Investigation of the load and service conditions influence conditions influence on the cardan coupling operational capacity

Generalno posmatrano, svi mašinski sistemi se sastoje od pogonske i radne grupe, odnosno pogonske i radne mašine. Spoj ovih mašina se ostvaruje posebnim sklopovima, mašinskim elementima – spojnicama. Njihova osnovna funkcija je prenošenje opterećenja i kretanja sa pogonske na radnu mašinu. Poznato je da su spojevi najčešće najslabija karika u svakom mašinskom sistemu. Saglasno velikom skupu različitih radnih i pogonskih mašina, sa različitim radnim performansama, razvijen je veliki broj različitih spojnica. Međutim, kod transportnih sredstava i drugih mašina, uslovi rada nalažu različite međusobne položaje pogonske i radne mašine. Ime i pojam posebne vrsta spojnica vezano je za pionire u konstrukciji ovih spojnica, slavnog italijanskog naučnika Đerolama Kardana (Gerolamo Cardano, 1501-1576) i Roberta Huka (Robert Hooke, 1635-1703). Konstrukciona rešenja ovih spojnica prolazila su kroz različite faze razvoja. Dinamika razvoja konstrukcionih rešenja ovih spojnica prikazane je u posebnom Poglavlju 3 ove disertacije. Kardanove spojnice (kardanska vratila) su posebna vrsta mehanizama za prenošenje obrtnog momenta, odnosno snage, koji spajaju vratila čije se ose nalaze prostorno pod izvesnim stalnim ili u toku rada promenljivim uglom, dozvoljavajući, pri tome, u toku vremena relativno pomeranje. Ovo pomeranje može biti ugaono i translatorno. Glavni pokazatelji radne sposobnosti kardanovih spojnica je njihov radni vek i stepen pouzdanosti. Najveći uticaj na ove pokazatelje radne sposobnosti ima karakter raspodele linijskog opterećenja kod spregnutih delova Kardanove spojnice. U cilju rasvetljavanja fenomena raspodele linijskog opterećenja i sagledavanja stepena kompatibilnosti između geometrijskih karakteristika spregnutih delova i raspodela linijskih opterećenja, u disertaciji su formirani analintički i numerički modeli pod odgovarajućim predpostavkama.general, all mechanical systems consist of drive and driven groups, or driving and driven machines. The connection of these machines is achieved by special joints, machine elements - couplings. It is known that these joints are often the weakest link in any mechanical system. Pursuant to a large set of different drive and driven machines with different operating performance, a large number of different coupling types were developed. However, а working conditions of transport vehicles and other machinery require different mutual positions of the driving and operating machinery. The name and concept of one type of couplings is related to the pioneers in the design of these joints, the famous Italian scientist Gerolamo Cardano (1501-1576) and Robert Hooke (1635-1703). The designs of these couplings are passed through various stages of development. The innovative designs development dynamics of these couplings are shown in a separate chapter 3 of this study. Cardan joints (cardan shafts) have a large range of applications in mechanical engineering because of the capability of transferring the load and motion from one shaft to another with different joint angle allowing, thereby, over time relative movement. This movement can be angular and translational. The main indicators of functional ability of cardan coupling are their service life and reliability. The greatest influence on these indicators of functional ability has the character of the linear load distribution on cardan joints rolling parts. In order to shed some more light to the phenomena of linear load distribution and correlation between the geometric characteristics of rolling elements and the distribution of the linear load, analytical and numerical models under appropriate assumptions are established in this study. The obtained results shows, that with the standard (the existing) geometry of rolling parts, the engagement of points in root of Cardan cross jurnal in the load transfer is negligible due to very uneven linear load distribution. This unfavorable distribution of the linear load can be reduced with an appropriate combination of geometrical parameters of cardan cross rolling parts. Greater improvement of linear load distribution, ordering the appropriate shape reconstruction of cardan cross rolling parts

