On calculation and assessment of machine reliability

Abstract

Problems of durability and reliability of machines are of interest not only to scientific constructors and mechanical engineers but also to consumers who operate machines, organize their maintenance and repair. Durability is associated with machine downtime caused by need to determine its performance. Since at the same ones, relatively simple tuning and adjustment operations were performed, and in another, complex installation work is required with replacement of road, parts, and assemblies. Qualitatively, reliability is defined as a property of a mechanical system (machine) to execute, without fail for a specified time, amount of established work, subject to rules of operation. Machines failures are divided into two groups: apparent - accompanying breakdowns of parts, rupture of kinematic chains, destruction of joints; implicit - manifested in deviation of dimensions or parameters that determine quality of work of parts from established or permissible values. The article describes research methodology, which is carried out by quantitative characteristics of reliability of elements. Quantitatively, reliability is determined by probability of completing a task in a timely manner with appropriate quality of work. Then failure rate is determined which shows what proportion of parts from their total number fails during the period under review. Analysis ofequipment failures during periodic tests showed that significant number of them are caused by imperfection and imbalance of established design rules and standards. Thus, it can be noted that reliability is an important indicator, but not sufficient for a full characteristic. The machine must be evaluated for maintainability and durability.