Three-section type sliding rail with self-locking structure

The invention discloses a three-section type sliding rail with a self-locking structure. The three-section type sliding rail comprises an outer guide rail, an inner guide rail, a sliding strip and a self-locking functional assembly. The self-locking functional assembly comprises a fixing block and a self-locking mechanism, the self-locking mechanism comprises a rotating groove seat, a rotating shaft, a compression spring and a rotating clamping cap, a transverse through hole is reserved in the rotating groove seat, the axis of the rotating groove seat extends in the left-right direction, the left end of the rotating groove seat extends into and is fixed to a through hole of the fixing block, and a U-shaped clamping groove is formed in the right end face of the rotating groove seat; the rotating shaft movably penetrates through the through hole of the rotating groove seat; a limiting boss is arranged on the left side of the rotating shaft; the right end of the rotating shaft is fixedly connected with the left