Second shaft hex key locating structure

The utility model relates to a locating structure, in particular to a second shaft hex key locating structure. The second shaft hex key locating structure comprises a second shaft. A male spline is arranged on the second shaft. A hex key is arranged in a tooth space of the male spline. The left end face of the hex key is axially located through a check ring and a spline gasket, wherein the check ring and the spline gasket are arranged on the second shaft. A pin hole used for installation of a cylinder pin is formed in the right end face of the hex key in the direction perpendicular to the length direction of the key. According to the second shaft hex key locating structure, the pin hole is formed in the tail end of the hex key, the cylinder pin is installed in the pin hole, the right side end face of the hex key is located through the cylinder pin and the pin hole, the left end face of the hex key is located through the check ring and the spline gasket, and therefore the hex key is prevented from axially moving. According to the second shaft hex key locating structure, the cylinder pin is installed on the hex key, and therefore assembly of a second shaft assembly is simplified.