Modeling Of The Motion Law Of The Rotating Dobby Opening Mechanism Under Multiple Working Conditions And The Method Of Cam Configuration

Rotary electronic dobby is a high-speed shedding device for modern shuttleless loom,which can effectively improve weaving efficiency and product quality.In this paper,taking the rotating electronic dobby mechanism as the research object,a model of rotational shifting motion for product series design is established,and the cam configuration method of the rotating dobby mechanism under multiple working conditions is discussed.The main research contents and conclusions are as follows:(1)Starting from the configuration of the rotating shifting mechanism,the movement characteristics of the rotating dobby shedding mechanism based on the fixed cam-slider configuration are analyzed,and the reverse model of the motion law of the rotating shifting mechanism is established.Aiming at the adaptability of the rotating shifting mechanism under the condition of multi working conditions weaving,the modeling method based on the standard sine function migration is proposed,and the density migration function of the rotating shifting motion law is established.The simulation results show that the rotation shifting motion law based on the density offset function meets the periodic stop-up-stop motion characteristics of the opening motion,and the transmission performance of the mechanism is good,and the motion characteristics are continuously changing without mutation,which is conducive to the high-speed and stable movement of the loom;the static time and motion characteristic value of the heald frame are inversely proportional to the adjustment coefficient.(2)Based on the principle of motion synthesis,this paper discusses the transformation method of the motion law of rotational shifting,establishes the design model of rotational shifting mechanism,analyzes the influence of the adjustment coefficient on the pressure angle of cam mechanism,the curvature of cam profile,the motion characteristic value of rotor arm and the output dynamic response of rotational speed change mechanism.The results show that with the increase of the adjustment coefficient,the pressure angle of cam mechanism and the rotor arm are immeasurable.The results show that the angular velocity and collision force decrease,the curvature of cam profile,the non dimensional angular jump of rotor arm and the instantaneous collision force of cam contact increase,while the other characteristic values of rotor arm decrease first and then increase;the motion characteristics of rotor arm are continuous and without mutation,which is beneficial to reduce the vibration of mechanism;the adjustment coefficient should be selected in the range of 0.35?0.5.(3)Starting from two aspects of heald frame static time and load,establish the warp tension model of shedding process and the force transfer model of rotating dobby shedding mechanism under complex load,and study the cam configuration method of rotating shifting mechanism under multiple working conditions.The results show that: with the increase of adjustment coefficient,heald frame static time and warp tension decrease,and the adjustment coefficient and driving force of turntable within the selection range.When the adjustment coefficient is large,it is suitable for high speed,light load and narrow width weaving process,and when the adjustment coefficient is small,it is suitable for complex load and wide width weaving process.Combining with the characteristics of rotating speed change mechanism and open weft insertion process,the cam configuration method is proposed,and the correctness of cam configuration method is verified by simulation of weaving conditions of cotton fiber fabric.