What is lining of the equipment?
Misalignment of the compound shaft installed in rolling bearings (availability of the break and/or misalignment of the line of the shaft) in the majority of the mechanisms having the detachable joint in the area of the shaft often is the basic reason of the increased vibrations of the mechanism on rotating speed and its harmonics. The fact that at the same time vibrations and often increase in the axial direction is characteristic.
It is possible to reduce these vibrations only careful lining of the line of the shaft. Experience and knowledge is necessary for lining of the horizontal shaft installed in rolling bearings and having the detachable joint allowing to carry out the joint of shaft with some of their misalignment and/or the break of lines of rotation. Connection type - clutch with rubber-metal joint pins.
When performing centering works it is necessary to have a clear view of absolutely standing task.
It is that it is necessary to scentrovat lines of rotation of two shaft, i.e. not some objects available to touch, observation and measurement, and two certain non-material objects representing, strictly speaking, purely physical concepts - lines around which shaft rotate.
Very often space position of lines of rotation is identified with the space provision of outside surfaces of shaft or semi-couplings that is admissible purely theoretically, in the idealized case when all interfaced parts (shaft, semi-couplings, fingers and so forth) are made and interfaced absolutely ideally. Considering that any mechanism in implementation represents the system of admissions, in all cases it is more reasonable to recognize that ideal mechanisms do not exist. In practice lines of rotation, but in any way not the surfaces of the interfaced bodies have to be centered always. And the machine turns, the nedopustimy substitution by one another are higher.
Researches show that up to 50% of cases of the exit of mechanisms with compound shaft can be out of operation caused by bad lining. In most cases some pliability of the detachable joint of shaft is provided with use of sleeve joint with rubber-metal fingers. It is not necessary to be mistaken concerning functionality of similar connection. The elastic rubber plugs used here for 100% provide the solution only of one task: even badly otcentrovanny shaft (naturally, in limits of elasticity of plugs) after all can be connected and started kinematic.
The additional static loading of the interfaced mechanisms arising at the same time in the radial and axial directions is not compensated in any way. Possibilities of rubber plugs on compensation of dynamic loads in connection also significantly decrease as rubber is the nonlinear compensating element, its rigidity increases with increase in static loading, and, respectively, damping capacity in dynamics decreases.
Thus, low-quality lining leads to development of a number of defects in nodes of the interfaced mechanisms. The static and dynamic loading of bearings increases that leads to the accelerated development of defects. The statistics shows that increase in loading of the bearing for 20% reduces rated durability of the bearing approximately by 50%.
All this occurs against the background of the increasing vibroactivity of the mechanism, and most in low-frequency area of the range (rotating speed and its harmonics), i.e. at those frequencies where levels of vibration create also the greatest dynamic loads on mechanisms. In general the developing situation is aggravated also with the fact that practically all specified phenomena are connected by positive (unfortunately) back coupling.Top