Vivek Nema

Bio: Vivek Nema is an academic researcher from Indian Institute of Technology Kharagpur. The author has contributed to research in topics: Combustion & Diesel fuel. The author has an hindex of 1, co-authored 1 publications receiving 10 citations.

Design and development of strain wave generating cam for a new concept ‘harmonic drive’

Abstract: A split cam design is proposed to solve the problem of assembly of the single piece cam in the flexible raced bearing of an earlier proposed novel harmonic drive system, which shows better torque c...

The strain wave gearing

Abstract: Ein erster und ein zweiter ausen verzahnter Verzahnungsbereich (7, 9) eines Verformungswellgetriebes (1) werden durch einen Wellgenerator (10) in eine elliptische Form verbogen, um in ein erstes bzw. in ein zweites innen verzahntes Zahnrad (2, 4) einzugreifen. Der erste und der zweite ausen verzahnte Verzahnungsbereich (7, 9) werden so verbogen, dass sie elliptische Formen haben, deren Phasen um eine Rotationszentralachse (1a) um 90° gegeneinander verdreht sind. Zwischen dem ersten und dem zweiten ausen verzahnten Verzahnungsbereich (7, 9) ist ein ausen verzahntes Kopplungsverzahnungsbereich (8) ausgebildet, der eine kreisformige Querschnittsform behalt, die sich nicht verbiegt. Der ausen verzahnte Kopplungsverzahnungsbereich (8) wird so auf eingreifende Art und Weise mit einem innen verzahnten Kopplungszahnrad (3) gekoppelt gehalten. Das Verformungswellgetriebe (1) hat eine hohe Eingriffssteifigkeit und ist in der Lage, ein groses Drehmoment zu ubertragen.

An investigation on secondary force contacts of tooth pairs in conventional harmonic drives with involute toothed gear set

Abstract: 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 ge...

Analysis of coning and lubrication at flexspline cup and cam interface in conventional harmonic drives

Abstract: Purpose In a harmonic drive during assembly of its components like strain wave generating (SWG) cam, flexspline (FS) and circular spline, a gap is formed between the cam’s outer surface and the FS cup inner surface due to mismatching. This gap, which is known as “Coning”, plays a vital role in the flow of lubricant at that interface. This paper aims to analyse the coning phenomenon and the lubrication mechanism. Design/methodology/approach In the present investigation, the geometry of the coning gap and its variation with the SWG cam rotation are established. Essentially, the deflection of FS cup and deformation of SWG cam (bearing outer race) are derived to find the gap due to coning. Next, the hydrodynamic lubrication equation is solved to get pressure profiles for this gap under suitable boundary conditions assuming non-Newtonian lubrication. Findings Methods of estimating the coning gap and lubrication pressure profiles are established. Effects of non-Newtonian terms (coupling number and non-dimentionalized characteristic length) and SWG length (finite, long and short) on pressure profiles are also shown. All analyses are done in non-dimensionalized form. Originality/value Establishing the geometry of coning and non-Newtonian hydrodynamic lubrication aspects in the coning in the FS cup and SWG cam interface are the originality of the present investigation.

Failure Analysis of a Flexspline of Harmonic Gear Drive in STC Industrial Robot: Microstructure and Stress Distribution

Abstract: The failure process and failure mechanism of the flexspline in harmonic reducer system after 500h operation were analyzed. The microstructure, element composition and mechanical properties of flexspline were studied by optical microscope (OM), scanning electron microscope (SEM), atomic emission spectrometry (AES), infrared carbon sulfur analyzer and microhardness tester. The stress distribution of the key parts of the flexspline was calculated by LS-DYNA finite element simulation software. The results revealed that the main reason for the failure of the flexspline was the local micro crack and the variation of the dimensional accuracy, the essential reason was grain and ferrite phase inappropriately. In addition, the stress of the failed flexspline was concentrated near the crack, the maximum stress was increased by 26%, which compared well with empirical conclusion. This work can offer a reference for the further improvement of the flexspline.

Double-circular-arc tooth profile design and parametric analysis on the comprehensive performance of the harmonic drive:

Abstract: A tooth profile is of significant importance to the performance of a harmonic drive. Available studies about designing a tooth profile only consider the influence of the tooth profile on the meshin...