PLANETARY REDUCTION GEARMOTOR VIBRATION DIAGNOSTICS

Transcription

1 ENGINEERING FOR RURAL DEVELOPMENT Jelava, PLANETARY REDUCTION GEARMOTOR VIBRATION DIAGNOSTICS Dmitrijs Ļitvinovs Ria Technical University, Faculty o Transport and Mechanical Enineerin, Institute o Enineerin Technoloy arminius@inbox.lv Abstract. The methods o planetary reduction earmotor vibration dianostics are described in this article. The most requent deects and methods o their estimation usin vibration dianostics are described. The analysis o satellite ear bearins duration work dependin on dierent actors is also resulted. In the end o the paper conclusions are done about appropriateness o planetary reduction earmotor vibration dianostics works conductin. Keywords: requency, envelope spectra, torsion and transversal oscillations, sensor. Introduction A planetary reduction earmotor (Fi. has obvious preerences as compared to an ordinary cylindrical reduction earbox. It is a small speciic material consumption at lare enouh loadin ability that is explained o the hih-capacity earin presence; compactness, noiselessness, less mass and sies, possibility o lare reduction rates obtainin. Fi.. Planetary reduction earmotor Due to the speciic structural constructions, planetary reduction earmotors were and remain the most proressive types o reduction earboxes o industrial application. Compactness, small speciic ravity and, simultaneously, possibility to pass the promoted loadins here what planetary reduction earmotors are attractive or developers and users. Also application o planetary reduction earmotors instead o cylindrical reduction earboxes allows considerably reducin weiht o transmission. Thus, the more power or moment, passed by reduction earmotor, the reater winnin in mass and sies o transmission will et a user. owever in spite o all improvements in the construction o planetary reduction earmotors, it is necessary to practice the permanent monitorin and vibration dianostics o these reduction earmotors. On Fi. the scheme o the simplest planetary earin is resulted. 87

2 ENGINEERING FOR RURAL DEVELOPMENT Jelava, Fi.. The scheme o the simplest planetary earin: a a leadin ear (a sun; satellite; rein; b - epicycle (crown, astened on a case One stae o planetary reduction earbox Fi. consist o leadin ear (a sun a, three intermediate ears (satellites, revolvin on the rein, and bi ear, called by epicycle (crown b. Sometimes or the reduction rate increasin the double satellites (two planes are utilied, each o which are two parallel ears on a shat, which bearins o satellite are set into. Nature o vibration oriin in planetary reduction earmotor There are eneral reularities to the law o acoustic sinal chane character at violations in work o earin mechanism, caused the deects o makin, assemblin and maintenance, bein inormation sources at the estimation o the planetary reduction earmotors technical state. Thus the chanes o vibroacoustic processes develop on a backround o the perturbin orces action, accompanyin normal unctionin o earin and determinin intererences level at dianostics. Noise and vibration o earin arise up as a result o variable orces inluence, conditioned a chane in time o toothin parameters. It means that even the ideal earin can not work noiselessly []. Fi.. Kinematics o planetary reduction earboxes on the basis o one stae planetary earin: a with immobile rein ; b with immobile epicycle (a crown b; c with an immobile leadin ear a (a sun The harmonic constituents o oscillation orces in planetary reduction earboxes have a kinematics and parametritic oriins. Frequencies o oscillation orces are determined by schemes o reduction earboxes Fi. which are very various, especially in the cases, when multi-stae reduction 88

