What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
nut is a nut, a part that is screwed together with a bolt or screw for fastening. A component that must be used in all production and manufacturing machinery is divided into carbon steel, stainless steel, non-ferrous metals (such as copper), etc. several types. Chinese name nut Foreign name Crewnut alias Nut properties and bolts or screws screw together to tighten the role of carbon steel, stainless steel, non-ferrous metal standard GB German standard international standard Japanese standard American standard features Steel, stainless steel, copper, alloy, etc.
The cylindrical pin is mainly used for positioning and can also be used for connection. It is fixed in the pin hole by means of interference fit. Cylindrical pins used for positioning are usually not subject to load or a small load, the number is not less than two, distributed in the symmetrical direction of the overall structure of the connected parts, the farther the better, the pin is in each connected part The length is about 1-2 times the minor diameter. Cylindrical pins can also be used as shafts, and a straight shaft can also be used as cylindrical pins or even centering pins. So what's the difference between a shaft and a pin? The shaft can be used to transmit torque, bear bending moment and torque, and the cylindrical pin can be used for positioning, bear extrusion force and shear force. In a sense (such as small equipment), cylindrical pins can also be used as shafts.
At present, drum brakes are usually used for rear brakes of automobiles, and pump parts assemblies are widely used. The traditional assembly method is to use tools such as screwdrivers and retaining ring pliers for assembly. The disadvantage is that the assembly efficiency is low, the accuracy is average, and assembly quality problems are prone to occur, which affects the performance of the product assembly. Now take the brake wheel cylinder assembly with automatic clearance adjustment mechanism produced by our factory as an example to illustrate the installation of the elastic retaining ring
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