Study On The Large Stroke Driving Of Maglev Knitting Needle

The driving force generated by the existing magnetic suspension needle driving structure is too small to make the needle reach the technological height required for weaving production,so that the knitting process is limited.In view of the above problems,this paper proposes a new method to drive the permanent-magnet needle by using the multi-level electromagnetic solenoid.By measuring the position of the permanent-magnet needle in the multi-level electromagnetic solenoid,the current magnitude and direction of the multi energized solenoid can be changed dynamically,so that the permanent-magnet needle will receive more axial electromagnetic force,and then it will have a larger stroke.In this paper,the magnetic field distribution law of single-stage and multi-stage solenoids is compared and analyzed,the change law of magnetic force when the permanent-magnet needle is driven in large stroke is studied,its dynamic behavior is explored,and the key influencing factors of the magnetic suspension needle driving in large stroke are revealedStarting from the distribution of magnetic field produced by the current carrying solenoid,this paper analyzes the magnitude and influencing factors of the electromagnetic force on the permanent magnetic needle in the current carrying solenoid,and obtains the conclusion that the axial electromagnetic force on the permanent magnetic needle in the electrified solenoid is mainly related to the radial magnetic induction intensity of the electrified solenoid.On this basis,through the analysis of the distribution law of the magnetic induction intensity on the internal axis of the multi-stage solenoid,the mathematical model of the axial electromagnetic force on the permanent magnet needle in the electrified solenoid is established,and the dynamic equation of the force on the permanent magnet needle is derived,which provides the key theoretical basis for the study of the movement process of the permanent magnet needle;through the vector analysis of the radial magnetic induction intensity of the solenoid According to the position of the permanent magnet needle in the solenoid,the driving current direction of the multi-stage solenoid can be changed,so that the permanent magnet needle can obtain more axial electromagnetic force to increase the travel of the permanent magnet needle.In this paper,a model of permanent magnet needle driven by multi-level electromagnetic solenoid is designed,and the mathematical model between the height of permanent magnet needle and the acceleration of permanent magnet needle is established.The influence of the pitch size of solenoid and the height of permanent magnet needle on the axial and electromagnetic force of permanent magnet needle is analyzed,simulated and compared,and the large stroke drive of magnetic suspension needle is obtained The results show that the permanent magnet needle is located above the center of the first stage drive solenoid,and the permanent magnet needle can produce a large stroke height of more than 20 mm by changing the current direction.Through the establishment of mathematical model,the current drive strategy of the solenoid is calculated when the permanent magnet knitting needle is suspended at the height of 20 mm,and the simulation analysis is carried out by using the electromagnetic simulation software to verify the rationality and correctness of the drive strategy.