AGMA 91FTM12-1991 pdf free.The Combined Mesh Stiffness Characteristics of Straight and Spiral Bevel Gears.
As an example, three gear pairs are given; 1.0” (ace width of the straight and the spiral bevel gear, and 1.5” face width of the spiral bevel gear. In all case, both pinion and gear have 25 teeth, and tooth has a 20 degree pressure angle. The 1.0 face width of the bevel gears have a 5.482 diameiral pitch, and 1.5” face width of the spiral bevel gear has a 5.088 diametral pitch.
Fig. 8 shows the combined stiffness of the straight bevel gear pair which has 1.7 contact ratio. The stiffness does not vary significantly within one pair region or two pair tegion but the abrupt change occurs between the two regions. The trend of this resuk is very similar compared with the result of spur gear pair which was evaluated by 3. Chakraborty and N. G. Hunashikatti (1]. This is also an expected result for the straight bevel gear pair because the difference between straight bevel and spur gear pair is only the angle of shaft axis. Fig. 9 and 10 shows the combined mesh stiffness of the spiral bevel gear pair with 35 degree spiral angle and the different face widths, 1.0” and IS’. FIg. 9 shows that the stiffness varies within the three pair contact region and the abrupt change occurs at the transition to the two tooth pair region. but the amount of the change is smaller compared to the straight bevel gearpair. InthecaseofFig.9, the face width is 1.0(in)and the total contact ratio is 193. Thus, the mnnber of tooth pairs in contact is two or three on a time basis. In the case of Fig. 10, the face width is 1.5” and the total contact ratio is 3.43. Therefore, the three or four tooth pairs contact on a time base, and so one tooth pair region does not appear in Fig. 9 and 10. Also, the variation of the stiffness Is reduced significantly and the average stiffness is increased as increasing the contact ratio as shown in Fig. 11.AGMA 91FTM12 pdf free download.