Bearing is an important part of modern mechanical equipment, its main function is to support the mechanical rotating body, reduce its friction coefficient in the process of movement, and ensure its rotation accuracy.
Now, let’s introduce what we should pay attention to when buying bearings?
1. The size, direction and nature of the load of the load bearing [the load of the bearing can be indicated by the basic rated load, and its value is shown in the bearing scale table] the load of the bearing varies greatly, such as the size of the load, whether there is only radial load, whether the axial load is unidirectional or bidirectional, the degree of oscillation or impact, etc. After considering these factors, we can choose the most suitable bearing type.
Generally speaking, the radial load of bearings with the same inner diameter can be increased in the following order: deep groove ball bearing < angular touch ball bearing < cylindrical roller bearing < tapered roller bearing < self-aligning roller bearing
2. Analysis of the relative skewness between the inner ring and the outer ring of the bearing the factors that cause the relative skewness between the inner ring and the outer ring of the bearing (such as the deflection of the shaft caused by the load, the poor accuracy of the shaft and the shell or the device error), and select the type of bearing that can be used to this kind of operating conditions. If the relative skewness between the inner ring and the outer ring is too large, the bearing will be damaged due to the internal load generated by the self-lubricating bearing. Therefore, the bearing type that can accept this skew should be selected.
Generally speaking, the skew angle (or centering angle) is allowed to be added in the following order:
Cylindrical roller bearing, tapered roller bearing, deep groove ball bearing (angular touch ball bearing) and self-aligning roller (ball) bearing 3) the rigidity function meets the rigidity requirement of mechanical shafting [when the bearing accepts the load, the touch part of the rolling body and raceway will have elastic deformation. “High rigidity” refers to the small deformation of this kind of elastic deformation. In the main shaft of machine tool and the final reducer of car, it is necessary to improve the rigidity of bearing while improving the rigidity of shaft.
The deformation of roller bearing under load is smaller than that of ball bearing. Preloading the bearing (negative clearance) improves rigidity. This method is suitable for angular touch ball bearings and tapered roller bearings.
3. For the bearing type whose bearing space can be contained in the bearing space, the shaft diameter, i.e. the inner diameter of the bearing, is generally determined first because the rigidity and strength of the shaft are emphasized in the design of the shaft system. But the rolling bearing has many kinds of scale series and types, so the most suitable type should be selected.
Generally use the following bearings: deep groove ball bearing, touch ball bearing, cylindrical roller bearing
4. Rotation accuracy the type of bearing with required rotation accuracy [the dimension accuracy and rotation accuracy of bearing have been standardized by GB according to the type of bearing? The separation of machine tool spindle, gas turbine and control machine requires high rotation accuracy, high speed and low conflict. In this case, the bearing with accuracy above level 5 should be used.
5. It is convenient to use cylindrical roller bearing, needle roller bearing and tapered roller bearing with separable inner ring and outer ring when assembling and disassembling frequently.
6. The type of bearing whose rotational speed can be used to the mechanical rotational speed [the reference of the limit value of bearing rotational speed is indicated by the limit rotational speed, and its value is listed in the bearing scale table] the limit rotational speed of the bearing is not only taken from the bearing type, but also limited to the bearing scale, cage type, accuracy grade, load condition and smoothing method, etc. Therefore, it is necessary to consider these factors when selecting.
