Reduction gearbox and reduction gearbox assembly

The utility model relates to a reduction gearbox which comprises a main body and a planet carrier assembly installed in the main body. The first planet carrier assembly comprises a first planet carrier and a first gear rotationally and movably connected to the first planet carrier. The second planet carrier assembly comprises a second planet carrier and a second gear rotationally and movably connected to the second planet carrier. Wherein the first planet carrier assembly is connected with the second planet carrier assembly, and the tooth shapes of the first gear and the second gear are the same. Inner teeth matched with the first gear and the second gear are arranged on the inner surface of the main body, and the inner teeth are continuous everywhere. And the main body, the first gear and the second gear are made of plastic. According to the scheme, the noise of the reduction gearbox is reduced, and the sound quality is improved. The utility model further relates to a reduction gearbox assembly which compris