附录
(英文文献及中英文对照)
The designing features of automobile body
welding fixture
Auto body clamp is required for the amorphous body stamping required to locate and clamp, to form the body components, combined parts, sub-assembly and assembly, While taking advantage of suitable welding method to form their own welding pieces of the whole. Welding fixture welding process is a secondary device, but in the process of mass production car body, the device is essential. It not only can improve welding productivity, but also to ensure the dimensional accuracy of welding products and appearance requirements of the important devices. The assembly and welding fixtures there is no uniform specifications and standardization, are non-standard equipment. Design.and manufacturing process according to the structural characteristcs of the specific models, production conditions and the actual demand from the line of design and manufacturing.
1. asonable decomposition of auto body parts welded together to determine the type of fixture required. Two or more of the stamping process by the assembly and welding of components is obtained by welding together pieces of several related small welding welding large pieces of formed pieces, then welded together to form the following four parts: Around before welding parts, welding parts around the back, floor and roof welding parts welding parts, welding together four pieces of the final welding into vehicle cab assembly. Therefore, according to the cab assembly formation process of the correct welding pieces of reasonably divided, and on this basis, the corresponding pieces of welding fixture design. This will not only help ensure product quality, also can increase welding productivity.
2. Determine the level of automation of assembly and welding fixtures. Annual output depends on the level of automation and assembly and welding fixtures welders bit configuration. Production cycle time mainly by clamping action, the assembly time, welding
time and handling time and other components. Among them, the jig fixture operating time depends on the degree of automation. To improve productivity, consider clamping fixture and release time to complete the action by the cylinder, and between station and station automation transport. But this increases the manufacturing cost of fixtures. Therefore, the design of fixtures to be able to reasonably balance the level of automation and welding fixtures contradiction between the manufacturing cost.
3. For large welding jigs, fixtures must first determine the design basis, with the same car body design basis. Fixture n the location of all the components are determined directly from the design basis, the ultimate guarantee to create a qualified welding tooling structure. According to a preliminary decision height operations fixture floor height, the height of the clamped position; Second, draw the assembly and welding parts diagram, it is included in the station in need of assembly and welding of stamping the solder joint shape and location requirements as the basis for setting fixture; The next step is a reasonable arrangement of fixture position, this must be clearly grasp the stamping of the space shape, composition relationships, assembly and welding sequence and the solder joint layout, rational design of fixture placement and general structure; overall design of the final draw sketches.
4. Rational choice of fixture position. As the car body shape complexity, poor rigidity, deformation, fixture positioning has been introduced on a large number of ways to enhance the rigidity of welded parts, reduce the welding deformation. Positioning of welding fixtures generally include positioning and side positioning of two kinds of holes. Positioning hole punching process to give priority to consider the positioning hole, the size and location of these holes is relatively accurate and reliable; Try to use under the procedures of mounting holes, as these holes the size of the margin of error will affect the next process of the assembly. Therefore, the design of fixtures with positioning holes not only to understand the stamping process, assembly process must also consider the key under the channel size. Large lection of positioning holes as the holes, so that pins can have sufficient strength, or easily broken pins. Stamping on the preferred shape to a reliable, stable surface as a positioning surface, positioned to do as much as possible the use of flat surfaces, but most of the space body stamping surface, which requires the fixture components of the work surface must be positioned with the corresponding surface of the car body consistent shape, so as to ensure the body in the process of assembly and welding shape. Positioning of parts with surface to guarantee a certain accuracy, adjust the position of positioning blocks are coarse
