机械类中英文翻译.doc

英文原文 Cams Various motions can be produced by the action of a cam against a follower.Mamy timing devices are operated by can action.The purpose of andy cam is to produce a displacement of its follower;a secondary follower is often .used to produce additional displacement in another location.The most popular type is the plate cam.The cylindrical type is used to transmit linear motion to a follower as the cam rotates.Three-dimensional cam are sometimes used;these provide some unusual follower motions,but also make follower design difficult.The camshaft in the automotive engine illustrates a simple but important application of a late cam.The cam assemblies in automatic record players illustrate a somewhat more complex application. Cam profiles are accurately constructed by either praphical or mathematical methods.The transitiom from development drawings to working (shop) drawing can be made in several ways: 1.Make a full-scale template.This is desirable from the manufacturing standpoint,but it will not guarantee accurate cam profiles. 2.Use radial dimensions.This is fairly accurate,but sometimes produces layout problems in the shop. 3.Use coordinate dimensioning.This procedure will ensure accuracy. In selecring one of these methods,one should consider the function of the cam in terms of desired preciseness. Because the cam work outline already determined, therefore the cam structural design mainly was determines the curve outline axial thickness and the cam and the drive shaft connection way. When the work load compares the hour, curve outline axial thickness generally takes for the outline curve biggest radius of vector 1,/10 ～/5; Regarding a stress bigger important situation, must with carry on the design according to the cam contour surface from the contact intensity. When determination cam and drive shaft joint way, should synthesize the consideration cam the assembling and dismantling, the adjustment and firmly grades the question. Regarding implementing agency