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2 principal parameters are important when using self-lubricating bearings:
1. Shaft gliding speed

Parameters P and VUnder certain conditions these 2 parameters correlate as follows:

P Parameters P and VUnder certain conditions these 2 parameters correlate as follows: X
V The Shafts linear speed in m/sec  = 18 The max. value for oil-steel and bronze

This value can possibly be considerably increased according to the specific conditions:shaft hardness and finish – set-up - runout – extra lubrication

1st ex.
How great is the permitted load for a bearing with Ø int. 20 mm,length 25 mm and shaft speed of 1000 °/m?

Solution:

In the graph under the point graph there is an intersection between thevertical line for 1000 °/m and the curve for Ø 20 shaft and projecting horizontally to the scale at the far left:

P = 18 kp pr. cm2 of the projected surface.

The projected surface is:2 cm (Ø int.) x 2.5 cm (length) = 5 cm2
The max. permitted load on this bearing is:18 kp/cm2 x 5 cm2 = 90 kp

2nd ex.
Determine the necessary length of the bearing given the following conditions: total load 175 kp.
Shaft diameter 20 mm, 500 o/m.

Solution:

In the graph under the point graph there is an intersection between the vertical line for 500 °/m and the curve for Ø 20 shaft and projecting horizontally to the scale at the far left:P = 35 kp/cm2 of the projected surface.

The total load, which is 175 kp, thus requires a projected area of:175 kp: 35 kp/cm2 = 5 cm2 = 500 mm2

Thus the necessary length is:
500 mm2 : 20 mm = 25 mm

NB:
Extremely small or extremely large speeds cannot be extrapolated from the graph.
Consult us for such instances.