news

The installation of the high-speed bearing, cooperate and adjustment
  1. The matching of the high-speed bearing and clearance due to the high speed bearing should be in accordance with the requirements of high precision bearings and in accordance with the requirements of high temperature bearing so when considering its coordination and clearance, to consider the following two points: (1) from normal temperature to high temperature hardness for the size of the change and change;(2) under the high speed centrifugal force caused by the force system and shape changes.All in all, under the condition of high speed, high temperature, from the choice of coordination and clearance to strive to maintain the accuracy of three Thai bearing and work performance, it is difficult.To ensure the bearing raceway deformation after the installation is small, the amount of interference interference fit can't get too big, and under the high speed centrifugal force and high temperature thermal expansion, or on the surface of the offset with the normal pressure.Or make matching surface loose chi, thus interference quantity must under the premise of considering these two factors determine prudently, effectively under the constant velocity of the amount of interference for high-speed bearing may be invalid.Calculation result if the conflict is too big (usually it happens only under ultra-high speed), only under the ring lubrication and hydrostatic lubrication and lubrication measures, and this scheme has the potential to hit the 3 million mark DMN value of the bearing.When considering three Thai high-speed bearing clearance not only should consider the above-mentioned factors, and to consider the influence of the axial thermal elongation of clearance, the demand bearing under working state, namely in the working temperature is the best clearance, clearance is, and this, the outer ring groove ball center accurate registration form of the condition.Due to the high speed bearing makes every effort to reduce the relative sliding and internal friction, had better not use relative displacement of the inner and outer ring along the axial approach to adjust clearance of ball bearings.Considering the amount of the interference with the bearing clearance, and be aware that materials at high temperature becomes soft and easy to deformation characteristics, and many times caused by the temperature change of normal temperature to high temperature must be the possibility of permanent deformation.2. To host demands high-speed bearing bearing of related parts precision rotary system of dynamic balance, shaft and hole bearing installation of the parts should be higher than the general requirements of dimensional accuracy, form and position accuracy, especially the alignment of hole or shaft neck and shoulder vertical degree, and to think about these problems, also must pay attention to the high speed and high temperature factors in the operation of the bearing.Shaft bearing system requires both high rigidity, asked for a light quality as much as possible, in order to overcome the contradiction, can take measures such as reducing the surface roughness and improve the surface strengthening in order to improve the bearing stiffness, using hollow shaft to reduce the system quality, etc.3. The development of ultra high speed bearing instance, enclosed with ultra-high speed HA type development of tapered roller bearing, for example.(1) the problem put forward in the gas turbine and some machine and engineering machinery, high speed and large axial load, the use of the service life of the ball bearing is too short, use three Thai short cylindrical roller bearing axial load can force is insufficient, the axial clearance is difficult to adjust, hope to make use of the tapered roller bearing break through this difficult problem.(2) must solve the key technology of improving taper roller bearing is the key of the technology of high speed limit to improve inner ring guard and lubrication condition between the roller large end face, this area the most easily when high-speed developing severe wear and burns, is the main original high speed limit its cause.(3) solution in the general structure of the tapered roller bearing, lubricating oil circulation route of big guard ring and roller large end face contact parts are hard to come by lubricating oil, explained and the relative sliding, precisely and lubricating oil are needed most.Therefore, Japan and other countries have developed HA type of tapered roller bearings, the bearing guard in the outer ring, so that the circulation of lubricating oil can lubrication outer rim roller and the big end surface contact area, even at rest here at the same time also can save some oil, to avoid the inferior burns accident when starting, but the outer rim according to need to open a few of drainage holes, no discharge channel, to avoid oil retention in some oil mixing power loss and temperature rise too high.As there is no guard inner ring, the temperature decreases, and thus reduce the matching surface between inner ring and the shaft between the possibility of peristalsis.The structure of the bearing outer ring guided mode to the cage, the cage can be smoothly guide roller is not crooked Inclined to normal operation, to avoid vibration and excessive wear, this also is helpful for high speed.(4) can achieve the effect of the HA type three Thai bearing DMN value of up to 2 million, twice higher than that of normal structure, such as main shaft of the bearing used in gas turbine reducer (model I - IA30205), under the condition of the axial load of 1000 n, ensure that there is 2 l/min to implements cycle for bearing oil supply 4 turbine oil, the working speed of up to 60000 turn there is burned.