Bikash Routh

Bio: Bikash Routh is an academic researcher from VIT University. The author has contributed to research in topics: Harmonic drive & Involute. The author has an hindex of 5, co-authored 10 publications receiving 54 citations. Previous affiliations of Bikash Routh include Indian Institute of Technology Kharagpur & Birla Institute of Technology and Science.

Performance analysis of asymmetric toothed strain wave gear

Abstract: Strain Wave Gear (SWG) or Harmonic Drive (HD) shows moderate performance under symmetrical involute teeth. Teeth interference, excessive teeth meshing, vibration due to improper teeth engagement ar...

Aspects of lubrication at the wave generator - flexspline interface in strain wave gearing units

Abstract: Lubrication aspects, at the Wave Generator (WG)-Flexspline (FS) interface of Strain Wave Gearing or Harmonic Drive (HD), are investigated. Geometries of ‘coning’ of FS and its variation with rotation are established to incorporate in hydrodynamic lubrication equation based on generalized Reynolds equation. Non-Newtonian fluid parameters are also incorporated to cover up analysis for odd lubrication conditions that HD faces in many applications. Effort has been given to develop the analytical expression for separation of lubrication film and other various lubrication conditions at WG/FS interface with respect to few general boundary conditions. Results of analytical solutions are also verified in Ansys-APDL environment.

An analytical method of axial load distribution of deep groove variable clearance radial ball bearings

Abstract: Over the past years, researchers have touched each wave successfully and significant advancement have been introduced in the field of ball bearing. But yet some major aspects of ball bearings need to be divulged like operating radial clearance. The performance and life of the ball bearing significantly depend on its operating clearance. To explore this interest 6206 single row deep groove ball bearing with variable radial clearance is considered in this article. The article basically pacts with the load deformation relationship of variable clearance ball bearing subjected to pure axial load. A closed form solution for load shared by balls is developed using mechanics of solids approach of Hertz contact theory. The acquired result show that under pure axial loading the ball with minimum radial clearance will support maximum axial load. Further, the load shared by 0th ball for variable clearance ball and constant clearance ball bearings is compared. The results and other excerpts from the recommended work will help in unveiling the behavior of ball bearings with variable clearance for combined radial, axial, and moment load.

Spiral spring and planetary gear based regenerative braking system design for bicycles

Abstract: Present paper presents an approach for designing of regenerative braking system for human powered vehicles such as bicycle. Existing regenerative braking system is robust and its application is limited to fuelled vehicles only. Keeping size and weight constraints in mind, a lucid mechanism that incorporates a flat spiral spring, planetary gear system and a one-way clutch as the main components, is investigated here as regenerative braking system. This system stores the kinetic energy in the form of elastic potential energy and converts it back to kinetic energy. The design setup is pliable and can be incorporated with ease on a wheel hub. The mechanism is capable to work in extreme conditions. This system will prove to be cogent in assistance to the driver while acceleration, thus enhancing the overall efficiency of the system.

Load sharing by tooth pairs in involute toothed harmonic drive with conventional wave generator cam

Abstract: A harmonic drive is a two gear epicyclic drive with a gear set of circular ring gear (RG), a flex rimmed external toothed gear (FG) and an oval cam. FG, with oval cam inside, takes non-circular gear shape encounters improper teeth mating with RG, having only two teeth difference. Consequently, interferences occur at several tooth pairs even at no load. These are inherent and obvious. Overcoming such interferences and further with applied load estimation of load sharing by tooth pairs poses a complex problem. In solving it, first, tooth stiffness of internal gear and external gear are derived in the present investigation. A method of estimating the load shared by the multiple tooth pairs in contact is proposed. The load distribution pattern in proportion to the tooth deformation is considered. Load shared by contacting tooth pairs is estimated and stresses in FG cup are found out using FEM. Finally, such results are compared with experimental results, which have good agreement.

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.

A method for detection and quantification of meshing characteristics of harmonic drive gears using computer vision

Abstract: A lack of accurate description of the meshing characteristics and the corresponding frictional mechanism of the harmonic drive gear has limited progress toward modeling the hysteresis stiffness. This paper presents a method for detection and quantification of the meshing characteristics of the harmonic drive gear based on computer vision. First, an experimental set-up that integrates a high speed camera system with a lighting system is developed, and the image processing is adopted to extract and polish the tooth profiles of the meshed teeth pairs in each acquired video sequence. Next, a physical-mathematical model is established to determine the relative positions of the selected tooth pair in the process of the gear engagement, and the combined standard uncertainty is utilized to evaluate the accuracy of the calculated kinematics parameters. Last, the kinematics analysis of the gear engagement under the ultra-low speed condition is performed with our method and previous method, and the influence of the input rotational speed on the results is examined. The results validate the effectiveness of our method, and indicate that the conventional method is not available in the future friction analysis. It is also shown that the engaging-in phase is approximately a uniform motion process, the engaging-out phase is a variable motion process, and these characteristics remain unchanged with the variation of the input rotational speed. Our method affords the ability to understand the frictional mechanism on the meshed contact surfaces of the harmonic drive gear, and also allows for the dynamic monitoring of the meshing properties.

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...