What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
High-strength bolt connection has the advantages of simple construction, good mechanical performance, disassembly and replacement, fatigue resistance, and no loosening under dynamic load. It is a promising connection method. High-strength bolts use a special wrench to tighten the nut, so that the bolt generates a huge and controlled pre-tension. Under the action of pre-pressure, a large frictional force will be generated along the surface of the connected parts. Obviously, as long as the axial force is less than this frictional force, the components will not slip and the connection will not be damaged. This is the high-strength bolt connection. principle. High-strength bolted connections rely on the friction between the contact surfaces of the connectors to prevent them from sliding each other. In order to make the contact surfaces have sufficient friction, it is necessary to increase the clamping force of the components and increase the friction coefficient of the contact surfaces of the components. The clamping force between the components is achieved by applying pretension to the bolts, so the bolts must be made of high-strength steel, which is why it is called high-strength bolted connections. In high-strength bolted connections, the friction coefficient has a great influence on the bearing capacity. Tests show that the coefficient of friction is mainly affected by the form of the contact surface and the material of the components. In order to increase the friction coefficient of the contact surface, methods such as sandblasting and wire brush cleaning are often used to treat the contact surface of the components within the connection range during construction.
The inch thread is the thread size marked in inch. According to the shape, it is divided into two types: cylindrical and conical; according to the tooth angle, it is divided into two types: 55° and 60°. The 1/4, 1/2, 1/8 marks in the thread refer to the diameter of the thread size in inches. One inch equals 8 cents, 1/4 inch equals 2 cents, and so on.
As shown in Figures 1 and 2, Yueluo is an automatic locking screw. From bottom to top, there are screw head 1 with external thread, screw rod and nut 3. The screw rod is a hollow screw rod 2, and the hollow screw There are long holes 7 on both sides of the rod 2, the width of the long hole 7 is smaller than the inner diameter of the hollow screw rod 2, and a spring 4 is arranged in the inner cavity of the hollow screw rod 2, and the spring 4 is not smaller than the hollow screw rod 2 in the free extension state. The upper end of the spring 4 is provided with a plug 5, the distance between the two wings 6 of the plug 5 is greater than the diameter of the nut 3, and the two wings 6 of the plug 5 protrude out of the hollow screw rod 2 through the long hole 7. When using the Yueluo, you only need to compress the spring through the two wings, insert the U-shaped clip after the neutral position is exposed, and then release the two wings, the spring will automatically return and compress the U-shaped clip, which is easy to use, safe and reliable. Claim 6. An automatic locking screw, from bottom to top, is a screw head, a screw rod and a nut provided with an external thread, characterized in that the screw rod is a hollow screw rod, and both sides of the hollow screw rod are respectively provided with Long hole, the width of the long hole is smaller than the inner diameter of the hollow screw rod, the inner cavity of the hollow screw rod is provided with a spring, the upper end of the spring is provided with a plug, and the two wings of the plug protrude out of the hollow screw rod through the long hole.
(+): Cross slot (-): Slotted slot (T): Chrysanthemum slot (H): Hexagon socket (PZ): Bevel slot (+-): +- slot (Y): Y-shaped slot (H) : H-groove (L): Back-stop tooth (WIS): Single-moving spring washer (WIF): Single-moving flat washer (WIT): Single-moving external tooth washer (W2SF): Double-moving flat washer (W=6mm ): Washer outer diameter equal to 6mm (SUS): Stainless steel (Cu): Brass (Br): Red copper (8.8): Grade 8.8 screw (10.9): Grade 10.9 screw (12.9): Grade 12.9 screw (R): Other Notes
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