Scraper conveyor and belt conveyor are commonly used transportation machinery in coal mines. The correctness and repair of the reducer is related to the production and safety of coal mines. According to the frequent failures of the reducer, combined with years of work practice, an analysis of how to repair and install.
When assembling the bearings, the environment and parts must be kept clean. The bearings are cleaned with kerosene or gasoline, and the end faces marked with the words face outward. When mounting the bearing, first measure the diameter of the shaft and the hole with a vernier caliper or a micrometer. Unqualified parts outside the tolerance range shall not be used. There are three types of bearing assembly methods: hammering method, press assembly method and heating method.
Hammering is a relatively simple method and is generally used in the assembly of smaller diameter bearings with less interference. When installing the bearing with a hammering method, it should be padded with soft metal, such as a copper rod. Do not hit only one side or one side when hitting it. When the bearing is mounted on the shaft, the force is added to the inner race, and the force is applied to the outer race when installed in the bore. When the bearing is installed, the hammer is not directly hit on the entire bearing, so that the inner ring, the outer ring and the bearing frame are all stressed, so that the bearing is most easily damaged and the quality is lowered. Press assembly is generally used in the assembly of rolling bearings with large diameters and small interferences. The bearings must be pressed into the shaft or hole using a soft metal sleeve.
The heating method is a relatively common method used in the assembly of bearings with large diameters and large interference. When hot-loading, the bearing should be heated in the oil, and the heating temperature is determined according to the interference size, but the heating temperature generally does not exceed 100 °C.
The bearing should be heated slowly in the oil. It should not be placed directly into the bearing in the high temperature oil. The temperature of the oil should be measured at any time with a thermometer. A grid shall be provided in the oil basin used for heating, and the bearing shall be placed on the grid, and the oil shall all be immersed in the bearing. Do not place the bearing directly in contact with the pelvis to prevent dirt from entering the bearing and local overheating of the bearing. The appropriate oil basin and grid should be selected according to the size of the bearing. The location of the heating should be a location where the air is fresh and safe. When heating, pay attention to safety, prevent fire and oil pan dumping and other burned personnel, fire extinguishers, sand, water, iron shovel and other fire-fighting equipment should be prepared. It is forbidden to place the bearing on the electric furnace or directly heat it with fire, which will burn the bearing and cause annealing, resulting in deterioration of quality.
The appropriate assembly method should be selected according to the tolerance of the hole and the shaft. When the bearing in the reducer is mounted on the shaft, the base hole and interference fit should be used. When installed in the hole of the reducer, the base shaft system and clearance fit should be adopted. When the shaft diameter and diameter of the reducer exceed the tolerance requirements and the bearing wear exceeds its limit, it must be replaced and must not be used. Adjustment of bearing clearance. The bearing clearance is divided into two types: radial clearance and axial clearance. The two are closely related. If the clearance is too large or too small, it will cause poor operation and even accidents. The adjustment of the axial clearance generally uses the adjustment pad or the adjusting nut to adjust the size of the gap. The correct installation of the gears The repair and assembly quality of the gears is directly related to the service life of the gearbox. The inter-tooth engagement clearance and contact area are important indicators for checking the quality of the gear installation.
When inspecting gears, if there are uneven tooth surface wear, abnormal marks or partial peeling, check the gear center distance, parallelism of each axis, gear clearance, lubrication and lubricating oil. Reasonable assembly of coal mine conveyor reducer Jia Yongjun Coal Technology Jia Yongjun: Reasonable assembly condition of coal mine underground conveyor reducer. During the inspection, a tooth surface peeling was found, but the area did not exceed 30 of the effective meshing area of ​​the gear, and other parts could continue to be used normally. When the tooth surface peeling increases, the operation gradually deteriorates and should be replaced immediately. Practice has shown that even uniform and less severe ablation occurs along the tooth width (especially above and below the index circle), as long as the lubrication and timely maintenance inspections are strengthened, it can be used for a while.
Checking the gear clearance and adjusting the gear clearance are divided into top clearance and backlash. The gears in the reducer are generally spur gears, helical gears and arc bevel gears. The correct condition for gear meshing is equal modulus and equal pressure angle. When the gear meshes with the transmission, a certain tooth top and flank clearance must be maintained between the teeth, which is mainly to store the necessary lubricating oil, thereby reducing the wear between the teeth. If the clearance is too large or too small, the gear will be damaged and an accident will result. The magnitude of the gap is related to the gear modulus and accuracy. The larger the modulus, the lower the accuracy, the larger the gap, and the smaller the opposite.
