 Due to the use of the composite materials, the maintenance free bearings have good sliding performance and law friction coefficient, high life time and practically no wear of the sliding bearing surface, high chemical durability and appropriateness for the rotation as well as for the oscillation movement.The maintenance free bearings are used in the hydraulic pumps and motors, hydraulic actuators and shock absorbers, electric motors and gears as well as in many other units of the different machines and mechanisms.
Metal-polytetrafluoroethylene composite (metal-fluoroplastic)
Microstructure
| Structure |
Thickness, mm |
Material |
 |
 |
0,010…0,030 |
Polytetrafluoroethylene (PTFE) |
 |
0,200…0,300 |
Sintered bronze |
 |
0,400…2,300 |
Low-Carbon steel padding |
 |
0,005…0,008 |
Protective coating (tin or copper) |
Metal-polytetrafluoroethylene is the best material for the dry friction, though it can also be used with the additional lubrication.
Physical properties
| Parameter |
Measurement unit |
Value |
| Sliding velocity V, max. |
m/s |
2,50 |
| Combined factor pV, max. |
N/mm²×m/s (MPa×m/s) |
1,80 |
| Friction coefficient f |
|
0,02…0,25 |
| Static load Ps, max |
N/mm² (MPа) |
250 |
| Dynamic load Pd, max. |
N/mm² (MPа) |
140 |
| Working temperature range T |
°C |
−200…+280 |
| Shaft surface roughness Ra, max. |
mm |
0,04 |
| Shaft surface hardeness, min. |
HB |
200 |
Metal-polyoxymethylene composite
Microstructure
| Structure |
Thickness, mm |
Material |
 |
 |
0,300…0,500 |
Polyoxymethylene (POM) |
|
0,200…0,300 |
Sintered bronze |
|
0,400…2,200 |
Low-Carbon steel padding |
 |
0,005…0,008 |
Protective coating (tin or copper) |
In comparison with metal-polytetrafluoroethylene, metal-polyoxymethylene has lubrication pockets on the working surface, but it still shows good characteristics even with the minimum lubrication quantity. Due to the augmented polymer coat metal-polyoxymethylene is much less critical to the quality of the sliding bearing surface treatment.
Physical properties | Parameter |
Measurement unit |
Value |
| Sliding velocity V, max. |
m/s |
2,50 |
| Combined factor pV, max. |
N/mm²×m/s (MPa×m/s) |
2,80 |
| Friction coefficient f |
|
0,06…0,12 |
| Static load Ps, max |
N/mm² (MPа) |
140 |
| Dynamic load Pd, max. |
N/mm² (MPа) |
70 |
| Working temperature range T |
°C |
−40…+130 |
| Shaft surface roughness Ra, max. |
mm |
0,04 |
| Shaft surface hardeness, min. |
HB |
200 |
We offer a wide range of the maintenance free bearings from the mentioned above materials of the standard dimension types according to ГОСТ 28773-90 “Plain bearings. Wrapped bushes with anti-friction layer based on polytetrafluoroethylene-KU. Dimensions and tolerances” and ГОСТ 28774-90 “Plain bearings. Wrapped bushes with anti-friction layer based on polyacetal-KX. Types, dimensions and tolerances” as well as of the special dimension types produced according to the customer’s design.
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