英语翻译As a machine component a shaft is commonly a cylindrical

英语翻译
As a machine component a shaft is commonly a cylindrical bar that supports and rotates with devices for receiving and delivering rotary motion and torque.The crankshaft of a reciprocating engine receives its rotary motion from each of the cranks,via the pistons and connecting rod (the slider-crank mechanisms),and delivers it by means of couplings,gears,chains,or belts to the transmission,camshaft,pumps,and other devices.The camshaft,driven by a gear or chain from the crankshaft,has only one receiver or input,but each cam on the shaft delivers rotary motion to the valve-actuating mechanisms.An axle is usually defined as a stationary cylindrical member on which wheels and pulleys can rotate,but the rotating shafts that drive the rear wheels of an automobile are also called axles,no doubt a carryover from horse-and-buggy days.It is common practice to speak of short shafts on machines as spindles,especially tool-carrying or work-carrying shafts on machine tools.In operation,shafts are subjected to shearing stress; the maximum shearing stress is proportional to the polar moment of the cross section.In designing a shaft,it is necessary to insure that,under any conditions,the shaft’s maximum shearing stress must below (or at lest equal to) the allowed shearing stress.

作为机器组件,轴、通常是一个圆棒,用于设备的支持和旋转,接收和传送旋转运动和扭矩.往复式发动机曲轴接收其从每个曲柄的旋转运动,通过活塞和连杆（曲柄滑块机制）,并由联轴器,齿轮,链条,或传输皮带,凸轮轴,泵和其他设备传递.
凸轮轴,在齿轮或曲轴链的带动下,只能有一个接收器或输入,但这个轴上的每个凸轮提供旋转运动的阀门驱动机构.车轴通常被定义为一个固定的圆柱形构件,在其上面的轮子和滑轮可以旋转,但旋转轴驱动汽车的后轮也被称为车轴.
通用的规则来说,机器上的短轴做为心轴,尤其是指携带工具或带载工作.在操作中,轴受到剪应力,最大剪应力是正比于横截面极矩.在设计一个轴,这是必要保证的,在任何条件下,轴的最大剪应力必须低于（或至少等于）允许的剪切应力.