Investigation of the load and service conditions influence conditions influence on the cardan coupling operational capacity

Generalno posmatrano, svi mašinski sistemi se sastoje od pogonske i radne grupe, odnosno pogonske i radne mašine. Spoj ovih mašina se ostvaruje posebnim sklopovima, mašinskim elementima – spojnicama. Njihova osnovna funkcija je prenošenje opterećenja i kretanja sa pogonske na radnu mašinu. Poznato je da su spojevi najčešće najslabija karika u svakom mašinskom sistemu. Saglasno velikom skupu različitih radnih i pogonskih mašina, sa različitim radnim performansama, razvijen je veliki broj različitih spojnica. Međutim, kod transportnih sredstava i drugih mašina, uslovi rada nalažu različite međusobne položaje pogonske i radne mašine. Ime i pojam posebne vrsta spojnica vezano je za pionire u konstrukciji ovih spojnica, slavnog italijanskog naučnika Đerolama Kardana (Gerolamo Cardano, 1501-1576) i Roberta Huka (Robert Hooke, 1635-1703). Konstrukciona rešenja ovih spojnica prolazila su kroz različite faze razvoja. Dinamika razvoja konstrukcionih rešenja ovih spojnica prikazane je u posebnom Poglavlju 3 ove disertacije. Kardanove spojnice (kardanska vratila) su posebna vrsta mehanizama za prenošenje obrtnog momenta, odnosno snage, koji spajaju vratila čije se ose nalaze prostorno pod izvesnim stalnim ili u toku rada promenljivim uglom, dozvoljavajući, pri tome, u toku vremena relativno pomeranje. Ovo pomeranje može biti ugaono i translatorno. Glavni pokazatelji radne sposobnosti kardanovih spojnica je njihov radni vek i stepen pouzdanosti. Najveći uticaj na ove pokazatelje radne sposobnosti ima karakter raspodele linijskog opterećenja kod spregnutih delova Kardanove spojnice. U cilju rasvetljavanja fenomena raspodele linijskog opterećenja i sagledavanja stepena kompatibilnosti između geometrijskih karakteristika spregnutih delova i raspodela linijskih opterećenja, u disertaciji su formirani analintički i numerički modeli pod odgovarajućim predpostavkama.general, all mechanical systems consist of drive and driven groups, or driving and driven machines. The connection of these machines is achieved by special joints, machine elements - couplings. It is known that these joints are often the weakest link in any mechanical system. Pursuant to a large set of different drive and driven machines with different operating performance, a large number of different coupling types were developed. However, а working conditions of transport vehicles and other machinery require different mutual positions of the driving and operating machinery. The name and concept of one type of couplings is related to the pioneers in the design of these joints, the famous Italian scientist Gerolamo Cardano (1501-1576) and Robert Hooke (1635-1703). The designs of these couplings are passed through various stages of development. The innovative designs development dynamics of these couplings are shown in a separate chapter 3 of this study. Cardan joints (cardan shafts) have a large range of applications in mechanical engineering because of the capability of transferring the load and motion from one shaft to another with different joint angle allowing, thereby, over time relative movement. This movement can be angular and translational. The main indicators of functional ability of cardan coupling are their service life and reliability. The greatest influence on these indicators of functional ability has the character of the linear load distribution on cardan joints rolling parts. In order to shed some more light to the phenomena of linear load distribution and correlation between the geometric characteristics of rolling elements and the distribution of the linear load, analytical and numerical models under appropriate assumptions are established in this study. The obtained results shows, that with the standard (the existing) geometry of rolling parts, the engagement of points in root of Cardan cross jurnal in the load transfer is negligible due to very uneven linear load distribution. This unfavorable distribution of the linear load can be reduced with an appropriate combination of geometrical parameters of cardan cross rolling parts. Greater improvement of linear load distribution, ordering the appropriate shape reconstruction of cardan cross rolling parts

Analysis of grease contamination influence on the internal radial clearance of ball bearings by thermographic inspection

