Skill
1. After 200 to 300 hours of operation, the oil should be changed for the first time, and the quality of the oil should be checked regularly in the future use, and the oil mixed with impurities or deteriorated should be replaced in time. Under normal circumstances, for a long-term continuous working reducer, the new oil should be replaced by 5000 hours of operation or once a year, and the long-term deactivated reducer should also be replaced with new oil before restarting. The reducer should be filled with oil of the same grade as the original, and should not be mixed with oils of different grades. Oils of the same grade but with different viscosities are allowed to be mixed;
2. When changing the oil, wait until the reducer has cooled down and there is no danger of burning, but it should still be kept warm, because after the complete cooling, the viscosity of the oil will increase and it will be difficult to drain the oil. Note: Cut off the power supply of the transmission device to prevent accidental power-on;
3. During work, when the oil temperature rises above 80°C or the oil pool temperature exceeds 100°C and abnormal noise is found, stop using it. Check the cause, remove the fault, and replace the lubricating oil before continuing to run. ；
4. The user should have reasonable use and maintenance rules and regulations, and carefully record the operation of the reducer and the problems found during the inspection. The above regulations should be strictly implemented.
maintain
Grease selection When selecting the grease according to the bearing load of the walking reducer, the grease with a small penetration degree should be selected for heavy loads. When working under high pressure, in addition to low penetration, it also has higher oil film strength and extreme pressure performance. Calcium-based grease has good water resistance, is not easy to emulsify and deteriorate through water, and can be suitable for the lubrication of various mechanical parts in humid environments or in contact with water. When selecting grease according to working temperature, the main indicators should be dropping point, oxidation stability and low-temperature performance. The dropping point can generally be used to evaluate high-temperature performance. The actual working temperature of the bearing should be 10-20°C lower than the dropping point. The use temperature of synthetic grease should be 20-30℃ lower than the dropping point.
Different lubricating oils are not allowed to be mixed with each other. The positions of the oil level plug, the oil drain plug and the breather are determined by the installation position.
Oil level check:
1. Cut off the power to prevent electric shock. Wait for the reducer to cool down;
2. Remove the oil level plug and check if the oil is full;
3. Install the oil level plug.
Oil inspection:
1. Cut off the power to prevent electric shock. Wait for the reducer to cool down;
2. Open the oil drain plug and take an oil sample;
3. Check the viscosity index of the oil: if the oil is obviously turbid, it is recommended to replace it as soon as possible;
4. For the reducer with oil level plug: check the oil level to see if it is qualified; install the oil level plug.
Oil replacement:
After cooling, the viscosity of the oil increases and it is difficult to drain the oil. The reducer should change the oil at the operating temperature.
1. Cut off the power to prevent electric shock. Wait for the reducer to cool down and there is no danger of burning;
Note: The reducer should still be warm when changing the oil;
2. Put an oil pan under the oil drain plug;
3. Open the oil level plug, breather and oil drain plug;
4. Remove all the oil;
5. Install the oil drain plug;
6. Inject new oil of the same brand;
7. The amount of oil should be consistent with the installation position;
8. Check the oil level at the oil level plug;
9. Tighten the oil level plug and breather.
Fault handling
Due to the harsh operating environment of the reducer, failures such as wear and leakage often occur. The most important ones are:
1. Wear of the bearing chamber of the reducer , including the wear of the housing bearing box, the inner bore bearing chamber of the box, and the gearbox bearing chamber;
2. The shaft diameter of the gear shaft of the reducer is worn, and the main wear parts are the shaft head, keyway, etc.;
3. The bearing position of the drive shaft of the reducer is worn;
4. Leakage on the joint surface of the reducer.
For the wear problem, the traditional solution is repair welding or machining and repair after brush plating , but both have certain drawbacks: the thermal stress generated by the high temperature of repair welding cannot be completely eliminated, and it is easy to cause material damage and cause the parts to bend or break; and Electric brush plating is limited by the thickness of the coating and is easy to peel off. The above two methods use metal to repair the metal, which cannot change the "hard-to-hard" coordination relationship. Under the combined action of various forces, it will still cause re-wear. For some large bearing companies, it is impossible to solve on-site, and most of them have to rely on outsourcing to repair. Contemporary Western countries mostly use polymer composite repair methods for the above problems , which have super adhesion, excellent compressive strength and other comprehensive properties. The application of polymer materials for repair can avoid disassembly and machining. There is no thermal stress for repair welding, and the repair thickness is not limited. At the same time, the product has a retreat that the metal material does not have, which can absorb the shock and vibration of the equipment and avoid re-wearing. Possibly, and greatly extend the service life of equipment components, save a lot of downtime for enterprises, and create huge economic value.
