The two big complexities of bearing maintenance technology are 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 into trouble or damage the power coils and coils for a long time.
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 amount of lubricants in their maintenance schedules.It is very common for employees to change the lubricating oil for a short period of time, and more grease is often added.For example, ask staff to change the oil every two to three weeks and add one ounce of grease each time.These recommendations in the first place lead them to be based on unknown factors that have no practical significance.
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.This is a fixed concept of prevention.However, we must maintain a balance between a thirst for lubrication and a lot of excessive lubrication.
In order to achieve the goal of optimizing the equipment, it is good 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 the oil is changed.When the bearing runs smoothly and there is no indication that the bearing has changed, 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 according to conditions.To understand why, we must understand the ultrasonic technology, how the bearing produces the ultrasonic wave, and how the ultrasonic instrument helps us maintain the optimal lubrication strength on the bearing.
Ultrasonic technology is measured according to the high frequency of sound induction.Ultrasound spins at 20,000 cycles per minute, or 20,000 Hertz.Consider that when people's hearing frequencies stop, high-frequency ultrasound just starts.Most ultrasonic instruments can sense between 20 and 100KHZ.People's hearing ranges from 20HZ to 20KHZ.The average person often hears up to 16.5KHZ or more.
The instrument based on the structural frame ultrasonic technology refers to the ultrasonic converter.They used the Heterodyning technique to electronically convert high frequencies that are not audible to the human ear into a range that is audible to the human ear.The heterodyning technique is as simple as the radio's AM.When we listen to the radio, we can't hear the sound of the radio waves, but this way can help us easily distinguish different sounds and Musical Instruments.
In short, the technical process provides a precise ultrasonic conversion function that converts the sound produced by the operating device into a sound that the user can immediately identify, so that the sound produced by different components can be identified.Most ultrasonic transducers feed back sound in two ways: by amplifying the sound with a sound system or by measuring it with a 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 lubricating oil under reasonable arrangement.When it runs on the track, any pressure it is subjected to is broken down by the oil, that is, there is no pressure.If so, the sound produced by the bearing is like the sound of a flat tire.We call this noise "white noise".This noise consists of various sounds, high and low frequencies.High frequency sound waves are easier to recognize than low frequencies.With ultrasonic transducers, these signals can be distinguished from mechanical noise emitted by other components, such as tool bars or adjacent bearings, or from small amounts.(the ultrasonic transducer will detect friction, as opposed to the vibration meter, which detects the vibration of moving components.)
When the bearing lubrication strength fails or deteriorates, the potential for friction increases.You will notice or hear an increase in the intensity of the ultrasonic amplification.The way to decide when to lubricate and when to stop oiling is simple: make a base line, make an observation schedule, and monitor while oiling.
Make a base line
The bearing base line reflects the decibel 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 as 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 record: observe the db strength of the bearing, record it every day, and then compare the results of 30 days' record.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 future observations.
Set an observation schedule
For example, equipment critical to total production, environmental results, and operational results is a major factor in the selection and setting of evaluation machinery systems.Once a month inspection is necessary after the basic observation line is established.For high-decibel bearings to be lubricated, it should be checked more frequently so that changes can be observed.If a bearing is in a state of near destruction, 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 lubricating oil is injected, the lubrication technician shall use ultrasonic instrument to detect the bearing.Oil slowly until the decibel level drops to the base line.
3. If there is no base line as a guide, the amount of lubricating oil should be stopped when the sound decreases and then increases.At this point, the technician should stop using the oil.
Ultrasonic bearing inspection
Ultrasonic inspection or monitoring is the most reliable way to detect bearing damage in the early stages.When the temperature rises or the intensity of the low-frequency vibration increases, the ultrasonic warning is the first to sound.This method of inspection is useful in the early stages of bearing damage due to overuse, lack of lubricating oil or excessive lubricating oil.
Detect signs of failure
Ball bearings, such as rollers or ball bearings, like the metal on the track, can become slightly deformed when they are overused.This produces an irregular surface, which leads to an increase in the amount of ultrasonic emission.The change in amplitude from the initial reading indicates one or two conditions: early failure or lack of grease and early bearing failure.If the ultrasonic wave 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 to 12 decibels, there is a crash noise, which can be assumed that the bearing has started to go into failure mode.