Methods for determining the bearing capacity and extreme pressure properties of lubricants used in heavy-loaded tribodynamic couplings of metallurgical machines and units

To solve contact problems related to the study of the interaction between a lubricated or non-lubricated friction pair, we used standard equipment - friction machines and tribometers. However, the use of factory-made research equipment does not always allow us to accurately answer the questions concerning the tribotechnical characteristics of friction and wear processes under specific operating conditions. A review of the literature on the technical capabilities of testing machines showed that their main drawback is the inability to programmatically set the modes of acceleration of the tribological system and tracking slippage in real-time. The study revealed the need to develop a methodology for investigating the extreme pressure properties of liquid lubricants in the tribocoupling acceleration mode, which is caused primarily by the effect of high contact loads acting in the contact areas of friction pairs, e.g. gears, rolling bearings, etc. when technological machines and equipment start and reach the operating speed. The paper considers a modernized friction machine capable of programmatically setting acceleration modes and investigating tribodynamic processes of lubricated frictional couplings. We developed a technique that makes it possible to evaluate the efficiency of a liquid lubricant during acceleration and its effect on the wear of a lubricated contact based on the use of the modernized friction machine.

PENGARUH JENIS BAHAN BAKAR GASOLIN TERHADAP PRESTASI, PEMBAKARAN, GETARAN, KEBISINGAN, DAN EMISI GAS BUANG PADA MESIN TYPE TV-1

The growth of vehicles in Indonesia is dominated by motorcycles. The current compression ratio of the motorcycle is above 9 : 1. Types of gasoline on the market have octane number of 88, 90, 92. The purpose of this study is to analyze engine and combustion performance, noise and vibration, and emissions from gasoline type with a compression ratio of 10 : 1. This study was used engine with 1 cylinder and 4 strokes, sound level meter to measure noise, VibexpertII with acceleration mode for vibration measurement, AGS-688 for exhaust emission test. The test results showed that the break power of all fuels tends to be constant and the smallest SFC is an octane number of 92 (ON 92). The combustion performance of ON 92 also tends to be stable, but noise and vibration of ON 92 are higher. CO and HC emissions of all fuel tend to be constant.

Analysis of starting in horse head system at optimal jerking mode of movement

This article presents the results of an analytical study of the kinematic and power parameters of the movement of the articulated boom system of the crane at the beginning of the movement. The study was carried out during the acceleration of the electric motor of the mechanism for changing the departure from the state of rest to the rotation frequency corresponding to the nominal operating speed of the load movement. In this case, the start of the electric motor occurs, provided that the entire boom system moves along with the load according to the law of jerking optimization. The using of this regularity allows you to completely smooth out the swinging of the load at the beginning of the movement. In addition, towards the end of the acceleration, the same speeds and accelerations are provided between the end point of the crane trunk and the load. This makes it possible to ensure high smoothness of movement of the boom system, and to avoid the load swinging after the rotor of the electric motor reaches the rated speed. Also, a study of static, dynamic and total force in the drive gear rack was carried out. These studies were carried out at different duration of the process of starting the electric motor according to the law of jerking optimization. This made it possible to establish the dependence of the studied kinematic and power parameters on the duration of the transient process. Based on the above, recommendations have been developed for choosing the duration of the acceleration of the electric motor in the mechanism for changing the departure. During of the study, graphs of changes in the studied parameters of the boom system in time were built. Graphical dependencies were obtained with the most acceptable duration of the acceleration mode from the point of view of reducing the dynamic loads on the links of the boom system, improving the technological process of the crane and its ergonomics.

On using the rotor acceleration mode to increase the accuracy of a two-stage gyrocompass

The article considers a two-stage gyrocompass with a rigid torsion suspension of the moving part. The principle of its action is based on balancing the elastic moment of the torsion bars with the gyroscopic moment. When this condition is met, the azimuth of the steady-state position of the rotor axis is calculated from the known kinetic moment , latitude and angular rigidity of the torsion bars, and the measured angle of rotation of the moving part of the gyroscope relative to its initial position. The “aging of the material” of the torsion bars, the effect of temperature on them, etc., leads to an uncontrolled change in the angular stiffness of the torsion bars, which, in turn, leads to an error in determining the position of the meridian. A method is proposed for determining the position of the meridian under conditions when the angular stiffness of the torsion is unknown. The method involves observing the motion of the gyroscope in a mode where the kinetic momentum changes linearly (the rotor accelerates). This movement is associated with the movement of the mathematical model of a two-stage gyrocompass in the same mode in the form of a differential equation of motion or in the form of its solution. As a result of minimizing the discrepancy between the real movement of the gyrocompass and the movement of its mathematical model, the “best estimate” of the parameter characterizing the position of the meridian and the “best estimate” of the angular stiffness of the torsion bars in this dimension are found. The results of modeling the corresponding information processing algorithms are considered. The advantages of the proposed method compared with traditional methods are indicated .