Type of common cylinder gasket
Common cylinder gaskets include asbestos (non asbestos) rubber composite gasket, metal clad (copper clad iron clad) gasket, composite coating gasket, metal composite gasket and metal rubber ring gasket.
According to the characteristics of different raw materials, the cylinder gasket can be divided into copper plate cylinder gasket, composite plate cylinder gasket and asbestos cylinder gasket. Apply Viton DAI-EL on the surface of stainless steel plate. DAI-EL has heat resistance, can withstand repeated heating and cooling, and excellent oil resistance and sealing.
Metal rubber ring gasket
The metal rubber ring gasket is structurally divided into single-layer integral rubber ring gasket, single-layer riveted rubber ring gasket and multi-layer rubber ring gasket. Integral vulcanization molding refers to one-time vulcanization of oil-water hole rubber ring by injection or molding. This method is used for single-layer integrated rubber ring gasket.
The combination method of rubber ring vulcanization molding and metal skeleton refers to the method of making oil and water hole rubber rings with or without skeleton respectively by injection or molding, and then connecting with metal skeleton. This method is used for single-layer riveted rubber ring gasket and multi-layer rubber ring gasket.
Selection of rubber ring material
Considering that the engine works in the environment of high temperature, high pressure, high explosion rate, high power, lubricating oil, antifreeze, gas and other media, the sealing materials of the engine cylinder gasket are mainly fluorine rubber and silicon rubber.
Fluorine rubber (FKM) is a kind of organic elastomer formed by copolymerization of fluorine-containing monomers. In addition to excellent heat resistance, medium resistance and good physical and mechanical properties, it also has low compression set, good elasticity and long service life. Fluorine rubber has excellent heat resistance and oil resistance, and can be used as the material of cylinder gasket. The disadvantage is poor cold resistance, and the working temperature range is - 30 ℃~+230 ℃.
The curing system of fluororubber includes amine curing, bisphenol (polyol) curing and peroxide curing. Amine vulcanization is characterized by large compression set, while bisphenol (polyol) vulcanization is characterized by low compression set but slightly poor water resistance. The peroxide vulcanization is characterized by excellent water resistance and resistance to some amine compounds in lubricating oil without cracking. Its comprehensive performance is relatively balanced, but the price is expensive.
Silicone rubber (VMQ) is a special rubber with silicon and oxygen atoms in the main chain. It has excellent high and low temperature resistance, but ordinary silicone rubber has low mechanical strength, oil resistance and solvent resistance. Operating temperature range: - 60 ℃~+230 ℃.
1.Material selection of single-layer integrated rubber ring gasket
The single-layer integrated rubber ring material can be peroxide vulcanized fluororubber, bisphenol vulcanized fluororubber and oil-resistant silicone.
Single-layer integrated rubber ring gasket can be produced by injection and molding.
Compared with molding, the injection machine has the following advantages:
① The formed products have dense texture, precise size and good physical and chemical properties;
② Short curing time and high production efficiency;
③ High utilization rate of raw materials and low production cost;
④ Small floor area, which can save production space;
⑤ Simple operation, low labor intensity and high degree of automation.
However, due to the complex structure and large investment of the injection molding machine and its mold, the mechanical processing and maintenance need a high level of technology, which is suitable for large quantities of products. In addition, in order to reduce the waste of rubber, rubber injection machine with cold runner can be used.
2.Selection of materials for single-layer riveted rubber ring gasket and multi-layer rubber ring gasket
The oil hole material of single-layer riveted rubber ring gasket and multi-layer rubber ring gasket can be bisphenol vulcanized fluororubber or oil-resistant silicone, while peroxide vulcanized fluororubber is expensive and cannot be selected.
Water hole material can be ordinary silicone rubber or oil-resistant silicone rubber, while peroxide vulcanized fluororubber is expensive and cannot be used.
summary
The engine works in the environment of high temperature, high pressure, high explosion rate, high power, lubricating oil, antifreeze, gas and other media, and requires high oil and water hole materials. The metal rubber gasket oil and water hole materials are mainly fluorine rubber and silicon rubber to meet the requirements. Different types of rubber can be selected for metal rubber ring gaskets with different structures. The single-layer integrated rubber ring material can be peroxide vulcanized fluororubber, bisphenol vulcanized fluororubber and oil-resistant silicone. The oil hole material of single-layer riveted rubber ring gasket and multi-layer rubber ring gasket can be bisphenol vulcanized fluororubber or oil-resistant silicone, while peroxide vulcanized fluororubber is expensive and cannot be selected. The water hole material can be ordinary silicone rubber or oil-resistant silicone rubber. Peroxide vulcanized fluororubber is expensive and cannot be used.
