Design Study of Self-Alining Bearingless Planetary Gear (SABP),
TRANSMISSION TECHNOLOGY CO INC FAIRFIELD NJ
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The subject study concluded that the SABP offers significant potential weight and reliability advantages over the contemporary two-stage helicopter power transmissions. Weight savings of 17 to 30 percent have been projected during this study, and a reliability improvement by a factor of 2 to 1 has been calculated. Considering other design parameters such as efficiency, vulnerability, helicopter transmissions. For lower gear reduction ratios, the SABP does not compare favorably with a single-stage planetary. The potential for weight and size reduction of this new transmission concept appears to lie in its ability to transmit higher torques in a given size due to improved load distribution among the planets and due to the elimination of the planet carriers and planet bearings. These improvements can have significant implications when space and weight limitations are imposed on the transmission designer. Considering the failure modes and vulnerability of contemporary helicopter transmissions and of the SABP, the new concept should be more tolerant to the loss of lubricant and loss of bearings. SABP has lower operating gear tooth stress levels, higher mechanical efficiency, and lower hear rejection rates. The most promising arrangements of the SABP studied are where the reduction ratios ranged from approximately 161 to 261.