What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
When using a rivet nut, drill a hole corresponding to the outer diameter of the rivet nut on the thin wall, then place the rivet nut on the bolt of the special rivet gun, push the handle to screw in the rivet nut, and put it into the drilled hole. In the workpiece, squeeze the handle, the rivet nut expands, and the deformed skirt bulges and deforms. At this time, the workpiece is tightened. After riveting, the handle is pulled out, the bolt is released from the rivet nut, and the corresponding screw is screwed into the rivet nut threaded hole. , forming a tight riveted body.
According to the force of the connection, it is divided into ordinary and hinged holes. According to the shape of the head: there are hexagonal head, round head, square head, countersunk head and so on. Among them, the hexagonal head is the most commonly used. Generally, countersunk heads are used where connections are required. [1] The English name of the riding bolt is U-bolt. It is a non-standard part. The shape is U-shaped, so it is also called a U-bolt. There are threads on both ends that can be combined with nuts. It is mainly used to fix tubular objects such as water pipes or sheets such as The leaf spring of a car is called a horse-riding bolt because it fixes the object in the same way that a person rides on a horse. According to the length of the thread, it is divided into two categories: full thread and non-full thread. [2] According to the thread type, it is divided into two types: coarse thread and fine thread. The coarse thread is not displayed in the bolt mark. The bolts are divided into eight grades: 3.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, and 12.9 according to their performance grades. Among them, the bolts above grade 8.8 (including grade 8.8) are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenched). + Tempering), commonly known as high-strength bolts, and below grade 8.8 (excluding 8.8) are commonly known as ordinary bolts. [2] Ordinary bolts can be divided into three grades: A, B, and C according to the production accuracy. Grades A and B are refined bolts, and grade C is rough bolts. For connecting bolts for steel structures, unless otherwise specified, they are generally ordinary rough grade C bolts. There are differences in the processing methods of different grades. Usually the corresponding processing methods are as follows: ① The bolts of grade A and B bolts are processed by lathes, with smooth surfaces and accurate dimensions. High, rarely used; ②C-grade bolts are made of unmachined round steel, the size is not accurate enough, and its material property grade is 4.6 or 4.8. The deformation is large during shear connection, but the installation is convenient and the production cost is low. It is mostly used for tensile connection or temporary fixation during installation. [2]
Pins are frequently used parts in the machinery industry, especially in the mold manufacturing industry. With the development of the mold industry, the precision of mold manufacturing and assembly is getting higher and higher, and people are increasingly pursuing high-quality and close molds. Every detail on the mold is constantly improving, and the high-frequency use of the pins forces people to find a safer, simpler and more reliable way to disassemble and assemble.
In the installation of the external electrical components of the high-voltage electrical box, generally, the whole aluminum alloy profile with a T-slot is laid on the shell of the high-voltage electrical box, and then the upper nut is placed in the T-slot, and the bottom of the square nut is provided with a spring , When installing the electrical components, align the mounting holes with the screw holes of the square nut, then screw and tighten the screws to achieve the installation of electrical components. The biggest defect in the above installation process is that the alignment of the mounting hole and the screw hole is not very convenient, and the spring at the bottom of the square nut is easy to be missing. Once the spring is missing or damaged, the square nut cannot be effectively positioned in the T-slot. It makes the alignment of the mounting hole and the screw hole more difficult. Third, the above-mentioned connection and fixing method itself is not particularly ideal.
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