According to the working accuracy, rigidity, temperature rise and structural complexity of the main shaft components, rolling bearing support is adopted. There are many different configurations. The configuration mode of single-row tapered roller bearing is: the front support adopts double-row tapered roller bearing, which bears radial load and axial load, and the rear support adopts single-row tapered roller bearing,
This configuration can bear heavy load and strong dynamic load, and has good installation and adjustment performance, but the improvement of spindle speed and accuracy is limited. It is suitable for CNC machine tool spindles with medium accuracy, low speed and heavy load.
There are various types of bearings, and the use occasions of various bearings are also different. Tapered roller bearing is a unit composed of tapered raceways (inner and outer rings) and tapered rollers. The structure is suitable for combined loads, such as axial and radial loads acting in two directions. The projection lines of all conical surfaces meet at the same point of the bearing axis to improve rolling and reduce friction. The load capacity can be increased or decreased according to the increase or decrease of contact angle. The larger the contact angle, the higher the load capacity. And they are usually used in pairs to better distribute the radial load. In some overloaded applications, two or four groups can be used together.
In terms of the structure of tapered roller bearings, there are the following characteristics;
(1) They are separable design bearings, that is, the inner race with rolling element forms a unit, which can be installed on the outer race separately.
(2) The axial bearing capacity of the bearing largely depends on the contact angle corresponding to the outer raceway angle.
(3) Tapered roller bearings can bear combined (axial and radial) loads to a large extent, so they have obvious advantages over other bearings.
In addition, tapered roller bearings are widely used in various fields because of their remarkable advantages of bearing axial load and high radial load. Whether the clearance setting of tapered roller bearing is correct or not directly determines the operating life of the bearing, and the setting and adjustment of the clearance is a precise and highly technical project.
Due to the special structure of single-row tapered roller bearing, the clearance of the bearing after installation is not strictly in accordance with the fit with the shaft or bearing seat to reach a certain appropriate value. It is necessary to adjust the axial movement of one raceway relative to the other raceway to achieve the required bearing clearance. The single-row tapered roller bearing will reach a certain internal clearance only after installation, and the clearance value depends on the adjustment of the other bearing used to provide axial positioning in the opposite direction. For single-row tapered roller bearings, there is no standard original radial clearance value provided, and the clearance after bearing installation is controlled by the installer during installation.