单级齿轮副的传动比(转速比)即使在正齿轮低速回转时也不得超过1/7,一般为1/5左右,也可达1/6。此外,对伞齿轮和人字齿轮,传动比的极限如表2-6所示。为了减小整个机器的外形尺寸,龆轮的齿图表2-34为每级传动比(上式中的1/B 及1/C)已知时,假设 Z_1而求 Z_2(或代入 Z_2以求Z_4) 用的图表。(?)[例题2-34] 当龆轮齿数 Z_1=17,传动比 i=1/4. 8时,大齿轮的齿数 Z_2为多少?解:Z_1轴上的17和 i 轴上的1/4. 8的连线与 Z_2相交,交点读数83即为所求的 Z_2 The gear ratio (speed ratio) of the single-stage gear pair must not exceed 1/7 even at low speed rotation of the spur gear, generally about 1/5, up to 1/6. In addition, for bevel gears and herringbone gears, the transmission ratio limits are shown in Table 2-6. To reduce the overall size of the machine, Figure 2-34 shows the pinion of a pinion. When each gear ratio (1 / B and 1 / C in the above formula) is known, assume Z_1 and find Z_2 (or substitute Z_2 Z_4) with the chart. (?) [Example 2-34] What is the number of gear teeth Z_2 when the number of pinion Z_1 = 17 and the gear ratio i = 1/4. 8? Solution: The ratio of 17 on the Z_1 axis and 1 / 4. The intersection of 8 and the intersection of Z_2, the intersection of the intersection of reading and the intersection of 83 and the intersection of seeking and Z2