Design Of Truck Frame Assembly Fixture Based On Flexible Constraint

With the subdivision of the logistics market,the production mode of the commercial truck manufacturing enterprises is gradually evolved from the single variety and the large quantity to the small batch,multi-variety and multi-batch.In this mode,the truck frame assembly collinear production with multiple varieties becomes inevitable.Due to the current frame assembly fixture with the low control precision,small product pass capacity and unharmonious assembly beat and so on,this fixture is difficult to meet the need of technology of high flexible product and has become an urgent problem in the whole production process.So it is great significance to develop a new flexible assembly fixture and its design technology.Based on the analysis of the actual application situation of domestic and foreign similar equipment,the design idea and implementation scheme of the new type of flexible assembly fixture for truck frame is presented in this paper.Combined with a construction project of the truck frame assembly line of FAW,the overall design scheme of the fixture is developed on the basis of the actual process layout of the whole production line.How to use PLC(Programmable Logic Controller),displacement sensor and integrated hydraulic system to control the movement of the assembly fixture is studied,and the automatic adjustment and flexible control of fixture parameter are realized.The main work and innovation of this paper are: 1.The flexible fixture system of truck frame assembly including the mechanical structure,hydraulic system and control system is developed,which completes the reasonable conjunction of this fixture system with the function module of original production line in the production beat,personnel operation and production process.2.By changing the arrangement of the clamping mechanism,adusting the compatibility of key components and optimizing the fixture structure,the complexity of the fixture structure is simplify greatly.3.The function analysis of hydraulic system,parameter design of key system and selection of important hydraulic components are completed in detail.4.The design scheme of automatic control system is presented,the program module is designed and the flexible compensation of structural error is realized.The research conclusions of the flexible fixture structure and control system are of great significance to improve the assembly precision of truck frame assembly,save the investment of equipment,heighten the product quality and production efficiency.The fixture has significant reference for enhancing the reliability,flexiblility and stability of total assembly line of truck manufacturing enterprises and similar equipment in the complex environment.