“…For example, the outer spline of the SWG has been replaced with low density materials, such as aluminum, that have been coated with hard materials to improve the wear performance of aluminum1. Some research has focused on changing the flexspline material by using carbon-fiber/steel composites, high-strength polymers or a variety of metal alloys45. As such, research in SWGs primarily focuses on how to (1) lower cost, (2) achieve better performance in the intended environment, (3) lower mass, (4) integrate new materials and (5) make smaller drives.…”
The use of bulk metallic glasses (BMGs) as the flexspline in strain wave gears (SWGs), also known as harmonic drives, is presented. SWGs are unique, ultra-precision gearboxes that function through the elastic flexing of a thin-walled cup, called a flexspline. The current research demonstrates that BMGs can be cast at extremely low cost relative to machining and can be implemented into SWGs as an alternative to steel. This approach may significantly reduce the cost of SWGs, enabling lower-cost robotics. The attractive properties of BMGs, such as hardness, elastic limit and yield strength, may also be suitable for extreme environment applications in spacecraft.
“…For example, the outer spline of the SWG has been replaced with low density materials, such as aluminum, that have been coated with hard materials to improve the wear performance of aluminum1. Some research has focused on changing the flexspline material by using carbon-fiber/steel composites, high-strength polymers or a variety of metal alloys45. As such, research in SWGs primarily focuses on how to (1) lower cost, (2) achieve better performance in the intended environment, (3) lower mass, (4) integrate new materials and (5) make smaller drives.…”
The use of bulk metallic glasses (BMGs) as the flexspline in strain wave gears (SWGs), also known as harmonic drives, is presented. SWGs are unique, ultra-precision gearboxes that function through the elastic flexing of a thin-walled cup, called a flexspline. The current research demonstrates that BMGs can be cast at extremely low cost relative to machining and can be implemented into SWGs as an alternative to steel. This approach may significantly reduce the cost of SWGs, enabling lower-cost robotics. The attractive properties of BMGs, such as hardness, elastic limit and yield strength, may also be suitable for extreme environment applications in spacecraft.
“…For the improvement of performances, load sharing by teeth in contacts, tooth stresses, rim (cup of FS) deformation, and their effects on dynamic performance and vibration were studied. 10–12 Improvement of FS material and composite structures were proposed. 11,12 Such a design technique was also examined earlier for similar machines like cycloid type HDs.…”
Section: Introductionmentioning
confidence: 99%
“…10–12 Improvement of FS material and composite structures were proposed. 11,12 Such a design technique was also examined earlier for similar machines like cycloid type HDs. 13 Figure 1.Harmonic drive and its components.…”
Originally fixed and uniform circular pitches of flex spline (FS) teeth of a ‘Strain Wave Gearing’ or ‘Harmonic Drive’ (HD) experience variations in pitch lengths when teeth move on ‘strain wave generating’ oval-shaped cam. This is due to varying root deformations of teeth. In case of teeth with widely used involute profile, away from the contacts on line of action through pitch point, they definitely experience force closeness to or separation from the circular spline’s (CS) originally conjugate tooth. We have estimated the deformed pitch distances at no load considering that FS teeth remain rigid while the rim deforms. The geometry of the oval-shaped pitch curve which is parallel to the elliptical outer profile of the cam is also defined. Similarly to maintain an elliptical pitch curve of FS, the oval cam is also defined. Both cases of tooth mesh of undeformed FS with CS and tooth mesh of deformed FS with CS, with involute teeth, are considered to find out tooth positions. Geometries of involute teeth profiles in mesh are examined and compared considering oval-shaped (on deformation) base drum of FS, whereas the base circle of the CS remained circular.
“…The flexspline it is the main component of a harmonic drive, which can generate a repeated vibration by the wave generator. With this a reason, the flexspline should have flexibility and good vibration characteristics [2][3][4].…”
Section: Introductionmentioning
confidence: 99%
“…That may significantly improve its mechanical properties in this area, because the composite material has a high specific strength, a high stiffness and a high damping capacity [2,5]. An example of such solution and a description of the technological process of producing such flexspline are presented in work [3]. …”
The computer analysis of the influence of flexspline materials at the strength of the flexspline was performed for two and three dimensional models using the finite element method and MSC Patran/Nastran software. Calculations were conducted in two steps. The first one concerns two dimensional models on the contact between the flexspline and the wave generator. The second concerns three dimensional models of flexspline. The application of steel and steel-composite materials as material of the flexspline in harmonic drive was analysed. In calculations were used two types of composites with an epoxy resin, reinforced by the carbon-fiber or the glass-fiber. The preliminary study of stresses for the developed models was made. The steel-composite hybrid flexspline as compared to conventional steel flexspline showed a decrease of maximum stress in the analyzed dangerous cross-sections. Shapes and the frequency of vibration of the flexsplines were also calculated. The impact of stacking fiber angle on the frequency of vibration in the tested flexsplines is negligible.Keywords: materials, flexspline, harmonic drive, finite element method Przeprowadzono analizę komputerową wpływu materiałów kół podatnych na ich wytrzymałość przy pomocy dwu i trój-wymiarowych modeli wykorzystując metodę elementów skończonych oraz oprogramowanie MSC Patran/Nastran. Obliczenia przeprowadzono w dwóch etapach. Pierwszy z nich dotyczył dwuwymiarowych modeli kontaktu koła podatnego i generatora fali. Drugi dotyczył trójwymiarowych modeli kół podatnych. Przeprowadzono analizę zastosowania stalowych oraz stalowo-kompozytowych materiałów na koła podatne przekładni falowej. W obliczeniach wykorzystano dwa rodzaje kompozytów z osnową z żywicy epoksydowej, zbrojonej włóknem węglowym lub włóknem szklanym. Dla opracowanych modeli została wykonana wstępna analiza stanu naprężenia. Analizując otrzymane wyniki obliczeń symulacyjnych przyjętych rozwiązań konstrukcyjnych kół podatnych stwierdzono zmniejszenie wartości naprężeń w rozpatrywanych przekrojach stalowo-kompozytowych kół podatnych w porównaniu z tradycyjnymi kołami stalowymi. Wyznaczono ponadto postacie i częstotliwości drgań badanych kół podatnych. Stwierdzono że, wpływ kąta ułożenia włókien na częstotliwości drgań badanych kół podatnych jest nieznaczny.
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