Vol 39, No 10 (2019)

The stress–strain state of rubber components in the internal shock absorbers of a small-diameter supporting roller in a caterpillar system is analyzed. An algorithm for its calculation is proposed. The stress–strain states due to axial compression in roller assembly and the radial operational force are considered. The influence of axial compression of the rubber components on the radial rigidity of the supporting roller is determined.

By three-dimensional modeling, the local heat transfer in the combustion chamber of a traditional diesel is compared with that in a promising hydrogen diesel, which is based on the direct injection of gaseous hydrogen. The local heat transfer in the combustion chamber of a hydrogen diesel is analyzed, because it must be taken into account in the conversion of mass-produced diesel engines.

The elastic torques are investigated with different rolling torques in a rolling-mill drive. The dynamic load on the rolling stand is parametrically analyzed.

Software for recording machining tracks in abrasive lapping is described. The software permits prediction of the shape and magnitude of the tool’s surface wear at the stage of process design, on the basis of the dimensions of the workpiece and the lap, their relative velocity, and the machining trajectory.

The abrasive finishing of monocrystalline lithium niobate is considered. The action of abrasive grains on the surface of the workpiece creates a layer of disintegrated material. The depth F of the disintegrated layer may be calculated as F = 12h, where h is the height of the surface relief, corresponding to the roughness R_max.

A manufacturing technology has been developed for wear-resistant cast-iron grinding balls without shrinkage defects. In this method, the balls are cast in single-use sand–clay molds. A new approach to designing the casting system is developed. By numerical modeling, the time dependence of solidification is derived. As a trial, grinding balls are produced by the proposed technology.

In the machining of steel, metal from the workpiece may build up on the tool’s cutting edge. The influence of such buildup on the roughness of the machined surface in the turning of 40Х steel is simulated. The cutting conditions and the tool geometry are found to affect the surface roughness. The adhesive properties of the machined material are also significant. Vibration in the machine tool does not have a statistically significant influence on the surface roughness. That may be attributed to the rigidity of the equipment employed.

The mechanical properties of 38Х2Н2МА steel components after electric-discharge machining (EDM) are experimentally studied. The strength of workpieces obtained by turning and EDM is compared. The life of samples in few-cycle fatigue is determined. The life of 38Х2Н2МА steel samples after EDM is 30% less than after turning. There is little difference in the strength of 38Х2Н2МА steel samples after EDM and after turning.

The electric-discharge machining (EDM) of VKU-29 composite is experimentally studied. The influence of the machining conditions on the lateral electrode gap (the difference between the width of the slot in the polymer composite produced by EDM and the width of the tool electrode) is determined. The electrode gap observed in the machining of VKU-29 composite is analogous to that observed in the machining of steel workpieces. It depends on the pulse energy. Comparison of graphite, copper, and composite tool electrodes shows that the best surface quality is obtained in the latter case. In EDM by a composite electrode, no traces of damage or fluffing are seen on the machined surface.

The stress arising when melt passes through a filter is determined with different positions of the filter in the mold. The compressive strength of the proposed filter is investigated.