3 ENGINEERING FOR RURAL DEVELOPMENT Jelava, earboxes and earboxes with all rotatin units (a sun, crown, rein are utilied. Gearboxes with sinle satellites can have immobile either crown either rein or a sun. Rotation requencies o earbox ears with immobile rein Fi., a and, accordinly, vibration requencies o basic components accounts also, as well as in usual double stae reduction earbox, that is, rotation requency o satellites is related to rotation requency o a sun []: where ; amount o teeth on a sun and satellite. a, ( Rotation requency o crown is equal accordinly: b a, ( where amount o teeth on a crown. Toothed requency, identical or sun-satellite and satellite-crown earins, is determined by expression: a. ( Rotation requencies rein and satellites in an ideal reduction earbox with an immobile crown Fi. b, in which the number o crown teeth is equal to the sum o a sun teeth number and satellite teeth doubled number, determined as ollows: a, (4 + ( Toothed requency is determined by expressions: b a. (5 ( a. (6 In the real earboxes throuh technoloical reasons at the teeth anular correction the amount o crown teeth is increased on one two, that results in rotation requency o rein small increasin, toothed requencies and satellite rotation requencies. More exactly these requencies can be deined: where + +. a, (7 +, (8, (9 Planetary reduction earboxes with an immobile sun ear Fi. c are utilied much rarer. Rein and crown rotation requencies in such earboxes are determined by correlation: Toothed requency and satellite rotation requency is equal: b. ( + 89

4 ENGINEERING FOR RURAL DEVELOPMENT Jelava, b, ( + b. ( ( + From planetary reduction earboxes with double satellite ears are more requent than other utilied earboxes with one immobile crown, havin either internal or external earin. In irst case a reduction rate comes to the value 5, in the second can exceed. In a earbox with a crown, havin the internal earin, without the account o teeth correction that is under condition: +, ( where ; ; ; number o teeth on a sun ear. Lare and small satellite ears and crown, rotation requency o rein related to rotation requency o sun ear as ollows: a. (4 + + ( ( Rotation requency and toothed requencies o satellite are determined by expressions: ( + +, (5 ( + +, (6 ( + +. (7 In a reduction earbox with a crown, havin the external earin, rotation requency o rein: a. (8 + ( Peculiarities and methods o planetary reduction earboxes vibration dianostics The vibration o planetary reduction earmotors is measured on bearins o input and output shats, and also on a crown (crowns in radial direction. Most diicult or vibration measurin o appear earmotors with the rotatin crown, especially multi-stae, drum execution, in which a vibration can be measured only on rotation supports with one immobile element. In earins with input shat variable direction o rotation the earin vibration stronly depends on direction o its rotation. Thereore the vibration o such earins is measured twice, at each directions o rotation, and the earin vibration state is determined on the vibration maximal sie in any directions o rotation. The toothin o such earin is dianosed also twice, but each periodic operation o dianostics can be conducted at one direction o rotation. Rotatin direction o the dianosed earin in this case chane not on every stae o the dianostic measurin conductin, but durin next operation o dianostics conductin, throuh - month o continuous work. Thus the vibration o earin comparison at dierent times must be made only at the same direction o rotation. The basic eature o planetary earin is the points o orces attack cyclic spatial movin in earin in relation to the immobile vibration sensor, settin on a earbox case, which creates an additional intererence as balanced peak modulation [], showin up in addition two peak-modulated oscillations in opposite phase with complete or partial indemniication o carrier requency. Thus, 9

