Development of Fluorine Rubber Exposed Skeleton Oil Seal

Oil seal is a kind of rubber sealing product widely used in construction machinery, automobile, aviation and other fields. It has a flexible lip and a metal skeleton support inside. It applies radial force to the shaft by the sealing edge to seal the lubricating oil. The quality of the oil seal is directly related to whether the equipment can operate normally. With the rapid development of the automobile manufacturing industry, the use conditions of oil seals are becoming more and more severe, and the use temperature is also getting higher and higher. The traditional nitrile rubber can no longer meet the use requirements in many aspects. Fluorine rubber has excellent high temperature resistance and oil resistance, and is an ideal material for manufacturing high temperature oil seals. 1 Product structure The structure of the exposed skeleton oil seal we designed is shown in Figure 1. In the past, the oil seal design was mostly reverse auxiliary lip (as shown in Figure 2). Foreign studies have found that the reverse auxiliary lip will increase the temperature rise of the main lip11. C, thus greatly reducing the service life of the oil seal. In the experiment, it was found that the radial force of the old-fashioned reverse auxiliary lip was greatly increased, which intensified the frictional heat generation, resulting in the temperature rise of the main lip. The oil seal we designed adopts a new type of auxiliary lip structure in the same direction. The auxiliary lip is thin and soft, and the radial force on the shaft is small, and the dustproof effect is also very good in actual use. Table 1 lists the difference in radial force between the reverse auxiliary lip oil seal and the exposed skeleton oil seal before and after the auxiliary lip is removed. 2 Compound formulation design 2.1 Experimental raw materials Domestic 26B fluororubber, Shanghai 3F Company; Bisphenol AF, Shanghai Sanaisi Reagent Co., Ltd.; BPP (benzyltriphenylphosphonium chloride), Shanghai Sanaisi Reagent Co., Ltd.; 3}≠ Vulcanizing Agent, China Jinhua Biochemical Factory; Calcium Hydroxide, China Pharmaceutical Group Shanghai Chemical Reagent Co., Ltd.; Calcium Fluoride, Shanghai Sanaisi Reagent Co., Ltd.; Barium Sulfate, Beijing Hongxing Chemical Factory; Adhesive ap133, Shanghai Lord Company; other materials are commercially available industrial grades. 2.2 The commonly used vulcanizing agent for fluororubber in the vulcanization system is 3}≠ vulcanizing agent. This vulcanization system has a fast vulcanization rate. It has been reported in China that the 3}≠ vulcanizing system is used to produce fluororubber oil seals, but the compression set of this vulcanization system is too large. , is not conducive to sealing. In recent years, fluororubber has begun to state that the comprehensive performance of spray carbon black is slightly better than that of other fillers. 3 Production process 3.1 Rubber compound mixing The XK160 open mill is used to mix the rubber material. Mix magnesium oxide, carbon black and wear-resistant fillers evenly and add them slowly. Finally, add vulcanizing agent and accelerator. The rubber compound is thinned for 8 times and then sliced ​​and cut into strips. 3.2 Skeleton treatment Due to the small bonding area between the exposed skeleton oil seal compound and the skeleton, the metal skeleton can be sprayed to increase the bonding area to improve the bonding strength. During the sandblasting process, pay attention to control the sand grains generally less than 1.5mm, and the pressure is 0.1-0.2MPa. If the sand grains are too large and the pressure is too high, it is easy to cause the skeleton to deform during the sandblasting process, making the product size unstable. The adhesive is ap133 adhesive from Shanghai Lord Company. The production process is: sandblasting, gasoline cleaning, natural drying, applying adhesive, drying for use; after gasoline cleaning and drying, ap133 glue from Shanghai Lord should be applied immediately to avoid rusting of the skeleton. 3.3 Turning of the skeleton The outer circumference of the skeleton is left with a margin, which can not only avoid the deformation of the skeleton during the sandblasting and vulcanization process, but also turn off the corroded part of the outer side during the second-stage vulcanization process to ensure the appearance of the product. 3.4 Cutting lip The shrinkage rate of fluororubber varies widely, and the main lip of the exposed skeleton oil seal adopts the full-cutting lip technology. The size of the main lip is controlled by cutting the lip of the oil seal trimmer, which avoids the large change of the size of the main lip due to some unstable factors. 3.5 Process flow The production process of the oil seal with exposed skeleton is as follows: rubber compounding, rubber strip preparation, vulcanization, deburring, turning skeleton, cutting lip, El, spring installation, rust prevention treatment, packaging and storage + skeleton manufacturing, sandblasting adhesive—J4 Conclusion The fluororubber exposed skeleton oil seal made of bisphenol AF vulcanization system has excellent performance, can be used under high temperature and high speed conditions, and can completely replace imported products https://www.orksealing.com/