One of the most important factors influencing ball bearings service life is its internal radial clearance. However, this parameter is also very complex because it depends on applied radial load and ball bearings dimensions, surface finish, and manufacturing materials. Thermal condition of ball bearings also significantly affects internal radial clearance. Despite many researches performed in order to find out relevant facts about different aspects of ball bearings thermal behaviour, only few of them are dealing with the real working conditions, where high concentration of solid contaminant particles is present. That is why the main goal of research presented in this paper was to establish statistically significant correlation between ball bearings temperatures, their working time, and concentration of contaminant particles in their grease. Because of especially difficult working conditions, the typical conveyor idlers bearings were selected as representative test samples and appropriate solid particles from open pit coal mines were used as artificial contaminants. Applied experimental methodology included thermographic inspection, as well as usage of custom designed test rig for ball bearings service life testing. Finally, by obtained experimental data processing in advanced software, statistically significant mathematical correlation between mentioned bearings characteristics was determined and applied in commonly used internal radial clearance equation. That is the most important contribution of performed research the new equation and methodology for ball bearings internal clearance determination which could be used for eventual improvement of existing bearings service life equations

Investigation of the load and service conditions influence conditions influence on the cardan coupling operational capacity

Генерално посматрано, сви машински системи се састоје од погонске и радне групе, односно погонске и радне машине. Спој ових машина се остварује посебним склоповима, машинским елементима – спојницама. Њихова основна функција је преношење оптерећења и кретања са погонске на радну машину. Познато је да су спојеви најчешће најслабија карика у сваком машинском систему. Сагласно великом скупу различитих радних и погонских машина, са различитим радним перформансама, развијен је велики број различитих спојница. Међутим, код транспортних средстава и других машина, услови рада налажу различите међусобне положаје погонске и радне машине. Име и појам посебне врста спојница везано је за пионире у конструкцији ових спојница, славног италијанског научника Ђеролама Кардана (Gerolamo Cardano, 1501-1576) и Роберта Хука (Robert Hooke, 1635-1703). Конструкциона решења ових спојница пролазила су кроз различите фазе развоја. Динамика развоја конструкционих решења ових спојница приказане је у посебном Поглављу 3 овe дисертације. Карданове спојнице (карданска вратила) су посебна врста механизама за преношење обртног момента, односно снаге, који спајају вратила чије се осе налазе просторно под извесним сталним или у току рада променљивим углом, дозвољавајући, при томе, у току времена релативно померање. Ово померање може бити угаоно и транслаторно. Главни показатељи радне способности карданових спојница је њихов радни век и степен поузданости. Највећи утицај на ове показатеље раднe способности има карактер расподеле линијског оптерећења код спрегнутих делова Карданове спојнице. У циљу расветљавања феномена расподеле линијског оптерећења и сагледавања степена компатибилности између геометријских карактеристика спрегнутих делова и расподела линијских оптерећења, у дисертацији су формирани аналинтички и нумерички модели под одговарајућим предпоставкама.general, all mechanical systems consist of drive and driven groups, or driving and driven machines. The connection of these machines is achieved by special joints, machine elements - couplings. It is known that these joints are often the weakest link in any mechanical system. Pursuant to a large set of different drive and driven machines with different operating performance, a large number of different coupling types were developed. However, а working conditions of transport vehicles and other machinery require different mutual positions of the driving and operating machinery. The name and concept of one type of couplings is related to the pioneers in the design of these joints, the famous Italian scientist Gerolamo Cardano (1501-1576) and Robert Hooke (1635-1703). The designs of these couplings are passed through various stages of development. The innovative designs development dynamics of these couplings are shown in a separate chapter 3 of this study. Cardan joints (cardan shafts) have a large range of applications in mechanical engineering because of the capability of transferring the load and motion from one shaft to another with different joint angle allowing, thereby, over time relative movement. This movement can be angular and translational. The main indicators of functional ability of cardan coupling are their service life and reliability. The greatest influence on these indicators of functional ability has the character of the linear load distribution on cardan joints rolling parts. In order to shed some more light to the phenomena of linear load distribution and correlation between the geometric characteristics of rolling elements and the distribution of the linear load, analytical and numerical models under appropriate assumptions are established in this study. The obtained results shows, that with the standard (the existing) geometry of rolling parts, the engagement of points in root of Cardan cross jurnal in the load transfer is negligible due to very uneven linear load distribution. This unfavorable distribution of the linear load can be reduced with an appropriate combination of geometrical parameters of cardan cross rolling parts. Greater improvement of linear load distribution, ordering the appropriate shape reconstruction of cardan cross rolling parts

