| Cold heading machine has been widely used in the last century.With the continuous development of modern industry,ordinary low-speed cold heading machine tends to be saturated in the domestic market.The leader of foreign cold heading machine industry has made some achievements in the research of high-speed cold heading machine.As a result,the common low-speed cold upsetting machine produced in China gradually lost its market.At the same time,with the rapid development of domestic automobile industry,the demand for all kinds of high-quality fasteners is also increasing.Therefore,in order to meet the market demand and expand the market share of cold heading machine.It is the main research trend to improve the technology of cold heading equipment,improve the production efficiency and develop highspeed and high-precision cold heading machine.According to the different parts,the mechanical structure of cold upsetting machine is different.The JYX15-30 GA high speed screw cold heading machine studied in this paper mainly produces screws.In this paper,the working principle of high-speed screw cold heading machine was described.According to the forming process of screw,the die structure and movement process of high-speed screw cold upsetting machine were described in detail.At the same time,the movement process of the main drive mechanism,die changing mechanism and feeding mechanism of the high-speed screw cold upsetting machine was introduced.The main drive mechanism is the main movement mechanism in the high-speed screw cold heading machine.Its movement directly determines the output and quality of screws.In this paper,the cold heading force of high-speed screw cold heading machine was calculated.The rigid model and rigid-flexible coupling model of the main transmission mechanism were established.The rigid-flexible coupling model was established by Adams and ANSYS software.The crankshaft was built as a flexible body.The main transmission mechanisms of the two models were simulated respectively.The motion curve of the main transmission mechanism was obtained.Through the comparative analysis of the two models,the rationality of the rigidflexible coupling model was verified.In this paper,the conjugate cam type die changing mechanism for high-speed screw cold upsetting machine was studied.The contour lines of main and return cams in conjugate cam mechanism were designed.At the same time,the pressure angle of the designed conjugate cam was verified,which makes it meet the requirements of use and has good transmission performance.The dynamic model of conjugate cam die changing mechanism was established.The dynamic simulation curve was obtained.At the same time,the collision of conjugate cam mechanism in motion was studied.Finally,the feeding mechanism of high-speed screw cold upsetting machine was studied.According to the motion requirements of the feeding mechanism,the feeding action and the jacking action were modeled and simulated respectively.The impact force of ratchet mechanism in feeding action was studied,and the impact force curve between ratchet and pawl was obtained.At the same time,according to the movement requirements of the top material movement,the time and displacement of the top material movement were studied.Through the simulation,the movement meets the movement requirements of the top material movement.Based on the theory of multi-body system dynamics,this paper studies the modeling and simulation of the main drive mechanism,die changing mechanism and feed mechanism of highspeed screw cold upsetting machine.By comparing the simulation results of rigid model and rigid-flexible coupling model,the rationality of rigid-flexible coupling model was verified.The die changing mechanism was improved.The conjugate cam mechanism was used to replace the structure of single cam and spring.The die changing mechanism is more suitable for high-speed screw cold upsetting machine.By defining the impact force of the ratchet mechanism in the feeding mechanism,the impact force curve between the ratchet and the pawl was obtained.The maximum value and the position of the impact force of ratchet pawl were determined by the curve. |
PDF Full Text Request