Page 117 - IGUS Bearing

iglidur M250 iglidur M250
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+80°C +80°C
210MPa 210MPa
Bearing technology | Plain bearings | iglidur M250 Technical data
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Permissible surface speeds Installation tolerances 100.0 0.6
As standard, iglidur M250 is manufactured as a iglidur M250 plain bearings require a relatively large 10.0 0.5
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thick-walled bearing. iglidur M250 is best suited for low amount of bearing clearance for optimal operation. This 0.4
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to medium surface speeds. The maximum permissible ensures that the bearing remains reliable during tempera- 1.0 0.3
surface speed for dry-operating applications is 0.8m/s ture change and water absorption. The disadvantages of 0.2
(rotating) and 2.5 m/s (linear). In practice, though, this the bearings clearance are minimised by the vibration- Surface pressure [MPa] 0.1 Coefficient of friction [µ] 0.1
level is rarely reached due to varying application conditions. dampening properties. The bearings are designed for
Surface speed, page 48 press-fit into a housing machined to a H7 tolerance. After 0.01 0.001 0.01 0.1 1.0 10.0 0.0
being assembled into a nominal size housing, the inner 0 2 4 6 8 10 12 14 16 18 20
Temperature diameter automatically adjusts to the D11 tolerances. For Surface speed [m/s] Load [MPa]
Application temperatures up to +170°C are permissible for particular dimensions the tolerance differs depending on Diagram 01: Permissible pv values for iglidur M250 with a Diagram 05: Coefficient of friction as a function of the
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short periods. However, it is permissible to expose iglidur the wall thickness (please see product range table). The wall thickness of 1mm dry operation against a steel shaft at pressure, v = 0.01m/s
M250 plain bearings to this temperature only if they are shaft should have a recommended minimum h9 tolerance. +20°C, mounted in a steel housing
not subjected to any further load. The maximum long-term Testing methods, page 61
application temperature is +80°C. This is also the point of 50 6
the wear limit, i. e. the temperature over which the wear 5
increases exponentially. For temperatures over +60°C an Chemicals Resistance 40
additional securing is required. Alcohols + up to 0 30 4
Application temperatures, page 53 Diluted acids 0 up to – 20 3 Free cutting steel Cf53, hard chromed 304 stainless steel
Additional securing, page 53 Diluted alkalines + 2 H.a. aluminium HR carbon steel High grade steel
Fuels + 10 Wear [µm/km] 1 Cf53 steel
Friction and wear Greases, oils without additives + Load [MPa] 0 0
The coefficient of friction μ of a plain bearing among other Hydrocarbons + 20 30 40 50 60 70 80
factors is influenced by the surface speed and the load Strong acids – Temperature [°C]
(diagrams 04 and 05). Strong alkalines 0 Diagram 02: Maximum recommended surface pressure as a Diagram 06: Wear, rotating with different shaft materials,
Coefficient of friction and surfaces, page 51 All data given at room temperature [+20°C] function of temperature (20MPa at +20°C) pressure, p = 1MPa, v = 0.3m/s
Wear resistance, page 54 Table 02: Chemical resistance
Chemical table, page 1170 30
Shaft materials 25 rotating
oscillating
The friction and wear are also dependent, to a large degree, Rotating Oscillating linear 4 +23°C 20
on the mating partner. If you observe the coefficient of Long-term m/s 0.8 0.6 2.5 3 +60°C
friction, then the ideal shaft surface finish for iglidur M250 Short-term m/s 2.0 1.4 5.0 2 15
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bearings is Ra = 0.6mm. Diagram 06 and 07 display a Table 03: Maximum surface speeds 10
summary of the results of tests with different shaft materials Deformation [%] 1 Wear [µm/km] 5
executed with plain bearings made of iglidur M250. Up Dry Greases Oil Water 0 0
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to loads of 2MPa the shaft material plays a relatively small Coefficient of friction μ 0.18 -0.40 0.09 0.04 0.04 0 5 10 15 20 Cf53 hard 304SS HR carbon
role for rotational movements. Therefore, a suitable shaft Table 04: Coefficient of friction against steel (Ra = 1μm, Load [MPa] chromed steel
material must be considered for higher loads. These are 50HRC) Diagram 03: Deformation under pressure and temperature Diagram 07: Wear for rotating and oscillating applications
hardened shafts, such as Cf53 or hard-chromed. Diagram with different shaft materials, p = 2MPa
07 shows that iglidur M250 is much better suited for Housing Plain bearings Shaft
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rotational motion than for pivoting movements. However, Ø d1 [mm] H7 [mm] D11 [mm] h9 [mm] 0.7
it must be mentioned that pivoting movements often 0-3 +0.000 +0.010 +0.020 +0.080 -0.025 +0.000 0.6
cause high vibrations, which act on the bearing. This is > 3-6 +0.000 +0.012 +0.030 +0.105 -0.030 +0.000 0.5
where iglidur M250 can show off its special dampening > 6-10 +0.000 +0.015 +0.040 +0.130 -0.036 +0.000
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specifications. In our test, these vibrations are excluded > 10-18 +0.000 +0.018 +0.050 +0.160 -0.043 +0.000 Coefficient of friction [µ] 0.4
for clarity so that the comparison between rotation and > 18-30 +0.000 +0.021 +0.065 +0.195 -0.052 +0.000 0.3
pivoting operation is accurate. > 30-50 +0.000 +0.025 +0.080 +0.240 -0.062 +0.000
Shaft materials, page 56 > 50-80 +0.000 +0.030 +0.100 +0.290 -0.074 +0.000 0.2
> 80-120 +0.000 +0.035 +0.120 +0.340 -0.087 +0.000 0.05 0.10 0.15 0.20 0.25 0.30 0.35
> 120-180 +0.000 +0.040 +0.145 +0.395 -0.100 +0.000 Surface speed [m/s]
Table 05: Important tolerances for plain bearings according Diagram 04: Coefficient of friction as a function of the
surface speed, p = 0.75MPa
to ISO 3547-1 after press-fit ASEAN 09/2023 ASEAN 09/2023
114 3D-CAD, finder and service life calculation ... www.igus-asean.com/M250 Lubrication-free made easy ... from stock ... no minimum order quantity 115