High-leakproofness threaded connector for solid expansion pipe in large expansion rate

The invention discloses a high-leakproofness threaded connector for a solid expansion pipe in the large expansion rate. The threaded connector adopts a direct-connection threaded structure and comprises an expansion pipe female buckle and an expansion pipe male buckle; the expansion pipe female buckle is sequentially provided a low-conicity single-hook-type female thread, tool withdrawal grooves, cylindrical surface sealing segments, a first-stage sealing groove and/or a second-stage sealing groove, conical surface sealing segments and negative-angle torque shoulders from the end to the interior; the expansion pipe male buckle is sequentially provided negative-angle torque shoulders, conical surface sealing segments, cylindrical surface sealing segments and a single-hook-type male thread from the end to the interior; the threaded connector adopts a double-channel multi-stage sealing structure, and particularly adopts a double-channel sealing mode of the third-stage sealing structure before expansion and the second-stage sealing structure after expansion. According to the high-leakproofness threaded connector for the solid expansion pipe in the large expansion rate, the thread deformation degree in the large expansion rate is reduced by adopting the single-hook-type thread tooth profile and the low-conicity thread design, the double-channel multi-stage sealing structure optimized through a large quantity of calculating tests meets the high-leakproofness property of the threaded connector deformed in the large expansion rate, and meanwhile machining and detecting are easy.