For the leakage problem, the traditional method needs to disassemble and open the reducer, replace the sealing gasket or apply sealant , which is time-consuming and laborious, and it is difficult to ensure the sealing effect, and leakage will occur again during operation. The polymer material can treat leakage on site. The material has superior adhesion, oil resistance and 350% stretch, overcomes the impact of reducer vibration, and solves the problem of reducer leakage for enterprises.
Reason analysis of oil leakage of reducer
1. Pressure difference between the inside and outside of the reducer: During the operation of the reducer, the friction heat of the movement pair and the influence of the ambient temperature increase the temperature of the reducer. If there is no vent or clogged vent, the pressure inside the machine will gradually increase. The higher the internal temperature, the greater the pressure difference with the outside world, and the lubricating oil will leak from the gap under the action of the pressure difference.
2. The structure design of the reducer is unreasonable
1) The inspection hole cover is too thin, and it is easy to deform after tightening the bolts, making the joint surface uneven and oil leakage from the contact gap;
2) During the manufacturing process of the reducer, the castings are not subjected to annealing or aging treatment, and the internal stress is not eliminated, which will inevitably be deformed, generate gaps, and cause leakage;
3) There is no oil return groove on the box body, and the lubricating oil accumulates in the shaft seal, end cover, joint surface, etc., and leaks from the gap under the action of the pressure difference;
4) The design of the shaft seal structure is unreasonable. Early speed reducers mostly used oil groove and felt ring type shaft seal structure. When assembling, the felt was compressed and deformed, and the joint surface gap was sealed. If the contact between the journal and the seal is not ideal, the seal will fail in a short time due to the extremely poor compensation performance of the felt. Although there is an oil return hole on the oil ditch, it is very easy to be blocked and the oil return effect is difficult to play.
3. Too much lubrication: During the operation of the reducer, the oil pool is greatly agitated, and the lubricating oil splashes everywhere in the machine. If the lubricating amount is too much, a large amount of lubricating oil will accumulate on the shaft seal, joint surface, etc. Cause a leak.
4, improper maintenance process: when the equipment maintenance, since the bonding surface of the soil removal is not complete, or sealant improper selection, hold against the direction of the seal, not promptly replaced seals can also lead to leakage. [4]
Countermeasures to control oil leakage of reducer
1. Improve the vent cap and inspection hole cover: The internal pressure of the reducer is greater than the external atmospheric pressure is one of the main reasons for oil leakage. If you try to balance the pressure inside and outside the machine, oil leakage can be prevented. Although the reducer has a vent cap, the vent hole is too small, it is easy to be blocked by coal powder and oil, and the inspection hole cover must be opened every time the oil is refueled. Once opened, the possibility of oil leakage will increase once, making the original leak-proof Leaks also occurred in places. For this reason, an oil cup type vent cap was made, and the original thin inspection hole cover was changed to 6 mm thick, and the oil cup type vent cap was welded to the cover. The diameter of the vent is 6 mm, which is convenient for ventilation. The pressure is equalized, and the oil is added from the oil cup when refueling, without opening the inspection hole cover, which reduces the chance of oil leakage.
2. Smooth flow: To prevent the excess lubricating oil thrown on the bearing by the gear from accumulating at the shaft seal, the excess lubricating oil must flow back to the oil pool in a certain direction, that is, to achieve a smooth flow. The specific method is to open an oil return groove in the center of the lower shell of the bearing seat that is inclined toward the inside of the machine, and at the same time open a gap at the straight opening of the end cover, the gap is directly opposite to the oil return groove, so that the excess lubricating oil flows through the gap and the oil return groove. Return to the oil sump.
3. Improve the shaft seal structure
1) The shaft seal of the reducer with the output shaft as a half shaft is improved: the output shaft of the reducer in most equipment such as belt conveyors , screw unloaders, and impeller coal feeders is a half shaft, which is more convenient for modification. Disassemble the reducer, remove the coupling, take out the shaft seal end cover of the reducer, machine the groove on the outer side of the original end cover according to the size of the supporting frame oil seal , install the frame oil seal, and the side with the spring is inward. When reinstalling, if the end cover is more than 35 mm away from the inner end surface of the coupling, a spare oil seal can be installed on the shaft outside the end cover. Once the oil seal fails, the damaged oil seal can be removed and the spare oil seal can be pushed into the end cover. Eliminate the time-consuming and laborious processes such as disassembling the reducer and disassembling the coupling.
