How to select bearings?

Bearing selection can start from the following aspects:

1. Load direction, size and nature

All radial bearings can bear radial loads, and all thrust bearings can bear axial loads. Angular contact ball bearings and tapered roller bearings can be used when bearing radial and axial loads (combined loads) at the same time.

The size of the load is usually determined by the bearing size. Bearings with larger sizes can bear relatively greater loads. Generally, the load carrying capacity of roller bearings is greater than that of ball bearings of the same size. Full complement bearings can withstand heavier loads than corresponding bearings with cages. Therefore, ball bearings are mostly used for medium or smaller loads. In the case of heavy loads and large shaft diameters, roller bearings are generally more suitable.

Angular contact ball bearings and tapered roller bearings need to be installed in pairs.

When the load is not applied to the center of the bearing, an overturning moment will occur. In this case, it is better to use double-row bearings (such as double-row deep groove ball bearings or double-row angular contact ball bearings, etc.). You can also use single-row angular contact ball bearings or tapered roller bearings paired face-to-face or back-to-back. , generally the bearing capacity of back-to-back bearings is higher.

2. Speed

Generally, the operating speed of bearings should be lower than the limit speed listed in the bearing model table. Deep groove ball bearings, angular contact ball bearings and cylindrical roller bearings have higher limit speeds and are suitable for high-speed operation. The thrust bearing limit speed is low.

3. Support limit requirements

Shafts or other components of rotating machinery are usually supported by a fixed end bearing and a floating end bearing. Bearings that can withstand bidirectional axial loads can be used as fixed supports to limit axial displacement in both directions. Bearings that can only bear axial load in one direction can be used as one-way limit supports. The moving support has no position limit. It can choose a radial bearing with an inseparable inner and outer ring to move in the bearing seat hole, or a cylindrical roller bearing with a separable inner and outer ring, in which the inner and outer rings can move relative to each other. .

4. Alignment performance

When the coaxiality of the two bearing housing holes cannot be guaranteed due to various possible reasons or the deflection of the shaft is large, self-aligning ball bearings, spherical roller bearings, and thrust spherical roller bearings with good self-aligning performance should be selected. These bearings It can withstand the angular error caused by the load, and can also compensate for the initial error caused by processing or installation errors, while deep groove ball bearings and cylindrical roller bearings cannot bear any angular error.

5. Stiffness requirements

The stiffness of a rolling bearing refers to the degree of elastic deformation of the bearing under load. This deformation is generally very small and can be ignored. But in some applications, such as machine tool spindle bearings or pinion bearings, stiffness is very important.

Generally, roller bearings have high stiffness, while ball bearings have low stiffness. Angular contact ball bearings and tapered roller bearings use preloading methods to increase the stiffness of the support.

6. Others

Needle roller bearings or needle roller and cage assemblies can be used where the radial space is limited; where there are requirements for bearing vibration and noise, low-noise deep groove ball bearings can be used; bearings that require high rotational accuracy (such as machine tools) Spindle) and used in high-speed working conditions, bearings with higher precision than ordinary grades should be selected.