The Design of the Welding Junetion Clamp of MotorcarAbstract The text introduces the design method and construction of the welding junction clamp of motorcar. KeyWords: Weldingassembly Base Clamp Loeation 1. Introduction Assembly and welding fixture in the automotive body assembly and welding production line of critical process equipment related to manufacturing quality of the car. In welding production. Assembly and welding fixtures in addition to the completion of this process the parts assembly, positioning, the also served as a test and calibration procedures on the Road, welding parts welding quality of the task, so its design and manufacture of the welding process affects the level of automobile production capacity and product quality.Automotive style vary, welding fixture shape and thus vary widely, but in the design, manufacture, adjustments have in common, you can learn from each other. 2. the structural design of welding fixture Fixture structural design, to ensure that the folder has a good convenience of operation, clamping positioning reliability. Fixture manufacturers also adjusted to ensure easy integration of various parts of the structure surface should allow sufficient room for adjustment to ensure the three-dimensional adjustable. Ensuring the accuracy of the welding quality and welding under the premise of the structure of fixture should be as simple as possible. Fixture design is usually the general use of welded structures, the basic component is divided into three parts, namely base, support the positioning part, clamping parts, for each specific fixture positioning support base and some of the general use of 10 to 20 mm thick steel plate welded structure A3.Clamping part of the normal 10 mm with a thickness of about 45 combination of welded steel plate. Pneumatic and manual clamping part of the two, according to the size of car production clamping method to determine the general high-volume pneumatic clamping, then manually clamping can be used as auxiliary clamping; small quantities in order to reduce the cost of manually clamp mode. Manual clamping is usually manually fast clip, manual quick clip of their products has become the standard, type and quantity needed can be purchased in the market. For some fixtures require apneumatic clamping, but direct use of pneumatic clamping. May damage the workpiece, then, can be manually pressed first place, to give a pneumatic clamping force to clamp the workpiece, which is manual - Pneumatic J the fixture clamping system is installed on a large platform, all guaranteed fixture in the welding position of welding conditions should be consistent with the design of the workpiece coordinate dimensions, which involves the positioning fixture benchmarks. 3 assembly and welding fixtures benchmarks and their choice of support surface 3.1 t flip-chip benchmark test fixture Each fixture must be a fixture coordinate system, in this coordinate system, the coordinates of its base of support size should be supporting the workpiece and the coordinates corresponding to the same size. Fixture coordinate system is established based on fixture side of the child base. Because the whole fixture system to guarantee a space auto welding pieces of three-dimensional coordinate system, so this system in all of the fixture must have a common benchmark, this benchmark is the fixture to install platform that is the X, Y Zuo Biao, each specific fixture in platform location, the corresponding height shall coordinate Z, so that three-dimensional XYZcoordinate system is established. In order to facilitate the installation and measurement fixture, install the platform must have the coordinates of reference, there are generally three types of structure below.3.1.1 The quasi-hole method Tomb Installation of platform design is the four reference holes, each hole in the center of the two connection lines form a coordinate direction, the four holes constitute the coordinates of two perpendicular lines. This, XY plane coordinate system on the set. The establishment of this benchmark is relatively simple, easy to process, but the measurements used in conjunction with the base block. Base block is a rectangular block size of the amount of accurate measurement, the platform is installed into the base hole in the base marketing, reference block off a side close to the two benchmarks to form a coordinate direction. 3.1.2 V-type to be law This approach is in the process to install the platform into each of two 90-degree V-groove, which V-groove of a plane surface perpendicular to the installation of platform, such plane perpendicular to the platform, the two V-groove groove the surface of the form XY plane coordinate system. 3.13 reference block method Reference block using the side perpendicular to the two constitutive three-dimensional XYZ coordinate system, usually a fixture base with 3 to 4 blocks can be directly installed on