Study On Principle And Technology Of On-Machine Measuring Large Gears

The thesis concerns with a key project supported by both the former Mechanical Industrial Ministry funds and Liaoning province Nature Science Funds. It focus?on studying the principle and techniques of on-machine measuring large gears. In the thesis, characteristics of large gears are analyzed. Because of many teeth large diameter and heaviness of large gears, A method of measuring large gears is different from traditional gear measurement methods, shows as: difficulty for instruments to be fixed and adjusted, serious inertia problems and low measuring efficiency, thus it is very difficult to carry out large gear accuracy measurement. In the thesis, an on-machine measuring method is adopted. Therefore the available resources of machine tools can be effectively used, and the cost of the measuring instrument is greatly reduced. As the direct idea of the thesis, resources of machine tools, advanced mechanical-electronic technology, computer software functions are effectively used, and key problems in measuring large gears are effectively solved. In the process of studying measurement principle, we pay attention to four group of characteristic line: involute group, helix group, straight gcneratrix group, and contact trace group. The characteristic line net formed with any two groups becomes the basis of measuring involute tooth face accuracy. It is correct and effective to use the two groups of involute and straight generattix, both for measuring spur gears and for measuring helix gears. In the thesis, a rack-head-on-machine measuring method is first put forward. As a feature of the thesis, the method accords with large gear characteristics, the instrument dimensions can be greatly reduced, and the measuring operation is convenient. It is a part of the theory study that an error-reading system and an error- variation equation are established in the light of the measuring process of the rack-head method. It is mentioned that measured gear errors, machine tool errors and the instrument manufacturing and fixing errors can result in engagement variation, and measured gear errors are obtained by measuring the variation. The equation becomes the important basis of design, manufacture, adjustment, precision analysis of the measurement system prototype. In order to put the rack-head-on-machine measuring large gear method LI L into practice, key problems, such as measuring dev:ce precision fix to the machine tool, precision angle measurement eccentric compensation, and data processing, are effectively solved. For example, in order to solve the problem of line value amplification in angle measurement, the high transmit ratio friction disc angle measurement device is made. And the practical trial result is considerable. Using the high accurate electronic level meter as an adjusting tool. the adjusting operation can be convenient and the Hgti adjusting accuracy can be obtained. At last, the design, manufacture, and trial of measurement system prototype instrument are carried out, the result indicate that the measurement principle is correct, the measurement techniques are practicable, and the prospect of the rack-head-on-machine measurement method is bright.