DESIGN OF A TOOL FOR FORMING REGULAR MICRORELIEFS ON THE WORKING SURFACES OF CONNECTING ROD INSERTS

Abstract

The article considers the design of a specialized tool for forming regular microreliefs on the inner working surfaces of connecting rod inserts of internal combustion engines. The relevance of the study is determined by the need to improve the tribological characteristics of friction units, since regular microreliefs can enhance lubricant retention, increase the oil capacity of the surface, and reduce wear intensity. The paper substantiates the design of a surface plastic deformation tool equipped with deforming elements in the form of balls, intended for forming grooves of a regular microrelief on the inner surface of connecting rod inserts of a Volvo V50 1.6 HDI engine during their machining in a holder. The main geometric parameters of the microrelief formation process are determined, the number and arrangement of the deforming elements of the tool are established, and the influence of the ball diameter, their protrusion, and the indentation depth on the width and depth of the grooves is analyzed. The inclination angle of the grooves is determined by the axial feed of the tool.

A dimensional analysis of the tool design was carried out using the method of complete interchangeability by solving the inverse problem of the dimensional chain. Based on the performed calculations, the nominal dimensions and tolerance fields of the closing link of the tool were determined, taking into account the elastic and elastic–plastic deformation of the surface layer material. The proposed tool design provides the possibility of adjusting the protrusion of the deforming elements, which ensures stable formation of the parameters of the regular microrelief. The use of the developed tool makes it possible to form surfaces with an optimal relative area of the microrelief, thereby increasing the oil capacity and operational reliability of connecting rod inserts in internal combustion engines.