Causes of the in-service damage to hydrocylinder liners were investigated, and the requirements to their working surfaces were systematized. Roughness parameter Ra was found not to provide a precise estimate of the surface quality because its reduction did not affect surface microgeometry. Additionally, the surface quality was assessed by the Abbott-Firestone curve during the finishing operation. The optimized manufacturing technology for obtaining hydrocylinder liners was offered based on having the required microgeometry and surface quality provided by cutting operations. The quality and service characteristics of internal surfaces of hydrocylinder liners were improved by changing technological operations. In particular, the semi-finish turning was chosen to provide for the surface roughness parameter Ra within 6.3–8.0 μm and the roughness pitch parameter S within 0.4–0.6 mm and homogeneous surface structure. The finishing rolling was replaced by burnishing to form a regular microrelief.

https://www.mdpi.com/2075-1702/9/6/116/pdf

Optimizing the Formation of Hydraulic Cylinder Surfaces, Taking into Account Their Microrelief Topography Analyzed during Different Operations

The cross-sectional curvature and shape (inner and outer) of a cylindrical surface formed by turning have an effect on the roughness parameter—the arithmetic mean deviation of the Ra profile. The main regularities in this influence are analyzed in this article. The authors investigated specially designed test specimens using their own method, which excludes the influence of other parameters on the roughness forming process. The diameters of the cylindrical surfaces of test specimens were selected taking into account the spindle rotation speed of the lathe. As a result, these surfaces were machined at practically the same cutting speed when performing the final processing step. The Grebbs criterion was used to evaluate the uniformity of surface roughness obtained experimentally.

Influence of Curvature and Cross-sectional Shape of Cylindrical Surface Formed by Turning on Its Roughness

Based on the experimental data on the roughness parameter Ra, which stands for the mean arithmetic deviation of the profile, as obtained in the process of turning test specimens from different materials with constant elements of the cutting mode (depth a and velocity v) and structural-geometric parameters of the cutting tool, but with different feed rates f, the probability-statistical method for estimating the influence of feed rate f on the resulting surface roughness by the parameter Ra is proposed using the theory of a small sample.

Probability-Statistical Estimation Method of Feed Influence on As-Turned Finish of Steels and Non-Ferrous Metals

Physical and mechanical regularities in the effect of certain processing operations on the shape and roughness of the hydraulic cylinder surface are found. The mechanisms of the spatial self-organization of the relief and surface of bearings under conditions of false brinelling are summarized and analyzed. The data obtained can be used for further scientific generalization or prediction and diagnostics of the surface condition of load-carrying and support elements of mechanical systems under study.

https://www.ije.ir/article_72993_1568ec280add7a5c83a3a23c1ec36633.pdf

Analysis of inner surface roughness parameters of load-carrying and support elements of mechanical systems (research note)

According to analysis of the diagram an hour-long traffic vehicles intensity determined the directions of improvement functioning of the road network of the city, by redistribution of traffic streams on sections of the road network by optimization traffic light cycles. Traffic lights cycles proposed to distribute by analyzing the distribution laws of traffic streams at crossroads during the day. By analyzing of statistical data for characteristics determination of distribution proposed to use a small sample theory that provides to get a reliable data in a short period of time. Evaluation of the effectiveness of implementation proposed measures is realizing by Student and Fisher criterions.

/pdf/ways-of-improvement-of-the-city-road-network-functioning-2n41qne5lp.pdf

Ways of improvement of the city road network functioning

It was proposed to estimate the accuracy of the hydro-cylinder cross-section shapes basing on the analysis of the circle diagram of their inner cylindrical surfaces, formed by the manufacturing operations, such as rough and semi-finishing boring and finishing paying-out, taking advantage of the method of deflection approximation from the circle by the Fourier’s trigonometric series in the gap [0, 2π].Characteristics of the deflection dispersion of the radius-vector as the random value (average value, dispersion, amplitude spectrum) have been obtained for every circle diagram separately. It is proposed to present these characteristics as random values.Dependences for finding mathematic expectation and dispersion for the lot of parts, machined at every of the available manufacturing operation, have been obtained for certain number of samples and circle diagrams, taking advantage of the small sampling theory, the method of rectangular engagement in particular.The effectiveness of manufacturing operations has been estimated according to the Student and Fisher t-test. Availability of the advantageous or disadvantageous manufacturing heredity of the hydrocylinder cross-section shape has been found.As the result of carried out experimental investigations and processing of the obtained statistic data on the inner cylindrical surface of the truck hoist crane hydrocylinder KTA-25, produced by the company “Drogobych truck crane plant” (Ukraine), the need to improve the manufacturing operation of the semi-finishing boring has been analysed.Copyright © 2014 by ASME

Volodymyr Krupa

Papers

Technological Heredity and Accuracy of the Cross-Section Shapes of the Hydro-Cylinder Cylindrical Surfaces