Spherical Air Bearings SRA400-R45 / 620-39137

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Able to support 675 pounds of vertical force, this 4 inch radius spherical air bearing will allow rotation of large satellite structures or other payloads without friction. Remarkably, this bearing is supported by a cushion of air only 5 microns in thickness and has a stiffness of nearly 3 million pounds per inch. Pneumatic hammering of the air film can plague an air bearing design and result in unstable bearing performance. Unlike other spherical air bearings, the SRA series eliminates this possibility by including vibration dampening features within the design.

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User Instructions
Comparison Table
Load Capacity, lbs[N] 675 [2970]
Side Load Capacity, lbs[N] 202 [890]
Stiffness, lbs/inch [N/µm] 2793000 [484]
Flow Rate, scfh [slpm] 12.1 [5.7]
Air gap, microinches [µm] 200 [5]
Natural Frequency*, Hz 201
Drag Torque at 30 rpm, oz-in [N-m] 1.42E-02 [1.00E-04]
Physical Properties:
Base Diameter, inches [mm] 7.0 [177.8]
Bearing Height, inches [mm] 6.9 [174.5]
Pedestal Adapter Height, inches [mm] 1.5 [38.1]
Spherical Radius inches [mm] 101.6 [4.0]
Rotational Travel, deg 45
Sphere mounting bolt circle diameter, inches [mm] 4.000 [0.1]
Sphere mounting thread, Unified 3/8-16
Air Supply fitting thread, imperial [metric] M5 [10-32]
Material Aluminum
Assembly Weight, lbs [N] 33.000 [145.2]
Sphere Weight, lbs [N] 16.600 [73.0]
Installation Requirements:
Sphere Mating Surface Required Flatness, inches [µm] .002 [50]
Mating Surface Roughness, microinches [µm] 16 [0.4]
Rated Vacuum, inHg [Mpa] 20 [.06]
Rated Supply Pressure, psig [Mpa] 80 [0.55]
Max. Supply Pressure, psig [Mpa] 100 [0.69]
Air Quality ISO Class 3 or better preferred
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