What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, the convex washers with traditional structures on the market have unreasonable designs and complex structures, and are inconvenient to install and disassemble. After long-term use, they are prone to fracture and deformation due to poor toughness, resulting in short service life and requiring regular downtime for maintenance, affecting assembly. The working efficiency and safety of its equipment are also poor in terms of wear resistance, corrosion resistance, and high temperature resistance. Regular replacement and maintenance also increase the economic cost of production. Therefore, the convex gasket of the existing structure can no longer meet the existing mechanical requirements. The high standard use requirements of assembly auxiliary parts are urgently needed to be solved at present.
In steelmaking plants, the wheels of metallurgical casting crane trolleys used for hanging liquid metal are connected with cardan shafts through flanges. Usually, a keyway is set in the radial direction of the connecting flange, and the keyway is a through groove. The B-type flat key is set in the keyway to transmit torque. During the frequent forward and reverse motion of the wheel, the flange connection bolts are easily loosened. Since the keyway is a through groove, the B-type flat key is easily caused when the flange connection bolts are loosened. It falls off from the keyway of the connecting flange and cannot transmit the torque, which seriously affects the working efficiency of the locomotive. In addition, because the B-type flat key falls off and cannot transmit the torque, the locomotive can only rely on the connecting bolt to transmit the torque when it continues to work. Poor, it is easy to damage and scrap the connecting bolts, and then damage the connecting flanges, requiring frequent replacement and maintenance, high cost, and difficult maintenance.
At present, there are two commonly used nut fixing methods, one is welding fixing: high energy consumption, the welding process easily leads to thread deformation in the nut, which requires re-tapping, which increases the cost, and for aluminum alloy and other materials, the welding process is poor, It is easy to produce welding defects and cannot achieve the function of fastened connection; the other is to pull riveting: in this method, the connection force of the nut is not strong, the reliability is not good, and it is not suitable for thin-walled profiles.
Make further details to make the technical scheme of Guangdong Yueluo Hardware Industry Co., Ltd. easier to understand and master. As shown in Figure 1, Yueluo is a schematic diagram of the thread design structure of the plastic screw of Guangdong Yueluo Hardware Industry Co., Ltd. It can be seen from the figure that this creation mainly controls the tooth angle of the thread. Compared with the normal tooth angle of many self-tapping screws, which are 48 degrees, 60 degrees and 34.5 degrees, the tooth angle of Guangdong Yueluo Hardware Industry Co., Ltd. The profile angle is formed by a 30-degree asymmetrical thread I. In particular, the asymmetrical thread I has a forward thread angle greater than the reverse thread angle. A more preferred embodiment is an asymmetric thread. The tooth profile angle α of the in-line installation is 20 degrees, and the tooth profile angle β of the reverse installation is 10 degrees. With this narrower non-stacked thread, the radial pressure on the plastic material is effectively reduced. In addition, the connecting bottom surface 11 between the screw teeth is designed as a circular arc surface. In the process of forming the self-tapping thread, it is more conducive to the flow of the material and the formation of the thread, and at the same time, the material can be more closely matched with the screw. Moreover, the radial pressure of the casing is relatively uniform, and the formed threads are not easily damaged. Yueluo has been tested by a series of professional parameters. Compared with other traditional screws, the plastic screws designed by Guangdong Yueluo Hardware Industry Co., Ltd. have better radial pressure, shell deformation after installation, load distribution, installation torque, drawing The force distribution, the strength of the pull-out force and the mounting torque range all show advantages. In particular, it can be installed with less torque to achieve the same clamping force and pulling force. Compared with a specific parameter, the thread strength of Delta-PT is 387N, while the thread strength of Guangdong Yueluo Hardware Industry Co., Ltd. reaches 447N. Yueluo can understand the plastic screw structure and implementation of Guangdong Yueluo Hardware Industry Co., Ltd. detailed above. It can be understood that through the improvement of the special thread structure, the radial pressure and installation torque during screw installation are reduced, and the damage to the plastic hole is reduced; And the pull-out resistance of the screw is increased, and it is not easy to appear loose in the assembly. At the same time, the design of the bottom surface of the connection between the threads of the arc optimizes the flow of the material of the installation object, which improves the integrity of the installation connection.
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