2) Improved shaft seal of the reducer whose output shaft is the whole shaft: The output shaft of the reducer with the whole shaft transmission has no coupling. If it is modified according to the 2.3.1 scheme, the workload is too large and unrealistic. In order to reduce the workload and simplify the installation procedure, a split-type end cover was designed, and an opening-type oil seal was tried. The outer side of the split end cover is machined with grooves. When installing the oil seal, first remove the spring and saw the oil seal into an opening. Put the oil seal on the shaft from the opening, butt the opening with adhesive, and then install the opening upward. Put on the spring and push in the end cap.
4. Adopting new sealing materials : For the leakage of static sealing points of the reducer, new polymer repair materials can be used to repair the stickiness and blockage. If the static sealing point of the reducer leaks oil during operation, the oil surface emergency repair agent of surface engineering technology can be used to plug it with polymer 25551 and 90T composite repair materials, so as to achieve the purpose of eliminating oil leakage.
5. Carry out the maintenance process carefully: When the reducer is overhauled, the process specifications must be carefully implemented. The oil seal must not be installed reversely, the lip must not be damaged, the outer edge must not be deformed, the spring must not fall off, the joint surface must be cleaned, the sealant must be evenly applied, and the oil must be applied. The amount should not exceed the scale of the oil dipstick.
6. Wiping: The static sealing point of the reducer can generally be leak-proof through treatment. However, due to the aging of the seal, poor quality, improper assembly, high shaft surface roughness and other reasons, the dynamic sealing point still remains There is a small leakage. Due to the poor working environment, coal dust sticks to the shaft and appears to be oily. Therefore, it is necessary to wipe off the oil on the shaft after the equipment is stopped.
Noise treatment
The noise of the reducer is mainly caused by the friction, vibration and collision of the transmission gear. How to effectively reduce and reduce the noise to make it more in line with environmental protection requirements is also a key research topic at home and abroad. Reducing the gear transmission noise during the operation of the reducer has become an important research topic in the industry. Many scholars at home and abroad regard the change of gear tooth meshing stiffness in gear transmission as the main factor of gear dynamic load, vibration and noise. Use the method of shape modification to minimize the dynamic load and speed fluctuation to achieve the purpose of reducing noise. This method has proved to be a more effective method in practice. However, with this method, the process requires shaping equipment, which is often not possible in the majority of small and medium-sized factories.
After years of research, it is proposed to optimize gear parameters, such as modification coefficient , tooth height coefficient, pressure angle, center distance, to minimize the impact velocity of engagement, and the ratio of impact velocity of engagement to a certain value. Range, reduce or avoid the gear design method of the impact of the meshing pitch circle, can also significantly reduce the gear noise of the reducer. For the noise problem of the reducer, you can also use Metre Super Sealant or Lubricant. It is an excellent gearbox additive that can form a thin film of inert material on the components, thereby reducing friction, gear noise and leakage. [4]
installation method
In the reducer family, planetary reducers are used in servo, stepping, DC and other transmission systems because of their small size, wide reduction range, high precision and many other advantages. Its function is to reduce the speed, increase the torque and reduce the load/motor moment of inertia ratio while ensuring precise transmission. In the past few years, some users have broken the output shaft of the reducer due to illegal installation and other human factors when using the reducer, causing the company to suffer unnecessary losses. Therefore, in order to better help the majority of users to use the reducer, I will introduce you in detail how to install the planetary reducer correctly.
Correct installation and use of reducers are important links to ensure the normal operation of mechanical equipment. Therefore, when installing the planetary reducer, please strictly follow the installation and use related matters below, and carefully assemble and use it.
first step
Before installation, confirm whether the motor and reducer are intact, and strictly check whether the dimensions of the parts connecting the motor and the reducer are matched. Here are the dimensions and tolerances of the positioning boss of the motor, the input shaft and the groove of the reducer.
Second step
Unscrew the screw on the dust-proof hole on the outer side of the reducer flange, adjust the PCS system clamping ring to align the side hole with the dust-proof hole, and insert the inner hexagon to tighten. After that, remove the motor shaft key.
third step
Connect the motor and the reducer naturally. When connecting, it must be ensured that the concentricity of the output shaft of the reducer and the input shaft of the motor is the same, and the outer flanges of the two are parallel. If the center is inconsistent, it will cause the motor shaft to break or the gear of the reducer to wear. In addition, during installation, it is strictly forbidden to hit with a hammer, etc., to prevent excessive axial or radial force from damaging the bearings or gears. Be sure to tighten the mounting bolts before tightening the tightening bolts. Before installation, wipe off the anti-rust oil on the motor input shaft, positioning boss and the connection part of the reducer with gasoline or zinc-sodium water. Its purpose is to ensure the tightness of the connection and the flexibility of operation, and to prevent unnecessary wear.