Influence of the geometry parameters of cardan joint rolling parts on the load distribution

Kardanove spojnice se široko primenjuju u mašinstvu zbog mogućnosti prenošenja opterećenja i obrtnog kretanja sa jednog vratila na drugo, čije se ose međusobno seku pod promenljivim uglom. Vitalni delovi ovih spojnica imaju ograničeni radni vek zbog nedovoljne površinske čvrstoće kontaktnih površina spregnutih delova. Raspodela opterećenja spregnutih delova Kardanove spojnice ima veliki uticaj na nosivost i njihov radni vek. U tom cilju, u ovom radu, detaljno je analizirana raspodela opterećenja duž linije dodira rukavca Kardanovog krsta i kotrljajnih tela - iglica. Razvijeni su odgovarajući analitički i numerički modeli. Na osnovu razvijenih modela, moguće je izvršiti optimizaciju geometrijskih veličina sa aspekta ravnomernosti raspodele opterećenja spregnutih delova Kardanove spojnice.Cardan joints have a wide range of applications in mechanical engineering because of the capability of transferring the load and motion from one shaft to another with different joint angle. The vital parts of these joints have a limited life due to insufficient surface strength in the area of rolling parts contact. Load distribution of Cardan joints composite parts have a major impact on their capacity and service life. Therefore, a detailed analysis of load distribution along the line of contact between Cardan Cross pins and rolling parts - needles, was carried out in this paper. Appropriate analytical and numerical models are developed. Based on the developed models, it is possible to optimize the geometrical parameters in terms of uniformity of load distribution of Cardan joints component in contact

Influence of the geometry parameters of cardan joint rolling parts on the load distribution

Kardanove spojnice se široko primenjuju u mašinstvu zbog mogućnosti prenošenja opterećenja i obrtnog kretanja sa jednog vratila na drugo, čije se ose međusobno seku pod promenljivim uglom. Vitalni delovi ovih spojnica imaju ograničeni radni vek zbog nedovoljne površinske čvrstoće kontaktnih površina spregnutih delova. Raspodela opterećenja spregnutih delova Kardanove spojnice ima veliki uticaj na nosivost i njihov radni vek. U tom cilju, u ovom radu, detaljno je analizirana raspodela opterećenja duž linije dodira rukavca Kardanovog krsta i kotrljajnih tela - iglica. Razvijeni su odgovarajući analitički i numerički modeli. Na osnovu razvijenih modela, moguće je izvršiti optimizaciju geometrijskih veličina sa aspekta ravnomernosti raspodele opterećenja spregnutih delova Kardanove spojnice.Cardan joints have a wide range of applications in mechanical engineering because of the capability of transferring the load and motion from one shaft to another with different joint angle. The vital parts of these joints have a limited life due to insufficient surface strength in the area of rolling parts contact. Load distribution of Cardan joints composite parts have a major impact on their capacity and service life. Therefore, a detailed analysis of load distribution along the line of contact between Cardan Cross pins and rolling parts - needles, was carried out in this paper. Appropriate analytical and numerical models are developed. Based on the developed models, it is possible to optimize the geometrical parameters in terms of uniformity of load distribution of Cardan joints component in contact

