Quick-release middle shaft crank assembly

The utility model relates to the technical field of assembly of a middle shaft and a crank. The utility model relates to a quick-release middle shaft crank assembly. The crank comprises a crank body,a middle shaft body, a connecting sleeve and a spline connector, spline connectors are symmetrically arranged at the left end and the right end of the middle shaft body; first sliding grooves are formed in the two spline connectors. Key columns are arranged in the two first sliding grooves. Limiting blocks are installed at the ends, away from the middle shaft body, of the two key columns. The connecting sleeve is welded to one end of the crank body, a sliding sleeve is arranged at the end, away from the middle shaft body, of the connecting sleeve, the sliding sleeve is arranged in a second sliding groove in the connecting sleeve, the sliding sleeve is slidably connected with the second sliding groove, and second trapezoidal grooves are symmetrically formed in the inner surfaces of the front side and the rear side