Terms of teeth Top land(齿顶面) Tooth face(齿面) Bottom land(齿槽底面) Fillet radius (齿根圆弧半径) Introduction to Engineering
11 Introduction to Engineering Terms of teeth Top land（齿顶面） Tooth face（齿面） Bottom land（齿槽底面） Fillet radius （齿根圆弧半径）
Tooth Thickness and Space Tooth thickness(齿厚)：The thickness of a tooth is measured along the gear's pitch circle. Tooth thickness Tooth space(齿间距)：The spacing Tooth space between adjacent teeth is measured along the gear's pitch circle. The tooth space should be slightly larger than the tooth thickness to prevent the teeth from binding against one another But not too large,the free play could cause undesirable rattle(嘎吱声)，vibration,and speed fluctuations(波动， 起伏) Introduction to Engineering
12 Introduction to Engineering Tooth Thickness and Space Tooth thickness（齿厚）: The thickness of a tooth is measured along the gear’s pitch circle. Tooth space（齿间距）: The spacing between adjacent teeth is measured along the gear’s pitch circle. The tooth space should be slightly larger than the tooth thickness to prevent the teeth from binding against one another But not too large, the free play could cause undesirable rattle（嘎吱声）, vibration, and speed fluctuations（波动， 起伏） Tooth thickness Tooth space
Module(模数) In the SI,the spacing between teeth is measured by a quantity called the module m. 2r m N Where N is the number of teeth on the gear. The module has the units of millimeters Compatible pinion and gear must have the same value of m(otherwise the gearset will bind as the shafts begin to rotate) Introduction to Engineering
13 Introduction to Engineering Module（模数） In the SI, the spacing between teeth is measured by a quantity called the module m. N r m 2 Where N is the number of teeth on the gear. The module has the units of millimeters Compatible pinion and gear must have the same value of m (otherwise the gearset will bind as the shafts begin to rotate)
Shape of Teeth >Any complementary(互补)shape are capable of transmitting rotation >In the past,wooden pegs serve as teeth in water-and wind-powered mills.It did not provide smooth and efficient operation. Arbitrarily shaped gear teeth,generally can not guarantee uniform and steady speed result in noise,vibration,wear, and inefficiency Introduction to Engineering
14 Introduction to Engineering Shape of Teeth Any complementary（互补）shape are capable of transmitting rotation In the past, wooden pegs serve as teeth in water- and wind-powered mills. It did not provide smooth and efficient operation. Arbitrarily shaped gear teeth, generally can not guarantee uniform and steady speed result in noise, vibration, wear, and inefficiency