Introduction to the types and functions of fasteners

What are the types of fasteners and what role do they play?

Fasteners are a type of mechanical parts that are used for fastening connections and are widely used. It is also the most widely used mechanical base. It is characterized by a wide variety of specifications, different performance uses, and a very high degree of standardization, serialization and generalization. Therefore, some people also refer to a type of fasteners with national standards as standard fasteners.

Common Grent fasteners are generally divided into two categories: standard parts and non-standard parts. According to these two categories, it can also be divided into bolts, screws, nuts, washers, retaining rings, pins, rivets, etc., and different types have different uses.

1. Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread), which needs to be matched with a nut to fasten and connect two parts with through holes. This form of connection is called a bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

2. Stud: a type of fastener without a head, only with external threads on both ends. When connecting, one end of it must be screwed into the part with the internal threaded hole, the other end must pass through the part with the through hole, and then screw the nut, even if the two parts are tightly connected as a whole. This form of connection is called a stud connection, which is also a detachable connection. It is mainly used for occasions where one of the connected parts is thick, requires a compact structure, or is not suitable for bolt connection due to frequent disassembly.

3. Screw: It is also a type of fastener composed of head and screw. It can be divided into three categories according to the purpose: machine screw, set screw and special purpose screw. Machine screws are mainly used for a fastened connection between a part with a fixed threaded hole and a part with a through hole, without nut mating (this connection form is called screw connection, which is also a detachable connection; it can also be Matching with nuts, it is used for fast connection between two parts with through holes.) Set screws are mainly used to fix the relative position between two parts. Special purpose screws, such as eyebolts, are used for hoisting parts.

4. Nuts: with internal threaded holes, generally in the shape of flat hexagonal cylinders, and also in flat square cylinders or flat cylinders, with bolts, studs or machine screws, used to fasten and connect two parts, so that the become a whole. There are two special types of nuts. The first type is high-strength self-locking nuts, which are a classification of self-locking nuts with high strength and reliability. It is mainly based on the introduction of European technology, which is used for road construction machinery, mining machinery, vibration machinery and equipment, etc. At present, there are very few domestic manufacturers of such products. The second type is nylon self-locking nut, which is a new type of high-vibration and anti-loosening fastening parts, which can be used in various mechanical and electrical products with a temperature of -50 to 100 °C. At present, the demand for nylon self-locking nuts in aerospace, aviation, tanks, mining machinery, automobile transportation machinery, agricultural machinery, textile machinery, electrical products and various types of machinery has increased sharply, because its anti-vibration and anti-loosening performance is greatly improved. Compared with other various anti-loosening devices, the vibration life is several times or even dozens of times higher. At present, more than 80% of the accidents of mechanical equipment are caused by loose fasteners, especially in mining machinery, and the use of nylon self-locking nuts can prevent major accidents caused by loose fasteners.

5. Self-tapping screw: Similar to machine screw, but the thread on the screw is a special thread for self-tapping screw. It is used to fasten and connect two thin metal components to make them a whole. Small holes need to be made in advance on the components. Due to the high hardness of this kind of screw, it can be directly screwed into the hole of the component, so that the Form the corresponding internal thread. This form of connection is also a detachable connection.

6. Wood screw: It is also similar to machine screw, but the thread on the screw is a special thread for wood screw, which can be directly screwed into the wooden component (or part), used to connect a metal (or non-metal) with a through hole. The parts are fastened together with a wooden element. This connection is also a detachable connection.

7. Washers: A type of fastener that is in the shape of an oblate ring. It is placed between the supporting surface of the bolt, screw or nut and the surface of the connecting parts, which increases the contact surface area of ​​the connected parts, reduces the pressure per unit area and protects the surface of the connected parts from damage; another type of elastic washer, It can also play a role in preventing the nut from loosening.

8. Retaining ring: It is installed in the shaft groove or hole groove of the machine and equipment, and plays the role of preventing the parts on the shaft or the hole from moving left and right.

9. Pins: mainly used for parts positioning, and some are also used for parts connection, fixing parts, transmitting power or locking other fasteners.

10. Rivet: A type of fastener consisting of a head and a shank, which is used to fasten and connect two parts (or components) with through holes to make them a whole. This form of connection is called rivet connection, or riveting for short. It belongs to the non-detachable connection. Because to separate the two parts that are joined together, the rivets on the parts must be broken.

11. Assemblies and connection pairs: Assemblies refer to a type of fasteners supplied in combination, such as a combination of a certain machine screw (or bolt, self-supplied screw) and a flat washer (or spring washer, lock washer); connection Auxiliary refers to a type of fasteners supplied by a combination of special bolts, nuts and washers, such as high-strength hexagon head bolts for steel structures.

12. Welding nail: a heterogeneous fastener composed of a nail rod and a nail head (or no nail head), which is fixed and connected to a part (or component) by welding so as to be connected with other parts.

What is the main function of fasteners? Fasteners are a type of mechanical parts that are used for fastening connections and are widely used. All kinds of fasteners can be seen on all kinds of machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments and supplies. It is characterized by a wide variety of specifications, different performance uses, and a very high degree of standardization, serialization and generalization. Return to Sohu, see more

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