Valve opening display and self-locking device used on rotary motion valve

The invention relates to a valve opening display and self-locking device, in particular to a valve opening display and self-locking device used on a rotary motion valve. The invention solves the problems that the existing rotary motion valve with opening display function cannot directly and accurately indicate the true opening of the valve and the valve is not universal. A large gear is fixedly installed on the upper end surface of a bearing disc. The bottom end surface of the first limiting block and the bottom end surface of the second limiting block are relatively arranged on the bearing disc and are arranged on the two sides of the large gear. First teeth are arranged on a first locking head. Second teeth are arranged on a second locking head. The first teeth on the first locking headand the second teeth on the second locking head are engaged with the large gear. The lower end surface of a third limiting block is arranged on the bearing disc. Third teeth are arranged at the lowerpart of the third limiting block. The third teeth of the third limiting block are engaged with the large gear. The valve opening display and self-locking device can be installed on the supporting valve without changing the main body structure of the valve, the universality is high and the true opening of the valve is indicated.