| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized reduction gear and a film advance device for a camera which are composed of a small number of parts, compact, lightweight, quiet, excellent in transmission efficiency, low-priced, has high in a reduction ratio, and has a high breaking strength in spite of the small size thereof. SOLUTION: In a small-sized reduction gear comprising a planet gear mechanism composed of a sun gear 4, a planet gear 12, a holder 15 supporting the planet gear 12, a fixed internal gear 10 engaging with the planet gear 12, and a movable internal gear 20, a projection part 11 is formed on either one of an end part of the fixed internal gear 10 or an end part of the movable internal gear 20, and a recess part 21 fitting with the projection part 11 is formed on the other. The projection part 11 is fitted in the recess part 21 to guide a rotation of the movable internal gear 20. |
