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The second example of calculation for various applications of seated bearings

by:JNSN     2021-12-27
Example 4 Calculation of bearing life Under the conditions of Example 3, calculate the bearing life L10h when used in a blower with a speed of nu003d1000 min-1. ① Take the load factor f w u003d 1.2 from Table 5.1 and calculate the bearing load P r. Pru0026#1048576;u003du0026#1048576;·Fu0026#1048576;u0026#1048576;1.2 ×u0026#1048576;2.27u003d2.72(KN). ② Use UCP306J (bearing UC306) radial dynamic load rating C r u003d 26.7 kN, formula (4.2) to calculate the bearing life L10h. L10hu0026#1048576;u003du0026#1048576;·u0026#1048576;u003du0026#1048576;×10660nCr Pr3 106 60×1 000 26.7 2.72 3≈u0026#1048576;15 800u0026#1048576;(h). ③ Using the calculation chart in Figure 4.1, calculate the bearing life L10h. The speed coefficient for rotation speed nu003d1000 min-1 is f nu003d0.32. Therefore, the life factor f h is calculated based on the speed factor f n, the radial dynamic load rating Cr of the bearing, and the bearing load Pr. Life factor u003du0026#1048576;·u0026#1048576; u003d0.32 ×u0026#1048576; CrPr 26.7 2.72 u003d3.14 According to the life factor f h, the bearing life L10h≈16 000 hours. Example 5 When selecting a rolling bearing with seat and operating under the conditions of shaft speed nu003d1 500 min-1 and radial load Fru003d5 kN, select flange type components (UCF) with a life of at least 2 years (5,000 hours) . However, the radial load Fr is a value including the load factor and gear factor. ① Using the calculation chart in Figure 4.1, obtain the life coefficient f h≈2.16 for the life time Lhu003d5000 h. The speed coefficient for rotating speed nu003d1 500 min-1 is f n≈0.28. Rated dynamic load Cr u003d Fr· u003du0026#1048576;5 ×u0026#1048576;2.16 0.28≈u0026#1048576;38.6(KN). ② From the dimension table, find the flange type component that meets the radial dynamic load rating Cru003d38.6 kN. Diameter series 2, UCF211J (rated dynamic load Cru003d43.4 kN) can be selected. Example 6 When selecting a vertical seat bearing for low-speed rotation and operating under the conditions of radial load Fru003d12 kN and a rotation speed of 8 min-1, select a vertical seat bearing (UCP) with a life of 10 000 hours for a trolley ). ① Use equations (4.4) and (4.5) to calculate the necessary radial dynamic load rating Cr. The speed factor is fnu003du003d(0.03n -1/pu003d(0.03 × 8)-1/3u0026#1048576;≈1.61. The life factor fhu003d≈L10h 2.71 Take the safety factor fsu003d2 from Table 5.6, and calculate the necessary Radial static load rating C0r. C0r=·Pr =u0026#1048576;2 ×u0026#1048576;12 =24(KN). ③It can be judged that there are vibrations and shocks in the work from the use of trolley, so choose heavy load UCP308J (Cru003d40.7 kN, C0ru003d24.0 kN). Example 7 Calculation of bearing life when used at high temperature. Heat-resistant vertical seat bearing (UCP215JD1K2) at a temperature of 175°C, radial load Fru003d4 kN, When operating at speed nu003d800 min-1, calculate the life of the bearing. However, the radial load Fr is a value including the load factor and gear factor. ① Check Table 4.1, calculate the bearing life when used at 175℃ Radial dynamic load rating Cr. Cru0026#1048576;u003du0026#1048576;67.4 × 0.95 = 64.0 (KN) Use formula (4.2) to calculate bearing life L10h. ② When the bearing with housing is operated under the condition of 175℃, the lubricating grease Deterioration is fast, so it cannot be used in the non-lubricating mode. Grease should be refilled at the interval specified in Table 14.4. ③ In addition, when the shaft elongation is relatively large, a seated bearing on the same shaft should be used as the fixed end ( Positioning of the shaft), and the rest of the seated bearing is installed as a free end (refer to the design of the 9-axis and base). Example 8 Calculation of the grease life of the vertical seat bearing UCP204J (bearing UC204) in the radial load Fru003d1kN 、Calculate the grease life when operating at speed nu003d800 min-1. However, the radial load Fr is a value including the load factor and belt factor, and the bearing's operating temperature is 40°C. Use formula (4.7) to calculate lubrication Grease life L. log Lu0026#1048576;u003d 6.10-4.40×10-6 dmn-2.50 -0.05 Pr C-0.021-1.80×10-8 dmn T =6.10-4.40×10-6 ×12.5×104 -2.50 -0.05 u0026#1048576;1 12.8- 0.021-1.80×10-8×12.5×104×50=4.542L≈34 800(h). Example 9 The calculation of the life of the seated bearing when used without oil supply is calculated under the conditions of Example 8. The life of the seated bearing when operating in the non-lubricating mode. ① Calculate the rated life L10h of the bearing using equation (4.2). ② The grease life L of Example 8 is compared with the rated life Lh of the bearing, and the grease life L is shorter. Therefore, the life of the seated bearing is grease life Lu003d34,800 hours.
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