When measuring by the lead wire method, the soft lead wire of suitable diameter is bent in a substantially tooth shape and placed on the gear, and then the gear is meshed and rolled. The thickness of the soft lead wire after crushing is equivalent to the value of the tooth tip and the flank clearance. , the value can be measured with a vernier caliper.
Gear meshing contact area requirements Gear meshing transmission, the contact area has certain requirements, the correct contact area is directly related to the life of the gear and reducer. The gear clearance can be checked with a feeler gauge or a lead wire method. The tip and flank clearance of the gear can be directly measured with a feeler gauge.
The contact area can be checked by coloring. During the inspection, the color is applied to the pinion gear, the large gear is driven by the pinion gear, and after the large gear is rotated 35 revolutions, the painted spots are displayed on the tooth surface of the large gear. According to the color trace, the correctness of the gear assembly can be judged. The size of the contact area is related to the accuracy level of the gear. The higher the accuracy, the larger the contact area should be. The bevel gear has a larger contact area than the spur gear, and the contact area is larger at the time of heavy load than at no load.
The arc bevel gear meshes with the correct contact area in the middle of the tooth, and the tooth length and tooth height are not less than 50. To avoid contact at the small end of the gear, the contact area is larger when the load is heavy. The two conical apexes of the bevel gear and O must coincide. The contact area of ​​the teeth can be adjusted by changing the axial displacement of one and two axes. The two-axis arc bevel gear must be fastened and not loosened when it is connected to the shaft. Otherwise, the phenomenon of stringing will occur, causing the two arc bevel gears to not mesh properly.
There are certain requirements on the material and hardness of the gear. Unreasonable materials and hardness can also cause damage to the teeth, such as fatigue pitting, plastic deformation, breakage and accelerated wear. The cooler in the reducer is used to cool the oil. If the oil temperature is too high, the bearings and gears will be damaged. Therefore, the cooler must be used and cannot be removed.
If it is not replaced in time, the hole will become bigger and bigger, resulting in a bigger accident. When installing underground, the water inlet and outlet must be connected, and water should be used to cool the oil temperature in the reducer.
The center line of the motor, coupling, reducer, sprocket assembly (or active roller) must be horizontal, and the clearance, radial deviation and tilt deviation of each part meet the requirements. All bolts must be aligned, topped and fastened. It is necessary to strengthen the inspection and maintenance, and regularly change the lubricating oil and the amount of oil is appropriate. Keep the oil clean when refueling to prevent dirt from entering the oil. The oil level exceeds 1/3 of the diameter of the gear reducer. Add the appropriate amount of oil and oil according to the gear unit. Too much or too little oil will shorten the life of the reducer and even lead to even more accidents.
The power supply system is not perfect. (1) There is no special electric pressure pump and breaker drive switch. Once the heating plate control box fails, the pressurized pump power supply must be removed. The pressure water cannot be guaranteed, and the temperature of the heating plate is lower than the regulation for a long time. Temperature affects the quality of vulcanization and the progress of vulcanization
(2) The vulcanized heating plate control box is not a special starter for the pressure pump and the broken belt machine. Once the failure occurs, it will have a major impact on the quality of the vulcanization. In severe cases, the joint will be scrapped.
(3) The bare non-explosion-proof transformer is used to provide the rated voltage of 220V for the grinding machine. Although the air switch provides leakage protection, there are still serious safety hazards.
(4) When the vulcanizer is heated for the first time, the moisture of the vulcanization heating plate rises, and the insulation resistance value decreases, which may cause the leak detection device to operate. If the power is cut off for a long time or the power is not supplied, the vulcanized joint may be scrapped.
Economic High Speed Edm Small Hole Drilling Machine
Economic High Speed Edm Small Hole Drilling Machine,Economic Edm Small Hole Drilling Machine,High Speed Edm Small Hole Drilling Machine,Economic High Speed Small Hole Drilling Machine
Taizhou Jiangzhou CNC Machine Tool Manufacturing Co.,Ltd , https://www.machinetzjz.com