What are the common faults and solutions for SEW reducers?
SEW reducer is a transmission machine with compact structure, large transmission ratio and self-locking function under certain conditions. Among them, the hollow shaft type worm gear reducer not only has the above characteristics, but also has convenient installation and reasonable structure, and is more and more widely used. It is equipped with a helical gear reducer at the input end of the worm gear reducer. The multi-stage reducer can achieve very low output speed, higher efficiency than single-stage worm gear reducer, and low vibration, noise and energy. Low consumption.
First, SEW reducer common problems and their causes
1. SEW reducer heat and oil leakage. In order to increase the rate, the worm gear reducer generally uses a non-ferrous metal as a worm wheel, and the worm uses a harder steel. Because it is a sliding friction transmission, more heat is generated during operation, which causes a difference in thermal expansion between the various parts of the reducer and the seal, thereby forming a gap in each mating surface, and the lubricating oil is thinned due to an increase in temperature, which is liable to cause leakage. . There are four main reasons for this situation. One is that the material is not properly matched; the other is the poor quality of the surface of the friction surface; the third is that the amount of lubricant added is not correct; the fourth is the poor quality of assembly and use.
2. Worm gear wear. The worm gear is generally made of tin bronze, and the paired worm material is hardened with 45 steel to hrc4555, or 40cr hardened hrc5055 and then ground by a worm grinder to a roughness of 0.8 μm. The reducer wears very slowly during normal operation, and some reducers can be used for more than 10 years. If the wear speed is faster, it is necessary to consider whether the selection is correct, whether it is overloaded, and the material, assembly quality or use environment of the worm gear.
3. Drive small helical gear wear. It usually occurs on a vertical mounted reducer, mainly related to the amount of lubricant added and the type of oil. When the vertical installation is installed, it is easy to cause insufficient lubricant. When the reducer stops running, the transmission gear oil between the motor and the reducer is lost, and the gears are not protected by the lubrication. When the reducer is started, the gears are mechanically worn or even damaged due to the lack of effective lubrication.
4. The worm bearing is damaged. In the event of a fault, even if the gearbox is well sealed, it is often found that the gear oil in the reducer is emulsified and the bearing is rusted, corroded and damaged. This is because the condensed water produced by the gear oil temperature rises and cools after mixing for a period of time. Of course, it is also closely related to bearing quality and assembly process.
Second, SEW reducer solution
1. Guarantee the quality of assembly. You can purchase or make some special tools. When disassembling and installing the parts of the reducer, try to avoid hitting with other tools such as hammers. When replacing gears and worm gears, try to use original parts and replace them in pairs. When assembling the output shaft, pay attention to it. Tolerance fit; use a release agent or red dan oil to protect the hollow shaft to prevent wear and rust or to match the area scale, which is difficult to disassemble during maintenance.
2. Selection of SEW reducer. The worm gear reducer generally uses 220# gear oil. For heavy-duty trucks with heavy load, frequent start and poor use environment, some lubricating oil additives can be used to make the gear oil still adhere to the gear surface when the reducer stops running, forming protection. Membrane to prevent heavy load, low speed, high torque and direct contact between metals at start-up. The additive contains a seal regulator and a leak preventer to keep the seal soft and elastic, effectively reducing lubricant leakage.
3. Selection of SEW reducer installation position. When possible, do not use a vertical installation. When installing vertically, the amount of lubricating oil added is much more than that of horizontal installation, which may cause heat generation and oil leakage of the reducer.
Reduction ratio: The ratio of input speed to output speed. Series: Number of sets of planetary gears. Generally, Zui can reach Level 3, and the efficiency will be reduced. Full load efficiency: In the case of large load of zui (fault stop output torque), the transmission efficiency of the reducer. Working life: The cumulative working time of the reducer under rated load and rated input speed. Rated torque: It is the long-running torque allowed for the rated life. When the output speed is 100 rpm, the life of the reducer is the average life. When this value is exceeded, the average life of the reducer will decrease.
The gear unit fails when the output torque exceeds twice. Noise: dB (A) in decibels. This value is the input speed of 3000 rpm, without load, measured at a distance of 1 m from the reducer. Hysteresis: The input end is fixed, the output end rotates clockwise and counterclockwise. When the output end is subjected to positive and negative 2% rated torque, the output end of the reducer is displaced by a slight angular displacement, which is the return gap. The unit is "minute", which is 1/60 of the first degree.