Milling machine spindle

The main shaft of the milling machine comprises an outer shaft and an inner shaft pivoted in the outer shaft, a bearing is arranged between the outer shaft and the inner shaft, and an end cover is arranged at the lower end of the outer shaft; a first channel is arranged in the end cover, a second channel is arranged in the inner shaft, the inlet end of the first channel is arranged on the outer wall of the end cover, the outlet end of the first channel is annular and arranged on the inner wall of the end cover, and the inlet end of the second channel is arranged on the outer wall of the inner shaft and corresponds to the outlet end of the first channel. The outlet end of the second channel is arranged on the lower end face of the inner shaft. The end cover is rotationally matched with the inner shaft to replace the function of a rotary joint, so that the channel can be positioned in the main shaft, the gas-liquid conveying structure is simplified, and the occupied space is reduced. 一种铣床主轴，所述主轴包括外轴和枢接在外轴内的内轴，所