| 摘要 |
PROBLEM TO BE SOLVED: To enable a power transmission mechanism to intercept the transmission of rotary power from a worm to a worm wheel in a condition that a large load is applied from an output side on the worm wheel in the power transmission mechanism which performs the transmission of the rotary power by a worm gear. SOLUTION: The power transmission mechanism is configured so that male screws 33A, 33B are formed on both ends of the worm 30 which composes a reduction gear 5 (the power transmission mechanism) and nuts 15A, 15B formed with female screws Aa, Ba capable of threadably engaging with the male screws 33A, 33B are integrally provided on a plug 4A of a body case 10 and an electric motor 4. Axial rotation moving relative to the body case 10 of the worm 30 is remained with stopped state because the engaged rotation reaches a terminate portion of a thread of the male screws 33A(33B) by threadably engaging either of the male screws 33A(33B) with the female screws Aa(Ba) when a load due to resistance from the output side is applied on the worm wheel 41 and thus a predetermined thrust force or larger functions on the worm 30. COPYRIGHT: (C)2011,JPO&INPIT
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