbox operating status (bearing temperature, vibration, oil temperature and quality changes, etc.) should be monitored in real time and routinely maintained according to specifications.
Since the tip line speed cannot be too high, the rated input speed of the gearbox gradually decreases with the increase of the single unit capacity, and the rated speed of the unit above MW is generally 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 power increasing gearbox is generally around 75~100. In order to reduce the volume of the gearbox, the wind power transmission box above 500kw usually adopts the power split planetary transmission; the common structure of 500kw~1000kw has two levels of parallel axis + 1 planet and 1 parallel shaft + 2 planetary transmission. The megawatt gearbox adopts a 2-stage parallel shaft +1 planetary transmission structure. Due to the relatively complicated planetary transmission structure and the difficulty in processing large internal ring gears, the cost is high. Even with the 2-stage planetary transmission, the NW transmission is the most common.
Manufacturing Technology:
The external gear of the wind power gear box generally adopts a carburizing and quenching grinding process. The introduction of high-efficiency and high-precision CNC forming gear grinding machines has made our foreign gear finishing level not much different from that of foreign countries. There is no difficulty in achieving the 5-level precision technology specified by the 19073 standard and the 6006 standard. However, there are still gaps between China's advanced technology in heat treatment deformation control, effective layer depth control, tooth surface grinding tempering control, and gear tooth shaping technology.
Due to the large size of the ring gear of the wind turbine gearbox and the high processing precision, the manufacturing technology of the inner ring gear in China is quite different from the international advanced level, which is mainly reflected in the gear processing and heat treatment deformation control of the helical internal gear.
The machining accuracy of the structural parts such as the box body, the planet carrier and the input shaft has a very important influence on the meshing quality of the gear transmission and the bearing life. The quality of the assembly also determines the length of the wind turbine gearbox and the reliability. . China has realized from the importance of the processing and assembly precision of structural parts that there is a certain gap between the level of equipment and the advanced level of foreign countries. The acquisition of high-quality, high-reliability wind turbine gearboxes, in addition to advanced design techniques and necessary manufacturing equipment support, is inseparable from the strict quality control of every step of the manufacturing process. The 6006 standard provides strict and detailed regulations on the quality assurance of the gearbox.
Lubrication
Commonly used gearbox lubrication methods include gear oil lubrication, semi-fluid grease lubrication, and solid lubricant lubrication. For better sealing, high speed, high load, good sealing performance can be lubricated with gear oil; for poor sealing, low-speed can be lubricated with semi-fluid grease; for oil-free or high-temperature applications Molybdenum sulfide superfine powder lubrication.
The lubrication system of the gearbox is very important for the normal operation of the gearbox. The large wind turbine gearbox must be equipped with a reliable forced lubrication system to inject the oil to the gear meshing area and bearings. In the cause of the failure of the gearbox, the lack of lubrication accounted for more than half. Lubricating oil temperature is related to component fatigue and overall system life. 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 °C, the cooling system starts to work; when the oil temperature is lower than 10 °C, the oil should be heated to the predetermined temperature and then turned on.
In the summer, due to the long-term full state of the wind turbine, plus direct sunlight, the operating temperature of the oil rises above the set value; while in the cold winter in the northeast, the minimum temperature often reaches below 30 °C, lubrication. Lubricating oil in the pipeline is not smooth, gears and bearings are not fully lubricated, causing the gearbox to stop at high temperature, the tooth surface and bearing are worn out, and the low temperature will also increase the viscosity of the gearbox oil. When the oil pump starts, the load is heavy and the pump motor is overloaded. .
Gearbox lubricants have an optimum temperature range for operation. It is recommended to design a lubricant thermal management system for the gearbox lubrication system: when the temperature exceeds a certain value, the cooling system starts to work. When the temperature is lower than a certain value, the heating system starts to work. Always keep the temperature 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, and research on high-performance lubricating oil should be strengthened.
After the aluminum alloy NMRV worm gear reducer is aligned as required, it can achieve better transmission effect and longer service life. There are many types of couplings to be used, but Zui does not use steel fixed couplings. The installation of such couplings is difficult. If the installation is improper, the load will be increased, which will easily cause the bearings. Damage or even breakage of the output shaft. The fixing of the NMRV reducer is very important. To ensure smoothness and firmness, we should generally install it on a horizontal foundation or base. At the same time, the oil in the oil drain should be removed and the cooling air circulation should be smooth. The test run time of the worm gear reducer should not be less than two hours. The normal operation standard is stable operation, no vibration, no noise, no leakage, no impact. If abnormal conditions occur, it should be eliminated in time. When installing the RV geared motor, pay special attention to the alignment of the center axis of the transmission. The error of the alignment should not exceed the compensation amount of the coupling used by the reducer. If the worm gear reducer is not well fixed and the foundation is unreliable, it will cause vibration, etc., and the bearings and gears will be damaged. The transmission coupling should be equipped with guards when necessary. For example, there are protrusions on the coupling or gears, sprocket transmission, etc. If the radial load of the output bearing is large, the reinforcement type should also be used.
After the aluminum alloy NMRV worm gear reducer is installed, the accuracy of the installation position should be thoroughly checked in order, and the reliability of each fastener should be flexibly rotated after installation. If the worm gear reducer is splashed with oil pool splash, the user should remove the screw plug of the vent hole and replace it with the vent plug before running. According to different installation positions, open the oil level plug and screw, check the height of the oil level line, and add oil from the oil level plug until the oil overflows from the oil level plug screw hole. After the oil level plug is screwed up, the no-load test run can be carried out for no less than 2 hours. The operation should be stable, without impact, vibration, noise and oil leakage. If abnormalities are found, they should be eliminated in time. When installing the transmission member on the output shaft, it is not allowed to strike with a hammer. Usually, the internal friction of the assembly jig and the shaft end is used, and the transmission member is pressed by the bolt, otherwise the internal parts of the worm worm reducer may be damaged.
NMRV gearbox catalogue Download
