Service

The possible faults during the use of the reducer include: oil leakage, overheating of the bearing parts, loud noise, excessive temperature of the reducer oil pool (higher than 70 degrees), abnormal noise of the reducer, drive shaft channeling, bearing fragmentation, gear damage Etc., the causes and preventive measures are now analyzed.

1 Oil leakage of reducer

1.1. Reason analysis:

There are many ways of oil leakage, but the most common one is the oil leakage at the seals of the active and driven shaft heads, especially the oil leakage at the sealing ring of the active shaft. In addition to the above-mentioned situations, there are the following 3 oil leakage parts.

a. Oil leakage along the closing surface of the reducer;

b. Oil leakage along the sight hole cover above the reducer;

c. Oil leakage along the oil drain hole at the bottom of the reducer;

The oil leakage at the sight hole cover and the oil drain hole is mainly caused by the fixing bolts are not fully tightened or the sealing gasket is not installed.

When the individual reducer is assembled and closed, there are iron filings on the closing surface, so that the closing surface is not strict and oil leakage occurs. In addition to the above factors, the reason for the oil leakage on the closing surface is that after the reducer is used for a period of time, the casing is deformed, resulting in an uneven closing surface and a loose fit, resulting in oil leakage.

1.2. Prevention and elimination methods

a. The sealing ring gland adopts an easy-to-remove structure.

b. The sealing ring adopts an open structure.

c. The oil return hole at the input shaft bearing should be appropriately enlarged.

d. Aging treatment of the reducer casing can prevent the casing from deforming and avoid oil leakage along the closing surface. At present, there are three aging methods, one is natural failure; the other is artificial aging; the third is vibration aging. It can be selected and processed according to actual conditions.

e. An annular oil groove is cast or machined on the closing surface of the reducer base, and there are multiple oil return holes connected to the annular oil groove. When the reducer is working, once oil seeps into the closing surface, it will enter the annular oil groove, and then flow into the oil tank through the oil return hole, and the lubricating oil will not leak to the outside of the reducer housing along the closing surface.

f. When assembling the reducer, apply a layer of sealant (such as D05 silicone rubber sealant) on the closing surface, which can effectively prevent oil leakage at the closing surface.

g. The oil level of the reducer is too high, which not only increases the power loss of the gear stirring oil, and the splash of lubricating oil seriously increases the chance of oil leakage, but also causes the oil temperature to rise continuously. Especially in summer, the high ambient temperature will increase the oil temperature and lubricate the The oil viscosity decreases, reduces the lubricating performance, increases the fluidity and leakage of the oil, directly affects the lubrication of gears and bearings, and reduces the service life. For this reason, the normal oil level must be maintained during use.

h. Install gaskets at the sight hole cover and the oil drain hole, and tighten the bolts.

l. Enlarge the oil return hole of the output shaft to prevent oil leakage of the output shaft.

j Improved vent cap and inspection hole cover. One of the main reasons for oil leakage is that the internal pressure of the reducer is greater than the external atmospheric pressure. 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, which is easily blocked by dust and oil, and the inspection hole cover must be opened every time you refuel. Opening it once will increase the possibility of an oil leak, so that the original place does not leak. Leaks also occur. The ventilation holes can be enlarged to equalize the pressure inside and outside.

2. The bearing part of the reducer is overheated or the bearing part is noisy

2.1. Reason analysis:

a. Insufficient lubricating oil. When the lubricating oil level is insufficient or cannot reach a reasonable height due to oil leakage of the reducer, it may cause high temperature or noise in the bearing part of the reducer;

b. Bearing cover or sealing part friction. When the bearing is installed incorrectly, the bearing cover is not correct, or the bearing cover or the sealing part and the connecting part are worn out due to long-term use, it may cause the bearing of the reducer to have high temperature or noise;

c. The bearing is damaged or worn. The main content of this item is damage to the cage of the bearing, wear or deformation of the inner and outer rings, wear or drop of the balls, and these reasons will make the reducer unable to work normally;

d. The bearing clearance is too large or too small. The above symptoms may occur when the gap between the balls of the reducer bearing and the inner and outer rings, the gap between the inner ring and the shaft of the bearing, and the gap between the bearing and the end cover become larger due to long-term use;

e. The key handle of the helical gear is loose. Looseness of the key handle of the helical gear will cause the lack of tight fit between the gear and the shaft, resulting in overheating of the bearing or noise;

2.2. Prevention and elimination methods:

a. Check the oil level and add lubricating oil; b. Tighten the bolts of the bearing and connecting parts, and check the installation of the seals; c. Check the bearing, and replace it immediately if it is damaged; d. If the clearance is not suitable, adjust the bearing clearance, which cannot be The bearing should be replaced during adjustment; e. For the loose key handle of the helical gear, it should be repaired in time;

