When the FYH rolling bearing with seat is used at high temperature, the bearing material structure will change and the hardness will decrease, so that the basic dynamic load rating of the bearing will be lower than that when used at normal temperature. Once the structure of the bearing material changes, it will not recover even if the temperature returns to normal temperature. Therefore, when a rolling bearing with a seat is used above 150°C, the basic dynamic load rating in the bearing dimension table must be corrected for temperature, that is, multiplied by the temperature coefficient in Table 4.1. Table 4.1 Bearing temperature with temperature coefficient, °C 125 150 175 200 250 Temperature coefficient 1 1 0.95 0.9 0.75 Corrected rating life: The basic rating life (L10) expressed by the formula (4.1) is the fatigue life of a bearing with a reliability of 90%, but according to Depending on the application, a high reliability life with a reliability higher than 90% is sometimes required. In addition, the use of special materials can sometimes prolong bearing life, and even differences in service conditions (such as lubrication, etc.) will affect bearing life. The basic rating life taking into account the above factors is called the modified rating life, which can be calculated by formula (4.6). In the above formula, Lna: Corrected rated life, 106 revolutions is the life of 100n% reliability (that is, the damage probability n%) after taking into account factors such as bearing characteristics and operating conditions. L10: Basic rating life, 106 revolutions life with 90% reliability a1: Reliability factor refer to (1) a2: Bearing characteristic factor refer to (2) a3: Service condition factor refer to (3). Reliability coefficient a1 When calculating the revised rated life with reliability not less than 90% (that is, the damage probability is not higher than 10%), select the reliability coefficient a1 according to Table 4.2. Table 4.2 Reliability coefficient a1Lna a190 L10a 195 L5a 0.6296 L4a 0.5397 L3a 0.4498 L2a 0.3399 L1a 0.21 Bearing characteristic coefficient a2 In this case, the basic rating life of the bearing is corrected by the bearing characteristic factor a2. FYH ball bearings with housings use high-quality vacuum deoxidized bearing steel as the standard bearing material, and the test results show that it has a considerable life extension effect. The bearing characteristic coefficient a2u003d1 can be taken for the ball bearing for FYH rolling bearing with block. In addition, when a special material dedicated to prolonging the fatigue life is used, a2>1 may be adopted. Use condition factor a3 When the service conditions (especially proper lubrication) of the bearing have a direct impact on the life, use the factor a3 to correct the basic rating life. When the lubricating conditions are normal, a3u003d1 can be taken, and when the lubricating conditions are particularly good, a3>1 can be taken. But for the following conditions, take a3<1. ① When the kinematic viscosity of the lubricant during operation is low, for ball bearings.................... Less than 13 mm2/s for roller bearings...... Less than 20 mm2/s ② When the rotation speed is extremely low... dmn is less than 10 000 Remarks ) dmn value represents the product of the pitch circle diameter dm of the ball group and the rotational speed n. ③ When impurities are mixed in the lubricant, even if a2a3>1 is used for special materials, if the lubrication conditions are not suitable, a2a3>1 cannot be achieved. Therefore, when a3<1, it is generally considered that a2≤1.