In order to compare the load acting on the non rotating bearing with the rated static load, it is necessary to determine the equivalent static load of the bearing, which is a pure radial or pure axial load (whichever is applicable), and the total water age deformation generated at the maximum contact load is the same as that generated by the actual combined load. The theoretical calculation of equivalent static load can be carried out according to the method introduced in Chapter 7. In the case of less strict, for bearings bearing combined radial and axial loads, the equivalent static load can be calculated as follows: F = XF. + YF (9.15) in formula (9.15), if f is greater than f, then f, = f,. Table 9.3 is excerpted from literature [5], which gives the values of X, y, of deep groove ball bearing. The data in table 9.3 is applicable to the bearing with groove curvature not greater than 53% of the ball diameter. Double row bearings are assumed to be symmetrical. The angular contact ball bearing installed face to face or back to back is similar to the double row bearing. Series mounted bearings are similar to single row bearings. For radial roller bearings, the values in table 9.4 can be used, which is extracted from literature [6]. For thrust bearing, the equivalent static load is f = F + 2.3f Tana (9.16). When f, exceeds 0.44f, COTA, the accuracy of formula (9.16) will be reduced. Theoretical calculation shall be carried out according to the method in Chapter 7. Table 9.3 x, y and value of deep groove ball bearing note: 1. F, always ≥ F,. 2. For the contact angle not in the table, y is calculated by linear interpolation. 3. The allowable maximum value of F, / C, depends on the bearing design (groove depth and internal clearance). Table 9.4 x, y and y of radial roller bearing, single row bearing 2 bearing type, double row bearing YXY, self aligning roller and tapered roller bearing a = 0 ° 0.50. 22cota0 The capacity of 44cota ① a = 0 ° sub bearing to bear axial load varies with the design and use of the bearing. Therefore, the bearing user should ask the manufacturer about how to estimate the equivalent load when bearing the axial load at A0 °.

(from: American national standard ansuafbma std9-1990, ball bearing load rating and service life)

It is generally considered that the load for fracture of bearing rolling element or raceway is greater than 8C. See literature [2]. As is known to all, the allowable static load of the bearing is allowed to exceed the rated static load, but the load shall be applied continuously on the rotating bearing. In this way, the permanent deformation will be evenly distributed on the raceway and rolling body, and the bearing can still operate satisfactorily today. On the other hand, if the load is short-term, even if the bearing is rotating at the moment of impact, it will produce even deformation. In this case, it is necessary to select bearings with rated static load exceeding the maximum working load. When the load is used for a long time, the working load can exceed the rated static load without damaging the operation of the bearing. According to the type of bearing application, the safety factor of rated static load can be considered. Therefore, the allowable load is cfs-fs (9.17) 95, and the static load safety factor FS values of various types of work are given. Table 9.5 static load safety factor FS value under working condition, stable operation without impact, 0.5 sudden impact and 22 normal operation have high requirements for stable operation, see example 9.2. 9.7 conclusion for modern ball and roller bearings, the stability of work is an important consideration. If there is damage caused by permanent deformation on the raceway, it will increase friction, noise and vibration. This chapter focuses on the rated static load of the bearing. As long as the bearing is in a static state and does not exceed this load value, significant water induced deformation can be avoided. In the past, the maximum allowable water age deformation was 0.0001d as the basis of the static load rating; later, for various ball and roller bearings, the contact stress limit value corresponding to this deformation was determined respectively. According to this stress value, for each type and size of rolling bearing ground, the calculation method of the basic static load rating is established for the load that not only continuously acts on the bearing but also can obtain satisfactory bearing durability. It is a limit load for a sudden overload or at most a short acting load compared to the normal load on a continuously running bearing. Exceptions to this principle are bearings that do not operate frequently and only for a short period of time. For example, the bearings on the well gate or water gate of the missile. For such applications, bearing design is based on static load rating rather than fatigue life. However, the current static load rating is based on non rotating damage. Because in the case of low rotation speed and infrequent operation, both vibration and surface fatigue are not as important as the excessive plastic flow of materials under the surface. Therefore, the objective of the size selection of such bearings is to eliminate or minimize the above-mentioned plastic flow.