For bearing speed many people still have some understanding, the so-called bearing limit speed refers to the bearing large allowable speed, which is with the bearing diameter series and width of the series of incremental decrease. Each kind of rolling bearing speed, have a certain limit. When the bearing rotates, the temperature rise generated by the internal frictional heat of the bearing increases as the rotational speed increases. The speed limit is an empirical speed tolerance value for continuous operation without sticking and overheating. Therefore, the limiting speed (rpm) of various bearings varies according to the bearing structure, size, cage structure, material, bearing load, lubrication method, including the cooling condition of the periphery of the bearing.

The following China bearing network lists, about rolling bearing limit speed of some factors

1, lubrication method: the use of oil and gas or oil mist lubrication bearings can be uninterrupted supply of trace amounts of new lubricant to the bearing, effectively guarantee the thickness of the bearing lubricant film. And the spray lubrication mode due to a large number of oil supply, can quickly take away the heat generated by the bearing operation, improve the limit speed of the bearing.

2, bearing load: rolling bearing limit speed in a certain load, lubrication conditions to achieve high speed, with bearing type, size, direction, lubrication, game, cage structure, cooling conditions, load (size, type, direction) and so on have a great relationship.

Improve the bearing precision, proper adjustment of bearing clearance can improve the ultimate speed of deep groove ball bearings.

3, preload: bearing in the installation if the preload is too big will lead to bearing in the operation of the rolling body and raceway surface between the contact stress increases, heat followed by improve, and then lead to the bearing internal preload further increase, so that the bearing is more prone to wear and reduce the limit bearing.

4, drive mode: the limiting speed of the bearing will change with the different spindle drive mode, for example, when the use of electric spindle drive, the spindle internal heat generation is larger, if the use of the outer cylinder cooling at the same time, it will lead to the bearing of the inner and outer rings of the temperature difference between the larger, increase the internal load of the bearing, resulting in the reduction of the limiting speed; use of the outer cylinder cooling due to the bearing housing of the different tolerances of the housing, bearings and housings, the different amount of thermal expansion, the outer ring fit from a clearance fit to the outer ring fit to a different thermal expansion. Outer ring fit from clearance fit into interference fit, internal preload increase and lead to changes in limiting speed.

5, the size of the bearing clearance: bearing installation clearance for a small negative value, the rated life is long, load carrying capacity and limiting speed is also high, but because the actual clearance should also be subtracted from the fit of the interference and the deformation caused by the temperature difference, this small negative clearance is difficult to control, and once the clearance is too much negative rated life will be significantly reduced, so, at present, generally is close to the selection of the 0 positive clearance.

6, bearing combination: bearing combination, due to a large number of oil supply, can quickly take away the heat generated by the bearing, limit speed can be further improved.

Bearing limit speed correction

In the bearing load P exceeds the basic rated dynamic load of 8%, or axial load F exceeds the radial load F.20% of the working conditions, it is necessary in the bearing size table recorded on the limit speed, multiplied by the correction coefficient, in order to correct the limit speed.

The bearing speed exceeds the limit speed of the working conditions, the bearing precision, (internal) clearance, cage structure, materials, etc., after a full study of the selection of lubrication methods must be taken to forced circulation lubrication, jet lubrication, spray lubrication or oil and gas lubrication, and so on.

Adoption of the above high-speed countermeasures, can improve the limiting speed. In other words, it is possible to reach the limiting speed of oil lubrication recorded in the bearing dimension table multiplied by the correction factor.