二、液压用油及其选择 (一)对液压用油的要求[1][29] 1.具有适宜的粘度和良好的粘温特性。在工作温度变化范围内,粘度变化要最小,粘度太大,阻力大,磨损增加,灵敏度降低;粘度太小,则泄漏严重,容积效率降低,功率损失增加。根据现有资料,国外精密机床所用液压油的粘度指数都在90以上(见表1—10)。 Second, hydraulic oil and its choice (a) of the hydraulic oil requirements [1] [29] 1. Has a suitable viscosity and good viscosity temperature characteristics. In the range of working temperature changes, the viscosity change is the smallest, the viscosity is too large, the resistance is large, the wear is increased, and the sensitivity is decreased; if the viscosity is too small, the leakage is serious, the volumetric efficiency is reduced, and the power loss is increased. According to available data, the viscosity index of hydraulic oil used in foreign precision machine tools is above 90 (see Table 1-10).