5 ENGINEERING FOR RURAL DEVELOPMENT Jelava, actual excitation requencies o oscillations in planetary earins do not coincide with requencies, perceived by vibration sensors, related to the immobile coordinate system. In a planetary reduction earbox torsion and transversal oscillations o ears have dierent requency descriptions o distribution ways and subject to dierent mathematical transormations. For torsion oscillations the orm o the sinal transormation is determined by expression (9: U rot. A A A + cos cos( ω t + ϕ [ + A cos( ω t + ϕ ] A A cos( ω t + ϕ + [( ω ω t + ( ϕ ϕ ] + cos[ ( ω + ω t + ( ϕ + ϕ ] For transversal oscillation the transormation orm o initial inormation has the view o balanced modulation with requency ω o perturbation source in space movin in relation to a sensor, set on an immobile case (: U tran. A A { A cos( ω t + ϕ [ + A cos( ω t + ϕ ]} A { cos[ ( ω ω t + ( ω ϕ ] + cos[ ( ω + ω t + ( ω + ϕ ]} + A cos( ω t + ϕ 4 A A A { cos[ ( ω ω ω t + ( ϕ ϕ ϕ t + ( ϕ + ϕ ϕ ] + cos[ ( ω + ω + ω t + ( ϕ + ϕ + ϕ ]} cos[ ( ω ω ω t + ( ϕ ϕ ϕ t + ( ϕ + ϕ ϕ ] + cos[ ( ω + ω + ω t + ( ϕ + ϕ + ϕ ] The important eature o planetary earins vibration is the variable loadins transmission rom one stae to other. As a sie o oscillatin orces in the toothin at least quadratic increases with rotation requency o ears, the slow staes vibration o multi-stae transmissions, mainly, is determined by oscillation orces, passed rom the hih-speed staes. At the same time torques on all staes have near values, thereore, inluencin o identical deects on the dierent staes o reduction earbox results in appearance o comparable on a sie pulsatin moments and comparable on a sie modulation consumed electrical current by the drive electric motor. Exactly rom the listed eatures o oscillatin orces ormin and pulsatin moments in deective reduction earboxes the dianostics o the hih-speed staes o earin is easy to conduct on their vibration, and the low-speed staes on electrical current consumed by a drive electric motor. Analysis o satellite ears rollin bearins operation time dependin on dierent actors On satellite ears rollin bearins operation time the lare inluencin is rendered by such actors as: Manuacturin precision o satellite ears, rein and also epicycle; Reduction earmotor assemblin precision; Presence and quality o reasin; Over loadins durin maintenance. By basic dianostic sinals at state control o the planetary reduction earbox rollin bearins, there is its vibration and temperature. The basic problems o earin bearins dianostics are determined impossibility to measure a hih-requency vibration and temperature o some inaccessible bearins or measurement, and also part o deects dianostic sins coincidence in bearins and in other elements o earin. For rollin bearins deep dianostics the vibration spectral analysis o bearins units, and also spectral analysis o envelope its hih-requency component, are utilied. Thus the coincidence o deect sins o bearins and other units o earin takes a place in those cases, when they are built on vibration harmonic components and random vibration o bearin modulation increasin with requencies, multiple its rotation requency. So, the identical are become reater part o beatin shat sins with the ear (pulley, chain-wheel mounted on it and bearin wear, related to vibration increasin on requencies krot. and vibration modulation by the same requencies. Part o ears distortion sins and heteroeneous radial tihtness o rollin bearin are coincides. The most diicult (9 ( 9

6 ENGINEERING FOR RURAL DEVELOPMENT Jelava, situation arises up rom the coincidence o ear tooth deect sins with the sins o rins slippin in rollin bearin. ow to separate the indicated deects? At irst, at ear deects are oten enouh the electrical current o drive electric motor appears modulated. In the second, practically all deects o ear and earin result in modulation o earin vibration toothed constituent, while the bearins deects such inluencin do not make practically. In the third, the deects ears and earin modulate the hihrequency vibration o most bearins o both earin shats, while bearin deects, as a rule, show up in the imperect bearin vibration envelope spectra only. Conclusions It is possible to make a conclusion comin rom all above-stated that in spite o planetary reduction earmotor labouriousness o vibration dianostics process, especially rollin bearins o satellite ears, application o permanent vibration dianostics and monitorin ives considerable eectiveness o costs due to repairs which are conducted on the equipment actual state. The presence o permanent and operative inormation about the state o reduction earmotors base allows also opportunely plannin the purchase o repair parts, or new reduction earmotors. Also the modern methods o dianostics application allow takin the losses o the inished product and equipment downtime to the minimum, and also allow considerably promotin quality o the inished product. Reerences. Неразрушающий контроль. Справочник в 7 томах под редакцией чл.-корр. РАН В.В. Клюева. Том 7. Машиностроение, Москва, 5. 8 с.. Барков А.В., Баркова Н.А., Азовцев А.Ю. Мониторинг и диагностика роторных машин по вибрации. Санкт-Петербург, Издательство СПбГМТУ,. 6 с.. Генкин М.Д., Соколова А.Г., Виброакустическая диагностика машин и механизмов. Москва: Машиностроение, с. Acknowledements This work has been partly supported by European Social Fund within the National Proramme Support or the carryin out doctoral study proram s and post-doctoral researches project Support or the development o doctoral studies at Ria Technical University. 9