- 01.03.2016 09:50
- EPK wheel hub bearings are tested for new standards
Bearing 256508ЕК with ABS are currently passing the testing stage for endurance limit. Endurance limit is tested by the main characteristics (performance factors), which measure its resource:
- Metallographical analysis of the material quality and heat treatment;
- Hardness control of rings and rolling elements;
- Fracture load control of rolling elements;
- Dimension control of rolling elements;
- End clearance control of assembled bearing;
- Control of noise and vibration level;
- Control of rotation moment resistant;
- Control of geometric dimensions of bearing details (outer and inner diameters, ring width, runout, etc.);
- Control of profile, roughness, undulation and deviation from roundness of the surface;
Fatigue – is a process of damage accumulation and destruction of the surface layers of race rings and rolling elements. Factors that cause fatigue: temperature, type of a lubricant, load intensity, rotation frequency. Tiniest (micro) damages of a bearing element surface enlarge under the influence of those factors during exploitation process, that prevent smooth rotation and eventually leads to destruction of the bearing.
The task of the tests – is to evaluate performance of a bearing (the surface has no fatigue damages) under the influence of stress conditions that arise during exploitation.
According to the test procedure of the wheel hub bearings that is used at OAO “EPK Volzhsky” the service life tests are conducted under conditions that imitate/simulate turning movement of a vehicle.
The key point of the new life service testing method (fatigue limit) is to imitate (simulate) movements of a vehicle in a straight line, right and left turns in a certain consequence. Bearing passes the cycles of normal and random (increased) loads and should work without interruptions certain amount of time.
After the resource test (life service test) bearings should pass mud salt tests (“Fatigue test in mud conditions”). These tests help to esteem/assess the reliability of the seal to protect the internal work surface from the contamination.
It was stated by Alexander Kopetsky, General Director of OAO “UK EPK” that test such conditions were deliberately overstated and can not be experienced in real-world conditions. However, automobile standards will be tightened. New testing methods have to be accepted and complied if we want to work on innovative markets.