Vibration characteristics of tractor gearboxes

Abstract

Problem. Improving the efficiency, quality, reliability and economy of tractor equipment is one of the most important tasks of modern society. This is due to the fact that in agriculture, tractors can perform up to 80% of various operations. The cost of production, product quality, compliance with the conditions of technological operations, etc. depend on the properties and reliability of tractors. The main factor limiting the effective use of tractors in agriculture is the problem of insufficient reliability of tractors, namely, the reliability of its individual components. One of the most important units is its gearbox. The existing methods for diagnosing tractor gearboxes are designed to detect damage, but they are not able to determine the quality of the gearbox at the design and manufacturing stage. Such an opportunity would greatly simplify the process of diagnosing tractor boxes. Goal. The purpose of the research is to assess the quality of design and manufacture of tractor boxes according to their vibration characteristics by identifying design and manufacturing defects, which will allow developing the ways to improve them. Methodology. Methods for detecting statistical data on the boundary values of structural vibrational parameters and their connection with the technical condition of tractors were used. Experimental research methods and mathematical methods for processing and modulating the results obtained were used as well as the methods of statistical calculation and comparison of vibration characteristics with permissible vibrations that do not affect the acceleration of the process of tractor parts wear. Results. Experimental studies of vibro-diagnostic characteristics of tractors were carried out. Studies were made to measure vibration diagnostic indicators; a spectral analysis of gearbox vibration was carried out. An assessment of the quality of manufacturing parts and assembly of tractor gearboxes was made. Such an assessment was carried out by analyzing the spread of the maximum and minimum vibration levels for a sample of gearboxes. Originality. An assessment was made of the possibilities of reducing vibration levels by observing the technology for the production of tractor boxes. This assessment was based on the analysis of minimum vibration levels of tractor boxes. Statistical processing of the results of experimental studies was carried out with the determination of the arithmetic mean, minimum and maximum vibrations, and the standard deviations of the vibration of gearboxes when the fourth gear of the third (transport) range is engaged. Practical value. Vibro-diagnostic characteristics of tractor boxes make it possible to evaluate the quality of design and manufacture by vibration levels. It was established that the vibration levels of boxes at the manufacturing stage reach 85-113 dB and exceed the permissible vibrations by 10-25 dB. The main sources of gearbox vibration are: defects in the quality of gears and bearing assemblies; their assembly, the use of low-quality bearings, large clearances of bearing fit in the housing, and the problem of gearbox assembly technology.