This NSK bearing type has a contact angle, so it is suitable for bearing axial loads in one direction, or combined loads. Structurally, an axial component force is generated when a radial load is applied, so use two or more bearings opposite each other. Single row angular contact ball bearings can use a preload method to increase rigidity, so they are suitable for machine tool spindles with high rotational accuracy (see page A241). In general, angular contact ball bearing cages with contact angles of 30 (code A) and 40 (code B), according to table 1. However, synthetic resin cages or polyamide molded cages are also used depending on the conditions of use. The basic load ratings listed in the dimension table are based on the cage division in Table 1. In addition, the same bearing model has different cage structures and the number of balls also changes, so the rated load is also different from the value described in the dimension table. Angular contact ball bearings with a contact angle of 15 (code C) and 25 (code A5) are mainly suitable for high-precision or high-speed rotation, using copper alloy or synthetic resin cage or polyamide molding cage. The normal maximum operating temperature for polyamide shaped cages is 120°C. Generally, large bearings use a copper alloy machined cage, which has an inner ring guide cage (Figure 2.1) and a rolling element guide cage (Figure 2.2). The contact angles of angular contact ball bearings are different. Even when the same load is applied, the load state of the contact part between the ball and the inner and outer rings is different, and the amount of elastic deformation or the stress of the contact part is also different. As shown in FIG. 3 , the relative load states of the rolling elements at contact angles of 15 and 30 are used to illustrate. The relationship between the axial load and the rolling element load on the bearing is rolling element load u003d Fa/(ball number sin), so the larger the contact angle, the smaller the rolling element load, the smaller the load on the contact part, and the smaller the displacement due to the load. reduced, the life of the bearing is extended. Conversely, when a radial load is applied, the smaller the contact angle, the smaller the rolling element load, and the smaller the load on the contact portion.