Considerations on Certain Tribological Aspects of the System Brake Shoe Drum

Size: px

Start display at page:

Download "Considerations on Certain Tribological Aspects of the System Brake Shoe Drum"

Clyde Hoover
5 years ago
Views:

SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN 224-264, Volume 2 No.

he braking process o mining hoising machines. Bellow are presened he componens o he ribosysem, is parameers and he analysis o he uncional parameers or braking process.

1 SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN , Volume 2 No. XXVII Consideraions on Cerain Tribological Aspecs o he Sysem Brake Shoe Drum Mioriţa ngureanu, Vasile Nasui 2 Absrac: The paper presens some consideraions abou he ribological sysem brake shoe-drum in he braking process o mining hoising machines. Bellow are presened he componens o he ribosysem, is parameers and he analysis o he uncional parameers or braking process. Key words: ribological sysem, parameers, braking process. INTRODCTION The brake shoe-drum ribosysem An assembly o elemens inerconneced by srucure and uncion deine a sysem. Czihoş [6], presens in a general manner he ribomechanical sysem. According him is an eniy whose echnical uncions are relaed o he ineracions o he suraces in relaive movemen esablishing is rame conen and main characerisics. The speciic problem o each ribological sysem, especially complex, can be approached sysemically in an uniary orm. [2] The mechanical ribosysems are grouped ino ive caegories: Tribosysems o guiding o movemen; Tribosysems o inormaion ranser; Tribosysems o ransmission o load; Tribosysems o maerial ranspor; Tribosysems o abricaion. The sudy and previous research on ricion processes, aging processes and lubricaion and also on heir implicaions have been conduced on each rybosysem. A rybosysem has he ollowing characerisics (Fig.): Fig.. The general srucure o a ribosysem 8

2 SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN , Volume 2 No. XXVII Elemen, 2,,...,n; Relevan properies o Elemen, 2,,...,n; Speciic relaions beween he elemens o he sysem. 2. THE SHOE-DRM BRAKING TRIBOSYSTEM STRCTRE To deermine he srucure o he brake shoedrum ricion ribosysem we sar orm he general relaions o ribosysems and rom he uncional scheme o he braking sysem ( Fig. ), S { E P R } where: E srucure elemens { E E E E } E 2 (2) i..n, curren number o maerial elemens o he sysem P - relevan properies o he elemen P i { P ( E ) P ( E ) P ( E )} j 2 j 2 n () j..n, curren number o he propery R speciic relaions beween elemens nj n Brake shoe Overall dimensions Type o maerial Relaions beween elemens Inercalae Maerial Abrasive dus Air humidiy Rim brake Overall dimensions Roughness Consrucional ype Fig. 2.The shoe-drum braking ribosysem srucure Enrances [X], exis [Y] a) Enrances X are considered he daes o he braking process, ha is he he process parameers. b) Exis Y are represened by he wear parameers o he shoe and drum, he qualiy parameers o he braking process (eg. he braking duraion), energeical parameers o he process (he ransormaion o braking work in hea). The Funcion o Tribosysem T Fig.. Brake execuion mechanism or hoising machine 2Ţ,5x,7A.[5] In order o reach he aim he sop o he drum he uncion o he sysem is he ransormaion o he enrances ino exis wih he help o a ranser uncion (T). The ranser uncion is he one ha shapes he process by an equaion o he ype: T [ X ] [ Y ] (5) 82

