机械工程专业英语教程第2版Lesson 39.ppt

Lesson 39 Gear Manufacturing MethodsTerminologyText tour 12/21/20221机械工程专业英语教程Terminology12/21/20222机械工程专业英语教程Annular Shaped like or forming a ring.环形的，轮状的：形状像环或形成环状。Annular gear 内齿轮,齿圈（也称为internal gear）机械工程专业英语教程12/21/2022Helical gear 斜齿轮 3Hob 滚刀12/21/2022机械工程专业英语教程4Worm 蜗杆Worm gear 1.A gear consisting of a spirally threaded shaft and a wheel with marginal teeth that mesh into it蜗轮蜗杆副2.The toothed wheel of this gear,a worm wheel蜗轮12/21/2022机械工程专业英语教程5Broach 拉刀Swarf Fine metallic filings or shavings removed by a cutting tool.小铁屑：用锉或剃等加工方法去除的细小金属屑。12/21/2022机械工程专业英语教程6DressingDressing is the process of conditioning worn grains on the surface of a grinding wheel by producing sharp new edges on grains so that they can cut more efficiently.砂轮修整：使砂轮表面磨钝的磨粒上产生新的锋利的切削刃，使其能够更有效地进行切削工作。12/21/2022机械工程专业英语教程7Gear planing uses a reciprocating rack,stroking in the direction of the helix on a gear with a gradual generation of form as the rack effectively rolls round the gear blank.The rack is relieved out of contact for the return stroke as in normal shaping or planing.刨齿采用往复运动的齿条刀，当齿条刀绕齿轮坯料滚切并沿其螺旋线方向运动时，齿形就会被逐渐展成。与普通的刨削加工相同，在回程中齿条刀与齿轮脱离接触。机械工程专业英语教程12/21/2022Text tour8Gear shaping is inherently similar to gear planing but uses a circular cutter instead of a rack and the resulting reduction in the reciprocating inertia allows much higher stroking speeds.插齿加工在本质上与刨齿加工类似，只是采用了圆形刀具来取代齿条刀。机械工程专业英语教程12/21/20229For helical gears,a helical guide is required to impose a rotational motion on the stroking motion;such helical guides cannot be produced easily or cheaply so the method is only suitable for long runs with helical gears since special cutters and guides must be manufactured for each different helix angle.加工斜齿轮时，需要有一个能够产生绕插齿运动行程本身旋转的螺旋导轨。这种螺旋导轨不易制造，或者说其制造成本较高。由于对每一种不同螺旋角的齿轮，应该制造不同参数的插齿刀和螺旋导轨，因此这种方法仅适用于斜齿轮的大批量加工。机械工程专业英语教程12/21/202210Gear hobbing,the most used metal cutting method,uses the rack generating principle but avoids slow reciprocation by mounting many“racks”on a rotating cutter.The“racks”are displaced axially to form a gashed worm.Metal removal rates are high since no reciprocation of hob or workpiece is required.滚齿是最常见的金属切削方法。它采用齿条展成原理，但是通过安装在旋转刀具上的许多“齿条”来避免缓慢的往复运动。这些“齿条”轴向排布，形成了有缝的蜗杆。由于滚刀和工件均不作往复运动，因此滚齿加工时的金属切削率很高。机械工程专业英语教程12/21/20221112/21/2022机械工程专业英语教程12A gear shaving cutter looks like a gear which has extra clearance at the root(for swarf and coolant removal)and whose tooth flanks have been grooved to give cutting edges.It is run in mesh with the rough gear with crossed axes so that there is in theory point contact with a relative velocity along the teeth giving scraping action.剃齿刀形如齿轮，在刀齿的根部有一附加的凹槽(用于排除切屑和冷却液)，在齿面上开许多小槽以形成切削刃。剃齿刀与经过粗加工的齿轮成交错轴啮合传动。这样在理论上沿着轮齿有一个具有相对速度的点接触，从而产生刮削作用。13机械工程专业英语教程12/21/202214机械工程专业英语教程12/21/2022Gear grinding is extremely important because it is the main way hardened gears are machined.When high accuracy is required it is not sufficient to pre-correct for heat treatmentdistortion and grinding is then necessary.磨齿是非常重要的，因为它是加工淬硬齿轮的主要方法。当对于热处理变形的预先校正达不到齿轮所要求的高精度时，就必须采用磨削加工。15机械工程专业英语教程12/21/2022The fastest gear grinding method uses the same principle as gear hobbing but replaces a gashed and relieved worm by a grinding wheel which is a rack in section.Only single start worms are cut on the wheel but gear rotation speeds are high,100 rpm typically,so it is difficult to design the drive system to give accuracy and rigidity.最快的磨齿齿方法采用与滚齿相同的原理，但是使用截面为齿条的砂轮来取代有排屑槽的蜗杆形滚齿刀。砂轮只能被切削成单头蜗杆形，由于齿轮的转速通常高达100 r/min，因此设计具有所需要的精度和刚度的驱动系统是困难的。16机械工程专业英语教程12/21/2022