专业英语 课件概要1.ppt

张贤朋8061211139 张广伟8061211118 陈亚东8061211124 马 新8061211115 Lesson 8 Rolling Bearings Rolling bearings can carry radial, thrust or combination of the two loads. Accordingly, most rolling bearings are categorized in one of the three groups: radial bearings for carrying loads that are primarily radial, thrust bearings for supporting loads that are primarily axial, and angular contact bearings or tapered roller bearings for carrying combined radial and axial loads. categorized: 把······归为一类 radial:径向的 thrust:轴向的 angular contact bearings:角接触轴承 tapered roller bearings:圆锥滚子轴承 Figure 8.1a shows a common single-row, deep groove ball bearing. The bearing consists of an inner ring, an outer ring, the balls and the separator. To increase the contact area and. hence permit larger loads to be carried, the balls run in curvilinear grooves in the rings called raceway deep groove ball bearing：深沟球轴承 separator：支架 curvilinear：弧形 consists of：由·······组成 The radius of the raceway is very little larger than the radius of the ball. This type of bearing can stand a radial load as well as some thrust load. Some other types of rolling bearings are shown in Figs. 8. 1b, 8. lc and 8. 1d. The concern of a machine designer with ball and roller bearings is fivefold as follows: (a) life in relation to load; (b) stiffness, i. e. deflections under load; (c) friction; (d) wear; (e) noise. For moderate loads and speeds the correct selection of a standard bearing on the basis of load rating will usually secure satisfactory performance. fivefold：五倍的，五重的 stiffness：刚性，刚度，稳定性 deflections：偏差，偏移，弯曲，挠度 friction：摩擦 wear：磨损，磨蚀，消耗，耗损 satisfactory：令人满意的; 符合要求的 The deflection of the bearing elements will become important where loads are high, although this is usually of less magnitude than that of the shafts or other components associated with the bearing. Where speeds are high special cooling arrangements be