Worm gear reducer is a common mechanical transmission mechanism, which is widely used in mechanical transmission systems of various industries. This paper shares the common faults and maintenance precautions of worm reducer.

1 the role of worm gear reducer The application of worm gear reducer in traditional mechanical system mainly has the following functions: First of all, the output torque of the rotary reducer can be improved after deceleration, and the output of torque is proportional to the output deceleration of motor or hydraulic motor. It should be noted that the torque output cannot exceed the rated torque of the reducer. Secondly, the inertia of the load can be effectively reduced while decelerating, and the inertia reduction is the square of the deceleration ratio. Finally, the speed reducer can change the output direction of torque, so that the output torque and the input torque are vertically distributed.

2 common faults and solutions of worm gear reducer

2.1 reducer heating and oil leakage fault Most worm gears of rotary reducers use steel with hardened tooth surface or high hardness as raw materials, so as to improve the running efficiency and wear resistance of reducers. However, because the transmission mode of rotary reducers is friction transmission, a lot of heat will be generated in the running process, and the temperature will increase rapidly. Over time, the heat will generate a certain amount of heat expansion between various parts and seals of reducers, which will lead to gaps on the surfaces of reducer parts. In addition, the grease temperature will increase and decrease densely. After long-term use, oil leakage and serious tooth surface wear of reducers will easily occur. Therefore, by analyzing the accident, we conclude that the main causes of the accident are as follows: First, the application and collocation of reducer materials are unreasonable. Second, the process quality of meshing tooth surface is unqualified. Third, the selected grease is unreasonable. Fourthly, the factors of equipment assembly quality and operating environment. Therefore, the processing and material selection of parts should be strictly controlled; In the process of assembling or replacing parts of rotary reducer, it is necessary to avoid violent knocking with tools such as hammer, and choose original bearings, oil seals and other accessories for replacement; The worm should be protected with proper grease to avoid wear or rust on the tooth surface.

 2.2 wear of worm gear The machining material of worm gear is S48C, and the matching worm material is 42CrMo steel hardened to HRC45-55, or 40Cr hardened to HRC50-55, and then grinded by worm grinder to make its roughness reach Ra0.8 during the operation of rotary reducer, the worm will polish the worm gear like a "file", which is generally slow and normal If it is found that the worm gear wears abnormally and quickly, we can consider whether the selection of the rotary reducer is wrong, or whether it is overloaded for a long time, and there are factors such as heavy load, high speed and bad running environment. Under normal circumstances, the corresponding lubrication method should be selected according to the actual working conditions of the reducer. If the reducer is in a complex and harsh operating environment, some grease additives should be added appropriately to protect the normal operation and service life of the gear.

2.3 worm bearing damage When the mechanical failure occurs in the reducer, although there is no problem in the sealing of the reducer, the gear grease in the reducer is emulsifying phenomenon, and the bearing is rusted and damaged. The main reason is that the temperature of gear grease is caused by the condensation of moisture after the heat turns cold during the normal operation and shutdown of the reducer. In addition, it also has a certain relationship with the quality and assembly process of the bearing itself. Therefore, in order to prevent the above faults, enterprises should establish a sound lubrication and maintenance system to effectively guarantee the normal operation of the reducer.

2.4 helical gears are worn Generally, the wear of transmission helical gear occurs on the reducer installed horizontally, and the reason of wear is mainly related to the selection and addition of grease. In the process of installation, it is easy to cause the phenomenon of insufficient lubrication. In addition, when the reducer works for a long time, grease is lost from the transmission gear under the action of extrusion, and the gear loses the lubrication protection function of grease. When it is restarted, it will increase friction and cause mechanical wear or damage. Therefore, when installing the horizontal reducer, adequate grease should be added.

3 Maintenance of worm gear reducer

 3.1 Do a good job in daily maintenance. Keep the equipment and surrounding areas clean, free of water and grease; Pay attention to whether abnormal noise occurs during the operation of the reducer at any time; Check whether there is any abnormal jitter and whether the temperature meets the requirements; Pay attention to observe whether there is oil leakage on the upper and lower joint surfaces and the shaft end of the reducer, and eliminate it in time if there is any leakage; Check that the oil level should be in the specified position through oil dipstick or oil level mirror.

3.2 Make periodic maintenance plan. According to the operation of the equipment, a reasonable periodic maintenance plan is set, generally, minor repairs are carried out once every 3-5 months, and major repairs are carried out once every 6-12 months. Minor repairs: tighten loose bolts; Check and replace the wearing parts on the coupling; Eliminate oil leakage or grease loss, and adjust the tooth surface clearance of transmission shaft; Repair the safety protection device. Medium repair: inspect, repair or replace worn driving gear or worm; Check and replace rolling bearings and repair oil baffle; Clean the shell, replace or add grease; Measure tooth surface meshing clearance, repair gear tooth surface and shaft. Overhaul: inspect, repair or replace the driven gear or shaft; Repair the worn bearing seat; Repair and scrape the joint surface of the upper and lower shells or replace the shells.