Novel plunging joint structure

The invention discloses a novel plunging joint structure which comprises a three-pin shaft fork, a drum type three-axis pin, square blocks, roller needle retainers and waist drum-shaped roller needles. The three-pin shaft fork is provided with three axial grooves matched with the drum type three-axis pin and three axial grooves used for placing the square blocks, the portions between the two sidefaces of the square blocks and the side faces of the corresponding axial grooves used for placing the square blocks are each provided with one roller needle retainer, the roller needle retainers are provided with a plurality of roller needle placing grooves used for placing the waist drum-shaped roller needles, and the two side faces of the axial grooves used for placing the square blocks are provided with grooves matched with the waist drum-shaped roller needles. The drum type three-axis pin comprises a drum type three-axis pin body and positioning protrusions which are arranged on the drum type three-axis pin body a