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The rolling bearing shakes the simple theory of the tester

30th September 2010 Bearing Technology 0 Comments

First. The rolling bearing shakes the basic principle

The vibration of the rolling bearing is a very complicated random mechanical phenomenon. Up until now, the total bearing shakes the theory and has not set up yet, it is one of the generally acknowledged still unripe bearing basic theories that the bearing shakes the theory. Shake since a kind of quality judges the standard, according to it, can divide the grade for the bearing quality, it is a kind of quality control means in the manufacture process of the bearing to shake. In the field of bearing, the low technology of shaking the bearing with low noise is a hot technology in the world.

Bearing shake theory basic problem solved to want, according to roll line and roll the intersection of body and the intersection of surface and harmonic frequency spectrum of defect, come, confirm whole vibration frequency spectrum of bearing. It is that the line is densified everywhere, specific frequently that the bearing shakes the spectral characteristic some amplitude is obvious, it is determined that the bearing can be got away dish and rolled body corrugation various harmonic making up and single defects while shaking the spectral the same kind of harmonic wave. So, shake the spectral parameter according to the bearing to confirm that it is n-values to cause those vibrant defective questions, it is not nonambiguity, therefore can not solve either.

Cause the vibrant reason of the rolling bearing to be very complicated, a large amount of theoretical research and experimental study show, to it shakes sources to be basically rolling bearing: Roll line and round offsetting and corrugation to roll body; Destroy person who exposed to, lubricate oil film roll line and roll body whom coarse surface interact micro protruding; Impurity particle of pollution; Change of rigidity when the bearing is rotated; Swing while keeping the shelf rotating.

Deep the intersection of ditch and the intersection of ball bearing and scope of application most wide consumption most large, how reduce dark the intersection of ditch and vibration and noise of ball bearing, have a lot of ripe measures. These measures include: Improve and roll round degree of one, corrugation and roughness; Adopt corrugation, roughness and spherical to offset a better one and pass the intersection of surface and steel ball of intensification; Control the internal and external foot-paths well, the internal and external ditch foot-paths, the dimensional tolerance errors of steel ball rule value and bearing backlash; Adopt low and shake the lubricated oil with low noise; Get away different camber radius of ditch and raise the shape of the ditch to offset adopt; Improve and clean degree; Adopting the plastics keeps the shelf; Adopt, wrap hole up shape very round, wrap hole up interval relatively little, board wide size relatively loud to press keeping the shelf; Adopt size and shape of external diameter and add the sealed circle or dust ring controlled severely; Control the superficial knocking against wounded of part strictly.

Second, bearing examine and shake the principle of measurement of the appearance

The inner circle is being rotated with a certain invariable rotational speed when the bearing is being measured, the outer lane is being fixed, the sensor engages the bearing outer lane and follows the outer lane to shake together. The sensor transforms the mechanical signal picked up into the electronic signal and sends to the electronic measuring instrument, after operation is dealt with, the electronic measuring instrument shakes the number value virtual value, peak value Reveal, at gauge outfit, reveal, at the oscillograph, sound shaking the noise out through the loudspeaker shaking wave forming.

The bearing examines and shakes the appearance and is mainly made up of five parts: First, main shaft system, function is to drive the inner circle of bearing to rotate. Second, the radial, with loading the device axially, function is the fixed bearing outer lane, certain urgent strength in advance that and offer. Examine deep the intersection of ditch and ball bearing, need, load axially only, examine cylinder get away sub bearing, need the radial to load. Third, the sensor adjusts the device, function is to make the sensor flexible from head to foot and is moved, the sensor should be in the appropriate position while measuring. Fourth, the sensor, function is to pick up the bearing and shake signals. Fifth, electronic measuring instrument, function is that the operation shakes signals, and with the number value. The ways of wave form and sound reveal.

Third, bearing examine and shake the appearance classification

The bearing examines and shakes the appearance to divide according to the bearing type examined, can be divided into a deep ditch ball bearing and examined and shaken the appearance. The taper rolls the sub bearing examines and shakes the appearance. The axle connects with the bearing and examines and shakes appearance,etc..

Bearing examine shake appearance according to examine, bear the size, divide into, can be divided a miniature bearing into and examined and shaken the appearance, small-scale bearing to examine and shake the appearance, the medium-sized bearing examines and shakes the appearance, the large-scale bearing examines and shakes the appearance. It is low that large-scale to examine and shake the rotational speed large in size of main shaft of the appearance.

Bearing examine shake appearance according to say vibrant physical parameter divide, can divide into acceleration examine, shake appearance and speed examine shake the appearance. The former adopts the speed sensor to pick up the bearing and shake signals, the electronic measuring instrument is divided into three frequency bands; The latter adopts accelerometers, the electronic measuring instrument frequency band is the single frequency band 50Hz-10KHz .

Fourth, bearing examine the basic demand which shakes the appearance

Examine the basic demand which shakes the appearance, summarize a word: The examining value should be accurate, it should be clear to listen to the noise. It must pay attention to the following several respect to accomplish this:

1,The bearing examines and shakes appearance to shake promptly the foundation is shaken low.

2,It is high to turn the precision round the main shaft, it is with low noise to examine, especially the quite bearing one examines shaking the appearance, main shaft turn round precision want, control in the intersection of radial and error of beating for generally <1um,??????<3um,?????????????????????

3,The main shaft rigidity should be big, the main shaft rigidity is good, mean the stability of examining value and the repetitiveness is good.

4,The main shaft rotates flexibly and lightly, can’t block phenomena, the main shaft rotates the good examining and shaking the high resolving power of the appearance of flexibility, the noise sounds clear and lifelike.

5,Axial load and main shaft are turned the centre line co-axle degree round on good termsly, radial load must pass the geometirc centre of a circle of the bearing, guarantee examined the bearing to operate steadily.

6,The electronic measuring instrument resists and does and combs ability better, with the improvement of the bearing quality, it is smaller and smaller to shake signals, especially quite bearing, it is smaller and weaker to shake signals, the interference-free performance of this pair of electron tube instruments has proposed higher requirement.

7,Electronic measuring instrument standard to take correct, person who examine should true, neither partial and big, no the able person, in order to shrink either.

8,A characteristic frequently of the sensor should be smooth within the range of 50Hz to 10KHz.

Fifth, bearing examine the development trend of shaking the appearance

China examines and shakes the appearance to mostly operate manually at present, with testing development and bearing of technology shake the completion of the theory, the future one examines and shakes the appearance to develop towards automation and intelligent direction. Automation refers to the automatic material loading unloading of the bearing, overturn automatically, is some test more automatically. It is not too high to reach to accomplish this point, in fact, the semi-automatic one examines and shakes the appearance to research and develop and succeed and come into operation, but want developed automation to examine and shake the appearance, there are very long waysing will go. It is how to discern the manufacture defect of the bearing automatically that intelligent to examine and shake the basic problem to be solved of the appearance. Cause the bearing to shake and lean towards the large problem on inner circle or outer lane? Roll body or oil? Can discern this automatically such as examining and shaking the appearance, manufacturers of this pair of bearings control quality to be a good news. It’s a pity though a lot of people are exploring this question, up until now, also there is not a successful case in the whole world, the key reason is that the bearing shakes the basic theory and has not improved setting up yet, a great deal of existing bearings all have certain limitation to shake mathematical model. It is analyzed that the characteristic frequency of the bearing contributes to further realizing vibrant essence, when last signal to provide convenience land and frequently signal analytical method of land for studying bearing, come, research and develop intelligent to examine, shake the appearance, at repaying and trying on stage even through them.

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