Design And Optimization Of Key Parts For The Multifunction Braiding Prototype

With the application of three-dimensional braided composite materials in aerospace and biomedical technology,a variety of braiding equipment has been derived.However,the existing braiding machines on the market can braid a fabric with a single cross-section,which cannot achieve a variety of special shapes on a single braiding machine.The braiding of the cross-section,therefore,it is important to study the multifunctional three-dimensional braiding experimental plototype.Based on the first-generation self-developed three-dimensional rotary braiding plototype,this paper designs and optimizes key components such as the conversion device,carrier structure and traction structure to realize the automated production of the three-dimensional braiding plototype.The main research contents are as follows:Aiming at the problem of the collision between the guiding feet and the linear track of the conversion device and the misalignment of the conversion device with the track panel when ch anging the angle.By analyzing the speed and acceleration of the guiding feet in the linear orbital motion of the conversion device,it is found that the speed and acceleration at the center of the orbital position reach the maximum.By optimizing the linear trajectory of the orbital change turntable with arc segments,the spindle cutter speed is distributed sinusoidally across the entire linear trajectory,the peak value is reduced by 4%compared to before optimization,and the position where the accelerat ion peak appears is changed.Meanwhile,reduce the excessive contact impact between the guiding feet and the linear track of the conversion device and the wear of the conversion device and the guiding feet.Regarding the problem that the conversion device change turntable is not tangent to the track notch of the track panel after it is rotated,each of the conversion device change turntables is independently controlled by a swinging cylinder,combined with mechanical positioning,so that the track notch of the conversion device is rotated with the track of the track panel.The notches are tangent,and the ingot knife can smoothly enter the track panel,which solves the problem of misalignment of the conversion device.Aiming at the problems of uneven tension applied to the yarn by traditional carriers and insufficient yarn compensation length,a clockwork spring type carrier is designed to control the forward and reverse rotation of the bobbin through the elastic force of the clockwork spring to realize cont inuous yarn supply and recovery,and the function of the yarn ensures that the yarn tension is stable.Through the analysis of the movement of carrier,it is concluded that the angular velocity of the carrier fluctuates periodically during thebraiding process.According to the relation among angular velocity of carrier,take-off speed and braiding angle,the basis for determination of take-off speed is provided.Aiming at the problem that traditional braiding machines have few take-off types and are not sensitive to take-off speed,traction mechanisms for tubular,ribbon and mesh fabrics are designed respectively.For tubular and belt-shaped fabrics,the traction method of yarn guide ring combined with two guide wheels is adopted;For the mesh fabric,the tra ction method of rubber roller is adopted.At this time,the pressure on the fabric is distributed on the larger contact surface,and the take-off speed is stable.And complete the design of the remaining parts of the three-dimensional braiding machine.