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油封也用于含杂质的水的密封,由于水的粘度低,并且对旋转轴有腐蚀性,故油封对其密封的工作性能是很难估价的。确定水对油封密封性能的试验结果表明,油封的摩擦特性是干摩擦,是不稳定的,这是由于油封唇缘与轴表面间的流体膜损坏的原因。显然,适当地选择油封唇材料,加少量的油或表面活性剂能使这种摩擦性能变得稳定。在密封条件下,有蒸汽从唇/轴的界面喷出,喷出的蒸汽凝结在唇的空气一侧,而该侧的空间是密闭的。这种凝结表示有泄漏现象。轴表面的机械加工纹路对这种喷出作用的影响是显著的。术语: a—三角槽深度,厘米。 b—油封边缘接触宽度,厘米。 B—三角槽宽度,厘米。 D—轴外径,厘米。 f_d—摩擦系数。 f_d—干态摩擦系数。 f_(d·max)—干态最大摩擦系数。 f_(d·min)—干态最小摩擦系数。 G—无因次流动性参数,由ZVb/Pr确定。 n—三角槽数量。 Pr—唇总接触负荷,N。 Qv—三角槽中流速量,厘米~3/分。 V—密封面上滑动速度,厘米/秒。 Z—工作温度下的粘度,帕·秒。α—三角槽角度,度。β—三角槽线角度,度。λ—三角槽节距,厘米。λ_n—三角槽法向节距,厘米。θ_1—密闭空间温度,℃。θ_2—丙烯酸树脂板表面温度,℃。θ_3—丙烯酸树脂板表面温度,℃。θ_4—丙烯酸树脂板表面温度,℃。θ_5—丙烯酸树脂板表面温度,℃。Φ—密封性能常数,由f·G~(-1/3)确定。
The oil seal is also used for the sealing of water with impurities. Due to the low viscosity of water and the corrosiveness to the rotating shaft, it is hard to evaluate the sealing performance of the oil seal. Test results to determine the sealing performance of the seal on the oil seal indicate that the friction characteristic of the seal is dry friction and is unstable due to the damage of the fluid film between the seal lip and the shaft surface. Obviously, the proper choice of oil lip material, with a small amount of oil or surfactant to make this frictional properties become stable. Under sealed conditions, steam is ejected from the lip / shaft interface and the ejected vapor condenses on the air side of the lip and the space on that side is hermetically sealed. This condensation indicates a leak. The effect of this squirting action on the machining of the shaft surface is significant. Terms: a - triangular groove depth, cm. b-oil seal edge contact width, cm. B-triangular groove width, cm. D-axis diameter, cm. f_d - coefficient of friction. f_d-dry friction coefficient. f_ (d · max) - maximum dry friction coefficient. f_ (d · min) - Minimum dry friction coefficient. G-dimensionless mobility parameter, determined by ZVb / Pr. n-triangle slot number. Pr-lip total contact load, N. Qv-triangular groove in the flow rate, cm ~ 3 / min. V-sliding speed on the sealing surface, in cm / s. Z - viscosity at operating temperature, Pascal seconds. Alpha groove angle, degree. β-trough groove angle, degree. λ-triangular slot pitch, cm. λ_n-triangular groove normal pitch, cm. θ_1-confined space temperature, ℃. θ_2-acrylic plate surface temperature, ℃. θ_3-acrylic plate surface temperature, ℃. θ_4-acrylic plate surface temperature, ℃. θ_5-acrylic plate surface temperature, ℃. Φ-seal performance constant, determined by f · G ~ (-1/3).