The required life time of the bearing 4.3 Grease life table 4.3 The required life time of the seated rolling bearing (reference) Use conditions The necessary life time of the machine, h household appliances, electric tools, agricultural machinery, heavy lifting devices, etc. 4 000 ~ 8 000 Continuous long-term operation of factory motors, general gear devices, etc. 12 000 to 20 0001 days, normal operation for more than 8 hours or continuous long-term operation of 20,000 to 30 000 24 hours continuous operation, failure of power plant equipment, mine drainage equipment, etc. is not allowed . 100 000～200 000 In the above formula, L: grease life, hdm: ball group pitch circle diameter, mmn: bearing speed, min-1PrCr: basic dynamic load rating of the bearing, NT log Lu003d6.10－4.40×10－6dmn －2.50 －0.05 PrCr－(0.021－1.80×10 8dmn) T(D + d) dmu003d2 (D: bearing nominal outer diameter, d: bearing nominal inner diameter) The applicable conditions of formula (4.7) are as follows. 1) Bearing working temperature: T ℃ is suitable for T≤100 (but when T＜50, take Tu003d50) When T＞100, please contact. 2) Bearing speed: dmn is applicable when dmn ≤ 30×104 but d m n ＜ 12.5, when dmnu003d12.5×104 dmn＞30×104 when dmnu003d12.5×104, please contact. 3) Bearing load conditions: applicable to Pr Cr Pr Cr Pr Cr Pr Cr> 0.2, please contact. When ＜0.05, taking u003d0.05 will uselessly prolong the life of rolling bearing with seat, which is certainly not economical. According to the type and use conditions of the machine using the seated rolling bearing, the necessary life of the seated rolling bearing is set. The necessary life of seated rolling bearings used based on experience is shown in Table 4.3. The grease life of ball bearings for seated rolling bearings is affected by the size of the load, the rotation speed of the bearing, and the operating temperature. The grease life of the component ball bearing when used under normal operating conditions can be estimated by the following formula. (1) Bearing load conditions · Pr/Cr u003d 0.05 2) Bearing load conditions · u003d 0.125 Pr speed · dmn value (×104) (2) Bearing load conditions · u003d 0.2 PrCr Cr speed · dmn value (×10/4) The relationship between the grease life and the bearing's operating temperature, speed and load conditions (reference).