What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Standard parts are commonly used parts, which are widely used in various mechanical structures. Among them, the T-track bolt is a common standard part. The existing T-shaped track bolts, especially those used in high-speed railways, are often installed in pre-buried tracks, and the T-shaped track bolts are not easy to install, which may easily cause positional deviation.
Ordinary T-bolts, the bolt head is rectangular, the screw part and the bolt head are T-shaped, and the width of the head is smaller than the width of the opening part of the T-slot, so that the head of the T-bolt can extend from the length of the T-slot. Insert the T-slot into the T-slot at any position in the direction. When the workpiece needs to be fixed, turn the T-bolt 90 degrees so that the length of the head is perpendicular to the T-slot, hook the inside of the opening of the T-slot, and screw it by tightening The nut on the T-bolt threaded rod holds the workpiece in place. The T-bolt of this structure can easily connect the bolt and the base piece quickly, and is widely used, but there are also some shortcomings, due to the contact area between the head of the T-bolt and the inner side of the opening of the T-slot. If it is too small, the frictional resistance is correspondingly small. On the one hand, the bolts are easy to follow the rotation during the process of tightening the nut. Unreliable.
The positioning pin is a pin designed to accurately position the two adjacent parts of the mold in a mold composed of two or more parts. It can be seen that the positioning pin plays a positioning role, and the mold must be accurately synchronized when it is closed. product, and the positioning pin can make the upper and lower molds play a role in accurate positioning. In the mold design and manufacture of Yueluo, the positioning pin is one of the most common parts. Since it is only used for positioning between parts, few people will pay too much attention to it. In the cold stamping process of Yueluo, the dimensional accuracy of the blanking parts depends on the size of the working part of the punch and the concave die, and the dimensional difference between them constitutes the blanking die gap. Gap is an important process parameter for die design, and its size has a great influence on the quality of the section of the blanking part, the blanking force, and the life of the die. If the gap is too large, punching burrs will appear in punching; if the gap is too small, secondary cracks will occur in the section and extrusion burrs will appear, which will make the quality of the section after punching unsatisfactory, and a reasonable gap will not only help the punching section. The improvement of quality also contributes to the improvement of the lifespan of the three-tool.
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 452N. 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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