What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, more rivets are used on car tires. Due to the long-term bumps of the car, traditional equipment is prone to loosening during the use process, which affects safety. The above problems need to be improved on traditional equipment, so how to design a Rivets on car tires, this becomes a problem we need to solve.
screw is a common threaded connection part, which is mainly used to fix a part on the connection body. When it is necessary to connect, use the screw to pass through the hole on the connected parts, and screw the external thread on the screw into the connecting body to tighten it; The coupling part is separated from the coupling body. Existing common tools for screw disassembly and assembly are generally adjustable wrenches, open-end wrenches, Torx wrenches, socket wrenches, Allen wrenches, flat-blade screwdrivers, cross-shaped screwdrivers, etc., and a screw can only be disassembled with one or one type of tool. Assembly work; when the types of tools are not complete, the screw disassembly and assembly work is difficult to complete, and the screw disassembly and assembly work is greatly limited by the tools.
Bolt material: 18Cr2Ni4W, 25Cr2MoV steel; bolt specification: M27～M48. Because this kind of steel is easy to form a passivation film on the surface, and this passivation film will make the bolt unable to obtain a good adhesion chemical nickel phosphorus layer, so special pretreatment measures must be taken to remove the film first, and measures should be taken To prevent its regeneration, it is possible to ensure a good bonding force between the plated coating and the substrate. At the same time, due to the large geometric size of the bolt, it increases the difficulty of nickel-phosphorus plating treatment and quality inspection of the process.
Each self-tapping screw is composed of three parts: the head, the shank and the end of the shank. The composition of each self-tapping screw has four major elements: head shape, wrenching method, thread type, and end form. 1. Head Shapes There are various head shapes. There are round head (semi-round head), flat round head, round head flange (with pad), flat round head flange (with pad), pan head, pan head flange (with pad), countersunk head, semi-countersunk head, Cylinder head, spherical cylinder head, horn head, hexagonal head, hexagonal flange head, hexagonal flange (with pad) head, etc. 2. Wrenching method The wrenching method refers to the way of twisting the head of the screw when installing and tightening the screw. There are two basic methods: external wrench and internal wrench. Generally speaking, external wrenching will allow more torque than any form of internal wrench (internal groove). External wrench: hexagon, hexagonal flange surface, hexagonal flange, hexagonal flower shape, etc.; internal wrench: flat groove, cross groove H type, cross groove Z type, cross groove F type, square groove, compound groove, inner flower Key, inner hexagon flower, inner triangle, inner hexagon, inner 12 corner, clutch slot, six-blade slot, high torque cross slot, etc. 3. There are many types of threads, including self-tapping threads (wide thread), machine threads (ordinary threads), drywall screw threads, fiberboard screw threads, and some other special threads. In addition, threads can be divided into single-lead (single-end), double-lead (double-end), multi-lead (multiple-end) and high-low thread double-end threads. 4. Terminal form There are two main types of terminal form: tapered end and flat end. However, according to the needs of use, at the screw-in part of the end, grooves, grooves, incisions or parts with a similar drill shape can be processed with cutting function. In some standards, it is also a tapered end or a flat end, and there are different forms such as a rounded end.
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