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A high-speed bearing fit and clearance due to high-speed bearings to high precision bearing requirements, but also by high temperature bearings SKF bearings in the request, so consider the fit and clearance, to consider the following two points:
(1) change from room temperature to changes in the size and hardness at high temperature;
(2) force line change and shape change under high-speed centrifugal force caused by.
In short, in the high speed, high temperature conditions, and with clearance from the selection of want to maintain the bearing accuracy and performance, this is difficult.
In order to ensure the bearing after installation of the rolling deformation is small, the amount of interference can not fit the too big, and high-speed centrifugal force and under the high temperature thermal expansion, or set off with the normal surface pressure. Or is the mating surface relaxation, so the amount of interference must be in consideration of the above two factors under the carefully calculated, the effective amount of interference may be ineffective for high-speed bearing at normal temperature and velocity.
If the results of this contradiction is too large (usually have only in the ultra high speed), only to take double lubricating measures ring lubrication and lubrication method and use, mark and this scheme is likely to make bearing DMN value above 3000000.
Considering the high speed bearing clearance not only to consider the various factors mentioned above, but also to consider the impact of thermal elongation axis on the clearance, requirements of the bearing under the working state, which has the best clearance at operating temperature, this gap is formed in the inner, outer ball groove center precision condition. Due to the high speed bearings to reduce the relative sliding and internal friction, clearance is best not to use methods within the outer ring along the axial direction, relative displacement to adjust the ball bearing. In considering the bearing interference fit and clearance, should pay attention to the characteristics of material at high temperature has become soft and easy to deformation, and the possibility of many from the normal temperature to high temperature change caused by a permanent deformation.
Two the host related parts of the requirements.
High speed bearings require bearing the rotary system through the dynamic balance precision, shaft and hole installation of bearing parts should be higher than the general requirements for accuracy of size and form, especially the concentricity and verticality abutment seat hole or shaft neck, and in considering these questions, must also pay attention to high speed factors bearing in operation and the temperature factor.
Shaft bearing system requires high rigidity, and quality requirements as far as possible light, in order to overcome this contradiction, can take such as decreasing the surface roughness and surface strengthening measures to improve the supporting stiffness, the hollow shaft to reduce the system quality.
Three. Development of ultra high speed bearing development example is to ultra high speed HA tapered roller bearing as an example.

(1) the problem
In the gas turbine and some machine and engineering machine, high speed and axial load SKF bearing large, using ball bearings is used to have a short life, the use of short cylindrical roller bearing the axial load capacity is insufficient, the axial clearance is difficult to adjust, hope to use tapered roller bearings breaks the problem.
(2) the key technologies must be solved
The key technology to improve the tapered roller bearing high speed limit lies in the improvement of cone gear lubrication between the edge and the roller large end face, the site at high speed when the most prone to severe wear and burn, is the main reason for limiting the speed of.
(3) solution
The general structure of the tapered roller bearing, lubricating oil flow route in the cone gear contact parts and roller large end face is very difficult to get the oil, and the region of relative sliding, it most in need of lubricating oil.
Therefore, Japan and other countries to develop HA tapered roller bearing, the bearing rib in the outer loop, such circulating lubricating oil lubricant can ring rib and roller large end face contact parts, at the same time here even when still can also store some oil, to avoid starting lean burn accidents, but the outer edge. According to the need to open several oil drain hole, in order to avoid oil without discharging channel, a part of power losses caused by retention in temperature and oil mixing rises too high.
As the inner ring without ribs, lower temperature, thus reducing the between the inner ring and shaft with the possibility of creep surfaces. This bearing structure of the outer ring retainer guide mode, the retainer can smoothly guide roller not askew in normal operation, to avoid the occurrence of vibration and excessive wear, which is also conducive to high speed.
(4) can achieve the effect of
The HA bearing DMN value up to 2000000, higher than the two times of the ordinary structure, for example for the bearing gas turbine reducer spindle (model I-IA30205), in the axial load 1000N, ensure that 2L / min oil on bearing recycle supply No. 4 turbine oil, its working speed up to 60000 to avoid burns.