Manufacture of threads with variable pitch by using noncircular gears

7th International Conference on Advanced Concepts in Mechanical Engineering

Sltineanu, L.^1 ; Dodun, O.^1 ; Cotea, M.^1 ; Coman, I.^1 ; Nagî, G.^1 ; Beliu, I.^2

Machine Manufacturing Department, Gheorghe Asachi Technical University of Iai, Romania^1

Department of Mechanics and Technologies, Stefan Cel Mare University of Suceava, Romania^2

关键词: Double enveloping;    Geometrical considerations;    Kinematic chain;    Mechanical equipment;    Non-circular gears;    Variable pitch;    Worm gearing;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/147/1/012009/pdf
DOI  :  10.1088/1757-899X/147/1/012009

来源: IOP

【 摘 要 】

There are mechanical equipments in which shafts threaded with variable pitch are included. Such a shaft could be met in the case of worm specific to the double enveloping worm gearing. Over the years, the researchers investigated some possibilities to geometrically define and manufacture the shaft zones characterized by a variable pitch. One of the methods able to facilitate the manufacture of threads with variable pitch is based on the use of noncircular gears in the threading kinematic chain for threading by cutting. In order to design the noncircular gears, the mathematical law of pitch variation has to be known. An analysis of pitch variation based on geometrical considerations was developed in the case of a double enveloping globoid worm. Subsequently, on the bases of a proper situation, a numerical model was determined. In this way, an approximately law of pitch variation was determined and it could be taken into consideration when designing the noncircular gears included in the kinematic chain of the cutting machine tool.