Explanation of worm gear reducer with deep analysis

Among many reducer types, worm gear reducer is a common reducer. Worm gear reducer is a power transmission mechanism, which uses the speed converter of gear to reduce the rotation number of motor (motor) to the required rotation number and obtain a large torque. It is mainly composed of transmission parts, worm gear, shaft, bearing, box and its accessories. It can be seen in the transmission system of all kinds of machinery, from ships, cars and locomotives of vehicles, heavy machines and tools for construction, processing machines and tools and automatic production equipment used in the mechanical industry, to common household appliances, clocks and watches in daily life. Its applications range from large power transmission work to small load, Accurate angle transmission can see the application of reducer, and in industrial application, reducer has the function of reducing speed and increasing torque. Therefore, it is widely used in speed and torque conversion equipment.

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The basic structure of worm gear reducer is mainly composed of transmission parts, worm gear, shaft, bearing, box and its accessories. It can be divided into three basic structural parts: box, worm gear and worm, bearing and shaft combination. The box is the base of all accessories in the worm gear reducer. It is an important accessory to support and fix the shafting components, ensure the correct relative position of the transmission accessories and support the load acting on the reducer. The worm gear is mainly used to transmit the motion and power between the two staggered shafts, and the bearing and shaft are mainly used to transmit power, operate and improve efficiency.

Knowledge of worm gear reducer

efficiency

Due to the high loss of sliding friction of worm gear reducer, compared with helical gear, bevel gear hard tooth surface reducer has higher loss and low efficiency, which is mainly determined by the following factors:

Transmission ratio of helical gear worm stage

Input speed

Gearbox temperature the efficiency of the worm gear reducer designed by Risco is significantly higher than that of the single-stage worm gear reducer, and its efficiency is possible only for the worm gear reducer with large speed ratio η＜ 0.5。

Self locking condition

Adding reverse torque to helical gear worm gear will produce a reverse efficiency η’= 2-1/ η， Its value is obviously less than the positive efficiency η， If positive efficiency η ≤ 0.5, then the worm gear reduction opportunity is self-locking. Only a few worm gear reducers with large speed ratio have static self-locking. If you want to use the self-locking braking effect, please consult our company

Initial stage of operation

Because the tooth surface of the new worm gear reducer is not smooth enough and the friction angle is large, the efficiency is smaller than that in normal operation. This effect becomes more obvious when the transmission ratio is large.

Agitation loss

In some installation positions, the first stage pinion is completely immersed in oil. For reducer with large seat number and reducer with high input speed, the stirring loss will rise sharply and can not be ignored. Therefore, in case of such situations, please consult Demai transmission of our company.

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Characteristics of worm gear reducer

1. The structure of worm gear reducer is very compact, its volume is also very light, and its shape is relatively ingenious. It has the characteristics of small but efficient, good heat dissipation and good heat exchange.

2. The installation of worm gear reducer is also relatively simple. It has flexible characteristics, and the worm reducer also has the advantage of easy maintenance. Its advantages also include stable transmission, low noise and durability. It is a good product we choose.

3. Worm gear reducer also has the characteristic of large output torque. It also has high safety and reliability, which is of great benefit to our use.

Common problems and Solutions

Common faults of worm gear reducer

1. Heat and oil leakage of reducer. In order to improve efficiency, worm gear reducers generally use non-ferrous metals as worm gears, and the worm adopts harder steel. Due to the sliding friction transmission, more heat will be generated during operation, resulting in differences in thermal expansion between various parts and seals of the reducer, resulting in gaps on various mating surfaces. The lubricating oil becomes thinner due to the increase of temperature, which is easy to cause leakage.

There are four main reasons for this situation: first, the collocation of materials is unreasonable; Second, the surface quality of the meshing friction surface is poor; Third, the selection of lubricating oil addition amount is incorrect; Fourth, the assembly quality and use environment are poor.

2. Worm gear is worn. The worm gear is generally made of tin bronze. The matched worm material is hardened to hrc4555 with 45 steel or hrc5055 with 40Cr, and then ground to roughness Ra0.8 by worm grinder μ m。 The reducer wears very slowly during normal operation, and some reducers can be used for more than 10 years. If the wear speed is fast, it is necessary to consider whether the type selection is correct, whether it operates under overload, as well as the material, assembly quality or service environment of the worm gear.

3. The transmission pinion is worn. It usually occurs on the reducer installed vertically, which is mainly related to the addition amount and variety of lubricating oil. During vertical installation, it is easy to cause insufficient lubricating oil. When the worm gear reducer stops running, the transmission gear oil between the motor and the reducer is lost, and the gear can not get due lubrication protection. When the reducer is started, the gears are not effectively lubricated, resulting in mechanical wear or even damage.

4. The worm bearing is damaged. In case of failure, 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 after the reducer operates for a period of time, the condensate produced after the gear oil temperature rises and cools down is mixed with water. Of course, it is also closely related to bearing quality and assembly process.

Troubleshooting

1. Ensure assembly quality. Some special tools can be purchased or self-made. When disassembling and installing reducer components, try to avoid knocking with hammers and other tools; When replacing gears, worm gears and worms, try to select original accessories and replace them in pairs; When assembling the output shaft, pay attention to tolerance fit; Use anti sticking agent or red lead oil to protect the hollow shaft from wear, rust or scale on the mating area, which is difficult to disassemble during maintenance.

2. Selection of lubricating oil and additives. Worm gear reducers generally use 220# gear oil. For worm gear reducers with heavy load, frequent startup and poor service environment, some lubricating oil additives can be selected to make the gear oil still adhere to the gear surface when the reducer stops running and form a protective film to prevent heavy load, low speed, high torque and direct contact between metals during startup. The additive contains sealing ring regulator and anti leakage agent to keep the sealing ring soft and elastic and effectively reduce lubricating oil leakage.

3. Selection of installation position of worm gear reducer. If the location permits, vertical installation shall not be adopted as far as possible. In vertical installation, the amount of lubricating oil added is much more than that in horizontal installation, which is easy to cause heating and oil leakage of the reducer.

4. Establish a good lubrication maintenance system. The reducer can be maintained according to the "five determinations" principle of lubrication work, so that each reducer is regularly inspected by the responsible person. If the temperature rise is obvious, exceeding 40 ℃ or the oil temperature exceeds 80 ℃, the quality of the oil decreases, or more copper powder and abnormal noise are found in the oil, it shall be stopped immediately, repaired in time, eliminated and replaced. When refueling, pay attention to the oil quantity to ensure that the worm gear reducer is properly lubricated.