The dissertation is devoted to increasing the efficiency of two-sided grinding of the ends bearing rollers ends with oriented wheels with conical calibration sections.
In the first chapter, an overview of the existing methodological approaches to the study and improvement of the processes of grinding the end surfaces of parts with crossed axes of the tool and the part, as well as three-dimensional modeling of the adjustment of grinding wheels, tools, the processes of removing the allowance and the shaping of the machining surface of the part is carried out.
The purpose and main tasks of the research are formulated as a result of the analysis of scientific works.
The second chapter of the dissertation describes the method of conducting experimental research. A modernized two-sided face grinding machine 3342 ADO was used to carry out experimental studies of the process of grinding the end surfaces of bearing rollers.
In the third chapter, mathematical spatial models of the formation of the ends of round parts during grinding with conical calibration sections are developed, it is proved that the geometric error of the length of the part is zero according to the developed grinding scheme. Also, as a result of a more uniform distribution of the allowance along the rough cutting edge of the grinding wheel, the quality of the surface layer of the ends of the parts improves.
The fourth chapter presents the results of an experimental study of the processes of removal of allowance, tool wear, forming accuracy and thermal stress during grinding with oriented wheels in order to verify the reliability of the results obtained during the theoretical study of the process of grinding the end surfaces of bearing rollers with oriented wheels.
Scientific novelty of the obtained results:
1. For the first time, a new method of double-sided grinding of the ends of the bearing rollers with specially oriented and profiled wheels with a conical calibration section was proposed, which reduces the geometric processing error to zero.
2. For the first time, the orientation angles of the grinding headstocks of the machine were determined, at which the geometric error of processing will be zero and the shaping of the end surface will be provided by the method of copying the generating cone, which is perpendicular to the processed surface and lies in the plane passing through the axis of rotation of the wheel.
3. For the first time, mathematical models were developed on the basis of which the dependences of the axial movement of the grinding wheel on the coordinates of the diamond pencil, which rotates together with the feed drum of the machine tool in order to form a rectilinear calibration area, were obtained.
4. For the first time, with the proposed method of processing end surfaces, the allowance is cut only by the rough section of the grinding wheel, and the final accuracy will be formed by the method of copying on the conical section of the wheel at the exit from the processing zone, which ensures minimal forces and thermal stress of the process.
Practical significance of the obtained results:
1. The proposed scheme for adjusting grinding wheels to obtain conical calibration sections provides simultaneous shaping of two wheels and can be used not only on machines equipped with CNC systems, but also without them. Due to the simultaneous editing of two wheels, the preparation time for work is reduced and, accordingly, the overall productivity of the equipment increases.
2. When straightening the rough and finishing sections of the wheel, the angular speed of the feed drum is constant, which ensures the formation of different roughness along the radius line and improves the conditions in the cutting zone. When straightening the calibration section, the angular speed gradually decreases, this ensures the constant development of this part of the surface and improves the quality of grinding the ends.
3. On the basis of the developed general modular spatial models of the ruling tool and the process of adjusting grinding wheels to obtain a conical calibration section, software is proposed for implementation from the CNC system.
4. The minimum permissible length of the calibration section of the grinding wheel during double-sided processing of the ends of round parts is determined.
5. The authorship of the acquirer's scientific developments is confirmed by the obtained utility model patent.
6. Practical recommendations on the use of scientific developments were developed and implemented in production at "Sensor Enterprise" LLC "ZAVOD RAPID" (Chernihiv), PJSC "Cheksil-Avtoservice" (Chernihiv), LLC "Italtex Merino" (Chernihiv) ). The expected economic effect from the implementation of the work results is about UAH 300,000. in a year.
7. The results and methods of the dissertation are used in the educational process of the department of automobile transport and industrial engineering of the Chernihiv Polytechnic National University.
