齿轮机构-----中英文翻译、外文文献翻译.doc

Gear mechanisms are used for transmitting motion and power from one shaft to another by means of the positive contact of successively engaging teeth. In about 2,600B.C., Chinese are known to have used a chariot incorporating a complex series of gears like those illustrated in Fig.2.7. Aristotle, in the fourth century B .C .wrote of gears as if they were commonplace. In the fifteenth century A.D., Leonardo da Vinci designed a multitude of devices incorporating many kinds of gears. In comparison with belt and chain drives ,gear drives are more compact ,can operate at high speeds, and can be used where precise timing is desired. The transmission efficiency of gears is as high as 98 percent. On the other hand, gears are usually more costly and require more attention to lubrication, cleanliness, shaft alignment, etc., and usually operate in a closed case with provision for proper lubrication.
Gear mechanisms can be divided into planar gear mechanisms and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and power between parallel shafts ,and spatial gear mechanisms between nonparallel shafts.
Types of gears
(1) Spur gears. The spur gear has a cylindrical pitch surface and has straight teeth parallel to its axis as shown in Fig. 2.8. They are used to transmit motion and power between parallel shafts. The tooth surfaces of spur gears contact on a straight line parallel to the axes of gears. This implies that tooth profiles go into and out of contact along the whole facewidth at the same time. This will therefore result in th

齿轮机构用来传递运动和动力，通过连续啮合轮齿的正确接触，从一根轴传动到另一根轴。大约公元前2600年，中国人就能够使用一系列战车而闻名复杂的齿轮机构而构成的。公元前4世纪，亚里士多德写的齿轮好象推动的是平凡的。在公元15世纪，Leonardo da Vinci 设计了能与许多种类的齿轮枢结合的大量装置。与皮带和链传动相比较，齿轮传动装置更加紧凑，能高速运行，也能够被运用在要求准确定时的场合。齿轮传动的传动效率高达98％。另一方面，齿轮传动机构成本高，而且要求注意润滑、清洁度、轴的对中等等，经常用在提供准确箱体润滑的闭式情况下。
齿轮机构能被分为平面齿轮机构和空间齿轮机构。平面齿轮机构被用于传递运动和动力，而平行轴间的运动和动力空间齿轮机构用于传递不平行轴间的运动和动力。