Raceway noise is a kind of stable and continuous noise excited by the rolling body rolling in the Raceway Noise raceway when the IKO bearing rotates. People pay attention to it only when its sound pressure level or tone is extremely high.
In fact, the sound energy excited by the raceway sound is limited. For example, under normal Raceway Noise conditions, the high-quality 6203iko bearing raceway sound is 25 ~ 27db. This noise is typical of single row deep groove ball IKO bearing bearing bearing bearing bearing radial load. It has the following characteristics:
a. Noise and vibration are random;
b. The vibration frequency is above 1kHz;
c. No matter how the rotating speed changes, the main frequency of noise is almost Raceway Noise unchanged, while the sound pressure level increases with the increase of rotating speed;
d. When the radial clearance increases, the sound pressure level increases sharply;
e. When the rigidity of IKO bearing pedestal increases, the lower the total sound pressure level is, even if the speed increases, the total sound pressure level does not Raceway Noise increase much;
f. The higher the viscosity of lubricant, the lower the sound pressure level, but for grease Raceway Noise lubrication, its viscosity and the shape and size of soap fiber can affect the noise value.
The rolling sound is caused by the natural vibration of the ferrule after being loaded. The elastic contact between the ferrule and the rolling body constitutes a Raceway Noise nonlinear vibration system.
When the lubrication or machining accuracy is not high, the natural vibration related to this elastic feature will be excited, and when it is transmitted to the air, it will become noise. As we all know, even if IKO bearing parts are processed with contemporary superb manufacturing technology,
there will always be small geometric errors in varying Raceway Noise degrees on the working surface, resulting in small fluctuations between the raceway and the rolling body and exciting the natural vibration of the vibration system.
Although the raceway noise of IKO bearing is inevitable, the correct selection of IKO bearing and accurate use of IKO bearing can reduce noise and vibration when adopting high-precision machining of parts’ working surface.
The advantages of using lubricating oil for rolling fag bearings are:
1) Under certain operating specifications, the starting torque and friction loss of lubricating oil are significantly smaller than that of grease lubrication.
2) As the lubricating oil takes away heat in the circulation and plays a cooling role, it can make the fag bearing reach a relatively high rotation speed.
3) It can ensure relatively high service temperature.
4) When changing grease, relevant connecting parts must be disassembled. When lubricating with oil, there is no such trouble.
5) When the fag bearing in the reduction gearbox is lubricated with lubricating oil, it is very suitable, because the oil can simultaneously lubricate the gear and fag bearing in a splash way.
6) In fag bearings, the lubricating grease is gradually contaminated by the products of product wear, abrasives, products penetrating through the sealing device from the outside and aging itself.
If it is not replaced in time, it will cause accelerated wear of fag bearings. When liquid lubricant is applied, it can be filtered to ensure its normal operation.
Advantages of grease lubrication for rolling fag bearings:
1) Individual fag bearing points must be refueled frequently by hand. If the grease is changed, it will not only save trouble, but also avoid accidents caused by lack of oil.
2) The grease itself has a sealing effect, which allows the mechanism with low sealing degree to be used to simplify the design.
3) Experience has proved that in a certain speed range (n < 20000 R / min or DN < 20000 mm. R / min), lubrication with lithium grease has lower temperature rise and longer service life of fag bearing than oil dropping method.
2. Theoretical basis of rolling fag bearing lubrication: the lubrication mechanism of rolling fag bearing belongs to the theory of elastic fluid hydrodynamic lubrication.
3. Relationship between failure types and lubrication of rolling fag bearings: most failure causes are damage caused by faulty assembly and poor sealing. A few failures are caused by wear, gluing, corrosion and overheating caused by lack or excess of lubricant or unqualified quality.
4. Basic characteristics of lubricating grease and general criteria for selecting lubricating grease:
When selecting lubricating grease, it is necessary to select the lubricating grease suitable for the service conditions (temperature, speed, load and environment, etc.), which are related to the basic characteristics of lubricating grease, and the basic characteristics of lubricating grease depend on the type of thickener and base oil.
Rolling fag bearings have both rolling friction and sliding friction. Sliding friction is caused by the deviation of rolling fag bearing on the surface curve and the deformation of fag bearing under load.
For example, between the rolling element and the ring, because the ball and the ring are not absolute rigid bodies, their contact area will always produce elastic deformation. In theory, it is point contact or line contact, but in fact, it will always become surface contact under load working conditions.
Therefore, the contact points with different diameters have different linear velocities, resulting in sliding friction. Similarly, due to various reasons, sliding friction will also occur between the rolling element and the retainer, as well as between the retainer and the inner and outer rings.
The sliding friction increases with the increase of speed and load. In order to reduce friction, wear, reduce temperature and noise, prevent the parts of fag bearing from rusting, correctly select lubricants and adopt reasonable lubrication methods,
and appropriately control the amount of lubricants are important topics to improve the service life of fag bearing.
The above is the comparison of the effect of grease lubrication and oil lubrication in rolling fag bearings. I hope you can have some experience after it appears.