71 KB490 KB69 KB199920252006Augustaitis, Vytautas KazimierasIljin, IgorŠešok, Nikolajštevilka:1018 straniletnik:52str. 662-679ISSN:0039-2480COBISSID:9773083URN:URN:NBN:SI:doc-0UMIUUWGenslAssociation of Mechanical Engineers and Technicians of Slovenia et al.Zveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikofsetni tisktiskarski strojivaljiMetoda raziskave nelinearnih upogibov valjev pri rotacijskem ofsetnem tiskarskem stroju| A method for investigating the nonlinear bends of the cylinders of a web offset printing station|The elastic shifts of the plate, blanket and impression cylinders and, initially, the bends of the cylinders that appear during the rotation of the cylinders that are pressed against each other via the thin elastic cloth (blanket) that covers the blanket cylinders (the cylinders are located in suchway that at least one blanket cylinder exists in each pair of cylinders) have a considerable impact on the operation of web offset printing stations. The cylinders are compressed by shifting their bearing assemblies. The method of investigating the mentioned bends of the cylinders and other elastic shiftsas well as the changes of the pressure along the cylinders that are pressed against each other are described. The nonlinear features of the elasticity of the assemblies of the cylinder bearings, the force of gravity and the location of the axes of the rotation of the cylinders with respect to each other are assessed. The problem under discussion is settled as a complex nonlinear static problem, where the required pressures at the edges of the working surfaces of the cylinders that are pressed against each other are provided and the shifts of the assemblies of the cylinder bearings that are required to ensure the said values of the pressures are unknown at the start. On the application of the method to the specified example, it was shown that the bends of the cylinders noticeably impact on the distribution of the pressure along the contact zone of the cylinders in a modern printing press and on the quality of the printsElastični pomiki valjev s plošč, valjev z gumijasto oblogo in tiskovnih valjev ter se posebej upogibov valjev, ki se pojavijo med vrtenjem valjev, pritiskajo drug ob drugega prek tanke elastične gumirane tkanine, ki pokriva valja z gumijasto oblogo (valji so nameščeni tako, da je v vsakem paru valjev vsaj en valj z gumijasto oblogo), močno vplivajo na delovanje rotacijskega ofsetnega tiskarskega stroja. Valji začnejo pritiskati drug ob drugega zaradi pomikanja njihovih ležajnih sklopov. Prispevek opisuje metodo raziskovanja upogibov valjev in drugih elastičnih pomikov, pa tudi sprememb tlaka vzdolž valjev, ki pritiskajo drug ob drugega. Med raziskavo smo ocenili nelinearne značilnosti elastičnosti sklopov ležajev, sile teže in lege osi vrtenja valjev glede na njihove medsebojne vplive. Obravnavani problem smo rešili kot zahteven nelinearni statični problem, pri katerem smo na robovih delovnih površin valjev, ki pritiskajo drug ob drugega, poznali potrebne vrednosti tlaka, pri tem pa so bili pomiki sklopov ležajev, ki so potrebni za nastanek omenjenih vrednosti tlaka, na začetku neznani. Z uporabo metode na specifičnem primeru smo pokazali, da so upogibi valjev bistveno vplivali na porazdelitev tlaka vzdolž dotikalnega predela valjev sodobnega tiskarskega stroja in s tem tudi na kakovost tiskaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo