Standard And Material Selection Of Grommets

- Aug 02, 2017-



Standard and material selection of Grommets

Grommetss main effect is to reduce pressure on the surface compressive stress, protect by fitting of surface, can be used to prevent the loose connection vice locking spring washer and more tooth lock washer, Grommets round nut and lock washer with conical spring washer, saddle, waveform, flat washer is mainly used to decrease the pressure, when some parts of the screw down the axial force is very big, easy to make the pressing dish washer, then can use material and improve the hardness to solve. The locking effect of the spring washer is generally, the important part is as little or no use as possible, and the self-locking structure is adopted. For high speed screw (pneumatic or electric) spring washer, had better use the washer of surface phosphating treatment, improve its wearing performance, Grommets otherwise easy friction heat and burn out or mouth, or even damaged by surface fitting. The spring washer should not be used for the veneer joints. According to statistics, the spring washer is used less and less in the car.

The connection tooth shape in the tooth elastic Grommets is large and uniform, and it is used more in the automobile industry, while the interval tooth type is less. For spring washer and elastic Grommets, the 60, 70 steel and 65Mn steel in gb699-1999 "high quality carbon structural steel" can be selected according to the national standard. The standard of flat Grommets in China is 9 items, from 2000-2002 respectively, the GB/t97.3-2000, GB/t5286-2001, GB/t96-2002, GB/t96.2-2002, GB/t96.2-2002, GB/t97.2-2002, GB/t97.2-2002, GB/t97.2-2002, GB/t97.2-2002, GB/t97.2-2002, GB/t97.2-2002 and GB/t5287-2002, etc. According to the performance level of the flat Grommets, the author recommends using materials: for 100HV, the surface hardness can reach about 110HV, such as ST12, ST13 and Q235, Q215, Q195 and so on. For the type 08F, 08Al, 10 and 10F of 140HV, the surface hardness can reach about 140HV. For the 200HV and 300HV class, we should choose 45, 50, 60, 70 steel or 65Mn steel, which can be tempered by heat treatment to reach 200 ~ 300HV and 300 ~ 400HV technical requirements. Low carbon steel is used for the flat washers of 100HV and 140HV according to the standard. The general enterprise chooses the material most is to use baosteel material, facilitate cold stamping.

The combined Grommets, which is made of rubber ring and metal ring as a whole, is a sealing ring used to seal threads and flange connections, including a metal ring and a rubber Grommets. Metal ring anti-rust treatment, rubber ring is generally used for oil - resistant butyronitrile or fluoro rubber. The combination pad has both the metric and the English, and the standard jb982-77 sets the combination of the metal pad and rubber. Composite Grommets for pipe fittings and screw thread seal, it is generally used with pipe connector of cutting sleeve type, used to block oil mouth, it is mainly used for static seal of hydraulic valve pipe thread connection, France and Britain, the United States standard inch thread, the German standard metric thread joint static seal, etc. The combined Grommets can be divided into type A and type B according to the structure form; According to the different bag glue can be divided into whole package, half package.

The composite Grommets is widely used in the oil - medium pipeline system for welding, sleeve, expansion pipe joint, screw plug and mechanical device of the end face static seal.

2. Structural dimensions and parameters of composite pad

Combination cushion structure schematic combination mat, d = Φ 8 said nominal diameter of 8 mm. Tolerance of diameter: 0.12-0.20. Allows for working pressure of 400 kg/cm2 (39.2 MPa), working temperature between 25-80 ℃.

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