Injection device with fixed dose self-destruction function

The utility model relates to an injection device with a fixed dose self-destruction function, and belongs to the field of sterile medical instruments. Comprising a core rod, an outer sleeve, a piston, an injection needle and an elastic clamping sleeve, the outer sleeve comprises a clamping self-locking section and a liquid cavity section, a self-destruction opening clamping groove is formed in the end, close to the liquid cavity section, of the clamping self-locking section, and a quantitative opening clamping groove is formed in the other end of the clamping self-locking section. The core rod comprises a clamping sleeve sliding section and a clamping sleeve limiting section; the elastic clamping sleeve is sleeved on the core rod; the elastic clamping sleeve comprises a clamping sleeve body and an elastic clamping jaw, the core rod is sleeved with the clamping sleeve body, the elastic clamping jaw expands outwards from the side face of the clamping sleeve body, a certain angle is formed between the elastic cl