Scroll Bearing Residual Magnetic Technology Condition
The rolling bearing is the most important part of the modern mechanical basic parts. Its quality directly affects the accuracy of the device, the service life and the stability of the machine. According to statistics, due to the accident caused by the defects of the rolling bearing, the economic loss caused by the running system is over billions of dollars. Magnetic permeability is an important index that reflects the quality of rolling bearings. In order to ensure the high quality of rolling bearings, the magnetic permeability of rolling bearings must reach a certain level. Therefore, residual magnetic technology is widely used in the magnetic permeability test of rolling bearing industry. This article introduces the technical requirements and principles of residual magnetic technology for rolling bearing detection.
Residual magnetic technology is an important means of testing the magnetic permeability of rolling bearings. This technology can measure the magnetic permeability of rolling bearings according to the residual magnetic force in the magnetic field after the rolling bearing receives an alternating magnetic field. The residual magnetic force of the rolling bearing is the output signal of the residual magnetic field sensor. The higher the residual magnetic force, the worse the magnetic permeability of the rolling bearing.
The technical requirements of the residual magnetic technology of the rolling bearing are as follows:
1. The mutual inductor of the test adopts a special mutual inductor and its bias voltage is adjusted to 60V;
2. The spraying liquid of the test adopts 20-micron capillary demagnetizing demagnetizing liquid and its surface tension should not be lower than 23mN/m;
3. The metallic core used for the test should be a deep-seated round steel bar, the magnetic flux of which should reach at least 2000 gauss;
4. The probe used for the test should be a continuous retractable probe and its length should not be shorter than 150mm;
5. The magnetic field of the test should be a homogeneous and uniform magnetic field, and its frequency should not be higher than 200kHz;
6. The test specimen should be placed in the uniform and stable magnetic field, and its rotation speed should not be higher than 200rpm;
7. The time of the rolling bearing test should not be less than eight hours, and the time of the residual magnetic field detection should not be less than five minutes.
The principle of residual magnetic technology of rolling bearing is as follows: when a bearing receives a certain frequency and intensity alternating magnetic field, the distance between the outer ring, inner ring and rolling body of the bearing gradually decreases, while the distance between the rolling body and core metal increases. As a result, part of the magnetic field lines from the metal core will pass through the inner and outer rings of the bearing. At the same time, due to the action of the electro-magnetic effect, the inner and outer rings will generate their own magnetic field, which is superimposed and intertwined with the magnetic field of the test. As a result, a magnetic flux bridge is formed between the inner and outer rings of the rolling bearing. Then by detecting this magnetic flux bridge, the residual magnetic force of the bearing is measured, and the magnetic permeability of the bearing is also judged.
The residual magnetic technology of rolling bearing is a powerful means of magnetic permeability detection. Through combining with the technical standards and specification requirements, defects of the rolling bearing can be detected and avoided, which can effectively improve the quality of rolling bearings, reduce the economic loss caused by malfunction and extend the service life of the device.