Before connecting the motor to the reducer, the keyway of the motor shaft should be perpendicular to the tightening bolt. To ensure uniform force, first screw on the mounting bolts at any diagonal position, but do not tighten, then screw on the other two diagonal mounting bolts, and finally tighten the four mounting bolts one by one. Finally, tighten the tightening bolts. All tightening bolts need to be fixed and inspected with a torque wrench according to the marked fixed torque data. The correct installation between the reducer and mechanical equipment is similar to the correct installation between the reducer and the drive motor. The key is to ensure that the output shaft of the reducer is consistent with the concentricity of the driven part of the shaft.
1. The connection between the reducer and the working machine: The reducer is directly set on the main shaft of the working machine. When the reducer is running, the reaction torque acting on the reducer case body is installed on the reducer case body or other Method to balance. The machine is directly matched, and the other end is connected with the fixed bracket;
2. Installation of the counter-moment bracket: The counter-moment bracket should be installed on the side of the working machine facing the reducer to reduce the bending moment attached to the working machine shaft. The shaft sleeve of the counter-moment support and the fixed support joint end uses rubber and other elastic bodies to prevent flexure and absorb the generated torque fluctuations;
3. The installation relationship between the reducer and the working machine: in order to avoid the deflection of the main shaft of the working machine and the additional force on the bearing of the reducer, the distance between the reducer and the working machine should be as small as possible without affecting normal working conditions. , Its value is 5-10mm.
The correct installation, use and maintenance of the reducer is an important part of ensuring the normal operation of mechanical equipment.
1. When installing the reducer, attention should be paid to the centering of the transmission center axis, and the error should not be greater than the compensation amount of the coupling used. Good alignment can prolong service life and obtain ideal transmission efficiency;
2. When installing the transmission part on the output shaft, it is not allowed to hit with a hammer. Usually the assembly fixture and the internal thread of the shaft end are used to press the transmission part in with bolts, otherwise it may cause damage to the internal parts of the reducer. It is best not to use a rigid fixed coupling, because improper installation of this type of coupling will cause unnecessary external loads, which will cause early damage to the bearing, and even cause the output shaft to break in severe cases;
3. The reducer should be firmly installed on a stable level foundation or base, the oil in the oil drain groove should be drained, and the cooling air circulation should be smooth. The foundation is unreliable, which will cause vibration and noise during operation, and cause damage to bearings and gears. When the transmission coupling has protrusions or adopts gears or sprockets for transmission, it should be considered to install protective devices. When the output shaft bears a large radial load, the reinforced type should be selected;
4. Install the device according to the regulations to ensure that the staff can easily approach the oil mark, vent plug and oil drain plug. After the installation is in place, the accuracy of the installation position should be comprehensively checked in order, the reliability of the pressing of the fasteners, and it should be able to rotate flexibly after installation. The reducer adopts oil pool splash lubrication. Before operation, the user needs to remove the screw plug of the vent hole and replace it with the vent plug. Check the height of the oil level line by opening the oil level plug screw according to different installation positions. Add oil from the oil level plug until the lubricating oil overflows from the oil level plug screw hole. Load trial run, the time shall not be less than 2 hours. The operation should be stable, and there should be no shock, vibration, noise and oil leakage. Any abnormality should be eliminated in time.
After a certain period of time, the oil level should be checked again to prevent possible leakage from the casing. If the ambient temperature is too high or too low, the grade of the lubricant can be changed.
Model selection
Try to choose a reduction ratio close to the ideal: reduction ratio = servo motor speed / reducer output shaft speed. Torque calculation: For the life of the reducer, the torque calculation is very important, and pay attention to the maximum torque value (TP) of the acceleration, whether it exceeds the maximum load torque of the reducer.
The applicable power is usually the applicable power of the servo models on the market. The applicability of the reducer is very high, and the working coefficient can be maintained above 1.2, but the selection can also be determined according to your own needs. There are two main points:
1. The output shaft diameter of the selected servo motor cannot be greater than the maximum use shaft diameter on the table;
2. If the torque is calculated, the speed can meet the normal operation, but when the servo is in full output, if there is insufficient phenomenon, you can use the driver on the motor side to limit current control, or to do torque protection on the mechanical shaft. This is Very necessary.
