iglidur® J260 - material data

Figure 2.2: Maximum recommended surface pressure dependent on the temperature (40 MPa at 20°C)

Figure 2.3: Deformation under load and temperatures

Mechanical properties

Maximum recommended surface pressure represents a mechanical material parameter. Tribological conclusions cannot be drawn from it. With increasing temperatures, the compressive strength of iglidur® J260 plain bearings decreases. Fig. 02 clarifies this connection.

Figure 2.3 shows the elastic deformation of iglidur® J260 with radial loads. Under the maximum recommended surface pressure of 40 MPa, the deformation amounts to less than 2,5%. A potential plastic deformation depends, among other things, on the length of exposure.

m/s	Rotary	oscillating	Linear
Constant	1	0,7	8
Short-term	2	1,4	4

Table 2.2: Maximum surface speeds

Permitted surface speeds

iglidur® J260 is developed for low to medium surface speeds. The maximum values stated in the Table 2.2 can be attained only with minor pressure loads. At the specified speeds, an increase in temperature up to the long-term permitted value can occur due to friction. In practice these limit values are not always reached.

iglidur® J260	Operating temperature
Lower	- 100 °C
Upper, long-term	+ 120 °C
Upper, short-term	+ 140 °C

Table 2.3: Temperature limits for iglidur® J260

Temperatures

The temperatures prevailing in the bearing system also have an influence on the bearing wear. The wear increases with rising temperatures, and the influence is especially marked from 80°C temperature onwards. An additional securing is recommended at temperatures higher than +80°C.

Figure 2.4: Coefficients of friction dependent on the surface speed, p = 0.75 MPa

Figure 05: Coefficients of friction dependent on the load, v = 0,01 m/s

X = Load [MPa]
Y = Coefficient of friction μ

Friction and wear

Just like the wear resistance, the coefficient of friction µ, friction coefficient in short, also alters with the load. Interestingly the coefficient of friction decreases with increasing load, whereas an increasing surface speed causes a slight rise in the coefficient of friction (Fig. 04 and 05).

Figure 06: Wear, rotating application with different shaft materials, p = 1 MPa, v = 0,3 m/s
 
X = shaft materials
Y = wear [μm/km]
 
A = Aluminum, hard-anodized
B = machining steel
C = Cf53
D = Cf53, hard chrome-plated
E = St37
F = V2A
G = X90

shaft materials

Friction and wear also depend to a high degree on the shaft material. Very smooth shafts increase the coefficient of both friction and wear. A smoothed surface with an average surface finish Ra = 0.8 µm is best suited for iglidur® J260. Fig. 06 shows the results of tests of different shaft materials with plain bearings made of iglidur® J260. In this connection it is important to note that with increasing loads, the recommended hardness of the shaft increases. The "soft" shafts tend rather to wear themselves and thus increase the wear of the entire system, if the loads exceed 2 MPa. The comparison of rotation and swivelling in Figure 07 makes it very clear that iglidur J260 bearings display their strengths especially in the rotating operation.

iglidur® J260	Dry	Grease	Oil	Water
Coefficients of friction μ	0,08–0,15	0,09	0,04	0,04

Table 2.4: Coefficients of friction for iglidur® J260 against steel (Ra = 1 µm, 50 HRC)

Figure 07: Wear in pivoting and rotating applications with Cf53 dependent on the load
 
X = Load [MPa]
Y = Wear [μm/km]
 
A=Rotating
B=Pivoting

Medium	Resistance at 20°C
Alcohols	+ to 0
Hydrocarbons	+
Fats, oils, without additives	0 to –
Fuels	–
Diluted acids	–
Strong acids	–
Diluted bases	+ to 0
Strong bases	+ to 0

Table 2.4: Coefficients of friction for iglidur® J260 against steel (Ra = 1 µm, 50 HRC)

Specific forward resistance	> 1012 Ωcm
Surface resistance	> 1010 Ω

Table 2.6: Electrical properties of iglidur® J260

chemical resistance

iglidur® J260 plain bearings are resistant to diluted alkalis, hydrocarbons and alcohols. The extremely low humidity absorption also allows them to be used in wet or humid environment. The humidity absorption of iglidur® J260 bearings amounts to about 0.2% in standard climatic conditions. The saturation limit in water is 0,4%. These values are so low that a consideration of the expansion due to moisture absorption can be neglected.

Radioactive rays

Resistant up to a radiation intensity of 3x 10² Gy

UV-resistant

Partly resistant against UV rays

Vacuum

For application in vacuum, the potentially existent moisture content is degassed. For this reason only the dry iglidur® J260 bearings are suitable for vacuum.

Electrical properties

iglidur® J260 bearings are electrically insulating.

humidity absorption / moisture absorption

The humidity absorption of iglidur® J260 bearings amounts to about 0.2 % in standard climatic conditions. The saturation limit in water is 0.4 %. These values are so low that a consideration of the expansion due to moisture absorption can be neglected.

Diagram 10: Effect of moisture absorption
 
X = Moisture absorption [weight %]
Y = Reduction of inside diameter [%]

Maximum moisture absorption
by +23 °C/50 % r. F.	0,2 Wt.-%
Max. water absorption	0,4 Wt.-%

Table 06: Moisture absorption

Diameter d1 [mm]	Shaft h9 [mm]	iglidur® J260 E10 [mm]	Housing H7 [mm]
Up to 3	0 - 0,025	+0,014 +0,054	0 +0,010
> 3 to 6	0 - 0,030	+0,020 +0,068	0 +0,012
> 6 to 10	0 - 0,036	+0,025 +0,083	0 +0,015
> 10 to 18	0 - 0,043	+0,032 +0,102	0 +0,018
> 18 to 30	0 - 0,052	+0,040 +0,124	0 +0,021
> 30 to 50	0 - 0,062	+0,050 +0,150	0 +0,025
> 50 to 80	0 - 0,074	+0,060 +0,180	0 +0,030
> 80 to 120	0 - 0,087	+0,072 +0,212	0 +0,035
> 120 to 180	0 - 0,100	+0,085 +0,245	0 +0,040

Table 07: Important tolerances iaw. ISO 3547-1 after press-fitting.

Installation tolerances

iglidur® J260 bearings are standard bearings for shafts with h-tolerance (recommended minimum h9). The bearings are designed for press-fit in a housing with h7 tolerance. After the installation in a housing with nominal diameter, the inner diameter of the bearing automatically adjusts to the E10 tolerance. In certain dimensions the tolerance in dependence on the wall thickness deviates from this (See delivery program )