轴承公差配合（Bearing tolerance fit）
The purpo of the bearing fit is to cure the inner or outer ring of the bearing firmly against the shaft or housing so as to avoid adver axial sliding on the mating surfaces.
spring怎么读
This adver axial sliding (called creep) caus abnormal heat, abrasion of the mating surfaces (which further forces the wear of iron powder into the bearings), and vibration, which prevents the bearings from fully functioning.
Therefore, for bearings, due to load rotation, the rings must generally be weighted to make them firmly fixed to the shaft or housing.stephenchow>六级吧
Dimensional tolerances for shafts and housings
The dimension tolerances of the metric ries of shafts and housings have been standardized by the GB/T275-93 "rolling bearings with shafts and housings", and dimensional tolerances are lected to determine the fit of bearings to shafts or housings.
Matching lection
The choice of cooperation is generally carried out in accordance with the following principles.
The load on each ring can be divided into rotating load, stationary load or non directional load, depending on the load direction, the nature of the bearing and the rotation of the inner and outer rings. Bear the rotating load and non
malarkey
directional load of the ring should be static coordination (interference fit), bear the static load of the ring, it is desirable to transition coordination or dynamic coordination (clearance coordination).
When the bearing is heavy load or vibration or shock load, the interference shall be incread. The u of hollow shafts, thin walled bearing housings or light alloy and plastic bearing housings also increas the amount of interference required.
High precision bearings are required when maintaining high rotation, and dimensional accuracy of shafts and bearing cas can be improved so as to avoid excessive interference. If the interference is too large, the geometry accuracy of the shaft or bearing ca may affect the geometry of the bearing ring, thereby impairing the rotation accuracy of the bearing.
Non parable bearings (such as deep groove ball bearings), both inside and outside the ring with static coordination, the bearing installation and disasmbly is very inconvenient, it is best to u one of the internal and external circle with the coordination.
1) the influence of load properties
Bearing load according to its nature can be divided into inner rotation load, outer rotation load and non directional load, and its relationship with the reference to the bearing matching standards.
2) the influence of load size韩语字母表
The inner ring in the radial load, the radius direction is compresd and stretched for a small increa in the initial perimeter, more interference will be reduced. The amount of interference reduction can be calculated by the lower form:
Here：
Delta dF: inner interference reduction, mm
D: Bearing nominal bore, mm
啄食B: nominal width of inner ring, mm
Fr: radial load, N{kgf}
Co: basic rated static load, N{kgf}
Therefore, when the radial load is heavy load (more than 25% Co), with the ratio of light load must be tight.
If the impact load, the tie must be more tight.
3) the influence of the roughness of the matching surface
If the plastic deformation of the mating faces is considered, the effective interference after matching is approximately expresd by the influence of the processing quality of the mating surface:
[grinding axis]
Delta deff= (d/ (d+2)) * (3)...
iso9001内审员Turning shaft]
street是什么意思Delta deff= (d/ (d+3)) * (4)...
Here：
pasteurizedDelta deff: effective interference, mm
Delta D: apparent interference, mm
D: Bearing nominal bore, mm
4) the influence of temperature
Generally speaking, when the bearing temperature is higher than the peripheral temperature, and when the bearing rotates with the load, the inner ring temperature is higher than the shaft temperature, so the thermal expansion will reduce the effective interference.
The temperature is t up inside the bearing and shell surrounding for t may be assumed to be parabolic inner ring and shaft with the temperature difference approximation for parabolic t (0.01-0.15). So the temperature of the interference of DT can reduce the amount of calculation by type 5 delta:
Delta dt= (0.10 to 0.15) t* alpha Delta *d
About 0.0015 Delta t*d* (5)...
Here：
Delta DT: temperature interference reduction, mm
Delta T: temperature inside and around the bearing shell, C
Alpha: coefficient of linear expansion of bearing steel, (12.5 * 10-6) 1/ DEG C
D: Bearing nominal bore, mm
Therefore, when the bearing temperature is higher than the shaft temperature, the tie must be tight.
In addition, in the outer ring and the shell, due to differences in temperature or coefficient of linear expansion, in turn, sometimes interference will increa. Therefore, it is necessary to pay attention to the thermal expansion of the shaft avoiding the sliding between the outer ring and the mating surface of the shell.
5) meet the maximum internal stress of the bearing
When the bearings are in interference fit, the rings will expand or contract when they are installed so as to produce stress.
When stress is too great, the rings sometimes break and need attention.
cloto
