and the needs of micro machining in photoelectric industry, the speed of ultra-high speed aerostatic bearing has exceeded 3 x 10e6 DN, which is equivalent to the surface speed of shaft exceeding 150m / s. However, Combined Rolling Bearing since the clearance range of the bearing is between 5-20um, at such a speed, the air film must have the ability to withstand ultra-high shear rate.
The resulting viscous force has a fatal impact on the thermal and dynamic characteristics of the bearing. The newly designed combined rolling aviation bearing with groove overcomes this series of problems. This new design improves the Combined Rolling Bearing high-speed operation, which may increase the speed limit and hardness and reduce the temperature during operation.
overcomes the main limiting factors and makes the aerostatic bearing achieve faster speed. Combining the principles of aerodynamics and statics, the combined rolling bearings with grooves – roller neck bearing with spiral groove and thrust bearing with spiral groove can squeeze the air to the center when the bearing rotates. At high speed, this effect of groove can change the distribution of air pressure in the bearing to a great extent, and improve the load capacity and hardness. The spiral groove can also change the velocity and gradient of the air film in the bearing and reduce the viscous wear of the bearing.
Because the viscous wear of aviation bearing is directly proportional to the area and inversely proportional Combined Rolling Bearing to the gap, the friction of grooved combined rolling bearing is smaller than that of traditional bearing under the same small gap. The higher the speed, the more obvious this advantage. This can be explained by the performance difference between the grooved combined rolling bearing and the traditional aviation bearing..
With the increase of speed and shaft, the small clearance of bearing decreases from 28 um to 16 um. At low speeds, the results are similar to conventional bearings. However, Combined Rolling Bearing when the speed is up to 120000 rev / min, the grooved bearing has obvious advantages, and it is possible to achieve higher speed.
the grooved combined rolling thrust bearing has the same static hardness as the traditional thrust bearing. However, due to the function of the slot, it consumes less energy. In addition, due to the influence of aerodynamic force, the hardness increases with the increase of speed. Combined Rolling Bearing However, the traditional thrust bearing does not have this function.
The advantage of the grooved combined rolling bearing has long been proved by the use of the rotating body of the inner hole grinding mandrel. It is proved that compared with the traditional aviation bearing, the combined rolling bearing with groove can increase the rotation speed by 25% and reduce the current consumption by 10%. People will also design the spindle of high-speed micro equipment to reduce the diameter of the machine tool to 50um. Of course, high speed is inseparable from the accuracy of operation and the slow reduction of heat.
of sum frequency and difference frequency. Now we will explain the contents of sum frequency and difference frequency of rolling bearing. A component fault → fault deterioration → knowledge causing it, it is component fault → fault frequency of other components. The addition and subtraction of frequencies will not only produce the fundamental frequency of a fault frequency. When there is a fault, the fault frequency is likely to exist in the form of sidebands of other existing frequencies.
For example, bearing cage fault frequency FTF generally does not appear at the fundamental frequency of about 0.35x ~ 0.45X speed frequency, but the sideband of BSF, bpor and bpir fault frequency, and can even be modulated into a new frequency with other vibration sources.
If there is a single fault on the bearing outer ring or bearing inner ring, there will only be a single bearing outer ring or bearing inner ring fault frequency (bpor or bpir). When there are multiple faults around him, there will be many harmonic frequencies of the bearing outer ring or bearing inner ring fault frequency (bpor or bpir).