Self-ring-disengaging synchronizer

The utility model discloses a self-ring-disengaging synchronizer which comprises a gear hub arranged on a transmission shaft, an outer spline of the gear hub is connected with an inner spline of a gear sleeve in a meshed mode, and the gear sleeve can axially slide relative to the gear hub so that the inner spline of the gear sleeve can be meshed with the outer spline of a combined gear. The bottomconical surface of the gear ring is selectively matched and rubbed with the top conical surface of the combination tooth to generate synchronous torque; a sliding block groove is axially formed in the periphery of the gear hub, a sliding block is arranged in the sliding block groove in a matched mode, and an outer spline meshed with the inner spline of the gear sleeve is arranged on the top faceof the sliding block. The side face of the sliding block is of a symmetrical structure, and a ring disengaging structure capable of selectively applying acting force to the gear ring is arranged on the sliding block. The gear