[机械工程专业英语教程第2版Lesson39.ppt

《电子信息工程专业英语教程》 Lesson 39 Gear Manufacturing Methods Terminology Text tour Terminology 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） Hob 滚刀 Worm 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 Broach 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。 Dressing Dressing 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。 Text tour Gear 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。 Gear 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。 For 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。 Gear 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 r