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 Products New Bearing Technologies |
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| Vibrating Equipment Bearings / Calculation of Load in Bearings and Nominal Life |
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The nominal life for bearings in vibrating equipment is described according to the following factors: machine type, operating hours per year and required reliability, among other considerations. Standard nominal life is approximately 10,000 hours. However, it can range from 4,000 to 15,000 hours.
1. Nominal Life
Where:
Lh: nominal life (hours)
fh: life factor
fw: load coefficient = 1.2
Fr: load on the bearing (N)
Cr: bearing basic load capacity (N)
n: work rotation (rpm)
If the load on the bearing is known, the basic load capacity required is found by using the following equation:
Having calculated the basic load capacity Cr, by using the equation above, select the proper bearing on Table 2.
2. Load on the Bearing
Vibrating screens are rated according to their movement, which can be circular or rectilinear. When a screen weight, vibration amplitude (among other variables) are known, but the load on the bearing is not, it is possible to find it by using the following equation:
Circular Movement Vibrating Screens
Where:
G: screen mass (kg)
G1: eccentric mass (kg)
R: bearing center distance from the eccentric gravity center (m)
r: screen vibration amplitude (m)
fr: load on the bearing (N)
Z: bearing number
n: work rotation (rpm)
Rectilinear Movement Vibrating Screens
At first, the strength components of two rotating eccentrics at the same rotation alternate. When in opposite directions, they annul one another, when in the same direction, they sum one another.
Strength in vibration direction, where strength resultants are minimum, fr min.
Strength in direction perpendicular to vibration direction, where the strength resultants are maximum, fr max.
In this case, with rectilinear movement vibration, the load on the bearings ranges from min fr to max fr. As this process varies sinically, the load on the bearing is expressed by:
fr = 0.68 fr max + 0.32 fr min
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