3 The temperature of the reducer oil is too high

3.1. Reason analysis:

a. The lubricating oil is unqualified or used for too long. At present, most of the lubricating oil used in the reducer of our group is 320# extreme pressure gear oil. If you add expired or inconsistent oil with this type of lubricating oil and do not replace the lubricating oil for a long time, it may cause the oil temperature of the reducer to be too high;

b. Too much lubricating oil. When the height of the oil level is higher than the oil dipstick or the upper and lower limit positions of the visible hole, it will cause the oil temperature of the reducer to be too high;

c. The parts are damaged. The damage to the parts includes serious gear pitting, broken teeth, damage to the bearing cage, inner and outer rings, balls, and bearing locking or serious shaft deformation;

d. The outside of the box is covered by debris or dust. When things are stacked around the reducer or the surface of the body has not been cleaned for a long time, it may be covered by debris or dust, which may cause the heat dissipation of the reducer to be incomplete and cause the oil temperature to rise;

e. Blockage or failure of the cooling device. The cooling device is placed in a dusty workshop like the reducer. If the cooling device is blocked or the cooling device is broken due to long-term work without cleaning the internal pipeline, it will cause the oil temperature of the reducer to rise;

3.2. Exclusion method:

a. Replace the lubricating oil; b. Remove the excess oil; c. Carefully check to find the damaged position of the parts and repair or replace the parts in time; d. Remove sundries and dust; e. Replace the cooling device or remove the blockage;

4 The vibration of the reducer is large

4.1. Reason analysis:

a. The anchor screws are loose. Due to the long-term work of the reducer, the anchor screws may be loosened or the screws may be damaged, which will cause the reducer to vibrate greatly and work abnormally;

b. The coupler is damaged. When the coupler connected to the reducer is damaged due to oil leakage, loose screws, etc., its vibration will be transmitted to the reducer, so that the vibration of the reducer is abnormal;

c. The motor screw is loose. Similar to the coupler failure, when the motor vibrates due to various reasons, the vibration will be transmitted to the reducer, making the reducer vibration larger;

d. The bearing is seriously worn. This reason has been explained in 4.2.1, the above reasons will cause the reducer to not work normally;

e. Gear damage. Gear damage includes serious pitting on the tooth surface, large gear meshing clearance, serious gear tooth wear, and broken teeth. These gear wear conditions may be that the reducer cannot work normally due to large vibration;

f. Shaft deformation out of balance. When the strength and hardness of the shaft are lower than the requirements or aging due to long-term work, the shaft will be deformed, and the deformation of the shaft will cause the reducer to vibrate greatly;

4.2. Prevention and elimination methods: a. Tighten the foot bolts; b. Check the damaged parts and causes of the coupler, and repair the coupler in time; c. Tighten the loose screws of the motor; d. Replace the bearing; e. Replace the gear; f. Replace the shaft;

5 Bearing breakage

5.1. Reason analysis: The cracking of the reducer bearing mainly occurs in the drive shaft bearing. The main reason is that when the drive shaft moves, there will be axial sliding between the inner ring of the bearing and the rollers, causing the inner ring of the bearing to move axially, causing the shaft to move. The inner bearing roller is damaged first;

5.2. Prevention and elimination methods: increase the interference between the inner ring and the shaft, or add a retaining ring on the outer side of the inner ring of the bearing to prevent axial movement;

6 The reducer has abnormal noise

6.1. Reason analysis: a. The reducer is overloaded; b. The load of the working machine is unbalanced; c. The lubricating oil is deteriorated; d. The gear tooth surface is worn or the manufacturing quality is poor; e. The bearing clearance is too large or too small; There are adherents on the surface; g. There are sundries in the box;

6.2. Prevention and elimination methods: a. Operate according to the specifications; b. Adjust the balance state; c. Drain the deteriorated lubricating oil in the reducer, clean it and replace the qualified lubricating oil. d. Send it to the repair shop for overhaul and replacement parts in time; e. Adjust the bearing clearance; f. Check and clean up; g. Drain the oil for cleaning;

7 Gear damage

7.1 Broken teeth

7.1.1. Reason analysis: gear fracture is divided into fatigue fracture and overload fracture. During the operation of gear transmission, the gear teeth are subjected to alternating loads for many times, and bending fatigue stress acts on the dangerous section of the tooth root, resulting in fatigue cracks at the tooth root. Under the action of alternating bending fatigue stress, fatigue cracks gradually develop. Expansion will eventually lead to bending fatigue fracture of gear teeth; during gear transmission, when the gear is subjected to short-term overload, or impact load, or the gear teeth are severely worn and thinned, overload fracture will occur.

7.1.2. Solution: increase the radius of the transition fillet of the tooth root and reduce the roughness value of the machined surface as much as possible, which can reduce the influence of stress concentration, increase the rigidity of the shaft and support, and ease the local load on the tooth surface. ; Make the core of the gear teeth have sufficient toughness; Appropriate strengthening treatment at the root of the gear can improve the fracture resistance of the gear teeth.

