There are two complex issues with bearing maintenance technology: when and how much oil should be changed.If the oil is too little, the bearing will be scrapped in advance;If too much oil is changed, the bearings can get bogged down or permanently damage the power coils and coils.
Traditionally, the lubrication schedule is based on time.The equipment supplier usually makes the lubrication plan according to the operation time.In addition, equipment suppliers often include guidance on the quantity of lubricants in their maintenance plans.For staff, short - term change of lubricating oil is very common thing, and often add too much grease.For example, ask staff to change the oil every two to three weeks and add one ounce of grease each time.These recommendations lead them to be built on unknowns that have no real meaning.
The lubrication interval has a simple premise: the proper operation of the equipment is maintained under the condition that the bearing does not stop operation due to drying and collapse.It's a fixed concept of prevention.However, we must maintain a balance between a thirst for lubrication and a great deal of over-lubrication.
In order to optimize the equipment, it is better to know when to lubricate and when to stop refueling the bearings.This can be achieved by setting lubrication strategies according to the conditions.Simply put, the condition of the bearing determines when to change the oil.When the bearing is running smoothly and there is no indication that the bearing is changing, lubrication should be avoided to allow it to run normally.If conditions change or the bearing shows a need for lubrication, lubricants should be used.Testing the bearings and changing the oil can help us decide how much oil to add and when to stop.
Ultrasonic technology is an ideal effective way to lubricate under conditions.To understand why, we must understand the ultrasonic technology, how the bearings produce ultrasonic waves, and how the ultrasonic instruments help us maintain the optimal lubrication strength on the bearings.
Ultrasonic technology is measured according to the high frequency of sound induction.Ultrasound is 20,000 revolutions per minute or 20,000 Hertz.Consider that when people's hearing frequencies stop, high-frequency ultrasound is just beginning.Most ultrasonic instruments can sense anything from 20 to 100KHZ.People's hearing ranges from 20HZ to 20KHZ.The average person can often hear up to 16.5KHZ or more.
The instrument based on the ultrasonic technology of structural frame refers to the ultrasonic converter.They used Heterodyning technology to electronically convert high frequency sounds that are not audible to the human ear into a range that is audible to the human ear.This heterodyning technique is as simple as the working principle of AM on a radio.When we listen to the radio, we can't hear the sound waves of the radio, but this way can help us easily distinguish different sounds and Musical Instruments.
In simple terms, the technical process provides a precise ultrasonic conversion function that converts the sound of the operating device into a sound that the user can immediately identify, thus identifying the sound of different components.Most ultrasonic transducers feed back sound in one of two ways: by amplifying the sound through an audio system or by a measuring device to amplify it or to reach a certain decibel level, people can hear it.
Suppose you have an installed bearing.Add the appropriate amount of oil at a reasonable schedule.When it is on the track, any pressure it may experience is broken down by the oil, that is, there is no pressure at all.If so, the sound produced by the bearing is like the sound of a flat tire.We call this "white noise".This kind of noise includes all kinds of sound, high and low frequency.High frequency sound waves are easier to recognize than low frequencies.With ultrasonic transducers, these signals can be distinguished from other components that emit mechanical noise or from small amounts, such as tool bars or adjacent bearings.(the ultrasonic transducer will detect friction, as opposed to the vibration meter, which detects the vibration of moving elements.)
When the bearing lubrication strength fails or deteriorates, the potential for friction increases.You will notice or hear that the intensity of the ultrasonic amplification increases accordingly.The way to decide when to lubricate and when to stop oiling is very simple: lay out a base line, make an observation schedule, and monitor when oiling.
Make a base line
The bearing base line reflects the db strength under normal operation, no visible errors, and sufficient lubrication conditions.There are three ways to make a foundation line:
1. Comparison method: if there are multiple bearings of the same type, these bearings can be put together for comparison.Use the same test method or view each bearing from the same Angle.Analyze decibel intensity and sound quality.If there is no essential difference (less than 8 db), we can set it to the base db strength of each bearing.
2. Set the base line when adding lubricating oil: when adding lubricating oil, listen to the sound intensity, when the sound intensity drops and then rises again.At this point, do not add too much oil, and set it as the base line.
3. Historical records: the db strength of the bearing was observed and recorded every day, and then the results were compared for 30 days.If there is little or no change in db intensity (less than 8 db), we can set this as the base line and use it as a comparison value for later observations.
Set an observation schedule
For example, equipment critical to total production, environmental results, and operational results is the primary factor in selecting and setting the evaluation machinery system.Once a month is necessary when the basic observation line is established.For high-decibel bearings to be lubricated, they should be detected more frequently so that changes can be observed.If a bearing is in a state of impending failure, the lubricant can only temporarily cover up the error.However, the decibel level can quickly rise to indicate the presence of an error.In some cases, it can take minutes, in others days.
Lubrication time detection
If the decibels of a bearing exceed 8 decibels of the base line, we consider that the bearing needs lubrication.When we realize that the bearing needs lubrication, knowing when to stop oiling will prevent excessive lubrication.Follow these three steps:
1. Calculate the dosage based on the bearing manufacturer's instructions, and then inject lubricating oil, not too much.This procedure is very subjective, has nothing to do with ultrasound, and has never failed.
2. When the lubricating oil is injected, the lubrication technician USES the ultrasonic instrument to detect the bearing.Oil slowly until the decibel level drops to the base level.
3. If there is no base line as a guide, the use of lubricating oil should stop when the sound level is lowered and then rises again.At this point, the technician should stop using the oil.
Ultrasonic bearing inspection
Ultrasonic inspection or monitoring is the most reliable way to detect early (initial) bearing damage.When the temperature rises or the intensity of the low-frequency vibration increases, the ultrasonic warning will sound first.This method of inspection is useful in the early stages of bearing damage due to overuse, lack of lube oil or excessive lube oil.
Detect signs of failure
Ball bearings, such as rollers or ball bearings, like the metal on the track, will begin to deform slightly when overused.This creates an irregular surface, which results in an increase in the emission of ultrasonic waves.Changes in amplitude from initial readings indicate one or two conditions: early failure or lack of lube oil and initial bearing failure.If the ultrasonic exceeds the base line by eight decibels, it is accompanied by a sustained impact noise, which indicates a failure of the lubricant (dry bearing surface).If the ultrasonic reading exceeds the expected reading and reaches 12 decibels, there is a crash noise, which can be assumed that the bearing has started to enter failure mode.