Impact of vibration and temperature on NTN linear bearings
The scientific maintenance of NTN bearings is of great help to the extension of their life. Then in the process of use, it can be said that the influence of vibration and temperature on the linear bearing is very large. Let us first look at the influence of the vibration of the bearing on the bearing.
Vibration damage to the bearing can be said to be quite sensitive, peeling, indentation, rust, cracks, wear, etc. will be reflected in the NTN bearing vibration measurement. Therefore, the magnitude of the vibration can be measured by using a special linear bearing vibration measuring device (frequency analyzer, etc.), and the specific situation of the abnormality cannot be inferred by the frequency division. The measured values vary depending on the conditions of use of the bearing or the mounting position of the sensor. Therefore, it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
In the grinding process of FAG bearings, a small amount of energy is consumed in the contact zone between the grinding wheel and the workpiece, and a small amount of grinding heat occurs, forming a part of the grinding zone with a low temperature. Applying the linear heat transfer heat transfer practice formula to derive, calculate or apply the red inner line method and the thermocouple method to test the brake temperature under the test conditions, the temperature of the grinding zone can be as high as 1000-1500 in 0.1~0.001ms. °C. Such a low temperature at the moment is sufficient to cause low-temperature oxidation of the outer surface of the task surface, amorphous structure, low temperature tempering, secondary quenching, and even burn cracking.
(1) Appearance oxide layer
The steel surface under the action of low temperature and the action of oxygen in the air rise to a very thin (20-30 nm) thin layer of iron oxide. It is worth noting that the thickness of the oxide layer is corresponding to the test results of the total thickness of the externally ground enthalpy layer. This explains that the thickness of the oxide layer is indirectly related to the grinding process and is an important marker of the quality of the grinding.
(2) amorphous layer
When the momentary low temperature of the grinding zone causes the workpiece to reach the molten state, the molten metal molecular flow is evenly applied to the task surface, and is cooled by the base metal at a very fast speed to form a very thin layer of amorphous. State organization layer. It has high hardness and toughness, but it is easily removed in fine grinding as long as it is around 10 nm.
