| 摘要 |
An electric valve is provided to accommodate a speed reduction apparatus in a compact space of a rotor and provide a valve opening angle of high resolution, thereby providing a small and inexpensive electric valve. An electric valve includes a fixed gear, a ring gear(126), an output gear, an internal gear, and a planetary gear(150). The fixed gear has the ring gear. The output gear has the internal gear. A speed reduction ratio can be increased when a difference between teeth of the ring gear and the internal gear is small. In addition, since the speed reduction ratio in increase at a side having a large z3/z1, the number of teeth of a sun gear(56) is decreased. The number of teeth of the planetary gear is determined by the number of the teeth of the internal gear.
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