Conveniently assembled and maintained axle speed reducer

The invention discloses a conveniently assembled and maintained axle speed reducer for solving the problems of more related parts in the assembly link, assembling quality and efficiency influences, field maintenance difficulty and the like existing in the existing traditional axle speed reducer. The conveniently assembled and maintained axle speed reducer comprises a speed reducer shell, a power input shaft supporting structure, an axle shell, a half shaft, a differential and a driven gear. The conveniently assembled and maintained axle speed reducer is technically characterized in that the power input shaft supporting structure is composed of two columns of bearings with the same outer ring structures, input torque flanges for fastening and supporting the bearings and locking nuts, wherein outer rings of the two columns of bearings are assembled in bearing assembling holes with the same internal diameters of the speed reducer shell; and inner rings are fastened and supported on the corresponding shaft diameters of a driving gear shaft through the input torque flanges and the locking nuts. The conveniently assembled and maintained axle speed reducer is simplified in structure, reasonable in design and convenient in assembling and field maintaining operations; and instability caused by speed reducer bearing assembling and pre-tightening and clearance variation is effectively eliminated, the bearing assembling precision is remarkably improved, the vibration noise and rotation resistance of the power input shaft supporting structure is reduced, and the service life of the speed reducer is prolonged.