3 SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN , Volume 2 No. XXVII The shaping is locaed on maerial level as well as on energeical and inormaional also[7]. In conclusion, he movemens o he ribosysem elemens are aken ino consideraion, movemens appeared as a sequence o he applicaion o a orce, he ransormaions o he elemens during he process, he inluence o disurbing acors on he process as well as he analysis o he losses. On he basis o he above said we can build he general scheme o he ricion ribosysem, scheme ha hus becomes he sar reerence poin or ulerior using. These will consider he ype o hoising machines, he sae o he sysem a he momen o he braking process (he posiion o he cage, he speed o he sysem).. THE ANALYSIS OF THE FNCTIONAL PARAMETERS THAT INFLENCE THE TRIBOLOGICAL SYSTEM FOR A 2Ţ,5X,7A MACHINE As resuled rom he ribosysem scheme ( Fig. ), or he sudy o he coupling under ribological aspec, he ollowing process parameers are o ineres : The conac pressure beween he shoe and he drum ( or sudying he wear and he deormaions ); The braking work ( or sudying he heaing o coupling elemens).. The Conac Pressure beween he shoe and he drum The disribuion o speciic pressures on ricion suraces beween he shoe and he drum deermines he ype o he wear and inluences is durabiliy [2]. As research [],[] prove, or he brakes where he orce developed by he acioning mechanism is a basic parameer, aer he running, he wearing o he shoes on he lengh levels and esablishes as uniorm, in hese condiions he disribuion o he pressures can be considered consan and uniorm on all he conac lengh. The exernal orces ha ac on he drum and deermine he conac pressures are ( Fig. 4): Fig. 4. The calculaion scheme or conac pressure Normal orce ( reacion) N Fricion orce T T µ N (6) µ - he ricion coeicien beween he she and he rim The conac pressure beween he shoe and he drum is deermined: N p (7) S S- he drum conac surace o a shoe S b l (8) where : b- he widh o he shoe, - he lengh o he shoe. The conac pressure is condiioned by he orces developed by he acioning device. The normal orce in his case is deermined by he realion [8]: G d z N a i (9) where : G - he ransverse elasiciy module o he arch maerial d - he diameer o arch maerial, z - number o he arches in he package ( loor) deormaion o arches in braking posiion c he raio beween he medium diameer o he arches D m and he diameer o he round seel: c D m () d 8

4 SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN , Volume 2 No. XXVII n he number o working coils o he arches; k - coeicien, o end he relaion : k + 2c 2c () For his sysem he ricion orce is : p T 2 G d z µ (2) N p b l G d z i b l a () i 4) Saring orm he equaion (4) we analyse he variaion o he speciic conac pressure o he shoe wih he rim according o he deormaion o he arches ( Fig.5) P i i 47.5 Fig. 5. The conac pressure P i (N/m 2 ) uncion o deormaion o arches i (mm).2 The deerminaion o he braking work In mining here are used dieren ypes o hoising machines, wih dieren ahograms o speed and acceleraion. As a conclusion he deerminaion o an analyical mehod o calculaion o he braking work generally applicable is diicul o realise [4][4]. Expressing he work realised by a shoe over he braking process by he ormula: L M M d ω (5) µ N R (6) The braking momen developed by he wo shoe-brakes applied o he drums is esablished as being he sum o he momens creaed on each shoe, i all our shoes develop he same momen o braking and work simulaneously hen: L M (7) ( ) 4M ( ) where: M - is he momen o ( ) braking developed by a shoe M µ R N (8) ( ) ( ) R- radius drum ( ricion) N ( ) - he resul o normal pressing orces o he shoe onn he drum µ - he ricion coeicien beween he shoe and he drum µ N R ω d µ R N ω (9) As i can be observed by ormula (9) he basic componens on which he braking work depends are: The angular braking speed ω ; The resul o normal pushing orces on he rim N. Bu N - has a variable characer and ω - has a variable characer. As a conclusion, he braking work is a ime uncion and depends on he angular speed o he rim an don he normal orce resuled by pressing he shoe on he drum. 4. CONCLSIONS The paper represens a par o he research on braking sysems on mining hoising machines. On he basis o describing he echnical uncion o he ricion ribosysem shoe-drum we can realise he analysis process or dieren real siuaions (or dieren hoising machines, or dieren ypes o braking, or dieren environmenal condiions). In his paper i has been exempliied he manner o deermining he main uncional parameers ha inluence he ribological sysem or he hoising machine 2Ţ,5x,7A. REFERENCES. Bar L., Banciu M,Marcoş T.,Tudoreanu N.. ş.a., Deerminarea experimenală a orţelor reale de d 84