7.2 Gear pitting and spalling

7.2.1. Reason analysis: The reason for pitting corrosion and spalling on the gear surface is mainly due to insufficient contact fatigue strength of the gear. The difference between this kind of pitting and spalling and wear is that the metal is not worn away in the form of particles, but spalled in the form of a block, resulting in pitting on the tooth surface and seriously destroying the correctness of the tooth profile. The damage process is as follows: first, tiny cracks are generated on the tooth surface, and the lubricating oil enters the fatigue crack. After many times of repeated meshing, the cracks continue to expand and extend, and the lubricating oil continues to fill the deep cracks with the expansion and extension of the cracks. Until a small piece of metal flakes off the tooth surface. This phenomenon destroys the normal meshing performance of the gears. The main reasons for pitting corrosion on the tooth surface are:

a. Material, hardness and defects. The material of the gear does not meet the requirements; the main factor affecting the contact fatigue strength of the gear is the low hardness after heat treatment, which cannot guarantee the contact fatigue strength of the gear. In addition, defects on the tooth surface or inside are also one of the reasons for insufficient contact fatigue strength.

b. The gear accuracy is poor. Gear machining and assembly accuracy does not meet the requirements, such as poor meshing accuracy and poor motion accuracy. There is also too much error in the center distance of the housing of the arc gear.

c. The lubricating oil does not meet the requirements. The grade of lubricating oil used is wrong, the viscosity of the oil is low, and the lubricating performance is poor.

d. The oil level is too high. If the oil level is too high, the oil temperature rises higher, which reduces the viscosity of the lubricating oil, destroys the lubricating performance, and reduces the working thickness of the oil film.

7.2.2. Solutions: increase the hardness of the tooth surface, reduce the roughness value of the tooth surface, use a large displacement coefficient as much as possible, increase the viscosity of the lubricating oil and reduce the dynamic load, which can help prevent fatigue pitting corrosion on the tooth surface .

7.3 Gear wear

7.3.1. Analysis of the reasons: ① lack of oil; ② the lubricating oil is mixed with metal chips under wear, which will also cause tooth surface wear; ③ gear material does not meet the requirements, resulting in abnormal wear; ④ gear has blisters, pores and looseness There are defects such as insufficient spheroidization; ⑤ insufficient heat treatment hardness or no heat treatment; ⑥ gear meshing accuracy and motion accuracy can not meet the requirements; ⑦ arc gear is very sensitive to the error of center distance, especially the positive center distance Error, not only reduces the bending strength of the gear teeth, but also increases the sliding wear.

7.3.2. Solutions: increase the hardness of the tooth surface, reduce the surface roughness value, keep the transmission device and lubricating oil clean, ensure sufficient lubrication, add appropriate anti-wear additives to the lubricating oil, add several magnetic bodies in the oil tank, The metal particles in the lubricating fluid are adsorbed by the magnetic effect, which can reduce the metal particle content of the lubricating fluid.

8. Reducer series shaft

8.1. Cause analysis: The tandem shaft faults in the field are all manifested from the tandem movement of the input shaft. There are two main reasons for the serial axis:

a. It is because the broken teeth make the input shaft lose the axial restraint and the tandem shaft occurs;

b. The driven gear on the intermediate shaft is not tightly fastened to the shaft. In actual transmission, often due to insufficient interference between the driven gear and the intermediate shaft, the driven gear produces an axial series movement relative to the intermediate shaft, thereby causing the input shaft to move axially.

Therefore, insufficient interference is the main reason for the tandem shaft of the reducer. In addition, the steering of the reducer also has a certain influence on the tandem shaft.

c. The gear machining deflection causes the serial axis. Driven gear machining skew on the intermediate shaft can cause skew. The gear machining is positioned on the outer circle and the end face, while the gear assembly is positioned with the inner hole. Sometimes the inner hole is not concentric with the outer circle, or the inner hole is not perpendicular to the end face, which will cause the processed gear to be offset from the center line of the inner hole. incline. For this kind of skewed herringbone gear, the plane where the center line is located is not perpendicular to the axis. When the gear rotates once, a certain point on the center line will reciprocate axially once, forcing the input shaft to also reciprocate axially. Move once.

d. The gear helix angle error causes the serial axis. The two halves of the driven herringbone gear on the intermediate shaft and the output shaft will change the centerline of the herringbone gear due to the error of the actual helix angle, resulting in a series of shafts.

e. When the reducer is subjected to positive and negative torque, the tooth thickness error, uneven wear and premature wear of the tooth surface, and the deformation of the tooth back cause the serial shaft.

In the actual transmission, due to the different degrees of deflection of the two halves of the driven gears, for the input shaft, the axial string movement is the result of the combined effect of the different degrees of deflection of the two halves of the driven gears on the intermediate shaft. In addition, the driven gear on the output shaft also causes serial movement due to the gear machining deflection, but since the output shaft is fixed in the axial direction, the intermediate shaft is forced to move, thereby forcing the input shaft to move in series.

8.2. Solutions: Improve the strength of the gears, the manufacturing accuracy of the gears, and reduce the roughness values ​​of the gears and shafts. To improve the installation accuracy and tightness of the driven gear and the shaft, the most important thing is to achieve a reasonable interference fit.