The main reasons for the bolt misalignment are as follows: (1) After the roof welding, the deflection and the tire type deflection do not match, causing the bolt to be displaced up and down. Even if the side bead is installed smoothly, the side bead does not match the roof deflection. Make the interior extremely unattractive. (2) Due to the inaccurate left and right side of the roof when the roof is dropped, the bolt assembly is dislocated to the left and right. When the side is pressed, the end of the strip can not reach the end, and the end of the strip can not be loaded. The bead cut off one cut and the other end has one less cut, which seriously affects the appearance quality and increases working hours.
Solution In order to change the status of bolt misalignment, the technicians tried to solve the problem from the process. During the test, the roof top welding tire was precisely adjusted, and the bolt positioning Gear was also adjusted and reinforced, and then the roof side beam bolts were assembled. The test result is: the first car is quite effective, and the bolts are less misplaced. However, after the second car, the problem of the bolt misalignment gradually becomes the same as before the tire type. serious. The analysis shows that it is not possible to maintain the tire type after the tire type is adjusted. Therefore, it is necessary to adjust the positioning gear after each tire roof is dropped, and then the bolts are assembled, and the workload is quite large.
According to the bolt distribution, in order to effectively solve the problem of the misalignment of the side beam bolts, the current process and positioning method must be changed, so that the positioning gear can be changed with the deflection of the roof, and the positioning gear is not collided when the vehicle is dropped. To this end, the positioning gear must be disengaged from the reversing tire to form an independent positioning. To achieve the above requirements, you can consider using the template to achieve. The tracking test was carried out on the 471 cars with the model set, that is, the roof side beams were tracked and observed according to the improved method. It was found that when the side bead was assembled, there was no bolting phenomenon, and even the knocking was compared. less. This shows that the use of the model set is more effective for ensuring the dimensional accuracy of the roof side beam bolt set. Moreover, the template is not easily deformed and can be used for a long time. Therefore, this process solution is feasible and can be used in mass production.
Because of the large tolerance of the roof length, the model can not be positioned only by one end. It can be centered, grouped in the middle of a group of bolts, and then paired up to the end. The design of the bolt set to the sample is as shown in the figure. The middle set of bolts are positioned by the template (middle), and there are pairs of templates on the left and right sides, and a set of bolts on the ends of the two sides have separate pairs of templates. The design of the sample has two main aspects. One aspect is 123mm positioning, and the other is 540mm and 104mm size positioning. In the past, the process used was that the upper side beam and the roof were integrated, so it could not be positioned 123mm by the lower part of the roof side beam. Therefore, the design of the model used Z-beam profiled plate to locate 123mm.540mm and 104mm. It is realized by the sample hole. The overall size is achieved by a schematic combination of the middle set of centerline and the upper side beam centerline heavy roof side beam bolt set.
Bolt welding process and sample usage The roof side beam bolts are welded together during the roof reversal welding. The center line of the upper side beam can be reflected to the inner side in the stock preparation workshop in advance, so that when the middle set of bolts is set, it can be relied on. Centering the upper side beam. First use the template (middle) group to the middle set of bolts and apply the tack weld. Then use the template (left) to hook the last bolt of the previous set of bolts, and position it by 104mm distance, group the left set of bolts until the end set, according to this method, use the template (left) group to the leftmost end. Group bolts. At the same time, another operator uses the template (right) to group the four sets of bolts on the right. After all the bolt sets have been completed.
By using the template group to the side rail side bolts, it is possible to ensure that the bolts of each side bead are in a straight line, and that the misalignment between the side beads is not large, and the overall appearance quality of the side bead is ensured. Effect After this technical breakthrough, the problem of bolt misalignment that has been plaguing production has been fundamentally solved. Not only the dimensional accuracy of the set of roof bolts is ensured, but also the smooth progress of the post-process is ensured, and the pass rate of the side beam bolts is greatly improved, the waste of raw materials is reduced, and the cutting work time is saved.
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