Research on the profile modification of power skiving tool for internal gears

Power skiving provides an effective solution and considerable machining efficiency for the machining of internal gears. The tool profile design and the reusability after resharpening is critical in gear machining. In this paper, a tool profile correction method based on the error inverse complement of involute profile is proposed. The mathematical model of involute cutter with rake angle and relief angle is established, and the profile error relative to the target gear is calculated by using the tool of this mathematical model. The distribution of gear profile error is fitted by fifth-order multinomial, and the multinomial function of fitting was attached to the cutter profile. The theoretical error of the target gear profile is in 10e-7mm order of magnitude through the calculation of fewer iterations. The distribution of the coefficient of the error multinomial along the resharpening direction is obtained by linear programming. The result shows that the tool designed by this method has almost negligible error accuracy and good repeatability.

Analysis Of Tip Relief Profiles For Involute Spur Gears

The main goal of this research was to study the influence of involute spur gear tip relief on the contact stress at the engagement meshing point (the begining point of the line of contact A). Different predefined involute spur gears and modification parameters (amount and length of modification) were already available from previous studies (Schmidt 2019). In this study, both the drive and the driven gear has tip relief. The modification of the gear profile was achieved through the modification of the gear rack cutter’s profile. This way the profil modification of the gear profiles are generated during the gear generation (gear planning) process. The gears have been nitrided, so after the gear manufacturing process, the heat treatment did not defrom the modified gear profile. The gear modifications were generated in a CAD system, and the calculations were made with FEM. The results show that the tip relief influences the magnitude of the gear contact stress at the first meshig point. With the use of tip relief modification, the contact stress of the meshing gears can be reduced at the beginning of the meshing line.

TECHNOLOGICAL CAPACITY UPDATING OF CONTINUOUS RUN-IN GEAR GRINDING METHOD

The work purpose consists in the technological capacity updating of the method for cog-wheel continuous run-in gear grinding based on the purpose of efficient modes and characteristics of the worm disk. The investigation methods are based on mathematical modeling and planning experiments. Machining aircraft cylindrical cog-wheels and special samples was carried out on modern NC machines, benches and plants with the use of up-to-date test equipment: coordinate inspection machine KIM R-100 “Klingelnberg”, profile meter MarSurf M300S “Mahr”, optical microscope Axiovert 400MAT “Zeiss”, electronic scanning microscope Tescan Mira3 “Tescan”, micro-hardness gage Micro Met 5104 “Buehler”, X-ray diffractometer Xstress Robot “Stresstech OY”, Barkhausen digital nose analyzer Rollscan 350 “StresstechOY”, plant APOON on the well-known and developed techniques. The research results and novelty. Special strategy and cutting modes at the required characteristics of the combined polish-grinding worm allow ensuring gear profile roughness Ra=0.089 mkm keeping high accuracy of a ring gear (gear profile error Fa=1.6mkm) without gear honing thereby increasing productivity. The quality researches of gear surface layer give grounds for the application of the method for aircraft cog wheels.

Analytical and experimental studies on wear in spur gear running in dry condition

This study was performed to measure the extent of wear of unlubricated spur gears on the involute tooth. Contacts that roll and slide normally undergo wear. When material removal occurs due to surface wear from the gear profile, the surface pressure in the gear profile is redistributed. A mathematical model for predicting wear and wear pattern in spur gear has been developed. The prediction is based on wear rate equation, load shared by the tooth in single-pair contact zone and double-pair contact zone. The distribution of the contact pressure was determined using the Hertzian cylindrical contact theory. For determining the sliding distance of the gears, the two-point observation method (TPOM) was used. Sliding distance at pitch point of gear and pinion was zero, because theoretically at pitch point, both zero sliding and pure rolling occur. The pin on the wear test method was used to obtain the wear rate on the material and simplified to the time of measurement on the gear wear. Taguchi's method for design of experiment was used, which significantly reduced experimental time with less experiment.

Research and manufacture of external non-circular gear-pair with improved cycloid profile of the ellipse

Non-circular gears (NCGs) are known as an alternative to conventional mechanical mechanisms in continuous speed converters. In which, the gear profile is the factor that directly affects the performance and quality meshing of the non-circular gear. However, the types of curves that are being used to generating profiles of the non-circular gears still exist limited in meeting the conditions of undercutting and uniformity of tooth sizes at different positions on the centrode. To optimize the profile of the non-circular gear, the paper presents a new profile in which the traditional involute profile of the non-circular gears is replaced by an improved cycloid curve of the ellipse. The mathematical model of new profile of non-circular gear is formed by eccentric circular shaper cutter with the improved cycloid of the ellipse in accordance with the theory of gearing in consideration of undercutting conditions. Based on the mathematical model established by this research, a program was written in Matlab. On that basis, a pair of non-circular gear was designed and fabricated experimentally on a wire breaker to verify the theory. The results show that with the new tooth profile design scheme, the shortcomings of uneven teeth on the non-circular gear of the traditional studies when using the involute profile of the circle have been overcome.