http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Alexis Johnney Mertens,Selvaraj Senthilvelan 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.2
In the recent years, utilization of non-standard gears have increased due to the improved load carrying capacity and improved durability. However, these non standard gears are manufactured by non-conventional manufacturing process including wire cut electric discharging machining (WEDM). Standard gears are manufactured by conventional machining process, hobbing. This work reported the performance of injection molded polymer gear paired with a steel gear manufactured by conventional hobbing and wire cut electric discharge machining process. WEDM steel gear surface exhibited poor surface topology and higher hardness when compared to that of conventional machined steel gear. Measured net surface temperature of polymer gear at various loads (2-3 Nm) confirmed a temperature rise of 10-15°C when paired with WEDM gear compared to that of hobbed and ground gear. Polymer gear paired with WEDM exhibited inferior fatigue performance when compared to the polymer gear paired with hobbed and ground gear.
Marimuthu Kodeeswaran,Arnika Verma,Rajamanickam Suresh,Selvaraj Senthilvelan 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.8
Gears are generally subjected to uni-directional cyclic loads, however, in applications like actuators of satellite launchers, gears experience bi-directional cyclic loads due to its rotation in both clockwise and counter clockwise directions. In the present study, bidirectional and uni-directional bending fatigue performance of injection molded unreinforced and carbon fiber reinforced polyamide 66 gears were evaluated using a test rig developed in-house. During testing, torque applied and the angular displacement of the gears were continuously recorded. The net surface temperature measured by an infrared camera was higher for the gears subjected to bidirectional loading as compared to uni-directional loading. Reinforced gears exhibited about 84% lower temperature than that of unreinforced gears, due to lesser material hysteresis and better thermal conductivity. Fatigue failure of unreinforced gears exhibited almost straight root cracks and confirmed ductile failure. Fatigue failure of reinforced gears exhibited tortuous crack path due to the existence of reinforced fibers. For both the type of loads, carbon fiber reinforced gears exhibited superior bending performance than unreinforced gears (2-51 times) due to its improved mechanical and thermal properties. Significant fatigue life reduction (83-99%) of the tested gears, were observed when subjected to bi-directional loading when compared to that of uni-directional loading.