英语翻译The crankshaft,regarded as the"backbone" of the engine,a

英语翻译
The crankshaft,regarded as the"backbone" of the engine,as shown in figure 2-6,serves to change the reciprocating motion of the piston into rotary motion and handles the entire power output.The periodic gas and inertia forces taken by the crankshaft may cause it ti suffer wear and bending and tensional strains.the crankshaft therefore must be adequately strong and wear-resistant.So the crankshaft is either forged from high quality steel or cast in a high-strong iron.The crankshaft shown in Figure 2-6 is actually made up of various pats such as main bearing journals,rod journal,crank arm,bearing,counter balanced weight and fiywheel end.the crankshaft revolves in bearings located in the engine crankcase ,but the number of bearings used usually depends on the number of cylinders in the engine,and the design of the engine.Mechanically,a crankshaft whiteout special balanced weight would have severe vibration when revolving.In order to reduce or eliminate such vibration,it must be provided with counter balanced weights that extend radically from the crankshaft are balanced and vibration is reduced.The rod journals are bored hollow in order to reduce the crankshaft inertia.Drilled diagonally through the crank arms are oil holes to supply oil to the rod journals.

曲轴,被认为是发动机的中枢,如图2-6所示,用于将（活塞的）往复运动转变为（车轮的）旋转运动并传递全部的功率输出.周期性的气体压力及惯性力会造成曲轴承受疲劳磨损、弯曲应变及拉伸应变；因此,曲轴必须是高强度且抗疲劳的.所以,曲轴或由碳素钢铸造而成,或由高强度铸铁（如球墨铸铁）浇铸而成.图2-6所示的曲轴由多种零件构成,如主轴轴颈,连杆轴颈,曲柄,轴承,平衡重和飞轮.曲轴绕固定在曲轴箱内的主轴旋转,轴承数一般取决于发动机气缸数及发动机的设计（如全支承曲轴或者非全支承曲轴）.机械运动中,无平衡重的曲轴在转动中将承受极大的震动.为降低或消除震动,曲轴必须有平衡重,（平衡重）位于曲柄反方向的外延部分,以平衡并减弱震动对其的影响.连杆轴颈上钻孔以便降低曲轴惯性力.曲柄上分布的对角孔为油孔,用于润滑连杆轴颈.
注：括号内容是为便于理解而进行的注释,并非原文内容.