TECHNOLOGY IMPROVEMENT OF PLAIN BEARINGS’ TECHNICAL CONTROL IN CONSTRUCTION MACHINERY AND EQUIPMENT

Abstract

Introduction. The creation of new machinery and development of modern technologies of its repair in many respects with generation of materials with required properties are defined. Special attention is paid to the economy and widespread introduction of resource-saving and environmentally friendly technologies and to the problems of obtaining and exploitation of new materials, improvement of the goods’ quality.The quality control of materials, which have been used for plain bearings manufacture, during repair action of construction machinery and equipment, as well as reduction of cost and duration of technical control operations implementation are among the issues for repair service organizations. Their solution would enable to increase post-repair resource, cut down failures number, and reduce costs of faults removal in warranty period.Materials and methods. The authors suggest a thermal method of plain bearings materials quality assessment in internal combustion engines. This method is remarkable for its comparative simplicity; it does not require destruction of the material and application of expensive equipment.Results. The dependences of “Cummins” and “Mahle” bushings thickness change on the heating temperature as well as samples warming temperature dependence on test duration have been obtained. According to the derived results such parameters as specific heat and thermal conductivity coefficient are defined. The results of carried out tests show that thermal physic parameters of unoriginal bushings differ from original ones by 11% in thermal conductivity coefficient and by 1.56 times in specific heat.Discussion and conclusions. The calculation of specific heat, thermal conductivity of plain bearings allows to determine the probability of their failure at the stage of entrance control and therefore, to make a more correct decision when choosing parts for execution high-quality repair. As a consequence of temperature change comparison, when bushings samples of “Cummins” and “Mahle” companies are heated, it could be concluded that heating intensity of an original bushing is 17% higher and the reciprocal of bushing temperature gradient under warming is 1.27 times lower in comparison with an unoriginal plain bearing.

Keywords

• plain bearing
• crankshaft journal
• thermal conductivity
• specific heat
• bushing thickness
• temperature