| 摘要 |
A gear transmission for an electrical operation means is disclosed wherein a reduction gear mechanism is provided to reduce valve opening and closing speed. The gear box has a cylindrical shape in which upper and lower plates support two gear shafts which rotatably support a plurality of pairs of large and small gears. The large gear is integrally and coaxially secured to the small gear in each pair. A small gear of a first pair of gears supported by one of the gear shafts is engaged with a large gear of a second pair of gears supported by the other gear shaft. The small gear of the second pair is in turn engaged with a large gear of a third pair of gears supported by the one of the gear shafts. The third pair of gears is rotated about the one of the gear shafts independent of the rotation of the first pair of gears. This gear transmission is successively achieved between the two shafts dependent on the numbers of pairs of gears to realize the reduction gear mechanism, and the rotation of the motor shaft is transmitted to the transmission output shaft provided in the box, whose rotation is transmitted to a valve rod for opening and closing the valve. |
