Technical>Basic rating life and basic dynamic load rating
Basic rating life and basic dynamic load rating

The basic dynamic load rating is an expression of the load capacity of a bearing based on a constant load which the bearing can sustain for 1,000,000 revolutions (the basic rating life). For radial bearings this rating applies to pure radial loads. The common measurement is “L10” life, defined as the number of revolutions before metal fatigue first appears on 10% of a large group of like bearings. This is referred to as basic rating life of fatigue life.The relationship between the basic rating life, the basic dynamic load rating and the bearing load is given in following formula:

If the speed is constant, the basic rating life can also be expressed in terms of hours of operation (revolution), and is calculated as shown in the formula below:

The relationship between rotational speed “n” and speed factor as well as the relation between the basic rating life and the life factor is shown as following:

Example 1: What is the rating life in hours of operation (L10h) for deep groove ball bearing 6208 operating at 650 r/min, with a radial load Fr of 3.2 kN?

● Correlation of bearing basic rating life, life factor and speed factor (Ball bearing)

 n fn n fn L10h fh L10h fh 10 12 14 1.49 1.41 1.34 600 700 800 0.382 0.362 0.347 100 120 140 0.585 0.621 0.654 2800 3000 4000 1.78 1.82 2 16 18 20 1.28 1.23 1.19 900 1000 1200 0.333 0.322 0.303 160 180 200 0.684 0.711 0.737 5000 6000 7000 2.15 2.29 2.41 30 40 50 1.04 0.941 0.874 1400 1600 1800 0.288 0.275 0.265 220 240 260 0.761 0.783 0.804 8000 9000 10000 2.52 2.62 2.71 60 70 80 0.822 0.781 0.747 2000 3000 4000 0.255 0.223 0.203 280 300 400 0.824 0.843 0.928 12000 14000 16000 2.88 3.04 3.17 90 100 120 0.718 0.693 0.652 5000 6000 7000 0.188 0.177 0.168 500 600 700 1 1.06 1.12 18000 20000 22000 3.3 3.42 3.53 140 160 180 0.62 0.593 0.57 8000 9000 10000 0.161 0.155 0.149 800 900 1000 1.17 1.22 1.26 24000 26000 28000 3.63 3.73 3.83 200 220 240 0.55 0.533 0.518 12000 14000 16000 0.141 0.134 0.128 1200 1400 1600 1.34 1.41 1.47 30000 40000 50000 3.91 4.31 4.64 260 280 300 0.504 0.492 0.481 18000 20000 30000 0.123 0.119 0.104 1800 2000 2200 1.53 1.59 1.64 60000 70000 80000 4.93 5.19 5.43 400 500 0.437 0.405 40000 50000 0.0941 0.0874 2400 2600 1.69 1.73 90000 100000 5.65 5.85

● Correlation of bearing basic rating life, life factor and speed factor (Roller bearing)

 n fn n fn L10h fh L10h fh 10 12 14 1.44 1.36 1.3 600 700 800 0.42 0.401 0.385 100 120 140 0.617 0.652 0.683 2800 3000 4000 1.68 1.71 1.87 16 18 20 1.25 1.2 1.17 900 1000 1200 0.372 0.36 0.341 160 180 200 0.71 0.736 0.76 5000 6000 7000 2 2.11 2.21 30 40 50 1.03 0.947 0.885 1400 1600 1800 0.326 0.313 0.302 220 240 260 0.782 0.802 0.822 8000 9000 10000 2.3 2.38 2.46 60 70 80 0.838 0.8 0.769 2000 3000 4000 0.293 0.259 0.238 280 300 400 0.84 0.858 0.935 12000 14000 16000 2.59 2.72 2.83 90 100 120 0.742 0.719 0.681 5000 6000 7000 0.222 0.211 0.201 500 600 700 1 1.06 1.11 18000 20000 22000 2.93 3.02 3.11 140 160 180 0.65 0.625 0.603 8000 9000 10000 0.193 0.186 0.181 800 900 1000 1.15 1.19 1.23 24000 26000 28000 3.19 3.27 3.35 200 220 240 0.584 0.568 0.553 12000 14000 16000 0.171 0.163 0.157 1200 1400 1600 1.3 1.36 1.42 30000 40000 50000 3.42 4.72 4.98 260 280 300 0.54 0.528 0.517 18000 20000 30000 0.151 0.147 0.13 1800 2000 2200 1.47 1.52 1.56 60000 70000 80000 4.42 4.4 4.58 400 500 0.475 0.444 40000 50000 0.119 0.111 2400 2600 1.6 1.64 90000 100000 4.75 4.9