为了使瞄准线瞄准目标并使图像稳定，在潜望式上反射镜系统中多采用1比2传动机构。调研了现有的一些1比2传动机构，对这些机构的优缺点进行分析，在现有结构的基础上进行改进，最终设计了一种新型的1比2传动机构。设计的新型传动机构为滚动轴承式三连杆机构，摆杆与转杆之间通过轴承连接，把滑动连接转变成滚动连接，尽量减小了摩擦力矩，从而达到更好的稳像效果。实验表明，设计的1比2传动机构，结构简单、可靠性强、传递稳定性好、精度高且不受温度影响，能够很好的实现传递稳定精度。

In order to make the aiming line aim at the target and make the image stable, the 1:2 transmission mechanism is used in the periscope upper reverse mirror system. The existing 1:2 transmission mechanisms are investigated and the advantages and disadvantages of these mechanisms are analyzed. On the basis of the existing structure, a new type of 1:2 transmission mechanism is designed. The designed new type of transmission mechanism is a rolling bearing three connecting rod mechanism, which is connected by the bearing between the swing rod and the rotor, and the sliding connection is transformed into a rolling connection. The friction torque is reduced as much as possible so as to achieve a better image stabilization effect. The experiment shows that the 1:2 transmission mechanism has simple structure, good reliability, good transmission stability, high precision and without the influence of temperature. It can achieve good transmission and stable accuracy.