Construction variation of packing machine in food processing

U radu je prikazano varijantno konstrukciono rešenje mašine za pakovanje prehrambenih proizvoda. Na osnovu tehno-ekonomske analize pokazano je da originalno i varijantno konstrukciono rešenje imaju približno istu tehničku vrednost, s tim što varijantna konstrukcija ima veću ekonomsku vrednost opravdanost. Ekonomska opravdanost postignuta je pogodnim konstrukcionim rešenjem i primenom domaćih komponenti i tehnologije izrade.The construction variation of packing machine in food processing is shown in this paper. By the techno-economic analyses it is shown that original and new construction has the same construction value, but the new construction has a better economic value – validity. Better economic value has achieved with new construction and engaging domestic components and production technology

Construction variation of packing machine in food processing

U radu je prikazano varijantno konstrukciono rešenje mašine za pakovanje prehrambenih proizvoda. Na osnovu tehno-ekonomske analize pokazano je da originalno i varijantno konstrukciono rešenje imaju približno istu tehničku vrednost, s tim što varijantna konstrukcija ima veću ekonomsku vrednost opravdanost. Ekonomska opravdanost postignuta je pogodnim konstrukcionim rešenjem i primenom domaćih komponenti i tehnologije izrade.The construction variation of packing machine in food processing is shown in this paper. By the techno-economic analyses it is shown that original and new construction has the same construction value, but the new construction has a better economic value – validity. Better economic value has achieved with new construction and engaging domestic components and production technology

Analysis of the Drive Shaft Fracture of the Conveyor Belt for Transport of Coal

The conveyor belt for slag and coal transport in the open mine pit "Kolubara" - Serbia is driven by means of two drive drums : attached on separate shafts. Each shaft is driven by two electric motors on both sides. During exploitation, the conveyor belt drive shafts are subjected to torques and transverse forces due to belt tension. The gearboxes and the bearing units on both sides of the drive drum support each shaft. A fracture of one of the drive shafts of the conveyor belt occurred at its connection point with the gearbox. The first part of the paper defines the loads relevant for shaft calculation, based on measurements in different phases of operation and the manufacturer's data. It is followed by the FEM analysis and fatigue analysis, for the most unfavourable load case. It has been established that the critical stress value has occurred near the connection point between the shaft and the gearbox, in the fracture zone. The second part of the paper presents chemical composition and mechanical properties of material, as well as metallographic examination of fracture surface. The experimental test procedure shows that the fracture has occurred not because of an error in the material but as a consequence of the inadequate heat treatment. Superposition of two negative influences: material fatigue and inadequate heat treatment, expressed in the cross section at the point of fracture is the main case of the conveyor belt shaft fracture

Analysis of the Drive Shaft Fracture of the Conveyor Belt for Transport of Coal

The conveyor belt for slag and coal transport in the open mine pit "Kolubara" – Serbia is driven by means of two drive drums, attached on separate shafts. Each shaft is driven by two electric motors on both sides. During exploitation, the conveyor belt drive shafts are subjected to torques and transverse forces due to belt tension. The gearboxes and the bearing units on both sides of the drive drum support each shaft. A fracture of one of the drive shafts of the conveyor belt occurred at its connection point with the gearbox. The first part of the paper defines the loads relevant for shaft calculation, based on measurements in different phases of operation and the manufacturer’s data. It is followed by the FEM analysis and fatigue analysis, for the most unfavourable load case. It has been established that the critical stress value has occurred near the connection point between the shaft and the gearbox, in the fracture zone. The second part of the paper presents chemical composition and mechanical properties of material, as well as metallographic examination of fracture surface. The experimental test procedure shows that the fracture has occurred not because of an error in the material but as a consequence of the inadequate heat treatment. Superposition of two negative influences: material fatigue and inadequate heat treatment, expressed in the cross section at the point of fracture is the main case of the conveyor belt shaft fracture