5 SCIENTIFIC BLLETIN, Serie C, Fascicle: Mechanics, Tribology, Machine Manuacuring Technology ISSN , Volume 2 No. XXVII închidere din sisemul de rânare la maşini de exracţie, CEPROM Sau Mare, Banciu M., Tudoreanu N., Îndrumăor ehnic privind uzura şi oboseala componenelor rânelor maşinilor de exracţie (exemple de calcul) IPROMIN Buzdugan Gh.. - Rezisenţa maerialelor aplicaţii--.. Ediura Academiei Române,Bucureşi Brădeanu, N., Deerminarea domeniului de uilizare a insalaţiilor de exracţie cu unul şi cu mai mule cabluri ; Revisa minelor nr.8/96(pag. 8-22). 5. Coeţiu, R., Pay, G., Coeţiu, A.: Theoreical and experimenal Sudies Abou he Load Variaion Inluence on he Values o Fricion Coeiciens în Rolling Couples Seel Polyamide Maerials. Inernaional Compuer Science Conerence, MicroCAD 2, niversiaea din Miskolc, eb. 2, ISBN , pag Czichos, H., Peersohn, D., Scwarz, W., Oberlächenalas, Technische Oberlachen, Berlin, Czichos, H.,s.a. Hue, Manualul inginerului. Fundamene., Ediura Tehnică, Bucureşi, Maghiari, A., Insalaţii mecanice miniere, Ediura ehnică, Bucureşi, Pavelescu D., Muşa M., Tudor A. Tribologie, Ediura Didacică şi Pedagogică, Bucureşi 977. Popa, A., s. a., Manualul inginerului de mine, vol V, Ediura Tehnică, Bucureşi 989.., ngureanu M., Conribuţii privind sudiul sub aspec ribologic al insalaţiilor de exracţie miniere, Reerade docora2,baia Mare ngureanu N.., Conribuţii privind unele aspece ribologice şi de iabiliae apărue în uncţionarea sculelor miniere de perorare, Teză de docora niversiaea Tehnică Cluj Napoca, 2. * * * Braking or he World s larges mine, World mining equipmen, june * * *Hoiss Advance wih Tehnology, Engineering & Mining Journal, aprilie * * * Maşina podbemnaia şahnaia 2Ţ,5X,7A Tehnicescoe opisanie.. Auhor address: Mioria ngureanu, PhD, eng., Associae Proessor; Faculy o Engineering, Norh niversiy Cener o Baia Mare, Technical niversiy o Cluj Napoca Romania, 48, Baia Mare, Romania, sr. Dr. V. Babes, nr 62/A, m_ungureanu@ubm.ro 2 Vasile Nasui, Proessor; Faculy o Engineering, Norh niversiy Cener o Baia Mare, Technical niversiy o Cluj Napoca Romania, 48, Baia Mare, Romania, sr. Dr. V. Babes, nr 62/A, vasile.nasui@ubm.ro Conac person: Mioria ngureanu, PhD, eng., Associae Proessor; Faculy o Engineering, Norh niversiy Cener o Baia Mare, Technical niversiy o Cluj Napoca Romania, 48, Baia Mare, Romania, sr. Dr. V. Babes, nr 62/A, m_ungureanu@ubm.ro 85

MATHEMATICAL MODELING OF THE TRACTOR-GRADER AGRICULTURAL SYSTEM CINEMATIC DURING LAND IMPROVING WORKS

MATHEMATICAL MODELING OF THE TRACTOR-GRADER AGRICULTURAL SYSTEM CINEMATIC DURING LAND IMPROVING WORKS Bullein of he Transilvania Universiy of Braşov Series II: Foresry Wood Indusry Agriculural Food Engineering Vol. 5 (54) No. 1-2012 MATHEMATICA MODEING OF THE TRACTOR-GRADER AGRICUTURA SYSTEM CINEMATIC