返回首页
当前位置: 主页 > 直升机资料 > 机务资料 >

Sun Gear Fault Detection on an OH-58C Helicopter Transmission(9)

时间:2011-10-26 20:59来源:蓝天飞行翻译 作者:admin 点击:
曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

(a)
(b)

Fig. 4. FM4 and Damage: TSA and Synthesized Signal

(a)
(b)

 

Fig. 5. FM4 and Damage: Single Tooth and Multiple Tooth Damage
of values when d(t) is converted back to the time domain. Its narrow histogram is shown in Figure 6c. The effect of multiple tooth damage is demonstrated in Figure 6b. The FM4 value for this case drops to 9.15 and the distribution, shown in Figure 5d indicates that the FM4 values does not continuously increase as the level of damage increases.
Planetary Gears

Planetary gears are a subset of parallel axis epicyclic gears for which the ring gear is .xed and the in/out mem-bers are the sun and carrier. This con.guration provides the bene.t of high load carrying capability in a compact design and is used throughout the helicopter and propeller-driven aircraft industry as well as in the resurgent windmill indus-try.
A schematic of the OH-58C is given in Figure 7.

In this example, the sun gear, located in the middle, is surrounded by four planet gears. The planet gears mesh simultaneously with the sun gear and the outer ring gear. The planets serve idler roles; thus, they are not considered in the .nal gear ratio. The planet gears are all attached to a carrier plate that rotates in the same direction as the sun.
In the helicopter reduction stage con.guration, the sun gear provides the input and the helicopter’s main rotor shaft is attached to carrier. The gear ratio is given by:
θsun Nr
=+ 1 (6)
θcarrier Ns

and since they are the same sign, rotate in the direction.
Analysis of planetary gear dynamics is complicated by the simultaneous meshing of multiple teeth. Figure 8 shows a typical baseline vibration spectrum for a two-stage heli-copter transmission that is used in this study. The spectrum is rich with components due to the pinion/bevel gear mesh of the .rst stage and the sun/planet/ring gear mesh of the second stage. Also included are components due to sur-rounding structures.
 
直升机网 www.helicopter.cn
直升机翻译 www.aviation.cn
本文链接地址:Sun Gear Fault Detection on an OH-58C Helicopter Transmission(9)

------分隔线----------------------------
  • 上一篇:没有了
  • 下一篇:没有了