The limit speed of fag bearing refers to the limit value of continuous rotation without Requirements And friction and heating causing burns. The limit speed of fag bearing is affected by many factors such as fag bearing size, type,
lubrication, accuracy, oil gap, load and so on, but the most important is the influence of lubricant and ambient temperature. When rotating at high speed, especially when the speed is close to or exceeds the limit speed recorded in the dimension table, the following matters should be paid attention to:
(1) Use high precision fag bearings;
(2) Analyze the internal clearance of fag bearing and consider the reduction of internal clearance of fag bearing caused by temperature rise;
(3) Analyze the lubrication mode. The lubrication methods such as circulating lubrication, jet Requirements And lubrication, oil mist lubrication and oil-gas lubrication suitable for high-speed rotation are adopted.
(4) Analyze the material type of cage. For high-speed rotation, copper alloy or phenolic resin is suitable for cutting cage. In addition, there are synthetic resin molding cages suitable for high-speed rotation;
For small machinery, you can rotate it by hand to confirm whether it rotates smoothly. Requirements And Inspection items include:
1. Whether the operation is not smooth due to foreign matters, scars and indentation;
2. Whether there is unstable torque caused by poor installation and poor processing of mounting base;
3. Whether the torque caused by too small clearance, installation error and seal friction is too large, etc.
However, for large machinery, Requirements And manual rotation is not allowed. Therefore, the power shall be cut off immediately after no-load startup, and the machinery idles. Check whether there is vibration, noise, contact of rotating parts, etc. after confirming that there is no abnormality, enter the power operation.
Power operation starts from no-load low speed and slowly increases to the rated operation under the specified conditions. Requirements And During the test run, the inspection items include: whether there is abnormal sound,
FAG bearing temperature change, lubricant leakage or discoloration, etc. If any abnormality is found, stop the operation immediately, check the machinery, and remove the bearing for inspection if necessary.
Fag bearing temperature check. Generally, it can be inferred from the external temperature of the bearing pedestal.
However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The temperature of fag bearing increases gradually Requirements And from the beginning of operation, and the temperature is usually stable after 1 ~ 2 hours.
If fag bearing is not installed properly, the temperature will rise sharply and abnormal high temperature will occur. The reasons are too much lubricant, too small bearing clearance,
poor installation, excessive friction of sealing device, etc. In the case of high-speed rotation, the wrong Requirements And selection of fag bearing structure and lubrication mode is also the reason.
Fag bearing sound inspection. The rotating sound shall be checked with stethoscope. If there is strong metal noise, abnormal sound and irregular sound, it indicates that it is abnormal. The causes of noise include poor lubrication, poor accuracy of shaft or fag bearing seat, bearing damage, foreign matter intrusion, etc.
(1) The method of using chemical additives and adding certain chemical additives to the lubricating oil can reduce the noise of bearings. For example, the additive noise of low-noise grease produced by the same factory in Tianjin can reduce the noise of original bearings by 3.9 dB and 9.2 dB, which is suitable for micro and small bearings.
(2) Absorber or vibration isolation device uses suction or vibration isolation device to reduce noise, or isolate bearing fag bearing noise and achieve good results. Requirements And However, it often pays a high price in economy. Sometimes, for large mechanisms, changes in thermal conditions, or easy to rust,
it should be considered thoroughly before taking other measures, To achieve the goal of low noise and can not be used in the future. A simple example is high speed, not thrust bearing and thrust centripetal thrust bearing or the shell of thrust bearing. The ball bearing absorbs the anti rust lubricant of plastic jacket in the outer ring,
which allows the plastic insertion of cylindrical hole in general, or in the same group, but uncontrollable rotation and adjacent mechanical friction or interference. This Requirements And method has a certain effect on the muffler. Another example is to add a setting hole between the bearing and the middle of the seat.
You can spread the attenuation of the bearing seat rotation system of the vibration force, but it needs to be deployed properly, or it may have the opposite effect.
Another example is the use of acoustic acoustic coverage to completely close the system, or turn it off. This internal noise reduces the internal surface of 0.6 LMM thick steel plate, glass fiber or polyurethane foam, small uniform on the surface. φ 1.2 – 1.5mm hole,
the total area of the hole is about 25% to 30% of the whole inner surface, and the thickness of the steel plate on the outer surface is 2mm. Used to eliminate high frequency noise, with the inner surface of the hole to eliminate low-frequency noise, such fiberglass or foam, the outer surface of thick steel plate is used to isolate noise rumors.
(3) The method of changing the corresponding part of the fag bearing noise of the main engine is not very sensitive to the load, but the speed is very sensitive. If the conditions allow, reduce the speed and increase the torque to achieve the same working purpose,
but it reduces the noise. In order to reduce the noise of the pump system, the speed of the motor originally used was 1430r / min, the flow rate was 10L / min, and the speed was 710r / min. the motor and the pump with larger size and the rear pump itself got the same flow pump bearing.
The noise of the bearing of the oil pump motor was significantly reduced, but the footprint of the whole organization was expanding, and the cost was also increased.