Reverse Design And Simulation Analysis Of The Planetary Non-circular Gears Trains Weft Insertion Mechanism Applied On Rapier Loom

As one of the five key components of a rapier loom, the weft insertion mechanismtransforms the constant rotary speed of loom’s spindle into the linear reciprocating motion of therapier head, which guides the weft yarn to enter the shed. There are several kinds of weftinsertion mechanisms used on rapier looms, such as the conjugate cam type, the variable screwpitch type, and the spatial four-linkage type weft insertion mechanisms. The original innovationsand patents of these weft insertion mechanisms are authorized by foreign countries, so the lackof independent innovation restricts the development of domestic loom industry. A novel weftinsertion mechanism researched for rapier looms, named the planetary non-circular gears trainsweft insertion mechanism has been proposed in this paper. The kinematic and dynamic model ofthis new-type weft insertion mechanism has been established, then the optimization andsimulation analysis has been conducted. This research will provide a theoretical foundation forthe research and development of domestic rapier looms.The main contents of this paper are shown as bellow.1) The process of weft insertion on rapier loom was analyzed, and a group of idealkinematic curves was selected as the moving regularity of the rapier head.2) The mathematical models of reverse solution for the planetary non-circular gears trainsweft-insertion mechanism were established. Meanwhile a reverse design and kinematicsimulation software was compiled based on VB. The influences of several structural parametersover the shape of the non-circular gear’s pitch curve was analysed by applying this software.Through the human-computer interaction optimization, a series of preferable parameters wasobtained by taking both the weft insertion process and pitch curve’s shape into consideration.This set of parameters can ensure this mechanism to meet the requirements of weft insertion.3) The formula for calculating contact strength of non-circular gears was derived. The finiteelement model of the contact between two non-circular gears was established by using ANSYSsoftware, in order to verify the correctness of the derived formula. And this formula forcalculating contact strength can provide a efficient method to conduct the strength check of the elliptic gears and non-circular gears applied on this weft insertion mechanism.4) Dynamic models of the planetary non-circular gears trains were established. The toothcontact force as well as the force at each hinge point were calculated conveniently after adynamic analytical software was compiled. Then the dynamic characteristic of this mechanismwas analysed for the further structural design and dynamic optimization of this weft insertionmechanism.5) Three-dimensional modeling, virtual assembly and interference checking of this weftinsertion mechanism were conducted. Virtual prototype technology based on ADAMS is appliedto simulate the motion of this mechanism, with the purpose of verifying the correctness of theestablished kinematical models and dynamic models of the weft insertion mechanism.