Lesson 29 Gear Manufacturing Methods 机械专业专业英语教学用书.pptVIP

Lesson 29 Gear Manufacturing Methods Gear Planing（刨齿） The shape of the space between gear teeth is complex and varies with the number of teeth on the gear as well as tooth module（模数），so most gear manufacturing methods generate the tooth flank (齿腹) instead of forming（采用展成法加工齿面而不是采用成形法加工）. Lesson 29 Gear Manufacturing Methods Gear planing uses a reciprocating rack（往复运动的齿条刀）, stroking（击、打、切）in the direction of the helix（螺旋） on a gear with a gradual generation of form as the rack effectively rolls round the gear blank (齿轮毛坯) （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）. …… Lesson 29 Gear Manufacturing Methods ……The rack is relieved out of contact（脱离接触）for the return stroke as in normal shaping or planing（与普通的刨削加工相同）. It has the great advantage that the cutting tool is a simple rack with (nearly) straight sided teeth which can easily be ground accurately(刀具为具有直线齿形或者接近与直线齿形的齿条，其齿面易于进行精确磨削加工). …… Lesson 29 Gear Manufacturing Methods ……This method is little used (几乎不用) for high production because it is relatively slow in operation due to the high tool and slide mass(由于刀具和滑枕的质量较大)；for jobbing（重复性很小的工作）purposes the slow stroking rate does not matter and low tool costs give an advantage where unusual sizes or profile modifications are required. （对于单件或者少量的齿轮加工而言，缓慢的行程速度带来的影响不大，而且较低的刀具成本对于那些特殊规格和需要进行齿廓修形的齿轮来说则是一个有利的条件） Lesson 29 Gear Manufacturing Methods Gear Shaping（插齿） Gear shaping is inherently (内在的,故有的) similar to gear planing（刨齿加工）but uses a circular cutter （圆形刀具）instead of a rack(齿条刀) and the resulting reduction in the reciprocating inertia （运动惯性）allows much higher stroking speeds（行程速度）；modern gear shapers（插齿机）cutting car gears can run at 2000 cutting strokes per minute. The shape of the cutter is roughly the same as an involute gear（渐开线齿轮）but the tips of the teeth are rounded. Lesson 29 Gear Manufacturing Methods The generating drive between cutter and workpiece does not involve a rack or leadscrew since only circular motion is involved（由于刀具与工件之间的展成运动只包含圆周运动，因此不需要齿条或者丝杠）. The tool