The inspection items during the operation of motor bearings include the sound, vibration, temperature, and other states of the bearings during operation. The specific situations are as follows:
The sound of bearing operation
If the bearing makes abnormal noise during operation, it may be due to quality issues of the bearing itself or other reasons. Today, I will share with you a summary of the reasons for the abnormal noise of the bearing, hoping to be helpful.
Bearing noise in different situations and solutions
1. If the bearing is in good continuous running condition, it will emit a low moaning or buzzing sound. If sharp hissing, creaking, and other irregular sounds are emitted, it often indicates that the bearing is in poor continuous running condition. Sharp squeaking noise may be caused by improper lubrication. Inappropriate bearing clearance can also cause metal noise.
2. Dents on the outer ring track of the bearing can cause vibration and create a smooth and crisp sound.
If there is intermittent noise, it indicates that the rolling element may be damaged. This sound occurs when the damaged surface is rolled, and if there are pollutants inside the bearing, it often causes a hissing sound. Severe bearing damage can produce irregular and loud noise.
4. If the impact marks caused during installation also produce noise, this noise will vary with the speed of the bearing.
► Large metal noise
Reason 1: Abnormal load
Countermeasure: Study the bearing clearance, adjust the load, and correct the position of the housing shoulder.
Reason 2: Poor installation
Countermeasure: Improve the machining accuracy of the shaft and casing, improve the installation accuracy and method.
Reason 3: Insufficient or unsuitable lubricant
Countermeasure: Supplement lubricants and choose appropriate lubricants.
Reason 4: Rotating parts have contact
Countermeasure: Modify the contact part of the curved road seal.
► Regular noise
Reason 1: Indentation, rust, or scratches on the rolling surface caused by foreign objects
Countermeasure: Replace bearings, clean relevant parts, improve sealing devices, and use clean lubricants.
Reason 2: Surface deformation (after steel carburization)
Countermeasure: Replace the bearing and pay attention to its use.
Reason 3: Peeling of the raceway surface
Countermeasure: Replace the bearings.
Irregular noise
Reason 1: Excessive clearance
Countermeasure: Study the fit and bearing clearance, and modify the preload.
Reason 2: Foreign object invasion
Countermeasure: Replace bearings, clean relevant parts, improve sealing devices, and use clean lubricants.
Reason 3: Spherical injury and peeling
Countermeasure: Replace the bearings.
Vibration of bearings
The main reasons for bearing vibration are:
1. Vibration of rolling elements. After the bearing bears the load, the rolling element vibrates during rotation due to changes in its position and load, resulting in different elastic deformations at the contact area. The larger the radial clearance, the greater the vibration of the bearing; As the number of rolling elements increases, the vibration value will decrease, and the vibration will increase at high speeds.
2. The waviness of the rolling surface of bearing parts causes vibration. Waviness is the surface roughness generated during the manufacturing process of bearing parts, which is the main cause of noise and vibration. Compared to bearing rings, rolling elements, and retainers, the most influential factor is the waviness on the surface of the rolling element, followed by the waviness on the surface of the rotating ring raceway, and once again, the waviness on the surface of the stationary ring raceway.
3. Vibration caused by the roughness of the rolling surface of bearing parts. The roughness of the rolling surface of bearing parts also affects the vibration of finished bearings. When the rolling surface roughness Ra value is greater than a certain value, the vibration value of the finished bearing will significantly increase. If there are irregular grinding marks on the rolling surface locally, the vibration impact on the finished bearing will be greater.
4. Vibration caused by the cage. The large roughness value and irregular shape of the inner surface of the cage pocket hole can cause friction and increase the vibration of the bearing.
5. The scratches on the rolling surface of bearing parts cause vibration. The presence of collisions, jamming, scratches, or other defects on the rolling surface of bearing parts can cause impact and are the direct cause of vibration and noise in finished bearings.
6. The internal dirt of the bearing causes vibration. The finished rolling bearings may experience varying degrees of vibration or noise due to poor cleaning or the invasion of harmful substances such as dirt during transportation and installation.
Several sources of rolling bearing noise
1. Rolling friction sound. The frictional sound generated by rolling elements on the raceway is the basic sound of bearings. But the size of the sound is related to the structure of the rolling bearing. For example, the sound of ball bearings is lower than that of roller bearings, the sound of bearings in the light series is lower than that in the specific gravity series, the sound of bearings with a large number of rolling elements is lower than that of bearings with a small number of rolling elements, and the sound of precision bearings is lower than that of ordinary bearings.
2. sliding friction sound. Intermittent sliding friction sound between the rolling element or ring and the cage.
3. Impact vibration sound. There are scratches or defects on the rolling surface that cause a knocking sound during rotation. Dirt and dust invading the rolling surface of bearings can also generate friction and impact sounds.
Temperature during bearing
When the ambient temperature is 40 ℃, the maximum operating temperature of the motor cannot exceed 120/130 ℃. The maximum allowable bearing temperature is 95 degrees.
Reasons and solutions for excessive bearing temperature rise
Reason 1: The shaft is bent and the centerline is not accurate.
Countermeasure: Find the center again.
Reason 2: The foundation screws are loose.
Countermeasure: Tighten the screws.
Reason 3: The lubricating oil is not clean.
Countermeasure: Replace the lubricating oil.
Reason 4: The lubricating oil has been used for a long time and has not been replaced.
Countermeasure: Clean the bearings and replace the lubricating oil.
Reason 5: The ball or roller in the bearing is damaged.
Countermeasure: Replace with a new bearing.