Vpliv kontaktnih pogojev in prednapetja na lastno dinamiko sestava zaganjalnika

Šulin, Arlena (author), Čepon, Gregor (mentor)

Zaganjalnik je ključna komponenta za zagon avtomobilskih motorjev. Vibracije, ki so stalno prisotne pri obratovanju motorja, se prenašajo tudi na zaganjalnik in posledično vplivajo na njegovo delovanje. Poznavanje dinamskih lastnosti je tako ključno za določitev hitrosti motorja, pri katerih pride zaganjalnik v resonanco, za optimizacijo geometrije in posledično zagotavljanje funkcije. Pri modeliranju problema se srečamo z vprašanjem, kako definirati kontakte med sestavnimi deli in nadomestiti model vzmeti s silo prednapetja, da se čim bolj približamo realnemu stanju. V okviru zaključne naloge smo za poenostavitev simulacije predpostavili, da so vsi sestavni deli med sabo zlepljeni. Vijačno vzmet, ki drži krtačko v stiku s komutatorjem smo modelirali kot silo prednapetja, pri čemer smo obravnavali tako stanje pred in po obrabi krtačk. Izvedena je bila modelna analiza za 4 različne modele, ki se razlikujejo v prisotnosti vpliva komutatorja, sile prednapetja in obrabe krtačk. Zabeleženih je bilo prvih deset neničelnih lastnih frekvenc vsakega modela in pripadajoče lastne oblike. Ugotovili smo, da ima na izračunane rezultate največji vpliv kontaktna togost med sestavnimi deli. Določili smo sestavne dele, na katerih se pojavijo največe deformacije pri določeni lastni frekvenci in njihove vrednosti.

• Language: Slovenian
• Keywords: zaganjalnik, modalna analiza, lastne frekvence, komutatorji, prednapetje, obraba krtačk
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [A. Šulin]
• Year: 2020
• Number of pages: XVI, 43 str.
• PID: 20.500.12556/RUL-117206
• UDC: 62-57:621.3.047(043.2)
• COBISS.SI-ID: 21916163
• Publication date in RUL: 02.07.2020

ŠULIN, Arlena, 2020, Vpliv kontaktnih pogojev in prednapetja na lastno dinamiko sestava zaganjalnika [online]. Bachelor’s thesis. Ljubljana : A. Šulin. [Accessed 7 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=117206

Secondary language

• Language: English
• Title: Influence of contact formulation and prestress on the dynamics of car starter assembly

Abstract

Car starter is a key component for starting car engines. Vibrations, that are constantly presented during engine operation, are transmitted to the starter and consequently affect its operation. Knowledge of the dynamic properties is thus crucial for determining the motor speeds at which the starter resonates, for optimizing the geometry and providing the function. When modeling the problem, we encounter the question of how to define the contacts between the components and replace the spring model with a prestress force, in order to get as close as possible to the real state. In the final task, to simplify the simulation, we assumed that all components are glued together. The helical spring holding the brush in contact with the commutator was modeled as a prestressing force, considering both the condition before and after brush wear. A model analysis was performed for 4 different models, which differ in the presence of commutator influence, prestressing force, and brush wear. The first ten non-zero natural frequencies of each model and the corresponding natural forms were obtained. Contact stiffness between the components was determined to have the greatest influence on the calculated results. Furthermore, the components on which the largest deformations occur at a certain natural frequency and their values were recorded.

• Keywords: car starter, modal analysis, natural frequencies, commutators, prestress, brush wear