Papers by Keyword: Flexspline

Abstract: The author of the article applied the boundary element method (BEM) to determine stresses occurring in a toothed rim of a flexspline. The relevant numerical calculations were conducted using software developed at the Faculty of Transport of the Silesian University of Technology. The numerical analysis conducted for flexsplines entailed the impact exerted by parameters of an indented toothed flexspline rim (number of teeth, addendum modification coefficient) and of a gear tool (gear tool head curve radius, pressure angle) on values of the stresses occurring at the tooth space bottom. Results of the said calculations have been depicted as curves of dependences between stresses at the tooth space bottom in the function of the number of flexspline rim teeth on constant values of the addendum modification coefficient. The cumulative diagrams developed based on the results of the calculations conducted may provide guidelines as to the manner of designing flexsplines for harmonic drives.

Abstract: The gear teeth have influence on the stresses in flexspline, through the influence coefficients of gear tooth of flexspline. For the purpose of theoretically clarifying this influence, the profile of the gear tooth of the flexspline is simplified as two simple shapes of rectangle and trapezoid. The gear tooth influence on the stresses in the flexspline has been studied and analyzed on this two cases, and the two simplified tooth profiles of rectangle and trapezoid have been compared with each other.

Abstract: The fatigue strength check of the flexspline is the premise and basis of the design of harmonic drive. Fatigue strength of the flexspline with inner and outer gear ring of micro harmonic drive are checked.Through the check calculation and finite element analysis, fatigue strength of inner and outer gear ring can meet the strength requirements.

Abstract: This paper is focused on the micro harmonic drive with a planet type wave generator in which flexspline consists of internal and external gear rings. The mathematical relationship between the coordinates of the points on the tooth profile of the deformed flexspline and that of the undeformed flexspline is derived by carrying on the coordinates transformation. According to this mathematical relationship, the coordinates of the points on the both sides of the tooth profile of every gear tooth of the one forth of the internal and external gear rings of the deformed flexspline are solved with the use of the mathematical software, then the coordinates are imported into the software Pro/E, and connect in a correct order with spline curves, the two curves have been mirrored and extended to finish the 3D modeling of the deformed flespline. At last, the FEM analysis of the deformed flexspline has been carried out.

Abstract: According to the flexible gears damage problem during the work process of the harmonic reducer, a FEM model of the flexible and wave generator was established. On the basis of the mechanics of materials and the finite element theory, a large number of numerical simulations by the use of the finite element software were made. The analysis shows that: the dangerous area is between the flexspline tooth rim and cylinder part. On this basis, the equivalent strain and equivalent stress at different transition fillet were discussed by the use of numerical simulation. The results show that: the equivalent strain and equivalent stress are decrease with the increase of the transition fillet. It provides a basis theory of the optimization design of the flexspline.

Abstract: In order to reduce the weight of harmonic drive (HD), the total volume of flexspline and circular spline was formulated and used as an objection function. Under the constraints including the condition on the strength of flexspline, the condition on averting the tooth top interference, the condition on the transmission ratio of HD and the geometrical constraint conditions of flexspline, a design optimization model with mixed discrete variables was established. For directly applying the optimal design solution of flexspline to manufacture, a manufacture-oriented method for dealing with mixed discrete design variables was used and the established model was solved by using an improved compound genetic algorithm. An optimal design example of flexspline was given and it shows that the proposed method is practical and effective.

Abstract: In harmonic gear mechanism, flexspline’ stress state have a direct impact on selecting wave generator as middle flexible components, this paper firstly simplify flexspline model, construct theory models, then simulate flexspline to compare and analyze in different wave generator, through this，we can select reasonable structure of wave generator from harmonic gear mechanism, provides a new method to design harmonic gear mechanism.

Abstract: The displacement of tooth and the deformation of flexspline of harmonic drive in transmission state were studied by finite element model with shell element. A finite element model of flexspline based on shell element was built with taper teeth on the flexspline, and the contact relationship was defined by contact element between the flexspline and wave generator. The deformation distribution of the flexspline and the deformed position of the teeth on the flexspline were obtained by nonlinear contact analysis in ANSYS environment under the transmission forces according to the loading distribution in the reference. The position of teeth tip and teeth root in front, middle and back plane along teeth length were given by the deformation results. The research shows that the positions and orientations of the teeth in the planes have quite different distributions, which may influence mesh property evidently. The deformation in transmission state in the paper is of importance in heavy loading harmonic drive design because there is no theory results for flexspline in transmission state.

Abstract: Load distribution of the flexspline under alternating dynamic loads is complicated, and it’s difficult to measure the stress of the flexspline by experiment. To study the intensity of the flexspline, operating process of a harmonic drive is simulated based on the contact theory and the explicit algorithm of the finite element method. The parameterized finite element grid of the whole harmonic drive model is realized by Matlab, and then the assembly process of the vave generator is simulated by ABAQUS. Meanwhile, the distribution of the flexspline stress and the load characteristics of the flexspline tooth during dynamic transmission process of a harmonic drive are analyzed. The fatigue fracture position on the flexspline is forecasted according to the simulation results at last.

Abstract: Method to investigate the elastic deformation of a flexspline in harmonic driver was developed under assembly force from wave generator and transmission force. Shell element and tapered beam element were applied to model the flexspline cone and the teeth on the flexspline respectively. Forced displacement of the flexspline in assembly state was imposed by contact analysis between the flexspline and wave generator. According to experimental distribution of tangential forces in transmission state, applying forces at the teeth tips on the flexspline in mesh state, deformation distribution under transmission torque loading was obtained. Simulations of assembly state and transmission state were realized in ANSYS software. In three sections of tooth ring vertical to the axis, the deformation distributions of the flexspline under specified displacement in assembly state were compared with the theory results. Deformation between tip of tooth and neutral layer in assembly state and in transmission state were compared respectively. The deformation results agreed well with the theory results in assembly state, while difference was found in tangential displacement on tooth tips in transmission state, which may influence mesh property evidently under transmission loading.