Low-speed large-torque motor with built-in speed reducer

A low-speed large-torque motor with a built-in speed reducer comprises a shell, a magnet yoke, a permanent magnet, an armature and a multi-stage planetary reducer, an end cover is fixedly installed at the right end of the shell, the magnet yoke is concentrically and rotatably installed in the shell, the permanent magnet is concentrically and fixedly sleeved on the outer circumference of the magnet yoke, the armature is concentrically and fixedly installed in the shell and sleeved outside the permanent magnet, and the multi-stage planetary reducer is installed in the shell. The magnet yoke and the permanent magnet form a motor rotor, the armature forms a motor stator, an inner gear ring concentrically extending into the magnet yoke is integrally formed on the left side face of the end cover, the multi-stage planetary reducer is concentrically and rotationally arranged in the inner gear ring, and the magnet yoke is in coaxial transmission connection with the left end of the multi-stage planetary reducer. An out