Dual-jacket type sealing structure transmission shaft

The utility model provides a dual-jacket type sealing structure transmission shaft which comprises an inner spline sleeve and an outer spline shaft pipe, wherein a first jacket pipe is welded on the outer spline shaft pipe; a rubber buffer gasket is pressed at the bottom in the first jacket pipe; a second jacket pipe is welded on the inner spline sleeve; the inner spline sleeve and the outer spline shaft pipe are in sleeve joint through a spline; the first jacket pipe covers the outer circle of the inner spline sleeve; the second jacket pipe covers the outer circle of the first jacket pipe; the second jacket pipe and the first jacket pipe are in clearance seal fit to form an annular sealing structure; and a bottom hole cavity of the inner spline sleeve is an oil storage cavity. When the transmission shaft works normally, the annular sealing clearance formed by the structure realizes a sealing dustproof effect, the high-precision fit between an oil seal and the spline sleeve in the conventional structure is av