机械工程专业英语课件 -1精品.ppt

Torsional defection can affect the accuracy of a cam or gear driven mechanism. Furthermore, the greater the flexibility––either lateral or torsional—the lower the corresponding critical speed.[4] 4. critical speed 意为“临界转速”。全句可译为： 此外，柔性（横向的或扭转的）越大，则相应的临界转速就越低。 Sometimes members like gears and cams are made integral with the shaft, but more often such members (which also include pulleys, sprockets, etc. ) are made separately and then mounted onto the shaft. The portion of the mounted member in contact with the shaft is the hub. Attachment of the hub to the shaft is made in a variety of ways. A gear can be gripped axially between a shoulder on the shaft and a spacer, with torque being transmitted through a key.[5] The grooves in the shaft and hub into which the key fits are called keyways. 5. shoulder on the shaft 意为“轴肩”。全句可译为： 一个齿轮可以用轴肩和挡圈进行轴向固定，并通过键来传递扭矩。 《机械工程专业英语教程》 * * A simpler attachment for transmitting relatively light loads is provided by pins. Pins provide a relatively inexpensive means of transmitting both axial and circumferential loads. 更简单的用来传递相对较轻载荷的连接的是销。销提供了一种能同时传递轴向和周向载荷的较便宜的手段。 An excellent and inexpensive method of axially positioning and retaining hubs and bearings onto shafts is by means of retaining rings, commonly called snap rings. Shaft snap rings require grooves that weaken the shaft, but this is no disadvantage if they are located where stresses are low. 一种极好的又很便宜的使轮毂和轴承在轴上轴向定位并固定的方法是用定位环，通常叫卡环。轴卡环需要（在轴上）开槽，这会使轴的强度降低，但如果槽开在应力较小的地方这也不算什么缺点。 Perhaps the simplest of all hub-to-shaft attachments is by means of an interference fit[6] (hub bore is slightly smaller than shaft diameter, with assembly being made with a press, or by thermally expanding the hub–––sometimes also contracting the shaft, as with dry ice–––prior to making a quick assembly before the temperatures equalize). 6. interference fit 意为“过盈配合”。全句可译为： 借助于过盈配合来实现的联接可能是轮毂与轴之间的最简单的固定方式。毂孔比轴径稍小，用压装法或使毂热膨胀——有时也用干冰让轴冷缩——在它们温度相同之前快速装配。 * 《机械工程专业英语教程》 * The strongest provision for torqu