Direct plug-in quick-connecting pipe fitting

The utility model discloses a direct plug-in quick-connecting pipe fitting which comprises a pipe fitting body, a core connected with the first end of the pipe fitting body, a fastening sleeve and an internal tooth washer. The core is sleeved with the fastening sleeve, one end of the fastening sleeve is detachably connected with the first end of the pipe fitting body, a gradual reducing opening is formed in the other end of the fastening sleeve, the internal tooth washer comprises a gasket and a plurality of elastic teeth connected with the gasket, the teeth are arranged obliquely towards the second end of the pipe fitting body, and the gasket is arranged between the fastening sleeve and the pipe fitting body. The internal tooth washer can be prevented from being damaged in the mounting process, therefore, the material selectivity of the internal tooth washer is increased, the internal tooth washer can be made of high-toughness materials, the ant-falling effect can be improved, the cost of the internal tooth washer is lowered, the cost of the direct plug-in quick-connecting pipe fitting is correspondingly lowered, meanwhile, the sealing performance is good, and the direct plug-in quick-connecting pipe fitting has the extremely good market prospect.