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Bearing selection is not right, do not say the bearing quality bad

Bearing selection is not right, do not say the bearing quality bad
Issue Time:2018-08-15

" varioustypes of bearings have different characteristics due to different designs. Dueto the bearing's specific location of installation and the variability andcomplexity of application, bearing type selection without fixed mode can beused to adapt to a certain host specific location of installation andapplication conditions for bearing type selection, it is recommended to takecomprehensive consideration according to the following main factors."


Allow space
Mechanical design,generally determine the size of the shaft first, and then choose the bearingaccording to the size of the shaft. Generally, ball bearings are used for smallshafts. Cylindrical roller bearings, centering roller bearings, tapered rollerbearings (ball bearings are sometimes used) are used for the big shaft. If theradial space of bearing mounting position is restricted, bearings with smallerradial section height should be used. Such as needle roller bearings, certainseries deep groove ball bearings, angular contact ball bearings, cylindrical orcentering roller bearings and thin wall bearings. If the axial space of thebearing mounting position is restricted, the bearing with a smaller width canbe used.


Bearing load
The load size isusually the determinant of the bearing size. The bearing capacity of rollerbearing is larger than that of ball bearing with the same dimension. Ballbearings are generally used for light or medium loads and roller bearings forheavy loads.
Deep groove ballbearings and cylindrical roller bearings can be used for pure radial loads.Thrust ball bearing and thrust cylindrical roller bearing can be selected forpure axial load. Angular contact ball bearings or tapered roller bearings arecommonly used when radial and axial loads (combined loads) are available. Ifthe radial load is large and the axial load is small, bearing man WeChatprofessional! Deep groove ball bearings and cylindrical roller bearings withinner and outer rings with baffles can be selected. If at the same time theshaft or shell deformation is large and the mounting pair is neutral,adjustable ball bearings and roller bearings can be selected. If the axial loadis large and the radial load is small, the thrust Angle contact ball bearingcan be selected. If four-point contact ball bearing still requires centeringperformance, the thrust adjusting roller bearing can be selected.


speed
The working speedof the rolling bearing mainly depends on the allowable operating temperature.Bearing with low friction resistance and less internal heat is suitable forhigh speed operation. When only bearing radial load, deep groove ball bearingand cylindrical roller bearing can reach high speed. If bearing combined load,angular contact ball bearing should be selected. Special designed highprecision angular contact ball bearing can achieve high speed. The speed of allkinds of thrust bearings is lower than that of radial bearings.
Rotation accuracy
For the majority ofmachinery, choose a level 0 tolerance of bearing is enough to meet therequirements of the host, but on the axis of rotation accuracy have strictrequirements, such as spindle, precision machinery and instrument etc., shouldchoose high tolerance grade of deep groove ball bearings, angular contact ballbearings, tapered roller bearings, cylindrical roller bearings and thrustangular contact ball bearings.


rigid
The rigidity ofrolling bearings is determined by the elastic deformation under load.Generally, such deformation is very small and can be neglected. However, insome machines, such as machine tool spindle system, static and dynamicstiffness of bearings have great influence on the characteristics of thesystem. Bearing man WeChat professional! Generally speaking, roller bearingshave higher stiffness than ball bearings. Various types of bearings can also beproperly "preloaded" to increase stiffness to varying degrees.
Noise and vibration
The noise andvibration of the bearing itself are generally very low. However, for small andmedium sized motors, office machines, household appliances and instruments thathave special requirements for noise and smooth operation, low-noise bearingsare usually chosen.
The axial moving
The most common wayto configure bearings is to install a set of shaft-oriented "identicalbearings" at one end of the shaft, and a set of axially movable"movable bearings" at the other end to prevent sticking due to theexpansion and contraction of the shaft. The commonly used "floatingbearing" is the cylindrical roller bearing with inner ring or outer ringwithout baffle. At this time, the matching of inner ring and shaft or thematching of outer ring and outer ring can be adopted. Sometimes, non-separabledeep groove ball bearings or centering roller bearings can be selected asfloating bearings, but clearance fit should be selected for the inner ring andshaft or outer ring and outer hole during installation to ensure that the innerring or outer ring has enough freedom of axial movement.

Friction torque
The frictionresistance of ball bearing is smaller than that of roller bearing. When theaxial load is applied, the friction resistance of the axial contact bearing issmall. When combined load is applied, the friction resistance of bearingcontact Angle is the least. Ball bearings or cylindrical roller bearings aremore suitable for equipment and machinery where low friction torque isrequired. Bearing man WeChat professional! In addition, the low friction torquebearing should avoid using contact seal, at the same time, it is recommended touse drip lubrication, oil and gas lubrication or other lubrication methods thatare conducive to wear reduction.
Installation andremoval
The bearings withcylindrical inner bore are used for mounting and disassembling the machinesfrequently, the separation angular contact ball bearings, taper rollerbearings, detachable cylindrical roller bearings, needle roller bearings andthrust bearings should be preferred. Bearings with conical bore can be mountedon the journal, or on the cylindrical journal by means of a tightener orback-off sleeve.