The invention discloses a precision rotational transmission mechanism, and aims to mainly solve the problems of complex structure,
low transmission efficiency, small output shaft, insufficient rigidity, weak
bearing capacity and
impact resistance, short service life, inconvenience in mounting due to an overlong worm, high
machining difficulty and high production cost of the existing positioning transmission mechanism. The precision rotational transmission mechanism comprises a rotation box which is arranged on a fixed rack, wherein a first transmission mechanism (namely a worm wheel and worm mechanism) is driven by a motor on the rotation box to drive a second transmission mechanism to work; the rotation box is driven by the second transmission mechanism to rotate by driving an output member and is provided with an output face which is connected with a load. The precision rotational transmission mechanism has the characteristics of compact and practical structure, simple structure, large
bearing surface of the output shaft, light overall weight, suitability for industrial production, high anti-
impact capacity and long service life; besides since a worm connecting shaft is additionally arranged in the first transmission mechanism, the overall length of the worm is shortened, the mounting and the
machining are facilitated, and the production cost is reduced.