The selection of general reducer includes steps such as proposing original conditions, selecting types, and determining specifications. In contrast, the type selection is relatively simple, and the working conditions of the reducer are accurately provided, and the design, manufacture and use characteristics of the reducer are the key to the correct and reasonable selection of the specifications of the general reducer. The selection of specifications should meet the conditions of strength, thermal balance, and radial load bearing on the shaft extension.
Select specifications:
The biggest difference between the general reducer and the special reducer design and selection method is that the former is applicable to various industries, but the reduction can only be designed according to a specific working condition, so users need to consider different correction factors according to their requirements when selecting , The factory should be based on the actual selected motor power (not the rated power of the reducer); the latter is designed according to the user’s special conditions, the factor of consideration is generally taken into account in the design, as long as the use of power is less than or equal to the reducer’s The rated power is sufficient, and the method is relatively simple.
The rated power of the universal reducer is generally based on the use (working condition) coefficient KA=1 (motor or steam turbine is the prime mover, the working machine has a stable load, working 3~10h every day, the number of starts per hour is ≤5 times, and the allowable starting torque is 2 times the working torque), the contact strength safety factor SH≈1, the failure probability of a single pair of gears≈1%, and other conditions are calculated and determined.
The rated power of the selected reducer should meet
PC=P2×KA×KS×KR≤PN
In the formula, PC—calculated power (KW);
PN—the rated power of the reducer (KW);
P2—Working machine power (KW);
KA—use factor, considering the influence of operating conditions;
KS—starting coefficient, considering the influence of the number of starts;
KR—reliability coefficient, considering different reliability requirements.
The usage coefficients used by countries all over the world are basically the same. Although many samples do not reflect the two coefficients of KS and KR, due to knowing oneself (clear requirements for their own working conditions) and knowing the enemy (clear performance characteristics of the reducer), foreign countries generally have larger ones when selecting models. The amount of surplus is equivalent to considering the influence of KR\KS.
Due to different use occasions, different importance levels, different sizes of losses to personal safety and production after damage, and different maintenance difficulties, the requirements for the reliability of the reducer are also different. The coefficient KR is the actual reliability needed to modify the reliability of the original design. It complies with ISO6336, GB3480 and AGMA2001-B88 (American Gear Manufacturers Association Standard) on the gear strength calculation method. Some domestic users cannot provide specific requirements for the reliability of the reducer. According to the design regulations of general special reducers (SH≥1.25, failure probability≤1/1000), take KR=1.25=1.56 for more important occasions. .
Thermal balance check:
The allowable thermal power value of the universal reducer is based on the maximum allowable equilibrium temperature of the lubricating oil (generally 85 ℃) OK.
When the conditions are different, it is corrected according to the corresponding coefficient (sometimes integrated into a coefficient).
The selected reducer should meet
PCt=P2×KT×KW×KP≤Pt
Where PCt—calculated thermal power (KW);
KT—Environmental temperature coefficient;
KW—operating cycle coefficient;
KP—power utilization factor;
Pt—Allowable thermal power of reducer (KW).
Check the load of the shaft:
General-purpose reducers often have to limit the maximum radial load allowed by the middle part of the input shaft and output shaft extension, which should be checked. When exceeding, the manufacturer should ask the manufacturer to increase the shaft diameter and increase the bearing.
Lubrication maintenance
Before putting it into operation, put the recommended model and value of grease into the reducer . The reducer is lubricated with lubricating oil. For the vertically installed reducer, since the lubricating oil may not guarantee the reliable lubrication of the uppermost bearing, additional lubrication measures are adopted.
Before running, inject an appropriate amount of lubricating oil into the reducer. The reducer is usually equipped with an oil filling hole and an oil drain plug. Therefore, the installation location must be specified when ordering the reducer.
The working oil temperature cannot exceed 80°C.
The life-time lubricated combination reducer is filled with synthetic oil in the manufacturer. In addition, the reducer is usually supplied without lubricating oil, and comes with an oil filling plug and an oil drain plug. The quantity of lubricating oil for the reducer listed in this catalog is only an estimate. Set the position of the oil level plug according to the installation position specified when ordering to ensure correct oil filling. The oil filling amount of the reducer should be determined according to different installation methods. If the transmission power exceeds the heat capacity of the reducer, an external cooling device must be provided.
Account not verified