What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Rivets are nail-shaped objects with a cap on one end: in riveting, the riveted parts are connected by their own deformation or interference. There are many types of rivets, and they are not restricted in form. Commonly used are R-type rivets, fan rivets, blind rivets, tree-shaped rivets Rivets, semi-circular head, flat head, semi-hollow rivets, solid rivets, countersunk head rivets, blind rivets, hollow rivets, these usually use their own deformation to connect the riveted parts, generally less than 8 mm with cold rivets, larger than this size with Hot riveting, but there are exceptions. For example, the nameplate on some locks is riveted by the interference between the rivet and the lock body hole. The rivet pliers are used to cut rivets. The existing rivet pliers have a simple structure and cannot be riveted according to the The user needs to cut a certain length of rivets, and cutting the rivets is time-consuming and labor-intensive, and it is not convenient for people to use.
In response to the above situation, Yueluo uses various methods to fasten the locked nuts and bolts in actual operation, such as super glue, electric welding, secondary reinforcement by perforation, etc., but there is still no way to get it right Solve the phenomenon that the nut is loose and displaced.
At present, the main four kinds of anti-shedding nuts are still prone to falling off. Friction and anti-shedding are in the case of shock, vibration and variable load. At the beginning, the nut will decrease in preload due to relaxation. As the number of vibrations increases, the loss of preload will increase. The force increases slowly, eventually causing the nut to loosen and the threaded connection to fail. The mechanical nut is prevented from falling off by adding a stopper, which makes it inconvenient to disassemble. The riveting and punching prevention is to prevent the separation by welding, bonding, etc. This method can only be disassembled by destroying the bolt pair.
However, for some thin-walled parts (such as metal material parts with a thickness of less than 1mm), the combination of cylindrical pins and edge-cutting positioning pins is used as the positioning method on the workstation equipment. In the process of automatic grasping by mechanical grippers, there are many The disadvantage is that if the positioning accuracy is to be met, it is inconvenient for the parts to be placed in the station utensils, and it is also inconvenient for the mechanical gripper to grasp the parts, and it is easy to cause the phenomenon of positioning pin hook parts when grasping the parts. Abandon the positioning and matching accuracy of pins and holes, but in the process of equipment assembly, due to poor positioning accuracy, another phenomenon will occur, that is, the positioning pins on the mechanical gripper are not aligned with the positioning holes of the workstation equipment, so that the equipment Frequent errors. As shown in Figure 2, when the mechanical gripper grasps thin-walled parts with an inclined angle, if a cylindrical pin is used, there must be a large gap between the cylindrical pin head and the part positioning hole, that is, the diameter A of the part positioning hole must be larger than Only when the diameter B of the cylindrical pin head is larger, the parts can be picked and placed.
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