机械毕业设计英文外文翻译354汽车车身焊装夹具的设计要点

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 to fine-tune more complex, this block can be added to fine-tune the positioning function, that is positioned to add a thin spacer block, and gasket thickness is that you can adjust the accuracy. In addition, the set should also be considered when positioning the welding position and the use of welding equipment, welding can not affect the final piece out, but also allows welding clamp or welding torch to reach the location. For the really influential to consider the use of pins and other pins can be active.

5. Properly designed clamping mechanism. When the stamping on the correct positioning of the fixture, in order to maintain the welding process in the assembly of the workpiece position and overcome the elastic deformation of the workpiece, usually requires a certain clamping body. With this device, you can make the workpiece and the bearing surface, workpiece and positioning the workpiece and the workpiece surface and tight fit between. For thickness below 1.2mm steel plate, each clamping point of the clamping force is generally in the range of 300 ~ 750N; For the 1.5 ~ 2.5mm between the stampings, each clamping point of the clamping force in the range of 500 ~ 3000N. To reduce the auxiliary time loading and unloading the workpiece, the clamping device should be fast and efficient installations and multi-point linkage institutions. For sheet metal parts, the clamping force acting on the bearing surface point should be only a good piece of rigid role allowed a few points of support in the plane formed in order to avoid bending or clamping force from the workpiece positioning reference. Also designed to prevent the clamping mechanism to open the clamping grip hand.

6. Other design elements. As the stamping quality checks are sampling, prone to problems. If possible, add in some welding fixture on some auxiliary devices, check the stamping play the role

of critical dimensions. In addition, assembly and welding fixture structure should be easy to operate, saving, security and easy handling characteristics of the workpiece.

汽车车身焊装夹具的设计要点

汽车车身夹具是用来把所需车身冲压件按要求定形、定位并夹紧，组合成车身组件、合件、分总成及总成，同时利用合适的焊接方法使其形成各自焊合件整体。焊接夹具属于焊接工艺过程的辅助装置，但在汽车车身大批量生产过程中，该装置是必不可少的。它不仅可以提高焊接生产率，而且也是保证焊接产品的尺寸精度及外观要求的重要装置。而装焊夹具没有统一规格和标准化，属于非标准设计和制造的工艺装备，要根据具体车型的结构特点、生产条件和实际需求来自行设计与制造。

1、合理分解汽车车身焊合件，确定所需夹具的种类。两种或两种以上的冲压件经装焊工序后得到的部件即为焊合件，几种相关的小焊合件组成大的焊合件，再形成以下四种焊合件：前围焊合件、后侧围焊合件、地板焊合件以及顶盖焊合件，这四种焊合件最终组焊成了汽车驾驶室总成。因此，要根据上述驾驶室总成形成过程进行各种焊合件正确合理地分割，并在此基础上进行相应焊合件夹具的设计。这样，不仅有利于保证产品质量，还可以提高焊接生产率。

2、确定装焊夹具自动化程度的高低。年产量决定于装焊夹具的自动化水平及焊接工位的配置。生产节拍主要由夹具动作时间、装配时间、焊接时间以及搬运时间等组成。其中，夹具动作时间主要取决于夹具的自动化程度。为提高生产率，可以考虑夹

具的夹紧和松开动作由汽缸一次性完成，且工位和工位之间采用自动化运输。但这就提高了夹具的制造成本。因此，设计夹具要能合理地平衡焊接夹具的自动化水平及制造成本之间的矛盾。

3、对于大型焊装夹具，首先必须确定夹具的设计基准，它与汽车车身的设计基准一致。夹具上全部元件的位置都是直接根据设计基准确定的，最终保证制造出合格的焊接工装结构。根据作业高度可初步决定夹具底板的高度，即夹具固定位置的高度；其次绘制出装焊工件图，它包括在此工位上需要装焊的冲压件外形以及要求的焊点位置，以此作为夹具设置的基础；下一步是夹具位置的合理布置，为此必须清楚地把握冲压件的空间形状、组合关系、装焊顺序以及焊点布置，合理设计夹具的安放位置和大致结构；最后绘出总体方案设计草图。

4、合理地选择夹具的定位。由于汽车车身形状复杂、刚性差、易变形，夹具定位上大量采用过定位方式，以增强焊接件刚性，减少焊接变形。焊接夹具的定位一般包括孔定位和面定位两种。孔定位时要优先考虑用冲压工序的定位孔，这些孔的尺寸和位置相对准确可靠；尽量用下道工序的装配孔，因为这些孔的尺寸有误差会影响下道工序的装配。因此，设计夹具用孔定位时不仅要了解冲压工序，还要考虑下道装配工序的关键尺寸。定位孔尽可能选用较大的孔，这样定位销可以有足够的强度，否则定位销容易折断。要优选冲压件上形状可靠、稳定的面作为定位面，尽可能地采用平面做定位面，但车身冲压件大多为空间曲面，这

就要求夹具定位元件的工作表面必须与车身上相应的定位表面形状保持一致，这样才能在装焊过程中保证车身的形状。用面定位的部件要保证一定精度，调整定位块的位置属于粗调，要精确调节较为复杂，为此可以在定位块上增加细调功能，即在定位块上增加很薄的垫片，而垫片的厚度就是可以调整的精度。另外，设置定位时还要考虑焊接位置和所用焊接设备，既不能影响最终焊合件的取出，也可以让焊钳或者焊枪到达焊接位置。对于确实有影响的定位销等要考虑采用可以活动的定位销。

5、正确设计夹紧机构。当冲压件在夹具上正确定位后，为保持焊接过程中各工件的装配位置以及克服工件的弹性变形，通常需要一定的夹紧机构。利用该装置，可以使工件和支承面、工件和定位面以及工件和工件之间紧密贴合。对于1.2mm厚度以下的钢板，每个夹紧点的夹紧力一般在300~750N范围内；对于1.5~2.5mm之间的冲压件，每个夹紧点的夹紧力在500~3000N范围内。为减少装卸工件的辅助时间，夹紧装置应采用高效快速装置和多点联动机构。对于薄板冲压件，夹紧力作用点应作用在支承面上，只有对刚性很好的工件才允许作用在几个支承点所组成的平面内，以免夹紧力使工件弯曲或脱离定位基准。另外设计时要防止在夹紧机构由夹紧到打开时夹住手。

6、其它设计要点。由于冲压件质量检查属于抽检，容易出现问题。如果可能，可以在有些焊接夹具上增加一些辅助装置，起到检查冲压件关键尺寸的作用。另外，装焊夹具结构应具有操

作方便、省力、安全以及工件装卸方便等特点。